Comments on: All India Ophthalmic Society-Indian Journal of Ophthalmology Consensus statement on preferred practices during COVID-19 Pandemic.

Abstract

We read with interest the article by Sengupta et al. titled AIOS-IJO Consensus statement on preferred practices during COVID-19 pandemic.[1] We congratulate the entire team for this timely and elaborate guideline. We would like clarity on some of the guidelines with respect to precautions at operating room procedures/surgeries. The two likely scenarios would be Presumed non-COVID cases requiring routine ophthalmic surgery. COVID-positive/COVID-suspect cases requiring emergency ophthalmic surgery. The scope of these guidelines is not clear in which of the above situation we need to apply OR guidelines with respect to the air ventilation. In the second scenario, the authors advise operating these cases in dedicated government-authorized centers. It is unclear whether one needs to change the previously accepted standard of care in the first scenario. In the second scenario, if these guidelines are to be applied for COVID-positive/suspected patients requiring emergency ophthalmic surgery, then we would like to point out certain guidelines that require further practical clarifications for making them operational. Guideline (d) mentions air handling units (AHU) with increased fresh air exchange. If possible, consider retrofitting dynamic ultraviolet (UV) and ultrafilters to high-efficiency particulate air (HEPA) reduce turbulence in the operating room. This would mean changing the current AHU fan with a newer fan of higher capacity to increase the fresh air intake, replacing the existing HEPA filters with ultra-HEPA filters, and adding an appropriate UV Lamp. Even then this would still be a positive pressure ventilation system. To make this a negative pressure system, another separate duct with a powerful fan is required to exhaust the OR air to the outside environment after appropriate treatment. Guideline (n) says stop positive ventilation in the theater during the procedure, if feasible, and for at least 20 min after the patient has left the theater. This is supposed to create a temporary negative pressure environment. However, for this to work, the air supplied to the area adjacent to the OR room including the corridors must be through an AHU. Only then the air immediately outside the OR will enter into it when we switch off the OR AHU. If the air quality immediately outside OR does not meet the desired air quality standards for ORs, then this would result in potentially contaminated air entering the OR resulting in a higher risk of infection. This risk has to be borne in mind. If the area adjacent to the OR (corridor/ante-room) is not supplied by a positive ventilation system then the pressures will only equalize between the adjacent areas. Many ophthalmic ORs have standalone AHU systems that supply only the OR with conditioned HEPA filtered air. In these ORs, by just stopping the positive pressure ventilation, our intention of creating a negative pressure system will not be achieved. Another potential problem would be temperature fluctuations within the OR when we practically are shutting off the AHU for close to 45 minutes (during and after the procedure). This would be very uncomfortable for health care workers and operating surgeons especially when they are wearing complete personal protective equipment. It is also unclear when exactly one should restart the AHU and for how long should one wait before starting the next case? Indian Society of Heating Refrigeration and Air Conditioning Engineers (ISHRAE)[2] have come out with guidelines on how to convert existing AHU systems into COVID-19-care areas. They also recommend setting the room temperature between 24 and 30°C while maintaining the relative humidity between 40 and 60%. We understand a perfect guideline is difficult to arrive at in an ever-changing scenario. Detailed guidelines on OR air ventilation in consultation with experts/ISHRAE would be ideal as we have ophthalmic theaters using varied ventilation systems in our country. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.