Analyze Diet

Topic:Clinical Study

Clinical studies in equine research involve the systematic investigation of health and disease in horses through structured scientific methods. These studies aim to evaluate the safety and efficacy of treatments, understand disease mechanisms, and improve veterinary care practices. Clinical studies can include randomized controlled trials, observational studies, and case-control studies. They may focus on various aspects such as pharmacokinetics, therapeutic interventions, and diagnostic techniques. This page compiles peer-reviewed research studies and scholarly articles that explore the design, implementation, and findings of clinical studies in equine medicine, providing insights into their impact on horse health and veterinary practices.
Changes in growth of the hoof wall and hoof morphology in response to regular periods of trotting exercise in Standardbreds.
American journal of veterinary research    November 3, 2009   Volume 70, Issue 11 1354-1364 doi: 10.2460/ajvr.70.11.1354
Faramarzi B, Thomason JJ, Sears WC.To quantitate changes in hoof wall growth and hoof morphology induced by mild exercise in Standardbreds. Methods: 18 Standardbreds. Methods: Horses were exercised at approximately 6 m/s (4,200 to 5,600 m/d) on 4 d/wk for 17 weeks. Both exercise (n = 9) and nonexercise (control group; 9) groups were housed in a large paddock throughout the study. At the beginning and end of the study, right forelimb feet of all horses were digitally photographed and underwent magnetic resonance imaging. Hoof wall measurements were obtained from the images to evaluate hoof wall growth and morphometric variables....
Comparison of characteristics and enzymatic products of leukocytes in the skin and laminar tissues of horses administered black walnut heartwood extract or lipopolysaccharide.
American journal of veterinary research    November 3, 2009   Volume 70, Issue 11 1383-1390 doi: 10.2460/ajvr.70.11.1383
Riggs LM, Krunkosky TM, Noschka E, Boozer LA, Moore JN, Robertson TP, Peroni JF.To compare characteristics and enzymatic products of leukocytes detected in the skin and laminar tissues of horses administered black walnut heartwood extract (BWHE) and horses administered purified lipopolysaccharide (LPS). Methods: 25 healthy 5- to 15-year-old horses. Methods: Horses were randomly assigned to receive LPS (20 ng of O55:B5 Escherichia coli endotoxin/kg; n = 5) IV or 6 L of BWHE (10) or water (control group; 10) via nasogastric intubation. Horses were euthanatized 12 hours after treatment or at onset of Obel grade 1 lameness. Laminar tissue samples and skin samples from the mid...
Effect of topical application of 1% diclofenac sodium liposomal cream on inflammation in healthy horses undergoing intravenous regional limb perfusion with amikacin sulfate.
American journal of veterinary research    November 3, 2009   Volume 70, Issue 11 1323-1325 doi: 10.2460/ajvr.70.11.1323
Levine DG, Epstein KL, Neelis DA, Ross MW.To determine whether topical application of 1% diclofenac sodium cream would decrease inflammation at sites of IV regional limb perfusion (IVRLP) in healthy horses. Methods: 6 healthy adult horses (12 forelimbs). Methods: Bilateral IVRLP with 2.5 g of amikacin sulfate was performed twice in each horse, with 24 hours between each session. Horses were treated with topical 1% diclofenac liposomal cream (treated limbs) or a placebo cream (control limbs). All injection sites were evaluated before the first IVRLP session and 24 hours after the second session by means of ultrasonographic examination ...
The pharmacokinetics of the weakly protein-bound anionic compound diatrizoate in serum and synovial fluid of the horse.
Pharmaceutical research    October 30, 2009   Volume 27, Issue 1 143-150 doi: 10.1007/s11095-009-9988-x
Frost AB, Larsen F, Larsen SW, Østergaard J, Thomsen MH, Stürup S, Andersen PH, Larsen C.To establish a pharmacokinetic model for the model drug, sodium diatrizoate (DTZ), allowing joint disappearance kinetics to be estimated from serum appearance kinetics following intra-articular administration, and to calculate the relative joint exposure after intravenous and intra-articular DTZ administration (F(iv/IA)). Methods: Each of five horses received an aqueous solution of 3.9 mg/kg sodium diatrizoate both intravenously and intra-articularly separated by a one-week wash out period. Serum and synovial samples were collected over 7 h and analyzed for content of model compound using indu...
