A Prospective Randomized Study Comparing Manual and Wall Suction in the Performance of Bronchoalveolar Lavage

Optimising the yield from bronchoalveolar lavage on human participants in infectious disease immunology research

Bronchoalveolar lavage (BAL) is becoming a common procedure for research into infectious disease immunology. Little is known about the clinical factors which influence the main outcomes of the procedure. In research participants who underwent BAL according to guidelines, the BAL volume yield, and cell yield, concentration, viability, pellet colour and differential count were analysed for association with important participant characteristics such as active tuberculosis (TB) disease, TB exposure, HIV infection and recent SARS-CoV-2 infection. In 337 participants, BAL volume and BAL cell count were correlated in those with active TB disease, and current smokers. The right middle lobe yielded the highest volume. BAL cell and volume yields were lower in older participants, who also had more neutrophils. Current smokers yielded lower volumes and higher numbers of all cell types, and usually had a black pellet. Active TB disease was associated with higher cell yields, but this declined at the end of treatment. HIV infection was associated with more bloody pellets, and recent SARS-CoV-2 infection with a higher proportion of lymphocytes. These results allow researchers to optimise their participant and end assay selection for projects involving lung immune cells.

Optimising the yield from bronchoalveolar lavage on human participants in infectious disease immunology research

Bronchoalveolar lavage (BAL) is becoming a common procedure for research into infectious disease immunology. Little is known about the clinical factors which influence the main outcomes of the procedure. In research participants who underwent BAL according to guidelines, the BAL volume yield, and cell yield, concentration, viability, pellet colour and differential count were analysed for association with important participant characteristics such as active tuberculosis (TB) disease, TB exposure, HIV infection and recent SARS-CoV-2 infection. In 337 participants, BAL volume and BAL cell count were correlated in those with active TB disease, and current smokers. The right middle lobe yielded the highest volume. BAL cell and volume yields were lower in older participants, who also had more neutrophils. Current smokers yielded lower volumes and higher numbers of all cell types, and usually had a black pellet. Active TB disease was associated with higher cell yields, and higher proportions of granulocytes, but this declined at the end of treatment. HIV infection was associated with lower cell yields and more bloody pellets, and recent SARS-CoV-2 infection with a higher proportion of lymphocytes. These results allow researchers to optimise their participant and end assay selection for projects involving lung immune cells.

Performance of a new single-use bronchoscope versus a marketed single-use comparator: a bench study

BACKGROUND

Single-use flexible bronchoscopes eliminate cross contamination from reusable bronchoscopes and are cost-effective in a number of clinical settings. The present bench study aimed to compare the performance of a new single-use bronchoscope (Boston Scientific EXALT Model B) to a marketed single-use comparator (Ambu aScope 4), each in slim, regular and large diameters.

METHODS

Three bronchoscopy tasks were performed: water suction and visualization, "mucus" mass (synthetic mucoid mixture) suctioned in 30 s, and "mucus" plug (thicker mucoid mixture) suction. Suction ability, task completion times, and subjective ratings of visualization and overall performance on a scale of one to 10 (best) were compared. All bronchoscopy tasks were completed by 15 physicians representing diversity in specialization including pulmonary, interventional pulmonary, critical care, anesthesia, and thoracic surgery. Each physician utilized the six bronchoscope versions with block randomization by bronchoscope and task.

RESULTS

Aspirated mean mass of "mucus" using EXALT Model B Regular was comparable to that for an aScope 4 Large (41.8 ± 8.3 g vs. 41.5 ± 5.7 g respectively, p = 0.914). In comparisons of scopes with the same outer diameter, the aspirated mean mass by weight of water and "mucus" was significantly greater for EXALT Model B than for aScope 4 (p < 0.001 for all three diameters). Mean ratings for visualization attributes were significantly better for EXALT Model B compared to aScope 4 (p-value range 0.001-0.029).

CONCLUSION

A new single-use bronchoscope provided strong suction capability and visualization compared to same-diameter marketed single-use comparators in a bench model simulation.

