Hemodynamic correlates of serum cortisol in neonates after cardiopulmonary bypass

Critical Illness-Related Corticosteroid Insufficiency (CIRCI) After Pediatric Cardiac Surgery

Although current studies do not support the routine use of corticosteroids after cardiopulmonary bypass in pediatric patients, there is incomplete understanding of the potential hemodynamic contribution of postoperative critical illness-related corticosteroid insufficiency in the intensive care unit. By reviewing the available studies and underlying pathophysiology of these phenomena in critically ill neonates, we can identify a subset of patients that may benefit from optimal diagnosis and treatment of receiving postoperative steroids. A suggested algorithm used at our institution is provided as a guideline for treatment of this high-risk population.

Adrenal insufficiency in neonates undergoing cardiopulmonary bypass and postoperative hypothalamic-pituitary-adrenal function after prophylactic glucocorticoids

OBJECTIVES

Determine incidence of preoperative adrenal insufficiency in neonates >35 weeks gestation with congenital heart disease undergoing cardiothoracic surgery with bypass and effects of prophylactic methylprednisolone on postoperative hypothalamic-pituitary-adrenal function and hemodynamic stability.

DESIGN

Prospective observational study in 36 neonates with preoperative adrenocorticotrophic hormone stimulation tests and serial total cortisol and adrenocorticotrophic hormone measurements before and after surgery. Data analyses: analysis of variance and regression.

RESULTS

Baseline circulating adrenocorticotrophic hormone and cortisol were unchanged 4-20 days postnatal (P > 0.1); however, cortisol levels rose with increasing adrenocorticotrophic hormone, P = 0.02. Ten neonates (29%) demonstrated preoperative adrenal insufficiency (∆cortisol ≤9 µg/dl); one had postoperative hemodynamic instability. Growth-restricted neonates had lower baseline cortisol, but normal stimulation tests and responded well to surgical stresses. Seventy-five percent of neonates receiving perioperative methylprednisolone demonstrated postoperative hypothalamic-pituitary-adrenal inhibition.

CONCLUSION

Adrenal insufficiency appears common in neonates >35 weeks gestation with congenital heart disease, but did not contribute to postoperative hemodynamic instability despite hypothalamic-pituitary-adrenal inhibition.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.

Corticosteroids in Pediatric Heart Surgery: Myth or Reality

Background: Corticosteroids have been administered prophylactically for more than 60 years in pediatric heart surgery, however, their use remains a matter of debate. There are three main indications for corticosteroid use in pediatric heart surgery with the use of cardiopulmonary bypass (CPB): (1) to blunt the systemic inflammatory response (SIRS) induced by the extracorporeal circuit; (2) to provide perioperative supplementation for presumed relative adrenal insufficiency; (3) for the presumed neuroprotective effect during deep hypothermic circulatory arrest operations. This review discusses the current evidence behind the use of corticosteroids in these three overlapping areas. Materials and Methods: We conducted a structured research of the literature using PubMed and MEDLINE databases to November 2017 and additional articles were identified by cross-referencing. Results: The evidence suggests that there is no correlation between the effect of corticosteroids on inflammation and their effect on clinical outcome. Due to the limitations of the available evidence, it remains unclear if corticosteroids have an impact on early post-operative outcomes or if there are any long-term effects. There is a limited understanding of the hypothalamic-pituitary-adrenal axis function during cardiac surgery in children. The neuroprotective effect of corticosteroids during deep hypothermic circulatory arrest surgery is controversial. Conclusions: The utility of steroid administration for pediatric heart surgery with the use of CPB remains a matter of debate. The effect on early and late outcomes requires clarification with a large multicenter randomized trial. More research into the understanding of the adrenal response to surgery in children and the effect of corticosteroids on brain injury is warranted.

Long-term Associations of an Early Corrected Ventricular Septal Defect and Stress Systems of Child and Mother at Primary School Age

INTRODUCTION

Ventricular septal defect (VSD) is the most common congenital heart defect, with larger VSDs typically being corrected with an open-heart surgery during infancy. Long-term consequences of a VSD-corrective surgery on stress systems of child and mother are still unknown. The aim of the present study is to investigate the associations of an early corrected VSD and diurnal cortisol release of child and mother.

METHODS

26 children (12 boys) between 6 and 9 years old, who underwent surgery for an isolated VSD within the first 3 years of life, and their mothers participated in the study. Their diurnal cortisol profiles were compared to a sex-, age-, and socioeconomic status-matched healthy control group. Within the VSD group, associations between cortisol and characteristics of surgery and hospitalization were investigated. Child and mother psychopathological symptoms were considered as a possible interfering mechanism of altered cortisol profiles.

