Quantitative Bronchoalveolar Lavage Cultures Research Articles

Serum procalcitonin as an early inflammatory marker in pediatric ventilator-associated pneumonia

Background: Delayed diagnosis of ventilator-associated pneumonia (VAP) in pediatric patients is associated with accentuated risk of morbidities and mortality. Early diagnosis of VAP is challenging. Serum procalcitonin has been proposed as a promising inflammatory marker for the early diagnosis of VAP, but there is a lack of sufficient evidence for the use of serum procalcitonin for early diagnosis of VAP in children. The present study was conducted to determine the role of serum procalcitonin as an early inflammatory marker for an early and provisional diagnosis of VAP among clinically suspected VAP patients in pediatric intensive care unit settings. Subjects and Methods: Seventy-nine pediatric patients (age: 1 month–18 years) with suspected VAP (Simplified Clinical Pulmonary Infection Score >6) were prospectively evaluated with quantitative bronchoalveolar lavage cultures and simultaneously tested for serum procalcitonin levels. Two groups were identified based on culture results and comparatively evaluated for procalcitonin levels, its diagnostic efficacy, antibiotic usage patterns, and mechanical ventilation duration. Results: The VAP group had 39 patients, and the non-VAP group had 40 patients. Thirty-two (82%) patients in the VAP group had a procalcitonin value ≥10 ng/ml as against 10 (25%) from the non-VAP group. Two (5.1%) patients in the VAP group had procalcitonin levels ≤1 ng/ml as against 21 (52.5%) patients in the non-VAP group. The receiver operating characteristic area under curve for procalcitonin with a cutoff >10 ng/ml was 0.785 (95% confidence interval = 0.678–0.870) with a sensitivity of 82.05% and specificity of 75%. Conclusions: Serum procalcitonin is a reliable biomarker to augment the provisional diagnosis of VAP in clinically suspected cases. Such diagnosis may help in an early institution of definitive therapy for VAP.

Use of endotracheal tubes with subglottic secretion drainage reduces ventilator-associated pneumonia in trauma patients.

Patients sustaining traumatic injuries have a higher incidence of ventilator-associated pneumonia (VAP) compared with other critically ill patient populations. Previous studies of patients with predominantly medical diagnoses and use of endotracheal tubes allowing subglottic secretion drainage (ETT-SSD) have shown significant reduction in VAP rates. We hypothesized that the use of ETT-SSD would reduce VAP in trauma patients. A retrospective review from 2010 to 2014 of adult trauma patients orotracheally intubated for more than 48 hours was performed at a Level 1 trauma center. Patients were compared based on standard endotracheal tube (ETT) versus ETT-SSD for the primary outcome VAP per 1,000 ventilator days. The diagnosis of VAP was made by quantitative bronchoalveolar lavage cultures as defined by Centers for Disease Control and Prevention criteria. Patients with ETT-SSD were matched to patients with ETT based on age group, sex, mechanism of injury, head and chest Abbreviated Injury Scale (AIS) score, and Injury Severity Score (ISS). Of 1,135 patients included in the study, 667 patients had ETT and 468 had ETT-SSD. Groups did not differ by demographics, mechanism of injury, Glasgow Coma Scale (GCS) score, alcohol intoxication, or ISS. Patients with ETT-SSD had significantly higher head AIS score but lower chest AIS score. In matched cohorts, ETT-SSD had a lower VAP rate (5.7 vs. 9.3 for ETT, p = 0.03), decreased ventilator days (12 vs. 14, p = 0.04), and decreased intensive care unit length of stay (13 days vs. 16 days, p = 0.003). After controlling for confounding factors, ETT-SSD decreased VAP rate, ventilator days, and intensive care unit length of stay in trauma patients. In this high-risk patient population, we recommend routine use of ETT-SSD to decrease VAP. Therapeutic/care management study, level III.

