Milrinone use for hemodynamic instability in patent ductus arteriosus ligation

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.

Reassessing the role of milrinone in the treatment of heart failure and pulmonary hypertension in neonates and children: a systematic review and meta-analysis

To evaluate milrinone's impact on pediatric cardiac function, focusing on its specific role as an inotrope and lusitrope, while considering its systemic and pulmonary vasodilatory effects. Search of PubMed, EMBASE, and the Cochrane Library up to August 2023. We included all studies that evaluated milrinone in children under 18 years old in neonatal, pediatric, or cardiac intensive care units. We excluded case reports, studies that did not provide tabular information on milrinone's outcomes, and studies focused on non-intensive care populations. We extracted data on the research design, objectives, study sample, and results of each study, including the impact of milrinone and any associated factors. We screened a total of 9423 abstracts and 41 studies were ultimately included. Milrinone significantly improved left ventricular ejection fraction (WMD 3.41 [95% CI 0.61 - 6.21]), left ventricle shortening fraction (WMD 4.25 [95% CI 3.43 - 5.08]), cardiac index (WMD 0.50 [95% CI 0.32 to 0.68]), left ventricle output (WMD 55.81 [95% CI 4.91 to 106.72]), serum lactate (WMD -0.59 [95% CI -1.15 to -0.02]), and stroke volume index (WMD 2.95 [95% CI 0.09 - 5.82]). However, milrinone was not associated with improvements in ventricular myocardial performance index (WMD -0.01 [95% CI -0.06 to 0.04]) and ventricular longitudinal strain (WMD -2.14 [95% CI -4.56 to 0.28]). Furthermore, milrinone was not associated with isovolumetric relaxation time reduction (WMD -8.87 [95% CI -21.40 to 3.66]).

CONCLUSION

Our meta-analysis suggests potential clinical benefits of milrinone by improving cardiac function, likely driven by its systemic vasodilatory effects. However, questions arise about its inotropic influence and the presence of a lusitropic effect. Moreover, milrinone's pulmonary vasodilatory effect appears relatively weaker compared to its systemic actions. Further research is needed to elucidate milrinone's precise mechanisms and refine its clinical applications in pediatric practice.

WHAT IS KNOWN

• Milrinone is a phosphodiesterase III inhibitor that has been used to treat a variety of pediatric and neonatal conditions. • Milrinone is believed to exert its therapeutic effects by enhancing cardiac contractility and promoting vascular relaxation.

WHAT IS NEW

• Milrinone may not have a significant inotropic effect. • Milrinone's pulmonary vasodilatory effect is less robust than its systemic vasodilatory effect.

Phenotyping respiratory decompensation following definitive closure of the patent ductus arteriosus in preterm infants

OBJECTIVE

To identify risk factors associated with high-frequency ventilation (HFV) following definitive closure of the patent ductus arteriosus (PDA).

METHODS

We performed a retrospective study of premature infants (<37 weeks) who were mechanically ventilated before and after surgical or transcatheter PDA closure. Primary outcome was HFV requirement within 24 h of procedure. Logistic regression was used to estimate clinical associations with post procedure HFV requirement.

RESULTS

We identified 110 infants who were mechanically ventilated before PDA closure, of which 48 (44%) escalated to HFV within 24 h after closure. In the multivariable model, surgical ligation (OR 21.5, 95% CI 1.6-284), elevated Respiratory Severity Score (RSS) 1 h post-procedure (OR 1.78, 95% CI 1.07-2.99) and 12 h post-procedure (OR 2.12, 95% CI 1.37-3.26) were independent predictors of HFV.

CONCLUSION

Surgical ligation and elevated RSS values over the first 12 h after PDA closure are risk factors for HFV.

Which Inotropic Drug, Dobutamine or Milrinone, Is Clinically More Effective in the Treatment of Postligation Cardiac Syndrome in Preterm Infants?

