The effect of cooling on toe systolic pressures in subjects with and without Raynaud's syndrome in the lower extremities

The Influence of Heating on Toe pressure in Patients with Peripheral Arterial Disease

BACKGROUND AND AIM

The toe skin temperature in vascular patients can be low, making reliable toe pressure measurements difficult to obtain. The aim of this study was to evaluate the effect of heating on the toe pressure measurements.

MATERIALS AND METHODS

A total of 86 legs were examined. Brachial pressure and toe pressure were measured at rest in a supine position using a laser Doppler device that also measured skin temperature. After heating the toes for 5 min with a heating pad, we re-measured the toe pressure. Furthermore, after heating the skin to 40° with the probe, toe pressures were measured a third time.

RESULTS

The mean toe skin temperature at the baseline measurement was 24.0 °C (standard deviation: 2.8). After heating the toes for 5 min with a warm heating pad, the skin temperature rose to a mean 27.8 °C (standard deviation: 2.8; p = 0.000). The mean toe pressure rose from 58.5 (standard deviation: 32) to 62 (standard deviation: 32) mmHg (p = 0.029). Furthermore, after the skin was heated up to 40 °C with the probe, the mean toe pressure in the third measurement was 71 (standard deviation: 34) mmHg (p = 0.000). The response to the heating varied greatly between the patients after the first heating-from -34 mmHg (toe pressure decreased from 74 to 40 mmHg) to +91 mmHg. When the toes were heated to 40 °C, the change in to toe pressure from the baseline varied between -28 and +103 mmHg.

CONCLUSION

Our data indicate that there is a different response to the heating in different clinical situations and in patients with a different comorbidity.

Cold-Induced Skin Disorders

Background:

Humans are commonly exposed to extremes in temperature. Fortunately, our skin behaves as an anatomic and physiologic barrier during these periods. Exposure to cold temperatures may result in a variety of symptoms and disorders.

Objective:

Our current understanding of the pathophysiology, clinical presentation, and therapies of cold-induced skin disorders are reviewed.

Methods:

Studies, reviews, and book chapters that contained information on cold-induced skin disorders were reviewed.

Conclusion:

Cold-induced skin disorders are a heterogeneous group of disorders that cause great morbidity, particularly in cold climates. These entities can be classified as physiologic or pathologic responses to freezing or nonfreezing cold exposure.

The challenge and importance of defining critical limb ischemia

Patients with critical limb ischemia are at risk of limb loss and have very high cardiovascular and total mortality rates, which are greater than can be accounted for by the usual risk factors for atherosclerosis. A definition of critical ischemia is necessary to determine the natural history of the disease and to assess and compare the efficacy of various forms of therapy. The definition needs to be based on hemodynamic criteria because clinical manifestations and outcomes are not reliable. The reasons for the difficulties in arriving at a generally acceptable definition are explored. Building on the previous work of others, modified hemodynamic definitions for critical and subcritical ischemia, which include measurements of pressures and of indices of microcirculation, are proposed.

Effect of temperature on digital systolic pressures in lower limb in arterial disease

BACKGROUND

Toe pressures correlate with the chances of healing of skin lesions and with the risk of amputation and mortality. They are not affected by incompressibility of the tibial vessels, which may render ankle pressures inaccurate and reflect the overall arterial obstruction down to the digits. Digital pressures, however, may be affected by temperature.

METHODS AND RESULTS

Measurements under routine laboratory conditions were compared with those at controlled temperatures in 77 limbs with arteriosclerosis obliterans. The desired local temperatures were attained by perfusing water through the cuffs for 7 minutes before the measurements while the flow was interrupted by a tourniquet to allow equilibration of the toe and water temperatures. Mean toe pressure of 34 +/- 4 mm Hg at 10 degrees C was significantly lower (p less than 0.001) than the values during routine measurements (57 +/- 4 mm Hg) and at 30 degrees C (69 +/- 4 mm Hg). The pressure at 30 degrees C was 10 +/- 3 mm Hg higher than during routine measurements when initial digit temperature was below 30 degrees C (p less than 0.01) but not when it was higher. Measurements at 3 degrees C increments from 27 degrees C to 39 degrees C showed progressive increase in pressure (p less than 0.01).

CONCLUSIONS

Pressures at 36 degrees C and 39 degrees C were the highest but were not significantly different from each other. When toe temperature is low under routine conditions, the measured pressure may be falsely low, probably because of an effect on the main digital arteries that leads to delayed opening during deflation of the cuffs. Measurements at warm local temperature will increase the accuracy of the assessment of the severity of the arterial obstruction and may improve prediction of spontaneous healing of skin lesions.