Pediatric cardiovascular drug dosing in critically ill children and extracorporeal membrane oxygenation

Next-generation pediatric care: nanotechnology-based and AI-driven solutions for cardiovascular, respiratory, and gastrointestinal disorders

BACKGROUND

Global pediatric healthcare reveals significant morbidity and mortality rates linked to respiratory, cardiac, and gastrointestinal disorders in children and newborns, mostly due to the complexity of therapeutic management in pediatrics and neonatology, owing to the lack of suitable dosage forms for these patients, often rendering them "therapeutic orphans". The development and application of pediatric drug formulations encounter numerous challenges, including physiological heterogeneity within age groups, limited profitability for the pharmaceutical industry, and ethical and clinical constraints. Many drugs are used unlicensed or off-label, posing a high risk of toxicity and reduced efficacy. Despite these circumstances, some regulatory changes are being performed, thus thrusting research innovation in this field.

DATA SOURCES

Up-to-date peer-reviewed journal articles, books, government and institutional reports, data repositories and databases were used as main data sources.

RESULTS

Among the main strategies proposed to address the current pediatric care situation, nanotechnology is specially promising for pediatric respiratory diseases since they offer a non-invasive, versatile, tunable, site-specific drug release. Tissue engineering is in the spotlight as strategy to address pediatric cardiac diseases, together with theragnostic systems. The integration of nanotechnology and theragnostic stands poised to refine and propel nanomedicine approaches, ushering in an era of innovative and personalized drug delivery for pediatric patients. Finally, the intersection of drug repurposing and artificial intelligence tools in pediatric healthcare holds great potential. This promises not only to enhance efficiency in drug development in general, but also in the pediatric field, hopefully boosting clinical trials for this population.

CONCLUSIONS

Despite the long road ahead, the deepening of nanotechnology, the evolution of tissue engineering, and the combination of traditional techniques with artificial intelligence are the most recently reported strategies in the specific field of pediatric therapeutics.

Priorities for Clinical Research in Pediatric Extracorporeal Membrane Oxygenation Anticoagulation From the Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To identify and prioritize research questions for anticoagulation and hemostasis management of neonates and children supported with extracorporeal membrane oxygenation (ECMO) from the Pediatric ECMO Anticoagulation CollaborativE (PEACE) consensus.

DATA SOURCES

Systematic review was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021, followed by serial consensus conferences of international, interprofessional experts in the management of ECMO for critically ill neonates and children.

STUDY SELECTION

The management of ECMO anticoagulation for critically ill neonates and children.

DATA EXTRACTION

Within each of the eight subgroups, two authors reviewed all citations independently, with a third independent reviewer resolving any conflicts.

DATA SYNTHESIS

Following the systematic review of MEDLINE, EMBASE, and Cochrane Library databases from January 1988 to May 2021, and the consensus process for clinical recommendations and consensus statements, PEACE panel experts constructed research priorities using the Child Health and Nutrition Research Initiative methodology. Twenty research topics were prioritized, falling within five domains (definitions and outcomes, therapeutics, anticoagulant monitoring, protocolized management, and impact of the ECMO circuit and its components on hemostasis).

CONCLUSIONS

We present the research priorities identified by the PEACE expert panel after a systematic review of existing evidence informing clinical care of neonates and children managed with ECMO. More research is required within the five identified domains to ultimately inform and improve the care of this vulnerable population.

Reducing hydrophobic drug adsorption in an in-vitro extracorporeal membrane oxygenation model

