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1.
ObjectiveTo test if the addition of butorphanol by constant rate infusion (CRI) to medetomidine–isoflurane anaesthesia reduced isoflurane requirements, and influenced cardiopulmonary function and/or recovery characteristics.Study designProspective blinded randomised clinical trial.Animals61 horses undergoing elective surgery.MethodsHorses were sedated with intravenous (IV) medetomidine (7 μg kg?1); anaesthesia was induced with IV ketamine (2.2 mg kg?1) and diazepam (0.02 mg kg?1) and maintained with isoflurane and a CRI of medetomidine (3.5 μg kg?1 hour?1). Group MB (n = 31) received butorphanol CRI (25 μg kg?1 IV bolus then 25 μg kg?1 hour?1); Group M (n = 30) an equal volume of saline. Artificial ventilation maintained end-tidal CO2 in the normal range. Horses received lactated Ringer’s solution 5 mL kg?1 hour?1, dobutamine <1.25 μg kg?1 minute?1 and colloids if required. Inspired and exhaled gases, heart rate and mean arterial blood pressure (MAP) were monitored continuously; pH and arterial blood gases were measured every 30 minutes. Recovery was timed and scored. Data were analyzed using two way repeated measures anova, independent t-tests or Mann–Whitney Rank Sum test (p < 0.05).ResultsThere was no difference between groups with respect to anaesthesia duration, end-tidal isoflurane (MB: mean 1.06 ± SD 0.11, M: 1.05 ± 0.1%), MAP (MB: 88 ± 9, M: 87 ± 7 mmHg), heart rate (MB: 33 ± 6, M: 35 ± 8 beats minute?1), pH, PaO2 (MB: 19.2 ± 6.6, M: 18.2 ± 6.6 kPa) or PaCO2. Recovery times and quality did not differ between groups, but the time to extubation was significantly longer in group MB (26.9 ± 10.9 minutes) than in group M (20.4 ± 9.4 minutes).Conclusion and clinical relevanceButorphanol CRI at the dose used does not decrease isoflurane requirements in horses anaesthetised with medetomidine–isoflurane and has no influence on cardiopulmonary function or recovery.  相似文献   

2.
ObjectiveTo examine the cardiopulmonary effects of infusions of remifentanil or morphine, and their influence on recovery of horses anesthetized with isoflurane and dexmedetomidine.Study designRandomized crossover study with 7-day rest periods.AnimalsSix adult horses (507 ± 61 kg).MethodsAfter the horses were sedated with xylazine, anaesthesia was induced with ketamine and diazepam, and maintained with isoflurane. After approximately 60 minutes, a dexmedetomidine infusion was started (0.25 μg kg?1 then 1.0 μg?1 kg?1 hour?1) in combination with either saline (group S), morphine (0.15 mg kg?1 then 0.1 mg kg?1 hour?1; group M), or remifentanil (6.0 μg kg?1 hour?1; group R) for 60 minutes. Mean arterial pressure, heart rate, end-tidal carbon dioxide tension, and end-tidal isoflurane concentration were recorded every 5 minutes. Core body temperature, cardiac output, right ventricular and arterial blood-gas values were measured every 15 minutes. Cardiac index, systemic vascular resistance (SVR), intrapulmonary shunt fraction, alveolar dead space, oxygen delivery and extraction ratio were calculated. Recoveries were videotaped and scored by two observers blinded to the treatment. Data were analyzed using repeated measures anova followed by Dunnett’s or Bonferroni’s significant difference test. Recovery scores were analyzed using a Kruskal–Wallis test.ResultsNo significant differences were found among groups. Compared to baseline, heart rate decreased and SVR increased significantly in all groups, and cardiac index significantly decreased in groups S and M. Hemoglobin concentration, oxygen content and oxygen delivery significantly decreased in all groups. The oxygen extraction ratio significantly increased in groups M and R. Lactate concentration significantly increased in group S. Recovery scores were similar among groups.Conclusions and clinical relevanceDexmedetomidine alone or in combination with remifentanil or morphine infusions was infused for 60 minutes without adverse effects in the 6 healthy isoflurane-anesthetized horses in this study.  相似文献   

