Meropenem Dosing in Central ECMO
For patients on central (veno-arterial) ECMO, administer meropenem 1 gram IV every 8 hours as standard dosing, with consideration for extended infusion (over 3 hours) or dose escalation to 2 grams every 8 hours if treating resistant organisms (MIC ≥8 mg/L) or if the patient has preserved/augmented renal function. 1, 2, 3
Standard Dosing Approach
The baseline regimen is 1 gram IV every 8 hours for most patients on V-A ECMO, which maintains adequate concentrations for typical pathogens 1, 2, 3
ECMO patients demonstrate decreased meropenem clearance (7.9 ± 5.9 L/h) compared to non-ECMO critically ill patients (11.7 ± 6.5 L/h), though this difference is not statistically significant 2
The volume of distribution is numerically higher in ECMO patients (0.45 ± 0.17 L/kg versus 0.41 ± 0.13 L/kg), but the decreased clearance compensates for this increase 2
When to Escalate Dosing
Increase to 2 grams IV every 8 hours in the following scenarios:
Patients with preserved or augmented creatinine clearance (not receiving continuous renal replacement therapy), as these patients have significantly higher meropenem clearance 2, 3, 4
When targeting more aggressive pharmacodynamic goals (100% fT>MIC or 100% fT>4×MIC) rather than the standard 40% fT>MIC 4
Infections with pathogens having MIC ≥8 mg/L, where standard dosing may be insufficient 1, 4
Extended Infusion Strategy
Administer meropenem as a 3-hour extended infusion when treating resistant organisms or when MIC ≥8 mg/L 1, 3
Extended infusion significantly improves probability of target attainment for aggressive PK/PD targets (100% fT>MIC) 3, 4
For standard pathogens with MIC ≤2 mg/L, traditional 5-minute bolus administration is acceptable 2, 4
Critical Considerations for ECMO Patients
Renal function is the primary determinant of meropenem dosing, not ECMO itself:
Patients on concurrent CRRT: Standard 1 gram every 8 hours is typically sufficient, as CRRT significantly reduces clearance (CL = 3.79 × 0.44 when CRRT is present) 3
Patients with preserved renal function on ECMO: May require higher doses (2 grams every 8 hours) due to augmented renal clearance commonly seen in critically ill cardiac patients 2, 3, 4
Meropenem clearance correlates directly with creatinine clearance in ECMO patients, with variability in clearance primarily explained by renal function rather than ECMO circuit effects 2, 3
Monitoring and Target Attainment
Target trough concentrations >2 mg/L are routinely achieved with standard dosing (1 gram every 8 hours) in all ECMO patients 2
For less susceptible organisms requiring trough >8 mg/L, only 8 of 11 patients achieved this target with standard dosing, and 5 of those 8 were receiving CRRT 2
The 40% fT>MIC target is reliably achieved with 1 gram every 8 hours for P. aeruginosa (MIC 8 mg/L) in ECMO patients 4
Common Pitfalls to Avoid
Do not automatically reduce meropenem doses simply because a patient is on ECMO—the circuit itself does not significantly alter pharmacokinetics 2, 3
Avoid underdosing in patients with preserved renal function, as augmented renal clearance is common in critically ill cardiac patients on V-A ECMO 3, 4
Do not use continuous infusion as first-line unless treating highly resistant organisms (MIC ≥8 mg/L) or targeting aggressive PK/PD goals, as standard intermittent dosing is effective for most infections 4
Remember that meropenem is unstable during prolonged continuous infusion, making extended intermittent infusion (3 hours) preferable to true continuous infusion 1