Assessment of shock index in healthy cats and in cats presenting to an emergency room with shock

OBJECTIVE

To prospectively compare the shock index (SI) in a population of healthy cats with a population of cats presenting to the emergency room (ER) deemed to be in a state of shock.

DESIGN

Prospective cohort study of cats.

SETTING

University teaching hospital.

ANIMALS

Twenty-seven healthy control cats were enrolled to establish a reference interval, and 27 cats were enrolled that were presented to the ER with clinical signs of shock. Shock was defined as abnormalities in at least 2 of the following inclusion criteria: plasma lactate concentration > 2.5 mmol/L; peripheral vasoconstriction (at least 2 of the following parameters: capillary refill time >3 s, rectal-interdigital temperature gradient [RITG] >8°C, femoral pulse not palpable, pale mucous membranes); or systolic blood pressure (SBP) < 100 mm Hg.

INTERVENTIONS

Upon presentation, SI (SI = heart rate [HR]/SBP), HR, SBP, and RITG were recorded in both groups, along with peripheral venous blood sampling for lactate measurement.

MEASUREMENTS AND MAIN RESULTS

The mean SI in the control group was 1.47 ± 0.2 and was 1.87 ± 0.47 in the shock group (P = 0.001). Using equality in sensitivity and specificity of 0.7, an SI cutoff point of 1.54 (95% confidence interval [CI]: 0.49-0.86) was determined with an estimated area under the receiver operating characteristic curve of 0.78 (95% CI: 0.65-0.90). HR, plasma lactate concentration, and RITG did not differ between the groups. Systolic arterial blood pressure (P = 0.01), rectal temperature (P = 0.02), and interdigital temperature (P = 0.04) differed significantly.

CONCLUSIONS

The SI is a noninvasive, easy, and reliable parameter for distinguishing cats in shock from normal cats.

Clinical parameters at time of admission as prognostic indicators in cats presented for trauma to an emergency centre in New Zealand: a retrospective analysis

OBJECTIVES

The aims of this study were to describe the clinical features of cats presented for trauma in a first-opinion and referral teaching hospital in New Zealand, and to determine the relationship between those features and outcome.

METHODS

The electronic medical records of cats presented for trauma to the Massey University Pet Emergency Centre between September 2013 and January 2019 were examined, from which the signalment, clinical parameters and patient outcomes were extracted. Cases were assigned an Animal Trauma Triage (ATT) score and Modified Glasgow Coma Scale (MGCS) score. Variables were selected for inclusion in a logistic regression model to predict survival, and backward elimination was used to find the minimal significant model.

RESULTS

In total, 530 cats met the inclusion criteria. The cause of injury was not known in the majority of cases (38.0%). The most common location of injury was the hindlimbs/pelvis/tail (n = 247; 41%), and skin lacerations/abrasions were the most common specific injury. Multivariate analysis revealed altered mentation (odds ratio [OR] 0.31, P = 0.029), hypothermia (rectal temperature <37.8°C [<100.04°F]; OR 0.45, P = 0.015) and an ATT score ⩾5 (OR 0.13, P <0.001) to be statistically significantly associated with mortality.

CONCLUSIONS AND RELEVANCE

Altered mentation and hypothermia are easily measurable perfusion parameter abnormalities associated with mortality in cats presenting with trauma. The ATT score appears to be an accurate prognostic indicator in cats presenting with trauma in New Zealand. These results highlight the importance of incorporating a hands-on triage examination in each cat that presents as an emergency after trauma.

