Abstract
Objectives
During obstetric hemorrhage, peripheral vasoconstriction maintains heart rate and blood pressure until compensatory mechanisms are overwhelmed and patients deteriorate rapidly. Real-time perfusion measurements could quantify vasoconstriction, improving early recognition of hemorrhage and facilitating early intervention to reduce morbidity and mortality. The AccuFlow device makes rapid, non-invasive, quantitative measurements of perfusion, but has not been studied for hemorrhage detection or used in surgical settings. This study evaluated feasibility, tolerability, and preliminary efficacy of the AccuFlow for assessment of blood loss at cesarean delivery (CD).
Methods
In this pilot study, sensors were applied to the wrist, forearm, bicep, and chest wall of 25 patients undergoing scheduled CD. Postoperatively, sensors were removed and patients rated the AccuFlow and the standard anesthesia monitoring equipment on a validated comfort rating scale for wearable computers (CRS). Blood loss was estimated by the surgical team (EBL) and calculated from change in hematocrit, weight, and height (CBL). CRS scores were compared via Wilcoxon signed ranks tests. Coefficients of correlation between sensor readings and CBL, and between EBL and CBL, were compared using Fisher’s R-to-z transformation.
Results
There were no safety events; no participants requested device removal. CRS ratings of the AccuFlow and the standard monitoring equipment were similar (7.2 vs. 8.8, p=0.25). Change in wrist perfusion from delivery to dressing placement was more strongly correlated with CBL than was EBL (R=−0.48 vs. R=0.087, p=0.03).
Conclusions
The AccuFlow sensor is well-tolerated and shows promise in detecting intrapartum hemorrhage, though larger studies are needed.
Funding source: Division of Maternal Fetal Medicine, Women and Infants Hospital, departmental funds
Funding source: ThermaSENSE Corp
Acknowledgments
The authors wish to thank the Department of Anesthesiology at Women and Infants Hospital for their support of study.
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Research funding: The manufacturer of the AccuFlow device (ThermaSENSE Corp, Blacksburg, VA) provided the investigational device to the research team at no cost. Institutional funds from the Division of Maternal Fetal Medicine were used to purchase participant incentives (Amazon.com gift card for $10 US for each study participant).
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: Authors state no conflict of interest.
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Informed consent: Informed consent was obtained from all individuals included in this study.
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Ethical approval: Research involving human subjects complied with all relevant national regulations and institutional policies, is in accordance with the tenets of the Helsinki Declaration (as revised in 2013), and has been approved by the authors’ Institutional Review Board.
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