Guideline for antimicrobial prophylaxis for Paediatric Cardiac Surgery

1. Summary table of routine recommendations
2. Background information
3. Special antimicrobial prophylaxis recommendations

1. Summary table of routine recommendations

** if there is evidence of acute kidney injury i.e. Cr rising, reduced urinary output, then check a random Gentamicin level 24 hours post dose and if the level is below 1mg/L then give a 2nd dose of 2.5mg/kg (max. 80mg). If the level is above 1mg/L then repeat level in 12 hours.

*MRSA risk = previous MRSA infection or known colonisation

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2. Background information

Antimicrobial prophylaxis in cardiothoracic surgery has been a standard practice for some years. Post-operative mediastinitis can be a devastating infection with a high mortality leading to prolonged hospitalisation, additional surgery and a significant burden on clinical resources.

Children undergoing cardiac surgery may be at even higher risk of surgical site infections (SSIs) than their adult counterparts because of an immature immune system, longer duration of operation, practice of delayed sternal closure following complex reconstructions and quite often, prolonged central venous access for parenteral nutrition. Currently, there are no randomized trials in children undergoing cardiac surgery. Conclusions, therefore, have been extrapolated from trials conducted in adults.

Antibiotic prophylaxis is only one of the preventative measures to reduce the incidence of SSI, aseptic surgical technique, pre-operative screening and decolonisation, temperature and blood glucose control and post-operative wound management should be vital part of the local care bundles.

A review of antimicrobial prophylaxis in Leeds has been prompted by an increasing number of complex surgeries and growing burden of Meticillin Sensitive Staphylococcus aureus (MSSA) wound infections/bacteremia and MSSA outbreak in 2012.

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3. Special antimicrobial prophylaxis recommendations

CHOICE AND DURATION OF ANTIBIOTIC THERAPY

The antimicrobial choice needs to be guided by historical and institutional knowledge of common pathogens causing infections following the specific procedure and a recent look back exercise in Leeds suggested Staphyloccus aureus as the most common organism causing cardiac SSIs in children. This has been the basis of changing the antimicrobial prophylaxis to Flucloxacillin   and Gentamicin. A single dose of Gentamicin has been chosen to provide synergism for MSSA and additional cover for MRSA as MRSA SSIs have continued to occur in those children who were not identified as at risk of MRSA pre-procedure. Giving a 5mg/kg dose over 10minutes is likely to achieve a transient high peak concentration as with Once daily(OD) Gentamicin and studies using OD Gentamicin have shown no greater incidence of ototoxicity or nephrotoxicity compared with traditional thrice daily dosing (3). A benchmarking exercise in March 2012 reviewing antibiotic prophylaxis at other children cardiac centres in UK supported such prophylactic regime and notably, no concerns regarding renal impairment or Gentamicin toxicity have been reported.

Vancomycin  and Teicoplanin  are no more effective than beta-lactam agents like Flucloxacillin   for the prevention of surgical site infections after cardiac surgery as shown by a recent meta-analysis. In subanalyses, beta-lactams were superior to glycopeptides for prevention of chest SSIs (RR, 1.47; 95% CI, 1.11–1.95) and approached superiority for prevention of deep-chest SSIs (RR, 1.33; 95% CI, 0.91–1.94) and SSIs caused by gram-positive bacteria (RR, 1.36; 95% CI, 0.98–1.91). However, glycopeptides were found to be to be superior to beta lactam agents for preventing SSIs caused by MRSA (4) supporting an alternative regime for patients at high risk of MRSA infection (2). A glycopeptide may also be used effectively in the setting of allergy to Penicillin or Cephalosporin.

MRSA carriage has been identified as a high risk factor for SSIs in patients undergoing cardiac surgery and such patients should have decolonisation therapy with intranasal Mupirocin prior to surgery (1). Naspetin may be used as an alternative to Mupirocin if MRSA strain found to be Mupirocin resistant. If MRSA screening results are not available at the time of surgery, these patients should have decolonisation therapy, as per Leeds Teaching Hospitals Trust guidelines.

There is a considerable body of evidence supporting the need for the timely administration of preoperative antibiotics, which means administration within 1 hour of the skin incision (Evidence level A). A single dose of antibiotic with long half life is adequate to achieve activity throughout the procedure; however, an additional intra-operative dose is required for cardiac surgery lasting more than 4 hours (1).

Sternal Closure
Open chest management and delayed sternal closure after cardiac surgery is a therapeutic option in the treatment of the severely impaired heart in paediatric cardiac surgery, however, the prolonged sternal closure time is associated with increased rate of postoperative infection rate and therefore an attempt should be made to close the skin in those haemodynamically unstable patients where cardiac compression by sternal closure is not tolerated. These children should be continued on antiseptic skin washes till the sternum can be closed (Octenisan or Chlorhexidine washes as guided by the age of the child). The duration of antibiotic prophylaxis should not exceed 48hours and should not be dependent on indwelling catheters or drains of any type as it does not offer any additional protection against infectious complications.

ECMO
Patients on extracorporeal life support should receive the same antibiotic prophylaxis; however, there should be a low threshold for broadening coverage as and when required.

Summary & Conclusions

1. Prophylactic antibiotics should be routinely administered to paediatric patients undergoing cardiac surgery and interventional cardiac catheter placements. Effective prophylaxis depends on an adequate serum antibiotic concentration at the time of the skin incision, as well as during and shortly after the operation. Proper timing of antibiotic administration therefore is essential. The recommended regimen for cardiac surgery is Flucloxacillin   25mg/kg/dose with Gentamicin 5mg/kg/dose intravenously at induction of anaesthesia and 6 hourly Flucloxacillin   25mg/kg/dose for 3 subsequent doses (prophylaxis should not exceed 24hours). Whilst the recommended regimen for interventional cardiac catheter placements is Teicoplanin  10mg/kg/dose at induction of anaesthesia (as these patients are not currently routinely screened for MRSA, so their status is unknown). Please refer to table 1 for prophylaxis details.
2. Teicoplanin  10mg/kg/dose should replace the Flucloxacillin as antimicrobial prophylaxis for patients who have been screened as MRSA positive or identified as high risk for MRSA (if screening results not available) or have a true penicillin allergy. Please refer to table 1 for prophylaxis details and dosing regime.
3. The duration of antibiotic prophylaxis should not be dependent on catheters, lines, nor drains of any type.
4. Microbiology opinion should be sought for individual patients with complex microbiological problems, patients in renal failure or those who are already receiving antimicrobials for chest infections, necrotising enterocolitis, endocarditis etc