Prognostic value of lactate in cats presented in respiratory distress to the emergency room

Studies demonstrating the prognostic utility of plasma lactate concentration and lactate clearance in cats are limited. The objective of this study was to determine the prognostic utility of plasma lactate concentration upon admission and plasma lactate clearance in cats presented to the emergency room with respiratory distress attributed to underlying cardiac or respiratory disease. Additionally, we sought to determine if plasma lactate concentration on admission was significantly associated with the underlying cause of respiratory distress (cardiac vs. respiratory), type of respiratory disease, and vital parameters. Seventy-one cats presented in respiratory distress to the ER at a university teaching hospital were enrolled in this retrospective study. Admission lactate concentration was not associated with survival, duration of hospitalization, vital parameters, or underlying etiology for respiratory distress. In contrast, lactate clearance was significantly associated with survival and length of hospitalization. While a statistically significant association between lactate clearance and length of hospitalization was identified, this finding lacked clinical significance where an increase in lactate concentration by 1% was associated with an increased length of hospitalization by 11.4 min (p = 0.035). Results of this study suggest that lactate clearance may have prognostic utility in this population of cats. Further studies including the larger population of cats with underlying cardiac or respiratory disease are warranted.

Evaluation of quick sequential organ failure scores in dogs with severe sepsis and septic shock

OBJECTIVES

To evaluate the prognostic utility of the quick sequential organ failure assessment score in dogs with severe sepsis and septic shock presenting to an emergency service, and evaluate the clinical value of the quick sequential organ failure assessment score to predict severe sepsis and septic shock.

MATERIALS AND METHODS

The quick sequential organ failure assessment score was calculated by evaluating respiratory rate (>22 breaths per minute), arterial systolic blood pressure (≤100 mmHg) and altered mentation. The quick sequential organ failure assessment scores with respiratory rate cut-offs of greater than 22, greater than 30 and greater than 40 were compared. Cases were defined as dogs presented to the emergency room and met at least 2 systemic inflammatory response syndrome criteria, had documented infection, and at least one organ dysfunction. A control population of dogs included animals with non-infectious systemic inflammatory response syndrome.

RESULTS

Forty-five dogs with severe sepsis and septic shock and 45 dogs with non-infectious systemic inflammatory response syndrome were included in the final analysis. The quick sequential organ failure assessment provided poor discrimination between survivors and non-survivors for severe sepsis and septic shock (area under receiving operating characteristic curve, 0.51; 95% confidence interval, 0.35 to 0.67). Discrimination remained poor when quick sequential organ failure assessment greater than 30 and quick sequential organ failure assessment greater than 40 scores were calculated (area under receiving operating characteristic curve, 0.56; 95% confidence interval, 0.39 to 0.72, and 0.54; 95% confidence interval, 0.36 to 0.71). The quick sequential organ failure assessment of at least 2, quick sequential organ failure assessment greater than 30 of at least 2 and quick sequential organ failure assessment greater than 40 of at least 2 produced sensitivity and specificity to detect severe sepsis and septic shock of 66.7% and 64.5%, 62.2% and 71.1%, 44.4% and 80%, respectively.

CONCLUSION AND CLINICAL SIGNIFICANCE

Scoring systems utilised in emergency rooms should have high sensitivity to reduce missed sepsis cases and treatment delays. The use of the quick sequential organ failure assessment for severe sepsis and septic shock demonstrated poor mortality prediction and low sensitivity to detect canine patients with severe sepsis and septic shock and should not be used alone when screening for sepsis.

Classification of Septic Shock Phenotypes Based on the Presence of Hypotension and Hyperlactatemia in Cats

