Correlation of mixed venous and central venous oxygen saturation and its relation to cardiac index

Abstract

Background and Aim: The clinical applicability of substitution of central venous oxygen saturation for mixed venous oxygen saturations in monitoring global tissue hypoxia is still a matter of controversy. Hence aim of the study is comparison of paired samples of mixed venous and central venous oxygen saturation and comparison in relation to cardiac index in varying hemodynamic conditions. Materials and Methods: Prospective clinical observation: Postoperative cardiac surgical ITU: 60 adult patients, >18 years of age of either sex: A PAC was inserted through ® IJV, triple lumen catheter was inserted through ® IJV. Blood samples were taken from distal tip of PAC and central venous catheters. An arterial blood sample was drawn from either radial or femoral arterial line. Measurements: Continuous cardiac output monitoring. Analysis of blood samples for hemoglobin concentration and oxygen saturation. Mixed venous oxygen saturations and central venous oxygen saturations were compared. The study was carried over a period of 30h in the postoperative period and samples were taken at 6h intervals. Patients were classified into three groups as follows depending on the CI: Low (< 2.5 L/m 2), medium (2.5-4 L/m 2), high (> 4 L/ m 2) and correlated with Svo 2 and Scvo 2. Results: 298 Comparative sets of samples were obtained. Svo consistently lower than Scvo 2 throughout the study period. The difference was statistically significant. By using Bland-Altman plot, the mean difference between Svo 2 and Scvo 2 (Svo 2-Scvo 2) was-2.9% ± 5.14 and confidence limits are + 7.17% and-12.97%. The coefficient r is > 0.7 throughout the study period for all paired samples. The correlation Svo 2 and Scvo 2 with cardiac index in all the three groups were >0.7. Conclusion: Scvo 2 and Svo 2 are closely related and are interchangeable. Even though individual values differ trends in Scvo 2 may be substituted for trend in Svo 2

Evaluation of the Efficacy of Epinephrine as a Vasopressor in the Management of Severe Sepsis: A Randomized Controlled Study

“…[22,23] However, there are literatures where SvO2 has been compared to ScvO2 and a value of 65% has been correlated with 70% for patients with sepsis. [24] An important target parameter in the surviving sepsis campaign guidelines for assessment of adequacy of resuscitation is ScvO2. A value of ≥ 70% has been advocated.…”

Central venous oxygen saturation does not correlate with the venous oxygen saturation at the surgical site during abdominal surgery

“…The average span quoted in literature varies between −1 and +7 percentage points, but sometimes even extreme differences between the two oxygen saturations are reported [2,7,14,15,17,20,24].…”

“…Intraoperative changes of the cardiac index might influence local tissue oxygenation. But with the exception of manifest heart failure occurring in septic shock no influence of the cardiac index on the correlation between SvO 2 and ScvO 2 has been described [1,14,20]. In general, SvO 2 or ScvO 2 might serve as surrogate for the balance between systemic oxygen delivery and consumption.…”

“…Previous studies over the last almost 40 years found contradictory results regarding the question whether ScvO 2 and SvO 2 are equivalent or interchangeable. A number of studies described a good correlation between both oxygen saturations [1,7,[14][15][16]19,21,26]. On the other hand, many authors found opposite results [2,5,6,9,12].…”

Peripheral Circulatory Features during High-Frequency Jet Ventilation

“…Газовый состав смешанной венозной крови определялся микрометодом Аструпа из подключичной или яремной вены [8,9]. Корректность такого подхода была доказана специаль ными исследованиями у 18 и больных (сепсис -6, постгемор рагическая гиповолемия -4, коматозное состояние -8), в ко торых различия в величинах PvO 2 центральной вены и легочной артерии не превышали 1,5 мм рт.…”