Retrospective evaluation of the prognostic utility of quick sequential organ failure assessment scores in dogs with surgically treated sepsis (2011-2018): 204 cases.

OBJECTIVE: To assess the prognostic utility of admission quick Sequential Organ Failure Assessment (qSOFA) scores for in-hospital mortality in a population of dogs with surgically treated sepsis. DESIGN: Retrospective cohort study of dogs from January 2011 to January 2018. SETTING: University teaching hospital. ANIMALS: One thousand three hundred nine cases were identified with a clinical diagnosis of sepsis requiring surgical source control. Two hundred and four dogs with surgically treated sepsis met inclusion criteria, defined as: meeting 2 or more systemic inflammatory response syndrome (SIRS) criteria with a documented source of infection. One hundred and forty-three cases of septic peritonitis, 26 cases of septic soft tissue infection, 20 cases of pyometra, and 15 cases of pyothorax were evaluated. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Overall in-hospital mortality was 63 of 204 (30.9%). Patients with a qSOFA ≥ 2 were more likely to die or be euthanized (odds ratio [OR] 7.1, 95% confidence interval [CI] 2.9-16.4; P < 0.0001). Survivor and nonsurvivor qSOFA scores were significantly different in all categories. Dogs with septic peritonitis and a qSOFA ≥ 2 had an increased risk of postoperative complications (OR 3.9; 95% CI 1.3-11.1; P = 0.02). qSOFA scores were correlated with length of hospitalization in survivors of all-cause surgical sepsis (r = 0.28, P = 0.0007), septic peritonitis (r = 0.33, P = 0.001), and septic soft tissue infection (r = 0.59, P = 0.004). CONCLUSIONS: This was the first study to retrospectively evaluate the prognostic utility of qSOFA scores in dogs surgically treated for sepsis. Dogs diagnosed with septic peritonitis and other causes of surgically treated sepsis with a qSOFA ≥ 2 may have a higher risk of in-hospital mortality, although future prospective studies are necessary.

The use of impedance aggregometry to evaluate platelet function after the administration of DDAVP in healthy dogs treated with aspirin or clopidogrel.

OBJECTIVE: To evaluate the effect of 1-Desamino-8-d-arginine vasopressin (DDAVP; desmopressin acetate) on platelet aggregation in healthy dogs receiving aspirin or clopidogrel. ANIMALS: 7 healthy staff-owned dogs. PROCEDURES: In this randomized double-blinded crossover study, impedance aggregometry was performed on samples of lithium-heparinized whole blood samples from dogs before (T0) treatment with aspirin (1 mg/kg, PO, q 24 h for 4 days; ASP group) or clopidogrel (1 mg/kg, PO, q 24 h for 4 days; CLP group) and then before (T1) and after (T2) treatment with DDAVP (0.3 µg/kg, IV, once). There was a 14-day washout period before the crossover component. Aggregometry was performed with 4 different assays, each of which involved a different agonist reagent to stimulate platelet function: ADP, thrombin receptor activating peptide-6, arachidonic acid, or collagen type 1. RESULTS: Median results for platelet aggregometry with agonist reagents ADP, arachidonic acid, or thrombin receptor activating peptide-6 significantly decreased between T0 and T1 for the CLP group; however, no meaningful difference in platelet aggregation was detected in the ASP group. Results for platelet aggregometry did not differ substantially between T1 and T2 regardless of treatment group or assay. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggested that administration of DDAVP may have no effect on platelet aggregation (measured with platelet aggregometry) in healthy dogs treated with clopidogrel. Because no inhibition of platelet aggregation was detected for dogs in the ASP group, no conclusion could be made regarding the effects of DDAVP administered to dogs treated with aspirin.

Metronidazole treatment of acute diarrhea in dogs: A randomized double blinded placebo-controlled clinical trial.

