Use of Intraoperative Ultrasonography in Six Horses

Intraoperative ultrasonography was used in six horses to aid localization and removal of bone fragments (3 horses) and foreign bodies (3 horses). The ultrasound transducer was enclosed in a sterile sleeve containing sterile aqueous gel and the examination was performed after aseptic preparation of the surgical site. Using ultrasound guidance a needle was placed in contact with the bone fragment or foreign body and an incision was made along the path of the needle to expose and remove the object. This technique resulted in decreased operative time and minimal tissue dissection.     

Indications and Techniques for Blood Transfusion in Birds

There is growing medical care related to emergency presentations and procedures used to treat companion and wild birds. These critical care procedures (e.g., blood transfusion) can be life-saving. To maximize the beneficial effects of blood transfusions administered to avian patients, it is necessary to have an understanding of avian hematology and erythropoiesis, recognize clinical conditions in which one performs a blood transfusion, know the proper procedures and techniques, and rapidly identify possible adverse reactions.     

Standing Lateral Thoracotomy in Horses: Indications,Complications, and Outcomes

Objective: To describe the indications for, complications arising from, and outcome of horses that had standing lateral thoracotomy for pleural or pericardial disease. Study Design: Case series. Animals: Horses (n=16). Methods: Medical records (January 1990–December 2008) of sedated standing horses that had lateral thoracotomy were reviewed. Clinical and surgical findings, perioperative and short‐term complications were recorded. Long‐term (>6 months) outcome was determined through telephone conversations with owners and veterinarians. Results: Mean (±SD) horse age was 6.6±5.3 years (range, 1–15 years). Thoracotomy was most commonly for treatment of recurrent or chronic pleural infection (94%). Anaerobic bacteria were frequently isolated from pleural effusion associated with pleuropneumonia (63%). Right lateral intercostal thoracotomy was performed in 13 horses (82%); intercostal muscle myectomy in 5 horses; and rib resection in 1. Perioperative complications were hemipneumothorax (2 horses) and short‐term complications included cellulitis and abscessation of the thoracotomy site (6 horses). Fourteen (88%) horses survived to discharge and 46% of horses that survived returned to their previous level of athletic activity. Conclusions: Lateral thoracotomy is well tolerated by standing sedated horses with minimal perioperative and short‐term complications. Clinical Relevance: Standing lateral thoracotomy should be considered for the treatment of complicated pleuropneumonia in horses.     

Comparison of Three Drilling Techniques for Carpometacarpal Joint Arthrodesis in Horses

Objective: To evaluate 3 drilling techniques for arthrodesis of the equine carpometacarpal (CMC) joint. Study Design: Experimental study. Sample Population: Cadaveric equine forelimbs (n=15). Methods: Limbs were divided into 3 groups (5 limbs each) to evaluate 3 drilling techniques: (1) use of a 4.5 mm drill bit inserted into the joint through 4 entry points and moved in a fanning motion; (2) a 5.5 mm drill bit inserted through 2 entry points to create 3 nonfanned drill tracts (3 drill technique); and (3) a 4.5 mm drill bit used in a 3 drill technique. The CMC joint was disarticulated after drilling, and cartilage and subchondral bone damage evaluated visually and by gross and microradiographic examination using planimetry. Results: Technique 1 produced significantly more damage of the proximal surface, but significantly less to the subchondral bone of the distal surface. Technique 1 produced the most damage to both the articular cartilage and subchondral bone of the total CMC joint than either of the 3 drill tract techniques; however, the difference between techniques 1 and 2 was not significant. Damage from technique 3 was significantly less than that with techniques 1 or 2. Conclusions: Techniques 1 and 2 produced the most cartilage and subchondral bone damage with technique 2 changes more equally distributed between proximal and distal joint surfaces. Clinical Relevance: Technique 1 (fanning) and 2 (5.5 mm 3 drill tracts) may be preferable to achieve arthrodesis of the CMC joint. Morbidity and efficacy of these arthrodesis techniques need to be evaluated in vivo.     

