Major cardiorespiratory events do not increase after immunizations, eye exams, and other stressors in most very low birth weight infants

Sullivan, B. A., Ahmad, S. M., Slevin, C. C., Sinkin, R. A., Nagraj, V. P., Fairchild, K. D. | JNPM 2022;

Abstract: BACKGROUND: Increased cardiorespiratory events with bradycardia and oxygen desaturation have been reported in very low birthweight (VLBW) infants following stressors such as immunizations. These events are difficult to quantify and may be mild. Our group developed an automated algorithm to analyze bedside monitor data from NICU patients for events with bradycardia and prolonged oxygen desaturation (BDs) and used this to compare BDs 24 hours before and after potentially stressful interventions. METHODS: We included VLBW infants from 2012–2017 with data available around at least one of four interventions: two-month immunizations, retinopathy of prematurity (ROP) examinations, ROP therapy, and inguinal hernia surgery. We used a validated algorithm to analyze electrocardiogram heart rate and pulse oximeter saturation data (HR, SpO2) to quantify BD events of HR < 100 beats/minute for≥4 seconds with oxygen desaturation < 80%SpO2 for≥10 seconds. BDs were analyzed 24 hours before and after interventions using Wilcoxon rank-sum tests. RESULTS: In 354 of 493 (72%) interventions, BD frequency stayed the same or decreased in the 24 hours after the event. An increase of at least five BD’s occurred in 17/146 (12%) after immunizations, 85/290 (29%) after ROP examinations, 4/33 (12%) after ROP therapy, and 3/25 (12%) after hernia surgery. Infants with an increase in BDs after interventions had similar demographics compared to those without. More infants with an increase in BDs following immunizations were on CPAP or caffeine than those without. CONCLUSIONS: Most VLBW infants in our cohort had no increase in significant cardiorespiratory events in the 24 hours following potentially stressful interventions.

*Corresponding Author: 

Brynne A. Sullivan, MD, MSc, University of Virginia, Pediatrics, PO Box 800386, Charlottesville, 22908-0386, VA, USA. Tel.: +1 434 924 5428; Fax: +1 434 924 2816; E-mail: