Evaluation of Altered Drug Pharmacokinetics in Critically Ill Adults Receiving Extracorporeal Membrane Oxygenation

Sedation management and processed EEG-based solutions during venovenous extracorporeal membrane oxygenation: a narrative review of key challenges and potential benefits

Extracorporeal membrane oxygenation (ECMO) is an established technique for managing severe cardiorespiratory failure. However, it is invasive and requires profound analgo-sedation during initiation and often throughout the therapy. Managing sedation in venovenous (VV) ECMO patients is particularly challenging due to the impact of ECMO circuits on pharmacokinetics and specific patient requirements. This can lead to unpredictable sedative effects and require multiple drugs at higher doses. Additionally, sedation is usually managed with traditional scoring methods, which are subjective and invalid during neuromuscular blockade. These uncertainties may impact outcomes. Recent clinical practice increasingly focuses on reducing sedation to enable earlier physiotherapy and mobilisation, particularly in patients awaiting transplants or receiving mechanical circulatory support. In this context, processed electroencephalogram-based (pEEG) sedation monitoring might be promising, having shown benefits in general anaesthesia and intensive care. However, the technology has limitations, and its benefits in ECMO practice have yet to be formally evaluated. This review provides insights into the challenges of ECMO sedation, including pharmacokinetics, unique ECMO requirements, and the implications of inadequate sedation scores. Finally, it includes a brief overview of the practicality and limitations of pEEG monitoring during VV-ECMO, highlighting a significant research gap.

Critical Care Pharmacology of Antiretroviral Therapy in Adults

The clinical pharmacology of antiretroviral therapy (ART) in critical care presents unique challenges due to the complex interplay between HIV infection, critical illness, and drug management. This comprehensive review examines the pharmacokinetic and pharmacodynamic considerations of antiretroviral drugs in critically ill patients, where altered absorption, distribution, metabolism, and excretion significantly impact drug effectiveness and safety. Critical illness can substantially modify drug pharmacokinetics through various mechanisms, including impaired gastrointestinal motility, fluid shifts, hypoalbuminemia, hepatic dysfunction, and altered renal function. These changes, combined with potential drug-drug interactions in the polypharmacy environment of intensive care units, necessitate careful consideration of dosing strategies and monitoring approaches. The review addresses specific challenges in various critical care scenarios, including management of ART in patients with organ dysfunction, during renal replacement therapy, and in special populations such as those with sepsis or acute respiratory distress syndrome. It also explores the role of therapeutic drug monitoring in optimizing antiretroviral therapy and managing drug toxicities in critical care settings. Emerging areas of research, including long-acting formulations, nanotechnology-based drug delivery systems, and personalized medicine approaches, are discussed as potential future directions for improving ART management in critical care. The review emphasizes the importance of a multidisciplinary approach involving critical care physicians, infectious disease specialists, and clinical pharmacists to optimize outcomes in this complex patient population. This review provides clinicians with practical guidance for managing ART in critically ill patients while highlighting areas requiring further research to enhance our understanding and improve patient care in this challenging setting.

Organ Utilization From Donors Following Extracorporeal Cardiopulmonary Resuscitation: A Systematic Review of Graft and Recipient Outcome

BACKGROUND

The global shortage of solid organs for transplantation is exacerbated by high demand, resulting in organ deficits and steadily growing waiting lists. Diverse strategies have been established to address this issue and enhance organ availability, including the use of organs from individuals who have undergone extracorporeal cardiopulmonary resuscitation (eCPR). The main aim of this work was to examine the outcomes for both graft and recipients of solid organ transplantations sourced from donors who underwent eCPR.

METHODS

We performed a systematic literature review using a combination of the terms related to extracorporeal life support and organ donation. Using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, PubMed and Scopus databases were searched up to February 2024.

RESULTS

From 1764 considered publications, 13 studies comprising 130 donors and 322 organ donations were finally analyzed. On average, included patients were 36 y old, and the extracorporeal life support was used for 4 d. Kidneys were the most often transplanted organs (68%; 220/322), followed by liver (22%; 72/322) and heart (5%; 15/322); with a very good short-term graft survival rate (95% for kidneys, 92% for lungs, 88% for liver, and 73% for heart). Four studies with 230 grafts reported functional outcomes at the 1-y follow-up, with graft losses reported for 4 hearts (36%), 8 livers (17%), and 7 kidneys (4%).

CONCLUSIONS

Following eCPR, organs can be successfully used with very high graft and recipient survival. In terms of meeting demand, the use of organs from patients after eCPR might be a suitable method for expanding the organ donation pool.

Systematic Review of Ex Vivo and In Vivo Pharmacokinetic Studies of Drugs Commonly Used During Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is a lifesaving treatment for critically ill patients in cardiac or respiratory failure refractory to conventional treatment. Patients on an ECMO circuit (pump, oxygenator, tubing) require numerous medications including sedatives, analgesics, cardioactive medications, and anticonvulsants. Currently, there are few dosing guidelines to optimize pharmacotherapy in this situation. A systematic review was conducted to describe pharmacokinetics (PK) of medications commonly used during ECMO. MEDLINE, Embase, Cochrane, BIOSIS, PubMed, and Web of Science databases were searched. All articles presenting ex vivo, animal, and human data on the PK of the subject medications in the ECMO circuit were included. Three authors independently examined citation titles and abstracts. Four authors extracted relevant details from included studies into standardized data extraction forms. Methodological quality was assessed using the ClinPK guidelines and the Joanna Briggs Institute Checklist. Forty-four studies examining 30 medications were included, 26 ex vivo studies (mostly adult circuits) and 18 observational studies (mainly neonatal patients). Pharmacokinetics varied depending on the medication's characteristics, study type, and population. Study quality was variable, limiting the possibility of deriving hard dosing guidelines from this available literature. Further population PK studies are needed to adequately determine dosing guidelines in adults and children requiring ECMO.

Pharmacokinetic Changes and Influencing Factors of Polymyxin B in Different ECMO Modes

Purpose

With the development of extracorporeal membrane oxygenation (ECMO) technology, the duration of ECMO support has gradually increased, leading to an increased risk of ECMO-related bacterial resistance. Polymyxin B (PMB) is used to treat drug-resistant bacterial infections. However, the pharmacokinetic (PK) parameters of antibiotics may change during ECMO, resulting in over- or under-exposure. This study aimed to clarify the changes in PK parameters and identify factors influencing PMB levels in patients receiving venovenous or venoarterial ECMO.

Patients and Methods

A prospective PK study was performed in 11 patients receiving ECMO with resistant bacteria. After reaching a steady state, the drug concentrations of PMB pre- and post-oxygenator were measured. Nonlinear mixed-effects modelling was used to construct a population PK model for PMB. Microbial results were assessed using repeated cultures at the end of treatment. Semiquantitative microbial culture results were used to form clearance and uncleared groups.

Results

The PMB concentrations were not significantly different between pre- and post-oxygenator. A two-compartment model best described the PK of PMB. ECMO flow rate was included as a covariate of clearance (CL). Continuous renal replacement therapy (CRRT) were included as covariates on the volume of the central compartment. The PK parameters central compartment, volume of the peripheral compartment, CL, and inter-compartmental clearance or flow rate(Q) were 20.41 L, 9.86 L, 3.75 L/h, and 3.82 L/h. 7 patients (63.64%) had two consecutive negative bacterial cultures at discharge. The Css,avg shows a significant difference between clearance group (2.26±0.72) and uncleared group (1.25±0.24), P<0.05.

Conclusion

There were no significant differences in PMB concentrations between pre- and post-oxygenator. The PK of PMB may be altered in patients receiving CRRT-ECMO. The ECMO flow rate is strongly correlated with the CL. The Css,avg is correlated with the bacterial clearance rate. In clinical practice, increasing the incidence of therapeutic drug monitoring may improve the clinical outcomes.

