Novel strategy to decrease the fraction of inspired oxygen (FiO2) of an anesthetic circuit using a commercially available fish tank air pump: An in vitro study.

The aim of this study was to determine whether use of a commercially available fish tank air pump (FTAP) could predictably lower the fraction of inspired oxygen (FiO2) within an anesthetic circuit below the level of risk for O2 toxicity (FiO2 < 0.6). Three different anesthesia machines and an anesthesia ventilator were each outfitted with an FTAP. The FiO2 was measured at 4 different tidal volumes and 3 O2 flow rates at a set respiratory rate of 15 breaths per minute, and mean FiO2 was calculated. For each O2 flow rate and tidal volume combination, the FiO2 was reduced (FiO2 < 1). The FiO2 was more reliably decreased at lower O2 flow rates. A significant limitation of the study was the makeshift construction, leading to measurable leaks within the circuit. This technique could represent an economical and practical approach to providing ventilatory support in a resource limited setting. Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.