E P Steffey's research while affiliated with University of California and other places
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Publications (220)
Although morphine has demonstrated antinociceptive effects in horses, its administration has been associated with dose-dependent adverse effects. In humans and rats, part of the analgesic effect of morphine has been attributed to the active metabolite, morphine-6-glucuronide (M6G). Although morphine can cause several undesirable effects, M6G has a...
Objective
To evaluate the effects of combined infusions of vatinoxan and dexmedetomidine on inhalant anesthetic requirement and cardiopulmonary function in dogs.
Study design
Prospective experimental study.
Methods
A total of six Beagle dogs were anesthetized to determine sevoflurane minimum alveolar concentration (MAC) prior to and after an intr...
Background:
Meperidine is a synthetic opioid that belongs to the phenylpiperidine class and is a weak mu receptor agonist. In horses there are a limited number of published studies describing the analgesic effects of systemically administered meperidine in horses. The objective of this study was to describe the pharmacokinetics, behavioral and phy...
Although controversial, due to its reported effectiveness in attenuating bleeding associated with exercise-induced pulmonary hemorrhage (EIPH), furosemide is currently a permitted race day medication in most North American racing jurisdictions. The objective of this study was to assess the efficacy of furosemide in reducing the presence and severit...
The objective of the current study was to describe and characterize the pharmacokinetics and selected pharmacodynamic effects of morphine and its two major metabolites in horses following several doses of morphine. A total of ten horses were administered a single intravenous dose of morphine: 0.05, 0.1, 0.2, or 0.5 mg/kg, or saline control. Blood s...
Objective
To understand the pharmacokinetics of morphine and correlate the serum values of morphine and its metabolites to pharmacodynamic data.
Materials and Methods
Using a balanced randomized 5‐way crossover design; ten horses received an intravenous injection of saline and morphine at doses of 0.05 mg/kg, 0.1 mg/kg, 0.2 mg/kg, and 0.5 mg/kg. T...
OBJECTIVE To measure concentrations of trazodone and its major metabolite in plasma and urine after administration to healthy horses and concurrently assess selected physiologic and behavioral effects of the drug.
ANIMALS 11 Thoroughbred horses enrolled in a fitness training program.
PROCEDURES In a pilot investigation, 4 horses received trazodone...
Inhalation anesthetics are used widely for the anesthetic management of animals. They are unique among the anesthetic drugs because they are administered, and in large part removed from the body, via the lungs. The chemical structure of inhalation anesthetics and their physical properties determine their actions and safety of administration. The ai...
Objective:
To determine the effects of low and high dose infusions of dexmedetomidine and a peripheral α2-adrenoceptor antagonist, MK-467, on sevoflurane minimum alveolar concentration (MAC) in dogs.
Study design:
Crossover experimental study.
Animals:
Six healthy, adult Beagle dogs weighing 12.6±0.9 kg (mean±standard deviation).
Methods:
Do...
Background:
The effects of anesthesia on the equine electroencephalogram (EEG) after administration of various drugs for sedation, induction, and maintenance are known, but not that the effect of inhaled anesthetics alone for EEG recording.
Objective:
To determine the effects of isoflurane and halothane, administered as single agents at multiple...
Uterine vascular elastosis in mares is characterized by degeneration of uterine vasculature through thickening of the elastin layers. Factors commonly associated with this degeneration include age, parity, and chronic uterine endometritis. Affected mares have also been shown to exhibit decreases in uterine blood flow and perfusion of the uterus. Du...
Background
Previous study of the diagnostic validity of electroencephalography (EEG) to detect abnormalities in equine cerebral cortical function relied on the administration of various drugs for sedation, induction, and maintenance of general anesthesia but used identical criteria to interpret recordings.Objectives
To determine the effects of 2 in...
In the uterus of the mare, data obtained using transrectal Doppler ultrasonography indicate that uterine blood flow (UBF) is dynamic and changes throughout the estrous cycle. Degenerative lesions in the uterus are associated with subfertility and infertility. Among these lesions, vascular elastosis has been reported in aged, multiparous, and infert...
