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1.
ObjectiveTo measure the pressure profile during caudal extradural puncture and subsequent extradural anaesthesia in cattle and to investigate the presence of extradural pressure waves.Study designProspective experimental study.AnimalsEleven cattle aged 4.1 ± 2.5 years (range 0.8 to 8.8 years), with a body weight of 613 ± 162 kg (range 302–840 kg).MethodsCaudal extradural puncture was performed. To measure the extradural pressure profile, the needle was connected to an electronic pressure transducer placed at the height of the base of the tail. The pressure profile was recorded for 3 minutes following extradural puncture. Lack of resistance to injection of saline was assessed. One minute and 10 minutes after extradural anaesthesia with procaine extradural pressure was recorded. Correct extradural needle placement was assessed by clinical response.ResultsThree minutes after extradural puncture the median pressure was ?16 (range ?25 to 25) mmHg. Pressure in the extradural space 1 minute after the lack of resistance, 3 seconds after injection, and 10 minutes after injection was ?15 (?24 to 33) mmHg, 8 (?17 to 84) mmHg, and ?7 (?25 to 27) mmHg respectively. Pressure waves were visible after puncture, after lack of resistance, 3 seconds and 10 minutes after injection, in 4, 6, 8 and 7 cattle respectively. Pressure after testing lack of resistance, after the injection of local anaesthetic, as well as at the end of the measurement, period was significantly higher than baseline. All cattle showed clinical signs indicative of successful extradural needle placement.Conclusion and clinical relevance Extradural pressure was sub-atmospheric in 82% of the animals. Pressure waves were not consistently present before or after extradural injection, which limits their usefulness to confirm correct extradural needle placement. Extradural pressures increase significantly after injection of local anaesthetic solution. However, the clinical significance of the increase in extradural pressures was not clear.  相似文献   

2.
The objectives of this study were to measure the pressure in the caudal extradural space of standing horses and to evaluate the usefulness of pressure waves to identify correct needle placement. Caudal extradural pressure was measured in 12 healthy horses. The pressure and any extradural pressure waves were recorded for 3min after puncture, for 1min after testing for lack of resistance (LOR), and for 10min after lidocaine injection. Successful extradural drug administration was confirmed in all horses. The median extradural pressure findings after puncture, after LOR, immediately after injection and 10min after needle placement were -1.60kPa (range -2.27 to 1.33kPa), -0.67kPa (-2.27 to 5.73kPa), 5.00kPa (0.93 to 9.87kPa) and 0.13kPa (-0.67 to 4.53kPa), respectively. Extradural pressure waves were not always present. Extradural space pressure was sub-atmospheric in most horses and extradural injection significantly increased this pressure for up to 10min. Extradural pressure waves had limited usefulness in the confirmation of the correct placement of the needle.  相似文献   

3.
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4.
Objective To compare the effects of intravenous (IV) and extradural (ED) methadone on end‐tidal isoflurane concentration (Fe ′ISO) and postoperative analgesic requirements in dogs undergoing femoro‐tibial joint surgery. Study Design Randomized, blinded, clinical study. Animals Twenty‐four healthy client‐owned dogs undergoing surgical repair of ruptured cruciate ligaments. Methods Dogs were randomly assigned to two groups of 12 animals and received either ED or IV methadone (0.3 mg kg?1 diluted with saline to 0.2 mL kg?1). Pre‐anaesthetic medication was IV acepromazine (0.05 mg kg?1). Anaesthesia was induced with propofol and maintained initially with an Fe ′ISO of 1.0% delivered in oxygen. Methadone was injected with the dogs in sternal recumbency; the observer was unaware of the administration route. At 10 minutes (stimulation 1) and 20 minutes (stimulation 2) after methadone administration pelvic limb reflexes were tested by digit‐clamping. The time at skin incision (stimulation 3), joint‐capsule incision (stimulation 4), tibial tuberosity drilling (stimulation 5), fabellar suturing (stimulation 6) and extracapsular tightening (stimulation 7) were noted. Changes in heart rate (HR) and respiratory rate and arterial blood pressure associated with surgery were recorded along with the corresponding Fe ′ISO. After 20 minutes of anaesthesia, Fe ′ISO was decreased to the minimum required to maintain stable anaesthesia. Immediately after tracheal extubation, 1, 2, 3 and 6 hours postoperatively and on the morning after surgery, the degree of pain present was assessed using a numerical rating scale. The HR, respiratory rates and blood pressure were also recorded at these times. Serum cortisol and blood glucose concentrations were measured before pre‐anaesthetic medication and at each postoperative pain scoring interval except at 1 and 2 hours. Ketoprofen (2 mg kg?1), carprofen (4 mg kg?1) or meloxicam (0.2 mg kg?1) were given by subcutaneous injection whenever pain scoring indicated moderate discomfort was present. Results Controlled ventilation was required in six dogs which stopped breathing after IV methadone. The median Fe ′ISO at stimulus 5 was 1.0% in the IV and 0.83% in the ED group. At stimulus 6, Fe ′ISO was 1.0% in the IV and 0.8% in the ED group; the difference was statistically significant (p ≤ 0.05). There was no significant difference in the duration of postoperative analgesia associated with administration route. Conclusions Extradural methadone significantly reduces the isoflurane requirement compared with IV methadone during femoro‐tibial joint surgery in dogs. Clinical relevance Extradural methadone provides safe and effective pain relief in dogs undergoing cruciate ligament repair.  相似文献   

