Postoperative analgesia in elderly patients.
Elderly people represent the fastest-growing segment of our society and undergo surgery more frequently than other age groups. Effective postoperative analgesia is essential in these patients because inadequate pain control after surgery is associated with adverse outcomes in elderly patients. However, management of postoperative pain in older patients may be complicated by a number of factors, including a higher risk of age- and disease-related changes in physiology and disease-drug and drug-drug interactions. Physiological changes related to aging need to be carefully considered because aging is individualized and progressive. Assessment of pain management needs to include chronological age, biological age with regard to renal, liver and cardiac functions, and the individual profile of pathology and prescribed medications. In addition, ways in which pain should be assessed, particularly in patients with cognitive impairment, must be considered. Cognitively intact older patients can use most commonly used unidimensional pain scales such as the visual analogue scale (VAS), verbal rating scale (VRS), numeric rating scale (NRS) and facial pain scale (FPS). VRS and NRS are the most appropriate pain scales for the elderly. In older patients with mild to moderate cognitive impairment, the VRS is a better tool. For severe cognitively impaired older patients, behavioural scales validated in the postoperative context, such as Doloplus-2 or Algoplus, are appropriate. For postoperative pain treatment, most drugs (e.g. paracetamol, nonsteroidal anti-inflammatory drugs, nefopam, tramadol, codeine, morphine, local anaesthetics), techniques (e.g. intravenous morphine titration, subcutaneous morphine, intravenous or epidural patient-controlled analgesia, intrathecal morphine, peripheral nerve block) and strategies (e.g. anticipated intraoperative analgesia or multimodal analgesia) used for acute pain management can be used in older patients. However, in view of pharmacokinetic and pharmacodynamic changes in older persons, the higher incidence of co-morbidities and concurrent use of other drugs, each must be carefully adjusted to suit each patient. Evaluation of treatment efficacy and incidence and severity of adverse events should be monitored closely, and the concept of 'start low and go slow' should be adopted for most analgesic strategies.