3.
ObjectiveTo evaluate medetomidine as a continuous rate infusion (CRI) in horses in which anaesthesia is maintained with isoflurane and CRIs of ketamine and lidocaine.Study designProspective, randomized, blinded clinical trial.AnimalsForty horses undergoing elective surgery.MethodsAfter sedation and induction, anaesthesia was maintained with isoflurane. Mechanical ventilation was employed. All horses received lidocaine (1.5 mg kg?1 initially, then 2 mg kg?1 hour?1) and ketamine (2 mg kg?1 hour?1), both CRIs reducing to 1.5 mg kg?1 hour?1 after 50 minutes. Horses in group MILK received a medetomidine CRI of 3.6 μg kg?1 hour?1, reducing after 50 minutes to 2.75 μg kg?1 hour?1, and horses in group ILK an equal volume of saline. Mean arterial pressure (MAP) was maintained above 70 mmHg using dobutamine. End-tidal concentration of isoflurane (FE′ISO) was adjusted as necessary to maintain surgical anaesthesia. Group ILK received medetomidine (3 μg kg?1) at the end of the procedure. Recovery was evaluated. Differences between groups were analysed using Mann-Whitney, Chi-Square and anova tests as relevant. Significance was taken as p < 0.05.ResultsFE′ISO required to maintain surgical anaesthesia in group MILK decreased with time, becoming significantly less than that in group ILK by 45 minutes. After 60 minutes, median (IQR) FE′ISO in MILK was 0.65 (0.4–1.0) %, and in ILK was 1 (0.62–1.2) %. Physiological parameters did not differ between groups, but group MILK required less dobutamine to support MAP. Total recovery times were similar and recovery quality good in both groups.Conclusion and clinical relevanceA CRI of medetomidine given to horses which were also receiving CRIs of lidocaine and ketamine reduced the concentration of isoflurane necessary to maintain satisfactory anaesthesia for surgery, and reduced the dobutamine required to maintain MAP. No further sedation was required to provide a calm recovery.  相似文献   

4.
ObjectiveTo evaluate the cardiovascular, respiratory, electrolyte and acid–base effects of a continuous infusion of dexmedetomidine during propofol–isoflurane anesthesia following premedication with dexmedetomidine.Study designProspective experimental study.AnimalsFive adult male Walker Hound dogs 1–2 years of age averaging 25.4 ± 3.6 kg.MethodsDogs were sedated with dexmedetomidine 10 μg kg?1 IM, 78 ± 2.3 minutes (mean ± SD) before general anesthesia. Anesthesia was induced with propofol (2.5 ± 0.5 mg kg?1) IV and maintained with 1.5% isoflurane. Thirty minutes later dexmedetomidine 0.5 μg kg?1 IV was administered over 5 minutes followed by an infusion of 0.5 μg kg?1 hour?1. Cardiac output (CO), heart rate (HR), ECG, direct blood pressure, body temperature, respiratory parameters, acid–base and arterial blood gases and electrolytes were measured 30 and 60 minutes after the infusion started. Data were analyzed via multiple linear regression modeling of individual variables over time, compared to anesthetized baseline values. Data are presented as mean ± SD.ResultsNo statistical difference from baseline for any parameter was measured at any time point. Baseline CO, HR and mean arterial blood pressure (MAP) before infusion were 3.11 ± 0.9 L minute?1, 78 ± 18 beats minute?1 and 96 ± 10 mmHg, respectively. During infusion CO, HR and MAP were 3.20 ± 0.83 L minute?1, 78 ± 14 beats minute?1 and 89 ± 16 mmHg, respectively. No differences were found in respiratory rates, PaO2, PaCO2, pH, base excess, bicarbonate, sodium, potassium, chloride, calcium or lactate measurements before or during infusion.Conclusions and clinical relevanceDexmedetomidine infusion using a loading dose of 0.5 μg kg?1 IV followed by a constant rate infusion of 0.5 μg kg?1 hour?1 does not cause any significant changes beyond those associated with an IM premedication dose of 10 μg kg?1, in propofol–isoflurane anesthetized dogs. IM dexmedetomidine given 108 ± 2 minutes before onset of infusion showed typical significant effects on cardiovascular parameters.  相似文献   

5.
ObjectiveTo determine the effects of intravenous (IV) magnesium sulphate (MgSO4) as a bolus followed by a constant rate infusion (CRI) on anaesthetic requirements, neuroendocrine stress response to surgery, haemostasis and postoperative analgesia in healthy dogs undergoing ovariohysterectomy.Study designBlinded randomized clinical trial.AnimalsSixteen female dogs.MethodsAfter intramuscular premedication with acepromazine (0.05 mg kg?1) and morphine (0.3 mg kg?1), anaesthesia was induced with diazepam (0.2 mg kg?1) and propofol (2 mg kg?1) intravenously and maintained with isoflurane in oxygen in all dogs. Dogs were randomly assigned to two groups, M and C. Group M received MgSO4 (50 mg kg?1 over 15 minutes, followed by a 15 mg kg?1 hour?1 CRI). Group C received an equivalent bolus and CRI of lactated Ringer's solution. In addition, all dogs received lactated Ringer's solution (10 mL kg?1 over 15 minutes followed by 10 mL kg?1 hour?1). End-tidal isoflurane and carbon dioxide tensions, cardio-respiratory variables, arterial blood gases, electrolytes, ACTH and cortisol concentrations were measured at different time points. Thromboelastography (TEG) was performed pre- and post-anaesthesia. Postoperative pain was evaluated using the short form of the Glasgow Composite Pain Scale. Data were analysed with repeated measures anova and Mann–Whitney U tests (p< 0.05).ResultsNo statistically significant differences between groups were found in any of the measured variables. However, the alpha angle and maximal amplitude recorded by TEG in group M were significantly increased post-anaesthesia, but remained within the reference interval. One dog in Group M and two in Group C received rescue analgesia during recovery.Conclusions and clinical relevanceAs used in this study, MgSO4 failed to decrease isoflurane requirements, postoperative pain and stress hormone concentrations; however, it did not produce any cardio-respiratory or major haemostatic side effects. Administration of intravenous MgSO4 together with an opioid during ovariohysterectomy in dogs does not seem to provide any clinical advantage.  相似文献   

