Comparison of the Accu-Chek Aviva point-of-care glucometer with blood gas and laboratory methods of analysis of glucose measurement in equine emergency patients

Background: More information is needed regarding accuracy of commonly used methods of glucose measurement in the critically ill horse.
Hypothesis: Glucometry will have good agreement with a laboratory standard. Glucometry with plasma will have better agreement than when performed with whole blood.
Animals: Fifty sequentially admitted equine emergency patients, aged >1year.
Methods: Venous blood was collected at admission and immediately analyzed by point-of-care glucometry on both whole blood (POC/WB) and plasma (POC/PL), a multielectrode blood gas analyzer with whole blood (BLG), and a standard laboratory method with plasma (CHEM). Paired data were compared using Lin's concordance correlation, Pearson's correlation, and robust regression. Bias and limits of agreement were tested by the Bland-Altman technique. Bivariate regression analysis was used to explore confounding factors.
Results: Concordance was significant for all comparisons, and was strongest for CHEM-POC/PL (0.977) and weakest for POC/WB-POC/PL (0.668). Pearson's correlation was excellent for all comparisons except those with POC/WB. All comparisons had excellent robust regression coefficients except those with POC/WB.
Conclusions and Clinical Importance: POC glucometry with plasma had excellent agreement with a laboratory standard, as did blood gas analysis. POC glucometry with whole blood correlated poorly with a laboratory standard. These differences may be clinically important, and could affect decisions based on glucose concentrations.     

Blood glucose concentrations in critically ill neonatal foals

Reasons for Performing Study: Critical illness is associated with hyperglycemia in humans, and a greater degree and duration of hyperglycemia is associated with nonsurvival. Hypoglycemia is also seen in critically ill humans, and is associated with nonsurvival. This might also be true in the critically ill foal.
Objectives: To investigate the association of blood glucose concentrations with survival, sepsis, and the systemic inflammatory response syndrome (SIRS).
Methods: Blood glucose concentrations at admission (515 foals) and 24 hours (159 foals), 36 hours (95), 48 hours (82), and 60 hours (45) after admission were analyzed. Logistic regression analyses were performed to investigate the association of glucose concentrations with survival, sepsis, a positive blood culture, or SIRS.
Results: 29.1% of foals had blood glucose concentrations within the reference range (76–131 mg/dL) at admission, 36.5% were hyperglycemic, and 34.4% were hypoglycaemic. Foals that did not survive to hospital discharge had lower mean blood glucose concentrations at admission, as well as higher maximum and lower minimum blood glucose concentrations in the 1st 24 hours of hospitalization, and higher blood glucose at 24 and 36 hours. Foals with blood glucose concentrations <2.8 mmol/L (50 mg/dL) or >10 mmol/L (180 mg/dL) at admission were less likely to survive. Hypoglycemia at admission was associated with sepsis, a positive blood culture, and SIRS.
Conclusions and Potential Relevance: Derangements of blood glucose concentration are common in critically ill foals. Controlling blood glucose concentrations may therefore be beneficial in the critically ill neonatal foal, and this warrants further investigation.     

Measurement of plasma colloid osmotic pressure in neonatal foals under intensive care: comparison of direct and indirect methods and the association of COP with selected clinical and clinicopathologic variables

Objectives: To describe and compare admission colloid osmotic pressure (COP) measurement using both direct and indirect methods in neonatal foals under intensive care, and to evaluate for associations between COP and clinical/clinicopathologic parameters. Design: Prospective study. Setting: Intensive care unit at a veterinary medical teaching hospital. Animals: Twenty‐six critically ill neonatal foals were studied. A control group consisted of 9 clinically healthy neonatal foals. Interventions: Clinicopathologic data were collected at the time of admission. COP was measured directly using a colloid osmometer. Indirect COP was calculated using equations by both Landis–Pappenheimer (L–P) and Thomas and Brown. Measurements and main results: Measured admission COP values were 17.1±4.3 and 17.7±2.4 mmHg in critically ill and control foals, respectively, and these values were not significantly different. Critically ill foals with blood lactate concentrations >3 mmol/L had lower COP values than those with lactate ≤3 mmol/L. There was close agreement between indirect COP values calculated using the L–P equation and direct COP values measured in control foals (mean error=0.0±1.3 mmHg; R²=0.87). However, indirect values were not as predictive of direct COP in critically ill foals (mean error=0.8±3.8 mmHg; R²=0.64). As COP values increased, the indirect method tended to overestimate COP, whereas at lower values it slightly underestimated COP. Conclusion: While the L–P equation was a close approximation of direct COP in healthy foals, direct measurements of oncotic pressure cannot be replaced for monitoring of critically ill foals. Critically ill foals with higher lactate concentrations had lower COP values, suggesting a possible relationship between COP and lactate.     

