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1.
OBJECTIVE: To characterize variables used to monitor rabbits during inhalation anesthesia. ANIMALS: 8 male New Zealand White rabbits. PROCEDURE: Rabbits were similarly anesthetized with halothane (HAL) or isoflurane (ISO) in a crossover study; half received HAL followed by ISO, and the protocol was reversed for the remaining rabbits. After induction, minimum alveolar concentration (MAC) was determined for each agent, using the tail-clamp method, and variables were recorded at 0.8, 1.0, 1.5, and 2.0 MAC (order randomized). RESULTS: Mean +/- SEM MAC was 1.42 +/- 0.05 and 2.07 +/- 0.09% for HAL and ISO, respectively. Directly measured auricular mean arterial blood pressure was 52.8 +/- 5.6 and 54.8 +/- 6.1 mm Hg at 0.8 MAC for HAL and ISO, respectively, and decreased from these values in a parallel dose-dependent manner. Respiratory frequency remained constant (range, 69 to 78 breaths/min) over the range of HAL doses but incrementally decreased from a mean of 53 (at 0.8 MAC) to 32 breaths/min (at 2.0 MAC) for ISO. The PaCO2 was similar at 0.8 MAC for HAL and ISO and progressively increased with increasing doses of both agents; PaCO2 at 2.0 MAC for ISO was significantly greater than that at 2.0 MAC for HAL (79.8 +/- 13.7 vs 54.9 +/- 4.0 mm Hg, respectively). Eyelid aperture consistently increased in a dose-dependent manner for both anesthetics. CONCLUSIONS: Arterial blood pressure, PaCO2, and eyelid aperture consistently and predictably changed in rabbits in response to changes in anesthetic doses. The magnitude of respiratory depression was greater for ISO than for HAL.  相似文献   

2.
To evaluate the cardiorespiratory changes induced by isoflurane (ISO) anesthesia in the crested caracara (Caracara plancus), eight crested caracaras that weighed 1.0 kg (range 0.9-1.1 kg) were the subjects for the study. The birds were anesthetized by face mask with ISO for brachial artery catheterization. After recovery, anesthesia was re-induced and maintained with ISO with spontaneous ventilation. Electrocardiography, direct systolic arterial blood pressure (SAP), diastolic arterial blood pressure (DAP), mean arterial blood pressure (MAP), respiratory rate (RR), end-tidal carbon dioxide (P(ET)CO2), and cloacal temperature (T degrees C) were measured before induction (baseline, under physical restraint) and after 5, 10, 15, 20, 25, 30, 35, and 40 min of ISO anesthesia. Arterial blood samples were collected for blood gas analysis at baseline, 10, 25, and 40 min. No cardiac arrhythmias were observed in the present study. RR, SAP, DAP, MAP, T degrees C and pH decreased from baseline values, whereas arterial partial pressures of oxygen and carbon dioxide, bicarbonate concentration, and P(ET)CO2 were significantly higher than baseline. Apnea was not observed in any bird. ISO anesthesia is suitable for use in healthy members of this species despite the moderate cardiovascular and respiratory depression produced.  相似文献   

3.
The cardiopulmonary effects of desflurane and sevoflurane anesthesia were compared in cats breathing spontaneously. Heart (HR) and respiratory (RR) rates; systolic (SAP), diastolic (DAP) and mean arterial (MAP) pressures; partial pressure of end tidal carbon dioxide (PETCO2), arterial blood pH (pH), arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2); base deficit (BD), arterial oxygen saturation (SaO2) and bicarbonate ion concentration (HCO3) were measured. Anesthesia was induced with propofol (8+/-2.3mg/kg IV) and maintained with desflurane (GD) or sevoflurane (GS), both at 1.3 MAC. Data were analyzed by analysis of variance (ANOVA), followed by the Tukey test (P<0.05). Both anesthetics showed similar effects. HR and RR decreased when compared to the basal values, but remained constant during inhalant anesthesia and PETCO2 increased with time. Both anesthetics caused acidemia and hypercapnia, but BD stayed within normal limits. Therefore, despite reducing HR and SAP (GD) when compared to the basal values, desflurane and sevoflurane provide good stability of the cardiovascular parameters during a short period of inhalant anesthesia (T20-T60). However, both volatile anesthetics cause acute respiratory acidosis in cats breathing spontaneously.  相似文献   

