Role of lung ultrasound in assessing positive end expiratory pressure induced lung recruitment in patients on mechanical ventilation.

Abstract

Background: Lung ultrasonography is being increasingly used in mechanically ventilated patients to evaluate the lung aeration during incremental positive end expiratory pressure (PEEP) adjustments and to evaluate the weaning process from mechanical ventilation. The effects of PEEP may vary across different lung pathologies and may not consistently correlate with changes in lung aeration as assessed by lung ultrasound scores (LUSs).

Aim: To assess the role of lung ultrasonography in evaluating lung aeration during the application of PEEP in mechanically ventilated patients with various lung pathologies.

Methods: An observational study was conducted over 18 months in a tertiary care hospital. Patients of both genders, aged between 18-75 years, who had been admitted to the intensive care unit, and required mechanical ventilation, were studied. A standard ventilatory strategy was used and incremental levels of PEEP [5, 10, and 15 cm water (H₂O)] were applied. Baseline characteristics, including oxygen saturation (SpO₂), LUS, mean arterial pressure (MAP), heart rate (HR), and their changes with incremental PEEP levels, were recorded and analyzed.

Results: In this study, 45.9% of patients required a PEEP of 5 cm H₂O to achieve the endpoint of lung aeration (LUS of 0). In addition, 86.5% and 13.5% of patients reached the endpoint of lung aeration at PEEP levels of 10 and 15 cm H₂O, respectively. The proportion of patients with higher lung scores decreased significantly with increasing PEEP levels (P < 0.001 for 5 and 10 cm H₂O and P = 0.032 for 15 cm H₂O). SpO₂ increased significantly with higher PEEP levels (P < 0.001), confirming the effectiveness of PEEP in improving oxygenation. The results also revealed a significant increase in HR and a decrease in MAP following the application of higher PEEP levels.

Conclusion: Increasing PEEP levels in mechanically ventilated patients improves lung aeration, which can be effectively assessed using bedside lung ultrasonography.