Effects of 7.2% hypertonic saline solution on cardiovascular parameters and endogenous arginine vasopressin secretion in euvolemic isoflurane-anesthetized horses.

OBJECTIVE: To compare the effects of 7.2% hypertonic and 0.9% isotonic saline (sodium chloride) solutions on cardiovascular parameters and plasma arginine vasopressin (AVP) concentrations in healthy, isoflurane-anesthetized horses. ANIMALS: 8 healthy horses. PROCEDURES: In a prospective, randomized, crossover study, horses were anesthetized with isoflurane twice with a 14-day washout period between anesthetic episodes. While anesthetized, horses received a bolus (4 mL/kg) of 7.2% hypertonic saline solution (HS) or 0.9% isotonic saline solution (IS). Heart rate; systolic, mean, and diastolic arterial blood pressures; and central venous and pulmonary artery pressures were measured every 5 minutes; cardiac output was measured by means of thermodilution every 15 minutes. Systemic vascular resistance (SVR) was calculated. Blood samples were collected before and during anesthesia, and plasma AVP concentrations were determined with a validated ELISA. Data were analyzed with repeated-measures ANOVA and Pearson correlations. RESULTS: HS caused an increase in systolic (P = .003) and mean (P = .023) arterial blood pressures that lasted for 30 minutes. The SVR was increased (P < .001) for 45 minutes with HS compared with the SVR after IS administration. Mean plasma AVP concentration increased (P = .03) 15 minutes after HS administration, with the increase lasting 90 minutes. CLINICAL RELEVANCE: A bolus of HS resulted in a clinically relevant increase in blood pressure in healthy, isoflurane-anesthetized horses. This effect was attributed to volume recruitment and an increase in SVR. Administration of HS offers an option for improving arterial blood pressure in anesthetized horses.

Comparison of the zip skin closure system with conventional suture for skin closure of ventral midline incisions in horses.

OBJECTIVE: To compare the application and healing of the zip skin closure system (ZSCS) with sutured closure by use of a split-scar model of ventral midline incisions in horses in a prospective, randomized experimental study. ANIMALS: 8 adult horses. PROCEDURES: All horses underwent an exploratory ventral midline celiotomy with a standardized 30-cm skin incision. Each horse was randomized to have either the cranial 15 cm closed with suture and caudal 15 cm with the ZSCS or vice versa (split-scar model). Skin closure time was recorded and compared. Photography and skin biopsies were taken preoperatively and 14 days postoperatively. Cosmetic appearance was assessed by use of a proposed equine celiotomy incision score. Healing at 14 days was assessed by histopathology. RESULTS: Skin closure times were faster with the ZSCS compared to sutured incisions. At 14 days postoperatively, the cosmetic appearance (equine celiotomy incision scores) for ZSCS incisions were better than sutured closure and histologic healing scores were not different between methods of closure. Subcuticular sutures were associated with deep dermal inflammation and necrosis independent of epidermal closure methods. CLINICAL RELEVANCE: While limitations to the utility of the ZSCS are recognized, the potential benefits of expedient closure, good cosmetic outcome, and satisfactory healing make this method viable for closure of linear wounds or incisions in horses.