Effects of peripheral sympathectomy on thermoregulatory vascular control in the rabbit ear

Abstract

A rabbit ear model of the human digit was utilized to determine the vascular response to peripheral sympathectomy. Vascular responses were evaluated by subjecting chronically instrumented rabbits to a cold stress before and after sympathectomy surgery. The typical response to cold stress is for ear temperatures and auricular cutaneous perfusion to decrease during the cooling phase of the test and to increase toward baseline levels during the rewarming phase after cold exposure. Following peripheral sympathectomy, ear temperatures were significantly increased during both the cooling and rewarming phase of the cold stress test although overall ear perfusion and skin perfusion were not different from sham-operated rabbits. The responses observed in the rabbit ear following peripheral sympathectomy appear to mimic those noted in patients receiving digital peripheral sympathectomies for the treatment of refractory pain and ulceration. Peripheral sympathectomy may result in clinical improvements in patients because it improves both total digital and nutritional cutaneous blood flow. Peripheral sympathectomy in normal rabbit ears does not result in altered perfusion patterns with cold exposure although ear temperature is significantly higher. This pattern of changes suggests that the distribution of extremity perfusion is altered even though overall extremity perfusion and cutaneous perfusion per se are not significantly different from sham-operated controls. Complete sympathectomy was accompanied by a persistent increase in ear temperature and a dissociation between conductance and microvascular perfusion. Auricular conductance was transiently increased and then decreased to levels below preoperative control values. Microvascular perfusion is decreased immediately following amputation/replantation and thereafter increases.

Periarterial Sympathectomy Salvage of the Acutely Ischemic Hand

“…This has been documented in the laboratory setting to be an increase in diameter of 50 to 100 percent immediately, with subsequent additional increase at 30 min to 165 to 223 percent, and at 60 min to 187 to 204 percent. 22,23 In conclusion, the need to employ periarterial sympathectomy in the acute trauma setting will occur infrequently, but is a valuable tool to have in mind. Priority should be given to considering the possibility of intimal injury.…”

Appetibility and effect of neem (Azadirachta indica) leaf foods on weight performance and viability of pre-weaning rabbits (Oryctolagus cuniculus).

“…Indeed it is the biggest young rabbits who appropriate the central position in the nest box. This gives them better thermal comfort and thus allows them to better control the cold compared to the rabbits at the ends (Smith et al, 1998;De la Fuente et al, 2007;Romanovsky, 2014).…”