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Ketamine-guaiphenesin infusion to supplement halothane anaesthesia in horses
Veterinary Anaesthesia and Analgesia, 2000, 27, 54–62
MEETING ABSTRACTS
Proceedings of the Association of Veterinary Anaesthetists, Madrid, 23–24 September 1999
Comparison between isoflurane and sevoflurane anaesthesia in dogs AG Cantalapiedra, F Laredo, B Villanueva and JL Pereira Hospital Veterinario Rof Codina, Unidad de Cirugı´a, Facultad de Veterinaria de Lugo, 27002-Lugo, Spain This study compared mask induction, maintenance and recovery characteristics of sevoflurane (SEVO) anaesthesia with isoflurane (ISO) in dogs. Six Beagles, three males and three females, were studied. Pre-anaesthetic medication was buprenorphine (0.01 mg kg−1) and acepromazine (0.03 mg kg−1) IM. In a random order, dogs were mask-induced with ISO or SEVO (2.5 MAC) in oxygen (6 L min−1) using a Bain circuit. Tracheae were intubated and anaesthesia maintained with the same agent at 1.5 MAC for 60 minutes. The time to tracheal intubation was recorded. Heart rate, RR, MAP, DAP, FE?CO2, SpO2 and body temperature were measured at intubation (t0) and then every 5 minutes. Arterial pH, PaO2 and PaCO2 were measured every 20 minutes. Arterial blood pressure was recorded directly from the dorsal metatarsal artery and samples withdrawn for gas analysis (Radiometer ABL 500). Inspired, FE?ISO and FE?SEVO were measured continously using a calibrated infra-red analyser (Dra¨ger PM 8050). The same analyser was used to determine FE?CO2, VT and SpO2. Tracheae were extubated when a spontaneous swallow was observed. The times to achieve sternal recumbency and standing were recorded, and dogs were not assisted during recovery. Data, reported as mean 2 SD, were compared over time and between drug groups, using two-way ANOVA. Friedman repeated measures ANOVA was used for nonparametric data. Where statistical significance was detected, a Tukey’s post test (p ³ 0.05) was used. Sevoflurane induction resulted in a significantly shorter time to tracheal intubation than ISO induction and both agents produced a rapid and smooth recovery: time (minutes) to induction ISO 3.35 2 1.27 versus 1.52 2 0.31 SEVO; time to extubation ISO 7.75 2 2.31 versus 8.64 2 1.09 SEVO; time to standing ISO 9.73 2 1.57 versus 11.63 2 2.31 SEVO. Respiratory rate, DAP, SpO2, pH, body temperature and PaO2 did not show significant differences (p × 0.05) at any time between ISO and SEVO
Correspondence: Dr Karen Blissitt, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Veterinary Centre, Easter Bush, Roslin, Midlothian EH25 9RG, UK 54
groups. The PaCO2 and FE?CO2 were significantly higher (p ³ 0.05) in the ISO group, respectively, at 0 and 20 minutes and at 0, 15 and 20 minutes. Values for SAP and MAP were significantly higher (p ³ 0.05) at 40 minutes, and MAP was still increased at 45 minutes of anaesthesia. Heart rate was significantly higher in the ISO group versus the SEVO group from 20 to 60 minutes of anaesthesia. Sevoflurane mask induction is faster compared with isoflurane in adult dogs. Recovery times are comparable in both groups. Sevoflurane produced more cardiovascular depression than isoflurane while isoflurane induced more respiratory depression than sevoflurane.