Extracorporeal membrane oxygenation (ECMO) is a life-saving cardiopulmonary bypass technology for critically ill patients with heart and lung failure. Patients treated with ECMO receive a range of drugs that are used to treat underlying diseases and critical illnesses. However, the dosing guidelines for these drugs used in ECMO patients are unclear. Mortality rate for patients on ECMO exceeds 40% partly due to inaccurate dosing information, caused in part by the adsorption of drugs in the ECMO circuit and its components. These drugs range in hydrophobicity, electrostatic interactions, and pharmacokinetics. Propofol is commonly administered to ECMO patients and is known to have high adsorption rates to the circuit components due to its hydrophobicity. To reduce adsorption onto the circuit components, we used micellar block copolymers (Poloxamer 188TM and Poloxamer 407TM) and liposomes tethered with poly(ethylene glycol) to encapsulate propofol, provide a hydrophilic shell and prevent its adsorption. Size, polydispersity index (PDI), and zeta potential of the delivery systems were characterized by dynamic light scattering, and encapsulation efficiency was characterized using High Performance Liquid Chromatography (HPLC). All delivery systems used demonstrated colloidal stability at physiological conditions for seven days, cytocompatibility with a human leukemia monocytic cell line, i.e., THP-1 cells, and did not activate the complement pathway in human plasma. We demonstrated a significant reduction in adsorption of propofol in an in-vitro ECMO model upon encapsulation in micelles and liposomes. These results show promise in reducing the adsorption of hydrophobic drugs to the ECMO circuits by encapsulation in nanoscale structures tethered with hydrophilic polymers on the surface.

Direct and continuous dosing of propofol can saturate Ex vivo ECMO circuit to improve propofol recovery

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary bypass device that provides life-saving complete respiratory and cardiac support in patients with cardiorespiratory failure. The majority of drugs prescribed to patients on ECMO lack a dosing strategy optimized for ECMO patients. Several studies demonstrated that dosing is different in this population because the ECMO circuit components can adsorb drugs and affect drug exposure substantially. Saturation of ECMO circuit components by drug disposition has been posited but has not been proven. In this study, we have attempted to determine if propofol adsorption is saturable in ex vivo ECMO circuits.

METHODS

We injected ex vivo ECMO circuits with propofol, a drug that is highly adsorbed to the ECMO circuit components. Propofol was injected as a bolus dose (50 μg/mL) and a continuous infusion dose (6 mg/h) to investigate the saturation of the ECMO circuit.

RESULTS

After the bolus dose, only 27% of propofol was recovered after 30 minutes which is as expected. However, >80% propofol was recovered after the infusion dose which persisted even when the infusion dose was discontinued.

CONCLUSION

Our results suggest that if ECMO circuits are dosed directly with propofol, drug adsorption can be eliminated as a cause for altered drug exposure. Field of Research: Artificial Lung/ECMO.

Micellar Encapsulation of Propofol Reduces its Adsorption on Extracorporeal Membrane Oxygenator (ECMO) Circuit

Extracorporeal membrane oxygenation (ECMO) is a life-saving cardiopulmonary bypass device used on critically ill patients with refractory heart and lung failure. Patients supported with ECMO receive numerous drugs to treat critical illnesses and the underlying diseases. Unfortunately, most drugs prescribed to patients on ECMO lack accurate dosing information. Dosing can be variable in this patient population because the ECMO circuit components can adsorb drugs and affect drug exposure substantially. Propofol is a widely used anesthetic in ECMO patients and is known to have high adsorption rates in ECMO circuits due to its high hydrophobicity. In an attempt to reduce adsorption, we encapsulated propofol with Poloxamer 407 (Polyethylene-Polypropylene Glycol). Size and polydispersity index (PDI) were characterized using dynamic light scattering. Encapsulation efficiency was analyzed using High performance liquid chromatography. Cytocompatibility of micelles was analyzed against human macrophages and the formulation was finally injected in an ex-vivo ECMO circuit to determine the adsorption of propofol. Size and PDI of micellar propofol were 25.5 ± 0.8 nm and 0.08 ± 0.01, respectively. Encapsulation efficiency of the drug was 96.1 ± 1.3%. Micellar propofol demonstrated colloidal stability at physiological temperature for a period of 7 days, and was cytocompatible with human macrophages. Micellar propofol demonstrated a significant reduction in adsorption of propofol in the ECMO circuit at earlier time points compared to free propofol (Diprivan®). We observed 97 ± 2% recovery of the propofol from the micellar formulation after an infusion. These results demonstrate the potential of micellar propofol to reduce drug adsorption to ECMO circuit.

