Retention of finger blood flow against postural change as an indicator of successful sympathetic block in the upper limb

Abstract

BackgroundSympathetic block in the upper limb has diagnostic, therapeutic and prognostic utility for disorders in the upper extremity that are associated with sympathetic disturbances. Increased skin temperature and decreased sweating are used to identify the adequacy of sympathetic block in the upper limb after stellate ganglion block (SGB). Baroreflexes elicited by postural change induce a reduction in peripheral blood flow by causing sympathetic vasoconstriction. We hypothesized that sympathetic block in the upper limb reduces the decrease in finger blood flow caused by baroreflexes stimulated by postural change from the supine to long sitting position. This study evaluated if sympathetic block of the upper limb affects the change in finger blood flow resulting from postural change. If change in finger blood flow would be kept against postural changes, it has a potential to be a new indicator of sympathetic blockade in the upper limb.MethodsSubjects were adult patients who had a check-up at the Department of Pain Management in our university hospital over 2 years and 9 months from May 2012. We executed a total of 91 SGBs in nine patients (N=9), which included those requiring treatment for pain associated with herpes zoster in seven of the patients, tinnitus in one patient and upper limb pain in one patient. We checked for the following four signs after performing SGB: Horner’s sign, brachial nerve blockade, finger blood flow measured by a laser blood flow meter and skin temperature of the thumb measured by thermography, before and after SGB in the supine position and immediately after adopting the long sitting position.ResultsWe executed a total of 91 SGBs in nine patients. Two SGBs were excluded from the analysis due to the absence of Horner’s sign. We divided 89 procedures into two groups according to elevation in skin temperature of the thumb: by over 1°C (sympathetic block group, n=62) and by <1°C (nonsympathetic block group, n=27). Finger blood flow decreased significantly just after a change in posture from the supine to long sitting position after SGB in both groups. In the sympathetic block group, the ratio of finger blood flow in the long sitting position/supine position with a change in posture significantly increased after SGB compared with before SGB (before SGB: range 0.09–0.94, median 0.53; after SGB: range 0.33–1.2, median 0.89, p<0.0001).ConclusionOur study shows that with sympathetic block in the upper limb, the ratio of finger blood flow significantly increases despite baroreflexes stimulated by postural change from the supine to long sitting position. Retention of finger blood flow against postural changes may be an indicator of sympathetic block in the upper limb after SGB or brachial plexus block.

Management of vasopressor induced ischemia

“…29,30 Sympathetic blocks with local anesthetic may improve tissue perfusion as well. [31][32][33] Vascular studies such as duplex or CTA may be valuable at this time as well. If it is possible to decrease the dose of vasopressors without putting the patient at risk, then vasopressors ought to be titrated down.…”

Evaluation of the success of supraclavicular blockade performed under general anesthesia in arthroscopic surgery of the shoulder by using Perfusion Index

“…PI is a non-invasive monitoring method that gives information about perfusion by using pulse oximetry waves [18]. It has been reported that non-invasive measurement of perfusion index is effective to determine the success of brachial plexus blocks [19,20].…”

Comparison of the effects of interscalene, supraclavicular and infraclavicular peripheral nerve blockades on perfusion index

“…A successful peripheral nerve blockade leads to sympathetic, sensory and motor blocks, respectively. While the evaluation of a sensory and motor block depends on the patient's cooperation, a deep sympathetic block after a brachial plexus blockade may be evaluated from physiological changes that may occur, such as vasodilation, blood flow and skin temperature [4][5][6]. However, these methods are subjective, time-consuming and may be difficult due to sedation, and may vary depending on environmental conditions.…”