New-onset organ dysfunction as a screening tool for the identification of sepsis and outcome prediction in dogs with systemic inflammation

Introduction

Sepsis in people is defined as a life-threatening organ dysfunction (OD) caused by a dysregulated host response to infection. In veterinary medicine, sepsis is still defined by the presence of systemic inflammation plus the evidence of infection. Based on recent veterinary studies, multiorgan dysfunction syndrome (MODS) has been associated with a worse outcome in sepsis. Thus, the screening for OD is warranted to identify the most critically ill patients. The aim of this study was to investigate the diagnostic value of new-onset OD for the prediction of sepsis and outcome in a population of critically ill dogs with systemic inflammation.

Materials and methods

Dogs admitted to the Emergency Room and/or the Intensive Care Unit with systemic inflammation, defined by a serum C-reactive protein concentration > 1.6 mg/dL, were retrospectively included. Enrolled dogs were categorized according to the presence of sepsis or non-infectious systemic inflammation. The presence of newly diagnosed OD was assessed based on criteria adapted from human literature and previously reported canine criteria.

Results

275 dogs were included: 128 had sepsis and 147 had non-infectious systemic inflammation. The frequency of new-onset OD was not different between these groups. Only the presence of fluid-refractory hypotension was significantly associated with a diagnosis of sepsis (OR 10.51, 3.08-35.94; p < 0.0001). The frequency of at least two ODs was significantly higher in non-survivors compared to survivors, according to both the human and the veterinary criteria considered for the study (p = 0.0001 and p = 0.0004, respectively). Specifically, the presence of acute kidney injury, stupor or coma, prolonged Prothrombin Time and decreased Base Excess were associated with a higher risk of death in the multivariate binary logistic regression.

Discussion

In this population of critically ill dogs with systemic inflammation, the detection of newly diagnosed ODs was not able to predict sepsis diagnosis, other than the presence of fluid-refractory hypotension. However, given the strong prognostic significance associated with ODs, our results support the early screening for ODs in any severe inflammatory critical care condition to identify high-risk patients and optimize their management.

Defining sepsis in small animals

OBJECTIVE

To discuss the definitions of sepsis in human and veterinary medicine.

DESIGN

International, multicenter position statement on the need for consensus definitions of sepsis in veterinary medicine.

SETTING

Veterinary private practice and university teaching hospitals.

ANIMALS

Dogs and cats.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Sepsis is a life-threatening condition associated with the body's response to an infection. In human medicine, sepsis has been defined by consensus on 3 occasions, most recently in 2016. In veterinary medicine, there is little uniformity in how sepsis is defined and no consensus on how to identify it clinically. Most publications rely on modified criteria derived from the 1991 and 2001 human consensus definitions. There is a divergence between the human and veterinary descriptions of sepsis and no consensus on how to diagnose the syndrome. This impedes research, hampers the translation of pathophysiology insights to the clinic, and limits our abilities to optimize patient care. It may be time to formally define sepsis in veterinary medicine to help the field move forward. In this narrative review, we present a synopsis of prior attempts to define sepsis in human and veterinary medicine, discuss developments in our understanding, and highlight some criticisms and shortcomings of existing schemes.

CONCLUSIONS

This review is intended to serve as the foundation of current efforts to establish a consensus definition for sepsis in small animals and ultimately generate evidence-based criteria for its recognition in veterinary clinical practice.

Evaluation of the Effect of Induced Endotoxemia on ROTEM S® and Platelet Parameters in Beagle Dogs Anaesthetized with Sevoflurane

Endotoxemia is thought to induce severe changes in coagulation status. In this study, blood samples from six beagle dogs receiving 1 mg/kg E. coli lipopolysaccharide (LPS) intravenously were analyzed to describe the concurrent changes in platelet count, platelet function assessed with impedance thromboaggregometry, thromboelastometry and d-dimers during artificially induced endotoxemia and its therapy with fluids and vasopressors at five timepoints (baseline, after LPS and 30 mL/kg Ringer's acetate, during noradrenaline ± dexmedetomidine infusion, after a second fluid bolus and a second time after vasopressors). Results were analyzed for changes over time with the Friedman test, and statistical significance was set at p < 0.05. We found decreased platelet count and function and changes in all platelet-associated rotational thromboelastometry (ROTEM) variables indicating hypocoagulability, as well as increases in d-dimers indicating fibrinolysis within one hour of intravenous administration of LPS, with partial recovery of values after treatment and over time. The fast changes in platelet count, platelet function and ROTEM variables reflect the large impact of endotoxemia on the coagulation system and support repeated evaluation during the progress of endotoxemic diseases. The partial recovery of the variables after initiation of fluid and vasopressor therapy may reflect the positive impact of the currently suggested therapeutic interventions during septic shock in dogs.

Aetiology, clinical parameters and outcome in 113 dogs surgically treated for septic peritonitis (2004-2020)

BACKGROUND

Septic peritonitis (SP) is a common life-threatening condition. The aims of this study were to describe the aetiology, clinicopathological abnormalities, complications, treatment, outcome and prognosis of dogs with SP.

METHODS

Records of 113 dogs diagnosed and surgically treated for SP between 2004 and 2020 were reviewed.