6.
ObjectiveTo compare the efficacy and cardiopulmonary effects of propofol and fentanyl, with propofol and midazolam for total intravenous anaesthesia.Study designProspective, randomized, crossover experimental study.AnimalsSix goats; three does and three wethers.MethodsGoats received either fentanyl 0.02 mg kg?1 (treatment FP) or midazolam 0.3 mg kg?1 (treatment MP) intravenously. One minute later anaesthesia was induced with propofol, then maintained by constant rate infusion of propofol 12.0 mg kg?1 hour?1 and fentanyl 0.02 mg kg?1 hour?1 (treatment FP) or propofol 12.0 mg kg?1 hour?1 and midazolam 0.3 mg kg?1 hour?1 (treatment MP) for 90 minutes. Response to noxious stimulus was tested every 10 minutes and propofol dose adjusted to prevent purposeful movement. Cardiopulmonary parameters were measured continuously, and arterial blood-gas analysis performed intermittently. Recovery was timed and quality scored. Results are presented as median (IQR).ResultsDifferences in the propofol induction dose [4.00 (3.96-4.01) and 3.97 (3.91-4.00) mg kg?1 for treatments FP and MP, respectively] were not significant. Quality of induction in both groups was smooth. The median propofol dose for maintenance was less (p = 0.004) with treatment FP (12.0 mg kg?1 hour?1) than MP (18.0 mg kg?1 hour?1). Cardiopulmonary function was well maintained with both treatments. Recovery times in minutes from the end of anaesthetic infusion for treatments FP and MP respectively were; to extubation 3.0 (3.0-3.0) and 4.5 (3.3-5.0); to sternal position, 4.5 (3.3-5.0) and 5.0 (5.0-6.5) and to standing 13.0 (10.3-15.0) and 15.0 (11.3-17.3). Quality of recovery was acceptable in both groups, but abnormal behavioural signs were observed after treatment FP.Conclusions and clinical relevanceTotal intravenous anaesthesia with propofol and fentanyl or propofol and midazolam, at the doses studied, in spontaneously-breathing, oxygen-supplemented goats is practicable. Recovery from the fentanyl-propofol combination is not always smooth.  相似文献   

7.
ObjectiveThe objectives of this study were to determine the effects of fentanyl on the end-tidal concentration of sevoflurane needed to prevent motor movement (MACNM) in response to noxious stimulation, and to evaluate if acute tolerance develops.Study designRandomized cross-over experimental study.AnimalsSix healthy, adult (2–3 years old), intact male, mixed-breed dogs weighing 16.2 ± 1.1 kg.MethodsSix dogs were randomly assigned to receive one of three separate treatments over a 3 week period. After baseline sevoflurane MACNM (MACNM-B) determination, fentanyl treatments (T) were administered as a loading dose (Ld) and constant rate infusion (CRI) as follows: T1-Ld of 7.5 μg kg?1 and CRI at 3 μg kg?1 hour?1; T2-Ld of 15 μg kg?1 and CRI at 6.0 μg kg ?1 hour?1; T3-Ld of 30 μg kg?1 and CRI at 12 μg kg?1 hour?1. The MACNM was defined as the minimum end-tidal sevoflurane concentration preventing motor movement. The first post-treatment MACNM (MACNM-I) determination was initiated 90 minutes after the start of the CRI, and a second MACNM (MACNM-II) determination was initiated 3 hours after MACNM-I was established.ResultsThe overall least square mean MACNM-B for all groups was 2.66%. All treatments decreased (p < 0.05) MACNM, and the decrease from baseline was 22%, 35% and 41% for T1, T2 and T3, respectively. Percentage change in T1 differed (p < 0.05) from T2 and T3; however, T2 did not differ from T3. MACNM-I was not significantly different from MACNM-II within treatments.Conclusions and clinical relevanceFentanyl doses in the range of 3–12 μg kg?1 hour?1 significantly decreased the sevoflurane MACNM. Clinically significant tolerance to fentanyl did not occur under the study conditions.  相似文献   

