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O'Donovan KA, Aarnes TK, Hubbell JA, Parker EM, Mollenkopf D, Lerche P, Ricco Pereira CH, Bini G, Bednarski RM. Risk of anesthesia-related complications in draft horses: a retrospective, single-center analysis. Vet Anaesth Analg 2023; 50:157-162. [PMID: 36577561 DOI: 10.1016/j.vaa.2022.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To report anesthetic-related complications and determine risks associated with anesthesia in draft horses. STUDY DESIGN Retrospective study. ANIMALS A total of 401 anesthetic records for draft horse breeds that underwent general anesthesia from January 2010 through December 2020 were reviewed; horses euthanized during general anesthesia were excluded. METHODS Demographics, perioperative drugs used, procedure type and duration, time to extubation, number of attempts to stand, use of sling in recovery and perioperative morbidity and mortality were investigated. Morbidity and mortality statistical evaluation included univariable logistic regression analysis and ordinal regression analysis. RESULTS American Society of Anesthesiologists (ASA) status I-II, ASA III-V and total mortality rate for all cases was 0.69% (2/288), 6.19% (7/113) and 2.24% (9/401), respectively, with Belgian horses being overrepresented (6/9). Cardiac arrest occurred in six out of nine horses that died without euthanasia, and five out of six of these horses underwent colic surgery. Factors associated with increased mortality risk included ASA status of III-V, increased body weight, emergency status and horses presenting for colic. Hypotension, hypercarbia and hypoxemia occurred in 56% (224/401), 46% (186/401) and 14% (58/401) of horses, respectively. During recovery from anesthesia, lighter horses and horses undergoing shorter anesthetic procedures were more likely to be successful on the first or second attempt to stand and were less likely to require a sling in recovery. CONCLUSIONS AND CLINICAL RELEVANCE Draft horses undergoing general anesthesia had a higher mortality rate than previously reported for all types and breeds of horses.
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Affiliation(s)
- Kathrin A O'Donovan
- The Ohio State University Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA
| | - Turi K Aarnes
- The Ohio State University Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA.
| | | | - Elizabeth M Parker
- The Ohio State University Department of Preventive Medicine, College of Veterinary Medicine, Columbus, OH, USA
| | - Dixie Mollenkopf
- The Ohio State University Department of Preventive Medicine, College of Veterinary Medicine, Columbus, OH, USA
| | - Phillip Lerche
- The Ohio State University Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA
| | - Carolina H Ricco Pereira
- The Ohio State University Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA
| | - Gianluca Bini
- The Ohio State University Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA
| | - Richard M Bednarski
- The Ohio State University Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Columbus, OH, USA
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Dagnall C, Khenissi L, Love E. Monitoring techniques for equine anaesthesia. EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Dagnall
- Faculty of Health Sciences The University of Bristol Bristol UK
| | | | - E. Love
- Faculty of Health Sciences The University of Bristol Bristol UK
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Moreno‐Martinez F, Senior JM, Mosing M. Controlled mechanical ventilation in equine anaesthesia: Classification of ventilators and practical considerations (Part 2). EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- F. Moreno‐Martinez
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
| | - J. M. Senior
- Department of Equine Clinical Science Institute of Veterinary Science University of Liverpool Neston UK
| | - M. Mosing
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
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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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Mosing M, Böhm SH, Rasis A, Hoosgood G, Auer U, Tusman G, Bettschart-Wolfensberger R, Schramel JP. Physiologic Factors Influencing the Arterial-To-End-Tidal CO 2 Difference and the Alveolar Dead Space Fraction in Spontaneously Breathing Anesthetised Horses. Front Vet Sci 2018; 5:58. [PMID: 29644221 PMCID: PMC5882784 DOI: 10.3389/fvets.2018.00058] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/12/2018] [Indexed: 01/21/2023] Open
Abstract
