Abstracts of Reports and Presentations
Concerning the BVA-100

 
     
 
Maimonides Medical Center
Department of Anesthesiology
Brooklyn, NY

GENDER DIFFERENCE IN BLOOD VOLUME IN PATIENTS
UNDERGOING CABG SURGERY

Mamatha Punjala, Chiedozie Udeh, Murali Pagala, Changa Tyagaraj, Abdelhamid Elfaham, Ketan Shevde

Presented at the Post Graduate Assembly in Anesthesiology in New York, Dec. 11-15


Abstract: Females require more blood transfusion than males during coronary artery bypass graft (CABG) surgery. Recently we have shown that this gender difference is due to a combined effect of age, body surface area (BSA), hematocrit, and duration of surgery (Keshikar et al., 1999). This ongoing study was undertaken to assess whether differences in blood volume (BV), R13C volume (RV), and plasma volume (PV) also contribute to gender difference. Volumes of blood components. were determined using a BVA-100 blood volume analyzer (DAXOR, Corporation). For 9 males, the mean BV was 4329 197, RV 1506 70, and PV 2670 106. Whereas for 5 females, the respective values were lower by 12% (P<0.009), 34% (P<0.001), and 11% (P>0.05). When these values, were corrected for BSA, the RV was lower by 25% (P<0.001) in females than in males. These results indicate that lower RBC mass in females is a significant factor in determining their greater requirement for blood transfusion.

Aim: Determine whether male and female CABG patients have different volumes of total blood, RBCs and plasma.

Study Patients: This prospective study involved 34 consenting CABG patients: 21 males and 13 females. Patients with multiple procedures or reoperations were excluded.

Methods: Each patient received intravenously 1 ml of Albumin containing 25 C of I-131. Five ml blood samples were collected before, and 12, 17, 22, 30, and 35 min after the injection One ml serum samples were loaded into DAXOR BVA-100 Blood Volume Analyzer. Based on radioactivity in samples and standard, the volumes of total blood, RBCs, and plasma were determined for each patient.

Results:

  Males Females
Age (years) 68.1 1.9 68.9 2.4
Weight (kg) 80.2 2.5 71.2 3.8*
BSA (sqm) 1.98 0.04 1.76 0.05
Preopt HCT (%) 38.1 1.3 33.4 0.8*

*P <0.05

Females have significantly lower volumes of total blood, RBCs, and plasma than males.

Even when the values were expressed per unit BSA, females still had significantly lower volumes of total blood and RBCs.

Conclusion: Lower blood and RBC volumes in females may account for their greater need for transfusion compared to male CABG patients.

Reference: Kashikar A., et al. Anethesiology 89:A245, 1998.