Nonbronchoscopic lung lavage for diagnosis of opportunistic infection in AIDS

The role of mini-bronchoalveolar lavage fluid in the diagnosis of pulmonary tuberculosis in critically ill patients

BACKGROUND

The detection of Mycobacterium tuberculosis (MTB) in the intensive care unit (ICU) presents several challenges, mainly associated to the clinical state of the patient. The presence of HIV infection further aggravates this scenario, requiring a reliable collection method, with better performance in the microbiological/molecular techniques to be used. We evaluated the performance of two methods for sample collection, mini bronchoalveolar lavage (Mini-BAL) and endotracheal aspirate (ETA), for diagnosis of pulmonary tuberculosis (PTB) in critically ill patients.

METHODS

This prospective study involved 26 HIV positive ICU internalized patients, with presumptive PTB who required mechanical ventilation. Two samples were obtained prospectively from 26 HIV ICU patients with presumptive PTB by Mini-BAL and ETA. The samples were processed for smear microscopy, Löwenstein-Jensen medium and the BACTEC Mycobacteria Growth Indicator Tube 960 system®. We define as confirmed PTB patients with positive MTB culture. Furthermore, all samples obtained through the Mini-BAL were analyzed by Xpert® MTB/RIF.

RESULTS

Our results demonstrated that the respiratory samples obtained by Mini-BAL were able to increase MTB detection in critically ill patients with presumptive PTB. The Mini-BAL allowed 30% increased recovery and guaranteed enough sample volume for processing in all methods. In addition, the larger volume of the samples obtained with this technique enabled the Xpert® MTB/RIF molecular test for diagnosis of TB.

CONCLUSIONS

The Mini-BAL showed be an acceptable alternative to ETA in this population, since these critically ill and often-immunocompromised patients are more likely to develop complications related to invasive procedures.

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.

The role of bronchoalveolar lavage in the diagnosis of bacterial pneumonia

Bronchoalveolar lavage (BAL) has become an invaluable diagnostic tool with important clinical implications in both opportunistic infections and the pulmonary pathology of immunologic disease. Until recently, the use of BAL was limited primarily to two areas: the study of interstitial lung diseases and the diagnosis of lung infections by opportunistic microorganisms in severely immunocompromised patients with lung infiltrates. Over the past decade, the use of BAL has been expanded to include the conventional diagnosis of bacterial pneumonia in non-immunocompromised patients. In the past, different clinical studies proposed using BAL to quantify cultures in the sample obtained as a means of increasing the tool's effectiveness. Recent developments have led to a number of newer applications of BAL, such as bronchoscopic BAL, non-bronchoscopic BAL and protected BAL. The most important use of BAL in the non-immunocompromised patient is the diagnosis of pneumonia in the mechanically ventilated patient.

Comparison of Ballard catheter bronchoalveolar lavage with bronchoscopic bronchoalveolar lavage

BACKGROUND

Bronchoscopic bronchoalveolar lavage (BAL) in mechanically ventilated patients requires a large endotracheal tube, physician expertise, expensive equipment, and support staff.

METHODS

The Ballard BAL catheter is a disposable coude tip 16F device that can be attached to the endotracheal tube and ventilator circuit without loss of positive end-expiratory pressure (PEEP) and also allows supplemental delivery of oxygen between the 12F inner and outer catheters. The catheter is directed into the selected bronchus. The inner catheter with mushroom tip is then advanced until it wedges by feel. Thirteen patients at a tertiary care, university hospital, had BAL performed through both the bronchoscope and Ballard BAL catheter using five aliquots of 20 mL of normal saline solution each. The return was quantified and submitted for blinded, paired laboratory investigations, including Gram stain and quantitative culture, and special stains and cultures as clinically appropriate.

RESULTS

The procedure was well tolerated in all patients with no difference between devices in oxygen saturations; however, air leaks occurred in patients undergoing bronchoscopy and compromised safety in one. Two patients required reintubation to facilitate passage of the bronchoscope. The bronchoscopic BAL return averaged 49 mL (range, 5 to 85 mL) while BAL catheter averaged 37 mL (range, 18 to 70 mL) both being sufficient for all desired investigations except one patient who had undergone bronchoscopy. All were of excellent quality based on microscopy. The BAL results were concordant in nine patients: two Pneumocystis carinii, one Candida, one Streptococcus agalactiae, one Streptococcus pneumoniae, and no infection in four. Diagnoses of tuberculosis and Enterococcus (confirmed by blood culture) were obtained by the Ballard BAL catheter only. Kaposi's sarcoma and metastatic histiosarcoma were visualized by bronchoscope only. Two patients had compassionate plea use of the Ballard BAL catheter because of a small endotracheal tube. Hemorrhage secondary to lupus was documented in one and nosocomial infection was excluded in the other.