Background: Three different phenotypes of septic shock based on changes in blood pressure and lactate are recognized in people. Dysoxic shock, representing the combination of fluid-refractory hypotension and hyperlactatemia, is characterized by greater disease severity and mortality compared to cryptic shock (hyperlactatemia alone) and vasoplegic shock (hypotension with normal blood lactate). Little is known about septic shock and specifically its phenotypes in cats. Objective: To analyze the characteristics and prognostic implications of three septic shock phenotypes in cats with sepsis. Methods: Cats with septic shock were prospectively included. Septic shock was defined by the presence of hypotension (mean blood pressure <60 mmHg) requiring vasopressor support and/or persistent hyperlactatemia (>4 mmol/L) and classified in three subgroups: dysoxic shock, vasoplegic shock and cryptic shock. Clinical and clinicopathological variables including APPLE_fast and APPLE_full scores, occurrence of multi-organ dysfunction syndrome (MODS; presence of at least two dysfunctional organs simultaneously) and outcome were compared among subgroups. Cats with sepsis showing normal blood pressure and lactate concentrations hospitalized during the study period were included as uncomplicated sepsis, and compared to cats with septic shock for selected variables. Length of hospital stay and mortality were evaluated in the whole study population. Odds ratios for mortality were calculated using logistic regression analysis. Significance was set at P < 0.05. Results: The study enrolled 48 cats with uncomplicated sepsis and 37 cats with septic shock (dysoxic shock n = 17; vasoplegic shock n = 11; cryptic shock n = 7). Cats with dysoxic shock had significantly higher APPLE_fast and APPLE_full scores compared to vasoplegic and cryptic shock. Mortality rates were not significantly different among cryptic (57%), dysoxic (65%) and vasoplegic shock (91%), while MODS occurrence was significantly lower in cats with cryptic shock (57%) compared to patients affected by dysoxic (94%) and vasoplegic (100%) shock. Cats with septic shock had higher frequency of MODS and greater mortality rate than cats with uncomplicated sepsis. Conclusion: Despite similar in-hospital mortality, cats with dysoxic and vasoplegic shock are characterized by having higher occurrence of multi- organ dysfunction compared to cats affected by cryptic shock. Results from this study suggest novel means of identifying high-risk subgroups of septic cats.

Validation of a commercial human ELISA to measure hyaluronic acid concentration in feline plasma

Our goal was to validate a human hyaluronic acid (HA) ELISA (Hyaluronic acid plus ELISA; TECOmedical Group) for use in feline plasma. Plasma from 5 healthy cats and 5 critically ill cats was used for validation of the assay. Validation methods performed included intra- and inter-assay variability, spike-and-recovery, and dilutional linearity. All measurements were performed in duplicate. The precision study revealed good intra-assay CV of 7.4-8.9%; inter-assay CV was 3.4-4.2%. Extraction efficiency via spiking tests yielded mean recovery of 89.6%. The assay met criteria for acceptable linearity using 3 serial dilutions. Our results demonstrate that this commercial HA ELISA had acceptable analytical performance using feline plasma and could be a useful tool in the veterinary clinical research setting.

Evaluation of coccygeal and radial artery Doppler blood pressure measurements in sick cats with and without abnormalities in tissue perfusion

OBJECTIVE

To compare systolic blood pressure measured by Doppler (SBP) taken from the coccygeal artery versus common digital branch of the radial artery in cats with normal and poor perfusion parameters.

DESIGN

Prospective, observational study.

SETTING

University Teaching Hospital.

ANIMALS

Eighty-five cats presenting to the emergency service for which prior emergency treatment was not received and a blood pressure was indicated on triage.

INTERVENTIONS

Systolic blood pressure was measured by Doppler using the radial and coccygeal arteries. Cats were categorized as having normal or poor tissue perfusion based on physical examination.

MEASUREMENTS AND MAIN RESULTS

Agreement was poor between coccygeal and radial SBP overall with absolute and relative bias (95% limits of agreement) of 23 (-51 to 96) mm Hg and 16% (-38% to 69%), respectively. In cats with poor perfusion, the agreement was absolute bias = 28 mm Hg and relative bias = 22% and with normal perfusion absolute bias = 22 mm Hg, and relative bias = 12%. The median (interquartile range) coccygeal SBP was significantly different from the radial SBP 141 (50) mm Hg versus 120 (45) mm Hg, P < 0.001. In multivariate linear regression, heart rate was negatively associated with coccygeal SBP (r²  = 0.088, P = 0.049), and pale mucous membrane color (P = 0.034) and poor pulse quality (P = 0.007) were independently associated with lower radial SBP (r²  = 0.18).

CONCLUSIONS

Median coccygeal SBP is significantly greater than radial SBP in sick cats with both normal perfusion and hypoperfusion. Agreement between coccygeal and radial SBP is poor in cats and cannot be used interchangeably. As clinically significant differences exist between sites, the authors recommend obtaining SBP from both sites initially and choosing to monitor and trend changes with the one site that correlates most with physical examination findings.

