共查询到20条相似文献，搜索用时 62 毫秒
1.
Objective
To study the effects of MK-467, a peripheral α2-adrenoceptor antagonist, on sedation, heart rate and blood pressure after intramuscular (IM) coadministration with 25 μg kg?1 of dexmedetomidine in cats.Study design
Prospective, randomized, controlled, blinded, cross-over, experimental study.Animals
A total of eight healthy, adult, neutered male cats.Methods
Cats were administered five IM treatments at least 2 weeks apart, consisting of dexmedetomidine 25 μg kg?1 (D25), MK-467 600 μg kg?1 (M600) and D25 combined with 300, 600 and 1200 μg kg?1 of MK-467 (D25M300, D25M600 and D25M1200, respectively). Heart rate and direct arterial blood pressure were recorded via telemetry and sedation assessed prior to treatments and at intervals for 8 hours thereafter.Results
Heart rate decreased significantly after all treatments with dexmedetomidine and remained below baseline up to 240 (D25), 20 (D25M300) and 3 minutes (D25M600 and D25M1200). Mean arterial pressure (MAP) increased with D25, remained unchanged with M600 and decreased over time with all combination treatments. The highest and lowest MAP after each treatment were 168 ± 17 and 100 ± 14 (D25), 157 ± 18 and 79 ± 11 (D25M300), 153 ± 11 and 74 ± 10 (D25M600), 144 ± 12 and 69 ± 7 (D25M1200) and 136 ± 9 and 104 ± 13 mmHg (M600). All treatments with dexmedetomidine produced sedation although its duration was significantly reduced by the addition of MK-467.Conclusions and clinical relevance
Dexmedetomidine induced bradycardia and hypertension, which were attenuated by all three doses of MK-467. The duration of sedation was reduced by MK-467. MK-467 may improve the cardiovascular tolerance of IM dexmedetomidine in cats. 相似文献2.
Muriel Sacks Simone K. Ringer Andrea S. Bischofberger Sabrina M. Berchtold Regula Bettschart-Wolfensberger 《Veterinary anaesthesia and analgesia》2017,44(5):1128-1138
Objective
To compare the effects of two balanced anaesthetic protocols (isoflurane–dexmedetomidine versus medetomidine) on sedation, cardiopulmonary function and recovery in horses.Study design
Prospective, blinded, randomized clinical study.Animals
Sixty healthy adult warm blood horses undergoing elective surgery.Methods
Thirty horses each were sedated with dexmedetomidine 3.5 μg kg?1 (group DEX) or medetomidine 7 μg kg?1 (group MED) intravenously. After assessing and supplementing sedation if necessary, anaesthesia was induced with ketamine/diazepam and maintained with isoflurane in oxygen/air and dexmedetomidine 1.75 μg kg?1 hour?1 or medetomidine 3.5 μg kg?1 hour?1. Ringer's lactate (7–10 mL kg?1 hour?1) and dobutamine were administered to maintain normotension. Controlled mechanical ventilation maintained end-tidal expired carbon dioxide pressures at 40–50 mmHg (5.3–6.7 kPa). Heart rate, invasive arterial blood pressure, inspired and expired gas composition and arterial blood gases were measured. Dexmedetomidine 1 μg kg?1 or medetomidine 2 μg kg?1 was administered for timed and scored recovery phase. Data were analysed using two-way repeated-measures analysis of variance and chi-square test. Significance was considered when p ≤ 0.05.Results
In group DEX, significantly more horses (n = 18) did not fulfil the sedation criteria prior to induction and received one or more supplemental doses, whereas in group MED only two horses needed one additional bolus. Median (range) total sedation doses were dexmedetomidine 4 (4–9) μg kg?1 or medetomidine 7 (7–9) μg kg?1. During general anaesthesia, cardiopulmonary parameters did not differ significantly between groups. Recovery scores in group DEX were significantly better than in group MED.Conclusions and clinical relevance
Horses administered dexmedetomidine required more than 50% of the medetomidine dose to reach equivalent sedation. During isoflurane anaesthesia, cardiopulmonary function was comparable between the two groups. Recovery scores following dexmedetomidine were better compared to medetomidine. 相似文献3.