Diagnostic accuracy of inflammatory biomarkers in bronchoalveolar lavage from patients with ventilator-associated pneumonia

BackgroundVentilator associated pneumonia (VAP) is a common complication in intensive care patients. The clinical diagnosis is difficult and a definite microbiological diagnosis based on quantitative culture of bronchoalveolar lavage (BAL) fluid is mandatory. Many biological markers have been studied in an effort to improve the rapidity and performance of current diagnostic procedures in VAP. So, this study was done with the objective to determine the discriminative power of single or combining multiple biomarkers in bronchoalveolar lavage including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), soluble urokinase plasminogen activator receptor (suPAR), and macrophage migration inhibitory factor (MIF) for the diagnosis of bacterial VAP among patients who were receiving mechanical ventilation. Patients and methodsThis study was conducted in the intensive care units of Chest, Internal Medicine and Anesthesia Departments, Zagazig University Hospitals, Egypt, between January and December 2012, 66 adult patients were included who were receiving mechanical ventilation and eligible for BAL for suspected VAP. The microbiology was assessed with quantitative cultures of BAL obtained within the first 6h after the development of a new pulmonary infiltrate on chest radiography. All patients were divided into: Group 1, “definite VAP” with positive quantitative culture results, Group 2, “indeterminate VAP” with negative BAL culture and received new antibiotics at least 24h prior to BAL, and Group 3, “definite absence of VAP,” with negative BAL culture and not receiving antibiotics at the time of BAL. MeasurementsProcalcitonin was measured using an ultrasensitive chemiluminometric assay. CRP was measured using an enzyme immunoassay. Measurements of sTREM-1, suPAR, and MIF were performed using a Luminex multiplex assay. Two composite markers were constructed; one including a linear combination of the three best performing markers and another including all six markers and the area under the receiver operating characteristic curve (AUC) was used to compare their performance and those of the individual markers. ResultsOf the total 66 enrolled patients receiving mechanical ventilation and undergoing BAL for suspected pneumonia, 20 patients (30.3%) met definite microbiologic criteria for group 1, 28 patients (42.4%) with indeterminate VAP in group 2, and 18 patients (27.2%) with definite absent VAP in group 3. The mean concentrations of all studied biomarkers were not statistically significant when their levels in BAL samples from patients with definite VAP were compared with either from definite absence of VAP or from indeterminate VAP (all p>0.05). The AUCs for discrimination between infection of bacterial origin and no infection were 0.83 (95% CI 0.79–0.88) for CRP, 0.77 (95% CI 0.69–0.79) for PCT, 0.72 (95% CI 0.67–0.77) for neutrophils, 0.60 (95% CI 0.83–0.69) for MIF, 0.68 (95% CI 0.56–0.67) for sTREM-1 and 0.51 (95% CI 0.48–0.59) for suPAR, 0.86 (0.79–0.89|) for the composite three-marker test (CRP, PCT, and neutrophils), and 0.90 (0.83–0.96) for the composite six-marker test. The six-marker test performed significantly better than all of the single markers (P<0.05 for the three-marker test and CRP and P<0.001 for the five remaining markers). ConclusionsSingle measurements of sTREM-1, suPAR or MIF concentrations in the BAL fluid of mechanically-ventilated patients with new or progressive infiltrates do not enhance identification of VAP. However, combining results from several inflammatory markers may significantly improve the ability to differentiate bacterial from nonbacterial infections. Further studies are needed to fully determine the diagnostic accuracy of these and other biomarkers.

Anesthesia Literature Review

Anesthesia Literature Review

Incidence of nosocomial pneumonia and risk of recurrence after antimicrobial therapy in critically ill lung and heart–lung transplant patients

Little is known about the resolution of symptoms of nosocomial pneumonia (NosoP) after lung and heart-lung transplantation. The aim of this study was to describe the clinical response to antimicrobial therapy in (ICU) patients with NosoP after lung or heart-lung transplantation. Between January 2008 and August 2010, 79 lung or heart-lung transplantations patients were prospectively studied. NosoPwas confirmed by quantitative cultures of bronchoalveolar lavage or endotracheal aspirates. Clinical variables, sequential organ failure assessment (SOFA) score, and radiologic score were recorded from start of therapy until day 9. Thirty-five patients (44%) experienced 64 episodes of NosoP in ICU. Fourteen patients (40%) had NosoP recurrence. Most frequently isolated organisms were Enterobacteriaceae (30%), Pseudomonas aeruginosa (25%), and Staphylococcus aureus (20%). Sequential organ failure assessment (SOFA) score improved significantly at day 6 and C-reactive protein level at day 9. SOFA and radiologic scores differed significantly between patients with and without NosoP recurrence at day 3 and 9. The ICU mortality rate did not differ between patients with and without NosoP recurrence, and free of NosoP (14.3%, 9.5%, 11.4%, respectively) (p=0.91). Severities of illness and lung injury were the two major risk factors for NosoP recurrence. Occurrence of NosoP has no impact on ICU mortality.