Impact of Clinical Pharmacist-Led Interventions on Drug-Related Problems Among Pediatric Cardiology Patients: First Palestinian Experience

Background

Discovery and resolution of drug-related problems (DRPs) are taken as the cornerstone in the entire pharmaceutical care process to improve patient outcomes. Very limited reports on the analysis of DRPs in pediatric cardiology have been released worldwide.

Objective

The aim of this study was to disclose the impact of clinical pharmacist’s interventions on DRPs among pediatric cardiology patients in Palestine.

Methods

Between January and September 2021, a prospective interventional study involving clinical pharmacist’s care was implemented in the cardiology ward of Al-Rantisy Specialized Pediatric Hospital in Gaza, Palestine. Pharmaceutical Care Network Europe model 9.1 was used to identify DRPs, causes of the problem, clinical pharmacist’s interventions, cardiologist’s acceptance, and outcomes.

Results

A total of 309 DRPs were identified in 87 patients, representing a mean of 3.55 problems per patient. The most common DRPs were “Treatment effectiveness” (50.8%) and “Treatment safety” (30.4%), while the main causes of these DRPs were “Errors in dose timing instructions” (9.4%) and “Inappropriate combination of drugs” (13.7%), respectively. Analysis revealed that 96.7% of the interventions suggested by the clinical pharmacist were accepted by cardiologists and that 92.1% of problems were fully resolved with improved patient outcomes.

Conclusion

Interventions offered by the clinical pharmacist successfully addressed DRPs and positively impacted treatment outcomes in pediatric cardiology patients. With the high acceptance of pediatric cardiologists to the clinical pharmacist’s experience in Palestine, there is a growing need to integrate clinical pharmacists into cardiology teamwork care to optimize drug therapy and patient safety.

Amiodarone Extraction by the Extracorporeal Membrane Oxygenation Circuit

Amiodarone is an anti-arrhythmic agent that is frequently used to treat tachycardias in critically ill adults and children. Because of physicochemical properties of amiodarone, extracorporeal membrane oxygenation (ECMO) circuits are expected to extract amiodarone from circulation, increasing the risk of therapeutic failure. The present study seeks to determine amiodarone extraction by the ECMO circuit. Amiodarone was administered to three ex vivo circuit configurations (n = 3 per configuration) to determine the effect of each circuit component on drug extraction. The circuits were primed with human blood; standard amiodarone doses were administered; and serial samples were collected over 24 hours. Additional circuits were primed with crystalloid fluid to analyze the effect of blood on extraction and to investigate circuit saturation by drug. The crystalloid circuits were dosed multiple times over 72 hours, including a massive dose at 48 hours. For both setups, the flow was set to 1 L/min. Drug was added to separate tubes containing the prime solution to serve as controls. Drug concentrations were quantified with a validated assay, and drug recovery was calculated for each sample. Mean recovery for the circuits and controls were compared to correct for drug degradation over time. Amiodarone was heavily extracted by all ECMO circuit configurations. Eight hours after dosing, mean recovery in the blood prime circuits was 13.5-22.1%. In the crystalloid prime circuits, drug recovery decreased even more rapidly, with a mean recovery of 22.0% at 30 minutes. Similarly, drug recovery decreased more quickly in the crystalloid prime controls than in the blood prime controls. Saturation was not achieved in the crystalloid prime circuits, as final amiodarone concentrations were at the lower limit of quantification. The results suggest that amiodarone is rapidly extracted by the ECMO circuit and that saturation is not achieved by standard doses. In vivo circuit extraction may cause decreased drug exposure.

Pharmacotherapy in Critically Ill Children: A Retrospective Review of 17,199 Admissions

OBJECTIVES

Despite the ubiquitous role of pharmacotherapy in the care of critically ill children, descriptions of the extent of pharmacotherapy in critical illness are limited. Greater understanding of drug therapy can help identify clinically important associations and assist in the prioritization of efforts to address knowledge gaps. The objectives of this study were to describe the diversity, volume, and patterns of pharmacotherapy in critically ill children.

DESIGN

A retrospective cohort study was performed with patient admissions to the ICU between July 31, 2006, and July 31, 2015.

SETTING

The study took place at a single, free-standing, pediatric, quaternary center.