CONCLUSIONS

The Ballard BAL catheter allows easy, safe BAL, without loss of diagnostic yield, when visualization is not required in mechanically ventilated patients. The Ballard BAL catheter allows maintenance of PEEP when used with the supplied adapter and can be used with small endotracheal tubes.

Sputum induction compared with bronchoalveolar lavage by Ballard catheter to diagnose Pneumocystis carinii pneumonia

Specimens from sputum induction (SI) are often of insufficient volume or have poor diagnostic yield for the diagnosis of Pneumocystis carinii pneumonia (PCP). The Ballard catheter for bronchoalveolar lavage (BAL) is a disposable BAL device which is passed transnasally into the airway and wedged by sensation. Thirty consecutive episodes (21 inpatient and 9 outpatient) in 28 patients positive for HIV (15 with AIDS) were studied with SI and BAL at a tertiary-care university hospital. Six SIs yielded no specimen, and six were judged inadequate for investigation by the laboratory. The BAL return averaged 53 ml (range, 10 to 77 ml), and all specimens were excellent quality based on microscopy. Of the 10 patients (33 percent) who were PCP-positive on BAL, only 2 (6.9 percent) were detected by SI (McNemar p = 0.0078). Of 12 patients in whom SI was unobtainable or inadequate, 6 were positive for PCP on BAL. Two adequate specimens from SI were negative, but BAL specimens were positive for PCP. No patients had specimens that were positive for PCP on SI who had negative BAL specimens. The adequacy of the specimen and the PCP diagnosis with BAL were statistically superior to SI (McNemar p = 0.007). The Ballard BAL catheter allows easy transnasal access to the airway and safe BAL, with a statistically significant superior yield of specimens when compared to SI.

A simple method of bronchoalveolar lavage

Twenty-eight ventilated paediatric intensive care patients, mean age 4.1 +/- 4 years, who had had a simple method of nonbronchoscopic bronchoalveolar lavage (NB-BAL) performed were reviewed. The NB-BAL technique involved blindly wedging a 5 or 8F infant feeding catheter endobronchially and lavaging one millilitre per kg saline using a syringe. Adequate samples were collected in 87% of the NB-BAL specimens. In two of the four inadequate specimens, Pneumocystis carinii was still able to be identified. Additional information not obtained from the tracheal aspirate culture was seen in 71% of the NB-BAL samples. One-third of the patients also had a bronchoscopic BAL or a lung biopsy performed and the culture results were all identical to those obtained from NB-BAL. No significant complications were seen. Oxygenation and ventilation were not altered by the technique. We conclude that NB-BAL performed using a syringe and infant feeding catheter is a simple and cheap method that produces good alveolar samples in the majority of cases.

Nonbronchoscopic bronchoalveolar lavage in mechanically ventilated infants: technique, efficacy, and applications

Bronchoalveolar lavage with the fiberoptic bronchoscope is commonly used for the diagnosis of pulmonary infections in mechanically ventilated adults and children. However, its use for intubated infants is precluded because the small artificial airway does not permit the passage of the bronchoscope. We have developed a technique for nonbronchoscopic bronchoalveolar lavage, performed via a sterile, disposable feeding tube. We have used this technique in 15 infants with diffuse interstitial disease and/or atelectasis, while they were intubated and mechanically ventilated. The volume of the lavage effluent averaged 70.3% of the volume instilled. Specific diagnosis on the basis of the cytologic evaluation and/or culture of the lavage fluid was possible in 9 (60%) patients. Two patients with atelectasis showed radiographic evidence of improvement following the procedure. There were no complications. We conclude that nonbronchoscopic bronchoalveolar lavage is well tolerated, and clinically useful in small, mechanically ventilated infants with respiratory failure due to diffuse pulmonary disease. This technique provides a lower risk alternative to more invasive, and costly procedures.

