Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Comparative Study
Contemporary anesthesia ventilators incur a significant "oxygen cost".
Anesthesia ventilators use oxygen or oxygen/air mixtures to drive the bellows during controlled ventilation. As a practitioner may find himself in a situation that the only available oxygen source is a compressed oxygen cylinder, it is important to know the oxygen consumption of anesthesia ventilators during controlled ventilation. ⋯ Machine-driven mechanical ventilation incurs a significant "oxygen cost." We show that the amount of oxygen consumed by mechanical ventilation with contemporary anesthesia ventilators is influenced by patient-dependent factors and may greatly exceed the amount of oxygen delivered to the patient.
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Neuraxial blockade is known to have a sedative effect, decreasing the need for inhalational and iv anesthetic agents. The purpose of the present study was to quantify the sedative effect of spinal anesthesia and to determine the time of maximum sedation. ⋯ In this elderly patient population, spinal anesthesia induced changes in the processed electroencephalogram with reduction in PSI and OAA/S scores. The reduction in afferent input to the reticular activating system could possibly explain the sedation that has been observed and the reduction in the PSA scores.