Insulin, glucagon, and leptin in critically ill foals

Background: Endocrine dysregulation of hormones of energy metabolism is well documented in critically ill humans, but limited information exists in septic foals. The purpose of this study was to provide information on the hormonal response to energy metabolism in critically ill foals, focusing on insulin, glucagon, and leptin. Hypothesis: Concentrations of insulin, glucagon, leptin, and triglycerides will be higher, whereas glucose concentration will be lower in septic foals than in healthy and sick nonseptic foals. The magnitude of these differences will be associated with severity of disease and nonsurvival. Animals: Forty‐four septic, 62 sick nonseptic, and 19 healthy foals <7 days of age. Methods: In this prospective multicenter cross‐sectional study, blood samples were collected at admission. Foals with positive blood culture or sepsis score ≥12 were considered septic. Results: Septic foals had lower glucose and insulin and higher triglyceride and glucagon concentrations than did healthy foals. Glucagon concentrations were not different between septic foals that died (n = 14) or survived (n = 30). Higher insulin and lower leptin concentrations were associated with mortality. Quantitative insulin‐sensitivity check index was higher in septic foals. Conclusions and Clinical Importance: Energy metabolism and the endocrine response of related hormones in septic foals are characterized by hypoglycemia, hypertriglyceridemia, low insulin concentration, and high glucagon concentration. Leptin and insulin may have prognostic value for nonsurvival in septic foals. The hormonal response related to energy metabolism in critical illness differs between foals and humans.     

Indirect oscillometric and direct blood pressure measurements in anesthetized and conscious neonatal foals

Objective: To investigate the agreement between indirect oscillometric and direct blood pressure measurement in the equine neonate. Design: Prospective observational study. Setting: University Veterinary Teaching Hospital. Animals: Ten crossbred foals of 30–46 hours of age. Interventions: Six animals (Group 1) were anesthetized. Four animals (Group 2) were restrained on a mat. All animals were instrumented with a catheter in the greater metatarsal artery and an oscillometric blood pressure cuff over the coccygeal artery. Blood pressure was varied with dobutamine, phenylephrine, nitroprusside, and increased depth of anesthesia (Group 1) or dopamine (Group 2). Measurements and main results: Simultaneous direct and indirect blood pressure measurements were obtained from the greater metatarsal artery and the coccygeal artery, respectively. There was good agreement between the 2 methods for mean and diastolic blood pressures in both groups, but not for systolic pressure. The agreement was best in mean blood pressure of anesthetized foals (mean bias –1.07; limits of agreement – 9.39, 7.25 mmHg). Conclusions: Indirect oscillometry appears to be an acceptable method for measuring mean arterial blood pressure in both anesthetized and conscious neonatal foals, and may be a valid method of monitoring critically ill foals.     