Controlled trial of a continuous irrigation suction catheter vs conventional intermittent suction catheter in clearing bronchial secretions from ventilated patients

Continuous irrigation-suction catheter (Irri-cath) is a double-lumen device that allows for simultaneous saline solution infusion and aspiration. This system may theoretically be more effective than conventional dry intermittent suction due to its vortex principle. To test this hypothesis, we performed 200 suction maneuvers in 20 ventilated patients. Identically shaped catheters were used in a randomized sequence. For the same individual, we used equal instilled saline solution volume (40 ml), vacuum pressure (-180 cm H2O), and ventilatory parameters. Effectiveness of suction was determined by measuring the total aspirated volume, the dry lyophilized weight of secretion, the corrected dry weight (dry weight-weight of instilled salt), and protein concentration. No difference in heart rate, respiratory frequency, O2 saturation, systemic blood pressure, peak inspiratory pressure, or patient discomfort was found when the two modalities were compared; however, the total volume of secretions collected, the dry weight, the corrected dry weight, and the protein concentration were significantly higher with continuous irrigation suction catheter when compared with the conventional method (p < 0.05). The suction time was shorter with the Irri-cath (p < 0.05). We conclude that the Irri-Cath is more effective than conventional intermittent suction catheter in clearing bronchial secretions in patients on mechanical ventilation.

Bronchoscopy in the intensive care unit

The development of the flexible, fiberoptic bronchoscope has made bronchoscopic examinations possible in ICU patients undergoing mechanical ventilation. Over the years, the number of such procedures has greatly increased, with both diagnostic and therapeutic objectives, such as performing difficult intubation, management of atelectasis and hemoptysis, diagnosis of nosocomial pneumonia in ventilated patients, and early detection of airway lesions in selected situations, such as high-frequency ventilation. The complication rate can be kept low if the endoscopist has a precise knowledge of the many pathophysiological and technical facets particular to bronchoscopy under these difficult conditions. This article reviews some of these aspects, in the light of our personal experience.

Diagnosis of ventilator-associated pneumonia by bacteriologic analysis of bronchoscopic and nonbronchoscopic "blind" bronchoalveolar lavage fluid

Substantial efforts have been devoted to improving the means for early and accurate diagnosis of ventilator-associated (VA) pneumonia in intensive care unit (ICU) patients because of its high incidence and mortality. A good diagnostic yield has been reported from quantitative cultures of bronchoalveolar lavage (BAL) fluid or a protected specimen brush, both obtained by fiberoptic bronchoscopy. As bronchoscopy requires specific skills and is costly, we evaluated a simpler method to obtain BAL fluid, that is, by a catheter introduced blindly into the bronchial tree. Quantitative cultures from bronchoscopically sampled BAL (B-BAL) and blindly nonbronchoscopically collected BAL (NB-BAL) were assessed for sensitivity, specificity, and predictive value for the diagnosis of VA pneumonia. A total of 40 pairs of samples were examined in 28 patients requiring prolonged mechanical ventilation and presenting a high risk of developing pneumonia. For comparison with bacteriologic data we defined a clinical score for pneumonia ranging from zero to 12 using the following variables: body temperature, leukocyte count, volume and character of tracheal secretions, arterial oxygenation, chest X-ray, Gram stain, and culture of tracheal aspirate. To quantify the bacteria in BAL the bacterial index (BI) was used, defined as the sum of the logarithm of the number of bacteria cultured per milliliter of BAL fluid. A good correlation between clinical score and quantitative bacteriology was observed (r = 0.84 for B-BAL and 0.76 for NB-BAL; p less than 0.0001). Similar to studies in baboons, patients with pulmonary infection could be distinguished by a BI greater than or equal to 5 with a sensitivity of 93% and a specificity of 100% (B-BAL).(ABSTRACT TRUNCATED AT 250 WORDS)