Ketamine-guaiphenesin infusion to supplement halothane anaesthesia in horses C Spadavecchia, F Stucki and U Schatzmann Klinik fu¨r Nutztiere und Pferde, Universita¨t Bern, Switzerland Halothane produces a concentration related depression of cardiopulmonary function in horses (Steffey and Howland 1978). This study evaluated an infusion of ketamine and guaiphenesin in horses to reduce halothane requirements during surgical anaesthesia. Twenty-three horses (538 [range 330–655] kg, 6 [range 2–18] years old) were anaesthetized for elective (5 soft tissue, 6 major orthopedic) and emergency (4 colic, 2 multiple injury repair) surgery or diagnostic (6) procedures. Pre-anaesthetic medication was xylazine (0.4 mg kg−1) and L-methadone (0.05 mg kg−1) IV. Anaesthesia was induced with guaiphenesin (60 mg kg−1) and ketamine (2.2 mg kg−1) and maintained with halothane (FE?HAL 0.61 2 0.05%) in oxygen. Horses were intubated and breathed spontaneously from a semiclosed anaesthetic circle system. Surgical anaesthesia was achieved with the supplemental continuous infusion of guaiphenesin (150 mg ml−1) and ketamine (6 mg ml−1). Clinical signs of anaesthetic depth, cardiac activity, respiratory rate, arterial blood pressure, FiO2, FE?CO2 and infusion rates were continuously monitored. Respiratory gases were sampled at the distal end of the endotracheal tube (Compact, Datex, Finland). Blood gases were analysed at 20-minute intervals. The recovery was assisted and its quality scored from excellent to bad (five categories). The times to swallowing, sternal recumbency and standing were recorded. Data are presented as the median and range. Data obtained 5 minutes post-induction
Proceedings of the Association of Veterinary Anaesthetists Meeting, Madrid, 1999
and changes in the variables over time were compared with Kruskal–Wallis tests. Surgical anaesthesia was achieved in all horses for the required times (85 [range 35–275] minutes). The initial infusion was set at 0.5 mL kg−1 h−1 and then diminished according to the patient’s requirements. There were no significant changes in the monitored variables over time. The median infusion rate was 32.1 [range 20–50] mg kg−1 min−1 ketamine and 0.8 [range 0.5–1.2] mg kg−1 min−1 guaiphenesin. Systolic, diastolic and mean arterial blood pressures were, respectively, 111 [range 80–174], 67 [range 40–139] and 78 [range 54–151] mm Hg. End expired CO2 was 55 [range 30–66] mm Hg, PaCO2, PaO2 and pH were, respectively: 58 [range 36–75] mm Hg, 254 [range 87–415] mm Hg and 7.28 [range 7.21–7.46]. The recovery times were: swallowing 4.5 [range 1–45] minutes, sternal 15.5 [range 10–60] minutes, standing 27 [range 12–105] minutes. The quality of recovery was judged to be poor in two, good in 13 and excellent in nine horses. No recoveries were judged very poor or bad. The infusion of ketamine-guaiphenesin in horses receiving a subanaesthetic dose of halothane appeared to be a safe method to obtain surgical anaesthesia.
most reliable guides to changing anaesthetic dose were changes in magnitude of PaCO2, eyelid aperture, pupil diameter and mean arterial pressure. As the dose of SEVO increased from MAC to 1.75 MAC, PaCO2 increased from 59 2 9 to 92 2 9 mm Hg; eyelid aperture increased from 3.11 2 0.77 to 4.16 2 0.47 mm and pupil diameter from 1.63 2 0.68 to 3.95 2 1.01 mm. Mean arterial pressure decreased from 103 2 5 to 68 2 5 mm Hg. All changes were significant, p ³ 0.05. Both respiratory frequency and heart rate only tended to decrease (p × 0.05) with increasing SEVO concentration (changes were less dose-predictable). Increasing PaCO2, eyelid aperture and pupil diameter, and decreasing mean arterial pressure are consistent clinical indicators of increasing SEVO dose in surgically unstimulated rats.
Influence of sevoflurane and desflurane anaesthesia on blood biochemical values in horses EP Steffey, F Galey, KR Mama and B Puschner University of California, Davis, CA and Colorado State University, Fort Collins, CO, USA
Clinical signs which indicate varying anaesthetic dose, have been reported for spontaneously breathing rats anaesthetized with halothane and isoflurane. This report provides similarly derived data for sevoflurane (SEVO). Eight healthy, male Sprague-Dawley rats, weighing 473 2 24 [mean 2 SD] gm were studied. Individuals, fasted of food but not water, were placed in a chamber filled with SEVO and O2. Following anaesthetic induction and orotracheal intubation (14 gauge IV catheter), SEVO was delivered via a Bain nonrebreathing circuit. The SEVO MAC was determined for each rat using the standard tail-clamp technique. End-tidal gas was collected manually from a special breathing circuit-endotracheal tube adapter and measured via a calibrated infra-red analyser. Four MAC multiples (1.0, 1.25, 1.5, 1.75) were calculated from the individually determined MAC. The order of anaesthetic dose exposure was randomly determined. Each animal was then further instrumented and measurements were made at each of the four MAC multiples after at least 15 minutes of dose stabilization. Data were evaluated by repeated measures ANOVA and Tukey’s tests. The SEVO MAC for these rats was 2.99 2 0.07%. The