The Effect of Extracorporeal Membrane Oxygenation on the Pharmacokinetics of Dexmedetomidine Hydrochloride

OBJECTIVES

Our objective was to explore the effects of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics of dexmedetomidine hydrochloride via vitro and in vivo experiments DESIGN: A single-center animal investigation.

SETTING

An experimental animal facility in a tertiary hospital.

PARTICIPANTS

Eighteen male Landrace pigs.

INTERVENTIONS

For the in vitro experiment, ECMO circuits were primed with whole blood solutions of dexmedetomidine at different concentrations and ran ex vivo. The adsorption rates of dexmedetomidine hydrochloride in ECMO circuits and control glass tubes were compared at 60 minutes, 5 hours, and 10 hours after the start of the in vitro experiment. In the in vivo experiment, 12 Landrace pigs were randomly allocated to the venovenous ECMO group or the control group. Dexmedetomidine hydrochloride (1 μg/kg) was administered to both groups. Blood samples were collected at 0 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 45 minutes, 60 minutes, 90 minutes, 2 hours, 3 hours, 5 hours, 7 hours, and 10 hours after administration. The plasma concentrations of dexmedetomidine were measured, and pharmacokinetic analysis was conducted in both groups.

MEASUREMENTS AND MAIN RESULTS

The results revealed no significant difference in adsorption rates of dexmedetomidine hydrochloride in ECMO circuits at 60 minutes and 5 hours, but differences were observed at 10 hours. In vivo experiment, pharmacokinetic analysis revealed no significant difference in the area under the curve (AUC0-t), AUC0-∞, distribution half-life, elimination half-life, clearance, apparent volume of distribution, mean residence time or peak drug concentrations between the 2 groups (p > 0.05).

CONCLUSIONS

The ECMO circuit had an adsorption effect on dexmedetomidine hydrochloride, but this effect was not sufficient to impact the in vivo pharmacokinetics of dexmedetomidine significantly. The effect of ECMO on the pharmacokinetics of dexmedetomidine hydrochloride was not significant.

Beta-Lactam Antibiotic Exposure During Pediatric Extracorporeal Membrane Oxygenation: Retrospective Cohort Analysis of Drug Levels Using Standard Dosing, 2018-2020

OBJECTIVES

Children on extracorporeal membrane oxygenation (ECMO) are at high risk of infection that may worsen prognosis. Even though treatment with beta-lactam antibiotics is frequent, dosing is not adapted to altered pharmacokinetic and pharmacodynamic characteristics of children on ECMO. There is, therefore, a risk of inadequate drug levels when using standard dosing. In this study, we aimed to describe beta-lactam exposures of children on ECMO using current dosing and to identify factors associated with inadequate exposure. The optimal pharmacokinetic/pharmacodynamic target was considered as a plasma concentration four times above the minimum inhibitory concentration throughout the dosing interval target.

DESIGN

Two-center retrospective cohort study.

SETTING

Two PICUs in Paris, France.

PATIENTS

Children (from birth to 18 yr) undergoing venovenous or venoarterial ECMO, from 2018 to 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 57 patients who received 11 different beta-lactams, with 226 plasma concentrations analyzed. A total of 32 infections were documented. Overall, 133 of 226 concentrations (58.8%) were insufficient, primarily in samples from children younger than 28 days (p = 0.035), with low body weight (p = 0.013), or in instances of hypoalbuminemia (p = 0.011) and increased renal clearance (p = 0.032). Supratherapeutic concentrations were observed in 25 of 226 samples (11.1%), associated with being taken from patients with renal impairment (p < 0.01).

CONCLUSIONS

In this retrospective cohort of pediatric ECMO cases, there is an associated risk of underexposure when prescribing conventional dosing of beta-lactams, which are likely associated with renal impairment and fluid overload. Prospective testing of therapeutic drug monitoring combined with pharmacokinetic/pharmacodynamic models should be tested as a risk-reduction strategy in this vulnerable population.

Impact of Extracorporeal Membrane Oxygenation (ECMO) on Serum Concentrations of Cefepime

ECMO is becoming widely used as a life-saving measure for critically ill patients. However, there is limited data on pharmacokinetics and the dosing of beta-lactam antibiotics in ECMO. In this study, we evaluated the serum concentrations of cefepime in patients on ECMO to determine the impact of ECMO circuitry and to guide therapeutic dosing. Methods: Patients 19 years or older admitted to the ICU, treated with ECMO and beta-lactam antibiotics for presumed or documented infection, were enrolled. Three blood samples (peak, midpoint, trough) were obtained before ECMO (pre-ECMO) and during ECMO (intra-ECMO) at a steady state. Results: Eight patients met inclusion criteria; six received cefepime. All patients were male. Average ± SD age was 45.8 ± 14.7. Four patients received ECMO for severe SARS-CoV-2 infection, and one each for Pneumocystis pneumonia and influenza A infection. Mean ± SD APACHE II and SOFA scores prior to ECMO were 24.6 ± 7.1 and 11.0 ± 3.9, respectively. All but one of the patients received venovenous (VV) ECMO. Cefepime 1 g every 6 h intravenously over 2 min was administered to all patients before and during ECMO. Cefepime concentrations were fit to non-compartment analysis (NCA) and area under the serum concentration-time curve averaged ± SE 211.9 ± 29.6 pre-ECMO and 329.6 ± 32.3 mg*h/L intra-ECMO, p = 0.023. No patients displayed signs of cefepime neurotoxicity. Patients received ECMO for 43.1± 30 days. All patients expired. Cefepime dosed at 1 g every 6 h intravenously appears to achieve therapeutic levels for critically ill patients on ECMO.

The impact of extracorporeal support on antimicrobial pharmacokinetics in critically ill neonatal and paediatric patients: A systematic review

OBJECTIVES

Infections represent a major risk for critically ill neonatal and paediatric patients requiring extracorporeal life-saving support such as extracorporeal membrane oxygenation (ECMO) and/or continuous renal replacement therapies (CRRT). Patient outcomes rely on achieving target antimicrobial concentrations. In critically ill adults on extracorporeal support, suboptimal antimicrobial concentrations have been shown to be common. Our objective was to systematically review antimicrobial pharmacokinetic studies in critically ill term neonatal and paediatric patients receiving ECMO and/or CRRT and compare them to similar cohorts of patients not receiving ECMO or CRRT.

METHODS

Studies published between 1990 and 2022 were identified through systematic searches in PUBMED, Embase, Web of Science, Medline, Google Scholar and CINAHL. Studies were included which provided antimicrobial pharmacokinetic parameters (volume of distribution and clearance) in the neonatal and paediatric patients receiving ECMO and/or CRRT. Studies were excluded if no antimicrobial pharmacokinetic parameters were described or could be calculated.

RESULTS

Forty-four pharmacokinetic studies were identified describing 737 patients, with neonatal patients recruited in 70% of the ECMO studies and <1% of the CRRT studies. Of all the studies, 50% were case reports or case series. The pharmacokinetics were altered for gentamicin, daptomycin, ceftolozane, micafungin, voriconazole, cefepime, fluconazole, piperacillin, and vancomycin, although considerable patient variability was described.

CONCLUSION

Significant gaps remain in our understanding of the pharmacokinetic alterations in neonatal and paediatric patients receiving ECMO and CRRT support.

