Table 2.
Summary of studies that evaluated patients using NHSN VAE criteria
| Emphasis | Design/Population | Summary | VAE Rates n (%) | |
|---|---|---|---|---|
| Klompas et al,7 2014 | Epidemiology and morbidity of VAE | Retrospective review at an academic medical center studying adult patients on MV over 5 y | 20,356 patients studied over 5 y showing VAEs corresponded with three times longer to extubate patients, increased hospital LOS by 50%, and doubled the risk of death compared with those that did not meet the criteria for VAE. Most frequent organisms were Staphylococcus aureus (29%), Pseudomonas aeruginosa (14%), and Enterobacter species (7.9%). | VAC 1141 (5.61) IVAC 431 (2.12) pVAP 139 (0.68) prVAP 127 (0.62) |
| Klouwenberg et al,6 2014 | Novel electronic surveillance mechanism to identify VAE | Multi-institutional prospective cohort study on mixed ICU patients | 2080 patients ventilated for >2 d. The VAE algorithm detected 32% of clinical VAP patients. Most VAC patients had volume overload and infections, but not necessarily VAP. Concordance between VAE algorithm and clinical VAP was poor. | VAC 158 (7.60) IVAC 66 (3.17) p/prVAP 51 (2.45) |
| Boyer et al,11 2015 | Prospectively evaluate VAE and VAC rates and preventability | Prospective cohort study at an academic medical center studying adult medical and surgical ICU patients | 1209 patients studied. Most common cause of VAC were IVACs (50.7%), ARDS (16.4%), pulmonary edema (14.9%), and atelectasis (9%). 37.3% of VACs were determined to be potentially preventable. The sensitivity of NHSN criteria for detecting VAP determined to be 25.9%. | VAC 77 (6.37) iVAC 34 (2.81) pVAP 6 (0.49) prVAP 15 (1.24) |
| Stoeppel et al,14 2014 | Applicability of NHSN VAE definitions in surgical ICU patients | Prospective cohort study at an academic medical center studying adult surgical and ICU patients | 437 surgical ICU patients of which only 37 met VAE criteria. Of the 400 other patients who did not meet VAE criteria, 111 (28%) had respiratory deterioration, 99 patients had clinical pneumonia. Most of these patients (58%) had <2 d of respiratory deterioration. Agreement between prVAP and clinical VAP was 77.3%. | VAC 37 (8.47) IVAC 31 (7.09) p/prVAP 22 (5.03) |
| Lewis et al,17 2014 | Evaluate risk factors for VAE | Retrospective case-controlled study at an academic medical center studying adult medical, surgical, cardiac, and neuroscience patients | 2990 patients analyzed and 110 case matched to control subjects showing significant risk factors in developing a VAE were mandatory modes of ventilation, positive fluid balance, starting benzodiazepines before intubation, total opioid exposure, and use of paralytic medications. | VAC 172 (5.75) IVAC 70 (2.34) |
| Lilly et al,9 2014 | Prevalence and characteristics of VAE | Prospective cohort study at two academic medical centers studying adult medical, surgical, cardiovascular, and neurologic ICU patients | 8408 MV patients discharged from ICU. NHSN VAE guidelines had a poor predictive value (0.07) of patients with clinically determined VAP. Most patients (71%) who met VAE/VAC criteria were diagnosed with ARDS. | VAC - 13.8/1000 MV days IVAC – 8.8/1000 MV days VAP – 2.96/1000 MV days |
| Resetar et al,18 2014 | Use of automated electronic surveillance to detect VAE from EMR data | Retrospective review at an academic medical center studying adult medical, surgical, cardiac, cardiothoracic, and neurologic ICU patients | 3691 patients with 19,105 MV days. Electronic VAE surveillance is a significant clinical and technical investment. The greatest cost was implementation and testing. | VAC 62 (1.67) IVAC 35 (0.94) pVAP 14 (0.38) prVAP 10 (0.27) |
