A simple method of bronchoalveolar lavage

Skin bacterial richness and diversity in intensive care unit patients with severe pneumonia

OBJECTIVES

Patients with severe pneumonia admitted to the intensive care unit (ICU) have a high risk of mortality, and the microbiome is likely to affect the outcome of such patients. However, the composition of the skin microbiota of ICU patients with severe pneumonia remains unclear. In this study, on the basis of 16S ribosomal ribonucleic acid sequencing, we explored the difference in skin bacterial richness and diversity between the ICU patient group (PG) with severe pneumonia and the healthy control group (CG).

METHODS

The diversity index and taxonomic distribution of skin bacteria were analyzed using the Quantitative Insights Into Microbial Ecology (QIIME) bioinformatics pipeline. Blood, endotracheal aspirate, and bronchoalveolar lavage fluid samples were collected from the same PG subjects for culture.

RESULTS

Compared with the CG, the diversity of skin bacteria in the PG decreased significantly. Staphylococcus, Acinetobacter, Stenotrophomonas, Enterococcus, Halomonas, and Brevibacillus were differentially abundant in the PG, and most of these bacteria were also identified in the cultures of upper respiratory tract samples of the same PG.

CONCLUSION

We provide evidence that healthcare-associated infection in ICU patients with severe pneumonia is strongly associated with skin microbiota, which necessitates the prevention and control of skin bacterial pathogens for these patients.

Soluble triggering receptor expressed on myeloid cells-1 as a useful biomarker for diagnosing ventilator-associated pneumonia after congenital cardiac surgery in children

The present study aimed to assess the usefulness of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) in the diagnosis of ventilator-associated pneumonia (VAP) in paediatric patients with congenital heart disease (CHD) following cardiac surgery. The current prospective study enrolled 48 patients with congenital heart diseases who were suspected of having VAP; these patients were undergoing cardiac surgery between August 2016 and October 2017 in the Cardiac Intensive Care Unit of Shanghai Children's Medical Center (Shanghai, China). A total of 31 patients were diagnosed with VAP using a polymerase chain reaction (PCR) assay, while 17 patients without VAP were designated as the Non-VAP group. A bronchoscopy was performed and samples were collected for measurement on the day that VAP was diagnosed. The sTREM-1 levels were measured in bronchoalveolar lavage fluid (BALF) and exhaled ventilator condensate (EVC). BALF specimens were also sent to the microbiology laboratory for PCR assays and quantitative culturing. The positive detection rate of bacteria using the PCR assay and traditional culture was 64.6% (31/48) and 39.6% (19/48). sTREM-1 was significantly higher in the BALF (146.21 pg/ml vs. 118.06 pg/ml) and EVC (125.29 pg/ml vs. 120.48 pg/ml) of patients with VAP demonstrated compared with the patients without VAP. The findings suggest that the detection of sTREM-1 in BALF and EVC samples may be useful for the diagnosis of VAP following heart surgery in children.

Diagnostic Performance of Soluble Triggering Receptor Expressed on Myeloid Cells-1 in Ventilator-Associated Pneumonia of Patients with Ischemic Stroke

Objective. To investigate the effect of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in serum, bronchoalveolar lavage fluid (BALF), endotracheal aspiration (ETA), and exhaled breath condensate (EBC) samples as early biomarkers for the diagnosis of ventilator-associated pneumonia (VAP) in patients with ischemic stroke. Methods. One hundred and thirty-two patients with clinically suspected VAP were enrolled in this study. Bronchoscopy was performed on the day of clinically suspected VAP. sTREM-1 levels in serum, BALF, ETA, and EBC were measured. VAP was diagnosed by quantitative cultures of BALF (≥10⁴ cfu/mL). Results. VAP was confirmed in 76 (57.58%) cases. Patients with VAP showed significantly higher sTREM-1 in BALF [32.35 (IQR, 30.08–41.72) versus 18.92 (11.89–31.72)] pg/mL and in EBC [1.57 (IQR, 1.02–2.61) versus 0.41 (0.19–1.61)] pg/mL than patients without VAP. The area under the curve was 0.813 (p < 0.001). The optimum cut-off value for sTREM-1 in BALF was 23.61 pg/mL, yielding sensitivity and specificity of 85.5% and 73.1%. sTREM-1 in BALF had excellent correlation with that in EBC (R² = 0.78, p < 0.05). Conclusions. sTREM-1 in EBC and BALF had good diagnostic performance in differentiating patients with and without VAP.