A pharmacokinetic framework describing antibiotic adsorption to cardiopulmonary bypass devices

Cardiopulmonary bypass (CPB) can alter pharmacokinetic (PK) parameters and the drug may adsorb to the CPB device, altering exposure. Cefazolin is a beta-lactam antibiotic used for antimicrobial prophylaxis during cardiac surgery supported by CPB. Adsorption of cefazolin could result in therapeutic failure. An ex vivo study was undertaken using CPB devices primed and then dosed with cefazolin and samples were obtained over 1 hour of recirculation. Twelve experimental runs were conducted using different CPB device sizes (neonate, infant, child, and adult), device coatings (Xcoating™, Rheoparin®, PH.I.S.I.O), and priming solutions. The time course of saturable binding, using Bmax (binding capacity), Kd (dissociation constant), and T2off (half-time of dissociation), described cefazolin adsorption. Bmax estimates for the device sizes were neonate 40.0 mg (95% CI 24.3, 67.4), infant 48.6 mg (95% CI 5.97, 80.2), child 77.8 mg (95% CI 54.9, 103), and adult 196 mg (95% CI 191, 199). The Xcoating™ Kd estimate was 139 mg/L (95% CI 27.0, 283) and the T2off estimate was 98.4 min (95% CI 66.8, 129). The Rheoparin® and PH.I.S.I.O coatings had similar binding parameters with Kd and T2off estimates of 0.169 mg/L (95% CI 0.01, 1.99) and 4.94 min (95% CI 0.17, 59.4). The Bmax was small (< 10%) relative to a typical total patient dose during cardiac surgery supported by CPB. A dose adjustment for cefazolin based solely on drug adsorption is not required. This framework could be extended to other PK studies involving CPB.

Role of VV ECMO tracheal surgery and carinal resection: Two case reports

The aim of this study is to describe the anaesthesia management of two patients undergoing carinal resection under veno-venous extracorporeal membrane oxygenation (VV ECMO). In both cases, anaesthesia was induced and then maintained with inhalational agents during pneumonectomy and mediastinoscopy (respectively). Then the jugular and femoral veins were cannulated and VV ECMO was started after heparinization. One of the patients presented bleeding during surgery, which was treated with low-dose vasopressors (norepinephrine) and transfusion of platelets, fresh frozen plasma, and concentrated red blood cells. During VV ECMO, anaesthesia was maintained with target-controlled infusion of propofol. VV ECMO can be expected to improve surgical conditions in tracheal surgery; however, it is still a novel technique in this context. In selected patients, it would guarantee ventilatory support during carinal resection, but it is essential to carefully plan anaesthesia maintenance and prepare for VV ECMO-related complications. This technique should only be used in tertiary centres with experience in VV ECMO management.

Ketamine Use in Adult and Pediatric Patients Receiving Extracorporeal Membrane Oxygenation (ECMO): A Systematic Review

Background: Analgesia and sedation are often critical elements of therapy for patients undergoing extracorporeal membrane oxygenation (ECMO). Aside from potential drug-drug interactions, the PK changes associated with ECMO make appropriate analgosedative selection challenging. Ketamine is less lipophilic and has lower protein binding than alternative agents, and may be less impacted by the PK changes during ECMO. Objective: To systematically identify all instances of ketamine use during ECMO support in the literature to elucidate associated efficacy and safety outcomes and prevalence of use, as well as commonly used dosing strategies and pharmacokinetic data. Methods: Web of Science, Cochrane Library, Scopus, Ovid MEDLINE, PubMed, and OVID Embase were searched through 02/2023 using keywords ketamine and ECMO or extracorporal life support (ECLS). Case reports, case series, and studies were included that had (1) original data, (2) included patients that were on ECMO and continuous infusion ketamine, and (3) reported pertinent ketamine related clinical endpoints or prevalence of use. Results: Of the 307 articles screened, 25 were identified as relevant and 11 met our inclusion criteria. Heterogeneity of patient population, ketamine indication, reported outcomes, and reported safety endpoints were identified in the included articles. Commonly reported information includes indications, pharmacokinetics, dosing, adverse effects and use in pediatrics for ketamine, and suspected opioid sparing effect. Conclusion: Our review has found a lack of consistency in reporting and results in adult and pediatric patients. Increased consistency in reporting and larger studies are required to increase our knowledge of ketamine use in both the adult and pediatric patient population.

Antimicrobial Pharmacokinetic Considerations in Extracorporeal Membrane Oxygenation

Critical illness creates challenges for healthcare providers in determining the optimal treatment of severe disease, particularly in determining the most appropriate selection and dosing of medications. Critically ill patients experience endogenous physiologic changes that alter the pharmacokinetics (PKs) of medications. These alterations can be further compounded by mechanical support modalities such as extracorporeal membrane oxygenation (ECMO). Specific components of the ECMO circuit have the potential to affect drug PKs through drug sequestration and an increase in the volume of distribution. Factors related to the medications themselves also play a role. These PK alterations create problems when trying to properly utilize antimicrobials in this patient population. The literature seeking to identify appropriate antimicrobial dosing regimens is both limited and difficult to evaluate due to patient variability and an inability to determine the exact role of the ECMO circuit in reduced drug concentrations. Lipophilic and highly protein bound medications are considered more likely to undergo significant drug sequestration in an ECMO circuit, and this general trend represents a logical starting point in antimicrobial selection and dosing in patients on ECMO support. This should not be the only consideration, however, as identifying infection and evaluating the efficacy of treatments in this population is challenging. Due to these challenges, therapeutic drug monitoring should be utilized whenever possible, particularly in cases with severe infection or high concern for drug toxicity.

COVID-19 Drug Treatments Are Prone to Sequestration in Extracorporeal Membrane Oxygenation Circuits: An Ex Vivo Extracorporeal Membrane Oxygenation Study

Drug treatments for coronavirus disease 2019 (COVID-19) dramatically improve patient outcomes, and although extracorporeal membrane oxygenation (ECMO) has significant use in these patients, it is unknown whether ECMO affects drug dosing. We used an ex vivo adult ECMO model to measure ECMO circuit effects on concentrations of specific COVID-19 drug treatments. Three identical ECMO circuits used in adult patients were set up. Circuits were primed with fresh human blood (temperature and pH maintained within normal limits). Three polystyrene jars with 75 ml fresh human blood were used as controls. Remdesivir, GS-441524, nafamostat, and tocilizumab were injected in the circuit and control jars at therapeutic concentrations. Samples were taken from circuit and control jars at predefined time points over 6 h and drug concentrations were measured using validated assays. Relative to baseline, mean (± standard deviation [SD]) study drug recoveries in both controls and circuits at 6 h were significantly lower for remdesivir (32.2% [±2.7] and 12.4% [±2.1], p < 0.001), nafamostat (21.4% [±5.0] and 0.0% [±0.0], p = 0.018). Reduced concentrations of COVID-19 drug treatments in ECMO circuits is a clinical concern. Remdesivir and nafamostat may need dose adjustments. Clinical pharmacokinetic studies are suggested to guide optimized COVID-19 drug treatment dosing during ECMO.

Impact of Extracorporeal Membrane Oxygenation Circuitry on Remdesivir

OBJECTIVES

This study aimed to determine the oxygenator impact on alterations of remdesivir (RDV) in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch) extracorporeal membrane -oxygenation (ECMO) circuit including the Quadrox-i oxygenator.

METHODS

One-quarter-inch and a 3/8-inch, simulated closed-loop ECMO circuits were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. Additionally, 1/4-inch and 3/8-inch circuits were also prepared without an oxygenator in series. A 1-time dose of RDV was administered into the circuits and serial preoxygenator and postoxygenator concentrations were obtained at 0 to 5 minutes, and 1-, 2-, 3-, 4-, 5-, 6-, 8-, 12-, and 24-hour time points. The RDV was also maintained in a glass vial and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation.

RESULTS

For the 1/4-inch circuits with an oxygenator, there was a 35% to 60% RDV loss during the study period. For the 1/4-inch circuits without an oxygenator, there was a 5% to 20% RDV loss during the study period. For the 3/8-inch circuit with and without an oxygenator, there was a 60% to 70% RDV loss during the study period.

