Classical positioning decreases subclavian vein cross-sectional area in children

Background: Recommendations for subclavian vein catheter placement in children are extrapolated from adult experience. The purpose of this study was to determine the ideal body position to optimize the size of the subclavian vein in children for percutaneous catheter placement. Methods: Children underwent ultrasound imaging of the subclavian vein in four supine body positions: head in a neutral position with the chin midline (NL) and no shoulder roll (SR); head turned 90 degrees away (TA) and no SR; head NL with an SR; and head TA with an SR. The cross-sectional area (CSA) of the subclavian vein was calculated and statistical significance was determined using the Student's test and the Wilcoxon signed rank test. Results: Nine children participated in the study, with a mean age of 5.3 years. The CSA of the subclavian vein was 0.39 ± 0.24 cm² with the head NL and no SR, compared with 0.31 ± 0.20 cm² with the head TA or 0.32 ± 0.23 cm² with the head TA and SR. This represented a significant reduction in the CSA of the subclavian vein by 22% and 18%, respectively (p <0.05). Conclusion: In children, the recommended maneuvers of turning the head or turning the head and placing a posterior shoulder roll significantly reduce the cross-sectional area of the subclavian vein. Maintaining the head in a normal position with the chin midline without a shoulder roll optimizes subclavian vein size. Positioning children in this manner may serve to reduce the morbidity associated with percutaneous subclavian vein cannulation.