Pneumocystis Carinii Pneumonia in Adult Non-HIV Disorders

Pneumocystis carinii pneumonia (PCP) remains a serious infection in the immunocompromised host (in the absence of HIV infection) and presents significant management and diagnostic challenges to ICU physicians. Non-HIV PCP is generally abrupt in onset, and follows a fulminate course with high rates of hospitalization, ICT admission, respiratory failure, and requirement for intubation. Mortality is generally high, especially if mechanical ventilation is required. Non-invasive ventilatory support may be considered, although the rapid progression to respiratory failure often necessitates intubation at the time of presentation. Bronchoscopy is often required to establish the diagnosis, and empirical antimicrobial treatment specifically targeted to P. carinii should be initiated while awaiting confirmation. Adjunctive corticosteroids may accelerate recovery, although their use has not yet been established in non-HIV PCP. For the ICU physicians to diagnose PCP, the non-specific presentation of an acute febrile illness and respiratory distress with diffuse pulmonary infiltrates requires a high clinical index of suspician, familiarity with clinical conditions associated with increased risk for PCP, and a low threshold for bronchoscopy to establish the diagnosis.

Role of soluble triggering receptor expressed on myeloid cells-1 for diagnosing ventilator-associated pneumonia after cardiac surgery: an observational study

Background

The diagnosis of ventilator-associated pneumonia (VAP) is a challenge, particularly after cardiac surgery. The use of biological markers of infection has been suggested to improve the accuracy of VAP diagnosis. We aimed to evaluate the usefulness of soluble triggering receptor expressed on myeloid cells (sTREM)-1 in the diagnosis of VAP following cardiac surgery.

Methods

This was a prospective observational cohort study of children with congenital heart disease admitted to the pediatric intensive care unit (PICU) after surgery and who remained intubated and mechanically ventilated for at least 24 hours postoperatively. VAP was defined by the 2007 Centers for Disease Control and Prevention criteria. Blood, modified bronchoalveolar lavage (mBAL) fluid and exhaled ventilator condensate (EVC) were collected daily, starting immediately after surgery until the fifth postoperative day or until extubation for measurement of sTREM-1.

Results

Thirty patients were included, 16 with VAP. Demographic variables, Pediatric Risk of Mortality (PRISM) and Risk Adjustment for Congenital Heart Surgery (RACHS)-1 scores, duration of surgery and length of cardiopulmonary bypass were not significantly diferent in patients with and without VAP. However, time on mechanical ventilation and length of stay in the PICU and in the hospital were significantly longer in the VAP group. Serum and mBAL fluid sTREM-1 concentrations were similar in both groups. In the VAP group, 12 of 16 patients had sTREM-1 detected in EVC, whereas it was undetectable in all but two patients in the non-VAP group over the study period (p = 0.0013) (sensitivity 0.75, specificity 0.86, positive predictive value 0.86, negative predictive value 0.75, positive likelihood ratio (LR) 5.25, negative LR 0.29).

Conclusion

Measurement of sTREM-1 in EVC may be useful for the diagnosis of VAP after cardiac surgery.

Effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia in children undergoing cardiac surgery

OBJECTIVE

To evaluate the effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia and ventilator-associated pneumonia (VAP) in children undergoing cardiac surgery.

DESIGN

Prospective, randomized, double-blind, placebo-controlled trial.

SETTING

Pediatric intensive care unit (PICU) at a tertiary care hospital.

PATIENTS

One hundred sixty children undergoing surgery for congenital heart disease, randomized into 2 groups: chlorhexidine (n = 87) and control (n = 73).

INTERVENTIONS

Oral hygiene with 0.12% chlorhexidine gluconate or placebo preoperatively and twice a day postoperatively until PICU discharge or death.