5.
ObjectiveTo investigate the influence of l–methadone on medetomidine–induced changes in arterial blood gases and clinical sedation in dogs.Study designProspective experimental cross–over study (Latin square design).AnimalsFive 1–year–old purpose bred laboratory beagle dogs of both sexes.MethodsEach dog was treated three times: medetomidine (20 μg kg?1 IV), l–methadone (0.1 mg kg?1 IV) and their combination. Arterial blood was collected for blood gas analysis. Heart and respiratory rates were recorded, and clinical sedation and reaction to a painful stimulus were scored before drug administration and at various time points for 30 minutes thereafter.ResultsArterial partial pressure of oxygen decreased slightly after medetomidine administration and further after medetomidine/l–methadone administration (range 55.2–86.7 mmHg, 7.4–11.6 kPa, at 5 minutes). A slight increase was detected in arterial partial pressure of carbon dioxide after administration of l–methadone and medetomidine/l–methadone (42.6 ± 2.9 and 44.7 ± 2.4 mmHg, 5.7 ± 0.4 and 6.0 ± 0.3 kPa, 30 minutes after drug administration, respectively). Arterial pH decreased slightly after administration of l–methadone and medetomidine/l–methadone. Heart and respiratory rates decreased after administration of medetomidine and medetomidine/l–methadone, and no differences were detected between the two treatments. Most dogs panted after administration of l–methadone and there was slight sedation. Medetomidine induced moderate or deep sedation, and all dogs were deeply sedated after administration of medetomidine/l–methadone. Reaction to a noxious stimulus was strong or moderate after administration of methadone, moderate or absent after administration of medetomidine, and absent after administration of medetomidine/l–methadone.Conclusions and clinical relevanceAt the doses used in this study, l–methadone potentiated the sedative and analgesic effects and the decrease in arterial oxygenation induced by medetomidine in dogs, which limits the clinical use of this combination.  相似文献   

