Blind protected specimen brush and bronchoalveolar lavage in ventilated children

Systematic Endotracheal Aspiration in the Pediatric Intensive Care Unit Reduces Broad-spectrum Antibiotic Use for Ventilator-associated Pneumonia

AIM

To determine the impact of a systematic endotracheal aspiration (ETA) sampling program for mechanically ventilated patients on initial antibiotic therapy for ventilator-acquired pneumonia (VAP).

DESIGN

Retrospective cohort study; before-after study design.

SETTING

Pediatric intensive care unit (PICU) with 16 medical and surgical beds in a tertiary teaching hospital.

SUBJECTS

Patients <16 years of age hospitalized in the PICU who fulfilled VAP criteria.

INTERVENTION

Biweekly systematic ETA sampling was conducted in mechanically ventilated patients.

MEASUREMENTS

We retrospectively studied patients who received antibiotic therapy for suspected VAP 12 months before and after the initiation of systematic ETA (periods 1 and 2, respectively), evaluating the initial antibiotic therapy spectrum in both periods.

RESULTS

During period 1, 56 patients developed VAP and 47 developed VAP during period 2. The incidence was 17 cases of VAP/1000 days of mechanical ventilation in both periods. Ideal antibiotic therapy was prescribed in 19.6% of cases for period 1 and 55.2% for period 2 (P = 0.001). Initial antibiotic therapy for VAP during period 2 had a significantly lower proportion of broad-spectrum antibiotics than therapy during period 1 (P = 0.01).

CONCLUSION

In our PICU, knowledge of bronchial colonization reduced initial broad-spectrum antibiotic use for VAP.

Ventilator-associated pneumonia in adults: a narrative review

Ventilator-associated pneumonia (VAP) is one of the most frequent ICU-acquired infections. Reported incidences vary widely from 5 to 40% depending on the setting and diagnostic criteria. VAP is associated with prolonged duration of mechanical ventilation and ICU stay. The estimated attributable mortality of VAP is around 10%, with higher mortality rates in surgical ICU patients and in patients with mid-range severity scores at admission. Microbiological confirmation of infection is strongly encouraged. Which sampling method to use is still a matter of controversy. Emerging microbiological tools will likely modify our routine approach to diagnosing and treating VAP in the next future. Prevention of VAP is based on minimizing the exposure to mechanical ventilation and encouraging early liberation. Bundles that combine multiple prevention strategies may improve outcomes, but large randomized trials are needed to confirm this. Treatment should be limited to 7 days in the vast majority of the cases. Patients should be reassessed daily to confirm ongoing suspicion of disease, antibiotics should be narrowed as soon as antibiotic susceptibility results are available, and clinicians should consider stopping antibiotics if cultures are negative.

Ventilator-associated pneumonia in neonates and children: a systematic analysis of diagnostic methods and prevention

AIM

While ventilator-associated pneumonia (VAP) remains frequent in Pediatric ICU, there is no gold standard for diagnosis.

METHODOLOGY

We conducted a systematic PUBMED analysis (January 1990-January 2017) searching original, full-length studies addressing only pediatric patients; for VAP diagnosis, only those comparing different diagnostic methods and for VAP prevention those implementing preventive measures.

RESULTS

Among 367 articles, 17 and 16 were analyzed for diagnosis and prevention, respectively. For diagnosis, 13 studies used CDC criteria; whereas, 14 assessed algorithms: clinical pulmonary index score, ventilator-associated events and biomarkers. Among five randomized trials assessing preventive strategies one found a role of probiotics. Ventilator-care bundles reduced VAP rates.

CONCLUSION

Absence of diagnostic gold standard impedes comparison of current approaches and preventive strategies.

Ventilator-Associated Pneumonia in Critically Ill Children: A New Paradigm

Ventilator-associated pneumonia (VAP) is a serious complication of critical illness. Surveillance definitions have undergone revisions for more objective and consistent reporting. The 1 organism-1 disease paradigm for microbial involvement may not adequately apply to many cases of VAP, in which pathogens are introduced to a pre-existing and often complex microbial community that facilitates or hinders the potential pathogen, consequently determining whether progression to VAP occurs. As omics technology is applied to VAP, a paradigm is emerging incorporating simultaneous assessments of microbial populations and their activity, as well as the host response, to personalize prevention and treatment.

Endotracheal Aspirate Microscopy, Cultures and Endotracheal Tube Tip Cultures for Early Prediction of Ventilator Associated Pneumonia in Neonates

OBJECTIVE

To evaluate the utility of endotracheal aspirate microscopy, culture and endotracheal tube tip culture for early diagnosis of ventilator-associated pneumonia in neonates.

METHODS

Inborn ventilated neonates were followed-up for ventilator-associated pneumonia using Center for Disease Control and Prevention (CDC) criteria. Endotracheal aspirate microscopy, culture and endotracheal tube tip cultures were performed.

RESULTS

Ventilator-associated pneumonia occurred in 28/68 (41%) neonates as per CDC criteria. Endotracheal aspirate microscopy (≥5 polymorphonuclear cells per high power field) and endotracheal aspirate culture had 78.6% and 75% sensitivity, 87.5% and 90% specificity, positive predictive value of 81.5% and 84%, and negative predictive value of 85.4% and 83.72%, respectively. Mean (SD) time of result of microscopy and endotracheal aspirate culture was 55.7 (4.3) h and 108.3 (19.7) h, respectively in comparison to diagnosis made at 143.5 (23.3) h, as per CDC criteria.

CONCLUSION

Endotracheal aspirate microscopic examination and culture can be supportive in objective diagnosis of ventilator-associated pneumonia with an added advantage of earlier prediction.

