Author:
Kai Knudsen
Updated:
26 August, 2025
This chapter describes the essential elements of the preoperative assessment of a patient before anesthesia as well as guidelines for preoperative fasting. Preoperative assessment, guidelines for intake of solid food, medications that should also be given on the day of surgery and choice of anesthetic methods (anesthesia plan) for various surgical interventions are presented here.
Preoperative assessment
During the preoperative assessment, the patient’s health is evaluated and the type of anesthesia for the surgery is determined. The patient is informed about the perioperative process during the preoperative conversation. The appropriate premedication and which regular medications should be taken on the day of surgery are prescribed. The preoperative assessment benefits both the patient and the anesthesiologist, determining the form of anesthesia and the surgical procedure.
Common Design of Anesthesia Form
Anesthesia forms are typically designed to provide a comprehensive overview of the patient’s medical history, current medications, allergies, and specific anesthesia plan. They include sections for preoperative assessment, intraoperative management, and postoperative care. The goal is to ensure a safe and effective anesthesia experience tailored to the patient’s individual needs and the specific surgical procedure.
The anesthesia form usually includes the following sections:
- Patient Information: Name, age, sex, weight, height, and contact information.
- Medical History: Previous surgeries, chronic illnesses, and relevant family medical history.
- Medications: Current medications, including over-the-counter drugs and supplements.
- Allergies: Known allergies to medications, foods, or other substances.
- Preoperative Assessment: Physical examination findings, laboratory results, and any preoperative tests (e.g., ECG, X-rays).
- Anesthesia Plan: Type of anesthesia (general, regional, local), induction agents, maintenance agents, and airway management plan.
- Intraoperative Management: Monitoring plan, fluid management, blood products, and medications to be administered during surgery.
- Postoperative Care: Pain management plan, monitoring in the recovery room, and any specific postoperative instructions.
- Signatures: Anesthesiologist and patient (or legal guardian) signatures to acknowledge the anesthesia plan and consent.
It is crucial to review and update the anesthesia form regularly to reflect any changes in the patient’s condition or surgical plan. This ensures that all team members are aware of the latest information and can provide the best possible care.
The preoperative assessment usually takes place one or more days before surgery. In emergency cases, it is performed close to the upcoming surgery. The patient’s health is assessed by reviewing the medical history, available medical records, and other relevant data (lab tests, ECG, X-rays, etc.). The patient’s health is primarily evaluated regarding heart and lung function but also overall health to identify other possible risk factors for the upcoming anesthesia such as difficult airway, severe obesity, difficult venous access, increased bleeding tendency, serious allergies, poor general condition, care issues, etc.
The type of anesthesia is planned and determined, including airway management, induction agents, analgesics, muscle relaxants, anesthesia maintenance, and postoperative pain relief. The type of anesthesia to be administered is decided; TIVA, TCI, inhalation, or combination anesthesia. Airway management is planned with options such as oral intubation, nasal intubation, fiberoptic intubation, video laryngoscopy, mask anesthesia, laryngeal mask, or spontaneous breathing (mask, oropharyngeal airway, or oxygen catheter). The potential use of regional anesthesia with blocks is determined. The type of anesthetic equipment and monitoring to be used, such as central venous catheter (CVL), arterial line, epidural anesthesia (EDA), ultrasound, etc., is planned. Advanced equipment like cardiac output monitoring or arterial pressure waveform analysis (e.g., Swan-Ganz, LiDCO, Cardio-Q, thermodilution, PiCCO, NiCO, Vigileo, etc.) may be considered for major surgery or hemodynamically unstable patients.
Preoperative Investigation – Assessing the Patient’s Condition and Ability to Undergo Surgery
Simple risk assessment before surgery can be done using a defined “MET score”.
METS is an abbreviation for “metabolic equivalents,” a standardized measure of energy expenditure that estimates the patient’s physical condition. A MET score <4 is associated with an increased incidence of perioperative cardiac complications (based on thoracic surgery patients).
The risk of surgical complications primarily depends on the patient’s physical condition and the type of surgical procedure. Below is a generalized risk assessment adjusted for the type of surgery.
