Opioid analgesia and assessment of the sonographic Murphy sign

Administration of intravenous opioid analgesia to patients with undifferentiated abdominal pain remains a controversial topic in many emergency departments. To determine whether opioid analgesia impacts assessment of the sonographic Murphy sign (SM) in evaluating acute gallbladder disease (GBD), a retrospective chart review was undertaken. The chart review encompassed 119 patients, 21% of whom, having received opioid analgesia before ultrasound, constituted the opioid group. Between the opioid and control (i.e., no opioid analgesia) groups, there were no significant differences in SM sensitivity (48.2%; CI 28.7-68.1% vs. 68.8%; CI 41.3-89%, respectively) or specificity (92.5%; CI 83.4-97.5% vs. 88.9%; CI 51.8-99.7%, respectively) for GBD. There was no association between opioid analgesia and false-positive SM (OR 0.74, CI 0.08-6.65), or false-negative SM (OR 1.42, CI 0.46-4.43). We conclude that the test characteristics of SM are unaffected by opioid analgesia.