Preoperative assessment
Introduction
For elective treatment, clerking is often performed at a pre-assessment visit by a junior doctor or a surgical or anaesthetic assistant. This is to anticipate potential medical and social complications, and take preventive action (Box 7.1). In patients with significant co-morbidity, a senior anaesthetist (anaesthesiologist) should also make an assessment. This is often performed in specialised clinics, which increasingly have direct access to advanced assessment tools such as cardiopulmonary exercise testing and pulmonary function analysis.
Principles of preoperative assessment
The essence is careful questioning and examining to foresee anaesthetic and surgical problems, plus any social aspects relevant to the admission. Most surgical cases are uncomplicated but preventable disasters occur unless the approach is systematic. The patient’s condition may need optimising, taking the urgency of surgery into account. The assessor aims to answer the questions in Box 7.1. The review may disclose the need for tests or other actions and also identifies patients with medical co-morbidity who have risks of particular perioperative problems. Current treatment of co-morbidity (e.g. diabetes, hypertension) also needs review. Investigations provide baseline information against which later changes can be measured, e.g. echocardiography in heart failure. Common problems of high-risk groups are summarised in Table 7.1.
Table 7.1
High-risk groups for perioperative complications
Group | Particular risks | Management |
Premature or tiny babies, neonates and infants | Fluid and electrolyte lossHeat loss in operating theatre | Careful measurement and replacement of fluids and electrolytesWarming blanket, temperature monitoring |
Patients over 60 | Cardiovascular disease | Chest X-ray and ECG preoperatively if indicated by guidelines, and monitoring during operation |
Very elderly patients | ConfusionHyponatraemiaImmobility | Multifactorial—see Chapter 8Preoperative electrolyte estimations and correctionGood nursing and rehabilitation |
Smokers | Postoperative chest infection and atelectasisIncreased risk of myocardial infarction | Stop smoking before operation—ideally at least 4 weeks beforehandPreoperative chest X-rayPreoperative and postoperative physiotherapyPreoperative ECG; avoid hypoxia during and after operation; postoperative oxygen therapy |
Obese patients | Increased risk of DVTIncreased risk of wound infectionReduced mobility | DVT prophylaxis—see Chapter 12Preoperative counselling during consent processEarly mobilisation with assistanceEncourage patients to lose weight prior to surgery |
Patients with intercurrent medical disease | Depends on medical condition | Early referral to anaesthetist and/or medical specialist |
Essentials of preoperative assessment
Standard preoperative procedures vary in different hospitals but basic steps ensure the greatest patient safety (see Box 7.2). The nature and urgency of the operation and the state of the patient determine what is needed.