Treatment of hypotension in newborns

An Update on Pharmacologic Management of Neonatal Hypotension: When, Why, and Which Medication

Anti-hypotensive treatment, which includes dopamine, dobutamine, epinephrine, norepinephrine, milrinone, vasopressin, terlipressin, levosimendan, and glucocorticoids, is a long-established intervention in neonates with arterial hypotension (AH). However, there are still gaps in knowledge and issues that need clarification. The main questions and challenges that neonatologists face relate to the reference ranges of arterial blood pressure in presumably healthy neonates in relation to gestational and postnatal age; the arterial blood pressure level that potentially affects perfusion of critical organs; the incorporation of targeted echocardiography and near-infrared spectroscopy for assessing heart function and cerebral perfusion in clinical practice; the indication, timing, and choice of medication for each individual patient; the limited randomized clinical trials in neonates with sometimes conflicting results; and the sparse data regarding the potential effect of early hypotension or anti-hypotensive medications on long-term neurodevelopment. In this review, after a short review of AH definitions used in neonates and existing data on pathophysiology of AH, we discuss currently available data on pharmacokinetic and hemodynamic effects, as well as the effectiveness and safety of anti-hypotensive medications in neonates. In addition, data on the comparisons between anti-hypotensive medications and current suggestions for the main indications of each medication are discussed.

Evidence-Based Guidelines for Acute Stabilization and Management of Neonates with Persistent Pulmonary Hypertension of the Newborn

Persistent pulmonary hypertension of the newborn, or PPHN, represents a challenging condition associated with high morbidity and mortality. Management is complicated by complex pathophysiology and limited neonatal specific evidence-based literature, leading to a lack of universal contemporary clinical guidelines for the care of these patients. To address this need and to provide consistent high-quality clinical care for this challenging population in our neonatal intensive care unit, we sought to develop a comprehensive clinical guideline for the acute stabilization and management of neonates with PPHN. Utilizing cross-disciplinary expertise and incorporating an extensive literature search to guide best practice, we present an approachable, pragmatic, and clinically relevant guide for the bedside management of acute PPHN. KEY POINTS: · PPHN is associated with several unique diagnoses; the associated pathophysiology is different for each unique diagnosis.. · PPHN is a challenging, dynamic, and labile process for which optimal care requires frequent reassessment.. · Key management goals are adequate tissue oxygen delivery, avoiding harm..

Echocardiography-directed management of hemodynamically unstable neonates in tertiary care hospitals

Background

Hemodynamic instability and inadequate cardiac performance are common in critically ill children. The clinical assessment of hemodynamic status is reliant upon physical examination supported by clinical signs such as heart rate, blood pressure, capillary refill time, and measurement of urine output and serum lactate. Unfortunately, all of these parameters are surrogate markers of cardiovascular well-being, and they provide limited direct information regarding the adequacy of blood flow and tissue perfusion. A bedside point-of-care echocardiography can provide real-time hemodynamic information by assessing cardiac function, loading conditions (preload and afterload), and cardiac output, which makes it an ideal tool for monitoring hemodynamic assessment in neonates and children.

Methods

A prospective cross-section study was carried out on all neonates admitted to the NICU of Cairo University Children’s Hospital (CUCH) during the period from September 2017 through August 2018 in whom manifestations of hemodynamic instability were elected regardless of gestational age, weight, gender, or type of disease.

Results

There is a positive correlation between EF, FS, LVOT, RVOT, LVTI, RVTI, MAPSE, and TAPSE with birth weight. There is a negative correlation between birth weight and either LVO or RVO. In neonates weighted > 1500 g, there is a significant correlation between decreases in longitudinal systolic function of the heart (TAPSE and MAPSE) and either hemodynamic instability or need for echo-directed management, but there is no significant correlation between both in neonates weighted ≤ 1500 g. There is a significant relationship between birth weight and survival “the more the births weight the better survival chance and between complete compliance with ECDM protocol and achieving normal hemodynamic state.”

Conclusions

Decreases in EF, FS, TAPSE, and MAPSE in low birth weight neonates’ ≤ 1500 g are late signs of hemodynamic instability. TAPSE and MAPSE are the earliest parameters noticed to be decreased in hemodynamically unstable neonates > 1500 g even before EF and FS but return to normal values latterly. There is a significant relationship between complete compliance with ECDM protocol and achieving normal hemodynamics. Birth weight of ≤ 1500 g was an independent predictor of mortality regardless of the degree of compliance with the protocol.

