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1.
ObjectiveTo evaluate the effects of a constant rate infusion (CRI) of lidocaine alone or in combination with ketamine on the minimum infusion rate (MIR) of propofol in dogs and to compare the hemodynamic effects produced by propofol, propofol-lidocaine or propofol-lidocaine-ketamine anesthesia.Study designProspective, randomized cross-over experimental design.AnimalsFourteen adult mixed-breed dogs weighing 15.8 ± 3.5 kg.MethodsEight dogs were anesthetized on different occasions to determine the MIR of propofol alone and propofol in combination with lidocaine (loading dose [LD] 1.5 mg kg?1, CRI 0.25 mg kg?1 minute?1) or lidocaine (LD 1.5 mg kg?1, CRI 0.25 mg kg?1 minute?1) and ketamine (LD 1 mg kg?1, CRI 0.1 mg kg?1 minute?1). In six other dogs, the hemodynamic effects and bispectral index (BIS) were investigated. Each animal received each treatment (propofol, propofol-lidocaine or propofol-lidocaine-ketamine) on the basis of the MIR of propofol determined in the first set of experiments.ResultsMean ± SD MIR of propofol was 0.51 ± 0.08 mg kg?1 minute?1. Lidocaine-ketamine significantly decreased the MIR of propofol to 0.31 ± 0.07 mg kg?1 minute?1 (37 ± 18% reduction), although lidocaine alone did not (0.42 ± 0.08 mg kg?1 minute?1, 18 ± 7% reduction). Hemodynamic effects were similar in all treatments. Compared with the conscious state, in all treatments, heart rate, cardiac index, mean arterial blood pressure, stroke index and oxygen delivery index decreased significantly, whereas systemic vascular resistance index increased. Stroke index was lower in dogs treated with propofol-lidocaine-ketamine at 30 minutes compared with propofol alone. The BIS was lower during anesthesia with propofol-lidocaine-ketamine compared to propofol alone.Conclusions and clinical relevanceLidocaine-ketamine, but not lidocaine alone, reduced the MIR of propofol in dogs. Neither lidocaine nor lidocaine in combination with ketamine attenuated cardiovascular depression produced by a continuous rate infusion of propofol.  相似文献   

2.
ObjectiveTo evaluate the effects of intravenous lidocaine (L) and ketamine (K) alone and their combination (LK) on the minimum alveolar concentration (MAC) of sevoflurane (SEVO) in dogs.Study designProspective randomized, Latin-square experimental study.AnimalsSix, healthy, adult Beagles, 2 males, 4 females, weighing 7.8 – 12.8 kg.MethodsAnesthesia was induced with SEVO in oxygen delivered by face mask. The tracheas were intubated and the lungs ventilated to maintain normocapnia. Baseline minimum alveolar concentration of SEVO (MACB) was determined in duplicate for each dog using an electrical stimulus and then the treatment was initiated. Each dog received each of the following treatments, intravenously as a loading dose (LD) followed by a constant rate infusion (CRI): lidocaine (LD 2 mg kg−1, CRI 50 μg kg−1minute−1), lidocaine (LD 2 mg kg−1, CRI 100 μgkg−1 minute−1), lidocaine (LD 2 mg kg−1, CRI 200 μg kg−1 minute−1), ketamine (LD 3 mg kg−1, CRI 50 μg kg−1 minute−1), ketamine (LD 3 mgkg−1, CRI 100 μg kg−1 minute−1), or lidocaine (LD 2 mg kg−1, CRI 100 μg kg−1 minute−1) + ketamine (LD 3 mg kg−1, CRI 100 μg kg−1 minute−1) in combination. Post-treatment MAC (MACT) determination started 30 minutes after initiation of treatment.ResultsLeast squares mean ± SEM MACB of all groups was 1.9 ± 0.2%. Lidocaine infusions of 50, 100, and 200 μg kg−1 minute−1 significantly reduced MACB by 22.6%, 29.0%, and 39.6%, respectively. Ketamine infusions of 50 and 100 μg kg−1 minute−1 significantly reduced MACB by 40.0% and 44.7%, respectively. The combination of K and L significantly reduced MACB by 62.8%.Conclusions and clinical relevanceLidocaine and K, alone and in combination, decrease SEVO MAC in dogs. Their use, at the doses studied, provides a clinically important reduction in the concentration of SEVO during anesthesia in dogs.  相似文献   

