Correlation between central venous oxygen saturation and mixed venous oxygen saturation in surgical patients: A
Ling Li1,2,3, Li-Xian He1,2,3, Yun-Tai Yao4,5,6
1Department of Anesthesiology, Fuwai Yunnan Hospital, Chinese Academy of Medical Sciences, Affiliated Cardiovascular Hospital of Kunming Medical University, Kunming 650102, China.
Background:
The validity of central venous oxygen saturation (ScvO2) as a surrogate for mixed venous oxygen saturation (SvO₂) in surgical patients remains uncertain.
Methods:
We systematically searched PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, VIP, and the Chinese BioMedical Literature & Retrieval System (SinoMed) up to March 31st 2026 for observational studies reporting paired perioperative ScvO2 and SvO2 measurements in surgical patients. Two reviewers independently screened studies, extracted data, and assessed quality using the Newcastle-Ottawa Scale (NOS). The primary outcome was clinical interchangeability, pre-defined as both the pooled mean difference (MD) 95% confidence interval (CI) and 95% limits of agreement (LOA) within ±5%. Correlation was a secondary outcome via Fisher's z transformation. For studies reporting multiple measurements within a single perioperative phase, arithmetic means were used to avoid unit-of-analysis errors. Random-effects models were prespecified for all pooled analyses, supplemented by pre-planned subgroup and sensitivity analyses to explore heterogeneity.
Results:
Twenty-eight studies including 1369 patients were analyzed. In studies reporting aggregated perioperative data (10 studies, n = 524), ScvO2 and SvO₂ were not clinically interchangeable: pooled MD was -0.49% (95% CI, -1.34 to 0.35; I² = 70.3%), and LOA (-12.15% to 11.17%) exceeded the predefined ±5% threshold for clinical acceptability, consistent with observations across perioperative phases. The pooled correlation was 0.72 (5 studies, n = 197; 95% CI 0.57-0.82; I² = 64.3%). Subgroup analyses showed narrower LOA and higher correlation in non-cardiovascular and off-pump procedures.
Conclusions:
ScvO2 is positively correlated with SvO₂ in the perioperative period. However, wide individual-level LOA indicate that the two measurements are not interchangeable in surgical patients. LOA are narrower in non-cardiovascular and off-pump procedures but remain outside clinically acceptable limits.
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