Predictive value of neuro-ventilatory coupling combined with B-type natriuretic peptide in the weaning outcome in patients with chronic cardiac insufficiency

Abstract

Objective To evaluate the predictive value of neuro-ventilatory coupling (NVC) combined with B-type natriuretic peptide (BNP) in the weaning outcome in patients with chronic cardiac insufficiency. Methods A retrospective study was conducted. Sixty-four patients with chronic cardiac insufficiency undergoing mechanical ventilation admitted to Department of Critical Care Medicine of Mindong Hospital Affiliated to Fujian Medical University from December 2010 to December 2015 were enrolled. When the patients satisfied criteria for their first spontaneous breathing trial (SBT), a 30-minute SBT was attempted. The patients were divided into two groups as successful weaning group and weaning failure group. Electrical activity of the diaphragm (EAdi), NVC, BNP, NVC/BNP, index of rapid shallow breathing (f/VT), airway occlusion pressure (P0.1) and f/VT·P0.1 were measured at 0, 5 and 30 minutes of the SBT, the differences were compared between the success and failure groups. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the predictive value of each index. Results There were 37 patients successfully weaned in 64 patients enrolled, and 27 patients wean with failure, with the fail wean rate of 42.2%. There was no statistical difference in gender, age, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ) score, duration of ventilation, and the parameters reflecting breathing mechanics, gas exchange, hemodynamics, and cardiac function before weaning between the two groups. Compared with successful weaning group, cardiac index (CI) at 30 minutes of SBT in failed weaning group was significantly lowered, global end diastolic volume index (GEDVI) and extravascular lung water index (EVLWI) were significantly increased [CI (mL·s-1·m-2): 49.68±9.67 vs. 54.51±8.84, GEDVI (mL/m2): 747±47 vs. 711±37, EVLWI (mL/kg): 7.07±0.81 vs. 5.42±1.26, all P 16.44 μV with correct rate of 0.71; when NVC < 22.74 mL/μV, it had the highest sensitivity (70%) and specificity (82%) with correct rate of 0.76; when BNP < 284.00 ng/L, the sensitivity and specificity were 78% and 63% with correct rate of 0.70; and when NVC/BNP < 84.75 mL2·ng-1·μV-1, it had the highest sensitivity (88%) and specificity (82%) with correct rate of 0.83. f/VT and f/VT·P0.1 presented poor predictive performance in failed patients. Conclusion EAdi, NVC and BNP had higher accuracy in predicting weaning outcome, and NVC/BNP was the best index of weaning outcome in chronic cardiac insufficiency patients. Key words: B-type natriuretic peptide; Neuro-ventilatory coupling; Chronic cardiac insufficiency; Weaning from mechanical ventilation; Electrical activity of diaphragm