Evaluation of a Veterinary Glucometer for Use in Horses

Background: Glucose assessment and regulation are important factors in the treatment of hospitalized horses and foals. Hypothesis/Objectives: The purpose of this study was to compare glucose measurement by a veterinary glucometer, adjusted by code for use in horses and foals, to a reference chemistry analyzer. It was hypothesized that the veterinary glucometer and reference analyzer would yield similar results and that interpretation of glucose values obtained from a veterinary glucometer would result in clinically appropriate decisions. Animals: Fifty blood samples from adult horses and 50 blood samples from neonatal foals admitted to the Colorado State University Veterinary Hospital or Equine Reproduction Laboratory for evaluation. Methods: Glucose concentrations from fresh whole blood samples were evaluated in duplicate with a veterinary glucometer and these values were compared with those obtained with a reference plasma chemistry analyzer. The accuracy of glucometer measurement was evaluated with a Clarke error grid. Results: The veterinary glucometer accurately measured whole blood glucose concentrations in both horses and foals when compared with a reference plasma chemistry analyzer. Nearly 97% of the glucometer values obtained in this study would have resulted in appropriate clinical decisions based on the Clarke error grid analysis. Conclusions and Clinical Importance: The veterinary glucometer evaluated has potential utility for point‐of‐care whole blood glucose evaluation in both horses and foals.     

Preliminary Investigation of the Area Under the l‐Lactate Concentration–Time Curve (LACAREA) in Critically Ill Equine Neonates

Background

A variety of measures of l‐lactate concentration ([LAC]) in the blood of critically ill neonatal foals have shown utility as prognostic indicators. These measures, evaluating either the severity of hyperlactatemia or the duration of exposure to hyperlactatemia, perform fairly well and have correctly classified 75–80% of foals examined in several studies. The area under the l‐lactate concentration versus time curve (LAC _Area) encompasses both severity and duration of hyperlactatemia and should improve correct classification of patient survival.

Hypothesis/Objectives

LAC _Area is larger in nonsurviving critically ill neonatal foals.

Animals

Forty‐nine foals admitted for critical illness to 1 of 4 referral hospitals.

Methods

Whole blood was obtained at admission and 6, 12, 18, and 24 hours after admission for measurement of l‐lactate using a handheld lactate meter. LAC _Area was calculated for: admission–6, 6–12, 12–18, 18–24 hours, and admission–24 hours using the trapezoidal method and summing the 6‐hours interval areas to determine total 24 hours area. Differences between survivors and nonsurvivors were determined using robust regression and Kruskal–Wallis testing, P < .05.

Results

LAC _Area was significantly larger in nonsurviving foals (n = 9) than in surviving foals (n = 40) at all time periods examined.

Conclusions and Clinical Importance

Differences in LAC _Area between surviving and nonsurviving critically ill neonatal foals are large and support further investigation of this method as an improved biomarker for survival in critically ill neonatal foals is indicated.     

Bacterial isolates from blood and their susceptibility patterns in critically ill foals: 543 cases (1991-1998)

OBJECTIVE: To assess microorganisms isolated from blood specimens obtained from critically ill neonatal foals and to evaluate their antimicrobial susceptibility patterns. DESIGN: Retrospective study. ANIMALS: 543 neonatal foals. PROCEDURE: Medical records of foals that were < 1 month old and were admitted to a referral neonatal intensive care unit were reviewed for results of bacteriologic culture of blood and antimicrobial susceptibility patterns. RESULTS: At least 1 microorganism was isolated from 155 of 543 (28.5%) foals. Escherichia coli was the most commonly isolated bacterium. A single gram-positive organism was detected in 49 foals. Although 90% of the E coli isolates were susceptible to amikacin, some gram-negative and gram-positive organisms had resistance against multiple antimicrobials. CONCLUSIONS AND CLINICAL RELEVANCE: Gram-negative bacteria remain the most common isolates from blood of neonatal foals; however, gram-positive organisms were also found, and with greater prevalence than reported elsewhere. Susceptibility patterns may vary, and resistance to multiple antimicrobials may develop. This is especially true for organisms such as Enterobacter spp and Enterococcus spp. Prudent empirical treatment for neonatal sepsis should include broad-spectrum antimicrobials.     

