Pain and its relief

Overview:

Surgical intervention almost always causes pain. As it can have serious physiological and psychological consequences, prevention is best, but if that cannot be completely achieved, rapid and adequate relief is essential. The intensity of postoperative pain that is perceived by the patient is influenced by:

• Cultural and family background, upbringing, personality ,constitution, past experiences and motivation
• Amount of information provided preoperatively – the more the better is a good guide
• Psychological factors which are often situation-specific, such as emotional arousal and fear; a calm reassuring attitude from the team is of great value and is helped by close interpersonal relations with the patient
• Preoperative and postoperative support provided by the whole team, which includes nurses and physiotherapists

Effects of postoperative pain:

Effect Outcome

Decreased respiratory excursion Hypoventilation

Pulmonary collapse/consolidation

GI atony Ileus, nausea/vomiting

Bladder atony Urinary retention

Catecholamine release Vasoconstriction, increased blood viscosity, increased platelet aggregation, increased cardiac demands

Management:

• Management has increasingly become a specialised province of either the anaesthetist or a pain management team

Prevention:

A caring, sympathetic and informative approach by the team does much to reduce the patient’s perception of pain, as does assurance that any pain felt will be relieved at once. Physical methods for preventing pain include:

• Gentle surgical technique with minimal tissue damage
• Adequate immobilisation of areas that have been operated when this is possible – limbs in particular and after orthopaedic procedures
• Blockade of nerve impulses which may be achieved at a number of sites on the afferent pathway

Therapy:

All agents are better given on a regular basis rather than withheld until relief is asked for

NSAIDs, aspirin and Paracetamol:

• Are often sufficient for mild postoperative pain provided the patient can swallow

Narcotic (opioid) analgesics:

• Have long been the main agents used to counteract postoperative pain
• Morphine sulphate remains the drug most widely used
• Immediately after the operation, they are given by the parenteral route (IM or IV)
• It is now common for continuous infusion to be used so that saturation of the opioid receptors in the brain is achieved