Early Antibiotic Discontinuation in Patients With Clinically Suspected Ventilator-Associated Pneumonia and Negative Quantitative Bronchoscopy Cultures*

Preliminary data suggest that antibiotic discontinuation in patients with negative quantitative bronchoscopy and symptom resolution will not increase mortality. Because our hospital algorithm for antibiotic discontinuation rules out ventilator-associated pneumonia in the setting of negative quantitative bronchoscopy cultures, we compared antibiotic utilization and mortality in empirically treated, culture-negative ventilator-associated pneumonia patients whose antibiotic discontinuation was early versus late. Retrospective, observational cohort study. Eight hundred sixty-seven bed, tertiary care, teaching hospital in Hartford, CT. Eighty-nine patients with clinically suspected ventilator-associated pneumonia and a negative (<10 colony forming units/mL) quantitative bronchoscopy culture between January 2009 and March 2012. Early discontinuation patients (n = 40) were defined as those who had all antibiotic therapy stopped within one day of final negative culture report, whereas late discontinuation patients (n = 49) had antibiotics stopped later than one day. Univariate analyses assessed mortality, antibiotic duration, and frequency of superinfections. Multivariate logistic regression was performed to assess the effect of early discontinuation on hospital mortality. Patients had a mean ± SD Acute Physiology and Chronic Health Evaluation II score of 26.0 ± 6.0. Mortality was not different between early discontinuation (25.0%) and late discontinuation (30.6%) patients (p = 0.642). Antibiotic duration (days) was also not different for patients who died vs. those who survived (Median [interquartile range]: 3 [1-7.5] vs. 3 [1.75-6.25], respectively, p = 0.87), and when controlling for baseline characteristics and symptom resolution, only Acute Physiology and Chronic Health Evaluation II score was associated with hospital mortality on multivariate analyses. There were fewer superinfections (22.5% vs. 42.9%, p = 0.008), respiratory superinfections (10.0% vs. 28.6%, p = 0.036), and multidrug resistant superinfections (7.5% vs. 35.7%, p = 0.003), in early discontinuation compared with late discontinuation patients. In this severely ill population with clinically suspected ventilator-associated pneumonia and negative quantitative bronchoalveolar lavage cultures, early discontinuation of antibiotics did not affect mortality and was associated with a lower frequency of MDR superinfections.

Postliver Transplantation Pulmonary Complications

We read the article by Levesque et al. (1) with great interest. We congratulate the authors for addressing this important issue in the critical care of liver transplant recipients. We have few queries regarding the study. Until date, to our knowledge, this is the first study in cohort of liver transplant recipients using modified clinical pulmonary infection score (CPIS) to diagnose pneumonia. CPIS has been originally devised for diagnosis of ventilator-associated pneumonia (VAP) (2), and the authors did not mention the incidence of VAP. The authors used the modified CPIS score to confirm the diagnosis of pneumonia, which excludes the culture results (3). CPIS is still not validated for the diagnosis of VAP and has low sensitivity, 60%, and specificity, 43%, if it excludes the culture results (4). It would be great to know the sensitivity and specificity of CPIS score in this cohort as compared with quantitative bronchoalveolar lavage culture. In this study, there were 55 episodes of pneumonia; out of that, only 39 are reported to be culture positive. It means that, for 16 times, no microorganism was isolated. The protocol for antibiotics is for 48 hr after transplantation; how many patients were on antibiotics when they were diagnosed to have pneumonia? History of acute cellular rejection is an independent risk factor for developing pneumonia (5). The incidence of rejection in the study population is not mentioned. It will be interesting to know the risk of pneumonia in this subset of patients. In the pulmonary complication group, how many patients were having associated renal dysfunction that required dialysis? It might affect pulmonary complications (5). Did the authors control the ascites and pleural effusion before performing the pulmonary function test because it might improve patient compliance? At one point, it is stated that age is not the risk factor, but is the P value significant? Patients with upper abdominal surgery are expected to have some pleural effusion during the immediate postoperative period; however, in this study, pleural effusion was evaluated on the seventh day after the transplantation on computed tomographic scan as per routine protocol. Are there any other methods (bedside chest x-ray and ultrasound) used to evaluate pleural effusion before 7 days? How many patients experienced early effusion? Shridhar V. Sasturkar 1 Viniyendra Pamecha1 Vijay Kant Pandey2 1 Department of Hepatico-Pancreatic-Biliary Surgery and Liver Transplantation Institute of Liver and Biliary Sciences New Delhi, India 2 Department of Anesthesiology and Intensive Care Institute of Liver and Biliary Sciences New Delhi, India