Serum free cortisol fraction in healthy and septic neonatal foals

Background: Relative cortisol insufficiency occurs in septic foals and impacts survival. Serum free (biologically available) cortisol concentration might be a better indicator of physiologic cortisol status than serum total cortisol concentration in foals. Hypotheses: In septic foals, (1) low free cortisol concentration correlates with disease severity and survival and (2) predicts disease severity and outcome better than total cortisol concentration. Animals: Fifty‐one septic foals; 11 healthy foals; 6 healthy horses. Methods: In this prospective clinical study, foals meeting criteria for sepsis at admission were enrolled. University‐owned animals served as healthy controls. Basal and cosyntropin‐stimulated total cortisol concentration and percent free cortisol (% free cortisol) were determined by chemiluminescent immunoassay and ultrafiltration/ligand‐binding methods, respectively. Group data were compared by ANOVA, Mann‐Whitney U‐tests, and receiver operator characteristic curves. Significance was set at P < .05. Results: Basal % free cortisol was highest in healthy foals at birth (58±8% mean±SD), and was higher (P≤.004) in healthy foals of all ages (33±6 to 58±8%) than in adult horses (7±3%). Cosyntropin‐stimulated total and free cortisol concentrations were lower (P≤.03) in foals with shock (total = 6.2±8.1 μg/dL; free = 3.5±4.8 μg/dL versus total = 10.8±6.0 μg/dL; free = 6.9±3.3 μg/dL in foals without shock) and in nonsurvivors (total = 3.8±6.9 μg/dL; free = 1.9±3.9 μg/dL versus total = 9.1±7.7 μg/dL; free = 5.5±4.4 μg/dL in survivors). Free cortisol was no better than total cortisol at predicting disease severity or outcome in septic foals. Conclusions and Clinical Importance: Serum free cortisol is impacted by age and illness in the horse. There is no advantage to measuring free over total cortisol in septic foals.     

A comparison of noninvasive cardiac output measurement by partial carbon dioxide rebreathing with the lithium dilution technique in anesthetized foals

Newer techniques for cardiac output (Q) determinations that are minimally invasive remain to be validated in neonatal foals against other accepted techniques such as the lithium technique (LiDCO). This study compares Q determinations using the partial CO₂ rebreathing technique (NICO) with LiDCO in anesthetized neonatal foals. Ten foals were instrumented for NICO and LiDCO determinations. For each foal low, intermediate and high levels of cardiac output were achieved in that order using an end‐tidal isoflurane (ETI) concentration of 1.3 – 2.1% for the lowest rate; an ETI of 0.85–1.4% and a constant‐rate infusion of dobutamine (1–3 ?g/kg/min) for the intermediate rate; and an ETI of 0.83–1% and dobutamine (2–6 ?g/kg/min) for the highest rate. Four foals also received IV intermittent doses (total cumulative dose of 1.1–1.7 mg) of phenylephrine at the highest rate of Q. The measurements were obtained in duplicate or triplicate for each Q technique after achieving a stable hemodynamic plane for at least 15 minutes at each rate of Q. For the lithium technique, all foals received 1.1–1.9 mL (0.16–0.28 mmol) of lithium. A Bland‐Altman analysis was used to compare the bias and precision of the two techniques. Eighty seven comparisons were determined between the two techniques. Eight were excluded due to more than 20% variation between the LiDCO determinations or technical errors at the time of determination. The correlation coefficient between the two methods was 0.67 for all Q determinations. Mean LiDCO and NICO values from 79 measurements were 130 ± 40 mL^–1 kg minute^–1 (range, 68– 237) and 152 ± 31 mL^–1 kg minute^–1 (89 – 209), respectively. The mean ( mL^–1 kg minute^–1) of the differences of LiDCO – NICO was = –0.7248 + 0.8602 NICO. The precision (1.96 SD) of the differences between LiDCO and NICO was 58.9 mL^–1 kg minute^–1 (–80.9–+36.9) with a mean difference of –22 mL^–1 kg minute^–1 (bias; 95% CI – 15.2 to ‐28.7). In conclusion, given the small bias compared to the limits of agreement, the NICO technique for determining Q deserves further consideration for adoption into clinical practice in neonatal foals.     

