Pronto-7: Accuracy of Non-invasive Hemoglobin Measurement in Parturients

Serum hemoglobin (Hb) concentration is one of the most common laboratory tests measured when a pregnant woman (parturient) is admitted for a vaginal or cesarean delivery. The Hb concentration is normally measured from a venous blood sample in clinical laboratories using co-oximetry.

A new point-of-care pulse co-oximeter, the Pronto-7 (Masimo Corporation, Irvine, CA, USA), is a portable device that offers a non-invasive and quick spot-checking of Hb (SpHb). Measurement with the Pronto-7 takes about 60 seconds and does not require the transfer of blood samples to a laboratory. In addition to SpHb, the device provides a perfusion index (PI) value (a numeric estimation of the pulse strength at the measurement site), heart rate, oxygen saturation, and finger temperature. Potential advantages of the Pronto-7 include reduced staff work, decreased exposure to potential biohazards, and reduced pain and discomfort to the patient.

A similar technology is used in Radical-7 pulse co-oximeter (Masimo Corporation, Irvine, CA, USA) for non-invasive Hb measurement. Radical-7 has been evaluated in human volunteers undergoing hemodilution, in patients undergoing spine surgeries, major urological procedures, and in critically ill patients. However, the results regarding the accuracy of this technology are conflicting.

Inclusion criteria

• Are 19 - 40 years old
• Understand written and oral English
• Are greater than 37 weeks gestational age
• Have a singleton pregnancy

Exclusion criteria

• Have a laboratory Hb less than 100 g/L
• Have abnormal Hb disorders
• Have hyperbilirubinemia
• Have a peripheral vascular disease (e.g. Reynaud's syndrome)
• Have long or acrylic nails