***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective : To determine whether use of a single heat and moisture exchanger ( HME ) for ≤120 hrs affects efficiency , resistance , level of bacterial colonization , frequency rate of nosocomial pneumonia , and cost compared with changing the HME every 24 hrs . Design : Prospect i ve , controlled , r and omized , unblinded study . Setting : Surgical intensive care unit at a university teaching hospital . Patients : A total of 220 consecutive patients requiring mechanical ventilation for > 48 hrs . Interventions : Patients were r and omized to one of three groups : a ) hygroscopic HME ( Aqua+ ) changed every 24 hrs ( HHME‐24 ) ; b ) hydrophobic HME ( Duration HME ) changed every 120 hrs ( HME‐120 ) ; and c ) hygroscopic HME ( Aqua+ ) changed every 120 hrs ( HHME‐120 ) . Devices in all groups could be changed at the discretion of the staff when signs of occlusion or increased resistance were identified . Measurements and Main Results : Daily measurements of inspired gas temperature , inspired relative humidity , and device resistance were made . Additionally , daily cultures of the patient side of the device were accomplished . The frequency rate of nosocomial pneumonia was made by using clinical criteria . Ventilatory support variables , airway care , device costs , and clinical indicators of humidification efficiency ( sputum volume , sputum efficiency ) were also recorded . Prolonged use of both hygroscopic and hydrophobic devices did not diminish efficiency or increase resistance . There was no difference in the number of colony‐forming units from device cultures over the 5‐day period and no difference between colony‐forming units in devices changed every 24 hrs compared with devices changed after 120 hrs . The average duration of use was 23 ± 4 hrs in the HHME‐24 group , 73 ± 13 hrs in the HME‐120 group , and 74 ± 9 hrs in the HHME‐120 group . Mean absolute humidity was greater for the hygroscopic devices ( 30.4 ± 1.1 mg of H2O/L ) compared with the hydrophobic devices ( 27.8 ± 1.3 mg of H2O/L ) . The frequency rate of nosocomial pneumonia was 8 % ( 8:100 ) in the HHME‐24 group , 8.3 % ( 5:60 ) in the HME‐120 group , and 6.6 % ( 4:60 ) in the HHME‐120 group . Pneumonia rates per 1000 ventilatory support days were 20:1000 in the HHME‐24 group , 20.8:1000 in the HME‐120 group , and 16.6:1000 in the HHME‐120 group . Costs per day were $ 3.24 for the HHME‐24 group , $ 2.98 for the HME‐120 group , and $ 1.65 for the HHME‐120 group . Conclusions : Changing the hydrophobic or hygroscopic HME after 3 days does not diminish efficiency , increase resistance , or alter bacterial colonization . The frequency rate of nosocomial pneumonia was also unchanged . Use of HMEs for > 24 hrs , up to 72 hrs , is safe and cost effective BACKGROUND The purpose of this study was to compare the performance of heat and moisture exchanger filters with heated humidifying systems in the mechanical ventilator circuit on the incidence of ventilator-associated pneumonia ( VAP ) and bacterial colonization . METHOD Two hundred and forty-three consecutive patients who required mechanical ventilation for 48 hours or more in the adult intensive care unit were r and omized to either a heat and moisture exchanger ( HME ) or a heated humidifying breathing circuit . RESULTS The VAP rate among the group with HME was 11.4 % ; the rate among the group with heated humidifying system ( HHS ) was 15.8 % . The difference was not statistically significant . Approximately 68 % of the patients in the HME group had no pathogen isolated compared with 50 % of the patients in the HHS group . This difference was statistically significant ( P = .006 ) . However , the distribution of the pathogens among those patients who had the isolated pathogens was mostly identical in the 2 groups . CONCLUSION Even though the study did not find HME to be significantly advantageous over the HHS , in as much as VAP rate is concerned , other advantages such as reduced nurses workload , reduced financial cost , and better safety made HME a more favorable device for use in our adult intensive care unit STUDY OBJECTIVE To determine the cost-effectiveness of continuous subglottic suctioning ( CSS ) as a strategy to decrease the incidence of  ventilator-associated pneumonia ( VAP ) .  