Influence of modified open lung concept ventilation on the cardiovascular and pulmonary function of horses during total intravenous anaesthesia.

This research investigates how the modified open lung concept (mOLC), a particular technique of maintaining clear lung function, impacts the heart and lung functions of horses anesthetized intravenously. The findings reveal that the application of this technique leads to higher oxygen levels and lower average blood pressure in horses as compared to other techniques applied during the study.

Research Details

• The scientists conducting the study aimed to test how a strategy called the modified Open Lung Concept (mOLC) impacted the cardiovascular and pulmonary performance in horses undergoing total intravenous anesthesia. They wanted to ascertain whether mOLC could positively affect oxygenation and blood pressure in this context.
• To carry out the study, 42 warm blood horses, classified as either class 1 or class 2 by the American Society of Anesthesiologists, were divided into three groups based on which method of respiration they would receive: mOLC, Intermittent Positive-Pressure Ventilation (IPPV), or standard, spontaneous breathing. The purpose of this was to gain comparative results between the three different techniques.

Anesthesia Details

• The horses were sedated (with 0.8 mg/kg xylazine), put to sleep (induced with 2.2 mg/kg ketamine and 0.05 mg/kg diazepam) and kept asleep (maintained with a cocktail of 1.4 mg/kg/hr xylazine, 5.6 mg/kg/hr ketamine, and 131.1 mg/kg/hr guaifenesin) under total intravenous anesthesia (TIVA). In addition to this, the horses were also given 35% oxygen to breathe.
• The uniformity in anesthesia administration across all animals ensured that any differences observed could be attributed to the ventilation technique used, rather than variations in anesthesia.

Data Collection and Analysis

• Important indicators of cardiovascular and pulmonary health such as heart rate, respiratory rate, mean arterial blood pressure (MAP), as well as blood pH and the partial pressures of oxygen and carbon dioxide were monitored and recorded at 10-minute intervals from 20 to 90 minutes into the anesthesia.
• The data was then analyzed using a factorial analysis of variance and a Tukey’s post hoc test with a statistical significance set at 5%.

Findings and Conclusion

• The results revealed that horses in the mOLC group showed higher oxygen pressure in their arterial blood and a lower mean arterial pressure compared to those in the IPPV and spontaneous breathing groups. This suggested that the mOLC technique of ventilation was more effective in maintaining optimal oxygenation and blood pressure during intravenous anesthesia in horses.
• These results suggest that the mOLC method of ventilation could be a preferred technique while performing total intravenous anesthesia in horses. Additional studies are recommended to validate these findings further.