Non-invasive blood haemoglobin and plethysmographic variability index during brachial plexus block
2015 (English)In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 114, no 5, 812-817 p.Article in journal (Refereed) Published
Background Plethysmographic measurement of haemoglobin concentration (SpHb ), pleth variability index (PVI), and perfusion index (PI) with the Radical-7 apparatus is growing in popularity. Previous studies have indicated that SpHb has poor precision, particularly when PI is low. We wanted to study the effects of a sympathetic block on these measurements.
Methods Twenty patients underwent hand surgery under brachial plexus block with one Radical-7 applied to each arm. Measurements were taken up to 20 min after the block had been initiated. Venous blood samples were also drawn from the non-blocked arm.
Results During the last 10 min of the study, SpHb had increased by 8.6%. The PVI decreased by 54%, and PI increased by 188% in the blocked arm (median values). All these changes were statistically significant. In the non-blocked arm, these parameters did not change significantly.
Conclusions Brachial plexus block significantly altered SpHb , PVI, and PI, which indicates that regional nervous control of the arm greatly affects plethysmographic measurements obtained by the Radical-7. After the brachial plexus block, SpHb increased and PVI decreased.
Place, publisher, year, edition, pages
Oxford University Press (OUP): Policy B - Oxford Open Option B , 2015. Vol. 114, no 5, 812-817 p.
haemoglobinometry; nerve blockade; perfusion; photoplethysmography; vasodilation
Anesthesiology and Intensive Care
IdentifiersURN: urn:nbn:se:liu:diva-118861DOI: 10.1093/bja/aeu484ISI: 000354153500015PubMedID: 25603961OAI: oai:DiVA.org:liu-118861DiVA: diva2:817986