BP Readings Add Nothing to Pulse Oximetry Screening



MADISON, WIS. – Adding blood pressure readings to pulse oximetry screening prompted additional testing and failed to identify any newborns with critical congenital heart disease in a retrospective analysis of 10,012 infants.

In all, 84% of infants who failed the initial heart disease screening, failed based on blood pressure (BP) measurements alone.

Twelve of the 13 infants with positive screens had positive BP measurements, which resulted in 6 echocardiograms being performed that likely would not otherwise have been done, Dr. Kristi Boelke reported at the annual meeting of the Midwest Society for Pediatric Research.

Pulse oximetry screening can identify infants with asymptomatic critical congenital heart disease (CCHD) before they are discharged home, but it is not currently included in most state newborn screening panels. Congenital heart defects account for 24% of birth defect–related infant deaths in the United States, according to the Department of Health and Human Services.

To date, no studies have evaluated BP measurements as a screening tool for CCHD, according to Dr. Boelke, a neonatology fellow at the University of Wisconsin, Madison.

Dr. Boelke and her colleagues reviewed the charts for pulse oximetry and BP screening results for all infants born at more than 34 6/7 weeks’ gestation at Meriter Hospital in Madison, Wis., between Feb. 12, 2008, and Dec. 31, 2010. Charts at three hospitals providing pediatric care in the area also were reviewed for infants seen in the emergency department or readmitted with a diagnosis of any congenital heart disease at less than 30 days of age, and compared with the newborn Meriter data.

Screening was completed at 24 hours of age or prior to discharge, if discharge occurred before 24 hours. Pulse oximetry was done on a lower extremity, with oxygen saturation of less than 95% considered positive. BP was measured on the right upper extremity and one of the lower extremities, and considered positive if the systolic pressure in the right arm was 15 mm Hg more than the systolic pressure in either lower extremity.

In all, 127 infants failed the BP screening, 23 failed the pulse oximetry screening, and 1 failed both screens, Dr. Boelke reported in a poster presentation.

After repeat screening within 2 hours, 12 infants failed the BP screening and 1 failed both screens. Seven of the 13 infants had an echocardiogram performed, and none of these infants had CCHD. This resulted in a false-positive rate for the BP screen of 0.13%, with almost all of the false positives due to the BP portion of the screening, she noted. Specificity of the screening was 99.9%, and negative predictive value was 100%.

The echocardiogram results were one small ventricular septal defect, one small patent ductus arteriosus (PDA), one small atrial septal defect and PDA, and four structurally normal hearts.

A chart review of the three local hospitals revealed no infants who had been discharged with unrecognized CCHD.

"Blood pressure measurements created more additional testing, including repeat blood pressure measurements, additional physician and nurse evaluation of the infant, and echocardiograms than pulse oximetry testing," the authors wrote. "This additional testing was of no clinical benefit to the infants as it did not identify any infants with unrecognized CCHD."

The authors noted that BP measurements were sometimes repeated several times on one infant because of the difficulty of obtaining accurate measurements in infants, and that the additional testing sparked by the BP screen also likely created unnecessary anxiety for families.

The Meriter Hospital health information department compiled the data for the analysis. The authors reported no relevant financial conflicts.

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