Intragastric pH in critically ill neonatal foals and the effect of ranitidine

OBJECTIVE: To characterize intragastric pH profiles in critically ill foals and determine whether administration of ranitidine altered pH profiles. DESIGN: Prospective observational study. ANIMALS: 23 hospitalized neonatal foals < or = 4 days of age. PROCEDURE: Intragastric pH was measured continuously for up to 24 hours by use of an indwelling electrode and continuous data recording system. In 21 foals, ranitidine was administered IV. RESULTS: 10 foals had predominantly or exclusively alkaline profiles, 10 had profiles typical of those reported for healthy foals, with periods of acidity (hourly mean pH < 5.0 at least once), and 3 had atypical profiles with periods of acidity. All 10 foals that had intragastric pH profiles typical of healthy foals survived, whereas only 2 foals with alkaline profiles survived, and none of the foals with atypical profiles survived. The effects of ranitidine administration could not be assessed in 13 foals because of a high baseline intragastric pH. In 7 of the remaining 9, ranitidine administration resulted in an alkalinizing response, but this response was often of blunted duration. Ranitidine administration did not appear to alter the intragastric pH profile in the remaining 2 foals. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that hospitalized critically ill foals often have intragastric pH profiles different from those reported for healthy foals and may respond differently to ranitidine administration than do healthy foals. Many critically ill foals have continuously alkaline intragastric pH profiles, questioning the need for prophylactic administration of ranitidine in all critically ill foals.     

Association of hyperlactatemia with age,diagnosis, and survival in equine neonates

Objective – To investigate the association between blood lactate concentration, measured at admission and following 12–36 hours of treatment, and age, diagnosis, and survival in neonatal foals. Design – Retrospective, observational study. Setting – Two equine referral hospitals. Animals – One hundred and twelve foals ≤96 hours of age were included. Interventions – Arterial or venous blood samples were obtained from all foals at admission and surviving foals at 12–36 hours. Measurements – The lactate concentration (LAC) was recorded at 2 time points: admission (LAC‐Admission) and 12–36 hours following treatment (LAC‐24 hours). Main Results – LAC decreased by 0.05 mmol/L for each increased hour of age at presentation. Premature/dysmature foals demonstrated increased odds of nonsurvival of 55% for each 1 mmol/L increase in LAC‐Admission while foals with major diagnoses of neonatal encephalopathy (NE), enteritis and ‘Other’ had increased odds of nonsurvival of 52%, 113%, and 247%, respectively, for each 1.0 mmol/L increase in LAC. Blood‐culture positive foals had significantly lower LAC than blood culture negative foals. LAC‐Admission and LAC‐24 hours were significantly larger in nonsurviving foals. LAC‐Admission of >6.9 mmol/L and LAC‐24 hours >3.2 mmol/L, respectively, correctly classified 85.6% and 94.1% of cases as survivors or nonsurvivors. No differences were found when the 24‐hour change in LAC was investigated in terms of outcome, age at admission, or major diagnosis; however, LAC‐24 hours remained significantly associated with survival. Conclusions – Admission or persistent hyperlactatemia is associated with a nonsurvival. Younger foals, premature/dysmature foals, and foals with neonatal encephalopathy had the largest LAC.     

Comparison of a portable blood glucose meter analyzer with a benchtop point-of-care chemistry analyzer for measurement of blood glucose concentration in client-owned ferrets (Mustela putorius furo)

BackgroundHypoglycemia is common in pet ferrets (Mustela putorius furo) because of the high prevalence of insulinoma in this species. The objectives of this study were to evaluate agreement of a portable blood glucose meter (PBGM) with a benchtop point-of-care (POC) chemistry analyzer for measurement of blood glucose concentration in ferrets, and to assess the clinical impact of using a PBGM for blood glucose measurement. The benchtop POC analyzer was used as the reference analyzer (modified hexokinase method).MethodsGlucose concentration was measured from 82 blood samples from client-owned ferrets with the benchtop POC chemistry analyzer and the PBGM. Agreement and bias between measurements were assessed using the Bland-Altman method and a Passing-Bablok regression analysis. A modified Clarke error grid analysis was modelized to evaluate the clinical effect if the PBGM was used rather than the benchtop POC chemistry analyzer.ResultsGlucose values obtained with the PBGM were not in agreement with the benchtop POC chemistry analyzer, and it underestimated blood glucose concentration in many cases. However, variation was unpredictable (mean bias, -3.97 mg/dL; range, -52.2 to 64.8 mg/dL), with wide 95% LOA (-47.3 to 38.5 mg/dL). A Passing-Bablok linear regression analysis had a slope of 1.13 (95% confidence interval: 1.00–1.36), and an intercept of -20.78 (95% confidence interval: -38.92 to -9.90), highlighting presence of a proportional and a constant bias. Important clinical error would have occurred in 1% of cases with the PBGM.ConclusionUnpredictable variation of glucose results obtained with the PBGM could have an important impact on clinical decision making. Thus, the use of a benchtop POC analyzer using hexokinase method for measurement of blood glucose concentration should be favored in ferrets for rapid onsite result obtention.     