BACKGROUND: Metronidazole is commonly administered to dogs with acute diarrhea, but there is limited evidence to support this practice. OBJECTIVE: To investigate the effects of metronidazole administration on dogs with acute nonspecific diarrhea. ANIMALS: Thirty-one dogs, including 14 test population dogs and 17 controls. METHODS: Randomized controlled clinical trial. Dogs with acute diarrhea in which causation was not determined by routine fecal diagnostic testing were randomly assigned to metronidazole treatment (10-15 mg/kg PO q12h for 7 days) or placebo. Fecal cultures and characterization of Clostridium perfringens isolates also were performed. Owners maintained medication and fecal scoring logs, and fecal diagnostic tests were repeated on day 7. RESULTS: The mean ± SD time to resolution of diarrhea for test population dogs (2.1 ± 1.6 days) was less than that for controls (3.6 ± 2.1 days, P = .04). Potential relationships of C. perfringens with acute diarrhea pathogenesis were not investigated, but only 3 of 13 (23.1%) test population dogs had persistent C. perfringens carriage at day 7, which was less than the 11 of 14 (78.6%) controls with persistent growth (P = .007). CONCLUSIONS AND CLINICAL IMPORTANCE: Our results suggest that metronidazole treatment can shorten duration of diarrhea and decrease fecal culture detection of C. perfringens in some dogs with acute nonspecific diarrhea. Additional studies are needed to assess the benefits and risks of routine use of metronidazole for this purpose because most dogs achieve resolution of diarrhea within several days regardless of treatment.

Retrospective evaluation of the clinical course and outcome following grape or raisin ingestion in dogs (2005-2014): 139 cases.

OBJECTIVE: To describe the prevalence of acute kidney injury (AKI), clinical course, decontamination procedures, and outcome in dogs following grape or raisin ingestion. DESIGN: Retrospective case series from 2005 to 2014. SETTING: Three university veterinary teaching hospitals. ANIMALS: One hundred thirty-nine client-owned dogs with known grape or raisin ingestion. MEASUREMENTS AND MAIN RESULTS: Among dogs with biochemical data, the prevalence of AKI was 6.7% (8/120). The prevalence of AKI in the early presentation (3/67) and late (5/53) presentation groups were 4.5% and 9%, respectively. The prevalence of AKI was not significantly different between groups (P = 0.27). Four dogs (3.3%) were azotemic at presentation and 4 dogs (3.3%) had increases in creatinine of ≥26.5 µmol/L (0.3 mg/dL) at recheck (3 from the early and 1 from the late group). Vomiting was the most common clinical sign (18/139). One hundred twenty-two dogs (88%) underwent gastrointestinal decontamination and significantly more dogs in the early group were decontaminated (P < 0.0001). Two dogs received continuous renal replacement therapy. One hundred thirty-eight dogs survived and 1 died. CONCLUSIONS: The prevalence of AKI and mortality was low in dogs with confirmed grape or raisin ingestion. Due to the retrospective nature of the study, conclusions about the utility of gastrointestinal decontamination and other therapies cannot be made.

Clinical features of precursor-targeted immune-mediated anemia in dogs: 66 cases (2004-2013).

OBJECTIVE: To characterize the clinical features of dogs with precursor-targeted immune-mediated anemia (PIMA). ANIMALS: 66 dogs with PIMA. PROCEDURES: Electronic record databases of a teaching hospital were searched to identify dogs with a diagnosis of nonregenerative anemia between 2004 and 2013. Inclusion criteria included persistent nonregenerative anemia (Hct ≤ 30% and reticulocyte count < 76,000 reticulocytes/µL), cytologic findings supportive of ineffective bone marrow erythropoiesis, and absence of underlying disease. Information regarding clinical signs, clinicopathologic findings, treatment, and outcome was extracted from records of eligible dogs. A regenerative response was defined as a reticulocyte count > 76,000 reticulocytes/µL or sustained increase in Hct of > 5%. Remission was defined as a stable Hct ≥ 35%. RESULTS: The median Hct was 13%, and reticulocyte count was 17,900 reticulocytes/µL. Rubriphagocytosis was identified in bone marrow aspirate samples from 61 of 66 dogs. Collagen myelofibrosis was detected in bone marrow biopsy specimens obtained from 31 of 63 dogs. Immune-mediated targeting of mature erythrocytes was uncommon. All dogs received immunosuppressive therapy. Fifty-five dogs developed a regenerative response at a median of 29 days, and 40 of those dogs went into remission at a median of 59 days after PIMA diagnosis. Thromboembolic events were confirmed for 9 dogs and were associated with a decreased survival time. Median survival time was 913 days for all dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that most dogs with PIMA responded to prolonged immunosuppressive therapy. Studies to determine optimal immunosuppressive and thromboprophylactic protocols for dogs with PIMA are warranted.

Clinical experience utilizing a novel fluoroscopic technique for wire-guided esophagojejunal tube placement in the dog and cat: Twenty cases (2010-2013).

