Which administration route of fentanyl better enhances the spread of spinal anaesthesia: intravenous, intrathecal or both?

Abstract

Both the spinal and systemic administration of fentanyl enhanced the spread of spinal anaesthesia. The co-administration of spinal and i.v. fentanyl produced a greater increase in the cephalad spread of spinal block.

Fractal Properties of Heart Rate Dynamics: A New Biomarker for Anesthesia—Biphasic Changes in General Anesthesia and Decrease in Spinal Anesthesia

“…Decreased DFAα1 has been observed in various disease conditions or under certain physical states, such as heart failure [ 23 ], before the onset of atrial fibrillation [ 29 ] and under cold face tests in healthy subjects [ 46 ]. However, when the local anesthetic was supplemented with fentanyl, we did not observe the synergetic effect of the sympathetic blockade as previously reported when fentanyl was intravenously administered [ 50 ]. We added 20 μg fentanyl (0.4 mL) to 1.2 mL of bupivacaine, increasing the injecting volume to 1.6 mL in patients in Group LMf.…”

Sympathovagal effects of spinal anaesthesia with intrathecal or intravenous fentanyl assessed by heart rate variability

“…Although the sympathovagal effects of spinal anaesthesia have been investigated, 4–8 there is no information about the sympathovagal effects of intrathecal or intravenous fentanyl added to spinal anaesthesia. Intravenous or intrathecal fentanyl supplementation may modulate the sympathovagal effects of spinal anaesthesia by augmenting the block of cardiac sympathetic block 9 or sedation associated with spinal anaesthesia 10,11 . Sinus bradycardia and hypotension are common complications associated with spinal anaesthesia.…”