Preoperative Investigation – Risk Index
Lee et al. published a cardiac risk index from 2893 patients validated in 1422 patients aged ≥50 years undergoing major non-cardiac surgery, known as the Revised Cardiac Risk Index (RCRI). Lee identified six independent variables predicting an increased risk of cardiac complications. This index predicts the risk of postoperative myocardial infarction, pulmonary edema, ventricular fibrillation, cardiac arrest, or complete AV block. The six variables are:
- Type of surgery?
- Ischemic heart disease?
- Heart failure?
- Cerebrovascular disease?
- Insulin-treated diabetes?
- Preoperative creatinine >170 mmol/L?
NSQIP MICA (American College of Surgeons’ National Surgical Quality Improvement Program)
The NSQIP risk of myocardial infarction and cardiac arrest is calculated based on the following variables:
- Type of surgery
- Patient’s condition
- Creatinine >130 mmol/L
- ASA class
- Age
Other Factors Affecting the Patient’s Risk of Complications:
- Frailty score
- BMI
- Anemia
- Immune status
Preoperative Investigation – Examinations
ECG is routinely checked preoperatively in patients over 50 years or patients with known cardiovascular disease. For those under 50 years, ECG is only taken on specific indication.
- ECG is usually analyzed for:
- Q wave, significant ST changes, LV hypertrophy, prolonged QTc time, bundle branch block, arrhythmias, or other abnormalities
Additional clinical physiological examinations should only be performed on patients at high risk for perioperative cardiovascular events, such as those with a recent myocardial infarction, unstable angina, decompensated heart failure, arrhythmias, or hemodynamically significant valve disease. Relevant preoperative examinations include:
- UCG
- Holter-ECG
- Exercise ECG
- Coronary angiography
- Spirometry
- Chest X-ray (thorax)
Examinations whose results will not affect or improve the anesthesia process or outcome are not indicated preoperatively.
Cardiology Consultation or Other Specific Consultation Can Be Performed If Needed with Possible Preoperative Optimization
Preoperative Investigation with Biomarkers
- TnI/TNT – prognostic value
- Can be taken in high-risk patients pre- and postoperatively – with assessment of myocardial injury
- NT-proBNP
Patients Are Considered High-Risk If:
- MET ≤4
- Revised Cardiac Risk Index >1 for vascular surgery (>2 for non-vascular surgery)
ASA-classification
| ASA class | Classification of patients according to disease state and fitness |
|---|---|
| ASA I | A normal healthy person. Example: No organic, physiological or psychological disorder. Good physical function. Age < 80 years. |
| ASA II | Patient with moderate systemic disease. Well-controlled disease in an organ that does not cause functional limitation: eg diabetes without organ involvement, hypertension, smokers without COPD, obesity with BMI >30 but <35. Pregnancy. |
| ASA III | Patient with severe systemic disease. Controlled disease state in more than one organ or severe disease state in one organ that causes functional limitation: eg diabetes with organ involvement, previous myocardial infarction (>6 months), angina pectoris, well-controlled heart failure, kidney failure, poorly controlled hypertension, obesity with BMI > ;35. |
| ASA IV | Patient with a severe systemic disease that is a constant threat to life. Severe systemic illness that is potentially life-threatening. The functional limitation may be conditioned by the current disease for which the patient is to be operated on or by another pathological process: e.g. unstable angina pectoris, resting angina, pronounced heart failure, recent heart attack (>6 months), ongoing heart attack, advanced pulmonary, renal or liver failure. |
| ASA V | A moribund patient who is not expected to survive without surgery. Patient who is not expected to survive 24 hours without surgery: eg ruptured aortic aneurysm in shock, multi-organ failure, sepsis with hemodynamic instability. |
In addition to a preoperative risk assessment, the preoperative assessment should plan the setup on the operating table before surgery and assess the expected amount of bleeding.
Intravenous fluid administration and the ordering of blood products are planned. In the preoperative assessment, the ASA grade (I-IV) and intubation grade with Malampati grade I-IV, SM distance (sternomental distance), TM distance (thyromental distance) should be determined. Previously known intubation problems and other known anesthesia complications should be noted. The need for sedation, PONV prophylaxis, and postoperative pain management should be determined.
