Effect of age on acute pain perception of a standardized stimulus in the emergency department

Study objective: The study was undertaken to determine whether pain perception is different in elderly patients than in younger patients. Methods: A cross-sectional, observational study was conducted at 2 urban academic emergency departments. Adult patients (≥18 years of age) who required an 18-gauge intravenous catheter as part of their ED care were eligible. Patients were excluded for the following conditions: more than one attempt at intravenous catheter placement, altered mental status, visual impairment, intoxication, distracting pain, or abnormal upper extremities. Patients were asked to indicate on a 10-cm visual analog scale (VAS) the amount of pain they had at baseline immediately before intravenous catheter placement. They were then asked to indicate on a separate VAS the amount of pain caused by intravenous catheter placement. Patients aged 65 years and older were defined a priori as elderly. Results: Of 100 patients enrolled in the study, 32 (32%) were elderly. Elderly patients reported significantly less pain than nonelderly patients (δ=-15 mm, 95% confidence interval -26 to -4 mm). Pain of intravenous catheter placement was not associated with sex, baseline pain, site of intravenous catheter insertion, or level of training of the individual placing the intravenous catheter. Conclusion: Elderly patients experienced less acute pain than their younger counterparts in response to a standardized stimulus in a clinical setting. This difference is both statistically and clinically significant. This may have clinical implications for the assessment and treatment of acute pain in the elderly.