DESIGN Decision-model analysis of the cost and efficacy of endotracheal tubes that allow CSS at preventing VAP . The primary outcome was cases of VAP averted . Model estimates were based on data from published prospect i ve trials of CSS and other prospect i ve studies of the incidence of VAP . SETTING AND PATIENTS Hypothetical cohort of 100 patients requiring nonelective endotracheal intubation and management in an ICU . INTERVENTIONS In the model , patients were managed with either traditional endotracheal tubes ( ETs ) or ETs capable of CSS . MEASUREMENTS AND MAIN RESULTS The marginal cost-effectiveness of CSS  was calculated as the savings result ing from cases of VAP averted minus the additional costs of CSS-ETs , and expressed as cost ( or savings ) per episode of VAP prevented . Sensitivity analysis of the impact of the major clinical inputs on the cost-effectiveness was performed . The base case assumed that the incidence of VAP in patients requiring > 72 h of mechanical ventilation ( MV ) was 25 % , that CSS-ETs had no impact on patients requiring MV for < 72 h , and that CSS-ETs result ed in a relative risk reduction of VAP of 30 % . Despite the higher costs of ETs capable of CSS , this tactic yielded a net savings of $ 4,992 per case of VAP prevented . For sensitivity analysis , model inputs were adjusted by 50 % individually and then simultaneously . This demonstrated the model to be only moderately sensitive to the calculated cost of VAP . With the relative risk reduction at 50 % of the base-case estimate , CSS result ed in $ 1,924 saved per case of VAP prevented . When all variables were skewed against CSS , total outlays were trivial ( approximately $ 14 per patient in the cohort ) . CONCLUSIONS CSS represents a strategy for the prevention of VAP that may result in savings . Further studies are warranted to confirm the efficacy of CSS This a r and omized clinical trial in which 20 patients were prospect ively evaluated for the incidence of ventilator-associated pneumonia ( VAP ) , of whom 12 received endotracheal suctioning by an open-suction method and 8 by a closed-suction method .  Differences in the incidence of VAP was not significantly different ( p = 0.4 ) between closed and open suctioning . Differences in Acute Physiology and Chronic Health Evaluation II , duration of entubation , and the use of steroids were all not significant . All patients in the study used H2 antagonist and a nasogastric tube . Proceeding with the study will involve a sample increase with a possible change in the results Nosocomial pneumonia is the leading cause of death among all hospital-acquired infections [ 1 ] . The estimated incidence of nosocomial pneumonia in intensive care units ranges from 10 % to 65 % ; most studies [ 2 - 6 ] show case fatality rates of more than 20 % . Ventilator-associated pneumonia specifically refers to nosocomial pneumonia that develops in a mechanically ventilated patient and that was not present at the time of airway intubation [ 7 ] . Various clinical risk factors have been associated with an increased incidence of ventilator-associated pneumonia , either because they predispose the patient to bacterial colonization of the oropharynx and stomach ( for example , the administration of antacids or histamine-2-receptor antagonists ) or because they facilitate aspiration of contaminated contents from these sites ( for example , supine positioning ) [ 1 , 2 , 8 , 9 ] . Craven and colleagues [ 10 ] first showed that the frequency of ventilator circuit changes also influences the incidence of ventilator-associated pneumonia . They found that changing circuits every 24 rather than every 48 hours was independently associated with the occurrence of nosocomial pneumonia [ 10 ] . This association has been attributed to increased manipulation of the patient , the endotracheal tube , and the ventilator circuit , which results in increased aspiration of contaminated tubing condensate or upper airway secretions [ 10 , 11 ] . More recently , several groups of investigators have found that ventilator circuits can be used safely for more than 48 hours without increasing the incidence of nosocomial pneumonia [ 12 - 16 ] . However , because of limitations in the design of these studies and the small number of patients prospect ively examined , the Centers for Disease Control and Prevention has given no clear recommendation for the maximum length of time that ventilator circuits can safely be left in place during prolonged mechanical ventilation [ 17 ] . This has result ed in the development of ambiguous guidelines about the frequency with which ventilator circuits should be changed [ 18 , 19 ] and in a call for well- design ed investigations to resolve this issue [ 20 ] . We did a r and omized , controlled trial to compare the effect and cost-efficacy of routine and no routine ventilator circuit changes in patients having prolonged mechanical ventilation . Our main goals were to