4.
OBJECTIVE: To characterize isoflurane (ISO)-induced anesthesia in ferrets and rats. ANIMALS: 8 ferrets (Mustela putorius furo) and 8 Sprague-Dawley rats. PROCEDURE: Ferrets and rats were anesthetized in a similar manner, using ISO in oxygen. Minimum alveolar concentration (MAC) was determined, using the tail-clamp method. Immediately thereafter, assessments were recorded for 0.8, 1.0, 1.5, and 2.0 MAC (order randomized) of ISO. RESULTS: MAC of ISO was (mean +/- SEM) 1.74 +/- 0.03 and 1.58 +/- 0.05% for ferrets and rats, respectively. Mean arterial blood pressure (MAP) was 75.0 +/- 4.3 and 107.9 +/- 2.7 mm Hg at 0.8 MAC for ferrets and rats, respectively, and decreased in a parallel dose-dependent manner. Respiratory frequency decreased in rats as ISO dose increased; however, respiratory frequency increased in ferrets as ISO dose increased from 0.8 to 1.5 MAC but then decreased at 2.0 MAC. At 0.8 MAC, hypoventilation was much greater in ferrets (PaCO2 = 71.4 +/- 3.5 mm Hg), compared with rats (PaCO2 = 57.7 +/- 1.9 mm Hg). In both species, PaCO2 progressively increased as anesthetic dose increased. Eyelid aperture of ferrets increased in a dose-dependent manner. Pupil diameter in ferrets and rats increased as ISO dose increased. CONCLUSIONS AND CLINICAL RELEVANCE: The MAP and PaCO2 in ferrets and rats and eyelid aperture in ferrets consistently and predictably changed in response to changes in anesthetic dose of ISO. Magnitude of respiratory depression was greater in ferrets than rats. Changes in MAP and PaCO2 in ferrets and rats and eyelid aperture in ferrets are consistent guides to changes in depth of ISO-induced anesthesia.  相似文献   

5.
OBJECTIVE: To compare the cardiorespiratory changes induced by equipotent concentrations of halothane (HAL), isoflurane (ISO) and sevoflurane (SEVO) before and after hemorrhage. STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: Twenty-four healthy adult dogs weighing 15.4 +/- 3.4 kg (mean +/- SD). METHODS: Animals were randomly allocated to one of three groups (n = 8 per group). In each group, anesthesia was maintained with 1.5 minimum alveolar concentration of HAL (1.3%), ISO (1.9%) and SEVO (3.5%) in oxygen. Controlled ventilation was performed to maintain eucapnia. Cardiorespiratory variables were evaluated at baseline (between 60 and 90 minutes after induction), immediately after and 30 minutes after the withdrawal of 32 mL kg(-1) of blood (40% of the estimated blood volume) over a 30-minute period. RESULTS: During baseline conditions, ISO and SEVO resulted in higher cardiac index (CI) than HAL. Heart rates were higher with SEVO at baseline, while mean arterial pressure (MAP) and mean pulmonary arterial pressure did not differ between groups. Although heart rate values were higher for ISO and SEVO after hemorrhage, only ISO resulted in a higher CI when compared with HAL. In ISO-anesthetized dogs, MAP was higher immediately after hemorrhage, and this was related to better maintenance of CI and to an increase in systemic vascular resistance index from baseline. CONCLUSIONS: Although the hemodynamic responses of ISO and SEVO are similar in normovolaemic dogs, ISO results in better maintenance of circulatory function during the early period following a massive blood loss. CLINICAL RELEVANCE: Inhaled anesthetics should be used judiciously in animals presented with blood loss. However, if an inhalational agent is to be used under these circumstances, ISO may provide better hemodynamic stability than SEVO or HAL.  相似文献   

