Skin microcirculation in patients with sequelae from local cold injuries

The microcirculation in the skin was assessed in 31 patients with sequelae from local cold injuries (LCI) in the extremities. All patients reported cold intolerance 3-4 years after the primary cold injury, which they sustained during military service. The used methods were laser Doppler fluxmetry, transcutaneous oxygen tension (TCpO2) and vital capillaroscopy. Neurovascular reflexes were stimulated by deep inspiration, digital cuff occlusion of venous and arterial circulation, neck cooling with an ice bag and water immersion at 5 and 15 degrees C. Unaffected lower or upper extremities were also investigated as part of a search for generalized effects of LCI. During immersion in ice water the cold-induced vasodilation (CIVD or Lewis' 'hunting' reaction) was profoundly delayed or abolished in the affected limbs. These also showed the lowest skin temperatures after 15-20 min of immersion. Additionally, a delayed CIVD was found in the unaffected feet of patients with a previous hand injury. TCpO2 resting values were decreased in the patients, but oxygen reappearance time, oxygen recovery index, postocclusive reactive hyperemia and the venoarterial reflex were normal. No capillary abnormalities were found. In conclusion, LCI induces disturbances in the CIVD, impairs cold tolerance and increases the risk of future cold injuries. These data demonstrate disturbances of reflex mechanisms mediated by the central nervous system. Neurophysiologic factors seem to be more important than ischemic mechanisms in the pathophysiology of late sequelae from LCI.