Après circulation extra-corporelle, la mesure continue de la Svo2 et la co-oxymétrie du sang mêlé ne sont pas interchangeables

Autor: Karim Bendjelid, Peter M. Suter, Jacques A. Romand, Nicolas Schütz
Rok vydání: 2004
Předmět:
Zdroj: Canadian Journal of Anesthesia/Journal canadien d'anesthésie. 51:610-615
ISSN: 1496-8975
0832-610X
DOI: 10.1007/bf03018404
Popis: Determiner la precision de la mesure continue (in vivo) de la saturation veineuse en oxygene du sang mele (Svo2) par catheter a fibres optiques chez les patients en post-circulation extracorporelle (CEC). Nous avons etudie prospectivement 14 patients (âge, 64 ± 8) post-CEC equipes d’un catheter arteriel pulmonaire. Le taux d’hematocrite moyen etait de 30 ± 4 %. Le catheter a ete calibrein vitro etin vivo suivant les recommandations du constructeur. Cinquante-six mesures simultanees de Svo2 continue (CSvo2) et de Svo2 mesuree (MSvo2) par hemoxymetre ont ete effectuees et les valeurs pairees ont ete analysees par regression lineaire. Pour que les deux mesures soient interchangeables, nous avons determine,a priori, une limite maximale de 3% (environ 5% de la mesure) comme difference acceptable entre les deux types de mesures. Toutes les mesures ont ete faites dans les quatre heures suivant la mise en place du catheter. CSvo2 est faiblement correlee a MSvo2 avec un coefficient de correlation r2 = 0,49 (P < 0,001). L’analyse de Bland-Altman objective un biais moyen de 0,8 ± 3% avec 36% des valeurs mesurees en dehors de la zone cliniquement acceptable. Pour des valeurs CSvo2 ± 65%, les mesures ne sont pas correlees (P = NS), le biais est de -2 ± 7% et 56% des valeurs mesurees en dehors de la zone cliniquement acceptable. Nos resultats objectivent que, dans les suites immediates d’une CEC, la mesure continue de la Svo2 et la co-oxymetrie du sang mele ne sont pas interchangeables. D’autres etudes sont necessaires afin de confirmer ces resultats et comprendre les phenomenes physiopathologiques a l’origine de l’absence de concordance entre les deux methodes. To determine the accuracy of continuous (in vivo) measurement of mixed venous oxygen saturation (SvO2), using a fibreoptic catheter, in patients having had cardiopulmonary bypass (CPB). Using a pulmonary arterial catheter, we prospectively studied 14 patients (age 64 ± 8) having had cardiopulmonary bypass. Mean hematocrit was 30 ± 4%. The catheter was calibrated in vitro and in vivo, according to the manufacturer’s instructions. Fifty-six simultaneous measurements of continuous SvO2 (CSvO2) and measured SvO2 (MSvO2) were taken with a co-oxymeter and the paired values were analyzed by the linear regression method. To make the two sets of measurements interchangeable, we established, a priori, a maximum limit of 3% (approximately 5% of the measurement), as being an acceptable difference between the two types of measurements. All the measurements were obtained within four hours of the placement of the catheter. CSvO2 was weakly correlated with MSvO2, with a correlation coefficient of r2 = 0.49 (P < 0.001). The Bland-Altman analysis demonstrates an objective mean bias of 0.8 ± 3%, with 36% of the values measured falling outside clinically acceptable limits. For values of CSvO2 ± 65%, the measurements were not correlated (P = NS). The bias was −2 ± 7%, and 56% of the values measured fell outside clinically acceptable limits. Our results demonstrate that, in the immediate aftermath of cardiopulmonary bypass, the continuous measurement of SvO2 and the co-oxymetry determination of mixed blood is not interchangeable. Other studies will be necessary to confirm these results and enable us to understand the pathophysiological phenomena accounting for the lack of agreement between the two methods.
Databáze: OpenAIRE
Externí odkaz: