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Marchese GA, Crystal J, Louro LF. Incidence of severe hypoxaemia in anaesthetised horses undergoing emergency exploratory laparotomy. J Equine Vet Sci 2022; 116:104026. [PMID: 35659514 DOI: 10.1016/j.jevs.2022.104026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/29/2022] [Accepted: 05/26/2022] [Indexed: 11/19/2022]
Abstract
Prevalence and risk factors of severe hypoxaemia in anaesthetised horses undergoing emergency exploratory laparotomy are sparsely documented. The aim of this study was to report incidence of severe hypoxaemia ( PaO 2 < 60 mmHg) in horses undergoing emergency exploratory laparotomy and identify potential risk factors for this complication. A single centre retrospective cross sectional designed was used. Clinical data of 714 horses undergoing general anaesthesia for emergency explorative laparotomy were reviewed. A backward stepwise elimination procedure was used to determine the final multivariable logistic regression model; all covariables with univariable P-values <0.25 were incorporated, with retention of covariables with Wald P-values <0.05 at each step, in order to determine which explanatory variables would be included in the final model. The overall incidence of severe hypoxaemia in our population was 15.3%. Multivariable logistic regression analysis showed that increasing body weight (OR 1.01, 95% CI 1.0-1.01, P = .002), colon torsion (OR 3.0, 95% CI 1.3-6.8, P = .006), increased dead space ventilation (OR 1.06, 95% CI 1.04-1.09, P = <0.001), shorter time between induction of anaesthesia and collection of arterial blood gas samples (OR 0.98, 95% CI 0.98-0.99, P = <0.001) and intra-tracheal aerosolised salbutamol (OR 13.5, 95% CI 7.6-24, P = <0.001) were associated with the outcome. The incidence of hypoxaemia found in our study was in line with previous literature. Increasing body weight, colon torsion and shorter time between the time of induction of anaesthesia and collection of arterial blood gas samples represented risk factors for hypoxaemia.
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Affiliation(s)
- Giorgia Anna Marchese
- School of Veterinary Science, Leahurst Campus, University of Liverpool, Neston, Wirral, UK; Willows Veterinary Centre and Referral Service, Solihull, UK.
| | - Joanna Crystal
- School of Veterinary Science, Leahurst Campus, University of Liverpool, Neston, Wirral, UK
| | - Luís Filipe Louro
- School of Veterinary Science, Leahurst Campus, University of Liverpool, Neston, Wirral, UK; ChesterGates Veterinary Specialists, Wirral, UK
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Tucker L, Almeida D, Wendt-Hornickle E, Baldo CF, Allweiler S, Guedes AGP. Effect of 15° Reverse Trendelenburg Position on Arterial Oxygen Tension during Isoflurane Anesthesia in Horses. Animals (Basel) 2022; 12:ani12030353. [PMID: 35158676 PMCID: PMC8833611 DOI: 10.3390/ani12030353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/21/2022] [Accepted: 01/25/2022] [Indexed: 12/04/2022] Open
Abstract
Simple Summary Horses commonly develop low blood oxygen levels during anesthesia, especially when they are placed on their backs. This study investigated whether a 15° head-up tilt, in a homogenous group of anesthetized horses positioned on their backs, would result in better blood oxygen levels as compared to no tilt. The results showed significantly greater blood oxygen levels with tilt compared to no tilt in five out of six horses tested. In one horse the effect was the opposite. The concurrent effect on cardiovascular function remains to be tested in detail. Further studies are needed to confirm these findings in a larger group of horses and to determine the effects on blood pressure and treatment options. Abstract Lower than expected arterial oxygen tension (PaO2) continues to be an unresolved problem in equine anesthesia. The aim of this randomized, crossover, and prospective study using six adult horses is to determine if a 15° reverse Trendelenburg position (RTP) increases PaO2 during inhalation anesthesia. Under constant-dose isoflurane anesthesia, dorsally recumbent horses were positioned either horizontally (HP) or in a 15° RTP for 2 h. Lungs were mechanically ventilated (15 mL/kg, 6 breaths/min). Arterial carbon dioxide tension (PaCO2), PaO2, inspired oxygen fraction (FiO2), and end-tidal carbon dioxide tension (EtCO2) were determined every 30 min during anesthesia. Indices of dead-space ventilation (Vd/Vt), oxygenation (P–F ratio), and perfusion (F–shunt) were calculated. Dobutamine and phenylephrine were used to support mean arterial pressure (MAP). Data are presented as median and range. In one horse, which was deemed an outlier due to its thoracic dimensions and body conformation, indices of oxygenation worsened in RTP compared to HP (median PaO2 438 vs. 568 mmHg; P–F ratio 454 vs. 586 mmHg, and F–shunt 13.0 vs. 5.7 mmHg). This horse was excluded from calculations. In the remaining five horses they were significantly better with RTP compared to HP. Results in remaining five horses showed that PaO2 (502, 467–575 vs. 437, 395–445 mmHg), P-F ratio (518, 484–598 vs. 455, 407–458 mmHg), and F-shunt (10.1, 4.2–11.7 vs. 14.2, 13.8–16.0 mmHg) were significantly different between RTP and HP (p = 0.03). Other variables were not significantly different. In conclusion, the 15° RTP resulted in better oxygenation than HP in dorsally recumbent, isoflurane-anesthetized horses, although worsening of oxygenation may occur in individual horses. A study detailing the cardiovascular consequences of RTP is necessary before it can be recommended for clinical practice.
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Affiliation(s)
- Laura Tucker
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; (L.T.); (D.A.); (E.W.-H.); (C.F.B.); (S.A.)
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Daniel Almeida
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; (L.T.); (D.A.); (E.W.-H.); (C.F.B.); (S.A.)
| | - Erin Wendt-Hornickle
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; (L.T.); (D.A.); (E.W.-H.); (C.F.B.); (S.A.)
| | - Caroline F. Baldo
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; (L.T.); (D.A.); (E.W.-H.); (C.F.B.); (S.A.)
- Boston Scientific, Research and Technology Center, Arden Hills, MN 55112, USA
| | - Sandra Allweiler
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; (L.T.); (D.A.); (E.W.-H.); (C.F.B.); (S.A.)
| | - Alonso G. P. Guedes
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; (L.T.); (D.A.); (E.W.-H.); (C.F.B.); (S.A.)
- Correspondence:
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Stefanik E, Drewnowska O, Lisowska B, Turek B. Causes, Effects and Methods of Monitoring Gas Exchange Disturbances during Equine General Anaesthesia. Animals (Basel) 2021; 11:2049. [PMID: 34359177 PMCID: PMC8300395 DOI: 10.3390/ani11072049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/30/2021] [Accepted: 07/06/2021] [Indexed: 02/06/2023] Open
Abstract
Horses, due to their unique anatomy and physiology, are particularly prone to intraoperative cardiopulmonary disorders. In dorsally recumbent horses, chest wall movement is restricted and the lungs are compressed by the abdominal organs, leading to the collapse of the alveoli. This results in hypoventilation, leading to hypercapnia and respiratory acidosis as well as impaired tissue oxygen supply (hypoxia). The most common mechanisms disturbing gas exchange are hypoventilation, atelectasis, ventilation-perfusion (V/Q) mismatch and shunt. Gas exchange disturbances are considered to be an important factor contributing to the high anaesthetic mortality rate and numerous post-anaesthetic side effects. Current monitoring methods, such as a pulse oximetry, capnography, arterial blood gas measurements and spirometry, may not be sufficient by themselves, and only in combination with each other can they provide extensive information about the condition of the patient. A new, promising, complementary method is near-infrared spectroscopy (NIRS). The purpose of this article is to review the negative effect of general anaesthesia on the gas exchange in horses and describe the post-operative complications resulting from it. Understanding the changes that occur during general anaesthesia and the factors that affect them, as well as improving gas monitoring techniques, can improve the post-aesthetic survival rate and minimize post-operative complications.
