[Mechanics of breathing during anaesthesia with controlled ventilation by means of the engström ecs 2000 respirator (author's transl)].

Compliance, resistance, gas flow, blood gas tension and intrapulmonary shunt volume were measured in 20 anaesthetized patients ventilated by the volume-controlled Engström respirator ECS 2000. All patients had neurosurgical or vascular procedures. Anaesthesia lasted for at least 180 minutes. 10 patients were ventilated with a tidal volume of 6 ml/kg bodyweight, another 10 with a tidal volume of 15 ml/kg bodyweight. During the whole period of observation compliance did not decrease significantly in either group and the intrapulmonary shunt volume and the blood gases remained practically unchanged. Ventilation with the large tidal volume was characterized by better compliance and oxygenation indicating that the mechanics of breathing and the intrapulmonary gas exchange benefit from larger tidal volumes. Due to the special features of the Engström respirator as regards air flow and pressure steady ventilation with a low tidal volume of 6 ml/kg bodyweight does not result in a significant decrease in compliance and an increase in shunt volume as is the case with other types of respirators.