Detecting central-venous oxygen desaturation without a central-venous catheter: Utility of the difference between invasively and noninvasively measured blood pressure

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• 作者：Junji Kumasawa ; MD^a ; ^b ; ^{jkumakumakuma@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Akitoshi Ohara ; MD^b ; Hisakazu Kohata ; MD^b ; Kenichi Aoyagi ; MD^b ; Shingo Fukuma ; PhD^a ; Shunichi Fukuhara ; MD ; DMSc^a ; ^c
• 关键词：Blood pressure monitors ; Sensitivity and specificity ; ROC curve ; Central-venous catheterization ; Oximetry ; Shock
• 刊名：Journal of Critical Care
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：33
• 期：Complete
• 页码：257-261
• 全文大小：395 K

文摘

The objective was to determine whether central-venous oxygen saturation (ScvO₂ < 70%) can be detected from the difference between invasively and noninvasively measured systolic blood pressure (BP) (ie, ΔBP defined as arterial BP minus noninvasive BP).

Methods

This is a cross-sectional study at a single medical and surgical intensive care unit in Japan. All hypotensive patients admitted to intensive care unit were eligible. Arterial BP was measured via a radial-artery catheter, and noninvasive BP on the same side was measured via a brachial cuff. ScvO₂ was measured by gas analysis of blood sampled from a central-venous chatheter (CVC). We calculate the area under the curve for ΔBP as an indicator of ScvO₂ < 70%.

Results

Usable data were obtained from the records of 111 patients. The median and interquartile range of ΔBP and ScvO₂ were − 4 mm Hg (− 11, 6) and 67% (60.9, 73.9), respectively. The area under the curve of ΔBP as an indicator of ScvO₂ < 70% was 0.81 (95% confidence interval [CI], 0.73-0.89). With a cutoff ΔBP of 0, sensitivity was 65.7% (95% CI, 53.1-76.8), specificity was 97.7% (95% CI, 88.0-99.8), and positive predictive value was 97.8 (95% CI, 88.2-99.9).

Conclusions

ΔBP can indicate whether ScvO₂ is lower than 70%. When that difference is greater than 0, ScvO₂ is very likely to be lower than 70%.