Flavia Restitutti M. Johanna Kaartinen Marja R. Raekallio Otto Wejberg Emmi Mikkola Jerome R.E. del Castillo Mika Scheinin Outi M. Vainio 《Veterinary anaesthesia and analgesia》2017,44(3):417-426
Objective
We investigated the plasma concentrations and cardiovascular effects of intramuscularly (IM) administered medetomidine, administered alone or with three different doses of MK-467.Study design
Prospective, randomized, open, crossover trial.Animals
Eight purpose-bred healthy Beagle dogs.Methods
Each dog was administered four treatments: medetomidine 20 μg kg–1 IM alone or mixed in the same syringe with MK-467 (200 μg kg–1, 400 μg kg–1 or 600 μg kg–1). Instrumentation was performed under standardized anaesthesia. The dogs were allowed to recover before measurement of baseline values. Composite sedation scores, cardiovascular variables, i.e., heart rate (HR), cardiac output (CO), mean arterial and central venous blood pressures (MAP and CVP) and arterial blood gases were recorded at baseline and for 60 minutes after treatment. Drug concentrations in venous plasma were analysed. Generalized linear mixed models for repeated measures with post hoc Bonferroni correction were used with statistical significance level set at α = 0.05.Results
All treatments initially demonstrated the effects of medetomidine: HR and CO decreased and CVP increased. MAP transiently increased and then significantly decreased from baseline with the two highest MK-467 doses. The cardiovascular effects of medetomidine disappeared more rapidly with MK-467 than with medetomidine alone. With medetomidine alone, sedation scores remained high until the end of the 60 minute follow-up. Maximum concentrations of medetomidine were more rapidly achieved and were higher with MK-467.Conclusions and clinical relevance
Initial haemodynamic effects of medetomidine were not prevented by MK-467, but these effects were attenuated and their duration shortened by MK-467, independently of dose. Absorption of medetomidine was accelerated by MK-467, when administered concomitantly IM, resulting in faster sedation; addition of MK-467 shortened the sedative effect of medetomidine. 相似文献4.
Ana C. Neves Juracy CB. Santos Júnior Rodrigo L. Marucio Monica Midon Stelio PL. Luna 《Veterinary anaesthesia and analgesia》2017,44(2):375-378
Objective
To evaluate three volumes of lidocaine for spermatic cord block to perform castration in cattle.Study design
Randomized blinded clinical study.Animals
Thirty mixed-breed Nellore cattle, aged 28–40 months and weighing 395 ± 21 (352–452) kg [mean ± standard deviation (range)].Methods
Cattle were restrained in a chute and allowed to stand without sedation. Three milliliters of 2% lidocaine without epinephrine were infiltrated subcutaneously at each site of scrotal incision in all animals. The animals were allocated to three groups of 10 animals each. Lidocaine 2% was injected into each spermatic cord using a volume of 2, 3 or 4 mL in groups A, B, or C, respectively. The total volumes of lidocaine used were 10, 12, and 14 mL in groups A, B, and C, respectively. The duration of surgery and the retraction of the testicle (scored as positive or negative according to retraction of the testicle) during the procedure were recorded. The data were statistically analyzed by one-way anova followed by Tukey’s and chi-square tests. Differences were considered significant when p < 0.05.Results
The mean surgical time was shorter in group C than in groups A and B (p < 0.001). In groups A, B and C, 90%, 60% and 10% of the animals showed retraction of the testicle, respectively. Fewer animals retracted the spermatic cord in group C than in group A (p = 0.002) and B (p = 0.02).Conclusions and clinical relevance
Optimal spermatic cord block was achieved by injection of 4 mL of 2% lidocaine 5 minutes before castration and following incisional infiltration of lidocaine, in adult cattle weighing about 400 kg. 相似文献5.
6.
