Isoflurane MAC determination in dogs using three intensities of constant-current electrical stimulation

Figueiro, M. R.; Soares, Jorge; Ascoli, F. O.; Werre, Stephen R.; Segura, Ignacio A. Gómez de

doi:10.1111/vaa.12341

Cited by 15 publications

(11 citation statements)

References 33 publications

(119 reference statements)

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“…Degree of analgesia was assessed according to a methodology adapted from Figueiró et al (2016), using an electrical stimulator connected to a pair of stainless steel needles spaced by 3cm and subcutaneously inserted into the tail ventral base. Each stimulus was applied by increasing the constant current (in mA) until a positive response was observed.…”

Section: Methodsmentioning

confidence: 99%

“…Analgesia was monitored only as of the beginning of continuous infusion of the TZ combination (form times M5 to M60) considering that electrical stimulation in dogs is an alternative to the supramaximal mechanical noxious stimulation through tail-base clamp (Yamashiro et al 2015). Thus, current intensities ≥30mA are considered supramaximal noxious stimuli for the same anatomical site in the tail (Figueiró et al 2016) Myorelaxation was evaluated based on the degree of extensor rigidity and resistance of the limbs to manipulation and on muscle tone; this parameter was rated as follows: excellent (score 2), when total muscle flaccidity was evident; good (score 1), when moderate maintenance of muscle tone was observed, with occurrence of discrete tremors; poor (score 0), if the animal showed tremors and stiffness, state of catalepsy, or intense movement. The quality of recovery after anesthesia was evaluated according to the following scores: excellent (score 2), when the animal rested quietly, but responsively; good (score 1), when the animal showed moderate excitement; poor (score 0), when it showed agitation, tremors and/or myoclonus (Cardoso et al 2008).…”

Section: Methodsmentioning

confidence: 99%

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Anesthetic quality and cardiovascular and respiratory effects of continuous intravenous infusion of tiletamine-zolazepam in bitches

et al. 2019

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P.I. 2019. Anesthetic quality and cardiovascular and respiratory effects of continuous intravenous infusion of tiletamine-zolazepam in bitches. Pesquisa Veterinária Brasileira 39 (3): [214][215][216][217][218][219][220]. The objective of this study was to evaluate the quality and recovery from anesthesia promoted by the tiletamine-zolazepam (TZ) combination administered intravenously (IV) continuously in bitches pre-medicated with acepromazine. Eight cross-bred, clinically healthy bitches weighing 13.7 ±1.9kg on average were used in this study. After a food fast of 12 h and a water fast of four hours, the animals were treated with acepromazine (0.1mg/kg, intramuscular) and, after 15 minutes, anesthesia was induced with a combination of tiletamine-zolazepam (2mg/kg, IV) immediately followed by continuous IV infusion thereof at a dose of 2mg/kg/h for 60 min. The following parameters were measured in all animals immediately before administration of acepromazine (M15), immediately before anesthetic induction (M0), and at 5, 10, 20, 30, 40, 50, and 60 min after initiation of continuous infusion (M5, M10, M20, M30, M40, M50, and M60): electrocardiography (ECG), heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), body temperature (BT), and arterial hemogasometry, with the last performed only at experimental times M15, M0, M30, and M60. A subcutaneous electrical stimulator was used to evaluate the degree of analgesia. Myorelaxation and quality of anesthetic recovery were also assessed, classifying these parameters as excellent, good, and poor. Anesthetic recovery time was recorded in minutes. HR increased significantly at time M10 in relation to that at M-15, and at times M5, M10, M40, and M50 in relation to that at M0. MAP decreased significantly at M20 and M30 compared with the baseline. BT decreased significantly at M50 compared with that at M0, but no hypothermia was observed. RR showed significant reduction at M5, M10, and M20 in relation to that at M-15, and at M5 and M10 in relation to that at M0, and bradypnoea was observed during the first 20 min after anesthetic induction. Significant decreases in the PR interval at times M10, M40, and M50 were observed in relation to that at M15. Amplitude of the R wave showed significant decrease at M20 compared with that at M-15. In the other ECG parameters, no significant difference was observed between the times evaluated. Hemogasometric parameters and analgesia did not show significant alterations. Myorelaxation and quality of anesthetic recovery were considered excellent. Recovery time was 15.1±7.7 min for positioning of sternal decubitus and 45.5±23.1 minutes for return of ambulation. Continuous IV administration of TZ combination does not produce satisfactory analgesia and does not cause severe cardiorespiratory and hemogasometric effects in bitches pre-medicated with acepromazine.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Anesthetic quality and cardiovascular and respiratory effects of continuous intravenous infusion of tiletamine-zolazepam in bitches

et al. 2019

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“…Isoflurane MAC was determined following a bracketing technique by using a square-wave electrical noxious stimulus of 30 mA and 50 Hz applied to the cranial aspect of the tarsus by two stainless steel needles subcutaneously positioned approximately 3 cm apart [ 26 ]. This noxious stimulation was sustained for 60 seconds or until a positive response was observed.…”