The Use of Ultrasound to Assess the Thrombogenic Properties of Teflon and Polyurethane Catheters for Short-Term Use in Systemically Healthy Horses

The objective of this study was to establish an ultrasound scoring system to assess the degree of fibrin tag and clot formation associated with jugular catheters in horses. A second objective was to test the hypothesis that, in healthy horses undergoing short-term anesthesia, polyurethane (PU) catheters have a different ultrasound score compared with polytetrafluoroethylene (Teflon) catheters. Twenty-three systemically healthy horses requiring anesthesia were randomly assigned PU or Teflon catheters. The mean catheter dwell time was 5 hours. Ultrasound was used to examine the jugular vein before catheter placement, before catheter removal (mean, 4 hours 45 minutes), and approximately 24 hours after catheter insertion (mean, 24 hours 42 minutes). The repeatability of the ultrasound scoring system was assessed by producing a series of randomly ordered selected still images for independent evaluation by four radiologists on two separate occasions. The interobserver and intraobserver repeatability was determined using a weighted kappa statistic, with substantial intraobserver repeatability mean κ .77 (range, .59–.91) and moderate interobserver repeatability mean κ .53 (range, .33–.67). The proportion of positive bacteriologic cultures in the polyurethane (PU) and Teflon groups was compared using Fisher's exact test, with no significant difference (P > .99) between the two groups. The distribution of the scores from the PU and Teflon groups was compared using the Mann-Whitney test, with no evidence of a difference between groups at the time of catheter removal (P = .23) and 24 hours after catheter insertion (P = .20). Further studies with a larger sample of systemically healthy horses are required to substantiate this preliminary finding.     

A Modified Parainguinal Approach for Cryptorchidectomy in Horses An Evaluation in 107 Horses

A modified parainguinal approach was used to castrate 119 abdominal cryptorchid horses. The operative time ranged from 10 to 30 minutes. Follow-up information was obtained for 107 horses. Swelling, more severe than that expected in routine castrations, was reported in six horses. An incisional abscess had to be drained in one horse and one horse died of unexplained causes 3 days after the surgery.     

Comparison of 5 Surgical Techniques for Partial Liver Lobectomy in the Dog for Intraoperative Blood Loss and Surgical Time

Objective: To compare surgical time and intraoperative blood loss for 5 partial liver lobectomy techniques in the dog. Study Design: Experimental in vivo study. Animals: Dogs (n=10). Methods: Five surgical techniques (SurgiTie^?; LigaSure^?; Ultracision^® Harmonic Scalpel [UAS]; Suction+Clip; Suction+thoracoabdominal stapler [TA]) for partial liver lobectomy in dogs were evaluated and compared for total surgical time and intraoperative blood loss. Body weight, activated clotting time (ACT), heart rate, and intraoperative blood pressure (BP) were recorded. Blood loss was determined by adding the weight of the blood soaked sponges during surgery (1 g=1 mL) to the amount of suctioned blood (mL). Surgical time (in seconds) was determined from the start of the lobectomy until cessation of bleeding from the stump. Mean surgical time and mean blood loss for each technique were compared using a Tukey's multiple comparison test. Results: No significant differences were found between dogs for weight, ACT, heart rate, and intraoperative BP. No complications were seen with the SurgiTie^? technique in 9 of 10 cases. There was no significant difference in surgical time between techniques however there was a significant difference for blood loss; the Suction+Clip method had significantly more blood loss than the other techniques. Conclusions: Skeletonization of the lobar vessels before individually clipping them (Suction+Clip) resulted in a higher blood loss than using Suction+TA, UAS, SurgiTie^? or the LigaSure^? device. The SurgiTie^? appears to be an acceptable method for partial liver lobectomy. Clinical Relevance: Although skeletonization and individually clipping the vessels had the highest blood loss, it still was <7.5% of total blood volume. All 5 techniques should be safe for clinical use in small to medium sized dogs up to 26 kg.     

Grass Varieties for Horses

Many horse owners are concerned about sugar and fructosan levels in pastures and hay. While levels of these components have not changed in forages over the last century, the needs of horses have. Significant range in nonstructural carbohydrate contents of all grass species would allow for selection of varieties with lowered levels of these components. However, the grass seed industry must perceive a market for these types of grass before they would invest in the development of varieties and seed production and marketing of such types. Levels of these components currently vary with species, management, and the environment in which the plant is/has grown. Horse owners should be aware of these differences and use them to the benefit of their horses. Significantly lower levels of sugars and fructosans can be obtained by selecting grass species for low water soluble carbohydrate, then pastures can be managed or hay harvested with management practices favoring lowered nonfibrous carbohydrates. Forage can be analyzed for fructan or sugar, starch, and fructan can be estimated from nonfibrous carbohydrate analysis which is commonly determined in forage analysis.     

