An implementation of apneustic anesthesia ventilation in the horse: comparison with conventional mechanical ventilation.

The study investigates the cardiopulmonary impacts of apneustic anesthesia ventilation (AAV) versus conventional mechanical ventilation (CMV) in anesthetized horses in dorsal recumbency. It was found that both ventilation modes provided satisfactory oxygenation, with AAV showing higher dynamic compliance index and lower venous mixture, revealing AAV as a potentially more efficient ventilation mode.

Introduction

• The research takes a closer look at two methods of ventilation used in anesthetized horses – apneustic anesthesia ventilation (AAV) and conventional mechanical ventilation (CMV).
• The idea was to compare the cardiopulmonary effects of these ventilation methods and determine which one is better or if they performed similarly.

Methodology

• A total of 10 horses from a university-owned herd were used for the study. The methodology involved administering appropriate medications to the horses and then carrying out the ventilation exercises.
• After administering anesthesia to the horses, they were orotracheally intubated and placed dorsal recumbency. Anesthesia was maintained with isoflurane in oxygen and horses were ventilated with either AAV or CMV for an hour according to predefined criteria.
• Measurements were taken at baseline, 30 minutes, and 60 minutes into the ventilation process.

Findings

• The study revealed that there were significant effects of the ventilation mode on one or more time points, specifically for respiratory rate, arterial and end-tidal CO tensions, arterial pH, mean airway pressure, respiratory system dynamic compliance index, venous admixture, mean pulmonary artery pressure, and systemic vascular resistance.
• No significant differences were observed between the modes for tidal volume, the fraction of inspired oxygen, oxygen pressure in arterial blood, arterial hemoglobin saturation, alveolar dead space, heart rate, mean arterial pressure, cardiac index, stroke volume index, oxygen delivery index, oxygen extraction ratio, and dobutamine administration.

Conclusion

• The research concluded that both AAV and CMV provided adequate oxygenation to the anesthetized horses with minimal supplemental oxygen, indicating that both methods are effective.
• However, compared to CMV, AAV resulted in a higher dynamic compliance index (a measure of the lungs’ ability to expand and contract), and a lower venous admixture (a measure of the mixture of ventilated and deoxygenated blood).
• Even though the mean airway pressure was higher with AAV, the cardiovascular effects were not significantly different for both the modes suggesting both AAV and CMV are safe and effective for use.
• Therefore, the study supports the need for further trials of AAV in anesthetized horses to fully validate its efficiency.