Impact of nitrous oxide on the haemodynamic consequences of venous carbon dioxide embolism An experimental study

BACKGROUNDNitrous oxide (N2O) is still considered an important component of general anaesthesia. However, should gas embolisation occur as result of carbon dioxide (CO2) pneumoperitoneum, N2O may compromise safety, as the consequences of a gas embolus consisting of a combination of CO2 and N2O may be more severe than CO2 alone.OBJECTIVEThis experimental study was designed to compare the cardiopulmonary consequences of gas embolisation with a N2O/CO2 mixture, or CO2 alone.DESIGNExperimental study.SETTINGResearch Institute Against Digestive Cancer laboratory, Strasbourg, France.ANIMALSSeven Large-White pigs receiving standardised inhalation anaesthesia.INTERVENTIONSEach animal, acting as its own control, was studied in two successive experimental conditions - intravenous gas injections of 2mlkg(-1) of 100% CO2 and 2mlkg(-1) of a gas mixture consisting of 10% N2O and 90% CO2.MAIN OUTCOMES MEASURESHaemodynamic and ventilatory consequences of embolisation with the gases(.)RESULTSWe found that the haemodynamic (heart rate, mean arterial blood pressure, central venous pressure, mean pulmonary artery pressure, pulmonary artery occlusion pressure and transoesophageal echocardiography parameters) and ventilatory (arterial oxygen saturation, end-tidal CO2 concentration and mixed venous oxygen saturation) consequences of embolisation with either 100% CO2 or 10% N2O with 90% CO2 were similar.CONCLUSIONThe findings of this study may alleviate concerns that the use of N2O, as a part of a balanced general anaesthesia technique, may have greater adverse consequences should embolisation of pneumoperitoneal gas containing N2O occur.