Retrospective evaluation of the prognostic utility of plasma lactate concentration and serial lactate measurements in dogs and cats presented to the emergency room (January 2012 - December 2016): 4863 cases

OBJECTIVE

To determine the prognostic significance of plasma lactate concentration, plasma lactate clearance, and delta lactate in dogs and cats presented to an emergency room (ER).

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS

A total of 8,321 animals with a plasma lactate concentration measured with 4,863 presenting to the ER and 1,529 dogs and 444 cats having a measurement within 4 hours of admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma lactate concentration of dogs and cats presented to a university teaching hospital was retrospectively evaluated. Of dogs and cats with a plasma lactate concentration measured within 4 hours of admission to the ER, hyperlactatemia was common, and the prevalence of hyperlactatemia for dogs 78% (361/462) and cats 67% (78/116) was highest when evaluated within the first 30 minutes following admission. The distribution of patient's plasma lactate concentration was significantly higher in non-survivors compared to survivors at all time points evaluated (P < 0.001). Both lactate clearance (P = 0.010) and delta lactate (P = 0.013) were significantly different between survivors and nonsurvivors. A delta lactate > 4.5 mmol/L was 100% (95% CI: 95 to 100%) specific for nonsurvival in patients with hyperlactatemia measured within 1 hour of admission to the ER. The most common cause of hyperlactatemia was shock in dogs (24%) and urinary tract diseases in cats (22%). Shock was associated with the highest mortality rate in both dogs (61%) and cats (77%). Hyperlactatemia was significantly associated with increased mortality for dogs with shock (P = 0.001), respiratory diseases (P = 0.022), diabetes mellitus (P = 0.018), and liver dysfunction (P = 0.006).

CONCLUSIONS

Hyperlactatemia was associated with mortality in both dogs and cats when measured at any time point in the 4 hours following admission to the ER. Serial lactate measurement may also be a valuable tool to guide clinical management decisions.

Clinicopathological abnormalities associated with increased animal triage trauma score in cats presenting for vehicular trauma: 75 cases (1998-2009)

OBJECTIVE

To document the clinical and clinicopathological changes in cats presenting with vehicular trauma (VT) and to determine whether the calculated animal trauma triage (ATT) score was associated with any clinicopathological abnormalities.

DESIGN

Retrospective descriptive study conducted between 1998 and 2009.

SETTING

University veterinary teaching hospital.

ANIMALS

Seventy-five client-owned cats that presented for VT to an urban veterinary hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pertinent history, physical examination findings, results of biochemical testing, and outcome were extracted from medical records. ATT score was calculated based on physical examination. Patients were classified as having either a low (<5) ATT (n = 30) or a high (≥5) ATT (n = 45) score. Male cats were overrepresented (60.0%), and a majority of cats had outdoor access (65.3%). Low PCV (P = 0.024), low total plasma protein concentration (P = 0.032), low venous blood pH (P = 0.047), high plasma lactate concentration (P = 0.047), low plasma bicarbonate concentration (P = 0.047), low base excess (P = 0.047), and high plasma glucose concentration (P = 0.047) were associated with higher ATT scores. In addition, low noninvasive blood pressure measurements (P = 0.008) were associated with higher ATT scores.

CONCLUSIONS

There was a significant association between lower PCV, lower total plasma protein concentration, lower venous blood pH, higher plasma lactate concentration, lower plasma bicarbonate concentration, lower base excess, higher whole blood glucose concentration, and lower noninvasive blood pressure and higher ATT scores at presentation in feline patients suffering from VT. Prospective evaluation of these values may prove useful in furthering understanding of the pathophysiology of trauma in cats.

New Tests in Feline Veterinary Medicine: When to Use Them and When to Stick with Tried-and-True Tests

The focus of this article is on how interpretations of laboratory data can utilize both population and individual reference intervals, while making the most of routine testing procedures coupled with some of the newer laboratory tests, which can complement the existing tests in diagnosing disease.

