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Nichols CL, Doherty TJ, Schumacher J, Jones PD, Sun X. Dexmedetomidine prolongs the duration of action of mepivacaine on anesthesia of the palmar digital nerves of horses. Am J Vet Res 2022; 83:114-118. [PMID: 34851852 DOI: 10.2460/ajvr.20.10.0188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine whether palmar digital nerve (PDN) blockade in horses with a combination of dexmedetomidine and mepivacaine would block the response to mechanical force applied to the digit longer than would anesthetizing these nerves with mepivacaine alone or dexmedetomidine alone. ANIMALS 8 mares with no signs of lameness. PROCEDURES In a randomized, crossover, blinded, experimental study, both PDNs of the same forelimb of each horse were anesthetized by perineural injection with either 30 mg mepivacaine alone, 250 µg of dexmedetomidine alone, or 30 mg mepivacaine combined with 250 µg of dexmedetomidine. Each horse received each treatment, and treatments were administered ≥ 2 weeks apart. The mechanical nociceptive threshold was measured at a region between the heel bulbs with the use of a digital force gauge before (baseline) and at 15-minute intervals after treatment. RESULTS The mean duration of sensory blockade of the digit was 2-fold longer when a combination of mepivacaine and dexmedetomidine was administered (371 minutes), compared with when mepivacaine alone was administered (186 minutes). Treatment with dexmedetomidine alone did not change the mechanical nociceptive threshold substantially from baseline and resulted in no clinical signs of sedation. CLINICAL RELEVANCE Results indicated that relief from digital pain provided by perineural treatment with mepivacaine for PDN blockade can be extended by adding dexmedetomidine to the injectate.
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Affiliation(s)
- Cailey L Nichols
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
| | - Thomas J Doherty
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
| | - James Schumacher
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
| | - Philip D Jones
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
| | - Xiaocun Sun
- Office of Information Technology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
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Grzeskowiak RM, Alghazali KM, Hecht S, Donnell RL, Doherty TJ, Smith CK, Anderson DE, Biris AS, Adair HS. Influence of a novel scaffold composed of polyurethane, hydroxyapatite, and decellularized bone particles on the healing of fourth metacarpal defects in mares. Vet Surg 2021; 50:1117-1127. [PMID: 33948951 PMCID: PMC8360067 DOI: 10.1111/vsu.13608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 01/04/2021] [Accepted: 01/24/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To determine the effect of a novel scaffold, designed for use in bone regeneration, on healing of splint bone segmental defects in mares. STUDY DESIGN In vivo experimental study. SAMPLE POPULATION Five adult mares (4-10 years old; mean weight, 437.7 kg ± 29 kg). METHODS Bilateral 2-cm full-thickness defects were created in the fourth metacarpal bones (MCIV) of each horse. Each defect was randomly assigned to either a novel scaffold treatment (n = 5) or an untreated control (n = 5). The scaffold was composed of polyurethane, hydroxyapatite, and decellularized bone particles. Bone healing was assessed for a period of 60 days by thermography, ultrasonography, radiography, and computed tomography (CT). Biopsies of each defect were performed 60 days after surgery for histological evaluation. RESULTS On the basis of radiographic analysis, scaffold-treated defects had greater filling (67.42% ± 26.7%) compared with untreated defects (35.88% ± 32.7%; P = .006). After 60 days, CT revealed that the density of the defects treated with the scaffolds (807.80 ± 129.6 Hounsfield units [HU]) was greater than density of the untreated defects (464.80 ± 81.3 HU; P = .004). Evaluation of histology slides provided evidence of bone formation within an average of 9.43% ± 3.7% of the cross-sectional area of scaffolds in contrast to unfilled defects in which connective tissue was predominant throughout the biopsy specimens. CONCLUSION The novel scaffold was biocompatible and supported bone formation within the MCIV segmental defects. CLINICAL SIGNIFICANCE This novel scaffold offers an effective option for filling bone voids in horses when support of bone healing is indicated.
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Affiliation(s)
- Remigiusz M. Grzeskowiak
- Department of Large Animal Clinical SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
| | - Karrer M. Alghazali
- Center for Integrative Nanotechnology SciencesUniversity of Arkansas at Little RockLittle RockArkansasUSA
| | - Silke Hecht
- Department of Small Animal Clinical SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
| | - Robert L. Donnell
- Department of Biomedical and Diagnostic SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
| | - Thomas J. Doherty
- Department of Large Animal Clinical SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
| | - Christopher K. Smith
- Department of Small Animal Clinical SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
| | - David E. Anderson
- Department of Large Animal Clinical SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
| | - Alexandru S. Biris
- Center for Integrative Nanotechnology SciencesUniversity of Arkansas at Little RockLittle RockArkansasUSA
| | - Henry S. Adair
- Department of Large Animal Clinical SciencesThe University of Tennessee College of Veterinary MedicineKnoxvilleTennesseeUSA
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Chow NS, Seddighi R, Knych HK, Sun X, Doherty TJ. Sedative effects and pharmacokinetics of detomidine when administered intravenously and intravaginally as a gel in alpacas. Vet Anaesth Analg 2020; 47:773-780. [PMID: 32863105 DOI: 10.1016/j.vaa.2020.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/29/2020] [Accepted: 07/08/2020] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To evaluate the sedative effects and pharmacokinetics of detomidine gel administered intravaginally to alpacas in comparison with intravenously (IV) administered detomidine. STUDY DESIGN Randomized, crossover, blinded experiment. ANIMALS A group of six healthy adult female Huacaya alpacas (70.3 ± 7.9 kg). METHODS Alpacas were studied on two occasions separated by ≥5 days. Treatments were IV detomidine hydrochloride (70 μg kg-1; treatment DET-IV) or detomidine gel (200 μg kg-1; treatment DET-VAG) administered intravaginally. Sedation and heart rate (HR) were evaluated at intervals for 240 minutes. Venous blood was collected at intervals for 360 minutes after treatment for analysis of detomidine, carboxydetomidine and hydroxydetomidine using liquid chromatography-tandem mass spectrometry. Measured variables were compared between treatments and over time using mixed model analysis. Data are presented as the mean ± standard error of the mean, and a p value of <0.05 was considered significant. RESULTS Onset of sedation was faster in treatment DET-IV (1.6 ± 0.2 minutes) than in treatment DET-VAG (13.0 ± 2.5 minutes). Time to maximum sedation was shorter in treatment DET-IV (8.3 ± 1.3 minutes) than in treatment DET-VAG (25 ± 4 minutes). Duration of sedation was not different between treatments. There was a significant linear relationship between sedation score and plasma detomidine concentration. HR was less than baseline for 60 and 125 minutes for treatments DET-IV and DET-VAG, respectively. The maximal decrease in HR occurred at 15 minutes for both treatments. The mean maximum plasma concentration of detomidine, time to maximum concentration and bioavailability for treatment DET-VAG were 39.6 ng mL-1, 19.9 minutes and 20%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Detomidine administration at the doses studied resulted in moderate sedation when administered IV or intravaginally to alpacas.
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Affiliation(s)
- Natalie S Chow
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
| | - Reza Seddighi
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.
| | - Heather K Knych
- K.L. Maddy Equine Analytical Chemistry Laboratory, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Xiacun Sun
- Office of Information Technology, University of Tennessee, Knoxville, TN, USA
| | - Thomas J Doherty
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
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McCracken MJ, Schumacher J, Doherty TJ, Sun X, Nichols CL, Olivarez J. Efficacy and duration of effect for liposomal bupivacaine when administered perineurally to the palmar digital nerves of horses. Am J Vet Res 2020; 81:400-405. [PMID: 32343175 DOI: 10.2460/ajvr.81.5.400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the efficacy and duration of effect for liposomal bupivacaine following perineural administration to the medial and lateral palmar digital nerves of horses. ANIMALS 9 nonlame mares. PROCEDURES For each horse, 2 mL of liposomal bupivacaine (13.3 mg/mL; total dose, 53.2 mg or approx 0.11 mg/kg) or sterile saline (0.9% NaCl) solution was injected adjacent to the medial and lateral palmar digital nerves at the level of the distal aspect of the proximal sesamoid bones of a randomly selected forelimb. Twenty-one days later, the opposite treatment was administered in the contralateral forelimb. A digital algometer was used to measure the mechanical nociceptive threshold (MNT) immediately before and at predetermined times for 48 hours after injection of each treatment. The mean MNT was compared between the 2 treatments at each measurement time. RESULTS The mean MNT for the liposomal bupivacaine-treated limbs was significantly greater (ie, the limb was less sensitive) than that for the saline-treated limbs between 30 minutes and 4 hours after treatment injection. Following liposomal bupivacaine administration, 1 horse developed mild swelling at the injection sites that resolved without treatment within 24 hours. No other adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that liposomal bupivacaine is another option for perineural anesthesia in horses. Further research is necessary to determine the optimal dose and better elucidate the duration of effect for the drug when used for palmar digital nerve blocks in horses.