CONCLUSIONS

There was RDV loss within the circuit during the study period and the RDV loss was more pronounced with the larger 3/8-inch circuit when compared with the 1/4-inch circuit. The impact of the -oxygenator on RDV loss appears to be variable and possibly dependent on the size of the circuit and -oxygenator. These preliminary data suggest RDV dosing may need to be adjusted for concern of drug loss via the ECMO circuit. Additional single- and multiple-dose studies are needed to validate these findings.

No Sequestration of Commonly Used Anti-Infectives in the Extracorporeal Membrane Oxygenation (ECMO) Circuit-An Ex Vivo Study

Patients undergoing extracorporeal membrane oxygenation (ECMO) often require therapy with anti-infective drugs. The pharmacokinetics of these drugs may be altered during ECMO treatment due to pathophysiological changes in the drug metabolism of the critically ill and/or the ECMO therapy itself. This study investigates the latter aspect for commonly used anti-infective drugs in an ex vivo setting. A fully functional ECMO device circulated an albumin-electrolyte solution through the ECMO tubes and oxygenator. The antibiotic agents cefazolin, cefuroxim, cefepime, cefiderocol, linezolid and daptomycin and the antifungal agent anidulafungin were added. Blood samples were taken over a period of four hours and drug concentrations were measured via high-pressure liquid chromatography (HPLC) with UV detection. Subsequently, the study analyzed the time course of anti-infective concentrations. The results showed no significant changes in the concentration of any tested anti-infectives throughout the study period. This ex vivo study demonstrates that the ECMO device itself has no impact on the concentration of commonly used anti-infectives. These findings suggest that ECMO therapy does not contribute to alterations in the concentrations of anti-infective medications in severely ill patients.

Candidemia in Adult Patients in the ICU: A Reappraisal of Susceptibility Testing and Antifungal Therapy

OBJECTIVE

To provide updates on the epidemiology and recommendations for management of candidemia in patients with critical illness.

DATA SOURCES

A literature search using the PubMed database (inception to March 2023) was conducted using the search terms "invasive candidiasis," "candidemia," "critically ill," "azoles," "echinocandin," "antifungal agents," "rapid diagnostics," "antifungal susceptibility testing," "therapeutic drug monitoring," "antifungal dosing," "persistent candidemia," and "Candida biofilm."

STUDY SELECTION/DATA EXTRACTION

Clinical data were limited to those published in the English language. Ongoing trials were identified through ClinicalTrials.gov.

DATA SYNTHESIS

A total of 109 articles were reviewed including 25 pharmacokinetic/pharmacodynamic studies and 30 studies including patient data, 13 of which were randomized controlled clinical trials. The remaining 54 articles included fungal surveillance data, in vitro studies, review articles, and survey data. The current 2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the Management of Candidiasis provides recommendations for selecting empiric and definitive antifungal therapies for candidemia, but data are limited regarding optimized dosing strategies in critically ill patients with dynamic pharmacokinetic changes or persistent candidemia complicated.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Outcomes due to candidemia remain poor despite improved diagnostic platforms, antifungal susceptibility testing, and antifungal therapy selection for candidemia in critically ill patients. Earlier detection and identification of the species causing candidemia combined with recognition of patient-specific factors leading to dosing discrepancies are crucial to improving outcomes in critically ill patients with candidemia.

CONCLUSIONS

Treatment of candidemia in critically ill patients must account for the incidence of non-albicans Candida species and trends in antifungal resistance as well as overcome the complex pathophysiologic changes to avoid suboptimal antifungal exposure.

Cefepime pharmacokinetics in adult extracorporeal membrane oxygenation patients

BACKGROUND

The impact of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics/dynamics (PK/PD) of beta-lactam antibiotics have not been well studied in general, but cefepime specifically has the least amount of data. We aimed to investigate whether ECMO alters the PK of cefepime in adult intensive care unit (ICU) patients.

METHODS

This single-center, retrospective case-control study evaluated cefepime therapeutic drug monitoring (TDM) results from ECMO patients that were matched 1:1 with TDM results in non-ECMO patients for drug regimen and renal function. The primary outcome was the difference in PK/PD of cefepime in ECMO compared with non-ECMO ICU patients. Secondary outcomes included hospital length of stay, treatment failure, superinfection, bacterial resistance, and survival to discharge.

RESULTS

Eighty-two patients were included with 44 matched cefepime concentrations in each group. ECMO patients had higher free maximum concentrations (fCmax) (p = 0.003), lower free minimum concentration (fCmin)/1x minimum inhibitory concentration (MIC) ratios (p = 0.040), and lower attainment of free Cmin/4x MIC (p = 0.010). There were no differences between the groups for free Cmin, time above 1xMIC or 4x MIC, and pharmacokinetic parameters (ke, half-life, and Vd). Of those who survived to discharge, hospital length of stay was longer in the ECMO group (p < 0.001). Patients on ECMO were more likely to experience treatment failure (p = 0.036). The incidence of bacterial resistance, superinfection, or survival were similar among the groups.

CONCLUSION

These data suggest that more aggressive empiric dosing may be warranted in patients on ECMO. Therapeutic drug monitoring and future prospective studies would provide more evidence to guide decision making regarding dose adjustments.

Validated HPLC-UV method for amphotericin B quantification in a critical patient receiving AmBisome and treated with extracorporeal replacement therapies

Amphotericin B (AMB) is a polyene macrolide antifungal agent used for treating invasive fungal infections. Liposomal AMB is a lipid dosage form, available as AmBisome, which reduces the toxicity of the drug. A simple HPLC-UV method was developed for the determination of AMB in plasma to study its pharmacokinetic profile in a critical patient receiving AmBisome and treated with extracorporeal replacement therapies. Sample preparation was performed using plasma deproteinization and drug release from liposome by the addition of acetonitrile (ACN)/zinc sulfate and ultrasonication. Chromatographic separation was performed using a C18 column and a mobile phase consisting of phosphate buffer (pH 3.0)/ACN (65/35, v/v). The UV detector was set at 407 nm. The total run time analysis was 23 min. The method was validated according to the standard guidelines and applied to study the pharmacokinetics of AMB in a critical patient. The total run time analysis obtained was shorter than that of the previously reported methods, being useful for therapeutic drug monitoring or pharmacokinetic profile research.

Pharmacokinetics of Commonly Used Antimicrobials in Critically Ill Pediatric Patients During Extracorporeal Membrane Oxygenation: A Systematic Review

PURPOSE

Adequate dosing of antimicrobials is critical to properly treat infections and limit development of resistance and adverse effects. Limited guidance exist for antimicrobial dosing adjustments in patients requiring extracorporeal membrane oxygenation (ECMO) therapy, particularly in the pediatric population. A systematic review was conducted to delineate the pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobials in critically ill neonates and children requiring ECMO therapy.

METHODS

Medline, EMBASE, Global Health and All EBM Reviews databases were queried. Grey literature was examined. All clinical studies reporting PK/PD parameters of antimicrobials in critically ill pediatric patients treated with ECMO were included, except for case reports and congress abstracts. Two independent reviewers applied the inclusion and exclusion criteria. Reviewers were then paired to independently extract data and evaluate the methodological quality of studies using the ROBINS-I tool and the compliance with ClinPK reporting guidelines. Patient and study characteristics, key PK/PD findings, details of ECMO circuits and co-treatments were summarized qualitatively. Broad dosing recommendations were formulated based on the available data for specific antimicrobials.

RESULTS

Twenty-nine clinical studies were included; most were observational and uncontrolled. Patient characteristics and co-treatments were often missing. The effect of ECMO on PK/PD parameters of antimicrobials varied depending on the drugs and population studied. It was only possible to formulate dosing recommendations for a few antimicrobials given the paucity of data, its overall low quality and heterogeneity in reporting.