8.
ObjectiveTo compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those of morphine alone on the minimum end-tidal sevoflurane concentration necessary to prevent movement (MACNM) in ponies.Study designProspective, randomized, crossover, ‘blinded’, experimental study.AnimalsFive healthy adult gelding ponies were anaesthetized twice with a 3-week washout period.MethodsAfter induction of anaesthesia with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (Fe‘SEVO 2.5%) in 55% oxygen. Monitoring included pulse oximetry, electrocardiography and measurement of anaesthetic gases, arterial blood pressure and body temperature. The ponies were mechanically ventilated and randomly allocated to receive IV treatment M [morphine 0.15 mg kg?1 (T10-T15) followed by a CRI (0.1 mg kg?1 hour?1)] or treatment DM [dexmedetomidine 3.5 μg kg?1 plus morphine 0.15 mg kg?1 (T10-T15) followed by a CRI of dexmedetomidine 1.75 μg kg?1 hour?1 and morphine 0.1 mg kg?1 hour?1]. At T60, a stepwise MACNM determination was initiated using constant current electrical stimuli at the skin of the lateral pastern region. Triplicate MACNM estimations were obtained and then averaged in each pony. Wilcoxon signed-rank test was used to detect differences in MAC between treatments (a = 0.05).ResultsSevoflurane-morphine MACNM values (median (range) and mean ± SD) were 2.56 (2.01–4.07) and 2.79 ± 0.73%. The addition of a continuous infusion of dexmedetomidine significantly reduced sevoflurane MACNM values to 0.89 (0.62–1.05) and 0.89 ± 0.22% (mean MACNM reduction 67 ± 11%).Conclusion and clinical relevanceCo-administration of dexmedetomidine and morphine CRIs significantly reduced the MACNM of sevoflurane compared with a CRI of morphine alone at the reported doses.  相似文献   

9.
ObjectiveTo compare the clinical usefulness of constant rate infusion (CRI) protocols of romifidine with or without butorphanol for sedation of horses.Study designProspective ‘blinded’ controlled trial using block randomization.AnimalsForty healthy Freiberger stallions.MethodsThe horses received either intravenous (IV) romifidine (loading dose: 80 μg kg?1; infusion: 30 μg kg?1 hour?1) (treatment R, n = 20) or romifidine combined with butorphanol (romifidine loading: 80 μg kg?1; infusion: 29 μg kg?1 hour?1, and butorphanol loading: 18 μg kg?1; infusion: 25 μg kg?1 hour?1) (treatment RB, n = 20). Twenty-one horses underwent dentistry and ophthalmic procedures, while 19 horses underwent only ophthalmologic procedure and buccal examination. During the procedure, physiologic parameters and occurrence of head/muzzle shaking or twitching and forward movement were recorded. Whenever sedation was insufficient, additional romifidine (20 μg kg?1) was administered IV. Recovery time was evaluated by assessing head height above ground. At the end of the procedure, overall quality of sedation for the procedure was scored by the dentist and anaesthetist using a visual analogue scale. Statistical analyses used two-way anova or linear mixed models as relevant.ResultsSedation quality scores as assessed by the anaesthetist were R: median 7.55, range: 4.9–9.0 cm, RB: 8.8, 4.7–10.0 cm, and by the dentist R: 6.6, 3.0–8.2 cm, RB: 7.9, 6.6–8.8 cm. Horses receiving RB showed clinically more effective sedation as demonstrated by fewer poor scores and a tendency to reduced additional drug requirements. More horses showed forward movement and head shaking in treatment RB than treatment R. Three horses (two RB, one R) had symptoms of colic following sedation.Conclusions and clinical relevanceThe described protocols provide effective sedation under clinical conditions but for dentistry procedures, the addition of butorphanol is advantageous.  相似文献   

10.
ObjectiveVarious drugs administered to horses undergoing surgical procedures can release histamine. Histamine concentrations were evaluated in horses prepared for surgery and administered butorphanol or morphine intraoperative infusions.Study designProspective studies with one randomized.AnimalsA total of 44 client-owned horses.MethodsIn one study, anesthesia was induced with xylazine followed by ketamine–diazepam. Anesthesia was maintained with guaifenesin–xylazine–ketamine (GXK) during surgical preparation. For surgery, isoflurane was administered with intravenous (IV) morphine (group M: 0.15 mg kg–1 and 0.1 mg kg–1 hour–1; 15 horses) or butorphanol (group B: 0.05 mg kg–1 and 0.01 mg kg–1 hour–1; 15 horses). Histamine and morphine concentrations were measured using enzyme-linked immunoassay before opioid injection (time 0), and after 1, 2, 5, 30, 60 and 90 minutes. In a subsequent study, plasma histamine concentrations were measured in 14 horses before drug administration (baseline), 15 minutes after IV sodium penicillin and 15 minutes after starting GXK IV infusion. Statistical comparison was performed using anova for repeated measures. Pearson correlation compared morphine and histamine concentrations. Data are presented as mean ± standard deviation. Significance was assumed when p ≤ 0.05.ResultsWith histamine, differences occurred between baseline (3.2 ± 2.4 ng mL–1) and GXK (5.2 ± 7.1 ng mL–1) and between baseline and time 0 in group B (11.9 ± 13.4 ng mL–1) and group M (11.1 ± 12.4 ng mL–1). No differences occurred between baseline and after penicillin or between groups M and B. Morphine concentrations were higher at 1 minute following injection (8.1 ± 5.1 ng mL–1) than at 30 minutes (4.9 ± 3.1 ng mL–1) and 60 minutes (4.0 ± 2.5 ng mL–1). Histamine correlated with morphine at 2, 30 and 60 minutes.Conclusions and clinical relevanceGXK increased histamine concentration, but concentrations were similar with morphine and butorphanol.  相似文献   