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Seddighi R, Knych HK, Cox SK, Sun X, Moorhead KA, Doherty TJ. Evaluation of the sedative effects and pharmacokinetics of detomidine gel administered intravaginally to horses. Vet Anaesth Analg 2019; 46:772-779. [PMID: 31474339 DOI: 10.1016/j.vaa.2019.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 06/01/2019] [Accepted: 06/02/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To determine the sedative effects and pharmacokinetic profile of detomidine when administered intravaginally as a gel formulation to horses. STUDY DESIGN Randomized, crossover, masked experimental design. ANIMALS A group of six healthy adult mares (494 ± 56 kg). METHODS Mares were studied on two occasions and were administered either detomidine hydrochloride (10 μg kg-1) intravenously (treatment IV) or detomidine gel (40 μg kg-1) intravaginally (treatment IVG), separated by 1 week. Sedation, ataxia, muzzle-floor distance and heart rate (HR) were evaluated every 15 minutes for 240 minutes. Venous blood samples were collected at 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360 minutes postadministration and were analyzed for detomidine and metabolites using liquid chromatography-tandem mass spectrometry. Measured variables were compared over time and between treatments using mixed model analysis. Correlation between drug plasma concentrations and muzzle-floor distance, and sedation and ataxia scores was determined using the Spearman correlation coefficient. Data are presented as mean ± standard error of the mean and p value was set at <0.05. RESULTS Sedation was shorter with IV (119 ± 16 minutes) than with IVG (188 ± 22 minutes). Ataxia scores remained greater than baseline for 90 and 135 minutes for treatments IV and IVG, respectively. HR was lower than baseline for 45 and 30 minutes for IV and IVG, respectively, but did not differ between treatments. The mean maximum plasma concentration of detomidine, time to maximum concentration and bioavailability for treatment IVG was 8.57 ng mL-1, 0.37 hour and 25%, respectively. There was a significant correlation (r = 0.68) between plasma detomidine concentrations and sedation score. CONCLUSIONS AND CLINICAL RELEVANCE Detomidine gel administered intravaginally resulted in clinically important sedation and is a viable method for detomidine gel delivery in mares.
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Affiliation(s)
- Reza Seddighi
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.
| | - Heather K Knych
- K. L. Maddy Equine Analytical Chemistry Laboratory, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Sherry K Cox
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
| | - Xiaocun Sun
- Office of Information Technology, University of Tennessee, Knoxville, TN, USA
| | - Kaitlin A Moorhead
- College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
| | - Thomas J Doherty
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
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Bennett KJ, Seddighi R, Moorhead KA, Messenger K, Cox SK, Sun X, Pasloske K, Pypendop BH, Doherty TJ. Effect of fentanyl on the induction dose and minimum infusion rate of alfaxalone preventing movement in dogs. Vet Anaesth Analg 2019; 46:173-181. [DOI: 10.1016/j.vaa.2018.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/25/2018] [Accepted: 10/25/2018] [Indexed: 11/29/2022]
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Bray NW, Doherty TJ, Montero-Odasso M. The Effect of High Dose Vitamin D3 on Physical Performance in Frail Older Adults. A Feasibility Study. J Frailty Aging 2018; 7:155-161. [PMID: 30095145 DOI: 10.14283/jfa.2018.18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Vitamin D deficiency is ubiquitous in frailty but the effectiveness of vitamin D supplementation to improve outcomes in frail individuals is unclear. It has been postulated that higher than the current recommended doses (800 IU/day) may be needed to achieve a neuromuscular effect in frail individuals. OBJECTIVES 1) determine if 4000 IU per day of vitamin D3 is safe for frail older adults; and 2) establish the efficacy of this dose to improve physical performance outcomes in this population. DESIGN Open-label, feasibility study. SETTING Community retirement centre. PARTICIPANTS 40 older adults with frail or pre-frail characteristics. INTERVENTION 4000 IU of vitamin D3 and 1200 mcg of calcium carbonate daily for four months. MEASUREMENTS Physical performance (grip strength, gait speed and short physical performance battery score), cognitive health and vitamin D and iPTH serum levels before and after the intervention. RESULTS Frail individuals improved short physical performance battery score (1.19, p = 0.005), fast gait speed (4.65, p = 0.066) and vitamin D levels (7.81, p = 0.011). Only frail females made a significant improvement in grip strength (1.92, p = 0.003). Stratifying the sample by baseline vitamin D levels revealed that participants with vitamin D insufficiency (≤ 75 nmol/L) significantly improved short physical performance battery score (1.06, p = 0.04), fast gait speed (6.28, p = 0.004) and vitamin D levels (25.73, p = <0.0001). Pre-frail individuals, as well as those with sufficient vitamin D levels (> 75 nmol/L) made no significant improvement in any outcome. CONCLUSIONS Vitamin D supplementation using 4000 IU/daily is safe and has a modest beneficial effect on physical performance for frail individuals and those with insufficient vitamin D levels. Participants with vitamin D insufficiency (≤ 75 nmol/L) showed greater benefits. Our feasibility study provides results to help calculate effect size for a future RCT.
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Affiliation(s)
- N W Bray
- Dr. Manuel Montero-Odasso, Gait and Brain Lab, Parkwood Institute, 550 Wellington Road, Room A3-116, London, ON, Canada, N6C 0A7,E-mail: , Fax: (519) 685 0493
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Everett JB, Schumacher J, Doherty TJ, Black RA, Amelse LL, Krawczel P, Coetzee JF, Whitlock BK. Effects of stacked wedge pads and chains applied to the forefeet of Tennessee Walking Horses for a five-day period on behavioral and biochemical indicators of pain, stress, and inflammation. Am J Vet Res 2017; 79:21-32. [PMID: 29287151 DOI: 10.2460/ajvr.79.1.21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of stacked wedge pads and chains applied to the forefeet of Tennessee Walking Horses on behavioral and biochemical indicators of pain, stress, and inflamation. ANIMALS 20 Tennessee Walking Horses. PROCEDURES Horses were randomly assigned to 2 treatment groups: keg shoes (control; n = 10) or stacked wedge pads and exercise with chains (10). Ten days before treatment application, an accelerometer was attached at the left metatarsus of each horse to record daily activity. Horses were exercised for 20 minutes daily, beginning on day -7. On day 0, exercise ceased, the forefeet were trimmed, and the assigned treatment was applied. From days 1 through 5, horses were exercised as before. Blood samples for measurement of plasma cortisol, substance P, and fibrinogen concentrations were collected on days -5, 1, and 5 before and after exercise and every 30 minutes thereafter for 6 hours. RESULTS No significant differences in plasma concentrations of cortisol, substance P, and fibrinogen were detected between groups. Although lying behaviors changed after shoes were applied, these behaviors did not differ significantly between groups. Shoeing appeared to have altered behavior to a greater extent than did the type of treatment applied. CONCLUSIONS AND CLINICAL RELEVANCE Application of stacked wedge pads and chains to the forefeet of horses for a 5-day period as performed in this study evoked no acute or subacute stress or nociceptive response as measured. Although these findings should not be extrapolated to the long-term use of such devices in Tennessee Walking Horses performing the running walk, the data should be considered when making evidence-based decisions relating to animal welfare and the use of stacked wedge pads and chains.
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Clark-Price SC, Lascola KM, Carter JE, da Cunha AF, Donaldson LL, Doherty TJ, Martin-Flores M, Hofmeister EH, Keating SCJ, Mama KR, Mason DE, Posner LP, Sano H, Seddighi R, Shih AC, Weil AB, Schaeffer DJ. Assessment of agreement among diplomates of the American College of Veterinary Anesthesia and Analgesia for scoring the recovery of horses from anesthesia by use of subjective grading scales and development of a system for evaluation of the recovery of horses from anesthesia by use of accelerometry. Am J Vet Res 2017; 78:668-676. [PMID: 28541154 DOI: 10.2460/ajvr.78.6.668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate agreement among diplomates of the American College of Veterinary Anesthesia and Analgesia for scores determined by use of a simple descriptive scale (SDS) or a composite grading scale (CGS) for quality of recovery of horses from anesthesia and to investigate use of 3-axis accelerometry (3AA) for objective evaluation of recovery. ANIMALS 12 healthy adult horses. PROCEDURES Horses were fitted with a 3AA device and then were anesthetized. Eight diplomates evaluated recovery by use of an SDS, and 7 other diplomates evaluated recovery by use of a CGS. Agreement was tested with κ and AC1 statistics for the SDS and an ANOVA for the CGS. A library of mathematical models was used to map 3AA data against CGS scores. RESULTS Agreement among diplomates using the SDS was slight (κ = 0.19; AC1 = 0.22). The CGS scores differed significantly among diplomates. Best fit of 3AA data against CGS scores yielded the following equation: RS = 9.998 × SG0.633 × ∑UG0.174, where RS is a horse's recovery score determined with 3AA, SG is acceleration of the successful attempt to stand, and ∑UG is the sum of accelerations of unsuccessful attempts to stand. CONCLUSIONS AND CLINICAL RELEVANCE Subjective scoring of recovery of horses from anesthesia resulted in poor agreement among diplomates. Subjective scoring may lead to differences in conclusions about recovery quality; thus, there is a need for an objective scoring method. The 3AA system removed subjective bias in evaluations of recovery of horses and warrants further study.
