C-reactive protein on the fourth day of ICU admission predicts mortality and organ failure in critically ill surgical patients

Background

Plasma C-reactive protein (CRP) levels increase rapidly after various inflammatory conditions, including surgery. Although CRP measurements are used frequently in the ICU setting, their relation to the development of sepsis, organ failure and mortality is not well known.

Objective

To correlate plasma CRP levels with prognosis and hospital mortality in the postoperative period.

Design

A prospective cohort study.

Setting

A 19-bed medico-surgical ICU in a private hospital.

Patients

All surgical patients admitted to the ICU over a period of 4 months.

Measurements and results

In 2005, from September to November, 527 patients were admitted to the ICU. Of them, 435 (82.5%) patients were admitted for postoperative care, and 219 (50.3%) were male. The mean age of the whole group was 62.02 ± 16 years. Nine (2.06%) patients died during the postoperative period. Among the patients who died, the mean APACHE and SAPS 2 scores were 17.67 ± 9.40 and 52.4 ± 18.31, respectively. Among those who survived, the mean APACHE and SAPS 2 scores were 12.11 ± 6.35 and 24.66 ± 13.03, respectively. Plasma CRP levels during the first 3 days of the ICU stay were not statistically different between patients who survived and those who died. On the fourth day, the plasma CPR level was significantly higher in the group who died, compared with those who survived (28.133 ± 4.77 vs 13.849 ± 10.4; P = 0.037). Of interest is the fact that, on admission, the APACHE and SAPS 2 scores were higher in the group who survived. The area under the ROC curve for the analysis of plasma CRP levels on the fourth day of the ICU stay was 0.86 (95% CI 0.76–0.96) with 100% sensitivity and 75% specificity to predict death in surgical patients. The best cutoff point was 22.7 mg%. The mortality in the groups with fourth-day PCR <22.7 mg% and ≥ 22.7 mg% was 0 and 25%, respectively (P = 0.011).

Conclusion

In this cohort, a plasma CPR level higher than 22.7 mg% on the fourth day of ICU admission was a good tool to discriminate between patients who died and those who survived. Plasma CRP levels appear to be better at predicting mortality than the APACHE II and SAPS 2 scores at the time of ICU admission.