Differences in the Effectiveness of Smoke Evacuator Types for Reducing Surgical Smoke: A Randomized Controlled Trial

Surgical smoke contains respirable particles and volatile organic compounds (VOCs) associated with carcinogenic and infectious risks to operating room personnel. Whether electrocautery-incorporated smoke evacuation improves particulate and VOC clearance compared with hose-type evacuation remains undefined.

In this randomized, double-blind clinical trial (UMIN000047033) conducted from February 2022 to May 2023 at The University of Tokyo Hospital, 64 patients undergoing laparotomy were assigned 1:1:1 to electrocautery-incorporated evacuation with an 8 mm tip distance (n = 22), 18 mm tip distance (n = 23), or hose-type evacuation (n = 21). The primary endpoint was the change in particle counts at 0.3, 0.5, 1.0, and 5.0 μm during a standardized 10-minute sampling period. Secondary endpoints were acetaldehyde and formaldehyde levels. Comparisons used the Wilcoxon rank-sum testing with Bonferroni correction.

The 8 mm electrocautery-incorporated system reduced particle counts by 96% to 97% across 0.3 to 5.0 μm compared with hose-type evacuation (all p < 0.05). The 18 mm system reduced 0.3 μm particles by 78% vs hose (p = 0.005), with 81% to 88% reductions for 0.5 to 5.0 μm particles (p > 0.05). Median (interquartile range) acetaldehyde levels were 1.90 (1.10 to 2.50), 2.70 (0.50 to 4.00), and 7.90 (3.10 to 15.20) μg/m3 in the 8 mm, 18 mm, and hose groups, respectively; both electrocautery groups were lower than hose (all p < 0.05). Formaldehyde levels were similarly reduced (all p < 0.05).

Electrocautery-incorporated smoke evacuation significantly reduced respirable particle and VOC exposure compared with hose-type evacuation, with maximal particulate reduction at an 8 mm tip distance. Device selection and proximity to the cautery source materially influence operating room exposure to surgical smoke.