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Smith CK, Seddighi R, Cox SK, Sun X, Knych HK, Doherty TJ. Effect of dexmedetomidine on the minimum infusion rate of propofol preventing movement in dogs. Vet Anaesth Analg 2017; 44:1287-1295. [PMID: 29074303 DOI: 10.1016/j.vaa.2017.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/17/2017] [Accepted: 07/19/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine the effect of dexmedetomidine on induction dose and minimum infusion rate of propofol preventing movement (MIRNM). STUDY DESIGN Randomized crossover, unmasked, experimental design. ANIMALS Three male and three female healthy Beagle dogs weighing 10.2 ± 2.8 kg. METHODS Dogs were studied on three occasions at weekly intervals. Premedications were 0.9% saline (treatment P) or dexmedetomidine (1 μg kg-1, treatment PLD; 2 μg kg-1, treatment PHD) intravenously. Anesthesia was induced with propofol (2 mg kg-1 and then 1 mg kg-1 every 15 seconds) until intubation. Anesthesia was maintained for 90 minutes in P with propofol (0.5 mg kg-1 minute-1) and saline, in PLD with propofol (0.35 mg kg-1 minute-1) and dexmedetomidine (1 μg kg-1 hour-1), and in PHD with propofol (0.3 mg kg-1 minute-1) and dexmedetomidine (2 μg kg-1 hour-1). The stimulus (50 V, 50 Hz, 10 ms) was applied to the antebrachium, and propofol infusion was increased or decreased by 0.025 mg kg-1 minute-1 based on a positive or negative response, respectively. Data were analyzed using a mixed-model anova and presented as mean ± standard error. RESULTS Propofol induction doses were 8.68 ± 0.57 (P), 6.13 ± 0.67 (PLD) and 4.78 ± 0.39 (PHD) mg kg-1 and differed among treatments (p < 0.05). Propofol MIRNM values were 0.68 ± 0.13, 0.49 ± 0.16 and 0.26 ± 0.05 mg kg-1 minute-1 for P, PLD and PHD, respectively. Propofol MIRNM decreased 59% in PHD (p < 0.05). Plasma propofol concentrations were 14.04 ± 2.30 (P), 11.30 ± 4.30 (PLD) and 7.96 ± 0.72 (PHD) μg mL-1 and dexmedetomidine concentrations were 0.68 ± 0.12 (PLD) and 0.89 ± 0.08 (PHD) ng mL-1 at MIRNM determination. CONCLUSIONS AND CLINICAL RELEVANCE Dexmedetomidine (1 and 2 μg kg-1) decreased propofol induction dose. Dexmedetomidine (2 μg kg-1 hour-1) resulted in a significant decrease in propofol MIRNM.
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Affiliation(s)
- Christopher K Smith
- Department of Small Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA.
| | - Reza Seddighi
- Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA
| | - Sherry K Cox
- Department of Biological and Diagnostic Sciences, University of Tennessee, Knoxville, TN, USA
| | - Xiaocun Sun
- Office of Information and Technology, University of Tennessee, Knoxville, TN, USA
| | - Heather K Knych
- KL Maddy Equine Analytical Chemistry Laboratory, University of California Davis, Davis, CA, USA
| | - Thomas J Doherty
- Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA
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Simon BT, Scallan EM, O O, Ebner LS, Cerullo MN, Follette C, Cox SK, Doherty TJ, Lizarraga I. Pharmacokinetics and pharmacodynamics of midazolam following intravenous and intramuscular administration to sheep. Am J Vet Res 2017; 78:539-549. [DOI: 10.2460/ajvr.78.5.539] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Suarez MA, Seddighi R, Egger CM, Rohrbach BW, Cox SK, KuKanich BK, Doherty TJ. Effect of fentanyl and lidocaine on the end-tidal sevoflurane concentration preventing motor movement in dogs. Am J Vet Res 2017; 78:12-16. [PMID: 28029285 DOI: 10.2460/ajvr.78.1.12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine effects of fentanyl, lidocaine, and a fentanyl-lidocaine combination on the minimum alveolar concentration of sevoflurane preventing motor movement (MACNM) in dogs. ANIMALS 6 adult Beagles. PROCEDURES Dogs were anesthetized with sevoflurane in oxygen 3 times (1-week intervals). Baseline MACNM (MACNM-B) was determined starting 45 minutes after induction of anesthesia. Dogs then received 1 of 3 treatments IV: fentanyl (loading dose, 15 μg/kg; constant rate infusion [CRI], 6 μg/kg/h), lidocaine (loading dose, 2 mg/kg; CRI, 6 mg/kg/h), and the fentanyl-lidocaine combination at the same doses. Determination of treatment MACNM (MACNM-T) was initiated 90 minutes after start of the CRI. Venous blood samples were collected at the time of each treatment MACNM measurement for determination of plasma concentrations of fentanyl and lidocaine. RESULTS Mean ± SEM overall MACNM-B for the 3 treatments was 2.70 ± 0.27 vol%. The MACNM decreased from MACNM-B to MACNM-T by 39%, 21%, and 55% for fentanyl, lidocaine, and the fentanyl-lidocaine combination, respectively. This decrease differed significantly among treatments. Plasma fentanyl concentration was 3.25 and 2.94 ng/mL for fentanyl and the fentanyl-lidocaine combination, respectively. Plasma lidocaine concentration was 2,570 and 2,417 ng/mL for lidocaine and the fentanyl-lidocaine combination, respectively. Plasma fentanyl and lidocaine concentrations did not differ significantly between fentanyl and the fentanyl-lidocaine combination or between lidocaine and the fentanyl-lidocaine combination. CONCLUSIONS AND CLINICAL RELEVANCE CRIs of fentanyl, lidocaine, and the fentanyl-lidocaine combination at the doses used were associated with clinically important and significant decreases in the MACNM of sevoflurane in dogs.
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Davis CA, Seddighi R, Cox SK, Sun X, Egger CM, Doherty TJ. Effect of fentanyl on the induction dose and minimum infusion rate of propofol preventing movement in dogs. Vet Anaesth Analg 2017. [PMID: 28624496 DOI: 10.1016/j.vaa.2016.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To determine the effect of fentanyl on the induction dose of propofol and minimum infusion rate required to prevent movement in response to noxious stimulation (MIRNM) in dogs. STUDY DESIGN Crossover experimental design. ANIMALS Six healthy, adult intact male Beagle dogs, mean±standard deviation 12.6±0.4 kg. METHODS Dogs were administered 0.9% saline (treatment P), fentanyl (5 μg kg-1) (treatment PLDF) or fentanyl (10 μg kg-1) (treatment PHDF) intravenously over 5 minutes. Five minutes later, anesthesia was induced with propofol (2 mg kg-1, followed by 1 mg kg-1 every 15 seconds to achieve intubation) and maintained for 90 minutes by constant rate infusions (CRIs) of propofol alone or with fentanyl: P, propofol (0.5 mg kg-1 minute-1); PLDF, propofol (0.35 mg kg-1 minute-1) and fentanyl (0.1 μg kg-1 minute-1); PHDF, propofol (0.3 mg kg-1 minute-1) and fentanyl (0.2 μg kg-1 minute-1). Propofol CRI was increased or decreased based on the response to stimulation (50 V, 50 Hz, 10 mA), with 20 minutes between adjustments. Data were analyzed using a mixed-model anova and presented as mean±standard error. RESULTS ropofol induction doses were 6.16±0.31, 3.67±0.21 and 3.33±0.42 mg kg-1 for P, PLDF and PHDF, respectively. Doses for PLDF and PHDF were significantly decreased from P (p<0.05) but not different between treatments. Propofol MIRNM was 0.60±0.04, 0.29±0.02 and 0.22±0.02 mg kg-1 minute-1 for P, PLDF and PHDF, respectively. MIRNM in PLDF and PHDF was significantly decreased from P. MIRNM in PLDF and PHDF were not different, but their respective percent decreases of 51±3 and 63±2% differed (p=0.035). CONCLUSIONS AND CLINICAL RELEVANCE Fentanyl, at the doses studied, caused statistically significant and clinically important decreases in the propofol induction dose and MIRNM.
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Affiliation(s)
- Carrie A Davis
- Department of Small Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA.
| | - Reza Seddighi
- Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA
| | - Sherry K Cox
- Department of Biological and Diagnostic Sciences, University of Tennessee, Knoxville, TN, USA
| | - Xiaocun Sun
- Office of Information and Technology, University of Tennessee, Knoxville, TN, USA
| | - Christine M Egger
- Department of Small Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA
| | - Thomas J Doherty
- Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville, TN, USA
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Seddighi R, Odoi A, Doherty TJ. Effect of dexmedetomidine hydrochloride on tiletamine hydrochloride–zolazepam hydrochloride anesthesia in alpacas. Am J Vet Res 2016; 77:1057-63. [DOI: 10.2460/ajvr.77.10.1057] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Reed RA, Seddighi MR, Odoi A, Cox SK, Egger CM, Doherty TJ. Effect of ketamine on the minimum infusion rate of propofol needed to prevent motor movement in dogs. Am J Vet Res 2016; 76:1022-30. [PMID: 26618726 DOI: 10.2460/ajvr.76.12.1022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the minimum infusion rate (MIR) of propofol required to prevent movement in response to a noxious stimulus in dogs anesthetized with propofol alone or propofol in combination with a constant rate infusion (CRI) of ketamine. ANIMALS 6 male Beagles. PROCEDURES Dogs were anesthetized on 3 occasions, at weekly intervals, with propofol alone (loading dose, 6 mg/kg; initial CRI, 0.45 mg/kg/min), propofol (loading dose, 5 mg/kg; initial CRI, 0.35 mg/kg/min) and a low dose of ketamine (loading dose, 2 mg/kg; CRI, 0.025 mg/kg/min), or propofol (loading dose, 4 mg/kg; initial CRI, 0.3 mg/kg/min) and a high dose of ketamine (loading dose, 3 mg/kg; CRI, 0.05 mg/kg/min). After 60 minutes, the propofol MIR required to prevent movement in response to a noxious electrical stimulus was determined in duplicate. RESULTS Least squares mean ± SEM propofol MIRs required to prevent movement in response to the noxious stimulus were 0.76 ± 0.1 mg/kg/min, 0.60 ± 0.1 mg/kg/min, and 0.41 ± 0.1 mg/kg/min when dogs were anesthetized with propofol alone, propofol and low-dose ketamine, and propofol and high-dose ketamine, respectively. There were significant decreases in the propofol MIR required to prevent movement in response to the noxious stimulus when dogs were anesthetized with propofol and low-dose ketamine (27 ± 10%) or with propofol and high-dose ketamine (30 ± 10%). CONCLUSIONS AND CLINICAL RELEVANCE Ketamine, at the doses studied, significantly decreased the propofol MIR required to prevent movement in response to a noxious stimulus in dogs.
