Correlation factor analysis on constipation in long-term ventilated patients in intensive care unit: a prospective observational cohort study / 中华危重病急救医学

ABSTRACT

Objective To explore the factors associated with delayed defecation in long-term ventilated patients in intensivecare unit (ICU) and their potential effect on prognosis.Methods A prospective observational cohort study was conducted. The patients admitted to general ICU of the Affiliated Hospital of Qingdao University from October 1st in 2013 to September 30th in 2015 who underwent mechanical ventilation (MV) for ≥6 days were enrolled, and they were divided into early defecation group ( 0.05). Compared with the early defecation group, late defecation group had less patients with loose stools or watery stool at first time [15.7% (13/83) vs. 33.3% (18/54)], more patients using morphine and the usage of epinephrine/norepinephrine more than 24 hours [48.2% (40/83) vs. 40.7% (22/54), 42.2%(35/83) vs. 29.6% (16/54)], higher the maximum PEEP level [cmH2O (1 cmH2O = 0.098 kPa) 7.9±3.7 vs. 6.7±3.5], lower the minimal systolic blood pressure [mmHg (1 mmHg = 0.133 kPa) 74.8±28.1 vs. 88.9±30.2] and more severe of hypoxemia [PaO2/FiO2 < 150 mmHg, 54.2% (5/83) vs. 44.4% (24/53)], all of which had significant differences (allP < 0.05). Factors found statistical significances by single factor analysis were enrolled in the multiple regression analysis, which showed that PaO2/FiO2 < 150 mmHg and systolic blood pressure < 90 mmHg were independently associated with a delay in defecation in patients undergoing long-term MV [PaO2/FiO2 < 150 mmHg adjusted hazard rate 1.415, 95% confidence interval (95%CI) = 1.061-1.590,P = 0.026; systolic blood pressure 70-89 mmHgHR = 1.461, 95%CI = 1.164-1.788, P = 0.002; systolic blood pressure ≤ 69 mmHg adjusted hazard rate= 1.273, 95%CI = 1.010-1.587,P = 0.034). ICU mortality, the length of ICU stay, CVC indwelling time, duration of MV, ICU acquired bacterial infection rate, and the incidence of VAP at 7 days of MV in late defecation group were significantly higher than those of early defecation group [ICU mortality rate 15.7% (13/83) vs. 7.4% (4/54), the length of ICU stay (day) 17.0 (14.0, 23.0) vs. 15.0 (13.8, 20.0), CVC indwelling time (days) 12.0 (10.0, 14.0) vs. 10.0 (9.0, 11.3), duration of MV (days) 14.0 (10.0, 20.0) vs. 11.0 (9.8, 15.3), ICU acquired bacterial infections rate 60.2% (50/83) vs. 14.8% (8/54), the incidence of VAP 32.5% (27/83) vs. 14.8% (8/54); allP < 0.05]. There was no significant difference in LOD score between both groups. The LOD scores at 4 days and 9 days of MV in late defecation group were significantly higher than those of early defecation group (6.41±4.37 vs. 5.21±3.12, 4.33±2.20 vs. 3.50±2.90, bothP < 0.01).Conclusions PaO2/FiO2 < 150 mmHg and systolic blood pressure < 90 mmHg during the first 5 days of MV were independently associated with a delay in defecation in patients undergoing long-term MV. The results suggest that constipation is associated with adverse outcomes in long-term ventilated patients.