Posterior Reversible Encephalopathy Syndrome (PRES) is a neurological complication associated with several medical conditions and it has been described in clinical findings of seizures, headache, vomiting, altered mental status, and visual changes and focal neurologic deficit, in conjunction with radiological findings of primarily posterior cerebral white matter edema of both cerebral hemispheres. PRES can develop in a wide array situations including pregnancy and postpartum in patients with or without symptoms and signs of eclampsia. A prompt diagnosis of PRES by magnetic resonance imaging and an immediate antihypertensive and anticonvulsant therapy can help to prevent serious complications. The clinical case presented deals with a 35 year-old pregnant woman whose history of eclampsia was observed after a cesarean section.

OBJECTIVE:To determine the incidence of hypoxaemia and the efficacy of oxygen therapy in the early postoperative period.DESIGN:Prospective, randomized study.SETTING:Regional hospital.PATIENTS:89 patients undergoing general anaesthesia divided into two groups, I (n = 45) and II (n = 44).INTERVENTIONS:Patients of group I breathed room air while patients of group II received supplementary oxygen.MEASUREMENTS AND MAIN RESULTS:Oxygenation was monitored continuously for 60 minutes with a pulse oximeter after the end of surgery; hypoxaemia was graded into four values of SpO2: mild (86-90%), moderate (81-85%), severe (76-80%), extreme (< or = 76%). One or more episodes of mild hypoxaemia were recorded in 68% of patients in group I and in 36% of patients in group II (p < 0.005); moderate hypoxaemia were recorded in 51% of patients in group I compared with 13% of patients in group II (p < 0.001). Episodes of severe or extreme hypoxaemia were recorded in 22% and in 6% of patients in group I; no patients in group II exhibited such small values of saturation. The smallest recorded SpO2 values were 81 +/- 5.94% in group I and 89 +/- 8.63% in group II (p < 0.001).CONCLUSIONS:There is a high incidence of clinically unsuspected hypoxaemia in the early postoperative period, the use of supplemental oxygen reduces but does not prevent hypoxaemic episodes, every patient should be monitored continuously with a pulse oximeter in the recovery room.