11.
ObjectiveTo determine the induction doses, then minimum infusion rates of alfaxalone for total intravenous anaesthesia (TIVA), and subsequent, cardiopulmonary effects, recovery characteristics and alfaxalone plasma concentrations in cats undergoing ovariohysterectomy after premedication with butorphanol-acepromazine or butorphanol-medetomidine.Study designProspective randomized blinded clinical study.AnimalsTwenty-eight healthy cats.MethodsCats undergoing ovariohysterectomy were assigned into two groups: together with butorphanol [0.2 mg kg?1 intramuscularly (IM)], group AA (n = 14) received acepromazine (0.1 mg kg?1 IM) and group MA (n = 14) medetomidine (20 μg kg?1 IM). Anaesthesia was induced with alfaxalone to effect [0.2 mg kg?1 intravenously (IV) every 20 seconds], initially maintained with 8 mg kg?1 hour?1 alfaxalone IV and infusion adjusted (±0.5 mg kg?1 hour?1) every five minutes according to alterations in heart rate (HR), respiratory rate (fR), Doppler blood pressure (DBP) and presence of palpebral reflex. Additional alfaxalone boli were administered IV if cats moved/swallowed (0.5 mg kg?1) or if fR >40 breaths minute?1 (0.25 mg kg?1). Venous blood samples were obtained to determine plasma alfaxalone concentrations. Meloxicam (0.2 mg kg?1 IV) was administered postoperatively. Data were analysed using linear mixed models, Chi-squared, Fishers exact and t-tests.ResultsAlfaxalone anaesthesia induction dose (mean ± SD), was lower in group MA (1.87 ± 0.5; group AA: 2.57 ± 0.41 mg kg?1). No cats became apnoeic. Intraoperative bolus requirements and TIVA rates (group AA: 11.62 ± 1.37, group MA: 10.76 ± 0.96 mg kg?1 hour?1) did not differ significantly between groups. Plasma concentrations ranged between 0.69 and 10.76 μg mL?1. In group MA, fR, end-tidal carbon dioxide, temperature and DBP were significantly higher and HR lower.Conclusion and clinical relevanceAlfaxalone TIVA in cats after medetomidine or acepromazine sedation provided suitable anaesthesia with no need for ventilatory support. After these premedications, the authors recommend initial alfaxalone TIVA rates of 10 mg kg?1 hour?1.  相似文献   

12.
ObjectiveTo investigate motor and cardiovascular responses to dexmedetomidine or fentanyl in isoflurane-anaesthetized pigs.Study designExperimental, balanced, block randomized, two-group design.AnimalsA group of 16 crossbred pigs, 55 ± 8 days (mean ± standard deviation) old.MethodsDeltoid electromyography (EMG) was recorded during isoflurane anaesthesia. Electrical stimulation using 5, 10, 20 and 40 mA of the distal right thoracic limb elicited a nociceptive withdrawal reflex (NWR), quantified by the area under the curve (AUC) for the simulation intensity versus EMG amplitude response curve. Latency to movement evoked by clamping a claw for maximum 60 seconds was noted. Arterial blood pressure and pulse rate were recorded. Data were sampled at baseline and during dexmedetomidine 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 μg kg–1 hour–1 or fentanyl 5, 10, 20, 40, 80 and 160 μg kg–1 hour–1 infusions. The influence of infusion rate on NWR AUC and spontaneous EMG was analysed using a mixed model, with p < 5%.ResultsNWR AUC increased at fentanyl 5 μg kg–1 hour–1 but decreased at fentanyl 40, 80 and 160 μg kg–1 hour–1 and dexmedetomidine 4.0 and 8.0 μg kg–1 hour–1. All pigs at fentanyl 80 μg kg–1 hour–1, and three pigs at dexmedetomidine 8.0 μg kg–1 hour–1 had mechanical latencies greater than 60 seconds. Spontaneous EMG activity increased accompanied by visually evident ‘shivering’ at fentanyl 5, 10 and 20 μg kg–1 hour–1 but decreased at dexmedetomidine 2, 4 and 8 μg kg–1 hour–1. Clinically relevant effects of increasing infusion rates on blood pressure or pulse rate were not observed.Conclusion and clinical relevanceIf anaesthetic plane or antinociception is evaluated in pigs, response to claw clamping and NWR will not necessarily give uniform results when comparing drugs. If only one method is used, results should be interpreted cautiously.  相似文献   

