Deterioration of conjunctival PO2after CPR

An 82-year-old man was resuscitated following cardiac arrest suffered outside the hospital. Conjunctival oxygenation (PcjO 2 ), as measured by a conjunctival P0 2 monitor, increased in the immediate post-resuscitation period (60 min) and neurologic status improved. The PcjO 2 steadily declined over the next three hours. During the period of declining PcjO 2 , the systolic blood pressure tended to remain stable (104 mm Hg ± 18), the arterial PO 2 (PaO 2 ) was ⩾ 103 mm Hg, and the PcjO 2 /PaO 2 ratio initially increased, while the PcjO 2 /arterial oxygen content (CaO 2 ) ratio and neurologic status declined. The rise and subsequent fall of PcjO 2 in this patient paralleled the neurologic status and may be consistent with the cerebral reperfusion/hypoperfusion phenomena observed in experimental preparations of resuscitation from circulatory arrest.