Abstract
We studied the relationship between arterial carbon dioxide tension (PaCO2) and fresh gas flow (FGF) during use of the Bain breathing circuit for Caesarean section anaesthesia. Thirty-one patients undergoing Caesarean section were anaesthetised using the Bain circuit with intermittent positive pressure ventilation. The PaCO2 were measured at FGF of 70ml·kg-1·min-1, 80 ml·kg-1min-1, and 100ml·kg-1·min-1. The FGF requirement to maintain a given PaCO2 during Caesarean section anaesthesia is the same as the requirements for nonpregnant subjects, despite the increase in carbon dioxide production associated with pregnancy. This is probably because the total FGF determined by body weight and given during Caesarean section anaesthesia is 15-20 per cent higher than nonpregnant levels, due to the weight gain associated with pregnancy. A FGF of 100 mlçkg-1 of pregnant weight/min maintains PaCO2 of 4.44 kPa predelivery, which is in the desirable range of PaCC2 during Caesarean section.
Résumé
On a étudié la relation entre la PaCO2 et le flot de gaz frais lors de l’utilisation du circuit de Bain lors d’une césarienne. Trente et une patientes devant subir une césarienne ont été anesthésiées utilisant le circuit de Bain avec une ventilation à pression positive intermittente. La PaCO2 a été mesurée avec un flot de gaz frais (FGF) de 70ml·kg-1·min-1 80 ml·kg-1·min-1 etl00ml·kg-1·min-1. Malgré une augmentation dans la production de CO2 lors de la grossesse, le flot de gaz frais requis afin de maintenir une PaCO2 donnée lors d’une césarienne demeure le même que celui requis pour des sujets non-gravides. Ceci est probablement dû au fait que le flot de gaz frais est déterminé par le poids corporel. Lors d’une césarienne, le flot de gaz frais est de 15 à 20 pour cent supérieur à celui d’une femme non-gravide à cause de l’augmentation du poids associee à la grossesse. Un flot de gaz frais de 100ml·kg-1·min-1; maintient une PaCO2 de 4.44 kPa avant l’accouchement, ce qui serait la valeur désirable de la PaCO2 lors d’une cesarienne.
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Moseley, H.S.L., Shankar, K.B. & Krishnan, A. Flow requirements for the Bain breathing circuit during anaesthesia for Caesarean section. Can Anaesth Soc J 33, 583–587 (1986). https://doi.org/10.1007/BF03014264
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DOI: https://doi.org/10.1007/BF03014264