Airway Management in Anesthesia and Emergency Medicine

Basic Airway Management, Intubation, and Anesthesia Equipment

A free airway is fundamental in all emergency medical activities when caring for critically ill patients. Oxygen deficiency due to a blocked airway is the single most important anesthesia-related cause of serious injury or perioperative death. This situation often arises with a patient who cannot breathe and cannot be ventilated. This is a scenario that everyone working in emergency care can encounter. Having a pre-planned action plan and access to relevant emergency equipment and intubation equipment is necessary to avoid serious incidents involving inadequate airway control in an anesthetized or unconscious patient. Intubating the patient means creating and securing a free airway.

The simplest way to create a free airway in an unconscious patient is primarily to place the patient in a lateral recumbent position with the upper arm’s hand under the chin. This method is often used on patients after anesthesia during a recovery phase or after discontinued ventilator treatment, such as after extubation following cardiac arrest.

At the beginning of anesthesia, the patient is usually placed in a supine position with the head elevated to best manage the airway and to intubate in the best way possible. The best position to manage the airway is behind the patient’s head. Initially, the patient is always manually ventilated with a breathing mask and bag. If the airway is obstructed by the posterior parts of the tongue, an oropharyngeal or nasopharyngeal airway can establish a free airway. There are several different models of these aids, as shown below. The airway is manually freed by a firm jaw thrust, the head is tilted back, and the jaw is lifted forward and upward as in a pronounced underbite. Manual ventilation with a breathing mask and bag is the basis for all airway management of an unconscious or anesthetized patient.

An oral airway may irritate the posterior pharynx and provoke gagging, vomiting, and laryngospasm if inserted into an insufficiently anesthetized or insufficiently unconscious patient. When correctly placed in a sufficiently anesthetized patient, it can be a great help in establishing a free airway. Therefore, an oropharyngeal airway should only be inserted when the patient is sufficiently anesthetized (non-responsive) or relatively deeply unconscious. A nasopharyngeal airway (NPA/”nasal trumpet”) is usually tolerated at a higher degree of wakefulness (preserved reactions) but can also irritate the posterior pharynx. Insertion of a nasopharyngeal airway must always be preceded by proper gel instillation in the nasopharynx to avoid nasal bleeding. Blood and mucus in the nasopharynx should always be avoided and removed when managing and establishing a free airway.

For an intubation attempt to be optimal, reasonable experience is required from the intubator, well-functioning laryngoscopes, the best choice of laryngoscope blade, type and size of the guide, optimal patient positioning, adequate muscle relaxation, and optimal positioning of the larynx. Under good conditions, intubation is usually not difficult, but difficult intubation can still arise unexpectedly. With the patient in a supine position, head elevated, well anesthetized, well-oxygenated, and fully muscle-relaxed, the best conditions are present for a successful intubation

Breathing Bag and Masks

Manual bag and mask ventilation is a basic skill for all airway management, which can be challenging to perform correctly. All airway management during anesthesia or emergency respiratory failure assistance starts essentially with manual ventilation with a mask and bag. This ventilation can be performed with a self-expanding or non-self-expanding breathing bag.

The self-expanding breathing bag, often called Ruben bag, Ruben balloon, Ambu bag, or hand ventilator, can be used with or without oxygen supply and therefore does not require connection to a ventilator or anesthesia machine. A hand ventilator is often used pre-hospitally and in emergency rooms at emergency departments or hospital wards, and in many other contexts where emergency ventilation may be necessary without a ventilator. A hand ventilator with a breathing mask can be used anywhere without access to other medical equipment. If possible, oxygen is connected via a simple rubber or plastic tube, and to achieve higher oxygen concentration in the inhaled air, a so-called reservoir balloon is attached to the breathing bag, see picture.

Usually, pure oxygen is used in the gas flow. The normal flow during ventilation with a hand ventilator is 5-10 liters of oxygen per minute. It is easy to provide excessive flows of oxygen over 10 liters per minute in the breathing bag, but this can make it difficult to compress the bag, reducing the manual feel for the patient’s lung compliance, and it is common to hear a whistling sound that creates stress and anxiety as well as communication difficulties among staff in an already tense emergency situation. Therefore, more than 10 liters of oxygen per minute should not be given.

The hand ventilator is usually made of silicone rubber with two valves, one at each end. Closest to the patient is a patient valve and at the other end, an intake or reservoir valve, see picture. These valves open and close synchronously with the airflow to direct the air in the right direction, in and out during breathing. Some hand ventilators are also equipped with an overpressure valve, especially when using smaller bags for pediatric use. A breathing mask for neonatal use, “neovent,” is entirely based on the principle of intermittent occlusion of an overpressure valve in a breathing mask without a breathing bag.

To ventilate with a hand ventilator, the patient must be ventilated via a tightly fitting breathing mask. These come in many different models and sizes. The flexibility or softness of the mask varies between different models. Nowadays, these masks are usually transparent and “semi-soft” to see the patient’s lip color and any foam or airway aspirate in the mouth or nose. A soft breathing mask can be challenging to seal tightly against the patient’s face, but it is usually just a matter of practice. The handgrip should be firm and determined yet gentle. Heavy beard growth and gastric tubes can significantly hinder the ability to seal tightly.

For adults, a mask size 4 (medium) or 5 (large) is usually used. On smaller adults, size 3 (small) can also be used. Overpressure ventilation via a hand ventilator and breathing mask is usually easier if a slightly smaller breathing mask is used. It is easier to get a tight seal than a large mask. For the ventilation to work, the mask must be tightly sealed, the gas flow adequate (neither too high nor too low), and sufficiently large tidal volumes can be delivered. Small tidal volumes less than 400 ml can provide adequate minute ventilation if compensated with a higher frequency (> 15 breaths/min). The advantage of smaller tidal volumes is that lower pressure can be applied, reducing the risk of blowing air into the stomach, which in turn can cause regurgitation of stomach contents with the risk of airway aspiration.

The respiratory minute ventilation must be adequate. A tidal volume of about 300-400 ml with a frequency of 15-20 is usually sufficient, but in some cases, both larger tidal volumes and higher frequencies are needed. If the patient is breathing on their own, it is important to try to synchronize the breaths with the patient so that the controlled ventilation assists the patient’s own breaths. This means adding a small tidal volume at the end of each breath the patient takes. The worse the patient breathes on their own, the more you need to take over with controlled breathing. If it is not possible to synchronize the breathing with the patient and the airway is threatened, it is generally advisable to relax the patient’s muscles and take over completely with controlled ventilation via intubation and an endotracheal tube or laryngeal mask.

If you insert an oral airway when the patient has fallen asleep, this may require moving up a size in the breathing mask. This change can be made simultaneously with the insertion of the oral airway. Some breathing masks are equipped with a double mask to extract excess anesthetic gases with active suction during inhalation anesthesia. This system is more environmentally friendly for the staff, but it is somewhat cumbersome and is used less frequently. Other masks have plastic hooks in a ring to secure the mask with rubber bands during mask anesthesia, but this is now very rarely used and has mainly been replaced by laryngeal mask anesthesia.

A non-self-expanding ventilation bag is usually used in a circle system connected to an anesthesia machine or a ventilator. To expand this balloon, air hoses connected in a circle system via an outflow valve, often called an APL valve (adjustable pressure limiting valve) or Bernerventil, are used. The APL valve regulates the resistance to flow in the balloon while functioning as an overflow valve where excess gases can exit via active suction. The airflow is set with gas rotameters, either physically or electronically, depending on the equipment. A common flow rate for ventilation with a non-self-expanding ventilation balloon is 8-10 l/min, but lower flow rates can also be used.

Oropharyngeal (OPA) and Nasopharyngeal Airways

Oropharyngeal and nasopharyngeal airways come in a variety of models and sizes. Both are intended to facilitate the creation of a clear airway in unconscious or sedated patients, which can create good conditions for manual ventilation with a mask and bag. The airways are usually placed with the patient in a supine position. Oral airways are inserted through the mouth and aim to open the occlusion between the back of the tongue and the pharynx, lifting the base of the tongue forward and upward.

