The risk of transmission of COVID-19 during laparoscopy

It is known that the first step in any minimally-invasive procedure is to establish CO² pneumopertionium under pressure that usually ranges from 8 to 15 mmHg. This step may be associated with the risk of exposure of the operating team and theatre to aerosol, and in patients with COVID-19 it would be contaminated and potentially infectious aerosol [4]. Furthermore, the use of energy devices and electrocautery generates a considerable amount of smoke of low temperature that cannot deactivate the virus components efficiently [4]. Indeed, a recent case report [5] showed that the viral load of SARS-CoV-2 in the peritoneal fluid was higher compared to the upper respiratory material, which suggests a possible risk of infection at the operation. However, since isolation of SARS-COV-2 from the peritoneal fluid was not performed, future studies aiming to isolate and culture the virus would provide stronger evidence of infectivity.

A recent experimental study [6] in the New England Journal of Medicine (NEJM) assessed the stability of SARS-COV-2, the causative organism of COVID-19, in aerosols and on various surfaces. The study came to a conclusion that the virus remained viable in aerosols for up to three hours, with a reduction in infectious titer from 103.5 to 102.7 TCID50 per liter of air. Airborne transmission of SARS-COV2 was then presumed a possible occurrence.

Another study [7] examined air and surface samples of 13 COVID-19 positive patients for viral shedding. Many commonly used items and air samples had evidence of viral contamination, indicating that SARS-CoV-2 is shed to the environment as expired particles. The study concluded that the methods of transmission of the disease include droplet, person-to-person contact, indirect contact with contaminated objects, and airborne transmission.

Li et al. [8] reported that the particle concentration of smoke in laparoscopic surgery was significantly higher than in open surgery after 10-minute usage of electrical or energy devices. One explanation of this finding was the low mobility of gas in the established pneumoperitoneum, permitting the generated aerosol to concentrate in the abdominal cavity.

Exposure of the operating staff to COVID-19 can occur via different mechanisms and in many circumstances that comprise sudden release of trocar valves, exchange of instruments, and during extraction of specimens form the incision site. Even if direct exposure of the operating staff to the potentially infectious aerosol did not occur, indirect transmission of infection may still be possible by contact with surfaces, objects, and contaminated objects in the operating room that got contaminated with infectious aerosol [4]. While personal protective equipment (PPE) is able to protect the staff from infection in most cases, there remains the possibility of transmission of infection in the case of PPE safety breaches or during taking the PPE off, which can be a critical moment that needs strict attention and precaution.

The other side of the coin

Although there may be some risk of exposure of the operation theatre staff to COVID-19 during MIS, this risk remains hypothetical and its actual magnitude remains unknown.

The World Health Organization (WHO) [9] did not confirm airborne transmission SARS-COV-2 as the primary method of transmission. However, it may be possible in certain settings and procedures pertinent to the respiratory tract such as endotracheal intubation, bronchoscopy, and manual ventilation.

The main study upon which the assumption of airborne transmission of COVID-19 was proposed [6] generated aerosols using a three-jet nebulizer and fed into a Goldberg Drum under controlled conditions. This implies that the aerosol produced by this high-powered machine is not the same as that produced by normal human cough. Moreover, there is no current evidence that the aerosol generated in the clinical setting of laparoscopy is similar to that created by an experimentally induced aerosol-generating procedure [10].

In a recent study, investigators [10] sampled air in the room and anteroom of three COVID-19 patients. Sampling was done on two separate days over an isolation period of two weeks. The patients were isolated in airborne infection isolation rooms with 12 air exchanges per hour. SKC Universal pumps (SKC Ltd., Blandford Forum, UK) with 37-mm filter cassettes and 0.3-μm polytetrafluoroethylene filters for four hours at 5 L/min were used. The presence of SARS-COV2 in air samples was examined using real-time reverse transcriptase–polymerase chain reaction (RT-PCR) targeting RNA-dependent RNA polymerase and E genes. All air samples were negative to SARS-COR2. However, the study was limited by its small sample size and the fact that the volume of air sampled accounts for a small fraction of the total volume, in addition to the dilutional effect of air exchanges in the room on the presence of SARS-CoV-2 in the air.

Another study [11] employed a bundle approach for healthcare workers that comprised active and enhanced laboratory surveillance, early airborne infection isolation, rapid molecular diagnostic testing, and contact tracing. Although SARS-CoV2 was detected in one of 13 environmental samples, it was not found in any of the eight air samples collected at a distance of 10 cm from the patient’s chin with or without wearing a surgical mask.

Liu et al. [12] collected 35 aerosol samples from patient areas and medical staff areas of two hospitals and public areas in Wuhan city during the COVID-19 outbreak. The SARS-CoV-2 RNA concentration in the aerosol was determined by droplet digital polymerase chain reaction (ddPCR). One hospital had undetectable or low airborne SARS-CoV-2 concentration in the patient areas while the other hospital had a higher concentration that turned negative after the number of patients was reduced and rigorous sanitization was implemented.

