COMPARISON OF HIGH-DEFINITION OSCILLOMETRIC AND DIRECT ARTERIAL BLOOD PRESSURE MEASUREMENT IN ANESTHETIZED CHEETAHS ( ACINONYX JUBATUS )

EVALUATION OF OSCILLOMETRIC BLOOD PRESSURE MEASUREMENT USING A FINGER CUFF IN ANESTHETIZED CHIMPANZEES (PAN TROGLODYTES)

Cardiovascular disease is common among chimpanzees (Pan troglodytes), and serial blood pressure monitoring in conscious animals may improve disease surveillance and guide hypertension treatment strategies. The objective of this study was to compare the accuracy of a noninvasive, oscillometric blood pressure monitor using a finger blood pressure cuff with invasively measured blood pressure in anesthetized chimpanzees. Twelve chimpanzees were anesthetized with tiletamine-zolazepam intramuscularly, intubated, and maintained on inhaled isoflurane to effect. Blood pressure measurements, which included systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP), were collected simultaneously from an oscillometric blood pressure cuff placed on a forelimb digit (FBP) and a direct arterial catheter (IBP) every 5-10 min while anesthetized. One hundred paired samples were collected, and results were compared using Bland-Altman plots and analysis. FBP showed good agreement with IBP for SAP, MAP, and DAP but consistently overestimated values compared with IBP. FBP may be useful for serial blood pressure monitoring in conscious chimpanzees.

Agreement of high-definition oscillometry at two cuff locations with invasively measured arterial blood pressures in anaesthetised cheetahs

OBJECTIVES

To evaluate the agreement between high-definition oscillometry (HDO) used on the metatarsus or tail base with invasive arterial blood pressures measured in the dorsal pedal artery in anaesthetised cheetahs.

STUDY DESIGN

Prospective clinical study.

ANIMALS

A group of 13 captive adult cheetahs.

METHODS

Cheetahs were immobilised with medetomidine (32-45 μg kg^-1) and tiletamine/zolazepam (0.93-1.39 mg kg^-1) administered intramuscularly, and anaesthesia was maintained with either isoflurane in oxygen or continuous propofol infusion. Invasive blood pressure was measured via a 20 gauge intra-arterial catheter in the dorsal pedal artery in the metatarsus and used as a reference method for pressures simultaneously estimated using HDO on the contralateral metatarsus and tail base. Bland-Altman plots (for repeated measurements) and criteria defined by the American College of Veterinary Internal Medicine (ACVIM) were used to compare agreement according to the anatomical location of the cuff, the anaesthetic maintenance agent and magnitude of the blood pressure.

RESULTS

A total of 147 paired measurements were obtained with HDO on the metatarsus and 135 on the tail. Agreement with invasive pressures was better when HDO was used on the tail (rather than on the metatarsus) with all ACVIM criteria being met. Mean bias (a positive bias meaning that HDO overestimated the invasively measured pressures) ± standard deviation of differences for systolic, diastolic and mean arterial pressures were -7.0 ± 13.9, 4.2 ±12.1 and 4.6 ±11.2 mmHg, respectively, for HDO on the tail, and -11.9 ±15.1, 2.8 ±16.5 and 2.1 ±13.2 mmHg, respectively, for HDO on the metatarsus. Agreement was better during isoflurane anaesthesia than propofol, and at lower blood pressures than at higher.

CONCLUSIONS AND CLINICAL RELEVANCE

When used on the tail base of anaesthetised cheetahs, HDO met the ACVIM validation criteria for a noninvasive device, as compared to invasively measured pressures in the dorsal pedal artery.

Evaluation of the agreement of two oscillometric blood pressure devices with invasive blood pressure in anaesthetized chimpanzees (Pan troglodytes)

OBJECTIVE

To evaluate the agreement of two noninvasive blood pressure devices: a human device with the cuff placed on the wrist (Omron R1) and a veterinary device with the cuff placed on the upper brachium (Surgivet Advisor Vital Signs Monitor) with invasive blood pressure (IBP) measurement in anaesthetized chimpanzees.

STUDY DESIGN

Prospective clinical study.

ANIMALS

A convenience sample of 11 adult chimpanzees undergoing anaesthesia for translocation and routine health checks.

METHODS

Systolic (SAP) and diastolic arterial pressures (DAP) were continuously recorded via a transducer connected to a femoral artery cannula, and at 5 minute intervals from the two oscillometric devices. Agreement was explored using Bland-Altman analysis and bias defined as the mean difference between the two measurement methods. Spearman correlation coefficients were calculated. Significance was set at p < 0.05.