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Affiliation(s)
- Elżbieta Stefanik
- Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
| | - Olga Drewnowska
- Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
| | - Barbara Lisowska
- National Geriatrics, Rheumatology and Rehabilitation Institute, Spartańska 1, 02-637 Warsaw, Poland;
| | - Bernard Turek
- Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
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Moreno‐Martinez F, Mosing M, Senior M. Controlled mechanical ventilation in equine anaesthesia: Physiological background and basic considerations (Part 1). EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- F. Moreno‐Martinez
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
| | - M. Mosing
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
| | - M. Senior
- Department of Equine Clinical Science Institute of Veterinary Science University of Liverpool Neston, Cheshire UK
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Varner KM, Hopster K, Driessen B. Comparison of various types of inert gas components on efficacy of an alveolar recruitment maneuver in dorsally recumbent anesthetized horses. Am J Vet Res 2019; 80:631-636. [PMID: 31246120 DOI: 10.2460/ajvr.80.7.631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To assess effects of nitrogen and helium on efficacy of an alveolar recruitment maneuver (ARM) for improving pulmonary mechanics and oxygen exchange in anesthetized horses. ANIMALS 6 healthy adult horses. PROCEDURES Horses were anesthetized twice in a randomized crossover study. Isoflurane-anesthetized horses in dorsal recumbency were ventilated with 30% oxygen and 70% nitrogen (treatment N) or heliox (30% oxygen and 70% helium; treatment H) as carrier gas. After 60 minutes, an ARM was performed. Optimal positive end-expiratory pressure was identified and maintained for 120 minutes. Throughout the experiment, arterial blood pressures, heart rate, peak inspiratory pressure, dynamic compliance (Cdyn), and Pao2 were measured. Variables were compared with baseline values and between treatments by use of an ANOVA. RESULTS The ARM resulted in significant increases in Pao2 and Cdyn and decreases in the alveolar-arterial gradient in the partial pressure of oxygen in all horses. After the ARM and during the subsequent 120-minute phase, mean values were significantly lower for treatment N than treatment H for Pao2 and Cdyn. Optimal positive end-expiratory pressure was consistently 15 cm H2O for treatment N, but it was 10 cm H2O (4 horses) and 15 cm H2O (2 horses) for treatment H. CONCLUSIONS AND CLINICAL RELEVANCE An ARM in anesthetized horses might be more efficacious in improving Pao2 and Cdyn when animals breathe helium instead of nitrogen as the inert gas.
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Dupont J, Serteyn D, Sandersen C. Prolonged Recovery From General Anesthesia Possibly Related to Persistent Hypoxemia in a Draft Horse. Front Vet Sci 2018; 5:235. [PMID: 30327770 PMCID: PMC6174201 DOI: 10.3389/fvets.2018.00235] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/10/2018] [Indexed: 01/26/2023] Open
Abstract
Horses are susceptible to developing large areas of pulmonary atelectasis during recumbency and anesthesia. The subsequent pulmonary shunt is responsible for significant impairment of oxygenation. Since ventilation perfusion mismatch persists into the post-operative period, hypoxemia remains an important concern in the recovery stall. This case report describes the diagnosis and supportive therapy of persistent hypoxemia in a 914 kg draft horse after isoflurane anesthesia. It highlights how challenging it can be to deal with hypoxemia after disconnection from the anesthesia machine and how life-threatening it can become if refractory to treatment. Furthermore, it stresses the point on the interactions between hypoxemia and other factors, such as residual drug effects and hypothermia, that should also be considered in the case of delayed recovery from general anesthesia.
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Affiliation(s)
- Julien Dupont
- Department of Clinical Sciences, Anesthesiology and Equine Surgery, Faculty of Veterinary Medicine, University of Liege, Liège, Belgium
| | - Didier Serteyn
- Department of Clinical Sciences, Anesthesiology and Equine Surgery, Faculty of Veterinary Medicine, University of Liege, Liège, Belgium
| | - Charlotte Sandersen
- Department of Clinical Sciences, Anesthesiology and Equine Surgery, Faculty of Veterinary Medicine, University of Liege, Liège, Belgium
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Mosing M, Senior JM. Maintenance of equine anaesthesia over the last 50 years: Controlled inhalation of volatile anaesthetics and pulmonary ventilation. Equine Vet J 2018; 50:282-291. [DOI: 10.1111/evj.12793] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/24/2017] [Indexed: 01/06/2023]
Affiliation(s)
- M. Mosing
- Murdoch University School of Veterinary and Life Sciences; Murdoch Western Australia Australia
| | - J. M. Senior
- Department of Equine Clinical Science; Institute of Veterinary Science; University of Liverpool; Neston Cheshire UK
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Wright BD, Hildebrand SV. An evaluation of apnea or spontaneous ventilation in early recovery following mechanical ventilation in the anesthetized horse. Vet Anaesth Analg 2016; 28:26-33. [PMID: 28403999 DOI: 10.1046/j.1467-2995.2001.00015.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/1999] [Accepted: 12/27/1999] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare arterial oxygen and carbon dioxide tensions in apneic and spontaneously ventilating horses recovering from anesthesia. STUDY DESIGN Randomized clinical trial. ANIMAL POPULATION Forty-two healthy horses averaging 466 ± 106 kg and 6 ± 5 years of age. METHODS Anesthetized horses undergoing a variety of surgical procedures and receiving positive pressure ventilation (IPPV) were divided into two equal groups. One group was allowed to return to spontaneous ventilation prior to disconnection from the anesthetic circuit (weaned). The other group remained apneic during transport to a recovery stall. Arterial blood gas data were collected at five time points: 20 minutes before moving to a recovery stall (t = - 20); at the time the anesthetic circuit was disconncted (t = 0); at 3 and 5 minutes post-disconnection (t = 3 and t = 5) and at the time of the first spontaneous breath (t = sv). The data were analyzed using an anova method for repeated measures and paired, two-tailed t-tests. Significance was assumed when p < 0.05. RESULTS The apneic group took a mean of 5 minutes 18 seconds (± 135 seconds) before starting spontaneous ventilation. This group maintained significantly higher PaO2 levels at intermediate time points (t = 0 and t = 3) but no difference was noted after 5 minutes. PaCO2 levels were higher in the weaned group at time 0 minutes, returning to a comparable level to the apneic group at t = 3 minutes. CONCLUSIONS AND CLINICAL RELEVANCE Horses can survive a short period of apnea during transport from the surgery suite to recovery stall and may benefit from a reduced incidence of transient hypoxemia compared with spontaneously ventilating horses. This information has practical implications for the anesthetist evaluating the options for discontinuing IPPV when horses are moved to a recovery stall.