RESULTS

Patients in experimental and control groups had similar ages (median, 12.2 vs 10.8 months; P = .72) and risk adjustment for congenital heart surgery 1 score distribution (66% in category 1 or 2 in both groups; P = .17). The incidence of nosocomial pneumonia was 29.8% versus 24.6% (P = .46) and the incidence of VAP was 18.3% versus 15% (P = .57) in the chlorhexidine and the control group, respectively. There was no difference in intubation time (P = .34), need for reintubation (P = .37), time interval between hospitalization and nosocomial pneumonia diagnosis (P = .63), time interval between surgery and nosocomial pneumonia diagnosis (P = .10), and time on antibiotics (P = .77) and vasoactive drugs (P = .16) between groups. Median length of PICU stay (3 vs 4 days; P = .53), median length of hospital stay (12 vs 11 days; P = .67), and 28-day mortality (5.7% vs 6.8%; P = .77) were also similar in the chlorhexidine and the control group.

CONCLUSIONS

Oral hygiene with 0.12% chlorhexidine gluconate did not reduce the incidence of nosocomial pneumonia and VAP in children undergoing cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00829842 .

Diagnosis of ventilator-associated pneumonia in children in resource-limited setting: a comparative study of bronchoscopic and nonbronchoscopic methods

OBJECTIVES

To compare the available methods for the diagnosis of ventilator-associated pneumonia in intubated pediatric patients and to suggest less costly diagnostic method for developing countries.

DESIGN

Prospective study.

SETTING

Pediatric intensive care unit of a tertiary care, multidisciplinary teaching hospital located in northern India.

PATIENTS

All consecutive patients on mechanical ventilation for >48 hrs were evaluated clinically for ventilator-associated pneumonia.

INTERVENTIONS

Four diagnostic procedures (tracheal aspiration, blind bronchial sampling, blind bronchoalveolar lavage, and bronchoscopic bronchoalveolar lavage) were performed in the same sequence within 12 hrs of clinical suspicion of ventilator-associated pneumonia. The bacterial density > or =104 colony-forming units/mL in a bronchoscopic bronchoalveolar lavage sample was taken as reference standard.

MEASUREMENTS AND MAIN RESULTS

Thirty patients with 40 episodes of ventilator-associated pneumonia were included in the study. Tracheal aspirate at the cutoff of > or =105 colony-forming units/mL was found to have sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 84%, 77%, 87.5%, 73%, and 80%, respectively. For blind bronchial sampling at > or =104 colony-forming units/mL cutoff, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 88%, 82%, 88%, 83%, and 87%, respectively; the most reliable results were obtained with blind bronchoalveolar lavage at the cutoff of > or =103 cfu/mL (sensitivity 96%, specificity 80%, positive predictive value 88%, negative predictive value 92%, and accuracy 90%). The area under the receiver operating characteristic curve of tracheal aspiration, blind bronchial sampling, and blind bronchoalveolar lavage was 0.87 +/- 0.06, 0.89 +/- 0.06, and 0.89 +/- 0.05, respectively. The cost of balloon-tip pressure catheter used for blind bronchoalveolar lavage was INR 1600.00 (US$40) whereas that for blind bronchial sampling was only INR 35.00 (<1 US$).

CONCLUSIONS

Blind bronchoalveolar lavage was the most reliable method followed closely by blind bronchial sampling for the diagnosis of ventilator-associated pneumonia. Considering the difference of the cost in the two procedures, blind bronchial sampling may be the preferred method in the pediatric intensive care unit of a developing country.

Effect of age, polymicrobial disease, and maternal HIV status on treatment response and cause of severe pneumonia in South African children: a prospective descriptive study

BACKGROUND

HIV-related pneumonia is the main cause of paediatric hospital admissions in southern Africa. We aimed to measure predictors of treatment failure and the cause of non-responsive pneumonia in children admitted to hospital with severe pneumonia in Durban, South Africa.

METHODS

We investigated 358 children aged 1-59 months who presented with WHO-defined severe or very severe pneumonia. Children were recruited irrespective of HIV status and started on a standard antimicrobial regimen of benzylpenicillin and gentamicin. All infants also received high-dose trimethoprim-sulfamethoxazole. The primary outcome measure was treatment failure at 48 h.