Vein of Galen aneurysmal malformation: rationalizing medical management of neonatal heart failure

Neonates who present in high output heart failure secondary to vein of Galen aneurysmal malformation can be difficult to manage medically due to the complex physiology that results from the large shunt through the malformation. Though the cardiac function is often normal, right ventricular dilation, severe pulmonary hypertension, and systemic steal can result in inadequate organ perfusion and shock. This report recommends medical management for stabilization of neonates prior to definitive management with endovascular embolization. IMPACT: Vein of Galen aneurysmal malformation (VGAM) is a rare intracranial arteriovenous malformation, which can present in the neonatal period with high output heart failure. Heart failure secondary to VGAM is often difficult to manage and is associated with high mortality and morbidity. Despite optimal medical management, many patients require urgent endovascular embolization for stabilization of their heart failure. This report offers discrete recommendations that can be used by clinicians as guidelines for the medical management of heart failure in newborns with VGAM.

The Use of Cardiotonic Drugs in Neonates

There is a distinct lack of age-appropriate cardiotonic drugs, and adult derived formulations continue to be administered, without evidence-based knowledge on their dosing, safety, efficacy, and long-term effects. Dopamine remains the most commonly studied and prescribed cardiotonic drug in the neonatal intensive care unit (NICU), but evidence of its effect on endorgan perfusion still remains. Unlike adult and pediatric critical care, there are significant gaps in our knowledge on the use of various cardiotonic drugs in various forms of circulatory failure in the NICU.

Treating Hypotension in Preterm Neonates With Vasoactive Medications

Preterm neonates often have hypotension which may be due to various etiologies. While it is controversial to define hypotension in preterm neonates, various vasoactive medications are commonly used to provide the cardiovascular support to improve the blood pressure, cardiac output, or to treat shock. However, the literature on the systemic and regional hemodynamic effects of these antihypotensive medications in neonates is deficient and incomplete, and cautious translation of findings from other clinical populations and animal studies is required. Based on a literature search on published reports, meta-analytic reviews, and selected abstracts, this review discusses the current available information on pharmacologic actions, clinical effects, and side effects of commonly used antihypotensive medications including dopamine, dobutamine, epinephrine, norepinephrine, vasopressin, and milrinone in preterm neonates.

Cardiovascular Supportive Therapies for Neonates With Asphyxia - A Literature Review of Pre-clinical and Clinical Studies

Asphyxiated neonates often have hypotension, shock, and poor tissue perfusion. Various "inotropic" medications are used to provide cardiovascular support to improve the blood pressure and to treat shock. However, there is incomplete literature on the examination of hemodynamic effects of these medications in asphyxiated neonates, especially in the realm of clinical studies (mostly in late preterm or term populations). Although the extrapolation of findings from animal studies and other clinical populations such as children and adults require caution, it seems appropriate that findings from carefully conducted pre-clinical studies are important in answering some of the fundamental knowledge gaps. Based on a literature search, this review discusses the current available information, from both clinical studies and animal models of neonatal asphyxia, on common medications used to provide hemodynamic support including dopamine, dobutamine, epinephrine, milrinone, norepinephrine, vasopressin, levosimendan, and hydrocortisone.

American College of Critical Care Medicine Clinical Practice Parameters for Hemodynamic Support of Pediatric and Neonatal Septic Shock

OBJECTIVES

The American College of Critical Care Medicine provided 2002 and 2007 guidelines for hemodynamic support of newborn and pediatric septic shock. Provide the 2014 update of the 2007 American College of Critical Care Medicine "Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock."

DESIGN

Society of Critical Care Medicine members were identified from general solicitation at Society of Critical Care Medicine Educational and Scientific Symposia (2006-2014). The PubMed/Medline/Embase literature (2006-14) was searched by the Society of Critical Care Medicine librarian using the keywords: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation, and American College of Critical Care Medicine guidelines in the newborn and pediatric age groups.

MEASUREMENTS AND MAIN RESULTS

The 2002 and 2007 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and American Heart Association/Pediatric Advanced Life Support sanctioned recommendations. The review of new literature highlights two tertiary pediatric centers that implemented quality improvement initiatives to improve early septic shock recognition and first-hour compliance to these guidelines. Improved compliance reduced hospital mortality from 4% to 2%. Analysis of Global Sepsis Initiative data in resource rich developed and developing nations further showed improved hospital mortality with compliance to first-hour and stabilization guideline recommendations.

CONCLUSIONS

The major new recommendation in the 2014 update is consideration of institution-specific use of 1) a "recognition bundle" containing a trigger tool for rapid identification of patients with septic shock, 2) a "resuscitation and stabilization bundle" to help adherence to best practice principles, and 3) a "performance bundle" to identify and overcome perceived barriers to the pursuit of best practice principles.

