Equal mixture of 2% lidocaine with adrenaline and 0.5% bupivacaine 20 mL provided faster onset of complete conduction blockade during ultrasound-guided supraclavicular brachial plexus block than 20 mL of 0.5% bupivacaine alone: a randomized double-blinded clinical trial.

INTRODUCTION: Recent evidence has questioned the advantage of local anesthetic (LA) combinations. This study tested the hypothesis that mixing rapid-onset (lidocaine) and long-duration (bupivacaine) LA would provide faster onset of complete conduction blockade (CCB) compared with bupivacaine alone and longer duration of analgesia compared with lidocaine alone during low-volume (20 mL) ultrasound-guided (USG) supraclavicular brachial plexus block (SCBPB). METHODS: Sixty-three patients receiving USG-SCBPB were randomly allocated into: group L: 20 mL 2% lidocaine with epinephrine 1:200 000; group B: 20 mL 0.5% bupivacaine; group LB: 20 mL of equi-volume mixture of both drugs. Sensory and motor blockade was recorded on a three point sensory and motor assessment scale at 10 min intervals for up to 40 min and the total composite score (TCS) at each time point was determined. The duration of analgesia was also noted. RESULTS: The mean time to CCB of group LB (16±7 min) was comparable (p>0.05) with group L (14±6 min) and group B (21±8 min) in patients who were attained CCB. However, the proportion of patients attaining complete conduction block (TCS=16/16) was significantly lower (p=0.0001) in group B (48%) when compared with group L (95%) and group LB (95%) at the end of 40 min. The median (IQR) duration of postoperative analgesia was longest in group B; 12.2 (12-14.5) hours, followed by group LB 8.3 (7-11) hours and 4 (2.7-4.5) hours in group L. CONCLUSION: At 20 mL LA volume, equal mixture of lidocaine and bupivacaine provided significantly faster onset of CCB compared with bupivacaine alone and longer duration of postoperative analgesia compared with lidocaine alone but shorter than bupivacaine alone during low-volume USG-SCBPB. TRIAL REGISTRATION NUMBER: CTRI/2020/11/029359.

Influence of arm position on the first pass success rates of ultrasound-guided infraclavicular axillary vein cannulation in spontaneously breathing patients: A randomised clinical trial.

BACKGROUND: Significant collapsibility during spontaneous respiration, deeper location, and smaller vein size are key challenging factors to safe infraclavicular axillary vein cannulation. Arm abduction reduces collapsibility, but interventional data supporting this observation is lacking. This study investigates the effect of neutral and abducted arm position on the first pass success rate of infraclavicular axillary vein cannulation in spontaneously breathing patients. METHODS: One hundred and twelve patients were randomly assigned to two arm positions, neutral or abducted by 90° at the shoulder joint. Under ultrasound guidance, the infraclavicular axillary vein was cannulated using an in-plane approach. The primary outcome was the first pass success rate of guidewire placement in the infraclavicular axillary vein. The secondary outcome measures were the number of attempts for successful cannulation, failure rate, and catheter tip malposition. RESULTS: Fifty-two patients in the neutral arm and fifty-six patients in the arm abduction group were compared according to the intention to treat analysis. The abducted arm position was associated with a higher first pass success rate (RR = 3.39, 95% CI = 1.47-7.85; p = 0.004) with fewer attempts (p = 0.005), lower failure rate (RR = 1.37, 95% CI = 1.16-1.61; p = 0.000) and lower catheter tip malposition (1.5 vs 15.8%; p = 0.012) when compared to the neutral arm position. CONCLUSION: Abducted arm position resulted in a significantly higher first pass success rate with a lower failure rate and catheter tip malposition during ultrasound-guided infraclavicular axillary vein cannulation in spontaneously breathing patients.

Sonographic visualization and cannulation of the axillary vein in two arm positions during mechanical ventilation: A randomized trial.

BACKGROUND: Abduction of the arm has been used for ultrasound-guided infraclavicular axillary vein cannulation. We evaluated the influence of arm position on sonographic visualization and cannulation of the axillary vein in patients receiving mechanical ventilation. METHODS: Sixty patients scheduled to undergo surgery under general anaesthesia with controlled mechanical ventilation were included in this prospective randomized study. The depth, size and distance of axillary vein to the pleura were recorded at three points: Point A, the most proximal part of the axillary vein visualized with adduction; Point A', Point A in abduction; and Point B, the most proximal part of axillary vein visualized in abduction. Cephalic movement of the clavicle at Point A' and the distance between Point A and Point B were noted. In Group A, cannulation was performed at Point A in the adducted arm and at Point B with the abducted arm in Group B after randomization. RESULTS: Abduction moved the clavicle cephalad by 2.2 ± 0.6 cm and increased sonographic visualization of the axillary vein by 2.2 ± 0.5 cm in length, when compared with adduction. The distance from the vein to pleura was higher in Point A' (p < 0.001). No differences were found during cannulation in terms of first-pass success rate or number of attempts. CONCLUSION: Abducted position moved the clavicle cephalad and allowed sonographic visualization of infraclavicular axillary vein approximately 2 cm more proximally than with the adducted arm, with a comparable rate of cannulation success.