Ventilator Associated Pneumonia in Children

Ventilator associated pneumonia (VAP) is a common complication in mechanically ventilated children and adults. There remains much controversy in the literature over the definition, treatment and prevention of VAP. The incidence of VAP is variable, depending on the definition used and can effect up to 12% of ventilated children. For the prevention and reduction of the incidence of VAP, ventilation care bundles are suggested, which include vigorous hand hygiene, head elevation and use of non-invasive ventilation strategies. Diagnosis is mainly based on the clinical presentation with a lung infection occurring after 48hours of mechanical ventilation requiring a change in ventilator settings (mainly increased oxygen requirement, a positive culture of a specimen taken preferentially using a sterile sampling technique either using a bronchoscope or a blind lavage of the airways). A new infiltrate on a chest X ray supports the diagnosis of VAP. For the treatment of VAP, initial broad-spectrum antibiotics should be used followed by a specific antibiotic therapy with a narrow target once the bacterium is confirmed.

Comparison of the New Adult Ventilator-Associated Event Criteria to the Centers for Disease Control and Prevention Pediatric Ventilator-Associated Pneumonia Definition (PNU2) in a Population of Pediatric Traumatic Brain Injury Patients

OBJECTIVES

The new Centers for Disease Control and Prevention paradigm for ventilator-associated events is intended to simplify surveillance of infectious and noninfectious complications of mechanical ventilation in adults. We assessed the ventilator-associated events algorithm in pediatric patients.

DESIGN

A retrospective observational cohort study.

SETTING

This single-center study took place in a PICU at an urban academic medical facility.

PATIENTS

Pediatric (ages 0-18 yr old) trauma patients with moderate-to-severe traumatic brain injury ventilated for greater than or equal to 2 days.

MEASUREMENTS AND MAIN RESULTS

We assessed for pediatric ventilator-associated pneumonia (as defined by current Centers for Disease Control and Prevention PNU2 guidelines), adult ventilator-associated events, and an experimental ventilator-associated events definition modified for pediatric patients. We compared ventilator-associated events to ventilator-associated pneumonia to calculate the test characteristics. Thirty-nine of 119 patients (33%) developed ventilator-associated pneumonia. Sensitivity of the adult ventilator-associated condition definition was 23% (95% CI, 11-39%), which increased to 56% (95% CI, 40-72%) using the modified pediatric ventilator-associated pneumonia criterion. Specificity reached 100% for both original and modified pediatric probable ventilator-associated pneumonia using ventilator-associated events criteria. Children who developed ventilator-associated pneumonia or ventilator-associated condition had similar baseline characteristics: age, mechanism of injury, injury severity scores, and use of an intracranial pressure monitor. Diagnosis of ventilator-associated pneumonia and ventilator-associated condition portended similarly unfavorable outcomes: longer median duration of ventilation, ICU and hospital length of stay, and more discharges to rehabilitation, home health, or nursing care compared with patients with no pulmonary complication.

CONCLUSIONS

Both current and modified ventilator-associated events criteria have poor sensitivity but good specificity in identifying pediatric ventilator-associated pneumonia. Despite poor sensitivity, the high specificity of the ventilator-associated events diagnoses does provide a useful and objective metric for interinstitution ICU comparison. Ventilator-associated pneumonia and ventilator-associated condition were both associated with excess morbidity in pediatric traumatic brain injury patients.

Ventilator-Associated Pneumonia in Pediatric Traumatic Brain Injury

Ventilator-associated pneumonia (VAP) is a common occurrence among intubated pediatric traumatic brain injury (TBI) patients. However, little is known about the epidemiology, risk factors, and microbiology of VAP in pediatric TBI. We reviewed a cohort of 119 pediatric moderate-to-severe TBI patients and identified 42 with VAP by positive protected bronchial brush specimens. Location of intubation, severity of injury, and antibiotic administration within 2 days after injury were not associated with VAP. Most treatments for elevated intracranial pressure were associated with increased risk of VAP; however, in a multi-variable analysis barbiturate coma (hazard ratio [HR], 3.2; 95% confidence interval [CI] 1.4-7.3), neuromuscular blockade (NMBA; HR, 3.4; 95% CI 1.6-7.3), and use of a cooling blanket for euthermia (HR 2.4; 95% CI 1.1-5.5) remained independently associated with VAP. Most VAP (55%) occurred prior to hospital Day 4 and only 7% developed VAP after Day 7. Methicillin-sensitive Staphylococcus aureus (34%), Haemophilus influenzae (22%), and Streptococcus pneumoniae (15%) were the most common organisms, comprising 71% of isolated pathogens (36% of infections were polymicrobial). Patients with VAP had significantly longer intensive care unit and hospital stays, as well as increased risk of chronic care needs after discharge, but not mortality. VAP is a common occurrence in pediatric TBI patients, and early empiric therapy for patients requiring barbiturate infusion, NMBA, or use of a cooling blanket could mitigate morbidity.

Diagnosis of bacterial ventilator-associated pneumonia in children: reproducibility of blind bronchial sampling

OBJECTIVE

To evaluate the reproducibility of blind bronchial sampling in patients with suspected diagnosis of bacterial ventilator-associated pneumonia.

DESIGN

Prospective study.

SETTING

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

PATIENTS

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

INTERVENTIONS

Children with clinical ventilator-associated pneumonia were subjected to blind bronchial sampling twice.

MEASUREMENTS AND MAIN RESULTS

Sixty-eight blind bronchial sampling samples from 34 patients were analyzed for polymorphonuclear cells, the presence, type, and number of bacteria. Acinetobacter baumannii was the most common organism grown from distal respiratory secretions. For polymorphonuclear cells, the concordance between two blind bronchial samples was 85.3% and kappa coefficient was 0.65. The concordance for the presence and type of bacteria in Gram staining in two samples was 85.3% and kappa coefficient was 0.68. The intraclass coefficients for bacterial index and predominant species index were 0.82 (95% confidence interval 0.65-0.91) and 0.89 (95% confidence interval 0.78-0.94), respectively. The use of prior antibiotics did not adversely affect the reproducibility of blind bronchial sampling. No major complications were recorded during the procedure.

