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Critical Care

Open Access

Effects of peripheral vasodilation induced by regional anaesthesia blocks on resting tissue oxygenation values

  • A Lima1,
  • E Galvin1,
  • J Van Bommel1 and
  • J Bakker1
Critical Care200913(Suppl 1):P237

Published: 13 March 2009


Adult PatientEmergency MedicineNerve FiberLocal AnestheticSympathetic Nerve


Near-infrared spectroscopy is a technique for continuous, noninvasive, bedside monitoring of tissue oxygenation (StO2). The nature of the relationship between the kinetics of StO2 and changes in peripheral circulation has not been investigated. After successful regional anaesthesia blocks, local vasodilation and increased local blood flow occur as a result of blockade of sympathetic nerve fibers. We therefore studied the effects of peripheral vasodilation induced by regional anaesthesia blocks on resting StO2 values.


We recruited healthy adult patients (n = 8) scheduled for selective upper limb surgery under axillary sympathetic blocks. StO2 was continuously monitored over the thenar of the blocked arm using an InSpectra Model 325 probe (Hutchinson Technology Inc., Hutchinson, MN, USA) from the beginning of the local anesthetic (T0) injection until 30 minutes was elapsed (T30). The contralateral arm was used as a control. Differences between group means were tested by Wilcoxon signed test. P < 0.05 was considered statistically significant.


StO2 values in the blocked arm were significantly higher in all patients after the anaesthesia (Figure 1). T30 versus T0, 94 ± 2 versus 82 ± 3; P = 0.002. StO2 did not increase in the control arm.
Figure 1

Effect of peripheral blood flow variations in StO 2 during regional block.


Peripheral vasodilation increases StO2 in normal conditions.

Authors’ Affiliations

Erasmus MC University Medical Centre Rotterdam, the Netherlands


© Lima et al; licensee BioMed Central Ltd. 2009

This article is published under license to BioMed Central Ltd.