Glucocorticoid Programming in Very Preterm Birth

Very preterm (i.e., <32 weeks of gestation) infants admitted to the neonatal intensive care unit are compromised in their abilities to respond adequately to common threats like hemodynamic changes and reduced energy supplies, which is partly attributable to adrenocortical insufficiency. Conversely, later in life, these infants show features of increased glucocorticoid bioactivity, such as abdominal fat distribution, raised blood pressure, insulin resistance and diabetes mellitus type 2. It has been suggested that the very preterm newborn responds to the adverse postnatal environment with a sustained elevation in hypothalamus-pituitary-adrenal axis activity that persists beyond infancy. This has implications for subsequent growth, body composition, metabolism, neurodevelopment and, ultimately, long-term disease risk. The mechanisms underpinning these associations are not fully elucidated yet. This review gives a brief summary of studies that investigated adrenocortical function in very preterm newborns and how the axis changes with age, as a possible explanation for the association between prematurity and long-term outcome.

Late-onset circulatory collapse of prematurity

Late-onset circulatory collapse (LCC) is a refractory hypotension occurring after the early neonatal period (>day 7), in very low-birthweight infants. Typically, infants stabilized within the early neonatal period develop sudden onset of circulatory collapse after the early neonatal period. The underlying pathophysiology of LCC is considered to be relative adrenal insufficiency, which is well known in Japan, but is not widely accepted in North America or Europe. The current increase in LCC in Japan suggests that the principal trigger is related to recent trends in neonatal medicine and/or newly introduced treatments for preterm infants, but the pathophysiology has not been fully elucidated. In this review, based on current knowledge regarding LCC, the pathophysiology is discussed.

Programming of the Hypothalamus-Pituitary-Adrenal Axis by Very Preterm Birth

BACKGROUND

Many very preterm (i.e., <32 weeks of gestation) newborns fail to mount an adequate adrenocortical response to stress or illness, termed relative adrenal insufficiency. Conversely, later in life these infants show features of increased glucocorticoid bioactivity, such as abdominal adiposity, insulin resistance, raised blood pressure, shorter stature and internalizing problem behavior.

SUMMARY

Studies suggested that very preterm newborns have impairments along multiple levels of the hypothalamus-pituitary-adrenal (HPA) axis. Among the impairment were defects in: (1) the pituitary responsiveness to exogenous corticotropin-releasing hormone, (2) 11β-hydroxylase activity, and (3) the interconversion between cortisol and inert cortisone. There is some evidence suggesting that later in life these infants have an increased basal secretion rate of cortisol and adrenal hyperandrogenism. However, the response to acute (psychosocial) stress was blunted rather than enhanced in them. The mechanisms explaining this switch in HPA axis activity are complex and not yet fully understood. Key Messages: Very preterm newborns have several impairments along the HPA axis that could impede an adequate adrenocortical response to stress or illness. Later in life, these infants are predisposed to increased HPA axis activity, which could partially explain their phenotype.

A review of potential pharmacogenetic effects on catecholamine responses

Considerably, variability in the clinical response to inotropic agents is observed and could be explained partially by the genetic variants, such as single-nucleotide polymorphism (SNP) in genes encoding for enzymes implicated in catecholamines synthesis, metabolism, storage and release or in the signaling pathway. This review highlights the potential effect of pharmacogenetics studies in hemodynamic response and identified 11 SNPs that could be relevant to explain the high variability drug response for a same dose. Cardiovascular instability, such as hypotension, is one of the premature birth complications. The pharmacogenetics studies evaluating these SNP may be useful to better understand the clinical outcome, particularly in this population.

Adding hydrocortisone as 1st line of inotropic treatment for hypotension in very low birth weight infants

In this pilot study the authors demonstrate the feasibility, effectiveness and safety of the combined early treatment with hydrocortisone and dopamine for refractory hypotension in preterm newborns. Very low birth weight infants born at gestational age < 30 wk or birth weight < 1250 g in the first 48 h of life with hypotension after receiving 10-20 mL/kg bolus of normal saline, were randomized to receive concurrently with the initiation of dopamine, intravenous hydrocortisone (11 infants) or an equivalent volume of placebo (11 infants). Despite no significant clinical difference between the groups including gestational age, birth weight, prevalence of chorioamnionitis, prenatal steroid treatment, cord PH, baseline cortisol level, there was a trend towards lower incidence of bronchopulmonary dysplasia (BPD), and higher survival without BPD rate in the hydrocortisone group. In this very sick small group of infants, hydrocortisone was not associated with more adverse effects, but rather showed a trend toward association with better outcome, including survival without BPD.

A comparison of combination dopamine and epinephrine treatment with high-dose dopamine alone in asphyxiated newborn piglets after resuscitation

BACKGROUND

When asphyxiated neonates require additional cardiovascular support to moderate doses of dopamine infusion, controversy exists on the differential hemodynamic effects of two approaches (adding a second inotrope vs. increasing dopamine dosage). We hypothesized that high-dose dopamine (HD) would be detrimental to systemic and regional perfusion as compared with dopamine and epinephrine (D + E) combination therapy using a swine model of neonatal hypoxia-reoxygenation (H-R).