Another report [13] investigated the air of the rooms of patients with confirmed COVID-19. Ten air samples were collected into the sterile standard midget impingers. Viral RNA was extracted from samples taken from the impingers and RT-PCR was used to verify the positivity of collected samples based on the virus genome sequence. All air samples collected at a distance up to 5 m from the patients’ beds were negative.

Furthermore, a recent paper in Nature [14] assessed the presence of SARS-COV-2 in different samples of COVID-19 positive patients. While the infectious virus was readily isolated from throat- and lung-derived samples, it was not isolated from blood, urine, and stool. As the virus was never found in blood samples, this raises an important question as to whether its concentration in the tissues within the abdominal cavity is sufficient to release infective virus in the surgical smoke emitted during MIS.

A number of recent reports [15,16] failed to detect SASR-COV-2 in the peritoneal fluid in COVID-19 infected patients undergoing laparoscopic surgery, namely appendectomy. Multiple samples of the peritoneal fluid and peritoneal washing were taken from asymptomatic COVID-19 patients and the virus was not isolated from all samples. While this observation may imply safety of laparoscopic procedures in COVID-19 patients, we have to remember that the viral load and severity of infection may have an impact on the presence of the virus in the peritoneal fluid.

In addition, a WHO analysis of more than 75 thousand patients with COVID-19 in China did not conclude the possibility of airborne transmission of the virus [9]. In light of the previously mentioned studies, the actual risk of airborne transmission of the virus in the setting of MIS is highly controversial.

In order to substantiate the risk of aerosolization of SARS-COV-2 RNA during MIS, the virus should be isolated from the plume emitted by electrocautery or energy devices. If SARS-COV-2 was indeed aerosolized in the surgical smoke akin to HBV, then it can be isolated from the smoke using high efficiency collectors in an experimental setting, then nested PCR can be used for detection of the virus RNA [17]. On the other hand, even if SARS-COR-2 was detected in the surgical smoke, the ability of the detected virus particles to induce active infection has not been examined yet in clinical or experimental settings.

Moreover, during prior viral outbreaks, transmission of other coronaviruses such as SARS and MERS-CoV through surgical smoke or laparoscopic gas was never confirmed [18]. Although particles of HPV and HBV have been detected in the surgical smoke, there is no solid evidence that transmission of respiratory or blood-borne infectious viruses through the surgical smoke and aerosolized gas is able to cause clinically active infection [19].

Precautions during MIS for patients with suspected or confirmed COVID-19

Recently, the experience of surgeons of China and Italy, countries that were most affected by the pandemic, was formulated into a set of recommendations on the use of laparoscopy in the setting of the COVID-19 pandemic [4]. It is important to note that these recommendations are not verified yet since they were mainly based on personal experiences of the surgeons rather than solid or definitive evidence.

These recommendations included protection of the operating staff with personal protective equipment (PPE), reducing the numbers of personnel to the lowest possible number, prevention and management of aerosol dispersal, management of artificial pneumopertionium, in addition to other technical aspects.

The authors recommended to avoid gush of body fluids by air leak, regular evacuation of smoke with suction devices, particularly before any extraperitoneal maneuver or conversion to open surgery, and avoiding two-way pneumoperitoneum insufflators to prevent colonization of SARS-COV-2 in the circulating aerosol in the pneumoperitoneum circuit or the insufflator.

It was also advisable to maintain pneumoperitoneum pressure and ventilation at the lowest possible levels that allow proper exposure of the surgical field. Also, minimizing the effect of pneumoperitoneum on lung function and circulation may help reduce pathogen susceptibility. The power settings of electrocautery should be as low as possible and the dissection time by electrocautery or ultrasonic scalpels should be shortened whenever possible to reduce smoke generation.

Another method to prevent COVID19 exposure during laparoscopy would be the use of devices to filter released CO² for aerosolized particles. Two types of filtration systems are available. First, the Stryker Pneumoclear Smoke Evacuation High Flow Tube sets (Stryker, Kalamazoo, MI, USA) which have an in-line HEPA filter that filters particles as small as 0.08 microns with 99.98% efficiency. Second, the ConMed Airseal delivery system (Conmed, Utica, NY, USA), which filters particles down to 0.1 microns with 99.99% efficiency [20].

A low-cost and effective method for smoke evacuation in laparoscopic surgery was devised by Mintz et al. [21]. The authors suggested connecting the electrostatic filters used for ventilation machines to the trocar evacuation port via standard tubing. These filters are certified for almost absolute effective protection against HBV and HCV. Since these viruses have a diameter of 42 nm and 30–60 nm, the same filtering efficiency is expected to apply for the SARS-COR-2 which has a larger diameter of 70–90 nm. No active suctioning is attached to this system.

