Interstitial pH and pressure in the dependent biceps femoris muscle of laterally recumbent anesthetized horses.

The study analyzes the interstitial pressure and pH in the biceps femoris muscle of horses under anesthesia, lying in a sideways position. It found that anesthesia led to a decrease in pH and increased pressure, which may implicate a reduction in muscle blood flow.

Methodology

• The pilot study included ten horses placed under anesthesia and kept in laterally recumbent positions.
• Interstitial pressure and pH, the measures of the fluid between the cells of the biceps femoris muscle, were recorded at intervals from 30 to 180 minutes post-anesthesia.

Findings

• The results showed that average interstitial pressure in the muscle was around 19.70 +/- 0.15 mmHg.
• This level of pressure has been previously associated with a decrease in muscle perfusion, or the flow of blood through the muscle tissue.
• In a subset of six horses, the average interstitial pH decreased from 7.07 +/- 0.30 to 6.73 +/- 0.21 between 45 to 150 minutes of anesthesia.
• A decrease in pH indicates an increase in acidity, which could further indicate a lack of oxygen or presence of metabolic waste, a condition referred to as ‘acidosis’.

Conclusion

• The study concluded that this evidence suggests there is a circulatory compromise to structures within the same compartment, or intracompartmental structures, within the muscle during anesthesia in horses.

Significance

• This research draws attention to the potential negative impacts of anesthesia on muscle perfusion in horses, particularly for lengthy surgical or diagnostic procedures where animals are anesthetized for extended periods.