Reason for Performing StudyTramadol is an analgesic agent used in humans and a number of veterinary species. The pharmacokinetics and behavioural effects of tramadol and its active metabolite have been described in adult horses, but not in young foals.Objectives
To characterise the pharmacokinetics, metabolism and some induced behavioural and physi...
Reason for performing studyFoal response to a broader range of plasma fentanyl concentrations than currently reported are desirable to support (or not) clinical use.Objectives
Describe fentanyl plasma concentrations following an escalating i.v. fentanyl dosing schedule in foals of (5-13 days of age) and describe selected, associated dose- and time-...
Reason for Performing StudyThe use of fentanyl is limited in adult horses in part due to potential for central nervous system excitation. The pharmacokinetics and the plasma concentration related behavioural actions of fentanyl are not described for young foals. Objectives
The goal of the current study was to describe the pharmacokinetics and behav...
The objective of the current study was to describe the pharmacokinetics of morphine and its metabolites following intravenous administration to the horse. A total of eight horses (two per dose group) received a single intravenous dose of 0.05, 0.1, 0.2, or 0.5 mg/kg morphine. Blood samples were collected up to 72 h postdrug administration, analyzed...
This study investigated the antinociceptive effects of a constant rate infusion (CRI) of lidocaine during xylazine and ketamine anesthesia in horses and aimed to correlate these effects with cardiorespiratory variables, bispectral index (BIS) and plasma lidocaine concentrations. Six adult crossbred mares weighing 320--400 kg were anesthetized on th...
The history of veterinary anesthesia has paralleled but lagged behind that of anesthesia for human patients (Fig. 23.7). The two have been intimately intertwined, each contributing to the advancement of the other. The introduction of veterinary anesthesia was delayed by the misperception that the induction of anesthesia in animals was painful'and u...
Objective To describe selected pharmacodynamic effects of detomidine and yohimbine when administered alone and in sequence.
Study design Randomized crossover design.
Animals Nine healthy adult horses aged 9 ± 4 years and weighing 561 ± 56 kg.
Methods Three dose regimens were employed in the current study. 1) 0.03 mg kg−1 detomidine IV, 2) 0.2 mg kg...
Both the potential analgesic effect and the conflicting reports describing tramadol disposition in the horse warrant further study of the pharmacokinetics of tramadol in this species.
To describe the pharmacokinetics of tramadol and its metabolites, O-desmethyltramadol and N-desmethyltramadol, following i.v. administration of 3 doses to the horse....
To test the hypothesis that hypercapnic hyperpnea produced using endotracheal insufflation with 5-10% CO(2) in oxygen could be used to shorten anesthetic recovery time in horses, and that recovery from sevoflurane would be faster than from isoflurane.
Randomized crossover study design.
Eight healthy adult horses.
After 2 hours' administration of co...
The administration of certain sedatives has been shown to promote sleep in humans. Related agents induce sleep-like behavior when administered to horses. Interpretation of electroencephalograms (EEGs) obtained from sedated horses should take into account background activity, presence of sleep-related EEG events, and the animal's behavior.
Sedatives...
To describe the pharmacokinetics of detomidine and yohimbine when administered in combination.
Randomized crossover design.
Nine healthy adult horses aged 9 ± 4 years and weighing of 561 ± 56 kg.
Three dose regimens were employed in the current study. 1) 0.03 mg kg(-1) detomidine IV (D), 2) 0.2 mg kg(-1) yohimbine IV (Y) and 3) 0.03 mg kg(-1) detom...
To determine whether infusion of xylazine and ketamine or xylazine and propofol after sevoflurane administration in horses would improve the quality of recovery from anesthesia.
6 healthy adult horses.
For each horse, anesthesia was induced by administration of xylazine, diazepam, and ketamine and maintained with sevoflurane for approximately 90 mi...
To determine the anesthetic-sparing effect of maropitant, a neurokinin 1 receptor antagonist, during noxious visceral stimulation of the ovary and ovarian ligament in dogs.
Eight 1-year-old female dogs.
Dogs were anesthetized with sevoflurane. Following instrumentation and stabilization, the right ovary and ovarian ligament were accessed by use of...
To evaluate whether guaifenesin can prevent adverse anesthetic induction events caused by propofol and whether a guaifenesin-propofol induction combination has brief cardiovascular effects commensurate with rapid drug washout.
8 healthy adult horses.
Guaifenesin was administered IV for 3 minutes followed by IV injection of a bolus of propofol (2 mg...
The aim of the study was to describe the pharmacokinetics and selected pharmacodynamics of intravenous dexmedetomidine in horses. Eight adult horses received 5 μg/kg dexmedetomidine IV . Blood samples were collected before and for 10 h after drug administration to determine dexmedetomidine plasma concentrations. Pharmacokinetic parameters were calc...
To determine the magnitude and duration of sevoflurane minimum alveolar concentration (MAC) reduction following a single intravenous (IV) dose of methadone in cats.
Prospective experimental study.
Eight (four females and four males) healthy mixed-breed adult (1-2 years) cats weighing 5.82 ± 0.42 kg.
Anesthesia was induced and maintained with sevofl...
A dog model was developed to study visceral pain by stimulating the ovarian ligament.
Prospective experimental trial.
Twelve 1-year old female hound dogs weighing 25.7 ± 3.6 kg.
Dogs were anesthetized with sevoflurane. The right ovary was accessed via laparoscopy. A suture was placed around the ovarian ligament and exteriorized through the abdomina...
To compare cardiovascular effects of sevoflurane alone and sevoflurane plus an IV infusion of lidocaine in horses. Animals-8 adult horses.
Each horse was anesthetized twice via IV administration of xylazine, diazepam, and ketamine. During 1 anesthetic episode, anesthesia was maintained by administration of sevoflurane in oxygen at 1.0 and 1.5 times...
To determine effects of a continuous rate infusion of lidocaine on the minimum alveolar concentration (MAC) of sevoflurane in horses.
8 healthy adult horses.
Horses were anesthetized via IV administration of xylazine, ketamine, and diazepam; anesthesia was maintained with sevoflurane in oxygen. Approximately 1 hour after induction, sevoflurane MAC...
DiMaio Knych, H.K., Steffey, E.P., Deuel, J.L., Shepard, R.A., Stanley, S.D. Pharmacokinetics of yohimbine following intravenous administration to horses. J. vet. Pharmacol. Therap.34, 58–63.
Yohimbine is an alpha 2 adrenergic receptor antagonist used most commonly in veterinary medicine to reverse the effects of the alpha 2 receptor agonists, xyla...
Digital perfusion pressure (DPP) equals mean arterial pressure (MAP) at the hoof coronet minus digital interstitial pressure (DIP) within the hoof. To test whether lamellar blood flow (LBF) changes proportionately to DPP, anesthesia was induced and maintained with isoflurane in six horses to target a MAP of 60 mmHg. Arterial, venous, and hoof inter...
To test a hypothesis predicting that isoflurane would interfere with cerebrovascular autoregulation in horses and to evaluate whether increased mean arterial blood pressure (MAP) would increase cerebral blood flow and intracranial pressure (ICP) during isoflurane anesthesia.
6 healthy adult horses.
Horses were anesthetized with isoflurane at a cons...
Yohimbine is an alpha 2 adrenergic receptor antagonist, which has been shown to counteract the CNS depressant effects of alpha 2 receptor agonists in a number of species. Recently, our laboratory identified yohimbine in the absence of detectable concentrations of an alpha 2 agonist in a regulatory sample collected from a horse racing in California....
To characterize cardiovascular, respiratory and biochemical effects and recovery behavior associated with a 3-hour continuous infusion of a micellar microemulsion propofol formulation in horses.
Prospective experimental trial.
Six healthy adult horses, 9 +/- 2 years old and weighing 557 +/- 14 kg.
All horses received xylazine (1 mg kg(-1), IV) 5 mi...
To define the pharmacokinetic profile of propofol 5% microemulsion formulation in horses.
First, propofol was administered as bolus injection (2 mg kg(-1)) to six xylazine-sedated horses. Secondly, after sedation and bolus injection, propofol was maintained with continuous infusion for 3 h [8.1 (sd 3.2) mg kg(-1) h(-1)] to the same six horses. Thir...
