Audit of peripheral neuromuscular stimulators at the hospitals staffed by the Department of Anaesthesia and Perioperative Medicine at the University of Cape Town

Abstract

Background: Inadequate monitoring of neuromuscular blockade (NMB) may result in worse patient outcomes, including airway compromise and postoperative pulmonary complications. Therefore, NMB monitor availability is a minimum requirement for perioperative care according to the South African Society of Anaesthesiologists’ (SASA) 2018 guidelines. The authors performed an audit of peripheral nerve stimulators (PNS) functionality and availability at their institution.
Methods: The PNSs were attached to an electrical circuit with a skin equivalent resistance. The resultant current impulses generated using Train-of-Four (TOF) mode and Double Burst Stimulation (DBS) mode were recorded with a voltage scope meter. PNS availability was assessed in theatre and recovery areas.
Results: Of the 65 PNS units assessed, 39 units were dysfunctional and 26 units fully functional. The most frequent fault found (30 units) related to faulty or absent PNS electrode cables. Eight functional PNS units with TOF ratio display capability were found. The working PNSs showed good inter-device peak voltage measurement correlation. Of the 59 areas identified where PNSs should be easily available, only 37 areas met the PNS availability criteria suggested in the SASA guidelines.
Conclusion: This audit highlighted the need for more new generation PNSs with TOF-ratio-display-ability to align the institution with recommendations from SASA standards and the anaesthetic literature. It also highlighted the accuracy and consistency of delivered current bursts by the working PNS devices.