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1.
Most methods for determining cardiac output (CO) have limited application in clinical practice due to the invasive techniques required. This study compared the thermodilution technique (TDCO) with three noninvasive methods for determining CO in anesthetized dogs: transthoracic bioimpedance (BICO), partial CO2 rebreathing (NICO), and transesophageal echocardiography (TEECO). TDCO was compared to BICO, NICO, and TEECO in six adult sevoflurane anesthetized beagle dogs (9.1–13.0 kg). All dogs were administered midazolam [0.3 mg kg?1, intravenously (IV)] and butorphanol (0.1 mg kg?1 IV), followed by ketamine (5.0 mg kg–1 IV) and sevoflurane in nitrous oxide (1 L minute–1) and oxygen (1 L minute–1) and mechanically ventilated. Dogs were maintained at 2.2% end‐tidal sevoflurane (ETsev) concentration for instrumentation and baseline measurements. Low (5.0% ETsev), intermediate (3.3% ETsev), and high cardiac output values were achieved by varying the end‐tidal sevoflurane concentration and the administration of dobutamine (3–10 g kg–1 minute–1 and 2.2% ETsev). A minimum of thirty data sets was obtained for each comparison. The correlation coefficients when compared to TDCO were 0.684 for BICO (p < 0.0001), 0.883 for NICO (p < 0.0001), and 0.991 for TEECO (p < 0.0001). Cardiac output values ranged 50–444 mL kg–1 minute–1 for TDCO, 100–253 mL kg–1 minute–1 for BICO, 64–214 mL kg–1 minute–1 for NICO, and 52–401 mL kg–1 minute–1 for TEECO. The differences when compared to TDCO ranged – 62–235 mL kg?1minute?1 for BICO, 18–220 mL kg?1 minute?1 for NICO, and – 35–32 mL kg–1 minute–1 for TEECO. Differences were maximum at the highest CO in BICO and NICO. In conclusion, this study demonstrated that BICO and NICO underestimate CO in sevoflurane anesthetized dogs. TEECO is a viable noninvasive method for determining CO in sevoflurane anesthetized dogs.  相似文献   

2.
ObjectiveTo compare cardiac output (CO) measured by Doppler echocardiography and thermodilution techniques in spontaneously breathing dogs during continuous infusion of propofol. To do so, CO was obtained using the thermodilution method (COTD) and Doppler evaluation of pulmonary flow (CODP) and aortic flow (CODA).Study designProspective cohort study.AnimalsEight adult dogs weighing 8.3 ± 2.0 kg.MethodsPropofol was used for induction (7.5 ± 1.9 mg kg?1 IV) followed by a continuous rate infusion at 0.7 mg kg?1 minute?1. The animals were positioned in left lateral recumbency on an echocardiography table that allowed for positioning of the transducer at the 3rd and 5th intercostal spaces of the left hemithorax for Doppler evaluation of pulmonary and aortic valves, respectively. CODP and CODA were calculated from pulmonary and aortic velocity spectra, respectively. A pulmonary artery catheter was inserted via the jugular vein and positioned inside the lumen of the pulmonary artery in order to evaluate COTD. The first measurement of COTD, CODP and CODA was performed 30 minutes after beginning continuous infusion (T0) and then at 15‐minute intervals (T15, T30, T45 and T60). Numeric data were submitted to two‐way anova for repeated measurements, Pearson’s correlation coefficient and Bland &; Altman analysis. Data are presented as mean ± SD.ResultsAt T0, COTD was lower than CODA. CODA was higher than COTD and CODP at T30, T45 and T60. The difference between the COTD and CODP, when all data were included, was ?0.04 ± 0.22 L minute?1 and Pearson’s correlation coefficient (r) was 0.86. The difference between the COTD and CODA was ?0.87 ± 0.54 L minute?1 and r = 0.69. For COTD and CODP, the difference was ?0.82 ± 0.59 L minute?1 and r = 0.61.ConclusionDoppler evaluation of pulmonary flow was a clinically acceptable method for assessing the CO in propofol‐anesthetized dogs.  相似文献   