The potential toxicity to horses of sevoflurane (SEVO) or desflurane (DES) anaesthesia was evaluated in two groups of five horses anaesthetized under laboratory conditions with only the drug of interest. Anaesthetic conditions for each horse included both spontaneous and controlled ventilation and end-tidal anaesthetic concentrations of 1.0–1.75 MAC. Venous blood was taken within 1 hour of the anaesthetic induction, at 2 hours of anaesthesia, at the end of anaesthesia, and at 1 hour, 1 and 2 days post-anaesthesia for fluoride (F) analysis (ion-specific electrode). Similarly, blood was obtained before and at 1 hour, 1, 2, and 4 days post-anaesthesia for analysis of serum creatinine (CREAT), urea nitrogen (BUN), aspartate aminotransferase (AST) and sorbitol dehydrogenase (SDH) (analyses by our Veterinary Medical Teaching Hospital). Data were grouped (mean 2 SD) and statistically evaluated with repeated measures ANOVA and Bonferroni tests. A value of p ³ 0.05 was considered to be statistically significant. During 5.2 2 0.2 and 5.3 2 0.2 hours of SEVO and DES anaesthesia, respectively, horses were exposed to 7.0 2 0.3 MAC hours of SEVO and 7.3 2 0.3 MAC hours of DES. Results from pre-anaesthetic blood samples were normal. The serum F concentration significantly increased during SEVO but not during DES anaesthesia. Peak F concentration occurred at the end of anaesthesia and reached 50.8 2 7.1 mM L−1, a commonly reported threshold value for kidney damage in rats. Similarly, CREAT reached its greatest value at 1 hour post-SEVO (2.0 2 0.8 mg dL−1; p ³ 0.05), but this is similar to results with other inhalation anaesthetics, including DES. The BUN did not change with either agent. Sorbitol dehydrogenase increased from control values of 4.2 2 0.7 and 4.4 2 0.4 to 10.2 2 1.8 and 16.0 2 2.8 IU L−1 at 1 hour post-anaesthesia for SEVO and
Veterinary Anaesthesia and Analgesia, 2000, 27, 54–62
55
References Steffey EP, Howland D Jr (1978) Cardiovascular effects of halothane in the horse. Am J Vet Res 39, 611–615.
Clinical signs of sevoflurane anaesthesia in spontaneously breathing rats MA Steffey, R Brosnan and EP Steffey Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
Copyright of Veterinary Anaesthesia & Analgesia is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
MEETING ABSTRACTS
Proceedings of the Association of Veterinary Anaesthetists, Madrid, 23–24 September 1999
Comparison between isoflurane and sevoflurane anaesthesia in dogs AG Cantalapiedra, F Laredo, B Villanueva and JL Pereira Hospital Veterinario Rof Codina, Unidad de Cirugı´a, Facultad de Veterinaria de Lugo, 27002-Lugo, Spain This study compared mask induction, maintenance and recovery characteristics of sevoflurane (SEVO) anaesthesia with isoflurane (ISO) in dogs. Six Beagles, three males and three females, were studied. Pre-anaesthetic medication was buprenorphine (0.01 mg kg−1) and acepromazine (0.03 mg kg−1) IM. In a random order, dogs were mask-induced with ISO or SEVO (2.5 MAC) in oxygen (6 L min−1) using a Bain circuit. Tracheae were intubated and anaesthesia maintained with the same agent at 1.5 MAC for 60 minutes. The time to tracheal intubation was recorded. Heart rate, RR, MAP, DAP, FE?CO2, SpO2 and body temperature were measured at intubation (t0) and then every 5 minutes. Arterial pH, PaO2 and PaCO2 were measured every 20 minutes. Arterial blood pressure was recorded directly from the dorsal metatarsal artery and samples withdrawn for gas analysis (Radiometer ABL 500). Inspired, FE?ISO and FE?SEVO were measured continously using a calibrated infra-red analyser (Dra¨ger PM 8050). The same analyser was used to determine FE?CO2, VT and SpO2. Tracheae were extubated when a spontaneous swallow was observed. The times to achieve sternal recumbency and standing were recorded, and dogs were not assisted during recovery. Data, reported as mean 2 SD, were compared over time and between drug groups, using two-way ANOVA. Friedman repeated measures ANOVA was used for nonparametric data. Where statistical significance was detected, a Tukey’s post test (p ³ 0.05) was used. Sevoflurane induction resulted in a significantly shorter time to tracheal intubation than ISO induction and both agents produced a rapid and smooth recovery: time (minutes) to induction ISO 3.35 2 1.27 versus 1.52 2 0.31 SEVO; time to extubation ISO 7.75 2 2.31 versus 8.64 2 1.09 SEVO; time to standing ISO 9.73 2 1.57 versus 11.63 2 2.31 SEVO. Respiratory rate, DAP, SpO2, pH, body temperature and PaO2 did not show significant differences (p × 0.05) at any time between ISO and SEVO
Correspondence: Dr Karen Blissitt, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Veterinary Centre, Easter Bush, Roslin, Midlothian EH25 9RG, UK 54
groups. The PaCO2 and FE?CO2 were significantly higher (p ³ 0.05) in the ISO group, respectively, at 0 and 20 minutes and at 0, 15 and 20 minutes. Values for SAP and MAP were significantly higher (p ³ 0.05) at 40 minutes, and MAP was still increased at 45 minutes of anaesthesia. Heart rate was significantly higher in the ISO group versus the SEVO group from 20 to 60 minutes of anaesthesia. Sevoflurane mask induction is faster compared with isoflurane in adult dogs. Recovery times are comparable in both groups. Sevoflurane produced more cardiovascular depression than isoflurane while isoflurane induced more respiratory depression than sevoflurane.
