Objective: To review and discuss the use of hydroxyethyl starches (HES) in equine veterinary medicine, and to provide recommendations for its use.
Data sources: Veterinary and human peer-reviewed medical literature including scientific reviews, meta-analyses, and original research articles.
Human data synthesis: Increasing evidences on adverse effects after HES use and decreasing support for beneficial effects with regards to volume expansion and colloid osmotic pressure (COP) support in critically ill subjects have led to a recent guideline to limit the use of HES in critically ill people.
Equine veterinary data synthesis: The rationale for HES use in horses is mainly extrapolated from human medicine, and very limited studies in horses are available. There is limited evidence suggesting a superiority of volume expansion effects of HES over crystalloids. The potential for HES to increase and maintain COP is well supported, but there is no evidence that maintaining or increasing plasma COP influences outcome, tissue edema formation, or rates of complications that potentially relate to edema formation. HES induce dose-dependent changes in coagulopathic parameters, but there is no evidence that HES causes clinical coagulopathies. Insufficient data are available on other adverse effects such as acute kidney injury, or mortality in horses. The use of HES should be restricted in septic patients, but may still have some use in cases of hemorrhagic shock resuscitation, hypoalbuminemia, or perioperative fluid replacement.
Conclusion: The evidence supporting the use of HES in horses is weak due to lack of species-specific investigations. Acknowledging species differences, the use of HES should be judicious, yet with some recognition of its benefits in particular cases. More research is necessary to improve knowledge on use of HES in horses and to establish better future recommendations.
Objective: To describe a case of massive transfusion using unwashed, non-anticoagulated, nonsterile autologous blood in a dog with catastrophic hemorrhage from a peripheral vessel during orthopedic surgery. A damage control surgical strategy was also employed.
Case summary: A 6-year-old, 48 kg neutered male Labrador Retriever experienced massive hemorrhage after transection of a large blood vessel while undergoing femoral head and neck osteotomy. Blood was collected from clean, but not sterile, suction canisters and clots were skimmed off. The blood was then transfused back to the dog using a standard in-line blood filter. Approximately 58% of the dog's blood volume was autotransfused in less than 2 hours, thereby meeting the criteria for massive transfusion. Surgery was aborted after hemostasis was achieved by ligation of the vessel and packing of the surgical site. Two units of fresh frozen plasma were administered postoperatively due to the development of a coagulopathy. Hemoglobinuria developed but resolved within 18 hours. Three days later, completion of the surgical procedure was performed without incident. The dog was discharged 4 days after the initial surgery. Marked swelling of the affected limb developed, but resolved after the sixth day. No other significant complications developed.
New or unique information provided: In this case report, the authors describe the successful management of catastrophic hemorrhage with autotransfusion performed in the absence of sterile collection, cell washing, or anticoagulation. Although not ideal, autotransfusion under these conditions can be lifesaving in situations of massive hemorrhage. This case also highlighted the employment of a damage control surgical strategy.
Objective: To describe 2 cases of organophosphate intoxication through a previously unreported method of exposure.
Case series: A 2-year-old intact male Australian Cattle Dog (case 1) presented with progressive muscarinic and nicotinic clinical signs, and a 3-year-old neutered male mixed breed dog (case 2) presented after known ingestion of cattle ear tags. The dog in case 1 was discovered to have ingested cattle ear tags after abdominal radiographs. Organophosphate testing of gastric contents confirmed diazinon toxicosis. The dog in case 2 was found to be eating ear tags by the owner. The tags in case 2 contained diazinon and coumaphos. The dog in case 1 was treated with gastric lavage, gastroprotectants, prokinetics, antiemetics, pralidoxime chloride, and atropine. The dog in case 2 was treated with pralidoxime chloride. Both patients received standard supportive and nursing care and recovered completely with no further concerns.
New or unique information provided: This is a novel exposure to organophosphates that has not been reported in small animals. In dogs with relevant clinical signs and potential environmental exposure, cattle ear tag ingestion is an important differential diagnosis to consider.
Objective: To characterize a population of cats with pelvic trauma and evaluate factors influencing transfusion requirement and outcome.
Design: Retrospective case series (2009-2014).
Setting: University teaching hospital.
Animals: One hundred twelve client-owned cats with pelvic trauma.
Interventions: None.
Measurements and main results: Twenty-one (18.8%) cats received a transfusion. Most cats required only 1 fresh whole blood transfusion (85.8%). Packed cell volume at admission was significantly lower in cats that required transfusion but was not associated with hospitalization time or survival to discharge. Increasing Animal Trauma Triage (ATT) score at admission was significantly associated with transfusion requirement (P = 0.0001) and nonsurvival to discharge (P = 0.03). Number of pelvic fractures was not associated with transfusion requirement but cats with sacroiliac luxations and pubic fractures were more likely to require a transfusion (P = 0.0015 and P = 0.0026, respectively). However, fracture type was not associated with survival to discharge. Most cats (86%) required a surgical procedure and half of transfusions were administered preoperatively. No surgical comorbidities were associated with transfusion requirement or survival. Transfusion requirement was associated with longer length of hospitalization but not survival to discharge.
Conclusions: Transfusion requirement in this population of cats with pelvic fractures was fairly high. Transfusion requirement was associated with lower packed cell volume, higher ATT score at admission, longer length of hospitalization, and certain types of pelvic fractures. Transfusion requirement was not associated with surgical comorbidities, surgical intervention, or survival to discharge. Lower ATT score at admission was associated with survival to discharge.