OBJECTIVE: To describe the clinical use of a novel, minimally invasive technique for fluoroscopic wire-guided esophagojejunal tube (FEJT) placement in dogs and cats. DESIGN: Retrospective study (February 2010-September 2013). SETTING: University veterinary teaching hospital. ANIMALS: Eighteen dogs and 2 cats with intolerance of, or contraindications to, gastric feeding that underwent attempted FEJT placement. INTERVENTIONS: All patients underwent attempted FEJT placement using a novel fluoroscopic wire-guided technique. MEASUREMENTS AND MAIN RESULTS: Patient data were collected including information about the FEJT placement and utilization of the tube postplacement. The primary diagnosis in dogs undergoing FEJT placement was pancreatitis in 61% of cases. The ability to achieve postpyloric access with the technique was 95% (19/20). Mean duration of the procedure in dogs where FEJT placement was successful was 63.8 minutes (SD, 28.6; min-max, 30-120 min). Mean fluoroscopy time was 19.4 minutes (SD, 11.5; min-max, 5.2-42.1-min). Esophagostomy site infection was a complication of FEJT placement in 2 dogs. The mean duration the FEJT remained in place in dogs was 3.8 days (SD, 2.2; min-max, 1-7 days), and mean duration of feeding was 3.6 days (SD, 2.2; min-max, 1-7 days). Vomiting was noted in 89% of patients prior to FEJT placement and was significantly reduced to only 24% of patients postplacement (P = 0.0001). CONCLUSIONS: FEJT placement is a viable technique for providing postpyloric nutrition in dogs and cats intolerant of, or with contraindications to, gastric feeding.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 4-Refining and monitoring antithrombotic therapies.

OBJECTIVES: To systematically review the evidence for therapeutic monitoring of antithrombotic drugs in small animals, develop guidelines regarding antithrombotic monitoring, and identify knowledge gaps in the field. DESIGN: First, a standardized, systematic literature review was conducted to address predefined PICO (Population/Patient, Intervention, Control, Outcome) questions, with categorization of relevant articles according to level of evidence and quality. Preliminary guidelines were developed by PICO worksheet authors and the domain chair. Thereafter, a Delphi-style survey was used to develop consensus on guidelines regarding therapeutic monitoring of antithrombotics in dogs and cats. SETTING: Academic and referral veterinary medical centers. RESULTS: PICO questions regarding the utility of therapeutic monitoring were developed for 6 different antithrombotic drugs or drug classes, including aspirin, clopidogrel, warfarin, unfractionated heparin, the low molecular weight heparins, and rivaroxaban, The majority of the literature pertaining to therapeutic monitoring of antithrombotic drugs was either performed in experimental animal models of disease or involved studies of drug pharmacokinetics and pharmacodynamics in healthy laboratory animals. There was a paucity of high level of evidence studies directly addressing the PICO questions, which limited the strength of recommendations that could be provided. The final guidelines recommend that therapeutic monitoring should be performed when using warfarin or unfractionated heparin in dogs and cats at risk of thrombosis. There is insufficient evidence to make strong recommendations for therapeutic monitoring of aspirin or low molecular weight heparin in dogs and cats at this time. CONCLUSIONS: As in other CURATIVE domains, significant knowledge gaps were highlighted, indicating the need for substantial additional research in this field. Ongoing investigation of the role of therapeutic monitoring of antithrombotic therapies will undoubtedly facilitate improved outcomes for dogs and cats at risk of thrombosis.

Influence of immune-mediated hemolytic anemia on flow velocities in the portal vein and caudal vena cava measured by use of pulsed-wave Doppler ultrasonography in dogs.

OBJECTIVE To compare blood flow velocities of the portal vein (PV) and caudal vena cava (CVC) measured by use of pulsed-wave Doppler ultrasonography in clinically normal dogs and dogs with primary immune-mediated hemolytic anemia (IMHA). ANIMALS 11 client-owned dogs admitted to a veterinary teaching hospital for management of primary IMHA and 21 staff- or student-owned clinically normal dogs. PROCEDURES Flow velocities in the PV and CVC at the porta hepatis were evaluated in conscious unsedated dogs with concurrent ECG monitoring; evaluations were performed before dogs with IMHA received heparin or blood transfusions. Three measurements of peak velocity at end expiration were obtained for each vessel, and the mean was calculated. Results were compared between IMHA and control groups. RESULTS Mean ± SD blood flow velocity in the CVC differed between control (63.0 ± 18.6 cm/s) and IMHA (104 ± 36.9 cm/s) groups. Variance in dogs with IMHA was significantly greater than that for the clinically normal dogs. No significant difference in blood flow velocity in the PV was detected between IMHA and control dogs. CONCLUSIONS AND CLINICAL RELEVANCE Higher blood flow velocities were detected by use of pulsed-wave Doppler ultrasonography in the CVC of dogs with naturally occurring IMHA and may be used to predict anemia in patients suspected of having IMHA.