CONCLUSIONS

Blind bronchial sampling of lower respiratory tract secretions in mechanically ventilated patients generates reproducible results of quantitative and qualitative cultures. We suggest that blind bronchial sampling may provide valuable clue to the bacterial etiology in ventilated child with suspected clinical ventilator-associated pneumonia.

Ventilator-associated pneumonia in newborn infants diagnosed with an invasive bronchoalveolar lavage technique: a prospective observational study

OBJECTIVES

To establish the incidence, etiology, risk factors, and outcomes associated with ventilator-associated pneumonia using an invasive sampling technique to avoid contamination.

PATIENTS

Eligible patients were intubated neonates treated with mechanical ventilation who followed the criteria of the Centers for Disease Control and Prevention/National Nosocomial Infection Surveillance. Bronchoalveolar lavage samples were collected using a blind-protected catheter to avoid contamination of upper respiratory microorganisms. Isolation of >10(3) colony-forming unit/mL was required for diagnosis.

MEASUREMENTS AND MAIN RESULTS

In 198 neonates intubated for >48 hrs, a total of 18 episodes of ventilator-associated pneumonia in 16 infants representing a prevalence of 8.1 were diagnosed. The pooled mean ventilator-associated pneumonia rate was 10.9/1,000 ventilator days. The mean age at diagnosis of ventilator-associated pneumonia was 29 ± 15 days after a mean of 21 ± 16 days of mechanical ventilation. Gram-negative bacteria were the most commonly isolated pathogens and Pseudomonas aeruginosa was the most frequent causative agent. Hospital length of stay was significantly longer for ventilator-associated pneumonia patients; however, no significant differences in mortality were found. Univariate analysis comparing patients with and without ventilator-associated pneumonia showed that days of mechanical ventilation, days of oxygen, number of reintubations, number of transfusions, bloodstream infection, and enteral feeding were all significantly associated with ventilator-associated pneumonia. However, in multivariate analysis the unique independent risk factor was days of mechanical ventilation (odds ratio 1.12, confidence interval 95% 1.07-1.17).

CONCLUSIONS

Ventilator-associated pneumonia is a frequent nosocomial infection in newborns. Only duration of mechanical ventilation has been identified as an independent risk factor for ventilator-associated pneumonia. The use of a blind invasive sampling technique seems to diminish sample contamination.

Investigation into the effect of closed-system suctioning on the frequency of pediatric ventilator-associated pneumonia in a developing country

OBJECTIVE

To investigate the effect of closed-system vs. open endotracheal suctioning on the frequency of ventilator-associated pneumonia and outcome in a pediatric intensive care unit in a developing country.

DESIGN

Prospective observational and nonrandomized controlled clinical study.

SETTING

A 20-bed pediatric intensive care unit in a tertiary pediatric hospital.

PATIENTS

Infants and children mechanically ventilated for >24 hrs.

INTERVENTION

: Pediatric intensive care unit suctioning systems were alternated monthly. An 8-month interim analysis was planned with a priori efficacy and futility study termination boundaries set at p < .006 and p > .52, respectively.

MEASUREMENTS AND MAIN RESULTS

Demographic, clinical, and laboratory data were prospectively recorded. Ventilator-associated pneumonia was diagnosed using the Clinical Pulmonary Infection Score, and the results were confirmed retrospectively using Centers for Disease Control criteria. A total of 250 patients (median [interquartile range] age of 3.8 [1.2-15.0] months) in 263 pediatric intensive care unit admissions were included. Fifty-nine admissions developed ventilator-associated pneumonia, with a calculated rate of 45.1 infections per 1000 ventilated days. There was no difference in characteristics or outcome between patients on closed-system suctioning (n = 83) and those on open endotracheal suctioning (n = 180). The frequencies of ventilator-associated pneumonia for patients on closed-system suctioning and open endotracheal suctioning were 20.5% and 23.3%, respectively (p = .6), reaching the a priori set limit of futility. Patients who developed ventilator-associated pneumonia spent a median (interquartile range) of 22 (13-37) and 11 (8-16) days in the hospital and pediatric intensive care unit, respectively, compared to 14.5 (10-24) and 6 (4-8) days for those without ventilator-associated pneumonia (p < .001). A 22% proportion of patients who developed ventilator-associated pneumonia died compared to 11.3% of those without ventilator-associated pneumonia (p = .03). Risk factors for ventilator-associated pneumonia identified on multiple logistic regression were duration of mechanical ventilation, transport out of the pediatric intensive care unit, and blood transfusion.

CONCLUSION

Closed-system suctioning did not affect the frequency of ventilator-associated pneumonia or patient outcome in this setting.

The management of community-acquired pneumonia in infants and children older than 3 months of age: clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America

Evidenced-based guidelines for management of infants and children with community-acquired pneumonia (CAP) were prepared by an expert panel comprising clinicians and investigators representing community pediatrics, public health, and the pediatric specialties of critical care, emergency medicine, hospital medicine, infectious diseases, pulmonology, and surgery. These guidelines are intended for use by primary care and subspecialty providers responsible for the management of otherwise healthy infants and children with CAP in both outpatient and inpatient settings. Site-of-care management, diagnosis, antimicrobial and adjunctive surgical therapy, and prevention are discussed. Areas that warrant future investigations are also highlighted.

Opportunities for antibiotic reduction in mechanically ventilated children

OBJECTIVE

To identify opportunities to safely reduce antibiotic use in critically ill children with moderately severe respiratory failure.