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Affiliation(s)
- Bonnie D Wright
- University of California School of Veterinary Medicine, Department of Surgical and Radiological Sciences, Davis, CA, USA
| | - Susan V Hildebrand
- University of California School of Veterinary Medicine, Department of Surgical and Radiological Sciences, Davis, CA, USA
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9
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Guedes A, Aleman M, Davis E, Tearney C. Cardiovascular, respiratory and metabolic responses to apnea induced by atlanto-occipital intrathecal lidocaine injection in anesthetized horses. Vet Anaesth Analg 2016; 43:590-598. [PMID: 26849108 DOI: 10.1111/vaa.12344] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/28/2015] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine physiologic responses to apnea-induced severe hypoxemia in anesthetized horses. STUDY DESIGN Prospective experimental study. ANIMALS Six university-owned horses with a median (range) body weight of 500 (220-510) kg and aged 13.5 (0.8-24.0) years scheduled for euthanasia. METHODS Xylazine-midazolam-ketamine-anesthetized horses breathing room air spontaneously were instrumented with a facial artery catheter for pressure measurement and blood sampling, and were made apneic with atlanto-occipital intrathecal lidocaine (4 mg kg-1 ). Cardiopulmonary, biochemical and hematologic variables were recorded before (baseline) and every minute for 10 minutes after lidocaine injection. RESULTS PaO2 values were: baseline, 55 mmHg (7.3 kPa); 1 minute, 28 mmHg (3.8 kPa); 2 minutes, 18 mmHg (2.4 kPa); 3 minutes, 15 mmHg (2.0 kPa), and 4-10 minutes, (8-11 mmHg (1.1-1.5 kPa). PaCO2 values were: baseline, 50 mmHg (6.7 kPa); 1 minute, 61 mmHg (8.1 kPa), and 2-10 minutes, 64-66 mmHg (8.5-8.8 kPa). Base excess values at baseline, 1 minute and 2-10 minutes were 5.3 mmol L-1 , 6.5 mmol L-1 and 7.0-8.1 mmol L-1 , respectively. Pulse rates at baseline, 1 minute and 2-7 minutes were 36, 53 and 54-85 beats minute-1 , respectively. Asystole occurred at 8 minutes. Pulse pressures were 50 mmHg at baseline and 1 minute, and 39 mmHg, 31 mmHg, 22 mmHg, 17 mmHg and 1-9 mmHg at 2, 3, 4, 5 and 6-10 minutes, respectively. Lactate was 0.9 mmol L-1 at baseline, progressively increasing to 1.7-2.4 mmol L-1 at 7-10 minutes. Packed cell volume increased after 7 minutes of apnea. There were no other major changes. CONCLUSIONS AND CLINICAL RELEVANCE Apnea immediately exacerbated hypoxemia and hypercapnia and rapidly caused hemodynamic instability. Apnea in hypoxemic anesthetized horses is associated with a serious risk for progress to cardiovascular collapse.
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Affiliation(s)
- Alonso Guedes
- Department of Surgical and Radiological Sciences, University of California, Davis, CA, USA. .,Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA.
| | - Monica Aleman
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Eric Davis
- International Animal Welfare Training Institute, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Caitlin Tearney
- William R Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA, USA
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Ishizuka T, Tamura J, Nagaro T, Sudo K, Itami T, Umar MA, Miyoshi K, Sano T, Yamashita K. Effects of intermittent positive pressure ventilation on cardiopulmonary function in horses anesthetized with total intravenous anesthesia using combination of medetomidine, lidocaine, butorphanol and propofol (MLBP-TIVA). J Vet Med Sci 2014; 76:1577-82. [PMID: 25649938 PMCID: PMC4300371 DOI: 10.1292/jvms.14-0077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Effects of intermittent
positive pressure ventilation (IPPV) on cardiopulmonary function were evaluated in horses
anesthetized with total intravenous anesthesia using constant rate infusions of
medetomidine (3.5 µg/kg/hr), lidocaine (3 mg/kg/hr), butorphanol (24
µg/kg/hr) and propofol (0.1 mg/kg/min) (MLBP-TIVA). Five horses were
anesthetized twice using MLBP-TIVA with or without IPPV at 4-week interval (crossover
study). In each occasion, the horses breathed 100% oxygen with spontaneous ventilation
(SB-group, n=5) or with IPPV (CV-group, n=5), and changes in cardiopulmonary parameters
were observed for 120 min. In the SB-group, cardiovascular parameters were maintained
within acceptable ranges (heart rate: 33–35 beats/min, cardiac output: 27–30
l/min, mean arterial blood pressure [MABP]: 114–123 mmHg, mean
pulmonary arterial pressure [MPAP]: 28–29 mmHg and mean right atrial pressure [MRAP]:
19–21 mmHg), but severe hypercapnea and insufficient oxygenation were observed (arterial
CO2 pressure [PaCO2]: 84–103 mmHg and arterial O2
pressure [PaO2]: 155–172 mmHg). In the CV-group, normocapnea (PaCO2:
42–50 mmHg) and good oxygenation (PaO2: 395–419 mmHg) were achieved by the IPPV
without apparent cardiovascular depression (heart rate: 29–31 beats/min, cardiac output:
17–21 l /min, MABP: 111–123 mmHg, MPAP: 27–30 mmHg and MRAP: 15–16 mmHg).
MLBP-TIVA preserved cardiovascular function even in horses artificially ventilated.
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Affiliation(s)
- Tomohito Ishizuka
- Departments of Small Animal Clinical Sciences School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
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Intravenous butorphanol improves cardiopulmonary parameters in game-ranched white rhinoceroses (Ceratotherium simum) immobilized with etorphine and azaperone. J Wildl Dis 2014; 50:849-57. [PMID: 25105814 DOI: 10.7589/2013-12-327] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract We immobilized 47 white rhinoceroses (Ceratotherium simum) for dehorning with 1-4 mg of etorphine HCl, 10-40 mg of azaperone, and 7,500 IU of hyaluronidase, at a game ranch in South Africa in November 2012. Forty-four received butorphanol intravenously 5 min after recumbency, at the rate of 10 mg of butorphanol per 1 mg of etorphine, and three animals did not. When possible, blood gas and physiologic parameters were measured immediately before butorphanol administration and 10 min later. Statistically significant improvements were observed, with a reduction in pH, partial pressure of carbon dioxide in arterial blood, heart rate, systolic blood pressure, and diastolic blood pressure, and with an increase in arterial partial pressure of oxygen, arterial hemoglobin oxygen saturation, and respiratory rate in animals administered butorphanol. In the three animals that did not receive butorphanol, no improvement was apparent. Butorphanol given to recumbent white rhinoceroses immediately after immobilization was associated with improved blood gas values and cardiopulmonary function for at least 10 min. Studies on the sustainability of these effects are necessary.