METHODS

Twenty-seven piglets (1-4 d, 1.5-2.5 kg) were used for continuous monitoring of systemic arterial pressure (mean arterial pressure, MAP) and pulmonary arterial pressure (PAP), cardiac output (cardiac index, CI), and carotid (carotid artery flow index, CAFI), superior mesenteric (superior mesenteric artery flow index), and renal arterial flows. H-R piglets underwent 2 h of hypoxia followed by 2 h of reoxygenation before drug infusion (2 h).

RESULTS

The hemodynamics of H-R piglets deteriorated gradually after reoxygenation. HD and D + E infusions improved CI similarly (both groups vs. control; P < 0.05). Both regimens increased MAP (P < 0.05) but not PAP, with decreased PAP/MAP ratio in D + E piglets. Both regimens improved CAFI and superior mesenteric artery flow index, with decreased mesenteric vascular resistance in HD-treated piglets. No significant effect on renal perfusion was observed.

CONCLUSION

In H-R newborn piglets treated with a moderate dose of dopamine, adding epinephrine or further increasing dopamine improved systemic hemodynamics similarly; these treatments have differential effects on the pulmonary and mesenteric circulations.

Challenges in understanding the impact of blood pressure management on cerebral oxygenation in the preterm brain

Systemic hypotension in preterm infants has been related to increased mortality, cerebrovascular lesions, and neurodevelopmental morbidity. Treatment of hypotension with inotropic medications aims at preservation of end organ perfusion and oxygen delivery, especially the brain. The common inotropic medications in preterm infants include dopamine, dobutamine, adrenaline, with adjunctive use of corticosteroids in cases of refractory hypotension. Whether maintenance of mean arterial blood pressure (MAP) by use of inotropic medication is neuroprotective or not remains unclear. This review explores the different inotropic agents and their effects on perfusion and oxygenation in the preterm brain, in clinical studies as well as in animal models. Dopamine and adrenalin, because of their α-adrenergic vasoconstrictor actions, have raised concerns of reduction in cerebral blood flow (CBF). Several studies in hypotensive preterm infants have shown that dopamine elevates CBF together with increased MAP, in keeping with limited cerebro-autoregulation. Adrenaline is also effective in raising cerebral perfusion together with MAP in preterm infants. Experimental studies in immature animals show no cerebro-vasoconstrictive effects of dopamine or adrenaline, but demonstrate the consistent findings of increased cerebral perfusion and oxygenation with the use of dopamine, dobutamine, and adrenaline, alongside with raised MAP. Both clinical and animal studies report the transitory effects of adrenaline in increasing plasma lactate, and blood glucose, which might render its use as a 2nd line therapy. To investigate the cerebral effects of inotropic agents in long-term outcome in hypotensive preterm infants, carefully designed prospective research possibly including preterm infants with permissive hypotension is required. Preterm animal models would be useful in investigating the relationship between the physiological effects of inotropes and histopathology outcomes in the developing brain.

The use of an early ACTH test to identify hypoadrenalism-related hypotension in low birth weight infants

OBJECTIVE

To investigate if in preterm newborns, an early adrenocorticotropin hormone (ACTH) test can identify possible transient adrenal insufficiency (TAI), using significant hypotension as a clinical marker.

STUDY DESIGN

We studied 40 premature newborns born 24 to 29 weeks gestational age (GA) before 8 h of life. Serum cortisol levels were obtained before and 40 min after administration of 1.0 mcg kg(-1) cosyntropin. Inotropes were used to treat hypotension based on clinical assessment following no response to fluid boluses. Functional echocardiogram was used to support the clinical diagnosis of hypotension. The accuracy of the ACTH test was evaluated using receiver operating characteristic (ROC) curve.

RESULT

Study patients had mean GA of 26.6 weeks and birth weight of 876 g. In all, 30% required inotropes. The area under the ROC curve for the ACTH test was 87%. Using a cutoff of an increase in cortisol below 12% from baseline had 75% sensitivity and 93% specificity for detecting hypotension. This cutoff was associated with bronchopulmonary dysplasia (8/12 vs 7/28, 95% CI: 0.1 to 0.72), but not with other morbidities or death.

CONCLUSION

An early ACTH test using the above cutoff has high specificity for detecting hypotension, and thus, can serve as a marker for potential TAI in preterm newborns. Future studies should focus on identifying those newborns for which steroid supplementation would be most beneficial.

Inotropes in preterm infants--evidence for and against

There is significant uncertainty regarding the optimal circulatory management of preterm infants, with research in the field limited by the paucity of safe, reproducible biomarkers of circulatory function. This review discusses the physiology and pathophysiology of circulatory function in preterm infants, describes the mode of action and evidence for and against commonly used and recently trialled inotropic therapies and provides recommendations for managing circulatory dysfunction in the transitional period and in the context of sepsis/necrotizing enterocolitis. We recommend a pragmatic approach of assessing multiple aspects of circulatory function (blood pressure alone correlates weakly with volume of flow) in each infant, tailoring therapy on the basis of the change in function desired and frequently reassessing response to intervention.

