Modified Lung Ultrasound Examinations in Assessment and Monitoring of Positive End-Expiratory Pressure-Induced Lung Reaeration in Young Children With Congenital Heart Disease Under General Anesthesia*

Abstract

Objectives: Lung ultrasound can reliably diagnose pulmonary atelectasis. The object of this study is to determine the most efficient region to assess changes in atelectasis in children with congenital heart disease under general anesthesia. Design: Randomized controlled trial. Setting: Operating room at university-affiliated children’s hospital. Patients: Children between 3 months and 3 years old, scheduled for elective congenital heart disease surgery under general anesthesia. Interventions: Forty children with congenital heart disease were randomly allocated to either a 5 cm H2O positive end-expiratory pressure group or a standard therapy control group. Measurements and Main Results: Preoperative lung ultrasound was performed twice in each patient—after 1 and 15 minutes of mechanical ventilation. Atelectatic areas and B-lines were compared between two examinations. Different ultrasound regions were evaluated using Bland-Altman plots. The occurrence rate of atelectasis was much higher in inferoposterior lung regions (Scans 4–6) than in anterior and lateral regions (Scans 1–3). The median (interquartile range) lung ultrasound scores were lower in the positive end-expiratory pressure group than in the control group after treatment: 8 (3.3–9.8) versus 13 (8.3–17.5; p < 0.001). The atelectatic area was significantly decreased after treatment in the positive end-expiratory pressure group: 128 mm2 (34.5.5–213.3 mm2) versus 49.5 mm2 (5.3–75.5 mm2; p < 0.001). Bland-Altman plots revealed concordance between measurements in Scans 1–6 and those in Scans 4–6. In the posterior axillary line regions, changes in atelectatic area were significantly larger in the positive end-expiratory pressure group than in the control group (p = 0.03, 0.007, and 0.018). Conclusions: Lung ultrasound in inferoposterior lung regions may be more likely to reflect changes in atelectasis and save examination time; 5 cm H2O positive end-expiratory pressure may be useful in lung reaeration and can reduce, but not eliminate, atelectasis in children with congenital heart disease.

Lung ultrasound evaluation of incremental PEEP recruitment maneuver in children undergoing cardiac surgery

“…Several studies have recently reported that using incremental PEEP results in improved lung aeration in ventilated patients with acute lung injury and ARDS 14,30‐32 . Our study findings also indicated that the iPEEPRM, starting from 0 cmH 2 O and increasing to 15 cmH 2 O, could significantly reduce atelectasis and improve lung aeration in children with CHD, as assessed using ultrasound scans, and was better than 5 cmH 2 O PEEP alone in reducing atelectasis 12 …”

“…As early as 1963, Bendixen et al 11 described the physiological rationale of a lung recruitment maneuver during anesthesia using an anesthesia bag for 15 seconds, which normalized arterial oxygenation and lung compliance for a short time. Our previous study also confirmed that 5 cmH 2 O PEEP could effectively reduce, but not eliminate, atelectasis in children with CHD assessed using lung ultrasound 12 …”

“…Therefore, the routine use of SI recruitment maneuvers is not justified, especially for patients with ARDS 27,28 . In our previous study, we found that a fixed level PEEP (5 cmH 2 O) recruitment maneuver could improve lung re‐aeration and reduce atelectasis in children with CHD; however, 5 cmH 2 O PEEP was not sufficient to eliminate atelectasis entirely 12 . High‐level PEEP may cause hemodynamic instability and increase the risk of barotrauma and ventilator‐induced lung injury 29 .…”

“…We assumed an 82.5% occurrence rate for atelectasis, as previously reported, 12 and that the iPEEPRM would reduce this rate to 44%. With an alpha error of .05, a power of 80%, and allowing for a dropout rate of 5%, a sample size of 21 patients was required for this study.…”

“…In recent years, lung ultrasound has been widely used to detect lung diseases at the bedside, including lung edema and atelectasis. Furthermore, lung ultrasound can also be used to monitor changes in lung aeration and guide recruitment maneuvers continuously and dynamically 12,19 . Therefore, the aim of our study was to explore the effects of the iPEEPRM on atelectasis and lung aeration in children undergoing CHD surgery using lung ultrasound.…”