The incidence and cause of emergency oxygenator changeovers

Emergency oxygenator changeover presents as an important potential hazard during cardiopulmonary bypass. In order to assess the frequency and possible causes of this event a retrospective survey was conducted of cardiothoracic units in the UK and Ireland. The survey was sent to these units in 1993 to cover the period from 1990 to 1992 inclusive and again in 1997 to cover the period from 1994 to 1996 inclusive. The total number of procedures reported in 1993 was 68937 (response of 63%), among which there were 17 emergency oxygenator changeovers representing an incidence of one for every 4055 cases. The use of aprotinin was associated with nine of these incidents. Two other incidents occurred due to leaking oxygenators. The total number of procedures reported in 1997 was 97313 (response of 70%), among which there were 21 emergency oxygenator changeovers, representing an incidence of one for every 4634 cases. The use of aprotinin was only associated with two of these incidents while seven were due to the development of a high trans-oxygenator pressure gradient and six occurred due to leaking oxygenators.