RESULTS

Diurnal cortisol profiles of children with an early corrected VSD did not differ from those of controls. However, mothers of affected children exhibited higher cortisol levels in the morning (p < 0.001, [Formula: see text]) and a steeper diurnal cortisol slope (p = 0.016, [Formula: see text]) than mothers of healthy children.

CONCLUSION

Results indicate a favorable development of children with an early corrected VSD, in terms of comparable diurnal cortisol profiles with healthy controls, according to a comparable mother-rated psychopathology. Mothers of affected children reveal altered diurnal cortisol levels, without differences in self-rated psychopathology. This divergence should be clarified in future research.

Adrenal insufficiency in neonates after cardiac surgery with cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass (CPB) may lead to adrenal insufficiency (AI). Emerging evidence supports association of AI with morbidity after cardiac surgery.

AIMS

The aim of this study was to define AI incidence in neonates undergoing complex cardiac surgery with CPB and its association with intraoperative post-CPB outcomes.

METHODS

Forty subjects enrolled in a prior randomized control trial who received preoperative methylprednisolone as part of our institutional neonatal bypass protocol were included. No intraoperative steroids were given. ACTH stimulation tests were performed: preoperatively and 1 h after separation from CPB. AI was defined as <9 μg·ml^-1 increase in cortisol at 30 min post cosyntropin 1 mcg. Clinical outcomes were collected up to 90 min after CPB.

RESULTS

2/40 (5%) subjects had preoperative AI vs 13/40 (32.5%) post-CPB AI, P ≤ 0.001. No significant difference was observed in age, gestational age, weight, CPB time, circulatory arrest, or STAT category between subjects with or without post-CPB AI. ACTH decreased from preoperative values 127.3 vs 35 pcg·ml^-1 [median difference = 81.8, 95% CI = 22.7-127.3], while cortisol increased from 18.9 vs 75 μg·dl^-1 [median difference = 52.2, 95% CI = 36.3-70.9]. Post-CPB AI was associated with increased median colloid resuscitation, 275 vs 119 ml·kg^-1 [median difference = 97.8, 95% CI = 7.1-202.2]; higher median peak lactate, 9.4 vs 6.9 mg·dl^-1 [median difference = 3.2, 95% CI = 0.04-6.7]; median post-CPB lactate, 7.9 vs 4.3 mg·dl^-1 , [median difference 3.6, 95% CI = 2.1-4.7], and median lactate on admission to CICU, 9.4 vs 6.0 mg·dl^-1 [median difference = 3, 95% CI = 1.1-4.9]. No difference was observed in blood pressure or vasoactive inotrope score at any time point measured in operating room (OR). Higher initial post-CPB cortisol correlated with decreased cosyntropin response.

CONCLUSIONS

Neonatal cardiac surgery with CPB and preoperative methylprednisolone leads to AI as determined by low-dose ACTH stimulation test in one-third of patients. AI is associated with increased serum lactate and colloid resuscitation in OR. Impact of preoperative methylprednisolone on results is not defined. Benefit of postoperative steroid administration in neonates with post-CPB AI warrants further investigation.

Total and free cortisol responses and their relation to outcomes after cardiopulmonary bypass in infants

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA) axis dysfunction may be partially responsible for the hemodynamic instability experienced by infants after cardiopulmonary bypass (CPB). We report the full spectrum of the HPA response surrounding CPB for infant congenital cardiac surgery.

METHODS

We enrolled 84 infants who received 1 mg/kg of dexamethasone before initiation of CPB. Total cortisol (TC), free cortisol (FC), adrenocorticotropic hormone (ACTH), and corticosteroid-binding globulin (CBG) were measured at 3 time points: immediately before CPB (TP1), on intensive care unit arrival (TP2), and at 24 hours after surgery (TP3). A 1-μg ACTH stimulation test was performed at each time point to evaluate adrenal responsiveness.

RESULTS

Sixty-eight infants completed all study procedures. Levels of TC, FC, CBG, and ACTH decreased significantly between the preoperative and 24-hour postoperative measurements. There were no significant associations between preoperative FC responses and clinical outcomes after adjusting for weight and Risk-Adjusted Scores for Congenital Heart Surgery. Infants with subnormal TC responses to ACTH stimulation (<9 μg/dL) at TP2 had greater fluid requirements (P < .001) and greater chest tube output (P < .001) during the first 24 hours, as well as longer length of stay (LOS) (P = .007). Except for LOS, these differences persisted for infants with subnormal stimulation tests at TP3.

