***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: Ventilator-associated pneumonia ( VAP ) , an infection of the lower respiratory tract which occurs in association with mechanical ventilation , is one of the most common causes of nosocomial infection in the intensive care unit ( ICU ) . VAP causes significant morbidity and mortality in critically ill patients including increased duration of mechanical ventilation , ICU stay and hospitalization . Current knowledge for its prevention , diagnosis and management is therefore important clinical ly and is the basis for this review . We discuss recent changes in VAP surveillance nomenclature incorporating ventilator-associated conditions and ventilator-associated events , terms recently proposed by the Centers for Disease Control . To the extent possible , we rely predominantly on data from r and omized control trials ( RCTs ) and meta-analyses BACKGROUND A study was undertaken to assess the diagnostic value of different clinical criteria and the impact of microbiological testing on the accuracy of clinical diagnosis of suspected ventilator associated pneumonia ( VAP ) . METHODS Twenty five deceased mechanically ventilated patients were studied prospect ively . Immediately after death , multiple bilateral lung biopsy specimens ( 16 specimens/patient ) were obtained for histological examination and quantitative lung cultures . The presence of both histological pneumonia and positive lung cultures was used as a reference test . RESULTS The presence of infiltrates on the chest radiograph and two of three clinical criteria ( leucocytosis , purulent secretions , fever ) had a sensitivity of 69 % and a specificity of 75 % ; the corresponding numbers for the clinical pulmonary infection score ( CPIS ) were 77 % and 42 % . Non-invasive as well as invasive sampling techniques had comparable values . The combination of all techniques achieved a sensitivity of 85 % and a specificity of 50 % , and these values remained virtually unchanged despite the presence of previous treatment with antibiotics . When microbiological results were added to clinical criteria , adequate diagnoses originating from microbiological results which might have corrected false positive and false negative clinical judgements ( n = 5 ) were countered by a similar proportion of inadequate diagnoses ( n = 6 ) . CONCLUSIONS Clinical criteria had reasonable diagnostic values . CPIS was not superior to conventional clinical criteria . Non-invasive and invasive sampling techniques had diagnostic values comparable to clinical criteria . An algorithm guiding antibiotic treatment exclusively by microbiological results does not increase the overall diagnostic accuracy and carries the risk of undertreatment BACKGROUND The Centers for Disease Control and Prevention has shifted policy away from using ventilator-associated pneumonia ( VAP ) and toward using ventilator-associated conditions ( VACs ) as a marker of ICU quality . To date , limited prospect i ve data regarding the incidence of VAC among medical and surgical ICU patients , the ability of VAC criteria to capture patients with VAP , and the potential clinical preventability of VACs are available . METHODS This study was a prospect i ve 12-month cohort study ( January 2013 to December 2013 ) . RESULTS We prospect ively surveyed 1,209 patients ventilated for ≥ 2 calendar days . Sixty-seven VACs were identified ( 5.5 % ) , of which 34 ( 50.7 % ) were classified as an infection-related VAC ( IVAC ) with corresponding rates of 7.0 and 3.6 per 1,000 ventilator days , respectively . The mortality rate of patients having a VAC was significantly greater than that of patients without a VAC ( 65.7 % vs 14.4 % , P < .001 ) . The most common causes of VACs included IVACs ( 50.7 % ) , ARDS ( 16.4 % ) , pulmonary edema ( 14.9 % ) , and atelectasis ( 9.0 % ) . Among IVACs , 44.1 % were probable VAP and 17.6 % were possible VAP . Twenty-five VACs ( 37.3 % ) were adjudicated to represent potentially preventable events . Eighty-six episodes of VAP occurred in 84 patients ( 10.0 of 1,000 ventilator days ) during the study period . The sensitivity of the VAC criteria for the detection of VAP was 25.9 % ( 95 % CI , 16.7%-34.5 % ) . CONCLUSIONS Although relatively uncommon , VACs are associated with greater mortality and morbidity when they occur . Most VACs represent nonpreventable events , and the VAC criteria