Ultrasound guidance for difficult lateral popliteal catheter insertion in a patient with peripheral vascular disease

Abstract

Ultrasound guidance can facilitate lateral popliteal catheter insertion in patients in whom electrolocation has failed.

Increased electrical nerve stimulation threshold of the sciatic nerve in patients with diabetic foot gangrene

“…26 Only a few case reports have been published that describe difficulties in identifying the sciatic nerve in diabetic patients by electrical nerve stimulation. [10][11][12] Sites et al 9 reported on two patients with ultrasound-guided popliteal fossa blocks who required a minimum current of 2.4 and 2.6 mA, respectively, to elicit a motor response of the sciatic nerve. Other authors, however, performed sciatic nerve blocks in diabetic patients and were obviously successful in localising the nerve by electrical stimulation, although the stimulation threshold was not reported.…”

“…Only a few case reports have been published indicating an alteration of the motor response of the sciatic nerve to electrical stimulation in patients at risk of peripheral neuropathy. [9][10][11][12] A systematic evaluation as to whether the electrical stimulation threshold for a motor response of the sciatic nerve is substantially increased in diabetic patients has not been carried out before. Eur J Anaesthesiol 2013; 30:435-440 Diabetic foot disease is a potentially disabling and lifethreatening complication that affects up to 25% of patients with diabetes mellitus.…”

The Role of Continuous Peripheral Nerve Blocks

“…In certain situations ultrasound might be, at least theoretically, superior to nerve stimulation for example when sensory nerves are the target [143], after limb amputations [144] if there is no phantom sensation to guide nerve stimulation [145], when vascular puncture is an absolute contraindication like in anticoagulated patients [146], or when an electrically induced muscle response is impossible [147] or not desired [148]. However, ultrasound needle and catheter tip visualization are often difficult specially in deep structures.…”

Ultrasound as the only nerve localization technique for peripheral nerve block

“…Direct visualization of nerves with local anesthetic spread increases block success rate and may prevent complications [1]. With ultrasound, it is possible to perform peripheral nerve blocks in patients in whom other nerve localization techniques (nerve stimulation and paresthesia) are not useful [2,3].…”