RESULTS

Overall survival rate was 74.3%. Parameters at presentation that were significantly associated with mortality were lateral recumbency (p = 0.001) and elevated respiratory rate (p = 0.045). Hypotension during or after surgery (p < 0.001), liver injury (p < 0.001) and acute kidney injury (p < 0.001) were also more common in non-survivors. The source of contamination, number of surgeries or the location of perforation in cases of gastrointestinal tract perforation were not associated with mortality. Delta glucose (serum vs. abdominal) was available in 36 out of 113 dogs and the difference was more than 20 mg/dl in only 22 of out 36 (61.1%) cases.

CONCLUSION

Liver and kidney injuries play a role in mortality, and early diagnosis and intervention are recommended to prevent multiple organ dysfunction and death. The reported high sensitivity of delta glucose is questionable in diagnosis of SP.

Increased thrombin activatable fibrinolysis inhibitor activity is associated with hypofibrinolysis in dogs with sepsis

Introduction

Disorders of coagulation are well-recognized in dogs with sepsis, but data regarding fibrinolysis disorders are limited. We aimed to characterize fibrinolysis in dogs with sepsis compared to healthy controls. We hypothesized that dogs with sepsis would be hypofibrinolytic, and that hypofibrinolysis would be associated with non-survival.

Methods

This was a prospective observational cohort study. We enrolled 20 client-owned dogs with sepsis admitted to the Cornell University Hospital for Animals and 20 healthy pet dogs. Coagulation and fibrinolytic pathway proteins including antiplasmin activity (AP), antithrombin activity (AT), thrombin activatable fibrinolysis inhibitor activity (TAFI), D-dimer concentration, fibrinogen concentration, and plasminogen activity were measured and compared between groups. Overall coagulation potential, overall fibrinolysis potential, and overall hemostatic potential were calculated from the curve of fibrin clot formation and lysis over time.

Results

Compared to healthy controls, dogs with sepsis had lower AT (P = 0.009), higher AP (P = 0.002), higher TAFI (P = 0.0385), and higher concentrations of fibrinogen (P < 0.0001) and D-dimer (P = 0.0001). Dogs with sepsis also had greater overall coagulation potential (P = 0.003), overall hemostatic potential (P = 0.0015), and lower overall fibrinolysis potential (P = 0.0004). The extent of fibrinolysis was significantly negatively correlated with TAFI. No significant differences were observed between survivors and non-survivors.

Discussion

Dogs with sepsis were hypercoagulable and hypofibrinolytic compared to healthy dogs, suggesting potential utility of thromboprophylaxis in this patient population. The association between high TAFI and low overall fibrinolysis potential might provide a potential mechanism for this hypofibrinolysis.

Correlation Between D-Dimer Concentrations and Thromboelastography in Dogs With Critical Illness: A Retrospective, Cross-Sectional Study

A hospital-based, retrospective, cross-sectional study was performed to assess the correlation of kaolin-activated thromboelastography (TEG) with D-dimer concentrations in 59 dogs with critical illness. Dogs were included if they had one or more serious disease detected upon performing TEG and D-dimer concentration determination based on the same blood sample. According to the coagulation index (CI), the 59 dogs were divided into two groups: a hypercoagulable state, with CI > 4 (44 dogs) and a normocoagulable state, with CI < 4 (15 dogs). Moreover, the 44 dogs with CI > 4 were divided into three sub-groups according to the disease etiology, i.e., inflammatory/tumor (I/T: 25 dogs), hemodynamic compromise (H: 11 dogs), and both conditions (I/TH: 8 dogs). The median values (interquartile ranges) of the CI and D-dimer concentration were 5.46 (4.55–6.33) and 410.25 (74.63–2206.12) in the 44 dogs with CI > 4 and 3.29 (2.92–3.75) and 1164.7 (50–2250.05) in the 15 dogs with CI < 4, respectively. The D-dimer concentration was significantly increased over the reference value in the 44 dogs with a CI > 4, particularly in dogs in the I/T group. It was also significantly increased in the 15 dogs with a CI < 4. D-dimer concentrations did not correlate with any of the TEG parameters in any of the dogs. Given this lack of correlation, the D-dimer concentration may be limited as an indicator of a possible hypercoagulable state in dogs with critical illness.

A feasibility study investigating the utility of a point-of-care rapid immunoassay for detecting septic peritoneal effusion in dogs

OBJECTIVE

To determine the sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy of a point-of-care urine bacterial rapid immunoassay (RIA) for a diagnosis of septic peritonitis, compared to more traditional diagnostic tools, such as cytology and bacterial culture.

DESIGN

Prospective, cross-sectional feasibility study conducted from October 2016 to June 2017.

SETTING

Four locations within a private practice referral hospital.

ANIMALS

Sixty-four dogs with peritoneal effusion of any etiology were enrolled. Four dogs were excluded due to absent RIA or bacterial culture results. Two additional dogs were excluded because of an inability to definitively classify them as having septic peritonitis.

INTERVENTIONS

Abdominocentesis was performed to obtain peritoneal effusion samples for aerobic and anaerobic bacterial culture, cytology, and RIA. Cytological slides were evaluated by a clinical pathologist following enrollment.