Milrinone is preferred to levosimendan for mesenteric perfusion in hypoxia-reoxygenated newborn piglets treated with dopamine

INTRODUCTION

There is little information regarding the comparative hemodynamic effects of adding milrinone or levosimendan to dopamine infusion in hypoxia-reoxygenated (H-R) newborns.

RESULTS

Severely hypoxic piglets had cardiogenic shock with depressed cardiac index (CI) and mean arterial pressure (MAP). The hemodynamics deteriorated gradually after initial recovery upon reoxygenation. Heart rate and CI improved with milrinone (D+M) and levosimendan (D+L) administration (P < 0.05 vs. control). Both regimens improved carotid arterial flow and carotid vascular resistance; D+M additionally improved superior mesentric arterial flow (all P < 0.05 vs. control). No effect was found on renal arterial flow or elevated lactate state with either regimen. D+M piglets also had a lower myocardial oxidized/reduced glutathione ratio (P < 0.05 vs. control).

DISCUSSION

In conclusion, adding milrinone or levosimendan to dopamine similarly improved systemic hemodynamics in H-R newborn piglets. Milrinone also improved mesenteric perfusion and attenuated myocardial oxidative stress.

METHODS

Twenty-eight piglets (1-4 d, 1.5-2.5 kg) were instrumented for continuous monitoring of systemic MAP and pulmonary arterial pressure (PAP), CI, and carotid, superior mesenteric, and renal arterial flows. Piglets were randomized with blinding to sham-operated, H-R control (saline), and H-R dopamine (10 μg/kg/min) with D+M or D+L groups. H-R piglets underwent H-R followed by 2 h of drug infusion after reoxygenation. Tissue was collected for biochemical/oxidative stress testing and histological analysis.

Xenon offers stable haemodynamics independent of induced hypothermia after hypoxia-ischaemia in newborn pigs

PURPOSE

To assess the effect of 18 hour (h) 50% xenon (Xe) inhalation at normothermia (NT, 38.5°C) or hypothermia (HT, 33.5°C) on mean arterial blood pressure (MABP), inotropic support and heart rate (HR) following an induced perinatal global hypoxic-ischaemic insult (HI) in newborn pigs.

METHODS

Newborn pigs ventilated under inhalational anaesthesia, following a 45 min HI (inhaled oxygen fraction reduced until amplitude integrated electroencephalogram was less than 7 μV), were randomised to three Xe (n = 45) (50% Xe 18 h with NT, HT 12 h or HT 24 h) or three non-Xe groups (n = 53) (0% Xe with NT, HT 12 h or HT 24 h) under otherwise identical conditions. We measured MABP and HR every minute. Hypotension (MABP <40 mmHg) was treated sequentially with 2 × 10 mL/kg saline, dopamine, norepinephrine and hydrocortisone if required.

RESULTS

Xe maintained higher MABP during HT (5.1 mmHg, 95% CI 2.34, 7.89), rewarming (10.1 mmHg, 95% CI 6.26, 13.95) and after cessation (4.1 mmHg, 95% CI 0.37, 7.84) independent of HT, inotropic support and acidosis. Xe reduced the duration of inotropic support by 12.6 h (95% CI 5.5, 19.73). Inotropic support decreased the HR reduction induced by HT from 9 to 5 bpm/°C during cooling and from 10-7 to 4-3 bpm/°C during rewarming. There was no interaction between Xe, HT, inotropic support and acidosis. Xe during HT cleared lactate faster; 3 h post-HI median (IQR) values of (Xe HT) 2.8 mmol/L (0.9, 3.1) vs. (HT) 5.9 mmol/L (2.5, 7.9), p = 0.0004.

CONCLUSION

Xe maintained stable blood pressure, thereby reducing the inotropic support requirements during and after administration independently of induced HT-current neonatal encephalopathy treatment. Xe may offer haemodynamic benefits in clinical neuroprotection studies.

Newborns from in vitro fertilization conceived pregnancies

Infertility, defined as 'unsuccessful conception after 1 year of unprotected intercourse', is an increasing problem in many countries. Demographic data in Serbia continue to show negative trend of depopulation. One-third of married couples in Serbia are childless and half of them cannot have offspring due to health problems. Analysis of morbidity and mortality of premature newborns IVT (in vitro fertilization) conceived and treated in two Department of Intensive Care, in Novi Sad and Belgrade, Serbia during 2 years. Significant number of IVF conceived newborns are treated at NICUs. Prematurity, low birth weight, perinatal asphyxia, systemic infection, as well as proper initial stabilization, especially prevention and early treatment of systemic hypotension are important factors contributing to morbidity of these patients.

[Morbidity and mortality of premature neonates after introduction of national in vitro fertilisation programme--our experience]

INTRODUCTION

Infertility occurs in approximately 10% of couples and in vitro fertilisation (IVF) is its most efficient treatment method. The National IVF Programme started in October 1st, 2006.