DESIGN

Prospective observational.

SETTING

Four pediatric intensive care units at three American tertiary care children's hospitals.

PATIENTS

Children aged 2 months to 18 yrs who were mechanically ventilated, had an abnormal chest radiograph, and for whom the attending physicians had initiated antibiotics for presumed bacterial pneumonia.

INTERVENTION

Nonbronchoscopic bronchoalveolar lavage.

METHODS AND MAIN RESULTS

Eligible children were subjected to nonbronchoscopic bronchoalveolar lavage within 12 hrs of initiating antibiotics. The concentration of bacteria in the lavage fluid was determined by quantitative assay, and the diagnosis of pneumonia was confirmed if >10 (4)pathogenic bacteria/mL were cultivated. Twenty-one subjects were enrolled, in whom 20 nonbronchoscopic bronchoalveolar lavage procedures were completed. Six of 20 subjects had nonbronchoscopic bronchoalveolar lavage results confirmatory of bacterial pneumonia, three additional subjects had bacteria isolated at concentrations below levels conventionally used to diagnose bacterial pneumonia, and the remaining 11 demonstrated no growth. Clinical parameters reflective of severity of disease and laboratory parameters reflective of systemic and local inflammation were tested for their association with a positive nonbronchoscopic bronchoalveolar lavage, but none was demonstrated.

CONCLUSIONS

Eleven of 20 mechanically ventilated children treated with antibiotics for presumed infectious pneumonia had undetectable concentrations of bacteria in their lower respiratory tract, and three others had organisms present at low concentrations, suggesting that opportunities exist to reduce antibiotic exposure in this population.

The diagnostic dilemma of ventilator-associated pneumonia in critically ill children

OBJECTIVE

A review of the existing literature on ventilator-associated pneumonia in children with emphasis on problems in diagnosis.

DATA SOURCES

A systematic literature review from 1947 to 2010 using Ovid MEDLINE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Science using key words "ventilator associated pneumonia" and "children." Where pediatric data were lacking, appropriate adult studies were reviewed and similarly referenced.

STUDY SELECTION

Two hundred sixty-two pediatric articles were reviewed and data from 48 studies selected. Data from 61 adult articles were also included in this review.

DATA EXTRACTION AND SYNTHESIS

Ventilator-associated pneumonia is the second most common nosocomial infection and the most common reason for antibiotic use in the pediatric intensive care unit. Attributable mortality is uncertain but ventilator-associated pneumonia is associated with significant morbidity and cost. Diagnosis is problematic in that clinical, radiologic, and microbiologic criteria lack sensitivity and specificity relative to autopsy histopathology and culture. Qualitative tracheal aspirate cultures are commonly used in diagnosis but lack specificity. Quantitative tracheal aspirate cultures have sensitivity (31-69%) and specificity (55-100%) comparable to bronchoalveolar lavage (11-90% and 43-100%, respectively) but concordance for the same bacterial species when compared with autopsy lung culture was better for bronchoalveolar lavage (52-90% vs. 50-76% for quantitative tracheal aspirate). Staphylococcus aureus and Pseudomonas species are the most common organisms, but microbiologic flora change over time and with antibiotic use. Initial antibiotics should offer broad-spectrum coverage but should be narrowed as clinical response and cultures dictate.

CONCLUSIONS

Ventilator-associated pneumonia is an important nosocomial infection in the pediatric intensive care unit. Conclusions regarding epidemiology, treatment, and outcomes are greatly hampered by the inadequacies of current diagnostic methods. We recommend a more rigorous approach to diagnosis by using the Centers for Disease Control and Prevention algorithm. Given that ventilator-associated pneumonia is the most common reason for antibiotic use in the pediatric intensive care unit, more systematic studies are sorely needed.

Health Care–Associated Infection in the Pediatric Intensive Care Unit

•Handwashing is the most important means of preventing nosocomial infection. Each pediatric intensive care unit should develop programs to increase compliance with hand hygiene. •Nonessential invasive devices should be removed. Establish routines that require individual patient evaluation of device use daily. •Antimicrobial stewardship aims to minimize overexposure and unnecessary use of broad-spectrum antibiotics. Antibiotic-resistant bacteria are an increasing concern as a cause of hospital-acquired infection, requiring a multipronged approach to control that includes adherence to isolation procedures, appropriate use of antibiotics, educational interventions, prescribing guidelines, and restriction of the use of some antibiotics. •A comprehensive infection prevention and control program allied with organizational quality and patient safety programs is an essential strategy for minimizing hospital-acquired infections. Critical care teams should establish strong collaborative partnerships with the infection prevention and control service. •Parents and visitors should be made partners of the infection control team to help prevent infection in their children.

Usefulness of Gram staining of tracheal aspirates in initial therapy for ventilator-associated pneumonia in extremely preterm neonates

OBJECTIVE

To determine the effectiveness of Gram staining of tracheal aspirates for predicting causative microorganisms and guiding appropriate initial antibiotic therapy to treat ventilator-associated pneumonia (VAP) in extremely preterm neonates.

STUDY DESIGN

A prospective study was conducted on all episodes of presumed VAP in neonates with a gestational age below 28 weeks at birth.

RESULT

Gram-positive cocci and Gram-negative bacilli were the causative microorganisms in 11 and 38 confirmed episodes of VAP, respectively. The sensitivity and specificity of Gram staining were 82 and 100% for Gram-positive VAP and 100 and 82% for Gram-negative VAP, respectively. The initial antibiotic therapies based on Gram-stain findings were appropriate for 96% (47/49) of patients with VAP.

