Hemodynamic effects of helium vs carbon dioxide pneumoperitoneum in an experimental model of acute heart failure

Background  The systemic absorption of carbon dioxide (CO₂) during abdominal insufflation can lead to hypercarbia and acidosis, which contribute to the systemic hemodynamic effects of the pneumoperitoneum (PnP). In several animal and clinical studies, the use of helium (He) as a substitute for CO₂ prevented the development of hypercarbia. One of the common comorbid conditions in which the use of a CO₂ PnP may cause adverse effects is heart failure. The aim of our study was to evaluate and compare the hemodynamic effects of CO₂ and He PnP in an animal model of acute heart failure (AHF). Methods  Hemodynamic and blood gas parameters were measured in 10 domestic pigs during two periods of He and CO₂ insufflation of 30 min duration each, with a 30-min stabilization period between insufflations. The model of AHF was created by sodium pentobarbital injections, and measurements were repeated with both CO₂ and He PnP. The animals were ventilated with constant minute ventilation. Results  Cardiac output had a tendency to decrease during PnP, but these changes were more pronounced with CO₂ PnP in normal the heart (from 2.84±0.65 to 2.18±0.68 L/min, p=0.06) and with He PnP during AHF (from 1.78 ±0.49 to 1.32±0.34 L/min, p=0.016). Systemic vascular resistance increased in every insufflation, but this elevation was not statistically significant. CO₂ and He insufflation caused significant increase of PaCO₂ in the nonfailed heart. During AHF, He insufflation did not elevate PaCO₂. Conclusions  In an experimental model of acute heart failure, insufflation with He did not have any advantage over CO₂. The hemodynamic response to CO₂ and He PnP during normal conditions and under conditions of failed cardiac function support the hypothesis that the hemodynamic response to PnP is a result of a combination of pressure and CO₂ absorption; Furthermore, it appears that increased intraabdominal pressure is the more crucial factor. Online publication: 7 May 2001 Presented in poster format at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), San Antonio, TX, USA. 24–27 March 1999