3.
ObjectiveTo evaluate the postoperative analgesic effects of a constant rate infusion (CRI) of either fentanyl (FENT), lidocaine (LIDO), ketamine (KET), dexmedetomidine (DEX), or the combination lidocaine-ketamine-dexmedetomidine (LKD) in dogs.Study designRandomized, prospective, blinded, clinical study.AnimalsFifty-four dogs.MethodsAnesthesia was induced with propofol and maintained with isoflurane. Treatments were intravenous (IV) administration of a bolus at start of anesthesia, followed by an IV CRI until the end of anesthesia, then a CRI at a decreased dose for a further 4 hours: CONTROL/BUT (butorphanol 0.4 mg kg−1, infusion rate of saline 0.9% 2 mLkg−1 hour−1); FENT (5 μg kg−1, 10 μg kg−1hour−1, then 2.5 μg kg−1 hour−1); KET (1 mgkg−1, 40 μg kg−1 minute−1, then 10 μg kg−1minute−1); LIDO (2 mg kg−1, 100 μg kg−1 minute−1, then 25 μg kg−1 minute−1); DEX (1 μgkg−1, 3 μg kg−1 hour−1, then 1 μg kg−1 hour−1); or a combination of LKD at the aforementioned doses. Postoperative analgesia was evaluated using the Glasgow composite pain scale, University of Melbourne pain scale, and numerical rating scale. Rescue analgesia was morphine and carprofen. Data were analyzed using Friedman or Kruskal–Wallis test with appropriate post-hoc testing (p < 0.05).ResultsAnimals requiring rescue analgesia included CONTROL/BUT (n = 8), KET (n = 3), DEX (n = 2), and LIDO (n = 2); significantly higher in CONTROL/BUT than other groups. No dogs in LKD and FENT groups received rescue analgesia. CONTROL/BUT pain scores were significantly higher at 1 hour than FENT, DEX and LKD, but not than KET or LIDO. Fentanyl and LKD sedation scores were higher than CONTROL/BUT at 1 hour.Conclusions and clinical relevanceLKD and FENT resulted in adequate postoperative analgesia. LIDO, CONTROL/BUT, KET and DEX may not be effective for treatment of postoperative pain in dogs undergoing ovariohysterectomy.  相似文献   

4.
ObjectiveTo determine the anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in sheep anaesthetized with isoflurane and undergoing orthopaedic surgery.Study designProspective, randomised, ‘blinded’ controlled study.AnimalsTwenty healthy sheep (weight mean 41.1 ± SD 4.5 kg).MethodsSheep were sedated with intravenous (IV) dexmedetomidine (4 μg kg−1) and morphine (0.2 mg kg−1). Anaesthesia was induced with propofol (1 mg kg−1 minute−1 to effect IV) and maintained with isoflurane in oxygen and a continuous rate infusion (CRI) of fentanyl 10 μg kg−1 hour−1 (group F) or saline (group P) for 100 minutes. The anaesthetic induction dose of propofol, isoflurane expiratory fraction (Fe’iso) required for maintenance and cardiorespiratory measurements were recorded and blood gases analyzed at predetermined intervals. The quality of recovery was assessed. Results were compared between groups using t-tests or Mann–Whitney as relevant.ResultsThe propofol induction dose was 4.7 ± 2.4 mg kg−1. Fe’iso was significantly lower (by 22.6%) in group F sheep than group P (p = 0). Cardiac index (mean ± SD mL kg−1 minute−1) was significantly (p = 0.012) lower in group F (90 ± 15) than group P (102 ± 35). Other measured cardiorespiratory parameters did not differ statistically significantly between groups. Recovery times and recovery quality were statistically similar in both groups.Conclusions and clinical relevanceFentanyl reduced isoflurane requirements without clinically affecting the cardiorespiratory stability or post-operative recovery in anaesthetized sheep undergoing orthopaedic surgery.  相似文献   

5.
ObjectiveTo investigate intravenous (IV) propofol given by intermittent boluses or by continuous rate infusion (CRI) for anaesthesia in swans.Study designProspective randomized clinical study.AnimalsTwenty mute swans (Cygnus olor) (eight immature and 12 adults) of unknown sex undergoing painless diagnostic or therapeutic procedures.MethodsInduction of anaesthesia was with 8 mg kg?1 propofol IV. To maintain anaesthesia, ten birds (group BOLI) received propofol as boluses, whilst 10 (group CRI) received propofol as a CRI. Some physiological parameters were measured. Anaesthetic duration was 35 minutes. Groups were compared using Mann–Whitney U-test. Results are median (range).ResultsAnaesthetic induction was smooth and tracheal intubation was achieved easily in all birds. Bolus dose in group BOLI was 2.9 (1.3–4.3) mg kg?1; interval between and number of boluses required were 4 (1–8) minutes and 6 (4–11) boluses respectively. Total dose of propofol was 19 (12.3–37.1) mg kg?1. Awakening between boluses was very abrupt. In group CRI, propofol infusion rate was 0.85 (0.8–0.9) mg kg?1 minute?1, and anaesthesia was stable. Body temperature, heart and respiratory rates, oxygen saturation (by pulse oximeter) and reflexes did not differ between groups. Oxygen saturations (from pulse oximeter readings) were low in some birds. Following anaesthesia, all birds recovered within 40 minutes. In 55 % of all, transient signs of central nervous system excitement occurred during recovery.Conclusions and clinical relevance8 mg kg?1 propofol appears an adequate induction dose for mute swans. For maintenance, a CRI of 0.85 mg kg?1 minute?1 produced stable anaesthesia suitable for painless clinical procedures. In contrast bolus administration, was unsatisfactory as birds awoke very suddenly, and the short intervals between bolus requirements hampered clinical procedures. Administration of additional oxygen throughout anaesthesia might reduce the incidence of low arterial haemoglobin saturation.  相似文献   

