N14A-T015 TITLE: Anesthesia Ventilator for Atlantic Bottlenose Dolphins and California Sea Lions

TECHNOLOGY AREAS: Biomedical

ACQUISITION PROGRAM: Explosive Ordnance Disposal Underwater Programs (SEA00 EOD/CREW-2)

OBJECTIVE: Develop an anesthesia ventilator for Atlantic bottlenose dolphins and California sea lions that can mimic the breathing patterns of these unique animals, and is functionally compatible with commercially available human and large animal veterinary gas anesthesia systems.

DESCRIPTION: The U.S. Navy uses Atlantic bottlenose dolphins (Tursiops truncatus) and California sea lions (Zalophus californianus) in the Fleet�s operational Marine Mammal Systems to protect harbors and Navy assets, detect and/or mark underwater mines, and locate and attach recovery hardware to underwater objects. To contribute to the maintenance of the fitness of these marine mammals for duty and the readiness of the U.S. Navy Marine Mammal Systems, the U.S. Navy is interested in developing a ventilator for use when anesthetizing Atlantic bottlenose dolphins and California sea lions. Ensuring adequate ventilation of the marine mammal patient is one of the key challenges to the anesthetist. Marine mammal pulmonary anatomy, cardiovascular physiology, and central nervous system control over ventilation are often unique in comparison to terrestrial animals. Also challenging for the anesthetist is the effect of removing the patient from the water and its buoyant effects. This is primarily an issue with anesthetized dolphins. Add to this that most anesthetics cause mild to moderate respiratory depression and the need for reliable and effective ventilation becomes obvious in this group of animals. Most anesthesia ventilators are designed for humans and have some use with small mammals (<140 kg) (1). Most anesthesia ventilators do not include newer modes of ventilation and some cannot develop high enough inspiratory pressure, flow or positive end expiratory pressure to ventilate large mammals (2). Few ventilators are designed for large mammals, all of which fail to resolve ventilation perfusion mismatch and significantly reduce cardiac output, and none of which meet current anesthesia ventilator standards (3, 4).

PHASE I: Conceptualize and design an anesthesia ventilator for Atlantic bottlenose dolphins and California sea lions. The anesthesia ventilator should utilize commercially available components and operate in a manner that facilitates a normal physiologic state in these animals in the face of anesthesia and their unique pulmonary mechanics (5-14). The anticipated ventilator support time is 4-5 hours in a conventional ventilation mode (15-21). Respiratory rates should be adjustable from 0-16 breaths per minute. The target tidal volume is 3-15 liters. Inspiratory/expiratory volumes need to be adjustable to allow for variable rates of flow over time. Inspiratory volumes should be delivered in 0.5 � 4 seconds while expiratory volumes should be exchanged in 0.5 � 15 seconds. System requirements are that peak inspiratory pressures should range from 0 � 50 centimeters of water. The user interface should display the respiratory rate, inspiratory time, peak inspiratory/airway pressure, and the inspiratory to expiratory ratio. The ventilator should be functionally operable with commercially available human and large animal veterinary gas anesthesia systems. Apneustic plateau and airway pressure release ventilation (APRV) modes are desired capabilities in this ventilator. Magnetic resonance imaging (MRI) compatible/conditional system capability is also desired (22, 23). Collaboration with a Boarded Veterinary Anesthesiologist experienced with anesthetizing both California sea lions and Atlantic bottlenose dolphins is recommended.

PHASE II: Based on the Phase I design, build a prototype anesthesia ventilator for Atlantic bottlenose dolphins and California sea lions and demonstrate its functionality with commercially available human and large animal veterinary gas anesthesia systems using a mechanical model. Testing of the initial system on an animal model is also desired. Collaboration with a Boarded Veterinary Anesthesiologist experienced with anesthetizing both California sea lions and Atlantic bottlenose dolphins is recommended.

PHASE III: Build an operable gas anesthesia system incorporating the Atlantic bottlenose dolphin and California sea lion anesthesia ventilator prototype. Demonstrate the operability and safety of the complete system on marine mammals. Document and report the physiologic parameters of the animal while anesthetized to demonstrate and validate system efficacy. Demonstrate the system's capability and efficacy to ventilate in standard, apneustic plateau, and APRV modes. Components of the gas anesthesia and ventilator system will be constructed to meet MIL-STD-810G as it applies to use of deployable military medical equipment. Magnetic resonance imaging (MRI) compatible/conditional system capability is desired. Collaboration with a Boarded Veterinary Anesthesiologist experienced with anesthetizing both California sea lions and Atlantic bottlenose dolphins is recommended.

Efforts should lead to development of a product that meets appropriate standardization requirements or FDA approval, and focus on technology transition, preferably commercialization. The small business should have plans to secure funding from non�STTR government sources and/or the private sector to develop or transition the technology into a viable product for sale in the military and/or private sector markets. There are currently no standards for safety and functionality of veterinary medical equipment. Suppliers of anesthesia machines for human patients voluntarily agreed to comply with standards set by ASTM International (known until 2001 as the American Society for Testing and Materials (ASTM)) since 1988. Several other organizations have worked to assure a degree of safety and functionality of equipment, but are still somewhat limited in controlling for all applications. No single standardization has yet arisen, but the American National Standards Institute (ANSI), ASTM and CEN (the European Community for Standardization) are working together to promote interoperability and consumer protection, while the International Organization for Standardization (ISO) works toward a universal, internationally accepted set of standards.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: A ventilator developed with the above listed capabilities would have application in the care of captive and managed populations of these animals world-wide (e.g. aquariums, marine parks) and may have applications for alternative modes of ventilation in other mammalian species.

REFERENCES:
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19. S. Ridgway and J. Simpson, "Anesthesia and restraint for the California sea lion, Zalophus californianus" Journal of the American Veterinary Medical Association, Vol. 155, pp. 1059-1063 (1969).

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23. C. Gooden, "Anesthesia for Magnetic Resonance Imaging" Curr. Opin. Anesthesiol., Vol. 17, pp. 339-342 (2004).