A retrospective evaluation of contrast-induced kidney injury in dogs (2006-2012).

OBJECTIVE: To evaluate a population of dogs for evidence of contrast-induced nephropathy (CIN). DESIGN: A retrospective case review between 2006 and 2012. SETTING: A university teaching hospital. ANIMALS: A total of 1,217 client-owned dogs that were administered intravenous iodinated contrast agents were reviewed for evidence of CIN. Inclusion required a measured serum creatinine within 1 week prior as well as within 1 week following administration of contrast. Eighty-six dogs with 92 contrast administrations qualified for inclusion. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: CIN was defined as an increase in >44.2 µmol/L (0.5 mg/dL) from baseline creatinine concentration within 1 week following administration of an intravenous iodinated contrast agent. A total of 7.6% of contrast administrations (7/92) fulfilled the definition of CIN. The creatinine postcontrast administration as well as the change in creatinine concentration was significantly higher in the CIN group than in the non-CIN group (median postcreatinine 150 µmol/L [1.7 mg/dL] versus 70.7 µmol/L [0.8 mg/dL], median change in creatinine 53 µmol/L [0.6 mg/dL] versus 0 µmol/L). Patient signalment, initial creatinine, number of total contrast administrations, dose of contrast received, duration of anesthesia, IV fluid administration, administration of nephrotoxic agents, and use or vasopressor therapy were not significantly different between groups. CONCLUSIONS: The temporal association between contrast administration and renal injury in these cases highlights the potential for CIN in dogs. Due to the retrospective nature of this study, a causal association between contrast administration and renal injury cannot be determined. A prospective study is needed to further evaluate CIN in dogs.

Retrospective evaluation of intravenous premixed amiodarone use and adverse effects in dogs (17 cases: 2011-2014).

OBJECTIVE: The goal of this study was to evaluate the number and frequency of adverse effects in a population of clinical canine patients receiving Nexterone. ANIMALS: Seventeen canine patients receiving Nexterone (five of which were treated during cardiopulmonary arrest). METHODS: An electronic records search for canine patients receiving intravenous Nexterone at the Michigan State University Veterinary Teaching Hospital was performed and retrospectively evaluated for patient demographic information, pre- and post-treatment values for heart rate, blood pressure and rhythm diagnosis, as well as any documented adverse effects (hypotension, anaphylaxis, vomiting, phlebitis, and death). Data including the underlying cardiac or systemic disease, concurrent medications, as well as the final clinical diagnosis and treatment outcome were also recorded. RESULTS: No adverse effects were noted in this population of clinical canine patients receiving Nexterone. The median pre-treatment heart rate and blood pressure values were 160 bpm (range 120-300 bpm) and 105 mmHg (range 60-170 mmHg), respectively. After treatment, the median heart rate was significantly lower (120 bpm; range 68-172 bpm). The median blood pressure similar to the pre-treatment blood pressure (115 mmHg; range 100-150 mmHg). CONCLUSION: In this study of 17 dogs receiving the premixed formulation of injectable Nexterone, no dogs were found to have acute adverse side effects. Nexterone appears to be a safe drug choice for in-hospital treatment of canine arrhythmias. Further studies are needed to assess the efficacy and long-term effects of this medication and the ideal dosing protocol for various arrhythmias.

Retrospective evaluation of concurrent intra-abdominal injuries in dogs with traumatic pelvic fractures: 83 cases (2008-2013).