When inserting an oral airway, it is important that the OPA is both the correct size and that the patient is sufficiently sedated/reduced in consciousness to accept an oral airway. If the OPA is too small, it may push the base of the tongue against the pharynx instead of lifting it forward. If the patient is inadequately sedated, an oral airway can provoke a gag reflex, trigger coughing, and in the worst case, cause laryngospasm. Thus, the OPA can hinder rather than facilitate the establishment of a free airway, but when handled correctly by experienced personnel, it is generally an excellent aid.

An oral airway should not be inserted in an inadequately sedated patient, and if a free airway is not well established at the start of anesthesia, it may be necessary to deepen the anesthesia before inserting the oral airway.

When inserting an oral airway, it is important that the distal end is properly positioned behind the base of the tongue. To achieve this, the jaw is lifted into an underbite position either by lifting the lower jaw from below (“jaw thrust”) or by pulling up the mandible with a firm jaw pull, taking hold of the lower jaw teeth if they are not fragile. Some oral airways have a central air channel that facilitates ventilation and can allow suctioning in the posterior pharynx, but suctioning is often cumbersome and difficult to perform through the oral airway.

During awakening, the oral airway is removed when the patient has intact swallowing reflexes. In a side position, a patient waking from inhalation anesthesia can accept an oropharyngeal airway for quite some time. If the patient spits out the airway or removes it by hand, the patient usually does not need the airway to maintain a clear airway.

Nasal airway (”Nasal trumpet/NPA”)

Nasopharyngeal airways (“Nasal trumpet”) are a good alternative to oral airways for creating a clear airway in sedated or unconscious patients. The advantage of a nasal trumpet compared to an oropharyngeal airway is that it causes less irritation in the posterior pharynx and is much less likely to provoke coughing, gag reflexes, or trigger a laryngospasm.

A nasal airway (nasopharyngeal airway) is therefore better suited than an oropharyngeal airway for a patient who is sedated but not deeply enough to accept an oropharyngeal airway. A nasal trumpet also better clears the posterior part of the tongue against the pharynx and more often creates a clear airway, especially in patients with a strong jaw or thick neck. However, it is not always that a nasal trumpet reaches down properly behind the base of the tongue. Neither an oropharyngeal nor a nasal airway is therefore a guarantee of a clear airway. The disadvantage of a nasal trumpet is instead a certain risk of nosebleed during insertion through the nostril. This risk can be avoided by properly lubricating both the nasal airway and the nasal opening. It is usually not enough to only lubricate the nasal airway; you need to insert a syringe with lubricant into the nasal opening and inject the lubricant to achieve good conditions. Excess lubricant can then be suctioned out through the nasal airway once it is inserted. Avoid overly stiff or sharp nasal airways that can damage the nasal septum and cause troublesome nosebleeds. Modern nasal airways are smoothly cut at the end to be gentle on the nasal septum. The cut makes them less suitable for insertion into both nostrils, as they are designed for either the right or left nostril.

Supraglottic Airway Device – SAD

Laryngeal Mask Airway (LMA)

The laryngeal mask is a type of medical device placed deep in the throat behind the tongue during general anesthesia to create a clear airway. A laryngeal mask can be used during general anesthesia with spontaneous breathing, assisted breathing, and controlled positive pressure breathing. With controlled positive pressure ventilation, there is a small risk that air will go not only into the lungs but also into the stomach during anesthesia, so laryngeal mask ventilation is best suited for spontaneous breathing. Laryngeal mask ventilation and controlled ventilation work well, but it is important to avoid too high peak pressures to reduce the risk of inflating the stomach, which increases the risk of aspiration. The duration of the procedure also matters; previously, a “rule of thumb” was not to choose procedures longer than an hour for laryngeal mask ventilation, but with modern and better laryngeal masks and good respiratory monitoring, longer procedures can also be performed safely. Patients at high risk for regurgitation and aspiration should not be anesthetized with a laryngeal mask but intubated instead.

Laryngeal masks come in many different models and materials, both with and without cuffs. They are available in many different sizes and are suitable for both adults and children. For outpatient anesthesia and many other procedures, laryngeal mask anesthesia is generally the standard when the patient is to be anesthetized in the supine position. In the lateral and prone positions, it is possible to anesthetize with a laryngeal mask, but it can present airway difficulties. Additionally, if problems arise, it is difficult to switch from a laryngeal mask to intubation with a patient in the prone or lateral position.

Laryngeal mask ventilation is unsuitable when the patient’s head is draped and inaccessible during surgery. High aspiration risk is a contraindication, as is laparoscopic surgery. High body weight is a relative contraindication; for a BMI over 40, another airway management method, usually intubation, should be chosen.

The laryngeal mask can be inserted using a guide or manually with fingers; usually, only hands and fingers are used. It helps if the mask is lubricated with some form of lubricant beforehand. The technique for inserting a laryngeal mask is quickly learned during routine anesthesia work. The patient should be well asleep and relaxed in the arms, shoulders, and jaw. The mouth should open easily. With an open mouth, under adequate anesthesia, the laryngeal mask is inserted through the mouth behind the tongue in an arc-shaped line. It may help to lift the lower jaw into a good underbite. It is important that the tip of the mask does not fold forward in the throat. The risk of this is greater with cuffed masks than with uncuffed ones, so the latter are often preferred. If the tip of the mask folds incorrectly, it can be corrected with an index finger deep in the patient’s throat. Cuffed masks should be inserted with the cuff deflated or “half-inflated.” In cuffed masks, the cuff is inflated with air after it is properly placed in the larynx until there is a resilient resistance but not “rock hard.” Usually, the cuff pressure in a laryngeal mask is not measured, but it is usually between 30 and 60 cm H₂O. The pressure should not exceed 60 cm H₂O. Once the mask is in place, check that the patient can be easily ventilated and that there are good air returns. There should be no leakage or leaking sound from the mask. The breathing curve (capnography curve – end-tidal CO₂) on the monitoring screen should be well-filled and should not have a sawtooth pattern during ventilation.

After anesthesia is completed, the mask is removed immediately after the patient opens their eyes and makes contact. It is important not to force the mask out at the end to avoid the risk of dislodging any loose teeth. Some throat discomfort (like a cold) may persist for a few days in the patient after laryngeal mask anesthesia.

Predictors of Difficult Laryngeal Mask Use

• Limited mouth opening
• Supra- or extraglottic pathology (radiation, large base of tongue tonsil)
• Glottic or subglottic pathology (laryngeal stenosis, etc.)
• Limited neck flexion.
• Cricoid pressure
• Increased BMI (>35)
• “Bad teeth”
• Position changes and surgical table rotations during surgery.
• Low lung compliance may require higher inspiratory pressure with the risk of air leakage.

Laryngoscope and Laryngoscope Blades

Laryngoscopes have been used for many years in anesthesia to intubate and visualize the larynx. A laryngoscope consists of a handle, a laryngoscope blade, and a light source, usually fiber optic with a rechargeable battery. The use of a traditional laryngoscope with direct vision has been the standard in anesthesia for decades for normal intubation. The laryngoscope provides direct visualization of the larynx, which can be advantageous in some situations, such as bleeding in the throat or for cleaning or removing foreign objects. The laryngoscope is typically made of metal but also exists in plastic. A metal laryngoscope provides a suitable weight in the hand during intubation, which creates conditions for steady maneuvers in the throat with a firm hand.

The laryngoscope consists of a handle and a detachable blade. The light source is located on the underside at the front end of the blade. All anesthesia personnel must be well-versed in assembling and disassembling this device. The handle comes in a standard version and a shorter variant suitable for intubation of patients with a short distance between the chest and chin. The handle contains a rechargeable battery, and the blade has a light source with fiber optics that provides a strong and clear light. Older laryngoscope models lacked fiber optics and provided significantly poorer light than today’s laryngoscopes. When not in use, the laryngoscope is usually placed in a charging station. Such a charging station for laryngoscopes should be available in all operating rooms and all intensive care units. There is usually space for two laryngoscopes, often one with a standard blade and one with a long blade.

