Association between blood transfusion and ventilator-associated events: a nested case-control study.

OBJECTIVES

The association between blood transfusion and ventilator-associated events (VAEs) has not been fully understood. We sought to determine whether blood transfusion increases the risk of a VAE.

DESIGN

Nested case-control study.

SETTING

This study was based on a registry of healthcare-associated infections in intensive care units at West China Hospital system.

PATIENTS

1,657 VAE cases and 3,293 matched controls were identified.

METHODS

For each case, 2 controls were randomly selected using incidence density sampling. We defined blood transfusion as a time-dependent variable, and we used weighted Cox models to calculate hazard ratios (HRs) for all 3 tiers of VAEs.

RESULTS

Blood transfusion was associated with increased risk of ventilator-associated complication-plus (VAC-plus; HR, 1.47; 95% CI, 1.22-1.77; P <.001), VAC-only (HR, 1.29; 95% CI, 1.01-1.65; P = .038), infection-related VAC-plus (IVAC-plus; HR, 1.78; 95% CI, 1.33-2.39; P < .001), and possible ventilator-associated pneumonia (PVAP; HR, 2.10; 95% CI, 1.10-3.99; P = .024). Red blood cell (RBC) transfusion was also associated with increased risk of VAC-plus (HR, 1.34; 95% CI, 1.08-1.65; P = .007), IVAC-plus (HR, 1.70; 95% CI, 1.22-2.36; P = .002), and PVAP (HR, 2.49; 95% CI, 1.17-5.28; P = .018). Compared to patients without transfusion, the risk of VAE was significantly higher in patients with RBC transfusions of >3 units (HR, 1.73; 95% CI, 1.25-2.40; P = .001) but not in those with RBC transfusions of 0-3 units.

CONCLUSION

Blood transfusions were associated with increased risk of all tiers of VAE. The risk was significantly higher among patients who were transfused with >3 units of RBCs.