OBJECTIVE: To report the occurrence of intra-abdominal injury (IA) in dogs with pelvic fractures due to blunt trauma, to evaluate for association between characterization of pelvic fractures and the presence of IA, and to evaluate for association between IA and other specific clinical conditions. DESIGN: Retrospective case series (2008-2013). SETTING: University teaching hospital. ANIMALS: Eighty-three client-owned dogs with pelvic fractures due to blunt trauma. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pelvic injuries included pubic fractures (90.4%), ischial fractures (80.7%), sacroiliac luxations (57.8%), iliac fractures (43.4%), acetabular fractures (30.1%), and sacral fractures (13.3%). Thirty-one dogs (37%) had IA, which included hemoabdomen (27 dogs), uroabdomen (3), and septic abdomen (3); 2 dogs had 2 types of IA. Dogs with sacral fractures were significantly more likely to have IA than dogs without sacral fractures (P = 0.0162). Characterization of pelvic fractures included the direction of compression, presence of a weight-bearing bone fracture, and degree of pelvic narrowing, none of which had an association with IA (P > 0.05). Dogs were more likely to have IA if they had cardiac dysrhythmia (P = 0.0002) or hematuria (P = 0.0001), and were more likely to have a hemoabdomen if they had cardiac dysrhythmia (P = 0.0005). Dogs with hematochezia were more likely to have a septic abdomen (P = 0.0123). Dogs were more likely to receive a transfusion if they had AI (P = 0.033) or hemoabdomen specifically (P = 0.0033). Overall survival to discharge was 89%, which was significantly greater than survival in dogs with pelvic injury that also had septic abdomen (33%; P = 0.0299). CONCLUSIONS: IA is common in dogs with pelvic fractures, especially those with sacral fractures. Pelvic fracture characterization had no bearing on the presence of IA.

Retrospective evaluation of xylitol ingestion in dogs: 192 cases (2007-2012).

OBJECTIVE: To summarize the signalment, clinical signs, prevalence of decreased blood glucose concentration (BG), prevalence of increased liver values, treatment, and outcome in dogs known to have ingested xylitol. DESIGN: Retrospective study from December 2007 to February 2012 SETTING: Three university teaching hospitals. ANIMALS: One hundred ninety-two client-owned dogs with known or suspected xylitol ingestion. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The median ingested xylitol dose was 0.32 g/kg (range 0.03-3.64 g/kg). Clinical signs were present in 39 (20%) dogs on presentation to the veterinary teaching hospitals. The most common clinical sign was vomiting (n = 25), followed by lethargy (12). The median duration of clinical signs prior to presentation was 93 minutes (range 0-5,040 minutes). Dogs that developed clinical signs ingested a significantly higher dose of xylitol than those that were asymptomatic. Thirty dogs became hypoglycemic (BG ≤ 3.3 mmol/L [60 mg/dL]) at some time point during their hospitalization. When evaluating all dogs, there was a significant difference between the initial and lowest BGs. Thirty dogs had increased alanine aminotransferase activity or total serum bilirubin concentration. Dogs with increases in alanine aminotransferase activity or total serum bilirubin concentration had a significantly lower nadir BG. All dogs survived to discharge and 158 were known to be alive at 28 days. The rest were lost to follow up. CONCLUSIONS: The prognosis for dogs evaluated by a veterinarian that ingest lower doses of xylitol and do not develop liver failure is excellent. Dogs ingesting xylitol should be hospitalized and monitored for variations in BG, because BG drops in most dogs following presentation. Additional studies are needed in dogs ingesting higher doses of xylitol before correlations between dose and the development of clinical signs or liver failure can be established. Treatment and prognosis for these dogs warrants further investigation.

Effect of sorbitol, single, and multidose activated charcoal administration on carprofen absorption following experimental overdose in dogs.

OBJECTIVE: To compare the effectiveness of single dose activated charcoal, single dose activated charcoal with sorbitol, and multidose activated charcoal in reducing plasma carprofen concentrations following experimental overdose in dogs. DESIGN: Randomized, four period cross-over study. SETTING: University research setting. ANIMALS: Eight healthy Beagles. INTERVENTIONS: A 120 mg/kg of carprofen was administered orally to each dog followed by either (i) a single 2 g/kg activated charcoal administration 1 hour following carprofen ingestion (AC); (ii) 2 g/kg activated charcoal with 3.84 g/kg sorbitol 1 hour following carprofen ingestion (ACS); (iii) 2 g/kg activated charcoal 1 hour after carprofen ingestion and repeated every 6 hours for a total of 4 doses (MD); (iv) no treatment (control). MEASUREMENTS AND MAIN RESULTS: Plasma carprofen concentrations were obtained over a 36-hour period following carprofen ingestion for each protocol. Pharmacokinetic modeling was performed and time versus concentration, area under the curve, maximum plasma concentration, time to maximum concentration, and elimination half-life were calculated and compared among the groups using ANOVA followed by Tukey's multiple comparisons test. Activated charcoal, activated charcoal with sorbitol (ACS), and multiple-dose activated charcoal (MD) significantly reduced the area under the curve compared to the control group. AC and MD significantly reduced the maximum concentration when compared to the control group. MD significantly reduced elimination half-life when compared to ACS and the control group. There were no other significant differences among the treatment groups. CONCLUSIONS: Activated charcoal and ACS are as effective as MD in reducing serum carprofen concentrations following experimental overdose in dogs. Prospective studies are warranted to evaluate the effectiveness of AC, ACS, and MD in the clinical setting.

