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Measuring Cardiac Autonomic Nervous System ANS Activity in Children

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Published on: April 29, 2013

The Peacock study: feasibility of the dynamic characterisation of the paediatric hypothalamic-pituitary-adrenal

Daniel Paul Fudulu^1,2, Gianni Davide Angelini³, Fani Fanoula Papadopoulou⁴

¹Department of Cardiac Surgery, Bristol Heart Institute, Bristol, UK. danielfudulu@gmail.com.

BMC Cardiovascular Disorders

|May 27, 2020

Insights

This study demonstrates a new method for measuring stress hormone cortisol in children during heart surgery. The automated microdialysis system provides detailed cortisol profiles, proving its feasibility for pediatric adrenal response evaluation.

Area of Science:

Pediatric Endocrinology
Surgical Physiology
Stress Response

Background:

Limited understanding of the hypothalamic-pituitary-adrenal axis in children undergoing cardiopulmonary bypass.
Challenges in frequent cortisol sampling in pediatric patients, especially neonates.
Lack of consensus on perioperative glucocorticoid use in pediatric cardiac surgery.

Purpose of the Study:

To characterize hypothalamic-pituitary-adrenal axis physiology in children undergoing cardiopulmonary bypass.
To correlate detailed cortisol profiles with clinical outcomes in pediatric cardiac surgery.
To demonstrate the feasibility of a novel automated microdialysis system for frequent hormone sampling.

Main Methods:

Prospective, two-centre observational cohort study (Peacock Study) of 78 children.
Utilized an automated 24-h tissue microdialysis system for cortisol and cortisone measurement every 20 minutes.
Measured serum cortisol and adrenocorticotrophic hormone at seven time points for correlation.

Main Results:

Demonstrated the feasibility of automated microdialysis for measuring pediatric adrenal response.
Observed marked increases in tissue cortisol concentrations several hours post-cardiac surgery.
Noted an increased tissue cortisol/cortisone ratio following surgery.

Conclusions:

Automated microdialysis enables dynamic and frequent hormone measurement in children, overcoming limitations of blood volume.
The study provides the first detailed cortisol profile of a child undergoing heart surgery using this novel method.
Further data will elucidate cortisol profile variations based on age, pathology, and procedure type.

Read full analysis

Abstract

Background:

Cortisol is the main stress hormone mobilised during surgery to establish homeostasis. Our current understanding of the hypothalamic-pituitary-adrenal axis physiology in children undergoing cardiopulmonary bypass is very limited due to: (1) very few cortisol time point measurements over long periods (2) difficulties of sampling in low weight babies and (3) the concomitant use of glucocorticoids at anaesthesia induction. This lack of understanding is reflected in a lack of consensus on the utility of glucocorticoids perioperatively in cardiac surgery with the use of cardiopulmonary bypass.

Methods:

The Peacock Study is a prospective, two-centre, observational cohort study of 78 children (undergoing cardiopulmonary bypass procedures and non-surgical procedures - split by age/cyanosis) that aims to characterise in detail the hypothalamic-pituitary-adrenal axis physiology of children using the stress model of paediatric cardiac surgery. Also, we aim to correlate cortisol profiles with clinical outcome data. We herein describe the main study design and report the full cortisol profile of one child undergoing heart surgery, thus proving the feasibility of the method.

Results:

We used an automated, 24-h tissue microdialysis system to measure cortisol and cortisone, every 20 min. We herein report one cortisol profile of a child undergoing heart surgery. Besides, we measured serum cortisol and adrenocorticotrophic hormone at seven-time points for correlation. Tissue concentrations of cortisol increased markedly several hours after the end of surgery. We also noted an increase in the tissue cortisol/cortisone ratio during this response.

Conclusion:

We report for the first time, the use of an automated microdialysis sampling system to evaluate the paediatric adrenal response in children. Changes in cortisol and cortisone could be measured, and the concentration of cortisol in the tissues increased after the end of cardiac surgery. The method has wide application to measure other hormones dynamically and frequently without the limitation of the circulating blood volume. The data from the main study will clarify how these cortisol profiles vary with age, pathology, type of procedure and correlation to clinical outcomes.

Trial Registration:

ISCRTN registry, number: 982586.

Keywords:

Cardiopulmonary bypass Children Glucocorticoids Hypothalamus-pituitary-adrenal axis Paediatric heart surgery

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