Robert J. Brosnan Fabíola B. Fukushima Trung L. Pham 《Veterinary anaesthesia and analgesia》2017,44(3):577-588
Objective
N-butane and n-pentane can both produce general anesthesia. Both compounds potentiate γ-aminobutyric acid type A (GABAA) receptor function, but only butane inhibits N-methyl-d-aspartate (NMDA) receptors. It was hypothesized that butane and pentane would exhibit anesthetic synergy due to their different actions on ligand-gated ion channels.Study design
Prospective experimental study.Animals
A total of four Xenopus laevis frogs and 43 Sprague–Dawley rats.Methods
Alkane concentrations for all studies were determined via gas chromatography. Using a Xenopus oocyte expression model, standard two-electrode voltage clamp techniques were used to measure NMDA and GABAA receptor responses in vitro as a function of butane and pentane concentrations relevant to anesthesia. The minimum alveolar concentrations (MAC) of butane and pentane were measured separately in rats, and then pentane MAC was measured during coadministration of 0.25, 0.50 or 0.75 times MAC of butane. An isobole with 95% confidence intervals was constructed using regression analysis. A sum of butane and pentane that was statistically less than the lower-end confidence bound isobole indicated a synergistic interaction.Results
Both butane and pentane dose-dependently potentiated GABAA receptor currents over the study concentration range. Butane dose-dependently inhibited NMDA receptor currents, but pentane did not modulate NMDA receptors. Butane and pentane MAC in rats was 39.4 ± 0.7 and 13.7 ± 0.4 %, respectively. A small but significant (p < 0.03) synergistic anesthetic effect with pentane was observed during administration of either 0.50 or 0.75 × MAC butane.Conclusions
Butane and pentane show synergistic anesthetic effects in vivo consistent with their different in vitro receptor effects.Clinical relevance
Findings support the relevance of NMDA receptors in mediating anesthetic actions for some, but not all, inhaled agents. 相似文献7.
David Knazovicky Erika S. Helgeson Beth Case Andrea Thomson Margaret E. Gruen William Maixner B. Duncan X. Lascelles 《Veterinary anaesthesia and analgesia》2017,44(3):615-624
Objective
To evaluate replicate effects and test–retest reliability of mechanical and thermal quantitative sensory testing (QST) in normal dogs and dogs with osteoarthritis (OA)-associated pain.Study design
A prospective clinical study.Animals
A total of 54 client owned dogs (OA, n = 31; controls, n = 23).Methods
Mechanical [electronic von Frey (EVF) and blunt pressure] and thermal (hot and cold) sensory thresholds were obtained in dogs with OA-associated pain and control dogs at two visits, 7 days apart, to assess test–retest reliability. Thresholds were measured at the OA-affected joint (hip or stifle), over the tibial muscle and over the midpoint of the metatarsals. Five replicates were obtained for each modality at each site bilaterally.Results
Overall, there was no significant effect of replicates on QST response. EVF thresholds were significantly lower at the second visit in OA dogs at the affected and metatarsal sites (p = 0.0017 and p = 0.0014, respectively). Similarly for control dogs, EVF thresholds were significantly lower at the second visit at the metatarsal site (p = 0.001). Significantly higher hot thermal latencies were seen in OA dogs at the affected and tibial testing sites (p = 0.014 and p = 0.012, respectively), and in control dogs at the tibial site (p = 0.004).Conclusions
In QST, a replicate does not show a strong effect. However, QST results show variability over time, particularly for EVF and hot thermal stimuli.Clinical relevance
If QST is to be used clinically to evaluate a sensitized state, the variability over time needs to be accounted for in the study design. 相似文献8.
Kazumasu Sasaki Tatsushi Mutoh Tomoko Mutoh Yasuyuki Taki Ryuta Kawashima 《Veterinary anaesthesia and analgesia》2017,44(4):719-726
Objective
To evaluate the ability of a noninvasive cardiac output monitoring system with electrical velocimetry (EV) for predicting fluid responsiveness in dogs undergoing cardiac surgery.Study design
Prospective experimental trial.Animals
A total of 30 adult Beagle dogs.Methods
Stroke volume (SV), stroke volume variation (SVV) and cardiac index were measured using the EV device in sevoflurane-anaesthetized, mechanically ventilated dogs undergoing thoracotomies for experimental creation of right ventricular failure. The dogs were considered fluid responsive if stroke volume (SVI; indexed to body weight), measured using pulmonary artery thermodilution, increased by 10% or more after volume loading (10 mL kg–1). Relationships of SVV, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) with SVI were analysed to estimate fluid responsiveness.Results
Better prediction of fluid responsiveness, with a significant area under the receiver operating characteristic curve, was observed for SVV (0.85 ± 0.07; p = 0.0016) in comparison with CVP (0.65 ± 0.11; p = 0.17) or PAOP (0.60 ± 0.12; p = 0.35), with a cut-off value of 13.5% (84% specificity and 73% sensitivity).Conclusions and clinical relevance
SVV derived from EV is useful for identification of dogs that are likely to respond to fluids, providing valuable information on volume status under cardiothoracic anaesthesia. 相似文献9.
