General Anaesthesia - Postoperative Care

Postoperative Care

The anaesthesia should conclude with a pain-free awakening and a management plan for postoperative pain relief. This may be in the form of regional analgesia, oral, transdermal, or parenteral medication. Minor surgical procedures are amenable to oral pain relief medications such as paracetamol and NSAIDs such as ibuprofen. Moderate levels of pain require the addition of mild opiates such as tramadol. Major surgical procedures may require a combination of modalities to confer adequate pain relief. Parenteral methods include patient-controlled analgesia (PCA) involving a strong opiate such as morphine, fentanyl, or oxycodone. Here, to activate a syringe device, the patient presses a button and receives a preset dose or "bolus" of the drug (e.g., one milligram of morphine). The PCA device then "locks out" for a preset period, e.g. 5 minutes, to allow the drug to take effect. If the patient becomes too sleepy or sedated, he or she make no more morphine requests. This confers a fail-safe aspect that is lacking in continuous-opiate infusion techniques. Postanesthetic shivering is a frequent occurrence in the post-operative period. Apart from causing discomfort and exacerbating post-operative pain, shivering has been shown to increase oxygen consumption, catecholamine release, cardiac output, heart rate, blood pressure, and intra-ocular pressure. There are a number of techniques used to reduce this occurrence, such as increasing the ambient temperature in theatre, using conventional or forced warm air blankets, and using warmed intravenous fluids.

In many cases, opioids used in general anaesthesia can cause post-operative ileus even in non-abdominal surgery. Administration of a μ-opioid antagonist such as alvimopan immediately after recovery can help reduce the severity and duration of ileus.