6.
Objective To compare the anti‐nociceptive effects of extradural xylazine, fentanyl and a xylazine–fentanyl combination in sheep, and to measure the cardiopulmonary effects of the xylazine–fentanyl combination. Study design Prospective, randomized study. Animals Twenty‐five half‐merino ewes 2–4 years of age and body mass 54.2 ± 1.1 kg. Methods Six sheep in group 1 received 0.2 mg kg?1 xylazine by extradural injection, six in group 2 received fentanyl 1.5 µg kg?1 and 13 in group 3 received the combination of both treatments. In all groups, drugs were mixed with saline (0.15 mL kg?1 before injection). Pulmonary and carotid arterial catheters were placed in seven sheep of group 3 which were used to evaluate cardiopulmonary effects. Anti‐nociception was determined by the response to electrical stimulation (40 V for 1.5 milliseconds) of the left flank and by superficial and deep muscular ‘pinpricking’ stimulation of the pelvic and thoracic limbs and thoracolumbar region. Results Lack of response to electrical stimulation at the left flank was present in 10 ± 1.1 minutes (mean ± SEM) (group 1) and in 4.5 ± 0.5 minutes in group 3. The duration of lack of response to electrical stimulation at the left flank was 96 ± 6 minutes in group 1 and 315 ± 6 minutes in group 3. Responses persisted in group 3. Significant decreases (p < 0.05) in cardiac output 30, 45, 60 and 90 minutes after injection, and in cardiac work at 30 and 45 minutes were observed in the seven animals of group 3. Arterial blood pH was lowest at 90 minutes, arterial bicarbonate was lowest at 60 minutes and values for both arterial and mixed venous base excess increased significantly at 60 and 90 minutes. There was no significant change from baseline values in heart rate, mean arterial blood pressure, respiratory rate, body temperature, systemic vascular resistance, arterial and mixed venous PO2, PCO2, oxygen saturation, blood oxygen content, haemoglobin concentration, mixed venous blood bicarbonate and pH. Conclusions Fentanyl decreases the onset time and prolongs the duration of anti‐nociception produced by xylazine. The combination decreases cardiac output but is without significant respiratory effects. Clinical relevance Further studies are required to show that surgery is possible in sheep after extradural xylazine–fentanyl injection.  相似文献   

7.
ObjectiveTo evaluate and compare the effect of epidural bupivacaine on analgesia produced by epidural xylazine or medetomidine in buffaloes.Study designProspective, blinded study.AnimalsTen male buffalo calves (6-8 months of age; body weight 70-90 kg) were used on two occasions to conduct a total of 20 investigations.MethodsCaudal extradural analgesia was produced in four buffalo calves each by the injection of either xylazine (0.05 mg kg?1), medetomidine (15 μg kg?1) or 0.5% bupivacaine (0.125 mg kg?1), or combinations of xylazine and bupivacaine (0.05 and 0.125 mg kg?1), or medetomidine and bupivacaine (15 μg kg?1 and 0.125 mg kg?1) at the first intercoccygeal extradural space. Analgesia was tested using deep pinprick stimuli.ResultsExtradural administration of xylazine or medetomidine resulted in complete analgesia of the tail, perineum, inguinal region and the upper parts of the hind limbs, which was faster in onset and longer in duration in the medetomidine group than in the xylazine group. Addition of bupivacaine increased the intensity of the analgesia produced by xylazine, but not that produced by medetomidine. All the drugs caused mild to moderate ataxia, but signs of sedation were apparent only in animals which received xylazine or medetomidine. The extradural injections of all the drugs caused significant decrease in heart rate (p = 0.024), respiratory rate (p = 0.026) and rectal temperature (p = 0.036) from the respective baseline values, but the differences between the groups were not significant.ConclusionsMedetomidine produced a longer duration of analgesia than that produced by xylazine. Bupivacaine prolonged the analgesia produced by xylazine, but the analgesia produced by the combination of medetomidine and bupivacaine was not superior to that produced by medetomidine alone.Clinical relevanceBupivacaine may be used to prolong the extradural analgesia produced by xylazine, but not that produced by medetomidine in buffaloes.  相似文献   

8.
ObjectivesTo assess the accuracy of the ‘hanging drop method’ for identifying the extradural space in anaesthetized dogs positioned in sternal or lateral recumbency.Study designProspective randomized-experimental study.AnimalsSeventeen clinically healthy adult dogs, 10 females and seven males weighing 8.4–26.2 kg.MethodsDogs were positioned in either sternal (n = 8) or lateral (n = 9) recumbency under general anaesthesia. A 20 SWG spinal needle pre-filled with 0.9% saline was advanced through the skin into the lumbosacral extradural space and the response of the saline drop recorded, i.e. whether it: 1) was aspirated from the hub into the needle; 2) remained within the hub, or 3) moved synchronously with i) spontaneous respiration, ii) heart beat or iii) manual lung inflation. The position of the needle tip was ultimately determined by positive contrast radiography.ResultsOne dog positioned in lateral recumbency was excluded from the study because bleeding occurred from the needle hub. Saline was aspirated into the needle in seven of eight dogs held in sternal recumbency but in none of the dogs positioned in lateral recumbency. Accurate needle tip placement in the extradural space was confirmed by positive contrast radiography in all dogs.Conclusion and clinical relevanceThe ‘hanging drop’ method, when performed with a spinal needle, appears to be a useful technique for identifying the location of the extradural space in anaesthetized medium-sized dogs positioned in sternal, but not in lateral recumbency. The technique may yield ‘false negative’ results when performed in dogs positioned in sternal recumbency.  相似文献   