Evaluation of two point-of-care ethylene glycol tests for dogs.

OBJECTIVE: To evaluate 2 point-of-care ethylene glycol (EG) tests in dogs. DESIGN: Prospective, randomized, blinded laboratory evaluation. SETTING: University teaching hospital. ANIMALS: Ten healthy adult dogs. INTERVENTIONS: Jugular venipuncture and in vitro evaluation for detection of EG in canine blood. MEASUREMENTS: Whole blood samples were centrifuged and separated, and the plasma was divided into 30 aliquots. The aliquots were mixed with EG to provide EG concentrations ranging from 0 to 100 mg/dL. The EG concentration of each sample was confirmed using gas chromatography. For the VetSpec EG Qualitative Reagent Test Kit, 100 µL of each sample was added to test vials and compared with 20 and 50 mg/dL reference vials. For the Kacey EG Test Strips, 20 µL of each sample was added to the test circle and compared with the color chart provided by the manufacturer. For each test, samples were prepared in groups of 5 and presented in randomized order to 2 readers who were blinded to the presumed EG concentration. Samples were scored as negative, 20-50 mg/dL, or greater than 50 mg/dL. For each test, the sensitivity and specificity for detecting EG was calculated. Cohen's unweighted kappa coefficient was calculated to determine the degree of agreement between readers. MAIN RESULTS: For detecting EG, the Kacey EG Test Strips had excellent sensitivity and specificity (both 100%) and good agreement between readers. The VetSpec EG Qualitative Reagent Test Kit was less sensitive and specific (65% and 70% for the first reader, 95% and 40% for the second) with less agreement. CONCLUSIONS: Of the 2 systems evaluated, the Kacey EG Test Strips displayed greater accuracy and ease of use.

The effects of protamine sulfate on clot formation time and clot strength thromboelastography variables for canine blood samples.

OBJECTIVE: To determine the effects of protamine sulfate on clot formation time and clot strength thromboelastography variables for canine whole blood samples. ANIMALS: Blood samples obtained from 11 healthy dogs. PROCEDURES: Blood samples were collected from jugular veins of dogs into syringes with 3.2% sodium citrate (blood to citrate ratio, 9:1). Blood samples were divided into aliquots, and protamine sulfate was added to various concentrations (0 [control], 22, 44, and 66 µg/mL). Prepared samples were activated with kaolin (n = 8) or not activated (8), CaCl2 was added, and thromboelastography was performed. Reaction time (R), clot formation time (K), rate of clot formation (α angle), and maximum amplitude (MA) were measured. RESULTS: For kaolin-activated and nonactivated blood samples, protamine (66 µg/mL) significantly increased R and K and decreased α angle and MA, compared with values for control samples. Also, protamine (44 µg/mL) decreased MA in nonactivated blood samples and increased K and decreased α angle in kaolin-activated samples, compared with values for control samples. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated protamine prolonged clot formation time and decreased overall clot strength in a dose-dependent manner; such effects may contribute to a hypocoagulable state in dogs. Kaolin-activated and nonactivated blood samples were appropriate for measurement of the effects of protamine on coagulation. Administration of protamine to reverse the effects of heparin should be performed with caution.

Systematic evaluation of evidence on veterinary viscoelastic testing part 2: Sample acquisition and handling.