CONCLUSION

Gram staining of tracheal aspirates is useful in predicting classes of causative microorganisms and for guiding appropriate initial antibiotic therapy for VAP in extremely preterm neonates.

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.

Death by acid rain: VAP or EXIT?

Ventilator-associated pneumonia (VAP) is a new (nosocomial) lower respiratory tract infection diagnosed in mechanically ventilated patients 48 or more hours after intubation. There is no gold standard for establishing the diagnosis and its pathogenesis is iatrogenic and multifactorial. Gastro-oesophageal reflux is common in mechanically ventilated children, but its role in VAP remains speculative. VAP is associated with increased mortality and morbidity, prolonged duration of ventilation and hospital stay, and escalated costs of hospitalisation. VAP 'bundles' are championed as the antidote.

High viral frequency in children with gastroesophageal reflux-related chronic respiratory disorders

INTRODUCTION

In the pediatric population chronic respiratory disorders (CRDs) include many pathological entities in which gastroesophageal reflux (GER) may play a role in the induction or persistence of clinical symptoms. It is not well established whether infective agents may be present in lung aspiration. The aim of the work was to investigate whether different infective agents could be found in children with GER-related CRDs.

MATERIALS AND METHODS

Extensive microbiological investigations including culture for bacterial agents, serology, direct fluorescent antigen and polymerase chain reaction analyses for different respiratory viruses were performed in 32 children (18 males, 14 females, mean age 5.0 +/- 2.4 years). Fifteen children out of 32 considered as "aspirators" (lipid-laden macrophage index-LLMI->or=86 and pathological pH-assay) were compared to 17 "non-aspirators" (LLMI < 86 and normal pH-assay).

RESULTS

Aspirators were older (6.0 +/- 1.9 vs. 4.2 +/- 2.5 years, P = 0.006) and less frequently atopic (13% vs. 59%, P = 0.01) than non-aspirators. A high frequency of viral infections (20/32, 62.5%) was found, with frequent occurrence of multiple infections (10/20, 50%). Aspirators showed more frequent viral infections than non-aspirators (87% vs. 41%, P = 0.01). Rhinovirus and respiratory syncytial virus were the principal detected viruses in the aspirator group.

CONCLUSIONS

Viral infections could play a key role in the pathogenesis of GER-related CRDs.

Comparison of atopic and nonatopic children with chronic cough: bronchoalveolar lavage cell profile

Chronic cough is a common complaint in children and its relationship with asthma is controversial. The aim of the present study was to determine the pattern of airway inflammation in atopic and nonatopic children with chronic cough, and to investigate whether atopy is a predictive factor for eosinophilic inflammation in cough. Bronchoalveolar lavage (BAL; three aliquots of 1 ml/kg saline) was performed in the right middle lobe of 24 (11 atopic and 13 nonatopic) children with persistent cough (8 females, 16 males), mean age 4.7 years (range: 1-11). Atopy was defined as an elevated total serum IgE or a positive RAST test. Both atopic and nonatopic children with persistent cough had an increase in total cells/ml in BAL (atopic: median 39 x 10(4), range: 20-123; nonatopic: median 22 x 10(4), range: 17-132) compared to nonatopic controls (median 11 x 10(4), range 9-30). The increases were mainly in neutrophils (atopic: median 17%, range 2.5-88.5%; nonatopic: median 6%, range 1.0-55.0%) compared to controls (median 1.55%, range 0.5-7.0%; atopics vs. controls, P < 0.005). There were no significant increases in eosinophils, lymphocytes, epithelial cells, or mast cells. Eosinophils were elevated in only 5/11 atopic and none of the nonatopic children. The increased percentage of neutrophils in the BAL fluid of atopic and nonatopic children with persistent cough could be due to an underlying inflammatory process driving the cough, or even conceivably, due to the effect of coughing itself. In this highly selected series, the absence of eosinophilic inflammation in the majority suggests that most would be predicted not to respond to inhaled corticosteroid therapy. This study underscores the need to be cautious about treating coughing children with inhaled corticosteroids, even in the context of a tertiary referral practice.

Ventilator-associated pneumonia in neonatal and pediatric intensive care unit patients

Ventilator-associated pneumonia (VAP) is the second most common hospital-acquired infection among pediatric intensive care unit (ICU) patients. Empiric therapy for VAP accounts for approximately 50% of antibiotic use in pediatric ICUs. VAP is associated with an excess of 3 days of mechanical ventilation among pediatric cardiothoracic surgery patients. The attributable mortality and excess length of ICU stay for patients with VAP have not been defined in matched case control studies. VAP is associated with an estimated $30,000 in attributable cost. Surveillance for VAP is complex and usually performed using clinical definitions established by the CDC. Invasive testing via bronchoalveolar lavage increases the sensitivity and specificity of the diagnosis. The pathogenesis in children is poorly understood, but several prospective cohort studies suggest that aspiration and immunodeficiency are risk factors. Educational interventions and efforts to improve adherence to hand hygiene for children have been associated with decreased VAP rates. Studies of antibiotic cycling in pediatric patients have not consistently shown this measure to prevent colonization with multidrug-resistant gram-negative rods. More consistent and precise approaches to the diagnosis of pediatric VAP are needed to better define the attributable morbidity and mortality, pathophysiology, and appropriate interventions to prevent this disease.

Microbiological diagnostic procedures in respiratory infections: suppurative lung disease

Pursuing a microbiological diagnosis in suppurative lung disease can enable focused antibiotic therapy, identify pathogens of potential concern for infection control, and in some cases delineate a specific pathological process. Suppurative lung disease can be categorized as acute or chronic. Acute disease most commonly consists of lung abscess or parapneumonic empyema. The vast majority of chronic suppurative lung disease in childhood is due to cystic fibrosis. Samples from the respiratory tract offer the most useful information for diagnosis and management, but adjunctive information can also be obtained from serological methods, blood cultures and molecular techniques. The quality of respiratory tract samples is vital to aid accurate interpretation of results, and this varies according to the technique of collection. Antibiotic sensitivity testing is of particular importance in an era of evolving antibiotic resistance and can be problematical in cystic fibrosis.