FINDINGS

242 (68%) children were HIV infected, 41 (12%) HIV exposed, uninfected, and 75 (21%) HIV uninfected. Failure to respond by 48 h was predicted by age under 1 year (adjusted odds ratio 6.38, 95% CI 2.72-14.91, p<0.0001), very severe disease (2.47, 1.17-5.24, p=0.0181), HIV status (HIV infected 10.3, 3.26-32.51; HIV exposed, uninfected 6.02, 1.55-23.38; p=0.0003), and polymicrobial disease (one organism 2.06, 1.05-4.05; two organisms 10.75, 4.38-26.36; p<0.0001) on logistic regression analysis. All children with three organisms failed treatment. 72/110 treatment failures had at least two organisms isolated. Three of nine HIV-exposed, uninfected infants, 29/74 HIV-infected, but no HIV-uninfected infants who failed study therapy had Pneumocystis jirovecii pneumonia.

INTERPRETATION

For children younger than 1 year, the WHO guidelines are inadequate and need to be revised since both HIV-infected and HIV-exposed, uninfected infants had more treatment failures than did HIV-uninfected infants. Polymicrobial disease is an important reason for treatment failure, and we need to identify rapid low-cost diagnostic methods to assist clinicians.

Correlation of augmented IL-8 production to premature chronic lung disease: implication of posttranscriptional regulation

Despite that advances in neonatal medicine have significantly reduced the early mortality of premature infants, a considerable number of them are still prone to develop chronic lung disease (CLD) later. To find a method of early prevention, we investigated the efficacy of using certain early proinflammatory responses to predict the development of CLD. In the present study, 34 premature infants who required endotracheal intubation within 4 h of birth were recruited for analysis of IL-8, IL-10, and TNF-alpha levels in their bronchoalveolar lavage (BAL) fluid and blood. It was found that level of IL-8 but not TNF-alpha or IL-10 in initial BAL fluid was significantly correlated to neutrophils in the BAL and inversely correlated to the gestational age of prematurity. Elevation of IL-8 level in BAL on the first day of life was correlated to the development of CLD. Further studies showed that neonatal cord blood released significantly higher IL-8 but lower TNF-alpha levels after stimulation by endotoxin. The augmented IL-8 mRNA expression in cord blood was inhibited by actinomycin D but enhanced by cycloheximide, suggesting that IL-8 production is controlled by de novo transcriptional induction as well as posttranscriptional up-regulation of IL-8 by neonatal leukocytes, relating to the development of CLD. Thus, an appropriate modulation of initial IL-8 production in premature infants might be beneficial for the prevention of the development of CLD.

HLA-DP4 presents an immunodominant peptide from the RSV G protein to CD4 T cells

CD4 T cells play a crucial role during virus infections by producing antiviral cytokines and by regulating humoral and cellular immune responses. Unfortunately however, exaggerated CD4 T cell responses can cause significant immune-mediated disease as was observed during RSV infections in children previously vaccinated with a formalin-inactivated virus in the 1960s. It has been observed that vaccination with the G protein of RSV tends to prime mice for a similar Th2-mediated enhanced disease. Whether the G protein may play a role in enhanced disease in man is unclear. In the present study, we identified an immunodominant epitope in the conserved region of the G protein encompassing amino acid residues 162-175. This epitope is presented in the context of HLA-DPB1*0401 and DPB1*0402, the most prevalent HLA class II alleles. Importantly, in some patients, a mixed Th1/Th2 response against this epitope was found in bronchoalveolar lavage samples during primary RSV infections.

Non-bronchoscopic bronchoalveolar lavage in the microbiological diagnosis of pneumonia in mechanically ventilated patients

A prospective study comparing standardized non-bronchoscopic bronchoalveolar lavage (sNB-BAL) and non-specific endotracheal aspirate (NsETA) in the microbiological diagnosis of pneumonia in mechanically ventilated patients is described. One hundred episodes in 82 mechanically ventilated patients with or without radiological and clinical diagnostic criteria of pneumonia were studied. NsETA and sNB-BAL was performed on the day of study. Fifty-one patients had pneumonia (21 ventilator-associated, 12 hospital-acquired, 18 community-acquired) and 49 had no pneumonia as defined by widely accepted clinico-radiological criteria. The sNB-BAL was found to be significantly more specific (0. 73) compared to NsETA (0.35) for the microbiological diagnosis of pneumonia. Colonization rates with NsETA were significantly higher compared to sNB-BAL (P value <0.0001). No patient had complications attributable to the sNB-BAL procedure. We conlude that sNB-BAL is a safe, effective, sensitive, specific and inexpensive procedure for the serial evaluation of pneumonia in mechanically ventilated patients.

