Serum cortisol values, superior vena cava flow and illness severity scores in very low birth weight infants

Abstract

Objective: Recent evidence suggests that high cortisol concentrations are associated with increased morbidity and mortality in very low birth weight (VLBW) infants. Neonatal illness severity and mortality risk scores are reliable in predicting morbidity and mortality. The objectives were (i) to assess the correlation between serum cortisol levels and clinical assessment of multi-organ dysfunction/illness severity scores (CRIB II, SNAPPE-II and neonatal multiple organ dysfunction score (NEOMOD)) in first 24 h in VLBW infants and (ii) to assess the relationship between surrogates of end organ blood flow and serum cortisol levels.Study Design: A prospective observational cohort study. Neonates with birth weight <1500 g were eligible for enrollment. Echocardiography evaluation of superior vena cava (SVC) flow was carried out in the first 24 h life. Cortisol levels were measured simultaneously and appropriate clinical scores were calculated.Result: A total of 54 VLBW neonates were enrolled following parental consent. Two patients were excluded because of congenital malformations. In 14 babies the cortisol value was not simultaneously obtained. The mean birth weight was 1.08 kg, mean gestational age was 27.8 weeks. There was a significant correlation between cortisol and NEOMOD score (P ¼ 0.006). There was no correlation between cortisol and CRIB II score (P ¼ 0.34), SVC flow (P ¼ 0.49) and mean arterial blood pressure respectively (P ¼ 0.35). Conclusion:There was no correlation between SVC flow and cortisol values or between cortisol and mean blood pressure values. There was a significant correlation between cortisol levels and neonatal organ dysfunction score evaluated suggesting that stressed VLBW infants do mount a cortisol response. Keywords: VLBW; neonate; cortisol; superior vena cava; blood pressure; illness severity score IntroductionThe immediate postnatal period in very low birth weight (VLBW) infants is frequently complicated by hypotension and low end-organ flow. Superior vena cava (SVC) flow has proven to be a useful marker of systemic blood flow, 1 but is not easily obtained at the bedside. Blood pressure values are readily available at the bedside and hypotension has been associated with adverse short-term and long-term outcome.2,3 A number recent studies have focused on evaluating the role of hydrocortisone therapy in hypotension and suspected adrenocortical insufficiency in the sick preterm infants during the early course of life.

A Systematic Review

“…It has been used internationally in countries including: United States of America (USA), 15–19 Canada, 20–32 Spain, 33–35 Italy, 36,37 Brazil, 12,38 India, 39,40 France, 41 Thailand, 42 Netherlands, 43 Ireland, 44 China, 45 and Iran 46 . Two studies had cohorts that were derived from populations across two countries including the USA and Canada.…”

Stress and severity of illness in very low birth weight infants: what are we measuring?

“…Interestingly, the NEOMOD score, which evaluates organ dysfunction, was the only marker of severity of illness that correlated with elevated cortisol concentrations. 1 The growing body of information suggests that measuring cortisol concentrations is not helpful in identifying infants with relative adrenal insufficiency that would benefit from supplementation with hydrocortisone. Clinical symptoms, with lack of response to vasopressor therapy, continue to be the indication for the need for treatment with hydrocortisone, regardless of whether the cortisol value is high or low.…”

“…16 There is a growing concern regarding the clinical implication of high cortisol values in the VLBW population. 1,7,15,16 The subset of critically ill infants who show an exaggerated response to stress has been associated with increased adverse outcomes, specifically spontaneous gastrointestinal perforations, 15 intraventricular hemorrhage, periventricular leukomalacia and death. 16 These adverse outcomes are not associated with the use of hydrocortisone, rather with the innate response of these infants.…”

“…Miletin et al 1 evaluated the contribution of cortisol concentrations in interpreting the severity of illness in this high-risk population. Early cortisol concentrations (12-24 h of life) were obtained, and compared with a variety of measures of severity of illness, including CRIB II, SNAPPE-II and NEOMOD, as well as the clinical measures of perfusion assessed by echocardiography: mean blood pressure and superior vena cava (SVC) flow.…”

“…1 Cortisol values have been examined by a number of investigators in an attempt to identify infants with relative adrenal insufficiency. As these infants are at high risk for hypotension, echocardiographic measures were used to identify cardiovascular instability, which may be a component of relative adrenal insufficiency.…”