3.
Studies evaluating the effects of dobutamine in horses do not consistently report increases in cardiac output despite increases in arterial blood pressure. The concurrent administration of the α2 agonist clonidine, in people, inhibited the chronotropic effects of dobutamine and increased left ventricular stroke work ( Zimpfer et al. 1982 ). Our study was performed to determine if pre‐medication with an α2 agonist affects the response to dobutamine in anaesthetized horses. Eleven horses were anaesthetized on four separate occasions for one of four randomly assigned treatments; (I) no xylazine, no dobutamine (II) xylazine, no dobutamine (III) no xylazine, dobutamine, and (IV) xylazine, dobutamine. Horses received 0.02 mg kg?1 of butorphanol IV 10 minutes prior to anesthetic induction. Two minutes prior to induction, groups II and IV received 0.5 mg kg?1 of IV xylazine. Anaesthesia was induced with 6–7 mg kg?1 of thiopental and maintained with halothane. End‐tidal halothane concentrations were maintained between 1.1 and 1.2% in groups I and III, and 0.9–1.0% for groups II and IV. Heart rate, cardiac output, right atrial pressure, and systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressure were recorded 30 minutes after beginning halothane anaesthesia (T10). Cardiac output was estimated using Lithium dilution ( Linton et al. 2000 ). Baseline measurements were repeated twice, at 5‐minute intervals (T5 and T0). At time 0 (T0), an IV infusion of either saline (100 mL hour?1) or dobutamine (0.001 mg kg?1 minute?1) was started and data recorded at 5‐minute intervals for 30 minutes (T5 – T30). Stroke volume and systemic vascular resistance (SVR) were calculated. Data were analysed using repeated measures anova (p < 0.01 significant) and Newman–Keuls for multiple comparisons. Cardiac output and stroke volume increased over time in groups III and IV. Cardiac index was higher in groups III and IV than in groups I and II from T10 until completion of the study. Estimates of cardiac index at T30 for groups I–IV were 45 ± 9, 46 ± 11, 71 ± 11, and 78 ± 19 mL kg?1 minute?1, respectively (mean ± SD). Stroke index was higher in groups III and IV than in groups I and II from T15 to T30. Values for stroke index at T30 for groups I–IV were 0.98 ± 0.19, 1.11 ± 0.18, 1.46 ± 0.21, 1.74 ± 0.33 mL kg?1. Heart rate decreased from T10–T30 in groups I and II. Heart rate was greater in groups I and III than in groups II and IV at T5 and T0. Values for heart rate at T0 for groups I–IV were 48 ± 5, 42 ± 5, 50 ± 4, 43 ± 4 beats minute?1. Systolic arterial pressure, DAP and MAP were higher in groups III and IV than in groups I and II from T5 to T30. There were no differences in SVR between groups. Dobutamine at 0.001 mg kg?1 minute?1 increased cardiac output, blood pressure, and stroke volume. Premedication with xylazine at 0.5 mg kg?1 did not appear to affect the response to dobutamine.  相似文献   