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Johnson AN, Seddighi R, Rohrbach BW, Cox SK, Egger CM, Martin-Flores M, Doherty TJ. Effects of magnesium sulfate and propofol on the minimum alveolar concentration preventing motor movement in sevoflurane-anesthetized dogs. Am J Vet Res 2016; 77:575-81. [PMID: 27227494 DOI: 10.2460/ajvr.77.6.575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To evaluate the effect of MgSO4, alone and in combination with propofol, on the minimum alveolar concentration preventing motor movement (MACNM) in sevoflurane-anesthetized dogs. ANIMALS 6 healthy purpose-bred adult male Beagles (least squares mean ± SEM body weight, 12.0 ± 1.1 kg). PROCEDURES Dogs were anesthetized 3 times at weekly intervals. The MACNM was measured 45 minutes after induction of anesthesia (baseline; MACNM-B) and was determined each time by use of a noxious electrical stimulus. Treatments were administered as a loading dose and constant rate infusion (CRI) as follows: treatment 1, MgSO4 loading dose of 45 mg/kg and CRI of 15 mg/kg/h; treatment 2, propofol loading dose of 4 mg/kg and CRI of 9 mg/kg/h; and treatment 3, MgSO4 and propofol combination (same doses used previously for each drug). A mixed-model ANOVA and Tukey-Kramer tests were used to determine effects of each treatment on the percentage decrease from MACNM-B. Data were reported as least squares mean ± SEM values. RESULTS Decrease from MACNM-B was 3.4 ± 3.1%, 48.3 ± 3.1%, and 50.3 ± 3.1%, for treatments 1, 2, and 3, respectively. The decrease for treatments 2 and 3 was significantly different from that for treatment 1; however, no significant difference existed between results for treatments 2 and 3. CONCLUSIONS AND CLINICAL RELEVANCE MgSO4 did not affect MACNM, nor did it potentiate the effects of propofol on MACNM. Administration of MgSO4 in this study appeared to provide no clinical advantage as an anesthetic adjuvant.
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Queiroz-Williams P, Doherty TJ, da Cunha AF, Leonardi C. Effects of ketamine and lidocaine in combination on the sevoflurane minimum alveolar concentration in alpacas. Can J Vet Res 2016; 80:141-145. [PMID: 27127341 PMCID: PMC4836040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 11/04/2015] [Indexed: 06/05/2023]
Abstract
This study investigated the effects of ketamine and lidocaine in combination on the minimum alveolar concentration of sevoflurane (MACSEVO) in alpacas. Eight healthy, intact male, adult alpacas were studied on 2 separate occasions. Anesthesia was induced with SEVO, and baseline MAC (MACB) determination began 45 min after induction. After MACB determination, alpacas were randomly given either an intravenous (IV) loading dose (LD) and infusion of saline or a loading dose [ketamine = 0.5 mg/kg body weight (BW); lidocaine = 2 mg/kg BW] and an infusion of ketamine (25 μg/kg BW per minute) in combination with lidocaine (50 μg/kg BW per minute), and MACSEVO was re-determined (MACT). Quality of recovery, time-to-extubation, and time-to-standing, were also evaluated. Mean MACB was 1.88% ± 0.13% and 1.89% ± 0.14% for the saline and ketamine + lidocaine groups, respectively. Ketamine and lidocaine administration decreased (P < 0.05) MACB by 57% and mean MACT was 0.83% ± 0.10%. Saline administration did not change MACB. Time to determine MACB and MACT was not significantly different between the treatments. The quality of recovery, time-to-extubation, and time-to-standing, were not different between groups. The infusion of ketamine combined with lidocaine significantly decreased MACSEVO by 57% and did not adversely affect time-to-standing or quality of recovery.
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MESH Headings
- Anesthesia, Inhalation/veterinary
- Anesthetics, Dissociative/administration & dosage
- Anesthetics, Dissociative/pharmacokinetics
- Anesthetics, Dissociative/pharmacology
- Anesthetics, Inhalation/administration & dosage
- Anesthetics, Inhalation/pharmacology
- Anesthetics, Local/administration & dosage
- Anesthetics, Local/pharmacokinetics
- Anesthetics, Local/pharmacology
- Animals
- Camelids, New World
- Cross-Over Studies
- Drug Interactions
- Ketamine/administration & dosage
- Ketamine/pharmacokinetics
- Ketamine/pharmacology
- Lidocaine/administration & dosage
- Lidocaine/pharmacokinetics
- Lidocaine/pharmacology
- Male
- Methyl Ethers/administration & dosage
- Methyl Ethers/pharmacokinetics
- Methyl Ethers/pharmacology
- Pulmonary Alveoli/metabolism
- Sevoflurane
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Affiliation(s)
- Patricia Queiroz-Williams
- Address all correspondence to Dr. Patricia Queiroz-Williams; telephone: 225-578-9600; fax: 225-578-9559; e-mail:
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Singsank-Coats J, Seddighi R, Rohrbach BW, Cox SK, Egger CM, Doherty TJ. The anesthetic interaction of propofol and sevoflurane on the minimum alveolar concentration preventing motor movement (MACNM) in dogs. Can J Vet Res 2015; 79:95-100. [PMID: 25852224 PMCID: PMC4365712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 07/11/2014] [Indexed: 06/04/2023]
Abstract
The objective of this study was to determine the effects of propofol on the minimum alveolar concentration of sevoflurane needed to prevent motor movement (MAC(NM)) in dogs subjected to a noxious stimulus using randomized crossover design. Six, healthy, adult beagles (9.2 ± 1.3 kg) were used. Dogs were anesthetized with sevoflurane on 3 occasions, at weekly intervals, and baseline MAC(NM) (MAC(NM-B)) was determined on each occasion. Propofol treatments were administered as loading dose (LD) and constant rate infusion (CRI) as follows: Treatment 1 (T1) was 2 mg/kg body weight (BW) and 4.5 mg/kg BW per hour; T2 was 4 mg/kg BW and 9 mg/kg BW per hour; T3 was 8 mg/kg BW and 18 mg/kg BW per hour, respectively. Treatment MAC(NM) (MAC(NM-T)) determination was initiated 60 min after the start of the CRI. Two venous blood samples were collected and combined at each MAC(NM-T) determination for measurement of blood propofol concentration using high-performance liquid chromatography method (HPLC). Data were analyzed using a mixed-model ANOVA and are presented as least square means (LSM) ± standard error of means (SEM). Propofol infusions in the range of 4.5 to 18 mg/kg BW per hour resulted in mean blood concentrations between 1.3 and 4.4 μg/mL, and decreased (P < 0.05) sevoflurane MAC(NM) in a concentration-dependent manner. The percentage decrease in MAC(NM) was 20.5%, 43.0%, and 68.3%, with corresponding blood propofol concentrations of 1.3 ± 0.3 μg/mL, 2.5 ± 0.3 μg/mL, and 4.4 ± 0.3 μg/mL, for T1, T2, and T3, respectively. Venous blood propofol concentrations were strongly correlated (r = 0.855, P < 0.0001) with the decrease in MAC(NM). In dogs, propofol decreased the sevoflurane MAC(NM) in a concentration-dependent manner.