CONCLUSION

Limited data exists on the PK/PD of antimicrobials during ECMO therapy in the pediatric population. Rigorously designed population PK studies are required to establish empiric dosing guidelines for antimicrobials in patients requiring this therapeutic modality. The use of therapeutic drug monitoring for antimicrobials in pediatric patients on ECMO should be encouraged to optimize dosing.

TRIAL REGISTRY

PROSPERO registration number: CRD42018099992 (Registered: July 24th 2018).

Pharmacokinetics of ampicillin during venovenous extracorporeal membrane oxygenation: A case report

The presence of extracorporeal membrane oxygenation (ECMO) in addition to underlying critical illness can affect the pharmacokinetics and pharmacodynamics of drugs that are often required to treat this patient population. While ampicillin is the preferred agent for the treatment of susceptible Enterococcus faecalis infections, there are no in vivo pharmacokinetic studies regarding ampicillin dosing in patients receiving ECMO. This case report consists of two patients on venovenous ECMO with E. faecalis bloodstream infections in which ampicillin serum concentrations were measured. Pharmacokinetic parameters were calculated using a one compartment open model. Ampicillin trough levels were 5.87 and 39.2 mg/L for patients A and B, respectively. Based on these results, ampicillin concentrations were found to be above the minimum inhibitory concentration (MIC) for 100% of the dosing interval. The findings of this case report demonstrate that therapeutic concentrations of ampicillin can be obtained in patients on ECMO and therapeutic drug monitoring can be utilized to ensure adequate serum concentrations are achieved.

Antifungal Dosing in Critically Ill Patients on Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is an established advanced life support system, providing temporary cardiac and/or respiratory support in critically ill patients. Fungal infections are associated with increased mortality in patients on ECMO. Antifungal drug dosing for critically ill patients is highly challenging because of altered pharmacokinetics (PK). PK changes during critical illness; in particular, the drug volume of distribution (Vd) and clearance can be exacerbated by ECMO. This article discusses the available literature to inform adequate dosing of antifungals in this patient population. The number of antifungal PK studies in critically ill patients on ECMO is growing; currently available literature consists of case reports and studies with small sample sizes providing inconsistent findings, with scant or no data for some antifungals. Current data are insufficient to provide definitive empirical drug dosing guidance and use of dosing strategies derived from critically patients not on ECMO is reasonable. However, due to high PK variability, therapeutic drug monitoring should be considered where available in critically ill patients receiving ECMO to prevent subtherapeutic or toxic antifungal exposures.

Therapeutic Drug Monitoring of Antimicrobials in Critically Ill Obese Patients

Obesity is a significant global public health concern that is associated with an elevated risk of comorbidities as well as severe postoperative and nosocomial infections. The treatment of infections in critically ill obese patients can be challenging because obesity affects the pharmacokinetics and pharmacodynamics of antibiotics, leading to an increased risk of antibiotic therapy failure and toxicity due to inappropriate dosages. Precision dosing of antibiotics using therapeutic drug monitoring may help to improve the management of this patient population. This narrative review outlines the pharmacokinetic and pharmacodynamic changes that result from obesity and provides a comprehensive critical review of the current available data on dosage adjustment of antibiotics in critically ill obese patients.

Oxygenator impact on peramivir in extra-corporeal membrane oxygenation circuits

INTRODUCTION

This study aims to determine the oxygenator impact on alterations of peramivir (PRV) in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch) extra-corporeal membrane oxygenation (ECMO) circuit including the Quadrox-i^® oxygenator.

METHODS

1/4-inch and 3/8-inch, simulated closed-loop ECMO circuits were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. Additionally, 1/4-inch and 3/8-inch circuits were also prepared without an oxygenator in series. A one-time dose of PRV was administered into the circuits and serial pre- and post-oxygenator concentrations were obtained at 5-min and 1-, 2-, 3-, 4-, 5-, 6-, 8-, 12-, and 24-h time points. PRV was also maintained in a glass vial, and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation.

RESULTS

For the 1/4-in. circuit with an oxygenator, there was < 15% PRV loss, and for the 1/4-in. circuit without an oxygenator, there was < 3% PRV loss during the study period. For the 3/8-in. circuits with an oxygenator, there was < 15% PRV loss, and for the 3/8-in. circuits without an oxygenator, there was < 3% PRV loss during the study period.

CONCLUSION

There was no significant PRV loss over the 24-h study period in either the 1/4-in. or 3/8-in circuit, regardless of the presence of the oxygenator. The concentrations obtained pre- and post-oxygenator appeared to approximate each other, suggesting there may be no drug loss via the oxygenator. This preliminary data suggests PRV dosing may not need to be adjusted for concern of drug loss via the oxygenator. Additional single and multiple dose studies are needed to validate these findings.

The Influence of Extracorporeal Membrane Oxygenation on Antibiotic Pharmacokinetics

Extracorporeal membrane oxygenation (ECMO) is becoming increasingly utilized to support critically ill patients who experience life-threatening cardiac or pulmonary compromise. The provision of this intervention poses challenges related to its complications and the optimization of medication therapy. ECMO's mechanical circulatory support is facilitated via various devices and equipment that have been shown to sequester lipophilic- and protein-bound medications, including anti-infectives. Since infectious outcomes are dependent on achieving specific anti-infectives' pharmacodynamic targets, the understanding of these medications' pharmacokinetic parameters in the setting of ECMO is important to clinicians. This narrative, non-systematic review evaluated the findings of the most recent and robust pharmacokinetic analyses for commonly utilized anti-infectives in the setting of ECMO. The data from available literature indicates that anti-infective pharmacokinetic parameters are similar to those observed in other non-ECMO critically ill populations, but considerable variability in the findings was observed between patients, thus prompting further evaluation of therapeutic drug monitoring in this complex population.

Comparison of Standard-Dose Versus High-Dose Dexmedetomidine in Extracorporeal Membrane Oxygenation

BACKGROUND

Dexmedetomidine is commonly used to achieve light sedation in patients on extracorporeal membrane oxygenation (ECMO) despite minimal evidence. In vivo studies have shown dexmedetomidine sequestration in ECMO circuits, and higher doses may be used to overcome sequestration.

OBJECTIVE

The purpose of this study was to compare safety and efficacy of dexmedetomidine at standard versus high doses in ECMO.

METHODS

A retrospective analysis of adult ECMO patients was performed. Patients were compared as receiving either standard-dose (≤1.5 µg/kg/h) or high-dose (>1.5 µg/kg/h) dexmedetomidine. Safety outcomes included new onset bradycardia or hypotension. Efficacy was compared by the addition of concomitant sedative and analgesic agents.

RESULTS

One hundred five patients were evaluated, with 20% of patients in the high-dose group. Comparing standard and high dosing, no significant differences were seen in primary safety outcomes including bradycardia (49% vs 38%, P = 0.46), hypotension (79% vs 71%, P = 0.56), or addition of vasopressors (75% vs 71%, P = 0.78). Need for concomitant analgesic agents and propofol was similar between groups.

CONCLUSION AND RELEVANCE

This represents the first evaluation of use of high-dose dexmedetomidine in ECMO. Rates of dexmedetomidine higher than 1.5 µg/kg/h were commonly used in patients on ECMO, with similar rates of adverse effects and need for concomitant propofol and analgesic agents. While high-dose dexmedetomidine may be as safe as standard dose, no additional efficacy was found.

