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.