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Remote ischaemic conditioning decreases blood flow and improves oxygen extraction in patients with early complex regional pain syndrome
Author(s) -
Hegelmaier T.,
Kumowski N.,
Mainka T.,
Vollert J.,
Goertz O.,
Lehnhardt M.,
Zahn P.K.,
Maier C.,
Kolbenschlag J.
Publication year - 2017
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/ejp.1033
Subject(s) - complex regional pain syndrome , blood flow , perfusion , medicine , tourniquet , anesthesia , laser doppler velocimetry , ischemia , microcirculation , hemodynamics , oxygen saturation , oxygenation , hypoxia (environmental) , cardiology , oxygen , chemistry , organic chemistry
Background Remote ischaemic conditioning ( RIC ) is the cyclic application of non‐damaging ischaemia leading to an increased tissue perfusion, among others triggered by NO (monoxide). Complex regional pain syndrome ( CRPS ) is known to have vascular alterations such as increased blood shunting and decreased NO blood‐levels, which in turn lead to decreased tissue perfusion. We therefore hypothesized that RIC could improve tissue perfusion in CRPS . Method In this proof‐of‐concept study, RIC was applied in the following groups: in 21 patients with early CRPS with a clinical history less than a year, in 20 age/sex‐matched controls and in 12 patients with unilateral nerve lesions via a tourniquet on the unaffected/non‐dominant upper limb. Blood flow and tissue oxygen saturation (StO 2 ) were assessed before, during and after RIC via laser Doppler and tissue spectroscopy on the affected extremity. The oxygen extraction fraction was calculated. Results After RIC , blood flow declined in CRPS ( p < 0.01). StO 2 decreased in CRPS and healthy controls ( p < 0.01). Only in CRPS , the oxygen extraction fraction correlated negatively with the decreasing blood flow ( p < 0.05). Conclusion Contrary to our expectations, RIC induced a decrease of blood flow in CRPS , which led to a revised hypothesis: the decrease of blood flow might be due to an anti‐inflammatory effect that attenuates vascular disturbances and reduces blood shunting, thus improving oxygen extraction. Further studies could determine whether a repeated application of RIC leads to a reduced hypoxia in chronic CRPS . Significance Remote ischaemic conditioning leads to a decrease of blood flow. This decrease inversely correlates with the oxygen extraction in patients with CRPS .