4.
Objective To quantify the vapour output of the Komesaroff machine when using sevoflurane and to determine its performance for inducing and maintaining sevoflurane anaesthesia in dogs. Study design Prospective experimental study. Animals Six clinically normal beagles, aged 3–6 years and weighing 20 ± 1.65 kg (mean ± SEM). Methods The first study was performed using five Komesaroff vaporizers to measure the sevoflurane concentration delivered at each tap setting (I to IV) at 5, 10, 15, 20, 25, 30 and 35 minutes. For this study a ventilator was connected to the Komesaroff machine and set to deliver a tidal volume of 250 mL at 10 cycles minute?1; oxygen flow was 100 mL minute?1. A three‐litre reservoir bag was attached to the Y‐piece connector to act as a lung model. In the second study anaesthesia was induced in dogs with sevoflurane delivered by face‐mask mask and carried in 2 L minute?1 100% oxygen and with the vaporizer set at the fully open position. The quality and speed of induction were recorded. After orotracheal intubation, anaesthesia was maintained for 60 minutes with sevoflurane using an oxygen flow of 100 mL minute?1. The dogs were allowed to breathe spontaneously. The respiratory rate (RR), heart rate (HR), oesophageal temperature, systolic (SAP) mean (MAP) and diastolic (DAP) arterial pressure, end‐tidal CO2 concentration (Fe ′CO2) end‐tidal (Fe ′SEVO) and peak‐inspired (Fi SEVO) percentages of sevoflurane, and vaporizer tap setting were recorded every 5 minutes during anaesthesia. Results The delivery of sevoflurane was constant for each vaporizer setting. The mean output of sevoflurane was 0.44 ± 0.01% for setting I, 2.59 ± 0.18% for setting II, 3.28 ± 0.22% for setting III and 3.1 ± 0.5% for setting IV. In the second study, the mean induction time was 7.72 ± 0.60 minutes and the quality of the induction was good in all dogs. The mean vaporizer tap setting for the maintenance of anaesthesia was 3.48 ± 0.12 and the mean values for Fe ′SEVO and Fi SEVO were 2.42 ± 0.04% and 2.87 ± 0.06%, respectively. The pedal withdrawal reflex persisted throughout anaesthesia. Conclusions It proved impossible to produce surgical anaesthesia with sevoflurane delivered by the Komesaroff machine despite the highest possible sevoflurane concentration being delivered. Clinical relevance Sevoflurane delivered from the Komesaroff machine cannot be relied upon to maintain surgical anaesthesia in spontaneously breathing dogs.  相似文献   

5.
Objective To measure the effects of dobutamine infusion on fetal oxygenation during isoflurane anaesthesia in pregnant ewes. Study design Prospective randomized experimental study. Animals Seven clinically normal adult pregnant Rambouillet‐Dorset cross ewes with fetuses of 117–122 days gestational age. Methods The ewes were anaesthetized with ketamine (2 mg kg?1) IM, and isoflurane (FE′ISO 2.0%) in oxygen. After instrumentation and stabilization, dobutamine was infused at 4 µg kg?1minute?1 for 60 minutes and 10 µg kg?1minute?1 for 60 minutes in random order, separated by a 20‐minute washout period. Catheters were placed in the maternal and fetal carotid arteries; these were used for continuous blood pressure measurement and intermittent blood sampling. Results Maternal mean systemic carotid arterial pressure was 60 mm Hg prior to dobutamine infusion. After 5 minutes of dobutamine infusion, fetal oxygen saturation increased (p < 0.05) from 0.62 (0.17–0.71, minimum–maximum) to 0.72 (0.28–0.78) at a dose of 4 µg kg?1minute?1 and to 0.70 (0.20–0.73) at a dose of 10 µg kg?1minute?1. These increases were maintained during the infusion and were not significantly different between doses. Maternal oxygen saturation remained constant at 1.0 before and during all infusions. Although maternal heart rate and blood pressure increased (p < 0.05) by 90% and 25%, respectively, with dobutamine, this stimulant effect was not evident in the corresponding fetal variables. Maternal haemoglobin concentration increased 30% (p < 0.05) with each infusion. Conclusions Dobutamine at 4 µg kg?1minute?1 increases fetal oxygenation that is not improved by a dose of 10 µg kg?1minute?1. This increase is largely due to an increase in maternal haemoglobin concentration that, in turn, increases oxygen delivery to the placenta. Clinical relevance The use of dobutamine to treat hypotension in pregnant sheep during isoflurane anaesthesia improves fetal oxygenation. This may be true in other species.  相似文献   

6.
Collateral venous pathways develop in dogs with obstruction or increased blood flow resistance at any level of the caudal vena cava in order to maintain venous drainage to the right atrium. The purpose of this retrospective study was to describe the sites, causes of obstruction, and configurations of venous collateral pathways for a group of dogs with caudal vena cava obstruction. Computed tomography databases from two veterinary hospitals were searched for dogs with a diagnosis of caudal vena cava obstruction and multidetector row computed tomographic angiographic (CTA) scans that included the entire caudal vena cava. Images for each included dog were retrieved and collateral venous pathways were characterized using image postprocessing and a classification system previously reported for humans. A total of nine dogs met inclusion criteria and four major collateral venous pathways were identified: deep (n = 2), portal (n = 2), intermediate (n = 7), and superficial (n = 5). More than one collateral venous pathway was present in 5 dogs. An alternative pathway consisting of renal subcapsular collateral veins, arising mainly from the caudal pole of both kidneys, was found in three dogs. In conclusion, findings indicated that collateral venous pathway patterns similar to those described in humans are also present in dogs with caudal vena cava obstruction. These collateral pathways need to be distinguished from other vascular anomalies in dogs. Postprocessing of multidetector‐row CTA images allowed delineation of the course of these complicated venous pathways and may be a helpful adjunct for treatment planning in future cases.  相似文献   

