J. Muhling et al., Cerebral blood flow velocity during isovolemic hemodilution and subsequentautologous blood retransfusion, CAN J ANAES, 46(6), 1999, pp. 550-557
Citations number
34
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Journal title
CANADIAN JOURNAL OF ANAESTHESIA-JOURNAL CANADIEN D ANESTHESIE
Purpose: To quantify the influence of hematocrit on cerebral blood flow vel
ocity (CBFV) in healthy volunteers undergoing acute isovolemic hemodilution
(HD) with hydroxyethyl starch 10% (HES) and subsequent autologous whole bl
ood retransfusion (RT).
Methods: In 11 volunteers 20 ml . kg(-1) blood was withdrawn over 30 min an
d simultaneously replaced with HES 10%. Thirty min later, RT was-started at
a constant rate over 30 min. Recorded parameters included: CBFV, pulsatili
ty-index (PI) and resistance-index (RI) of the middle cerebral artery(MCA).
Blood pressure (BP), heart rate (HR), hemoglobin (Hb), hematocrit (Hc) per
ipheral O-2-saturation (SpO(2)), PETCO2, arterial oxygen content (CaO2) and
cerebral arterial O-2-transport (C-E-DO2 = CaO2 x Vm-MCA) were monitored.
Results: An average of 1570 total blood was withdrawn which resulted in a d
ecrease in Hb from 14.5 mg . dl(-1) to 10.3 mg . dl(-1); Hc (and CaO2) decr
eased from 41.8% (19.8 ml . dl(-1)) to 29.6% (14.2 ml . dl(-1); P < 0.01).
Vm-MCA increased from 61.2 cm . sec(-1) to 77.3 cm . sec(-1) (P < 0.01). Fo
llowing RT;Vm-MCA decreased again, but remained higher than baseline (P < 0
.01). PI decreased by 13% following RT(P < 0.05). There were no changes in
RI, HR, BP, SpO(2) and PETCO2. Regression lines could be fitted between He
and Vm-MCA, Vm-MCA and CaO2, and between He and CEDO2.
Conclusions: Transcranial Doppler changes in blood flow velocities correlat
ed with the simultaneously recorded systemic Hc and CaO2 values. We found a
2% increase in CBN for each 1% decrease in Hc and CaO2.