Common options of anesthetic agents
| Induction agent | Analgesics | Muscle relaxant | Anesthesia maintenance | Inotropic support | Postoperative pain relief |
|---|---|---|---|---|---|
| Propofol | Fentanyl | Suxamethonium | Sevoflurane | Phenylefrine | Morphine |
| Thiopentone | Alfentanil | Rocuronium | Desflurane | Norepinephrine | Ketobemidone |
| Ketamine | Remifentanil | Vecuronium | Isoflurane | Epinephrine | Epidural block |
| Sevoflurane | Sufentanil | Atracurium | Ketamine | Vasopressine | Paracetamol (acetaminophene) |
| Propofol | Argipressine | Oxicodone | |||
| Remifentanil | Ketamine | ||||
| Alfentanil | Clonidine |
Any allergies should be noted, especially to medications such as antibiotics, ASA, NSAIDs, or local anesthetics. Are there any specific care issues? Problems with positioning should be noted, such as lateral position, kidney position, prone position, prayer position, high leg supports, etc. Relevant lab tests are reviewed and the current EKG is evaluated.
After the preoperative assessment, premedication and anesthesia form, as well as any additional examinations or investigations needed before the upcoming surgery, are determined. Examples of additional examinations may include chest X-ray, cardiac ultrasound (UCG), exercise test, or spirometry. The extent of the additional examination should be minimal but still ensure that the patient will be in optimal condition for surgery.
In the preoperative conversation, the patient should be informed about the upcoming surgery and anesthesia. The patient usually wants to know when, where, and how the surgery will be performed. Unfortunately, this information is often missing during the preoperative assessment. The patient should be informed in a way that makes them feel calm and confident about the upcoming surgery. The same applies to children and their parents. This requires the anesthesiologist to be well acquainted with the patient’s health and able to assess various risk factors, as well as the nature of the upcoming procedure and the routines and practices at the surgical department.
Preoperative Fasting
Fasting Before Anesthesia for Planned Surgery
The following time limits apply for oral intake in patients with normal gastric emptying, referring to the time until the start of anesthesia.
- Water (with or without sugar), coffee, tea, clear juice, and special preoperative drink – 2 hours
- Other drinks – 6 hours
- All solid food and semi-solid food – 6 hours
Fasting Before Anesthesia for Emergency Surgery
In principle, the above guidelines also apply to emergency surgical procedures. However, the patient’s condition may sometimes necessitate deviation from these rules. The risk of aspiration must then be weighed against the risk of delaying the procedure.
Note the Increased Risk of Gastric Retention and Aspiration
- diabetes
- mechanical ileus
- intestinal paralysis
- pregnancy
- obesity
- malignancy
- nausea
- hiccups
- anxious and nervous patient
- pain-affected patient
- large food intake
- alcohol-affected patient
Medications to Be Given or Not Given on the Day of Surgery
Recommendations for which regular medications should be taken or discontinued in situations requiring anesthetic intervention to perform surgery, procedure, or examination. The aim is to facilitate the preoperative assessment and make it easier for non-anesthetic staff to follow these recommendations.
Many patients who pass through a surgical department are on regular medication. Regardless of whether it involves general anesthesia, central blocks, regional blocks, or local anesthesia, it is important to know which of the regular medications should be taken or discontinued before surgery, procedure, or examination. The anesthesiologist or anesthetic nurse with delegation for preoperative assessment decides which medications should be taken or discontinued.
The responsible anesthesiologist/nurse should check the medical records to see which medications the patient is taking regularly. It is, of course, important that the patient is informed about which medications should be taken or discontinued. The table below provides a recommendation for the most common medications. However, most patients come in on the morning of surgery, so information on how medications should be taken on the morning of surgery must be provided during the preoperative assessment. It is important to assess whether the patient needs written information.