6.
OBJECTIVE: To examine the effect of 64% nitrous oxide (N2O) on halothane (HAL), isoflurane (ISO) or sevoflurane (SEV) requirements in dogs undergoing ovariohysterectomy. STUDY DESIGN: Prospective, randomized, clinical trial. ANIMALS: Ninety, healthy dogs of (mean +/- SD) body weight 21.2 +/- 10.0 kg and age 17.8 +/- 22.8 months. MATERIALS AND METHODS: After premedication with acepromazine, hydromorphone and glycopyrrolate, anesthesia was induced with thiopental administered to effect. Dogs received one of six inhalant protocols (n = 15 group): HAL; HAL/N2O; ISO; ISO/N2O; SEV; or SEV/N2O. End-tidal CO2 was maintained at 40 +/- 2 mmHg with intermittent positive pressure ventilation (IPPV). Body temperature, heart rate, indirect systemic arterial blood pressures, inspired and end-tidal CO2, volatile agent, N2O and O2 were recorded every 5 minutes. The vaporizer setting was decreased in 0.25-0.5% decrements to elicit a palpebral reflex, and this level maintained. Statistical analysis included two-way anova for repeated measures with Bonferroni's correction factor and statistical significance assumed when p < 0.05. Percentage reduction in end-tidal volatile agent was calculated at 60 minutes after starting study. RESULTS: End-tidal HAL, ISO and SEV decreased when N2O was administered. Percentage reduction: HAL (12.4%); ISO (37.1%) and SEV (21.4%). Diastolic, mean and systolic blood pressures increased in ISO/N2O compared with ISO. Heart rate increased in ISO/N2O and SEV/N2O compared with ISO and SEV, respectively. Systolic, mean and diastolic blood pressures increased in SEV compared with HAL and ISO. Systolic, mean, diastolic blood pressures and heart rate increased in SEV/N2O and ISO/N2O compared with HAL/N2O. CONCLUSIONS: N2O reduces HAL, ISO and SEV requirements in dogs undergoing ovariohysterectomy. Cardiovascular stimulation occurred when N2O was used with ISO, less so with SEV and not with HAL  相似文献   

7.
OBJECTIVE: To evaluate the influence of epidural administration of xylazine hydrochloride on the minimum alveolar concentration of isoflurane (MAC(ISAO)) and cardiopulmonary system in anesthetized dogs. ANIMALS: 6 clinically normal dogs. PROCEDURE: Dogs were anesthetized with isoflurane in oxygen after randomly being assigned to receive 1 of the following 4 treatments: epidural administration of saline (0.9% NaCl) solution or xylazine at a dose of 0.1, 0.2, or 0.4 mg x kg(-1). Experiments were performed on 5 occasions with at least a 1-week interval between experiments; each dog received all 4 treatments. Following instrumentation, the concentration of isoflurane was maintained constant for 15 minutes at the MAC(ISO) that had been determined for each dog, and data on heart rate, arterial blood pressure, respiratory rate, tidal volume, minute volume, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, and arterial pH were collected. The epidural treatment was administered, and 30 minutes later, data were again collected. From this point on, determination of the MAC(ISO) following epidural treatment (ie, MAC(ISO+EPI)) was initiated. Cardiopulmonary data were collected before each electrical supramaximal stimulus during MAC(ISO+EPI) determinations. RESULTS: The mean (+/-SD) MAC(ISO) was 1.29 +/- 0.04%. The epidural administration of xylazine at doses of 0.1, 0.2, and 0.4 mg x kg(-1) decreased the MAC(ISO), respectively, by 8.4 +/- 2.4%, 21.7 +/- 4.9%, and 33.4 +/- 2.64%. Cardiopulmonary effects were limited. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of xylazine decreases the MAC(ISO) in a dose-dependent manner and is associated with few cardiopulmonary effects in anesthetized dogs.  相似文献   