MEASUREMENTS AND MAIN RESULTS

Fifty-eight dogs were included in the study, 8 of which were classified as having septic peritonitis. Compared to final diagnosis of septic peritonitis, RIA had a low PPV (36.8%) but good NPV (97.4%) and was 77.5% accurate. SN of RIA (87.5%) to diagnose septic peritonitis was similar to cytology (85.7%) and bacterial culture (87.5%); however, SP was lower (76%, 100%, and 98%, respectively). Cytology had the best overall predictive values and accuracy for diagnosing septic peritonitis (PPV 100%, NPV 97.9%, and accuracy 98%) compared to RIA and bacterial culture.

CONCLUSIONS

RIA testing was similarly sensitive in identifying septic peritonitis compared to cytology and bacterial culture but was not very specific or accurate. As a stand-alone test, RIA commonly had false-positive test results, making it unreliable in identifying septic peritonitis. Cytology was the most accurate diagnostic test and had no false-positive results. Further investigation with a larger sample size and prevalence of septic peritonitis may prove beneficial.

Lipopolysaccharide-Activated Canine Platelets Upregulate High Mobility Group Box-1 via Toll-Like Receptor 4

High mobility group box-1 (HMGB1) and the toll-like receptor 4 (TLR4) axis is a key mediator of inflammation. Platelet-derived high mobility group box-1 (HMGB1) may also play a critical role in sepsis-mediated thrombosis resulting in complications like disseminated intravascular coagulation and multiple organ failure. While elevated levels of HMGB1 have been documented in humans and dogs with systemic inflammatory response syndrome and sepsis, a better understanding of how platelet agonists and lipopolysaccharide (LPS) mediate platelet HMGB1 expression would open doors to novel therapies for sepsis-mediated thrombosis. Herein, we sought to determine if canine platelets express HMGB1 in the presence or absence of LPS and agonists (ADP or thrombin) and if surface expression of HMGB1 is dependent on platelet TLR4. Canine platelets were unstimulated (resting) or activated with thrombin or adenosine diphosphate (ADP) in the presence or absence of Escherichia coli LPS prior to flow cytometric and western blot analyses for HMGB1 expression. We also treated canine platelets with or without TLR4 function blocking antibody or its isotype control. We discovered that while thrombin upregulated both surface and cellular HMGB1 expression, LPS-mediated activation in the presence of ADP priming led to upregulation of surface HMGB1 expression. This expression was found to be most prominent in platelets that had undergone alpha-granule secretion. Inhibition of TLR4 attenuated LPS-induced HMGB1 expression indicating that exteriorization of HMGB1 may be dependent on the non-genomic pathway of platelet TLR4. Our findings indicate that upregulation of platelet-derived HMGB1 occurs as a result of thrombin or TLR4-mediated activation in dogs. Future studies should explore the translational implication of platelet-derived HMGB1 as novel therapeutic targets in humans and dogs with sepsis.

Fluid Resuscitation for Refractory Hypotension

Hypotension is a common occurrence, especially in anesthetized patients and in critical patients suffering from hypovolemia due to shock and sepsis. Hypotension can also occur in normovolemic animals, anesthetized or conscious, under conditions of vasodilation or decreased cardiac function. The main consequence of hypotension is decreased organ perfusion and tissue injury/dysfunction. In the human literature there is no consensus on what is the threshold value for hypotension, and ranges from < 80 to < 100 mmHg for systolic blood pressure and from < 50 to < 70 mmHg for mean arterial blood pressure have been referenced for intraoperative hypotension. In veterinary medicine, similar values are referenced, despite marked differences in normal arterial blood pressure between species and with respect to humans. Therapeutic intervention involves fluid therapy to normalize volemia and use of sympathomimetics to enhance cardiac function and regulate peripheral vascular resistance. Despite these therapeutic measures, there is a subset of patients that are seemingly refractory and exhibit persistent hypotension. This review covers the physiological aspects that govern arterial blood pressure control and blood flow to tissues/organs, the pathophysiological mechanisms involved in hypotension and refractory hypotension, and therapeutic considerations and expectations that include proper interpretation of cardiovascular parameters, fluid recommendations and therapy rates, use of sympathomimetics and vasopressors, and newer approaches derived from the human literature.

Use of Thromboelastography in Clinical Practice

Viscoelastic testing, such as thromboelastography or thromboelastometry, is performed on whole-blood samples, which include both soluble plasma factors as well as blood cells and platelets bearing tissue factor and phospholipid. This methodology allows identification of fibrinolysis and can provide analysis of platelet function. Viscoelastic testing has become increasingly accessible and popular in emergency and critical care settings in recent years and can provide important information for the diagnosis and management of patients with hemostatic disorders. This article discusses the principles and interpretation of viscoelastic testing, application to small animal emergency and critical care medicine, and potential advantages and disadvantages.