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Affiliation(s)
| | - Reza Seddighi
- Address all correspondence to Dr. Reza Seddighi; telephone: (865) 974-8387; fax: (865) 974-5773; e-mail:
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Seddighi R, Doherty TJ, Kukanich B, Egger CM, Henn MA, Long WM, Rohrbach BW. The interaction of nitrous oxide and fentanyl on the minimum alveolar concentration of sevoflurane blocking motor movement (MACNM) in dogs. Can J Vet Res 2014; 78:202-206. [PMID: 24982551 PMCID: PMC4068411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 07/22/2013] [Indexed: 06/03/2023]
Abstract
The study objective was to determine the effects of 70% nitrous oxide (N2O) and fentanyl on the end-tidal concentration of sevoflurane necessary to prevent movement (MACNM) in response to noxious stimulation in dogs. Six healthy, adult, intact male, mixed-breed dogs were used on 3 occasions in a randomized crossover design. After induction of anesthesia with sevoflurane, each of the following treatments was randomly administered: fentanyl loading dose (Ld) of 15 μg/kg and infusion of 6 μg/kg per hour [treatment 1 (T1)], 70% N2O (T2), or fentanyl (Ld of 15 μg/kg and infusion of 6 μg/kg per hour) combined with 70% N2O (T3). Each dog received each of the 3 treatments once during the 3-week period. Determination of MACNM was initiated 90 min after the start of each treatment. The values were compared using the baseline MACNM, which had been determined in a previous study on the same group of dogs. Data were analyzed using a mixed-model analysis of variance (ANOVA) and Tukey-Kramer tests, and expressed as least squares mean ± SEM. The baseline MACNM decreased by 36.6 ± 4.0%, 15.0 ± 4.0%, and 46.0 ± 4.0% for T1, T2, and T3, respectively (P < 0.05), and differed (P < 0.05) among treatments. Mean fentanyl plasma concentrations did not differ (P ≥ 0.05) between T1 (3.70 ± 0.56 ng/mL) and T3 (3.50 ± 0.56 ng/mL). The combination of fentanyl and N2O resulted in a greater sevoflurane MACNM sparing effect than either treatment alone.
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Affiliation(s)
- Reza Seddighi
- Address all correspondence to Dr. Reza Seddighi; telephone: (865) 974-8387; fax: (865) 974-5773; e-mail:
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Seddighi R, Elliot SB, Whitlock BK, Egger CM, Doherty TJ. Antinociceptive and selected physiological effects of morphine and xylazine on tiletamine-zolazepam anesthesia in llamas. Vet Anaesth Analg 2014; 41:365-71. [DOI: 10.1111/vaa.12128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 09/12/2013] [Indexed: 11/29/2022]
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Affiliation(s)
- Rebecca Macy
- Lewis & Clark Graduate School of Counseling, Portland, Oregon
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Voulgaris DA, Egger CM, Seddighi MR, Rohrbach BW, Love LC, Doherty TJ. The effect of nitrous oxide on the minimum alveolar concentration (MAC) and MAC derivatives of isoflurane in dogs. Can J Vet Res 2013; 77:131-135. [PMID: 24082405 PMCID: PMC3605929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/15/2012] [Indexed: 06/02/2023]
Abstract
This study investigated the effects of 70% nitrous oxide (N2O) on the minimum alveolar concentration (MAC) of isoflurane (ISO) that prevents purposeful movement, the MAC of ISO at which there is no motor movement (MACNM), and the MAC of ISO at which autonomic responses are blocked (MACBAR) in dogs. Six adult, healthy, mixed-breed, intact male dogs were anesthetized with ISO delivered via mask. Baseline MAC, MACNM, and MACBAR of ISO were determined for each dog using a supra-maximal electrical stimulus (50 V, 50 Hz, 10 ms). Nitrous oxide (70%) was then administered and MAC and its derivatives (N2O-MAC, N2O-MACNM, and N2O-MACBAR) were determined using the same methodology. The values for baseline MAC, MACNM, and MACBAR were 1.39 ± 0.14, 1.59 ± 0.10, and 1.72 ± 0.16, respectively. The addition of 70% N2O decreased MAC, MACNM, and MACBAR by 32%, 15%, and 25%, respectively.
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Affiliation(s)
| | - Christine M. Egger
- Address all correspondence to Dr. Christine M. Egger; telephone: (865) 974-8387; fax: (865) 974-5554; e-mail:
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Reilly S, Seddighi R, Egger CM, Rohrbach BW, Doherty TJ, Qu W, Johnson JR. The effect of fentanyl on the end-tidal sevoflurane concentration needed to prevent motor movement in dogs. Vet Anaesth Analg 2013; 40:290-6. [PMID: 23368842 DOI: 10.1111/vaa.12013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 02/03/2012] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The objectives of this study were to determine the effects of fentanyl on the end-tidal concentration of sevoflurane needed to prevent motor movement (MACNM ) in response to noxious stimulation, and to evaluate if acute tolerance develops. STUDY DESIGN Randomized cross-over experimental study. ANIMALS Six healthy, adult (2-3 years old), intact male, mixed-breed dogs weighing 16.2 ± 1.1 kg. METHODS Six dogs were randomly assigned to receive one of three separate treatments over a 3 week period. After baseline sevoflurane MACNM (MACNM-B) determination, fentanyl treatments (T) were administered as a loading dose (Ld) and constant rate infusion (CRI) as follows: T1-Ld of 7.5 μg kg(-1) and CRI at 3 μg kg(-1) hour(-1); T2-Ld of 15 μg kg(-1) and CRI at 6.0 μg kg (-1) hour(-1); T3-Ld of 30 μg kg(-1) and CRI at 12 μg kg(-1) hour(-1). The MACNM was defined as the minimum end-tidal sevoflurane concentration preventing motor movement. The first post-treatment MACNM (MACNM-I) determination was initiated 90 minutes after the start of the CRI, and a second MACNM (MACNM - II) determination was initiated 3 hours after MACNM-I was established. RESULTS The overall least square mean MACNM-B for all groups was 2.66%. All treatments decreased (p < 0.05) MACNM, and the decrease from baseline was 22%, 35% and 41% for T1, T2 and T3, respectively. Percentage change in T1 differed (p < 0.05) from T2 and T3; however, T2 did not differ from T3. MACNM-I was not significantly different from MACNM-II within treatments. CONCLUSIONS AND CLINICAL RELEVANCE Fentanyl doses in the range of 3-12 μg kg(-1) hour(-1) significantly decreased the sevoflurane MACNM. Clinically significant tolerance to fentanyl did not occur under the study conditions.
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Affiliation(s)
- Sabrina Reilly
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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Abstract
Advancements in veterinary medicine have resulted in an increased number of geriatric horses being presented for medical or surgical procedures that require general anesthesia. Due to the physiological changes associated with aging and the likelihood of concurrent disease conditions, the geriatric equine is at an increased risk during anesthesia. The main physiological changes associated with aging, and their impact on anesthesia, are discussed in this review.
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Affiliation(s)
- Reza Seddighi
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Veterinary Medical Center, University of Tennessee, Knoxville, TN, USA,
| | - Thomas J Doherty
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Veterinary Medical Center, University of Tennessee, Knoxville, TN, USA,
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Abstract
The purposes of this study were to determine 1) whether sex differences in quadriceps torque and isotonic power persist when controlling for muscle volume (i. e., torque/muscle volume and power/muscle volume) in participants with knee osteoarthritis (OA) and 2) the factors responsible for potential sex differences. Isometric torque, isotonic power (the product of torque and velocity, measured at 10, 20, 30, 40 and 50% maximal voluntary contraction; MVC) and maximal unloaded velocity were assessed in men (n=16, mean age=62.1 ± 7.2) and women (n=17, mean age=60.4 ± 4.3) with knee OA. Torque and power were normalized to muscle volume. The interpolated twitch technique was used to measure voluntary activation (VA) and evoked twitch and torque-frequency characteristics were measured to obtain information about muscle fibre distribution. Torque and power at all loads were significantly lower in women (p<0.05). Sex differences in power were reduced by 50% when controlling for muscle volume but were still significant at 10-40% MVC (p<0.05). No differences in VA, torque-frequency properties or time-to-peak tension of the evoked twitch were observed (p>0.05). These results suggest that only minor sex differences in torque and power persist when controlling for muscle volume. As VA and contractile property differences were not observed, other factors seem to be responsible.
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Affiliation(s)
- M J Berger
- Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada.
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Berger MJ, McKenzie CA, Chess DG, Goela A, Doherty TJ. Quadriceps neuromuscular function and self-reported functional ability in knee osteoarthritis. J Appl Physiol (1985) 2012; 113:255-62. [PMID: 22604883 DOI: 10.1152/japplphysiol.00947.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purposes of this study were to determine 1) the relationships of self-reported function scores in patients with knee osteoarthritis (OA) to both maximal isometric torque and to isotonic power at a variety of loads, and 2) the degree to which muscle volume (MV) or voluntary activation (VA) are associated with torque and power measures in this population. Isometric maximal voluntary contraction (MVC) torque and isotonic power [performed at loads corresponding to 10, 20, 30, 40, and 50% MVC, and a minimal load ("Zero Load")] were measured in 40 participants with knee OA. Functional ability was measured with the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function subscale. MV was determined with magnetic resonance imaging, and VA was measured with the interpolated twitch technique. In general, power measured at lower loads (Zero Load and 10-30% MVC, r(2) = 0.21-0.28, P < 0.05) predicted a greater proportion of the variance in function than MVC torque (r(2) = 0.18, P < 0.05), with power measured at Zero Load showing the strongest association (r(2) = 0. 28, P < 0.05). MV was the strongest predictor of MVC torque and power measures in multiple regression models (r(2) = 0.42-0.72). VA explained only 6% of the variance in MVC torque and was not significantly associated with power at any load (P > 0.05). Quadriceps MVC torque and power are associated with self-reported function in knee OA, but muscle power at lower loads is more predictive of function than MVC torque. The variance in MVC torque and power between participants is due predominantly to differences in MV and has little to do with deficits in VA.
