Hypoxemia, arterial desaturation (isolated)
(Fr: hypoxémie/désaturation isolée). Hypoxemia may reflect 1) Deteriorated VA/Q indicating early lung injury, cell sequestration in the distal pulmonary circulation 2) Ventilatory depression (see under IX a, c, d, e), in this case typically associated with a raise in arterial PCO2. See also under methemoglobinemia, a condition that commonly alters SpO2 readings. Rare instances of spurious hypoxemia from oxygen steal or larceny were described in high-WBC-acute leukemia patients receiving ATRA.