Accuracy of a portable pulse oximeter in monitoring hypoxemic infants with cyanotic heart disease

Abstract

Objective: Infants with single ventricle physiology have arterial oxygen saturations between 75 and 85%. Home monitoring with daily pulse oximetry is associated with improved interstage survival. They are typically sent home with expensive, bulky, hospital-grade pulse oximeters. This study evaluates the accuracy of both the currently used Masimo LNCS and a relatively inexpensive, portable, and equipped with Bluetooth technology study device, by comparing with the gold standard co-oximeter.

Design: Prospective, observational study.

Setting: Single institution, paediatric cardiac critical care unit, and neonatal ICU.

Interventions: none.

Patients: Twenty-four infants under 12 months of age with baseline oxygen saturation less than 90% due to cyanotic CHD.

Measurements and results: Pulse oximetry with WristOx2 3150 with infant sensors 8008 J (study device) and Masimo LCNS saturation sensor connected to a Philips monitor (hospital device) were measured simultaneously and compared to arterial oxy-haemoglobin saturation measured by co-oximetry. Statistical analysis evaluated the performances of each and compared to co-oximetry with Schuirmann's TOST equivalence tests, with equivalence defined as an absolute difference of 5% saturation or less. Neither the study nor the hospital device met the predefined standard for equivalence when compared with co-oximetry. The study device reading was on average 4.0% higher than the co-oximeter, failing to show statistical equivalence (p = 0.16). The hospital device was 7.4% higher than the co-oximeter and also did not meet the predefined standard for equivalence (p = 0.97).

Conclusion: Both devices tended to overestimate oxygen saturation in this patient population when compared to the gold standard, co-oximetry. The study device is at least as accurate as the hospital device and offers the advantage of being more portable with Bluetooth technology that allows reliable, efficient data transmission. Currently FDA-approved, smaller portable pulse oximeters can be considered for use in home monitoring programmes.

Keywords: Pulse oximetry; congenital heart disease/defects; home monitoring; hypoxia; monitoring; paediatric.