Reasons for Low Bacterial Yields from Quantitative Cultures of Bronchoalveolar Lavage Fluid

Reasons for Low Bacterial Yields from Quantitative Cultures of Bronchoalveolar Lavage Fluid

Bacterial Yield from Quantitative Cultures of Bronchoalveolar Lavage Fluid in Patients with Pneumonia on Antimicrobial Therapy

Background/AimsEarly diagnosis and appropriate antimicrobial choice are crucial when managing pneumonia patients, and quantitative culture of bronchoalveolar lavage (BAL) fluid is considered a useful method for identifying pneumonia pathogens. We evaluated the quantitative yield of BAL fluid bacterial cultures in patients being treated with antimicrobials and attempted to identify factors predictive of positive BAL cultures.MethodsPatients over 18 years old and whose BAL fluid was subjected to quantitative culture to identify the organism causative of pneumonia between January 1, 2005, and December 31, 2009, were included. We reviewed the results of BAL fluid bacterial cultures and the clinical records, laboratory tests, and radiographic findings of the patients.ResultsBAL was performed on 340 patients with pneumonia. A positive BAL culture, defined as isolation of more than 104 colony forming units/mL bacteria, was documented in 18 (5.29%) patients. Of these, 9 bacteria isolated from 10 patients were classified as probable pathogens. The most frequently isolated bacteria were methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa. No independent predictive factor for positive BAL cultures was identified.ConclusionsThe yield of quantitative BAL fluid bacterial culture in patients already on antimicrobials was low. Clinicians should be cautious when performing a BAL culture in patients with pneumonia who are already on antimicrobials.

Diagnostic use of serum procalcitonin levels in pulmonary aspiration syndromes*

To assess the predictive accuracy of serum procalcitonin in distinguishing bacterial aspiration pneumonia from aspiration pneumonitis. Prospective observational study. Intensive care unit of a university-affiliated hospital. Sixty-five consecutive patients admitted with pulmonary aspiration and seven control subjects intubated for airway protection. None. Quantitative cultures from bronchoalveolar lavage fluid were conducted on all participants at the time of admission. Serial serum procalcitonin levels were measured on day 1 and day 3 using the procalcitonin enzyme-linked fluorescent assay. There were no differences in the median serum concentrations of procalcitonin between patients with positive bronchoalveolar lavage cultures (n = 32) and patients with negative bronchoalveolar lavage cultures (n = 33) on either day 1 or day 3 postadmission. The areas under the receiver operator characteristic curves were 0.59 (95% confidence interval, 0.47-0.72) and 0.63 (95% confidence interval, 0.5-0.75), respectively (p = .74). However, duration of mechanical ventilation and antibiotic therapy were shorter in those who had a decrease in their procalcitonin levels on day 3 from baseline compared with those who did not (6.7 ± 7.1 days and 11.1 ± 13.5 days, p = .03; and 8.2 ± 2.6 days vs. 12.8 ± 4.6 days; p < .001, respectively). Hospital mortality was associated with radiographic multilobar disease (adjusted odds ratio, 1.14; 95% confidence interval, 1.01-1.31; p = .04) and increasing procalcitonin levels (adjusted odds ratio, 5.63; 95% confidence interval, 1.56-20.29; p = .008). Serum procalcitonin levels had poor diagnostic value in separating bacterial aspiration pneumonia from aspiration pneumonitis based on quantitative bronchoalveolar lavage culture. However, serial measurements of serum procalcitonin may be helpful in predicting survival from pulmonary aspiration.