The arterial to end-tidal CO2 difference (P(a-ET)CO2) and alveolar dead space fraction (VDalvfrac = P(a-ET)CO2/PaCO2), are used to estimate Enghoff's "pulmonary dead space" (V/QEng), a factor which is also influenced by venous admixture and other pulmonary perfusion abnormalities and thus is not just a measure of dead space as the name suggests. The aim of this experimental study was to evaluate which factors influence these CO2 indices in anesthetized spontaneously breathing horses. Six healthy adult horses were anesthetized in dorsal recumbency breathing spontaneously for 3 h. Data to calculate the CO2 indices (response variables) and dead space variables were measured every 30 min. Bohr's physiological and alveolar dead space variables, cardiac output (CO), mean pulmonary pressure (MPP), venous admixture [Formula: see text], airway dead space, tidal volume, oxygen consumption, and slope III of the volumetric capnogram were evaluated (explanatory variables). Univariate Pearson correlation was first explored for both CO2 indices before V/QEng and the explanatory variables with rho were reported. Multiple linear regression analysis was performed on P(a-ET)CO2 and VDalvfrac assessing which explanatory variables best explained the variance in each response. The simplest, best-fit model was selected based on the maximum adjusted R2 and smallest Mallow's p (Cp). The R2 of the selected model, representing how much of the variance in the response could be explained by the selected variables, was reported. The highest correlation was found with the alveolar part of V/QEng to alveolar tidal volume ratio for both, P(a-ET)CO2 (r = 0.899) and VDalvfrac (r = 0.938). Venous admixture and CO best explained P(a-ET)CO2 (R2 = 0.752; Cp = 4.372) and VDalvfrac (R2 = 0.711; Cp = 9.915). Adding MPP (P(a-ET)CO2) and airway dead space (VDalvfrac) to the models improved them only marginally. No "real" dead space variables from Bohr's equation contributed to the explanation of the variance of the two CO2 indices. P(a-ET)CO2 and VDalvfrac were closely associated with the alveolar part of V/QEng and as such, were also influenced by variables representing a dysfunctional pulmonary perfusion. Neither P(a-ET)CO2 nor VDalvfrac should be considered pulmonary dead space, but used as global indices of V/Q mismatching under the described conditions.
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Affiliation(s)
- Martina Mosing
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Stephan H Böhm
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Anthea Rasis
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Giselle Hoosgood
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Ulrike Auer
- Anaesthesiology and Perioperative Intensive Care Medicine, Veterinary University Vienna, Vienna, Austria
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | | | - Johannes P Schramel
- Anaesthesiology and Perioperative Intensive Care Medicine, Veterinary University Vienna, Vienna, Austria
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ACCURACY OF NONINVASIVE ANESTHETIC MONITORING IN THE ANESTHETIZED GIRAFFE (GIRAFFA CAMELOPARDALIS). J Zoo Wildl Med 2017; 48:609-615. [DOI: 10.1638/2016-0276.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Review of hypoxaemia in anaesthetized horses: predisposing factors, consequences and management. Vet Anaesth Analg 2017; 44:397-408. [DOI: 10.1016/j.vaa.2016.06.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 05/18/2016] [Accepted: 06/02/2016] [Indexed: 11/24/2022]
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Fahlman Å, Edner A, Wenger S, Foggin C, Nyman G. Pulmonary gas exchange and acid-base status during immobilisation of black rhinoceroses (<i>Diceros bicornis</i>) in Zimbabwe. J S Afr Vet Assoc 2016; 87:e1-e9. [PMID: 28155294 PMCID: PMC6138189 DOI: 10.4102/jsava.v87i1.1328] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 04/29/2016] [Accepted: 08/18/2016] [Indexed: 11/18/2022] Open
Abstract
When immobilising wildlife, adverse side effects can include hypoxaemia, acidosis and hypertension. Pulmonary gas exchange and acid–base status were evaluated during immobilisation of 25 free-ranging and one boma-held black rhinoceros (Diceros bicornis) in Zimbabwe. The effect of different body positions on arterial oxygenation was evaluated. A combination of the following drugs was used: an opioid (etorphine or thiafentanil), azaperone and an α2-adrenoceptor agonist (detomidine or xylazine). Respiratory and heart rates, rectal temperature and pulse oximetry–derived haemoglobin oxygen saturation were recorded. Serial arterial blood samples were analysed immediately in the field. Marked hypoxaemia and hypercapnia were recorded in immobilised free-ranging black rhinoceroses. Arterial oxygenation was higher during sternal compared to lateral recumbency. Most rhinoceroses developed acidaemia of respiratory and metabolic origin. Initially high lactate concentrations in free-ranging rhinoceroses decreased during immobilisation. Pulse oximetry was unreliable in the detection of hypoxaemia. Positioning in sternal recumbency and routine use of oxygen supplementation are recommended in the management of immobilised rhinoceroses as measures to improve arterial oxygenation.
