Infrared Thermography as a Method of Verification in Raynaud’s Phenomenon

Raynaud’s phenomenon (RP) is characterized by the episodic whitening of the fingers upon exposure to cold. A recently described thermographic algorithm was proposed as a diagnostic replacement of the currently applied finger systolic pressure (FSP) test. The aim of the study was to evaluate the performance of the thermographic algorithm when applied in patients suspected of having RP. Forty-three patients were examined using thermographic imaging after local cooling of the hands in water of 10 °C for 1 min. The thermographic algorithm was applied to predict the probability of RP. The performance of the algorithm was evaluated with different cut-off levels. A new algorithm was proposed based on patients from the target population. The performance of the tested algorithm was noninferior to the FSP test, when a cut-off level of 0.05 was applied, yielding a sensitivity and specificity of 69% and 58%, respectively. The accuracy was 66%. The FSP test had a sensitivity and specificity of 77% and 37%, respectively, and the accuracy was 59%. The thermographic method proved useful for detecting RP and was able to replace the FSP test as a diagnostic test. The alternative algorithm revealed that other thermographic variables were more predictive of the target population, but this should be verified in future patients.

Cardiovascular regulation during head-up tilt in healthy 20–30-year-old and 70–75-year-old men

This study compared the heart rate, finger arterial pressure (AP) and electromyographic (EMG) activity of selected anti-gravity muscles during the initial and prolonged phases of orthostatic stress in healthy young and older men. Beat-by-beat recordings of heart rate, finger systolic pressure, diastolic pressure and mean AP were made during supine rest and 5 min of 90 ° head-up tilt (HUT) in 18 young (23±1 years) and 15 older (73±1 years) men. The EMG activity of the soleus, tibialis anterior and vastus medialis muscles was recorded. During the first 30 s following 90 ° HUT (immediate response), the young men exhibited significant (P < 0.05) decreases in finger systolic pressure, diastolic pressure and mean AP, followed by a sustained increase in finger AP during the 5 min following 90 ° HUT (prolonged response). The immediate and prolonged finger AP and diastolic pressure responses were not significantly different (P > 0.05) from the values at supine rest for the older men. The mean root mean square EMG activity of the soleus, tibialis anterior and vastus medialis muscles during 90 ° HUT was not significantly different (P > 0.05) from that at supine rest for either group. These results demonstrate that, when compared with healthy older men, young men show larger reductions in finger AP during the initial phase of orthostatic stress. However, during the prolonged phase of orthostatic stress, older men maintain resting finger AP, whereas young men demonstrate a reflex overshoot in finger AP. Finally, differences in lower-limb anti-gravity muscle activation do not account for the contrasting finger AP responses of healthy young and older men.

Arterial Spasticity and Cold Intolerance in Relation to Time after Digital Replantation

Cold induced arterial vasospasm was studied in ten patients with single digit replantation, by measuring finger systolic pressure at different finger temperatures. Each patient was examined three times; within 2 weeks of surgery, after 1 year and after 3 years. The replantations were performed using long arterial and venous grafts. Cold-related vasospasm is established during the first year after trauma, and thereafter seems to be persistent. It is concluded that the subjective cold intolerance, which affects all patients after digital amputation regardless of whether replantation is performed or not, is partly due to vasospasm. It is less pronounced in patients without pathological vasospasm in the replanted digit. Cold intolerance is likely to decrease during the first 2 years after replantation, but not to disappear completely.

Cold Sensitivity After Replantation in Relation to Arterial Circulation and Vasoregulation

Cold intolerance is a common problem after injuries to the band. To elucidate the mechanism of this cold sensitivity, eight patients with successful replantations of amputations of the thumb or index finger were studied one and half years later. In six patients the Doppler signal from the anastomosed arteries was normal and in two patients signs of mild stenosis were found. All patients had normal or slightly reduced basal finger systolic pressure in the replanted finger. Six had signs of marked vasospasm. Alpha-receptor blockade had no effect on the cold-induced decrease in finger systolic pressure in the replanted finger. It is concluded that cold intolerance after hand injuries results from a defect in vasoregulation and is not caused by organic insufficiency of the circulation.