Impact of Phlebotomy Tourniquet Use on Blood Lactate Levels in Acutely Ill Patients

Abstract

Objective: Lactate levels are increasingly used to guide resuscitation efforts. Some surgical literature suggests that tourniquet use during phlebotomy falsely elevates results, although studies in healthy volunteers have not demonstrated this. The purpose of this study was to determine in clinical practice whether tourniquet use during the drawing of a lactate results in significantly altered levels compared to the result of a level drawn without a tourniquet. Methods: A prospective cohort study was carried out on emergency department patients whose clinical presentation led a physician to order a lactate level. Written informed consent was obtained from patients or their proxies. Study lactates were obtained using a tourniquet during the draw sequence of other laboratory studies. Lactate levels for clinical use were drawn per hospital protocol with no tourniquet. The time of lactate measurements and patient demographic information were recorded. Lactate levels for each patient were compared with the Wilcoxon RankSum Test. Results: 40 patients were consented and enrolled. The median clinical lactate level was 1.9 (interquartile range 1.5-2.6), and the median study lactate level was 1.9 (interquartile range 1.4-2.7). There was no difference between paired lactate values (p = 0.95). Conclusions: Tourniquet use appears to have no impact on measured lactate levels. Our findings suggest that current practices at many institutions regarding lactate collection are likely too stringent and should be changed.

Effect of tourniquet time on whole blood point‐of‐care lactate concentration: A healthy human volunteer study

“…Balakrishnan et al was one of the few studies to use acutely ill subjects recruited from the ED. 10 Even with recruiting unwell patients, the median lactate concentration was 1.9 mmol/L (within the normal RR). The study found that tourniquet use appears to have no impact on measured lactate levels, that were collected at a median time of 6-min apart.…”

“…Previous healthy volunteer studies have used varying designs, to look at the effect of a tourniquet on lactate concentrations 9,10,14 . Jones et al .…”

“…Balakrishnan et al . was one of the few studies to use acutely ill subjects recruited from the ED 10 . Even with recruiting unwell patients, the median lactate concentration was 1.9 mmol/L (within the normal RR).…”

“…9 As lactate increases in situations of tissue hypoperfusion, it has been hypothesised that the application of the tourniquet may reduce blood flow to the limb and elevate lactate. 7,10 This theoretical reasoning has shaped common practices with guidelines stating that tourniquets are not • There have been concerns that prolonged application of a tourniquet for blood collection may falsely elevate venous lactate concentrations. • In this volunteer study, despite 15-min of tourniquet application there was no clinically significant elevation in venous blood lactate.…”

“…There have been concerns that prolonged application of a tourniquet for blood collection may falsely elevate lactate concentration 9 . As lactate increases in situations of tissue hypoperfusion, it has been hypothesised that the application of the tourniquet may reduce blood flow to the limb and elevate lactate 7,10 . This theoretical reasoning has shaped common practices with guidelines stating that tourniquets are not recommended for the collection of blood that will have lactate analysed 11 .…”