9.
BACKGROUND: Extradural lidocaine exerts several adverse effects which are seldom fatal. While cardiac arrest following extradural lidocaine injection has been reported in human beings, it has not hitherto been reported in dogs. OBSERVATIONS: The emergency management of a dog with complete urethral obstruction is described. We intended to perform vaginoscopy and cystostomy under extradural lidocaine anaesthesia, but cardiac asystole occurred a few minutes after injection. Resuscitation was successful. About 20 minutes later cardiac arrest recurred, and was treated successfully. The dog remained hypothermic for approximately 7 hours. Complete recovery without neurological deficit occurred the next day and the dog remained normal for at least 3 months. The probable cause of the problem was cranial lidocaine dispersion causing a drop in cardiac preload and cardiac arrest. The successful neurological outcome was attributed to early diagnosis and effective treatment. Hypothermia may have conferred cerebral protection during ischemia. CONCLUSIONS: Extradural local anaesthetic administration is not without risk and the technique should be tailored to individual animals. Constant monitoring is required to detect potentially fatal complications and increase the likelihood of successful outcome.  相似文献   

10.
ObjectiveTo compare the cardiovascular effects of four epidural treatments in isoflurane anaesthetised dogs.Study designProspective, randomized. experimental study.AnimalsSix female, neutered Beagle dogs (13.3 ± 1.0 kg), aged 3.6 ± 0.1 years.MethodsAnaesthesia was induced with propofol (8.3 ± 1.1 mg kg?1) and maintained with isoflurane in a mixture of oxygen and air [inspiratory fraction of oxygen (FiO2) = 40%], using intermittent positive pressure ventilation. Using a cross-over model, NaCl 0.9% (P); methadone 1% 0.1 mg kg?1 (M); ropivacaine 0.75% 1.65 mg kg?1 (R) or methadone 1% 0.1 mg kg?1 + ropivacaine 0.75% 1.65 mg kg?1 (RM) in equal volumes (0.23 mL kg?1) using NaCl 0.9%, was administered epidurally at the level of the lumbosacral space. Treatment P was administered to five dogs only. Cardiovascular and respiratory variables, blood gases, and oesophageal temperature were recorded at T-15 and for 60 minutes after epidural injection (T0).ResultsMean overall heart rate (HR in beats minute?1) was significantly lower after treatment M (119 ± 16) (p = 0.0019), R (110 ± 18) (p < 0.0001) and RM (109 ± 13) (p < 0.0001), compared to treatment P (135 ± 21). Additionally, a significant difference in HR between treatments RM and M was found (p = 0.04). After both ropivacaine treatments, systemic arterial pressures (sAP) were significantly lower compared to other treatments. No significant overall differences between treatments were present for central venous pressure, cardiac output, stroke volume, systemic vascular resistance, oxygen delivery and arterial oxygen content (CaO2). Heart rate and sAP significantly increased after treatment P and M compared to baseline (T-15). With all treatments significant reductions from baseline were observed in oesophageal temperature, packed cell volume and CaO2. A transient unilateral Horner’s syndrome occurred in one dog after treatment R.Conclusions and clinical relevanceClinically important low sAPs were observed after the ropivacaine epidural treatments in isoflurane anaesthetised dogs. Systemic arterial pressures were clinically acceptable when using epidural methadone.  相似文献   

11.
Objective – To describe general anesthesia and successful resuscitation of a dog developing asystole and apnea during extradural injection of local anesthetic and an opioid. Case Summary – A Beagle with a ruptured cranial cruciate was premedicated with acepromazine and methadone. Anesthesia was induced with propofol and, after endotracheal intubation, maintained using isoflurane in oxygen. During extradural injection of a mixture of lidocaine, bupivacaine, and morphine the dog developed apnea and asystole. Cardiopulmonary cerebral resuscitation was started promptly and the dog was successfully resuscitated. New Information Provided – Asystole and apnea are possible serious side effects of extradural anesthesia in dogs. With adequate monitoring and early detection successful resuscitation is possible.  相似文献   

