Intraoperative anaphylaxis to neuromuscular blocking agents: the incidence over 9 years at two tertiary hospitals in South Korea: A retrospective observational study.

BACKGROUND: Intraoperative anaphylaxis to neuromuscular blocking agents (NMBAs) is a rare event that is unpredictable and potentially life threatening. Most of the previous reports on such intraoperative anaphylaxis used market share surveys or self-reported data to estimate the incidence. OBJECTIVE: To determine the incidences of intraoperative anaphylaxis to NMBAs using electronic medical records. DESIGN: A retrospective observational study. SETTING: Two tertiary hospitals in South Korea. PATIENTS: This study involved patients exposed to NMBAs during anaesthesia between 1 January 2005 and 31 May 2014. Nineteen episodes were deemed to be intraoperative anaphylaxis to NMBAs. MAIN OUTCOME MEASURES: We calculated the incidences of intraoperative anaphylaxis to NMBAs. Exposure to the agents was determined from intraoperative records maintained in an electronic medical recording system. An anaphylactic reaction was determined from both clinical signs and the results of skin tests. RESULTS: Over 9 years, 729 429 patients were exposed to NMBA, the most frequently used being rocuronium [425 047 (58.3%)] and vecuronium [274 801 (37.7%)]. The overall incidence of intraoperative anaphylaxis was 2.6 per 100 000 (19 cases), and was higher with rocuronium (16 cases, 3.8 per 100 000) than with vecuronium (two cases, 0.7 cases per 100 000), P = 0.014. Comparing the first 3 years with the last 6 years, the incidence of intraoperative rocuronium anaphylaxis appeared to increase 1.4-fold (P = 0.006). CONCLUSION: Among commonly used NMBAs, rocuronium appears to have the highest incidence of anaphylaxis. Our findings suggest that future prospective investigation for NMBA-induced anaphylaxis should use internationally agreed skin test protocols.

The head-down tilt position decreases vasopressor requirement during hypotension following induction of anaesthesia in patients undergoing elective coronary artery bypass graft and valvular heart surgeries.

BACKGROUND AND OBJECTIVE: Previous studies have failed to demonstrate that the head-down tilt position confers benefits in hypovolaemic hypotensive patients. The aim of this study was to evaluate the haemodynamic effect and vasopressor use by this position in hypotensive patients after the induction of general anaesthesia. METHODS: This prospective randomised study involved 98 patients scheduled for elective cardiac surgery and 40 patients (40.1%) developed hypotension after anaesthesia induction. Upon occurrence of hypotension, patients were randomly allocated to the supine (n = 19) or head-down tilt (n = 21) groups (15° head-down tilt position). Blood pressure, heart rate, cardiac index and stroke volume index were recorded at 1-min interval for 10 min from the occurrence of hypotension. Vasopressors were administered to treat hypotension in both groups. RESULTS: No haemodynamic difference was observed between the supine and head-down tilt groups except for SBP changes from baseline at 1 min (-3.98 ± 6.31 vs. 1.84 ± 8.25%, P = 0.004) and 2 min (1.51 ± 14.34 vs. 9.37 ± 10.57%, P = 0.032). The number of vasopressor administrations and percentage of the patients requiring vasopressors in the supine group were greater than that in the head-down tilt group [median 1 (range 1-5) vs. median 0 (range 0-2), P = 0.002, 19/19 (100%) vs. 10/21 (47.6%), P < 0.001]. CONCLUSION: The head-down tilt position in hypotensive patients following anaesthesia induction reduced vasopressor requirement by almost one third. Minimal haemodynamic effect may be caused by different vasopressor administrations. This result suggests that the head-down tilt position may enable more stable anaesthesia induction in patients undergoing elective coronary artery bypass graft or valvular heart surgeries.