Association between venous blood lactate levels and differences in quantitative capillary refill time

Abstract

AimCapillary refill time has been widely adopted for clinical assessment of the circulatory status of patients in emergency settings. We previously introduced quantitative capillary refill time and found a positive association between longer quantitative capillary refill time and higher lactate levels in the intensive care units, but not in the emergency department. In this study, we aimed to identify a quantitative and clinically applicable index of circulatory status (ΔA b) that can be measured with quantitative capillary refill time, then evaluated the linear association between this index and lactate levels in the emergency department.MethodsWe undertook a prospective single‐center observational study at a university hospital from November 2015 to July 2016. We included 139 patients with endogenous diseases to test the association between quantitative capillary refill time, ΔA b (measured with a pulse oximeter), and lactate levels.ResultsΔA b was independently and significantly associated with high lactate levels (odds ratio [95% confidence interval]: 0.16 [0.05–0.45]).ConclusionsWe introduced ΔA b, measured using quantitative capillary refill time, as a surrogate index of lactate levels to overcome the shortcomings of capillary refill time. We showed that ΔA b is a feasible, non‐invasive, and rapid assessment of patients with high lactate levels in emergency primary care settings. Future multicenter studies with a longitudinal design should be undertaken to verify our findings.

Pulse oximetry-based capillary refilling evaluation predicts postoperative outcomes in liver transplantation: a prospective observational cohort study

“…Measurements of Q-CRT and ΔA b were performed based on the principle of pulse oximetry. The measurement principle and device wearing method are described in detail, in our previous report [12]. Briefly, transmitted light quantity was measured by a pulse oximeter (OLV-3100, Nihon Kohden Corporation, Tokyo, Japan) equipped with an SpO 2 sensor.…”

“…The quantity of light dimmed by blood only defines the ΔA b (delta A b ), which is the difference between the quantity of light dimmed under infrared light and that dimmed under red light. In short, ΔA b can be determined by oxidized hemoglobin levels (oxygen saturation), hemoglobin concentration, and tissue thickness with blood flow (peripheral circulation blood volume) [12].…”

“…Although CRT may be affected by inter-examiner differences [9,10], a recently developed device can measure CRT quantitatively by using a pulse oximeter [11]. Our recent validation studies discovered a significant correlation between venous blood lactate levels and quantitative CRT (Q-CRT), as measured via the pulse oximeter-based device, in a cohort of ICU patients and emergency department (ED) patients [11,12]. Q-CRT in 23 ICU patients was demonstrated to be statistically correlated with lactate levels (Spearman's rank correlation coefficient, 0.681; p < 0.001) [11].…”

“…In addition to Q-CRT, we developed the delta A b (ΔA b ) measure, which is based on the amount of light absorbed into finger tissue and blood flow by subtracting the light quantity input value from the output value. ΔA b is assumed to reflect overall peripheral oxygen delivery and integrates blood flow, oxygenation, and hemoglobin concentration [12].…”

Can Peripheral Venous Lactate Levels Substitute for Arterial Lactate Levels in The Emergency Department? An Observational Study

“…The current study was a secondary analysis of data from a retrospective observational study that was performed to examine the relationship between quantitative capillary re ll time (Q-CRT) and lactate in patients in the ED [20,21]. In the current study, we examined patients who had undergone arterial and venous blood gas analyses at the time of initial examination.…”