Accuracy of formulas used to predict post-transfusion packed cell volume rise in anemic dogs

Authors

  • Jacqueline L. Short BVMS,

    Corresponding author
    1. VCA All Care AnimalReferral Center, Fountain Valley, CA
    Current affiliation:
    1. VCA All Care AnimalReferral Center, Fountain Valley, CA
    • From Advanced Critical Care and Internal Medicine (now Dedicated Veterinary Care), Tustin, CA
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  • Shenandoah Diehl DVM, DACVECC,

    1. From Advanced Critical Care and Internal Medicine (now Dedicated Veterinary Care), Tustin, CA
    2. Animal Urgent Care of SouthOrange County, Mission Viejo, CA
    Current affiliation:
    1. Animal Urgent Care of SouthOrange County, Mission Viejo, CA
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  • Ravi Seshadri DVM, DACVECC, DAVBP,

    1. From Advanced Critical Care and Internal Medicine (now Dedicated Veterinary Care), Tustin, CA
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  • Sergi Serrano LV, DACVECC

    1. From Advanced Critical Care and Internal Medicine (now Dedicated Veterinary Care), Tustin, CA
    2. Connecticut Veterinary Center, West Hartford, CT
    Current affiliation:
    1. Connecticut Veterinary Center, West Hartford, CT
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  • The authors declare no conflicts of interest.

Address correspondence and reprint requests to

Dr. Jacqueline L. Short, VCA All Care Animal Referral Center, 18440 Amistad St, Fountain Valley, CA 92708, USA.

Email: shortvet@gmail.com

Abstract

Objective

To assess the accuracy of published formulas used to guide packed red blood cell (pRBC) transfusions in anemic dogs and to compare the predicted rise in packed cell volume (PCV) to the actual post-transfusion rise in PCV.

Design

Prospective observational study from April 2009 through July 2009.

Setting

A small animal emergency and specialty hospital.

Animals

Thirty-one anemic client-owned dogs that received pRBC transfusions for treatment of anemia.

Interventions

None

Measurements

Four formulas were evaluated to determine their predictive ability with respect to rise in PCV following transfusion with pRBC. Post-transfusion rise in PCV were compared to calculated rise in PCV using 4 different formulas. Bias and limits of agreement were investigated using Bland–Altman analyses.

Results

Accuracy of existing formulas to predict rise in PCV following transfusion varied significantly. Formula 1 (volume to be transfused [VT] [mL] = 1 mL × % PCV rise × kg body weight [BW]) overestimated the expected rise in PCV (mean difference, 6.30), while formula 2 (VT [mL] = 2 mL ×% PCV rise × kg BW) underestimated the rise in PCV (mean difference, –3.01). Formula 3 (VT [mL] = 90 mL × kg BW × [(desired PCV – Patient PCV)/PCV of donor blood]) and formula 4 (VT [mL] = 1.5 mL ×% PCV rise × kg BW) performed well (mean difference 0.23 and 0.09, respectively) in predicting rise in PCV following pRBC transfusion.

Conclusions

Agreement between 2 formulas, “VT (mL) = kg BW × blood volume (90 mL) × [(desired PCV – recipient PCV)/Donor PCV]” and “VT (mL) = 1.5 ×desired rise in PCV × kg BW,” was found when they were compared to the actual rise in PCV following pRBC transfusion in anemic dogs. Further research is warranted to determine whether these formulas perform similarly well for other species.

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