Bacterial contamination of suction catheter tips during aortic valve replacement surgery: a prospective observational cohort study

Background

Bacterial mediastinitis is a severe complication after open heart surgery. The infection causes prolonged hospitalization and an increased mortality risk. Observations from orthopaedic surgery showed that the suction catheter used during surgery is commonly contaminated with bacteria. The aim of this study was to describe the prevalence of suction catheter contamination in cardiac surgery and to study if suction time influences the contamination risk.

Methods

Fifty suction catheter tips were collected during 25 aortic valve replacement operations. The suction tip was exchanged once during the operation (after aortotomy closure). The tips were subjected to bacterial contamination analysis.

Results

In 20 of the 25 investigated cases (80%), bacterial contamination was detected on one or both tips. The tip used during the beginning of the operation showed bacterial contamination in 13/25 cases (52%) and the second tip in 12/25 (48%). In 5/25 cases (20%) both tips were contaminated. There was no association between bacterial contamination and suction time. Coagulase-negative staphylococcus was the most commonly detected microorganism.

Conclusions

The suction device should be considered as a potential source of bacterial contamination in cardiac surgery. The results suggest that the suction catheter should be replaced before key moments like valve implantation and sternal closure.

Triclosan-coated sutures reduce surgical site infection after open vein harvesting in coronary artery bypass grafting patients: a randomized controlled trial

OBJECTIVES

The incidence of surgical site infection (SSI) after open vein harvesting in coronary artery bypass grafting (CABG) patients ranges in different studies between 2 and 20%. Triclosan is an antibacterial substance that reduces the growth of bacteria by inhibiting fatty acid synthesis. We hypothesized that wound closure with triclosan-coated sutures would reduce SSI after open vein harvesting.

METHODS

An investigator-initiated prospective randomized double-blind single-centre study was performed with 374 patients, randomized to subcutaneous and intracutaneous leg-wound closure with either triclosan-coated sutures (Vicryl Plus and Monocryl Plus, Ethicon, Somerville, NJ, USA) (n = 184) or identical sutures without triclosan (n = 190) from the same manufacturer. All patients were followed up after 30 days (clinical visit) and 60 days (telephone interview). Primary endpoint was SSI within 60 days after surgery according to the definition of Center for Disease Control. Predefined secondary endpoints included culture-proven and antibiotic-treated SSI.

RESULTS

The primary endpoint occurred in 23 patients (12.5%) with triclosan-coated sutures and in 38 patients (20.0%) in the group without triclosan (P = 0.0497, risk ratio 0.63, (95% confidence interval 0.39-1.00). Corresponding figures for culture-proven infections were 7.6 vs 12.1%, (P = 0.15), and for antibiotic-treated infections, 10.9 vs 18.4%, (P = 0.039). Staphylococcus aureus and coagulase-negative staphylococci were the most common pathogens in both groups. Insulin-treated diabetes and vein-harvesting time were associated with SSI after vein harvesting.

CONCLUSIONS

Leg-wound closure with triclosan-coated sutures in CABG patients reduces SSIs after open vein harvesting. (ClinicalTrials.gov number NCT01212315).

Sampling conditions influence multiple electrode platelet aggregometry in cardiac surgery patients

OBJECTIVES

To investigate the importance of blood sampling conditions for multiple electrode platelet aggregometry (MEA) in cardiac surgery patients.

DESIGN

Eighty-one patients undergoing first time CABG surgery were included in three prospective, observational studies. MEA was used to analyze platelet aggregability after addition of adenosine-diphosphate (ADP) or thrombin activating peptide 6 (TRAP). In substudy 1, hirudin and citrate tubes were compared. In substudy 2, samples from peripheral vein, central venous catheter, and radial artery were compared and in substudy 3, the effect of surgery was investigated by analyzing pre- and postoperative samples.

RESULTS

Platelet aggregability values were 30% higher in hirudin tubes than in citrate tubes. There was a significant correlation between hirudin and citrate tubes in TRAP-induced aggregability (r = 0.84, p < 0.001) but not in ADP-induced aggregability (r = 0.25, p = 0.13). The blood sampling site did not influence platelet aggregability. Surgery reduced ADP-induced aggregability by 31% (p < 0.001) and TRAP-induced aggregability by 30% (p < 0.001) with large intraindividual variations.

CONCLUSIONS

MEA results in cardiac surgery patients should not be compared between samples collected in test tubes with different anticoagulants. The choice of blood sampling site does not affect the results. The operation in itself reduces markedly mean platelet aggregability.