Mediastinitis following cardiac surgery

For patients with mediastinitis following cardiac surgery who have sepsis or septic shock, start antibiotic therapy within 1 hour of presentation to medical care or, for ward-based patients, development of sepsis or septic shock. Antibiotics should be administered immediately after blood samples are taken for culture. For nonantibiotic management of sepsis or septic shock, see Resuscitation of patients with sepsis or septic shock.

For hospital-acquired mediastinitis following cardiac surgery in patients who had a median sternotomy, use the results of culture and susceptibility testing to guide initial therapy.

In adults and children, if microbiological results are not available, antibiotic choice should be guided by local protocols, or clinical microbiology or infectious diseases advice. In the absence of local protocols or microbiological results, the following regimens can be used in adults; add-on therapy for methicillin-resistant Staphylococcus aureus (MRSA) may be required (see regimen below).

In adults with mediastinitis following cardiac surgery, useAbdul-Aziz, 2024Dulhunty, 2024:

piperacillin+tazobactam intravenously. For dosage adjustment in adults with kidney impairment, see piperacillin+tazobactam dosage adjustment piperacillin + tazobactam piperacillin+tazobactam piperacillin+tazobactam

patients without septic shock and not requiring intensive care support: 4+0.5 g 6-hourly1

patients with septic shock or requiring intensive care support: 4+0.5 g administered as a loading dose over 30 minutes. After 3 hours, start a continuous infusion of 16+2 g administered over 24 hours23.

For adults who have had a nonsevere (immediate or delayed) hypersensitivity reaction to a penicillin, use:

cefepime 2 g intravenously, 8-hourly. For dosage adjustment in adults with kidney impairment, see cefepime dosage adjustment. cefepime cefepime cefepime

For adults who have had severe immediate4 hypersensitivity reaction to a penicillin, cefepime (at the dosage above) can be considered if a beta-lactam antibiotic is strongly preferred (for considerations, see Severe immediate hypersensitivity: Implications of cross-reactivity between penicillins and cephalosporins).

For adults who have had a severe immediate4 hypersensitivity reaction to a penicillin in whom cefepime is not used, or for adults who have had a severe delayed5 hypersensitivity reaction to a penicillin, meropenem may be suitable6. UseAbdul-Aziz, 2024Dulhunty, 2024:

meropenem intravenously. For dosage adjustment in adults with kidney impairment, see meropenem dosage adjustment meropenem meropenem meropenem

patients without septic shock and not requiring intensive care support: 1 g 8-hourly

patients with septic shock or requiring intensive care support: 2 g administered as a loading dose over 30 minutes. After 4 hours, administer 2 g 8-hourly, as consecutive 8-hour infusions78.

For adults at increased risk of methicillin-resistant Staphylococcus aureus (MRSA), known to be colonised with MRSA, or with sepsis or septic shock, add to all of the above regimensKornberger, 2016Samura, 2022Shariati, 2020:

vancomycin intravenously; for initial dosing, see Vancomycin dosing in adults. Loading doses are recommended for critically ill adults. vancomycin vancomycin vancomycin

Modification and duration of therapy: Seek expert advice for ongoing management, timing of switch to oral therapy and duration of therapy. If Pseudomonas aeruginosa is not subsequently identified by culture, ongoing antipseudomonal therapy is not required. Switch to a narrower-spectrum empirical regimen or modify therapy based on the results of culture and susceptibility testing. For severe mediastinitis (eg life-threatening or complicated infection), treatment for 4 to 6 weeks (intravenous + oral) may be requiredMcMullan, 2016.

More fastidious or opportunistic organisms may also be implicated (eg Mycobacterium chimaera, Mycoplasma species), particularly in immunocompromised patientsPastene, 2020. For culture-negative mediastinitis, seek expert advice for diagnosis and management.

1 Administration of piperacillin+tazobactam over 3 hours may be preferred to ensure adequate drug exposure for Pseudomonas aeruginosa. For more information, see Practical information on using beta lactams: penicillins.Return
2 For patients with septic shock or requiring intensive care support, administering the total daily dose of piperacillin+tazobactam over 24 hours is preferred to ensure adequate drug exposure. If this is not possible (eg the patient is receiving other drugs via the same line), administer the standard dose (4+0.5 g intravenously, 6-hourly) as an extended infusion over 3 hours. If a 3-hour infusion is not possible, administer over 30 minutes. For more information, see Practical information on using beta lactams: penicillins.Return
3 The modified dosage of piperacillin+tazobactam for patients with septic shock or those requiring intensive care support is recommended to ensure adequate drug exposure, because pharmacokinetics may be altered in patients with critical illness (eg because of enhanced kidney clearance or changes in volume of distribution). Once the critical illness has resolved, consider switching to the standard dosage.Return
4 Severe immediate hypersensitivity reactions include anaphylaxis, compromised airway, airway angioedema, hypotension and collapse.Return
5 Severe delayed hypersensitivity reactions include cutaneous adverse drug reactions (eg drug rash with eosinophilia and systemic symptoms [DRESS], Stevens–Johnson syndrome/toxic epidermal necrolysis [SJS/TEN], severe blistering or desquamative rash), and significant internal organ involvement (eg acute interstitial nephritis).Return
6 In patients with penicillin hypersensitivity, the rate of immune-mediated cross-reactivity with carbapenems is approximately 1%; therefore, meropenem can be considered in supervised settings. However, in patients with a history of a severe cutaneous adverse reaction (eg drug rash with eosinophilia and systemic symptoms [DRESS], Stevens–Johnson syndrome/toxic epidermal necrolysis [SJS/TEN]), consider meropenem only in a critical situation when there are limited treatment options.Return
7 For patients with septic shock or requiring intensive care support, administering the total daily dose of meropenem over 24 hours (as 3 consecutive 8-hourly infusions) is preferred to ensure adequate drug exposure. If this is not possible (eg the patient is receiving other drugs via the same line), administer the dose (2 g 8-hourly) as an extended infusion over 3 hours. If a 3-hour infusion is not possible, administer over 30 minutes. For more information, see Practical information on using beta lactams: carbapenems.Return
8 The modified dosage of meropenem for patients with septic shock or those requiring intensive care support is recommended to ensure adequate drug exposure, because pharmacokinetics may be altered in patients with critical illness (eg because of enhanced kidney clearance or changes in volume of distribution). Once the critical illness has resolved, consider administering the dose over 3 hours. If infection with Pseudomonas aeruginosa has been excluded, consider switching to the standard dosage.Return