Bedside lung ultrasound for monitoring the effectiveness of prehospital treatment with continuous positive airway pressure in acute decompensated heart failure.

Abstract

The aim of this pilot study was to determine the usefulness of prehospital lung ultrasound in monitoring the effectiveness of treatment with continuous positive airway pressure (CPAP) versus standard therapy in patients with acute decompensated heart failure (ADHF). Twenty patients with ADHF were enrolled in this prospective, observational study. They were allocated randomly to a CPAP group (CPAP and standard therapy) or a control group (standard therapy only). Lung ultrasound was performed in each group and B-lines were counted and compared before and after treatment. There were statistically significant differences before and after treatment in partial pressure of end-tidal carbon dioxide (29.9±5.2 vs. 32.9±5.5 mmHg, P=0.011), respiratory rate (33.3±9.3 vs. 26.6±7.5 min, P=0.013), arterial oxygen saturation (82.0±9.4 vs. 97.3±1.3%, P<0.001), and total number of B-lines (46.9±14.8 vs. 29.0±16.2, P<0.001) in the CPAP group. There was a significant difference in required O2 added to either therapy to obtain adequate saturation - 40% in the CPAP group versus 100% in the control group (P<0.001). Percentage of positive ultrasound lung scans reduced in the middle axillary line and reached a statistically significant difference in the CPAP group [67 vs. 25% in medium right, P=0.017; 91 vs. 55% in basal right (fourth intercostal space), P=0.038; 83 vs. 33% in medium left, P=0.007; and 92 vs. 58% in basal left (fourth intercostal space), P=0.039]. Bedside lung ultrasound is a reliable monitoring tool in a prehospital emergency setting and findings from lung ultrasound scans correspond with improved hemodynamic parameters in patients with ADHF treated with CPAP compared with standard therapy only.