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Affiliation(s)
- M J Berger
- Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
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Seddighi R, Egger CM, Rohrbach BW, Hobbs M, Doherty TJ. Effect of nitrous oxide on the minimum alveolar concentration for sevoflurane and the minimum alveolar concentration derivatives that prevent motor movement and autonomic responses in dogs. Am J Vet Res 2012; 73:341-5. [DOI: 10.2460/ajvr.73.3.341] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Swim JK, Stern PC, Doherty TJ, Clayton S, Reser JP, Weber EU, Gifford R, Howard GS. Psychology's contributions to understanding and addressing global climate change. ACTA ACUST UNITED AC 2011; 66:241-50. [PMID: 21553950 DOI: 10.1037/a0023220] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Global climate change poses one of the greatest challenges facing humanity in this century. This article, which introduces the American Psychologist special issue on global climate change, follows from the report of the American Psychological Association Task Force on the Interface Between Psychology and Global Climate Change. In this article, we place psychological dimensions of climate change within the broader context of human dimensions of climate change by addressing (a) human causes of, consequences of, and responses (adaptation and mitigation) to climate change and (b) the links between these aspects of climate change and cognitive, affective, motivational, interpersonal, and organizational responses and processes. Characteristics of psychology that cross content domains and that make the field well suited for providing an understanding of climate change and addressing its challenges are highlighted. We also consider ethical imperatives for psychologists' involvement and provide suggestions for ways to increase psychologists' contribution to the science of climate change.
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Affiliation(s)
- Janet K Swim
- Department of Psychology, Pennsylvania State University, University Park, PA 16802-3106, USA.
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Seddighi R, Egger CM, Rohrbach BW, Cox SK, Doherty TJ. The effect of midazolam on the end-tidal concentration of isoflurane necessary to prevent movement in dogs. Vet Anaesth Analg 2011; 38:195-202. [PMID: 21492384 DOI: 10.1111/j.1467-2995.2011.00615.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine the possible additive effect of midazolam, a GABA(A) agonist, on the end-tidal concentration of isoflurane that prevents movement (MAC(NM) ) in response to noxious stimulation. STUDY DESIGN Randomized cross-over experimental study. ANIMALS Six healthy, adult intact male, mixed-breed dogs. METHODS After baseline isoflurane MAC(NM) (MAC(NM-B) ) determination, midazolam was administered as a low (LDS), medium (MDS) or high (HDS) dose series of midazolam. Each series consisted of two dose levels, low and high. The LDS was a loading dose (Ld) of 0.2 mg kg(-1) and constant rate infusion (CRI) (2.5 μg kg(-1) minute(-1)) (LDL), followed by an Ld (0.4 mg kg(-1)) and CRI (5 μg kg(-1) minute(-1)) (LDH). The MDS was an Ld (0.8 mg kg(-1)) and CRI (10 μg kg(-1) minute(-1)) (MDL) followed by an Ld (1.6 mg kg(-1)) and CRI (20 μg kg(-1) minute(-1)) (MDH). The HDS was an Ld (3.2 mg kg(-1)) and CRI (40 μg kg(-1) minute(-1)) (HDL) followed by an Ld (6.4 mg kg(-1)) and CRI (80 μg kg(-1) minute(-1)) (HDH). MAC(NM) was re-determined after each dose in each series (MAC(NM-T)). RESULTS The median MAC(NM-B) was 1.42. MAC(NM-B) did not differ among groups (p > 0.05). Percentage reduction in MAC(NM) was significantly less in the LDS (11 ± 5%) compared with MDS (30 ± 5%) and HDS (32 ± 5%). There was a weak correlation between the plasma midazolam concentration and percentage MAC(NM) reduction (r = 0.36). CONCLUSION AND CLINICAL RELEVANCE Midazolam doses in the range of 10-80 μg kg(-1) minute(-1) significantly reduced the isoflurane MAC(NM) . However, doses greater than 10 μg kg(-1) minute(-1) did not further decrease MAC(NM) indicating a ceiling effect.
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Affiliation(s)
- Reza Seddighi
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
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Abstract
Clinicians who use electromyographic (EMG) signals to help determine the presence or absence of abnormality in a muscle often, with varying degrees of success, evaluate sets of motor unit potentials (MUPs) qualitatively and/or quantitatively to characterize the muscle in a clinically meaningful way. The resulting muscle characterization can be improved using automated analysis. As such, the intent of this study was to evaluate the performance of automated, conventional Means/Outlier and Probabilistic methods in converting MUP statistics into a concise, and clinically relevant, muscle characterization. Probabilistic methods combine the set of MUP characterizations, derived using Pattern Discovery (PD), of all MUPs detected from a muscle into a characterization measure that indicates normality or abnormality. Using MUP data from healthy control subjects and patients with known neuropathic disorders, a Probabilistic method that used Bayes' rule to combine MUP characterizations into a Bayesian muscle characterization (BMC) achieved a categorization accuracy of 79.7% compared to 76.4% using the Mean method (P > 0.1) for biceps muscles and 94.6% accuracy for the BMC method compared to 85.8% using the Mean method (P < 0.01) for first dorsal interosseous muscles. The BMC method can facilitate the determination of "possible," "probable," or "definite" levels for a given muscle categorization (e.g., neuropathic) whereas the conventional Means and Outlier methods support only a dichotomous "normal" or "abnormal" decision. This work demonstrates that the BMC method can provide information that may be more useful in supporting clinical decisions than that provided by the conventional Means or Outlier methods.
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Affiliation(s)
- L J Pino
- Systems Design Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.
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Valverde A, Gunkelt C, Doherty TJ, Giguère S, Pollak AS. Effect of a constant rate infusion of lidocaine on the quality of recovery from sevoflurane or isoflurane general anaesthesia in horses. Equine Vet J 2010; 37:559-64. [PMID: 16295936 DOI: 10.2746/042516405775314772] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Lidocaine constant rate infusions (CRIs) are common as an intraoperative adjunct to general anaesthesia, but their influence on quality of recovery has not been thoroughly determined. OBJECTIVES To determine the effects of an intraoperative i.v. CRI of lidocaine on the quality of recovery from isoflurane or sevoflurane anaesthesia in horses undergoing various surgical procedures, using a modified recovery score system. HYPOTHESIS The administration of intraoperative lidocaine CRI decreases the quality of recovery in horses. METHODS Lidocaine (2 mg/kg bwt bolus followed by 50 microg/kg bwt/min) or saline was administered for the duration of surgery or until 30 mins before the end of surgery under isoflurane (n = 27) and sevoflurane (n = 27). RESULTS Horses receiving lidocaine until the end of surgery had a significantly higher degree of ataxia and a tendency towards significance for a lower quality of recovery. There was no correlation between lidocaine plasma concentrations at recovery and the quality of recovery. CONCLUSIONS Intraoperative CRI of lidocaine affects the degree of ataxia and may decrease the quality of recovery. POTENTIAL RELEVANCE Discontinuing lidocaine CRI 30 mins before the end of surgery is recommended to reduce ataxia during the recovery period.
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Affiliation(s)
- A Valverde
- Department of Large Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA
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Abstract
REASONS FOR PERFORMING STUDY Commonly used analgesics (nonsteroidal anti-inflammatory agents, opioids and alpha2-agonists) have unwanted side effects. An effective alternative with minimal adverse effects would benefit clinical equine pain management. OBJECTIVES To compare the effect of lidocaine or saline on duodenal and rectal distension threshold pressure and somatic thermal threshold in conscious mature horses. HYPOTHESIS Systemically administered lidocaine would increase somatic and visceral nociceptive thresholds. METHODS Lidocaine (2 mg/kg bwt bolus followed by 50 microg/kg bwt/min for 2 h) or saline was administered to 6 horses each carrying a permanently implanted gastric cannula, in a randomised, blinded cross-over design. Thermal threshold was measured using a probe containing a heater element placed over the withers which supplied heat until the horse responded. A barostatically controlled intraduodenal balloon was distended until a discomfort response was obtained. A rectal balloon was inflated until extruded or signs of discomfort noted. RESULTS Thermal threshold was increased significantly 30 and 90 mins after the start of lidocaine infusion. There was no change in duodenal distension pressure and a small but clinically insignificant change in colorectal distension pressure in the lidocaine group. CONCLUSIONS At the dose used, systemically administered lidocaine produced thermal antinociception but minimal changes in visceral nociception. POTENTIAL RELEVANCE At these doses, lidocaine may play a role in somatic analgesia in horses.
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Affiliation(s)
- S A Robertson
- Island Whirl Equine Colic Research Laboratory, Department of Large Animal Clinical Sciences, University of Florida, College of Veterinary Medicine, Gainesville, Florida 32610-0136, USA
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Abstract
Surgical manipulation of the intestines activates intestinal macrophages that release cytokines and nitric oxide, which results in inhibition of intestinal motility. Subsequent infiltration of circulating leukocytes into the intestinal wall contributes to cytokine and nitric oxide release and exacerbates ileus. Other factors contributing to ileus are endotoxemia; edema of the intestine wall subsequent to excessive fluid therapy; hypocalcemia; and long abdominal incisions. Because treatment of ileus with prokinetic drugs has not proven to be very effective, efforts should be directed at reducing its severity. Strategies which reduce the severity of ileus include pretreatment with a nonsteroidal anti-inflammatory drug, minimizing the length of the abdominal incision, reducing intestinal manipulation, intraoperative lidocaine infusion, correction of hypocalcemia, limiting the volume of intravenous fluids to prevent intestinal edema, and administration of alpha(2) antagonists.
