Lung Ultrasound and Non-Invasive Ventilation Outcome in Acute Respiratory Failure

Abstract

Objective: This study aimed to assess the diaphragmatic dysfunction in critically ill non-intubated patients admitted to respiratory critical care unit with acute respiratory failure.

Methods: This was a prospective study conducted on 200 mechanically ventilated patients. The following data were collected: demographic characteristics, anthropometric measurements. Disease severity and hemodynamics. In addition, ICU length of stay, duration mechanical ventilation, outcome and duration of hospital stay.  Besides, parameters of MV like (PaO2 / FiO2 Ratio), and respiratory rate were noticed. The laboratory workup included arterial blood gases, Na+, K+, Mg++, Ca++, PH, PCO2, HCO3-. The ultrasound was performed before and after weaning and included the diaphragmatic excursion and diaphragmatic thickness traction. The patients were split into two categories regarding their reaction to weaning attempts: Category A represented successful weaning. Category B represented unsuccessful weaning followed by reintubation and mechanically ventilated.

Results: The weaning success was reported for 123 patients (61.5%) and mortality reported for 28 patients (14.0%). Weaning success was associated with male gender, younger age and slightly higher BMI. Obstructive airway disease showed significant increase in success than failure (25.2% vs 11.7% respectively). Weaning failure was significantly associated increased septic shock and pneumonia. The muscle thickness in inspiration was significantly increased in success than failure (25.56 vs 24.08 respectively). DE before weaning was the most sensitive indicator at cut-off value > 15 followed by DE after weaning at cutoff value >17; while DTF after weaning was more sensitive than DTF before weaning (93.55% and 80.65% respectively) at cutoff points > 20.4 and > 18.5, respectively.

Conclusion: Assessment of DTF and DE by diaphragm ultrasound is an easy to obtain new weaning index that can be a bedside method in clinical practice with promising predictors of weaning success or failure before and after weaning.