OBJECTIVE

This study aimed to detect which of the two main medicines suggested in the treatment of postligation cardiac syndrome (PLCS)-dobutamine or mirinone-possesses a more therapeutic effect. While doing this, clinicians are provided with a broader perspective on the treatment and follow-up of cases. The desire was to increase the treatability and monitor ability of the cases in question and hence their survivability.

STUDY DESIGN

A retrospective review of a cohort of infants with PLCS was conducted between March 2012 and December 2018. In the treatment of infants with PLCS, dobutamine (dobutamine study group-DSG) or milrinone (milrinone study group-MSG) was used. The respiration, cardiac, echocardiography, and perfusion parameters of the cases were assessed both before and after ligation. Based on the data obtained, both the effects of the medicines on PLCS and the difference between their therapeutic effects were studied. The accuracy of prognostication was assessed with receiver operating characteristic analyses.

RESULTS

PLCS was detected in 29 (34.1%) of 85 patent ductus arteriosus ligation cases in total. Of all the PLCS cases, 13 (44.8%) were treated with dobutamine and 16 (55.2%) with milrinone. It was observed that the effects of the medicines on the respiratory system and cardiovascular system manifested in the third and 6th hour, respectively. It was detected that both medicines had more effect on the systolic blood pressure (SBP) (area under the curve [AUC]: 0.997/0.996, p = 0.001/0.002) than on the diastolic blood pressure (AUC: 0.911/0.843, p = 0.032/0.046).

CONCLUSION

Dobutamine and milrinone, two primary medicines that can be used in the treatment of cases with PLCS, possess similar therapeutic effects on this pathology. In addition, their postoperative therapeutic effects on the SBP are more in the foreground.

Near-infrared spectroscopy for perioperative assessment and neonatal interventions

Perioperative applications of near-infrared spectroscopy (NIRS) to monitor regional tissue oxygenation and perfusion in cardiac and noncardiac surgery are of increasing interest in neonatal care. Complex neonatal surgery can impair adequate oxygen delivery and tissue oxygen consumption and increase the risk of neurodevelopmental delay. Coupled with conventional techniques, NIRS monitoring may enable targeted hemodynamic management of the circulation in both cardiac and noncardiac surgical procedures. In this narrative review, we discuss the application of perioperative NIRS in specific neonatal interventions, including surgical intervention for congenital heart defects, definitive closure of the patent ductus arteriosus, neurological and gastrointestinal disorders, and use of extracorporeal membrane oxygenation. We identified areas for future research within disease-specific indications and offer a roadmap to aid in developing evidence-based targeted diagnostic and management strategies in neonates. IMPACT: There is growing recognition that perioperative NIRS monitoring, used in conjunction with conventional monitoring, may provide critical hemodynamic information that either complements clinical impressions or delivers novel physiologic insight into the neonatal circulatory and perfusion pathways.

Risk factors associated with prolonged mechanical ventilation after surgical patent ductus arteriosus ligation in preterm infants

BACKGROUND

One of the main pathophysiologies of a hemodynamically significant patent ductus arteriosus (hsPDA) involves pulmonary over-circulation. However, PDA treatment does not present with uniform effects on pulmonary outcomes. We aimed to evaluate the clinical characteristics - in particular, respiratory parameters - associated with prolonged mechanical ventilation after PDA ligation.

METHODS

Preterm infants ≤32 weeks gestation were included in the study. Infants who underwent PDA ligation were grouped depending on whether the infant successfully was extubated ≤14 d after ligation or required prolonged invasive mechanical ventilation >14 d after ligation. The clinical characteristics, including the parameters concerning the respiratory illness severity and hemodynamical significance of PDA shunt, were compared between the two groups.