Medications Normally Given on the Day of Surgery
Betablockers
- Ongoing treatment should be continued perioperatively, in some cases at a reduced dose, e.g., half the normal dose
- Can be initiated in certain patients: high-risk surgery, ≥2 risk factors, known ischemic heart disease.
- Target HR 60-70/min, SBP >100 mmHg
- Atenolol, bisoprolol – titrated to desired effect over 7-30 days preoperatively
- The POISE study showed an increased risk of stroke (bradycardia, hypotension)
Statins (significantly reduce the risk of ischemic events)
- Should be continued perioperatively
- Should be initiated before vascular surgery
- Long-acting preparations, preferably ≥ 2 weeks before surgery
- Rosuvastatin – reduces the risk of CI-AKI
Medications Normally Discontinued
- ACE inhibitors and Angiotensin II antagonists, according to national guidelines, should be discontinued on the day of surgery. Otherwise, there is a risk of severe hypotension that does not respond adequately to adrenergic agonists. Exceptions: Confirmed heart failure and situations where hypertension must absolutely be avoided (e.g., known aortic aneurysm, aortic dissection), as well as poorly controlled malignant hypertension.
- Oral diabetes medications
- Neuroleptic: Clozapine should be discontinued, but consultation with a psychiatrist for perioperative management is recommended. Clozapine has been reported to increase the risk of hypotension, seizures, and paradoxical reaction to adrenaline during anesthesia.
Administration of drugs on the day of surgery
| Drug | Continue | Refrain |
|---|---|---|
| Beta blocker | X | |
| ACE inhibitors | X | |
| Angiotensin II-inhibitors | X | |
| Alpha-2 receptor antagonist | X | |
| Ca flux inhibitors | X | |
| Diuretics (all types) | X | |
| Statines | X | |
| Nitrates, short and long acting | X | |
| Digoxin | X | |
| Inhalation medicine for lung disease (beta stimulantes) | X | |
| Oral diabetes medications | X | |
| Litium | X | |
| SSRI | X | |
| Antipsychotics (dopamine receptor blockers) | X | |
| Clozapine | X | |
| Parkinson's medication | X | |
| Levothyroxine | X | |
| Cortikosteroides | X | |
| Opioides | X |
Preoperative Discontinuation of Anticoagulants
Discontinuation of Anticoagulation Before Spinal Anesthesia
| Medication (Brand name) | Substance | Recommended time from intake of pharmaceuticals to spinal anaesthesia/manipulation | Recommended time from spinal anaesthesia/manipulation to intake of medication |
|---|---|---|---|
| Fragmin ≤ 5000 E Fragmin > 5000 E | Dalteparin | 10 hours 24 hours | 6 hours recommended (2-4 hours usual practice) |
| Arixtra | Fondaparinux | 36 hours | 6 hours |
| Xarelto | Rivaroxaban | 2 days according to SSTHS Clinical Council | 6-24 hours (according to risk) |
| Waran, Coumadin, Jantoven ** | Warfarin | 1-4 days depending on dose | Reinsert after removal of epidural catheter |
| Aspirin, Acetylsalicylic acid Aggrenox, Alka-seltzer, and more | Acetylsalicylic acid | 12 hours in patients with secondary prevention indication 3 days with others | Resume as soon as possible after surgery |
| Voltaren, Aleve Arthritis Pain, Arthrotec, and more | Diclofenac | 12 hours | Should be avoided – COX-2 inhibitors are recommended instead |
| Toradol, Acular, Acuvail, Omidria, and more | Ketorolac | 24 hours | Should be avoided – COX-2 inhibitors are recommended instead |
| Naproxen, Aleve, Naprelan, Naprosyn, and more | Naproxen | 48 hours | Should be avoided – COX-2 inhibitors are recommended instead |
| Plavix, Duoplavin, Zyllt | Clopidogrel | 5 days | After catheter removal |
| Ticlide | Ticlopidine | 5 days | After catheter removal |
| Effient, Efient | Prasurgrel | 7 days according to. SSTHS Clinical Council | After catheter removal |
| Eliquis | Apixaban | 2 days according to. SSTHS Clinical Council | 6-24 hours (according to risk) |
| Pradaxa | Dabigatran | 2 days according to. SSTHS Clinical Council | 6-24 hours (according to risk) |
| Brilinta, Brilique | Tiacagrelor | 5 days | 6 hours |
*NOTE! For patients on new oral anticoagulants/Non-vitamin K antagonist oral anticoagulants (NOACs) (Eliquis, Pradaxa, Xarelto, etc.), clinical guidelines from the Swedish Society for Thrombosis and Hemostasis (SSTH) are recommended and regularly updated.