6.
ObjectiveTo evaluate the effects of propofol, on isoflurane minimum alveolar concentration (MAC) and cardiovascular function in mechanically ventilated goats.Study designProspective, randomized, crossover experimental study.AnimalsSix goats, three does and three wethers.MethodsGeneral anaesthesia was induced with isoflurane in oxygen. Following endotracheal intubation, anaesthesia was maintained with isoflurane in oxygen. Intermittent positive pressure ventilation was applied. Baseline isoflurane MAC was determined, the noxious stimulus used being clamping a claw. The goats then received, on separate occasions, three propofol treatments intravenously: bolus of 0.5 mg kg?1 followed by a constant rate infusion (CRI) of 0.05 mg kg?1 minute?1 (treatment LPROP); bolus of 1.0 mg kg?1 followed by a CRI of 0.1 mg kg?1 minute?1 (treatment MPROP), bolus of 2.0 mg kg?1 followed by a CRI of 0.2 mg kg?1 minute?1 (treatment HPROP). Isoflurane MAC was re-determined following propofol treatments. Plasma propofol concentrations at the time of MAC confirmation were measured. Cardiopulmonary parameters were monitored throughout the anaesthetic period. Quality of recovery was scored. The Friedman test was used to test for differences between isoflurane MACs. Medians of repeatedly measured cardiovascular parameters were tested for differences between and within treatments using repeated anova by ranks (p < 0.05 for statistical significance).ResultsIsoflurane MAC [median (interquartile range)] was 1.37 (1.36–1.37) vol%. Propofol CRI significantly reduced the isoflurane MAC, to 1.15 (1.08–1.15), 0.90 (0.87–0.93) and 0.55 (0.49–0.58) vol% following LPROP, MPROP and HPROP treatment, respectively. Increasing plasma propofol concentrations strongly correlated (Spearman rank correlation) with decrease in MAC (Rho = 0.91). Cardiovascular function was not affected significantly by propofol treatment. Quality of recovery was satisfactory.Conclusions and clinical relevanceIn goats, propofol reduces isoflurane MAC in a dose-dependent manner with minimal cardiovascular effects.  相似文献   

7.
ObjectiveTo report the cardiovascular variables, anaesthetic effects and recovery quality of an anaesthesia technique using variable rate infusion propofol combined with constant rate infusion fentanyl in dogs undergoing elective surgery.Study designProspective clinical trial.AnimalsA total of 27 dogs, aged 2.7 ± 2.65 years and weighing 24 ± 11 kg.MethodsFollowing intramuscular acepromazine (0.03 or 0.05 mg kg?1) and subcutaneous carprofen (4 mg kg?1) pre-medication, anaesthesia was induced with propofol (4.0 ± 0.5 mg kg?1) intravenously (IV). All dogs were ventilated with 100% oxygen to maintain normocapnia. Propofol was infused at 0.4 mg kg?1 minute?1 for 20 minutes and then at 0.3 mg kg?1minute?1. If mean arterial blood pressure (MAP) decreased below 70 mmHg, propofol infusion was reduced by 0.1 mg kg?1 minute?1. Five minutes after induction of anaesthesia, fentanyl was administered (2 μg kg?1) IV followed by the infusion at 0.5 μg kg?1 minute?1 and atropine (40 μg kg?1) IV. Heart rate, MAP, respiratory rate, tidal volume, end-tidal carbon dioxide, presence of reflexes, movements and recovery times and quality were recorded.ResultsMean anaesthetic duration was 131 ± 38.5 minutes. Mean heart rate peaked 10 minutes after atropine injection and gradually declined, reaching pre-anaesthetic values at 55 minutes. MAP easily was maintained above 70 mmHg. Mean times to return of spontaneous ventilation, extubation, head lift and sternal recumbency were 21 ± 10.1, 33 ± 14.6, 43 ± 19.7 and 65 ± 23.4 minutes, respectively. Recovery was smooth and quiet. The time to sternal recumbency was significantly correlated with the duration of anaesthesia and total dose of propofol; time to extubation was correlated to total dose of propofol.Conclusion and clinical relevancePropofol and fentanyl infusions provided stable cardiovascular function and satisfactory conditions for surgery. Some modifications of infusion rates are required to improve the long-recovery times.  相似文献   