12.
ObjectiveTo examine the influence of direct current shock application in anaesthetized horses with atrial fibrillation (AF) and to study the effects of cardioversion to sinus rhythm (SR).Study designProspective clinical study.AnimalsEight horses successfully treated for AF (transvenous electrical cardioversion after amiodarone pre-treatment).MethodsCardioversion catheters and a pacing catheter were placed under sedation [detomidine 10 μg kg?1 intravenously (IV)]. After additional sedation (5–10 μg kg?1 detomidine, 0.1 mg kg?1 methadone IV), anaesthesia was induced with ketamine, 2.2 mg kg?1 and midazolam, 0.06 mg kg?1 (IV) in a sling and maintained with isoflurane in oxygen. Flunixin meglumine, 1.1 mg kg?1, was administered IV. Shocks were delivered as biphasic truncated exponential waves, synchronized with the R-wave of the electrocardiogram. Monitoring included pulse oximetry, electrocardiography, capnography, inhalational anaesthetic agent concentration, arterial blood pressure, LiDCO and PulseCO cardiac index (CI) and arterial blood gases. Values before and after the first unsuccessful shock and before and after cardioversion to SR were compared.ResultsValues before the first shock were comparable to reported values in healthy, isoflurane anaesthetized horses. Reliable CI measurements could not be obtained using the PulseCO technique. Intermittent positive pressure ventilation was required in most horses (bradypnea and/or PaCO2 >8 kPa, 60 mmHg), while dobutamine was administered in two horses (0.3–0.5 μg kg?1 minute?1). After the 1st unsuccessful shock application, systolic arterial pressure (SAP) was decreased (p = 0.025), other recorded values were not influenced (CI measurements not available for this analysis). SR was associated with increases in CI (p = 0.039) and stroke index (p = 0.002) and a decrease in SAP (p = 0.030).Conclusions and clinical relevanceDespite the presence of AF, cardiovascular function was well maintained during anaesthesia and was not affected by shock application. Cardiac index and stroke index increased and SAP decreased after cardioversion.  相似文献   

13.
ObjectiveTo compare the efficacy of single-breath continuous positive airway pressure manoeuvre (CPAP-M) with inhaled salbutamol, and a combination of both.Study designRandomized, clinical study.AnimalsA total of 62 client-owned horses (American Society of Anesthesiologists status III–V) anaesthetized for laparotomy.MethodsHorses were premedicated with intravenous (IV) xylazine (0.4–0.6 mg kg–1), anaesthesia was induced with midazolam (0.06 mg kg–1 IV) and ketamine (2.2 mg kg–1 IV) and maintained with isoflurane in oxygen using volume-controlled ventilation without positive end-expiratory pressure. If PaO2 was < 100 mmHg (13.3 kPa), either a CPAP-M (50 cmH2O for 45 seconds) or salbutamol (0.002 mg kg–1) was administered. The intervention was considered successful if PaO2 reached 100 mmHg (13.3 kPa). If PaO2 remained < 100 mmHg (13.3 kPa), treatments were switched. PaO2/FiO2 ratio and estimated shunt fraction (F-shunt) were derived from data obtained from arterial blood gas measurements. Dynamic compliance (Cdyn) was calculated from variables recorded at the moment of arterial blood analysis. Fisher’s exact tests compared success rates between treatments, and linear models were performed to test whether the treatment modified the values of the measurements; p < 0.05.ResultsSalbutamol was the first intervention in 28 horses and was effective in 22 horses. CPAP-M was the first intervention in 34 horses and was effective in 26 horses. CPAP-M after salbutamol was performed in six horses, with four responders, and salbutamol after CPAP-M was administered to eight horses, with one responder. Salbutamol, but not CPAP-M, significantly decreased F-shunt. Both salbutamol and CPAP-M significantly increased Cdyn.Conclusions and clinical relevanceSalbutamol and CPAP-M were comparably effective in improving oxygenation and Cdyn in anaesthetized horses with PaO2 < 100 mmHg (13.3 kPa). Whether combining both treatments might be beneficial needs to be confirmed on a larger number of horses.  相似文献   

