A comparison of the effects of lung protective ventilation and conventional ventilation on the occurrence of atelectasis during laparoscopic surgery in young infants: a randomized controlled trial

Abstract

Objective: This study utilized lung ultrasound to investigate whether lung protective ventilation reduces pulmonary atelectasis and improves intraoperative oxygenation in infants undergoing laparoscopic surgery.

Methods: Eighty young infants (aged 1-6 months) who received general anesthesia for more than 2 h during laparoscopic surgery were randomized into the lung protective ventilation group (LPV group) and the conventional ventilation group (control group). The LPV group received mechanical ventilation starting at 6 mL/kg tidal volume, 5 cmH₂O PEEP, 60% inspired oxygen fraction, and half-hourly alveolar recruitment maneuvers. Control group ventilation began with 8-10 mL/kg tidal volume, 0 cmH₂O PEEP, and 60% inspired oxygen fraction. Lung ultrasound was conducted five times-T1 (5 min post-intubation), T2 (5 min post-pneumoperitoneum), T3 (at the end of surgery), T4 (post-extubation), and T5 (prior to discharge from the PACU)-for each infant. Simultaneous arterial blood gas analysis was performed at T1, T2, T3, and T4.

Results: Statistically significant differences were observed in pulmonary atelectasis incidence, lung ultrasound scores, and the PaO₂, PaCO₂, PaO₂/FiO₂ ratios at T2, T3, and T4. However, at T5, no statistically significant differences were noted in terms of lung ultrasound scores (4.30 ± 1.87 vs. 5.00 ± 2.43, 95% CI: -1.67 to 0.27, p = 0.153) or the incidence of pulmonary atelectasis (32.5% vs. 47.5%, p = 0.171).

Conclusion: In infants aged 1-6 months, lung protective ventilation during laparoscopy under general anesthesia significantly reduced the incidence of pulmonary atelectasis and enhanced intraoperative oxygenation and dynamic lung compliance compared to conventional ventilation. However, these benefits did not persist; no differences were observed in lung ultrasound scores or the incidence of pulmonary atelectasis at PACU discharge.

Clinical trial registration: http://www.chictr.org.cn/, identifier: ChiCTR2200058653.

Keywords: infant; laparoscopy; lung protective ventilation; positive end-expiratory pressure; pulmonary atelectasis; recruitment maneuvers; ultrasonography.

Figure 1

The study protocol and ultrasound lung examination region is shown. From left to right are scores: 0, 0 to 2 B lines; 1, at least three B lines or one or multiple small subpleural consolidations separated by a normal pleural line; 2, multiple coalescent B lines or multiple small subpleural consolidations separated by a thickened or irregular pleural line; 3, consolidation or small subpleural consolidation of more than 1 cm x 2 cm. One yellow arrow, pleural line; one white arrow, A line; two white arrows, B line; three white arrows, subpleural consolidations; white arrowheads, consolidation. Significant atelectasis is determined if any region had a consolidation score of 2. RMs, recruitment maneuvers, PEEP, positive end-expiratory pressure. T1, 5 min post-intubation, T2, 5 min post-pneumoperitoneum, T3, at the end of surgery.

Figure 2

Operational definitions of postoperative pulmonary complications (23).

Figure 3

CONSORT study flow diagram.

Figure 4

Comparison of lung ultrasound scores at different time points between the two groups. Ns, no significance. ** indicates statistical significance.