Skin microcirculatory reactivity assessed using a thermal challenge is decreased in patients with circulatory shock and associated with outcome

Abstract

BackgroundShock states are characterized by impaired tissue perfusion and microcirculatory alterations, which are directly related to outcome. Skin perfusion can be noninvasively evaluated using skin laser Doppler (SLD), which, when coupled with a local thermal challenge, may provide a measure of microcirculatory reactivity. We hypothesized that this microvascular reactivity would be impaired in patients with circulatory shock and would be a marker of severity.MethodsWe first evaluated skin blood flow (SBF) using SLD on the forearm and on the palm in 18 healthy volunteers to select the site with maximal response. Measurements were taken at 37 °C (baseline) and repeated at 43 °C. The 43 °C/37 °C SBF ratio was calculated as a measure of microvascular reactivity. We then evaluated the SBF in 29 patients with circulatory shock admitted to a 35-bed department of intensive care and in a confirmatory cohort of 35 patients with circulatory shock.ResultsIn the volunteers, baseline SBF was higher in the hand than in the forearm, but the SBF ratio was lower (11.2 [9.4–13.4] vs. 2.0 [1.7–2.6], p < 0.01) so we used the forearm for our patients. Baseline forearm SBF was similar in patients with shock and healthy volunteers, but the SBF ratio was markedly lower in the patients (2.6 [2.0–3.6] vs. 11.2 [9.4–13.4], p < 0.01). Shock survivors had a higher SBF ratio than non-survivors (3.2 [2.2–6.2] vs. 2.3 [1.7–2.8], p < 0.01). These results were confirmed in the second cohort of 35 patients. In multivariable analysis, the APACHE II score and the SBF ratio were independently associated with mortality.ConclusionsMicrocirculatory reactivity is decreased in patients with circulatory shock and has prognostic value. This simple, noninvasive test could help in monitoring the peripheral microcirculation in acutely ill patients.Electronic supplementary materialThe online version of this article (10.1186/s13613-018-0393-7) contains supplementary material, which is available to authorized users.

Transcutaneous PCO2 monitoring in critically ill patients: update and perspectives

“…This concept of studying the variations of cutaneous capnometry during a heating challenge was recently described ( Figure 6) (11). The same paradigm has been used in a recent study by the De Backer team with a laser-Doppler flowmetry device, adding external validity for heat or thermal challenge with TCM (34). Schematically, a crude estimate with no heated electrode (standardized normothermia) together with a functional provocative test (as a thermal or heating challenge) could be useful or informative on peripheral perfusion to evaluate tissue hypercarbia related to low flow states or altered microcirculation with loss of "hemodynamic coherence", as recently conceptualized as occurring during sepsis and "microcirculatory shock" (35).…”

Thermography Quantification of Human Perfusion Thermal Signature

“…The standardized protocol sequence of the BFIRT signature measurement, used for developing excitation response of thermo-regulatory system as a constant and equal to the body core temperature T c [36,45]. As for the local venous blood, it seems reasonable to assume that it equilibrates with the tissue in capillary network and enters the venules at local tissue temperature [30]. The parameters and constants of the Pennes equation used in the simulation as listed in table.…”

“…1). PPG is used widely to measure the pulse waveform [26], pulse wave reflection [27], cutaneous (dermal) perfusion [28], and capillary micro-circulation [29,30]. Recently, several researchers have proposed a series of bioheat and statistical models that in combination with customized highly sensitive thermal imaging hardware can measure various physiological variables at several feet away from the subjects.…”

Monitoring skin blood flow to rapidly identify alterations in tissue perfusion during fluid removal using continuous veno-venous hemofiltration in patients with circulatory shock

“…Skin hypoperfusion occurs before systemic hemodynamic variables worsen [9,[21][22][23] and its persistence has been shown to be associated with higher mortality [24][25][26]. Additionally, a shortening of the prolonged capillary refill time (CRT) during resuscitation suggested resolution of tissue hypoperfusion, as reflected by a reduction in lactate concentration [25,[27][28][29].…”

“…Skin laser Doppler (SLD) is a simple noninvasive tool that has been widely used in clinical studies to evaluate cutaneous microcirculatory perfusion [24,26,30]. SLD measures local microcirculatory blood flow including perfusion in capillaries (nutritive flow), arterioles, venules and shunting vessels [31][32][33].…”