RESULTS

Bias and standard deviation for the Surgivet compared with IBP were 8.6 ± 18 for SAP and 8.4 ± 9.9 for DAP, showing a significant underestimation of both variables. Limits of agreement (LOA) were from -27 to 44 for SAP and from -11 to 28 for DAP. Correlation coefficients between the Surgivet and IBP values were 0.86 for SAP and 0.85 for DAP (p < 0.0001). Bias and standard deviation for the Omron compared with the IBP were -21 ± 25 for SAP and -18 ± 15 for DAP, showing a significant overestimation of both variables. LOA were from -70 to -28 for SAP and from -47 to 11 for DAP. Spearman correlation coefficients between the Omron and IBP values were 0.64 for SAP and 0.72 for DAP (p < 0.0001).

CONCLUSIONS AND CLINICAL RELEVANCE

Although neither device met all the criteria for device validation, the Surgivet presented better agreement with IBP values than the Omron in adult anaesthetized chimpanzees.

Evaluation of butorphanol-azaperone-medetomidine in captive cheetah (Acinonyx jubatus) immobilization

OBJECTIVE

The butorphanol-azaperone-medetomidine fixed-dose combination (BAM, respectively, 30-12-12 mg mL^-1) with subsequent antagonism by naltrexone-atipamezole was evaluated for reversible immobilization of captive cheetahs (Acinonyx jubatus).

STUDY DESIGN

Prospective, clinical trial.

ANIMALS

Twelve cheetahs (six males and six females, weighing 37-57 kg) housed in enclosures, were immobilized at Hoedspruit Endangered Species Centre in the Republic of South Africa.

METHODS

BAM volume dose rate was 0.009-0.014 mL kg^-1 (mean ± standard deviation 0.010 ± 0.001 mL kg^-1). Total dose in all animals was 0.5 mL. The actual doses were as follows: butorphanol (0.29 ± 0.04 mg kg^-1), azaperone (0.12 ± 0.01 mg kg^-1) and medetomidine (0.12 ± 0.01 mg kg^-1). Physiologic variables and quality of immobilization were recorded every 5 minutes beginning at 15-20 minutes after darting. Arterial blood samples were collected three times at 20, 30 and 40 minutes after darting from all animals for analysis of blood oxygenation and acid-base status.

RESULTS

The inductions were calm and smooth and mean induction time was 4.0 ± 1.1 minutes. Heart rate (50 ± 9 beats minute^-1) and respiratory frequency (20 ± 3 breaths minute^-1) were stable throughout immobilization. The recovery time after reversing with naltrexone and atipamezole was 9.1 ± 3.6 minutes.

CONCLUSIONS

and clinical relevance BAM proved to be a reliable and cardiovascular stable drug combination for immobilization of cheetahs.

CARDIORESPIRATORY EFFECTS OF DEXMEDETOMIDINE-BUTORPHANOL-MIDAZOLAM (DBM): A FULLY REVERSIBLE ANESTHETIC PROTOCOL IN CAPTIVE AND SEMI-FREE-RANGING CHEETAHS (ACINONYX JUBATUS)

Multiple anesthesia protocols have been used in the cheetah ( Acinonyx jubatus ). Twenty healthy, captive cheetahs were immobilized with dexmedetomidine (15.8 ± 1.9 μg/kg), butorphanol (0.22 ± 0.03 mg/kg), and midazolam (0.18 ± 0.03 mg/kg) by intramuscular injection. Induction, recumbency, and recovery times were recorded, and physiologic parameters were monitored. Anesthesia was antagonized with atipamezole (0.125 ± 0.02 mg/kg) and naltrexone (0.1 ± 0.014 mg/kg) intramuscularly. All cheetahs were safely anesthetized with this protocol. Cheetahs were laterally recumbent by 8 ± 3.5 min. Cardiorespiratory values were stable throughout the length of anesthesia. Moderate hypertension, with systolic blood pressure ranging from 178 ± 19.8 mm Hg, was initially observed but decreased over time. There was a statistical decreasing trend in temperature; SpO2; and systolic, mean, and diastolic blood pressure, but not in heart rate and end-tidal CO₂. Recoveries were rapid, with cheetahs standing by 11.3 ± 5.7 min postreversal administration. This is the first report of a dexmedetomidine-butorphanol-midazolam anesthetic combination in cheetahs. Overall, this anesthetic protocol proved to be safe and effective.