[HME filter versus patient-related replacement of tubes from the ventilation circuit for anaesthesia: a cost-benefit analysis]. / HME-Filter versus patientenbezogener Wechsel der Beatmungsschlauchsysteme von Narkosegeräten: Eine Kosten-Nutzen-Analyse.

Procedure-related costs were calculated for an operating theatre with 10 operating rooms. The variable parameter was the different hygiene regimens for the preparation of the anaesthesia circuit. In April 2003 a change was made for the whole anaesthesia area. Either change of the anaesthesia tube system after every patient or the use of a hydrophobic HME-F (heat and moisture exchange filter) with daily or weekly change of the anaesthesia tube system were calculated. All costs were ascertained on real findings and typical procedures. Data according to safety and hygienic value were discussed and supplemented by our own findings about perioperative pneumonia. The additional costs for the HME-F are covered by the savings for CO(2) lines and the reduction of reprocessing expenses and overall material costs were reduced. The operational work on anaesthesia machines decreased considerably. Combined cost types revealed savings up to 9,72 EUR for a single anaesthesia procedure. Filtration of the respiratory gases for particles, bacteria, viruses and airway climatisation is an additional positive effect of HME-F use. Incidence of postoperative pneumonia on intensive care units was monitored by KISS (German hospital infection surveillance system) and the change to the HME-F regimen did not indicate a higher risk of infection. By the implementation of a weekly change of the anaesthesia tube system using HME filters a hygienic management for anaesthesia circuit reprocessing was found which could mobilize considerable resources.

[The effects of active and passive humidification on ventilation-associated nosocomial pneumonia]. / Einfluss von aktiver und passiver Befeuchtung auf die beatmungsassoziierte nosokomiale Pneumonie.

STUDY OBJECTIVE: Airway humidification of ventilated patients in an intensive care unit may be established by heated humidifying systems (active) or by the means of a (passive) heat and moisture exchange filter (HMEF). There is a controversial discussion about the influence of the type of humidification on the rate of ventilator-associated pneumonia (VAP). Among 3,585 patients both methods were tested over a period of 21 months in an open, non-randomized cohort study. The aim of the investigation was to compare the incidence of VAP caused by a change of humidification strategy. METHOD: All patients in a 16-bed surgical intensive care unit who required mechanical ventilation, were included. In the first period (period AB) 1,887 cases were handled with a heated humidifier. During the second period (period PB) 1,698 patients were treated using a HMEF. Infection control was established according to the national Infection Surveillance Program (KISS) based on the CDC criteria for VAP. RESULTS: During the period of 42 months, 99 cases of VAP were reported. The incidence for VAP was found to be 13.5 (AB) and 9.6 (PB) per 1,000 ventilator days, a rate of 32.3 and 22.4 VAP per 1,000 patients, respectively. The rate of VAP among the groups ( p=0.068) and the incidence of VAP per 1,000 ventilator days ( p=0.089) only just failed to reach a significant level, but in the group of patients requiring mechanical ventilation for more than 2 days, the difference did reach statistical significance ( p=0.012). CONCLUSION: Our results showed that the rate of VAP could be significantly reduced by changing the strategy from active to passive humidification devices, especially concerning patients requiring long-term respirator therapy. A more physiological humidification and a reduced number of airway manipulations are discussed as a possible explanation.