Agreement between oscillometric and direct blood pressure measurements in anesthetized captive chimpanzees (Pan troglodytes)

Abstract

OBJECTIVE To evaluate the level of agreement (LOA) between direct and oscillometric blood pressure (BP) measurements and the ability of oscillometric measurements to accurately detect hypotension in anesthetized chimpanzees (Pan troglodytes). ANIMALS 8 captive, adult chimpanzees. PROCEDURES During prescheduled annual examinations, each chimpanzee underwent general anesthesia and patient monitoring for their examination, echocardiography for a concurrent study, and measurement of direct BP with the use of tibial artery catheterization and oscillometry with the use of a cuff placed around a brachium and a cuff placed around the second digit of the contralateral forelimb for the present study. Bland-Altman plots were generated to compare results for direct and oscillometric BP measurements. Mean bias and 95% LOAs were calculated for oscillometric measurements of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) for each cuff site. Sensitivity and specificity in detecting hypotension were also determined for each cuff site. RESULTS There were 74 paired direct and brachial oscillometric measurements of each, SAP, MAP, and DAP and 66 paired direct and digit oscillometric measurements of each, SAP, MAP, and DAP. Only brachial oscillometric measurements of MAP had adequate sensitivity (78%) and specificity (95%) to accurately detect hypotension, and this technique also had the least mean bias (0.8 mm Hg; 95% LOA, –29 to 31 mm Hg). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that brachial oscillometric measurement of MAP provided reasonable agreement with tibial arterial direct MAP measurement and performed well in diagnosing hypotension in anesthetized chimpanzees.

Arterial Catheterization in Great Apes

“…4 In chimpanzees (Pan troglodytes), for example, the level of agreement between brachial oscillometric systolic and diastolic readings and all oscillometric readings from a forelimb digit was insufficient in detecting hypotension. 16 Another study investigating two different oscillometric blood pressure machines compared with a chimpanzee's femoral invasive blood pressure had similar results, with the oscillometric devices failing to meet the American College of Veterinary Internal Medicine recommended criteria for machine validation. 8 Additionally, arterial blood-gas analysis is the only way to measure the partial pressure of arterial oxygen and the arterial hemoglobin saturation with oxygen.…”