Incidence and Impact of ICU-acquired Diaphragm Weakness

Overview

ICU survivors are at an increased risk of hospital and ICU readmission. Among the complications of ICU stay, diaphragmatic dysfunction is common, with a prevalence of 60 to 80%, and is associated with increased mortality and prolonged hospital stays. Furthermore, several studies have reported that the observation of impaired respiratory muscle function upon ICU discharge is associated with a poor long-term prognosis. However, the incidence and prognostic impact of persistent diaphragmatic dysfunction at ICU discharge have never been evaluated. The measurement of dyspnea, a composite evaluation of respiratory muscle function, has not been assessed for predicting prognosis upon ICU discharge. The hypothesis of the project is that the presence of ICU-acquired diaphragmatic dysfunction at ICU discharge is associated with a poorer prognosis within 90 days.

Diaphragmatic function of patients will be assessed by ultrasound within 24 hours following the weaning from ventilatory support and on the day the patient is deemed eligible for ICU discharge. ICU discharge will be defined a priori using a checklist. Diaphragmatic activity will be assessed by bedside diaphragmatic ultrasound. Patients will be positioned in a semi-sitting position (trunk inclination between 30 and 45°) to allow for better visualization of the right hemidiaphragm. The diaphragmatic assessment will include the measurement of inspiratory and expiratory thickness to calculate the diaphragmatic thickening fraction (intercostal approach) and the measurement of diaphragmatic excursion (subcostal approach) during the respiratory cycle. These measurements will be taken at rest. Diaphragmatic dysfunction will be defined by a thickening fraction strictly less than 20% and/or a diaphragmatic excursion strictly less than 1 cm at rest. Dyspnea will be assessed using a visual analog scale (VAS) ranging from 0 (no dyspnea) to 10 (maximum dyspnea). It will be evaluated within 24 hours following the weaning from ventilatory support and on the day the patient is deemed eligible for ICU discharge.

Conditions