Comparison between a clinical diagnosis method and the surveillance technique of the Center for Disease Control and Prevention for identification of mechanical ventilator-associated pneumonia

Comparison of multiple definitions for ventilator-associated pneumonia in patients requiring mechanical ventilation for non-pulmonary conditions: preliminary data from PULMIVAP, an Italian multi-centre cohort study

OBJECTIVES

To compare intensivist-diagnosed ventilator-associated pneumonia (iVAP) with four established definitions, assessing their agreement in detecting new episodes.

METHODS

A multi-centric prospective study on pulmonary microbiota was carried out in patients requiring mechanical ventilation (MV). Data collected were used to compare hypothetical VAP onset according to iVAP with the study consensus criteria, the European Centre for Disease Control and Prevention definition, and two versions of the latter adjusted for leukocyte count and fever.

RESULTS

In our cohort of 186 adult patients, iVAPs were 36.6% (68/186, 95% confidence interval 30.0-44.0%), with an incidence rate of 4.64/100 patient-MV-days, and median MV-day at diagnosis of 6. Forty-seven percent of patients (87/186) were identified as VAP by at least one criterion, with a median MV-day at diagnosis of 5. Agreement between intensivist judgement (iVAP/no-iVAP) and the criteria was highest for the study consensus criteria (50/87, 57.4%), but still one-third of iVAP were not identified and 9% of patients were identified as VAP contrary to intensivist diagnosis. VAP proportion differed between criteria (25.2-30.1%).

CONCLUSIONS

Caution is needed when evaluating studies describing VAP incidence. Pre-agreed criteria and definitions that capture VAP's evolving nature provide greater consistency, but new clinically driven definitions are needed to align surveillance and diagnostic criteria with clinical practice.

Impact of a national collaborative project to improve the care of mechanically ventilated patients

This prospective quasi-experimental study from the NASAM (National Approach to Standardize and Improve Mechanical Ventilation) collaborative assessed the impact of evidence-based practices including subglottic suctioning, daily assessment for spontaneous awakening trial (SAT), spontaneous breathing trial (SBT), head of bed elevation, and avoidance of neuromuscular blockers unless otherwise indicated. The study outcomes included VAE (primary) and intensive care unit (ICU) mortality. Changes in daily care process measures and outcomes were evaluated using repeated measures mixed modeling. The results were reported as incident rate ratio (IRR) for each additional month with 95% confidence interval (CI). A comprehensive program that included education on evidence-based practices for optimal care of mechanically ventilated patients with real-time benchmarking of daily care process measures to drive improvement in forty-two ICUs from 26 hospitals in Saudi Arabia (>27,000 days of observation). Compliance with subglottic suctioning, SAT and SBT increased monthly during the project by 3.5%, 2.1% and 1.9%, respectively (IRR 1.035, 95%CI 1.007-1.064, p = 0.0148; 1.021, 95% CI 1.010-1.032, p = 0.0003; and 1.019, 95%CI 1.009-1.029, p = 0.0001, respectively). The use of neuromuscular blockers decreased monthly by 2.5% (IRR 0.975, 95%CI 0.953-0.998, p = 0.0341). The compliance with head of bed elevation was high at baseline and did not change over time. Based on data for 83153 ventilator days, VAE rate was 15.2/1000 ventilator day (95%CI 12.6-18.1) at baseline and did not change during the project (IRR 1.019, 95%CI 0.985-1.053, p = 0.2812). Based on data for 8523 patients; the mortality was 30.4% (95%CI 27.4-33.6) at baseline, and decreased monthly during the project by 1.6% (IRR 0.984, 95%CI 0.973-0.996, p = 0.0067). A national quality improvement collaborative was associated with improvements in daily care processes. These changes were associated with a reduction in mortality but not VAEs. Registration The study is registered in clinicaltrials.gov (NCT03790150).

Determinants of macrosomia among newborns delivered in northwest Ethiopia: a case–control study

Objective

Macrosomia is associated with the risk of mortality and morbidity in neonates and their mothers. Despite the considerable public health effect of macrosomia, evidence on the determinants of macrosomia is limited in Northwest Ethiopia in general and in Amhara region in particular. Therefore, this study aimed to identify determinants of macrosomia among newborns delivered in referral hospitals in 2020 in Amhara region, Northwest Ethiopia.

Methods

A facility-based unmatched case-control study was conducted among 279 mothers and their newborns in Amhara region referral hospitals. Newborns weighing 4000 g and above and between 2500 and 3999 g were considered cases and controls, respectively. Bivariable and multivariable binary logistic regression were used to identify the determinants of macrosomia.