8.
Objective The purpose of this study was to determine the cardiovascular effects of sevoflurane in calves. Study design Prospective experimental study. Animals Six, healthy, 8–12‐week‐old Holstein calves weighing 80 ± 4.5 (mean ± SEM) kg were studied. Methods Anesthesia was induced by face‐mask administration of 7% sevoflurane in O2. Calves tracheae were intubated, placed in right lateral recumbency, and maintained with 3.7% end‐tidal concentration sevoflurane for 30 minutes to allow catheterization of the auricular artery and placement of a Swan‐Ganz thermodilution catheter into the pulmonary artery. After instrumentation, administration of sevoflurane was temporarily discontinued until mean arterial pressure was > 100 mm Hg. Baseline values were recorded and the vaporizer output increased to administer 3.7% end‐tidal sevoflurane concentration. Ventilation was controlled to maintain normocapnia. The following were recorded at 5, 10, 15, 30 and 45 minutes after collection of baseline data and expressed as the mean value (± SEM): direct systolic, diastolic, and mean arterial blood pressures; cardiac output; mean pulmonary arterial pressure; pulmonary arterial occlusion pressure, heart rate; and pulmonary arterial temperature. Cardiac index and systemic and pulmonary vascular resistance values were calculated using standard formulae. Arterial blood gases were analyzed at baseline, and at 15 and 45 minutes. Differences from baseline values were determined using one‐way analysis of variance for repeated measures with post‐hoc differences between mean values identified using Dunnet's test (p < 0.05). Results Mean time from beginning sevoflurane administration to intubation of the trachea was 224 ± 9 seconds. The mean end‐tidal sevoflurane concentration at baseline was 0.7 (± 0.11)%. Sevoflurane anesthesia was associated with decreased arterial blood pressure at all sampling times. Mean arterial blood pressure decreased from a baseline value of 112 ± 7 mm Hg to a minimum value of 88 ± 4 mm Hg at 5 minutes. Compared with baseline, arterial pH was decreased at 15 minutes. Pulmonary arterial blood temperature was decreased at 15, 30 and 45 minutes. Arterial CO2 tension increased from a baseline value of 43 ± 3 to 54 ± 4 mm Hg (5.7 ± 0.4 to 7.2 ± 0.3 kPa) at 15 minutes. Mean pulmonary arterial pressure was increased at 30 and 45 minutes. Pulmonary arterial occlusion pressure increased from a baseline value of 18 ± 2 to 23 ± 2 mm Hg at 45 minutes. There were no significant changes in other measured variables. All calves recovered from anesthesia uneventfully. Conclusion We conclude that sevoflurane for induction and maintenance of anesthesia was effective and reliable in these calves and that neither hypotension nor decreased cardiac output was a clinical concern. Clinical relevance Use of sevoflurane for mask induction and maintenance of anesthesia in young calves is a suitable alternative to injectable and other inhalant anesthetics.  相似文献   

9.
Objectives To determine whether moderate hypothermia during anesthesia significantly affects the serum concentration of transdermally delivered fentanyl and whether halothane or isoflurane affect these concentrations. Study Design Randomized cross‐over experimental trial. Animals Six mature, healthy Beagles (three males, three females) weighing 10.6 ± 0.43 kg. Methods A 50‐µg hour?1 fentanyl patch was applied 36 hours prior to anesthesia. Anesthesia was induced at time 0 (t = 0). Each dog received four treatments: isoflurane + normothermia (ISO‐NORM), isoflurane + hypothermia (ISO‐HYPO), halothane + normothermia (HAL‐NORM), and halothane + hypothermia (HAL‐HYPO). Dogs were intubated and maintained at 1.5 times MAC. Animals in the hypothermia treatments were cooled to 35 °C during anesthesia. Serum fentanyl analysis was performed at ?36, ?24, ?12, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 18, and 26 hours. Direct arterial blood pressures and arterial blood gases were monitored. Results The mean body temperatures (±SEM) during the anesthetic period for the four treatments were: ISO‐NORM = 37.7 ± 0.07 °C, ISO‐HYPO = 35.8 ± 0.1 °C, HAL‐NORM = 37.7 ± 0.06 °C, and HAL‐HYPO = 35.8 ± 0.13 °C. The mean (±SEM) serum fentanyl concentrations (SFC) for both hypothermia treatments were significantly lower than baseline concentrations at t = 1 hour and persisted for the duration of anesthesia for the ISO‐HYPO treatment but only from t = 1 to 2 hours for the HAL‐HYPO treatment. Serum fentanyl concentrations returned to baseline within one hour of the end of anesthesia, regardless of body temperature. There were no significant differences between treatments for systolic or diastolic blood pressure but mean blood pressures were higher during normothermia versus hypothermia during the last hour of anesthesia. Conclusions and clinical relevance Hypothermia during inhalation anesthesia produced a significant reduction in SFC using transdermal administration and was more protracted with isoflurane than halothane anesthesia. While significant reductions in SFC occurred, the SFC were still within the range believed to confer analgesia.  相似文献   