Reduced toll-like receptor 4 and substance P gene expression is associated with airway bacterial colonization in children

Neuro-immune interactions are increasingly relevant to human health and disease. The neuropeptide Substance P also has antibacterial activity and bears similarities to the innate immune antibacterial defensins. This suggests possible co-regulation of neuropeptide and innate immune mediators. In this study, non-bronchoscopic bronchoalveolar lavage (BAL) was performed on 69 children. BAL was examined for cellular profile, microbiology (bacteria, virus) and gene expression for TLRs 2, 3, 4; chemokine receptors (CCR3, CCR5, CXCR1); neurotrophins and neurokinin genes (TAC1, TAC3, CGRP, NGF). In children with bacterial colonization (n=10) there was an airway inflammatory response with increased BAL neutrophils, IL-8 protein, and CXCR1 expression. Substance P (TAC1) and TLR4 RNA expression were reduced in children with bacterial colonization. TLR3 mRNA was increased in 7.2% (n=5) children with rhinovirus, and there was a non-significant trend to increased TLR2. There is evidence for co-regulation of neurokinin (TAC1) and TLR4 gene expression in airway cells from children with airway bacterial colonization and their reduced expression may be associated with an impaired bacterial clearance.

Nosocomial infections in the pediatric intensive care unit: affecting the impact on safety and outcome

OBJECTIVE

To define the most common types of nosocomial infections in critically ill children and to summarize the effect of methods to reduce their prevalence.

DESIGN

Review of published literature.

RESULTS

While in the pediatric intensive care unit, 16% of children develop a nosocomial infection. Processes affecting modifiable factors of care can reduce the prevalence of hospital-acquired infections.

CONCLUSIONS

The occurrence of a nosocomial infection represents failure and is not an acceptable outcome of treating critically ill children. Evidence-based process improvement can lead to significant reductions in hospital-acquired infections in children. Most of the processes and practices discussed are not novel or intriguing but, when performed routinely and appropriately, can lead to reductions in hospital-acquired infections.

A bronchoscopic scoring system for airway secretions--airway cellularity and microbiological validation

There is currently no validated scoring system for quantification of airway secretions in children. A user friendly, valid scoring system of airway secretions during flexible bronchoscopy (FB) would be useful for comparative purposes in clinical medicine and research. The objective of this study was to validate our bronchoscopic secretion (BS) scoring system by examining the relationship between the amount of secretions seen at bronchoscopy with airway cellularity and microbiology. In 106 children undergoing FB, the relationship of BS grades with bronchocalveolar lavage (BAL) cellularity and infective state (bacterial and viral infections) were examined using receptor operator curves (ROC). BAL was obtained according to European Respiratory Society guidelines; first lavage for microbiology and second lavage for cellularity. Area under the ROC was significant for total cell count (TCC) and neutrophil % but not for lymphocyte %. BS grade significantly related to infection positive state (chi(trend) (2) = 5.85, P = 0.016). The area under the ROC for infection positive state versus BS grade was 0.645, 95% CI 0.527-0.763. The BS scoring system is a valid method for quantifying airway secretions in children undergoing bronchoscopy. The system related well to airway cellularity and neutrophilia, as well as to an airway infective state. However, the system is only complementary to cell counts and cultures and cannot replace these laboratory quantification techniques.

Ventilator-Associated Pneumonia in Children

The purpose of this report is to review the current knowledge base related to the epidemiology, microbiology, diagnosis, and morbidity and mortality of ventilator-associated pneumonia and to review strategies to reduce the risk of acquiring this condition. Published guidelines are based largely on data from adult populations, and implications for the pediatric population must be extrapolated to a great extent. Some interventions, including elevation of the head of the bed for most patients and deep vein thrombosis prophylaxis in older pediatric patients, seem reasonable based on available literature. The use of daily sedation holidays must be weighed against the risk of inadvertent extubation. The routine use of stress ulcer prophylaxis in the pediatric population cannot be supported by the current literature.

Cough and reflux esophagitis in children: their co-existence and airway cellularity

BACKGROUND

There are no prospective studies that have examined for chronic cough in children without lung disease but with gastroesophageal reflux (GER). In otherwise healthy children undergoing flexible upper gastrointestinal endoscopy (esophago-gastroscopy), the aims of the study were to (1) define the frequency of cough in relation to symptoms of GER, (2) examine if children with cough and reflux esophagitis (RE) have different airway cellularity and microbiology in bronchoalveolar lavage (BAL) when compared to those without.

METHODS

Data specific for chronic cough (> 4-weeks), symptoms of GER and cough severity were collected. Children aged < 16-years (n = 150) were defined as 'coughers' (C+) if a history of cough in association with their GER symptoms was elicited before BAL were obtained during elective esophago-gastroscopy. Presence of esophagitis on esophageal biopsies was considered reflux esophagitis positive (E+).

RESULTS

C+ (n = 69) were just as likely as C- (n = 81) to have esophagitis, odds ratio 0.87 (95%CI 0.46, 1.7). Median neutrophil percentage in BAL was significantly different between groups; highest in C+E- (7, IQR 28) and lowest in C-E+ (5, IQR 6). BAL positive bacterial culture occurred in 20.7% and were more likely present in current coughers (OR 3.37, 95%CI 1.39, 8.08). Airway neutrophilia (median 20%, IQR 34) was significantly higher in those with BAL positive bacterial cultures than those without (5%, 4; p = 0.0001).

