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early goal-directed therapy in critically ill people. 11–14 Shock is commonly encountered in neonatal foals, primarily as a result of sepsis, but therapeutic endpoints in equine medicine are largely reliant on assessment of physical examination

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in American Journal of Veterinary Research

low postnatal viability associated with a decrease in the flow of blood and oxygen to the fetus during birth. 3 This low viability significantly increases the time it requires for a neonatal pig to locate a teat of the dam for the first time and begin

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in American Journal of Veterinary Research

Neonatal foals admitted to emergency veterinary facilities are often hemodynamically compromised and require rapid IV administration of fluids. The distribution of these fluids is affected by the physiologic status of each foal, disease process

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in American Journal of Veterinary Research

Abstract

Objective

To determine normal acid-base status of the CSF and to compare it with changes during acute hypercapnia in equine neonates.

Animals

10 clinically normal foals between 1 and 12 days old.

Procedure

CSF and arterial and venous blood samples were collected every 15 minutes during 45 minutes of normocapnia and 90 minutes of hypercapnia in isoflurane-anesthetized foals. CSF samples were collected via a subarachnoid catheter placed in the atlanto-occipital space.

Results

Comparison of blood and CSF gases during normocapnia indicated that CSF was significantly more acidic than blood. The lower pH was attributable to higher CO2 and lower bicarbonate concentrations than those in blood. During hypercapnia, CSF CO2 increased and pH decreased parallel to changes in blood, but changes were not as great as similar changes in venous blood, indicating that some degree of buffering occurs in the CSF of foals.

Conclusions

Normal CSF acid-base status in equine neonates is similar to that in other domestic species. The blood-brain and blood-CSF interfaces in neonates allow rapid diffusion of CO2, but allow only slow diffusion of bicarbonate. Equine neonates are capable of buffering respiratory-induced acid-base changes in the CSF, but the buffering capacity is less than that of the vascular compartment.

Clinical Relevance

Neonatal foals may develop severe respiratory compromise, resulting in hypoxemia and hypercapnia. Because the ability of the CSF to buffer acid-base changes in neonates is reduced, hypercapnia may contribute to the CNS abnormalities that often develop in sick neonates. Thus, normal blood gas values should be maintained in diseased equine neonates. (Am J Vet Res 1996;57:1483-1487)

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in American Journal of Veterinary Research

Summary

Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.

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in American Journal of Veterinary Research

Summary

Respiratory syncytial virus (rsv) infection causes severe lower respiratory tract disease in infants and calves. Neonatal respiratory tract infection in children often produces persistent changes in lung function. The specific objective of this study was to determine whether neonatal calves have transient or persistent alterations in pulmonary function and airway reactivity following rsv infection. Six 2- to 3-day-old Holstein bull calves were inoculated with 10 ml of bovine respiratory syncytial virus (brsv) inoculum (102.7 to 103.8 cell culture infective doses/ml) intranasally and 10 ml of brsv inoculum (104.8 to 105.9 cell culture infective doses/ml) intratracheally for 4 consecutive days, and 5 other calves were sham-inoculated. Prior to inoculation (day 0) and on days 4, 14, and 30 after the last inoculation, body weight (kg), dynamic compliance (Cdyn), pulmonary resistance (RL), and 2 indices of airway reactivity (effective dose [ed] 65Cdyn and ed 200RL) were measured. Control calves gained weight progressively throughout the study, whereas rsv-inoculated calves failed to gain weight for 14 days, but equaled control calf weight by 30 days after inoculation. The Cdyn of control calves increased significantly by 30 days, but did not in the rsv-infected calves. Pulmonary resistance was increased significantly at 4, 14, and 30 days, but was unaffected by sham inoculation. The ed 65Cdyn and ed 200RL indicated an age-dependent increase in reactivity to histamine and an increase in responsiveness in the infected group beginning at 14 days and persisting until the end of the study. The data indicate that brsv causes airway obstruction and hyperreactivity in neonatal calves, which persists for at least 30 days following viral exposure.

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in American Journal of Veterinary Research

SUMMARY

Intracranial pressure (icp) and cerebral perfusion pressure (cpp) were determined in 8 clinically normal neonatal foals. After the foals oriented themselves and nursed the mares, they were sedated as necessary, and local anesthesia was provided for making the skin incisions. Using a technique similar to that used in human beings, an indwelling subdural catheter was placed to measure icp. Carotid artery catheterization was used to measure arterial blood pressure. Cerebral perfusion pressure was calculated as the difference between mean arterial blood pressure and icp.

