Acid-base and electrolyte alterations associated with salivary loss in the pony.

The study aimed to investigate the impacts of salivary loss on the balance of acid and base in the blood, as well as its effects on the amount of different electrolytes in ponies. It found salivary depletion led to transient metabolic acidosis due to bicarbonate loss in saliva, followed by metabolic alkalosis likely due to kidney compensation. It also discovered a decrease in chloride and sodium levels, while potassium was only slightly affected because of dietary supplements.

Methods and Study Participants

• The researchers conducted the experiment on a sample of 6 ponies. These ponies underwent a surgical procedure to acquire esophageal fistulas, which is an abnormal connection between the esophagus and other body parts.
• To evaluate the effects of salivary depletion, this group of ponies was fed a pelleted diet through an esophagostomy tube, a technique of delivering food directly to the esophagus after the creation of a fistula.

Control Group

• Three additional ponies were used as controls. These control ponies also received the identical pelleted diet, but they were fed nasogastrically, or through the nose into the stomach.
• Over the course of 15 days, the researchers found that the acid-base and electrolyte values within the control group remained within normal ranges.

Results and Findings

• In the fistula-bearing ponies, however, hypochloremia (low levels of chloride) and hyponatremia (low levels of sodium) developed over the same period.
• The serum potassium concentrations were only marginally depleted, due to dietary replacement.
• Yet, salivary depletion in these ponies initially led to metabolic acidosis due to the loss of bicarbonates in saliva, a condition where there is too much acid in the body fluids.
• Subsequently, metabolic alkalosis developed—a condition where the body fluids have excess base (alkali) due to the kidney’s compensation for electrolyte imbalances.

Discussion

• The researchers found that salivary electrolytes in these ponies were present in high concentrations possibly because of increased salivary flow rates.
• The saliva initially had high levels of sodium, chloride, and potassium. However, salivary sodium and chloride concentrations decreased progressively over a 5-day collection period.
• The observed electrolyte savings were attributed to influences from the diet and hormonal control of electrolyte transport in salivary ducts.
• Furthermore, the authors discussed possible therapeutic interventions for the correction of the identified alterations in acid-base balance and electrolyte levels.