Results

In total, 273 of 279 mothers and their newborns (97.8% response rate) were included. The mean birth weights of cases and controls were 4312.97 ± 357.53 g and 3161.92 ± 452.12 g, respectively. Weight gain over pregnancy, antenatal follow up, physical activity during pregnancy, and neonate sex were the main determinants of macrosomia.

Conclusion

The main determinants of macrosomia were determined in this study. Government should place special emphasis on reducing the modifiable factors of macrosomia.

Analysis of diagnostic criteria for ventilator-associated pneumonia: a cohort study

OBJECTIVES

to analyze the diagnostic criteria for ventilator-associated pneumonia recommended by the Brazilian Health Regulatory Agency and the National Healthcare Safety Network/Centers for Disease Control and Prevention, as well as its risk factors.

METHODS

retrospective cohort study carried out in an intensive care unit throughout 12 months, in 2017. Analyses included chi-square, simple linear regression, and Kappa statistical tests and were conducted using Stata 12 software.

RESULTS

the sample was 543 patients who were in the intensive care unit and under mechanical ventilation, of whom 330 (60.9%) were men and 213 (39.1%) were women. Variables such as gender, age, time under mechanical ventilation, and oral hygiene proved to be significant risk factors for the development of ventilator-associated pneumonia.

CONCLUSIONS

patients submitted to mechanical ventilation need to be constantly evaluated so the used diagnostic methods can be accurate and applied in an objective and standardized way in Brazilian hospitals.

Systematic review of studies investigating ventilator associated pneumonia diagnostics in intensive care

Background

Ventilator-associated pneumonia (VAP) is an important diagnosis in critical care. VAP research is complicated by the lack of agreed diagnostic criteria and reference standard test criteria. Our aim was to review which reference standard tests are used to evaluate novel index tests for suspected VAP.

Methods

We conducted a comprehensive search using electronic databases and hand reference checks. The Cochrane Library, MEDLINE, CINHAL, EMBASE, and web of science were searched from 2008 until November 2018. All terms related to VAP diagnostics in the intensive treatment unit were used to conduct the search. We adopted a checklist from the critical appraisal skills programme checklist for diagnostic studies to assess the quality of the included studies.

Results

We identified 2441 records, of which 178 were selected for full-text review. Following methodological examination and quality assessment, 44 studies were included in narrative data synthesis. Thirty-two (72.7%) studies utilised a sole microbiological reference standard; the remaining 12 studies utilised a composite reference standard, nine of which included a mandatory microbiological criterion. Histopathological criteria were optional in four studies but mandatory in none.

Conclusions

Nearly all reference standards for VAP used in diagnostic test research required some microbiological confirmation of infection, with BAL culture being the most common reference standard used.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01560-0.

A comparison of diagnostic algorithms and clinical parameters to diagnose ventilator-associated pneumonia: a prospective observational study

Background

Suspicion and clinical criteria continue to serve as the foundation for ventilator-associated pneumonia (VAP) diagnosis, however the criteria used to diagnose VAP vary widely. Data from head-to-head comparisons of clinical diagnostic algorithms is lacking, thus a prospective observational study was performed to determine the performance characteristics of the Johanson criteria, Clinical Pulmonary Infection Score (CPIS), and Centers for Disease Control and Prevention’s National Healthcare Safety Network (CDC/NHSN) criteria as compared to Hospital in Europe Link for Infection Control through Surveillance (HELICS) reference standard.

Methods

A prospective observational cohort study was performed in three mixed medical-surgical ICUs from one academic medical center from 1 October 2016 to 30 April 2018. VAP diagnostic criteria were applied to each patient including CDC/NHSN, CPIS, HELICS and Johanson criteria. Tracheal aspirate cultures (TAC) and serum procalcitonin values were obtained for each patient.

Results

Eighty-five patients were enrolled (VAP 45, controls 40). Using HELICS as the reference standard, the sensitivity and specificity for each of the assessed diagnostic algorithms were: CDC/NHSN (Sensitivity 54.2%; Specificity 100%), CPIS (Sensitivity 68.75%; Specificity 95.23%), Johanson (Sensitivity 67.69%; Specificity 95%). The positive TAC rate was 81.2%. The sensitivity for positive TAC with the serum procalcitonin level > 0.5 ng/ml was 51.8%.