OBJECTIVE: To examine systematically the evidence on sample acquisition and handling for the thrombo elastography (TEG) and rotational thromboelastometry (ROTEM) viscoelastic point of care instruments and to identify knowledge gaps. DESIGN: Six questions were considered, addressing sampling site, collection system, anticoagulant, collection procedure, and sample storage. Standardized, systematic evaluation of the literature was performed. Relevant articles were categorized according to level of evidence (LOE). Consensus was developed regarding conclusions for application of concepts to clinical practice. SETTING: Academic and referral veterinary medical centers. RESULTS: PubMed and CAB abstracts were searched. Eighteen papers were initially chosen; 5 of these papers applied to > 1 domain question. Three papers were used to address 2 questions each, and 2 papers were used to address 3 questions each. Most papers were judged LOE 3 (Good or Fair). Two of 5 papers were judged to be the same LOE each time they were used; 2 papers were judged to be LOE 3, Fair for 1 question and 3, Good for a second question; 1 paper used to address 3 questions was judged LOE 3, Good twice and 3, Fair once. Fourteen additional papers were evaluated post hoc during manuscript preparation. CONCLUSIONS: Jugular venipuncture is recommended, but samples from IV catheters can be used. Consistent technique is important for serial sampling, and standardized sampling protocols are recommended for individual centers performing TEG/ROTEM. There is insufficient evidence to recommend use of a specific blood collection system, although use of evacuated blood tubes and 21-Ga or larger needles is suggested. Use of 3.2% buffered sodium citrate in a strict 1:9 ratio of citrate to blood is suggested. Suggested tube draw order is discard/serum, followed by citrate, EDTA, and then heparin. Samples should be held at room temperature for 30 minutes prior to analysis.

Effect of venipuncture quality on thromboelastography.

OBJECTIVE: To determine if the quality of venipuncture impacts thromboelastography (TEG) results and if an initial discard tube mitigates any effects of traumatic venipuncture. DESIGN: Prospective, observational study. SETTING: Veterinary teaching hospital. ANIMALS: Fifteen privately owned and research colony adult dogs. MEASUREMENTS: Samples were collected from each jugular vein using 1 of 2 venipuncture techniques per vein. The venipuncture technique was randomized to the vein as follows: (1) "clean" venipuncture (CV) from 1 jugular vein, and (2) suboptimal venipuncture (SOV) from the opposite jugular vein. CV was defined as a direct entry into the vein on the first attempt. SOV was defined as needle insertion adjacent to the vein with redirection at least once to enter the vein. Two consecutive samples were collected from each venipuncture without removal of the needle, yielding 4 samples: CV1, CV2, SOV1, and SOV2. TEG was performed on each blood sample and the TEG parameters R, K, α, and MA were recorded. RESULTS: Mean ± SD of R for the SOV1 group (4.1 ± 1.3 s) was significantly shorter than that of the CV1 group (5.7 ± 1.4 s) and the SOV2 group (5.5 ± 1.9 s), P< 0.05. There was no difference in R between CV1 and CV2 groups, or between SOV2 and either CV1 or CV2. There was no significant difference in α, K, or MA among groups. CONCLUSIONS: Mild-to-moderate venipuncture trauma had little effect on TEG overall, but R was significantly affected. Poorer quality collection resulted in a more rapid initiation of clot formation. However, the effect was mild and mitigated by testing samples in a second collection tube after discard of an initial sample.

Effects of delayed anticoagulation and use of evacuated tubes on non-activated thrombelastography in dogs.

BACKGROUND: The effects of delayed anticoagulation and use of evacuated vacuum tubes in the collection of whole blood for nonactivated thrombelastography (TEG) are not known. OBJECTIVES: The objective of this study was to examine the effects of delayed anticoagulation and use of vacuum-assisted blood collection tubes on results of nonactivated TEG. METHODS: Twelve clinically healthy adult dogs were used in each of 3 studies. For each study, nonactivated TEG results from paired blood samples were compared. In study 1, the effect of delayed citrate anticoagulation was evaluated by collecting samples either into syringes containing citrate or into empty syringes followed by transfer to nonevacuated tubes containing citrate. In study 2, the effect of vacuum assistance in blood transfer was evaluated by collecting samples into syringes containing citrate and transferring either to nonevacuated plastic tubes or to evacuated plastic tubes. In study 3, the combined effects of delayed anticoagulation and vacuum assistance in blood transfer were evaluated by collecting samples into syringes containing citrate or into empty syringes followed by transfer to evacuated tubes containing citrate. Thrombelastographic analysis was performed in duplicate at 39°C after a 40-minute rest period. RESULTS: The collection methods that delayed anticoagulation and/or used evacuated tubes yielded samples that appeared more coagulable compared with samples not exposed to delay or evacuated tubes. CONCLUSION: Methods by which samples are collected affect results of nonactivated TEG and should be considered when establishing reference intervals, interpreting results, and publishing TEG results.