10.
This study examined the effect of temperature on volatile concentrations of 2 inhalant anesthetics, isoflurane (ISO) and sevoflurane (SEVO), delivered via open-drop technique, as well as the characteristics of induction and recovery using the open-drop method in mice. Testing revealed that temperature had no effect on the volatile concentration of either ISO or SEVO. However, it was determined that open-drop delivery of ISO or SEVO is a viable means of anesthetizing mice under certain conditions. The volatile concentration required to induce anesthesia in mice following the application of 0.5 mL of anesthetic in an induction chamber of 725 mL volume at 87.6 kPa and 20°C was measured with a precision gas analyzer. For ISO, anesthesia was induced at concentrations of 6.80 ± 0.57% [mean ± standard deviation (s)] after 35.70 ± 6.95 s (n = 10), while SEVO induction took significantly longer (45.50 ± 9.96 s) and required higher volatile concentrations [7.41 ± 0.57% (n = 10)]. The animals recovered rapidly from both ISO and SEVO-based induction.  相似文献   

11.
The cardiopulmonary effects of a ketamine/ acepromazine combination was studied in ten cats subjected to a 25% whole blood volume loss. Test parameters included cardiac output, measured via thermodilution, heart rate, respiratory rate, arterial blood pressure (systolic, diastolic and mean) and blood gas analysis. Values for cardiac index, stroke volume and systemic vascular resistance were calculated from these data. Posthemorrhage, cardiac output, cardiac index, stroke volume, heart rate and measurements of arterial blood pressure were significantly decreased (p less than 0.05). Following the induction of ketamine/ acepromazine anesthesia, cardiac output, cardiac index, stroke volume and heart rate showed mild but statistically insignificant declines and were above their respective posthemorrhage values 120 min into ketamine/ acepromazine anesthesia. Measurements of arterial blood pressure showed further declines from their respective posthemorrhage values that were statistically significant (p less than 0.05). Following hemorrhage, respiratory rate increased significantly (p less than 0.05), associated with a fall in arterial CO2 tension. During ketamine/ acepromazine anesthesia, respiratory rate showed a dramatic and significant decline (p less than 0.05) with arterial CO2 tension rising to prehemorrhage values. Systemic vascular resistance, arterial O2 tension and pH remained essentially unchanged throughout the experimental period.  相似文献   

12.
The objective of this study was to evaluate the use of desflurane after induction of anesthesia with propofol in dogs sedated with romifidine or medetomidine. Each of 8 healthy dogs received intravenously, in random order, 3 preanesthetic protocols: romifidine, 40 microg/kg of body weight (BW) (R40); romifidine, 80 microg/kg BW (R80); and medetomidine, 10 microg/kg BW (MED). Cardiovascular and respiratory variables were recorded during the procedure. Time to extubation, time to sternal recumbency, and time to standing were also recorded. Heart rate and respiratory rate decreased significantly during sedation from baseline values, but there were no differences between the means for the 3 preanesthetic protocols. Mean values for heart rate, mean arterial blood pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate, tidal volume, arterial oxygen saturation, end-tidal CO2 level, pH, and arterial blood gas values during anesthesia were similar for the 3 protocols. The mean end-tidal desflurane concentration was significantly lower with the R80 protocol than with the R40 protocol. The mean time to extubation was significantly shorter with the R40 protocol than with the R80 and MED protocols.  相似文献   

