Investigation of the effect of adding perfusion index to the screening of congenital heart disease in asymptomatic newborns by pulse oximetry method

Investigation of the effect of adding perfusion index to the screening of congenital heart disease in asymptomatic newborns by pulse oximetry method. Introduction and Aim: The incidence of congenital heart disease (CHD) in newborns is 0.8-1% on average. CHD has difficulties in both antenatal and postnatal diagnosis. Successful and early correction surgeries are possible today thanks to early diagnosis in those born with CHD. This contributes to both morbidity and mortality. However, a method with high sensitivity and selectivity for CHD screening has not been found yet. Our study aimed to increase sensitivity and specificity by adding perfusion index to pulse oximetry screening for CHD screening. Materials and methods: In this retroprospective study, 32422 newborns who were followed up with their mothers after delivery at Ankara City Hospital were included. Preductal and postductal saturation (SpO2) and perfusion index (PI) of each baby were measured by both methods. Positive screening criteria were defined as postductal oxygen saturation (SpO2) below 95%, difference between preductal and postductal SpO2 greater than 3%, or a PI value below 0.7. Confirmed positive cases underwent echocardiography for definitive diagnosis. Sensitivity, specificity, positive and negative predictive values were calculated using appropriate statistical methods with the data. Results: Of the 32422 newborns included in the study, 16396 (50.3%) were female and 16026 (49.4%) were male. 30383 (93.7%) of the newborns were term, 2039 (16.3%) were preterm. The gestational week was between 34 weeks and 42 weeks; mean 38.5 (± 1.39 SD) weeks. The birth weight of the cases was between 1830 g and 5000 g; The mean was 3259 (± 436.30 SD) gr. The mean preductal SpO2 of the newborns was 97.75 (±1.68 SD), the mean postductal SpO2 was 97.6 (±1.77 SD), the mean preductal PI was calculated as 2.10 (±1.01 SD). Postductal PI was calculated as 2.0 (±0.98 SD). Pulse oximetry scan was evaluated as positive in 283 of all cases. According to the ECO result, cardiac pathology was detected in 236 of them. No cardiac pathology was detected in 47 patients. 276 people were found to be positive for PI screening. According to the ECO result, cardiac pathology was detected in 37 of them. No cardiac pathology was detected in 5 of them. The sensitivity of pulse oximetry alone is 85.5%, and when pulse oximetry is used together with PI, the sensitivity increases to 94.2%. False positivity of 0.1% for pulse oximetry. False positivity for PI was calculated as 0.02%, false positivity was calculated as 0.2% when the two methods were used together. It causes an approximately 2-fold increase in false positives when used together. False negative 14.5% for pulse oximetry. False negativity for PI is 86.6%, and false negativity regresses to 5.6% when the two methods are used together. 7 pulmonary atresia cases from CCHD were detected jointly by both methods. Only PI diagnosed 1 Aortic Coarctation case. 3 CCHDs that both methods survive are 1 hypoplastic left heart, 1 tetralogy of fallot, 1 aortic coarctation. Conclusions: Our results show that the use of pulse oximetry and perfusion index measurement in congenital heart disease (CHD) screening may be beneficial, but the combined use of the two methods is more successful in catching different patient groups. More studies are needed on this subject in large populations. Keywords: pulse oximetry, perfusion index, newborn, congenital heart diseases