OBJECTIVE

Examination of morbidity and mortality of premature neonates conceived by IVF after initiation of the National IVF Programme.

METHODS

Retrospective analysis of history charts of IVF premature neonates treated at the Neonatal Intensive Care Unit (NICU) of the Institute of Child and Youth Healthcare of Vojvodina, Novi Sad, Serbia, from March 1st, 2007 to March 1st, 2008.

RESULTS

Of 189 treated premature neonates, 25 (13.23%) were IVF conceived, with mean gestational age (GA) of 29.46 +/- 3.28 gestational weeks (GW), one-minute Apgar score 5.44 +/- 2.45, five-minute Apgar score 7.16 +/- 1.92 and birth weight (BW) 1299 +/- 484.35 g; from singleton 12 (48%), twin 10 (40%), and trigeminal 3 (12%) gestations. The largest number of neonates were of GA between 29 and 31.9 GW (12; 48%) and BW between 1500 and 2499 g (9; 36%). All of them were treated due to respiratory distress syndrome, complicated in 2 (8%) with air leak syndromes and in 4 (16%) with pulmonary haemorrhage. Congenital anomalies were detected in 2 (8%) and intracranial haemorrhage developed subsequently in 21 (84%) neonates. Lethal outcome occurred in 7 (28%) neonates, in all cases in lower gestation groups (<29 GW). Variable analysis showed significantly higher incidence of chorioamnionitis (p = 0.0004) and lower GA (p approximately 0.00), BW (p approximately 0.00), one-minute Apgar score (p = 0.0007) as well as significant difference in prophylactic surfactant application (p approximately 0.00) and mean arterial pressure on admission (p = 0.002).

CONCLUSION

Morbidity and mortality of IVF premature neonates does not differ significantly from that of other premature neonates treated at NICU. Prematurity and low BW are important factors in pathology of these neonates and final outcome is influenced by perinatal asphyxia, risk of systemic infection, prophylactic surfactant application and arterial hypotension.

Hypotension and shock in the preterm neonate

While the methods of establishing and maintaining organ perfusion differ from one clinician to the next, the underlying physiological rationale remains constant. The gestalt for correcting circulatory compromise is generally performed in a stepwise manner; first ensuring that the vasculature is filled, then administering medications to tighten the vasculature, and lastly, compensating for an immature vasculature. This stepwise approach is reflected in the pharmacological interventions of providing fluid boluses (filling the pump), giving catecholamines (tightening the pump), and starting hydrocortisone (compensating for an immature pump). While the stepwise management approach may be familiar to some nurses, it is important to understand the evidence-based rationale that supports clinical decisions. This article will outline physiology unique to the neonate, clarify terminology that surrounds hypotension and shock, and explore various methods for the treatment of circulatory compromise in the preterm neonate.

Evaluation and treatment of hypotension in the preterm infant

A large proportion of very preterm infants receive treatment for hypotension. The definition of hypotension is unclear, and, currently, there is no evidence that treating it improves outcomes or, indeed, which treatment to choose among the available alternatives. Assessment of circulatory adequacy of the preterm infant requires a careful clinical assessment and may also require ancillary investigations. The most commonly used interventions, fluid boluses and dopamine, are problematic: fluid boluses are statistically associated with worse clinical outcomes and may not even increase blood pressure, whereas dopamine increases blood pressure mostly by causing vasoconstriction and may decrease perfusion. For neither intervention is there any reliable data showing clinical benefit. Prospective trials of intervention for hypotension and circulatory compromise are urgently required.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine

BACKGROUND

The Institute of Medicine calls for the use of clinical guidelines and practice parameters to promote "best practices" and to improve patient outcomes.

OBJECTIVE

2007 update of the 2002 American College of Critical Care Medicine Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock.

PARTICIPANTS

Society of Critical Care Medicine members with special interest in neonatal and pediatric septic shock were identified from general solicitation at the Society of Critical Care Medicine Educational and Scientific Symposia (2001-2006).

METHODS

The Pubmed/MEDLINE literature database (1966-2006) was searched using the keywords and phrases: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation (ECMO), and American College of Critical Care Medicine guidelines. Best practice centers that reported best outcomes were identified and their practices examined as models of care. Using a modified Delphi method, 30 experts graded new literature. Over 30 additional experts then reviewed the updated recommendations. The document was subsequently modified until there was greater than 90% expert consensus.