13.
Objective To characterize the acute cardiopulmonary effects of severe hemorrhage in anesthetized horses. Study design Prospective experimental study. Animals Three geldings and six mares, aged 14.4 ± 2.7 years, weighing 486 ± 41 kg (range: 425–550 kg). Methods Horses were anesthetized using xylazine, guaifenesin, ketamine and halothane or isoflurane. Cardiovascular variables, hematocrit, total solids, capillary refill time (CRT) and color of mucous membranes were measured as blood was collected from the carotid artery into sterile plastic bags. Arterial blood gas analysis was also performed. Results The average amount of blood collected from these horses was (mean ± SD) 53 ± 4.8 mL kg?1 bodyweight (range: 23–32 kg) over 39 ± 4 minutes. Hematocrit decreased from 38 ± 3 to 32 ± 2% after induction of anesthesia and did not change significantly over the period of blood loss. Total solids decreased significantly after induction of anesthesia, and over the period of blood loss. Systolic, mean, diastolic and pulse pressures decreased as blood was lost. Heart rate did not change significantly. Capillary refill time increased from 1.6 ± 0.4 seconds to 4.8 ± 1.3 seconds as blood loss increased. Mucous membrane color deteriorated progressively. Arterial PO2 decreased significantly over the period of blood loss. Conclusions Hematocrit and heart rate do not change significantly during acute severe hemorrhage in the anesthetized horse. Arterial blood pressure, pulse pressure and PaO2 decrease as blood loss increases. Changes in mucous membrane color and CRT also occur as blood loss increases. Clinical relevance During severe hemorrhage in the inhalant‐anesthetized horse, both heart rate and hematocrit remain unchanged. Blood pressure decreases and changes in arterial PO2 correlate most strongly with volume of blood lost.  相似文献   

14.
Cardiopulmonary effects of a tiletamine-zolazepam combination in sheep   总被引：2，自引：0，他引：2  
To assess the effects on heart and lung function, a tiletamine-zolazepam (TZ) anesthetic combination was evaluated in 10 Dorset-type ewes. Ewes were randomly allotted to 2 equal groups. Ewes of groups 1 and 2 were given a single bolus of TZ (12 and 24 mg/kg of body weight, IV, respectively) at time zero. Hemodynamic, pulmonary, and ventilation variables were measured at 15-minute intervals to 120 minutes. Blood gas variables were evaluated at 5-minute intervals for the first 30 minutes, then at 15-minute intervals to 120 minutes. In all sheep, TZ administration induced rapid, smooth induction, with gradual and unremarkable recovery. Anesthesia duration was not significantly different between groups (mean +/- SD, 39 +/- 5 and 40 +/- 14 minutes for groups 1 and 2, respectively). Immediate drug effects included apnea, decreased mean arterial blood pressure, and arterial hypoxemia. Cardiac output was significantly decreased in both groups at all times after drug administration. Significant changes in group-1 ewes included increased pulmonary and systemic vascular resistances and decreased inspired minute ventilation, tidal volume, and respiratory airflow. Significant changes in group-2 ewes included increased systemic vascular resistance and decreased pulmonary arterial pressure, inspired minute ventilation, and respiratory airflow. Both drug dosages induced apneustic breathing patterns and caused significant changes in arterial and venous blood hemoglobin concentrations and PCV. Tiletamine-zolazepam is useful for intermediate-duration anesthesia in sheep.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
The cardiopulmonary effects of a halothane/oxygen combination were studied in eight cats subjected to a 25% whole blood volume loss. Test parameters included cardiac output measured via thermodilution, heart rate, respiratory rate, arterial blood pressure (systolic, diastolic and mean) and blood gas analysis. Values for cardiac index, stroke volume and systemic vascular resistance were calculated from these data. Posthemorrhage cardiac output, cardiac index, stroke volume and measurements of arterial blood pressure were significantly decreased (p less than 0.05). Heart rate remained unchanged. Following induction of halothane anesthesia the above parameters experienced a further significant decline (p less than 0.05) from their immediate preanesthetic (i.e. posthemorrhage) values. Heart rate also significantly decreased (p less than 0.05). Thirty minutes following the cessation of halothane anesthesia these values returned to near-hemorrhage levels, being above their respective preanesthetic values. Systemic vascular resistance initially rose, peaking ten minutes into halothane anesthesia, before gradually falling to prehemorrhage values at the end of halothane anesthesia. Following hemorrhage, respiratory rate demonstrated a transient increase, associated with an arterial CO2 tension fall, before returning to initial values at the preanesthetic time. During halothane anesthesia respiratory rate remained unchanged whereas arterial CO2 tension rose significantly (p less than 0.05) and pH declined slightly from preanesthetic readings. These returned to prehemorrhage values 30 minutes following the cessation of halothane anesthesia.  相似文献   

