Discussion
ACS is one of the leading causes of mortality and morbidity in patients
with SCD.6 Given the propensity of pulmonary disease
in patients with SCD, any infectious process including SARS-CoV-2 can
exacerbate ACS and lead to life threatening refractory hypoxemic ARDS as
seen in our case through the sequestration of sickled RBCs. With limited
data detailing SARS-CoV-2 in children with SCD, our case illustrates key
elements that provide a treatment strategy for ECMO support which
allowed this patient to recover but also allowed for rehabilitation to
improve his candidacy for LTx.
As the ECMO circuit can exacerbate sickling and hemolysis, we believe
aggressive management of the HbS level maintaining a level ≤15% while
on ECMO was critical in our management and contributed to the positive
outcome for this patient as we believe it prevented end organ damage
from vaso-occlusive events from further sickling. Pro-active and
pre-planned changes of oxygenator or circuit based on fibrin deposit
burden and the free plasma hemoglobin level also prevented further
hemolysis leading to end organ dysfunction or disastrous circuit
failure. We also maximized the hydroxyurea therapy to increase the level
of anti-sickling HbF level, in an attempt to minimize overall blood
transfusion requirements, thereby lowering risk of allosensitization,
should he later require LTx. The hydroxyurea-induced increase in HbF
level also allowed liberalization of his exchange transfusion
requirement to maintain HbS levels <30% upon discharge. The
patient has returned home but continues to require chronic mechanical
ventilation and is only tolerating a very prolonged wean from mechanical
ventilation. He participates in physical rehabilitation without need for
re-hospitalization, which enhances his potential for full recovery or
makes his future candidacy for LTx more favorable as pre-transplant
hospitalizations is associated with increased morbidity and mortality
post-LTx.7