Anaesthesia and intensive care
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Anaesth Intensive Care · Jun 1995
Comparative StudyMaxima and Bain breathing systems compared in controlled ventilation.
The Maxima is a new universal breathing system, which, despite its being valveless, functions with near maximal efficiency in spontaneous and controlled ventilation. It was compared to the Bain system in controlled ventilation by adjusting fresh gas flows (VF) to achieve an end-tidal CO2 of 5% in 40 patients aged from one to seventy-six years. They received a combined regional and general anaesthetic technique. ⋯ The mean VF requirement for the Bain system was greater by 45%. Of these forty patients, the results from the twenty-four adult patients weighing 50 kg or more gave the respective VF requirements for the Maxima and Bain systems of 52 and 71 ml.min-1.kg-1. In a separate study using twenty-nine patients, the fractional utilization of fresh gas (FU) (or VAe/VF where VAe = effective alveolar ventilation) in the Maxima and Bain systems was shown to be 0.94 and 0.71 respectively.