Discussion
The COVID-19 pandemic continues to ravage surgical care of critically ill patients. Patients undergoing CABG, who develop COVID-19 infection in the peri-operative period, are at an increased risk of morbidities and mortality, with prolonged hospital stay.7 In our series, both patients had respiratory failure, needing VV-ECMO support with long hospital stays. However, the outcome was worse for the patient with pre-existing comorbidities of morbid obesity, diabetes mellitus, hypertension, and COPD.
Since the beginning of the pandemic, hospitals have been brainstorming to design protocols to test asymptomatic patients being admitted for ‘routine’ cardiac surgeries. Initially, the testing was limited to the high-risk population group, but very soon it was extended to pre-operatively screen all patients undergoing surgery. In our case, both patients had pre-operative negative COVID-19 tests but tested positive soon after surgery. Whether the initial result was false-negative8 and the patients contracted the virus pre-operatively, either prior to admission or in the hospital, is difficult to ascertain. The clinical manifestations, however, only appeared in the early post-operative period. Evidence suggests that CPB activates inflammatory responses which can lead to lung tissue damage as well as increased pulmonary endothelial permeability.9The cumulative effect of inflammation from CABG and COVID-19 is a possible source for the morbidity and mortality in patients with COVID-19 infection peri-operatively.
Both patients had similar clinical presentations, including ventilatory dyssynchrony, in the immediate post-operative period, leading to escalating ventilator parameters and sedation requirements. Veno-venous ECMO was initiated early on the first patient, one day after the diagnosis of COVID-19, whereas it was initiated eight days after diagnosis on the second patient. The role of early institution of VV-ECMO in severe COVID-19 infection is being investigated10, specially in post cardiotomy patients.
Cardiac surgery volumes have dramatically reduced across the nation during the pandemic, with an even more dramatic increase in operative mortality.5 In order to safely perform ‘routine, low-risk’ cardiac surgeries, one must have robust and effective pre-surgery screening protocols, with a low threshold to test patients again post-operatively should it be needed clinically. Patients with comorbidities such as advanced age, diabetes mellitus, obesity, hypertension, and COPD are possibly at increased risk of adverse outcomes should they contract COVID-19, and special care should be taken in this population. Early institution of VV-ECMO may be beneficial, but further studies are needed in this matter.