key: cord-0831131-d9dnugod
authors: Ali Hassan, Syed M.; Palacios, Camila Mayorga; Ethier, Tarrah; Bisleri, Gianluigi
title: Improved safety of endoscopic vessel harvesting during the COVID-19 pandemic
date: 2020-06-03
journal: Ann Thorac Surg
DOI: 10.1016/j.athoracsur.2020.05.016
sha: da3e13409978df9127a440fcee7d2c65c4d2fa3b
doc_id: 831131
cord_uid: d9dnugod

Abstract The COVID-19 pandemic has necessitated that operating room procedures be modified to ensure the safety of staff and patients. Specifically, procedures that have the potential to create aerosolization must be reassessed, given the risk of viral transmission via aerosolization. We present the use of a non-sealed endoscopic vessel harvesting(EVH) approach during coronary surgery that does not necessitate the use of CO2 insufflation and utilizes suction through an ultra low particulate filter, thus mitigating the risk of possible viral transmission via aerosolization or surgical smoke production. This approach is technically feasible and can minimize the risk of viral transmission during EVH.

The COVID-19 pandemic has necessitated that operating room procedures be modified to ensure the safety of staff and patients. Specifically, procedures that have the potential to create aerosolization must be reassessed, given the risk of viral transmission via aerosolization. We present the use of a non-sealed endoscopic vessel harvesting(EVH) approach during coronary surgery that does not necessitate the use of CO2 insufflation and utilizes suction through an ultra low particulate filter, thus mitigating the risk of possible viral transmission via aerosolization or surgical smoke production. This approach is technically feasible and can minimize the risk of viral transmission during EVH.

The COVID-19 pandemic has necessitated that operating room procedures be modified to ensure the safety of staff and patients. Specifically, procedures that have the potential to create aerosolization have to be reassessed, given the risk of viral transmission during such procedures [1] [2] [3] . The sensitivity of reverse transcriptase polymerase chain reaction for COVID-19 testing is as high as 90 %; however, that means that at least 10% of patients have false negative results [4] .

Therefore, even when a patient has tested negative, appropriate precautions need to be maintained especially in an operating room environment where certain procedures are at risk of creating aerosol. The risk of viral spread through aerosolized gas during endoscopic surgery is a theoretical one; however, previous studies have shown that viruses have the potential to be carried in both surgical smoke and aerosolized gas [5, 6] . While its transmission via this method is not fully understood, COVID-19 presents a novel risk for which precautions must be taken if possible and where feasible. To date, the most adopted method for EVH has been based on a sealed approach which utilizes an active insufflation of CO2, thereby potentially exposing operators to an increase risk of infection. We present the use of a non-sealed endoscopic vessel harvesting (EVH) approach during coronary artery bypass (CABG) surgery that does not necessitate the use of CO2 insufflation and thus mitigates the risk of possible viral aerosolization.

Since March 18 th 2020, 28 consecutive patients underwent coronary artery bypass grafting with a non-sealed endoscopic approach for conduit harvesting at the Kingston Health Sciences Centre (KHSC). The mean age of these patients was 70 ±7 years, with 7 (25%) female, dyslipidemia. Of these, 23 patients underwent endoscopic harvesting of the great saphenous vein and 5 underwent endoscopic radial artery harvesting. These patients had been admitted to KHSC after the COVID-19 emergency had been declared in Ontario. Assuming universal precautions, especially given the risks of asymptomatic viral transmission, it was decided that a non-sealed approach for EVH would be utilized to minimize the risks of aerosolization that could potentially occur with CO2 insufflation. (Video 1, Fig. 1 ). The Ligasure device creates minimal smoke which is removed using a suction device that is attached to the retractor and connected to an ultra low particulate air filter (CONMED, NY, USA) which can remove particles as small as 0.1-0.2 micron in size. The filter setting is kept at low to reduce obstruction of the camera view due to excessive suction of the tissue towards it. This is sufficient to remove the small amount of smoke that might be generated. The vein is harvested to a length of 20-25 cm up to the thigh and a curved pigtail vessel dissector (Hook Dissector, Karl Storz, Tuttlingen, Germany) is used to assess complete mobilization of the conduit. The vein is then proximally incised and retrieved. A similar harvesting technique is utilized for the radial artery while maintaining a dissection plane between the brachioradialis muscle and the flexor carpi radialis and taking care not to damage the radial nerve (Video 2). Both the radial artery and vein harvesting are performed as a no touch technique. All patients had an uneventful hospital stay and were discharged after a post operative stay of 5.4 ± 2 days.

We present the use of a non-sealed endoscopic vessel harvesting approach during CABG surgery that does not necessitate the use of CO2 insufflation and thus mitigates the risk of possible viral aerosolization. It is important to note that, given the risk of asymptomatic transmission and the 10% chance of false negatives [4] , it is imperative that universal precautions be taken for all cardiac surgery patients [1] . While the risks of COVID-19 transmission via smoke production and aerosolization due to CO2 insufflation have yet to be fully elucidated, previous studies have shown the presence of hepatitis B virus in surgical smoke plumes [5] . The novel risk that COVID-19 poses merits a reduction in risk wherever possible and thus the non-sealed approach for EVH is a viable option in this regard. Moreover, the non-sealed approach may reduce the risk of vein graft thrombosis that may occur due to over distension during CO2 insufflation [7] . Finally, it should be noted that this approach allows for a pedicled harvest technique of the saphenous vein which has been associated with better long term patency [8] . Given the technical feasibility of the non-sealed approach for EVH for both the saphenous vein and radial artery and since there is no risk of aerosolization due to CO2 insufflation, this approach can be utilized in the COVID era to further minimize risks of viral transmission during EVH for coronary surgery.

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