Glucocorticoid metabolism in critically ill dogs (Canis lupus familiaris)

Critical illness due to sepsis is a major global health concern associated with a high burden of mortality and cost. Glucocorticoid dysregulation in human sepsis is associated with poorer outcomes. This study examines glucocorticoid metabolism in septic canine patients to delineate elements of cellular dysregulation in common with critically ill humans and explore potential differences. This was a prospective case-control study conducted in the veterinary specialist critical care departments of two University teaching hospitals. Critically ill canine patients with naturally occurring sepsis or septic shock were compared with an in-hospital control population. Serum total, bound, and free cortisol concentrations were increased in septic shock (P < 0.001), and higher bound cortisol was associated with nonsurvival (P = 0.026). Urinary Gas Chromatography-Tandem Mass Spectrometry was performed to assess urinary glucocorticoid metabolites and estimate intracellular glucocorticoid metabolism. Decreased renal 11β-hydroxysteroid dehydrogenase 2 (11βHSD2) activity inferred from increased urinary cortisol-to-cortisone ratio was observed in critically ill dogs (P < 0.001). Decreased 11βHSD2 activity (P = 0.019) and increased A-ring reduction of cortisone (P = 0.001) were associated with nonsurvival within the critically ill dogs. Intriguingly, two dogs were identified with low circulating total cortisol (<2 mg/dL) associated with increased A-ring reduction of cortisol, not previously described. Investigation of spontaneous canine sepsis and septic shock reveals dysregulation of cortisol to cortisone conversion similar to that observed in human patients, but with differences in A-ring reduction compared with those reported in humans. In addition, two dogs with high levels of cortisol inactivation associated with low circulating cortisol concentrations were identified.

Biomarker Guided Diagnosis of Septic Peritonitis in Dogs

Septic peritonitis (SP) is common in dogs and is associated with high mortality. Early recognition is essential to maximizing survival and may be aided by biomarker measurement. The present study aimed to evaluate the ability of biomarkers to discriminate septic peritonitis from non-septic ascites (NSA). Eighteen dogs with SP and 19 age-matched controls with NSA were enrolled. Contemporaneous blood and peritoneal effusion samples were obtained. Concentrations of cell-free DNA (cfDNA), cytokines, glucose, lactate, N-terminal pro-C-type natriuretic peptide (NT-proCNP), nucleosomes, and procalcitonin (PCT) were measured using commercial reagents and assays. Paired biomarker concentrations were compared with the Wilcoxon matched-pairs signed rank test, and biomarker concentrations between groups were compared with the Mann-Whitney U-test. P-values were adjusted for multiple comparisons using the Bonferroni correction. Receiver operating characteristic curves were generated to assess the ability of the above biomarkers to discriminate SP from NSA. Dogs with SP had significantly greater blood CCL2 concentrations than dogs with NSA (P = 0.032). Dogs with SP had significantly greater effusion CCL2, IL-6, IL-10, and lactate concentrations than dogs with NSA (P ≤ 0.0121). Blood-effusion concentration gradients of CCL2, glucose, IL-6, IL-10, and lactate were significantly different in dogs with SP compared to dogs with NSA (P ≤ 0.0165). Effusion lactate concentration had the highest AUROC value (0.866, 95% CI 0.751–0.980, P = 0.0001), although other biomarkers performed similarly. An effusion lactate concentration of 4.2 mmol/L was 72.2% (95% CI 46.5–90.3%) sensitive and 84.2% (95% CI 60.4–96.6%) specific for the diagnosis of SP.

Multicenter investigation of hemostatic dysfunction in 15 dogs with acute pancreatitis

OBJECTIVE

To characterize hemostatic profiles in dogs with acute pancreatitis.

DESIGN

Prospective and observational study.

SETTING

Tertiary referral centers.

ANIMALS

Fifteen client-owned dogs with acute pancreatitis enrolled between December 1, 2011 and June 1, 2012.

MATERIALS AND METHODS

Blood samples were collected on admission for measurement of platelet count, PCV, thromboelastography (TEG), antithrombin, prothrombin time, activated partial thromboplastin time, D-dimer, von Willebrand factor, and fibrinogen values, which were compared to reference intervals derived from healthy dogs. The Wilcoxon rank-sum test was used to test for differences in continuous variables between study subjects and reference intervals.

MEASUREMENTS AND MAIN RESULTS

Dogs with acute pancreatitis were globally hypercoagulable using TEG when compared with reference intervals. Dogs with acute pancreatitis had significantly higher D-dimers (1,144 μg/L vs 251 μg/L [6264.5 vs 1374.5 nmol/L]; P = 0.001), fibrinogen (837 vs 232 mg/dL [8.37 vs 2.32 g/L]; P < 0.001), and von Willebrand factor (92.9% vs 65.1%; P = 0.02) as well as significantly lower antithrombin (85.7% vs 120%; P < 0.001) and prothrombin time values (3.8 vs 7.6 sec; P < 0.001) than reference intervals.

CONCLUSIONS

Laboratory evidence of hypercoagulability was present in dogs with acute pancreatitis. TEG may be useful in dogs with acute pancreatitis for monitoring response to therapy and guiding therapeutic interventions.

Clinical use of cryopoor plasma continuous rate infusion in critically ill, hypoalbuminemic dogs

OBJECTIVE

To investigate the impact of cryopoor plasma (CPP) continuous rate infusion (CRI) on albumin concentration and colloid osmotic pressure (COP) in critically ill dogs with hypoalbuminemia.