Abdominal wall reconstruction using biological tissue grafts.
AORN journal    October 29, 2009   Volume 90, Issue 4 513-524 doi: 10.1016/j.aorn.2009.05.024
Brown P.Synthetic mesh products have been used to repair abdominal wall defects (eg, hernias) for many years. Biological mesh products are now available as an option when synthetic mesh products are not appropriate. To correctly prepare biological tissue grafts for use in the OR, perioperative nurses must understand the types of grafts available. Biological tissue grafts may be harvested from human, porcine, bovine, or equine hosts and from skin, pericardium, or small intestine submucosa.
Effect of the administration of an oral hyaluronan formulation on clinical and biochemical parameters in young horses with osteochondrosis.
Veterinary and comparative orthopaedics and traumatology : V.C.O.T    October 29, 2009   Volume 22, Issue 6 455-459 doi: 10.3415/VCOT-09-01-0001
Carmona JU, Argüelles D, Deulofeu R, Martínez-Puig D, Prades M.The aim of this study was to evaluate the clinical and biochemical effects of the administration of oral hyaluronan (Hyal-Joint [HJ]) on young horses with osteochondrosis (OC). Our hypotheses were that HJ administration is safe, would decrease the degree of synovial effusion and the concentration of nitric oxide (NO) and prostaglandin E2 (PGE2) in synovial fluid, and would increase the concentration of hyaluronic acid (HA) in plasma and synovial fluid. Eleven young horses with tarsocrural OC were included in a randomised, double-blinded, placebo-controlled pilot clinical trial. Six horses rece...
Spinal kinematics in horses with induced back pain.
Veterinary and comparative orthopaedics and traumatology : V.C.O.T    October 29, 2009   Volume 22, Issue 6 448-454 doi: 10.3415/VCOT-08-09-0088
Wennerstrand J, Gómez Alvarez CB, Meulenbelt R, Johnston C, van Weeren PR, Roethlisberger-Holm K, Drevemo S.Back problems are important contributors to poor performance in sport horses. It has been shown that kinematic analysis can differentiate horses with back problems from asymptomatic horses. The underlying mechanism can, however, only be identified in a uniform, experimental setting. Our aim was to determine if induction of back pain in a well-defined site would result in a consistent change in back movement. Back kinematics were recorded at a walk and trot on a treadmill. Unilateral back pain was then induced by injecting lactic acid into the left longissimus dorsi muscle. Additional measureme...
Characterization of pentraxin 3 in the horse and its expression in airways.
Veterinary research    October 29, 2009   Volume 41, Issue 2 18 doi: 10.1051/vetres/2009066
Ramery E, Fievez L, Fraipont A, Bureau F, Lekeux P.The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 and its expression in the horses' airway. Six healthy horses and six horses affected by recurrent airway obstruction (R.A.O.) were submitted to a dusty environment challenge. PTX3 DNA and cDNA were cloned and sequenced. PTX3 expression was evaluated by RT-qPCR, Western blotting and immunohistochemistry in bronchoalveolar lavage fluid (BALF) cells, BALF supernatant and bronchial epithelial cell...
In vitro comparison of cortical bone temperature generation between traditional sequential drilling and a newly designed step drill in the equine third metacarpal bone.
Veterinary and comparative orthopaedics and traumatology : V.C.O.T    October 29, 2009   Volume 22, Issue 6 442-447 doi: 10.3415/VCOT-09-03-0029
Bubeck KA, García-López J, Maranda LS.To compare heat generation and time to finish between a new step drill and sequential drilling in order to create a 6.2 mm pilot hole for insertion of a positive profile transfixation pin into the equine third metacarpal bone. Methods: Nine pairs of equine third metacarpal bones from cadavers of adult horses were used. Maximum temperature rise of the bone was measured continuously at the cis- and trans-cortices 1, 2 and 3 mm from the final pilot hole during creation of a 6.2 mm hole using a step drill and sequential drilling with 4.5, 5.5 and 6.2 mm drill bits. Five holes were drilled into the...
