Abstract # 253:

Scheduled for Saturday, June 20, 2015 01:45 PM-02:00 PM: (Cascade E) Oral Presentation


TOTAL BLOOD VOLUME ESTIMATION IN RHESUS MACAQUES (MACACA MULATTA): ARE WE DOING THIS ALL WRONG?

T. R. Hobbs1, S. Blue1, B. Park2, J. Greisel1, M. Conn3 and F. K. Pau1
1Oregon National Primate Res. Ctr., 505 NW 185th Ave, Beaverton, OR 97006, USA, 2Oregon Health and Science University, 3Texas Tech University Health Sciences Center
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     The use of mathematical formulas to regulate blood volume withdrawal in nonhuman primates (NHPs) is ubiquitous among research organizations using NHP models. Blood draw limits are usually expressed as an allowable percentage of total blood volume (TBV) taken over a given time period. TBV is typically calculated using a fixed ratio of blood volume to body weight. These fixed ratios used to estimate TBV vary considerably among research organizations. To help resolve this inconsistency, a study was conducted to determine TBV in each of 20 adult rhesus macaques (10M:10F). Two tracer substances of known volume and concentration were injected simultaneously into the circulatory compartment of each anesthetized subject. The resulting dilutions of these tracers in subject plasma were measured in order to calculate plasma volume. TBV was then calculated from plasma volume and hematocrit. Weight and body composition by dual-energy x-ray absorptiometry were measured and then a body condition score (BCS) was determined for each subject. Our results demonstrated that the commonly used “10%:10% Rule” clearly over-estimated the TBV of all subjects. Moreover, subject body composition has a significant association with TBV not captured by the fixed ratio of blood volume per kg body weight formulas currently in use. We provide an equation that calculates TBV using the variables of weight and BCS, values that are often recorded during routine physical exams.