Objective: To investigate whether percentage changes in pulse wave transit time (PWTT%Δ) induced by mini-fluid challenges predict fluid responsiveness in mechanically ventilated anesthetized dogs.
Design: Prospective experimental trial.
Setting: University teaching hospital.
Animals: Twelve Harrier hounds.
Intervention: Each dog was anesthetized with propofol and isoflurane after premedication with acepromazine, mechanically ventilated, and had a fluid challenge. This was repeated 4 weeks later. The fluid challenge, 10 mL/kg of colloid administration over 13 minutes, consisted of 3 intermittent mini-fluid challenges (1 mL/kg of each over a minute) with a minute interval, and the remaining colloid administration (7 mL/kg) over 7 minutes.
Measurements and main results: Percentage change in velocity time integral of pulmonary arterial flow by echocardiography was calculated as an indication of change in stroke volume. Fluid responsiveness was defined as percentage change in velocity time integral ≥ 15% after 10 mL/kg colloid. Dogs responded on 14 fluid challenges and did not on 10. After 1, 2, 3, and 10 mL/kg of fluid challenge, PWTT%Δ1, 2, 3, 10 were measured. Receiver operator characteristic (ROC) curves were generated and areas under ROC curve were calculated for PWTT%Δ1, 2, 3 . A gray zone approach was used to identify the clinically inconclusive range. The area under the ROC curve for PWTT%Δ3 was 0.91 (P = 0.001). Cutoff value for PWTT%Δ3 was -2.5% (sensitivity: 86%, specificity: 90%). The gray zone for PWTT%Δ3 was identified as between -2.9% to -1.9% for which fluid responsiveness could not be predicted reliably in 6 out of 24 fluid challenges.
Conclusions: In mechanically ventilated anesthetized dogs given a mini-fluid challenge of 3 mL/kg of colloid, PWTT%Δ could predict fluid responsiveness although the gray zone should be considered.
Objective: To compare intravenous and intraosseous blood aspirates using point-of-care diagnostic equipment available in veterinary hospitals.
Design: Prospective study.
Setting: Private referral hospital.
Animals: Dogs undergoing a tibial plateau leveling osteotomy or extracapsular anterior cruciate ligament stabilization procedure were enrolled.
Methods: Under general anesthesia, simultaneous 0.5 mL intravenous and intraosseous blood samples were collected from the jugular vein and proximal tibia, respectively. Samples were evaluated in duplicate within 10 minutes of collection and averaged for each of the following parameters: blood urea nitrogen (BUN), glucose, packed cell volume, total plasma protein (TPP), plasma lactate, sodium, potassium, chloride, urea, glucose, pH, anion gap, pO2, and pCO2 . Normalcy was tested with Kolmogorov-Smirnov test. A Student's t-test and Bland-Altman plot were used to compare intravenous and intraosseous samples.
Results: Twelve dogs were recruited into the study. There were statistically significant differences between intravenous and intraosseous samples for sodium (P = 0.0216), chloride (P = 0.0225), BUN (P = 0.014), and potassium (P < 0.0001), respectively. No significant differences were detected for the other parameters evaluated.
Discussion: The intraosseous space provides an easily accessible, noncollapsible alternative for assessing blood parameters. Omitting potassium, the statistically significant differences noted between sites was not felt to be clinically significant. Although statistically insignificant, the large difference in hematocrit values indicates that the samples should not be used interchangeably.
Conclusion: Intraosseous aspirates, excluding potassium and hematocrit, appear to be a reliable alternative for assessing most point-of-care analytes in healthy dogs, although a larger sample size should be investigated. The application of these data in shock patients is unknown.
Objective: To describe the use of pericardial catheters in dogs with pericardial effusion (PE), and detail any associated adverse events.
Design: Retrospective study.
Setting: University teaching hospital.
Animals: Eighteen client-owned dogs that had pericardial catheters placed for pericardial fluid drainage between May 2007 and January 2015.
Interventions: None.
Measurements and main results: All pericardial catheters were placed within 5 hours of presentation, usually within 1 hour (median 72.5 min, range 45-300 min). Ten of 18 cases were sedated with butorphanol, and 4 with additional midazolam. Four had pericardial catheters positioned for single drainage only and were immediately removed. The other 14 pericardial catheters remained in situ for a median of 18 hours (range 2-88 h). Ten of the remaining 14 cases were redrained after pericardial catheter placement. The main adverse events reported were new arrhythmias in 6/18 cases, with 4 of these 6 patients being administered anti-arrhythmic therapy. No infectious or functional complications were reported. Ten patients were discharged, 1 died and 7 were euthanized.
Conclusions: Thoracic drainage catheters inserted into the pericardial space via a modified-Seldinger technique can be positioned in dogs to aid management of PEs. The main associated adverse event is arrhythmia. Minimal sedation is required for placement, and dogs tend not to require postprocedural analgesia. Catheters can remain in situ for repeated drainage, potentially decreasing staffing time requirement and repeat sedation. Their use is associated with a rate of arrhythmia requiring treatment of 22%, compared to that of needle pericardiocentesis alone at 13%. They are easy to position using equipment available in many facilities.