To verify the isoflurane anesthetic minimum alveolar concentration (MAC)-sparing effect of a previously administered target plasma fentanyl concentration of 16 ng/mL and characterize an anticipated further sparing in isoflurane MAC associated with higher target plasma fentanyl concentrations.
8 horses.
Horses were assigned 2 of 3 target plasma fent...
We hypothesized that propofol can produce rapidly-reversible, dose-dependent standing sedation in horses.
Prospective randomized, blinded, experimental trial.
Twelve healthy horses aged 12 +/- 6 years (mean +/- SD), weighing 565 +/- 20 kg, and with an equal distribution of mares and geldings.
Propofol was administered as an intravenous bolus at one...
Objective:
To compare characteristics of horses recovering from 4 hours of desflurane anesthesia with and without immediate postanesthetic IV administration of propofol and xylazine. Animals-8 healthy horses (mean +/- SEM age, 6.6 +/- 1.0 years; mean body weight, 551 +/- 50 kg).
Procedures:
Horses were anesthetized twice. Both times, anesthesia...
According to Starling forces, colloid oncotic pressure COP is an important determinant of fluid distribution between the vascular and extra-vascular space. The influence of common anesthetic management on plasma COP has not been reported in horses. It is necessary to seek this information preliminary to more in depth study of systemically ill horse...
Steffey, E.P., Kelly, A.B., Farver, T.B. & Woliner, M.J. Cardiovascular and respiratory effects of acetylpromazine and xylazine on halothane-anesthetized horses. J. vet. Pharmacol. Therap. 8, 290–302.
Circulatory and respiratory effects of intravenously administered acetylpromazine (0.033 and 0.067 mg/kg) and xylazine (0.5 and 1.0 mg/kg) were studi...
To characterize the pharmacokinetics of fentanyl and the tolerance of foals to the drug following a single application of a commercially available transdermal system (TS).
Prospective experimental study.
Six (two male, four female) foals aged 4-8 days, weighing 56-74 kg.
After placement of a jugular sampling catheter, one fentanyl TS (FTS) containi...
To test the hypothesis that head-down positioning in anesthetized horses increases intracranial pressure (ICP) and decreases cerebral and spinal cord blood flows.
6 adult horses.
For each horse, anesthesia was induced with ketamine hydrochloride and xylazine hydrochloride and maintained with 1.57% isoflurane in oxygen. Once in right lateral recumbe...
The influence of sleep on the equine electroencephalogram (EEG) has not been well documented.
The objectives were to develop a noninvasive method of electrode placement for recording the EEG in horses and to establish normal EEG parameters for the various states of vigilance. Findings are compared with previously published reports on equine sleep b...
IntroductionDrug Delivery29Standing Sedation and TranquilizationPreparation for ImmobilizationInduction of ImmobilizationComplications Associated with Chemical Immobilization in ElephantsFailure of Sedation or Immobilization29Local AnesthesiaAnalgesicsNarcotic Immobilizing AgentsNonnarcotic Immobilizing AgentsShort-acting Tranquilizers8,29,101Long-...
To assess the changes in colloid osmotic pressure (COP) in horses undergoing surgery for colic.
Prospective clinical evaluation.
Twenty-nine adult horses presented for emergency laparotomy.
Horses were premedicated with intravenous (IV) xylazine and anesthesia was induced with ketamine, diazepam and guaifenesin and was maintained with isoflurane as...
To investigate the changes in colloid osmotic pressure (COP) and total protein concentrations during routine general anesthesia in horses.
Prospective, clinical study.
Twelve adult healthy horses aged 9.1 +/- 4.7 years and weighing 474 +/- 79 kg presented for elective surgery and 14 adult horses aged 8.7 +/- 7.3 years and weighing 510 +/- 85 kg.
Al...
In order to evaluate its potential as an adjunct to inhalant anaesthesia in horses, the pharmacokinetics of fentanyl must first be determined.
To describe the pharmacokinetics of fentanyl and its metabolite, N-[1-(2-phenethyl-4-piperidinyl)maloanilinic acid (PMA), after i.v. administration of a single dose to horses that were awake in Treatment 1 a...
