Ultrasonographic comparison of the diaphragm function in critically ill patients with volume and pressure modes

Mechanical ventilation and the effect of respiratory muscle unloading on the diaphragm causes atrophy of the diaphragmatic muscle. Aim of the present study was to evaluate the ultra sonographic indices of diaphragm contractile activity (respiratory excursion and thickening) during mechanical ventilation with Bilevel Positive Airway Pressure (BiPAP) and Synchronized intermittent mandatory ventilation (SIMV), widely used modes in critically ill patients [1]. Eligible patients admitted to the ICU who met criteria equally divided in 2 groups; 1) BiPAP (n = 20) and 2) SIMV (n = 20). Cases of thoracic/gastric/ esophageal surgery, patients with the history of neuromuscular disorders, and who weaned from mechanical ventilation during the first 48 h after ultra sonographic recording were excluded. The right hemidiaphragm was evaluated by B- and M-mode ultrasonography to record diaphragmatic excursion (DE) and thickening fraction (DTF) [2]. In the BiPAP group, DTF values in the first, third and seventh days were 39 ± 9%, 27.8 ± 7.4% and 22 ± 6.5% and diaphragmatic excursion (DE) were 2 ± 0.31 cm, 1.35 ± 0.19 cm and 1.13 ± 0.14 cm respectively. First, third and seventh days DTF values in the SIMV group, were 32 ± 5.1%, 25 ± 4.2% and 21.5 ± 4.47%; and DE were 1.9 ± 0.32 cm, 1.38 ± 0.26 cm and 0.95 ± 0.23 cm respectively. The DTF and DE values reduced significantly during the time in both groups (P value