Ketamine-guaiphenesin infusion to supplement halothane anaesthesia in horses C Spadavecchia, F Stucki and U Schatzmann Klinik fu¨r Nutztiere und Pferde, Universita¨t Bern, Switzerland Halothane produces a concentration related depression of cardiopulmonary function in horses (Steffey and Howland 1978). This study evaluated an infusion of ketamine and guaiphenesin in horses to reduce halothane requirements during surgical anaesthesia. Twenty-three horses (538 [range 330–655] kg, 6 [range 2–18] years old) were anaesthetized for elective (5 soft tissue, 6 major orthopedic) and emergency (4 colic, 2 multiple injury repair) surgery or diagnostic (6) procedures. Pre-anaesthetic medication was xylazine (0.4 mg kg−1) and L-methadone (0.05 mg kg−1) IV. Anaesthesia was induced with guaiphenesin (60 mg kg−1) and ketamine (2.2 mg kg−1) and maintained with halothane (FE?HAL 0.61 2 0.05%) in oxygen. Horses were intubated and breathed spontaneously from a semiclosed anaesthetic circle system. Surgical anaesthesia was achieved with the supplemental continuous infusion of guaiphenesin (150 mg ml−1) and ketamine (6 mg ml−1). Clinical signs of anaesthetic depth, cardiac activity, respiratory rate, arterial blood pressure, FiO2, FE?CO2 and infusion rates were continuously monitored. Respiratory gases were sampled at the distal end of the endotracheal tube (Compact, Datex, Finland). Blood gases were analysed at 20-minute intervals. The recovery was assisted and its quality scored from excellent to bad (five categories). The times to swallowing, sternal recumbency and standing were recorded. Data are presented as the median and range. Data obtained 5 minutes post-induction
Proceedings of the Association of Veterinary Anaesthetists Meeting, Madrid, 1999
and changes in the variables over time were compared with Kruskal–Wallis tests. Surgical anaesthesia was achieved in all horses for the required times (85 [range 35–275] minutes). The initial infusion was set at 0.5 mL kg−1 h−1 and then diminished according to the patient’s requirements. There were no significant changes in the monitored variables over time. The median infusion rate was 32.1 [range 20–50] mg kg−1 min−1 ketamine and 0.8 [range 0.5–1.2] mg kg−1 min−1 guaiphenesin. Systolic, diastolic and mean arterial blood pressures were, respectively, 111 [range 80–174], 67 [range 40–139] and 78 [range 54–151] mm Hg. End expired CO2 was 55 [range 30–66] mm Hg, PaCO2, PaO2 and pH were, respectively: 58 [range 36–75] mm Hg, 254 [range 87–415] mm Hg and 7.28 [range 7.21–7.46]. The recovery times were: swallowing 4.5 [range 1–45] minutes, sternal 15.5 [range 10–60] minutes, standing 27 [range 12–105] minutes. The quality of recovery was judged to be poor in two, good in 13 and excellent in nine horses. No recoveries were judged very poor or bad. The infusion of ketamine-guaiphenesin in horses receiving a subanaesthetic dose of halothane appeared to be a safe method to obtain surgical anaesthesia.