To compare anesthesia-related events associated with IV administration of 2 novel micellar microemulsion preparations (1% and 5%) and a commercially available formulation (1%) of propofol in horses. Animals-9 healthy horses.
On 3 occasions, each horse was anesthetized with 1 of the 3 propofol formulations (1% or 5% microemulsion or 1% commercial pr...
Fentanyl decreases the minimum alveolar concentration (MAC) of inhaled anaesthetics and has been used clinically to reduce the requirements of other anaesthetic drugs in humans and small animals. We hypothesized that i.v. fentanyl would decrease the MAC of isoflurane in horses in a dose-dependent manner.
Following determination of baseline MAC of i...
To characterize behavioral and physiological responses to short-term, unsupplemented intravenous (IV) anesthesia in healthy horses at high altitude (2240 m), and to test the hypothesis that the dose of butorphanol modifies the response of the horse to propofol anesthesia following xylazine pre-medication.
Randomized prospective butorphanol dose cro...
To describe the effects of changes in circuit volume and oxygen inflow rate on inspired oxygen concentration for a large animal circle anesthetic system.
A large animal circle anesthetic system, a 10 L/min flowmeter, and 20- and 40-L breathing bags.
Circuit volume was determined by a carbon dioxide dilution technique. Oxygen flow rates of 3, 6, and...
To describe a sling recovery system (Anderson Sling) for horses and to evaluate outcome of high-risk horses recovered from general anesthesia by a sling.
Retrospective study.
Horses (n=24) recovered from general anesthesia.
Complete medical and anesthetic records (1996-2003) for horses recovered from general anesthesia using the Anderson Sling syst...
To evaluate the use of xylazine and ketamine for total i.v. anesthesia in horses.
8 horses.
Anesthetic induction was performed on 4 occasions in each horse with xylazine (0.75 mg/kg, i.v.), guaifenesin (75 mg/kg, i.v.), and ketamine (2 mg/kg, i.v.). Intravenous infusions of xylazine and ketamine were then started by use of 1 of 6 treatments as foll...
To quantitate effects of dose of sevoflurane and mode of ventilation on cardiovascular and respiratory function in horses and identify changes in serum biochemical values associated with sevoflurane anesthesia.
6 healthy adult horses.
Horses were anesthetized twice: first, to determine the minimum alveolar concentration (MAC) of sevoflurane and sec...
To quantitate the effects of desflurane and mode of ventilation on cardiovascular and respiratory functions and identify changes in selected clinicopathologic variables and serum fluoride values associated with desflurane anesthesia in horses.
6 healthy adult horses.
Horses were anesthetized on 2 occasions: first, to determine the minimum alveolar...
Ahealthy, 565-kg, 14-year-old Quarter Horse gelding, negative for equine protozoal myelitis on serum Western blot and for hyperkalemic periodic paralysis (HYPP) by polymerase chain reaction, was selected for use in an electrophysiology study performed under inhalation anesthesia. The study was performed by following the guidelines of an Animal Use...
The superficial (SDF) and deep digital flexor (DDF) muscles are critical for equine forelimb locomotion. Knowledge of their mechanical properties will enhance our understanding of limb biomechanics. Muscle contractile properties derived from architectural-based algorithms may overestimate real forces and underestimate shortening capacity because of...
There is a need for a device for improved management of the airway of small laboratory animals during general anaesthesia. This report introduces such a device, referred to here as the airway device (AD). The AD has some similarity to the laryngeal mask airway (LMA) developed for human patients, but the mask portion of the device is specifically de...
To quantitate the dose- and time-related effects of IV administration of xylazine and detomidine on urine characteristics in horses deprived of feed and water.
6 horses.
Feed and water were withheld for 24 hours followed by i.v. administration of saline (0.9% NaCI) solution, xylazine (0.5 or 1.0 mg/kg), or detomidine (0.03 mg/kg). Horses were treat...
To determine whether high intracranial pressure (ICP) during spontaneous ventilation (SV) in anesthetized horses coincides with an increase in intracranial elastance (ie, change in ICP per unit change of intracranial volume).