13.
ObjectiveTo evaluate perioperative stress-related hormones in isoflurane-anesthetized horses administered infusions of dexmedetomidine alone or with butorphanol or remifentanil, compared with ketamine–morphine.Study designRandomized, prospective, nonblinded clinical study.AnimalsA total of 51 horses undergoing elective surgical procedures.MethodsHorses were premedicated with xylazine, anesthesia induced with ketamine–diazepam and maintained with isoflurane and one of four intravenous infusions. Partial intravenous anesthesia (PIVA) was achieved with dexmedetomidine (1.0 μg kg–1 hour–1; group D; 12 horses); dexmedetomidine (1.0 μg kg–1 hour–1) and butorphanol bolus (0.05 mg kg–1; group DB; 13 horses); dexmedetomidine (1.0 μg kg–1 hour–1) and remifentanil (3.0 μg kg–1 hour–1; group DR; 13 horses); or ketamine (0.6 mg kg–1 hour–1) and morphine (0.15 mg kg–1, 0.1 mg kg–1 hour–1; group KM; 13 horses). Infusions were started postinduction; butorphanol bolus was administered 10 minutes before starting surgery. Blood was collected before drugs were administered (baseline), 10 minutes after ketamine–diazepam, every 30 minutes during surgery and 1 hour after standing. Mean arterial pressure (MAP), pulse rate, end-tidal isoflurane concentration, cortisol, nonesterified fatty acids (NEFA), glucose and insulin concentrations were compared using linear mixed models. Significance was assumed when p < 0.05.ResultsWithin D, cortisol was lower at 120–180 minutes from starting surgery compared with baseline. Cortisol was higher in KM than in D at 60 minutes from starting surgery. Within all groups, glucose was higher postinduction (except DR) and 60 minutes from starting surgery, and insulin was lower during anesthesia and higher after standing compared with baseline. After standing, NEFA were higher in KM than in DB. In KM, MAP increased at 40–60 minutes from starting surgery compared with 30 minutes postinduction.Conclusions and clinical relevanceDexmedetomidine suppressed cortisol release more than dexmedetomidine–opioid and ketamine–morphine infusions. Ketamine–morphine PIVA might increase catecholamine activity.  相似文献   

14.
ObjectiveTo evaluate the output temperature of a dry heat fluid warmer at fluid rates typically used in small animal veterinary patients.Study designProspective in vitro study.AnimalsNone.MethodsAmbient temperature lactated Ringer’s (17.9-18.8 °C) was delivered via a dry heat fluid warmer. A temperature probe was used to measure fluid outflow temperature from the compatible giving set at 5, 10, 20, 50, 70, 80, 100, 200, 300, 400 and 500 mL hour–1. Outflow fluid temperature at plateau (two consecutive readings within 0.1 °C) was compared with baseline fluid temperature (fluid warmer turned off) to calculate temperature changes at each rate. Kruskal–Wallis test was used to compare changes in temperature and time to plateau temperature. Dunn’s post hoc test was used to test for significant differences in temperature compared to 5 mL hour–1; p value < 0.05.ResultsMedian plateau outflow temperature increased as fluid rate increased, with temperatures of 18.5, 18.6, 18.7, 18.8, 19.4, 19.4, 21.5, 25.3, 28.5, 30.7 and 32.6 °C, at flow rates of 5, 10, 20, 50, 70, 80, 100, 200, 300, 400 and 500 mL hour–1. Fluid rates > 100 mL hour–1 showed significant increases from baseline (p = 0.021) There was no difference in temperature change from baseline at fluid rates < 100 mL hour–1 (p > 0.05). Compared to plateau temperature at 5 mL hour-1, there was a statistical difference in plateau temperature above 100 mL hour–1 (p = 0.0207). Maximum outflow plateau temperature was 32.6 °C at 500 mL hour–1.Conclusions and clinical relevanceA dry heat fluid warmer has significantly decreased efficacy at low fluid rates, with no statistically significant increase in fluid temperature at fluid rates below 100 mL hour–1 at the end of a compatible fluid line. Inline dry heat fluid warmers are ineffective at fluid rates below 100 mL hour–1.  相似文献   

15.
ObjectiveTo elaborate constant rate infusion (CRI) protocols for xylazine (X) and xylazine/butorphanol (XB) which will result in constant sedation and steady xylazine plasma concentrations.Study designBlinded randomized experimental study.AnimalsTen adult research horses.MethodsPart I: After normal height of head above ground (HHAG = 100%) was determined, a loading dose of xylazine (1 mg kg?1) with butorphanol (XB: 18 μg kg?1) or saline (X: equal volume) was given slowly intravenously (IV). Immediately afterwards, a CRI of butorphanol (XB: 25 μg kg?1 hour?1) or saline (X) was administered for 2 hours. The HHAG was used as a marker of depth of sedation. Sedation was maintained for 2 hours by additional boluses of xylazine (0.3 mg kg?1) whenever HHAG >50%. The dose of xylazine (mg kg?1 hour?1) required to maintain sedation was calculated for both groups. Part II: After the initial loading dose, the calculated xylazine infusion rates were administered in parallel to butorphanol (XB) or saline (X) and sedation evaluated. Xylazine plasma concentrations were measured by HPLC-MS-MS at time points 0, 5, 30, 45, 60, 90, and 120 minutes. Data were analyzed using paired t-test, Wilcoxon signed rank test and a 2-way anova for repeated measures (p < 0.05).ResultsThere was no significant difference in xylazine requirements (X: 0.69, XB: 0.65 mg kg?1 hour?1) between groups. With treatment X, a CRI leading to prolonged sedation was developed. With XB, five horses (part I: two, part II: three) fell down and during part II four horses appeared insufficiently sedated. Xylazine plasma concentrations were constant after 45 minutes in both groups.ConclusionXylazine bolus, followed by CRI, provided constant sedation. Additional butorphanol was ineffective in reducing xylazine requirements and increased ataxia and apparent early recovery from sedation in unstimulated horses.Clinical relevanceData were obtained on unstimulated healthy horses and extrapolation to clinical conditions requires caution.  相似文献   