14.
ObjectiveTo investigate the cardiovascular effects of epidural romifidine in isoflurane-anaesthetized dogs.Study designProspective, randomized, blinded experiment.AnimalsA total of six healthy adult female Beagles aged 1.25 ± 0.08 years and weighing 12.46 ± 1.48 (10.25–14.50) kg.MethodsAnaesthesia was induced with propofol (6–9 mg kg?1) and maintained with 1.8–1.9% end-tidal isoflurane in oxygen. End-tidal CO2 was kept between 35 and 45 mmHg (4.7–6.0 kPa) using intermittent positive pressure ventilation. Heart rate (HR), arterial blood pressure and cardiac output (CO) were monitored. Cardiac output was determined using a LiDCO monitor and the derived parameters were calculated. After baseline measurements, either 10 μg kg?1 romifidine or saline (total volume 1 mL 4.5 kg?1) was injected into the lumbosacral epidural space. Data were recorded for 1 hour after epidural injection. A minimum of 1 week elapsed between treatments.ResultsAfter epidural injection, the overall means (± standard deviation, SD) of HR (95 ± 20 bpm), mean arterial blood pressure (MAP) (81 ± 19 mmHg), CO (1.63 ± 0.66 L minute?1), cardiac index (CI) (2.97 ± 1.1 L minute?1 m?2) and stroke volume index (SI) (1.38 ± 0.21 mL beat?1 kg?1) were significantly lower in the romifidine treatment compared with the overall means in the saline treatment [HR (129 ± 24 bpm), MAP (89 ± 17 mmHg), CO (3.35 ± 0.86 L minute?1), CI (6.17 ± 1.4 L minute?1 m?2) and SI (2.21 ± 0.21 mL beat?1 kg?1)]. The overall mean of systemic vascular resistance index (SVRI) (7202 ± 2656 dynes seconds cm?5 m?2) after epidural romifidine injection was significantly higher than the overall mean of SVRI (3315 ± 1167 dynes seconds cm?5 m?2) after epidural saline injection.ConclusionEpidural romifidine in isoflurane-anaesthetized dogs caused significant cardiovascular effects similar to those reportedly produced by systemic romifidine administration.Clinical relevanceSimilar cardiovascular monitoring is required after epidural and systemically administered romifidine. Further studies are required to evaluate the analgesic effects of epidural romifidine.  相似文献   

15.
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   

16.
ObjectiveTo determine the cardiopulmonary effects of etorphine and thiafentanil for immobilization of blesbok.Study designBlinded, randomized, two-way crossover study.AnimalsA group of eight adult female blesbok.MethodsAnimals were immobilized twice, once with etorphine (0.09 mg kg–1) and once with thiafentanil (0.09 mg kg–1) administered intramuscularly by dart. Immobilization quality was assessed and analysed by Wilcoxon signed-rank test. Time to final recumbency was compared between treatments by one-way analysis of variance. Cardiopulmonary effects including respiratory rate (?R), arterial blood pressures and arterial blood gases were measured. A linear mixed model was used to assess the effects of drug treatments over the 40 minute immobilization period. Significant differences between treatments, for treatment over time as well as effect of treatment by time on the variables, were analysed (p < 0.05).ResultsThere was no statistical difference (p = 0.186) between treatments for time to recumbency. The mean ?R was lower with etorphine (14 breaths minute–1) than with thiafentanil (19 breaths minute–1, p = 0.034). The overall mean PaCO2 was higher with etorphine [45 mmHg (6.0 kPa)] than with thiafentanil [41 mmHg (5.5 kPa), p = 0.025], whereas PaO2 was lower with etorphine [53 mmHg (7.1 kPa)] than with thiafentanil [64 mmHg (8.5 kPa), p < 0.001]. The systolic arterial pressure measured throughout all time points was higher with thiafentanil than with etorphine (p = 0.04). The difference varied from 30 mmHg at 20 minutes after recumbency to 14 mmHg (standard error difference 2.7 mmHg) at 40 minutes after recumbency. Mean and diastolic arterial pressures were significantly higher with thiafentanil at 20 and 25 minute measurement points only (p < 0.001).ConclusionsBoth drugs caused clinically relevant hypoxaemia; however, it was less severe with thiafentanil. Ventilation was adequate. Hypertension was greater and immobilization scores were lower with thiafentanil.  相似文献   

