B1. Preoperative patient assessment and risk stratification, preparation for anaesthesia
The preoperative assessment consists of the anaesthesiologist taking history, physical examination, medication history, and assessing comorbidities. It’s usually performed the day before planned surgery. Its purpose is to:
- Provide the patient with through information, which is important for informed consent
- Make the patients to ask questions and receive exhaustive answers
- Reduce the patient’s anxiety, introduce yourself
- Allow the anaesthesiologist to familiarize themselves with:
- The patient’s medical history, social history (smoking, drinking)
- The patient’s reactions to the previous anaesthesiologic procedures
- The patient’s symptoms
- Allow the anaesthesiologist to thoroughly assess the risks of anaesthesia
- To make suggestions for preoperative diagnostics and/or therapy
- To prepare the best possible anaesthesia plan
Sometimes, special tests are necessary, like pulmonary function test in case of severe respiratory disease (COPD, untreated asthma) or chest surgery. Tests are generally only performed if the result will affect the anaesthesia plan.
Preoperative risk stratification (ASA)
ASA (American Society of Anaesthesiologists) categories are used to categorise patients according to their physical status:
- ASA 1 – healthy, non-smoking patient
- ASA 2 – patient with well-controlled disease with normal quality of life
- Overweight, well-treated hypertension
- ASA 3 – patient with disease which impacts normal functioning of patient
- Poorly treated DM, stable angina
- ASA 4 – unstable patient with disease is a constant threat to life
- ASA 5 – patient unlikely to survive for > 24 hours without surgery
- Ruptured AAA, polytrauma
- ASA 6 – brain dead patient
Preparation for anaesthesia
Certain drugs must be stopped before surgery:
- Smoking – 24 hours before
- RAAS inhibitors – 1 day before
- Warfarin – INR should be < 1,3
- DOAC – 2 days before
- Metformin – 2 days before
- Antiplatelets – 7 days before
The patient must also stop eating the night before or at the latest 6 hours before, and no liquids at all in the last 2 – 4 hours.
In some cases, premedication is necessary:
- Benzodiazepines for anxiety
- Antiemetics for nausea
- Analgesics
- Antibiotic prophylaxis
In cases of low-risk (ASA 1 or 2) patients undergoing small surgical procedures, day-case surgery is an option. This decreases the hospital stay, is cheaper and has lower risk for nosocomial complications.