DESIGN

Retrospective study between 2013 and 2015 with a 90-day follow-up on survivors.

SETTING

University teaching hospital.

ANIMALS

Ten hypoalbuminemic dogs receiving a CPP CRI for albumin replacement or oncotic support. All patients with documented hypoalbuminemia or low COP receiving CPP administration for albumin or oncotic support during the study period were included.

INTERVENTIONS

CRI of CPP.

MEASUREMENTS AND MAIN RESULTS

Mean age was 7.4 ± 4.5 years. Mean survival prediction index score was 0.66 ± 0.13. Seven dogs were septic, with 2 of 7 in septic shock and 5 of 7 having septic peritonitis. The mean pre- and postinfusion albumin was 15 ± 4 g/L and 21 ± 2 g/L, respectively. The median pre- and postinfusion COP was 8.6 mm Hg (4.9-9.7 mm Hg) and 10.2 mm Hg (8.1-13.3 mm Hg), respectively. The median duration of CRI was 16 hours (11-121 h). The mean CPP rate was 1.8 ± 0.6 mL/kg/h, the mean crystalloid rate administered concurrently was 0.8 ± 0.9 mL/kg/h, and the mean hydroxyethyl starch rate administered concurrently was 1.2 ± 0.9 mL/kg/h. The difference in pre- and postinfusion albumin was significantly correlated with CPP rate (P = 0.0004), whereas the difference in pre- and postinfusion COP was correlated with hydroxyethyl starch rate (P = 0.0128). Mean duration of hospitalization was 8.6 ± 3.9 days. Mann-Whitney U and Fisher's exact tests were used to compare survivors and nonsurvivors. Survivors were significantly younger than nonsurvivors (3.5 vs 11.5 y, P = 0.033). No side effects were reported. Survival to discharge was 40% with identical 90-day survival. Of the nonsurvivors, 50% died naturally.

CONCLUSIONS

There was an association between the rate of CPP and the change in albumin after CPP CRI in critically ill dogs, suggesting that CPP may be a viable option for treatment of hypoalbuminemia.

Aggregating resistant Staphylococcus aureus induces hypocoagulability, hyperfibrinolysis, phagocytosis, and neutrophil, monocyte, and lymphocyte binding in canine whole blood

BACKGROUND

Staphylococcus aureus is an opportunistic pathogen with the ability to form mobile planktonic aggregates during growth, in vitro. The in vivo pathophysiologic effects of S aureus aggregates on host responses are unknown. Knowledge of these could aid in combating infections.

OBJECTIVE

This study aimed to investigate the effect of increasing concentrations of two different aggregating S aureus strains on the hemostatic and inflammatory host responses in canine whole blood. The hypothesis was that aggregating bacteria would induce pronounced hemostatic and inflammatory responses.

METHODS

Citrate-stabilized whole blood from 10 healthy dogs was incubated with two strains of aggregating S aureus at three different concentrations. Each sample was analyzed using tissue factor-thromboelastography (TF-TEG) and the formed clot was investigated with electron microscopy. The plasma activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, and D-dimer tests were measured. Bacteria-leukocyte binding was evaluated with flow cytometry, and neutrophil phagocytosis was assessed using light and transmission electron microscopy.

RESULTS

The highest concentration of bacteria resulted in a significantly shortened TF-TEG initiation time, decreased alpha, maximum amplitude, global strength, and increased lysis. In addition, significantly shortened PT, decreased fibrinogen, and increased D-dimers were demonstrated at the highest concentration of bacteria. Lower concentrations of bacteria showed no differences in TF-TEG when compared with controls. The findings were similar for both S aureus strains. Increased concentration-dependent binding of bacteria and leukocytes and neutrophil bacterial phagocytosis was observed.

CONCLUSIONS

Two strains of S aureus induced alterations of clot formation in concentrations where bacterial aggregates were formed. A concentration-dependent cellular inflammatory response was observed.

Utility and Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Dogs with Septic Peritonitis

Systemic inflammation is known to cause WBC abnormalities, specifically neutrophilia and lymphopenia. The neutrophil-to-lymphocyte ratio (NLR) is a simple and affordable biomarker that has been used in human clinical settings of sepsis but has not been investigated in veterinary species. We evaluated NLR in dogs with septic and nonseptic systemic inflammatory diseases and compared with a healthy dog population. An NLR ≥6 had an 84.39% sensitivity and 86.95% specificity to identify dogs with systemic inflammatory states; however, no ratio distinguished septic and nonseptic causes. The NLR was not associated with length of hospitalization, morbidity based on the acute patient physiologic laboratory evaluation scoring system, or mortality. The disassociation may be due to the retrospective nature of the study, including a restricted population size and acquisition of only a one-time blood sample. NLR is currently of limited use for diagnosis and prognosis in systemic inflammatory states in dogs, and larger, prospective studies are necessary to further evaluate NLR.