Section: Methodsmentioning

confidence: 99%

Cardiovascular and respiratory effects of lumbosacral epidural bupivacaine in isoflurane-anesthetized dogs: The effects of two volumes of 0.25% solution

et al. 2018

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The purpose of this study was to compare cardiovascular and respiratory effects of two volumes of bupivacaine 0.25% (0.2 mL kg-1—treatment BUP02—and 0.4 mL kg-1 –treatment BUP04) administered epidurally at the lumbosacral intervertebral space in dogs anesthetized with isoflurane. This experimental prospective randomized crossover design trial used six mixed breed adult dogs, four neutered males and two spayed females. Each dog was anesthetized on three different occasions: the first for isoflurane minimum alveolar concentration (MAC) measurement, and the following two assigned treatments (BUP02 or BUP04). On the two treatment days, anesthesia was induced and maintained with isoflurane at 1.3 MAC during the experiments. Cardiovascular and respiratory measurements were recorded before (T0) and 5, 15, 30, 60 and 90 minutes after the epidural administration of bupivacaine. Comparisons between and within groups were performed by a mixed-model ANOVA and Friedman’s test when appropriate followed by Bonferroni post-hoc test or Dunnet’s test to compare time points within each treatment with T0 (p < 0.05). Mean arterial pressure decreased significantly from 15 to 90 minutes after the administration of BUP02 and from 5 to 60 minutes in BUP04, with lower values in BUP04 than in BUP02 lasting up to 30 minutes after bupivacaine administration. No significant changes in cardiac output and systemic vascular resistance were observed in either treatment. Hypoventilation was only detected in BUP04. Hemoglobin concentration and arterial oxygen content decreased after both treatment of bupivacaine with no significant decrease in oxygen delivery. Two dogs in BUP04 developed Horner’s syndrome. The epidural administration of 0.4 mL.kg-1 of bupivacaine to dogs in sternal recumbency anesthetized with isoflurane 1.3 MAC caused more cardiovascular and respiratory depression than 0.2 mL.kg-1.

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“…Surgical planes of anesthesia are usually at 1.2 to 1.4 times the MAC, which are close to 1.69% of isoflurane in dogs (Figueiró et al, 2016). Vettorato et al (2010) have observed values between 1.3 and 1.4% (approximately 1 MAC) at the start of surgery with tramadol analgesia, corroborating another study reporting lower ET´I SO after tramadol analgesia in dogs (Mastrocinque and Fantoni, 2003).…”

Section: Discussionmentioning

confidence: 63%

Different rates of tramadol infusion for peri and postoperative analgesia in dogs undergoing orthopedic surgery

Oliva

Albuquerque

Floriano

et al. 2019

Arq. Bras. Med. Vet. Zootec.

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The study aimed to determine the continuous rate infusion of tramadol associated with peri- and postoperative analgesia for orthopedic surgeries in dogs, as well as cardiorespiratory and adverse effects. Thirty dogs aged 4.2±1.2 years and weighing 15.1±0.9kg were enrolled in the study, premedicated intramuscularly with acepromazine (0.04mg kg-1) and tramadol (2mg kg-1); anesthesia was induced with propofol and maintained with isoflurane in oxygen. Three infusion rates were compared, comprising three experimental groups: G2: 2.0mg kg-1 h-1; G2.5: 2.5mg kg-1 h-1; and G3: 3.0mg kg-1 h-1. Surgery was initiated 15 minutes following the start of tramadol infusion. During anesthesia, animals were monitored in predefined time points: immediately after tracheal intubation and start of inhalation anesthesia (T0); surgical incision (TSI); final suture (TFS) and end of tramadol infusion (TEI), which was maintained for at least 120 minutes and prolonged according to the duration of surgery. Postoperative analgesia was evaluated through an interval pain scoring scale and the Melbourne pain scale. The mean time of tramadol infusion was greater than 120 minutes in all groups and no differences were found among them (141±27 minutes in G2, 137±27 minutes in G2.5 and 137±30 minutes in G3). Perioperative analgesia was regarded as short and did not correlate with infusion rates. Tramadol infusion provided adequate analgesia with cardiorespiratory stability Analgesia was not dose-dependent, however, and residual postoperative effects were short-lasting, which warrants proper postoperative analgesia following tramadol infusion. Additional studies are required using higher infusion rates and standardized nociceptive stimulation in order to determine how doses influence tramadol analgesia and whe therthereis a limit to its effect in dogs.

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Isoflurane MAC determination in dogs using three intensities of constant-current electrical stimulation

Cited by 15 publications

References 33 publications

Anesthetic quality and cardiovascular and respiratory effects of continuous intravenous infusion of tiletamine-zolazepam in bitches

Anesthetic quality and cardiovascular and respiratory effects of continuous intravenous infusion of tiletamine-zolazepam in bitches

Cardiovascular and respiratory effects of lumbosacral epidural bupivacaine in isoflurane-anesthetized dogs: The effects of two volumes of 0.25% solution

Different rates of tramadol infusion for peri and postoperative analgesia in dogs undergoing orthopedic surgery

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