Intracranial pressure and cpp readings were taken twice during each 24-hour period, starting at 6 hours of age and continuing through 72 hours of age. Mean (± sd) icp were 5.83 ± 1.82, 8.81 ± 2.06, and 9.55 ± 1.55 mm of Hg (range, 2 to 15 mm of Hg), and mean cpp were 80.19 ± 10.34, 75.30 ± 10.86, and 76.80 ± 12.59 mm of Hg (range, 50 to 109 mm of Hg) for each of the first three 24-hour periods after birth, respectively. All 8 foals had physical and neurologic examinations, csf analysis, and computerized axial tomography evaluations. The foals manifested normal behavior during the interval of measurements, and adverse effects of the procedure were not detected during the monitoring period. Establishment of normal values for icp and cpp are important to clinicians who have the opportunity to apply this technique for monitoring and evaluating neonatal foals with signs of cns dysfunction.

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in American Journal of Veterinary Research

Summary

The cellular response induced in the host animal by endotoxin contributes greatly to the morbidity and mortality of gram-negative infections in bovine neonates. We characterized the temporal sequence, magnitude, and duration of mediator release during endotoxemia and evaluated the effect of endotoxin dose and method of administration. Thromboxane B2 (TxB2), and 6-keto prostaglandin F (PGF) concentrations and tumor necrosis factor (tnf), and interleukin-1β (il-1β) activities were measured in 34 newborn calves given Escherichia coli endotoxin at dosage of 0 (saline solution), 0.2, 2.0, or 20 μg/kg of body weight, either by iv administered bolus or infusion over 50 minutes. In all groups and at each lipopolysaccharide dosage, mediators peaked in this sequence: TxB2 and tnf, followed by PGF, then il-1β. Neither dose nor method of administration affected the sequence of mediator release. The magnitude of eicosanoid reponse to endotoxin was dose-dependent. During induced endotoxemia, duration and/or magnitude of mediator response reflected the dose of endotoxin administered, indicating that the outcome of endotoxemia, in neonatal calves, may be related to the amount of circulating endotoxin.

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in American Journal of Veterinary Research
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Summary

Saline (0.9% NaCl) solution or 1 of 3 nonsteroidal anti-inflammatory drugs (nsaid) was administered iv to 5 neonatal calves 15 minutes after the start of a 3-hour iv infusion of Escherichia coli lipopolysaccharide (lps; 2 µg/kg/h). Four additional calves were given a 3-hour iv infusion of saline solution alone. Clinical attitude, mean arterial blood pressure, pcv, wbc, and plasma lactate, glucose, and eicosanoid concentrations (thromboxane B2, 6-keto-PGF) were monitored for 12 hours.

Flunixin meglumine (1.1 mg/kg of body weight, iv), ketoprofen (2.2 mg/kg, iv), and ketorolac tromethamine (1.1 mg/kg, iv) each ameliorated the clinical signs of endotoxemia and lps-induced lacticemia, but failed to significantly alter the degree of leukopenia or hypoglycemia associated with infusion of lps. Although the 3 nsaid prevented eicosanoid production, they provided only partial protection against lps-induced hypotension. Each nsaid modified the response to lps, but none was clearly superior to the others in modulating the clinical signs or physiologic alterations induced by infusion of lps in neonatal calves.

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in American Journal of Veterinary Research

Summary

Labor and delivery stimulate increased release of catecholamines and endogenous opioid peptides in neonates. Catecholamines promote adaptation to the extrauterine environment after birth. Enkephalins are stored together with catecholamines in the adrenal medulla and have an inhibitory effect on catecholamine release. We investigated the influence of labor and neonatal hypoxia on epinephrine, norepinephrine, and met-enkephalin release in calves. Blood samples were taken from the umbilical artery before rupture of the umbilical cord and from the jugular vein repeatedly after birth. Highest plasma norepinephrine concentration was found in calves delivered at the end of gestation (term calves) before umbilical cord rupture. In calves delivered before the physiologic end of gestation (preterm calves), norepinephrine values increased after cord rupture, but remained lower than values in term calves. Epinephrine release followed a similar pattern, but norepinephrine was clearly predominant. In term calves, met-enkephalin values were significantly higher than values in preterm calves. In calves of both groups, met-enkephalin release increased after cord rupture. During birth, the increase in catecholamine release seems to take place earlier than that of enkephalins. Norepinephrine-dominated stimulation during expulsion of the calf might be followed by increasing enkephalinergic inhibition after cord rupture and onset of respiration. Reduced release of catecholamines and enkephalins in preterm calves may be connected with delayed adaptation to the extrauterine environment.

Free access
in American Journal of Veterinary Research