capture a minority of VAP episodes Background Ventilator-associated pneumonia ( VAP ) surveillance is time consuming , subjective , inaccurate , and inconsistently predicts outcomes . Shifting surveillance from pneumonia in particular to complications in general might circumvent the VAP definition 's subjectivity and inaccuracy , facilitate electronic assessment , make interfacility comparisons more meaningful , and encourage broader prevention strategies . We therefore evaluated a novel surveillance paradigm for ventilator-associated complications ( VAC ) defined by sustained increases in patients ' ventilator setting s after a period of stable or decreasing support . Methods We assessed 600 mechanically ventilated medical and surgical patients from three hospitals . Each hospital contributed 100 r and omly selected patients ventilated 2–7 days and 100 patients ventilated > 7 days . All patients were independently assessed for VAP and for VAC . We compared incidence-density , duration of mechanical ventilation , intensive care and hospital lengths of stay , hospital mortality , and time required for surveillance for VAP and for VAC . A subset of patients with VAP and VAC were independently review ed by a physician to determine possible etiology . Results Of 597 evaluable patients , 9.3 % had VAP ( 8.8 per 1,000 ventilator days ) and 23 % had VAC ( 21.2 per 1,000 ventilator days ) . Compared to matched controls , both VAP and VAC prolonged days to extubation ( 5.8 , 95 % CI 4.2–8.0 and 6.0 , 95 % CI 5.1–7.1 respectively ) , days to intensive care discharge ( 5.7 , 95 % CI 4.2–7.7 and 5.0 , 95 % CI 4.1–5.9 ) , and days to hospital discharge ( 4.7 , 95 % CI 2.6–7.5 and 3.0 , 95 % CI 2.1–4.0 ) . VAC was associated with increased mortality ( OR 2.0 , 95 % CI 1.3–3.2 ) but VAP was not ( OR 1.1 , 95 % CI 0.5–2.4 ) . VAC assessment was faster ( mean 1.8 versus 39 minutes per patient ) . Both VAP and VAC events were predominantly attributable to pneumonia , pulmonary edema , ARDS , and atelectasis . Conclusions Screening ventilator setting s for VAC captures a similar set of complications to traditional VAP surveillance but is faster , more objective , and a superior predictor of outcomes Objectives : Correct classification of the source of infection is important in observational and interventional studies of sepsis . Centers for Disease Control and Prevention criteria are most commonly used for this purpose , but the robustness of these definitions in critically ill patients is not known . We hypothesized that in a mixed ICU population , the performance of these criteria would be generally reduced and would vary among diagnostic subgroups . Design : Prospect i ve cohort . Setting : Data were collected as part of a cohort of 1,214 critically ill patients admitted to two hospitals in The Netherl and s between January 2011 and June 2011 . Patients : Eight observers assessed a r and om sample of 168 of 554 patients who had experienced at least one infectious episode in the ICU . Each patient was assessed by two r and omly selected observers who independently scored the source of infection ( by affected organ system or site ) , the plausibility of infection ( rated as none , possible , probable , or definite ) , and the most likely causative pathogen . Assessment s were based on a post hoc review of all available clinical , radiological , and microbiological evidence . The observed diagnostic agreement for source of infection was classified as partial ( i.e. , matching on organ system or site ) or complete ( i.e. , matching on specific diagnostic terms ) , for plausibility as partial ( 2-point scale ) or complete ( 4-point scale ) , and for causative pathogens as an approximate or exact pathogen match . Interobserver agreement was expressed as a concordant percentage and as a kappa statistic . Interventions : None . Measurements and Main Results : A total of 206 infectious episodes were observed . Agreement regarding the source of infection was 89 % ( 183/206 ) and 69 % ( 142/206 ) for a partial and complete diagnostic match , respectively . This result ed in a kappa of 0.85 ( 95 % CI , 0.79–0.90 ) . Agreement varied from 63 % to 91 % within major diagnostic categories and from 35 % to 97 % within specific diagnostic subgroups , with the lowest concordance observed in cases of ventilator-associated pneumonia . In the 142 episodes for which a complete match