The Utility of Active Electrode Monitoring Systems for Detecting Insulation Failures in Laparoscopic Instruments

Yusuke Watanabe, MD1, Amin Madani, MD2, Yo Kurashima, MD, PhD1, Mikiya Takeuchi, MD, PhD3, Toshiaki Shichinohe, MD, PhD1, Satoshi Hirano, MD, PhD1. 1Department of Gastroenterological Surgery II, Hokkaido University Graduate School of Medicine, 2Department of Surgery, McGill University Health Centre, 3Department of Gastroenterological Surgery, Sapporo Kyoritsu Gorinbashi Hospital

Introduction: Insulation failure with laparoscopic instruments is a rare but serious source of intra-operative complications arising from the use of electrosurgery caused by current diversion. Breaks in insulation are often not visible by visual inspection alone and active electrode monitors (AEM) have been advocated as the gold standard for their detection. Yet, there is limited evidence to demonstrate the usability and added value of AEMs. The purpose of this study was to evaluate the accuracy of visual inspection and to compare inter-rater reliability between visual inspection and AEM for detecting insulation failure in laparoscopic instruments, and to determine the usability of an AEM system.

Methods: All laparoscopic reusable insulated instruments at a single community hospital were evaluated for insulation failure using both visual inspection and an AEM system (InsluScanTM) by three operating room nurses and one surgical sterilization technician who regularly inspect laparoscopic instruments prior to use. Using AEM as the gold standard, the sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), and accuracy of visual inspection for detecting insulation breaks were calculated. Inter-rater reliability of visual and AEM inspection were calculated using Cohen’s Kappa statistic. Subjects also completed a System Usability Scale (SUS) questionnaire for the AEM (score range 0 to 100) to assess its usability. Data was expressed as median [interquartile range].

Results: A total of 20 laparoscopic instruments were tested independently by all four subjects (median work experience 7.5 [3.8-9] years). Median total inspection time was similar between visual and AEM assessments (6.0 [4.1-8.3] and 6.5 [5.4-7.0] minutes, p=0.67). Median number of instruments falsely labeled as suspicious of insulation failure during visual inspection was 3 [3-4] per subject, while all 4 subjects failed to visually identify one instrument (5%) with confirmed insulation failure using AEM (sensitivity=0.00; specificity=0.80; PPV=0.00; NPV=0.94; accuracy 0.76). Inter-rater reliability was 0.60 and 1.00 for visual inspection and AEM, respectively. The SUS questionnaire score for the AEM system was 89 [79-98], with most subjects reporting ease of use and a lack of complexity or need for additional training or technical support.

Conclusions: Visual inspection is suboptimal to detect insulation failure for minimally-invasive surgical instruments and can result in unintended current diversion and subsequent injury when using electrosurgery. An AEM system is significantly more reliable, and seems to be a feasible system for widespread implementation as a quality-improvement initiative to contribute to safer surgery.

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