8.
ObjectiveTo compare cardiopulmonary function, recovery quality, and total dosages required for induction and 60 minutes of total intravenous anesthesia (TIVA) with propofol (P) or a 1:1 mg mL−1 combination of propofol and ketamine (KP).Study designRandomized crossover study.AnimalsTen female Beagles weighing 9.4 ± 1.8 kg.MethodsDogs were randomized for administration of P or KP in a 1:1 mg mL−1 ratio for induction and maintenance of TIVA. Baseline temperature, pulse, respiratory rate (fR), noninvasive mean blood pressure (MAP), and hemoglobin oxygen saturation (SpO2) were recorded. Dogs were intubated and spontaneously breathed room air. Heart rate (HR), fR, MAP, SpO2, end tidal carbon dioxide tension (Pe’CO2), temperature, and salivation score were recorded every 5 minutes. Arterial blood gas analysis was performed at 10, 30, and 60 minutes, and after recovery. At 60 minutes the infusion was discontinued and total drug administered, time to extubation, and recovery score were recorded. The other treatment was performed 1 week later.ResultsKP required significantly less propofol for induction (4.0 ± 1.0 mg kg−1 KP versus 5.3 ±1.1 mg kg−1 P, p = 0.0285) and maintenance (0.3 ± 0.1 mg kg−1 minute−1 KP versus 0.6 ±0.1 mg kg−1 minute−1 P, p = 0.0018). Significantly higher HR occurred with KP. Both P and KP caused significantly lower MAP compared to baseline. MAP was significantly higher with KP at several time points. P had minimal effects on respiratory variables, while KP resulted in significant respiratory depression. There were no significant differences in salivation scores, time to extubation, or recovery scores.Conclusions and clinical relevanceTotal intravenous anesthesia in healthy dogs with ketamine and propofol in a 1:1 mg mL−1 combination resulted in significant propofol dose reduction, higher HR, improved MAP, no difference in recovery quality, but more significant respiratory depression compared to propofol alone.  相似文献   

9.
ObjectivesTo evaluate the cardiorespiratory and biochemical effects of ketamine-propofol (KP) or guaifenesin-ketamine-xylazine (GKX) anesthesia in donkeys.Study designProspective crossover trial.AnimalsEight healthy, standard donkeys, aged 10 ± 5 years and weighing 153 ± 23 kg.MethodsDonkeys were premedicated with 1.0 mg kg?1 of xylazine (IV) in both treatments. Eight donkeys were administered ketamine (1.5 mg kg?1) and propofol (0.5 mg kg?1) for induction, and anesthesia was maintained by constant rate infusion (CRI) of ketamine (0.05 mg kg?1 minute?1) and propofol (0.15 mg kg?1 minute?1) in the KP treatment. After 10 days, diazepam (0.05 mg kg?1) and ketamine (2.2 mg kg?1) were administered for induction, and anesthesia was maintained by a CRI (2.0 mL kg?1 hour?1) of ketamine (2.0 mg mL?1), xylazine (0.5 mg mL?1) and guaifenesin (50 mg mL?1) solution. Quality of anesthesia was assessed along with cardiorespiratory and biochemical measurements.ResultsAnesthetic induction took longer in GKX than in KP. The induction was considered good in 7/8 with KP and in 6/8 in GKX. Anesthetic recovery was classified as good in 7/8 animals in both treatments. Xylazine administration decreased heart rate (HR) in both treatments, but in KP the HR increased and was higher than GKX throughout the anesthetic period. Respiratory rate was higher in GKX than in KP. PaO2 decreased significantly in both groups during the anesthetic period. Glucose concentrations [GLU] increased and rectal temperature and PCV decreased in both treatments. Arterial lactate [LAC] increased at recovery compared with all time points in KP. [GLU] and calcium were higher in GKX than in KP at recovery.Conclusion and clinical relevanceThese protocols induced significant hypoxemia but no other cardiorespiratory or metabolic changes. These protocols could be used to maintain anesthesia in donkeys, however, they were not tested in animals undergoing surgery.  相似文献   

10.
ObjectiveTo determine the effect of intravenous ketamine on the minimum alveolar concentration of sevoflurane needed to block autonomic response (MACBAR) to a noxious stimulus in dogs.Study designRandomized, crossover, prospective design.AnimalsEight, healthy, adult male, mixed-breed dogs, weighing 11.2–16.1 kg.MethodsDogs were anesthetized with sevoflurane on two occasions, 1 week apart, and baseline MACBAR (B-MACBAR) was determined on each occasion. MACBAR was defined as the mean of the end-tidal sevoflurane concentrations that prevented and allowed an increase (≥15%) in heart rate or invasive mean arterial pressure in response to a noxious electrical stimulus (50 V, 50 Hz, 10 ms). Dogs then randomly received either a low-dose (LDS) or high-dose series (HDS) of ketamine, and treatment MACBAR (T-MACBAR) was determined. The LDS had an initial loading dose (LD) of 0.5 mg kg?1 and constant rate infusion (CRI) at 6.25 μg kg?1 minute?1, followed, after T-MACBAR determination, by a second LD (1 mg kg?1) and CRI (12.5 μg kg?1 minute?1). The HDS had an initial LD (2 mg kg?1) and CRI (25 μg kg?1 minute?1) followed by a second LD (3 mg kg?1) and CRI (50 μg kg?1 minute?1). Data were analyzed with a mixed-model anova and are presented as LSM ± SEM.ResultsThe B-MACBAR was not significantly different between treatments. Ketamine at 12.5, 25, and 50 μg kg?1 minute?1 decreased sevoflurane MACBAR, and the maximal decrease (22%) occurred at 12.5 μg kg?1 minute?1. The percentage change in MACBAR was not correlated with either the log plasma ketamine or norketamine concentration.Conclusions and clinical relevanceKetamine at clinically relevant doses of 12.5, 25, and 50 μg kg?1 minute?1 decreased sevoflurane MACBAR, although the reduction was neither dose-dependent nor linear.  相似文献   