17.
ObjectiveTo compare the cardiopulmonary effects of the opioids etorphine and thiafentanil for immobilization of impala.Study designTwo-way crossover, randomized study.AnimalsA group of eight adult female impala.MethodsImpala were given two treatments: 0.09 mg kg–1 etorphine or 0.09 mg kg–1 thiafentanil via remote dart injection. Time to recumbency, quality of immobilization and recovery were assessed. Respiratory rate, heart rate (HR), mean arterial blood pressure (MAP) and arterial blood gases were measured. A linear mixed model was used to analyse the effects of treatments, treatments over time and interactions of treatment and time (p < 0.05).ResultsTime to recumbency was significantly faster with thiafentanil (2.0 ± 0.8 minutes) than with etorphine (3.9 ± 1.6 minutes; p = 0.007). Both treatments produced bradypnoea, which was more severe at 5 minutes with thiafentanil (7 ± 4 breaths minute–1) than with etorphine (13 ± 12 breaths minute–1; p = 0.004). HR increased with both treatments but significantly decreased over time when etorphine (132 ± 17 to 82 ± 11 beats minute–1) was compared with thiafentanil (113 ± 22 to 107 ± 36 beats minute–1; p < 0.001). Both treatments caused hypertension which was more profound with thiafentanil (mean overall MAP = 140 ± 14 mmHg; p < 0.001). Hypoxaemia occurred with both treatments but was greater with thiafentanil [PaO2 37 ± 13 mmHg (4.9 kPa)] than with etorphine [45 ± 16 mmHg (6.0 kPa)] 5 minutes after recumbency (p < 0.001). After 30 minutes, PaO2 increased to 59 ± 10 mmHg (7.9 kPa) with both treatments (p < 0.001).Conclusions and clinical relevanceThe shorter time to recumbency with thiafentanil may allow easier and faster retrieval in the field. However, thiafentanil caused greater hypertension, and ventilatory effects during the first 10 minutes, after administration.  相似文献   

18.
ObjectiveThis study aimed to evaluate the benefit and specifically the feasibility of using ultrasound in ophthalmologic periconal block, and the occurrence of complications.Study designProspective experimental study.AnimalsTen healthy New Zealand White rabbits (6–8 months of age), weighing 2.0–3.5 kg.MethodsRabbits were anesthetized by intramuscular injection of acepromazine (1 mg kg−1), ketamine (30 mg kg−1) and xylazine (3 mg kg−1). Ultrasound-assisted periconal block with lidocaine was performed on 18 eyes. Intraocular pressure was measured by applanation tonometry whereas corneal sensitivity was assessed using an esthesiometer, before and after each periconal anesthesia.ResultsIn all 18 eyes, it was possible to adequately visualize the needle shaft within the periconal space, as well as muscular cone, optic nerve and local anesthetic solution spread. Lidocaine 2% without epinephrine (0.79 ± 0.19 mL) was injected into the periconal space. There was no statistical difference between the intraocular pressure (mean ± SD) measured before (10.9 ± 2.9 mmHg) and after (11.9 ± 3.8 mmHg) the periconal anesthesia (p = 0.38). The effectiveness of the ultrasound-assisted technique was shown according to the values for corneal sensitivity, assessed before and after periconal anesthesia (p < 0.0001). Complications were not observed in this study.ConclusionsEye ultrasonography allowed visualization of all anatomic structures necessary to perform a periconal block, as well as the needle insertion and anesthetic spread in real time. Further studies are required to prove the real potential of ultrasound for reducing the incidence of complications associated with ophthalmic blocks, especially when anatomic disorders of the eye could potentially increase the risk.Clinical relevanceUltrasonography is a painless, noninvasive tool that may improve safety of ophthalmic regional blocks, potentially by reducing the prevalence of globe perforation or penetration of the optic nerve associated with the needle-based techniques.  相似文献   

