Amiodarone Extraction by the Extracorporeal Membrane Oxygenation Circuit

Meropenem extraction by ex vivo extracorporeal life support circuits

BACKGROUND

Meropenem is a broad-spectrum carbapenem-type antibiotic commonly used to treat critically ill patients infected with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. As many of these patients require extracorporeal membrane oxygenation (ECMO) and/or continuous renal replacement therapy (CRRT), it is important to understand how these extracorporeal life support circuits impact meropenem pharmacokinetics. Based on the physicochemical properties of meropenem, it is expected that ECMO circuits will minimally extract meropenem, while CRRT circuits will rapidly clear meropenem. The present study seeks to determine the extraction of meropenem from ex vivo ECMO and CRRT circuits and elucidate the contribution of different ECMO circuit components to extraction.

METHODS

Standard doses of meropenem were administered to three different configurations (n = 3 per configuration) of blood-primed ex vivo ECMO circuits and serial sampling was conducted over 24 h. Similarly, standard doses of meropenem were administered to CRRT circuits (n = 4) and serial sampling was conducted over 4 h. Meropenem was administered to separate tubes primed with circuit blood to serve as controls to account for drug degradation. Meropenem concentrations were quantified, and percent recovery was calculated for each sample.

RESULTS

Meropenem was cleared at a similar rate in ECMO circuits of different configurations (n = 3) and controls (n = 6), with mean (standard deviation) recovery at 24 h of 15.6% (12.9) in Complete circuits, 37.9% (8.3) in Oxygenator circuits, 47.1% (8.2) in Pump circuits, and 20.6% (20.6) in controls. In CRRT circuits (n = 4) meropenem was cleared rapidly compared with controls (n = 6) with a mean recovery at 2 h of 2.36% (1.44) in circuits and 93.0% (7.1) in controls.

CONCLUSION

Meropenem is rapidly cleared by hemodiafiltration during CRRT. There is minimal adsorption of meropenem to ECMO circuit components; however, meropenem undergoes significant degradation and/or plasma metabolism at physiological conditions. These ex vivo findings will advise pharmacists and physicians on the appropriate dosing of meropenem.

Protective Role of Amiodarone on Reperfusion Arrhythmia in Patients of Acute Myocardial Infarction with Percutaneous Coronary Intervention Treatment

With the development and popularity of percutaneous coronary intervention (PCI), ischemia-reperfusion injury (IRI) has attracted more and more clinical attention. Reperfusion arrhythmia (RA), one of the common manifestations during and after PCI, can affect the postoperative cardiac function of patients with acute myocardial infarction (AMI). Therefore, effective intervention on RA has important clinical significance. This study observed the effect of amiodarone on reperfusion arrhythmia (RA) after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) and explored its possible mechanism. The results showed that amiodarone had good clinical efficacy in the prevention of RA in patients with AMI after PCI, and it could reduce the levels of serum IL-6, hs-CRP, CK-MB, and cTnI in patients and reduce the damage caused by reperfusion, thereby reducing the occurrence of RA.

Impaired Pharmacokinetics of Amiodarone under Veno-Venous Extracorporeal Membrane Oxygenation: From Bench to Bedside

BACKGROUND

Adjusting drug therapy under veno-venous extracorporeal membrane oxygenation (VV ECMO) is challenging. Although impaired pharmacokinetics (PK) under VV ECMO have been reported for sedative drugs and antibiotics, data about amiodarone are lacking. We evaluated the pharmacokinetics of amiodarone under VV ECMO both in vitro and in vivo.

METHODS

In vitro: Amiodarone concentration decays were compared between closed-loop ECMO and control stirring containers over a 24 h period. In vivo: Potassium-induced cardiac arrest in 10 pigs with ARDS, assigned to either control or VV ECMO groups, was treated with 300 mg amiodarone injection under continuous cardiopulmonary resuscitation. Pharmacokinetic parameters Cmax, Tmax AUC and F were determined from both direct amiodarone plasma concentrations observation and non-linear mixed effects modeling estimation.

RESULTS

An in vitro study revealed a rapid and significant decrease in amiodarone concentrations in the closed-loop ECMO circuitry whereas it remained stable in control experiment. In vivo study revealed a 32% decrease in the AUC and a significant 42% drop of Cmax in the VV ECMO group as compared to controls. No difference in Tmax was observed. VV ECMO significantly modified both central distribution volume and amiodarone clearance. Monte Carlo simulations predicted that a 600 mg bolus of amiodarone under VV ECMO would achieve the amiodarone bioavailability observed in the control group.

CONCLUSIONS

This is the first study to report decreased amiodarone bioavailability under VV ECMO. Higher doses of amiodarone should be considered for effective amiodarone exposure under VV ECMO.