Insulin Resistance Heralds Positive Cultures after Severe Injury

Insulin resistance and hyperglycemia are common in acutely injured patients, and associated with poor outcomes. In the era of tight glucose control, measures of insulin responsiveness (IR) may provide a better indicator of patient status than does the serum glucose concentration. We hypothesized that measures of IR during tight glycemic control protocols are associated with infection and may be more predictive than the serum glucose concentration. All critically injured, mechanically ventilated patients undergo protocolized tight glycemic control with the aid of a computer-based system that calculates the insulin dose using an adapting multiplier (insulin dose = [blood glucose - 60) x M). Consecutive patients on protocol were studied to identify the incidence of positive sterile-site or quantitative bronchoalveolar lavage cultures (>10(4) colony-forming units/mL). Patients were stratified by presence and number of positive cultures and analyzed by both serum glucose measures and measures of IR (average multiplier and average insulin infusion rate). During the six-month study period, 356 patients were placed on the tight glycemic control protocol. Of these, 101 patients had 192 positive cultures. Patients with positive cultures required significantly more hourly insulin than those without a positive culture (3.7 vs. 2.8 units/h; p = or<0.001). Logistic regression showed the insulin dose (odds ratio 2.1; 95% confidence interval 1.6, 3.0; p = <0.001) and the adapting multiplier to be independent predictors of the patient having a positive culture among other factors associated with nosocomial infection. Insulin resistance, quantified by hourly insulin dose and median multiplier, confers a higher risk of systemic nosocomial infection. Patients with positive cultures actually had lower admission and median blood glucose values over their intensive care unit stays, highlighting the decreased value of this measure as a predictor of outcome in the setting of tight glucose control. A greater insulin requirement suggesting resistance may be used as a marker of a higher risk of nosocomial infection.

Usefulness of procalcitonin for the diagnosis of ventilator-associated pneumonia

To assess the predictive capacity for the diagnosis of ventilator-associated pneumonia (VAP) of serum procalcitonin levels before and on the day it is suspected. Single-center observational study in the intensive care unit of a teaching hospital. Consecutive patients whose serum procalcitonin levels were available on the day that VAP was clinically suspected (day 1) and at some time within the preceding 5 days ("before"). Serum procalcitonin levels were determined on day 1 and "before". Among the 73 suspected episodes VAP was confirmed by quantitative bronchoalveolar lavage cultures in 32 and refuted in 41. Respective median "before" procalcitonin levels were 1.89 ng/ml (interquartile range 0.18-6.01) and 2.14 (0.76-5.75) in patients with and without VAP, but their respective median day-1 procalcitonin levels did not differ: 1.07 ng/ml (0.39-6.57) vs. 1.40 (0.67-3.39). On day 1 a 0.5 ng/ml procalcitonin threshold had 72% sensitivity but only 24% specificity for diagnosing VAP. Between "before" and day 1, procalcitonin increased in 41% and 15% of patients with and without VAP, respectively. Thus a procalcitonin rise on day 1, compared to its "before" level, had 41% sensitivity and 85% specificity for diagnosing VAP, with respective positive and negative predictive values of 68% and 65%. Crude values and procalcitonin rise had poor diagnostic value for VAP in this particular setting and thus should not be used to initiate antibiotics when VAP is clinically suspected.

Diagnostic strategies for nosocomial pneumonia

This review describes advances in clinical and microbiological modalities for diagnosis of nosocomial pneumonia and the role of biological markers. Serial assessments with the clinical pulmonary infection score identifies nonsurvivors and allows discontinuation of antibiotics when there is low suspicion of pneumonia. Studies evaluating its clinical utility show mixed results. A meta-analysis revealed that an invasive approach does not affect mortality but reduces costs, antibiotic exposure, and multidrug resistance. In contrast to these findings, a recent trial comparing nonquantitative endotracheal aspirate and quantitative bronchoalveolar lavage cultures showed similar clinical outcomes and antibiotic utilization. The role of quantitative endotracheal aspirate for diagnosis of pneumonia not related to mechanical ventilation was recently evaluated. Procalcitonin and soluble triggering receptor expressed on myeloid cells-1 aid in diagnosis, identify sepsis related to ventilator-associated pneumonia and patients with worst outcomes. The diagnostic modality chosen depends on availability, personnel experience, and the patient's clinical status. Recent guidelines support the use of quantitative cultures in an integrated clinical and microbiological algorithm. The decision to adjust antibiotics involves clinical reassessment and interpretation of culture results. Biological markers have a potential role as screening and prognostic tools.

