Hello Michael,

I don't have the answer you need. But maybe I can help you to find it.

I suppose you know the papers from Kräuchi K. He showed me some time ago this paper:

Rubinstein EH, Sessler DI. (1990). Skin-surface temperature

gradientes correlate with fingertip blood flow in humans.

Anesthesiology. 73:541–5.

I know that it is not what you need exactly. But perhaps...

Good luck

Antonio

Thank you for the heads up about the Rubinstein report, as well as the Kraeuchi paper. Hopefully those papers can shed some more light on the matter.

Dear Michael - this is an interesting question.

However there are a number of variables which may confound the correlation between skin temperature and venous blood pooling. Are you aware that you can measure heat flux independently using a sensor (; Daniellson (1990) J Appl Physiol 68(3):1275-81; Kurazami (2008) Building and Environment 43, 2142) as well as venous blood pooling using infra red thermography or plethysmography. You could then establish the correlation (or lack of) during different conditions.

It should be remembered that the measurement of heat flux can be unstable and itself be dependent on many factors). This has been discussed in food engineering see Datta AK (2007) Porous media approaches to studying simultaneous heat and mass transfer in food processes. I: Problem formulations. Journal of Food Engineering

Volume 80, Issue 1,80–95

Hope this helps

Yes, there are a great number of variables. The Rubinstein paper measured local temperarture changes in the fingertip during peripheral vasoconstriction. Using this heat flux formula, they determined that yes indeed there was a correlation between the degree of vasoconstriction, and finger tip temperature. As vasoconstricion increases, local blood flow decreases, and local finger tip temperature falls. Now, the problem is, when one measures lets say peripheral thigh or arm temperature, without using NIRS, and one is trying to determine if increased venous pooling in the lower extremities is reflected by a decrease in temperature, does this heat flux formula still apply? Given the mass of fat and fate free mass overlying the vasculature in the thigh and arm, do these temperature increases reflect venous pooling in the great veins, or are they just reflecting local skin blood flow/ or subcutaneous, muscle capillary blood flow? Thanks for the feedback, I will read the rest of the recommended articles in due time. As a side note, the Rubinstein paper controls for these variables as the finger tip is relatively free of subcutaneous fat and muscle. Also it is an anastomosis. I propose that this would lead to good correlations with local constriction and temperature

Maybe these papers about blood pressure masking factors could help you:

Kario et al., 1999

Ambulatory physical activity as a determinant of diurnal blood pressure variation.

They didn't measure skin temperature. However, I think it is a good paper and maybe it helps you.

Blazquez et al., 2012

Wrist skin temperature, motor activity, and body position as determinants of the circadian pattern of blood pressure.

There is a short experiment (acute effects) with body position and wrist skin temperature. The subjects were changing their leg muscles tone according to the inclination degrees.

Kräuchi et al., 2012

Diurnal blood pressure variations are associated with changes in distal-proximal skin temperature gradient.

They can predict blood pressure changes with distal-proximal skin temperature gradient.

I was conducting infrared thermographic imaging of varicose veins and warmed the venous blood by having the subject place their feet in a warm for bath. The venous return called be visualized by thermography using warmed blood as its own contrast medium. Any localized pooling in the peripheral vasculature was easily observed and recorded. Valvular damage and insufficiency was clearly identified.

Yes, but did you happen to measure cutaneous temperature? And if so, where anatomically did you measure it and was there a correlation between venous polling and increases in skin temperature?

Yes, we have looked at Crandalls work, on the influences of external heating and cooling on LBNP. What we have seen though, is that there are skin temperature increases and decreases observed during LBNP and centrifuge. These skin thermistors are normally located on the lower leg, medial thigh, medial arm, and dorsal side of the hand. Preliminary statistical analysis shows that there are strong correlations with skin temperature and TPR, CO, HR, SV, and MAP. However, it still remains to be seen, if this is due to blood pooling in the venous system, or local/systemic vasoconstriction, or just local skin plexus vasoconstriction/dilataion. Can skin temperatures be used as an indicator of systemic or just local vasomotor actvity? Also, do variables such as subcutaneous fat, or lack thereof, complicate these measurements. Before jumping to conclusions, and saying, that there is a solid correlation with skin temperatures and cardiovascualr activity, I want to see if any other people have had experience with skin temperature and LBNP/Centrifuge. Thank you for the tip James.

I am not aware of other non-invasive options available besides plethysmograph and NiR Imaging, although each method comes with limitations that have already been alluded to earlier. To measure blood temperature, flow rate and volume going to the skin, you probably need to insert a catheter with flow and temperature sensors into the vein emptying blood into the region of interest. Jim Cotter in U Otago may be doing this in PAD patients.

