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Hyperbaric nitrous oxide as a sole anesthetic agent in humans
G B Russell1, M T Snider, R B Richard
1Department of Anesthesia, Pennsylvania State University College of Medicine, University Hospital, Milton S. Hershey Medical Center, Hershey 17033.
Anesthesia and Analgesia
|March 1, 1990
Summary
Nitrous oxide (N2O) anesthesia in a hyperbaric environment caused significant physiological changes in volunteers. Maintaining a stable state proved challenging due to tachypnea, tachycardia, and blood pressure increases.
Area of Science:
- Anesthesiology
- Hyperbaric Medicine
- Physiology
Background:
- Nitrous oxide (N2O) is a long-established anesthetic agent.
- Its high Minimum Alveolar Concentration (MAC) necessitates hyperbaric conditions for general anesthesia.
- Limited data exists on human physiological responses to hyperbaric N2O.
Purpose of the Study:
- To investigate human physiological responses to N2O anesthesia in a hyperbaric environment.
- To document the effects of prolonged N2O exposure at 2 ATA.
Main Methods:
- Eight male volunteers were studied.
- Anesthesia was induced using N2O only at 2 ATA (1520 mm Hg) for 2-4 hours.
- N2O partial pressures ranged from 836 to 1368 mm Hg.
Main Results:
- The anesthetic state was characterized by tachypnea, tachycardia, and elevated systemic blood pressure.
- Pupil dilation (mydriasis) and sweating (diaphoresis) were observed.
- In some instances, clonus and opisthotonus occurred.
- Maintaining physiological stability was difficult.
Conclusions:
- Hyperbaric N2O anesthesia induces significant and sometimes unpredictable physiological changes.
- Further research is needed to understand and manage these responses for safe clinical application.