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Hubbell JAE, Muir WW. Oxygenation, oxygen delivery and anaesthesia in the horse. Equine Vet J 2014; 47:25-35. [DOI: 10.1111/evj.12258] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 02/26/2014] [Indexed: 11/30/2022]
Affiliation(s)
- J. A. E. Hubbell
- The Department of Veterinary Clinical Sciences; College of Veterinary Medicine; The Ohio State University; Columbus USA
| | - W. W. Muir
- Veterinary Clinical Pharmacology Consulting Services; Columbus Ohio USA
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Ida KK, Fantoni DT, Ibiapina BT, Souto MTMR, Zoppa ALV, Silva LCLC, Ambrósio AM. Effect of postoperative xylazine administration on cardiopulmonary function and recovery quality after isoflurane anesthesia in horses. Vet Surg 2013; 42:877-84. [PMID: 24033770 DOI: 10.1111/j.1532-950x.2013.12050.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 12/01/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To evaluate equine cardiopulmonary function and recovery quality after administration of 0.25 or 0.50 mg/kg xylazine intravenously (IV) during recovery. STUDY DESIGN Randomized, blinded, prospective, clinical study. ANIMALS Horses (n = 20). METHODS During recovery after 3 hours of isoflurane anesthesia for arthroscopic surgery, horses were administered either 0.25 mg/kg (G25, n = 10) or 0.50 mg/kg (G50, n = 10) xylazine intravenously. Vital signs and arterial blood samples were obtained during recovery before sedation (baseline), 5, 10, 20, 30, and 45 minutes after xylazine and 30 minutes after standing. The quality of recovery scores ranged from 10 to 72 (10 = best, 72 = worst). RESULTS G25 horses recovered faster (mean ± SD, 33 ± 5 min) than G50 horses (50 ± 7 min, P < .0001). Mean maximal decrease in arterial oxygen tension was 55 ± 11 mmHg in G25 (at 10 minutes; P < .05) and 54 ± 7 mmHg in G50 (at 20 minutes; P < .01). G25 group had a total recovery score (23 [range 18-29]) and number of attempts to stand (4 ± 2) greater than the G50 group (18 [10-23] and 1 ± 1, respectively; P < .001). CONCLUSIONS Both doses of xylazine promoted a moderate and transient hypoxemia during recovery; however, the 0.5 mg/kg dose produced a longer and improved quality of recovery from anesthesia.
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Affiliation(s)
- Keila K Ida
- Laboratório de Investigação Médica LIM-08, Anestesiologia, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, Brazil
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14
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Moens Y. Mechanical Ventilation and Respiratory Mechanics During Equine Anesthesia. Vet Clin North Am Equine Pract 2013; 29:51-67. [DOI: 10.1016/j.cveq.2012.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Crumley MN, Hodgson DS, Kreider SE. Effects of tidal volume, ventilatory frequency, and oxygen insufflation flow on the fraction of inspired oxygen in cadaveric horse heads attached to a lung model. Am J Vet Res 2011; 73:134-9. [PMID: 22204299 DOI: 10.2460/ajvr.73.1.134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To measure the effects of tidal volume, ventilatory frequency, and oxygen insufflation flow on the fraction of inspired oxygen in cadaveric horse heads attached to a lung model. SAMPLE 8 heads of equine cadavers. PROCEDURES Each cadaveric horse head was intubated with a nasotracheal tube that extended into the proximal portion of the trachea. Oxygen was delivered through an oxygen catheter contained within and extending to the tip of the nasotracheal tube. The trachea was connected to the lung model by use of a spiral-wound hose with a sampling adaptor. Eight treatment combinations involving 2 tidal volumes (5 and 8 L), 2 ventilatory frequencies (6 and 12 mechanical breathes/min), and 2 insufflation rates (10 and 15 L/min) were applied to each head. Hand-drawn inspired gas samples were collected and analyzed for oxygen concentrations. RESULTS The fraction of inspired oxygen (measured at mid trachea) ranged from 26.8% to 39.4%. Fraction of inspired oxygen was significantly higher with a smaller tidal volume, lower ventilatory frequency, and higher insufflation rate. CONCLUSIONS AND CLINICAL RELEVANCE In the study model, measured fraction of inspired oxygen varied with ventilatory pattern as well as oxygen insufflation rate. Clinically, this information could be beneficial for interpretation of data regarding arterial blood gases and hemoglobin saturation and in making appropriate oxygen insufflation decisions for anesthetized horses that are breathing room air.
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Affiliation(s)
- Mariana N Crumley
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
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Hubbell JAE, Aarnes TK, Bednarski RM, Lerche P, Muir WW. Effect of 50% and maximal inspired oxygen concentrations on respiratory variables in isoflurane-anesthetized horses. BMC Vet Res 2011; 7:23. [PMID: 21639886 PMCID: PMC3133541 DOI: 10.1186/1746-6148-7-23] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 06/03/2011] [Indexed: 11/13/2022] Open
Abstract
Background The purpose of this study was to compare the effects of 0.5 fraction of inspired oxygen (FiO2) and >0.95 FiO2 on pulmonary gas exchange, shunt fraction and oxygen delivery (DO2) in dorsally recumbent horses during inhalant anesthesia. The use of 0.5 FiO2 has the potential to reduce absorption atelectasis (compared to maximal FiO2) and augment alveolar oxygen (O2) tensions (compared to ambient air) thereby improving gas exchange and DO2. Our hypothesis was that 0.5 FiO2 would reduce ventilation-perfusion mismatching and increase the fraction of pulmonary blood flow that is oxygenated, thus improving arterial oxygen content and DO2. Results Arterial partial pressures of O2 were significantly higher than preanesthetic levels at all times during anesthesia in the >0.95 FiO2 group. Arterial partial pressures of O2 did not change from preanesthetic levels in the 0.5 FiO2 group but were significantly lower than in the >0.95 FiO2 group from 15 to 90 min of anesthesia. Alveolar to arterial O2 tension difference was increased significantly in both groups during anesthesia compared to preanesthetic values. The alveolar to arterial O2 tension difference was significantly higher at all times in the >0.95 FiO2 group compared to the 0.5 FiO2 group. Oxygen delivery did not change from preanesthetic values in either group during anesthesia but was significantly lower than preanesthetic values 10 min after anesthesia in the 0.5 FiO2 group. Shunt fraction increased in both groups during anesthesia attaining statistical significance at varying times. Shunt fraction was significantly increased in both groups 10 min after anesthesia but was not different between groups. Alveolar dead space ventilation increased after 3 hr of anesthesia in both groups. Conclusions Reducing FiO2 did not change alveolar dead space ventilation or shunt fraction in dorsally recumbent, mechanically ventilated horses during 3 hr of isoflurane anesthesia. Reducing FiO2 in dorsally recumbent isoflurane anesthetized horses does not improve oxygenation or oxygen delivery.
