Relationship Between Age and Frequency of Side Effects Associated with Postoperative Analgesia

Study Objective: Although patient-controlled analgesia (PCA) is a valid analgesic method, it is necessary to pay attention to associated side effects, especially in elderly patients. It is unclear whether the incidence of side effects increases with age. In this study, we examined the incidence of side effects by age to confirm whether the frequency of side effects varies depending on age group.
Patients: Patients who underwent gastroenterological surgery at Hiroshima University Hospital between 2009 and 2013 and received postoperative analgesia using PCA [either epidural PCA (PCEA) or intravenous PCA (IVPCA) were included].
Measurements: The degree of pain using the visual analog scale, number of PCA requests, and frequency of side effects, including nausea, vomiting, pruritus, urinary disturbance, drowsiness, low blood pressure, delirium, and respiratory depression, was determined from PCA records.
Main Results: A total of 2,881 patients were enrolled and categorized into PCEA (n = 1,965) or IVPCA (n = 916) group based on postoperative analgesia. The incidence of delirium significantly increased with age in both groups (P < 0.001). In the PCEA group, the incidence of nausea, vomiting, and itching decreased, whereas that of hypotension significantly increased with age. Visual analog scale scores both at rest and during activity on postoperative day 2 were not correlated with age in either group. There was a significant negative correlation with age in both groups for the number of PCA requests on postoperative day 2.
Conclusions: The incidence of postoperative delirium increases with age regardless of pain relief method. Side effects related to postoperative analgesia are not necessarily more likely to occur with age.