The effect of pressure-controlled inverse ratio ventilation on lung protection in obese patients undergoing gynecological laparoscopic surgery

Abstract

Specific aim

To examine the effects of pressure-controlled inverse ratio ventilation (PCIRV) and volume-control ventilation (VCV) on arterial oxygenation, pulmonary function, hemodynamics, levels of surfactant protein A (SP-A), and tumor necrosis factor-α (TNF-α) in obese patients undergoing gynecological laparoscopic surgery.

Methods

Sixty patients, body mass index (BMI) ≥30 kg/m², scheduled for elective gynecological laparoscopic surgery were enrolled in the study. Patients were randomly allocated to receive either PCIRV with an inspiratory–expiratory (I:E) ratio of 1.5:1 (PCIRV group n = 30) or VCV with an I:E ratio of 1:2 (VCV group n = 30). Ventilation variables, viz. tidal volume (V _T), dynamic respiratory-system compliance (C _RS), driving pressure (ΔP = V _T/C _RS), arterial blood oxygen partial pressure/fraction of inspiration oxygen (PaO₂/FiO₂) and arterial blood carbon dioxide partial pressure (PaCO₂), were measured. Hemodynamic variables, viz. mean arterial pressure (MAP), heart rate (HR), and serum levels of SP-A and TNF-α, were also measured.

Results

When compared to patients in the VCV group, patients in the PCIRV group had higher V _T, dynamic C_RS, and PaO₂/FiO₂, and lower ΔP and PaCO₂ at 20 and 60 min after the start of pneumoperitoneum (p < 0.05). Patients in the PCIRV group had lower SP-A and TNF-α levels at 24 and 48 h after surgery than those in the VCV group (p < 0.05).

Conclusion

In obese patients undergoing gynecological laparoscopic surgery, PCIRV can improve ventilation, promote gas exchange and oxygenation, and is associated with decreased levels of SP-A and TNF-α. These effects demonstrate improved lung protection provided by PCIRV in this patient population.

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