Mixed venous blood gas sampling is not influenced by the speed of withdrawal in cardiac surgery patients

Intensive Care Med (2004) 30:19691973

DOI 10.1007/s00134-004-2392-4 BRIEF REPORTEmmanuel Sirdar

Jean-Gilles Guimond

Isabelle Coiteux

Sylvain BlisleDenis Babin

Marie-Claude Guertin

Andr DenaultMixed venous blood gas sampling

is not influenced by the speed of withdrawal

in cardiac surgery patientsReceived: 15 January 2003Accepted: 28 June 2004Published online: 28 July 2004

Springer-Verlag 2004This study was supported by the Plan de

pratique des anesthsiologistes de lInstitut

de Cardiologie de Montral.Electronic Supplementary MaterialSupplementary material is available in the

online version of this article at http://

dx.doi.org/10.1007/s00134.004.2392-4E. Sirdar J.-G. Guimond I. CoiteuxDepartment of Medicine,CHUM (Notre-Dame Hospital),1560 Sherbrooke East, Montreal, Quebec,

H2L 4M1, CanadaS. Blisle D. Babin A. Denault ())Department of Anesthesiology,Montreal Heart Institute,5000 Blanger Street East, Montreal,

Quebec, H1T 1C8, Canadae-mail: [email protected].: [phone] ext. 3732

Fax: [phone]M.-C. GuertinBiostatistics Department,Montreal Heart Institute,

5000 Blanger Street East, Montreal,

Quebec, H1T 1C8, CanadaAbstract Objective: To determine

whether mixed venous blood gas

sampling obtained by pulmonary

artery catheter (PAC) is influenced

by the speed of withdrawal.

Design: Prospective, observational

study. Setting: Surgical intensive

care unit at a university hospital.

Subjects: Twenty-five patients in the

early postoperative period of cardiac

surgery. Measurements and main

results: After verification of the adequate position of the PAC, measurements of mixed venous blood gas

oxygen saturation, oxygen partial

pressure (PO2), carbon dioxide partial

pressure (PCO2), pH and bicarbonates were obtained at two different

rates of withdrawal. A slow sampling

was taken at a mean speed of 3 ml/

min and a fast sampling at 18 ml/min

for each patient. The mean difference in venous oxygen saturation

between slow and fast samplings

was -0.181.3%, venous PO2:

0.21.3 mmHg, venous PCO2:0.10.9 mmHg, venous pH: 00.03,

venous bicarbonates: 0.030.5 mmol/l.

Conclusion: Using the Bland &

Altman method, we showed a satisfactory agreement between slow and

fast mixed venous blood gas sampling techniques when measuring

PO2, oxygen saturation, PCO2,pH

and bicarbonates though a PAC.Keywords Venous blood gases

Pulmonary artery catheterIntroductionPulmonary artery catheters (PACs) are widely used as a

guide for the evaluation of both the hemodynamic status

and systemic perfusion of patients in operating rooms and

intensive care units (ICUs) and, despite limitations on

their use [1, 2], one of the unique advantages of the PAC

is to allow the measurement of mixed venous blood gases.There are, however, controversies [3, 4] regarding the

influence of...