///2015 Abstract Details
2015 Abstract Details2019-08-02T16:54:43-06:00

Accuracy of a Non-invasive Device for Spot-check Hemoglobin Measurement after Cesarean Delivery

Abstract Number: F-16
Abstract Type: Original Research

Christine A. Piascik M.D.1 ; Adrienne Duffield M.D.2; Victoria Yin M.D.3; Bharathi Ramachandran B.S.4; Alexander Butwick MBBS, FRCA, MS5

Background: Postpartum anemia (PA) is an underappreciated hematologic morbidity, affecting up to 21% of women one week after delivery.(1) Non-invasive devices that measure venous hemoglobin (vHb) may be of value in screening for PA prior to hospital discharge. The Pronto-7 device (Masimo Corp, Irvine, CA)(2) is a non-invasive spot-check device that uses multi-wavelength spectrophotometry for hemoglobin (SpHb) measurement. There is limited data describing the accuracy/precision of this device among postpartum women.(3) We present an interim analysis describing the Pronto-7 device performance in hospitalized women after cesarean delivery (CD).

Methods: After IRB approval, we performed an interim analysis of 42 healthy term parturients undergoing elective CD with neuraxial anesthesia who were enrolled in an ongoing prospective study. vHb and SpHb measurements were performed at 24 hr and 72 hr after CD. SpHb spot-checks were performed with a Pronto-7 device. To assess the level of agreement between SpHb and vHb values, we calculated the bias (mean difference and 95% CI) and limits of agreement (LOA), corrected for repeated measurements using a linear mixed-effects model. By examining for interaction, we determined whether the bias was consistent over time. P <0.05 as statistically significant.

Results: Mean (SD) vHb and SpHb values at 24hr post-CD were 10.4 (1.2) g/dl and 12.7 (1.0) g/dl respectively, and at 72 hr post-CD were 10.6 (1.1) g/dl and 12.8 (0.9) g/dl respectively. A Bland-Altman plot of individual SpHb and vHb values is shown in Figure. We observed a significant positive bias for the SpHb values compared to vHb (2.25 g/dl; P<0.001); the 95% CIs were 1.99 g/dl and 2.50 g/dl. The LOA were wide: - 0.06 g/dl and 4.51 g/dl. (Figure). We observed no interaction between bias and time of measurement (P=0.57).

Conclusion: In this interim analysis of SpHb and vHb values of post-CD women, the Pronto-7 had a high positive bias with wide LOA. Although this device may have potential value as a screening device for PA, further modifications are needed to improve accuracy and precision prior to clinical use in the early postpartum period.

References: (1) Ann Hematol 2011;90:1247-53 (2) http://masimo.com/pronto-7/index.htm (3) Medical Devices 2014:7:11-16.

SOAP 2015