Establishing a protocol for thromboelastography in sea turtles

Thromboelastography (TEG) provides a global evaluation of haemostasis. This diagnostic test is widely used in mammals but has not previously been performed in reptiles, mainly due to the limited availability of taxon-specific reagents. The objective of this pilot study was to establish a protocol to perform TEG in sea turtles. Pooled citrated plasma, stored at −80°C, from four green turtles (Chelonia mydas) was assayed on a TEG 5000. Several initiators were evaluated: kaolin (n=2), RapidTEG (n=2), fresh (n=2) and frozen (n=6) thromboplastin extracted from pooled brain tissue from several chelonian species, human recombinant tissue factor at 1:100 (n=1), Reptilase (n=2), and rabbit thromboplastin (n=1). Both fresh and frozen chelonian thromboplastin were superior in producing quantifiable TEG reaction time compared with all other reagents. These findings are consistent with the lack of an intrinsic pathway in turtles and confirmed a lack of coagulation in the turtle samples in response to mammalian thromboplastin. A TEG protocol was subsequently established for harvested species-specific frozen thromboplastin. The frozen thromboplastin reagent remained stable after one year of storage at −80°C. The developed protocol will be useful as a basis for future studies that aim to understand the pathophysiology of haemostatic disorders in various stranding conditions of sea turtles.

Retrospective evaluation of circulating thyroid hormones in critically ill dogs with systemic inflammatory response syndrome

Critical illness can be associated with transient alterations in circulating thyroid hormone concentrations, indicating the presence of non-thyroidal illness (NTI). NTI is well described in humans, but there are few reports on its occurrence and prognostic significance in dogs. This retrospective study assessed the occurrence of NTI in a population of dogs with systemic inflammatory response syndrome (SIRS) and investigated its association with disease severity (APPLE_fast scores). A total of 41 SIRS dogs were included and were divided by SIRS origin (non-septic SIRS, n = 10; septic SIRS, n = 41) and final outcome (survivors, n = 37; non-survivors, n = 4). Healthy, age-matched dogs (n = 15) were included as controls. Serum thyroid hormone levels including total T3, free T3, total T4, and reverse T3 were measured upon admission. Compared to controls, there were significant changes in serum thyroid hormone concentrations in SIRS dogs, suggesting the presence of NTI. Septic SIRS dogs had higher APPLE_fast scores and lower serum thyroid hormones concentrations than those in non-septic SIRS and control dogs. In conclusion, NTI was frequent in dogs with SIRS and may be associated with the presence of sepsis or high illness severity.

Clinical, laboratory, and hemostatic findings in cats with naturally occurring sepsis

OBJECTIVE To characterize clinical and laboratory findings in cats with naturally occurring sepsis, emphasizing hemostasis-related findings, and evaluate these variables for associations with patient outcomes. DESIGN Prospective, observational, clinical study. ANIMALS 31 cats with sepsis and 33 healthy control cats. PROCEDURES Data collected included history; clinical signs; results of hematologic, serum biochemical, and hemostatic tests; diagnosis; and outcome (survival vs death during hospitalization or ≤ 30 days after hospital discharge). Differences between cats with and without sepsis and associations between variables of interest and death were analyzed statistically. RESULTS The sepsis group included cats with pyothorax (n = 10), septic peritonitis (7), panleukopenia virus infection (5), bite wounds (5), abscesses and diffuse cellulitis (3), and pyometra (1). Common clinical abnormalities included dehydration (21 cats), lethargy (21), anorexia (18), pale mucous membranes (15), and dullness (15). Numerous clinicopathologic abnormalities were identified in cats with sepsis; novel findings included metarubricytosis, hypertriglyceridemia, and high circulating muscle enzyme activities. Median activated partial thromboplastin time and plasma D-dimer concentrations were significantly higher, and total protein C and antithrombin activities were significantly lower, in the sepsis group than in healthy control cats. Disseminated intravascular coagulopathy was uncommon (4/22 [18%] cats with sepsis). None of the clinicopathologic abnormalities were significantly associated with death on multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE Cats with sepsis had multiple hematologic, biochemical, and hemostatic abnormalities on hospital admission, including several findings suggestive of hemostatic derangement. Additional research including larger numbers of cats is needed to further investigate these findings and explore associations with outcome.

Evaluation of thromboelastography in bitches with pyometra

We investigated the effect of pyometra on kaolin-activated thromboelastography (TEG). Eighteen client-owned dogs with pyometra and 8 healthy spayed dogs were recruited. TEG parameters and packed cell volume were determined. Results from spayed females and from intact females with pyometra were compared using a Student t-test and Wilcoxon rank sum test. Bitches with pyometra were hypercoagulable compared to spayed bitches as evidenced by elevated maximum amplitude, G, and alpha angle. There were no significant group differences in R time, K time, or clot lysis at 30 or 60 min. Dogs with pyometra should be anticipated to have hypercoagulable TEG variables, and this should be addressed when planning surgical and medical therapy.