| Stevens et al,8 2014 | Validation of automated algorithm to detect VAE | Retrospective cohort analysis at a tertiary care hospital studying adult medical and surgical ICU patients | 426 patients validated by human abstractor. The electronic algorithm had a net sensitivity of 93.5% and specificity of 100% and accuracy of 99.5% compared with the human reviewer. Algorithm took 0.16 s per patient compared with 17–30 min per patient for the human reviewer. | VAC 19 (4.46) IVAC 3 (0.70) pVAC 6 (1.41) prVAC 0 (0) |
| McMullen et al,15 2015 | Retrospective evaluation with an automated algorithm compared with prospective clinical evaluation | Retrospective review and prospective cohort study at an academic medical center studying adult medical and surgical patients | 1209 patients evaluated with both automated algorithms and prospective clinical evaluation showed good agreement between clinicians using NHSN definitions and automated algorithms to detect VAEs. | VAC 37 (3.06) IVAC 19 (1.57) pVAC 8 (0.66) prVAC 5 (0.41) |
| Nuckchady et al,19 2015 | Accuracy of automated surveillance techniques for VAE | Retrospective review at an academic medical center studying MV patients >48 h | 192 patients identified by billing records who were analyzed with an automated algorithm to detect VAE per the NHSN definitions. Sensitivity, specificity, PPV, and NPV all >93% and reduced the time spent on detection of VAEs by >90%. | VAC 44 (22.92) IVAC 22 (11.46) pVAC 12 (6.25) prVAC 1 (0.52) |
| Zhu et al,20 2015 | Impact of VAE surveillance on clinical outcomes | Multi-institutional prospective cohort study on adult medical and surgical patients | 2356 patients received MV for 8438 d. Compared with patients without VAEs those with VACs had longer ICU LOS (6.2 d), longer duration of MV (7.7 d), and higher hospital mortality rate (50% vs 27.3%). Patients with IVAC had longer duration of MV and increased LOS compared with those with VAC alone. | VAC 94 (3.99) IVAC 31 (1.32) pVAC 16 (0.68) prVAP 0 (0) |
| Klompas et al,3 2011 | Validation of a novel surveillance paradigm to identify complications of MV | Retrospective review at an academic medical center studying adult medical and surgical patients | 597 patients evaluated showing that VAP and VAC patients had prolonged intubation, ICU LOS, and hospital LOS. VAC was associated with increased mortality, but not VAP. | VAC 137 (23) VAP 56 (9.3)a |
| Prospero et al,21 2012 | Characterizing VAE rates | Prospective cohort study at an academic medical center studying adult MV patients | 127 patients analyzed with a significant increase in days of MV, ICU LOS, and mortality for those patients diagnosed with VAC compared VAC-negative patients. VAP patients showed increased mortality compared with non-VAP patients. | VAC 19 (15) VAP 2 (1.57)a |
| Muscedere et al,4 2013 | Impact and preventability of VAC | Multi-institutional retrospective study on adult medical, surgical, and trauma ICU patients | 1320 patients studied with an agreement between clinically diagnosed VAP and VAC of 0.18, VAP and IVAC and 0.19. Patients with VAC or IVAC had more ventilator days, hospital days, antibiotic days, and higher hospital mortality. Although the agreement between clinically diagnosed VAP and VAC/IVAC is poor these NHSN criteria define potential useful quality indicators. | VAC 139 (10.53) IVAC 65 (4.92) VAP 26 (1.97)a |
| Dessap et al,22 2014 | Evaluation of depletive fluid management on rates of VAC | Multi-institutional randomized controlled trial of adult ICU patients | 304 patients evaluated from the B-type Natriuretic Peptide for the Fluid Management of Weaning (BMC) trial showing that depletive fluid management was associated with significantly reduced rates of VAC and VAP. | VAC 40 (13.16) VAP 17 (5.60)a |
Abbreviations: MV, mechanical ventilation; NPV, negative predictive value; PPV, positive predictive value; prVAP, probable VAP; pVAP, possible VAP.
a
VAP diagnosis made using additional clinical findings not specified in the NHSN surveillance guidelines.