Incidence and risk factors of gastrointestinal bleeding in mechanically ventilated patients

The widespread use of gastrointestinal bleeding prophylaxis in critically ill patients was one of the most controversial issues. Since few studies reported the incidence of gastrointestinal bleeding in mechanically ventilated patients, this study aimed to identify the incidence and risk factors related to gastrointestinal bleeding in patients undergoing mechanical ventilation for more than 48 hours.

A total of 283 ICU patients who had received mechanical ventilation for longer than 48 hours at a provincial hospital affiliated to Shandong University from January 1, 2007 to December 31, 2009 were analyzed retrospectively. Those were excluded from the study if they had a history of gastrointestinal bleeding or ulceration, recent gastrointestinal surgery, brain death and active bleeding from the nose or throat. Demographic data of the patients included patient age, diagnosis on admission, duration of ICU stay, duration of ventilation, patterns and parameters of ventilation, ICU mortality, APACHE II score, multiple organ dysfunction, and indexes of biochemistry, kidney function, liver function and coagulation function. Risk factors of gastrointestinal bleeding were analyzed by univariate analysis and multiple logistic regression analysis.

In the 242 patients who were given mechanical ventilation longer than 48 hours, the incidence of gastrointestinal bleeding was 46.7%. The bleeding in 3.3% of the patients was clinically significant. Significant risk factors were peak inspiratory pressure ≥30cmH2O, renal failure, liver failure, PLT count<50×10(9)/L and prolonged APTT. Enteral nutrition had a beneficial effect on gastrointestinal bleeding. However, the multiple logistic regression analysis revealed that the independent risk factors of gastrointestinal bleeding were as follows: high pressure ventilator setting ≥ 30cmH2O(RR=3.478, 95%CI=2.208-10.733), renal failure(RR=1.687, 95%CI = 1.098-3.482), PLT count<50×1 0(9)/L (RR=3.762, 95%CI=2.346-14.685), and prolonged APTT(RR=5.368, 95%CI=2.487-11.266). Enteral nutrition(RR=0.436, 95%CI= 0.346-0.764) was the independent protective factor.

The incidence of gastrointestinal bleeding was high in the patients who received mechanical ventilation, and bleeding usually occurred within the first 48 hours. High pressure ventilator setting, renal failure, decreased PLT count and prolonged APTT were the significant risk factors of gastrointestinal bleeding. However, enteral nutrition was the independent protective factor.