Conclusion

VAP remains a considerable source of morbidity and mortality in modern intensive care units. The optimal diagnostic method remains unclear. Using HELICS criteria as the reference standard, CPIS had the greatest comparative diagnostic accuracy, whereas the sensitivity of the CDC/NHSN was only marginally better than a positive TAC plus serum procalcitonin > 0.5 ng/ml. Algorithm accuracy was improved by adding serum procalcitonin > 0.5 ng/ml, but not positive quantitative TAC.

Trial Registration: Not indicated for this study type.

Concordance between the National Healthcare Safety Network (NHSN) Surveillance Criteria and Clinical Pulmonary Infection Score (CPIS) Criteria for Diagnosis of Ventilator-associated Pneumonia (VAP)

Background: Ventilator-associated pneumonia (VAP) is one of the most common hospital-acquired infections among mechanically ventilated patients and the incidence rates are widely used as an index of quality of care given in an ICU. Since there is no gold standard method available to diagnose VAP, the incidence rate varies based on different criteria used for calculation. Therefore, we conducted a study to determine the concordance between the National Healthcare Safety Network (NHSN) surveillance criteria and clinical pulmonary infection score (CPIS) criteria for the diagnosis of VAP.

Materials and methods: This was a prospective study that evaluated patients in the medical intensive care units (MICUs) of a tertiary care hospital, India, who were intubated for >48 hours between October 2018 and September 2019. All the patients (n = 273) were followed up daily and assessed using both CPIS and NHSN surveillance criteria for diagnosing VAP.

Results: Of these 273 patients, 93 patients (34.1%) had VAP according to CPIS criteria as compared with 33 patients (12.1%) using the NHSN criteria. The corresponding rates of VAP were 39.59 vs 11.53 cases per 1,000 ventilator days, respectively. The agreement of the two sets of criteria was fairly good (kappa statistics, 0.42)

Conclusion: The NHSN surveillance criteria have a lower sensitivity in detecting VAP cases and have to be modified to achieve better results.

How to cite this article: Gunalan A, Sistla S, Sastry AS, Venkateswaran R. Concordance between the National Healthcare Safety Network (NHSN) Surveillance Criteria and Clinical Pulmonary Infection Score (CPIS) Criteria for Diagnosis of Ventilator-associated Pneumonia (VAP). Indian J Crit Care Med 2021;25(3):296–298.

Outcomes of ventilatory asynchrony in patients with inspiratory effort

Objective

To identify the relationship of patient-ventilator asynchrony with the level of sedation and hemogasometric and clinical results.

Methods

This was a prospective study of 122 patients admitted to the intensive care unit who underwent > 24 hours of invasive mechanical ventilation with inspiratory effort. In the first 7 days of ventilation, patient-ventilator asynchrony was evaluated daily for 30 minutes. Severe patient-ventilator asynchrony was defined as an asynchrony index > 10%.

Results

A total of 339,652 respiratory cycles were evaluated in 504 observations. The mean asynchrony index was 37.8% (standard deviation 14.1 - 61.5%). The prevalence of severe patient-ventilator asynchrony was 46.6%. The most frequent patient-ventilator asynchronies were ineffective trigger (13.3%), autotrigger (15.3%), insufficient flow (13.5%), and delayed cycling (13.7%). Severe patient-ventilator asynchrony was related to the level of sedation (ineffective trigger: p = 0.020; insufficient flow: p = 0.016; premature cycling: p = 0.023) and the use of midazolam (p = 0.020). Severe patient-ventilator asynchrony was also associated with hemogasometric changes. The persistence of severe patient-ventilator asynchrony was an independent risk factor for failure of the spontaneous breathing test, ventilation time, ventilator-associated pneumonia, organ dysfunction, mortality in the intensive care unit, and length of stay in the intensive care unit.

Conclusion

Patient-ventilator asynchrony is a frequent disorder in critically ill patients with inspiratory effort. The patient’s interaction with the ventilator should be optimized to improve hemogasometric parameters and clinical results. Further studies are required to confirm these results.

Evaluation of the Use of Novel Biomarkers to Augment Antimicrobial Stewardship Program Activities

As antimicrobial stewardship increasingly receives worldwide attention for improving patient care by optimizing antimicrobial therapy, programs are evaluating new tools that may augment antimicrobial stewardship activities. Biomarkers are objective, accurate, and reproducible measures that provide information about medical conditions. A systematic literature search using PubMed/MEDLINE databases was performed to evaluate the use of novel biomarkers as additions to the antimicrobial stewardship armamentarium. Procalcitonin may help clinicians discriminate between bacterial and viral infections, help with antimicrobial discontinuation decisions, and predict mortality. β-d-glucan, Candida albicans germ tube antibody, and galactomannan are useful in suspected fungal infections and may reduce inappropriate antifungal use. Adrenomedullin and soluble triggering receptor on myeloid cells-1 may be useful for mortality prediction and the determination of a need for empiric antibacterials. Although studies evaluating these biomarkers are promising, these biomarkers are not without limitations and should be used in combination with clinical signs, symptoms, or other biomarkers. For successful implementation of biomarker use, stewardship programs should consider the populations most likely to benefit, without using them indiscriminately in all patients. Antimicrobial stewardship programs should facilitate education of clinicians through institutional guidelines to ensure the appropriate use and interpretation of these biomarkers.

