General patient assessment
The overall aim of patient assessment is to ensure that surgery is justified and that the risks to the patient from the procedure are minimised, especially in patients at high risk of surgical complications. Therefore, one of the most important considerations prior to surgery is the condition of the patient. This will determine the pre-operative precautions and medication required, as well as the choice of anaesthetic and operative technique. These decisions can be made in collaboration with the patient’s primary care physician, or within specialist pre-operative assessment clinics. Information resources such as postoperative pain guidelines may be useful: http://www.healthquality.va.gov/Post_Operative_Pain_Management_POP.asp(Rosenquist 2003) and http://www.nhmrc.gov.au/_files_nhmrc/file/publications/synopses/cp104.pdf (Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine) The approach to optimising pre-operative patient health prior to surgery varies between surgical procedure and between different hospitals, but some basic principles apply to all patients undergoing surgery:
- Diabetes mellitus should be stabilised using the most appropriate oral medication or insulin-replacement regimen. The patient may need to be hospitalised early in order to commence a sliding-scale insulin regimen for the peri-operative period
- Patients with cardiovascular and respiratory disorders will also benefit from pre-operative management, to ensure that they are in optimum medical condition during surgery
- Conventional non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed for controlling pain and – although effective – can have significant adverse effects on renal, haematological and gastrointestinal function (see Systemic analgesia, Conventional NSAIDs, Transferable evidence). They can be continued up to 48 hours before surgery and can then be stopped and replaced with alternative analgesic medications until the risk of impaired haemostasis has diminished in the postoperative period. Any elderly patient on long-term conventional NSAIDs should have their renal function assessed and be questioned on their history of gastrointestinal symptoms. The effects of conventional NSAIDs on clotting function should also be assessed, especially if the patient also takes other drugs that affect clotting (e.g. aspirin, clopidogrel or low molecular weight heparins for thromboprophylaxis).
- Studies in healthy volunteers have shown that the COX-2-selective inhibitors have no adverse effects on platelet aggregation (Greenberg 2000, Leese 2000, Leese 2002b, Noveck 2004, Noveck 2001, Wilner 2002) or bleeding time (Leese 2000, Leese 2002b, Noveck 2001) compared with placebo (see also Systemic analgesia, COX-2-selective inhibitors, Transferable evidence). Therefore, COX-2-selective inhibitors may have a role in treating patients who traditionally have been prescribed conventional NSAIDs. The decision about which anaesthetic technique to use for an individual patient is based on a formal review of their overall medical condition and any medication that they are taking. General, epidural and spinal anaesthesia, and combinations of these, have separate risks and benefits, which vary according to the patient’s co-morbidity and medications. Other factors such as surgical and anaesthetic experience and practice, local ward or institutional protocols for postoperative pain relief and patient mobilisation will also influence the choice of anaesthetic technique. In addition to the choice of anaesthetic, there are also some general surgical considerations:
- Pre- and intra-operatively, the responsible surgeon – in cooperation with the anaesthesiologist – should decide whether to use a ‘cell-saver’ to re-use the patient’s own erythrocytes, where this is required
- It is important to evaluate the pre-operative ‘activities of daily living’ and ‘biological age’ of the individual patient, as these can both affect the choice of surgical technique