Clinical use of a portable anesthesia machine with an oxygen concentrator in zoo-housed wild animals (Panthera onca, Ammotragus lervia, and Oryx dammah)

Field procedures in zoo-housed wild animals commonly rely on injectable anesthesia, but the application of inhalant anesthesia is often limited by the lack of reliable oxygen delivery systems. This case series evaluated the clinical utility of an oxygen concentrator–based portable anesthesia machine designed to provide inhalant anesthesia without compressed gas cylinders at Seoul Zoo. From May 2024 to May 2025, animals requiring diagnostic or therapeutic procedures under field conditions were prospectively enrolled, excluding cases managed with injectable anesthesia alone. A jaguar (Panthera onca), a Barbary sheep (Ammotragus lervia), and a scimitar-horned oryx (Oryx dammah) were anesthetized using an isoflurane vaporizer supplied solely by a high-output oxygen concentrator. Arterial blood gas analysis performed immediately after IM dart administration revealed reduced arterial oxygenation, with arterial partial pressure of oxygen ranging from 45.2 to 62.3 mmHg. During oxygen supplementation via the portable anesthesia system, arterial partial pressure of oxygen increased to 249–424 mmHg, and arterial partial pressure of carbon dioxide remained below 60 mmHg throughout anesthesia. One animal remained apneic after intubation and was supported with manual positive-pressure ventilation throughout anesthesia, which provided satisfactory ventilation and gas exchange, while the others maintained spontaneous breathing. Physiologic variables, including HR, RR, and mean arterial pressure (MAP), remained within acceptable limits, and recovery was uneventful in all cases. This case series illustrates that an oxygen concentrator-based portable anesthesia machine can effectively support stable inhalant anesthesia in the zoo. Further studies involving a broader range of species are warranted to confirm these findings and better define the clinical applicability of this approach.