European Journal of Anaesthesiology



Original Article

Trendelenburg positioning after cardiac surgery: effects on intrathoracic blood volume index and cardiac performance


D. A. Reuter a1, T. W. Felbinger a1, C. Schmidt a1, K. Moerstedt a1, E. Kilger a1, P. Lamm a2 and A. E. Goetz a1c1
a1 Ludwig-Maximilians-University, Department of Anaesthesiology, Munich, Germany
a2 Ludwig-Maximilians-University, Department of Cardiac Surgery, Munich, Germany

Article author query
reuter da   [PubMed][Google Scholar] 
felbinger tw   [PubMed][Google Scholar] 
schmidt c   [PubMed][Google Scholar] 
moerstedt k   [PubMed][Google Scholar] 
kilger e   [PubMed][Google Scholar] 
lamm p   [PubMed][Google Scholar] 
goetz ae   [PubMed][Google Scholar] 

Summary

Background and objective: The efficacy of the Trendelenburg position, a common first step to treat suspected hypovolaemia, remains controversial. We evaluated its haemodynamic effects on cardiac preload and performance in patients after cardiac surgery.

Methods: Twelve patients undergoing mechanical ventilation of the lungs who demonstrated left ventricular ‘kissing papillary muscles’ by transoesophageal echocardiography, thus suggesting hypovolaemia, were positioned 30° head down for 15 min immediately after cardiac surgery. Cardiac output by thermodilution, central venous pressure, pulmonary artery occlusion pressure, left ventricular end-diastolic area by transoesophageal echocardiography and intrathoracic blood volume by thermo- and dye dilution were determined before, during and after this Trendelenburg manoeuvre.

Results: Trendelenburg's manoeuvre was associated with increases in central venous pressure (9 ± 2 to 12 ± 3 mmHg) and pulmonary artery occlusion pressure (8 ± 2 to 11 ± 3 mmHg). The intrathoracic blood volume index increased slightly (dye dilution from 836 ± 129 to 872 ± 112 mL m−2; thermodilution from 823 ± 129 to 850 ± 131 mL m−2) as did the left ventricular end-diastolic area index (7.5 ± 2.1 to 8.1 ± 1.7 cm2 m−2), whereas mean arterial pressure and the cardiac index did not change significantly. After supine repositioning, the cardiac index decreased significantly below baseline (3.0 ± 0.6 versus 3.5 ± 0.8 L min−1 m−2) as did mean arterial pressure (76 ± 12 versus 85 ± 11 mmHg), central venous pressure (8 ± 2 mmHg) and pulmonary artery occlusion pressure (6 ± 4 mmHg). The intrathoracic blood volume index and left ventricular end-diastolic area index did not differ significantly from baseline.

Conclusions: Trendelenburg's manoeuvre caused only a slight increase of preload volume, despite marked increases in cardiac-filling pressures, without significantly improving cardiac performance.

(Accepted February 2002)


Key Words: CARDIOVASCULAR PHYSIOLOGY, haemodynamics, blood volume; POSTURE, head-down tilt.

Correspondence:
c1 Correspondence to: Alwin Goetz, Department of Anaesthesiology, Ludwig-Maximilians-University, Großhadern University Hospital, Marchioninistr. 15, D-81377 Munich, Germany. E-mail: alwin.goetz@ana.med.uni-muenchen.de; Tel: +49 89 7097 1844; Fax: +49 89 7097 1848