Daniel M. Sakai Manuel Martin-Flores Marta Romano Chia T. Tseng Luis Campoy Robin D. Gleed Jonathan Cheetham 《Veterinary anaesthesia and analgesia》2017,44(2):246-253
Objective
To determine if neuromuscular monitoring at the pelvic limb accurately reflects neuromuscular function in the larynx after administration of rocuronium in anesthetized dogs.Study design
Prospective experimental study.Animals
Six healthy Beagle dogs.Methods
Anesthesia was maintained in dogs with isoflurane and a continuous infusion of dexmedetomidine. Rocuronium (0.6 mg kg?1) was administered intravenously to induce neuromuscular block. Train-of-four (TOF) impulses were applied to the left recurrent laryngeal nerve (RLn) and the peroneal nerve (Pn). The evoked TOF ratio (TOFR; T4:T1) was measured with electromyography (EMG) simultaneously at the larynx and at the pelvic limb. Spontaneous recoveries of T1 to 25% (T125%) and 75% (T175%) of twitch height, and to TOFR of 0.70 and 0.90 (TOFR0.90) at each EMG site were compared.Results
Data from five dogs were analyzed. Times to T125% were similar at the pelvic limb and larynx when measured by EMG; time to T175% was slower at the larynx by 6 ± 4 minutes (p = 0.012). The larynx had a slower recovery to TOFR0.70 (41 ± 13 minutes) and TOFR0.90 (45 ± 13 minutes) than did the pelvic limb [29 ± 8 minutes (p = 0.011) and 33 ± 9 minutes (p = 0.003), respectively]. When the pelvic limb EMG returned to TOFR0.70 and TOFR0.90, the larynx EMG TOFR0.70 and TOFR0.90 values were 0.32 ± 0.12 (p = 0.001) and 0.38 ± 0.13 (p = 0.001), respectively.Conclusions and clinical relevance
After administration of rocuronium, neuromuscular function assessed by EMG recovered approximately 36% slower at the larynx than at the pelvic limb. The results in these dogs suggest that quantitative neuromuscular monitoring instrumented at a pelvic limb may be unable to exclude residual block at the larynx in anesthetized dogs. 相似文献10.
Alexandra F. Schütter Julia Tünsmeyer Sabine B.R. Kästner 《Veterinary anaesthesia and analgesia》2017,44(2):309-316
Objective
The aim of the study was to evaluate the influence of tramadol on acute nociception in dogs.Study design
Experimental, blinded, randomized, crossover study.Animals
Six healthy laboratory Beagle dogs.Methods
Dogs received three treatments intravenously (IV): isotonic saline placebo (P), tramadol 1 mg kg?1 (T1) and tramadol 4 mg kg?1 (T4). Thermal thresholds were determined by ramped contact heat stimulation (0.6 °C second?1) at the lateral thoracic wall. Mechanical thresholds (MT) were measured using a probe containing three blunted pins which were constantly advanced over the radial bone, using a rate of force increase of 0.8 N second?1. Stimulation end points were defined responses (e.g. skin twitch, head turn, repositioning, vocalization) or pre-set cut-out values (55 °C, 20 N). Thresholds were determined before treatment and at predetermined time points up to 24 hours after treatment. At each measurement point, blood was collected for determination of O-desmethyltramadol concentrations. The degree of sedation and behavioural side effects were recorded. Data were analysed by one-way anova and two-way anova for repeated measurements.Results
Thermal nociception was not influenced by drug treatment. Mechanical nociception was significantly increased between P and T1 at 120 and 240 minutes, and between P and T4 at 30, 60, 240 and 420 minutes. T1 and T4 did not differ. O-desmethyltramadol (M1) maximum plasma concentrations (Cmax) were 4.2 ± 0.8 ng mL?1 and 14.3 ± 2.8 ng mL?1 for T1 and T4, respectively. Times to reach maximum plasma concentrations (Tmax) were 27.6 ± 6.3 minutes for T1 and 32.1 ± 7.8 minutes for T4. No sedation occurred. There were signs of nausea and mild to moderate salivation in both groups.Conclusion and clinical relevance
Tramadol was metabolized marginally to O-desmethyltramadol and failed to produce clinically relevant acute antinociception. Therefore, the use of tramadol for acute nociceptive pain is questionable in dogs. 相似文献11.