7.
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   

8.
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   

9.
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   

10.
A noninvasive method for quantifying hydration status would be helpful for clinical management and for research applications in dogs. This prospective, experimental, pilot study aimed to assess the feasibility of ultrasonographic measurement of the caudal vena cava to aorta ratio as a method for quantifying volume depletion in dogs. In 12 normal beagle dogs, furosemide was administered intravenously at a dose of 1 mg/kg, every 2 h, for 8 h, to induce consecutive volume depletion. Every 30 min after administration, ultrasonographic images of the caudal vena cava and aorta, and physical and biological parameters related to dehydration were acquired. On transverse and longitudinal planes of caudal vena cava and aorta images, the height and area of the caudal vena cava and aorta were measured to calculate the caudal vena cava/aorta ratios. All images were acquired by approaching from the right intercostal space with the dogs in left lateral recumbency. A negative correlation was present between the percentage of weight loss in dogs and all four investigated caudal vena cava/aorta ratios (transverse plane width of the caudal vena cava [TW]/aorta; transverse plane height of caudal vena cava [TH]/aorta; longitudinal plane area of the caudal vena cava [TA]/aorta; and longitudinal plane maximal height of the caudal vena cava [L]/aorta). Significant differences (P < 0.001) were seen between dogs with and without clinical signs of dehydration for all caudal vena cava/aorta ratios. Findings indicated that ultrasonographic caudal vena cava/aorta ratios are feasible methods for quantifying volume depletion and for use as an adjunct to standard subjective methods for estimating hydration status in dogs.  相似文献   

11.
Caudal vena cava duplication has been rarely reported in small animals. The purpose of this retrospective study was to describe characteristics of duplicated caudal vena cava in a large group of dogs. Computed tomography (CT) and ultrasound databases from two hospitals were searched for canine reports having the diagnosis “double caudal vena cava.” One observer reviewed CT images for 71 dogs and two observers reviewed ultrasound images for 21 dogs. In all CT cases, the duplication comprised two vessels that were bilaterally symmetrical and approximately the same calibre (similar to Type I complete duplication in humans). In all ultrasound cases, the duplicated caudal vena cava appeared as a distinct vessel running on the left side of the abdominal segment of the descending aorta and extending from the left common iliac vein to the left renal vein. The prevalence of caudal vena cava duplication was 0.46% for canine ultrasound studies and 2.08% for canine CT studies performed at these hospitals. Median body weight for affected dogs was significantly lower than that of unaffected dogs (P < 0.0001). Breeds with increased risk for duplicated caudal vena cava were Yorkshire Terrier (odds ratio [OR] = 6.41), Poodle (OR = 7.46), West Highland White Terrier (OR = 6.33), and Maltese (OR = 3.87). Presence of a duplicated caudal vena cava was significantly associated with presence of extrahepatic portosystemic shunt(s) (P < 0.004). While uncommon in dogs, caudal vena cava duplication should be differentiated from other vascular anomalies when planning surgeries and for avoiding misdiagnoses.  相似文献   

