ObjectiveTo report a case of partial anomalous pulmonary vein drainage of the left lower lobe diagnosed after central venous cannulation.DesignRetrospective case review.SettingIntensive care unit.PatientA 76-yr-old woman with obstructive acute renal failure requiring hemodialysis.InterventionsCentral venous cannulation and hemodialysis.Measurements and Main ResultsThe diagnosis was suggested by chest radiography after placement of a central venous catheter through the left internal jugular vein. Pressure measurements at the tip of the catheter showed a venous waveform. Oxygen blood content on samples of blood was higher than on peripheral arterial blood. Computed tomography with intravenous contrast was not conclusive. Diagnosis was confirmed with transcatheter phlebography.ConclusionsIt is important for the intensivist to be aware of this infrequent variant when a central venous catheter takes an abnormal route and drains low-pressure, arterialized blood.