Equine neutrophil elastase in plasma, laminar tissue, and skin of horses administered black walnut heartwood extract.
Veterinary immunology and immunopathology    October 29, 2009   Volume 135, Issue 3-4 181-187 doi: 10.1016/j.vetimm.2009.10.024
de la Rebière de Pouyade G, Riggs LM, Moore JN, Franck T, Deby-Dupont G, Hurley DJ, Serteyn D.Laminitis is a local manifestation of a systemic inflammatory response that is characterized by neutrophil activation and movement of neutrophils into the laminar tissues. Given the evidence for the involvement of neutrophils in the development of laminitis, we measured concentrations of neutrophil elastase, a serine protease released from the azurophilic granules of neutrophils, in plasma, skin and laminar tissues obtained from control horses and horses given black walnut heartwood extract (BWHE) to induce laminitis. Healthy horses (5-15 years old) were randomly assigned to 4 groups: 3 experi...
Case report: Repair of a type IV Monteggia fracture in a foal.
Australian veterinary journal    October 28, 2009   Volume 87, Issue 11 463-466 doi: 10.1111/j.1751-0813.2009.00508.x
Jalim SL, McKinnon AO, Russell TM.A Monteggia fracture is a humero-radial luxation combined with a fracture of the ulna. It is a rare injury, infrequently reported in the horse. This case report describes the surgical repair of such a fracture in a 4-month-old filly.
Functional role of alpha2-adrenoceptor subtypes in the cooling-enhanced vasoconstriction of isolated cutaneous digital veins of the horse.
European journal of pharmacology    October 28, 2009   Volume 627, Issue 1-3 194-202 doi: 10.1016/j.ejphar.2009.10.046
Zerpa H, Berhane Y, Elliott J, Bailey SR.Cooling-enhanced contractile responses in cutaneous arteries have been reported to involve the activation of alpha(2C)-adrenoceptors, but their role in cutaneous veins is not clearly understood. The aim was to pharmacologically characterize the subtype of postsynaptic alpha(2)-adrenoceptors in the equine digital vein mediating contraction at two temperatures. The increase in isometric tension of endothelium-denuded equine digital vein in response to UK-14304 was studied in the absence and presence of relatively selective alpha(2)-adrenoceptor antagonists at temperatures of either 30 degrees C ...
Evaluation of indwelling intravenous catheters for the regional perfusion of the limbs of horses.
The Veterinary record    October 27, 2009   Volume 165, Issue 17 496-501 doi: 10.1136/vr.165.17.496
Kelmer G, Catasus CT, Saxton AM, Elliot SB.The feasibility of maintaining indwelling intravenous catheters in the saphenous, cephalic or palmar digital vein of horses for seven days to infuse antimicrobial drugs was investigated in 18 horses. The horses were randomly assigned to six groups according to the vein catheterised and whether they received amikacin or erythromycin. None of the catheters was replaced more than once, and 11 of the 18 catheters remained patent for all seven days. Neither the drug administered nor the vein catheterised significantly affected the survival of the catheter. In all but three cases, complications, inc...
Intravenous tramadol: effects, nociceptive properties, and pharmacokinetics in horses.
Veterinary anaesthesia and analgesia    October 23, 2009   Volume 36, Issue 6 581-590 doi: 10.1111/j.1467-2995.2009.00492.x
Dhanjal JK, Wilson DV, Robinson E, Tobin TT, Dirikolu L, Dirokulu L.To determine the optimal dose, serum concentrations and analgesic effects of intravenous (IV) tramadol in the horse. Two-phase blinded, randomized, prospective crossover trial. Seven horses (median age 22.5 years and mean weight 565 kg). Horses were treated every 20 minutes with incremental doses of tramadol HCl (0.1-1.6 mg kg(-1)) or with saline. Heart rate, respiratory rate, step frequency, head height, and sweating, trembling, borborygmus and head nodding scores were recorded before and up to 6 hours after treatment. In a second study, hoof withdrawal and skin twitch reflex latencies (HWRL ...
Determination of the stiffness of the equine cervical spine.