PATIENTS

Eligible patient admissions were admitted to the ICU for more than 6 hours and received one or more drug administration. There were a total 17,482 patient-admissions and after exclusion of 283 admissions (2%) with no documented enteral or parenteral drug administration, 17,199 eligible admissions were studied.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 17,199 eligible admissions were admitted to the ICU for 2,208,475 hours and received 515 different drugs. The 1,954,171 administrations were 894,709 (45%) enteral administrations, 998,490 (51%) IV injections and 60,972 (3%) infusions. Infusions were administered for 4,476,538 hours. Twelve-thousand two-hundred seventy-three patients (71%) were administered five or more different drugs on 80,943 of patient days (75%). The 10 most commonly administered drugs comprised of 834,441 administrations (43%).

CONCLUSIONS

Drug administration in the ICU is complex, involves many medications, and the potential for drug interaction and reaction is compounded by the volume and diversity of therapies routinely provided in ICU. Further evaluation of polytherapy could be used to improve outcomes and enhance the safety of pharmacotherapy in critically ill children.

Intravenous Sotalol for the Treatment of Ventricular Dysrhythmias in an Infant on Extracorporeal Membrane Oxygenation

Sotalol is a class III anti-arrhythmic agent with beta receptor blocking properties. Intravenous (IV) sotalol may be useful to treat refractory atrial and ventricular arrhythmias. A report on the efficacy and safety of IV sotalol in an infant on extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT), who developed refractory ventricular arrhythmias following surgery for congenital heart disease. A 10-day old infant with severe pulmonary valve stenosis underwent surgical pulmonary valvectomy and enlargement of the main pulmonary artery. Post-operatively, the patient developed hemodynamically significant accelerated idioventricular rhythm which was not responsive to a combination of amiodarone, lidocaine, and procainamide leading to 2 cardiac arrest events and placement on ECMO. The amiodarone infusion was uptitrated to 20 mcg/kg/min, but episodes of the hemodynamically compromising arrhythmia continued. Amiodarone was discontinued and IV sotalol was initiated at 42 mg/m²/day, divided to 3 doses, and administered every 8 h, which completely suppressed the arrhythmia. The initial sotalol dose was calculated based on a daily dose of 90 mg/m² and reduced by an age-related factor as recommended by the FDA approved prescribing information. Subsequently, acute kidney injury requiring CRRT developed. The patient remained on IV sotalol for 3 weeks and then transitioned to oral sotalol. The oral dose was increased to 44 mg/m²/day (3.5 mg every 8 h) to account for the difference in bioavailability between the IV and oral formulations. Serial sotalol levels during IV and PO therapy remained therapeutic on ECMO and CRRT. The patient maintained normal sinus rhythm on sotalol without adverse events. IV sotalol in the setting of ECMO and CRRT was safe and effective in controlling refractory hemodynamically compromising accelerated idioventricular rhythm unresponsive to amiodarone.

Population Pharmacokinetics of Intramuscular and Intravenous Ketamine in Children

Ketamine is an N-methyl D-aspartate receptor antagonist used off-label to facilitate dissociative anesthesia in children undergoing invasive procedures. Available for both intravenous and intramuscular administration, ketamine is commonly used when vascular access is limited. Pharmacokinetic (PK) data in children are sparse, and the bioavailability of intramuscular ketamine in children is unknown. We performed 2 prospective PK studies of ketamine in children receiving either intramuscular or intravenous ketamine and combined the data to develop a pediatric population PK model using nonlinear mixed-effects methods. We applied our model by performing dosing simulations targeting plasma concentrations previously associated with analgesia (>100 ng/mL) and anesthesia awakening (750 ng/mL). A total of 113 children (50 intramuscular and 63 intravenous ketamine) with a median age of 3.3 years (range 0.02 to 17.6 years), and median weight of 14 kg (2.4 to 176.1) contributed 275 plasma samples (149 after intramuscular, 126 after intravenous ketamine). A 2-compartment model with first-order absorption following intramuscular administration and first-order elimination described the data best. Allometrically scaled weight was included in the base model for central and peripheral volume of distribution (exponent 1) and for clearance and intercompartmental clearance (exponent 0.75). Model-estimated bioavailability of intramuscular ketamine was 41%. Dosing simulations suggest that doses of 2 mg/kg intravenously and 8 mg/kg or 6 mg/kg intramuscularly, depending on age, provide adequate sedation (plasma ketamine concentrations >750 ng/mL) for procedures lasting up to 20 minutes.

