Parsonnet score is a good predictor of the duration of intensive care unit stay following cardiac surgery

Abstract

OBJECTIVE To investigate the value of the Parsonnet score (PS) in identifying preoperatively patients that are likely to spend < 24 hours on the intensive care unit (ICU) following cardiac surgery.

METHOD Prospectively collected data on 5591 patients were analysed. PS, mortality, the length of stay on the ICU (ICU-LOS), number of patients with clinical evidence of stroke, need for haemofiltration, resternotomy for bleeding, tracheostomy, and use of intra-aortic balloon pump were documented as outcomes. A receiver operating characteristic (ROC) curve constructed using PS as a predictor of ICU stay < 24 hours identified a PS of 10 as the best cut off point that would predict ICU-LOS < 24 hours. The patients were therefore stratified by PS into two groups, those with a PS of 0 to 9 (PS 0–9) and those with a PS of 10 and above (PS 10+).

RESULTS The ROC curve constructed using PS as a predictor of ICU stay < 24 hours had an area under the curve of 0.70 (0.01). The maximum efficiency of the test was at a sensitivity of 0.68. This corresponded to PS 10. The positive predictive value of the test at this score was 90.5%. Patients with PS 0–9 had a mean ICU stay of 1.49 days, while patients with PS 10+ had a mean ICU stay of 2.89 days (p = 0.01). The risk of stroke, use of intra-aortic balloon pump, requirement for haemofiltration, need for tracheostomy, and risk of resternotomy for bleeding were each significantly less in patients with PS 0–9 versus those with a score of PS 10+ (p < 0.01 in all cases). The risk of a single complication was 4.7% (PS 0–9)v 15.2% (PS 10+) (p < 0.01).

CONCLUSION PS is an impartial and objective method of predicting postoperative complications and ICU stay < 24 hours. This is of value in selecting a cohort of patients likely to maintain a smooth flow of patients through the cardiothoracic unit when resources are limited to a few free ICU beds.