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

AIM: 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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

TYPE OF STUDY: Retrospective case control study.

LEVEL OF EVIDENCE: Level III.