The laryngoscope blade comes in several different models and sizes, both curved blades (Macintosh) and straight blades (Miller). Curved blades are used as standard. The blade is bent in a longitudinal segment to accommodate the tongue, which is moved to the side during intubation. There are also laryngoscope blades with a tiltable tip (“flexible tip”) to create more space and better visibility deep in the throat for difficult-to-intubate patients (“McCoy“). The bending of the laryngoscope blade is usually to the left, making it best to hold the laryngoscope in the left hand and enter the mouth from the right corner during intubation. The tongue is then moved slightly to the left so that the blade is centered in the mouth, and the distal end goes down into the larynx, where the tip is inserted above the epiglottis. Laryngoscope blades range in size from 0 to 5. Some hospitals refer to the blades by numerical size, but the most common practice is to refer to size number 4 as a “standard blade,” size number 5 as a long blade, and size number 3 as a short blade. Size number 4 is the standard for most anesthetics as a starting point. A long blade is usually chosen for intubation of heavy men with thick necks.

For intubation of children, shorter blades (size 0-2) and smaller laryngoscopes are naturally used. For neonatal children, it may be advantageous to use a straight blade during intubation rather than a curved blade. Laryngoscopes and laryngoscope blades come in a variety of models and designs. Some are named after the manufacturer, such as Miller (straight blade) and Macintosh (curved blade).

Pediatric laryngoscope Blade Size

Endotracheal Tubes in Different Models

Endotracheal tubes (ETT) are commonly referred to as “tubes” in daily anesthesia work. These are used to ventilate sedated or anesthetized patients with positive pressure ventilation. This is made possible by an inflatable “cuff” (balloon) at the distal end of the tube, which is inflated with air via a separate plastic channel. The inflated cuff prevents backward leakage of air outside the tube, thus allowing positive pressure ventilation and the use of PEEP. At the proximal end of the cuff channel, there is a valve that allows the cuff to remain inflated in the trachea. The cuff is inflated with 5-10 ml of air after intubation, in some exceptional cases with water. The cuff’s material and design vary, but there is a thought that the cuff pressure should not be too high to avoid mucosal damage in the trachea. Normally, the cuff pressure is set to 20-30 cm H₂O. The pressure should not exceed 30 cm H₂O. Normally, the cuff pressure is checked with a so-called cuff pressure gauge, which can also regulate the pressure. The cuff also prevents saliva and stomach contents from passing down into the trachea.

The tube enables positive pressure ventilation, prevents aspiration, and ensures a clear airway. Tubes come in various models and sizes. The tube is slightly curved to follow the anatomy of the throat and is usually made of transparent PVC plastic or opaque silicone rubber. The transparent variant softens when warmed, which can be utilized during nasal intubation. The curvature and shape of the tube vary depending on the procedure to be performed. For most anesthetics, standard tubes with only slight curvature are used, while for certain ear, nose, and throat procedures or plastic surgery procedures, special tubes with strong curvature or a swan-neck appearance are used (see images). The end of the tube is usually cut with the distal opening to the left, making it advisable to choose the right nostril to avoid traumatizing the nasal septum and risking a nosebleed during nasal intubation. In addition to a hole at the end of the tube, some tubes also have a side hole for air passage. This side hole reduces the risk of ventilation being blocked if the tube’s end gets stuck against the tracheal mucosa or a wall.

The length and thickness of the tubes vary. A typical standard tube is generally 27 cm long. Common sizes for adults are 6, 7, or 8. The size indicated refers to the inner diameter (ID) of the tube in millimeters. A size 7 tube works well as a standard for most adult patients (7 mm inner diameter ID). A size 6 tube can be chosen for small adults or teenagers. A size 8 tube can be chosen for heavy patients, mostly men.

Just proximal to the cuff, there are usually one or two black marks that facilitate tube placement during intubation. If there are 2 marks, the tube is placed so that one mark is below the vocal cords and one above. If the tube has only one mark, this is placed at the level of the vocal cords or just above. The tube is usually placed with a specified distance indicated by the centimeter marking at the corner of the mouth. The distal end of the tube should normally be 4 cm above the carina in the trachea. This is typical in most adults if the tube is fixed at 21-23 cm at the corner of the mouth. Deeper than 23 cm at the corner of the mouth is rarely needed, as it risks the patient being “right mainstem intubated,” meaning the tube goes down the right main bronchus, and the left lung becomes under-ventilated. The tube is fixed at the corner of the mouth with tape. There are several different techniques for fixation. In anesthetics where the patient’s head is draped or the patient is turned to the prone position, it is more crucial to secure the tube firmly, e.g., with a wide semi-flexible tape x 2. In regular anesthetics where the head and face are accessible, simpler taping may suffice. Proper ventilation is always checked after fixation before starting the operation.

Stylets for Endotracheal Tubes

A normal intubation without complicating factors can be managed without a stylet in the tube, but if the patient is difficult to intubate, intubation is facilitated by having a stylet in place. The primary function of the stylet is to create rigidity and better maneuverability during movements in the throat with the tube. The normally flexible tube is given greater control in the throat and larynx with a stylet, even if it encounters soft tissues. The stylet is usually removed when the distal end of the tube has passed the vocal cords. There are several different types of stylets for various occasions. During intubation with a video laryngoscope with indirect vision, it is advantageous to have a completely rigid stylet, such as a “Hyperangulated Glidescope Stylet.” This allows maneuvering through the throat even if it encounters soft tissues on the way down to the vocal cords and trachea. During intubation with video laryngoscopy and a steel stylet, it helps if an assistant presses down on the larynx from the outside during intubation.

Standard stylets have a soft atraumatic tip to avoid injuring the mucosa if it emerges first from the tube in the trachea. Standard stylets are semi-rigid (semi-flexible) so that they can be shaped into the correct form before starting intubation, such as a slight swan-neck shape. The distal end of the stylet should not protrude from the tube but lie just inside.

Other stylets, such as the elastic Bougie stylet, are long enough that the stylet can be inserted first and then the tube threaded over the stylet once the stylet has already passed the vocal cords. Oxygen can also be supplied through the stylet, allowing the patient to be continuously oxygenated. This long stylet can also be used during risky or questionable extubations from an airway perspective, such as in patients with swelling in the throat. The stylet can then be left in place after extubation, providing the opportunity for rapid reintubation if the patient experiences airway difficulties after extubation. Before this type of extubation, the patient can be anesthetized in the trachea by inhalation of nebulized anesthetic, e.g., lidocaine 40 mg/ml 2.5 ml. The tube and stylet may need to be lubricated before intubation with some form of lubricating solution.

Video Laryngoscope

There are several different video laryngoscopes that facilitate difficult intubations. There are two principal types of video laryngoscopes: one with a small screen attached directly to the laryngoscope handle and another with a video screen on a stand connected to the laryngoscope. The image can also be displayed on TV screens in the operating room or the room where you are. With an image on a video screen to the side, you get a larger and sharper image compared to a small screen on top of the laryngoscope. The small laryngoscope is convenient to take with you, for example, to an emergency room for handling acute trauma cases.

Compared to conventional laryngoscopy, video laryngoscopy provides excellent visibility of the larynx even in difficult-to-intubate patients who have deep throats or high-positioned vocal cords, Mallampati grades 3-4. The movements during intubation are slightly different compared to conventional intubation, requiring some experience to master the technique. In video laryngoscopy, it is natural and standard to intubate with a stylet in the tube, preferably a completely rigid steel stylet of the type “Hyperangulated Glidescope Stylet.” It is essential to choose the correct type of blade for video laryngoscopy and the appropriate stylet. Most video laryngoscopes are equipped with three different types of blades: a short blade, a long blade, and a long and extra-curved blade, known as the “D-blade.” For patients with Mallampati grades 3-4, the D-blade is generally best. During this type of intubation, it is helpful if an assistant can press down on the larynx slightly from the outside of the neck. The other two blades are more similar to a normal laryngoscope blade.

There are several types of video laryngoscopes, each with its advantages and disadvantages, see image below. Video laryngoscopy is the way of the future, and within 10 years, these will likely be standard equipment in every operating room, see below.