16.
ObjectiveTo compare the postoperative analgesic effects of intravenous (IV) lidocaine, meloxicam, and their combination in dogs undergoing ovariohysterectomy.Study designProspective, randomized, double‐blind, controlled clinical trial.AnimalsTwenty‐seven dogs aged (mean ± SD) 16.1 ± 7.5 months and weighing 22.4 ± 17.9 kg scheduled for ovariohysterectomy.MethodsAnaesthesia was induced with propofol and maintained with isoflurane. Dogs (n = 9 in each group) were allocated to receive just prior to and during surgery one of the following regimens: M group, 0.2 mg kg?1 IV meloxicam then a continuous rate infusion (CRI) of lactated Ringer's at 10 mL kg?1 hour?1; L group, a bolus of lidocaine (1 mg kg?1 IV) then a CRI of lidocaine at 0.025 mg kg?1 minute?1; and M + L group, both the above meloxicam and lidocaine treatments. Pain and sedation were scored, and venous samples taken for serum cortisol and glucose measurement before and at intervals for 12 hours after anaesthesia. Pain scores were assessed using a multi‐parameter subjective scoring scale (cumulative scale 0–21) by three observers. The protocol stated that dogs with a total score exceeding 9 or a sub‐score above 3 in any one category would receive rescue analgesia. Sedation was scored on a scale of 0–4.ResultsThere were no significant differences in subjective pain scores, serum cortisol, and glucose concentrations between the three groups. The highest pain score at any time was 5, and no dog required rescue analgesia. None of the three regimens caused any observable side effects during or after anaesthesia. At 1 and 2 hours after extubation dogs in group L were significantly more sedated than in the other two groups.Conclusions and Clinical relevanceThis study suggests that, with the scoring system used, IV lidocaine and meloxicam provide similar and adequate post‐operative analgesia in healthy dogs undergoing ovariohysterectomy.  相似文献   

17.
ObjectiveTo compare dexmedetomidine and fentanyl constant rate infusions in anesthetic protocols for septic dogs with pyometra, using microcirculatory, hemodynamic and metabolic variables.Study designRandomized clinical study.AnimalsA total of 33 dogs with pyometra with two or more systemic inflammatory response syndrome variables undergoing ovariohysterectomy.MethodsDogs were randomized into two groups: group DG, dexmedetomidine (3 μg kg–1 hour–1; 17 dogs) and group FG, fentanyl (5 μg kg–1 hour–1; 16 dogs) infused during isoflurane anesthesia and mechanical ventilation. Microcirculation flow index (MFI), total vessel density and De Backer score were assessed using orthogonal polarization spectral imaging at the sublingual site. Heart rate, invasive blood pressure, temperature, arterial blood gas analysis and lactate concentration were obtained at various time points. Variables were recorded at baseline (BL), immediately before (T0), 30 (T30) and 60 (T60) minutes after infusion, and 60 minutes after surgery. Data were analyzed using the Shapiro-Wilk test. To compare variables between groups, the unpaired Student t test was used. Comparison between evaluation time points was performed with two-way anova for repeated measures. Where statistical significance was detected, the Bonferroni post hoc test was used.ResultsMFI was significantly higher in group FG at T30. Mean arterial pressure at T30 was higher in group DG (89 ± 15 mmHg) than in group FG (72 ± 13 mmHg). Lactate concentrations were not significantly different between groups at each time point. Both groups had similar clinical outcomes (mortality, extubation time and occurrence of hypotension and bradyarrhythmias).Conclusions and clinical relevanceDexmedetomidine (3 μg kg–1 hour–1) without a loading dose can be included in the maintenance of anesthesia in dogs with pyometra and sepsis without compromising microcirculation and hemodynamic values when compared with fentanyl (5 μg kg–1 hour–1).  相似文献   