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Affiliation(s)
- John A E Hubbell
- Deparment of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
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SILVER IA, JEFFCOTT LB, ROSSDALE PD. Fifty years of the British Equine Veterinary Association as a facilitator of progress in equine clinical science. Equine Vet J 2011; 43:618-31. [DOI: 10.1111/j.2042-3306.2011.00379.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hopster K, Kästner SBR, Rohn K, Ohnesorge B. Intermittent positive pressure ventilation with constant positive end-expiratory pressure and alveolar recruitment manoeuvre during inhalation anaesthesia in horses undergoing surgery for colic, and its influence on the early recovery period. Vet Anaesth Analg 2011; 38:169-77. [DOI: 10.1111/j.1467-2995.2011.00606.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Moens YPS. Clinical application of continuous spirometry with a pitot-based flow meter during equine anaesthesia. EQUINE VET EDUC 2010. [DOI: 10.1111/j.2042-3292.2010.00066.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Schauvliege S, Van den Eede A, Duchateau L, Gasthuys F. Cardiovascular effects of enoximone in isoflurane anaesthetized ponies. Vet Anaesth Analg 2007; 34:416-30. [PMID: 17696974 DOI: 10.1111/j.1467-2995.2007.00343.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Enoximone is a phosphodiesterase III inhibitor frequently used to improve cardiac output (CO) in man. As the use of enoximone has not been reported in horses, the effects of this inodilator were examined in isoflurane anaesthetized ponies. STUDY DESIGN Prospective, randomised, experimental study. ANIMALS Six healthy ponies, weighing 286 (212-367) +/- 52 kg, aged 5.0 +/- 1.6 years (4-6.5). METHODS After sedation with romifidine [80 microg kg(-1) intravenously (IV)], general anaesthesia was induced with midazolam (0.06 mg kg(-1) IV) and ketamine (2.2 mg kg(-1) IV) and maintained with isoflurane in oxygen (Et Iso 1.7%). The ponies were ventilated to maintain eucapnia (PaCO(2) 4.66-6.00 kPa). Each pony was anaesthetized twice with an interval of 3 weeks; receiving enoximone 0.5 mg kg(-1) IV (E) or saline (S) 90 minutes post-induction. Heart rate (HR), arterial (AP) and right atrial pressure (RAP) were measured before treatment, every 5 minutes between T0 (treatment) and T30 and then every 10 minutes until T120. Cardiac output measurements (lithium dilution technique) and blood gas analysis (arterial and central venous samples) were performed before T0 and at T5, T10, T20, T40, T60, T80, T100 and T120. Stroke volume (SV), systemic vascular resistance (SVR), venous admixture (Qs/Qt) and oxygen delivery (DO(2)) were calculated. RESULTS Enoximone induced significant increases in HR, CO, SV, Qs/Qt and DO(2) and a significant decrease in RAP. No significant differences were detected for AP, SVR and blood gases. No cardiac arrhythmias or other side effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE The present results suggest that in isoflurane anaesthetized ponies, enoximone has beneficial effects on CO and SV without producing significant changes in blood pressure. Despite an increase in Qs/Qt, DO(2) to the tissues was improved.
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Affiliation(s)
- Stijn Schauvliege
- Department Of Surgery and Anaesthesia of Domestic Animals, University of Ghent, Merelbeke, Belgium.
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THE CARDIOPULMONARY EFFECTS OF ETORPHINE, AZAPERONE, DETOMIDINE, AND BUTORPHANOL IN FIELD-ANESTHETIZED WHITE RHINOCEROSES (CERATOTHERIUM SIMUM). J Zoo Wildl Med 2007; 38:380-7. [DOI: 10.1638/2006-0038r.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Gehlen H, Weichler A, Bubeck K, Ohnesorge B, Deegen E, Stadler P. Effects of Two Different Dosages of Dobutamine on Pulmonary Artery Wedge Pressure, Systemic Arterial Blood Pressure and Heart Rate in Anaesthetized Horses. ACTA ACUST UNITED AC 2006; 53:476-80. [PMID: 17054485 DOI: 10.1111/j.1439-0442.2006.00860.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The purpose of the present study was to investigate the effects of two different dobutamine concentrations on pulmonary artery wedge pressure (PAWP) and on mean systemic arterial blood pressure (MAP) in horses anaesthetized with isoflurane, after induction of general anaesthesia with xylazine, ketamine and diazepam. Eight healthy warm-blood horses were included in the study. Each horse was subjected to general anaesthesia twice with two different dosages of dobutamine, 3 and 5 microg/kg bw/min, being infused over 15 min, starting 50 min after induction of general anaesthesia (T(0)). The heart rate, the PAWP and the MAP were recorded after 10 min (T(1)) and then every 5 min until 15 min after cessation of intravenous dobutamine administration (T(3)-T(5)). The PAWP was measured by a right heart catheter, which was positioned in the pulmonary capillaries. Mean systemic arterial blood pressure was monitored at the facial artery for the duration of general anaesthesia. All parameters increased at both dosage rates of dobutamine and decreased significantly when dobutamine administration ceased. The increase in heart rate was significantly higher after administration of 3 microg/kg bw/min dobutamine compared with the dosage of 5 microg/kg bw/min dobutamine. The increase in MAP was also higher at this dosage, but not significantly different to the dosage of 5 microg/kg bw/min dobutamine. During both dosages the MAP was above a value considered to be compatible with good peripheral circulation. The greater increase in PAWP was observed during administration of 5 g/kg bw/min dobutamine, but PAWP was not significantly different with the dosage of 3 microg/kg bw/min dobutamine. In conclusion, the administration of dobutamine led to an increase in MAP and PAWP above a value considered to be compatible with a good peripheral circulation. The results of the present study indicate that dobutamine improves circulation, in addition to its well-known effect on the periphery.
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Affiliation(s)
- H Gehlen
- Klinik für Pferde, Tierärztliche Hochschule Hannover, Bischofsholer Damm 15, D-30173 HannoverKlinik für Pferde, Tierärztliche Hochschule Hannover, Bischofsholer Damm 15, D-30173 Hannover, Germany.
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Love EJ, Lane JG, Murison PJ. Morphine administration in horses anaesthetized for upper respiratory tract surgery. Vet Anaesth Analg 2006; 33:179-88. [PMID: 16634944 DOI: 10.1111/j.1467-2995.2005.00247.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine the effect of morphine administration on commonly monitored cardio-respiratory variables and recovery quality in horses undergoing anaesthesia and surgery. STUDY DESIGN Prospective, randomized clinical study. ANIMALS Thirty-eight thoroughbred horses, 32 geldings and six mares, 3-13 years old, weighing 411-600 kg. MATERIALS AND METHODS A standard anaesthetic technique was used. Twenty minutes after induction of anaesthesia horses received 0.1 mg kg(-1) (0.1 m) or 0.2 mg kg(-1) (0.2 m) morphine by intravenous injection. A control group did not receive morphine. Heart rate, respiratory rate (fr), mean arterial pressure (MAP) and blood gases were measured before morphine administration and every 10 minutes thereafter. Horses were positioned for 35 minutes in right lateral recumbency for tension palatoplasty by cautery and were then moved into dorsal recumbency for additional intraluminal surgery comprising one or more of aryepiglottic fold resection, sub-epiglottal mucosal resection, ventriculectomy and cordectomy. A subjective recovery score from 0 (worst) to 5 (best) was assigned by a single observer who was unaware of treatment group. Two-way repeated measures anova, one-way anova, Kruskal-Wallis test, Mann-Whitney test, Pearson and Spearman correlation coefficients, and chi-squared tests were used to analyse the data where appropriate. RESULTS Arterial partial pressure of oxygen (PaO(2)) decreased significantly over time and was significantly lower in horses that received morphine. One horse in the control group and two horses in each of the morphine groups had a PaO(2) <13 kPa. No other significant cardiopulmonary effects were detected. Recovery scores [median (range)] were higher in morphine recipients: 4 (2-5) in 0.1 m, 4 (3-5) in 0.2 m compared with 3 (2-4) in the control group. CONCLUSIONS AND CLINICAL RELEVANCE The lower PaO(2) in morphine recipients did not appear to be of clinical significance in healthy horses because the number of horses with a low PaO(2) was similar between groups. The quality of recovery was significantly better in morphine recipients. These results indicate that morphine may be considered for use in clinical cases although further work is required to assess the analgesic properties of the drug in this species.
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Affiliation(s)
- Emma J Love
- Department of Clinical Veterinary Science, University of Bristol, Langford House, Langford, Bristol, UK.