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Affiliation(s)
- Thomas J Doherty
- Department of Large Animal Clinical Sciences, The University of Tennessee College of Veterinary Medicine, 2407 River Drive, Knoxville, TN 37996, USA.
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Seddighi MR, Egger CM, Rohrbach BW, Cox SK, Doherty TJ. Effects of tramadol on the minimum alveolar concentration of sevoflurane in dogs. Vet Anaesth Analg 2009; 36:334-40. [DOI: 10.1111/j.1467-2995.2009.00468.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wilson J, Doherty TJ, Egger CM, Fidler A, Cox S, Rohrbach B. Effects of intravenous lidocaine, ketamine, and the combination on the minimum alveolar concentration of sevoflurane in dogs. Vet Anaesth Analg 2008; 35:289-96. [DOI: 10.1111/j.1467-2995.2007.00389.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Pino LJ, Stashuk DW, Boe SG, Doherty TJ. Motor unit potential characterization using “pattern discovery”. Med Eng Phys 2008; 30:563-73. [PMID: 17697793 DOI: 10.1016/j.medengphy.2007.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 05/24/2007] [Accepted: 06/16/2007] [Indexed: 11/24/2022]
Abstract
Typically in clinical practice, electromyographers use qualitative auditory and visual analysis of electromyographic (EMG) signals to help infer if a neuromuscular disorder is present and if it is neuropathic or myopathic. Quantitative EMG methods exist that can more accurately measure feature values but require qualitative interpretation of a large number of statistics. Electrophysiological characterization of a neuromuscular system can be improved through the quantitative interpretation of EMG statistics. The aim of the present study was to compare the accuracy of pattern discovery (PD) characterization of motor unit potentials (MUPs) to other classifiers commonly used in the medical field. In addition, a demonstration of PD's transparency is provided. The transparency of PD characterization is a result of observing statistically significant events known as patterns. Using clinical MUP data from normal subjects and patients with known neuropathic disorders, PD achieved an error rate of 30.3% versus 29.8% for a Naïve Bayes classifier, 30.1% for a Decision Tree and 29% for discriminant analysis. Similar results were found for simulated EMG data. PD characterization succeeded in interpreting the information extracted from MUPs and transforming it into knowledge that is consistent with the literature and that can be valuable for the capture and transparent expression of clinically useful knowledge.
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Affiliation(s)
- L J Pino
- Systems Design Engineering, University of Waterloo, Canada.
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Doherty TJ, Kattesh HG, Adcock RJ, Welborn MG, Saxton AM, Morrow JL, Dailey JW. Effects of a concentrated lidocaine solution on the acute phase stress response to dehorning in dairy calves. J Dairy Sci 2007; 90:4232-9. [PMID: 17699042 DOI: 10.3168/jds.2007-0080] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The objective of this study was to more fully define the surgical stress response to dehorning by heat cauterization in dairy calves by measuring behavioral, hormonal, inflammatory, and immunological markers of stress and to determine whether a nerve block of the surgical site with a concentrated solution of lidocaine (5%) reduces the degree of stress. Thirty-two 10- to 12-wk-old female Holstein calves were randomly allotted to 1 of 4 treatments: 5% lidocaine followed by dehorning, 2% lidocaine followed by dehorning, saline followed by dehorning, or 5% lidocaine followed by sham dehorning. Plasma cortisol concentration was measured in blood samples collected via a jugular catheter at -0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 9, 12, 24, 48, and 72 h. Various other blood constituents were measured in samples collected at -0.5, 12, 24, 48, and 72 h. Feeding, drinking, scratching, grooming, rubbing, licking, and inactivity behaviors were observed in the standing and recumbent positions using a 10-min scan sampling method analyzed on a time period and daily basis for 72 h following the dehorning procedure. The frequency of vocalization, kicking, and lying in the chute during the dehorning procedure were also assessed. The overall plasma cortisol concentrations were higher in calves subjected to dehorning than in control calves. Compared with the control group, the saline-treated calves had a higher cortisol concentration at 30 and 60 min postdehorning. Plasma cortisol concentrations were higher in all groups at 30 min postdehorning than at other sampling times. The percentage of circulating neutrophils and the neutrophil:lymphocyte ratio were increased in the saline and 2% lidocaine group. Total plasma protein, fibrinogen, and alpha1-acid glycoprotein concentrations were similar among treatments. The behavioral response to dehorning, as manifested by kicking while in the chute, was greater in the saline and 2% lidocaine group than in the control or 5% lidocaine treatment groups. In the postdehorning period, the percentage of time calves spent performing various maintenance behaviors did not differ among treatments. Thus, injection of 5% lidocaine may not provide any added comfort after the dehorning but may decrease the overall stress response during the procedure.
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Affiliation(s)
- T J Doherty
- Department of Large Animal Clinical Sciences, The University of Tennessee, College of Veterinary Medicine, Knoxville 37996, USA
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Gurd BJ, Peters SJ, Heigenhauser GJF, LeBlanc PJ, Doherty TJ, Paterson DH, Kowalchuk JM. Prior heavy exercise elevates pyruvate dehydrogenase activity and speeds O2 uptake kinetics during subsequent moderate-intensity exercise in healthy young adults. J Physiol 2006; 577:985-96. [PMID: 16990406 PMCID: PMC1890376 DOI: 10.1113/jphysiol.2006.112706] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The adaptation of pulmonary oxygen uptake (.VO2) during the transition to moderate-intensity exercise (Mod) is faster following a prior bout of heavy-intensity exercise. In the present study we examined the activation of pyruvate dehydrogenase (PDHa) during Mod both with and without prior heavy-intensity exercise. Subjects (n = 9) performed a Mod(1)-heavy-intensity-Mod(2) exercise protocol preceded by 20 W baseline. Breath-by-breath .VO2 kinetics and near-infrared spectroscopy-derived muscle oxygenation were measured continuously, and muscle biopsy samples were taken at specific times during the transition to Mod. In Mod(1), PDHa increased from baseline (1.08 +/- 0.2 mmol min(-1) (kg wet wt)(-1)) to 30 s (2.05 +/- 0.2 mmol min(-1) (kg wet wt)(-1)), with no additional change at 6 min exercise (2.07 +/- 0.3 mmol min(-1) (kg wet wt)(-1)). In Mod(2), PDHa was already elevated at baseline (1.88 +/- 0.3 mmol min(-1) (kg wet wt)(-1)) and was greater than in Mod(1), and did not change at 30 s (1.96 +/- 0.2 mmol min(-1) (kg wet wt)(-1)) but increased at 6 min exercise (2.70 +/- 0.3 mmol min(-1) (kg wet wt)(-1)). The time constant of .VO2 was lower in Mod(2) (19 +/- 2 s) than Mod(1) (24 +/- 3 s). Phosphocreatine (PCr) breakdown from baseline to 30 s was greater (P < 0.05) in Mod(1) (13.6 +/- 6.7 mmol (kg dry wt)(-1)) than Mod(2) (6.5 +/- 6.2 mmol (kg dry wt)(-1)) but total PCr breakdown was similar between conditions (Mod(1), 14.8 +/- 7.4 mmol (kg dry wt)(-1); Mod(2), 20.1 +/- 8.0 mmol (kg dry wt)(-1)). Both oxyhaemoglobin and total haemoglobin were elevated prior to and throughout Mod(2) compared with Mod(1). In conclusion, the greater PDHa at baseline prior to Mod(2) compared with Mod(1) may have contributed in part to the faster .VO2 kinetics in Mod(2). That oxyhaemoglobin and total haemoglobin were elevated prior to Mod(2) suggests that greater muscle perfusion may also have contributed to the observed faster .VO2 kinetics. These findings are consistent with metabolic inertia, via delayed activation of PDH, in part limiting the adaptation of pulmonary .VO2 and muscle O2 consumption during the normal transition to exercise.