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Affiliation(s)
- Åsa Fahlman
- Department of Clinical Sciences, Swedish University of Agricultural Sciences.
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Duke T, Cruz AM, Cruz JI, Howden KJ. Cardiopulmonary effects associated with head-down position in halothane-anesthetized ponies with or without capnoperitoneum. Vet Anaesth Analg 2016; 29:76-89. [PMID: 28404303 DOI: 10.1046/j.1467-2995.2002.00077.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2000] [Accepted: 06/29/2001] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare the cardiopulmonary effects of the head-down position, with or without capnoperitoneum, in halothane-anesthetized horses. STUDY DESIGN Prospective randomized study. ANIMALS Five ponies (four mares, one stallion; bodyweight 302 ± 38.4 kg [mean ± SD]) were used. METHODS The ponies were anesthetized with xylazine, guiafenesin, ketamine, and maintained with halothane/oxygen and lungs were ventilated to 40 ± 2 mm Hg (5.3 ± 0.3 kPa) end-tidal CO2 tension. After baseline cardiopulmonary measurements, ponies were kept in horizontal position for 30 minutes, then tilted head-down 30° to the horizontal position for 60 minutes, and then returned to a horizontal position for final measurements. Capnoperitoneum (intra-abdominal pressure: 12 mm Hg [1.6 kPa]) was introduced after baseline cardiopulmonary measurements, until 5 minutes before the final measurements (treatment INS). Ponies in the control treatment (CON) did not receive capnoperitoneum. Cardiopulmonary data were collected every 10 minutes following the baseline measurements until recovery. RESULTS In the head-down position, in both treatments, significant decreases were observed in PaO2, and significant increases were observed in PaCO2, right atrial blood pressure, arterial to end-tidal CO2 gradient, calculated Vd/Vt and Q˙s/Q˙t ratios. During the head-down position, in CON there was decreased cardiac index, and in INS, there were decreases in arterial plasma pH and increases in mean systemic arterial and airway pressures. Treatment INS developed ventilation-perfusion mismatch earlier in the study, and had longer recovery times compared to CON. CONCLUSION Cardiac index and systemic blood pressure appeared to be preserved in INS during the head-down position, but ventilation-perfusion mismatch appeared earlier with head-down position and capnoperitoneum. CLINICAL RELEVANCE Healthy ponies tolerate capnoperitoneum at 12 mm Hg (1.6 kPa) intra-abdominal pressure when tilted head down 30° to the horizontal position.
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Affiliation(s)
- Tanya Duke
- Department of Veterinary Anesthesiology, Radiology and Surgery, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Antonio M Cruz
- Department of Veterinary Anesthesiology, Radiology and Surgery, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - J Ignacio Cruz
- Department of Veterinary Anesthesiology, Radiology and Surgery, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Krista J Howden
- Department of Veterinary Anesthesiology, Radiology and Surgery, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Musk GC, Kemp MW. Maternal and fetal arterial blood gas data during general anaesthesia for caesarean delivery of preterm twin lambs. Lab Anim 2015. [PMID: 26219550 DOI: 10.1177/0023677215598449] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Much remains to be understood with regards the effects of prolonged anaesthesia on maternal and fetal haemodynamics and oxygenation. With the aim of improving anaesthetic management of pregnant sheep undergoing recovery surgery under anaesthesia, paired maternal and fetal arterial blood samples were collected during caesarean delivery of twin preterm lambs to document the blood gas status of the ewe and fetus. Twenty-one Merino twin pregnant ewes at 126 (±1) days of gestation were anaesthetized for caesarean delivery of their fetuses. Arterial blood samples were collected from the radial artery of the ewe and umbilical artery of the fetus at the point of delivery. There was a significant difference between maternal PaCO2 and end-tidal CO2 and alveolar and arterial PaO2, indicating ventilation perfusion mismatch. Interestingly, the ewes were anaemic but the fetuses were not. These data underscore the need to undertake further work to determine the optimal anaesthetic regimen for twin pregnant ewes at different gestational ages in a biomedical research setting.