Identifying coagulopathies in the pathophysiology of cold stress syndrome in the Florida manatee Trichechus manatus latirostris

Cold stress syndrome (CSS) in the Florida manatee Trichechus manatus latirostris has been defined as morbidity and mortality resulting from prolonged exposure to water temperatures <20°C. The pathophysiology is described as multifactorial, involving nutritional, immunological and metabolic disturbances; however, the exact mechanisms are unknown. We hypothesized that thromboembolic complications contribute to the pathophysiology of CSS in addition to the previously described factors. During the winter of 2014-2015, 10 Florida manatees with clinical signs of CSS were presented to Lowry Park Zoo, Tampa, FL, USA. Thromboelastography (TEG) and coagulation panels were performed at admission. In addition, coagulation panel data from 23 retrospective CSS cases were included in the analyses. There were numerous differences between mean values of TEG and coagulation parameters for healthy manatees and those for CSS cases. Among TEG parameters, reaction time (R), clot formation time (K) and percentage of clot lysed after 30 min (LY30) values were significantly different (p < 0.05) between the 2 groups. CSS cases also had significantly higher mean D-dimer concentration and coagulation factor XI activity, prolonged mean activated partial thromboplastin time (aPTT) and significantly decreased mean antithrombin activity. These combined abnormalities include clinicopathologic criteria of disseminated intravascular coagulation, indicating an increased risk of thromboembolic disease associated with manatee CSS.

A pilot study evaluating the prognostic utility of platelet indices in dogs with septic peritonitis

OBJECTIVE

To characterize platelet indices at time of diagnosis of septic peritonitis in dogs and to assess the relationship between platelet parameter data and survival to discharge in dogs treated surgically.

DESIGN

Retrospective, observational, descriptive pilot study from 2009 to 2014.

SETTING

University teaching hospital.

ANIMALS

Forty-eight dogs diagnosed with septic peritonitis were included in this study. Thirty-six dogs had surgical source control. Blood samples from 46 healthy control dogs were used for reference interval (RI) generation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs with septic peritonitis had significantly increased mean values for mean platelet volume (MPV), plateletcrit (PCT), and platelet distribution width (PDW) with increased proportions of dogs having values above the RI compared to healthy dogs. A significantly increased proportion of dogs with septic peritonitis had platelet counts above (12.5%) and below (8.3%) the RI, with no significant difference in mean platelet count compared to healthy dogs. No significant differences in the mean platelet count, MPV, PCT, or PDW were found between survivors and nonsurvivors in dogs with surgical source control; however, dogs with MPV values above the RI had significantly increased mortality compared to dogs within the RI (P = 0.025). Values outside the RI for other platelet parameters were not associated with significant differences in mortality.

CONCLUSIONS

Dogs with septic peritonitis have increased frequency of thrombocytosis and thrombocytopenia with increased MPV, PCT, and PDW. An increased MPV may be a useful indicator of increased risk of mortality in dogs treated surgically.

Correlation between thromboelastography and traditional coagulation test parameters in hospitalized dogs

A hospital-based, prospective cross-sectional study was used to compare kaolin-activated thromboelastography (TEG) parameters with traditional coagulation tests in 29 hospitalized dogs. Cases were included if the attending clinician requested coagulation testing. Blood was obtained from each dog and coagulation (prothrombin time, partial thromboplastin time, antithrombin activity, d-dimer concentration, and fibrinogen concentration) and TEG analyses were performed. Hematocrit (Hct) was also measured. Traditional coagulation results were evaluated for correlation with those from kaolin-activated TEG. Spearman’s correlation was used to calculate correlation coefficients. Fibrinogen was positively correlated with maximum amplitude (Pearson r=0.72, P<0.001) and global clot strength (Pearson r=0.72, P<0.001). There was no correlation between any of the remaining coagulation variables, TEG parameters, or Hct. Results of kaolin-activated TEG and traditional coagulation tests are not interchangeable means of monitoring coagulation derangements in this intensive care unit patient population. Determination of a true outcome measure is necessary to establish TEG’s clinical relevance to veterinary medicine.

Establishment of reference values for various coagulation tests in healthy Florida manatees (Trichechus manatus latirostris) and evaluation of coagulation in debilitated manatees during rehabilitation

OBJECTIVE

To establish reference ranges for coagulation parameters in healthy Florida manatees (Trichechus manatus latirostris) and compare results with those for debilitated manatees undergoing treatment at a rehabilitation facility.

DESIGN

Prospective study.

ANIMALS

29 healthy manatees and 45 debilitated manatees with various diseases.

PROCEDURES

Manatees considered healthy on the basis of results of physical examination, CBC, and serum biochemical analysis underwent coagulation testing including measurement of prothrombin time, partial thromboplastin time, D-dimer concentration, platelet count, and fibrinogen concentration to establish reference ranges. For comparison, a group of manatees undergoing rehabilitation was also tested, and the results were compared. Thromboelastography was also performed on some animals.

RESULTS

Values for D-dimer concentration were significantly higher in debilitated versus healthy animals. There was no significant difference for prothrombin time, partial thromboplastin time, platelet count, or fibrinogen concentration between groups. Thromboelastography was performed on 8 healthy animals.

CONCLUSIONS AND CLINICAL RELEVANCE

Reference ranges were established for various tests of coagulation that may assist clinicians during the initial evaluation and rehabilitation of Florida manatees. Future research to evaluate the effect of specific disease processes on the coagulation cascade is recommended.