Ventilator-associated respiratory infection in a resource-restricted setting: impact and etiology

Background

Ventilator-associated respiratory infection (VARI) is a significant problem in resource-restricted intensive care units (ICUs), but differences in casemix and etiology means VARI in resource-restricted ICUs may be different from that found in resource-rich units. Data from these settings are vital to plan preventative interventions and assess their cost-effectiveness, but few are available.

Methods

We conducted a prospective observational study in four Vietnamese ICUs to assess the incidence and impact of VARI. Patients ≥ 16 years old and expected to be mechanically ventilated > 48 h were enrolled in the study and followed daily for 28 days following ICU admission.

Results

Four hundred fifty eligible patients were enrolled over 24 months, and after exclusions, 374 patients’ data were analyzed. A total of 92/374 cases of VARI (21.7/1000 ventilator days) were diagnosed; 37 (9.9%) of these met ventilator-associated pneumonia (VAP) criteria (8.7/1000 ventilator days). Patients with any VARI, VAP, or VARI without VAP experienced increased hospital and ICU stay, ICU cost, and antibiotic use (p < 0.01 for all). This was also true for all VARI (p < 0.01 for all) with/without tetanus. There was no increased risk of in-hospital death in patients with VARI compared to those without (VAP HR 1.58, 95% CI 0.75–3.33, p = 0.23; VARI without VAP HR 0.40, 95% CI 0.14–1.17, p = 0.09). In patients with positive endotracheal aspirate cultures, most VARI was caused by Gram-negative organisms; the most frequent were Acinetobacter baumannii (32/73, 43.8%) Klebsiella pneumoniae (26/73, 35.6%), and Pseudomonas aeruginosa (24/73, 32.9%). 40/68 (58.8%) patients with positive cultures for these had carbapenem-resistant isolates. Patients with carbapenem-resistant VARI had significantly greater ICU costs than patients with carbapenem-susceptible isolates (6053 USD (IQR 3806–7824) vs 3131 USD (IQR 2108–7551), p = 0.04) and after correction for adequacy of initial antibiotics and APACHE II score, showed a trend towards increased risk of in-hospital death (HR 2.82, 95% CI 0.75–6.75, p = 0.15).

Conclusions

VARI in a resource-restricted setting has limited impact on mortality, but shows significant association with increased patient costs, length of stay, and antibiotic use, particularly when caused by carbapenem-resistant bacteria. Evidence-based interventions to reduce VARI in these settings are urgently needed.

Electronic supplementary material

The online version of this article (10.1186/s40560-017-0266-4) contains supplementary material, which is available to authorized users.

New diagnostic methods for pneumonia in the ICU

PURPOSE OF REVIEW

Pneumonia leading to severe sepsis and critical illness including respiratory failure remains a common and therapeutically challenging diagnosis. Current clinical approaches to surveillance, early detection, and conventional culture-based microbiology are inadequate for optimal targeted antibiotic treatment and stewardship. Efforts to enhance diagnosis of community-acquired and health care-acquired pneumonia, including ventilator-associated pneumonia (VAP), are the focus of recent studies reviewed here.

RECENT FINDINGS

Newer surveillance definitions are sensitive for pneumonia in the ICU including VAP but consistently underdetect patients that are clinically shown to have bacterial VAP based on clinical diagnostic criteria and response to antibiotic treatment. Routinely measured plasma biomarkers, including procalcitonin and C-reactive protein, lack sufficient precision and predictive accuracy to inform diagnosis. Novel rapid microbiological diagnostics, including nucleic-acid amplification, mass spectrometry, and fluorescence microscopy-based technologies are promising approaches for the future. Exhaled breath biomarkers, including measurement of volatile organic compounds, represent a future approach.

SUMMARY

The integration of novel diagnostics for rapid microbial identification, resistance phenotyping, and antibiotic sensitivity testing into usual care practice could significantly transform the care of patients and potentially inform significantly improved targeted antimicrobial selection, de-escalation, and stewardship.