CONCLUSIONS

We observed a significant decline in all aspects of the HPA axis throughout the first 24 hours after infant CPB. TC and FC levels were not associated with clinical outcomes. Subnormal (Δ <9 μg/dL) TC response to cosyntropin stimulation during the postoperative period was associated with increased fluid resuscitation and greater LOS.

Postoperative Hydrocortisone Infusion Reduces the Prevalence of Low Cardiac Output Syndrome After Neonatal Cardiopulmonary Bypass

OBJECTIVE

Neonatal cardiac surgery with cardiopulmonary bypass is often complicated by morbidity associated with inflammation and low cardiac output syndrome. Hydrocortisone "stress dosing" is reported to provide hemodynamic benefits in some patients with refractory shock. Development of cardiopulmonary bypass-induced adrenal insufficiency may provide further rationale for postoperative hydrocortisone administration. We sought to determine whether prophylactic, postoperative hydrocortisone infusion could decrease prevalence of low cardiac output syndrome after neonatal cardiac surgery with cardiopulmonary bypass.

DESIGN

Double-blind, randomized control trial.

SETTING

Pediatric cardiac ICU and operating room in tertiary care center.

PATIENTS

Forty neonates undergoing cardiac surgery with cardiopulmonary bypass were randomized (19 hydrocortisone and 21 placebo). Demographics and known risk factors were similar between groups.

INTERVENTIONS

After cardiopulmonary bypass separation, bolus hydrocortisone (50 mg/m²) or placebo was administered, followed by continuous hydrocortisone infusion (50 mg/m²/d) or placebo tapered over 5 days. Adrenocorticotropic hormone stimulation testing (1 μg) was performed before and after cardiopulmonary bypass, prior to steroid administration. Blood was collected for cytokine analysis before and after cardiopulmonary bypass.

MEASUREMENTS AND MAIN RESULTS

Subjects receiving hydrocortisone were less likely to develop low cardiac output syndrome (5/19, 26% vs 12/21, 57%; p = 0.049). Hydrocortisone group had more negative net fluid balance at 48 hours (-114 vs -64 mL/kg; p = 0.01) and greater urine output at 0-24 hours (2.7 vs 1.2 mL/kg/hr; p = 0.03). Hydrocortisone group weaned off catecholamines and vasopressin sooner than placebo, with a difference in inotrope-free subjects apparent after 48 hours (p = 0.033). Five placebo subjects (24%) compared with no hydrocortisone subjects required rescue steroids (p = 0.02). Thirteen (32.5%) had adrenal insufficiency after cardiopulmonary bypass. Patients with adrenal insufficiency randomized to receive hydrocortisone had lower prevalence of low cardiac output syndrome compared with patients with adrenal insufficiency randomized to placebo (1/6 vs 6/7, respectively; p = 0.02). Hydrocortisone significantly reduced proinflammatory cytokines. Ventilator-free days, hospital length of stay, and kidney injury were similar.

CONCLUSIONS

Prophylactic, postoperative hydrocortisone reduces low cardiac output syndrome, improves fluid balance and urine output, and attenuates inflammation after neonatal cardiopulmonary bypass surgery. Further studies are necessary to show if these benefits lead to improvements in more important clinical outcomes.

Serum cortisol and early postoperative outcome after stage-1 palliation for hypoplastic left heart syndrome

OBJECTIVES

The postoperative cortisol profile and its association with early outcomes are poorly understood in neonates undergoing surgery for complex congenital heart disease. We investigated the postoperative profile of cortisol and its relationship with the clinical course in a cohort of newborns after stage-1 palliation for hypoplastic left heart syndrome.

DESIGN

Prospective observational study.

SETTING

Pediatric cardiovascular ICU at a tertiary children's hospital.

SUBJECTS

Twenty-three neonates after stage-1 palliation for hypoplastic left heart syndrome between 2009 and 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Three serial measurements of total serum cortisol after surgery. The first measurement was taken immediately after surgery and the second and third-on the first and second postoperative mornings. The median weight of the infants was 3.0 kg (2.7-3.4 kg), and the age at surgery was 7 days (6-9 d). The median (25th-75th percentile) cortisol levels at admission, day 1, and day 2 were 96.2 μg/dL (51.1-112 μg/dL), 17.3 μg/dL (9.7-25.1 μg/dL), and 10 μg/dL (6.5-17 μg/dL), respectively (p < 0.0001 between admission and day 1). Higher cortisol was associated with greater morbidity, including the need for preoperative ventilation, increased total duration of ventilation, duration of inotropic support, and hospital length of stay.

CONCLUSIONS

Cortisol levels fell significantly over the first 24 hours after stage-1 palliation for hypoplastic left heart syndrome. A higher postoperative cortisol was associated with increased postoperative morbidity, which warrants further investigation.

