A recent study has shown that patients undergoing one-lung ventilation, repeated intermittent hypoxic stimuli to the operative lung may help reduce hypoxemia by promoting hypoxic pulmonary vasoconstriction.
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Experts facilitated a parallel-group, double-blinded,
randomized trial involving two cohorts of 68 patients each; all participants
were undergoing one-lung ventilation. Intervention arm received intermittent
hypoxia before surgery, wherein the nondependent lung was not ventilated for 2
minutes before being ventilated for the same duration of time; the dependent
lung was continuously ventilated.
On the other hand, controls were put under continuous
normoxia, where both lungs were ventilated for 20 minutes. Primary research result
was the number of hypoxemic patients, defined as oxygen saturation <95%
during the procedure.
Experts discovered that hypoxemia occurred less
frequently in the hypoxemia vs normoxemia group (8.8% vs 25%), with the difference
resulting in a statistically significant risk estimate.
Likewise, 30- and 60-minute measurements for the
partial pressure of oxygen as well as for the ration between PaO2 and the fractional
inspired oxygen were significantly higher in patients receiving intermittent
hypoxia. Contrarywise, the 30-minute alveolar-arterial pressure gradient and
shunt index were significantly lowered in these patients.
Regarding safety, the experts reported no significant
difference in the rates of adverse events/effects between arms.
Source: PLoS One 2021