Rachel C. Hector Marlis L. Rezende Khursheed R. Mama Eugene P. Steffey Heather K. Knych Ann M. Hess Juhana M. Honkavaara Marja R. Raekallio Outi M. Vainio 《Veterinary anaesthesia and analgesia》2017,44(4):755-765
Objective
To determine the effects of low and high dose infusions of dexmedetomidine and a peripheral α2-adrenoceptor antagonist, MK-467, on sevoflurane minimum alveolar concentration (MAC) in dogs.Study design
Crossover experimental study.Animals
Six healthy, adult Beagle dogs weighing 12.6 ± 0.9 kg (mean ± standard deviation).Methods
Dogs were anesthetized with sevoflurane in oxygen. After a 60-minute instrumentation and equilibration period, the MAC of sevoflurane was determined in triplicate using the tail clamp technique. PaCO2 and temperature were maintained at 40 ± 5 mmHg (5.3 ± 0.7 kPa) and 38 ± 0.5 ºC, respectively. After baseline MAC determination, dogs were administered two incremental loading and infusion doses of either dexmedetomidine (1.5 μg kg?1 then 1.5 μg kg?1 hour?1 and 4.5 μg kg?1 then 4.5 μg kg?1 hour?1) or MK-467 (90 μg kg?1 then 90 μg kg?1 hour?1 and 180 μg kg?1 then 180 μg kg?1 hour?1); loading doses were administered over 10 minutes. MAC was redetermined in duplicate starting 30 minutes after the start of drug administration at each dose. End-tidal sevoflurane concentrations were corrected for calibration and adjusted to sea level. A repeated-measures analysis was performed and comparisons between doses were conducted using Tukey's method. Statistical significance was considered at p < 0.05.Results
Sevoflurane MAC decreased significantly from 1.86 ± 0.3% to 1.04 ± 0.1% and 0.57 ± 0.1% with incremental doses of dexmedetomidine. Sevoflurane MAC significantly increased with high dose MK-467, from 1.93 ± 0.3% to 2.29 ± 0.5%.Conclusions and clinical relevance
Dexmedetomidine caused a dose-dependent decrease in sevoflurane MAC, whereas MK-467 caused an increase in MAC at the higher infusion dose. Further studies evaluating the combined effects of dexmedetomidine and MK-467 on MAC and cardiovascular function may elucidate potential benefits of the addition of a peripheral α2-adrenergic antagonist to inhalation anesthesia in dogs. 相似文献12.
Nikki J. Kells N.J. Beausoleil M.A. Sutherland R.M. Morrison Craig B. Johnson 《Veterinary anaesthesia and analgesia》2017,44(5):1166-1174
Objective
To evaluate the efficacy of oral meloxicam, topical anaesthetic cream and cautery iron in mitigating acute nociceptive responses of pigs to tail docking.Study design
A prospective, randomized, controlled experimental study.Animals
A total of 40 healthy Large White x Landrace pigs aged 21 ± 1 days, weighing 6.1 ± 0.9 kg.Methods
Pigs were randomly assigned to one of four treatments (n = 10 per treatment): CONTROL: docked using clippers without analgesia; MEL: docked using clippers after administration of oral meloxicam; EMLA: docked using clippers after application of topical anaesthetic cream; and CAUT: docked using a cautery iron without analgesia. Anaesthesia was induced and maintained with halothane in oxygen. Following induction, end-tidal halothane was stabilized at 0.95–1.05% and electroencephalograph (EEG) recording commenced. After 5 minutes of baseline data collection, tail docking was performed and recording continued for a further 10 minutes. The EEG summary variables median frequency (F50), 95% spectral edge frequency (F95) and total power (PTOT) were calculated for the baseline period and for consecutive 30-second intervals following docking.Results
Following docking, F50 increased and PTOT decreased significantly in CONTROL and MEL pigs. EMLA pigs exhibited no change in any variable, whilst CAUT pigs exhibited a reduction in PTOT but no change in F50. F50 was higher in control pigs than in EMLA pigs 30–60 seconds after docking (p ≤ 0.01). PTOT was lower in CONTROL than in EMLA pigs 30–90 seconds after docking (p < 0.03) and in CAUT pigs 60 seconds after docking (p = 0.01).Conclusions and clinical relevance
Prior application of EMLA cream abolished EEG indicators of nociception in pigs docked using clippers. Docking using a cautery iron without analgesia ameliorated EEG indicators of nociception, relative to using clippers without analgesia. Prior administration of EMLA cream or the use of cautery instead of clippers may reduce the acute pain experienced by pigs undergoing tail docking. 相似文献13.
