A CFD Analysis of Gas Leaks and Aerosol Transport in Laparoscopic Surgery

Abstract

Gas used to distend the abdomen during laparoscopic surgery is released to the external environment when trocar internal valves are opened during instrumentation. Particulate matter, including smoke pollutants and both biological and microbial materials, may be transported within the leakage gas. Here, we quantify the percentage of particulate matter that escape to the airspace and put surgical staff at risk of inhalation using a high-fidelity computational fluid dynamics model, validated with direct Schlieren observation of surgery on a porcine cadaver, to model the gas leak occurring due to the opening of 12 mm trocar valves around insertion/extraction of a 5 mm laparoscopic instrument. Fluid flow was modeled through the internal double-valved geometry of the trocar to a large external region representing the operating room (OR) space. Aerosol particles in the range 0.3–10 μm were injected into the simulation. A range of intra-abdominal pressures (IAPs) and leakage durations were studied. For gas leak durations of 0.5–1 s, at least 65% of particles reach the surgical team's breathing zone across all IAPs. A typical leak had an estimated volume of 0.476 l of CO2 meaning for a typical laparoscopic operation (averaging 51 instrument exchanges), and 24.3 l escapes via this mechanism alone. Trocar gas-leak emissions propel considerable gas and particle volumes into the OR. Reducing the IAP does not mitigate their long-range travel. This work indicates the potential for powerful computational tools like large eddy simulation to play an impactful role in the design of medical devices such as surgical trocars where complex gas dynamics occur.