16.
Loss of rear motor control is the main limiting factor in the use of caudal epidural anesthesia in the horse. In man and laboratory animals, a small dose of an opiate combined with a local anesthetic enhances analgesia without impairing motor function. Thus, the amount of local anesthetic administered may be reduced. Butorphanol is an opiate widely used in horses. It has a good margin of safety and few cardiorespiratory effects. The effects of lidocaine (0.25 mg/kg) and lidocaine-butorphanol (0.25 mg/kg, and 0.04 mg/kg, respectively) were compared in 2 groups of 5 healthy unsedated mares. Horses in each group received either lidocaine or lidocaine-butorphanol in saline solution for a total volume of 0.0165 mg/kg. Epidural injection was performed at the first coccygeal interspace. Each mare was used only once. Cutaneous analgesia was assessed by a response to a pin prick; and visceral analgesia was assessed by response to a noxious stimulus applied to the urethra. Heart rate, respiratory rate, and arterial blood pressure were also measured. Analysis of the results showed an increase in duration of both cutaneous and visceral analgesia in the mares given lidocaine-butorphanol. Cutaneous analgesia increased from 36 +/- 13 to 150 +/- 21 min and visceral analgesia increased from 22 +/- 10 to 162 +/- 16 min. A cranial extension of the cutaneous analgesia was also observed. Cardiorespiratory depression or signs of excitation were not observed. However, these mares demonstrated peculiar walking in the hind limbs, not associated with signs of ataxia or hyperkinesia.  相似文献   

17.
OBJECTIVE: To characterize the effect of general anesthesia and minor surgery on renal function in horses. ANIMALS: 9 mares with a mean (+/- SE) age and body weight of 9+/-2 years and 492+/-17 kg, respectively. PROCEDURE: The day before anesthesia, urine was collected (catheterization) for 3 hours to quantitate baseline values, and serum biochemical analysis was performed. The following day, xylazine (1.1 mg/kg, IV) was administered, and general anesthesia was induced 5 minutes later with diazepam (0.04 mg/kg, IV) and ketamine (2.2 mg/kg, IV). During 2 hours of anesthesia with isoflurane, Paco2 was maintained between 48 and 52 mm Hg, and mean arterial blood pressure was between 70 and 80 mm Hg. Blood and urine were collected at 30, 60, and 120 minutes during and at 1 hour after anesthesia. RESULTS: Baseline urine flow was 0.92+/-0.17 ml/kg/h and significantly increased at 30 and 60 minutes after xylazine administration (2.14+/-0.59 and 2.86+/-0.97 ml/kg/h respectively) but returned to baseline values by the end of anesthesia. Serum glucose concentration increased from 12+/-4 to 167+/-8 mg/dl at 30 minutes. Glucosuria was not observed. CONCLUSIONS AND CLINICAL RELEVANCE: Transient hyperglycemia and an increase in rine production accompanies a commonly used anesthetic technique for horses. The increase in urine flow is not trivial and should be considered in anesthetic management decisions. With the exception of serum glucose concentration and urine production, the effect of general anesthesia on indices of renal function in clinically normal horses is likely of little consequence in most horses admitted for elective surgical procedures.  相似文献   

18.
OBJECTIVE: To determine the minimum alveolar concentration (MAC) of isoflurane (ISO) in llamas. STUDY DESIGN: Prospective study. ANIMALS: Eight adult neutered male llamas (9 +/- 1 years [x +/- SD], 177 +/- 29 kg). METHODS: Anesthesia was induced and maintained in otherwise unmedicated llamas with a mixture of ISO in oxygen administered through a standard small-animal, semi-closed circle system using an out-of-circle, agent-specific vaporizer. The time from mask placement to intubation was recorded. Inspired and end-tidal (ET) ISO was sampled continuously. At each anesthetic concentration, a constant ET ISO was maintained for at least 20 minutes before application of a noxious electrical stimulus (50 volts, 5 Hz, 10 ms for up to 1 minute). A positive or negative response to the stimulus was recorded, and ET ISO then increased (if positive response) or decreased (if negative response) by 10% to 20%. Individual MAC was the average of multiple determinations. Body temperature was maintained at 37 +/- 1 degrees C. Selected cardiopulmonary variables (heart rate [HR], respiratory rate [RR], arterial blood pressure [ABP]) and ET ISO were recorded at hourly intervals from first ISO. Arterial blood was collected for pH, PCO2, PO2 analysis and measurement of packed cell volume (PCV) and total protein (TP) at 2 hour intervals. Following MAC determination, the anesthetic was discontinued and llamas were allowed to recover. Duration and quality of recovery were noted. RESULTS: The time from start of induction by mask to completion of intubation took 19.1 +/- 4.8 minutes. The MAC of ISO corrected to one atmosphere at sea level (barometric pressure 760 mm Hg) in these llamas was 1.05 +/- 0.17%. Mean ABP increased from 70 +/- 26 mm Hg at the end of the first hour of anesthesia to 102 +/- 7 mm Hg measured at the end of the sixth hour of anesthesia. ET ISO decreased from 2.06 +/- 0.10% to 1.27 +/- 0.07% over the same time period, but MAC did not change with time. The duration from first ISO to discontinuation of ISO averaged 6.19 +/- 0.9 hours. Animals were able to support their heads in a sternal posture at 23 +/- 10 minutes, and stood 62 +/- 26 minutes following discontinuation of the anesthetic. CONCLUSION: The MAC for ISO is similar to, but slightly lower than, values reported for other species. CLINICAL RELEVANCE: Knowledge of MAC may facilitate appropriate clinical use and provide the basis for future investigation of ISO in llamas.  相似文献   