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Affiliation(s)
- G C Musk
- College of Veterinary Medicine, School of Veterinary and Life Sciences, Murdoch University, Western Australia Animal Care Services, University of Western Australia, Perth, Western Australia
| | - M W Kemp
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia
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Gozalo-Marcilla M, Hopster K, Gasthuys F, Krajewski AE, Schwarz A, Schauvliege S. Minimum end-tidal sevoflurane concentration necessary to prevent movement during a constant rate infusion of morphine, or morphine plus dexmedetomidine in ponies. Vet Anaesth Analg 2014; 41:212-9. [DOI: 10.1111/vaa.12090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 03/25/2013] [Indexed: 12/01/2022]
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12
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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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Franci P, Bertamini A, Bertamini O, Pilla T, Busetto R. Clinical evaluation of an end-tidal target-controlled infusion closed-loop system for isoflurane administration in horses undergoing surgical procedures. Vet J 2012; 192:206-11. [DOI: 10.1016/j.tvjl.2011.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 05/23/2011] [Accepted: 06/01/2011] [Indexed: 11/27/2022]
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Marcilla MG, Schauvliege S, Segaert S, Duchateau L, Gasthuys F. Influence of a constant rate infusion of dexmedetomidine on cardiopulmonary function and recovery quality in isoflurane anaesthetized horses. Vet Anaesth Analg 2012; 39:49-58. [DOI: 10.1111/j.1467-2995.2011.00672.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Marcilla MG, Schauvliege S, Duchateau L, Gasthuys F. Cardiopulmonary effects of two constant rate infusions of dexmedetomidine in isoflurane anaesthetized ponies. Vet Anaesth Analg 2010; 37:311-21. [DOI: 10.1111/j.1467-2995.2010.00537.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Rainger JE, Dart CM, Perkins NR. Factors affecting the relationship between arterial and end-tidal carbon dioxide pressures in the anaesthetised horse. Aust Vet J 2010; 88:13-9. [PMID: 20148820 DOI: 10.1111/j.1751-0813.2009.00535.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To assess the effects of the duration of anaesthesia, position of recumbency, mode of ventilation, anaesthetic drug protocol, patient age and type of surgical procedure on the usefulness of capnometry as a measure of the partial pressure of arterial carbon dioxide (P(a)co(2)) during general anaesthesia in horses. DESIGN A prospective study compared the P(a)co(2) values with those of partial pressure of end-tidal carbon dioxide (ETco(2)) in horses anaesthetised for elective or emergency surgical procedures. The difference between P(a)co(2) and ETco(2) (P(a)co(2)- ETco(2)) and the physiological dead space to tidal volume ratio (V(D)/V(T)) were calculated. The effects of the study parameters on these variables was determined. RESULTS The agreement between P(a)co(2) and ETco(2) was poor. P(a)co(2)- ETco(2) and V(D)/V(T) during the first 60 min of anaesthesia was significantly less than after 60 min of anaesthesia. Mode of ventilation, position of recumbency, anaesthetic drug protocol, patient age and type of procedure did not have a significant affect on either value. CONCLUSIONS P(a)co(2)- ETco(2) in anaesthetised horses can be large, making ETco(2) unreliable as a predictor of P(a)co(2) and for assessment of pulmonary ventilation. For anaesthesia lasting less than 60 min at least one blood gas analysis of an arterial blood sample is required to assess P(a)co(2)- ETco(2). Arterial blood gas analysis should be repeated after 60 min of general anaesthesia.
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Affiliation(s)
- J E Rainger
- University Veterinary Teaching Hospital Camden, University of Sydney, Camden, New South Wales 2570, Australia.
