Frequency of inadequate neuromuscular blockade during general anesthesia

We used electronic health record data to define frequency of inadequate intraoperative neuromuscular blockade (NMB).

Retrospective observational study using electronic health record data.

Operating room in a tertiary care academic hospital.

A total of 129,209 adult patients with American Society of Anesthesiologists physical status 1 to 5 undergoing general anesthesia in an outpatient or inpatient setting who received nondepolarizing NMB. We excluded patients intubated before arrival to the operating room, patients undergoing a liver transplant or cardiac surgery, and patients who remained intubated at the end of the operation.

None.

The primary outcomes were inadequate NMB defined by (1) documentation of patient movement and (2) documentation of surgical request for additional NMB, followed by NMB agent administration.

A total of 1261 patients (1.0%) demonstrated either intraoperative movement (369 or 0.29%) or prompted surgical request for additional NMB agent (921 or 0.71%). Trend analysis showed a variation in the annual rate of inadequate NMB, with an increase from 2004 to 2013 for criteria 1 and 2.

Nearly 1% of all general anesthetic procedures involving NMB exhibit inadequate relaxation resulting in procedural interruption. These data suggest that current use of neuromuscular blocking drugs and NMB monitoring expose patients to inadequate blockade. The risk of this phenomenon warrants further study.