6 adult horses.
Anesthesia was induced and maintained in each horse for 5 hours with isoflurane at a constant dose equal to...
To qualitatively and quantitatively evaluate the characteristics of desflurane with regard to the induction of and recovery from anesthesia in cats.
6 cats.
Anesthesia was induced and maintained with desflurane in oxygen. Individual minimum alveolar concentration (MAC) values were determined; anesthesia was maintained at 1.25 x MAC for a total anes...
To quantitate the dose and time-related effects of morphine sulfate on the anesthetic sparing effect of xylazine hydrochloride in halothane-anesthetized horses and determine the associated plasma xylazine and morphine concentration-time profiles.
6 healthy adult horses.
Horses were anesthetized 3 times to determine the minimum alveolar concentratio...
To develop and test an experimental model for in vivo short-term recording of peak isometric forces of the digital flexor muscles in the forelimb of adult horses.
In vivo experimental study.
Four healthy, anesthetized, adult Thoroughbred horses (3 to 7 years old; 527 +/- 87 kg)
In dorsal recumbency, ulnar and median nerves were exposed and instrume...
The minimum alveolar concentration (MAC) of an inhaled anaesthetic describes its potency as a general anaesthetic. Individuals vary in their sensitivity to anaesthetics and we sought to determine whether an individual animal's sensitivity to inhaled anaesthetics would be maintained across different agents.
Six female mongrel cats, age 2 yr (range 1...
To test the hypothesis that isoflurane-anesthetized horses during controlled ventilation and spontaneous ventilation exhibit temporal changes in cerebral hemodynamics, as measured by intracranial pressure and cerebral perfusion pressure, that reflect temporal changes in systemic arterial pressure.
6 healthy adult horses.
Horses were anesthetized in...
To characterize halothane and sevoflurane anesthesia in spontaneously breathing rats.
16 healthy male Sprague-Dawley rats.
8 rats were anesthetized with halothane and 8 with sevoflurane. Minimum alveolar concentration (MAC) was determined. Variables were recorded at anesthetic concentrations of 0.8, 1.0, 1.25, and 1.5 times the MAC of halothane and...
Minimum alveolar concentration (MAC) of an inhalant is an indicator of its anesthetic potency. Individuals vary in their sensitivity to anesthetic agents as demonstrated by different individual MAC values. We hypothesized that individual animal sensitivity would be maintained with different inhalant anesthetics.
As part of separate studies, six fem...
Isoflurane (ISO) is the most commonly administered feline inhalant anesthetic in North America. A newer agent, sevoflurane (SEVO), may provide faster induction and recovery from anesthesia based on its physical characteristics. Accordingly, we compared some induction and recovery characteristics of ISO and SEVO in healthy cats.
Six female DSH cats...
To quantitate dose- and time-related magnitudes of interactive effects of morphine (MOR) and isoflurane (ISO) in horses and to characterize pharmacokinetics of MOR in plasma and the ventilatory response to MOR during administration of ISO.
6 adult horses.
Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of ISO...
To measure the effects of isoflurane end-tidal concentration and mode of ventilation (spontaneous vs controlled) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in horses.
adult horses of various breeds.
Anesthesia was induced and maintained with isoflurane in O2 in 6 healthy, unmedicated, adult horses. Using a subarachnoid str...
The volatile anaesthetic sevoflurane is degraded to fluoride (F-) and a vinyl ether (Compound A), which have the potential to harm kidney and liver. Whether renal and hepatic injuries can occur in horses is unknown. Cardiopulmonary, biochemical and histopathological changes were studied in six healthy thoroughbred horses undergoing 18 h of low-flow...
To develop a method for surgical placement of a commercial microsensor intracranial pressure (ICP) transducer and to characterize normal ICP and cerebral perfusion pressures (CPP) in conscious adult horses.
6 healthy castrated male adult horses (1 Holsteiner, 1 Quarter Horse, and 4 Thoroughbreds).
Anesthesia was induced and maintained by use of iso...
Objective To quantitate the dose- and time-related magnitude of the anesthetic sparing effect of, and selected physiological responses to detomidine during isoflurane anesthesia in horses.