12.
The purpose of this study was to compare the echocardiographic Doppler blood pressure and heart rate effects of 1:1 thiopental/propofol with thiopental and propofol, when used as anesthesia‐induction agents. Seven healthy dogs (six Beagles and one Pembroke Welsh Corgi), ranging in age from 1 to 9 years and weighing 14.2 ± 2.4 kg (mean ± SD), were used during the study. In a cross‐over study design with a minimum drug interval of 3 days, each dog received propofol, thiopental, or a mixture of propofol–thiopental IV until each dog received all the three anesthetic agents. An initial dose (propofol 4.9 ± 0.8 mg kg?1; thiopental 12.9 ± 2.4 mg kg?1; propofol–thiopental 2.3 ± 0.3 mg kg?1 (P)?5.7 ± 0.8 mg kg?1 (T)) of each anesthetic agent was titrated IV until intubation was accomplished. Echocardiographic Doppler blood pressure and heart rate variables were recorded prior to anesthesia and at 1, 5, and 10 minutes after induction of anesthesia. anova and the Bonferroni's t‐test were used to evaluate the groups for differences. Alpha was <0.05. There was no significant effect of treatment on systolic or diastolic ventricular wall thickness, septal thickness, left atrial diameter, or systolic left ventricular diameter. There was a tendency for diastolic left ventricular diameter to decrease over time. There was a tendency for heart rate to increase with a significant difference at the 10‐minute time period between propofol (109 ± 26 beats minute?1) and thiopental (129 ± 23 beats minute?1). At the 10‐minute recording period, heart rate following the propofol/thiopental mixture (110 ± 34 beats minute?1) was closer to that following propofol than to that following thiopental. With all induction agents, indirect blood pressure tended to decrease over time (p = 0.005); however, there was no difference between the groups. The changes observed were not considered to be of clinical significance. The propofol/thiopental mixture produces similar changes in echocardiographic variables when compared to propofol or thiopental, and could be substituted for propofol for induction of anesthesia in dogs.  相似文献   

13.
ObjectiveTo determine whether dobutamine, norepinephrine or phenylephrine infusions alleviate hypotension in isoflurane-anaesthetized dogs administered dexmedetomidine with vatinoxan.Study designBalanced, randomized crossover trial.AnimalsA total of eight healthy Beagle dogs.MethodsEach dog was anaesthetized with isoflurane (end-tidal isoflurane 1.3%) and five treatments: dexmedetomidine hydrochloride (2.5 μg kg–1) bolus followed by 0.9% saline infusion (DEX-S); dexmedetomidine and vatinoxan hydrochloride (100 μg kg–1) bolus followed by an infusion of 0.9% saline (DEX-VAT-S), dobutamine (DEX-VAT-D), norepinephrine (DEX-VAT-N) or phenylephrine (DEX-VAT-P). The dexmedetomidine and vatinoxan boluses were administered at baseline (T0) and the treatment infusion was started after 15 minutes (T15) if mean arterial pressure (MAP) was < 90 mmHg. The treatment infusion rate was adjusted every 5 minutes as required. Systemic haemodynamics were recorded at T0 and 10 (T10) and 45 (T45) minutes. A repeated measures analysis of covariance model was used.ResultsMost dogs had a MAP < 70 mmHg at T0 before treatment. Treatments DEX-S and DEX-VAT all significantly increased MAP at T10, but systemic vascular resistance index (SVRI) was significantly higher and cardiac index (CI) lower after DEX-S than after DEX-VAT. CI did not significantly differ between DEX-S and DEX-VAT-S at T45, while SVRI remained higher with DEX-S. Normotension was achieved by all vasoactive infusions in every dog, whereas MAP was below baseline with DEX-VAT-S, and higher than baseline with DEX-S at T45. Median infusion rates were 3.75, 0.25 and 0.5 μg kg–1 minute–1 for dobutamine, norepinephrine and phenylephrine, respectively. Dobutamine and norepinephrine increased CI (mean ± standard deviation, 3.35 ± 0.70 and 3.97 ± 1.24 L minute–1 m–2, respectively) and decreased SVRI, whereas phenylephrine had the opposite effect (CI 2.13 ± 0.45 L minute–1 m–2).Conclusions and clinical relevanceHypotension in isoflurane-anaesthetized dogs administered dexmedetomidine and vatinoxan can be treated with either dobutamine or norepinephrine.  相似文献   