Pharmacokinetics of sildenafil in children with pulmonary arterial hypertension

BACKGROUND

Recently, sildenafil was introduced to treat pulmonary arterial hypertension (PAH); however, there are currently few studies on the pharmacokinetics of sildenalfil in children. Therefore, we aimed to carry out a pharmacokinetic study of sildenafil in children with PAH using a single dose.

METHODS

Twelve children diagnosed with PAH, consisting of with ten males and two females, were recruited for the study after obtaining written consent from their parents or guardians. Blood samples were obtained predose and at 0.25, 0.5, 1, 2, 4, 8 and 12 hours after the oral administration of 1 mg/kg of sildenafil using an extemporal pediatric formulation developed in our laboratory. The samples were analyzed using a previously validated high performance liquid chromatography method.

RESULTS

A pharmacokinetic analysis using the WinNonlin 3.1 program that considered the Akaike information criterion (AIC) for selecting a more adjustable model was performed. The following pharmacokinetic parameters were obtained: maximal concentration (C_max): 366±179 ng/mL, time to maximal concentration: 0.92±0.30 hours, elimination half-life (t_1/2): 2.41±1.18 hours, total clearance (CL_tot/F): 5.85±2.81 L/hour, volume of distribution (Vd/F): 20.13±14.5 L, absorption rate constants (Ka): 0.343 hour^-1, elimination rate (Ke): 0.35 hour^-1, area under curve from zero to infinity: 2061±618 ng/mL/hour. The data of all patients adjusted to the model of one compartment were corroborated using AIC.

CONCLUSIONS

The parameters Ka, Ke and t_1/2 were found to be similar to those reported in adults; however, the values of C_max and Vd/F were significantly higher. Based on these findings, we propose that treatment regimen of sildenafil be adjusted in children with PAH.

Pediatric Multiple Organ Dysfunction Syndrome: Promising Therapies

OBJECTIVE

To describe the state of the science, identify knowledge gaps, and offer potential future research questions regarding promising therapies for children with multiple organ dysfunction syndrome presented during the Eunice Kennedy Shriver National Institute of Child Health and Human Development Workshop on Pediatric Multiple Organ Dysfunction Syndrome (March 26-27, 2015).

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an expert from the field, issues relevant to the association of multiple organ dysfunction syndrome with a variety of conditions were presented, discussed, and debated with a focus on identifying knowledge gaps and research priorities.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by relevant literature.

CONCLUSIONS

Among critically ill children, multiple organ dysfunction syndrome is relatively common and associated with significant morbidity and mortality. For outcomes to improve, effective therapies aimed at preventing and treating this condition must be discovered and rigorously evaluated. In this article, a number of potential opportunities to enhance current care are highlighted including the need for a better understanding of the pharmacokinetics and pharmacodynamics of medications, the effect of early and optimized nutrition, and the impact of effective glucose control in the setting of multiple organ dysfunction syndrome. Additionally, a handful of the promising therapies either currently being implemented or developed are described. These include extracorporeal therapies, anticytokine therapies, antitoxin treatments, antioxidant approaches, and multiple forms of exogenous steroids. For the field to advance, promising therapies and other therapies must be assessed in rigorous manner and implemented accordingly.

