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Three Part Question

In [patients undergoing cardiac surgery] does the [topical application of Vancomycin to the sternotomy wound] reduce [incidence of mediastinitis]?

Clinical Scenario

While closing a 59 year old lady after elective mitral valve replacement, the theatre nurse hands you 500mg of vancomycin powder to apply to the sternotomy wound prior to closure. You have just completed a BET relating to resistant bacteria in surgical patients and you question whether there is any benefit to this method in addition to intravenous antibiotics.

Search Strategy

Medline 1966-07/02 using the OVID interface.
[cardiac surgical procedures.mp OR Thoracic surgery.mp OR Coronary artery Bypass.mp OR Cardiopulmonary Bypass.mp OR Thoracic Surgical Procedures.mp OR Cardiovascular Surgical Procedures.mp] AND [Vancomycin.mp] OR [(mediastinitis.mp OR "sternal wound".mp OR "sternal infection".mp) AND Vancomycin.mp]

Search Outcome

Out of 98 papers only one was found to be relevant. This paper is shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Vander Salm et al, 1989, USA	416 patients undergoing cardiac operations. All patients received prophylactic iv Cefazolin for 36 hrs (or iv vancomycin if allergies present – 42). 223 patients had 1g of topical vancomycin applied to the sternal edges with a haemostatic paste of thrombin and powdered absorbable gelatin. 193 patients had the haemostatic paste alone. All patients also had 2 days of prophylactic intravenous antibiotics.	PRCT. Single blinded	Sternal infection (superficial wound infections not included).	Vancomycin group:1 out of 223 sternal infections(0.45%). Control group :7 out of 193 sternal infections(3.6%). P=0.013	Flawed randomisation (odd/even hospital numbers)
			Other factors that may cause sternal infection	Operative time was also correlated with sternal infection (P=0.014)

Comment(s)

Only 1 paper was found that supported the use of Topical Vancomycin in cardiac surgery, and this paper reports a reduction of 6 sternal wound infections (Number Needed to Treat is 1/ (0.036-0.0045) = 32). Also found in the search was a paper by Massias et al 1992 (2) That took 10 sternal biopsies intraoperatively after 48hrs of preoperative intravenous vancomycin prophylaxis and they found vancomycin concentrations of 9+/-3mcg/l which is well in the therapeutic range. A search was therefore also done for studies that looked at the addition of Vancomycin i.v. to standard prophylaxis. No studies were found, only studies comparing vancomycin as a replacement to standard prophylaxis. Therefore it is unknown whether giving vancomycin i.v. instead of topically would be equally effective.

Clinical Bottom Line

Topical Vancomycin applied to the sternal edges with haemostatic paste is effective in reducing the incidence of sternal infection (NNT 32).

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Vander Salm TJ, Okike ON, Pasque MK, Pezzella AT, Lew R, Traina V et al. Reduction of sternal infection by application of topical vancomycin. Journal of Thoracic & Cardiovascular Surgery 1989;98(4):618-22.
2. Massias L, Dubois C, de Lentdecker P, Brodaty O, Fischler M, Farinotti R. Penetration of vancomycin in uninfected sternal bone. Antimicrobial Agents & Chemotherapy 1992;36(11):2539-41.