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Brosnan RJ, Steffey EP, LeCouteur RA, Imai A, Farver TB, Kortz GD. Effects of ventilation and isoflurane end-tidal concentration on intracranial and cerebral perfusion pressures in horses. Am J Vet Res 2003; 64:21-5. [PMID: 12518873 DOI: 10.2460/ajvr.2003.64.21] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To measure the effects of isoflurane end-tidal concentration and mode of ventilation (spontaneous vs controlled) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in horses. ANIMAL adult horses of various breeds. PROCEDURES Anesthesia was induced and maintained with isoflurane in O2 in 6 healthy, unmedicated, adult horses. Using a subarachnoid strain gauge transducer, ICP was measured. Blood gas tensions and carotid artery pressures also were measured. Four isoflurane doses were studied, corresponding to the following multiples of the minimum alveolar concentration (MAC): 1.0 MAC, 1.2 MAC, 1.4 MAC, and 1.6 MAC. Data were collected during controlled ventilation and spontaneous ventilation at each dose. RESULTS increasing isoflurane end-tidal concentration induced significant dose-dependent decreases in mean arterial pressure (MAP) and CPP but no change in ICR Hypercapnic spontaneous ventilation caused significant increases in MAP and ICR compared with normocapnic controlled ventilation; no change in CPP was observed. CONCLUSIONS AND CLINICAL RELEVANCE Hypercapnia likely increases cerebral blood flow (CBF) by maintaining CPP in the face of presumed cerebral vasodilation in healthy anesthetized horses. The effect of isoflurane dose on CBF however, remains unresolved because it depends on the opposing influences of a decrease in CCP and cerebral vasodilation.
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Affiliation(s)
- Robert J Brosnan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Abstract
OBJECTIVE This clinical report describes surgical correction of diaphragmatic hernia in three young horses. STUDY DESIGN Retrospective investigation of medical records and subsequent racing performance. ANIMALS Three young horses with diaphragmatic hernia. RESULTS Three young horses with signs of abdominal pain had diaphragmatic hernia causing small intestinal strangulation. The strangulated small intestine was resected and an end-to-end jejuno-jejunal (two horses) or a side-to-side jejuno-cecal anastomosis (one horse) was performed. Diaphragmatic hernias were closed with a continuous suture pattern. All horses recovered and raced. No difference in race records was found between the subject horses and their siblings. One subject horse died of colic at 5 years of age, but the cause of the colic was undetermined. The remaining two horses are in use as broodmares and have produced multiple foals without recurrence of signs of diaphragmatic hernia. CONCLUSIONS Diaphragmatic hernias can be repaired in horses. These horses can achieve race records similar to their siblings and can produce foals without recurrence of signs of diaphragmatic hernia.
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Affiliation(s)
- E M Santschi
- Peterson and Smith Equine Hospital, Ocala, FL, USA
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Moens Y, Lagerweij E, Gootjes P, Poortman J. Distribution of inspired gas to each lung in the anaesthetised horse and influence of body shape. Equine Vet J 1995; 27:110-6. [PMID: 7607142 DOI: 10.1111/j.2042-3306.1995.tb03045.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The distribution of inspired gas to each lung, time constants of the lungs and parameters of gas exchange were studied in 2 groups of horses (mean bwt 606 kg), anaesthetised using thiopentone and chloral hydrate and breathing room air. One group (n = 4) had a downward curved abdominal contour (round-bellied) and the other group (n = 4) had an upward curved abdominal contour (flat-bellied). An equal distribution of inspired gas between the lungs existed in both groups in dorsal recumbency. Flat-bellied horses maintained this equal distribution in lateral recumbency whereas in round-bellied horses an uneven distribution of tidal volume (VT) developed. The percentage of (VT) distributed to the dependent lung was 23% and 38% for left and right lateral recumbency respectively. The distribution of VT agreed with the ratio of time constants of the lungs in flat-bellied horses but differed markedly from this ratio in round-bellied horses suggesting that, in the latter, factors other than compliance and resistance play a role in distribution of ventilation. Round-bellied horses had a lower PaO2 and a larger (A-a)PaO2 than flat-bellied horses in all body positions. The results are compatible with the known hypothesis that pressure exerted by abdominal contents on the dependent lung and diaphragm is an important factor in ventilation/perfusion mismatch of the anaesthetised horse.
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Affiliation(s)
- Y Moens
- Department of Veterinary Anaesthesiology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
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Abstract
The pharmacokinetics of thiopentone sodium administered intravenously as a single dose (11 mg/kg) were studied in acepromazine pre-medicated horses and ponies in which anaesthesia was maintained with either halothane (Group 1) or isoflurane (Group 2). The results showed that the disposition kinetics of thiopentone in horses and ponies were best described by a three-compartment open model. In plasma, a very short initial distribution phase in both horses and ponies, half-life 1.4 +/- 1.2 min (mean +/- SD) and 1.3 +/- 0.7 min, respectively, was obtained, which was followed by a second comparatively slower redistribution phase, half-life 16 +/- 12 min and 11 +/- 5 min, respectively. The volume of distribution for the drug was large, especially in the ponies which received isoflurane (1127 +/- 86 ml/kg), compared to the horses which received halothane (742 +/- 89 ml/kg). The drug had a somewhat shorter elimination half-life in the horses (147 +/- 21 min) than in than ponies (222 +/- 44 min), but no obvious difference in clearance of the drug was observed between the horses (3.5 +/- 0.5 ml/min/kg) and ponies (3.6 +/- 0.8 ml/min/kg).
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Affiliation(s)
- B T Abass
- Department of Veterinary Surgery, University of Bristol, Langford, UK
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Taylor P, Young S. Does the induction agent affect the course of halothane anaesthesia in horses? ACTA ACUST UNITED AC 1993. [DOI: 10.1111/j.1467-2995.1993.tb00122.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Affiliation(s)
- L Nilsfors
- Department of Clinical Radiology, Swedish University of Agricultural Sciences, Uppsala
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Gasthuys F, de Moor A, Parmentier D. Influence of dopamine and dobutamine on the cardiovascular depression during a standard halothane anaesthesia in dorsally recumbent, ventilated ponies. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE A 1991; 38:494-500. [PMID: 1950240 DOI: 10.1111/j.1439-0442.1991.tb01040.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The influence of different rates of dopamine and dobutamine on the cardiovascular depression during a standard halothane anesthesia was studied in dorsally recumbent ventilated ponies. Haemodynamic and respiratory responses were investigated by means of cardiac output (CO) determination (thermodilution technique), mean systemic (MAP) and pulmonary artery pressure (MPAP) (direct intravascular method) and arterial blood analysis (blood gases and packed cell volume). An important cardiopulmonary depression characterized by decreases (55% of the standing values) in CO, cardiac index (CI), MAP, MPAP and other cardiovascular related parameters occurred in the dorsally recumbent anaesthetized ponies after a stabilization period of 30 minutes. Dopamine at 2 different infusion rates (2.5 and 5.0 micrograms/kg/min) induced few changes of the cardiopulmonary parameters (non-significant increases in MAP, CI, left ventricular work [LVW], stroke volume [SV]; non-significant decrease in total peripheral resistance [TPR]). Several minor time related influences were also observed (increases in MPAP and total pulmonary resistance [TpR]). Arterial blood gases did not change during the different dopamine infusions. Low doses of dobutamine (1.25 micrograms/kg/min) were efficient to counteract the cardiovascular depression. Significant increases in CO, CI, MAP, MPAP and SV were observed. TPR and TpR tended to decrease but non-significantly. Heart rate and blood gases remained constant. The higher doses of dobutamine (2.5 and 5.0 micrograms/kg/min) accentuated these changes but a significant increase in heart rate with even periods of severe tachycardia and an increase of the packed cell volume were also observed. Apparently, low doses of dobutamine were indicated for the management of the cardiovascular depression during anaesthesia in the dorsally recumbent ventilated horse.