There is certainly an increase in blood flow, and therefore local heat storage, to the skin as temp increases, but whether this is a shunt or pooling of blood is a subject for further discussion, bearing in mind that blood flow rate needs to be maintained, especially in an exercising condition,

Hello everyone,

I just want to point out the experimental finding that human skin temp can be different in different body parts and in peripheral parts (e.g. hand and fingers) can vary with ambient temp. See JPhysiol 1987, 390; 383P.

Yes K.W. I am aware of this. Thanks for the tip. The fingers and toes are anastomosis, which are quite distal to the core. The distal extremities fingers and toes, have the advantage because, given that they are relatively free of large fat/mucle mass, the changes in vasomotor activity can be seen by decreases/increases in cutaneous skin temperature. Now, the disadvantage is that during otherststatic stress, or thermostress, particulalry cold, blood is shunted away from the distal extremites quite quickly. Now, if someone is measuring arm temperature more proximal to the core during orthostatic stress, and one also sees decreases in skin temp, can one say, "ahh, this could be an indicator of vasomotor activity in the skin, or in the major vessels or not". This is the predicament. In a recent centrifuge experiment, there were very strong correlations seen with skin temperatures of the medial arms/thighs, as well as hands/feet, with cardiovascular parameters. I should be done with the abstract shortly, which I can then post for feedback.

Chin-thank you for your comment regarding measuring cathetar insertion. Yes, that would seem logical to do, however our attempt is to show that skin temperature monitoring, being very practical and non-invasive, is a reliable inidcator of either, cutaneous vasomotor actvity, or that skin temperature reflects venous pooling or TPR.

Thanks for the comments and article suggestions.

As has been noted previously, there are a number of papers that use temperature monitoring over the wrist as a measure of circadian physiology. This is most specific to the wrist or ankle, locations that have little fat/muscle tissue, so provide a good reverse indicator of core temperature. Would it be feasible to have two monitors to get a sense of local tissue temperature (due to blood, activity, etc) vs. core?

Well Karyn, I hope to have some final results pretty soon of an experiment performed on a human centrifuge, where we employed a total of 6 skin temperature probes (5 peripheral and 1 central) to monitor body temperature during sustained acceleration. Once the analysis is complete for all of the data collected from the sensors, then we should have a better idea of correlations between blood flow/distribution and skin peripheral and core temperature.

Although we did not specifically measure venous pooling vs. skin temperatures, it has been a fairly consistent finding that skin temperature in the legs decreases with bed rest and space flight when blood distribution would be more centrally located (cephalad shift). It has been awhile since I worked in this area, but I remember that there is a measurable change in skin temperature with acute changes in posture.

Novak L, Ulicny B, Wilhelm Z, Barak J, Koshcheev VS,

Utekhin BA, Kuznets EI, and Yakovleva EV. The simulation

of thermal microclimate in the garment similar to those observed

in weightlessness. The Physiologist 31, Suppl: S38–S39, 1988.

Krupina TN and Ya Tizul A. Clinical aspects of changes in the

nervous system in the course of 49-day antiorthostatic hypokinesia.

Ksom Biol Aviakosm Med 11: 26–31, 1977.

Tizul Ya A. The Function of Thermoregulation in Protracted

Limitation of Motor Activity (Hypokinesia). Houston, TX: NASA,

1974, p. 1–7. (Spec. NASA Rep. F-15, 566)

Novak L, Genin AM, and Kozlowksi S. Skin temperature and

thermal comfort in weightlessness. The Physiologist 23, Suppl:

S139–S140, 1980.

Lee, SMC., WJ Williams, SM Schneider. Role of skin blood flow and sweating rate in

exercise thermoregulation after bed rest. J Appl Physiol 92:

2026–2034, 2002;

It is difficult to measure venous return in man during action.Insufficient venous return is the main cause of inverse recovery among cotton textile workers in weaving room because of hundred percent humidity in the section because of process demand. Due to higher skin temperature and low venous return develops inverse recovery which causes occupational disease of cardiovascular system Increase skin temperature is not serious as long as core temperature is differ significantly.. PCG,CLI

Hey Paresh. Thanks for the info. Do you happen to have an article about the textile workers skin temperature? That would be very interesting to know more about that.

Why not you use plethysmography (a standard method was earlier) to follow blood pooling in the arm? In these case you would have the data of volume change what you can correlate with your skin temp that you measure.

Thats not a bad idea to use plethysmography for future studies. And yes, that would help immensley to record volume change and temperature change together, which hopefully would then give some solid information concerning blood shifts and temperature fluctuations.

Eugene Maevsky 

Perfectly possible to measure and record temperature response using matrix thermal imaging cameras with high resolution