Evaluation of indirect blood pressure monitoring in awake and anesthetized red‐tailed hawks (Buteo jamaicensis): effects of cuff size, cuff placement, and monitoring equipment
ABSTRACT Objective To compare Doppler and oscillometric methods of indirect arterial blood pressure (IBP) with direct arterial measurements in anesthetized and awake red-tailed hawks.Study design Prospective, randomized, blinded study.Animals Six, sex unknown, adult red-tailed hawks.Methods Birds were anesthetized and IBP measurements were obtained by oscillometry (IBP-O) and Doppler (IBP-D) on the pectoral and pelvic limbs using three cuffs of different width based on limb circumference: cuff 1 (20–30% of circumference), cuff 2 (30–40%), and cuff 3 (40–50%). Direct arterial pressure measurements were obtained from the contralateral superficial ulnar artery. Indirect blood pressure measurements were compared to direct systolic arterial pressure (SAP) and mean arterial pressure (MAP) during normotension and induced states of hypotension and hypertension. Measurements were also obtained in awake, restrained birds. Three-way anova, linear regression and Bland–Altman analyses were used to evaluate the IBP-D data. Results are reported as mean bias (95% confidence intervals).Results The IBP-O monitor reported errors during 54% of the measurements. Indirect blood pressure Doppler measurements were most accurate with cuff 3 and were comparable to MAP with a bias of 2 (−9, 13 mmHg). However, this cuff consistently underestimated SAP with a bias of 33 (19, 48 mmHg). Variability in the readings within and among birds was high. There was no significant difference between sites of cuff placement. Awake birds had SAP, MAP and diastolic arterial pressure that were 56, 43, and 38 mmHg higher than anesthetized birds.Conclusions and clinical relevance Indirect blood pressure (oscillometric) measurements were unreliable in red-tailed hawks. Indirect blood pressure (Doppler) measurements were closer to MAP measurements than SAP measurements. There was slightly better agreement with the use of cuff 3 on either the pectoral or pelvic limbs. Awake, restrained birds have significantly higher arterial pressures than those under sevoflurane anesthesia.
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ABSTRACT: Although the use of indirect methods for measuring blood pressure has become commonplace in dogs and cats, it is uncertain whether these methods can be extended to avian species with any proven accuracy or precision. To evaluate the precision of indirect blood pressure measurement in conscious psittacine birds by the Doppler flow method, 25 psittacine birds, weighing between 230 and 1263 g and representing 17 commonly kept species, were examined. Birds were manually restrained, and indirect blood pressure measurements were obtained by placing a cuff around the limb proximal to a Doppler ultrasonic flow detector held over either the basilic or cranial tibial artery. Three sets of 3 measurements were obtained from each wing and leg site, with cuff size and site based on pilot study data identifying the selection criteria of cuff placement with the least variance among repeated measurements. A mixed-effects linear regression analysis was performed to evaluate the differences among mean blood pressure measurements in the individual bird, obtained from the wing versus leg site as well as from 3 different cuff placements at each site. Results showed variation attributable to the limb was not significant. However, blood pressure measurements varied significantly between cuff placements on the same limb from the same bird and among individual birds. The precision of these indirect blood pressure measurements was poor. From these results, the meaning and value of Doppler-derived indirect blood pressure measurements obtained in psittacine birds remains in question, warranting further research.Journal of Avian Medicine and Surgery 06/2011; 25(2):83-90. DOI:10.2307/41318121 · 0.67 Impact Factor
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ABSTRACT: To compare isoflurane, sevoflurane and desflurane for inhalant anesthesia in red-tailed hawks (Buteo jamaicensis) in terms of the speed and characteristics of induction; cardiovascular and respiratory parameters while anesthetized; and speed and quality of recovery. Prospective, cross over, randomized experimental study. 12 healthy adult red-tailed hawks. Anesthesia was induced with isoflurane, sevoflurane or desflurane in oxygen via face mask in a crossover, randomized design with a 1 week washout period between each treatment. Hawks were tracheally intubated, allowed to breathe spontaneously, and instrumented for cardiopulmonary monitoring. Data collected included heart rate, respiratory rate, end-tidal CO(2) , inspired and expired agent, SpO(2,) temperature, systolic blood pressure, time to intubation and time to recovery (tracking). Recovery was subjectively scored on a 4 point scale as well as a summary evaluation, by a single blinded observer. No significant difference in time to induction and time to extubation was noted with the administration of isoflurane, sevoflurane or desflurane. Time to the ability of the bird to follow a moving object with its eyes (tracking) was significantly faster with the administration of sevoflurane and desflurane. All recoveries were scored 1 or 2 and were assessed as good to excellent. No significant difference was noted in heart rate, blood pressure and temperature among the three inhalants. Administration of isoflurane resulted in lower respiratory rates. Overall, although isoflurane remains the most common inhaled anesthetic in avian practice, sevoflurane and desflurane both offer faster time to tracking, while similar changes in cardiopulmonary function were observed with each agent during anesthesia of healthy red-tailed hawks.Veterinary Anaesthesia and Analgesia 11/2011; 39(1):29-37. DOI:10.1111/j.1467-2995.2011.00668.x · 1.78 Impact Factor
Article: Anesthesia and Analgesia in Birds[Show abstract] [Hide abstract]
ABSTRACT: Surgical intervention and painful conditions often apply to avian patients that are presented to veterinary hospitals. Therefore, anesthesia and analgesia are an important part of the daily routine associated with avian veterinary practice. These procedures differ from mammal medicine primarily because of different physiologic composition and different anatomical structures, which are described when relevant to anesthetic management. This article describes the most common anesthetic and analgesic procedures for birds and provides recommendations for veterinarians who treat these species. Moreover, there are detailed descriptions of preanesthetic and postanesthetic patient care and how to monitor anesthetized birds. Advantages and disadvantages of the different anesthetic techniques and analgesic protocols are also reviewed. If one treats birds in a veterinary hospital, it is important to have inhalation anesthesia equipment readily available so that it can be used when needed.Journal of Exotic Pet Medicine 01/2012; 21(1):44–58. DOI:10.1053/j.jepm.2011.11.008 · 0.43 Impact Factor