RESULTS

Among 172 preterm infants, 36 (20.9%) infants underwent surgical PDA ligation. Fifteen (41.6%) infants were successfully extubated at ≤14 d after ligation, and 21 (58.3%) infants required prolonged invasive mechanical ventilation for >14 d after ligation. In the univariable analysis, the infants who required prolonged mechanical ventilation was significantly smaller in terms of gestational age (GA) and birth weight and tended to present a greater respiratory illness severity [represented by the use of high-frequency oscillatory ventilation (HFOV) and greater RSS (respiratory severity score)/kg] with a larger PDA size prior to PDA ligation. In the multivariable logistic regression analysis, peak preoperative RSS/kg (p = 0.012, OR = 0.207, 95% CI = 0.060-0.706) was the only significant factor associated with prolonged mechanical ventilation after PDA ligation.

CONCLUSION

Preterm infants with the compromised respiratory condition may be prone to prolonged mechanical ventilation after PDA ligation. The respiratory status during the early phase of life should be considered when evaluating the effect of PDA treatment. With an extended view, distinguishing infants with such risk factors may lead to more polished treatment strategies toward hsPDA.

Management of Neonatal Hypotension and Shock

The current standard approach to manage circulatory insufficiency is inappropriately simple and clear: respond to low blood pressure to achieve higher values. However, the evidence for this is limited affecting all steps within the process: assessment, decision making, therapeutic options, and treatment effects. We have to overcome the 'one size fits all' approach and respect the dynamic physiologic transition from fetal to neonatal life in the context of complex underlying conditions. Caregivers need to individualize their approaches to individual circumstances. This paper will review various clinical scenarios, including managing transitional low blood pressure, to circulatory impairment involving different pathologies such as hypoxia-ischemia and sepsis. We will highlight the current evidence and set potential goals for future development in these areas. We hope to encourage caregivers to question the current standards and to support urgently needed research in this overlooked but crucial field of neonatal intensive care.

Population Pharmacokinetics and Dosing of Milrinone After Patent Ductus Arteriosus Ligation in Preterm Infants

OBJECTIVES

The postoperative course of patent ductus arteriosus ligation is often complicated by postligation cardiac syndrome, occurring in 10-45% of operated infants. Milrinone might prevent profound hemodynamic instability and improve the recovery of cardiac function in this setting. The present study aimed to describe the population pharmacokinetics of milrinone in premature neonates at risk of postligation cardiac syndrome and give dosing recommendations.

DESIGN

A prospective single group open-label pharmacokinetics study.

SETTINGS

Two tertiary care neonatal ICUs: Tallinn Children's Hospital and Tartu University Hospital, Estonia.

PATIENTS

Ten neonates with postmenstrual age of 24.6-30.1 weeks and postnatal age of 5-27 days undergoing patent ductus arteriosus ligation and at risk of postligation cardiac syndrome, based on echocardiographic assessment of left ventricular output of less than 200 mL/kg/min 1 hour after the surgery.

INTERVENTIONS

Milrinone at a dose of 0.73 μg/kg/min for 3 hours followed by 0.16 μg/kg/min for 21 hours. Four blood samples from each patient for milrinone plasma concentration measurements were collected.

MEASUREMENTS AND MAIN RESULTS

Concentration-time data of milrinone were analyzed with nonlinear mixed-effects modeling software (NONMEM Version 7.3 [ICON Development Solutions, Ellicott City, MD]). Probability of target attainment simulations gave a dosing schedule that maximally attains concentration targets of 150-250 μg/L. Milrinone pharmacokinetics was described by a one-compartmental linear model with allometric scaling to bodyweight and an age maturation function of glomerular filtration rate. Parameter estimates for a patient with the median weight were 0.350 (L/hr) for clearance and 0.329 (L) for volume of distribution. The best probability of target attainment was achieved with a loading dose of 0.50 μg/kg/min for 3 hours followed by 0.15 μg/kg/min (postmenstrual age < 27 wk) or 0.20 μg/kg/min (postmenstrual age ≥ 27 wk).

CONCLUSIONS

Population pharmacokinetic modeling and simulations suggest a slow loading dose followed by maintenance infusion to reach therapeutic milrinone plasma concentrations within the timeframe of the postligation cardiac syndrome.

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.