CONCLUSION

In children without lung disease, the common co-existence of cough with symptoms of GER is independent of the occurrence of esophagitis. Airway neutrophilia when present in these children is more likely to be related to airway bacterial infection and not to esophagitis.

Pneumonia in hospitalized children

Pneumonia is one of the most common infections in the pediatric age group and one of the leading diagnoses that results in overnight hospital admission for children. Various micro-organisms can cause pneumonia, and etiologies differ by age. Clinical manifestations vary, and diagnostic testing is frequently not standardized. Hospital management should emphasize timely diagnosis and prompt initiation of antimicrobial therapy when appropriate. Issues of particular relevance to inpatient management are emphasized in this article.

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

BACKGROUND

Gastroesophageal reflux disease (GORD) can cause respiratory disease in children from recurrent aspiration of gastric contents. GORD can be defined in several ways and one of the most common method is presence of reflux oesophagitis. In children with GORD and respiratory disease, airway neutrophilia has been described. However, there are no prospective studies that have examined airway cellularity in children with GORD but without respiratory disease. The aims of the study were to compare (1) BAL cellularity and lipid laden macrophage index (LLMI) and, (2) microbiology of BAL and gastric juices of children with GORD (G+) to those without (G-).

METHODS

In 150 children aged < 14-years, gastric aspirates and bronchoscopic airway lavage (BAL) were obtained during elective flexible upper endoscopy. GORD was defined as presence of reflux oesophagitis on distal oesophageal biopsies.

RESULTS

BAL neutrophil% in G- group (n = 63) was marginally but significantly higher than that in the G+ group (n = 77), (median of 7.5 and 5 respectively, p = 0.002). Lipid laden macrophage index (LLMI), BAL percentages of lymphocyte, eosinophil and macrophage were similar between groups. Viral studies were negative in all, bacterial cultures positive in 20.7% of BALs and in 5.3% of gastric aspirates. BAL cultures did not reflect gastric aspirate cultures in all but one child.

CONCLUSION

In children without respiratory disease, GORD defined by presence of reflux oesophagitis, is not associated with BAL cellular profile or LLMI abnormality. Abnormal microbiology of the airways, when present, is not related to reflux oesophagitis and does not reflect that of gastric juices.

Defining pneumonia in critically ill infants and children

OBJECTIVE

To define pneumonia in critically ill children in the intensive care unit setting for surveillance of infection and for the design, conduct, and evaluation of clinical trials in the prevention and therapy of lower respiratory tract infections in this population.

DESIGN

Summary of the literature with review and consensus by experts in the field.

RESULTS

A variety of diagnostic criteria from the medical literature, professional societies, and governmental health agencies and regulators were identified. Very few of these diagnostic criteria have been validated for use in children. We propose definitions for definite, possible, and probable pneumonia that build on identified definitions in the literature and use combinations of symptoms, signs, and laboratory criteria. Gaps in knowledge were identified.

CONCLUSIONS

Although pneumonia is one of the most common diagnoses in critically ill children, there have been few studies validating diagnostic criteria. Definitions for definite, probable, and possible community-acquired pneumonia and nosocomial pneumonia were achieved by consensus of experts based on guidelines from governmental agencies, professional organizations, and published literature. Future research should determine the utility of these definitions in the critically ill child and adapt them accordingly.

Concurrent bacterial infection and prolonged mechanical ventilation in infants with respiratory syncytial virus lower respiratory tract disease

OBJECTIVE

To identify demographic, clinical, and laboratory variables predictive for a concurrent bacterial pulmonary infection in ventilated infants with respiratory syncytial virus (RSV) lower respiratory tract disease (LRTD) and investigate antimicrobial drug use.

DESIGN AND SETTING

Retrospective, observational study in a 14-bed pediatric intensive care unit.

PATIENTS

82 infants younger than 1 year of age with a virologically confirmed RSV LRTD during 1996-2001, of whom 65 were mechanically ventilated.

RESULTS

Microbiological data were available from 38 ventilated infants, 10 of whom had a positive blood culture (n=1) or endotracheal aspirate (n=9) obtained upon admission to the pediatric intensive care unit (PICU). Infants with a positive culture had a lower mean gestational age but were otherwise demographically comparable to those with negative culture results. Infants with a positive culture were ventilated 4 days longer. Indicators for a concurrent bacterial infection were comparable between ventilated and nonventilated infants. Antimicrobial drugs were used in 95.1% of infants (100% of ventilated infants) with a mean duration of 7.8+/-0.3 days. The moment of initiation and duration of antimicrobial drug treatment varied considerably.

CONCLUSIONS

We observed in ventilated infants a low occurrence of concurrent bacterial pulmonary infection, but infants with positive cultures needed prolonged ventilatory support. Improvement in the diagnosis of a pulmonary bacterial infection is warranted to reduce the overuse of antimicrobial drugs among ventilated infants with RSV LRTD and to restrict these drugs to the proper patients.

Ventilator-associated pneumonia in intubated children: comparison of different diagnostic methods

OBJECTIVES

To compare different methods for diagnosis of ventilator-associated pneumonia in intubated children.

DESIGN

Prospective epidemiologic study.

SETTING

Pediatric intensive care unit of a tertiary care university hospital.

PATIENTS

All consecutive pediatric intensive care unit patients <18 yrs of age with suspected ventilator-associated pneumonia.

INTERVENTIONS

For all patients, the following diagnostic methods were compared: 1) clinical data using Centers for Disease Control criteria; 2) blind protected bronchoalveolar lavage, evaluating quantitative cultures, bacterial index of >5, Gram stain, and presence of intracellular bacteria; and 3) nonquantitative cultures of endotracheal secretions. The reference standard used was clinical judgment of three independent experts (Delphi method) who retrospectively established by consensus the presence of ventilator-associated pneumonia based on clinical, microbiological, and radiologic data. Concordance between each diagnostic method and the reference standard was evaluated by concordance percentage and kappa score. Validity was evaluated using sensitivity, specificity, positive predictive value, negative predictive value, and global value.