RESULTS

The 2002 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and AHA sanctioned recommendations. Centers that implemented the 2002 guidelines reported best practice outcomes (hospital mortality 1%-3% in previously healthy, and 7%-10% in chronically ill children). Early use of 2002 guidelines was associated with improved outcome in the community hospital emergency department (number needed to treat = 3.3) and tertiary pediatric intensive care setting (number needed to treat = 3.6); every hour that went by without guideline adherence was associated with a 1.4-fold increased mortality risk. The updated 2007 guidelines continue to recognize an increased likelihood that children with septic shock, compared with adults, require 1) proportionally larger quantities of fluid, 2) inotrope and vasodilator therapies, 3) hydrocortisone for absolute adrenal insufficiency, and 4) ECMO for refractory shock. The major new recommendation in the 2007 update is earlier use of inotrope support through peripheral access until central access is attained.

CONCLUSION

The 2007 update continues to emphasize early use of age-specific therapies to attain time-sensitive goals, specifically recommending 1) first hour fluid resuscitation and inotrope therapy directed to goals of threshold heart rates, normal blood pressure, and capillary refill 70% and cardiac index 3.3-6.0 L/min/m.

Predictive factors for survival for out-born infants born between 23 and 24 weeks of gestation in the post-surfactant era: fourteen years' experience in a single neonatal care unit, 1987-2000

BACKGROUND

The purpose of the present paper was to identify the predictive factors for survival for out-born infants born between 23 and 24 weeks of gestation.

METHODS

Ninety-two infants born between 23 and 24 weeks' gestation who were admitted to a level III neonatal intensive care unit from 1987 to 2000, were retrospectively studied. Survival was defined as discharge from the neonatal intensive care unit. Logistic regression was done to determine which clinical factors were most predictive of survival. The independent variables that were entered into the models were determined by preliminary univariate analysis.

RESULTS

Ninety-two infants were enrolled in the present study, 49 of whom survived in the surfactant era. The four variables that were found to be most predictive for survival on logistic regression were systolic blood pressure at 6 h (odds ratio [OR], 1.3; 95% confidence interval [CI]: 1.11-1.44 1 mmHg), ventilatory index < 0.047 (OR, 4.8; 95%CI: 1.07-21.65), initial hemoglobin value (OR, 1.6; 95%CI: 1.09-2.34/1 g/dL), and base excess at 6 h (OR, 2.1; 95%CI: 1.08-1.84/5 mEq/L).

CONCLUSIONS

A total of 53.2% of infants delivered between 23 and 24 weeks of gestation survived at discharge after introduction of surfactant replacement therapy. Early cardiopulmonary adaptation and initial hemoglobin value are key factors for survival in infants born at 23-24 weeks of gestation.

Umbilical cord milking reduces the need for red cell transfusions and improves neonatal adaptation in infants born at less than 29 weeks' gestation: a randomised controlled trial

OBJECTIVE

To investigate the effects of umbilical cord milking on the need for red blood cell (RBC) transfusion and morbidity in very preterm infants.

PATIENTS AND METHODS

40 singleton infants born between 24 and 28 weeks' gestation were randomly assigned to receive umbilical cord clamped either immediately (control group, n = 20) or after umbilical cord milking (milked group, n = 20). Primary outcome measures were the probability of not needing transfusion, determined by Kaplan-Meier analysis, and the total number of RBC transfusions. Secondary outcome variables were haemoglobin value and blood pressure at admission.

RESULTS

There were no significant differences in gestational age and birth weight between the two groups. The milked group was more likely not to have needed red cell transfusion (p = 0.02) and had a decreased number (mean (SD)) of RBC transfusions (milked group 1.7 (3.0) vs controls 4.0 (4.2); p = 0.02). The initial mean (SD) haemoglobin value was higher in the milked group (165 (14) g/l) than in the controls (141 (16) g/l); p<0.01). Mean (SD) blood pressure at admission was significantly higher in the milked group (34 (9) mm Hg) than in the controls 28 (8) mm Hg; p = 0.03). There was no significant difference in mortality between the groups. The milked group had a shorter duration of ventilation or supplemental oxygen than the control group.

CONCLUSION

Milking the umbilical cord is a safe procedure, reducing the need for RBC transfusions, and the need for circulatory and respiratory support in very preterm infants.

Relationship between blood pressure and blood flow in newborn preterm infants

BACKGROUND

Arterial blood pressure remains the most frequently monitored indicator of neonatal circulatory status. However, studies of systemic perfusion in neonates have often shown only weakly positive associations with blood pressure.

OBJECTIVES

To examine the relationship between invasively monitored arterial blood pressure and four measurements of systemic perfusion: left and right ventricular outputs, superior vena caval (SVC) flow and descending aortic (DAo) flow.

DESIGN

Echocardiographic assessments of perfusion were performed four times in the first 48 h of postnatal life in a cohort of 34 preterm (<30 weeks) infants. Arterial blood pressure was monitored invasively over the exact duration of the echocardiogram.

RESULTS

In the first 48 h of postnatal life there was no evidence of a positive association between blood pressure and volume of blood flow in any of the four vessels studied. At 5 h postnatal age there was a weak but significant inverse correlation between volume of SVC flow and arterial blood pressure (p = 0.04). A similar but non-significant trend was seen at 12 h postnatal age.