Veterinary journal (London, England : 1997)    October 21, 2009   Volume 186, Issue 3 338-341 doi: 10.1016/j.tvjl.2009.09.015
Pagger H, Schmidburg I, Peham C, Licka T.This aim of this study was to test the hypothesis that the stiffness of the equine cervical spine depends on the direction of force applied and on spinal position. Muscles and nuchal ligament were removed from the cervical spines of 17 horses that were without a history of cervical or neurological disease. The cervical spines were then flexed/extended dorsoventrally (with the spine straight and with the occiput rotated 30° against T1) and laterolaterally. Mean dorsoventral stiffness was 297 N/m (± 135) in flexion, 1347 N/m (± 2083) in extension, 421 N/m (± 164) in lateral flexion, 279 N/m ...
Nuchal crest avulsion fracture in 2 horses: a cause of headshaking.
Journal of the South African Veterinary Association    October 17, 2009   Volume 80, Issue 2 111-113 doi: 10.4102/jsava.v80i2.183
Voigt A, Saulez MN, Donnellan CM.The medical records of 2 Thoroughbred horses that developed headshaking after blunt trauma to the occipital region are reviewed. The history, signalment, clinical signs, diagnostic methods, diagnosis and treatment were recorded in each case. Both horses displayed headshaking, while one horse repeatedly lifted its upper lip and pawed excessively at the ground. In both horses, diagnostic imaging of the occipital region revealed avulsion fragments of the nuchal crest and a nuchal desmitis in association with hyperfibrinogenaemia. The presence of an avulsion fragment of the nuchal crest with assoc...
Factors associated with likelihood of horses having a high serum Streptococcus equi SeM-specific antibody titer.
Journal of the American Veterinary Medical Association    October 16, 2009   Volume 235, Issue 8 973-977 doi: 10.2460/javma.235.8.973
Boyle AG, Sweeney CR, Kristula M, Boston R, Smith G.To identify factors associated with an increased likelihood that horses would have a serum Streptococcus equi SeM-specific antibody titer > or = 1:1,600. Methods: Cross-sectional study. Methods: 188 healthy client-owned horses. Methods: A single serum sample from each horse was tested for SeM-specific antibody titer with an ELISA. Multivariate logistic regression was used to identify factors associated with having a titer > or = 1:1,600. Results: Age, breed, and vaccination status were significantly associated with the likelihood of having a titer > or = 1:1,600. The odds of having a ...
Detection of urine and blood clenbuterol following short-term oral administration in the horse.
Immunopharmacology and immunotoxicology    October 14, 2009   Volume 32, Issue 1 171-176 doi: 10.3109/08923970903179688
Chuang MS, Huang HH, Dixon KM, Chen KS, Mao CL, Chen CL.The pharmacokinetics of clenbuterol in equine urine and blood was investigated. Methods: Urine and blood samples were collected following 3-day multiple oral administrations. The samples were examined using enzyme-linked immunosorbent assay and further confirmed by solid phase extraction and capillary electrophoresis. Results: Urinary clenbuterol was detectable until day 14 after the last dose. The urinary excretion of clenbuterol was characterized by a biphasic pattern. The half-lives of the bi-exponential elimination (t(1/2alpha) and t(1/2beta)) for urinary clenbuterol were about 12.1 and 48...
Treatment of septicaemia and severe bacterial infections in foals with a new cefquinome formulation: a field study.
DTW. Deutsche tierarztliche Wochenschrift    October 10, 2009   Volume 116, Issue 9 316-320 
Rohdich N, Zschiesche E, Heckeroth A, Wilhelm C, Leendertse I, Thomas E.A multicentre field study was conducted in accordance with VICH Guideline on Good Clinical Practice (VICH 2000) to confirm the efficacy and safety of a new formulation of cefquinome for the treatment of naturally occurring severe bacterial infections and septicaemia in foals. Thirty-nine foals suffering from severe bacterial infections (such as pneumonia, gastro-enteritis, arthritis, omphalitis, or wound infections) or acute septicaemia were treated twice daily with the test product (1 mg cefquinome/kg body weight) intravenously for three days and then intramuscularly for three to 11 days. Inv...