RESULTS

A total of 30 patients were included in the study. According to the reference standard, ventilator-associated pneumonia occurred in 10 of 30 patients (33%). Bacterial index of >5 in bronchoalveolar secretions showed the best concordance compared with the reference standard (concordance, 83%; kappa, 0.61). Bacterial index of >5 also showed the best validity (sensitivity, 78%; specificity, 86%; positive predictive value, 70%; negative predictive value, 90%; global value, 90%). Intracellular bacteria and Gram stain from bronchoalveolar secretions were very specific (95% and 81%, respectively) but not sensitive (30% and 50%, respectively). Clinical criteria and endotracheal cultures were very sensitive (100% and 90%, respectively) but poorly specific (15% and 40%, respectively).

CONCLUSION

Our data show that the most reliable diagnostic method for ventilator-associated pneumonia is a bacterial index of >5, using blind protected bronchoalveolar lavage. Further studies should evaluate the validity of all these methods according to the gold standard (autopsy).

Nosocomial pneumonia in pediatric patients: practical problems and rational solutions

Nosocomial pneumonia is a common hospital-acquired infection in children, and is often fatal. Risk factors for nosocomial pneumonia include admission to an intensive care unit, intubation, burns, surgery, and underlying chronic illness. Viruses, predominantly respiratory syncytial virus (RSV), are the most common cause of pediatric nosocomial respiratory tract infections. Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) are the predominant bacterial pathogens, and are associated with a high mortality rate. Staphylococcus aureus and Staphylococcus epidermidis are the most common Gram-positive bacteria causing nosocomial pneumonia; infections with these organisms have a better outcome than those with Gram-negative organisms. An increasing problem is the emergence of multiresistant Gram-positive and Gram-negative nosocomial pathogens. Distinguishing nosocomial pneumonia from other pulmonary processes may be difficult; diagnosis is based on clinical signs, radiological findings, and microbiological results. Recommended empiric therapy should consider factors such as the time of onset of illness, severity of disease, and specific risk factors for nosocomial pneumonia, including use of mechanical ventilation, underlying disease, or recent use of antibacterials. The resident local hospital flora should be considered when selecting therapy for nosocomial pneumonia. Early initiation of appropriate empiric therapy reduces morbidity and mortality. For empiric treatment of bacterial nosocomial pneumonia, an intravenous antibacterial regimen that includes coverage of Gram-negative bacilli and Gram-positive organisms should be used. A carbapenem or ureidopenicillin derivative (piperacillin) plus a beta-lactamase inhibitor should be used where extended spectrum beta-lactamase-producing Enterobacteriaceae are endemic. Therapy should be modified when a specific pathogen and its antimicrobial susceptibility are identified. Effective prevention of nosocomial pneumonia requires infection control measures that affect the environment, personnel, and patients. Of these, hand hygiene, appropriate infection control policies, and judicious use of antibacterials are essential.

Reproducibility of blind protected bronchoalveolar lavage in mechanically ventilated children

Blind protected bronchoalveolar lavage (BAL) could be an interesting tool in the diagnosis of ventilator-associated pneumonia in intubated children, but its reproducibility has never been evaluated. This study evaluates the reproducibility, feasibility, and safety of blind protected BAL in mechanically ventilated children. Two blind protected BAL were done, at a 2-hour interval, in 30 patients. The reproducibility of microbiologic and cytologic results was studied. A total of 60 BALs was analyzed. Bacterial growth was present in 26 of 60 BAL (43%). Reproducibility for the presence of bacteria on quantitative cultures was excellent (concordance, 93%; kappa [kappa], 0.86). Concordance for the type of bacteria isolated was 86% and for the number of bacteria was 79%. Reproducibility for the presence of neutrophils containing bacteria was perfect (concordance, 100%; kappa, 1) although only a few BALs had a positive result (8/60). Blind protected BAL was feasible in all patients and all samples were considered adequate for analysis. Complications were mostly benign and transitory except in two cases: one pneumothorax and one significant increase in intracranial pressure. Overall, blind protected BAL is a reproducible test in mechanically ventilated children, is easily feasible, and is usually well tolerated.

Nosocomial infections in pediatric intensive care units

Nosocomial infections are a significant problem in pediatric intensive care units. While Indian estimates are not available, western PICUs report incidence of 6-8%. The common nosocomial infections in PICU are bloodstream infections (20-30% of all infections), lower respiratory tract infections (20-35%), and urinary tract infections (15-20%); there may be some differences in their incidence in different PICUs. The risk of nosocomial infections depends on the host characteristics, the number of interventions, invasive procedures, asepsis of techniques, the duration of stay in the PICU and inappropriate use of antimicrobials. Most often the child had endogenous flora, which may be altered because of hospitalization, are responsible for the infections. The common pathogens involved are Staphylococcus aureus, coagulase negative staphylococci, E. coli Pseudomonas aeruginosa, Klebsiella, enterococci, and candida. Nosocomial pneumonias predominantly occur in mechanically ventilated children. There is no consensus on the optimal approach for their diagnosis. Bloodstream infections are usually attributable to the use of central venous lines; use of TPN and use of femoral site for insertion increase the risk. Urinary tract infections occur mostly after catheterization and can lead to secondary bacteremia. The diagnostic criteria have been discussed in the review. With proper preventive strategies, the nosocomial infection rates can be reduced by up to 50%; handwashing, judicious use of interventions, and proper asepsis during procedures remain the most important practices.