19.
The Hemodynamic Response of Calves to Tiletamine-Zolazepam Anesthesia   总被引：1，自引：0，他引：1  
Six isoflurane-anesthetized calves were instrumented for hemodynamic studies and allowed to recover from anesthesia. When the mean arterial blood pressure rose to 100 mmHg or when vigorous movement occurred, a 1:1 tiletamine-zolazepam mixture (4 mg/kg) was administered intravenously (IV). Values for cardiac output, cardiac index, stroke index, central venous pressure, and right ventricular stroke work index did not change significantly. Systolic, mean, and diastolic arterial blood pressures and systemic vascular resistance were significantly decreased below baseline at 5 minutes; they were significantly increased above baseline at 20 minutes and remained so throughout the 60 minute study. Changes in left ventricular stroke work index and rate pressure product were similar to those of arterial blood pressure and systemic vascular resistance, although they were not significant. Heart rate and pulmonary capillary wedge pressure decreased significantly but gradually returned to baseline at 40 minutes and then increased significantly above baseline by the end of the study. Minor venous-arterial shunting or perhaps mismatching of ventilation and perfusion appeared to have developed in the later stages of the study. This was reflected in a minor increase in the arterial partial pressure of carbon dioxide (PaCO2) and a decrease in the arterial partial pressure of oxygen (PaO2) and arterial pH. At the dose administered, the hemodynamic changes induced by tiletamine-zolazepam were minimal and were compatible with safe anesthesia in calves.  相似文献   

20.
The objective of the study was to describe the effects of carbon dioxide pneumoperitoneum and Trendelenburg position on arterial blood gas values in horses anesthetized for laparoscopy. The study design was a prospective case series using 14 healthy adult horses anesthetized for elective laparoscopic surgery. All horses in the study were maintained under anesthesia with halothane in oxygen with intermittent positive-pressure ventilation. A pneumoperitoneum of 15 mmHg or less was achieved with carbon dioxide, and horses were tilted to a 35-degree Trendelenburg position to allow the completion of laparoscopic cryptorchidectomy (n = 13) or ovariectomy (n = 1). Heart rate, mean arterial pressure, and arterial blood gases were recorded at six time intervals throughout the procedure. Results of the study indicated a pH that decreased and partial pressure of carbon dioxide (PaCO2) and mean arterial pressure that increased over time and differed significantly from baseline during Trendelenburg position. Partial pressure of oxygen (PaO2) was significantly lower than baseline after assumption of Trendelenburg position and did not improve on return to normal recumbency and abdominal pressure. As body weight increased, pH and PaO2 decreased and PaCO2 increased. We concluded that horses placed in Trendelenburg position have changes that are transient, with the exception of PaO2. Heavier horses have a greater change in pH, PaCO2, and PaO2 than lighter horses during abdominal insufflation and Trendelenburg position. The changes incurred during CO2 abdominal insufflation and Trendelenburg position are transient, with the exception of a decreased PaO2. Heavy horses undergoing abdominal insufflation and Trendelenburg position should be closely monitored for critical cardiopulmonary values.  相似文献   

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