determine 1 ) the incidence and outcome of ventilator-associated pneumonia in patients receiving scheduled ventilator circuit changes and 2 ) whether this incidence was increased in patients whose ventilator circuits remained unchanged . Methods Study Location and Patients The study was conducted at two university-affiliated teaching hospitals : Barnes Hospital ( 900 beds ) and Jewish Hospital ( 450 beds ) . During a 7-month period ( June 1994 to December 1994 ) , all patients receiving mechanical ventilation in the intensive care units of these hospitals ( surgical , trauma , medical , cardiothoracic , and neurosurgical units at Barnes Hospital ; surgical , medical , and cardiothoracic units at Jewish Hospital ) were potentially eligible for this investigation . Patients were entered into the trial if they were older than 18 years and had received mechanical ventilation for more than 5 days .  Mechanical ventilation for more than 5 days was predetermined , on the basis of our previous experience at these institutions [ 2 , 21 ] , to be necessary so that a more homogeneous cohort of patients requiring prolonged mechanical ventilation could be accrued . Patients were excluded if they were likely to be extubated within 24 hours of r and omization , if they had transferred from other hospitals and had already received mechanical ventilation for more than 24 hours , if they had had lung transplantation , or if they had active hemoptysis . Barnes Hospital and Jewish Hospital share the same respiratory therapy and infection control departments . The study was approved by the Washington University School of Medicine Human Studies Committee and the Institutional Review Board of Jewish Hospital . Both waived the requirement for informed consent because this study was a quality assessment of two low-risk practice s already in clinical use . Study Design Patients were r and omly assigned to receive no routine ventilator circuit changes or circuit changes every 7 days within 24 hours of meeting eligibility criteria . A schedule of changing ventilator circuits every 7 days was selected on the basis of available clinical data [ 12 - 16 ] and our survey of 16 regional medical centers ( DM Baker . Unpublished communication ) . Stratification according to hospital site was done before r and omization to control for differences in patient population s and health care personnel . R and omization within each hospital was done using opaque , sealed envelopes , which were opened at the time each patient was enrolled in the study . For the purpose s of this investigation , ventilator circuits were defined to include gas delivery tubing , humidifier water reservoirs , water traps , and medication delivery devices ( such as metered-dose inhaler chambers or adapters ) . Ventilator circuits could be changed at any time , at the discretion of individual care providers ( physicians , nurses , and respiratory therapists ) , secondary to a mechanical failure of the ventilator circuit ( such as an air leak ) or visible soil ( such as that result ing from hemoptysis or aspirated emesis ) . Scheduled ventilator circuit changes were done during the evening or night shifts to minimize the identification of individual patient group assignments to blinded investigators . All nonscheduled circuit changes were done when an appropriate indication for the circuit change ( that is , a mechanical defect or soil ) was identified . Patients transferred to the operating room for a surgical procedure ( such as tracheotomy ) or to diagnostic radiology received the same mechanical ventilator and circuit when they returned to the intensive care unit . The ventilators used for this study included Siemens Servo 900C ( Siemens-Elema Ventilator Systems , Schaumburg , Illinois ) , Puritan-Bennett 700 Series ( Puritan-Bennett Corporation , Carlsbad , California ) , and Bird 8400 Series ventilators ( Bird Products Corporation , Palm Springs , California ) . All ventilators were equipped with wick-type humidifiers ( Concha Therm III Plus , Hudson Respiratory Care , Inc. , Temecula , California ) filled with sterile irrigation water . All ventilator circuits were disposable ( Hudson Respiratory Care , Inc. , model 1613 ) and equipped with Y connectors . Each ventilator circuit had an attached trap for the collection 
    Output:
    
Therefore , strategies to decrease the incidence of VAP could decrease morbidity , mortality , and health care costs and improve patient safety .
This survey also showed that some effective strategies were used infrequently , suggesting inadequate translation of r and omized trial results into practice .