Medical nutrition therapy in patients receiving ECMO: Evidence-based guidance for clinical practice

Patients receiving extracorporeal membrane oxygenation (ECMO) inherit substantial disease-associated metabolic, endocrinologic, and immunologic modifications. Along with the technical components of ECMO, the aforementioned alterations may affect patients' needs and feasibility of adequate macronutrient and micronutrient supply and intake. Thus, patients receiving ECMO are at increased risk for iatrogenic malnutrition and require targeted individual medical nutrition therapy (MNT). However, specific recommendations for MNT in patients receiving ECMO are limited and, with some exceptions, based on an evidence base encompassing general patients who are critically ill. Consequently, clinician decision-making for MNT in patients receiving ECMO is unguided, which may further increase nutrition risk, culminating in iatrogenic malnutrition and ultimately affecting patient outcomes. The purpose of this article is to provide educational background and highlight specific points for MNT in adult patients receiving ECMO, which might serve as evidence-based guidance to develop institutional standard operating procedures and nutrition protocols for daily clinical practice.

Linezolid pharmacokinetics: a systematic review for the best clinical practice

OBJECTIVES

To summarize the pharmacokinetics of linezolid to optimize the dosing regimen in special populations.

METHODS

A literature search was performed in three largest medical databases, including Embase, Scopus, and PubMed. The main applied keywords were linezolid and pharmacokinetics. Of 3663 retrieved publications in the English language, 35 original research articles, clinical studies, and case reports about linezolid pharmacokinetics in different populations such as pregnant women, pediatrics, elderly subjects, obese people, individuals with organ dysfunction, and critically ill patients were included. RESULTS AND CONCLUSION: Dose adjustment is not currently recommended for linezolid in patients with mild to moderate renal or hepatic impairment, older adults, and pregnant women. Although dose adjustment is not recommended in patients with severe renal or hepatic impairment, it should be considered that these patients are more vulnerable to linezolid adverse effects and drug interactions. In pediatrics, reducing the linezolid dosing interval to 8 h is suggested. Despite the lack of sufficient information in obese individuals, dosing based on body weight or use of higher dose seems to be justifiable to prevent sub-therapeutic concentrations. Although dose adjustment of linezolid is not recommended in critically ill patients, administration of linezolid as continuous intravenous infusion is suggested in this population. Blood level monitoring should be considered in populations that are vulnerable to linezolid underexposure (such as critically ill patients with augmented renal clearance, pediatrics, overweight, and obese patients) or overexposure (such as elderly, patients with hepatic and renal impairment). To assess the efficacy and safety of linezolid, the area under the concentration-time curve over 24 h to minimum inhibitory concentration (AUC0-24 h/MIC) equal to 80-120, percentage of time above the MIC ≥ 85%, and serum trough concentration between 2 and 7 mg/L are suggested.

Pharmacology of Drugs and Their Kinetics and Dynamicity during Extracorporeal Life Support

ECMO/ECLS is now a days very common modality for saving patient life in ICU. ECMO is unphysiological circulation which hampers the multiorgan function. Direct impact by releasing of pro-inflammatory cytokinin leads to impact on the many organ homeostasis. The anaesthetist/intensivist must have enough knowledge of pKa/Pd and most importantly still we do not have ideal guidelines for drug dosing.

Extracorporeal Membrane Oxygenation in Acute Respiratory Failure

Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a form of mechanical life support that provides full respiratory bypass in patients with severe respiratory failure as a bridge to recovery or lung transplantation. The use of ECMO for respiratory failure and capable centers offering ECMO has expanded over the years, increasing its availability. As VV-ECMO provides an artificial mechanism for oxygenation and decarboxylation of native blood, it allows for an environment in which safer mechanical ventilatory care may be provided, allowing for treatment and resolution of underlying respiratory pathologies. Landmark clinical trials have provided a framework for better understanding patient selection criteria, resource utilization, and outcomes associated with ECMO when applied in settings of refractory respiratory failure. Maintaining close vigilance and management of complications during ECMO as well as identifying strategies post-ECMO (e.g., recovery, transplantation, etc.), are critical to successful ECMO support. In this review, we examine considerations for candidate selection for VV-ECMO, review the evidence of utilizing VV-ECMO in respiratory failure, and provide practical considerations for managing respiratory ECMO patients, including complication identification and management, as well as assessing for the ability to separate from ECMO support and the procedures for decannulation.

Use of fondaparinux in patients with heparin-induced thrombocytopenia on veno-venous extracorporeal membrane oxygenation: A three-patient case series report

Heparin-induced thrombocytopenia is a life-threatening immune-mediated complication of unfractionated heparin therapy. Fondaparinux is a therapeutic alternative, but it has limited evidence for its use in patients on extracorporeal membrane oxygenation (ECMO). We present a series of three adult patients with COVID-19 on ECMO who were diagnosed with heparin-induced thrombocytopenia after 7-12 days of unfractionated heparin treatment and were switched to fondaparinux. Fondaparinux was initiated with an intravenous loading dose of 5 mg, followed by a dose of 2.5 mg subcutaneously every 8-12 h. Dosage was adjusted according to daily measured anti-Xa concentration with a target range of 0.4-0.7 mg/L. The total duration of treatment with fondaparinux and ECMO ranged from 13 to 26 days. One major bleeding episode unrelated to fondaparinux therapy was observed, and the transfusions requirement was also low in all patients. The ECMO circuit was changed once in each patient. This series provides a deep insight into the use of fondaparinux over an extended period of time in patients on ECMO. Based on the presented data, fondaparinux can be considered a reasonable and affordable anticoagulant in patients without a high risk of bleeding.

Remdesivir Use in Low Weight, Premature, and Renally Impaired Infants With SARS-CoV-2 Infection in Sheikh Khalifa Medical City, UAE: Case Series

Remdesivir possesses in vitro inhibitory effect against severe acute respiratory syndrome coronavirus 2 and the Middle East respiratory syndrome. It works by inhibiting severe acute respiratory syndrome coronavirus 2 RNA-dependent RNA polymerase that is essential for viral replication. Remdesivir is approved by Food and Drug Administration for treating COVID-19 in hospitalized adult and pediatric patients aged 28 days and more and weighing 3 kg and more. This case series is describing two cases of low-weight, premature, and renally impaired infants where Remdesivir is used in Sheikh Khalifa Medical City pediatric intensive care unit. Upon completion of the Remdesivir course of treatment, there were no Remdesivir-related adverse outcomes noted in the two cases. Remdesivir was tolerated by both patients. However, clinical improvement and measurement of safety and efficacy will require further randomized, placebo-controlled trials.

The Future of Cardiothoracic Surgical Critical Care Medicine as a Medical Science: A Call to Action

Cardiothoracic surgical critical care medicine (CT-CCM) is a medical discipline centered on the perioperative care of diverse groups of patients. With an aging demographic and an increase in burden of chronic diseases the utilization of cardiothoracic surgical critical care units is likely to escalate in the coming decades. Given these projections, it is important to assess the state of cardiothoracic surgical intensive care, to develop goals and objectives for the future, and to identify knowledge gaps in need of scientific inquiry. This two-part review concentrates on CT-CCM as its own subspeciality of critical care and cardiothoracic surgery and provides aspirational goals for its practitioners and scientists. In part one, a list of guiding principles and a call-to-action agenda geared towards growth and promotion of CT-CCM are offered. In part two, an evaluation of selected scientific data is performed, identifying gaps in CT-CCM knowledge, and recommending direction to future scientific endeavors.

Analgosedation in Critically Ill Adults Receiving Extracorporeal Membrane Oxygenation Support

Extracorporeal membrane oxygenation (ECMO) is an increasingly utilized intervention for cardiopulmonary failure. Analgosedation during ECMO support is essential to ensure adequate pain and agitation control and ventilator synchrony, optimize ECMO support, facilitate patient assessment, and minimize adverse events. Although the principles of analgosedation are likely similar for all critically ill patients, ECMO circuitry alters medication pharmacodynamics and pharmacokinetics. The lack of clinical guidelines for analgosedation during ECMO, especially at times of medication shortage, can affect patient management. Here, we review pharmacological considerations, protocols, and special considerations for analgosedation in critically ill adults receiving ECMO support.