Antimicrobial Resistance of Bacteria Isolated from Bronchoalveolar lavage (BAL) in Patients with Lung Infiltrations in Burn and Non-Burn Intensive Care Unit

연구배경: 원내 폐렴의 적절한 항균제 치료를 위해서는 원발 병소에서의 원인균 규명과 항균제에 대한 내성 유무 확인이 필수적이다. 본 연구는 원내 폐렴이 의심되는 경우 기관지내시경을 통한 정량적 기관지폐포 세척술(bronchoalveolar lavage, BAL) 배양검사를 시행하여 빈번하게 분리되는 균주와 이들의 항균제 내성 현황을 알아보고자 하였다. 방법: 2004년 1월부터 2006년 6월까지 한림의대 한강성심병원 화상 중환자실과 비화상 중환자실에서 폐 침윤의 원인규명 위해 BAL 검사를 시행하였다. 104 CFU/mL 이상의 균주가 분리되면 양성으로 판정하였다. 결과: BAL 검사 결과 화상중환자실 27예(77.1%), 비화상중환자실 22예(59.4%)에서 배양 양성이었다. 분리되는 주요 균주는 S. aureus, Acinetobacter species 및 P. aeruginosa였다. 화상중환자실에서 분리된 S. aureus의 경우 전부 MRSA(100%)였으며, 비화상중환자실에서는 71.4%가 MRSA로 보고되었다. P. aeruginosa의 경우 화상중환자실 및 비화상중환자실에서 amikacin 54.6% vs. 50.0%, ciprofloaxacin 100% vs. 50%, cefepime 90.9% vs. 50%, imipenem 72.7% vs. 50%, ceftazidime 45.5% vs. 25% 및 piperacillin/tazobactam 90.9% vs. 50%의 내성률을, Acinetobacter species의 경우는 amikacin 90.9% vs. 100%, ciprofloxacin 100% vs. 87.5%, cefepime 90.9% vs. 100%, imipenem 100% vs. 62.5%, ceftazidime 90.9% vs. 100% 및 piperacillin/tazobactam 81.8% vs. 62.5%의 내성률을 보여주었다. 결론: 화상중환자실과 비화상중환자실에서 원내 폐렴이 의심되는 환자의 원인균 분포와 약제 내성 현황을 알 수 있었으며 향후 항균제 치료 전략에 도움을 줄 것으로 사료된다.

Transfusions Result in Pulmonary Morbidity and Death after a Moderate Degree of Injury

Prior studies have suggested that blood transfusion (Tx) is associated with infectious and respiratory complications in trauma patients. However, these studies are difficult to interpret because of small sample size, inclusion of severely injured patients in traumatic shock, and combination of a variety of unrelated low-morbidity/mortality infections, such as wound, catheter-related, and urinary tract infection as outcomes. To eliminate these confounding variables, this study evaluates the association between delayed Tx and serious, well-defined respiratory complications (ventilator-associated pneumonia [VAP] and acute respiratory distress syndrome [ARDS]) and death in a cohort of intensive care unit (ICU) admissions with less severe (Injury Severity Score [ISS] < 25) blunt trauma who received no Tx within the initial 48 hours after admission. Patients with blunt injury and ISS < 25 admitted to the ICU over a 7-year period were identified from the registry and excluded if within 48 hours from admission they received any Tx or if they died. VAP required quantitative bronchoalveolar lavage culture (> or =10(5) colonies/mL), and ARDS required Pao2/Fio2 ratio < 200 mm Hg, *** no congestive heart failure, diffuse bilateral infiltrates, and peak airway pressure > 50 cm H2O for diagnosis. Outcomes were VAP, ARDS, and death. Nine thousand one hundred twenty-six with blunt injury were ICU admissions, and 5,260 (58%) met study criteria (72% male). Means for age, ISS, and Glasgow Coma Scale score were 39, 12, and 14, respectively. There were 778 (15%) who received delayed Tx. Incidences of VAP, ARDS, and death were 5%, 1%, and 1%, respectively. Logistic regression analysis identified age, base excess, chest Abbreviated Injury Scale score, ISS, and any transfusion as significant predictors for VAP; chest Abbreviated Injury Scale score and transfusion as significant predictors for ARDS; and age and transfusion as significant predictors for death. Delayed transfusion is independently associated with VAP, ARDS, and death in trauma patients regardless of injury severity. These data mandate a judicious transfusion policy after resuscitation and emphasize the need for safe and effective blood substitutes and transfusion alternatives.