Clinical Pharmacology Studies in Critically Ill Children

Developmental and physiological changes in children contribute to variation in drug disposition with age. Additionally, critically ill children suffer from various life-threatening conditions that can lead to pathophysiological alterations that further affect pharmacokinetics (PK). Some factors that can alter PK in this patient population include variability in tissue distribution caused by protein binding changes and fluid shifts, altered drug elimination due to organ dysfunction, and use of medical interventions that can affect drug disposition (e.g., extracorporeal membrane oxygenation and continuous renal replacement therapy). Performing clinical studies in critically ill children is challenging because there is large inter-subject variability in the severity and time course of organ dysfunction; some critical illnesses are rare, which can affect subject enrollment; and critically ill children usually have multiple organ failure, necessitating careful selection of a study design. As a result, drug dosing in critically ill children is often based on extrapolations from adults or non-critically ill children. Dedicated clinical studies in critically ill children are urgently needed to identify optimal dosing of drugs in this vulnerable population. This review will summarize the effect of critical illness on pediatric PK, the challenges associated with performing studies in this vulnerable subpopulation, and the clinical PK studies performed to date for commonly used drugs.

Use of Continuous Infusion Hydralazine in a Pediatric Patient on Mechanical Circulatory Support

Hydralazine is a direct peripheral arterial vasodilator used for acute hypertension. Usually administered as a bolus dose, continuous infusion has been described during pregnancy for preeclampsia and eclampsia and in limited reports in cardiac surgeries for afterload reduction. This case describes the use of continuous infusion hydralazine for afterload reduction in an infant receiving extracorporeal membrane oxygenation (ECMO) post-cardiac surgery. Postsurgery, the patient's mean arterial pressures (MAPs) could not be controlled despite escalating doses of vasodilatory medications including nitroprusside, nicardipine, and milrinone; hence, continuous infusion hydralazine was initiated. Although the initiation of a hydralazine infusion produced a decrease in MAP, the response was unsustainable. This case highlights an alternative method for managing systemic vascular resistance and cardiac output to allow for myocardial recovery after cardiac surgery and use of extracorporeal support. At the time of this writing, this is the first published case describing hydralazine administration via continuous infusion in pediatric patients. The use of continuous infusion hydralazine for afterload reduction provided a brief, non-sustained reduction in MAP in a post-cardiac surgery infant managed on ECMO support.

Sildenafil in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a life-threatening disease of varied etiologies. Although PAH has no curative treatment, a greater understanding of pathophysiology, technological advances resulting in early diagnosis, and the availability of several newer drugs have improved the outlook for patients with PAH. Sildenafil is one of the therapeutic agents used extensively in the treatment of PAH in children, as an off-label drug. In 2012, the United States Food and Drug Administration (USFDA) issued a warning regarding the of use high-dose sildenafil in children with PAH. This has led to a peculiar situation where there is a paucity of approved therapies for the management of PAH in children and the use of the most extensively used drug being discouraged by the regulator. This article provides a review of the use of sildenafil in the treatment of PAH in children.

Tailored tools to improve pharmacotherapy in infants

INTRODUCTION

Extensive within-population variability is the essence of neonatal pharmacology. Despite this, infants remain one of the last therapeutic orphans. Together with additional legal initiatives, tailoring of already available tools (modeling, covariates, pharmacovigilance) may significantly improve pharmacotherapy in infants.

AREAS COVERED

Modeling approaches that hold the promise to improve pharmacotherapy in infants are between-compound extrapolation for compounds that undergo the same route of elimination and integration of time-varying physiology to adapt for the fast maturational changes. Besides these maturational covariates (size, age), newly emerging covariates relate to novel treatment modalities (extracorporeal circulation, hypothermia), environmental issues (microbiome, critical illness) or pharmacogenetics. All these covariates interact with the maturational variation. Finally, pharmacovigilance also needs to be tailored to the characteristics of this population. This relates to preventive strategies, signal detection and assessment of causality.

EXPERT OPINION

Knowledge on pharmacotherapy in infants is lagging. Tailoring available tools to the specific characteristics (maturation) and clinical needs (newly emerging covariates) of infants is feasible but needs creativity and a multidisciplinary collaboration between modelers, academia, clinical researchers and, obviously, the public, including parents.

