Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access
Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc
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Case Report

Volume 8, Number 5, October 2017, pages 254-257

A Novel Technique for the Administration of Sub-Ambient Oxygen in the Operating Room


Figure 1.
Figure 1. The Datex-Ohmeda Aestiva 5 anesthesia machine that was used to deliver the sub-ambient oxygen gas mixture. The chain or proportioning mechanism (white arrow) which connects the oxygen and nitrous oxide flow meters was removed so that nitrous oxide could be administered with air to deliver an FiO2 less than 0.21. These modifications are not recommended by the manufacturer of the anesthesia machine.
Figure 2.
Figure 2. Standard oxygen blender for the administration of various concentrations of oxygen. The blender mixes oxygen (green hose) and air (yellow hose). In specific clinical scenarios, this blender can be modified to deliver a sub-ambient oxygen concentration to a hood by modification of the air hose so that it can be attached to a nitrogen tank. When this is done, it is mandatory to monitor the systemic oxygen saturation of the patient (pulse oximetry) and the inspired gas concentration to avoid morbidity and mortality from the administration of a hypoxic gas mixture.


Table 1. Oxygen Saturation and FiO2 During the Procedure
TimeFiO2Systemic oxygen saturation (%)
*After placement of pulmonary artery bands to limit pulmonary blood flow, the FiO2 was increased to 0.21.
Intraoperative - 15 min1373
Intraoperative - 30 min1594
Intraoperative - 45 min1495
Intraoperative - 60 min1684
Intraoperative - 75 min1576
Intraoperative - 90 min*2187
Intraoperative - 105 min2186
Intraoperative - 120 min2183