Primary pulmonary lymphangiectasia in infancy and childhood.

Primary pulmonary lymphangiectasia (PPL) is a rare disorder of unknown aetiology characterised by dilatation of the pulmonary lymphatics. PPL is widely reported to have a poor prognosis in the neonatal period and little is known about the clinical features of patients who survive the newborn period. The current authors report the outcome in nine patients diagnosed in infancy with PPL over a 15-yr period at a single university-based hospital clinic and followed for a median of 6 yrs. Although all of the patients initially experienced respiratory distress, respiratory symptoms improved in most patients after infancy and were notably better by the age of 6 yrs. Many patients had poor weight gain in the first years of life, which eventually improved. Radiological scans showed progressive resolution of neonatal infiltrates, but were characterised by hyperinflation and increased interstitial markings in older children. Most patients had evidence of bronchitis and grew pathogenic organisms from quantitative bronchoalveolar lavage culture. Pulmonary function tests showed predominantly obstructive disease that did not deteriorate over time. In conclusion, these results suggest that primary pulmonary lymphangiectasia does not have as dismal a prognosis as previously described and symptoms and clinical findings improve after the first year of life.

Variation of infected cell count in bronchoalveolar lavage and timing of ventilator-associated pneumonia.

The aim of this study was to evaluate and compare the accuracy of the percentage of infected cells (%IC) in bronchoalveolar lavage (BAL) for ventilator-associated pneumonia (VAP) diagnosis according to its onset from the initiation of mechanical ventilation. One hundred and eight patients admitted to a surgical ICU were retrospectively included (1999-2001). A total of 171 cases of VAP were diagnosed on clinical, biological, chest X-ray and BAL results (threshold >/=10(4 )cfu/ml). The %IC significantly decreased with the timing of VAP diagnosis: 12.2+/-12.1% for VAP occurring less than 7 days after the initiation of mechanical ventilation, 7.4+/-9.2% for VAP occurring between 7 and 15 days and 4.8+/-6.4% for VAP after 15 days ( p=0.0002), despite the same number of elements and proportion of polymorphonuclear neutrophils in BAL. In addition, a relationship between the %IC and the pathogen responsible for VAP was observed for P. aeruginosa [higher for VAP <7 days than for VAP 7-15 days ( p=0.01) and VAP >15 days ( p=0.006)] and S. aureus [lower for VAP >15 days than VAP 7-15 days ( p=0.04) and VAP <7 days ( p=0.04)]. Furthermore, the %IC in BAL was lower in patients undergoing antimicrobial therapy than in patients without antibiotics ( p=0.04). Three factors were independently associated with the %IC: quantitative culture of BAL (beta=0.42, p<0.0001), ongoing antimicrobial therapy (beta= -0.21, p=0.003) and onset of VAP (beta= -0.17, p=0.01). A relationship between the %IC in BAL, duration of ventilation, quantitative culture of BAL and ongoing antimicrobial therapy has been proved in this study. The %IC for VAP diagnosis may not be accurate in patients with ongoing antibiotics and late onset infections (>7 days).

