Comparison of the neutral and retracted shoulder positions for infraclavicular subclavian venous catheterization: a randomized, non-inferiority trial.

BACKGROUND There are controversies regarding the most efficient shoulder position during infraclavicular subclavian venous catheterization. We hypothesized that, regarding the success rate of subclavian venous catheterization, the neutral shoulder position would not be inferior to the retracted shoulder position. METHODS A total of 362 patients who underwent elective surgery were randomly assigned to two groups: those who underwent subclavian venous catheterizations in the neutral shoulder position (neutral group, n=181) or in the retracted shoulder position (retracted group, n=181). In the retracted group, a 1 litre saline bag was placed longitudinally beneath the spinal column between the scapulae to allow the shoulders to fall into a 'retracted' position. The incidence of failures to place the central venous catheters and complications such as arterial puncture, pneumothorax, or haemothorax were recorded. RESULTS The success rates were 95.6% (173/181) in the neutral group and 96.1% (174/181) in the retracted group. The difference of 0.5% was within the prespecified non-inferiority margin of 5% with a P-value of 0.017 [two-sided 95% confidence interval (CI), -0.036 to 0.047; upper limit of the 95% CI, 0.040]. There were four catheterization failures (2.2%) in the neutral group and two failures (1.1%) in the retracted group. Complication rates were not significantly different between the neutral and retracted groups [3/181 (1.7%) vs 4/181 (2.2%) for arterial punctures and 1/181 (0.6%) vs 1/181 (0.6%) for pneumothorax]. CONCLUSIONS The neutral shoulder position was as effective as the retracted shoulder position for infraclavicular subclavian venous catheterization. Shoulder retraction does not appear to be necessary for the infraclavicular subclavian venous catheterization. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT01368692.