18.
ObjectiveTo compare pulmonary function and gas exchange in ponies during maintenance of anaesthesia with isoflurane or by a total intravenous anaesthesia (TIVA) technique.Study designExperimental, cross–over study.AnimalsSix healthy ponies weighing mean 286 (range 233–388) ± SD 61 kg, age 13 (9-16) ± 3 years.MethodsThe ponies were anaesthetized twice, a minimum of two weeks apart. Following sedation with romifidine [80 μg kg?1 intravenously (IV)], anaesthesia was induced IV with midazolam (0.06 mg kg?1) and ketamine (2.5 mg kg?1), then maintained either with inhaled isoflurane (Fe’Iso = 1.1 vol%) (T-ISO) or an IV infusion of romifidine (120 μg kg?1 hour?1), midazolam (0.09 mg kg?1 hour?1 IV) and ketamine (3.3 mg kg?1 hour?1) (T-TIVA). Ponies were placed in lateral recumbency. Breathing was spontaneous and Fi’O2 60%. After an instrumentation/stabilisation period of 30 minutes, arterial and mixed venous blood samples were taken simultaneously every 10 minutes for 60 minutes and analysed immediately. Oxygen extraction ratio (O2ER) and venous admixture were calculated. Tidal volume (TV), minute volume (MV), respiratory rate (fR), packed cell volume (PCV), arterial blood pressure and heart rate (HR) were measured and recorded. Data were analysed with mixed model anova (a = 0.05). Treatments were compared overall and at two selected time points (T30 and T60) using Bonferroni correction.ResultsArterial and mixed venous partial pressures of O2 and CO2, and TV were significantly lower and MV and fR were higher in T-TIVA compared to T-ISO. Venous admixture did not differ between treatments. O2ER was significantly higher in T-TIVA. Mean arterial pressure was higher and HR was lower in T-TIVA compared to T-ISO.Conclusions and clinical relevanceWhilst arterial CO2 was within an acceptable range during both protocols, the impairment of oxygenation was more pronounced with the T-TIVA evidenced by lower arterial and venous oxygen partial pressures.  相似文献   

19.
ObservationsA 9 year-old, 40 kg, female spayed Bouvier des Flandres was anesthetized for surgical removal of an intra-cardiac mass. Pre-anesthetic work-up included thoracic radiographs, which revealed moderate pleural effusion, and cardiac ultrasound, which identified a mass attached to the wall of the right ventricular outflow tract (RVOT). The mass caused dynamic obstruction of the RVOT during systole. The dog was pre-medicated with intravenous (IV) hydromorphone (0.05 mg kg?1). Following pre-oxygenation, anesthesia was induced with ketamine (3.75 mg kg?1, IV) and diazepam (0.18 mg kg?1, IV). Anesthesia was maintained with isoflurane in oxygen, an intravenous constant rate infusion (CRI) of fentanyl (10–30 μg kg?1 hour?1) and a CRI of lidocaine (50–200 μg kg?1 minute?1). A right lateral thoracotomy was performed. The heart was stopped transiently with a cold cardioplegic solution for 7.83 minutes to allow the removal of the mass through an open-heart procedure. No cardiopulmonary bypass was used. The heart was successfully restarted after cardiopulmonary resuscitation with internal cardiac massage and internal defibrillation. The dog recovered uneventfully from anesthesia without any apparent neurological sequelae. Post-operative analgesia consisted of intercostal nerve blocks with bupivacaine, CRIs of fentanyl (2–5 μg kg?1 hour?1) and lidocaine (40 μg kg?1 minute?1) and with oral meloxicam (0.1 mg kg?1). Five days following surgery, the dog was discharged from the hospital. Histopathology and immunohistochemistry of the mass identified an ectopic thyroid carcinoma.ConclusionsThis case showed the feasibility of whole body hypothermia and using a cold cardioplegic solution to induce cardiac arrest for a short open-heart procedure.  相似文献   

20.
ObjectiveTo investigate changes in colloid osmotic pressure (COP), total protein (TP) and osmolality (OSM) during anesthesia in horses given intravenous lactated Ringer’s solution (LRS) or LRS and hetastarch (HES).Study designProspective, clinical trial.AnimalsFourteen horses presented for surgery. Mean age 8.3 ± 1.9 years; mean weight 452 ± 25 kg.MethodsHorses were premedicated with xylazine intravenously (IV); anesthesia was induced with ketamine and diazepam IV, and maintained with sevoflurane. Butorphanol was administered IV with pre-medications or immediately after induction. Xylazine was administered IV for recovery if necessary. LRS was administered IV to all horses with a target rate of 5–10 mL kg?1 hour?1. Half of the horses also received 6% HES, 2.5 mL kg?1 over 1 hour in addition to LRS. Horses that received LRS only were considered the LRS group. Horses that received both LRS and HES were considered the LRS/HES group. Blood was drawn pre- and post-anesthesia, immediately following induction, and every 30 minutes throughout anesthesia. COP, TP and OSM were measured.ResultsCOP and TP significantly decreased at similar rates for both treatment groups from pre-anesthetic values. Pre-anesthetic COP was significantly greater in the LRS group when compared to the LRS/HES group pre-, post- and throughout anesthesia. In the LRS group post-anesthetic OSM was significantly different than the pre-anesthesia value and that for the LRS/HES group.Conclusions and clinical relevanceAdministration of IV HES (2.5 mL kg?1, over 1 hour) in combination with LRS does not attenuate the decrease in COP typically seen during anesthesia with crystalloid administration alone. Based on these results, administration of HES at this rate and total volume would not be expected to prevent fluid shifts into the interstitium through its effects on COP.  相似文献   

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