14.
Setefilla Quirós-Carmona Rocío Navarrete Juan M. Domínguez María del Mar Granados Rafael J. Gómez-Villamandos Pilar Muñoz-Rascón Daniel Aguilar Francisco J. Funes Juan Morgaz 《Veterinary anaesthesia and analgesia》2017,44(2):228-236
Objective
To determine the effects of two dexmedetomidine continuous rate infusions on the minimum infusion rate of alfaxalone for total intravenous anaesthesia (TIVA), and subsequent haemodynamic and recovery effects in Greyhounds undergoing laparoscopic ovariohysterectomy.Study design
Prospective, randomized and blinded clinical study.Animals
Twenty-four female Greyhounds.Methods
Dogs were premedicated with dexmedetomidine 3 μg kg?1 and methadone 0.3 mg kg?1 intramuscularly. Anaesthesia was induced with IV alfaxalone to effect and maintained with a TIVA mixture of alfaxalone in combination with two different doses of dexmedetomidine (0.5 μg kg?1 hour?1 or 1 μg kg?1 hour?1; groups DEX0.5 and DEX1, respectively). The alfaxalone starting dose rate was 0.07 mg kg?1 minute?1 and was adjusted (± 0.02 mg kg?1 minute?1) every 5 minutes to maintain a suitable depth of anaesthesia. A rescue alfaxalone bolus (0.5 mg kg?1 IV) was administered if dogs moved or swallowed. The number of rescue boluses was recorded. Heart rate, arterial blood pressure and arterial blood gas were monitored. Qualities of sedation, induction and recovery were scored. Differences between groups were tested for statistical significance using a Student’s t test or Mann–Whitney U test as appropriate.Results
There were no differences between groups in sedation, induction and recovery quality, the median (range) induction dose of alfaxalone [DEX0.5: 2.2 (1.9–2.5) mg kg?1; DEX1: 1.8 (1.2–2.9) mg kg?1], total dose of alfaxalone rescue boluses [DEX0.5: 21.0 (12.5–38.8) mg; DEX1: 22.5 (15.5–30.6) mg] or rate of alfaxalone (DEX0.5: 0.12 ± 0.04 mg kg?1 minute?1; DEX1: 0.12 ± 0.03 mg kg?1 minute?1).Conclusions and clinical relevance
Co-administration of dexmedetomidine 1 μg kg?1 hour?1 failed to reduce the dose rate of alfaxalone compared with dexmedetomidine 0.5 μg kg?1 hour?1 in Greyhounds undergoing laparoscopic ovariohysterectomy. The authors recommend an alfaxalone starting dose rate of 0.1 mg kg?1 minute?1. Recovery quality was good in the majority of dogs. 相似文献15.
Tamas D. Ambrisko Johannes Schramel Klaus Hopster Sabine Kästner Yves Moens 《Veterinary anaesthesia and analgesia》2017,44(2):264-272
Objective
To examine changes in the distribution of ventilation and regional lung compliances in anaesthetized horses during the alveolar recruitment manoeuvre (ARM).Study design
Experimental study in which a series of treatments were administered in a fixed order on one occasion.Animals
Five adult Warmblood horses.Methods
Animals were anaesthetized (xylazine, midazolam–ketamine, isoflurane), placed in dorsal recumbency and ventilated with 100% oxygen using peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) of 20 cmH2O and 0 cmH2O, respectively. Thoracic electrical impedance tomography (EIT), spirometry and routine anaesthesia monitoring were performed. At 90 minutes after induction of anaesthesia, PIP and PEEP were increased in steps of 5 cmH2O to 50 cmH2O and 30 cmH2O, respectively, and then decreased to baseline values. Each step lasted 10 minutes. Data were recorded and functional EIT images were created using three breaths at the end of each step. Arterial blood samples were analysed. Values for left-to-right and sternal-to-dorsal centre of ventilation (COV), lung compliances and Bohr dead space were calculated.Results
Distribution of ventilation drifted leftward and dorsally during recruitment. Mean ± standard deviation (SD) values at baseline and highest airway pressures, respectively, were 49.9 ± 0.7% and 48.0 ± 0.6% for left-to-right COV (p = 0.009), and 46.3 ± 2.0% and 54.6 ± 2.0% for sternal-to-dorsal COV (p = 0.0001). Compliance of dependent lung regions and PaO2 increased, whereas compliance of non-dependent lung regions decreased during ARM and then returned to baseline (p < 0.001). Bohr dead space decreased after ARM (p = 0.007). Interestingly, PaO2 correlated to the compliance of the dependent lung (r2 = 0.71, p < 0.001).Conclusions and clinical relevance
The proportion of tidal volume distributed to dependent and left lung regions increased during ARM, presumably as a result of opening atelectasis. Monitoring compliance of the dependent lung with EIT may substitute PaO2 measurements during ARM to identify an optimal PEEP. 相似文献16.