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Larenza MP, Ringer SK, Kutter APN, Conrot A, Theurillat R, Kummer M, Thormann W, Bettschart-Wolfensberger R. Evaluation of anesthesia recovery quality after low-dose racemic or S-ketamine infusions during anesthesia with isoflurane in horses. Am J Vet Res 2009; 70:710-8. [DOI: 10.2460/ajvr.70.6.710] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mansel JC, Clutton RE. The influence of body mass and thoracic dimensions on arterial oxygenation in anaesthetized horses and ponies. Vet Anaesth Analg 2008; 35:392-9. [DOI: 10.1111/j.1467-2995.2008.00400.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Neto FJ, Luna SP, Massone F, Thomassian A, Vargas JL, Junior JR, D'Utra Vaz BB, Crocci AJ. The effect of changing the mode of ventilation on the arterial-to-end-tidal CO2 difference and physiological dead space in laterally and dorsally recumbent horses during halothane anesthesia. Vet Surg 2000; 29:200-5. [PMID: 10730713 DOI: 10.1111/j.1532-950x.2000.00200.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the effect of changing the mode of ventilation from spontaneous to controlled on the arterial-to-end-tidal CO2 difference [P(a-ET)CO2] and physiological dead space (VD(phys)/VT) in laterally and dorsally recumbent halothane-anesthetized horses. STUDY DESIGN; Prospective, experimental, nonrandomized trial. ANIMALS Seven mixed breed adult horses (1 male and 6 female) weighing 320 +/- 11 kg. METHODS Horses were anesthetized in 2 positions-right lateral and dorsal recumbency-with a minimum interval of 1 month. Anesthesia was maintained with halothane in oxygen for 180 minutes. Spontaneous ventilation (SV) was used for 90 minutes followed by 90 minutes of controlled ventilation (CV). The same ventilator settings were used for both laterally and dorsally recumbent horses. Arterial blood gas analysis was performed every 30 minutes during anesthesia. End-tidal CO2 (PETCO2) was measured continuously. P(a-ET)CO2 and VD(phys)NT were calculated. Statistical analysis included analysis of variance for repeated measures over time, followed by Student-Newman-Keuls test. Comparison between groups was performed using a paired t test; P < .05 was considered significant. RESULTS P(a-ET)CO2 and VD(phys)/VT increased during SV, whereas CV reduced these variables. The variables did not change significantly throughout mechanical ventilation in either group. Dorsally recumbent horses showed greater P(a-ET)CO2 and VD(phys)/VT values throughout. PaCO2 was greater during CV in dorsally positioned horses. CONCLUSIONS AND CLINICAL RELEVANCE Changing the mode of ventilation from spontaneous to controlled was effective in reducing P(a-ET)CO2 and physiological dead space in both laterally and dorsally recumbent halothane-anesthetized horses. Dorsal recumbency resulted in greater impairment of effective ventilation. Capnometry has a limited value for accurate estimation of PaCO2 in anesthetized horses, although it may be used to evaluate pulmonary function when paired with arterial blood gas analysis.
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Affiliation(s)
- F J Neto
- Department of Veterinary Surgery and Anesthesiology, Faculty of Veterinary Medicine and Animal Science, University of São Paulo State, Botucatu, Brazil
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Donaldson LL, Dunlop GS, Holland MS, Burton BA. The recovery of horses from inhalant anesthesia: a comparison of halothane and isoflurane. Vet Surg 2000; 29:92-101. [PMID: 10653499 DOI: 10.1111/j.1532-950x.2000.00092.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Recovery is one of the more precarious phases of equine general anesthesia. The quality and rate of recovery of horses from halothane and isoflurane anesthesia were compared to determine differences in the characteristics of emergence from these commonly used inhalant anesthetics. EXPERIMENTAL DESIGN Prospective, randomized blinded clinical trial. SAMPLE POPULATION A total of 96 Thoroughbred and 3 Standardbred racehorses admitted for elective distal forelimb arthroscopy. METHODS All horses were premedicated with intravenous xylazine, induced with guaifenesin and ketamine, and maintained on a large animal circle system fitted with an out of the circle, agent specific vaporizer. Recoveries were managed by a blinded scorer with a standardized protocol. A 10 category scoring system was used to assess each horse's overall attitude, purposeful activity, muscle coordination, strength and balance from the time of arrival in recovery to standing. Times to extubation, sternal recumbency and standing were recorded. Median recovery scores and mean times to extubation, sternal and standing were compared using the Mann-Whitney U test and student's t test, respectively. RESULTS The median score for horses recovering from halothane was lower (20.0; range, 10 to 57) than that for horses recovering from isoflurane (27.5; range, 10 to 55). Horses in the two groups were extubated at similar mean times (halothane, 11.3 +/- 5.5 and isoflurane, 9.5 +/- 5.2 minutes) but horses recovering from isoflurane achieved sternal recumbency (halothane, 37.7 +/- 12.1 and isoflurane, 24.7 +/- 8.8 minutes) and stood (halothane, 40.6 +/- 12.9 and isoflurane, 27.6 +/- 9.6 minutes) sooner than those recovering from halothane. CONCLUSIONS The recovery of horses from isoflurane anesthesia was more rapid but less composed than that from halothane. CLINICAL RELEVANCE The quality of recovery following isoflurane was worse than after halothane anesthesia using the criteria chosen for this study. However, the range of recovery scores was similar for both groups and all horses recovered without significant injury.