Intubation

Intubation is performed to secure the airway and allow controlled ventilation of the patient, thereby ensuring adequate oxygenation of the blood and proper elimination of carbon dioxide. Ventilation shifts from the patient’s own negative pressure ventilation to controlled positive pressure ventilation, either manually or mechanically. The patient can be ventilated using a breathing bag (“Ruben balloon/bag/silicone hand ventilator”) and a breathing mask or via an endotracheal tube or laryngeal mask. Usually, mask and bag ventilation are started to intubate during the induction of anesthesia.

To enable positive pressure ventilation, the endotracheal tube is equipped with an inflatable cuff that occludes the tube against the trachea on the outside and allows free air passage through the tube. The cuff is usually inflated with 5-10 ml of air. In small children, uncuffed tubes can be used as the trachea is narrow enough to allow positive pressure ventilation. Normally, manual ventilation is performed at a pressure of about 20 mm Hg with each breath. The ventilator can ventilate the patient with lower pressure if the lungs are healthy, approximately 8-14 mm Hg with each breath.

For an intubation attempt to be optimal, the intubator requires reasonable experience, a well-functioning laryngoscope, the best choice of laryngoscope blade type and size, appropriate stylet, optimal patient positioning, adequate muscle relaxation, and optimal larynx positioning. The patient should normally be well anesthetized and muscle relaxed when intubating the trachea. Typically, the patient is intubated orally through the mouth, and the tube is secured with tape to the cheek. In emergency situations such as cardiac arrest, intubation may need to be performed without muscle relaxants or sedatives, but this can be technically more difficult than with a well-anesthetized and relaxed patient. In certain circumstances, intubation may be necessary without deeply sedating the patient, such as in a difficult airway with maintained spontaneous breathing. In these cases, nasal intubation may be chosen instead of oral intubation under adequate sedation and local anesthesia (topical anesthesia). Most “normal” intubations, however, are performed orally with a well-anesthetized and muscle-relaxed patient.

Intubation – Practical Advice

The patient is most easily intubated in the supine position with a slightly elevated head end (30 degrees). After preoxygenation via a mask over the mouth and nose, the patient is anesthetized and muscle relaxed. Breathing is first controlled via mask ventilation, and a clear airway is created by firmly lifting the lower jaw forward into a strong underbite. If the tongue still obstructs the airway, an oropharyngeal or nasopharyngeal airway (“cannula”) can be inserted to optimize clear airway and ventilation conditions. When the patient is well-anesthetized and muscle relaxed, a laryngoscope is inserted through the mouth from the right corner toward the middle, carrying the tongue with it. A traditional battery-operated laryngoscope made of metal or plastic (metal is standard) with fiber optics or a video laryngoscope can be used, see below. Video laryngoscopes have either a small screen directly attached to the laryngoscope or a separate screen to the side. In traditional laryngoscopy, direct vision of the larynx is used, while with video technology, indirect vision via a screen is used.

It is important to insert the laryngoscope blade deeply into the throat. Then, steadily lift the tongue and lower jaw forward and upward in the direction of the handle, with a slight backward bend of the laryngoscope (not too forceful), while ensuring you do not hit the front teeth in the upper jaw. With this powerful lift, you can inspect the larynx and find the vocal cords and entrance to the trachea. You can then insert the tube. The tip of the laryngoscope blade is placed above the epiglottis (in the vallecula), causing the epiglottis to follow forward and upward with the lift you provide. Normally, you should not take the epiglottis with the laryngoscope blade; instead, the epiglottis should lift anyway. When you see the vocal cords, you can usually easily insert a tube between the vocal cords and down into the trachea. It is essential to see and identify the vocal cord opening during intubation.

To insert the tube, a slight clockwise twist of the tube may be needed when passing through the vocal cord opening. The tube is advanced about 8-10 cm below the vocal cords in an adult. An ideal position of the tube is with the distal end approximately 4 cm above the carina. At 8-10 cm from the end, most tubes have two marking lines; the distal black line should be below the vocal cords, and the proximal line should be immediately above the vocal cords. In adults, the tube is fixed at a marking of 21-24 cm at the corner of the mouth, where the tape is secured around the tube. To provide more stability to the tube during intubation, a flexible stylet can be used inside the tube, which is removed as soon as the tube has passed the vocal cords.

When the tube is in place, the cuff is inflated, and its position is checked and verified by:

1. Fogging in the tube back and forth during breathing (can also be heard and felt).
2. Listening with a stethoscope to hear breath sounds from both lungs during manual ventilation. Listen in at least four positions.
3. Verifying with capnometry that respiration is functioning through normal carbon dioxide elimination, indicating the tube is correctly positioned.
4. In uncertain cases, the tube’s position can be verified through bronchoscopy or X-ray. However, there is not much time to verify tube placement in an anesthetized patient. Capnometry and bronchoscopy are the most reliable methods.

Once the tube position is verified, it is secured by:

• Taping with some form of medical tape, preferably a three-pronged wide tape.
• Securing with a bite block (hard plastic clamp)
• Cotton bands tied around the tube.
• In rare cases, the tube can be secured by suturing (e.g., in craniofacial surgery), but tracheostomy tubes are usually secured by suturing.

In the event of an emergency, the surgeon is notified when the tube is fixed and the airway is secured.

Managing the Difficult Airway

Creating and maintaining a free and secure airway is always the primary concern in all anesthesia and intensive care. Failure to secure a free airway is both dangerous for the patient and anxiety-inducing for the anesthesiologist. The “can’t intubate, can’t ventilate” situation is fortunately very rare (about 1/10,000 intubations). Airway obstruction accounts for approximately 30% of very serious incidents related to anesthesia (death and severe brain injury). The danger lies in hypoxia, not a “lack of a tube.” Failed intubation accounts for about 10% of all difficult intubations, ranging between 0.13-0.3% of all intubations. In the “Fourth National Audit Project” (NAP 4 – UK), 184 cases of “Major adverse airway events” were recorded among 2.9 million anesthetics. To avoid these situations, it is important to conduct a thorough preoperative assessment of cases with difficult airways and prepare with the right equipment and sufficient competence before starting anesthesia.

Learn where the airway trolley is located in the operating department, what it contains, and how to use various airway aids.

Difficult laryngoscopy occurs when no part of the laryngeal inlet can be visualized during optimal laryngoscopy (Cormack Lehane grade III-IV). Difficult intubation also occurs when correct tube placement has not been achieved despite three optimal intubation attempts or within ten minutes of intubation attempts. A heavy man with a short, stiff neck and bull neck represents a typically difficult-to-intubate patient. In the event of a suddenly unexpected difficult intubation, it may be best to wake the patient and start over, for example, through awake fiberoptic intubation. Excessive mucus formation or bleeding in the nose and throat should always be avoided.

All operating departments should have access to some type of videolaryngoscope. Videolaryngoscopes have made it possible to handle many difficult airways better and intubate with reasonable risks. In most cases, videolaryngoscopes can reduce grading according to Cormack & Lehane’s by up to 2 units, e.g., from C&L grade 4 to grade 2. However, videolaryngoscopes do not solve all problems, and in very difficult cases, flexible bronchoscopes and the competence to use them are still needed. Ideally, establish an “airway room” one day a week in the regular operating department where you can train with various airway equipment, so everyone gains good competence. Preferably work in teams and apply the applicable airway algorithm.

Difficult airway can be categorized as follows:

1. Difficult mask ventilation (about 5%)
2. Difficult ventilation with a laryngeal mask (LMA/SGAD)
3. Difficult laryngoscopy
4. Difficult intubation (2-5-10%, up to 20% in ICU)
5. Difficult surgical airway

Tests for evaluating difficult intubation:

• Mallampati test
• Thyromental distance
• Mouth opening ability
• Neck mobility

Thyromental distance in centimeters is measured from the tip of the chin to the superior edge of the thyroid cartilage when the patient extends the neck maximally.

Risk factors for difficult intubation

• Small mouth
• Short neck, “bull neck”
• Large or loose teeth
• Bleeding or vomiting in the throat
• Inability to open the mouth or gape
• Anatomical anomalies in the oral cavity or throat
• Swelling in the oral cavity, tongue, neck, or throat
• Male gender
• Mallampati grade III or IV
• Sleep apnea syndrome
• Beard growth
• Age > 55 years
• Obesity, BMI > 26
• Tumors, infections, bleeding in the oral cavity or throat
• Previous radiation to the head and neck region
• Stridor
• Foreign body in the throat or upper airways
• Major trauma in the head or neck region
• Subcutaneous emphysema on the neck
• Horseshoe-shaped dental arch in the upper jaw

Assessment of airways

Various airway tests are intended to identify those with a difficult airway. A test with high sensitivity means that most people with a “difficult” airway are identified. A test with high specificity means that most people with an “easy” airway can be excluded.