11.
ObjectiveTo determine the possible additive effect of midazolam, a GABAA agonist, on the end-tidal concentration of isoflurane that prevents movement (MACNM) in response to noxious stimulation.Study designRandomized cross-over experimental study.AnimalsSix healthy, adult intact male, mixed-breed dogs.MethodsAfter baseline isoflurane MACNM (MACNM-B) determination, midazolam was administered as a low (LDS), medium (MDS) or high (HDS) dose series of midazolam. Each series consisted of two dose levels, low and high. The LDS was a loading dose (Ld) of 0.2 mg kg?1 and constant rate infusion (CRI) (2.5 μg kg?1 minute?1) (LDL), followed by an Ld (0.4 mg kg?1) and CRI (5 μg kg?1 minute?1) (LDH). The MDS was an Ld (0.8 mg kg?1) and CRI (10 μg kg?1 minute?1) (MDL) followed by an Ld (1.6 mg kg?1) and CRI (20 μg kg?1 minute?1) (MDH). The HDS was an Ld (3.2 mg kg?1) and CRI (40 μg kg?1 minute?1) (HDL) followed by an Ld (6.4 mg kg?1) and CRI (80 μg kg?1 minute?1) (HDH). MACNM was re-determined after each dose in each series (MACNM-T).ResultsThe median MACNM-B was 1.42. MACNM-B did not differ among groups (p >0.05). Percentage reduction in MACNM was significantly less in the LDS (11 ± 5%) compared with MDS (30 ± 5%) and HDS (32 ± 5%). There was a weak correlation between the plasma midazolam concentration and percentage MACNM reduction (r = 0.36).Conclusion and clinical relevanceMidazolam doses in the range of 10–80 μg kg?1 minute?1 significantly reduced the isoflurane MACNM. However, doses greater than 10 μg kg?1 minute?1 did not further decrease MACNM indicating a ceiling effect.  相似文献   

12.
ObjectiveTo investigate the effect of plasma concentrations obtained by a low dose constant rate infusion (CRI) of racemic ketamine or S-ketamine on the nociceptive withdrawal reflex (NWR) in standing ponies.Study designProspective, blinded, cross-over study.AnimalsSix healthy 5-year-old Shetland ponies.MethodsPonies received either 0.6 mg kg−1 racemic ketamine (group RS) or 0.3 mg kg−1 S-ketamine (group S) intravenously (IV), followed by a CRI of 20 μg kg−1minute−1 racemic ketamine (group RS) or 10 μg kg−1minute−1 S-ketamine (group S) for 59 minutes. The NWR was evoked by transcutaneous electrical stimulation of a peripheral nerve before drug administration, 15 and 45 minutes after the start of the bolus injection and 15 minutes after the end of the CRI. Electromyographic responses were recorded and analysed. Arterial blood was collected before stimulation and plasma concentrations of ketamine and norketamine were measured enantioselectively using capillary electrophoresis. Ponies were video recorded and monitored to assess drug effects on behaviour, heart rate (HR), mean arterial blood pressure (MAP) and respiratory rate.ResultsThe NWR was significantly depressed in group RS at plasma concentrations between 20 and 25 ng mL−1 of each enantiomer. In group S, no significant NWR depression could be observed; plasma concentrations of S-ketamine (9–15 ng mL−1) were lower, compared to S-ketamine concentrations in group RS, although this difference was not statistically significant. Minor changes in behaviour, HR and MAP only occurred within the first 5–10 minutes after bolus drug administration in both groups.ConclusionAntinociceptive activity in standing ponies, demonstrated as a depression of the NWR, could only be detected after treatment with racemic ketamine. S-ketamine may have lacked this effect as a result of lower plasma concentrations, a more rapid metabolism or a lower potency of S-ketamine in Equidae so further investigation is necessary.  相似文献   

13.
Continuous infusion of propofol in dogs premedicated with methotrimeprazine   总被引：1，自引：0，他引：1  
Objective To evaluate the cardiopulmonary and clinical effects of three different infusion rates of propofol in dogs premedicated with methotrimeprazine. Study design Randomized experimental trial. Animals Ten healthy adult mixed‐breed male and female dogs, weighing from 14 to 20 kg. Methods Dogs were premedicated with methotrimeprazine [1 mg kg?1 intravenously (IV)] followed by induction of anesthesia with 4.5 mg kg?1 of propofol IV and maintenance with propofol for 60 minutes as follows: T1, 0.2 mg kg?1 minute?1; T2, 0.3 mg kg?1minute?1; and T3, 0.4 mg kg?1minute?1. Heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), end‐tidal CO2 (PETCO2), arterial hemoglobin O2 saturation, arterial blood gases, and pedal and cutaneous reflexes were measured before and 5, 10, 20, 30, 45 and 60 minutes after the beginning of the propofol infusion. Statistical analysis was performed using an anova . Results Heart rate increased during anesthesia in all cases and arterial blood pressure decreased only in dogs in the T3 category. Respiratory depression was proportional to the infusion rate of propofol. Muscle relaxation was satisfactory, but analgesia was inadequate in the three treatments. Conclusions The infusion of 0.2–0.4 mg kg?1 minute?1 of propofol produced a dose‐dependent respiratory depression. The presence of a pedal withdrawal reflex and marked cardiovascular responses to this noxious stimulus suggests that anesthesia may not be of sufficient depth for surgery to be carried out. Clinical relevance Although several studies have been performed using propofol in animals, few studies have investigated the cardiopulmonary and analgesic effects with different doses. The determination of an adequate propofol infusion rate is necessary for the routine use of this intravenous anesthetic for the maintenance of anesthesia during major surgical procedures in dogs.  相似文献   