most reliable guides to changing anaesthetic dose were changes in magnitude of PaCO2, eyelid aperture, pupil diameter and mean arterial pressure. As the dose of SEVO increased from MAC to 1.75 MAC, PaCO2 increased from 59 2 9 to 92 2 9 mm Hg; eyelid aperture increased from 3.11 2 0.77 to 4.16 2 0.47 mm and pupil diameter from 1.63 2 0.68 to 3.95 2 1.01 mm. Mean arterial pressure decreased from 103 2 5 to 68 2 5 mm Hg. All changes were significant, p ³ 0.05. Both respiratory frequency and heart rate only tended to decrease (p × 0.05) with increasing SEVO concentration (changes were less dose-predictable). Increasing PaCO2, eyelid aperture and pupil diameter, and decreasing mean arterial pressure are consistent clinical indicators of increasing SEVO dose in surgically unstimulated rats.
Influence of sevoflurane and desflurane anaesthesia on blood biochemical values in horses EP Steffey, F Galey, KR Mama and B Puschner University of California, Davis, CA and Colorado State University, Fort Collins, CO, USA
Clinical signs which indicate varying anaesthetic dose, have been reported for spontaneously breathing rats anaesthetized with halothane and isoflurane. This report provides similarly derived data for sevoflurane (SEVO). Eight healthy, male Sprague-Dawley rats, weighing 473 2 24 [mean 2 SD] gm were studied. Individuals, fasted of food but not water, were placed in a chamber filled with SEVO and O2. Following anaesthetic induction and orotracheal intubation (14 gauge IV catheter), SEVO was delivered via a Bain nonrebreathing circuit. The SEVO MAC was determined for each rat using the standard tail-clamp technique. End-tidal gas was collected manually from a special breathing circuit-endotracheal tube adapter and measured via a calibrated infra-red analyser. Four MAC multiples (1.0, 1.25, 1.5, 1.75) were calculated from the individually determined MAC. The order of anaesthetic dose exposure was randomly determined. Each animal was then further instrumented and measurements were made at each of the four MAC multiples after at least 15 minutes of dose stabilization. Data were evaluated by repeated measures ANOVA and Tukey’s tests. The SEVO MAC for these rats was 2.99 2 0.07%. The
The potential toxicity to horses of sevoflurane (SEVO) or desflurane (DES) anaesthesia was evaluated in two groups of five horses anaesthetized under laboratory conditions with only the drug of interest. Anaesthetic conditions for each horse included both spontaneous and controlled ventilation and end-tidal anaesthetic concentrations of 1.0–1.75 MAC. Venous blood was taken within 1 hour of the anaesthetic induction, at 2 hours of anaesthesia, at the end of anaesthesia, and at 1 hour, 1 and 2 days post-anaesthesia for fluoride (F) analysis (ion-specific electrode). Similarly, blood was obtained before and at 1 hour, 1, 2, and 4 days post-anaesthesia for analysis of serum creatinine (CREAT), urea nitrogen (BUN), aspartate aminotransferase (AST) and sorbitol dehydrogenase (SDH) (analyses by our Veterinary Medical Teaching Hospital). Data were grouped (mean 2 SD) and statistically evaluated with repeated measures ANOVA and Bonferroni tests. A value of p ³ 0.05 was considered to be statistically significant. During 5.2 2 0.2 and 5.3 2 0.2 hours of SEVO and DES anaesthesia, respectively, horses were exposed to 7.0 2 0.3 MAC hours of SEVO and 7.3 2 0.3 MAC hours of DES. Results from pre-anaesthetic blood samples were normal. The serum F concentration significantly increased during SEVO but not during DES anaesthesia. Peak F concentration occurred at the end of anaesthesia and reached 50.8 2 7.1 mM L−1, a commonly reported threshold value for kidney damage in rats. Similarly, CREAT reached its greatest value at 1 hour post-SEVO (2.0 2 0.8 mg dL−1; p ³ 0.05), but this is similar to results with other inhalation anaesthetics, including DES. The BUN did not change with either agent. Sorbitol dehydrogenase increased from control values of 4.2 2 0.7 and 4.4 2 0.4 to 10.2 2 1.8 and 16.0 2 2.8 IU L−1 at 1 hour post-anaesthesia for SEVO and
Veterinary Anaesthesia and Analgesia, 2000, 27, 54–62
55
References Steffey EP, Howland D Jr (1978) Cardiovascular effects of halothane in the horse. Am J Vet Res 39, 611–615.
Clinical signs of sevoflurane anaesthesia in spontaneously breathing rats MA Steffey, R Brosnan and EP Steffey Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
Copyright of Veterinary Anaesthesia & Analgesia is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.