Some of the most common methods for assessing the airway are as follows:

• Modified Mallampati (class 0-4)
• Thyromental distance (<6 cm, 6-7 cm >7 cm)(TM)
• Sternomental distance (<11 cm, 11-12.5 cm >12.5 cm)(SM)
• Wilson’s sum test
• LEMON-law
• “Upper lip bite” – test (ULBT)
• Mouth opening ability (<2 cm, 2-4 cm >4 cm)

No test is good enough on its own, but the combination of Mallampati and thyromental distance seems to be the best. Even better when the test is combined with long experience and good judgment. Patients with Mallampati class 0 (when the top of the epiglottis is visible) are almost always easy to intubate, provided there is no other laryngeal or tracheal pathology.

Patients at risk for pronounced hypoxia

• Unstable angina pectoris
• Severe CNS pathology including severe carotid stenosis
• Severe lung disease (COPD, fibrosis, etc.)
• High BMI (less oxygen reserves in the lungs)
• High metabolism: sepsis/pregnancy
• Decreased consciousness, unconscious patient
• Patient who has aspirated
• Emergency cases with injuries or swelling in the airways

In these patients, the airway must be secured in a “good” way with maintained oxygenation throughout the intubation. This means being more liberal in maintaining spontaneous breathing, avoiding apnea, and choosing a “safer” method, e.g., tracheostomy under local anesthesia, intubation with a flexible bronchoscope, or intubation with a videolaryngoscope under local anesthesia and possibly light sedation.

Predictors for difficult mask ventilation

• High BMI or high body weight.
• Old age
• Male gender
• Limited subluxation ability of the mandible.
• Short thyromental distance.
• Modified Mallampati class 3-4.
• Beard (can be shaved off!)
• Edentulism
• Snorer or OSAS
• Previous radiation to the neck.

Predictors for Difficult Laryngeal Mask Usage

• Limited mouth opening
• Supra- or extraglottic pathology (radiation, large base of tongue tonsil)
• Glottic or subglottic pathology (laryngeal stenosis, etc.)
• Limited neck flexion
• Cricoid pressure
• Male gender
• Elevated BMI (>35)
• “Bad teeth”
• Positional changes and operating table movements during surgery
• Low lung compliance may require higher inspiratory pressure with risk of air leakage
• Patients with Mallampati grade 1-2 appear to have more difficulty achieving a good position with the LMA without leakage compared to Mallampati grade 3-4

Predictors for Difficult Laryngoscopy

• Limited mouth opening (<4 cm)
• Limited subluxation of the mandible (ULBT 2-3)
• Narrow, often high, palate
• Short thyromental (<6-7 cm) and sternomental distance (<12 cm)
• Modified Mallampati class 3-4
• Hard floor of mouth
• Limited extension of the head and upper cervical spine
• Increased neck circumference = High collar size (>45 cm)

Predictors for Difficult Videolaryngoscopy

• Cormack-Lehane grade 3-4 on direct laryngoscopy
• Abnormal neck anatomy: radiation damage, scars on the neck, thick neck, and pathology in/on the neck
• Limited subluxation of the mandible
• Short distance between sternum and thyroid cartilage (larynx)

Management of Difficult Intubation

A successful intubation depends on the following factors:

• Is oxygenation satisfactory?
• Is ventilation (via mask or LMA) effective?
• Is there a risk of regurgitation or aspiration?
• Is additional help available nearby, and how quickly?
• Is there additional (known) airway equipment nearby? Airway cart!
• Application of airway guidelines for difficult intubation
• Anticipate difficulties – and be prepared!
• “Never fail to prepare for failure”
• Communicate your “Backup plan” – so colleagues know and understand
• Do not use techniques or equipment you are not familiar with
• “Learn to swim by swimming” – but practice in the shallow end of the pool
• Intubation should be good for the patient – not your “ego”. Patients do not die from failed intubation but from lack of oxygen!
• It is important to know your own limitations
• Know when to stop further intubation attempts – and how to proceed
• In case of failed intubation, consider:
  A. waking the patient
  B. laryngeal mask
  C. alternative techniques
  D. surgically securing the airway (knife, guide, & tube)
• Remember that the first intubation attempt is the best attempt
• Limit the number of intubation attempts to three or four

Management of Difficult Airway (Non-Emergent)

Planned anesthetics for patients with known airways should not pose significant problems if well-prepared with equipment and expertise. Tracheostomy under local anesthesia is “always right” for very difficult airways. As a second option, flexible bronchoscopy under local anesthesia with or without sedation should be used.

Awake Intubation

Patients with Known Difficult/Very Difficult Airway

• Various syndromes such as Pierre-Robin, Treacher-Collins, Crouzon, Goldenhar, etc.
  (There are many different syndromes with airway problems according to the literature, most are very rare)
• Various storage diseases such as Hunter’s and Hurler’s syndromes
• Reduced mouth opening (absolutely less than 2 cm and relatively 2-3.5 cm)
• Infections in the upper airways such as epiglottitis, floor of mouth cellulitis, severe mononucleosis, and tonsillar abscess, etc.
• Tumors, especially in the tongue, hypopharynx, and larynx. Patients with radiation treatment to the oropharynx
• Vallecula cyst
• Foreign body
• Laryngeal and tracheal stenosis
• Others with known difficult airway

Patients with Increased Risk of Vomiting and Aspiration

• Patients who have recently eaten/patients with gastroparesis
• Patients with severe reflux problems
• Patients with increased intra-abdominal pressure/volume such as ileus, late pregnancy, large abdominal tumors, etc.
• Trauma and patients who have received large doses of opioids
• Patients with nausea

Management of Difficult Airway (Emergent)

• Does this need to be done during on-call hours? Can the on-call specialist and ENT doctor arrive in time?
• Create a plan for this patient and communicate the plan and gather sufficient expertise
• Use an airway cart, but use equipment and methods you are familiar with
• Pre-oxygenate thoroughly. Continue with oxygen supply
• Optimal position, preferably “Sniffing position”
• Consider raised head end and cricoid pressure (release if difficult)
• If time and expertise are available, consider intubation with flexible bronchoscopy
• Otherwise, plan for videolaryngoscopy and guide
• If it is tight, use a smaller tube; a long 5 tube often works well
• Use a good laryngeal mask if initial intubation fails. A “good” laryngeal mask has: two lumens, one for an NG tube/guide and high seal pressure, can be intubated through with the help of flexible bronchoscopy
• Consider early surgical airway (cricothyrotomy, PCT, or surgical tracheostomy)
• Consider the possibility of transtracheal ventilation with Ventrain through a 2 mm needle/cannula. It is possible to ventilate 5-7 l/min with I/E 1:1. Ventrain is a new, inexpensive, and life-saving addition to the airway arsenal!
• There are methods we do not recommend, but which can solve an emergency situation but which can solve an urgent situation such as e.g. retrograde intubation, blind nasal intubation and digital intubation, i.e. you feel with your fingers in the throat and guide the tube in.

Fiber Optic Intubation

Fiber optic intubation, i.e., intubation using bronchoscopy, is a method every anesthesiologist should be well acquainted with. Fiber optic intubation is a technique where a flexible endoscope with a mounted endotracheal tube passes through the glottis. The tube is then pushed by the endoscope into the trachea, and the endoscope is withdrawn. This method is not routinely used for anesthesia but is regularly used when a difficult airway has been identified. Fiber intubation is usually performed with the patient in a semi-awake state with maintained spontaneous breathing under sedation. It is rarely performed with the patient fully anesthetized to better maintain the airway and spontaneous breathing. The procedure is therefore often called “awake fiber intubation”.