14.
ObjectiveTo compare a propofol continuous rate infusion (CRI) with a target-controlled infusion (TCI) in dogs.Study designRandomized prospective double-blinded clinical study.AnimalsA total of 38 healthy client-owned dogs.MethodsDogs premedicated intramuscularly with acepromazine (0.03 mg kg–1) and an opioid (pethidine 3 mg kg–1, morphine 0.2 mg kg–1 or methadone 0.2 mg kg–1) were allocated to P-CRI group (propofol 4 mg kg–1 intravenously followed by CRI at 0.2 mg kg–1 minute–1), or P-TCI group [propofol predicted plasma concentration (Cp) of 3.5 μg mL–1 for induction and maintenance of anaesthesia via TCI]. Plane of anaesthesia, heart rate, respiratory rate, invasive blood pressure, oxygen haemoglobin saturation, end-tidal carbon dioxide and body temperature were monitored by an anaesthetist blinded to the group. Numerical data were analysed by unpaired t test or Mann–Whitney U test, one-way analysis of variance and Dunnett’s post hoc test. Categorical data were analysed with Fisher’s exact test. Significance was set for p < 0.005.ResultsOverall, propofol induced a significant incidence of relative hypotension (mean arterial pressure 20% below baseline, 45%), apnoea (71%) and haemoglobin desaturation (65%) at induction of anaesthesia, with a higher incidence of hypotension and apnoea in the P-CRI than P-TCI group (68% versus 21%, p = 0.008; 84% versus 58%, p = 0.0151, respectively). Propofol Cp was significantly higher at intubation in the P-CRI than P-TCI group (4.83 versus 3.5 μg mL–1, p < 0.0001), but decreased during infusion, while Cp remained steady in the P-TCI group. Total propofol administered was similar between groups.Conclusions and clinical relevanceBoth techniques provided a smooth induction of anaesthesia but caused a high incidence of side effects. Titration of anaesthesia with TCI caused fewer fluctuations in Cp and lower risk of hypotension compared with CRI.  相似文献   

15.
ObjectiveTo compare the effects of propofol and alfaxalone on respiration in cats.Study designRandomized, ‘blinded’, prospective clinical trial.AnimalsTwenty cats undergoing ovariohysterectomy.MethodsAfter premedication with medetomidine 0.01 mg kg−1 intramuscularly and meloxicam 0.3 mg kg−1 subcutaneously, the cats were assigned randomly into two groups: group A (n = 10) were administered alfaxalone 5 mg kg−1 minute−1 followed by 10 mg kg−1 hour−1 intravenously (IV) and group P (n = 10) were administered propofol 6 mg kg−1 minute−1 followed by 12 mg kg−1hour−1 IV for induction and maintenance of anaesthesia, respectively. After endotracheal intubation, the tube was connected to a non-rebreathing system delivering 100% oxygen. The anaesthetic maintenance drug rate was adjusted (± 0.5 mg kg−1 hour−1) every 5 minutes according to a scoring sheet based on physiologic variables and clinical signs. If apnoea > 30 seconds, end-tidal carbon dioxide (Pe′CO2) > 7.3 kPa (55 mmHg) or arterial haemoglobin oxygen saturation (SpO2) < 90% occurred, manual ventilation was provided. Methadone was administered postoperatively. Data were analyzed using independent-samples t-tests, Fisher's exact test, linear mixed-effects models and binomial test.ResultsManual ventilation was required in two and eight of the cats in group A and P, respectively (p = 0.02). Two cats in both groups showed apnoea. Pe′CO2 > 7.3 kPa was recorded in zero versus four and SpO2 < 90% in zero versus six cats in groups A and P respectively. Induction and maintenance dose rates (mean ± SD) were 11.6 ± 0.3 mg kg−1 and 10.7 ± 0.8 mg kg−1 hour−1 for alfaxalone and 11.7 ± 2.7 mg kg−1 and 12.4 ± 0.5 mg kg−1 hour−1 for propofol.Conclusion and clinical relevanceAlfaxalone had less adverse influence on respiration than propofol in cats premedicated with medetomidine. Alfaxalone might be better than propofol for induction and maintenance of anaesthesia when artificial ventilation cannot be provided.  相似文献   