Pharmacokinetics, Pharmacodynamics, and Dosing Considerations of Novel β-Lactams and β-Lactam/β-Lactamase Inhibitors in Critically Ill Adult Patients: Focus on Obesity, Augmented Renal Clearance, Renal Replacement Therapies, and Extracorporeal Membrane Oxygenation

OBJECTIVE

Dose optimization of novel β-lactam antibiotics (NBLA) has become necessary given the increased prevalence of multidrug-resistant infections in intensive care units coupled with the limited number of available treatment options. Unfortunately, recommended dose regimens of NBLA based on PK/PD indices are not well-defined for critically ill patients presenting with special situations (i.e., obesity, extracorporeal membrane oxygenation (ECMO), augmented renal clearance (ARC), and renal replacement therapies (RRT)). This review aimed to discuss and summarize the available literature on the PK/PD attained indices of NBLA among critically ill patients with special circumstances.

DATA SOURCES

PubMed, MEDLINE, Scopus, Google Scholar, and Embase databases were searched for studies published between January 2011 and May 2022.

STUDY SELECTION AND DATA EXTRACTION

Articles relevant to NBLA (i.e., ceftolozane/tazobactam, ceftazidime/avibactam, cefiderocol, ceftobiprole, imipenem/relebactam, and meropenem/vaborbactam) were selected. The MeSH terms of "obesity", "augmented renal clearance", "renal replacement therapy", "extracorporeal membrane oxygenation", "pharmacokinetic", "pharmacodynamic" "critically ill", and "intensive care" were used for identification of articles. The search was limited to adult humans' studies that were published in English. A narrative synthesis of included studies was then conducted accordingly.

DATA SYNTHESIS

Available evidence surrounding the use of NBLA among critically ill patients presenting with special situations was limited by the small sample size of the included studies coupled with high heterogeneity. The PK/PD target attainments of NBLA were reported to be minimally affected by obesity and/or ECMO, whereas the effect of renal functionality (in the form of either ARC or RRT) was more substantial.

CONCLUSION

Critically ill patients presenting with special circumstances might be at risk of altered NBLA pharmacokinetics, particularly in the settings of ARC and RRT. More robust, well-designed trials are still required to define effective dose regimens able to attain therapeutic PK/PD indices of NBLA when utilized in those special scenarios, and thus aid in improving the patients' outcomes.

Dose Optimization of Meropenem in Patients on Veno-Arterial Extracorporeal Membrane Oxygenation in Critically Ill Cardiac Patients: Pharmacokinetic/Pharmacodynamic Modeling

Background: Our objective was to determine an optimal dosage regimen of meropenem in patients receiving veno-arterial extracorporeal membrane oxygenation (V-A ECMO) by developing a pharmacokinetic/pharmacodynamic (PK/PD) model. Methods: This was a prospective cohort study. Blood samples were collected during ECMO (ECMO-ON) and after ECMO (ECMO-OFF). The population pharmacokinetic model was developed using nonlinear mixed-effects modeling. A Monte Carlo simulation was used (n = 10,000) to assess the probability of target attainment. Results: Thirteen adult patients on ECMO receiving meropenem were included. Meropenem pharmacokinetics was best fitted by a two-compartment model. The final pharmacokinetic model was: CL (L/h) = 3.79 × 0.44CRRT, central volume of distribution (L) = 2.4, peripheral volume of distribution (L) = 8.56, and intercompartmental clearance (L/h) = 21.3. According to the simulation results, if more aggressive treatment is needed (100% fT > MIC target), dose increment or extended infusion is recommended. Conclusions: We established a population pharmacokinetic model for meropenem in patients receiving V-A ECMO and revealed that it is not necessary to adjust the dosage depending on V-A ECMO. Instead, more aggressive treatment is needed than that of standard treatment, and higher dosage is required without continuous renal replacement therapy (CRRT). Also, extended infusion could lead to better target attainment, and we could provide updated nomograms of the meropenem dosage regimen.

A Narrative Review of the Impact of Extracorporeal Membrane Oxygenation on the Pharmacokinetics and Pharmacodynamics of Critical Care Therapies

Objective:

Extracorporeal membrane oxygenation (ECMO) utilization is increasing on a global scale, and despite technological advances, minimal standardized approaches to pharmacotherapeutic management exist. This objective was to create a comprehensive review for medication dosing in ECMO based on the most current evidence.

Data Sources:

A literature search of PubMed was performed for all pertinent articles prior to 2022. The following search terms were utilized: ECMO, pharmacokinetics, pharmacodynamics, sedation, analgesia, antiepileptic, anticoagulation, antimicrobial, antifungal, nutrition. Retrospective cohort studies, case-control studies, case series, case reports, and ex vivo investigations were reviewed.

Study Selection and Data Extraction:

PubMed (1975 through July 2022) was the database used in the literature search. Non-English studies were excluded. Search terms included both drug class categories, specific drug names, ECMO, and pharmacokinetics.

Data Synthesis:

Medications with high protein binding (>70%) and high lipophilicity (logP > 2) are associated with circuit sequestration and the potential need for dose adjustment. Volume of distribution changes with ECMO may also impact dosing requirements of common critical care medications. Lighter sedation targets and analgosedation may help reduce sedative and analgesia requirements, whereas higher antiepileptic dosing is recommended. Vancomycin is minimally affected by the ECMO circuit and recommendations for dosing in critically ill adults are reasonable. Anticoagulation remains challenging as optimal aPTT goals have not been established.

Relevance to Patient Care and Clinical Practice:

This review describes the anticipated impacts of ECMO circuitry on sedatives, analgesics, anticoagulation, antiepileptics, antimicrobials, antifungals, and nutrition support and provides recommendations for drug therapy management.

Conclusions:

Medication pharmacokinetic/pharmacodynamic parameters should be considered when determining the potential impact of the ECMO circuit on attainment of therapeutic effect and target serum drug concentrations, and should guide therapy choices and/or dose adjustments when data are not available.

Monitoring during extracorporeal membrane oxygenation

PURPOSE OF REVIEW

Extracorporeal membrane oxygenation (ECMO) offers advanced mechanical support to patients with severe acute respiratory and/or cardiac failure. Ensuring an adequate therapeutic approach as well as prevention of ECMO-associated complications, by means of timely liberation, forms an essential part of standard ECMO care and is only achievable through continuous monitoring and evaluation. This review focus on the cardiorespiratory monitoring tools that can be used to assess and titrate adequacy of ECMO therapy; as well as methods to assess readiness to wean and/or discontinue ECMO support.

RECENT FINDINGS

Surrogates of tissue perfusion and near infrared spectroscopy are not standards of care but may provide useful information in select patients. Echocardiography allows to determine cannulas position, evaluate cardiac structures, and function, and diagnose complications. Respiratory monitoring is mandatory to achieve lung protective ventilation and identify early lung recovery, surrogate measurements of respiratory effort and ECMO derived parameters are invaluable in optimally managing ECMO patients.

SUMMARY

Novel applications of existing monitoring modalities alongside evolving technological advances enable the advanced monitoring required for safe delivery of ECMO. Liberation trials are necessary to minimize time sensitive ECMO related complications; however, these have yet to be standardized.