Study design Randomized cross-over study.
Animals Three, healthy, young adult horses weighing 485 ± 14 kg.
Methods Horses were anesthetized on two occasions to d...
To characterize the effect of general anesthesia and minor surgery on renal function in horses.
9 mares with a mean (+/- SE) age and body weight of 9+/-2 years and 492+/-17 kg, respectively.
The day before anesthesia, urine was collected (catheterization) for 3 hours to quantitate baseline values, and serum biochemical analysis was performed. The f...
Inhalant anesthetics may interfere with normal cerebrovascular autoregulation. It was, therefore, hypothesized that intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in isoflurane-anesthetized horses would be especially sensitive to body and head position because of the potential for large hydrostatic gradients between the brain and...
Ilkiw, J. E., Farver, T. B., Suter, C., McNeal, D., Steffey, E. P. The effect of intravenous administration of variable‐dose flumazenil after fixed‐dose ketamine and midazolam in healthy cats. J. vet. Pharmacol. Therap. 25, 181–188.
The effects of intravenous administration of variable‐dose flumazenil (0, 0.001, 0.005, 0.01, and 0.1 mg/kg) after ke...
This study was conducted to determine the isoflurane (ISO) minimum alveolar concentration (MAC) reduction induced by nitrous oxide in cats. Twelve cats (four females, eight males; 3.8–8.8 kg; 2–3 years) were anesthetized with only ISO in O2. Ventilation was spontaneous. The MAC of ISO was determined at four concentrations of N2O (0, 30, 50, and 70%...
Alpha-2 agonists cause transient dose-related increase in urine flow in normal horses. Although important clinically, effects of these drugs in dehydrated animals are not known. The purpose of this study was to describe the influence of xylazine (XYL) and detomidine (DET) on urine flow in mares deprived of food and water for 24 hours.
Six clinicall...
The magnitude of respiratory depression in equidae anesthetized with isoflurane has not been thoroughly described. The aim of this study was to quantify changes in ventilation as a function of isoflurane (ISO) dose in the horse.
Anesthesia was induced and maintained in five healthy adult horses weighing 564 ± 52 kg (mean ± SD) in left lateral recum...
The purpose of this study was to characterize urine flow and biochemical parameters in horses given xylazine (XYL) and anesthetized with ketamine and isoflurane.
Nine mares [9 ± 2 (mean ± SE) years; 492 ± 17 kg] were studied. They were anesthetized for 2 hours in support of a campus-approved, laboratory-based orthopedic study. The day prior to anes...
The purpose of this study was to evaluate selected physiological and behavioral responses to xylazine (XYL)–butorphanol (BUTOR) supplemented propofol (PROP) anesthesia in horses and the influence of BUTOR dose on outcome.
Eight horses [13 ± 2 (mean ± SE) year], weighing 524 ± 9 kg were anesthetized three times with at least 3 weeks between each ane...
As a cerebral vasodilator, isoflurane (ISO) can interfere with normal cerebrovascular autoregulation and may exacerbate cerebral perfusion pressure (CPP) changes in horses brought about by drugs that decrease mean arterial pressure (MAP) and by body positions that alter the hydrostatic gradient between brain and heart. It was, therefore, hypothesiz...
Both desflurane and sevoflurane offer theoretical and practical advantages over other inhalation anesthetics for horses. The lower solubility of both agents provides improved control of delivery and helps to counteract the confounding influence of the voluminous patient breathing circuit commonly used for anesthetizing horses. The lower solubility...
Administration of alpha-2 agonists to horses produces a variety of behavioral effects (sedation, somnolence, analgesia), and physiological effects. One of the most significant beneficial effects of administering alpha-2 agonists is the degree of analgesia they provide. Alpha-2 agonists have been the mainstay of analgesia for colic pain in horses si...
REGIONAL ADMINISTRATION: There is limited, but convincing, evidence that epidural administration of morphine and some other mu-agonist opioids consistently relieves regional pain in horses. In addition, this effect is not accompanied by notable undesirable effects. On the other hand, a clinically important analgesic action has not been demonstrated...