Evaluation of a point‐of‐care blood glucose monitor in healthy goats

Objective

To assess agreement between a point‐of‐care glucometer (POCG) and a laboratory chemistry analyzer for blood glucose measurements in goats.

Design

Prospective study.

Setting

University teaching hospital.

Animals

Eighteen healthy adult goats.

Investigations

Whole blood samples were obtained via jugular venipuncture prior to premedication with xylazine and butorphanol (T0), following premedication (T20), and after 1 hour of inhalant anesthesia (T60). Each sample was tested with a POCG and a laboratory analyzer (HITA). Agreement was assessed using concordance correlation coefficients and calculation of bias and 95% limits of agreement.

Measurements and Main Results

Mean blood glucose concentration at T0 was 3.9 ± 0.6 mmol/L (70 ± 10 mg/dL; POCG) and 2.9 ± 0.4 mmol/dL (53 ± 8 mg/dL; HITA). Glucose concentrations at T20 were 6.7 ± 2.4 mmol/L (121 ± 43 mg/dL) and 5.4 ± 2.1 mmol/L (97 ± 37 mg/dL) and at T60 were 5.7 ± 1.7 mmol/L (102 ± 31 mg/dL) and 4.7 ± 1.3 mmol/L (85 ± 24 mg/dL) when measured with the POCG and HITA, respectively. The POCG overestimated blood glucose compared to the HITA. The bias ± SD was 1.08 ± 0.53 mmol/L (19.4 ± 9.5 mg/dL) (95% LOA 0.04 to 2.11 mmol/L [0.7 to 38.0 mg/dL]) and the concordance correlation coefficient was 0.82. After correcting the results of the POCG using a mixed‐effects linear model, the bias was 0.0 ± 0.38 mmol/L (0.0 ± 6.8 mg/dL) (95% LOA ± 0.74 mmol/L [± 13.4 mg/dL]) and the concordance correlation coefficient was 0.98.

Conclusions

The POCG overestimated blood glucose concentrations in goats, compared to the HITA, but when the POCG concentrations were corrected, the agreement was excellent.     

Parenteral nutrition in neonatal foals: clinical description, complications and outcome in 53 foals (1995-2005)

This retrospective study describes the use of and complications associated with parenteral nutrition (PN) administration to 53 equine neonates at the University of California Veterinary Medical Teaching Hospital. Medical records were examined and information obtained on signalment, physical examination, clinical diagnosis, outcome, total hospitalization time, insulin administration, microbiology culture results, other complications (i.e. thrombophlebitis) and necropsy findings. Complete blood count and serum biochemistry analytes, venous blood gas, serum electrolyte and glucose concentrations, and blood lactate concentration results were compared before and during PN administration in all foals. Seventeen foals (32%) developed hypertriglyceridemia (>200mg/dL). Triglyceride concentrations >200mg/dL were significantly (P=0.049) associated with non-survival. Forty-seven foals (89%) developed hyperglycemia (blood glucose >120mg/dL) and eight (15%) developed catheter-related complications (thrombosis or local sepsis). Packed cell volume, total protein, creatinine, blood urea nitrogen, and sorbitol dehydrogenase concentrations decreased while foals were on PN, while serum chloride concentration increased. This study highlighted that hypertriglyceridemia during the acute phase of neonatal illness may be detrimental to outcome, and that the safety of lipid-containing solutions in foals warrants further study.     

Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Hospitalized Neonatal Foals

Background: Transient hypothalamic-pituitary-adrenal (HPA) axis dysfunction occurs frequently in critically ill humans and impacts survival. The prevalence and impact of HPA axis dysfunction in critically ill neonatal foals are not well characterized.
Hypotheses: (1) HPA axis dysfunction occurs in hospitalized neonatal foals, and is characterized by inappropriately low basal serum cortisol concentration or inadequate cortisol response to exogenous adrenocorticotropic hormone (ACTH); (2) hospitalized foals with HPA axis dysfunction have more severe disease and are less likely to survive than hospitalized foals with normal HPA axis function.
Animals: Seventy-two hospitalized foals and 23 healthy age-matched foals.
Methods: Basal ACTH and cortisol concentrations were measured and a paired low-dose (10 μg)/high-dose (100 μg) cosyntropin stimulation test was performed at admission in hospitalized foals. HPA axis dysfunction was defined as (1) an inappropriately low basal cortisol concentration or (2) an inadequate increase in cortisol concentration (delta cortisol) after administration of cosyntropin, with cut-off values for appropriate basal and delta cortisol concentrations determined from results obtained in healthy age-matched foals.
Results: Forty-six percent of hospitalized foals had an inappropriately low basal cortisol concentration and 52% had an inadequate delta cortisol concentration after administration of the 100 μg dose of cosyntropin. An inadequate delta cortisol response to the high (100 μg) dose of cosyntropin was significantly correlated with shock and multiple organ dysfunction syndrome in hospitalized foals, and with decreased survival in a subgroup of septic foals.
Conclusions and Clinical Importance: HPA axis dysfunction occurs frequently in hospitalized neonatal foals, and negatively impacts disease severity and survival.     

Yeast Flora in Oropharyngeal and Rectal Mucous Membranes of Healthy and Critically Ill Neonatal Foals

Little is known about the normal or pathologic yeast flora in healthy and critically ill neonatal foals. The aims of this study were to evaluate the yeast flora colonizing the mucous membranes of the digestive tract (oropharynx and rectum mucous membranes) of healthy and hospitalized foals and to find out risk factors involved in yeast colonization of foals referred to a neonatal intensive care unit. A total of 240 swabs were collected from 21 healthy (group A) and 39 sick (group B) foals. In 14 of the 60 foals, yeast was isolated in at least one sample (23.3%): 3 of the 21 foals (14.3%) were positive in group A and 11 of 39 foals (28.2%) were positive in group B. The yeasts were isolated from rectal swabs obtained from none in healthy foals, whereas 5 of the 39 sick foals were positive; however, this difference was not statistically significant. No significant difference was also detected regarding oropharyngeal swabs between healthy (3/21) and sick (10/39) foals. The risk factors significantly associated with the isolation of yeasts from rectal swabs were female sex, treatment with oral antibiotics, and stressful diagnostic–therapeutic procedures. The only risk factor significantly associated with the isolation of yeast from oropharyngeal swabs was the treatment with antacids and gastroprotectants. The results show that fungi present in the gastrointestinal tract of neonatal foals were mainly environmental yeasts and suggested the absence of a stable fungal colonization. Candida was the genus frequently isolated in hospitalized foals, just as it is isolated in critically ill human neonates.     

Pharmacokinetics of butorphanol and evaluation of physiologic and behavioral effects after intravenous and intramuscular administration to neonatal foals

Background: Despite frequent clinical use, information about the pharmacokinetics (PK), clinical effects, and safety of butorphanol in foals is not available. Objectives: The purpose of this study was to determine the PK of butorphanol in neonatal foals after IV and IM administration; to determine whether administration of butorphanol results in physiologic or behavioral changes in neonatal foals; and to describe adverse effects associated with its use in neonatal foals. Animals: Six healthy mixed breed pony foals between 3 and 12 days of age were used. Methods: In a 3‐way crossover design, foals received butorphanol (IV and IM, at 0.05 mg/kg) and IV saline (control group). Butorphanol concentrations were determined by high‐performance liquid chromatography and analyzed using a noncompartmental PK model. Physiologic data were obtained at specified intervals after drug administration. Pedometers were used to evaluate locomotor activity. Behavioral data were obtained using a 2‐hour real‐time video recording. Results: The terminal half‐life of butorphanol was 2.1 hours and C₀ was 33.2 ± 12.1 ng/mL after IV injection. For IM injection, C_max and T_max were 20.1 ± 3.5 ng/mL and 5.9 ± 2.1 minutes, respectively. Bioavailability was 66.1 ± 11.9%. There were minimal effects on vital signs. Foals that received butorphanol spent significantly more time nursing than control foals and appeared sedated. Conclusions and Clinical Importance: The disposition of butorphanol in neonatal foals differs from that in adult horses. The main behavioral effects after butorphanol administration to neonatal foals were sedation and increased feeding behavior.     