14.
Chronically sustained systemic hypertension in dogs can damage the kidneys, eye, brain, heart, and vessels. In human medicine, systemic hypertension has been implicated as the most common risk factor for aorta dilation, which can progress to an aneurysm. Abdominal ultrasound has been commonly used to monitor the size of the abdominal aorta in people with systemic hypertension. In this retrospective cross‐sectional abdominal ultrasound study, evaluation of the size of the abdominal aorta relative to the caudal vena cava was performed in 18 control dogs and 128 dogs with confirmed systemic hypertension. Preexisting conditions contributing to systemic hypertension in these dogs were renal disease, hyperadrenocorticism, diabetes mellitus, adrenal tumors, and previous administration of phenylpropanolamine or palladia. The abdominal aorta and caudal vena cava were assessed from longitudinal images cranial to the trifurcation with measurements made from outer border to outer border of the walls, being careful not to compress the caudal vena cava that would alter its size. Our hypothesis was the ratio of the diameter of the abdominal aorta to caudal vena cava would be higher in dogs with systemic hypertension compared to dogs with normal blood pressure. The mean abdominal aorta‐caudal vena cava ratio was 1.028 in control dogs with a normal blood pressure and 1.515 in dogs with systemic hypertension. In dogs with confirmed systemic hypertension, the abdominal aorta was dilated compared to the caudal vena cava in the caudal abdomen. An increase in the abdominal aorta‐caudal vena cava ratio in a dog should raise suspicion for the presence of systemic hypertension and prompt evaluation of blood pressure.  相似文献   

15.
A central eyeball position is often required during sedation or anaesthesia to facilitate examination of the eye. However, use of neuromuscular blockade to produce a central eye position may result in depressed ventilation. This study evaluated the eyeball position, muscle relaxation and changes in ventilation during general anaesthesia after the IV administration of 0.1 mg kg?1 rocuronium. With client consent, 12 dogs of different breeds, body mass 27.2 ± 11.8 kg, aged 5.6 ± 2.8 years (mean ± SD) were anaesthetized for ocular examination. Pre‐anaesthetic medication was 0.01 mg kg?1 medetomidine and 0.2 mg kg?1 butorphanol IV. Anaesthesia was induced with propofol to effect and maintained with 10 mg kg?1 hour?1 propofol by infusion. The dogs were placed in left lateral recumbency, their trachea intubated and connected to a circle breathing system (Fi O2 = 1.0). All dogs breathed spontaneously. The superficial peroneal nerve of the right hind leg was stimulated every 15 seconds with a train‐of‐four (TOF) stimulation pattern and neuromuscular function was assessed with an acceleromyograph (TOF‐Guard). Adequacy of ventilation was measured with the Ventrak 1550. After 10 minutes of anaesthesia to allow stabilisation of baseline values, 0.1 mg kg?1 rocuronium was administered IV. Minute volume (Vm ), tidal volume (Vt ), respiratory rate (RR), Pe ′CO2 and maximal depression of T1 and TOF ratio were measured. Data were analysed using a paired t‐test. The changes in the eyeball position were recorded. A total of 100 ± 33 seconds after the injection of rocuronium, T1 was maximally depressed to 62 ± 21% and the TOF ratio to 42 ± 18% of baseline values. Both variables returned to baseline after 366 ± 132 seconds (T1) and 478 ± 111 seconds (TOF). There was no significant reduction in Vm (2.32 ± 1.1 L minute?1), Vt (124.1 ± 69.3 mL) and RR (10 ± 3.8 breaths minute?1) and no increase in Pe ′CO2 (6.5 ± 2.1 kPa (48.8 ± 16.1 mm Hg)) throughout the procedure. The eyeball rotated to a central position 35 ± 7 seconds after rocuronium IV and remained there for a minimum of 20 ± 7 minutes in all dogs. We conclude that rocuronium at a dose of 0.1 mg kg?1 can be administered to dogs IV with minimal changes in ventilatory variables. The eyeball is fixed in a central position for at least 20 minutes, which greatly facilitates clinical examination.  相似文献   

