Beware of "curare cleft" like changes during unilateral capnothorax.

Capnography is a standard monitoring tool during general anaesthesia. Diaphragmatic movement with the weaning of muscle relaxant effect produces the characteristic "curare cleft" on capnography. Various artefacts can mimick this trace intraoperatively. Cautious interpretation and identification of these is essential to avoid any undue overdosing of the patients with muscle relaxants. We report "curare cleft" like artefact during ventilation with a single lumen tube in a patient with unilateral capnothorax undergoing minimally invasive esophagectomy.