Evaluation of the agreement between a point-of-care lactate meter and a handheld laboratory analyzer in cats treated in emergency practice

OBJECTIVE

The purpose of this study was to determine if there was agreement between a new point-of-care (POC) lactate analyzer and a handheld laboratory analyzer when measuring blood lactate concentration in cats.

DESIGN

Prospective observational study.

SETTING

University veterinary teaching hospital.

ANIMALS

Fifty-four cats that presented to an emergency service.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Lactate concentrations as measured by the handheld laboratory analyzer ranged from 0.3 to 15.4 mmol/L. Agreement analysis of the handheld laboratory analyzer and the POC lactate meter demonstrated a bias, -0.06 and limits of agreement ranging from -0.87 to 0.99 mmol/L. Regression analysis demonstrated a coefficient of determination (R² ) of 0.98.

CONCLUSION

Results of the present study indicate that the POC lactate meter provided results that are in agreement with a handheld laboratory analyzer when measuring lactate in clinically ill patients.

Prognostic indicators in cats with septic peritonitis (2002-2015): 83 cases

OBJECTIVE

To identify physical exam findings, clinicopathological parameters, time to surgery, empirical antimicrobial use, and culture results that could be associated with outcome in cats with septic peritonitis (SP).

DESIGN

Retrospective cohort study of cats from 2002 to 2015.

SETTING

Four university teaching hospitals.

ANIMALS

Eighty-three cats diagnosed with SP by cytology or culture.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Fifty-eight cats survived to discharge (69.9%); 1 cat was euthanized in surgery; 20 were euthanized postoperatively; 4 cats suffered cardiac arrest after surgery. The most common etiology of SP was secondary SP due to gastrointestinal perforation (49.4%), followed by primary SP (22.3%). Mean blood glucose concentration was significantly different between survivors and nonsurvivors (P = 0.006). Cats that received appropriate empirical antibiotic therapy were 4.4 times more likely to survive than cats that did not receive appropriate antibiotics (P = 0.018).

CONCLUSIONS

As previously documented, SP secondary to gastrointestinal leakage was the most common etiology. In this population, cats with a higher blood glucose concentration on presentation had a worse prognosis. Cats that received appropriate empirical antimicrobial therapy were more likely to survive.

Clinicopathologic abnormalities associated with increased animal triage trauma score in cats with bite wound injuries: 43 cases (1998-2009)

OBJECTIVE

To document the clinical and clinicopathologic changes in cats presenting with trauma from bite wounds, identify common abnormalities associated with bite wounds, and to determine whether the calculated animal trauma triage (ATT) score is related to any clinicopathologic abnormalities.

DESIGN

Retrospective descriptive study.

SETTING

University veterinary teaching hospital.

ANIMALS

Forty-three client-owned cats that presented for bite wounds to a large, urban, veterinary hospital between 1998 and 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pertinent history, physical examination findings, results of biochemical testing, and outcome were extracted from medical records. Animal triage trauma score was calculated based on the physical examination at presentation in cats with adequate available information. Patients were classified as having either a low (<5) ATT (n = 20) or a high (≥5) ATT (n = 23) score. Male cats were overrepresented (65.1%), and a majority of cats had outdoor access (53.4%). Low venous blood pH (P = 0.047), high plasma lactate concentration (P = 0.018), and low ionized calcium concentration (P = 0.004) were associated with higher ATT scores.

CONCLUSIONS

There is a significant association between low venous blood pH, high plasma lactate concentration, and low ionized calcium concentration and higher ATT scores at presentation in cats suffering from bite wounds. Early recognition of these abnormalities may help to identify more severely injured patients.

Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia

OBJECTIVE

To review the current literature pertaining to the use of lactate as a prognostic indicator and therapeutic guide, the utility of measuring lactate concentrations in body fluids other than blood or plasma, and the clinical management of hyperlactatemia in dogs, cats, and horses.