Caroline S. Monk Dennis E. Brooks Tiffany Granone Fernando L. Garcia-Pereira Alexander Melesko Caryn E. Plummer 《Veterinary anaesthesia and analgesia》2017,44(3):502-508
Objective
To measure intraocular pressure (IOP) in horses during hoisting after induction of anesthesia.Study design
Prospective nonrandomized clinical study.Animals
Eighteen healthy adult horses aged [mean ± standard deviation (SD)] 10 ± 4.2 years and weighing 491 ± 110 kg anesthetized for elective procedures.Methods
IOP was measured in the superior eye of each horse based on planned recumbency after induction of anesthesia. Measurements were taken directly after premedication with xylazine or detomidine with butorphanol, after induction with diazepam–ketamine, after intubation, when suspended by the hoist and on the operating table. During hoisting, the head was supported and the eye–heart height was measured to account for variations in head positioning among patients. IOPs were compared across time points using repeated-measures analysis of variance. Regression was used to compare IOP outcome with potential cofactors.Results
Compared with measurements after premedication (17.5 ± 2.5 mmHg) (mean ± SD), hoisting significantly increased IOP (32.4 ± 15.3 mmHg) (p < 0.01). The highest recorded IOP in the hoist was 80.0 (range, 16.0–80.0) mmHg. The difference in IOP between premedication and hoisting was 15.0 ± 16.2 (range, –1.0 to 68.0) mmHg. Body weight had a significant effect on absolute IOP and change in IOP in the hoist (p < 0.01).Conclusions and clinical relevance
Hoist IOP was significantly higher than post-premedication IOP with heavier horses having higher hoist IOPs and greater increases in IOP. The clinician should take this relationship into account when anesthetizing and hoisting larger horses where an increase in IOP could be detrimental. 相似文献17.
Nikki J. Kells Ngaio J. Beausoleil J. Paul Chambers Mhairi A. Sutherland Rebecca S. Morrison Craig B. Johnson 《Veterinary anaesthesia and analgesia》2017,44(5):1156-1165
Objective
To compare electroencephalographic (EEG) responses of pigs to tail docking using clippers or cautery iron, performed at 2 or 20 days of age.Study design
Prospective, randomised controlled experimental study.Animals
A total of 40 Large White x Landrace entire male pigs aged 2 (n = 20) or 20 (n = 20) days were randomly assigned to undergo tail docking using clippers or cautery iron.Methods
Anaesthesia was induced and maintained with halothane delivered in oxygen. Following instrumentation, end-tidal halothane concentration was stabilised at 1.0 ± 0.05%, and EEG recording commenced. After a 5 minute baseline period, tail docking was performed and recording continued for additional 10 minutes. EEG data were subjected to Fast Fourier transformation, yielding the summary variables median frequency (F50), 95% spectral edge frequency (F95) and total power (PTOT). Variables recorded during the baseline period were compared with those calculated at consecutive 15 second intervals following tail docking.Results
Following tail docking, F50 decreased briefly but significantly in 2-day-olds, whereas 20-day-olds exhibited a sustained increase in F50 (p < 0.05). Immediately after tail docking, F50 was overall lower in 2-day-olds than in 20-day-olds (p < 0.05). F95 increased after docking in 20-day-olds docked using clippers (p < 0.05) but did not change in 20-day-olds docked using cautery iron or in 2-day-olds docked using either method. Overall, F95 was lower in 2-day-olds than in 20-day-olds from 30 to 60 seconds after docking (p < 0.05). PTOT decreased after docking in 20-day-olds (p < 0.05) but did not change in 2-day-olds. Overall, PTOT was lower in 2- than in 20-day-olds during baseline and after tail docking (p < 0.05).Conclusions and clinical relevance
These data suggest that tail docking using clippers is more acutely painful than docking using cautery iron and that docking within the first days of birth may be less acutely painful than docking at a later age. 相似文献18.
