Background
The majority of patients admitted to Intensive Care Units (ICUs) require an artificial airway and mechanical ventilation (MV). An important aspect of airway management in these patients is to remove secretions by endotracheal suctioning. Multiple use closed suction systems (CSS) are increasingly replacing single-use open suction system (OSS) to perform this invasive procedure. However, recommendations for the routine use of CSS remained controversial because of inconclusive study results.

Objective
The objective was to determine effectiveness of closed and open suction systems with respect to (1) reducing the incidence of cross-transmission and acquisition with Gram-negative bacteria in intensive care units, (2) reducing changes in cardiorespiratory variables, and (3) costs. Furthermore, based upon the microbiological results in this study, we determined (4) risk factors for acquiring respiratory tract colonization with Gram-negative bacteria, (5) acquisition of antibiotic resistance, and (5) the population structure of P. aeruginosa isolated from intensive care patients as compared with isolates from cystic fibrosis patients.

Results
In a prospective crossover design with fixed periods in which either of both systems was used for all patients in the intensive care unit, 37% of the patients acquired respiratory tract colonization with at least one of the selected Gram-negative bacteria in each of the study periods. Overall acquisition rates were 35.5 and 32.5 per 1000 patient days at risk during CSS and OSS, respectively. Cross-transmission rates with Pseudomonas aeruginosa, Acinetobacter species and Enterobacter species were low: 5.7 and 4.5 per 1000 patient days at risk with any of these pathogens during CSS and OSS, respectively.
The physiological consequences of CSS and OSS were investigated in an observational study nested within the crossover trial. Changes in heart rate and mean arterial pressure appeared minor and were comparable when using either CSS or OSS. Only changes in peripheral oxygen saturation appeared higher after using OSS as compared to CSS, but differences were very small (98.2% and 97.5%) and therefore clinically not relevant.
In the UMC Utrecht, the price of using OSS was € 5 and of CSS €11,20 per patient per day (price level the Netherlands, 2009), and using OSS instead of CSS would save over €60,000 per year.

Conclusion
Based upon the results, both CSS and OSS can be considered equally safe in mechanically ventilated ICU patients. We could not demonstrate a difference in overall cross transmission, nor in overall acquisition of respiratory tract colonization. Furthermore, no clinically relevant differences in cardiorespiratory variables were found. The implications of the results for clinical practice are rather straightforward: the choice of the ES system to be used can be based on costs and personal preference.