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Updated: Aug 18, 2025
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Published on: March 26, 2020
Autonomic measures identify stress, pain, and instability associated with retinopathy of prematurity ophthalmologic
Vivian Onuagu1, Fumiyuki Gardner2, Ajay Soni3
1Department of Neonatology, Mountain View Hospital Las Vegas, Las Vegas, NV, United States.
Insights
Retinopathy of prematurity examinations cause stress, measurable by skin conductance. Lower heart rate variability before exams predicts instability and need for interventions in vulnerable infants.
Area of Science:
- Neonatal ophthalmology
- Autonomic nervous system function
- Physiological monitoring
Background:
- Ophthalmologic examinations for retinopathy of prematurity (ROP) induce significant stress and pain in infants.
- Non-invasive physiological measures like skin conductance (SC) and high frequency heart rate variability (HF-HRV) can quantify infant stress and autonomic responses.
Purpose of the Study:
- To evaluate the utility of SC in detecting sympathetic nervous system activation during ROP examinations.
- To determine if HF-HRV can predict post-examination physiological stability in infants.
Main Methods:
- Prospective, single-center study measuring SC continuously before, during, and after ROP exams.
- Heart rate variability (HRV) measured 24 hours prior to ROP examination.
- Clinical data collected on infant stability (apneas, bradycardias, desaturations) and post-examination interventions.
Main Results:
- SC significantly increased during and after ROP examinations, indicating sympathetic activation.
- Lower HF-HRV 24 hours pre-exam was associated with higher illness acuity and increased need for interventions.
- Reduced parasympathetic tone (lower HF-HRV) predicted greater instability and need for interventions, especially in sicker infants.
Conclusions:
- ROP examinations elicit a substantial and sustained sympathetic response.
- Autonomic imbalance, indicated by low parasympathetic tone, contributes to infant instability and increased intervention needs.
- Findings highlight the physiological impact of ROP exams and identify infants at higher risk for adverse events.
Background:
Retinopathy of prematurity (ROP) ophthalmologic examinations cause stress and pain. Infants' stress and pain can be measured non-invasively using skin conductance (SC) and high frequency heart rate variability (HF-HRV), reflecting sympathetic-mediated sweating and parasympathetic activity, respectively.
Objectives:
To test the utility of SC to detect sympathetic activation during ROP examination, and the contribution of HF-HRV to predict stability post-examination.
Methods:
In this prospective, single center study, we measured SC continuously pre-, during, and post-examination, and HRV at 24 h pre-ROP examination. Clinical data included stability [apneas, bradycardias, and desaturations (A/B/Ds)], and interventions post-examination.
Results:
SC increased 56% above baseline during ROP examination (p = 0.001) and remained elevated post-examination (p = 0.02). Post-hoc analysis showed higher illness acuity, represented by need for respiratory support, was associated with lower HF-HRV at 24 h pre-ROP examination (p = 0.001). Linear regression indicated lower HF-HRV at 24 h pre-examination contributed to the need for higher intervention (i.e., stimulation to breathe, oxygen support) particularly among infants with higher illness acuity [F(1, 15) = 5.05, p = 0.04; β = -1.33, p = 0.04].
Conclusion:
ROP examination induced a 2-fold increase in sympathetic activation which remained above baseline in recovery. Also, we propose that the low parasympathetic tone associated with autonomic imbalance contributes to instability and need for higher intervention to assure stabilization with A/B/D events. Our findings provide insight into the underestimation of adverse events associated with ROP examination and identification of infants who may be more vulnerable to potential sequelae following ROP examinations.