Anesthesia Methods for Elective Surgical Procedures
| Surgical procedure or Intervention | Airway | Anesthesia model | Epidural / Spinal | Premedication | Remark |
|---|---|---|---|---|---|
| Adrenalectomy open or via laparoscope | Intubation | Sevoflurane/Remifentanil | Epi if open surgery | P +O | |
| If the indication is primary aldosteronism, give oral potassium chloride (KCl) in appropriate dose. Check serum potassium (S-K) the same day | |||||
| Bone marrow aspiration | Sevoflurane/Remifentanil | P+O+COX | |||
| Hernia plastic surgery | Intubation or LM | Sevoflurane/Remifentanil | P+O+COX | ||
| Breast surgery minor | Laryngeal mask | Propofol/Remifentanil or Propofol/Alfentanil | P+O+COX+Bet+ Ond | ||
| Fast track + minor surgery, ASA 1, <65 years, no need for blood sampling (tests, chart review). No opioids for day surgery | |||||
| Breast surgery major | Laryngeal mask | ||||
| Direct reconstruction → PECS block by anesthesiologist before induction | |||||
| Carcinoid surgery | Intubation | Sevoflurane/Fentanyl | Epi if open surgery | P+OXA | |
| ECG, NT-ProBNP. Possibly echocardiography (UCG), watch for carcinoid heart disease | |||||
| Cava thrombosis | Intubation | Sevoflurane/Fentanyl | Epi | P+O | |
| Cholecystectomy open or via laparoscopy | Intubation | Sevoflurane/Remifentanil | Epi if open surgery | P+O+COX | |
| Cystectomy+possible establishment of ileum reservoir | Intubation | Sevoflurane/Fentanyl | Spinal with morphine | P+O | |
| Diagnostic laparoscopy | Intubation | Sevoflurane/Remifentanil | P+O+COX | ||
| Esophagectomy, thoracoabdominal | Intubation | Sevoflurane/remifentanil during the abdominal phase Propofol/remifentanil during the thoracic phase | Epidural anesthesia (Epi) if open surgery | ||
| RSI? DLT. Note: the surgeon must establish an intraoperative substitution plan for oral medications | |||||
| EMR - EUS - ERCP - Gast+ dil | Intubation | Propofol/Remifentanil | |||
| Pheochromocytoma | Intubation | Sevoflurane/Fentanyl | Epi if open surgery | P+O+OXA | |
| Fundoplication - open or via laparoscope | Intubation | Sevoflurane/Remifentanil | Epi if open surgery | P+O | |
| Gastrectomy - ventricular resection | Intubation | Sevoflurane/Fentanyl | Epi | P+O | |
| Gastric pacemaker via laparoscope | Intubation | Sevoflurane/Remifentanil | P+O | ||
| Gastroplasty open or via laparoscope | Intubation | Sevoflurane/Remifentanil | Epi if open surgery | P | |
| Minor neck surgeries (PTH, hemithyr, tot.thyr) | Intubation | Propofol/Remifentanil | P+O+COX+ Bet+Ond | ||
| Note: potentially difficult airway, possibly videolaryngoscope, NIM, avoid neuromuscular blockers (muscle relaxants) | |||||
| Major neck surgeries (sternothomi) | Intubation | Propofol/Remifentanil | P+O | ||
| Note: potentially difficult airway, possibly videolaryngoscope, NIM, avoid neuromuscular blockers (muscle relaxants) | |||||
| Hyperthermic perfusion extremity | Intubation | Sevoflurane/Fentanyl | P+O | ||
| Note: possible immunotherapy, do not give Betametason (corticosteroids), watch for side effects | |||||
| Liver perfusion | Intubation | Sevoflurane/Fentanyl | Epi | O | |
| Liver resection | Intubation | Sevoflurane/Fentanyl | Epi ev | O | |
| Liver transplantion | Intubation | Sevoflurane/Fentanyl | Epi ev | ||
| Nephrectomy/kidney resection | Intubation | Sevoflurane/Fentanyl | Epi | P+O | |
| Kidney donation (living donor) | Intubation | Sevoflurane/Remifentanil | P+O | ||
| Kidney transplantion | Intubation | Sevoflurane/Fentanyl | P+O | ||
| Note gastroparesis – RSI? Monitor plasma potassium (P-K). Preoperative dialysis? Dry weight + chest X-ray if needed. | |||||
| Kidney and auxiliary liver transplantation | Intubation | Sevoflurane/Fentanyl | |||
| Pancreas and kidney transplantation | Intubation | Sevoflurane/Fentanyl | Epi | P+O | |
| Percutaneous stone extraction | Intubation | Sevoflurane/Remifentanil | P+O | ||
| RSI. Note: liquid diet for 5 days and nothing by mouth (NPO) for more than 8 hours. | Intubation | Propofol/Remifentanil | |||
| Splenectomy | Intubation | Sevoflurane/Fentanyl | Epi if open surgery | P+O | |
| Thoraco-abdominal esophageal resection | Intubation | Sevoflurane/Fentanyl Propofol/Remifentanil when using double lumen tube (DLT) | Epi | P+O | |
| Thoracoplasty | Intubation | Propofol/Remifentanil | Epi ev | P+O | Note any other traumatic injuries |
| TUR-B trans urethral resection of bladder tumour | Laryngeal mask | Propofol/Remifentanil | Spinal | P+O | |
| TUR-P trans urethral resection of prostatic tumour | Spontaneous airway | Spinal | P+O | ||
| Ureteroscopy | Laryngeal mask | Propofol/Remifentanil | P+O+COX | ||
| Whipple | Intubation | Sevoflurane/remifentanil | Epidural anesthesia (EDA) | P | |
| Whipple and pancreatic resection | Intubation | Sevoflurane/Remifentanil | Epidural anesthesia (EDA) | P, (O) | |
| Whipple total pancreatectomy, laparoscopy/robot | Intubation | Sevoflurane/remifentanil | Epidural anesthesia (EDA) | P, (O) | |
| Pancreatic resection, distal | Intubation | Sevoflurane/remifentanil | EDA if open | P, (O) | |
VASCULAR SURGERYPreoperative vascular surgical evaluation. NOTE: Antiplatelet therapy is particularly important pre-/perioperatively for certain vascular procedures (and neurointervention). In these cases, any perioperative adjustments (e.g., for regional anesthesia) must always be done in consultation with the operating specialty. |
|||||
| Open aorta | Intubation | Sevoflurane/Fentanyl | P+O | ||
| Echocardiography (UCG) + NT-ProBNP + spirometry. NOTE comorbidities. Dysphagia/contraindication for TEE? | |||||
| EVAR | Intubation | Sevoflurane/remifentanil or Sevoflurane/Fentanyl | P+O | ||
| Lower short-term mortality/morbidity (compared to open). Benefit > risk in elderly with multiple comorbidities? UCG + NT-ProBNP + possible spirometry. Possible sedation in severe comorbidity. | |||||
| EVAR with sedation | Spontaneous breathing | remifentanil or Dexmedetomidine | P+Oxa | ||
| Lower short-term mortality/morbidity (compared to open). Benefit > risk in elderly with multiple comorbidities? UCG + NT-ProBNP + possible spirometry. Possible sedation in severe comorbidity. | |||||
| Carotid | Intubation | Sevoflurane/remifentanil | P+O NT-ProBNP. NOTE BP – side difference? | ||
| Peripheral vascular surgery | Intubation or Sevoflurane/remifentanil or Sevoflurane/Fentanyl | Epidural for major procedures or spinal epidural (SpEDA) | |||
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