Skin conductance as a means to predict hypotension following spinal anaesthesia

Abstract

AUC B, as a parameter of SC, may predict severe arterial hypotension after SA in the elderly.

Haemodynamic effects of central neural blocks

“…Usually, these haemodynamic effects could be considered as normal reactions to central neural blockade (1). However, severe hypotension may have significant outcomes in elderly patients with limited reserve and atherosclerosis, coronary artery disease (3,15). The incidence of hypotension is reported to occur from 5% to 81% depending on the definition (2, 9).…”

An observational study of skin conductance monitoring as a means of predicting hypotension from spinal anaesthesia for caesarean delivery

“…In a previous study, a calculation of the area under the curve of skin conductance fluctuations, but not NFSC, proved helpful in predicting moderate or severe hypotension, showing reasonable sensitivity and specificity among older patients having spinal anaesthesia. 10 In contrast, the negative outcome in this study may reflect age-related differences in skin conductance, sympathetic activity, anxiety or other responses to spinal anaesthesia or the higher baseline sympathetic activity associated with pregnancy. The results of this study did support previous research 10 showing a reduction in sympathetic activity after spinal anaesthesia within a skin site above the sensory block, at least in the cholinergic sympathetic distribution of the palm.…”

“…10 We classified the degree of hypotension using ranges of systolic pressure reduction that correlate with the risk of maternal symptoms 12 and defined severe or very severe hypotension as a reduction likely to result in fetal bradycardia. 13 Although we considered that the categories used by Hanss et al 6 were based on less exacting evidence, these were also used for analysis to permit historical comparison with their findings.…”

“…Based on our previous study, 10 we anticipated that a method of calculating the area under all skin conductance fluctuations (defined by peak and trough) detected within the sampling time, which we called AUC B, 10 was the variable most likely to be of value for the prediction of hypotension.…”

“…Skin conductance is convenient to use in clinical settings and provides data within 15 s. 9 The area under the curve (AUC) of skin conductance fluctuations is of value in predicting risk of hypotension following spinal anaesthesia in elderly patients. 10 We designed an observational pilot study to investigate the value of skin-conductance monitoring as a method of predicting hypotension following spinal anaesthesia for elective caesarean delivery. We postulated that skin conductance before spinal anaesthesia might differ between women who subsequently experienced no or mild versus more severe hypotension and that measurement of these skin conductance values could be used to predict the risk of severe hypotension in this surgical population.…”