Quantitative culture of bronchoalveolar lavage fluid in community-acquired lower respiratory tract infections

To evaluate the diagnostic value of quantitative bacterial culture of bronchoalveolar lavage (BAL) fluid obtained by fibreoptic bronchoscopy, 67 consecutive immunocompetent adult patients admitted to hospital with community-acquired lower respiratory tract infections from September 1997 to May 1998 were investigated. Results were compared to the findings in eight healthy control persons investigated in February 1998. There was no difference between study patients and control persons when quantitative culture of total cumulative bacterial findings or bacteria categorized as members of the oropharyngeal normal flora were compared. The culture of normal flora in bronchial washings probably reflects contamination of the lower airways with secretions from upper airways by the fibreoptic procedure itself, as fractionated sampling showed a 10-fold reduction in quantitative culture results when a primary bronchial washing was compared to a secondary sampling from the same bronchus in the control group. Twenty-four (36%) of 67 patients were cultured as positive in the study group while all control persons were cultured as negative for bacteria categorized as potential pathogens. With a threshold value for positive culture of 104cfu ml−1the specificity of lavage culture of potential pathogenic bacteria in relation to actual lower airway infection was 100%. Therefore, quantitative bacterial culture of potential pathogenic bacteria in BAL fluid is very specific but only positive in about one-third of unselected immunocompetent adult patients with a lower respiratory tract infection.

Resolution of infectious parameters after antimicrobial therapy in patients with ventilator-associated pneumonia.

Although recommended durations of antimicrobial therapy for ventilator-associated pneumonia (VAP) range from 7 to 21 d, these are not based on prospective studies and little is known about the resolution of symptoms after start of antibiotics. Resolution of these symptoms was investigated in 27 patients. VAP was diagnosed on clinical, radiographic, and microbiological criteria, including quantitative cultures of bronchoalveolar lavage. All patients received appropriate antibiotic therapy. Highest temperatures, leukocyte counts, Pa(O(2))/FI(O(2)) ratios, and semiquantitative cultures of endotracheal aspirates were recorded from start of therapy until Day 14. Resolution was defined as the first day that these parameters fulfilled the following definition: temperature < or = 38 degrees C, leukocytes < or = 10 x 10(9)/L, Pa(O(2))/FI(O(2)) ratio > or = 25 kPa, and no or +1 of bacterial growth of etiologic pathogens in cultures of endotracheal aspirate. VAP was caused by Enterobacteriaceae (n = 14), P. aeruginosa (n = 7), S. aureus (n = 6), H. influenzae (n = 3), and S. pneumoniae (n = 1). H. influenzae and S. pneumoniae were eradicated from tracheal aspirates, whereas Enterobacteriaceae, S. aureus, and P. aeruginosa persisted, despite in vitro susceptibility to antibiotics administered. Significant improvements were observed for all clinical parameters, most apparently within the first 6 d after start of antibiotics. Newly acquired colonization, especially with P. aeruginosa and Enterobacteriaceae, occurred in the second week of therapy. Six patients developed a recurrent episode of VAP, four of them with P. aeruginosa. Clinical responses to therapy for VAP occur within the first 6 d of therapy, endotracheal colonization with Gram-negative bacteria persists despite susceptibility to therapy, and acquired colonization usually occurs in the second week of therapy and frequently precedes a recurrent episode.

Accuracy and precision of quantitative calibrated loops in transfer of bronchoalveolar lavage fluid.

Quantitative cultures of bronchoalveolar lavage (BAL) fluid are important in the diagnosis of ventilator-associated pneumonia, and calibrated loops are commonly used to set up these cultures. In this study, the performances of calibrated 0.010- and 0.001-ml loops in the transfer of BAL fluid were determined. Five loops of one lot from seven manufacturers were tested. Calibrations were performed by the gravimetric method (0.010-ml loops) and the colorimetric method (0.001-ml loops). Most of the 0.010-ml loops displayed a precision that was less than 10%, but six of them showed very poor accuracies as they transferred a deficiency (nichrome loops) or an excess (disposable loops) of BAL fluid that exceeded +/-10%. The mean maximum and minimum BAL fluid volumes delivered by the 0.010-ml loops differed by a factor 3. The 0.001-ml loops displayed acceptable precision. Five of them showed inaccuracies of </=+/-10%, and mean maximum and minimum BAL fluid volumes had a range of a factor of 2. For all loops, the volumes of BAL fluid sampled were larger than the volumes of reagent-grade water sampled. Results of the colony counting experiments confirmed these findings and revealed a high intra-assay variability for the 0.001-ml loops. We conclude that, when BAL fluid samples are cultured with calibrated loops, (i) proper verification of the calibration of these loops is mandatory, (ii) calibrations should be performed with BAL fluid as the test solution, and (iii) borderline quantitative culture results should be interpreted with knowledge of the inaccuracy values of these loops.