Evaluation of platelet function using multiple electrode platelet aggregometry in dogs with septic peritonitis

OBJECTIVE

To assess platelet function via multiple electrode platelet aggregometry (MEPA) in dogs with septic peritonitis and in healthy dogs. The secondary aim was to determine if there is prognostic significance to changes in platelet function observed in septic dogs.

DESIGN

Prospective, observational cohort study conducted from January 2012 to March 2014.

SETTING

University teaching hospital.

ANIMALS

Twenty dogs with septic peritonitis and 23 healthy dogs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

MEPA using arachidonic acid, adenosine diphosphate, and collagen (COL) as agonists was measured within 24 hours of diagnosis of sepsis. Compared to healthy dogs, platelet aggregation was reduced in dogs with septic peritonitis for all agonists (P < 0.01). Overall mortality rate was 40%. MEPA in response to COL was significantly reduced in nonsurvivors compared to survivors (P = 0.019). Using receiver-operating characteristic curve statistics, a COL-activated MEPA less than 43.5 aggregation units had a sensitivity and specificity of 85.7% and 90.9%, respectively, for predicting nonsurvival in dogs with septic peritonitis.

CONCLUSIONS

Circulating platelets from dogs with septic peritonitis have diminished aggregation in response to multiple platelet agonists. MEPA may serve as an assessment tool for illness severity in this patient population.

Retrospective comparison of thromboelastography results to postmortem evidence of thrombosis in critically ill dogs: 39 cases (2005-2010)

OBJECTIVE

To determine whether there is an association between thromboelastography (TEG) data and necropsy evidence of thrombosis in a cohort of critically ill dogs.

DESIGN

Retrospective study (2005-2010).

SETTING

University teaching hospital.

ANIMALS

Thirty-nine client-owned critically ill dogs for which TEG was performed within 7 days of complete necropsy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thrombi were found in 26 (67%) dogs. Spayed females (n = 20) were significantly more likely to have thrombosis (P = 0.0127). No significant association was found between presence of thrombosis and any TEG parameter, the calculated coagulation index, results of coagulation testing, type of vascular access, or clinical diagnosis. D-dimers were significantly higher in dogs with thrombosis (P = 0.0207) and a weak positive correlation was found between D-dimer value and number of sites of thrombosis (ρ = 0.18, P = 0.0045). Dogs with WBC > 16 × 10(3) /μL were more likely to have thrombosis compared to others (odds ratio 5.56, 95% confidence interval 1.2-25.7, P = 0.025).

CONCLUSIONS

This study found no association between any TEG parameter and the presence of thrombosis on postmortem examination.

Hemostatic variables, plasma lactate concentration, and inflammatory biomarkers in dogs with gastric dilatation-volvulus

OBJECTIVE

Prospective characterization of hemostastatic variables, plasma lactate concentration, and inflammatory biomarkers in dogs with gastric dilatation-volvulus (GDV).

MATERIAL AND METHODS

Coagulation variables (platelets, prothrombin time [PT], activated partial thromboplastin time [aPTT], fibrinogen, antithrombin [AT], protein C [PC], protein S [PS], D-dimers), plasma lactate concentration and inflammatory biomarkers (C-reactive protein, white blood cell [WBC] count, lymphocyte and neutrophil numbers) were assessed in 20 dogs with GDV presented between 2011 and 2012. Blood was taken preoperatively and at days 1 and 3 postoperatively. The prognostic value of these variables before and after surgery was evaluated as well as the behavior of variables during the study.

RESULTS

Overall, 7/20 (35%) dogs did not survive; two dogs (29%) were euthanized during surgery due to severe gastric necrosis and 5 (71%) dogs after surgery due to sepsis and disseminated intravascular coagulopathy. Prior to surgery, median plasma lactate concentration was significantly (p = 0.01) lower in survivors (6.2 mmol/l, range 1.9-9.7 mmol/l) when compared to non-survivors (11.8 mmol/l, range 7.5-16.2 mmol/l). In dogs dying after surgery, significantly higher plasma lactate concentration, coagulation times and D-dimer concentration were present as well as lower fibrinogen concentration and activity of PC and AT compared to survivors. At discharge, activity of AT, PC and PS were markedly below the reference interval in 6/13 (46%), 11/13 (85%), and 8/13 (62%) dogs, respectively.

CLINICAL RELEVANCE

Only lactate plasma concentration was of preoperative prognostic value. After surgery, severe abnormalities of coagulation variables, especially the endogenous anticoagulants were present in most of the dogs. The severity of the abnormalities was associated with survival.

Current diagnostic trends in coagulation disorders among dogs and cats

The diagnostic workup to differentiate hemorrhage caused by vascular injury from a systemic hemostatic imbalance typically involves a combination of broad screening tests and specific assays. The characterization of 3 overlapping phases of primary hemostasis, secondary hemostasis, and fibrinolysis provides a simple diagnostic framework for evaluating patients with clinical signs of hemorrhage. New techniques such as flow cytometry, thrombin-generation assays, thrombelastography, and anticoagulant drug monitoring are under investigation for veterinary patients; however, their ability to improve diagnosis or treatment requires further study in clinical trials.