The article deals with extremely topical problem of the patient safety in anaesthesiology and intensive care. The medical aid complications and defects issue in anaesthesiologist practice is not only specifically medical, but also social significant. The analysis of frequency and nature of defects in anaesthesiology and intensive care was conducted. It was based on 280 forensic medical examinations with anaesthesiologist as an expert. The acquired data showed that treatment defects were found in 63.7% of cases. Special attention was paid to airway management defects. Results helped to determine at which stage and procedure the critical incidents had occurred, as well as their frequency and causes. Considering the discovered causes of defects in anaesthesiology and intensive care, measures aimed at preventing complications and increasing the anaesthesiology and intensive care quality were proposed.