Pulmonary gas exchange and plasma lactate in horses with gastrointestinal disease undergoing emergency exploratory laparotomy: a comparison with an elective surgery horse population.

The research article discusses a study that sought to understand the relationship between pulmonary gas exchange, arterial lactate levels in horses with gastrointestinal illness, and the impact of emergency surgery on these factors compared to regular, elective surgery. It highlighted a lack of relationship between oxygen exchange and surgical outcomes, but found a significant correlation between high arterial lactate levels post-surgery and the risk of complications or death.

Aim and Methods

• The study aimed to study pulmonary gas exchange and arterial lactate levels in horses affected by gastrointestinal disease who undergo emergency exploratory laparotomy.
• The results were contrasted with those from horses who underwent elective surgery, with an aim to track these variables’ correlation with postoperative complications and mortality.
• Two sets of horses were selected for this – 50 who needed an emergency laparotomy for acute intestinal disease, and 20 healthy horses who were undergoing elective surgery while lying on their backs.
• Arterial blood gas analysis was carried out at pre-determined intervals on horses undergoing a standardized anesthetic protocol.
• The study then calculated the Alveolar-arterial oxygen gradient and used it and other factors to derive predictive factors for postoperative complications and death in colic horses.

Results

• The study found a broad variance in arterial oxygen tension (P(a)O(2)) levels across horses in both the groups.
• However, this measure significantly increased in the colic group following the exteriorization of the ascending colon.
• Despite the increase, there were no statistical differences in P(a)O(2) and the alveolar-arterial oxygen gradient between the groups. Further, these factors showed no correlation with the outcome for the horse.
• The researchers discovered that arterial lactate levels in recovery that was ≥ 5 mmol/L hinted at a 2.25 times greater relative risk of complications, and lactate levels of ≥ 7 mmol/L were associated with a relative risk of death that was 10.5 times higher.

Conclusions

• The researchers concluded that horses suffering from colic in this population were not more likely to be hypoxemic than their elective surgery counterparts. That is, their gas exchange was not impaired on a greater scale relative to the control group of horses.
• The study drastically underlined the significance of arterial lactate levels sampled immediately after anesthetic recovery as a predictive tool for anticipating postoperative complications and even death.