International Equine Ophthalmology Consortium (IEOC) Symposium.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 606-607 doi: 10.2746/042516409x447789
Gilger BC, Brooks DE.This first IEOC symposium met its goals of gathering a group of leading equine ophthalmology clinicians and researchers to identify the challenges of the field. To facilitate collaboration, notes from round-table discussions, including the ideas and plans that were discussed are being complied and will be distributed to the attendees. Development of an IEOC membership organisation and website was discussed and supported by the group in an effort further to advance the science of equine ophthalmology. To present results from the collaborations made at this first IEOC meeting, an IEOC mini-sympo...
Analgesic effect of butorphanol in ponies following castration.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 552-556 doi: 10.2746/042516409x391024
Love EJ, Taylor PM, Clark C, Whay HR, Murrell J.In the UK butorphanol has a marketing authorisation for administration to horses for sedation in combination with detomidine, and at a higher dose (0.1 mg/kg bwt), for the alleviation of pain. There is only a limited number of clinical studies designed to examine the analgesic effects of butorphanol administration following surgery. Objective: To investigate the effect of premedication with butorphanol on post operative pain following castration under general anaesthesia in ponies. Objective: Ponies receiving butorphanol would experience less pain after castration than ponies that did not rece...
A glycogen synthase 1 mutation associated with equine polysaccharide storage myopathy and exertional rhabdomyolysis occurs in a variety of UK breeds.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 597-601 doi: 10.2746/042516409x407611
Stanley RL, McCue ME, Valberg SJ, Mickelson JR, Mayhew IG, McGowan C, Hahn CN, Patterson-Kane JC, Piercy RJ.A glycogen synthase (GYS1) mutation has been described in horses with histopathological evidence of polysaccharide storage myopathy (PSSM) in the USA. It is unknown whether the same mutation is present in horses from the UK. Objective: To determine whether the GYS1 mutation occurs in UK horses with histopathological evidence of PSSM and exertional rhabdomyolysis. Objective: The R309H GYS1 mutation is present in a variety of UK horse breeds and that the mutation is commonly associated with exertional rhabdomyolysis. Methods: DNA was extracted from 47 muscle or blood samples from UK horses with ...
Management and assessment of prognosis after gastrocnemius disruption in Thoroughbred foals: 28 cases (1993-2007).
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 541-546 doi: 10.2746/042516409x407657
Tull TM, Woodie JB, Ruggles AJ, Reimer JR, Embertson RM, Hopper SA, Bramlage LR.Few studies have evaluated the athletic prognosis of foals affected by gastrocnemius disruption. Objective: To examine the diagnosis and management of gastrocnemius disruption in Thoroughbred (TB) foals, determine short-term survival rate and assess future racing performance. The hypothesis was that Thoroughbred foals with gastrocnemius disruption are able to perform as racehorses comparably to their age matched maternal siblings. Methods: The medical records of foals diagnosed with gastrocnemius muscle disruption were reviewed. Information on training and racing was acquired from published wo...
Nuclear scintigraphic assessment of the thoracolumbar synovial intervertebral articulations.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 534-540 doi: 10.2746/042516409x376940
Gillen A, Dyson S, Murray R.The results of nuclear scintigraphic examination of the thoracolumbar synovial intervertebral articulations (facet joints) have to date been poorly documented. Objective: To establish an objective scintigraphic grading system for the facet joints; to investigate the relationship between the presence or absence of clinical signs of back pain and increased radiopharmaceutical uptake (IRU); and to compare the results of scintigraphy and radiography. Methods: Nuclear scintigraphic images of the 13th thoracic (T13) to first lumbar (L1) vertebrae were graded subjectively (visual assessment of the im...
Radiographic retrospective study of the caudal cervical articular process joints in the horse.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 518-524 doi: 10.2746/042516409x391015
Down SS, Henson FM.Arthropathy of the caudal cervical articular process joints (APJs) in the horse is documented as a cause of ataxia and paresis secondary to spinal cord compression. Enlargement of the caudal APJs is reported to increase with age, but there are no known associations of any other factors. No association of the degree of APJ enlargement with neurological signs seen has been documented. This study investigated the associations of cervical APJ enlargement at the C5-C6 and C6-C7 articulations with case subject details (breed, age, sex, usage) and clinical signs. Objective: To ascertain if there are ...