CONCLUSIONS

Infants with reduced systemic perfusion tend to have normal or high blood pressure in the first hours of life, suggesting that a high systemic vascular resistance may lead to reduced blood flow. Low blood pressure does not correlate with poor perfusion in the first 48 h of postnatal life in sick preterm infants.

Diagnostic criteria and therapeutic interventions for the hypotensive very low birth weight infant

INTRODUCTION

The diagnosis and management of hypotension in the very low birth weight (VLBW) is a controversial area.

OBJECTIVE

To establish if there is any consensus in the diagnostic criteria and therapeutic interventions in the hypotensive VLBW among neonatologists in Canada.

METHODS

A postal questionnaire was sent to neonatologists in all level II and III neonatal intensive care units throughout Canada.

RESULTS

In total, 120 questionnaires were sent. Ninety-five completed questionnaires were returned. Seventy-six percent of respondents work in units where at least 50 VLBWs and 43% where at least 100 VLBWs are cared for annually. Fifty-seven percent of the respondents have at least 10 years experience as practicing neonatologists. 25.8% rely on blood pressure values alone when intervening, the most common being a blood pressure less than gestational age in weeks. Ninety-seven percent of respondents commence therapy with a fluid bolus. Normal saline is the predominant volume administered (95%). Dopamine remains the pressor of choice. Great variation exists in starting doses and total amount administered. Similar variation exists with epinephrine, with tenfold differences in starting doses (0.01-0.1 mcg/kg/min) and tenfold differences in maximum dose (0.4-4 mc/kg/min) administered. Steroid doses used ranged from 0.1 mg/kg/dose of hydrocortisone to 5 mg/kg/dose. Bicarbonate is rarely used. Three predominant therapeutic regimes exist. These include (i) volume followed by dopamine then a steroid (32%), (ii) volume, dopamine, dobutamine (29%), (iii) volume, dopamine, epinephrine (22%).

CONCLUSION

This is the first large study of practices among neonatologists addressing hypotension in the VLBW infant. There is wide variation in practice, which is a reflection of the lack of good evidence currently available for this very common problem.

Chorioamnionitis with or without funisitis increases the risk of hypotension in very low birthweight infants on the first postnatal day but not later

OBJECTIVE

To evaluate the relation between chorioamnionitis and hypotension in very low birthweight infants.

METHODS

Retrospective cohort study in infants with a birth weight of <1500 g born between January 2002 and September 2004. The placentas were examined for evidence of chorioamnionitis and funisitis. Hypotension was defined by the use of vasopressors.

RESULTS

Of 105 infants, 37 (35%) were chorioamnionitis positive. The onset of hypotension had a skewed distribution: day 1 for 30 episodes and scattered from day 2 to day 19 for the remaining 22. Of the 30 infants who developed hypotension on day 1, 17 (57%) were chorioamnionitis positive. The mean maturity of the chorioamnionitis positive group was 27.91 weeks, marginally less than the mean maturity of 29.05 weeks of the chorioamnionitis negative group (p = 0.05). After adjustment of the effects for confounding variables (birth weight, gestation, surfactant therapy, mechanical ventilation on day 1, high frequency oscillatory ventilation, patent ductus arteriosus), chorioamnionitis was the significant factor in line with hypotension developing on day 1 (adjusted odds ratio 5.14, 95% confidence interval 1.51 to 17.50). There was no evidence that hypotension developing after day 1 was associated with chorioamnionitis.

CONCLUSIONS

There is a strong association between chorioamnionitis and hypotension developing on day 1 in very low birthweight infants.

Dexamethasone selectively inhibits differentiation of cord blood stem cell derived-dendritic cell (DC) precursors into immature DCs

Perinatal dexamethasone (Dx) alters the immune system leading to increased infections and developmental abnormalities. Dendritic cells (DCs) derived from cord-blood monocytes are especially Dx sensitive and we sought to determine the effects of Dx on cord-blood CD34+-DCs. Distinct stages of cord-blood CD34+-DC development were delineated: pre-DC, immature, and mature DCs. Dx added during development of pre-DCs did not suppress precursor number, or translocate the glucocorticoid receptor (GcR) from the cytoplasm to the nucleus. However, Dx added during pre-DCs differentiation into immature DCs, prompted GcR translocation to the nucleus, enhanced DC apoptosis, suppressed differentiation to CD1a+ cells, inhibited expression of CD86, reduced subsequent CD83 expression, maintained DC endocytic activity, suppressed IL-6 secretion, enhanced IL-10 secretion, and reduced DC-mediated T cell stimulation. Dx added during the maturation stage caused less dramatic effects. Thus, Dx stalled maturation, selectively induced apoptosis of developing DCs and the sensitivity peaked during pre-DCs differentiation into immature DCs.