Mucosal mRNA Cytokines’ Profile of Gastric Wall in Neonatal Foals: Comparison with Endoscopy and Histology

Gastritis and gastric ulcerations occur frequently in neonatal foals. The relationship between cytokines expressed by gastric mucosa and gastric histopathology in healthy or sick foals has never been investigated. The aim of this study was to compare the histological diagnosis and endoscopic view with cytokine expression (TNF-α, IL-1β, IL-4, IL-8, IL-13, and IFN-γ) of gastric mucosa. Twenty-two foals were definitively enrolled in the study: 19 were critically ill, and 3 were healthy foals. Gastric biopsy specimens were collected for histological examination and for cytokine mRNA qualitative real-time PCR analysis. This study shows that there is a substantial agreement between histology and endoscopy and that foals with evidence of gastritis and gastric ulcerations have higher probability of expressing TNF-α. Moreover, the overall profile of cytokines expression, with a low percentage of IFN-γ, a high percentage of IL-4, and the absence of IL-13, suggests a down-regulation of the Th1 cell-mediated immune response and an impaired Th2 response in the gastric wall in the neonatal period.     

Serum lactoferrin and immunoglobulin G concentrations in healthy or ill neonatal foals and healthy adult horses

BACKGROUND: Lactoferrin is a colostral glycoprotein with antimicrobial properties. HYPOTHESES: (1) Serum lactoferrin and immunoglobulin G (IgG) concentrations are correlated and increase in healthy foals after ingestion of colostrum; (2) compared to healthy foals, ill foals will have lower lactoferrin concentrations that correlate with their IgG concentration, neutrophil count, the diagnosis of sepsis, and survival; and (3) plasma concentrations of lactoferrin will be less than serum concentrations. ANIMALS: Healthy foals (n = 16), mature horses (n = 10), and ill foals 1-4 days old (n = 111) that were examined for suspected sepsis were used for blood collection. Colostrum was obtained from 10 healthy mares unrelated to the foals. METHODS: Blood was obtained from the healthy foals at birth and 1-3 days of age and from the ill foals at admission. Serum IgG was quantified by single radial immunodiffusion (SRID). Lactoferrin concentrations in colostrum and blood were determined by an enzyme-linked immunosorbant assay. The sepsis score, blood culture results, neutrophil counts, and survival were obtained on ill foals. RESULTS: The mean colostral lactoferrin concentration was 21.7 microg/mL. Compared to values at birth, serum IgG (18+/-2 versus 2,921+/-245 mg/dL, SEM) and lactoferrin (249+/-39 versus 445+/-63 ng/mL, SEM) concentrations were significantly greater in healthy foals 1-3 days old. Serum lactoferrin concentration in 1-3-day-old healthy foals was not different from mature horses or ill foals. IgG and lactoferrin concentrations were significantly correlated only in healthy foals. Serum lactoferrin concentrations were significantly lower in ill neutropenic foals. The serum IgG concentration was significantly lower in ill foals as compared to healthy foals. Only serum IgG was significantly less in ill foals with a positive sepsis score and in nonsurvivors, Plasma lactoferrin concentrations were lower than serum concentrations, although values were significantly correlated. CLINICAL IMPORTANCE: Although both serum IgG and lactoferrin concentrations increase in healthy foals after ingestion of colostrum, only serum IgG is significantly correlated with the sepsis score and outcome.