Microvascular skin response to local cooling and body tilt early after digital replantation

To elucidate the alteration in cutaneous microvascular reactivity early after replantation (14-21 days), laser Doppler (LD) flow changes evoked by direct and indirect local cooling and head-up body tilt were studied in the replanted digits (n = 10) and compared with those evoked in the healthy contralateral digits of the same patients (n = 10). During the first 3 minutes of direct cooling of the injured hand, LD flow increased significantly compared with the LD flow before cooling, which confirms that moderate vasodilation is the dominant component of the response to local cooling in skin microcirculation in the early period after replantation. During body tilt, LD flow in the healthy contralateral digit decreased significantly in only the first minute, while LD flow in the replanted digit started to decrease in the second minute after tilting; the decrease was significant from the third to the sixth minute. These results are consistent with the hypothesis that increased human skin alpha-adrenergic receptor sensitivity may be present as early as 2 to 3 weeks after replantation.