Protected specimen brush or bronchoalveolar lavage to diagnose bacterial nosocomial pneumonia in ventilated adults: a meta-analysis

OBJECTIVE

We conducted a meta-analysis by using summary receiver operating characteristic curves to compare the diagnostic value for bacterial nosocomial pneumonia of the following: a) quantitative culture (colony-forming units per milliliter or CFU/mL) of respiratory secretions collected with a bronchoscopic protected specimen brush (PSB); b) quantitative culture of a bronchoscopic bronchoalveolar lavage (BAL); and c) the percentage of infected cells (IC) in BAL.

DATA SOURCES

All studies published in the English or the French language, through January 1, 1995, on the evaluation of PSB or BAL for the diagnosis of pneumonia were considered for analysis. The relevant literature was identified through computer and reference searching and by experts in the field.

STUDY SELECTION

A study was included if at least two of three independent readers regarded its purpose as the evaluation of CFU-PSB, CFU-BAL, or IC-BAL for the diagnosis in human beings of bacterial nosocomial pneumonia in ventilated adults and if the study was prospective and published in a peer-reviewed journal.

DATA EXTRACTION

Three readers reviewed all published articles and decided whether to include each study; consensus was defined as agreement by at least two readers. The authors of each original article included in the meta-analysis were asked to complete a questionnaire in which they were asked to check and to correct the data extracted by one of the independent readers.

DATA SYNTHESIS

Summary receiver operating characteristic curves were used to compare the efficacy of three diagnostic tests. Eighteen studies on CFU-PSB (795 patients) were included, as well as 11 studies on CFU-BAL (435 patients) and 11 on IC-BAL (766 patients). The accuracy of these tests was not different. However, it seems that administration of previous antibiotics markedly decreased accuracy of CFU-PSB (p = .0002) but not the accuracy of CFU-BAL and that of IC-BAL.

CONCLUSION

Both PSB and BAL are reliable to diagnose bacterial nosocomial pneumonia. Because CFU-BAL and IC-BAL seemed more resistant to the effects of antibiotics, we recommend BAL rather than PSB if the patient is already receiving antibiotics.

Diagnosis of ventilator-associated pneumonia

The diagnosis of ventilator-associated pneumonia (VAP) is problematic despite numerous attempts at defining acceptable diagnostic criteria and the optimal technique for routine respiratory sampling. Clinical criteria have imperfect diagnostic reliability in ventilated patients, but remain crucial for defining those patients who may require respiratory sampling. Quantitative clinical scoring systems may improve the accuracy of clinical diagnosis in some ventilated patients. Review of published studies suggest that fibreoptic bronchoscopic techniques have greater diagnostic reliability than qualitative endotracheal aspirates, despite inconsistent results when comparing the same techniques in different centres. However, the cost and invasive nature of bronchoscopic methods precludes their use as first-line techniques in VAP. Non-bronchoscopic, non-directed techniques are cheaper, safer and more widely available alternatives to fibreoptic bronchoscopy techniques and have comparable accuracy. Quantitation of respiratory tract cultures is useful in excluding VAP in patients with equivocal signs of pneumonia. The diagnostic threshold of bacterial load that defines the presence of VAP should vary according to the pre-test probability of pneumonia, length of ventilation, antibiotic administration and immunocompetence of the patient.

Strategies to prevent chronic neonatal lung disease

The pathogenesis of chronic neonatal lung disease involves the combined iatrogenic insults of oxygen toxicity and barotrauma in addition to lung inflammation. Newer ventilator strategies using smaller tidal volumes (3-7 mL/kg) in order to avoid overdistension, higher positive end-respiratory pressure and lower peak inspiratory pressures decrease barotrauma. Earlier reduction of FiO2 through the use of surfactant, high frequency ventilation and nitric oxide reduce oxygen toxicity. Other measures include careful fluid balance, avoidance of prolonged paralysis and early steroids to decrease inflammation.