Emergency reinstitution of cardiopulmonary bypass following cardiac surgery: outcome justifies the cost

Abstract

Crash back on bypass (crash-BOB) is occasionally required in the resuscitation of patients developing life-threatening complications following cardiac surgery. This study aims to determine the incidence, aetiology and cost-effectiveness of such intervention. Retrospective review of all crash-BOB patients over 5.5 years at one hospital. The incidence of crash-BOB was 0.8% and occurred at a mean of 7 h post-operatively (range 1 h-20 days). Pre-operative Parsonnet scores were similar to the overall population of patients undergoing surgery in our institution (mean score 10; range 0-45). The original cardiac operations were coronary revascularization (39), valve surgery (12) and others (4). Indications for crash-BOB were cardiac arrest (23), bleeding (20), hypotension (7), ischaemia (1) and others (4). Of the 55 patients, 20 died on the operating table. Of the remaining 35, a further 12 died in hospital. Overall survival was therefore 42%. Where crash-BOB was for bleeding, 17 of 20 patients (85%) survived to leave theatre, of whom 11 patients (55%) left hospital alive. In the 35 non-bleeders, only 18 (51%) survived crash-BOB and 12 (34%) left hospital alive. Sixteen patients required a second period of aortic cross-clamping of whom 13 (81%) survived to leave theatre, and 11 (69%) left hospital alive. Conversely, of nine patients in whom no specific diagnosis was found during crash-BOB, only two (22%) survived the procedure and none survived to hospital discharge. Multiple logistic regression identified pre-operative Parsonnet score (P=0.045) and the need for aortic cross-clamping to deal with an identified surgical problem (P=0.03) as significant predictors of hospital survival. Indication for crash-BOB (bleeder/non-bleeder) failed to reach significance (P=0.08). Age, sex, intra-aortic balloon pump use at the primary procedure, and time following the primary procedure to crash-BOB were not identified as predictors of hospital survival. Of the 23 hospital survivors, three patients suffered a stroke post-operatively and made a good functional recovery prior to discharge. Two patients developed sternal wound dehiscence requiring surgical rewiring. At follow-up (mean 3 years, range 1-6 years), 19 patients were in NYHA class I and four were in class II. Crash-BOB patients required an average of 8 extra intensive care days and 2 extra ward days. The total cost of these resources was pound164900 (including theatre time, cardiopulmonary bypass and intra-aortic balloon pump use). This was equivalent to pound7170 per life saved. Crash-BOB occurred in 0.8% of cases and was associated with a survival to discharge of 42%, and a justifiable cost of only pound7170 per life saved. Establishing an accurate diagnosis for the cause of clinical deterioration resulting in crash-BOB intervention was important, and the need for a further period of aortic cross-clamping did not preclude a favourable outcome.