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Affiliation(s)
- F Gasthuys
- Large Animal Surgical Clinic, State University of Gent, Belgium
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Gasthuys F, de Moor A, Parmentier D. Haemodynamic effects of change in position and respiration mode during a standard halothane anaesthesia in ponies. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE A 1991; 38:203-11. [PMID: 1907066 DOI: 10.1111/j.1439-0442.1991.tb01003.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of change in position and respiration modes were studied in 5 experimental ponies during a standard halothane anaesthesia. A marked cardiovascular depression (decrease in mean arterial blood pressure, cardiac output, stroke volume and left ventricle work) occurred in recumbent, spontaneously breathing ponies. No significant differences were found between right and left lateral recumbency. The most pronounced cardiovascular depression was observed in the dorsal position. Sternal recumbency appeared to be slightly beneficial (higher systemic blood pressure and arterial oxygenation). Peripheral resistance tended to decrease in the lateral positions (peripheral vasodilatation) but increased slightly in dorsally recumbent ponies. The mean pulmonary artery pressure decreased significantly in the dorsal position. Pulmonary resistance increased slightly in the laterally and the sternally positioned ponies, suggesting a pulmonary vasoconstriction. On the other hand, pulmonary resistance decreased in dorsal recumbency. Arterial oxygenation decreased progressively during anaesthesia but remained always above standing control values. Hypoventilation (increase in arterial carbon dioxide to +/- 60 mm Hg) was observed in all positions. Controlled intermittent positive pressure ventilation (I.P.P.V.) induced a further decrease of all cardiovascular parameters although no significant differences in cardiac indexes were found regarding the spontaneous breathing protocol. In ventilated ponies the greatest cardiovascular depression was again observed in dorsal recumbency. Peripheral resistance increased slightly in the sternally positioned ponies. A gradual time-dependent increase in pulmonary resistance was observed. Apparently, the arterial oxygenation improved slightly in all positions (especially the sternal posture) when I.P.P.V. was applied.
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Affiliation(s)
- F Gasthuys
- Large Animal Surgical Clinic, State University of Gent, Belgium
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Abstract
The basis for management of all complications is early recognition, preparation, and a problem-solving approach. Some anesthetic complications, such as equipment malfunction and injuries from endotracheal intubation or misplaced drug injections, are common to all animals and can be prevented almost entirely by careful management. Other problems, such as pulmonary dysfunction and cardiovascular depression, seem to occur more often in healthy horses than in healthy members of other domestic species. Postoperative myopathy-neuropathy, sometimes a devastating complication, seems to be peculiar to the horse, and its incidence has been linked to hypotensive inhalant anesthesia. Careful positioning and padding, monitoring of anesthetic depth, and treating of cardiovascular depression may prevent most cases of postanesthetic myopathy. Idiosyncratic drug reactions, such as MH, are entirely unpredictable and can be rapidly fatal unless recognized early and treated vigorously and specifically.
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Affiliation(s)
- L Klein
- New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square
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Gasthuys F, de Moor A, Parmentier D. Time-related responses to a constant-dose halothane anaesthesia in dorsally recumbent ventilated ponies. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE A 1990; 37:492-8. [PMID: 2123051 DOI: 10.1111/j.1439-0442.1990.tb00935.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Haemodynamic and respiratory responses to halothane were investigated in dorsally recumbent, ventilated ponies during 2 hours. Normocapnia was maintained using intermittent positive pressure ventilation. Compared to the base line values at 30 minutes of constant dose halothane, no significant changes in heart rate, systemic blood pressure, cardiac output, cardiac index, stroke volume and left ventricle work were observed during a 2 hours anaesthesia. Arterial oxygenation increased initially (greater than 300 mm Hg) but tended to decrease non-significantly during the rest of the anaesthesia. Blood temperature decreased significantly during anaesthesia (p less than 0.05 after 30 minutes), probably due to the cold thermodilution injections but also to peripheral losses of body heat. Time-related increases in mean pulmonary artery pressure (p less than 0.05 after 90 minutes), total peripheral and pulmonary resistance (p less than 0.05 after respectively 60 and 90 minutes) were observed. Increases in peripheral and pulmonary resistance probably reflected vasoconstriction of respectively the peripheral and pulmonary vasculature. These changes might be caused by an increase in circulating catecholamines during prolonged anaesthesia. To avoid possible erroneous conclusions the observed time-dependent responses in anaesthetized dorsally recumbent ponies have to be taken in consideration when other influences (e.a. drugs) are investigated during anaesthesia.
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Affiliation(s)
- F Gasthuys
- Large Animal Surgical Clinic, State University of Gent, Belgium
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Abstract
The clinical usefulness of two pulse oximeters was evaluated at two probe sites in nine anesthetized horses. The hemoglobin saturation determined by the pulse oximeters (SaOx) was compared with the hemoglobin saturation calculated from the measured arterial oxygen tension (SaO2). The mean and standard deviation (SD) were calculated from the differences in saturation measurements, over the saturation range of 80% to 100%, for each oximeter used at the tongue probe site and for one oximeter used at the ear. The oximeter results tended to underestimate the SaO2 with mean differences of -3.7% on the tongue and -6.0% on the ear. The limits of agreement were defined as the mean difference +/- 2 SD. Each oximeter used at the tongue produced limits of agreement of +1% to -8%, which meant that 95% of the SaOx values were 1 percentage point above or 8 percentage points below the SaO2. The variability of the differences and limits of agreement were larger when the ear was used as the probe site and at saturations less than 80%. Although both oximeters tended to underestimate the SaO2, they appeared to be clinically useful in detecting changes in arterial hemoglobin saturation.
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Affiliation(s)
- K J Whitehair
- Department of Surgery and Medicine, College of Veterinary Medicine, Kansas State University, Manhattan
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37
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Abstract
Ventilation-perfusion relationships were studied by the multiple inert gas elimination technique in seven horses while they were conscious and during inhalation anaesthesia with halothane. A generally good match between ventilation and perfusion was found in the conscious, standing horse. During anaesthesia a huge shunt developed, ie perfusion of completely unventilated lung regions, both in dorsal and left lateral recumbency and whether the horse was breathing spontaneously or mechanically ventilated. The shunt was significantly greater and the arterial oxygen tension (PaO2) significantly lower in dorsal than in left lateral recumbency. Little or no perfusion of low VA/Q regions was observed during anaesthesia, whether ventilation was spontaneous or mechanical. Positive end-expiratory pressure (PEEP) did not significantly improve PaO2 or reduce the shunt. Selective mechanical ventilation of dependent lung regions with PEEP reduced the shunt markedly, an effect that was not achieved by conventional mechanical ventilation with general PEEP. The findings seem compatible with alveolar collapse during anaesthesia, causing shunt, whereas the absence of clearly low VA/Q regions questions the role of airway closure as the major disturbance of gas exchange.