Yeo et al. [22] proposed a safe system for evacuation of pneumopertionium during MIS. The system entails an intravenous drip set, suction valve, plastic suction tubing and surgical suction system with a heat moisture exchanger (HME) filter which has a high virus filtration rate reaching almost 100%. The authors explained the mechanism of action of this system that it allows finetuning of the smoke clearance by adjusting the suction settings. Summary of the precautions suggested when doing MIS during the pandemic is shown in Table 1.

Benefits of MIS in acute abdominal emergency during COVID-19 pandemic

Based on modest evidence, the use of MIS, mainly laparoscopy, in the treatment of acute abdominal emergency may be associated with an increased risk of exposure of the operating team to infection. However, the benefits of MIS for the patient and the hospital may outweigh this unverified risk.

Laparoscopy has a documented role in acute abdominal emergency. Due to its diagnostic and therapeutic advantages, laparoscopic surgery is useful for the majority of conditions underlying acute abdominal pain according to a panel consensus of the European Association of Endoscopic Surgeons (EAES) [23].

Indications for laparoscopy in acute abdominal emergency include the treatment of acute appendicitis, acute cholecystitis, acute complicated diverticulitis, perforated peptic ulcer, and bowel obstruction [24].

Benefits of laparoscopy to the patients include the avoidance of large wounds, decrease in blood loss and pain with subsequent less opioid requirement, lower complication rates, namely incisional hernia and abdominal adhesions, and expedited recovery. The faster recovery after laparoscopic surgery can also be beneficial to the hospital and perhaps to the community amid the COVID-19 pandemic. With shorter stay in the hospital after laparoscopic surgery, the overall costs of the procedure will be reduced and so will be the risk of exposure to COVID-19 [25].

Given the nature of the current pandemic, it may be more practical to use disposable laparoscopic instruments to minimize the risk of exposure to COVID-19. However, there is no current study or evidence to support or refute the use of disposable instruments in laparoscopy in the COVID-19 era.

Current recommendations of surgical societies

The most recent recommendations of SAGES and EAES [26] stated that there is very little evidence on the relative risks of minimally invasive surgery versus the open approach, specific to COVID-19. Given the possibility of viral contamination, they recommended to strictly employ protective measures for the operating room staff regardless of the approach to surgery used. They also highlighted the advantages of minimally invasive surgery and recommended to use PPE devices regardless of known or suspected COVID status and to safely evacuate pneumopertionium via filtration system before closure, trocar removal, specimen extraction, or conversion to open, and to use devices to filter the released gas for aerosolized particles, assuming aerosolization properties of the SARS-COV2.

The American College of Surgeons (ACS) [3] described laparoscopy as an aerosol-generating procedure that may increase risk to the healthcare worker and recommended wearing full PPE including an N95 mask or powered, air-purifying respirator that has been designed for the operation room. According to the ACS, data to recommend for/against an open versus laparoscopy approach are yet insufficient. However, the approach that minimizes operation time and maximizes safety for both patients and healthcare staff should be used at the discretion of the surgical team.

The Intercollegiate General Surgery Guidance on COVID-19 devised by the Royal College of Surgeons of Edinburg [27] recommended to consider laparoscopy selectively when the clinical benefit to the patient substantially exceeds the risk of potential viral transmission. They advised considerable caution in using laparoscopy amid the COVID-19 outbreak as it carries some risks of aerosol-type formation and infection, however the level of this risk has not been clearly defined.

The Italian Society of Colorectal Surgery [28] recommended to weight the potential hazards of MIS against the benefits of a shorter hospital stay and lower complication rate. If laparoscopic surgery be performed in COVID-19-positive patients, it should be done in a negative pressure room with ultra-filtration (smoke evacuation system or filtration) system used. Safe evacuation of pneumoperitoneum via a filtration system should be conducted before closure, trocar removal, specimen extraction, or conversion to open. The society strongly recommended to use appropriate trocar-size incisions in order to avoid air leaks.

The Italian Society of Obesity Surgery and Metabolic Diseases (SICOB) [29] devised a set of recommendations regarding the triage of bariatric procedures amid the current pandemic, how and when to resume bariatric surgery in phase 2, and precautions taken during laparoscopic surgery. The society recommended to avoid prolonged Trendelenburg positioning as it has deleterious effects on the cardiopulmonary function of COVID-19 patients, reduce the amount and size of trocars and the incisions made to insert them, keep the intra-abdominal pressure lower than usual and possibly below 10 mmHg, avoid sudden release of trocar valves, and minimize the utilization of energy devices.

A summary of the recommendations of the different surgical societies is shown in Table 2.