Dexamethasone levels predict cortisol response after infant cardiopulmonary bypass

OBJECTIVES

We sought to evaluate whether there is variability in blood dexamethasone levels after a standard 1 mg/kg dose of dexamethasone administered before infant cardiopulmonary bypass. We hypothesized that postoperative dexamethasone drug levels are highly variable, and that the infant stress response is related inversely to the amount of dexamethasone measured in the blood.

METHODS

Thirty-two infants (age, ≤365 days) received 1 mg/kg of dexamethasone before cardiopulmonary bypass (CPB) initiation. Blood was analyzed for cortisol, adrenocorticotropin, and interleukin (IL)-6, IL-8, and IL-10 levels after anesthesia induction, after CPB, after intensive care unit (ICU) arrival, and 4, 8, 12, and 24 hours after surgery. Patients were grouped as high dexamethasone (≥15 μg/dL) or low dexamethasone (<15 μg/dL) based on their level at ICU arrival.

RESULTS

Dexamethasone levels varied significantly between the high (n = 22) and low (n = 10) dexamethasone groups throughout the entire postoperative course and were correlated highly with cortisol response. Patients with high dexamethasone levels had postoperative cortisol levels that were lower than their pre-CPB baseline cortisol levels. Cortisol levels remained low throughout the first 24 postoperative hours even after dexamethasone levels neared zero. There were no significant differences between groups in the duration of mechanical ventilation or ICU length of stay.

CONCLUSIONS

Dexamethasone levels are highly variable at ICU arrival, despite standardized 1 mg/kg dosing before CPB initiation.

Postoperative serum cortisol concentration and adrenal insufficiency in neonates undergoing open-heart surgery

BACKGROUND

We sought to determine whether immediate postoperative serum cortisol concentration predicts adrenal insufficiency in neonates after cardiac surgery with cardiopulmonary bypass. We hypothesized that cortisol <10 µg/dL would be associated with increased catecholamine requirements and fluid resuscitation and would predict hemodynamic responsiveness to exogenous steroids.

METHODS

Retrospective study of 41 neonates was carried out for the levels of cortisol in the immediate postoperative period; of whom, 15 received steroids due to high levels of inotropic support. Laboratory and clinical outcomes were collected.

RESULTS

Median cortisol was 12 µg/dL (interquartile range: 5.2-27.4). Levels of cortisol <10 µg/dL was not associated with any clinical variable indicative of increased illness severity. Peak lactate (9.1 vs 11.8 mmol/L, P = .04) and maximum arteriovenous saturation difference ([Sao 2 - Svo 2] 28% vs 32%, P = .05) were both lower among patients with levels of cortisol <10 µg/dL. Six (40%) patients had a significant hemodynamic improvement within 24 hours after receiving steroids (responders), although there was no statistical difference between levels of cortisol in responders versus nonresponders. Level of cortisol was positively correlated with maximum lactate (P < .001), maximum Sao 2 - Svo 2 (P < .001), maximum inotrope score (P = .014), initial 24-hour fluid intake (P = .012), and time to negative fluid balance (P = .008) and was negatively correlated with initial 24-hour urine output (P < .001).

CONCLUSIONS

Low cortisol obtained in the immediate postoperative period is not associated with worse postoperative outcomes or predictive of steroid responsiveness. In contrast, elevated levels of cortisol are positively correlated with severity of illness. The use of an absolute cortisol threshold to identify adrenal insufficiency and/or guide steroid therapy in neonates after cardiac surgery is unjustified.

Adrenocortical function in the postoperative pediatric cardiac surgical patient

PURPOSE OF REVIEW

Corticosteroids are frequently used in the postoperative care of children with congenital heart disease. This review describes the function of the adrenocortical axis in this population and the effects of corticosteroids on cardiovascular function. In addition, it examines the diagnosis of adrenal insufficiency in this population and provides an overview of recent studies on the use of steroids in treating hemodynamic instability in these children.

RECENT FINDINGS

Corticosteroids improve hemodynamic parameters in children with shock following congenital heart surgery. This improvement may be due to treatment of adrenal insufficiency or from direct cardiovascular effects of corticosteroids. The diagnosis of adrenal insufficiency in this population is challenging as low cortisol levels do not consistently correlate with adverse outcomes.

SUMMARY

Because of the lack of evidence delineating what the normal adrenocortical function is in this population, cortisol levels alone are not sufficient to justify treating with steroids in this population. Corticosteroids are beneficial in improving hemodynamics in children with shock after congenital heart surgery, but the adverse effects of the therapy in this context are not fully known. Prospective trials are necessary to clarify which patients may benefit from steroid therapy and to examine long-term effects of steroids.