Fiber intubation is normally performed by guiding the fiber bronchoscope down into the larynx past the vocal cords and into the trachea, then advancing an endotracheal tube over the fiber bronchoscope. There are several different techniques for performing fiber intubation presented here. This is usually done electively, i.e., when a difficult intubation with a difficult airway has been anticipated, and muscle relaxation is avoided to maintain continuous spontaneous breathing and not risk having a patient with a difficult airway who stops breathing and might lose the airway completely. Fiber intubation can, in some cases, become necessary in emergency situations when oral intubation is not possible in the usual way, but it can be extremely difficult and complicated in situations where the patient is not breathing or has a lot of blood or secretions in the airways. Therefore, fiber intubation is primarily suitable for elective cases where intubation is performed calmly and steadily according to a pre-determined plan.

Indications for Fiber Optic Intubation

• Identified difficult intubation case
• Anatomical anomalies in the pharynx
• Small mouth
• Inability to open mouth, limited mouth opening, “trismus”
• Stridor
• Tumor in the throat or abscess compressing or displacing the vocal cord entry
• Trauma with fractures in the neck region
• Previous radiation treatment with scarring on the neck
• Patient who appears obviously difficult to intubate, for example, so-called “bull neck” or short and broad neck. Stiff neck. “Receding chin”.
• Dens fracture or other cervical spine fractures
• Severe burn on the neck

Before starting the planned fiber intubation, it is essential to be well prepared and go through the planned intubation with the anesthesia nurse, operating nurse, and other staff who will be present or assisting. In some high-risk cases, an ENT doctor or surgeon may need to be present in the room, ready to perform an emergency cricothyrotomy or tracheostomy. A fiber intubation of a patient with acute epiglottitis or severe stridor always needs a plan A and a plan B if plan A fails. In such a case, it may be a good idea to apply local anesthesia with adrenaline subcutaneously on the neck before starting fiber intubation in case you need to proceed with an emergency cricothyrotomy. In an emergency cricothyrotomy, bleeding in the wound is the most common complication, and using adrenergics in the local anesthesia is a good method to prevent bleeding.

Besides regular oral premedication, fiber intubation is usually performed with the patient well sedated, for example, with continuous infusion of remifentanil. The usual oral premedication can be given as usual, for example, Paracetamol 1 g + Oxycodone 10 mg to an adult of normal weight. After that, it may be appropriate to let the patient inhale local anesthetic with an oxygen mask and nebulizer, for example, 2 ml Xylocaine 40 mg/ml for 5 minutes to anesthetize the airways while giving an anticholinergic intravenously (Robinul 0.2 mg IV or Atropine 0.5 mg) to counteract excessive secretion in the pharynx. Blood and mucus are the worst enemies of fiber intubation and can cause intubation to fail.

Without mucus and blood in the pharynx and with effective sedation, fiber intubation is relatively easy to perform technically, but with a lot of mucus and blood, it is much more difficult. The patient is placed in a supine position, preferably with the head end raised. The nostril to be used for nasal fiber intubation should be gelled before starting intravenous sedation. Some type of gel, such as Instillagel, about 2 ml, can be administered by the patient actively sniffing it through the nostril so that the entire mucosa in the epipharynx down to the pharynx becomes soft and slippery. The bronchoscope needs to be lubricated before bronchoscopy, for example, with Dimethicone or silicone on the outside.

The tube to be inserted can be lubricated on the inside with, for example, a saliva substitute. It is essential that the tube and bronchoscope are dimensioned for each other and can glide against each other. A fiber bronchoscope that is 5 or 5.5 mm requires at least a 7-size tube to pass through. For a 6-size tube, a bronchoscope that is 4 mm fits, while a 5.5 mm bronchoscope is too large.

After this, intravenous sedation is started. Proper sedation is crucial for “awake” fiber intubation. There are several options for suitable sedation. The goal is for the patient to maintain breathing and oxygenation and not experience too much discomfort from the intubation itself. Continuous infusion with propofol can be difficult to manage and quickly lead to too deep anesthesia and is not recommended as a first choice. A small bolus dose of propofol (20 mg) can, however, be given for methods 1B and 2B when the tube is inserted through the nose, which can be uncomfortable. When the tube reaches the trachea, it usually irritates the airway, and the sedation can then be deepened directly after the tube is in place, transitioning from sedation to anesthesia. This is usually done by giving a bolus dose of propofol.

Sedation and other practical moments during fiber intubation

• Intravenous anticholinergic Glycopyrronium (Robinul) 0.2 mg or Atropine 0.5 mg should be given 30 minutes before to counteract mucus secretion
• Decongestant nasal drops in both nostrils
• Lubricate bronchoscope and tube with the appropriate lubricant
• If necessary, place an endotracheal tube in a bottle of hot water for 5 minutes to soften the tube (applies only to transparent tubes)
• Lidocaine (Xylocaine) 40 mg/ml, 2 ml nebulized in inhalation for surface anesthesia of the airways 5-15 minutes before intubation
• Lidocaine-Naphazoline nasally either via syringe or in an inserted tamponade
• Anesthesia with Xylocaine 10 mg/dose locally in the throat if needed
• Possibly Lidocaine 40 mg/ml 1-2 ml on the vocal cords via the bronchoscope when standing just above
• Provide oxygen via nasal catheter in the “wrong nostril” throughout the intubation
• Gel in the nose, about 2-3 ml as a lubricant
• Connect suction to the fiber bronchoscope
• Attach the tube without the connector with a piece of tape high up on the bronchoscope for methods 1 A and 2 A
• Midazolam 1-2 mg intravenously + an opioid of some kind:
  • Fentanyl 50-100 μg or
  • Alfentanil 500-1000 μg or
  • Remifentanil in infusion
    • TCI 1-2 ng/ml
    • TIVA 0.05-0.25 μg/kg/min

alternatively

• Ketamine 50-100 mg iv as needed
• Propofol in continuous infusion or in small bolus doses TCI 3 mg/ml
• Dexmedetomidin in continuous infusion
• Cricoid anesthesia. With a thin needle, the upper part of the trachea can be anesthetized with, for example, 3 ml lidocaine 10 mg/ml through transmembrane injection (through the cricoid membrane).

Sedation should be given so that the patient is well sedated with maintained spontaneous breathing and a free airway throughout the procedure. It is appropriate for the same person to have full attention on the sedation and the patient’s status during the fiber bronchoscopy (anesthesia nurse). The fiber intubation can then be performed with several different techniques, usually through nasal intubation with a sedated patient, but fiber intubation can also be done orally, which may be suitable for anesthesia of a patient with a neck injury lying in cervical traction. To perform oral fiber intubation, a special type of pharyngeal tube is required to hold the tongue and tongue base out of the way while allowing passage of the fiber bronchoscope (e.g., “Glenn’s pharyngeal tube”). This technique usually requires full anesthesia and may be suitable for a patient who, after anesthesia induction, proves to be very difficult to intubate. These cases are now primarily resolved with oral intubation using a video laryngoscope.

Fiber intubation can be performed in several different ways as follows

1. With the anesthesiologist standing above the head end. One stands in the same place as for regular intubation.

A. Bronchoscopy through the nose, through the oropharynx, and into the trachea before inserting the tube.

B. First, go down with the endotracheal tube into the oropharynx through the nose in deep sedation before bronchoscopy through the tube, through the oropharynx, and into the trachea.

2. With the anesthesiologist standing below the head end at the side of the patient, face to face with the patient

A. Bronchoscopy through the nose, through the oropharynx, and into the trachea before inserting the tube.

B. First, go down with the endotracheal tube into the oropharynx through the nose in deep sedation before bronchoscopy through the tube, through the oropharynx, and into the trachea.

3. Oral fiber intubation in anesthesia

A special pharyngeal tube is first inserted behind the tongue, after which bronchoscopy is done through the mouth, through the oropharynx, and into the trachea before inserting the tube.

Method 1 A With the anesthesiologist standing above the head end. One stands in the same place as for regular intubation.

The anesthesiologist stands above the head end. Bronchoscopy is done through the nose down to the carina before inserting the tube, which is first attached at the top of the bronchoscope.

You stand in the same place as during a regular intubation. A shorter anesthesiologist might need to stand on a chair. One advantage is that you are accustomed to standing in this position at the start of anesthesia. From here, you can easily ventilate the patient manually with a breathing bag and mask if needed, and you feel that you can control the airway in the same position you are most familiar with. You are close to the anesthesia machine and a short distance from the anesthesia equipment and suction. “Everything” is within reach. The tube is first attached with a piece of tape high up on the bronchoscope while identifying the glottic opening.

First, go down through the nose, pass the conchae, enter the pharynx, pass the base of the tongue, and then identify the glottic opening. Then pass through the glottic opening and go down into the trachea until you can clearly see the cartilage rings and the carina. A suitable stop is about 4 cm above the carina. The tube is then pulled down through the nose with a gentle but firm hand. When the tube is to pass the glottic opening, there may be a catch that is often resolved by rotating the bronchoscope and tube 90 degrees to the right. After that, the tube can usually pass the glottic opening. The bronchoscope is then removed while observing that the tube end is about 4 cm from the carina.

Advantage: It can be easier in complicated anatomical cases to find the glottic opening. It eliminates the risk of the tube being inserted too far into the pharynx initially, which can create difficult angles.

Disadvantage: The bronchoscope needs to follow an S-shaped curve similar to a swan’s neck. It is easy to get mucus or blood on the bronchoscope, which can hinder or obstruct visibility. Mucus in the nose can obstruct the view, unlike method B. Movements with the bronchoscope in the pharynx can trigger a cough or gag reflex. When the tube is to be inserted through the nose, it can be tight and difficult to pass the conchae. You do not know if the tube will be able to pass through the nose before finding the glottic opening.

Method 1 B With the anesthesiologist standing above the head end. One stands in the same place as for regular intubation.

The anesthesiologist stands above the head end. The tube is first inserted through the nasal opening before starting bronchoscopy.

Advantage: If the tube is inserted through the nasal opening before starting bronchoscopy, the bronchoscopy itself is usually easier and faster. Many times, the glottic opening is found directly in front of the bronchoscope when coming out of the tube in the pharynx. This is often the quickest and easiest method, avoiding prolonged fiber intubation. It is less bothersome for the patient when the bronchoscope passes through the nose through the tube than without the tube in place in the nose.

Disadvantage: There is some risk of nasal bleeding when first pulling the tube through the nasal opening, which may require some force. Nasal bleeding can be prevented with nasal drops and gel. It is also important to use a soft tube. A transparent endotracheal tube can be softened before intubation by placing it in hot water (45-50 degrees) for 5 minutes. The tube becomes soft and compressible. It is important that the tube is soft with this method; the walls should be able to compress against each other. There is a risk of the tube being placed too far into the pharynx through the nose, making the angle to the trachea too steep (S-shaped). This can make it difficult to find the glottic opening, and the problem is usually solved by pulling the tube back a few centimeters during bronchoscopy. The tube should pass the conchae in the nose down into the pharynx before bronchoscopy but should never be inserted too far, which makes intubation difficult.

Method 2 A With the anesthesiologist standing below the head end at the side of the patient, face to face with the patient

The anesthesiologist stands below the head end. You stand next to the patient, face to face. The advantage is that the bronchoscope gets an even curvature through the nose down into the trachea during bronchoscopy. An advantage is that you are in the right position if you need to perform a cricothyroidotomy or emergency tracheotomy on the patient.

It can be easy to perceive the anatomy as “upside down” through the bronchoscope, and right becomes left, but this is mostly a matter of habit. A disadvantage is that you are in the wrong position if you need to ventilate the patient manually with a mask and breathing bag.

You perform bronchoscopy before inserting the tube and pass the glottic opening before the tube is inserted through the nasopharynx. The tube is attached with a piece of tape high up on the bronchoscope while identifying the glottic opening.

Advantage: Less risk of nasal bleeding compared to method B. It can be easier in complicated anatomical cases to find the glottic opening. It eliminates the risk of the tube being inserted too far initially. Allows greater movements in the pharynx compared to method B.

Disadvantage: It is easy to get mucus or blood on the bronchoscope, which can hinder or obstruct visibility. The bronchoscope can scrape the nasal mucosa; it has sharper edges than the tube. Mucus in the nose can obstruct the view, unlike method B. Movements with the bronchoscope in the pharynx can trigger a cough or gag reflex. When the tube is to be inserted through the nose, it can be tight and difficult to pass through the nose. You do not know if the tube will be able to pass through the nose before finding the glottic opening. You need to move to the head end if you need to take over breathing manually.

Method 2 B With the anesthesiologist standing below the head end at the side of the patient, face to face with the patient

The anesthesiologist stands below the head end, near the patient’s armpit. The tube is inserted through the nasal opening before performing bronchoscopy.

Advantage: If the tube is inserted through the nasal opening before bronchoscopy, the bronchoscopy itself is generally easier. Often, the vocal cord opening is found directly in front of the bronchoscope when it exits the tube in the oropharynx. This is often the quickest and easiest method, avoiding prolonged fiberoptic intubation. It is less bothersome for the patient when the bronchoscope passes through the nose via the tube than without the tube in place in the nose.

Disadvantage: There is a risk of nasal bleeding when the tube is first inserted through the nasal opening. Nasal bleeding can be prevented with nasal drops and gel. Only a soft tube should be used. A transparent endotracheal tube can be softened before intubation by soaking it in hot water (45-50 degrees Celsius) for 5 minutes. The tube thus becomes soft and compressible. It is important that the tube is soft for this method, and the walls should be able to compress completely. There is a risk of inserting the tube too far into the pharynx, creating an S-shaped angle to the trachea. The tube should pass the conchae in the nose but should never be inserted too far, as this complicates intubation.

Method 3

Oral Fiberoptic Intubation

A special oropharyngeal tube is first inserted behind the tongue, then bronchoscopy is performed through the mouth, through the oropharynx, and into the trachea before inserting the tube. This is suitable, for example, for patients with neck fractures in cervical traction where one wants to avoid cough reflexes and sudden neck movements during intubation. The patient is anesthetized as usual in a flat supine position intravenously and muscle-relaxed. Then a special oropharyngeal tube (e.g., Glenn’s oropharyngeal tube) is inserted to allow fiberoptic intubation. The tube is threaded over the bronchoscope, and when the tube passes the vocal cord opening, the oropharyngeal tube is removed, and the tube is advanced over the bronchoscope into the trachea. It may help if an assistant performs a jaw thrust during intubation by lifting the mandible forward and upward.

The procedure is relatively simple if the oropharyngeal tube can create a free airway and allows the passage of the bronchoscope. It is important to use effective lubricants to prevent the bronchoscope from getting stuck in the oropharyngeal tube. The bronchoscope should be lubricated on the outside (silicone or similar, but not xylocaine gel), and the tube on the inside, e.g., with saliva replacement spray. The patient can be manually ventilated before intubation.

Emergency Cricothyrotomy

Cricothyrotomy (also called emergency tracheotomy) is an emergency surgical incision through the skin and cricothyroid membrane (Ligamentum cricothyroideum medianum) into the trachea to create a free airway. The cricothyroid membrane is a connective tissue membrane between the thyroid cartilage and the cricoid cartilage. It is a last-resort life-saving measure when all other methods to create a free airway have failed, and it is not possible to wait for the extra time required to perform a tracheotomy. A cricothyrotomy is a temporary solution and is therefore often followed by a tracheotomy.

Predictors for Difficult Cricothyrotomy

• Difficulty identifying the cricothyroid membrane
• Female gender
• Children before puberty (<8-12 years)
• Thick or obese neck
• Local pathology (inflammation, radiation, tumor, etc.)
• Difficulty accessing the trachea through the front of the neck
• Thick neck with pathological changes
• Fixed neck with limited movement
• Neck fracture

Percutaneous Tracheotomy

Percutaneous tracheotomy is performed when a prolonged ventilator period is expected, usually over 7 days. The procedure can be performed earlier than 7 days if it is already clear that the expected ventilator period will be long.

Percutaneous tracheotomy is a surgical procedure usually performed by anesthesiologists in an intensive care unit. The procedure is performed using a dilation technique where a small skin incision is made at the jugulum, dissecting down to the trachea with a pean and then puncturing the trachea under simultaneous visualization through a bronchoscope in the existing endotracheal tube.