16.
ObjectiveTo compare, in horses undergoing laparotomy for colic, the effects of administering or not administering a loading intravenous (IV) bolus of lidocaine prior to its constant rate infusion (CRI). Effects investigated during isoflurane anaesthesia were end-tidal isoflurane concentration (Fe’ISO), cardiovascular function, anaesthetic stability and the quality of recovery.Study designProspective, randomized clinical study.AnimalsThirty-six client-owned horses.MethodsHorses were assigned randomly to receive lidocaine as a CRI (50 μg kg−1 minute−1) either preceded (LB) or not preceded (L) by a loading dose (1.5 mg kg−1 IV over 15 minutes). Lidocaine infusion (LInf) was started (T0) within 20 minutes after induction of general anaesthesia and discontinued approximately 30 minutes before the end of surgery. Anaesthetic depth, Fe’ISO, intra-operative physiological parameters and quality of recovery were assessed or measured. Data were analysed using one-way anova, t-test, Fisher test, Wilcoxon and Kruskal–Wallis tests as appropriate (p < 0.05).ResultsMean ± SD Fe’ISO was 1.21 ± 0.08% in group LB and 1.23 ± 0.06% in group L. Heart rate was significantly higher in group L than in group LB at times T5-T15, T25, T35 and T95. No difference was found between groups in other measured physiological values, nor in any measure taken to improve these parameters. Recovery phase was comparable and satisfactory in all but one full term pregnant horse in group L which fractured a femur during recovery.ConclusionPreloading with a lidocaine bolus prior to a CRI of lidocaine did not influence isoflurane requirements, cardiopulmonary effects (other than a reduction in heart rate at some time points) or recovery compared to no preloading bolus.Clinical relevanceA loading dose of lidocaine prior to CRI does not confer any advantage in horses undergoing laparotomy for colic.  相似文献   

17.
ObjectiveTo investigate the cardiorespiratory, nociceptive and endocrine effects of the combination of propofol and remifentanil, in dogs sedated with acepromazine.Study designProspective randomized, blinded, cross-over experimental trial.AnimalsTwelve healthy adult female cross-breed dogs, mean weight 18.4 ± 2.3 kg.MethodsDogs were sedated with intravenous (IV) acepromazine (0.05 mg kg?1) followed by induction of anesthesia with IV propofol (5 mg kg?1). Anesthesia was maintained with IV propofol (0.2 mg kg?1 minute?1) and remifentanil, infused as follows: R1, 0.125 μg kg?1 minute?1; R2, 0.25 μg kg?1 minute?1; and R3, 0.5 μg kg?1 minute?1. The same dogs were administered each dose of remifentanil at 1-week intervals. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (fR), end tidal CO2 (Pe′CO2), arterial hemoglobin O2 saturation, blood gases, and rectal temperature were measured before induction, and 5, 15, 30, 45, 60, 75, 90, and 120 minutes after beginning the infusion. Nociceptive response was investigated by electrical stimulus (50 V, 5 Hz and 10 ms). Blood samples were collected for plasma cortisol measurements. Statistical analysis was performed by anova (p < 0.05).ResultsIn all treatments, HR decreased during anesthesia with increasing doses of remifentanil, and increased significantly immediately after the end of infusion. MAP remained stable during anesthesia (72–98 mmHg). Antinociception was proportional to the remifentanil infusion dose, and was considered satisfactory only with R2 and R3. Plasma cortisol concentration decreased during anesthesia in all treatments. Recovery was smooth and fast in all dogs.Conclusions and clinical relevanceInfusion of 0.25–0.5 μg kg?1 minute?1 remifentanil combined with 0.2 mg kg?1 minute?1 propofol produced little effect on arterial blood pressure and led to a good recovery. The analgesia produced was sufficient to control the nociceptive response applied by electrical stimulation, suggesting that it may be appropriate for performing surgery.  相似文献   

18.
ObjectiveTo evaluate total intravenous anesthesia with propofol alone or in combination with S(+)-ketamine in rabbits undergoing surgery.Study designProspective, randomized, blinded trial.AnimalsNine 6-month-old New Zealand white rabbits, weighing 2.5–3 kg.MethodsAnimals received acepromazine (0.1 mg kg?1) and buprenorphine (20 μg kg?1) IM, and anesthesia was induced with propofol (2 mg kg?1) and S(+)-ketamine (1 mg kg?1) IV. Rabbits received two of three treatments: propofol (0.8 mg kg?1 minute?1) (control treatment, P), propofol (0.8 mg kg?1 minute?1) + S(+)-ketamine (100 μg kg?1 minute?1) (PK100) or propofol (0.8 mg kg?1 minute?1) + S(+)-ketamine (200 μg kg?1 minute?1) (PK200). All animals received 100% O2 during anesthesia. Heart rate, mean arterial pressure, hemoglobin oxygen saturation and respiratory rate were measured every 5 minutes for 60 minutes. Blood-gas parameters were measured at zero time and 60 minutes. Additional propofol injections, if necessary, and recovery time were recorded.ResultsAn increase in heart rate was observed in P and PK200 up to 10 minutes after induction of anesthesia. Blood pressure decreased from baseline values during the first 10 minutes in P and PK200, and during the first 15 minutes and between 45 and 55 minutes in PK100. A reduction in respiratory rate was observed after 5 minutes in all treatments. Respiratory acidosis was observed in all treatments. Six (2.8) [median (interquartile range)] further propofol injections were necessary in P, which differed statistically from PK100 [1 (0.2)] and PK200 [2 (0.6)]. Recovery time was shorter in P compared with PK100 and PK200, being [7.5 minutes (4.11)], [17.5 minutes (10.30)], and [12 minutes (10.30)], respectively.Conclusions and clinical relevanceS(+)-ketamine potentiates propofol-induced anesthesia in rabbits, providing better maintenance of heart rate. All of these techniques were accompanied by clinically significant respiratory depression.  相似文献   