Wall-mounted Versus Handheld Syringe Suction for Pediatric Bronchoalveolar Lavage: A Randomized Controlled Trial

BACKGROUND

Bronchoalveolar lavage (BAL) via flexible bronchoscopy is a valuable diagnostic technique in children. The quality of BAL is directly related to the volume of the fluid recovered. Continuous wall suctioning and handheld syringe suctioning are the 2 commonly used methods, but they are rarely compared in children. We aimed to compare the above 2 suctioning techniques for BAL in the pediatric age group.

METHODS

This randomized controlled study enrolled children from 1 month to 18 years of age undergoing flexible bronchoscopy and BAL. We compared continuous wall suctioning and the handheld syringe suctioning technique. The primary outcome was the percentage of BAL fluid recovery in 2 different suctioning techniques. Secondary outcomes included technical acceptable BAL and yield of various diagnostic tests in BAL.

RESULTS

The study included 73 children (48 boys) with a median (interquartile range) age of 30 (8, 108) months. There were 37 children in the wall mount group and 36 children in the syringe suction group. Baseline characteristics of the groups were similar. The wall mount suction had more recovery of BAL fluid compared with the syringe method (43.6±8.4% vs. 37.8±8.5%, P=0.004). The proportion of BAL having a fluid recovery of ≥40% was also high in the wall mount suction [31 (83.8%) vs. 17 (47.2%); P=0.001]. There was no difference in diagnostic yield between the groups.

CONCLUSION

Wall mount suction had better BAL fluid recovery compared with handheld syringe suction in children undergoing flexible bronchoscopy. The diagnostic yield was similar in both groups.

Non-bronchoscopic Bronchoalveolar Lavage as a Refinement for Safely Obtaining High-quality Samples from Macaques

Nonbronchoscopic bronchoalveolar lavage (NB-BAL) is a minimally invasive diagnostic and research tool used to sample the cells of lower airways and alveoli without using a bronchoscope. Our study compared NB-BAL and bronchoscopic bronchoalveolar lavage (B-BAL) in terms of costs, cell yields, and the number of post-procedural complications in macaques. We also analyzed procedure times, BAL fluid volume yields, and vital signs in a subset of animals that underwent NB-BAL. Compared with the B-BAL technique, NB-BAL was less expensive to perform, with fewer complications, fewer animals requiring temporary or permanent cessation of BALs, and higher cell yields per mL of recovered saline. The average procedure time for NB-BAL was 6.8 ± 1.6 min, and the average NB-BAL lavage volume yield was 76 ± 9%. We found no significant differences in respiration rate before, during, or after NB-BAL but did find significant differences in heart rate and oxygen saturation (SpO₂). This study demonstrates that NB-BAL is a simple, cost-effective, and safe alternative to B-BAL that results in higher cell yields per mL, improved animal welfare, and fewer missed time points, and thus constitutes a refinement over the B-BAL in macaques.

The Effect of Lung Lavage Volume Return on the Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Bronchoalveolar lavage (BAL) is a commonly used tool in the diagnosis of ventilator-associated pneumonia (VAP). Previous protocols recommend 30% lavage return, though no studies have investigated this relationship. This study aims to assess the influence of BAL volume return on VAP diagnosis.

MATERIALS AND METHODS

A retrospective review was performed of a prospectively maintained database for BAL performed from January 2015 to January 2016 in the trauma and surgical ICU at a level 1 trauma center. In total, 147 ventilated patients with clinical suspicion for pneumonia underwent 264 BALs. A protocol was used with five aliquots of 20 cc of saline instilled. Quantitative cultures were performed with 10ˆ5 colony-forming organisms as the threshold for VAP diagnosis. BAL was repeated at 6-8 d on 50 patients. Univariate and multivariate regression analyses were performed to investigate the predictors of VAP diagnosis.

RESULTS

Patients with >40% lavage return had increased rates of VAP diagnosis (odds ratio [OR] 2.86, P = 0.002). Increasing volume return also trended toward a lower false-negative rate. Temperature, leukocytosis, and X-ray infiltrate were not associated with increased VAP diagnosis. Concurrent antibiotic therapy at the time of BAL predicted decreased VAP diagnosis (OR 0.58, P = 0.04). On multivariable analysis, only >40% return remained associated with increased rate of VAP diagnosis (OR 4.00, P = 0.004).

