A D Leonard1, C M Allsager, J L Parker, A Swami, J P Thompson. 1. Department of Cardiovascular Sciences, Clinical Division of Anaesthesia Critical Care and Pain Management, Victoria Building, Leicester Royal Infirmary, Leicester LE15WW, UK. antonleonard@doctors.org.uk
Abstract
BACKGROUND: External jugular venous pressure (EJVP) is a close estimate of central venous pressure (CVP) in patients undergoing mechanical ventilation in the supine position, but the effects of spontaneous respiration and posture on this relationship are not known. In this study, we compared CVP with EJVP measurements in 36 patients undergoing repair of proximal femoral fracture breathing spontaneously in the supine or lateral positions. METHODS: A standard general anaesthetic was administered with patients breathing spontaneously via a laryngeal mask airway and i.v. fluids administered according to an algorithm guided by CVP measurements. CVP and EJVP catheters were placed on the right side of the neck where possible. RESULTS: In the supine position, 185 paired measurements of CVP and EJVP and 79 in the lateral position were recorded by a blinded observer during surgery. In the supine position, the mean difference between CVP and EJVP was -0.3 mm Hg (limits of agreement -2.6 to +1.9 mm Hg, 95% confidence intervals for both upper and lower limits of agreement, respectively, were -2.9 to -2.2 and +1.6 to +2.2 mm Hg). In the lateral position, the mean difference was -1.2 mm Hg (limits of agreement -5.8 to +3.8 mm Hg, 95% confidence intervals -6.8 to -4.5 and +2.7 to +4.9 mm Hg). CONCLUSIONS: These data suggest that EJVP is an acceptable estimate of CVP in the supine position. Agreement was poor in the lateral position but was stronger for estimates of trend rather than absolute values. This could be explained by the direct effects of posture.
BACKGROUND: External jugular venous pressure (EJVP) is a close estimate of central venous pressure (CVP) in patients undergoing mechanical ventilation in the supine position, but the effects of spontaneous respiration and posture on this relationship are not known. In this study, we compared CVP with EJVP measurements in 36 patients undergoing repair of proximal femoral fracture breathing spontaneously in the supine or lateral positions. METHODS: A standard general anaesthetic was administered with patients breathing spontaneously via a laryngeal mask airway and i.v. fluids administered according to an algorithm guided by CVP measurements. CVP and EJVP catheters were placed on the right side of the neck where possible. RESULTS: In the supine position, 185 paired measurements of CVP and EJVP and 79 in the lateral position were recorded by a blinded observer during surgery. In the supine position, the mean difference between CVP and EJVP was -0.3 mm Hg (limits of agreement -2.6 to +1.9 mm Hg, 95% confidence intervals for both upper and lower limits of agreement, respectively, were -2.9 to -2.2 and +1.6 to +2.2 mm Hg). In the lateral position, the mean difference was -1.2 mm Hg (limits of agreement -5.8 to +3.8 mm Hg, 95% confidence intervals -6.8 to -4.5 and +2.7 to +4.9 mm Hg). CONCLUSIONS: These data suggest that EJVP is an acceptable estimate of CVP in the supine position. Agreement was poor in the lateral position but was stronger for estimates of trend rather than absolute values. This could be explained by the direct effects of posture.
Authors: Anja Hayen; Mari Herigstad; Michael Kelly; Thomas W Okell; Kevin Murphy; Richard G Wise; Kyle T S Pattinson Journal: Neuroimage Date: 2012-10-27 Impact factor: 6.556