Is there a relationship between the hematocrit-to-viscosity ratio and microvascular oxygenation in brain and muscle?

Xavier Waltz, Marie Dominique Hardy-Dessources, Nathalie Lemonne, Danièle Mougenel, Marie Laure Lalanne-Mistrih, Yann Lamarre, Vanessa Tarer, Benoit Tressières, Maryse Etienne-Julan, Olivier Hue, Philippe Connes

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


The hematocrit-to-viscosity ratio (HVR) has been widely used has an estimate of red blood cell (RBC) oxygen transport effectiveness into the microvasculature or as an oxygen delivery index. However, no study investigated the possibility of HVR to truly reflect RBC oxygen transport effectiveness or to be an oxygen delivery index. We measured blood viscosity at high shear rate (225 s-1), hematocrit, HVR, as well as the microvascular oxyhemoglobin saturation (TOI; tissue oxygen index) by spatial resolved near-infrared spectroscopy (NIRS) at cerebral and muscle levels in three population known to have various degrees of hemorheological abnormalities: healthy subjects (AA), patients with sickle cell SC disease (SC) characterized by moderate anemia and patients with sickle cell anemia (SS) marked by severe anemia. At both the cerebral and muscle level, HVR was positively correlated with TOI (r = 0.28; p = 0.03 and r = 0.38; p = 0.003, at the cerebral and muscle level, respectively). These findings suggest that HVR probably play a key role in blood flow and hemodynamic regulation in the microvasculature, hence modulating the amount of oxygen available for tissues. Nevertheless, the strengths of the associations are weak (R2 < 0.50), suggesting that other determinants modulate microvascular blood flow and oxygenation, such as vascular geometry and vasomotor reserve.

Original languageEnglish (US)
Pages (from-to)37-43
Number of pages7
JournalClinical hemorheology and microcirculation
Issue number1
StatePublished - Jan 1 2015


  • Microvascular oxygenation
  • hemorheology
  • sickle cell syndromes

Fingerprint Dive into the research topics of 'Is there a relationship between the hematocrit-to-viscosity ratio and microvascular oxygenation in brain and muscle?'. Together they form a unique fingerprint.

Cite this