Abstract ID: A20

Abstract Title: Ultrasound-assisted interscalene catheterization for continuous interscalene block in outpatients having shoulder surgery

Authors: Fredrickson, FANZCA M¹, Dalgleish, FRACS A², Ball, FRACS C³
Southern Cross Hospital Group Auckland Auckland New Zealand
Poster Type: Either

ABSTRACT BODY

Introduction: Continuous interscalene block (CISB) following shoulder surgery has been shown to provide better analgesia and patient satisfaction than opioid analgesia (1). Ultrasound (US) guidance for peripheral nerve block is growing in popularity (2), but reports on the use of US to assist ISB are limited to case reports (3). We report on the routine use of US to assist interscalene catheter (ISC) placement for ambulatory CISB following shoulder surgery, and detail the effectiveness, complications and patient perception of this analgesic modality.
Materials and Methods: Following institutional review board approval and informed consent, patients scheduled for elective shoulder surgery in a community practice setting were included. Prior to surgery and under US guidance (Sonosite 180®), an insulated tuohy needle (BBraun Contiplex®) was placed in real time into the interscalene space at C6 with a nerve stimulator (NS) set to 1.0 mA (pulse width 0.1 ms). The needle was then manipulated until an appropriate motor response was obtained at a current < 0.5mA. A non-stimulating catheter was advanced 3cm past needle tip. Lidocaine 2% 0.3ml/kg was administered via the ISC followed by ropivacaine 0.5% 0.25ml/kg. Surgery was performed with all patients under N2O/desflurane general anesthesia. At the end of surgery, ropivacaine 0.2% 2ml/hr with an hourly on demand 5ml bolus was administered via an ambulatory elastomeric pump (PainBuster®, Surgical Synergies Ltd). Discharge home occurred on the day of surgery or first post-operative morning.
Results: 60 patients were studied (rotator cuff repair 43%, other shoulder surgery 57%). 55 (91%) patients had an initial verbal analogue pain score (VAS) in PACU of 2 or less. A further 4 achieved a VAS of 2 or less following 1 cm withdrawal of the ISC and subsequent administration of 20ml 0.5% ropivacaine. One patient required replacement of the ISC in PACU. The worst VAS's throughout the treatment were very low (Table 1). Complications within the first 24 postoperative hours included dense motor block requiring cessation of the infusion (3 patients), horner’s syndrome (5), dyspnea (5) and hoarseness (3). ISC's were removed by patients after a mean of 3.9 days. Complications at home included ISC failure (3, all on day 2), post-bolus dyspnea (2), post-bolus hoarseness (1) and ISC entry site leakage (2). Only 3 patients required post-operative opioids, 1 for persistent shivering in PACU, 1 for T2 dermatome pain (axillary incision) and 1 for ISC failure at home. The most commonly reported complaint was the weight/bulkiness of the device (10 patients). No patient developed ISC entry site infection. There were no new neurological symptoms beyond day 21.
Discussion: Our data suggest that ultrasound-assisted placement of an ISC is a feasible alternative to NS-guided techniques. In our setting, US-assisted ISC placement was associated with excellent postoperative analgesia and high patient satisfaction. There was a low incidence of significant complications and catheter failure.
References (1) Anesthesiology'97;87:1343 (2) RAPM'05;30:321 (3) RAPM'03;28:3

ATTACHED FILES

A20_Figure 1.doc

A20_Table 1.doc

A20_USImageCISB.doc

Reg Anesth Pain Med 2005; 30(3):A20