Utility of bronchoscopic sampling techniques for cryptococcal disease in AIDS

Although cryptococcal pneumonia is a well recognized complication of the acquired immunodeficiency syndrome, optimal diagnostic approaches remain to be defined. During a 32-month period (October 1984 to June 1987), 11 patients were diagnosed with CP at our institution. The diagnosis was established in all 11 patients from specimens obtained via fiberoptic bronchoscopy (ten) and/or double-lumen catheter lavage (one). Direct stains of sedimented bronchoalveolar lavage were positive for organisms characteristic of Cryptococcus neoformans in nine of 11 patients. Transbronchial biopsies were positive (special histologic stains) in six of eight patients; bronchial washings were positive (direct smear) in seven of ten patients, the bronchial brushings were positive on stain in six of nine patients, and in one patient, a Wang transbronchial needle aspirate was positive on stain. Fungal cultures were positive on the BAL in seven of 11 patients, and on the bronchial washings in four of ten patients; the TBBx culture samples were all negative (zero of three). The serum cryptococcal antigen titer was elevated (median = 1:1024) in all eight patients in which it was assayed. Our data suggest that BAL and bronchial washings have a combined sensitivity on smear equal to that of TBBx and superior to that of TBBx fungal culture. The TBBx does not appear to be necessary in this setting. In addition, an elevated serum cryptococcal antigen titer appears to be an important adjunct in the evaluation of pulmonary infiltrates in AIDS.

Bronchoalveolar lavage in the evaluation of pulmonary disease in the dog and cat. State of the art

Bronchoalveolar lavage is a diagnostic procedure used to obtain specimens representative of disease processes involving the deep lung. Saline is instilled into an airway in sufficient volumes to bathe the alveoli dependent on that airway. The saline is retrieved by suction along with cellular and acellular material lining the epithelial surfaces of the lung. Cytologic and microbiologic evaluation of the fluid can be used to characterize pulmonary diseases in the dog and cat.

Tracheal catheters in patients with acquired immunodeficiency syndrome for the diagnosis of Pneumocystis carinii pneumonia

The diagnosis of Pneumocystis carinii pneumonia (PCP) often requires bronchoscopy. In 82 consecutive human immunodeficiency virus (HIV)-positive patients suspected of having PCP, we passed a 14-F catheter into the trachea under local anesthesia without intubation, instilled saline solution, and then collected the secretions by aspiration. Bronchoscopy with collection of bronchial washings and performance of bronchoalveolar lavage (BAL) was then performed and the results were compared. The catheter results were identical with the results of BAL in 77 of 82 patients. This inexpensive technique may provide a reasonable early step in the diagnosis of PCP.

Comparison of nonbronchoscopic bronchoalveolar lavage to open lung biopsy for the bacteriologic diagnosis of pulmonary infections in mechanically ventilated patients

We compared nonbronchoscopic bronchoalveolar lavage (NB-BAL) with open lung biopsy to determine the etiological diagnosis of lung infiltrates in patients requiring mechanical ventilation. NB-BAL was performed via a cuffed reusable 7F catheter generally used for right heart catheterization (BAL-C). In 13 patients, BAL-C and open lung biopsy were performed in the same lobe immediately after death when the ventilator was still functioning. No organism was cultured from BAL-C cultures when histopathologic examination of the lung showed no pneumonia and lung culture isolated no organism. Among the 10 positive BAL-C cultures, lung biopsy showed histologic pneumonia in 9 cases. Among these 9 pneumonia cases, 14 organisms were isolated in lung cultures and BAL-C correctly identified the causative agent in 13 cases. BAL-C appears to be an effective and safe procedure in the diagnosis of pulmonary infections in patients under mechanical ventilation who have previously received antibiotic therapy.

A review of pulmonary cytopathology in the acquired immunodeficiency syndrome

Over the past 6 yr, we have observed an increase in cytologic specimens from the respiratory tract in patients suspected or known to have AIDS, from 7 of 81,031 cases in 1982 to 1,231 of 55,333 in 1987. Based on our experience with 1,140 patients, this article reviews the technical and morphologic evaluation of pulmonary cytologic specimens from AIDS patients.

Quantitative pathology of coccidioidomycosis in acquired immunodeficiency syndrome

This study examines the laboratory aspects of diagnosis of coccidioidomycosis in 11 patients with acquired immunodeficiency syndrome (AIDS) and the qualitative and quantitative differences between host responses of AIDS and non-AIDS patients who died with disseminated coccidioidomycosis. Material obtained at bronchoscopy confirmed the diagnosis of pulmonary coccidioidomycosis in 67% (6/9) of the patients. Patients with AIDS had a generally poor granulomatous response and statistically significantly increased numbers of spherules in lung tissue compared with non-AIDS patients. Neither antifungal therapy nor duration of clinical disease influenced the number of organisms present. The findings suggest a parallel between AIDS-associated coccidioidomycosis and other granulomatous diseases such as leprosy and schistosomiasis, in which the type of granuloma formation and organism numbers are influenced by the T-lymphocyte milieu.