Orthodeoxia and platypnoea after acute organophosphorus poisoning reversed by CPAP: a newly described cause and review of the literature.

The case of a 60-year-old male patient, who survived severe organophosphorus poisoning, and subsequently developed platypnoea and orthodeoxia is described. The patient was mechanically ventilated for a long period of time in the intensive care unit. During the weaning trial, he developed platypnoea and orthodeoxia (PaO2 85 mmHg in recumbency, and 40 mmHg in upright position). Interestingly, the patient's orthodeoxia was alleviated on continuous positive airway pressure (CPAP) treatment. This is a newly described cause of the platypnoea-orthodeoxia syndrome. The possible pathophysiological mechanisms are discussed and a review of the reported abnormal states associated with this condition is presented.