The purpose of this study was to evaluate effects of controlled ventilation and positioning on cardiopulmonary function in horses anesthetized with total intravenous anesthesia using a drug combination of medetomidine...The purpose of this study was to evaluate effects of controlled ventilation and positioning on cardiopulmonary function in horses anesthetized with total intravenous anesthesia using a drug combination of medetomidine,lidocaine,butorphanol and propofol (MLBP-TIVA).Five healthy adult horses were anesthetized with MLBP-TIVA for 2-hours on 3-occasions at 4-week interval. In each occasion,horses were anesthetized in lateral recumbency with (CV-LR-group) or without controlled ventilation (SB-LRgroup) or in dorsal recumbency with controlled ventilation (CV-DR-group). Anesthesia was induced with lidocaine (1mg/kg: IV) and propofol (3 mg/kg: IV) following premedications with medetomidine (0. 005 mg/kg: IV) and butorphanol (0. 02 mg/kg: IV),and then maintained by constant rate infusions of propofol (6 mg/kg/hr),medetomidine (0. 0035 mg/kg/h),lidocaine (3 mg/kg/h) and butorphanol (0. 024 mg/kg/h). All horses breathed 100% oxygen during anesthesia. In the CV-groups,horses were mechanically ventilated to maintain arterial CO2pressure (PaCO2)within 40 ~ 50 mmHg. Cardiopulmonary parameters were compared between groups using repeated-measures ANOVA.The level of significance was set at P 【 0. 05.In the SB-LR group,cardiovascular parameters were maintained within acceptable ranges (heart rate: 37 ~ 39beats/min,mean arterial blood pressure: 109 ~ 115 mmHg,mean pulmonary arterial pressure [MPAP]: 28 ~ 29 mmHg,mean right atrial pressure [MRAP]: 19 ~ 21 mmHg,cardiac output: 27 ~ 30 L/min) but severe hypercapnia with insufficient oxygenation (PaCO283 ~ 103 mmHg,arterial O2pressure [PaO2]155 ~171 mmHg) was observed. Cardiopulmonary parameters were maintained with acceptable ranges in the both CV groups. In the CV-LR group,significant decreases in heart rate (29 ~ 31 beats/min,P = 0. 020),cardiac output (17 ~ 21 L/min,P = 0. 005) and PaCO2 (42 ~50 mmHg,P =0. 001) and a significant increase in PaO2 (395 ~419 mmHg,P =0. 005) were observed compared to the SB-group. In the CV-DR group,MPAP (18 ~ 20 mmHg,P = 0. 001),MRAP (15 ~ 17 mmHg,P =展开更多
文摘The purpose of this study was to evaluate effects of controlled ventilation and positioning on cardiopulmonary function in horses anesthetized with total intravenous anesthesia using a drug combination of medetomidine,lidocaine,butorphanol and propofol (MLBP-TIVA).Five healthy adult horses were anesthetized with MLBP-TIVA for 2-hours on 3-occasions at 4-week interval. In each occasion,horses were anesthetized in lateral recumbency with (CV-LR-group) or without controlled ventilation (SB-LRgroup) or in dorsal recumbency with controlled ventilation (CV-DR-group). Anesthesia was induced with lidocaine (1mg/kg: IV) and propofol (3 mg/kg: IV) following premedications with medetomidine (0. 005 mg/kg: IV) and butorphanol (0. 02 mg/kg: IV),and then maintained by constant rate infusions of propofol (6 mg/kg/hr),medetomidine (0. 0035 mg/kg/h),lidocaine (3 mg/kg/h) and butorphanol (0. 024 mg/kg/h). All horses breathed 100% oxygen during anesthesia. In the CV-groups,horses were mechanically ventilated to maintain arterial CO2pressure (PaCO2)within 40 ~ 50 mmHg. Cardiopulmonary parameters were compared between groups using repeated-measures ANOVA.The level of significance was set at P 【 0. 05.In the SB-LR group,cardiovascular parameters were maintained within acceptable ranges (heart rate: 37 ~ 39beats/min,mean arterial blood pressure: 109 ~ 115 mmHg,mean pulmonary arterial pressure [MPAP]: 28 ~ 29 mmHg,mean right atrial pressure [MRAP]: 19 ~ 21 mmHg,cardiac output: 27 ~ 30 L/min) but severe hypercapnia with insufficient oxygenation (PaCO283 ~ 103 mmHg,arterial O2pressure [PaO2]155 ~171 mmHg) was observed. Cardiopulmonary parameters were maintained with acceptable ranges in the both CV groups. In the CV-LR group,significant decreases in heart rate (29 ~ 31 beats/min,P = 0. 020),cardiac output (17 ~ 21 L/min,P = 0. 005) and PaCO2 (42 ~50 mmHg,P =0. 001) and a significant increase in PaO2 (395 ~419 mmHg,P =0. 005) were observed compared to the SB-group. In the CV-DR group,MPAP (18 ~ 20 mmHg,P = 0. 001),MRAP (15 ~ 17 mmHg,P =