Here are some small tips and advice for percutaneous tracheotomy.

You need at least one operator performing the tracheotomy itself and an assistant managing the upper airway. The operator can be assisted in the wound, and the person managing the upper airway can have additional help to hold the tube in place with two fingers when it has been backed up considerably.

The patient is normally intubated orally. Start by positioning the patient in a supine position with a gel pad under the shoulders and head tilted back. The head should never hang freely; the back of the head must be supported by a suitable pillow. The patient should be pulled high up in the bed towards the head end to facilitate for a doctor assisting with bronchoscopy during the procedure. Place video monitors for laryngoscopy and bronchoscopy on the patient’s left side if the operator stands on the patient’s right side (suitable for right-handed individuals).

Start by administering local infiltration anesthesia in the jugulum, e.g., 10 ml Xylocaine-Adrenaline solution (10 mg/ml + 5 micrograms/ml). The local anesthetic is infiltrated very superficially in the skin and then towards the trachea at 12, 15, and 21 o’clock. It is important to use a local anesthetic with adrenaline to achieve vasoconstriction in the wound. Usually, no hemostasis other than cotton compresses is needed, but in some cases, small vessels may need to be cauterized.

Place a neckband (trach band) under the patient’s neck from the start before the area is sterilized. Change the connector to the tube that allows bronchoscopy through a slit.

The ventilator must always be set to controlled ventilation, and alarm limits may need to be adjusted. You can adjust the ventilation to about 25 breaths per minute and 400-500 ml tidal volumes. The inhaled oxygen concentration is adjusted as needed, sometimes up to 100 percent. The procedure is performed under good sedation, and the patient is muscle relaxed, usually with rocuronium 50-100 mg intravenously.

The assistant performing bronchoscopy starts by suctioning and cleaning the oral cavity. Both a video laryngoscope and a bronchoscope may be needed to manage the upper airway. You can use one or two video monitors. Start with bronchoscopy for coarse cleaning of the trachea. Then clean the oral cavity with suction and swabs before backing up the tube with the help of a video laryngoscope. Usually, two separate suctions are needed.

The surgical area is cleaned with chlorhexidine and draped with four sterile drapes. After checking in, the procedure starts with the operator making a small skin incision at the jugulum level, about 2-3 cm wide, under sterile conditions. Then blunt dissection down to the fascia above the trachea, which often appears slightly bluish. The assistant then backs up the endotracheal tube so that the upcoming puncture into the trachea can be visualized via the bronchoscope. The tube must be backed up high enough to see the puncture from inside the trachea on the video screen. It is important that the assistant positions the bronchoscope so that the “roof” of the trachea is visible upward on the video screen, visible to both the assistant and the operator. The tube usually needs to be backed up so that the cuff is above or just proximal to the vocal cords, typically at 15-16 cm from the corner of the mouth. If the cuff is backed up completely proximal to the vocal cords and inflated, this step is sometimes called the “Ping-Pong method.” The inflated cuff then presses against the vocal cords. The step with the backed-up tube usually results in some air leakage during ventilation, but ventilation is generally satisfactory.

In the next step, it can be helpful to dim the lights in the room, allowing the person performing bronchoscopy to illuminate the trachea’s roof. The operator can then see the red light in the wound and puncture with a needle at that spot. The puncture should hit the trachea in the midline, at 12 o’clock. Typically, a needle attached to a 5 ml syringe with saline is used. The puncture is performed under aspiration, with air bubbles appearing in the syringe upon entering the trachea. The puncture should be made between the second and third tracheal rings or between the first and second rings. This usually makes it easier to achieve a good hit in the trachea, visible on the video screen. The needle is inserted into the trachea over the needle and angled down towards the carina. Care must be taken to avoid puncturing the trachea’s back wall. Note that the trachea often descends deeper the further down you go. The puncture angle should account for this.

After the plastic cannula is inserted into the trachea, a metal guidewire is advanced to the carina through the cannula. Then the plastic cannula is removed, and a primary short and firm (usually white) dilator is inserted into the trachea under visualization via the bronchoscope. This primary dilator should be inserted deeply, then in and out three times. In the next step, the conical secondary dilator (“Blue rhino,” “White rhino”) is inserted, which in turn has a thin white dilator with a flange holding against the conical dilator’s opening. This conical dilator is advanced into the trachea until a black mark is seen just inside the trachea (visible via the bronchoscope). In this position, the dilator is held in place for 30 seconds, then moved in and out of the trachea three times. After this, the dilator and the thin white dilator are removed, but the metal guidewire remains. The thin dilator is then applied to the tracheal cannula, which has a firm conical obturator. The tracheal cannula is then inserted into the trachea with a firm but careful hand motion. When the cannula passes through the tracheal wall hole, it may feel like a “pop.” The obturator and guidewire are then removed from the tracheal cannula, and the bronchoscope is immediately used to inspect that the cannula is correctly placed in the trachea. Suctioning of some mucus and secretions may be needed. The ventilator is then connected to the tracheal cannula. The tracheal cannula is secured with the neckband, but first, a flat compress is placed under the wings of the cannula, “Metallin compress.”

Finally, remove the gel pad from under the neck and adjust sedation and ventilator settings. The neckband may need to be tightened after the gel pad is removed. The patient should be kept well sedated for at least an hour after muscle relaxation is administered.

Extubation

Extubation is the removal of the endotracheal tube performed after anesthesia or intensive care with intubation and ventilator treatment. The tube is removed when the patient can breathe satisfactorily on their own without becoming exhausted and without the risk of desaturation. Extubation of an exhausted patient is contraindicated. Acceptance of 5 over 5 in support pressure/PEEP with FiO₂ below 0.3 is considered a safe measure to extubate from. Even higher pressure levels can be used for extubation in some cases. It is always an advantage if the patient is communicative and calm during extubation. “Crash extubation” should be avoided.

Criteria for Extubation

• Spontaneous eye opening
• Facial grimacing
• Patient movement other than coughing
• Conjugated gaze
• Purposeful movements
• End-tidal levels of anesthetic gas lower than:
  • Sevoflurane: 0.2%
  • Isoflurane: 0.15%
  • Desflurane: 1.0%
• Oxygen saturation higher than 97%
• Positive laryngeal stimulation test
• End-tidal volume greater than 5 ml/kg

Assess the Patient’s Ability for Spontaneous Breathing Before Extubation

• Can the patient have assisted ventilation in the ventilator?
• Are acceptable values for TU, PEEP 10, FiO2 <40% present?
• Are blood gases with SaO2>95%, PaO2>10 kPa, PaCO2<6 kPa available?
• Reduce to extubation settings with PEEP 5-7 and TU 5-7

Extubation Criteria

• Awake RLS <3?
• Pharyngeal function, cough strength?
• Handles PEEP 5-7 and TU 5-7 or freely on the nose > 30 min?
• Expected free airway after extubation?

Evaluation After Extubation

• Pulse, blood pressure, respiratory rate, blood gases?
• Within individually set limits?

1. Note: A pilot must plan both the start (intubation) and the landing (extubation).
2. Extubation is always elective (unless accidental).
3. 23% of severe airway-related incidents occur during extubation.
4. The most common complications during extubation are hypertension, tachycardia, increased intracranial and intraocular pressure, etc.
5. Common problems: Inadequate oxygenation and ventilation. Inability to protect the airways and clear mucus from the airways.
6. During extubation, plan for the possibility that extubation may fail.
7. During extubation, assess whether reintubation can be easy or difficult.
8. Reintubation under optimal conditions is very different from emergency reintubation with a hypoxic patient.
9. Consider a laryngeal mask as a “bridge” during extubation.
10. Consider extubation over an “Airway exchange catheter.” Pre-treat with inhalation of lidocaine.

When giving patients anesthesia, one can often choose between general anesthesia or some type of regional block, central or peripheral, in combination with sedation for the surgical procedure. It can be tempting to choose regional anesthesia for patients with difficult airways, but in such cases, one must choose a variant that “surely works,” e.g., spinal anesthesia. If a block stops working during surgery and you are forced to induce anesthesia in a patient with a difficult airway, you can quickly end up in serious trouble.