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Affiliation(s)
- B J Gurd
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, HSB 411C, The University of Western Ontario, London, Ontario, Canada N6A 5B9
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Murrell JC, White KL, Johnson CB, Taylor PM, Doherty TJ, Waterman-Pearson AE. Investigation of the EEG effects of intravenous lidocaine during halothane anaesthesia in ponies. Vet Anaesth Analg 2005; 32:212-21. [PMID: 16008718 DOI: 10.1111/j.1467-2995.2005.00201.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To record the electroencephalographic changes during castration in ponies anaesthetized with halothane and given intravenous (IV) lidocaine by infusion. The hypothesis tested was that in ponies, IV lidocaine is antinociceptive and would therefore obtund EEG changes during castration. ANIMALS Ten Welsh mountain ponies referred to the Department of Clinical Veterinary Medicine, Cambridge for castration under general anaesthesia. MATERIALS AND METHODS Following pre-anaesthetic medication with intramuscular acepromazine (0.02 mg kg(-1)) anaesthesia was induced with IV guaiphenesin (60 mg kg(-1)) and thiopental (9 mg kg(-1)) and maintained with halothane at an end-tidal concentration (FE'HAL) of 1.2%. A constant rate infusion of IV lidocaine (100 microg kg(-1) minute(-1)) was administered throughout anaesthesia. The electroencephalogram (EEG) was recorded continuously using subcutaneous needle electrodes. All animals were castrated using a closed technique. The raw EEG signal was analysed after completion of each investigation, and the mean values of EEG variables (median frequency, spectral edge frequency, total amplitude) recorded during a baseline period (before surgery began) and the removal of each testicle were compared using anova for repeated measures. RESULTS Spectral edge frequency (SEF) 95% decreased during removal of the second testicle compared with baseline recordings. No other significant EEG changes during castration were measured. CONCLUSIONS Lidocaine obtunded the EEG changes identified during castration in a previous control study, providing indirect evidence that lidocaine administered peri-operatively was antinociceptive and contributed to anaesthesia during castration. CLINICAL RELEVANCE The antinociceptive effect of lidocaine combined with its minimal cardiovascular effects indicate a potential use for systemic lidocaine in clinical anaesthetic techniques.
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Affiliation(s)
- Joanna C Murrell
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, University Utrecht, Utrecht, The Netherlands.
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Abstract
OBJECTIVE To determine the influence of a low-dose constant rate infusion (LCRI; 50 microg kg(-1) minute(-1)) and high-dose CRI (HCRI; 200 microg kg(-1) minute(-1)) lidocaine infusion on the minimum alveolar concentration (MAC) of isoflurane (I) in dogs. STUDY DESIGN Prospective experimental study. ANIMALS Ten mongrel dogs (four females, six males), weighing 20-26.3 kg. METHODS Dogs were anesthetized with I in oxygen and their lungs mechanically ventilated. Baseline MAC was determined using mechanical or electrical stimuli. Lidocaine (2 mg kg(-1) IV) was administered over 3 minutes, followed by the LCRI and MAC determination commenced 30 minutes later. Once MAC was determined following LCRI, the lidocaine infusion was stopped for 30 minutes. A second bolus of lidocaine (2 mg kg(-1), IV) was administered, followed by the HCRI and MAC re-determined. Concentrations of lidocaine and its metabolites were measured at end-tidal I concentrations immediately above and below MAC. Heart rates and blood pressures were measured. RESULTS Minimum alveolar concentration of I was 1.34 +/- 0.11 (%; mean +/- SD) for both types of stimulus. The LCRI significantly reduced MAC to 1.09 +/- 0.13 (18.7% reduction) and HCRI to 0.76 +/- 0.10 (43.3% reduction). Plasma concentrations (ng mL(-1), median; value below and above MAC, respectively) for LCRI were: lidocaine, 1465 and 1537; glycinexylidide (GX), 111 and 181; monoethylglycinexylidide (MEGX), 180 and 471 and for HCRI were: lidocaine, 4350 and 4691; GX, 784 and 862; MEGX, 714 and 710. Blood pressure was significantly increased at 30 minutes after high dose infusion. CONCLUSION AND CLINICAL RELEVANCE Lidocaine infusions reduced the MAC of I in a dose-dependent manner and did not induce clinically significant changes on heart rate or blood pressure.
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Affiliation(s)
- Alexander Valverde
- Department of Large Animal Clinical Sciences, University of Florida, Gainesville, FL 32610, USA.
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Tarnopolsky MA, Mahoney DJ, Vajsar J, Rodriguez C, Doherty TJ, Roy BD, Biggar D. Creatine monohydrate enhances strength and body composition in Duchenne muscular dystrophy. Neurology 2004; 62:1771-7. [PMID: 15159476 DOI: 10.1212/01.wnl.0000125178.18862.9d] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether creatine monohydrate (CrM) supplementation increases strength and fat-free mass (FFM) in boys with Duchenne muscular dystrophy (DD). METHODS Thirty boys with DD (50% were taking corticosteroids) completed a double-blind, randomized, cross-over trial with 4 months of CrM (about 0.10 g/kg/day), 6-week wash-out, and 4 months of placebo. Measurements were completed of pulmonary function, compound manual muscle and handgrip strength, functional tasks, activity of daily living, body composition, serum creatine kinase and gamma-glutamyl transferase activity and creatinine, urinary markers of myofibrillar protein breakdown (3-methylhistidine), DNA oxidative stress (8-hydroxy-2-deoxyguanosine [8-OH-2-dG]), and bone degradation (N-telopeptides). RESULTS During the CrM treatment phase, there was an increase in handgrip strength in the dominant hand and FFM (p < 0.05), with a trend toward a loss of global muscle strength (p = 0.056) only for the placebo phase, with no improvements in functional tasks or activities of daily living. Corticosteroid use, but not CrM treatment, was associated with a lower 8-OH-2-dG/creatinine (p < 0.05), and CrM treatment was associated with a reduction in N-telopeptides (p < 0.05). CONCLUSIONS Four months of CrM supplementation led to increases in FFM and handgrip strength in the dominant hand and a reduction in a marker of bone breakdown and was well tolerated in children with DD.
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Affiliation(s)
- M A Tarnopolsky
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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Doherty TJ, Andrews FM, Blackford JT, Rohrbach BW, Sandin A, Saxton AM. Effects of lipopolysaccharide and phenylbutazone on gastric contents in the horse. Equine Vet J 2003; 35:472-5. [PMID: 12875325 DOI: 10.2746/042516403775600488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Endotoxaemia causes a disruption of gastrointestinal motility in the horse but there is no information on its effects on gastric secretion. Lipopolysaccharide (LPS) administration is known to affect gastric secretion in other species. HYPOTHESIS That LPS, a toxic component of Gram-negative bacteria, would reduce gastric acid secretion and that pretreatment with phenylbutazone (PBZ) would block the effects of LPS. METHODS The effects of LPS and PBZ on gastric contents were investigated in fasted, mature horses, with permanent gastric cannulae. Horses were pretreated with either saline or PBZ 15 mins before a 60 min infusion of either LPS or saline. Gastric contents were collected at 15 min intervals for 3 h, beginning 15 mins after the start of the LPS or saline infusion. RESULTS Lipopolysaccharide significantly decreased gastric acid output, [K+] and potassium output and increased [Na+] and sodium output. Phenylbutazone did not affect basal gastric acid secretion but decreased LPS-induced changes in the secreted volume, [Na+] and sodium output. CONCLUSIONS This study provides evidence that LPS affects gastric acid secretion in the horse and that these LPS-induced changes are mediated, in part, by prostaglandins. POTENTIAL RELEVANCE Lipopolysaccharide administration can induce changes in the composition of gastric contents in the horse but further work is needed to determine the source of these changes.
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Affiliation(s)
- T J Doherty
- College of Veterinary Medicine, PO Box 1071, The University of Tennessee, Knoxville, Tennessee 37901, USA
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Affiliation(s)
- T J Doherty
- Department Of Large Animal Clinical Sciences, The University Of Tennessee, College Of Veterinary Medicine, Knoxville 37901-1071, USA.
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Affiliation(s)
- T J Doherty
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.
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Affiliation(s)
- T Eastman
- Department of Large Animal Medicine & Surgery, College of Veterinary Medicine, Texas A&M University, College Station 77843-4475, USA
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Abstract
This brief review examines the influence of aging on skeletal muscle mass and strength and specifically highlights sex-related differences. It is well established that aging is associated with a significant decline in muscle strength that becomes functionally important by the seventh decade of life. Age-related strength losses are mainly secondary to decline in skeletal muscle mass in men and women. While women may experience earlier strength losses than men, overall, age associated decreases in strength are similar when controlling for muscle mass. Although men may experience greater losses of total muscle mass, recent evidence, however, points toward greater declines in muscle quality in older women. The implications and potential mechanisms for these differences are discussed.
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Affiliation(s)
- T J Doherty
- Department of Physical Medicine and Rehabilitation, Faculty of Medicine and Dentistry, University of Western Ontario, London, Canada.
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Abstract
The primary function of skeletal muscle is to produce force for postural control and movement. Although the contractile properties of the whole muscle are useful functional indicators, they do not accurately reflect the heterogeneity of the constituent motor units (MUs) and their changes in health and disease. However, data on the contractile properties of human MUs, in comparison to other animal species, are relatively sparse. This, in part, is due to greater methodological challenges of in vivo studies of MUs in the human. The purpose of this review is to critically appraise the methods used in humans; to describe the normative data from different muscle groups; to discuss differences between data from healthy humans and other animal species; and, last, to characterize changes of the MU contractile properties in aging, disease, and in response to intervention. Because the spike-triggered averaging technique can only be used to study the twitch properties, other methods were subsequently developed to measure a wider range of contractile properties. Although there is general agreement between human data and those from other animal species, major differences do exist. Potential reasons for these discrepancies include true biological differences, but differences in the techniques used may also be responsible. Although limited, measurement of MU contractile properties in humans has provided insight into the changes associated with aging and motoneuronal diseases and provides a means of gauging their adaptive capacity for training and immobilization.
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Affiliation(s)
- K M Chan
- Division of Physical Medicine and Rehabilitation, University of Alberta, 513 Heritage Medical Research Center, Edmonton, Alberta T6J 2S2, Canada.
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