Paediatric pulmonary hypertension and sildenafil: current practice and controversies

In recent times, paediatric pulmonary arterial hypertension management has been transformed to focus on disease modifying strategies that improve both quality of life and survival, rather than just symptom palliation. Sildenafil, a phosphodiesterase-V inhibitor, has been at the centre of this. Despite controversial beginnings, its success in treating pulmonary arterial hypertension has led to its consideration for related pathologies such as persistent pulmonary hypertension of the newborn and bronchopulmonary dysplasia, as well as the development of a range of alternative formulations. However, this has caused its own controversy and confusion regarding the use of sildenafil in younger patients. In addition, recent data regarding long-term mortality and the repeal of US drugs approval have complicated the issue. Despite such setbacks, sildenafil continues to be a major component of the contemporary care of paediatric pulmonary hypertension in a variety of contexts, and this does not seem likely to change in the foreseeable future.

Pharmacokinetic changes in patients receiving extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a form of prolonged cardiopulmonary bypass used to temporarily sustain cardiac and/or respiratory function in critically ill patients. Extracorporeal membrane oxygenation further complicates the management of critically ill patients who already have profound physiologic derangements with consequent altered pharmacokinetics. The purpose of this study is to identify and critically review the published literature describing pharmacokinetics in the presence of ECMO. This review revealed a dearth of data describing pharmacokinetics during ECMO in critically ill adults, with most of the available data originating in neonates. Of concern, the present data indicate substantial variability and a lack of predictability in drug behavior in the presence of ECMO. The most common mechanisms by which ECMO affects pharmacokinetics are sequestration in the circuit, increased volume of distribution, and decreased drug elimination. While lipophilic drugs and highly protein-bound drugs (eg, voriconazole and fentanyl) are significantly sequestered in the circuit, hydrophilic drugs (eg, β-lactam antibiotics, glycopeptides) are significantly affected by hemodilution and other pathophysiologic changes that occur during ECMO. Although the published literature is insufficient to make any meaningful recommendations for adjusting therapy for drug dosing, this review systematically describes the available data enabling clinicians to make conclusions based on available data. Furthermore, this review serves to highlight the need for well-designed and conducted clinical and laboratory-based studies to provide the data from which robust dosing guidance can be developed to improve clinical outcomes in this most unwell cohort of patients.

Use of extracorporeal life support in adults with severe acute respiratory failure

Extracorporeal membrane oxygenation (ECMO) is a recognized and accepted therapeutic option in the treatment of neonatal and pediatric respiratory failure. However, early studies in adults did not demonstrate a survival benefit associated with the utilization of ECMO for severe acute respiratory failure. Despite this historical lack of benefit, use of ECMO in adult patients has seen a recent resurgence. Local successes and a recently published randomized trial have both demonstrated promising results in an adult population with high baseline mortality and limited therapeutic options. This article will review the history of ECMO use for respiratory failure; investigate the driving forces behind the latest surge in interest in ECMO for adults with refractory severe acute respiratory failure; and describe potential applications of ECMO that will likely increase in the near future.

A systematic review on pharmacokinetic changes in critically ill patients: role of extracorporeal membrane oxygenation

OBJECTIVE

Several factors including disease condition and different procedures could alter pharmacokinetic profile of drugs in critically ill patients. For optimizing patient's outcome, changing in dosing regimen is necessary. Extracorporeal Membrane Oxygenation (ECMO) is one of the procedures which could change pharmacokinetic parameters.The aim of this review was to evaluate the effect of ECMO support on pharmacokinetic parameters and subsequently pharmacotherapy.

METHOD

A systematic review was conducted by reviewing all papers found by searching following key words; extracorporeal membrane oxygenation, ECMO, pharmacokinetic and pharmacotherapy in bibliography database.

RESULTS

Different drug classes have been studied; mostly antibiotics. Almost all of the studies have been performed in neonates (as a case series). ECMO support is associated with altered pharmacokinetic parameters that may result in acute changes in plasma concentrations with potentially unpredictable pharmacological effect. Altreation in volume of distribution, protein binding, renal or hepatic clearance and sequestration of drugs by ECMO circuit may result in higher or lower doses requirement during ECMO. As yet, definite dosing guideline is not available. ECMO is extensively used recently for therapy and as a procedure affects pharmacokinetics profile along with other factors in critically ill patients. For optimizing the pharmacodynamic response and outcome of patients, drug regimen should be individualized through therapeutic drug monitoring whenever possible.