19.
ObjectiveTo describe the hypnotic effects of a single bolus dose of propofol in Japanese macaques, and to develop a pharmacokinetic model.Study designProspective experimental trial.AnimalsFour male macaques (5-6 years old, 8.0-11.2 kg).MethodsThe macaque was restrained and 8 mg kg?1 of propofol was administrated intravenously at 6 mg kg?1 minute?1. Behavioural changes without stimuli (first experiment) then responses to external stimuli (the second experiment) were assessed every 2 minutes for 20 minutes. Venous blood samples were collected before and at 1, 5, 15, 30, 60, 120 and 210 minutes after drug administration, and plasma concentrations of propofol were measured (third experiment). Pharmacokinetic modelling was performed using NONMEM VI.ResultsMacaques were recumbent without voluntary movement for a mean 14.0 ± 2.7 SD (range 10.5-16.2) or 10.0 ± 3.4 (7.2-14.5) minutes and recovered to behave as pre-administration by 25.1 ± 3.6 (22.1-30.1) or 22.2 ± 1.5 (21.1-24.3) minutes after the end of propofol administration without or with stimuli, respectively. Respiratory and heart rates were stable throughout the experiments (28-68 breaths minute?1 and 72-144 beats minute?1, respectively). Our final pharmacokinetic model included three compartments and well described the plasma concentration of propofol. The population pharmacokinetic parameters were: V1 = 10.4 L, V2=8.38 L, V3=72.7 L, CL1= 0.442 L minute?1, CL2= 1.14 L minute?1, CL3= 0.313 L minute?1, (the volumes of distribution and the clearances for the central, rapid and slow peripheral compartments, respectively).ConclusionsIntravenous administration of propofol (8 mg kg?1) at 6 mg kg?1 minute?1 to Japanese macaques had a hypnotic effect lasting more than 7 minutes. A three-compartment model described propofol plasma concentrations over more than 3 hours.Clinical relevanceThe developed pharmacokinetic parameters may enable simulations of administration protocols to maintain adequate plasma concentration of propofol.  相似文献   

20.
ObjectiveTo compare the propofol infusion rate and cardiopulmonary effects during total intravenous anesthesia with propofol alone and propofol combined with methadone, fentanyl or nalbuphine in domestic chickens undergoing ulna osteotomy.Study designProspective, randomized, experiment trial.AnimalsA total of 59 healthy Hissex Brown chickens weighing 1.5 ± 0.2 kg.MethodsAnesthesia was induced with propofol (9 mg kg–1) administered intravenously (IV) and maintained with propofol (1.2 mg kg–1 minute–1) for 30 minutes. Birds were intubated and supplemented with 100% oxygen through a nonrebreathing circuit under spontaneous ventilation. Thereafter, each animal was randomly assigned to one of four groups: group P, no treatment; group PM, methadone (6 mg kg–1) intramuscularly (IM); group PN, nalbuphine IM (12.5 mg kg–1); and group PF, fentanyl IV (30 μg kg–1 loading dose, 30 μg kg–1 hour–1 constant rate infusion). During the osteotomy surgery, the propofol infusion rate was adjusted to avoid movement of birds and provide adequate anesthesia. Pulse rate, invasive blood pressure, respiratory frequency, end-tidal carbon dioxide partial pressure (Pe′CO2) and hemoglobin oxygen saturation (SpO2) were recorded.ResultsData were available from 58 chickens. The mean ± standard deviation propofol infusion rate (mg kg–1 minute–1) for the duration of anesthesia was: group P, 0.81 ± 0.15; group PM, 0.66 ± 0.11; group PN, 0.60 ± 0.14; and group PF, 0.80 ± 0.07. Significant differences were P versus PM (p = 0.042), P versus PN (p = 0.002) and PF versus PN (p = 0.004). Pulse rate, blood pressure and SpO2 remained acceptable for anesthetized birds with minor differences among groups. Values of Pe′CO2 >60 mmHg (8 kPa) were observed in all groups.Conclusions and clinical relevanceMethadone and nalbuphine, but not fentanyl, decreased the propofol infusion rate required for anesthesia maintenance, but resulted in no obvious benefit in physiological variables.  相似文献   

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