DATA SOURCES

Articles were retrieved without date restrictions primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Increased plasma lactate concentrations are associated with increased morbidity and mortality. In populations with high mortality, hyperlactatemia is moderately predictive in identifying nonsurvivors. Importantly, eulactatemia predicts survival better than hyperlactatemia predicts death. Consecutive lactate measurements and calculated relative measures appear to outperform single measurements. The use of lactate as a therapeutic guide has shown promising results in people but is relatively uninvestigated in veterinary species. Increased lactate concentrations in body fluids other than blood should raise the index of suspicion for septic or malignant processes. Management of hyperlactatemia should target the underlying cause.

CONCLUSION

Lactate is a valuable triage and risk stratification tool that can be used to separate patients into higher and lower risk categories. The utility of lactate concentration as a therapeutic target and the measurement of lactate in body fluids shows promise but requires further research.

Effect of Intravenously Administered Crystalloid Solutions on Acid-Base Balance in Domestic Animals

Intravenous fluid therapy can alter plasma acid-base balance. The Stewart approach to acid-base balance is uniquely suited to identify and quantify the effects of the cationic and anionic constituents of crystalloid solutions on plasma pH. The plasma strong ion difference (SID) and weak acid concentrations are similar to those of the administered fluid, more so at higher administration rates and with larger volumes. A crystalloid's in vivo effects on plasma pH are described by 3 general rules: SID > [HCO3-] increases plasma pH (alkalosis); SID < [HCO3-] decreases plasma pH (alkalosis); and SID = [HCO3-] yields no change in plasma pH. The in vitro pH of commercially prepared crystalloid solutions has little to no effect on plasma pH because of their low titratable acidity. Appreciation of IV fluid composition and an understanding of basic physicochemical principles provide therapeutically valuable insights about how and why fluid therapy can produce and correct alterations of plasma acid-base equilibrium. The ideal balanced crystalloid should (1) contain species-specific concentrations of key electrolytes (Na+ , Cl- , K+ , Ca++ , Mg++ ), particularly Na+ and Cl- ; (2) maintain or normalize acid-base balance (provide an appropriate SID); and (3) be isosmotic and isotonic (not induce inappropriate fluid shifts) with normal plasma.

Survival analysis of hypotensive cats admitted to an intensive care unit with or without hyperlactatemia: 39 cases (2005-2011)

OBJECTIVE To examine the association between blood lactate concentration and survival to hospital discharge in critically ill hypotensive cats. DESIGN Retrospective case series. ANIMALS 39 cats admitted to an intensive care unit of a university veterinary hospital between January 2005 and December 2011 for which blood lactate concentration was recorded ≤ 1 hour before or after a Doppler-derived arterial blood pressure measurement ≤ 90 mm Hg (ie, hypotension) was obtained. PROCEDURES Medical records of each cat were reviewed to assess survival to hospital discharge, illness severity, duration of hospitalization, age, body weight, and PCV. Results were compared between hypotensive cats with and without hyperlactatemia (blood lactate concentration ≥ 2.5 mmol/L). RESULTS 6 of 39 (15%) hypotensive cats survived to hospital discharge. Twelve (31%) cats were normolactatemic (blood lactate concentration < 2.5 mmol/L), and 27 (69%) were hyperlactatemic. Hypotensive cats with normolactatemia had a higher blood pressure and higher survival rate than hypotensive cats with hyperlactatemia. Five-day Kaplan-Meier survival rates were 57% for normolactatemic cats and 17% for hyperlactatemic cats. Age, body weight, duration of hospitalization, PCV, and illness severity did not differ significantly between hypotensive cats with and without hyperlactatemia. CONCLUSIONS AND CLINICAL RELEVANCE Hypotensive, normolactatemic cats in an intensive care unit had a significantly greater chance of survival to hospital discharge than their hyperlactatemic counterparts. Blood lactate concentration may be a useful prognostic indicator for this patient population when used in conjunction with other clinical and laboratory findings.