Sudden complete obstruction of breathing circuit during postural change upon completion of thoracic spinal surgery in a pediatric patient.

Positioning patients during the perioperative period is a common event to anesthesiologists. A variety of complications may arise during this cumbrous moment. We describe a rare circumstance that we came across immediately after changing the posture of a pediatric patient at the end of thoracic spinal surgery. A total occlusion of the combined heat-moisture exchanger (HME) and bacterial/viral filter was responsible for breathing circuit obstruction. The use of the combined HME and bacterial/viral filter is not entirely riskless during general anesthesia.