Insufflation in minimally invasive surgery: Is there any advantage in staying low?

Minimally invasive repair of esophageal atresia with tracheoesophageal fistula (EA/TEF) and congenital diaphragmatic hernia (CDH) is feasible and confers benefits compared to thoracotomy or laparotomy. However, carbon dioxide (CO₂) insufflation can lead to hypercapnia and acidosis. We sought to determine the effect of lower insufflation pressures on patients' surrogate markers for CO₂ absorption - arterial partial pressure of CO₂ (PaCO₂), end tidal CO₂ (EtCO₂) and pH.

Single center retrospective review, including neonates without major cardiac anomaly. Selected patients formed 2 groups: Historical pressure (HP) group and low pressure (LP) group. We reported on the patients' preoperative characteristics that potentially confound the degree of CO₂ absorption or elimination. Outcome measures were perioperative PaCO₂, EtCO₂, arterial pH and anesthetic time.

30 patients underwent minimally invasive surgery for CDH and 24 patients for EA/TEF with similar distribution within the HP and LP group. For CDH patients as well as for EA/TEF patients, there were no significant differences in their preoperative characteristics or surgery duration comparing HP and LP groups. With a decrease in insufflation pressure in CDH patients, there were a significant decrease (p = 0.002) in peak PaCO₂ and an improvement in nadir pH (p = 0.01). For the EA/TEF patients, the decrease in insufflation pressure was associated with a significant decrease (p = 0.03) in peak EtCO₂. Considering all 54 patients, we found EtCO₂ to be highly significantly inversely correlated with pH and positively correlated with intraoperative PaCO₂ (p < 0.001). Baseline Hb was inversely correlated with mean EtCO₂ (p < 0.001).

With lower insufflation pressures, CDH patients had significantly improved hypercapnia and acidosis, while EA/TEF patients had significantly reduced EtCO₂. EtCO₂ was correlated with acidosis and hypercapnia.

Retrospective case control study.

Level III.