Machines that help machines to help patients: optimising antimicrobial dosing in patients receiving extracorporeal membrane oxygenation and renal replacement therapy using dosing software

Intensive care unit (ICU) patients with end-organ failure will require specialised machines or extracorporeal therapies to support the failing organs that would otherwise lead to death. ICU patients with severe acute kidney injury may require renal replacement therapy (RRT) to remove fluid and wastes from the body, and patients with severe cardiorespiratory failure will require extracorporeal membrane oxygenation (ECMO) to maintain adequate oxygen delivery whilst the underlying pathology is evaluated and managed. The presence of ECMO and RRT machines can further augment the existing pharmacokinetic (PK) alterations during critical illness. Significant changes in the apparent volume of distribution (V_d) and drug clearance (CL) for many important drugs have been reported during ECMO and RRT. Conventional antimicrobial dosing regimens rarely consider the impact of these changes and consequently, are unlikely to achieve effective antimicrobial exposures in critically ill patients receiving ECMO and/or RRT. Therefore, an in-depth understanding on potential PK changes during ECMO and/or RRT is required to inform antimicrobial dosing strategies in patients receiving ECMO and/or RRT. In this narrative review, we aim to discuss the potential impact of ECMO and RRT on the PK of antimicrobials and antimicrobial dosing requirements whilst receiving these extracorporeal therapies. The potential benefits of therapeutic drug monitoring (TDM) and dosing software to facilitate antimicrobial therapy for critically ill patients receiving ECMO and/or RRT are also reviewed and highlighted.

Sedation, Analgesia, and Muscle Relaxation During VV-ECMO Therapy in Patients With Severe Acute Respiratory Syndrome Coronavirus Type 2 (SARS-CoV-2): A Single-Center, Retrospective, Observational Study

Objective: The pharmacokinetics and pharmacodynamics of ECMO-supported sedative, analgesic, and muscle relaxants have changed, but there are insufficient data to determine the optimal dosing strategies for these agents. Sedation, analgesia and muscle relaxation therapy for patients with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) receiving ECMO support are more specific and have not been fully reported. This study observed and evaluated the use of sedative and analgesic drugs and muscle relaxants in SARS-CoV-2 patients treated with VV-ECMO.

Methods: This study was a single-center, retrospective and observational study. Our study includes 8 SARS-CoV-2 patients treated with VV-ECMO in an intensive care unit at Shanghai Public Health Center from February to June 2020. We collected the demographic data from these patients and the dose and course of sedation, analgesia, and muscle relaxants administered during ECMO treatment.

Results: The doses of sedative, analgesic and muscle relaxant drugs used in patients with VV-ECMO were significant. Over time, the doses of drugs that were used were increased, and the course of muscle relaxant treatment was extended.

Conclusion: Sedation, analgesia, and muscle relaxant use require individualized titration in patients with SARS-CoV-2 who have respiratory failure and who are receiving VV-ECMO.

Voriconazole pharmacokinetics in a critically ill patient during extracorporeal membrane oxygenation

The pharmacokinetics (PK) of several drugs including antimicrobials might be highly altered during extracorporeal membrane oxygenation (ECMO) therapy. We present the change of voriconazole (VRC) PK during ECMO in a critically ill patient who received intravenous VRC at a maintenance dose of 200 mg every 12 h for empirical antifungal therapy. Two PK profiles were drawn before and after the initiation of ECMO therapy. Though the trough levels (both C₀ and C₁₂) with ECMO were slightly lower than that without ECMO (12.58 and 12.84 vs. 14.02 μg/mL), the peak levels and the area under the concentration-time curve from 0 h to 6 h (AUC_0-6) were comparable (16.36 vs. 16.06 μg/mL and 90.78 vs. 91.45 μg·h/mL, respectively), indicating that VRC plasma exposure during ECMO therapy did not greatly decrease in our patient. The circuit factors including the type of membrane should be taken into account to further identify the effects of ECMO on the PK of VRC.

Extracorporeal membrane oxygenation may decrease the plasma concentration of remdesivir in a patient with severe coronavirus disease 2019

Remdesivir is an antiviral drug that results in clinical improvement after five days of treatment and accelerates recovery by 31%. No studies have discussed the pharmacokinetic analysis of remdesivir in patients with severe COVID-19 requiring extracorporeal membrane oxygenation (ECMO). A 63-year-old American man who underwent mechanical ventilation and ECMO for severe COVID-19 was administered remdesivir for ten days. The loading dosage was 200 mg at 7 PM on day 12 and 100 mg daily at 0:00 PM from day 13–21, administered within 1 h. The pharmacokinetic analysis was performed. The serum creatinine concentration was within the normal range of 0.5–0.7 mg/dL during treatment. According to the pharmacokinetic analysis, the plasma concentrations of remdesivir and GS-441524 4 h after administration (C₄) were 662 ng/mL and 58 ng/mL, respectively, and the concentrations 18 h after administration (C₁₈) were 32 ng/mL and 44 ng/mL, respectively. Therefore, the half-life of remdesivir and GS-441524 was 3.2 and 35.1 h, respectively. Monitoring the plasma concentrations of remdesivir and GS-441524 in patients undergoing ECMO may be necessary.

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A COVID-19 patient undergoing ECMO was administered remdesivir.

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The loading dosage was 200 mg at 7:00 PM on day 12.

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From days 13–21, it was 100 mg daily at 0:00 PM administered within 1 h.

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The half-lives of remdesivir and GS-441524 were 3.2 and 35.1 h, respectively.

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Plasma concentrations of remdesivir and GS-441524 must be monitored during ECMO.

Opioid and sedative requirements in extracorporeal membrane oxygenation patients on hydromorphone versus fentanyl

BACKGROUND

The extracorporeal membrane oxygenation (ECMO) circuit causes pharmacokinetic alterations of medications which impact drug selection and dosing. Although hydromorphone has a favorable pharmacokinetic profile, it is unclear whether hydromorphone provides better patient-centered benefits compared to fentanyl. The objective of this study is to compare opioid and sedative requirements in ECMO patients started on a fentanyl- versus hydromorphone-based analgesia regimen.

METHODS

This was a non-interventional retrospective cohort study. It was conducted at a single center in the cardiovascular intensive care units and cardiac intensive care units. We included venovenous (VV) or venoarterial ECMO patients. Patients who were started on a fentanyl continuous infusion within 24 h of cannulation were compared to patients started on a hydromorphone continuous infusion.

RESULTS

A linear mixed effects model was performed to compare doses of opioid, sedative, and propofol between groups over time. We included 28 hydromorphone patients and 53 fentanyl patients, with 85% on VV ECMO. There were no differences between hydromorphone and fentanyl groups in opioid or sedative (including propofol and benzodiazepine) doses for any ECMO day (p value for interaction .63 and .83, respectively). Propofol doses alone, however, were significantly higher in the fentanyl group on ECMO days three, four, and five.

CONCLUSIONS

There appear to be no major differences in opioid or sedative requirements whether ECMO patients are initiated on a hydromorphone- or fentanyl-based regimen.

Population Pharmacokinetics of Meropenem in Critically Ill Korean Patients and Effects of Extracorporeal Membrane Oxygenation

Limited studies have investigated population pharmacokinetic (PK) models and optimal dosage regimens of meropenem for critically ill adult patients using the probability of target attainment, including patients receiving extracorporeal membrane oxygenation (ECMO). A population PK analysis was conducted using non-linear mixed-effect modeling. Monte Carlo simulation was used to determine for how long the free drug concentration was above the minimum inhibitory concentration (MIC) at steady state conditions in patients with various degrees of renal function. Meropenem PK in critically ill patients was described using a two-compartment model, in which glomerular filtration rate was identified as a covariate for clearance. ECMO did not affect meropenem PK. The simulation results showed that the current meropenem dosing regimen would be sufficient for attaining 40%fT_>MIC for Pseudomonas aeruginosa at MIC ≤ 4 mg/L. Prolonged infusion over 3 h or a high-dosage regimen of 2 g/8 h was needed for MIC > 2 mg/L or in patients with augmented renal clearance, for a target of 100%fT_>MIC or 100%fT_>4XMIC. Our study suggests that clinicians should consider prolonged infusion or a high-dosage regimen of meropenem, particularly when treating critically ill patients with augmented renal clearance or those infected with pathogens with decreased in vitro susceptibility, regardless of ECMO support.