Pressure-controlled inverse ratio ventilation improves gas exchange in obese children undergoing laparoscopic surgery: a randomized controlled study.

Background: Obese children undergoing laparoscopic surgery frequently experience high end-tidal carbon dioxide partial pressure (P _ET CO ₂ ) and respiratory acidosis. This study aimed to investigate the effects of pressure-controlled inverse ratio ventilation (IRV) with an inspiratory to expiratory ratio (I:E) of 1.5:1 on obese children undergoing laparoscopic surgery.
Methods: Eighty children undergoing laparoscopic surgery were randomly assigned to either the IRV group (I:E=1.5:1) or the control group (I:E=1:1.5). The lungs were mechanically ventilated following tracheal intubation. The children underwent pressure-controlled ventilation with an I:E ratio of 1.5:1 or 1:1.5. Respiratory mechanics, hemodynamic values, and ventilation-related side effects were recorded.
Results: Thirty minutes after establishing CO ₂ pneumoperitoneum, the IRV group exhibited significantly higher tidal volume (Vt) and arterial partial pressure of oxygen (PaO ₂ ) compared to the control group (97.6 ± 6.6 vs. 93.2 ± 8.0 ml, 283 ± 54 vs. 247 ± 40 mmHg, respectively) ( P < 0.01). Furthermore, PaCO ₂ was significantly lower in the IRV group than in the control group (41.4 ± 5.8 vs. 45.5 ± 5.7 mmHg, P =0.002). The incidence of intra-operative hypercapnia was significantly decreased in the IRV group (25% vs. 42.5%, P =0.03).
Conclusion: Pressure-controlled IRV can reduce the incidence of hypercapnia, increasing Vt, and thereby improving CO ₂ elimination in obese children undergoing laparoscopy. This ventilation technique significantly improves gas exchange in this patient population. (Registration number: ChiCTR2000035589).
Competing Interests: None.
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