CONCLUSIONS

This study found that >40% lavage volume return was associated with increased VAP diagnosis. Clinicians should consider the reliability of a negative BAL if clinical suspicion of VAP is high and lavage return is <40%. Additional investigation is needed to further elucidate this association.

Guidelines for diagnostic flexible bronchoscopy in adults: Joint Indian Chest Society/National College of chest physicians (I)/Indian association for bronchology recommendations

Flexible bronchoscopy (FB) is commonly performed by respiratory physicians for diagnostic as well as therapeutic purposes. However, bronchoscopy practices vary widely across India and worldwide. The three major respiratory organizations of the country supported a national-level expert group that formulated a comprehensive guideline document for FB based on a detailed appraisal of available evidence. These guidelines are an attempt to provide the bronchoscopist with the most scientifically sound as well as practical approach of bronchoscopy. It involved framing appropriate questions, review and critical appraisal of the relevant literature and reaching a recommendation by the expert groups. The guidelines cover major areas in basic bronchoscopy including (but not limited to), indications for procedure, patient preparation, various sampling procedures, bronchoscopy in the ICU setting, equipment care, and training issues. The target audience is respiratory physicians working in India and well as other parts of the world. It is hoped that this document would serve as a complete reference guide for all pulmonary physicians performing or desiring to learn the technique of flexible bronchoscopy.

Basic Bronchoscopy: Technology, Techniques, and Professional Fees

Flexible bronchoscopy has evolved over the last few decades, allowing chest physicians to use advanced high-definition scopes to inspect the airways and perform various sampling techniques. Although the techniques of basic bronchoscopic sampling have not changed dramatically, documentation requirements, coding, and billing have become more complex and require a better understanding on the part of the proceduralists and practice administrators. Areas in need of attention include learning about the multiple endoscopy rule, appropriate use of modifiers, and recent changes to the Current Procedural Terminology codes, associated work relative value units for moderate sedation, and therapeutic aspiration of secretions. This article describes basic bronchoscopic procedures and the principles needed for their coding and billing.

Effect of a syringe aspiration technique versus a mechanical suction technique and use of N-butylscopolammonium bromide on the quantity and quality of bronchoalveolar lavage fluid samples obtained from horses with the summer pasture endophenotype of equine asthma

OBJECTIVE To evaluate the effect of 2 bronchoalveolar lavage (BAL) sampling techniques and the use of N-butylscopolammonium bromide (NBB) on the quantity and quality of BAL fluid (BALF) samples obtained from horses with the summer pasture endophenotype of equine asthma. ANIMALS 8 horses with the summer pasture endophenotype of equine asthma. PROCEDURES BAL was performed bilaterally (right and left lung sites) with a flexible videoendoscope passed through the left or right nasal passage. During lavage of the first lung site, a BALF sample was collected by means of either gentle syringe aspiration or mechanical suction with a pressure-regulated wall-mounted suction pump. The endoscope was then maneuvered into the contralateral lung site, and lavage was performed with the alternate fluid retrieval technique. For each horse, BAL was performed bilaterally once with and once without premedication with NBB (21-day interval). The BALF samples retrieved were evaluated for volume, total cell count, differential cell count, RBC count, and total protein concentration. RESULTS Use of syringe aspiration significantly increased total BALF volume (mean volume increase, 40 mL [approx 7.5% yield]) and decreased total RBC count (mean decrease, 142 cells/μL), compared with use of mechanical suction. The BALF nucleated cell count and differential cell count did not differ between BAL procedures. Use of NBB had no effect on BALF retrieval. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that retrieval of BALF by syringe aspiration may increase yield and reduce barotrauma in horses at increased risk of bronchoconstriction and bronchiolar collapse. Further studies to determine the usefulness of NBB and other bronchodilators during BAL procedures in horses are warranted.