Research Update: Determining the significance of blood chemistry changes in dogs with GI foreign bodies

In this retrospective study from a veterinary teaching hospital, the medical records of 138 dogs (1997-2000) with a surgically removed gastrointestinal (GI) foreign body were reviewed to determine whether acid-base or electrolyte abnormalities were related to the site or type of foreign body. All dogs were seen in an urban emergency clinic setting.

The mean age of the dogs was 3.8 years, and Labrador retrievers were most often represented (22 cases). The duration of vomiting (median = 48 hours) was noted in 124 dogs. Imaging (plain abdominal radiography, abdominal ultrasonography, or upper GI contrast study) was performed in all the cases.

The location of the foreign body during celiotomy was most frequently in the stomach (50%) or jejunum (27.5%), and the foreign body was most commonly linear (36.2%). Resection and anastomosis were performed in 28% of the cases. After surgery, one dog died, three dogs had complications requiring another surgery (peritonitis, dehiscence), and eight dogs had complications not requiring surgery (pancreatitis, pneumonia, GI motility problems, seroma formation).

The most common biochemical abnormalities were hypochloremia (51.2%), metabolic alkalosis (45.2%), hyperlactatemia (40.5%), hypokalemia (25%), and hyponatremia (20.5%). Nearly 75% of the dogs had pH values within the reference range of 7.36 to 7.47. No significant association was found between any biochemical abnormality and the site of the foreign body. Linear foreign bodies were significantly associated with lower sodium concentrations (possibly because of incomplete obstructions and continued water intake) and with longer surgery times (possibly because of multiple enterotomies).

The authors concluded that because of the wide variability in biochemical abnormalities, electrolyte concentrations and acid-base parameters should be measured in dogs with a suspected GI foreign body to optimize fluid therapy before surgery.

COMMENTARY

GI foreign bodies are frequently encountered in small-animal practice. This article focuses on the biochemical abnormalities seen in patients with GI foreign bodies and reminds clinicians of the need for preoperative evaluation and selection of the correct fluid therapy. While specific associations between the locations or types of foreign body and biochemical abnormalities (other than sodium) are difficult to make, the reduced morbidity and mortality of the patients in this study should be noted. This reduction is probably related to the early admission of patients and the exclusion of patients with complicated septic conditions. The short duration of vomiting and aggressive medical and surgical interventions are probably responsible for these results and should be noted by practitioners.

Boag AK, Coe RJ, Martinez TA, et al. Acid-base and electrolyte abnormalities in dogs with gastrointestinal foreign bodies. J Vet Intern Med 2005;19:816-821.

The information in "Research Updates" was provided by Veterinary Medicine Editorial Advisory Board member Joseph Harari, MS, DVM, DACVS, Veterinary Surgical Specialists, 21 E. Mission Ave., Spokane, WA 99202.

Joseph Harari, MS, DVM, DACVS