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Affiliation(s)
- L L Donaldson
- Marion duPont Scott Equine Medical Center, Virginia-Maryland Regional College of Veterinary Medicine, Leesburg 20177, USA
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Donaldson LL, Trostle SS, White NA. Cardiopulmonary changes associated with abdominal insufflation of carbon dioxide in mechanically ventilated, dorsally recumbent, halothane anaesthetised horses. Equine Vet J 1998; 30:144-51. [PMID: 9535071 DOI: 10.1111/j.2042-3306.1998.tb04474.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The use of laparoscopy for the diagnosis or therapeutic management of abdominal disease in the horse has distinct advantages when it allows the horse to remain standing. However, distending the abdomen by insufflation of a biologically active gas in an anaesthetised horse may add to the physiological challenge of general anaesthesia and recumbency. The cardiopulmonary responses to abdominal insufflation with carbon dioxide (CO2) to 15 mmHg pressure were evaluated in 6 horses in dorsal recumbency anaesthetised with halothane in oxygen and subjected to laparoscopic colopexy. Vaporiser settings targeted a fractional expired halothane of 1.5 MAC and a clinically acceptable depth of anaesthesia. Pressure and rate controlled positive pressure ventilation was adjusted to an ETCO2 of 35 mmHg before abdominal insufflation and was not changed thereafter. Cardiopulmonary data were collected before, at 30 and 60 min during and 30 min after CO2 insufflation. ANOVA for repeated measures followed by Tukey's protected t test were used to determine differences. Partial pressure of oxygen and pH of arterial blood, tidal volume and systemic vascular resistance decreased during abdominal insufflation and laparoscopic surgery whereas mean arterial blood pressure, right atrial pressure, cardiac index, stroke index, partial pressure of CO2 in arterial blood and end tidal respiratory gases, and calculated physiological shunt increased significantly. Only systemic vascular resistance returned to the pre-insufflation level after desufflation. The hypercapnia, acidosis and apparent increase in cardiac work that accompany CO2 pneumoperitoneum for laparoscopic surgery could place the anaesthetised horse at additional risk of perioperative complications.
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Affiliation(s)
- L L Donaldson
- Marion duPont Scott Equine Medical Center, Virginia-Maryland, Regional College of Veterinary Medicine, Leesburg 20177, 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
Doxapram, 0.05 mg/kg bodyweight/min, was infused during the second hour of 2 h halothane anaesthesia in six ponies. Two of the ponies were anaesthetised on a second occasion as controls and given 5 per cent dextrose in place of the doxapram. Respiratory depression typical of halothane anaesthesia in ponies developed in the first hour of anaesthesia and continued during the second hour in the control animals. During doxapram infusion arterial carbon dioxide tension decreased and pH increased. Arterial blood pressure increased but there was no change in pulse rate, the electrocardiogram or arterial oxygen tension. Anaesthesia lightened during doxapram infusion necessitating an increase in the vapouriser setting in order to prevent arousal. Recovery from anaesthesia appeared unaffected by the doxapram infusion.
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