Determining Epidural Catheter Location Using Nerve Stimulation With Radiological Confirmation

Purpose The epidural electrical stimulation test (EEST) is a highly specific and sensitive test for confirming placement of the epidural catheter in the epidural space. The purpose of this study was to investigate if the EEST could predict the spread and consumption of local anesthetic solutions during labour epidural analgesia. Methods This observational study was conducted in labouring parturients requesting epidural analgesia. The EEST was performed after the epidural catheter placement (T0) and repeated five minutes after a test dose with 2% lidocaine 3 mL (T1). The minimum current required to elicit the motor response at each time point was recorded.A loading dose of 0.125% bupivacaine 10 mL and fentanyl 50 lg was administered and followed by patient-controlled epidural analgesia with 0.0625% bupivacaine and fentanyl 2 lgÁmL -1 (baseline infusion 10 mLÁhr -1 , bolus dose 5 mL, lockout interval ten minutes, maximum dose 20 mLÁhr -1 ). The primary outcome was the correlation between the current required to elicit motor responses at T0 and T1 and the consumption of bupivacaine in the first two hours of epidural administration. The secondary outcomes included the muscle contraction patterns determined by the EEST and the incidence of failed, inadequate, or asymmetric blocks. Results The study was conducted in 102 parturients. The mean electric current required to elicit muscle response was 4.43 mA (range 1-10 mA) at T0, 5.97 mA (range 1-14 mA) at T1, and the mean D (T1-T0) current was 1.54 mA (range 0-8 mA). There was no correlation between either the mean baseline current required or the D (T1-T0) current and the total bupivacaine consumption at two hours. The incidence of inadequate blocks at two hours was 18%; however, none of the catheters required replacement. Unilateral left (34%) or right (31%) leg contraction was the most frequent pattern elicited by the EEST. Conclusions The EEST shows a wide range of electrical current requirements and elicits a variety of muscle twitch patterns on the lower limbs. Although it confirms the epidural placement of the catheter, the EEST cannot be used to predict the spread or consumption of the local anesthetic solution during labour epidural analgesia. RésuméObjectif Le test de stimulation e´lectrique pe´ridurale (TSEP) est un test extreˆmement spe´cifique et sensible qui

Section: Discussioncontrasting

confidence: 86%

The epidural electric stimulation test does not predict local anesthetic spread or consumption in labour epidural analgesia

Margarido

Dlacic

Balki

et al. 2013

“…[7][8][9][10][11][12] These studies also hypothesized that when using ES, a motor response evoked by a low current (< 1 mA) could serve as a warning sign of a needle or catheter approaching a nerve root or entering the subarachnoid space. [7][8][9][10][11][12] Passannante et al reported a case of total spinal block and permanent neurological damage resulting from an accidental subarachnoid and intraneural local anesthetic injection at a low current (0.2 mA) when a nerve stimulatorguided interscalene brachial plexus block was performed during general anesthesia. 13 In previous case reports, using ES, we demonstrated that a motor response occurs with: a) subarachnoid catheter placement at 0.4 mA; 8 b) subdural catheter placement at 0.3 mA; 9 and c) catheter tip placement in close proximity to nerve roots at 0.5 mA.…”

mentioning

confidence: 99%

The threshold current in the intrathecal space to elicit motor response is lower and does not overlap that in the epidural space: a porcine model

Tsui

Wagner

Finucane

2004

Self Cite

P Pu ur rp po os se e: : Using electrical epidural stimulation, a current of 1 to 10 mA is required to confirm the presence of the tip of an epidural catheter in the epidural space. The purpose of this study was to examine the hypothesis that the threshold current required to elicit a motor response in the intrathecal space is significantly lower than that in the epidural space in a porcine model.

“…The use of low current epidural stimulation to confirm and guide epidural catheters to specific spinal locations (Tsui test) has been recently described. [10][11][12] This technique confirms the location of the epidural catheter tip by eliciting motor responses corresponding to the specific myotome level of the stimulating catheter tip. This report describes the application of the Tsui test to assist with the accurate placement of an EBP via a thoracic epidural catheter in a patient with SIH after two previous unsuccessful blood patches.…”

Section: Regional Anesthesia and Painmentioning

confidence: 52%

Regional Anesthesia and Pain Targeted thoracic epidural blood patch placed under electrical stimulation guidance (Tsui test)

Morley‐Forster

Abotaiban

Ganapathy

et al. 2006

Purpose: This case report describes the use of electrical epidural stimulation (Tsui test) to confirm accurate placement of a thoracic epidural catheter when administering an epidural blood patch for headache management in a patient suffering from spontaneous intracranial hypotension. Clinical features:A 41-yr-old female presented to the Chronic Pain Clinic with a history of postural headache symptoms worsening in severity over several years. Two previous blood patches performed at T11-12 and T10-11 respectively provided short-term relief only. The presumed diagnosis of a spontaneous dural tear was confirmed by a nuclear flow test to be at T2-T4. The epidural site was accessed at T6 with a Tuohy needle. To accurately place the epidural blood patch at the level of the dural tear, the Arrow catheter with electrode adapter was advanced under nerve stimulation guidance to T4. Ten millilitres of autologous blood injected through the catheter was confirmed on magnetic resonance imaging, one hour postprocedure, to lie between T3 and T9. Sustained headache relief was achieved. Conclusion:The use of electrical stimulation guidance may be useful when precise epidural blood patch placement is required. Objectif