16.
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17.
S(+) ketamine, one of the two enantiomers of racemic ketamine, is a phencyclidine derivative that induces amnesia and analgesia. Its activity is related to blockade of NMDA receptors and some opioid action. We compared anesthetic induction and recovery quality with S(+) ketamine in combination with diazepam or midazolam in 10 dogs (ASA 1) admitted for elective surgery. After all clinical examinations, the dogs were separated into two groups (G I and G II). All animals received acepromazine (0.1 mg kg?1) and fentanyl (5 µg kg?1) IM, 20 minutes before induction with S(+) ketamine (6 mg kg?1) and diazepam (0.5 mg kg?1) IV (G I) or midazolam 0.2 mg kg?1 (G II) IV. The doses of diazepam and midazolam were chosen according to the literature. All dogs were intubated and then maintained with halothane in oxygen at a vaporizer setting sufficient to maintain surgical anesthesia. Quality of induction, time needed for intubation, heart rate, respiratory rate, SpO2, time to extubation, and quality of recovery were evaluated. The results were analyzed by Student's t‐test. Smooth induction and recovery were observed in all animals. The time to intubation was 45 ± 20 (GI) and 25 ± 6 seconds (GII), HR was 122 ± 12 (GI) and 125 ± 7 beats minute?1 (GII), RR was 17 ± 2 (GI) and 21 ± 3 breaths minute?1 (GII), SpO2 was 96 ± 2 (GI) and 94 ± 1% (GII), time to extubation was 7 ± 3 (GI) and 4 ± 1 minutes (GII). No statistical differences were found in analyses, although time to intubation was less in GII. The results suggested that both combinations could be used safely for anesthetic induction in healthy dogs.  相似文献   

18.
Non‐steroidal anti‐inflammatory drugs may potentiate the opioid induced reduction in volatile anaesthetic requirements ( Gomez de Segura et al. 1998 ). This study determined the reduction in the MAC of isoflurane (ISO) produced by ketoprofen (KETO) in dogs anaesthetized with fentanyl (FENT) and ISO. Six healthy female crossbred dogs, weighing 13.5 ± 1.3 (mean ± SD) kg and aged 3.0 ± 0.9 years were studied. Approval of the study was obtained from the institutional ethics committee. Anaesthesia was induced in all dogs via a facemask with 5% ISO in 5 L minute?1 oxygen. The dogs' trachea were intubated and lungs were ventilated to maintain normocapnia (Pe ′CO2 4.7–6 kPa, 35–45 mm Hg). A heating pad was used to maintain body temperature. The animals were anaesthetized four times at one week intervals with the following anaesthetic and analgesic protocols randomly administered. Study 1, MAC (ISO); Isoflurane MAC. Study 2, MAC (ISO + FENT); dogs anaesthetized with ISO received a loading dose of 30 µg kg?1 FENT IV over 20 minutes followed by a maintenance infusion of 0.2 µg kg?1 minute?1 FENT. Study 3, MAC (ISO + FENT + KETO1); as study 2 plus 1 mg kg?1 KETO. Study 4, MAC (ISO + FENT + KETO2); as study 2 plus 2 mg kg?1 KETO. The MAC was determined in duplicate by applying a standard electrical stimulus (50 V, 50 H2 over 60 seconds via two needles placed SC over the tarsus). The stimulus was applied 15 minutes after every step change in anesthetic concentration. The Wilcoxon test was applied to data to determine significant differences among MAC measurements. Fentanyl significantly decreased MAC (ISO) from 1.27% ± 0.02% to 0.73% ± 0.08%, a reduction of 42% (p < 0.05). Ketoprofen 1 mg kg?1 further decreased the MAC value (although not statistically significantly) with a reduction of 47% from MAC (ISO) (0.67% ± 0.13%) and 8% from MAC (ISO + FENT). When KETO 2 mg kg?1 was given, the reduction in MAC was 50% compared to MAC (ISO) (0.63% ± 0.08%; p < 0.05) and 14% compared to MAC (ISO + FENT) p < 0.05. Administration of KETO further reduces MAC (ISO) compared to levels observed with FENT alone. The observed reduction may have clinical advantages.  相似文献   

19.
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   

20.
Severe portal vascular anomalies have been reported previously accompanying azygos continuation of the caudal vena cava, polysplenia, and situs anomalies in dogs and people. Three dogs with portal vascular anomalies were identified by means of CT angiography as having portal vein aplasia with portal insertion into the caudal vena cava, azygos continuation of the caudal vena cava, and interruption of the pre‐hepatic caudal vena cava. This information confirms that complex embryological defects may occur in patients presenting for congenital portosystemic shunt, and that CT angiography is a non‐invasive method of completely evaluating these potentially non‐surgical portal vascular anomalies.  相似文献   

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