Use of Ultrasound In Horses for Diagnosis of Left Dorsal Displacement of the Large Colon and Monitoring its Nonsurgical Correction

During a 28 month period, 82 horses with clinical signs of abdominal pain were examined for left dorsal displacement of the large colon (LDDLC) using percutaneous ultrasound. Left dorsal displacement of the large colon was diagnosed when a gas echo dorsal to the spleen obliterated the dorsal splenic border, or when the colon was observed lateral to the spleen. In 42 horses, ultrasound confirmed a diagnosis of LDDLC and 40 horses had no evidence of LDDLC. There were five false negative results and no false positives. In four horses with LDDLC, the colon was displaced between the spleen and body wall; three of these colic episodes resolved with medical therapy and the fourth required a celiotomy to relieve a sand impaction. The remaining 38 horses had a renosplenic entrapment; surgical correction was elected in 4 horses, 21 horses were corrected by a nonsurgical rolling procedure, 12 were corrected at surgery after an unsuccessful rolling attempt, and one was corrected by rolling but required surgery later because of an additional lesion. Percutaneous abdominal ultrasound was a valuable aid in the diagnosis of LDDLC and in confirming correction of the displacement after a nonsurgical rolling procedure.     

Detomidine-Propofol Anesthesia for Abdominal Surgery in Horses

OBJECTIVE: To evaluate propofol for induction and maintenance of anesthesia, after detomidine premedication, in horses undergoing abdominal surgery for creation of an experimental intestinal adhesion model. STUDY DESIGN: Prospective study. ANIMALS: Twelve horses (424 +/- 81 kg) from 1 to 20 years of age (5 females, 7 males). METHODS: Horses were premedicated with detomidine (0.015 mg/kg i.v.) 20 to 25 minutes before induction, and a propofol bolus (2 mg/kg i.v.) was administered for induction. Propofol infusion (0.2 mg/kg/min i.v.) was used to maintain anesthesia. The infusion rate was adjusted to maintain an acceptable anesthetic plane as determined by muscle relaxation, occular signs, response to surgery, and cardiopulmonary responses. Oxygen (15 L/min) was insufflated through an endotracheal tube as necessary to maintain the SpO2 greater than 90%. Systolic (SAP), mean (MAP), and diastolic (DAP) arterial pressures, heart rate (HR), electrocardiogram (ECG), respiratory rate (RR), SpO2 (via pulse oximetry), and nasal temperature were recorded at 15 minute intervals, before premedication and after induction of anesthesia. Arterial blood gas samples were collected at the same times. Objective data are reported as mean (+/-SD); subjective data are reported as medians (range). RESULTS: Propofol (2.0 mg/kg i.v.) induced anesthesia (mean bolus time, 85 sec) within 24 sec (+/-22 sec) after the bolus was completed. Induction was good in 10 horses; 2 horses showed signs of excitement and these two inductions were not smooth. Propofol infusion (0.18 mg/kg/min +/- 0.04) was used to maintain anesthesia for 61 +/- 19 minutes with the horses in dorsal recumbency. Mean SAP, DAP, and MAP increased significantly over time from 131 to 148, 89 to 101, and 105 to 121 mm Hg, respectively. Mean HR varied over time from 43 to 45 beats/min, whereas mean RR increased significantly over anesthesia time from 4 to 6 breaths/min. Mean arterial pH decreased from a baseline of 7.41 +/- 0.07 to 7.30 +/- 0.05 at 15 minutes of anesthesia, then increased towards baseline values. Mean PaCO2 values increased during anesthesia, ranging from 47 to 61 mm Hg whereas PaO2 values decreased from baseline (97 +/- 20 mm Hg), ranging from 42 to 57 mm Hg. Muscle relaxation was good and no horses moved during surgery: Recovery was good in 9 horses and acceptable in 3; mean recovery time was 67 +/- 29 minutes with 2.4 +/- 2.4 attempts necessary for the horses to stand. CONCLUSIONS: Detomidine-propofol anesthesia in horses in dorsal recumbency was associated with little cardiovascular depression, but hypoxemia and respiratory depression occurred and some excitement was seen on induction. CLINICAL RELEVANCE: Detomidine-propofol anesthesia is not recommended for surgical procedures in horses if dorsal recumbency is necessary and supplemental oxygen is not available (eg, field anesthesia).