Case series
Patient 1: A 42-year-old, hypertensive gentleman presented
with unstable angina and was diagnosed with triple vessel coronary
artery disease by left heart catheterization. His initial hemodynamics
and labs were within normal limits and are described in Table 1.
Pre-operative arterial blood gas (ABG) analysis was normal on room air
(Table 2). Patient tested negative for COVID-19 by reverse
transcription polymerase chain reaction (RT-PCR) one day prior to the
CABG procedure.
The patient underwent on-pump CABG x 3 (left internal mammary artery to
the left anterior descending artery, sequential saphenous vein graft to
the posterior descending and obtuse marginal arteries). The surgery was
carried out uneventfully and the intra-operative ABG on a fraction of
inspired oxygen (FiO2) of 70% is depicted in Table 2. The patient was
weaned off cardio-pulmonary bypass on no inotropes, and a small dose of
vasopressor. In the intensive care unit, the first ABG on a FiO2 of
100% was abnormal with a partial pressure of oxygen (PO2) of 69 mmHg
(Table 2). A few hours after surgery, the patient became hypotensive
with low cardiac indices. An epinephrine infusion was started, and
vasopressors were escalated. The patient was initially dyssynchronous on
the ventilator and needed deepened sedation. He continued to have low
arterial saturations on escalating ventilatory support over the next
24-48 hours. A repeat COVID-19 RT-PCR was sent due to the ongoing
difficulty with ventilation, which returned positive on post-operative
day (POD)-2.
On POD-3, the patient was placed on peripheral veno-venous
extracorporeal membrane oxygenation (VV-ECMO). He responded well on ECMO
with improved arterial saturations. The ECMO run was complicated by
positive blood cultures, for which antibiotics were escalated. A
percutaneous tracheostomy was performed on POD-15. After being supported
on VV-ECMO for 18 days, the patient was successfully weaned off and
decannulated. He was then slowly weaned off the ventilator and after
being on the tracheostomy for 22 days, he was then decannulated and was
discharged home.
Patient 2: A 62-year-old morbidly obese lady with sleep
apnea, type-2 diabetes mellitus, chronic obstructive pulmonary disease
on home oxygen, and hypertension presented to the hospital with non-ST
elevation myocardial infarction. Her initial hemodynamics and labs were
within normal limits (Table 1) except a random blood sugar of 322 mg/dl,
with a HbA1c of 9.2%. Coronary angiography revealed critical
three-vessel disease. Her chest x-ray revealed bronchopneumonia of right
lower lobe, for which antibiotics were initiated. Her pre-operative ABG
on 3 liters of oxygen/minute is depicted in Table 2. She tested negative
for COVID-19 six days prior to surgery by RT-PCR.
After medical optimization, she underwent on-pump CABG x 3 (left
internal mammary artery to the left anterior descending artery and
individual reverse saphenous vein grafts to the obtuse marginal and
right coronary arteries). The surgery was carried out uneventfully, and
she left the operating room on no inotropes or vasopressors.
Post-operatively, she developed hypoxia with escalating PEEP and FiO2
requirements (Table 2). Her cardiac indices were borderline low, and she
was started on an epinephrine and milrinone infusion. The ventilatory
struggles continued for the next 48-72 hours, with the patient being
dyssynchronous on the ventilator, responding marginally to ketamine
infusion. On POD-6, RT-PCR for COVID-19 returned positive, and she was
started on remdesivir. There was marginal improvement in oxygenation,
and she was supported on the ventilator for another 7 days. On POD-14,
she was placed on peripheral VV-ECMO. She initially responded well to
ECMO, but later developed heparin-induced thrombocytopenia (HIT). She
also had intermittent fevers, with escalating antibiotic requirements. A
percutaneous tracheostomy was also performed. However, she showed
improvement from a respiratory standpoint, and after 12 days on ECMO
support, she was weaned off and decannulated. The patient then remained
stable for 24-48 hours, but then started developing significantly
elevated liver function markers with abdominal distention. A rising
serum lactate levels led to the suspicion of bowel ischemia, and an
exploratory laparotomy was performed. The laparotomy revealed extensive
small bowel ischemia, and given the extent of the disease, a decision
was reached with the family to make her comfort care.