on source of infection was obtained , the interobserver agreement for plausibility of infection was 83 % and 65 % on a 2- and 4-point scale , respectively . For causative pathogen , agreement was 78 % and 70 % for an approximate and exact pathogen match , respectively . Conclusions : Interobserver agreement for classifying sources of infection using Centers for Disease Control and Prevention criteria was excellent overall . However , full concordance on all aspects of the diagnosis between independent observers was rare for some types of infection , in particular for ventilator-associated pneumonia Purpose Early hyperoxia may be an independent risk factor for mortality in mechanically ventilated intensive care unit ( ICU ) patients . We examined the relationship between early arterial oxygen tension ( PaO2 ) and in-hospital mortality . Method We retrospectively assessed  arterial blood gases ( ABG ) with ‘ worst ’ alveolar-arterial ( A-a ) gradient during the first 24 h of ICU admission for all ventilated adult patients from 150 participating ICUs between 2000 and 2009 . We used multivariate analysis in all patients and defined subgroups to determine the relationship between PaO2 and mortality . We also studied the relationship between worst PaO2 , admission PaO2 and peak PaO2 in a r and om cohort of patients . Results We studied 152,680 patients . Their mean PaO2 was 20.3 kPa ( SD 14.6 ) and mean inspired fraction of oxygen ( FiO2 ) was 62 % ( SD 26 ) . Worst A-a gradient ABG identified that 49.8 % ( 76,110 ) had hyperoxia ( PaO2 > 16 kPa ) . Nineteen per cent of patients died in ICU and 26 % in hospital . After adjusting for site , Simplified Acute Physiology Score II ( SAPS II ) , age , FiO2 , surgical type , Glasgow Coma Scale ( GCS ) below 15 and year of ICU admission , there was an association between progressively lower PaO2 and increasing in-hospital mortality , but not with increasing levels of hyperoxia . Similar findings were observed with a sensitivity analysis of PaO2 derived from high FiO2 ( ≥50 % ) versus low FiO2 ( < 50 % ) and in defined subgroups . Worst PaO2 showed a strong correlation with admission PaO2 ( r = 0.98 ) and peak PaO2 within 24 h of admission ( r = 0.86 ) . Conclusion We found there was an association between hypoxia and increased in-hospital mortality , but not with hyperoxia in the first 24 h in ICU and mortality in ventilated patients . Our findings differ from previous studies and suggest that the impact of early hyperoxia on mortality remains uncertain Objectives : Centers for Disease Control and Prevention built up new surveillance paradigms for the patients on mechanical ventilation and the ventilator-associated events , comprising ventilator-associated conditions and infection-related ventilator-associated complications . We assess 1 ) the current epidemiology of ventilator-associated event , 2 ) the relationship between ventilator-associated event and ventilator-associated pneumonia , and 3 ) the impact of ventilator-associated event on antimicrobials consumption and mechanical ventilation duration . Design : Inception cohort study from the longitudinal prospect i ve French multicenter OUTCOME REA data base ( 1996 - 2012 ) . Patients : Patients on mechanical ventilation for greater than or equal to 5 consecutive days were classified as to the presence of a ventilator-associated event episode , using slightly modified Centers for Disease Control and Prevention definitions . Intervention : None . Measurements and Main Results : Among the 3,028 patients , 2,331 patients ( 77 % ) had at least one ventilator-associated condition , and 869 patients ( 29 % ) had one infection-related ventilator-associated complication episode . Multiple causes , or the lack of identified cause , were frequent . The leading causes associated with ventilator-associated condition and infection-related ventilator-associated complication were nosocomial infections ( 27.3 % and 43.8 % ) , including ventilator-associated pneumonia ( 14.5 % and 27.6 % ) . Sensitivity and specificity of diagnosing ventilator-associated pneumonia were 0.92 and 0.28 for ventilator-associated condition and 0.67 and 0 
    Output:
    
Conclusions VAE surveillance missed many cases of VAP , and the population characteristics identified by the two surveillance paradigms differed .
VAE surveillance does not accurately detect cases of traditional VAP in ICUs