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Affiliation(s)
- G Nyman
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala
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Moens Y. Arterial-alveolar carbon dioxide tension difference and alveolar dead space in halothane anaesthetised horses. Equine Vet J 1989; 21:282-4. [PMID: 2504578 DOI: 10.1111/j.2042-3306.1989.tb02168.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Arterial-alveolar carbon dioxide tension differences (a-A) PCO2 and alveolar dead space were measured during clinical halothane anaesthesia of 110 horses with the help of continuous infra-red carbon dioxide analysis of expiratory gas. Mean (a-A) PCO2 was 1.6 +/- 0.8 kPa. Alveolar dead space expressed as a percentage of alveolar tidal volume had a mean value of 23 +/- 13 per cent. Influence on (a-A) PCO2 and alveolar dead space of the following variables was tested statistically: age, weight, body position, respiration mode and duration of anaesthesia. (a-A) PCO2 was influenced positively by weight (P less than 0.0001) and adoption of dorsal recumbency (P less than 0.01). Alveolar dead space was influenced positively by weight (P less than 0.0005), adoption of dorsal recumbency (P less than 0.01), intermittent positive pressure ventilation (P less than 0.0001) and duration of anaesthesia (P less than 0.05).
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Affiliation(s)
- Y Moens
- Faculty of Veterinary Medicine, University of Gent, Belgium
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Nyman G, Hedenstierna G. Comparison of conventional and selective mechanical ventilation in the anaesthetized horse. Effects on central circulation and pulmonary gas exchange. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE A 1988; 35:299-314. [PMID: 3135683 DOI: 10.1111/j.1439-0442.1988.tb00039.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Nyman G, Funkquist B, Kvart C. Postural effects on blood gas tension, blood pressure, heart rate, ECG and respiratory rate during prolonged anaesthesia in the horse. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE A 1988; 35:54-62. [PMID: 3128026 DOI: 10.1111/j.1439-0442.1988.tb00006.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Grandy JL, Steffey EP, Miller M. Arterial blood PO2 and PCO2 in horses during early halothane-oxygen anaesthesia. Equine Vet J 1987; 19:314-8. [PMID: 3113935 DOI: 10.1111/j.2042-3306.1987.tb01419.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Arterial blood was collected from 25 clinically normal horses immediately before and serially throughout the first hour of halothane oxygen anaesthesia. Blood was analysed for oxygen and carbon dioxide partial pressure (PaO2, PaCO2). Measurements of inspired oxygen concentration during anaesthesia permitted direct correlation with blood gases. Horses were divided arbitrarily into two groups based on their age: two to seven years, n = 15; over seven years, n = 10. Average (+/- sd) PaO2 and PaCO2 was 14.1 +/- 1.5 kPa (106 +/- 11 mmHg) and 5.9 +/- 0.6 kPa (44.4 +/- 4.4 mmHg) respectively in conscious, young horses and 14.0 +/- 0.7 and 5.8 +/- 0.5 kPa (105 +/- 5 and 43.3 +/- 3.8 mmHg) respectively in conscious older horses. Arterial oxygen tension decreased to 9.3 +/- 1.0 and 8.5 +/- 1.4 kPa (69.6 +/- 7.8 and 63.7 +/- 10.4 mmHg) in young and older air breathing horses respectively immediately following intravenous anaesthetic induction, recumbency and orotracheal intubation. At this time, PaCO2 was 6.5 +/- 0.5 and 6.0 +/- 0.7 kPa (48.7 +/- 3.5 and 45.1 +/- 4.9 mmHg) respectively. By 30 mins after the start of halothane in oxygen (6 litres/min) anaesthesia PaO2 increased to a maximum in both study groups. Arterial PCO2 increased steadily during anaesthesia and 60 mins after induction PaCO2 was 10.5 +/- 2.4 kPa (78.5 +/- 17.8 mmHg) in the younger horses and 9.2 +/- 1.6 kPa (68.8 +/- 11.8 mmHg) in the older horses. During inhalation anaesthesia PaO2 tended to be greater at comparable time periods in the younger horses despite a slightly greater degree of hypoventilation.
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Abstract
Apneic oxygenation was studied in six ponies for 30 minutes, and six horses for 10 minutes. Arterial blood was sampled at regular intervals for measurement of oxygen and carbon dioxide tensions (PaO2 and PaCO2) and calculation of alveolar-arterial oxygen tension difference (PAO2-PaO2). In both groups of animals, PaO2 decreased rapidly during the first 3 minutes of apnea, then more slowly. Although the mean value was above 100 mmHg at 10 minutes, there was considerable inter-animal variability. Before apnea, PAO2-PaO2 was slightly, but not significantly, larger in horses than in ponies and increased in both groups during the first 3 minutes of apnea, after which the increase was slower. There was no significant difference between ponies and horses up to 10 minutes, suggesting that PAO2-PaO2 is independent of body size. In ponies, the PAO2-PaO2 did not change significantly between 10 and 30 minutes. Final PaO2 could not be correlated with initial PaO2 or initial PAO2-PaO2. The rate of rise of PAO2-PaO2 could not be predicted from baseline values. The rate of rise of PaCO2 was similar and fairly constant in ponies and horses, and did not contribute to the rapid initial decrease in PaO2. It appears that apneic oxygenation should not be used in the equine species, since it is impossible to predict in which animals the technique is safe for more than a few minutes.
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Clarke AF. Review of exercise induced pulmonary haemorrhage and its possible relationship with mechanical stress. Equine Vet J 1985; 17:166-72. [PMID: 3908091 DOI: 10.1111/j.2042-3306.1985.tb02460.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Exercise induced pulmonary haemorrhage (EIPH) is a condition of uncertain aetiology. This article reviews the evidence relating to its incidence, clinical findings, radiological observations, histopathology and certain aspects of respiratory physiology. It is proposed that EIPH is primarily caused by mechanical stress in the dorsocaudal region of the lung.
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Abstract
Respiratory dead-space, tidal volume, respiratory rate, blood gases, cardiac output, heart rate and arterial and pulmonary arterial blood pressures were measured in two conscious, trained ponies in the standing position and in left lateral recumbency. The ponies were reluctant to remain lying down for more than about 20 mins but the reason for this did not become apparent. Tidal volume was reduced during recumbency but the respiratory rate increased, tending to maintain the minute volume at about that of the standing animal. Arterial carbon dioxide tension did not change significantly from standing values but the mean arterial oxygen tension values tended to decrease in both ponies during recumbency because of a slight increase in pulmonary venous admixture. Venous admixture in these two laterally recumbent conscious animals was considerably less than previously reported for anaesthetised subjects.
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Kalhoro AB, Rex MA. Observations on the use of glyceryl guaiacolate as an adjunct to general anaesthesia in horses. Aust Vet J 1984; 61:49-53. [PMID: 6732668 DOI: 10.1111/j.1751-0813.1984.tb07191.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Twenty-one horses undergoing clinical surgery and diagnostic procedures received 15% glyceryl guaiacolate followed by a rapid intravenous injection of a thiobarbiturate for induction of anaesthesia. Premedication was with atropine and acepromazine. Induction was smooth and free from problems apart from transient apnoea in some horses. Maintenance of anaesthesia was with oxygen and halothane administered by means of a closed circle system with soda-lime absorber and with the vaporiser out of circuit. During the period immediately following induction, the heart rate increased and the respiratory rate fell. Blood gas estimations were carried out on 6 horses during anaesthesia. These horses showed respiratory acidosis. Arterial blood oxygen tension values were above those reported in conscious horses. Use of glyceryl guaiacolate in this way provides a safe induction and enables transition to a stable maintenance period which is followed by a quiet and uneventful recovery.
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Ear temperatures in the horse during recovery from anesthesia. J Equine Vet Sci 1982. [DOI: 10.1016/s0737-0806(82)80054-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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