gms | German Medical Science

Background: Neonatal cardiac screening (NCS) including pulse oximetry is standard practice in OECD countries, but has not been broadly implemented for the world’s very high altitude births (>11,483 feet (>3,500 meters) above sea level). The population living at very high altitudes is approximately 14.4 million, with China, Peru, and Bolivia having the highest absolute populations. Bolivia has the highest percentual population above 3,500 msl. (32.5%). Research has shown that birth at very high altitudes can increase the risk of heart defects in newborns at least by a factor of 2. The implementation of NCS poses greater challenges in higher altitude regions, both due to lower oxygen saturations among neonates in the first 24 hours of life, as well as lack of training resources and fragile information systems for patient referral.

Objectives:

1.

To better understand the potential impact of NCS in reduction of newborn mortality at very high altitude: Therefore, we aim to determine the prevalence of congenital heart diseases (CHD) + the prevalence of pulmonary hypertension at very high altitude in Bolivia. Bolivia has the 2^nd highest newborn mortality in Latin America, where CHD are among the most relevant causes. Newborns leave wards without undergoing a standardized screening protocol for CHD and pulmonary hypertension.

2.

To define a cut-off for pulse oximetry screenings: Screening capacities within the Bolivian healthcare workforce are limited, due to lack of training and equipment.

3.

To develop effective protocols for case detection and false positive screening limitation: In Bolivia, only one single facility in the public healthcare system is equipped to fully diagnose (via echocardiography) and treat children with CHD: Hospital Del Niño La Paz.

Methods: This study included all infants born at Hospital Holandes (4,150 meters above sea level (13,615 feet)), or transferred before 48 hours of life between December 2020 and January 2022. The sample of 1,009 newborns was randomized and reflected 20% of all infants born at the ward. Consented mothers completed a structured interview, and clinical information about the infant was collected.

Pulse oximetry was performed by a trained member of the In-house medical personnel on both left foot and arm on newborn between 24 and 48 h of age. All infants underwent an established screening echocardiogram protocol within 48 hours after birth by a Paediatric Cardiologist of Kardiozentrum.

Results: Among 1009 newborns, 50 patients had relevant CHD (4.96%). The most frequent diagnosis was VSD (40.8%), ASD (25.9%), PDA (16.9%). 69 patients (6.8%) were found with pulmonary hypertension, 6 patients (0.6%) with persistence of fetal circulation were identified.

The mean SpO2 in the right hand among healthy newborns was 90% (ranging from 84 to 99). At 83% oxygen saturation, the false positive rate was 20%. 623 patients had no relevant findings.

Conclusions: The study identified relevant CHD in 4.9% of the patient cohort, significantly exceeding the prevalence reported in the literature for low-altitude populations. 69 patients showed prolonged postnatal adaptation with oxygen therapy dependency and an enhanced risk of sudden infant death, indicating considerable risk of death without intervention. Therefore, implementing a standardized clinical examination protocol and pulse oximetry measurements is likely to reduce newborn mortality in Bolivia, and shall be included in the national norms for universal newborn screening protocols.

Next steps: Campaign for a law on universal neonatal cardiac screening, sensitive to altitude; Integrate neonatal cardiac screening into routine triage programs and digital patient records; Research concerning genetic expression and pathways related to populations at high altitude; Testing autonomous, hands-free ultrasound scans with AI-driven onboard image interpretation for real time decision support.