19.
ObjectiveTo investigate the relationship between oxygen administration and ventilation in rabbits administered intramuscular alfaxalone–dexmedetomidine–midazolam.Study designProspective, randomized, blinded study.AnimalsA total of 25 New Zealand White rabbits, weighing 3.1–5.9 kg and aged 1 year.MethodsRabbits were anesthetized with intramuscular alfaxalone (4 mg kg–1), dexmedetomidine (0.1 mg kg–1) and midazolam (0.2 mg kg–1) and randomized to wait 5 (n = 8) or 10 (n = 8) minutes between drug injection and oxygen (100%) administration (facemask, 1 L minute–1). A control group (n = 9) was administered medical air 10 minutes after drug injection. Immediately before (PREoxy/air5/10) and 2 minutes after oxygen or medical air (POSToxy/air5/10), respiratory rate (fR), pH, PaCO2, PaO2, bicarbonate and base excess were recorded by an investigator blinded to treatment allocation. Data [median (range)] were analyzed with Wilcoxon, Mann–Whitney U and Kruskal–Wallis tests and p < 0.05 considered significant.ResultsHypoxemia (PaO2 < 88 mmHg, 11.7 kPa) was observed at all PRE times: PREoxy5 [71 (61–81) mmHg, 9.5 (8.1–10.8) kPa], PREoxy10 [58 (36–80) mmHg, 7.7 (4.8–10.7) kPa] and PREair10 [48 (32–64) mmHg, 6.4 (4.3–8.5) kPa]. Hypoxemia persisted when breathing air: POSTair10 [49 (33–66) mmHg, 6.5 (4.4–8.8) kPa]. Oxygen administration corrected hypoxemia but was associated with decreased fR (>70%; p = 0.016, both groups) and hypercapnia (p = 0.016, both groups). Two rabbits (one per oxygen treatment group) were apneic (no thoracic movements for 2.0–2.5 minutes) following oxygen administration. fR was unchanged when breathing air (p = 0.5). PaCO2 was higher when breathing oxygen than air (p < 0.001).Conclusions and clinical relevanceEarly oxygen administration resolved anesthesia-induced hypoxemia; however, fR decreased and PaCO2 increased indicating that hypoxemic respiratory drive is an important contributor to ventilation using the studied drug combination.  相似文献   

20.
ObjectiveTo determine the minimum infusion rate (MIR) of alfaxalone required to prevent purposeful movement of the extremities in response to noxious stimulation.Study DesignProspective, experimental.AnimalsEight healthy goats; four does and four wethers.MethodsAnaesthesia was induced with alfaxalone 3 mg kg−1 intravenously (IV). A continuous IV infusion of alfaxalone, initially at 0.2 mg kg−1 minute−1, was initiated. Following endotracheal intubation the goats breathed spontaneously via a circle breathing circuit delivering supplementary oxygen. The initial infusion rate was maintained for 30 minutes before testing for responses. The stimulus was clamping on the proximal (soft) part of one digit of the hoof with Vulsellum forceps for 60 seconds. In the absence or presence of purposeful movement of the extremities, the infusion rate was reduced or increased by 0.02 mg kg−1 minute−1 and held constant for 30 minutes before claw-clamping again. Alfaxalone MIR was calculated as the mean of the infusion rates that allowed and abolished movement. Cardio-respiratory parameters were measured. Recovery from general anaesthesia was timed and quality scored. Results are presented as median (range).ResultsThe MIR of alfaxalone was 0.16 (0.14–0.18) mg kg−1 minute−1 or 9.6 (8.4–10.8) mg kg−1 hour−1. Induction of and recovery from anaesthesia were excitement-free. Cardio-respiratory changes were minimal, although compared to baseline HR increased, and at 2 minutes post-induction, (prior to oxygen supplementation), PaO2 decreased significantly from 84 (80–88) to 70 (51–72) mmHg [11.2 (10.7–11.7) to 9.3 (6.8–9.6) kPa]. Sporadic muscle twitches, unrelated to depth of anaesthesia, were observed during the period of general anaesthesia. Time (minutes) to sternal recumbency and standing were 4.0 (3.0–10.0) and 41.5 (25.0–57.0) respectively.Conclusions and Clinical RelevanceAlfaxalone can be used for total intravenous anaesthesia (TIVA) in goats and is associated with minimal adverse effects. Oxygen supplementation is advised, especially when working at higher altitudes.  相似文献   

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