Evaluation of the oscillometric technique for intermittent non-invasive arterial blood pressure measurement in the anaesthetized pig

Abstract

This study was designed to evaluate the oscillometric technique for intermittent non-invasive measurement of arterial pressure (AP) in the anaesthetized pig. In six pigs under sevoflurane anaesthesia, intermittent (every 2 minutes) oscillometric measurements of AP made at a forelimb (FL), a hindlimb (HL) and the tail base were compared with simultaneous direct AP measurements made at the aortic arch (AA) over a wide pressure range (30 -140 mmHg of mean AP). All oscillometric measurements strongly correlated (Pearson correlation coefficient .0.837, P , 0.001) with direct AP measurements, with those made at the FL exhibiting the highest correlation. On the basis of consistency of difference between oscillometric and AA pressure readings at graded pressure levels, measurements made at the tail base provided reliable prediction of systolic AP, at the FL of diastolic AP and at both the tail base and the FL of mean AP. In conclusion, oscillometric measurements at the FL and the tail base offer reliable prediction of AP in the anaesthetized pig. Intraoperative measurement of arterial pressure (AP) provides useful information for the determination of cardiovascular function adequacy during anaesthesia and the estimation of anaesthesia depth. The pig serves as an excellent model for human cardiovascular research due to similarities in anatomy and physiology with humans. In pig models, intra-arterial AP measurement is currently the method of choice in order to obtain accurate and reliable readings. Arterial access is usually achieved by catheterization of large neck or femoral arteries, such as common carotid and femoral arteries.

Accuracy of an oscillometric blood pressure monitor in anesthetized pigs

“…In a study by Ypsilantis et al., the accuracy of an oscillometric blood pressure device was assessed in inhalant anesthetized pigs. 23 Interestingly, the results obtained in that study showed greater accuracy when the cuff was placed on the thoracic limb. However, the cuff placement on the pelvic limb in that study was proximal to the stifle over the tibia.…”

“…The tail has been shown to provide reliable oscillometric blood pressure readings in awake pigs 30 and a study of anesthetized pigs revealed that the tail provided more accurate readings than the pelvic limb. 23 However, because of the small size of the pigs used in this study, oscillometric measurement of blood pressure via the tail was not possible. Owing to the fact that only one monitor was used, as opposed to several of the same model, and only one cuff design was utilized, it is impossible to conclude with complete confidence that the results obtained in this study would apply to every Waveline Pro monitor and cuff design.…”

Mild to severe controlled hypotension with nicardipine can maintain intraoperative microcirculatory cerebral blood flow and oxygenation in pigs

“…Respiratory parameters were adjusted to maintain peripheral blood oxygen saturation (SpO 2 ) ≥ 97% and PaCO 2 = 35-45mmHg. Intraoperative anesthesia was maintained using sevo urane and the appropriate muscle relaxant, cisatracurium besylate (Jianyou Biochemical Pharmaceutical Co., Ltd, Nanjing, China).A warming blanket was used throughout the experiment and body temperature was monitored to maintain the pigs' body temperature at 38-39℃ [15].After preparation, the pigs were placed in the prone position, the forehead was cleaned and the skin was prepared. Following disinfection, a skin incision was made, and a manual skull drill was used to drill until the dura mater was reached.…”