Effects of heliox on respiratory management for a patient undergoing laparoscopic bariatric surgery

Purpose: The conflict between increased requirement for CO₂ clearance and reduced lung-thorax compliance during laparoscopic bariatric surgery poses a challenge in the ventilation of a bariatric patient's lungs. With its low density, heliox has been used in respiratory care to decrease airway resistance and airway pressure. We conducted a crossover pilot study to evaluate the effects of heliox on mechanical ventilation during bariatric surgical procedures. Methods: 11 of 13 consented patients completed the study protocol. Heliox 75/25 was used as a carrier gas during the phase I study, and an air/oxygen mixture with a FiO₂ of 0.3 was used during the phase II study. Data for peak inspiratory pressure, P_ETCO₂, and venous blood gas in each phase were compared. Results: Peak inspiratory pressure increased 14.8% from baseline after the onset of 15 mm Hg pneumoperitoneum. Breathing heliox reduced peak inspiratory pressure 8% from baseline (P = 0.033). No improvement in CO₂ clearance by breathing heliox was noted. Conclusions: It is unlikely that breathing heliox will confer any clinically significant value to lung management during laparoscopic bariatric procedures.