Sandra Wenger Désirée Müllhaupt Stefanie Ohlerth Sarah Prasse Karina Klein Bianca da Silva Valente Martina Mosing 《Veterinary anaesthesia and analgesia》2017,44(3):529-537
Objective
To compare airway management during induction of anaesthesia, spontaneous ventilation (SV) and controlled mechanical ventilation (CMV), using an endotracheal tube (ETT), laryngeal mask (LM), rabbit-specific supraglottic airway device (v-gel) or facemask (FM).Study design
Prospective randomized crossover experiment.Animals
Ten New Zealand White rabbits.Methods
After premedication, rabbits were randomly allocated to four groups: 1) ETT; 2) LM; 3) v-gel or 4) FM. The required dose of propofol, duration and number of attempts to place an airway device and leakage during SV and CMV at different peak inspiratory pressures (6, 10, 12, 14 and 16 cmH2O) were recorded. Computed tomography (CT) of the head, neck and abdomen were performed before and after CMV.Results
Significantly less propofol and time [2.0 ± 0.5 mg kg?1, 82 ± 34 seconds, p < 0.001] were needed to place the FM compared to the three other groups [v-gel 5.1 ± 2.1 mg kg?1, 302 ± 124 seconds; LM 4.8 ± 1.2 mg kg?1, 275 ± 89 seconds; ETT 5.5 ± 1.4 mg kg?1, 315 ± 147 seconds]. A leak > 25% of the tidal volume occurred at the lowest pressure in FM [median (range), 6 (6–8) cmH2O], which was significantly lower than with v-gel [16 (6–no leak at 16) cmH2O], LM [>16 (6–no leak at 16)] or ETT [>16 (no leak at 16) cmH2O] (p < 0.001). On CT images, the height and width of the larynx were significantly smaller with v-gel in comparison to FM and LM (p = 0.004). A significant increase in the amount of gas in the stomach (p = 0.007), but not gastric volume, was detected in FM and LM.Conclusions and clinical relevance
The v-gel is a practical alternative to LM and ETT for airway management and CMV, but can compress the larynx. The FM is easily placed, but significant leakage occurs during CMV. 相似文献19.
Objective
To characterise, as a clinical study, the pharmacokinetics and pharmacodynamics and describe the hypnotic effect of the neurosteroid alfaxalone (3α-hydroxy-5 α-pregnane-11, 20-dione) formulated with 2-hydroxypropyl-β-cyclodextrin in male and female rats.Study design
Prospective, experimental laboratory study.Animals
A total of 12 (six male and six female) adult, aged-matched Sprague Dawley rats.Methods
Surgery and instrumentation was performed under isoflurane anaesthesia in an oxygen/nitrous oxide mixture (1:2) and local anaesthetic infiltration. All animals received a loading dose (1.67 mg kg?1 minute?1) for 2.5 minutes followed by a constant rate infusion (0.75 mg kg?1 minute?1) for 120 minutes of alfaxalone. Isoflurane and nitrous oxide was discontinued 2.5 minutes after the alfaxalone infusion started. Cardiorespiratory variables (heart rate, respiratory rate, arterial blood pressure and end tidal carbon dioxide tension) and clinical signs of anaesthetic depth were evaluated throughout anaesthesia. Carotid artery blood samples were collected at strategic time points for blood gas analysis, haematology, biochemistry, and plasma concentrations of alfaxalone. Plasma samples were assayed using liquid chromatography-mass spectrometry.Results
There were significant differences between the sexes for plasma clearance (p = 0.0008), half-life (p = 0.0268) and mean residence time (p = 0.027). Mean arterial blood pressure was significantly higher in the male rats (p = 0.0255).Conclusions and clinical relevance
This study confirms that alfaxalone solubilised in 2-hydroxypropyl-β-cyclodextrin provides excellent total intravenous anaesthesia in rats. Sex-based differences in pharmacokinetics and pharmacodynamics were demonstrated and must be considered when designing biomedical research models using alfaxalone. 相似文献20.
Tania E. Perez Katrina L. Mealey Neal S. Burke Tamara L. Grubb Michael H. Court Stephen A. Greene 《Veterinary anaesthesia and analgesia》2017,44(2):370-374