CASE DESCRIPTION
A 72-year-old male was transferred from a local hospital on March 18,
2020, due to severe hypoxia and hypercapnia. The patient was taking
medication for hypertension and dyslipidemia and was a nonsmoker. He
developed upper respiratory symptoms such as headache, fever, chilling
sensation, and cough 8 days before being transferred to our hospital. A
real-time reverse transcriptase-polymerase chain reaction test for
COVID-19 was done which confirmed COVID-19 infection 5 days prior to
being transferred to our hospital. He was an inpatient at a local
medical institution and was treated with antibiotics (levofloxacin) and
antiviral agent (lopinavir/ritonavir) 2 days before being transferred to
our hospital. However, the patient’s chest X-ray haziness was
aggravated, fever was sustained, and hypoxia worsened despite the
symptomatic treatment. His initial vital signs were blood pressure of
136/63 mmHg, heart rate of 79 beats/min, body temperature of 37.3℃,
respiratory rate of 40 breaths/min, and peripheral O2 saturation of 90%
on non-rebreather mask of 15 L/min. The pH, pO2, pCO2, and O2 saturation
were 7.318, 78.1 mmHg, 50.7 mmHg, and 93.8%, respectively, in the
arterial blood gas analysis. Chest X-ray demonstrated diffuse ground
glass opacities in the left middle and both lower lobes (Fig. 1).
Initial electrocardiogram (ECG) revealed normal sinus rhythm with a
heart rate of 90 beats/min, normal PR (172 ms) and QRS (92 ms)
intervals, and normal QT (350 ms) and QTc (428 ms) intervals (Fig. 2).
The patient underwent intubation and was started on mechanical
ventilator care 1 h after admission. Medical treatment was administered
with antibiotics (levofloxacin) and antiviral agent
(darunavir/cobicistat). A mechanical ventilator was applied, and
midazolam and fentanyl citrate were used for sedation. The heart rate
was stably maintained at 60–70 beats/min, and cardiac arrhythmia was
not observed. On day 2 of hospitalization, antibiotics was changed from
levofloxacin to piperacillin/tazobactam due to persistent fever. On
day 4 of admission, the antiviral agent was stopped due to liver enzyme
elevation. In addition, antibiotics (azithromycin) was added on day 6 of
hospitalization because chest radiography demonstrated deteriorating
pulmonary consolidation (Fig. 1). On day 9 of admission, a paroxysmal
complete atrioventricular (AV) block was observed on the ECG monitor
(Fig. 3). Paroxysmal complete AV block lasted for 5–10 s at the time of
occurrence and developed one to two times per hour. Changes in
consciousness, such as syncope, were not observed because the patient
was in the sedation state at the time of paroxysmal complete AV block
onset. Accordingly, we first identified and discontinued medication that
could induced cardiac arrhythmia. The antibiotics
piperacillin/tazobactam and azithromycin were discontinued and were
changed to a different class of antibiotics. In addition, the mechanical
ventilator setting value was adjusted in consideration of the
possibility of AV block due to vagal overstimulation due to an increase
in intrathoracic pressure and hyperinflation of the lungs. At the time,
the patient’s mechanical ventilator was set to assisted/controlled
mandatory ventilation – volume controlled ventilation mode with 340 ml
per inspiration of tidal volume (TV), 10 cmH2O of
positive end expiratory pressure (PEEP), 28 breaths/min of respiratory
rate, and 50% fraction of inspiration oxygen.
TV and PEEP were adjusted from 340 to 320 ml per inspiration and from 10
to 8 cmH2O, respectively. Paroxysmal complete AV block
did not occur 2 h after adjusting the mechanical ventilator, and
follow-up ECG revealed normal sinus rhythm with a heart rate of
68 beats/min (Fig. 4). Thereafter, cardiac arrhythmia including
paroxysmal complete AV block was not observed during the hospitalization
period. Fortunately, the patient gradually recovered from acute
respiratory distress syndrome. On day 13 of hospitalization, mechanical
ventilation was stopped and extubation was performed. Finally, the
patient was discharged 49 days after admission.