The Thai Anesthesia Incident Monitoring Study (Thai AIMS) of anesthetic equipment failure/malfunction: an analysis of 1996 incident reports.

BACKGROUND: The present study is a part of the multi-centered study of model of anesthesia relating adverse events in Thailand by incident report (The Thai Anesthesia Incident Monitoring Study or Thai AIMS). The objective was to identify the frequency distribution, contributing factors, and factors minimizing incident of equipment failure/malfunction.

MATERIAL AND METHOD: As a prospective descriptive research design, anesthesia providers reported the data as soon as the incidents of equipment failure/malfunction occurred. Standardized forms of incident report were then mailed to the center at Chulalongkorn University and three anesthesiologists reviewed the data.

RESULTS: Ninety-two cases of equipment failure/malfunction were reported from 51 hospitals across Thailand Between January and June 2007, 92 incidents of equipment failure/malfunction were reported out of 1996 anesthesia-related incidents (4.6%). Failed/malfunctioned equipment included anesthetic circuit (17.4%), anesthesia machine (15.2%), capnography (15.2%), laryngoscope (15.2%), ventilator (12%), pulse oximeter (8.7%), vaporizer (4.3%), endotracheal tube (3.3%), sodalime (3.3%), and electrocardiogram (2.2%). All 16 anesthetic circuit incidents (100%) were detected by clinical signs whereas five incidents (31.3%) were detected firstly by monitors. All 14 laryngoscope malfunction (100%) were detected solely by clinical signs. Only one out of eight (12.5%) of pulse oximeter incidents was detected by clinical signs before the pulse oximeter itself. Three out of four (75%) incidents of vaporizer were detected by clinical signs before monitors. The majority of equipment malfunction was considered as related to anesthetic (69.6%) and system factors (69.6%) and 71.7% of incidents were preventable. Seventy-four incidents (80.4%) were caused by human error and, specifically, rule-based error in three fourths.

CONCLUSION: Contributing factors were ineffective equipment, haste, lack of experience, ineffective monitors, and inadequate equipment. Factors minimizing incidents were equipment maintenance, pre-use equipment checking, vigilance, prior experience, and compliance to guidelines. Suggested strategies were quality assurance activity, training, and improvement of supervision.