The possible existence of arteriovenous anastomoses (AVAs) in skin regions of the head and thorax has been investigated using the synchronous vasomotion of the AVAs. Simultaneous pairs of blood velocity recordings were made using pulsed, bidirectional Doppler ultrasound. In each pair of registrations, blood velocity was recorded in a reference artery supplying a skin area known to contain AVAs (the radial artery) together with one of four other arteries investigated, i.e. the facial artery, the angular artery, the temporal artery, and the cutaneous branches of the lateral thoracic artery. The typical large, regular fluctuations in blood velocities caused by synchronous vasomotion in the AVAs in the skin of the hand and fingers were observed invariably in the radial artery. Similar flow variations were found in the angular artery. The fluctuations in this and the radial artery were, in turn, found to be synchronous. However, we have not been able to find the flow pattern characteristic of AVA vasomotion in the temporal artery or in the cutaneous branches of the lateral thoracic artery. These results show that the skin area of the nose supplied by the angular artery contains AVAs. These AVAs partly may explain the important role of face skin in temperature regulation. These results also support the earlier assumptions that there are no or very few AVAs in the skin areas supplied by the temporal artery and the cutaneous branches of the lateral thoracic artery.

We have investigated the effect of severe local cooling on the vasomotor activity of the arteriovenous anastomoses (AVAs) and other finger vessels. The right third finger was subjected to local cooling (3°C) for 30–45 min in 21 healthy, thermoneutral subjects. Blood velocity in the third finger arteries of both hands was simultaneously recorded using ultrasound Doppler, and skin temperature and laser-Doppler flux from the pulp of the cooled finger were also recorded. The results demonstrate that the initial cold-induced vasoconstriction during severe local cooling involves constriction of the AVAs as well as the two main arteries supplying this finger. During cold-induced vasodilatation (CIVD), the maximum velocity values were not significantly different from those before cooling. Furthermore, the velocity fluctuations in the cooled finger were in most subjects found to be synchronous with the velocity fluctuations in the control finger. This indicates that the large blood flow to the finger and the high skin temperature during CIVD are caused by relaxation of the smooth muscle cells of the AVAs.

Maternal core temperature is highest in the first trimester but falls during pregnancy to a nadir 3 months post-partum. The ambient temperature required to reach the thermoneutral zone was 4 °C lower at 36 weeks of gestation compared with early pregnancy and late post-partum. Human temperature regulation is altered in pregnancy and for at least 3 months post-partum.

We have examined the influence of local cooling from 35 to 19 degrees C on spontaneous arterial blood velocity fluctuations in the acral skin of thermoneutral subjects. The skin temperature of one hand was gradually lowered in a water bath in two separate experimental runs. Simultaneous continuous blood velocity was measured from the third finger artery of both hands using ultrasound-Doppler. The large blood velocity fluctuations assumed to be caused by synchronous vasomotion of the arteriovenous anastomoses were invariably seen in the control finger artery throughout the two cooling periods, indicating that the subjects were in their thermoneutral zone. The velocity fluctuations on the cooled side remained nearly unchanged and closely correlated with those in the control finger artery during local cooling from 35 to approximately 21.5 degrees C. Below this temperature (range 23-20 degrees C) the velocity fluctuations ceased abruptly, and the velocity was nonfluctuating and continuously low. These results indicate a local thermal level below which there is abrupt, sustained closure of the arteriovenous anastomoses.

A wound support network between the primary home care service and the hospital is cost-effective, improves clinical efficacy of the home care services' work, and reduces the need for consultations at the hospital.