Results and complications of a novel technique for primary castration with an inguinal approach in horses.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 547-551 doi: 10.2746/042516409x415018
Kummer M, Gygax D, Jackson M, Bettschart-Wolfensberger R, Fürst A.Complications associated with equine castration can have medical and financial consequences. This retrospective study investigated a novel method of castration via an inguinal approach in mature stallions and compared the incidence of complications with other methods. Objective: Castration via an inguinal approach has a low complication rate at the site of surgery compared with other castration techniques. Methods: Mature stallions (n = 238) were castrated under general anaesthesia in dorsal recumbency using an inguinal approach. The vaginal process was incised, the spermatic cord ligated twic...
Anaesthetic and cardiorespiratory effects of propofol at 10% for induction and 1% for maintenance of anaesthesia in horses.
Equine veterinary journal    October 7, 2009   Volume 41, Issue 6 578-585 doi: 10.2746/042516409x407620
Muir WW, Lerche P, Erichson D.Studies have demonstrated the clinical usefulness of propofol for anaesthesia in horses but the use of a concentrated solution requires further investigation. Objective: To determine the anaesthetic and cardiorespiratory responses to a bolus injection of 10% propofol solution in mature horses. Methods: Three randomised crossover experimental trials were completed. Trial 1: 6 horses were selected randomly to receive 10% propofol (2, 4 or 8 mg/kg bwt i.v.). Trial 2: 6 horses received 1.1 mg/kg bwt i.v. xylazine before being assigned at random to receive one of 5 different doses (1-5 mg/kg bwt) o...
Anti-inflammatory effects of intravenously administered lidocaine hydrochloride on ischemia-injured jejunum in horses.
American journal of veterinary research    October 3, 2009   Volume 70, Issue 10 1259-1268 doi: 10.2460/ajvr.70.10.1259
Cook VL, Jones Shults J, McDowell MR, Campbell NB, Davis JL, Marshall JF, Blikslager AT.To investigate effects of lidocaine hydrochloride administered IV on mucosal inflammation in ischemia-injured jejunum of horses treated with flunixin meglumine. Methods: 24 horses. Methods: Horses received saline (0.9% NaCl) solution (SS; 1 mL/50 kg, IV [1 dose]), flunixin meglumine (1 mg/kg, IV, q 12 h), lidocaine (bolus [1.3 mg/kg] and constant rate infusion [0.05 mg/kg/min], IV, during and after recovery from surgery), or both flunixin and lidocaine (n = 6/group). During surgery, blood flow was occluded for 2 hours in 2 sections of jejunum in each horse. Uninjured and ischemia-injured jejun...
High-mobility group box chromosomal protein 1 as a potential inflammatory biomarker of joint injury in Thoroughbreds.
American journal of veterinary research    October 3, 2009   Volume 70, Issue 10 1230-1235 doi: 10.2460/ajvr.70.10.1230
Brown MP, Trumble TN, Merritt KA.To investigate effects of osteochondral injury on high-mobility group box chromosomal protein 1 (HMGB-1) concentrations in synovial fluid (SF) from Thoroughbreds and to compare these results with radiographic and arthroscopic scores of severity of joint injury. Methods: 40 clinically normal rested Thoroughbreds (group 1) and 45 Thoroughbreds with osteochondral injury as a result of racing. Methods: SF was obtained from the metacarpophalangeal (MCP) joints, metatarsophalangeal (MTP) joints, middle carpal joints, and radiocarpal joints. For group 2, radiographic and arthroscopic scores were dete...
Effects of high plasma fentanyl concentrations on minimum alveolar concentration of isoflurane in horses.
American journal of veterinary research    October 3, 2009   Volume 70, Issue 10 1193-1200 doi: 10.2460/ajvr.70.10.1193
Knych HK, Steffey EP, Mama KR, Stanley SD.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. Methods: 8 horses. Methods: Horses were assigned 2 of 3 target plasma fentanyl concentrations (16, 24, and 32 ng/mL), administered in ascending order. Following determination of baseline MAC, horses received a loading dose of fentanyl followed by a constant rate infusion; MAC determination was performed i...