Monitoring Patients With Shortness of Breath With Repeated Ultrasound Examinations

Overview

Purpose of the study: The purpose of the trial is to investigate whether repeated ultrasound scans of the heart and lungs of patients with shortness of breath may help to optimize their treatment. This patient group is characterized by an extended hospitalization and a high mortality rate. Therefore, it is essential to be able to target the treatment in order to shorten length of stay, prevent readmissions, and improve survival in these patients. Ultrasound scanning used in this way is novel. The study method: Initially, all patients will receive standard evaluation and ultrasound of the heart and the lungs. Then the patients are randomly assigned into two groups. In one group, patients receive standard assessment and treatment. In the second group, the patients, in addition to standard examination and treatment, receive ultrasound scans of their heart and lungs after two hours and again fire hours after the first scan. After discharge, the subjects are followed for one year to evaluate what examinations and treatment they received during hospitalization, whether they have been readmitted or died.

Design: Multicenter, randomized, controlled, open-label, and pragmatic trial. Settings: Several different emergency departments (EDs) in Denmark. Study flow: After arrival, the patients are screened according to eligibility criteria. If patients meet the inclusion criteria and informed consent is obtained, the patients are randomly assigned to one of two groups. In both groups, the patients received standard evaluation, e.g., blood samples, physical examination, arterial blood gas, and in addition ultrasound examination of the heart and the lungs. In the intervention group, the patients are further examined with serial ultrasound scans of the heart and the lungs after two and four hours after the initial evaluation. In the course of admittance, the patients will have there baseline characteristics recorded together with the ultrasound findings, symptoms, and vitals. Symptoms will be recorded at a verbal dyspnea symptom scale (VDS) from 0-10. All data will be registered at the same time points to make comparisons: At 1, 2, 4 and after 5 hours. Sample size: This is calculated from the primary outcome and with an assumption of a power of 80%, type 1-error of 5%, and 10% dropouts. The calculations are based on previous studies using the VDS on patients with acute dyspnea. The sample size is 103 patients in each group. Statistical analysis: Baseline characteristics will be summarized and divided into the intervention and control group. Continuous variables will be summarized as means and standard deviation (SD) or medians and interquartile range (IQR) depending on the distribution of the variable. For categorical variables, frequencies and percentages will be reported. The primary outcome - change in dyspnea on VDS - will be compared between the two groups to detect any difference. Pairwise comparisons of VDS will be made at the same time points in both groups. The secondary outcomes: Length of stay, death, and the number of readmissions will be compared between the two groups to detect a difference. Time-to-event (dead or readmission) will be visualized with Kaplan Meier curves. In the case of lost to follow-up or other reasons for missing data both intention-to-treat and per-protocol analysis will be used. The secondary outcomes in the interventions group: The dynamic changes in inferior vena cava collapsibility index (IVC-CI) and the sum of B-lines will be expressed as means and SD or median and IQR depending on the distribution of the data and compared between the different time points. Furthermore, IVC-CI and the sum of B-lines will be compared to vitals and VDS-score to detect a correlation. The inter- and intraobserver variability regarding the focused ultrasound will be accessed. Data management: The registered data on each patient will be recorded and securely stored in an encrypted, logged, and password-protected database called REDCap. All adjustments in the database are logged. The patients are anonymized.