Novel method of noninvasive ventilation supported therapeutic lavage in pulmonary alveolar proteinosis proves to relieve dyspnea, normalize pulmonary function test results and recover exercise capacity: a short communication

May noninvasive mechanical ventilation and/ or continuous positive airway pressure increase the bronchoalveolar lavage salvage in patients with pulmonary diseases? Randomized clinical trial - Study protocol

PURPOSE

Bronchoalveolar lavage (BAL) procedure is a useful tool in the diagnosis of patients with interstitial lung disease (ILD) and is helpful in clinical research of chronic obstructive pulmonary disease (COPD) patients. Still little is known about predictors of poor BAL salvage. The trial aims to find the most efficient way to improve BAL recovery.

MATERIAL AND METHODS

Our study is a prospective, multicenter, international, two-arm randomized controlled trial. We aim to obtain BAL samples from a total number of 300 patients: 150 with ILD and 150 with COPD to achieve a statistical power of 80 ​%. Patients with initial BAL salvage <60 ​% will be randomized into the non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) arm. The NIV and CPAP will be set according to the study protocol. The influence on BAL salvage will be assessed in terms of BAL volume and content. Multivariable analysis of the additional test results to determine predictors for low BAL recovery will be conducted. In a study subgroup of approximately 20 patients per specific disease, a metabolomic assessment of exhaled air condensate will be performed. All procedures will be assessed in terms of the patient's safety. The trial was registered on clinicaltrials.gov (ID# NCT05631132). Interested experienced centers are invited to join the research group by writing to the corresponding author.

CONCLUSION

The results of our prospective study will address the currently unsolved problem of how to increase BAL salvage in patients with pulmonary diseases without increasing the risk of respiratory failure exacerbation.

The use of non-invasive respiratory assistance to facilitate bronchofiberoscopy performance in patients with hypoxemic (type one) respiratory failure - Study protocol

PURPOSE

Bronchofiberoscopy (FOB) is a procedure routinely performed for: lung cancer, obstruction, interstitial diseases, foreign bodies' removal, airway clearance, and hemoptysis. It causes acute airway narrowing leading to respiratory and cardiovascular stress. Due to increasing number of ill patients with respiratory failure (RF), conventional oxygen therapy (COT) is frequently insufficient to assure accurate oxygenation and prevent RF in patients requiring FOB. In this clinical scenario, patients may be intubated and supported with invasive mechanical ventilation (IMV) with the specific aim of allowing a safe FOB. However, this invasive strategy is associated with an increased risk of IMV-associated complications.

MATERIALS AND METHODS

Our study is a planned prospective multicenter three-arm randomized controlled trial (RCT). The target number of 300 patients was calculated based on the intubation risk in RF patients, which is 0.2-2%. The patients will be assigned to each arm based on Horowitz index. In each arm, the patients will be randomly assigned to one out of two dedicated respiratory support methods in each group i.e. COT/high flow nasal cannula (HFNC), HFNC/non-invasive ventilation (NIV) and NIV/IMV. In the manuscript the current state of art in the area of respiratory support is discussed. We have underlined knowledge gaps in medical evidence which we are planning to reveal with our results.

RESULTS

The results of our study are clinically crucial, because they address current gaps concerning COT/HFNC/NIV/IMV.

CONCLUSION

The expected findings of this study would allow for careful selection of respiratory support method to safely perform FOB in patients with hypoxemic RF.

Use of high-flow nasal cannula and intravenous propofol sedation while performing flexible video bronchoscopy in the intensive care unit: Case reports

Flexible video bronchoscopy is a procedure that plays an important role in diagnosing various types of pulmonary lesions and abnormalities. Case 1 is a 68-year-old male patient with a lesion in the right lung apex of approximately 4 mm × 28 mm with atelectasis bands due to a crash injury. High-flow system with 35 L/min and fraction of inspired oxygen (FiO₂) 0.45 and temperature of 34 °C was installed prior to the video bronchoscopy. SpO₂ was maintained at 98%-100%. The total dose of sedative was 50 mg of propofol. In Case 2, a 64-year-old male patient with bronchiectasis, cystic lesions and pulmonary fibrosis of the left lung field was placed on a high-flow system with 45 L/min and 0.35 FiO₂ at a temperature of 34 °C. SpO₂ was maintained at 100%. The total duration of the procedure was 25 min; SpO₂ of 100% was sustained with oxygenation during maintenance time with the flexible bronchoscope within the airway. The total dose of propofol to reach the degree of desired sedation was 0.5-1 mg/kg. Both patients presented hypotension. For the patient of case 1, a vasopressor (norepinephrine at doses of 0.04 µg/kg/min) was given, and for the patient of case 2, only saline volume expansion was used. The video bronchoscopy with propofol sedation and high-flow nasal cannula allows adequate oxygenation during procedure in the intensive care unit.

Risk factors of complications during noninvasive mechanical ventilation -assisted flexible bronchoscopy

PURPOSE

Flexible bronchoscopy (FB) causes airway narrowing and may cause respiratory failure (RF). Noninvasive mechanical ventilation (NIV) is used to treat RF. Until recently, little was known about noninvasive mechanical ventilation assisted flexible bronchoscopy (NIV-FB) risk and complications.

MATERIALS AND METHODS

A retrospective analysis of NIV-FB performed in 20 consecutive months (July 1, 2018-February 29, 2020) was performed. Indications for: FB and NIV, as well as impact of comorbidities, blood gas results, pulmonary function test results and sedation depth, were analyzed to reveal NIV-FB risk. Out of a total of 713 FBs, NIV-FB was performed in 50 patients with multiple comorbidities, acute or chronic RF, substantial tracheal narrowing, or after previously unsuccessful FB attempt.

RESULTS

In three cases, reversible complications were observed. Additionally, due to the severity of underlining disease, two patients were transferred to the ICU where they passed away after >48h. In a single variable analysis, PaO₂ 69 ​± ​18.5 and 49 ​± ​9.0 [mmHg] (p ​< ​0.05) and white blood count (WBC) 10.0 ​± ​4.81 and 14.4 ​± ​3.10 (p ​< ​0.05) were found predictive for complications. Left heart disease indicated unfavorable NIV-FB outcome (p ​= ​0.046).

CONCLUSIONS

NIV-FB is safe in severely ill patients, however procedure-related risk should be further defined and verified in prospective studies.

Pulmonary alveolar proteinosis: A single center retrospective analysis of 14 cases

INTRODUCTION

Pulmonary alveolar proteinosis (PAP) is a rare lung disease, characterized by abnormal alveolar accumulation of enlarged foamy macrophages and periodic acid-Schiff (PAS)-positive materials. Knowledge of the disease characteristics is still lacking.

OBJECTIVE

To help clinicians gain a better understanding of this rare disease.

METHODS

We undertook a retrospective analysis of 14 adult patients with PAP, treated in Zhongshan Hospital, Fudan University.

RESULTS

Serum lactate dehydrogenase (LDH) was correlated with the arterial partial pressure of oxygen (PaO2) and diffusion capacity for carbon monoxide (DLCO). Transbronchial lung biopsy (TBLB) established a definitive diagnosis for a positive rate of 100%. The patients underwent whole lung lavage (WLL) and exhibited varying degrees of remission. The patients with mild symptoms received only supportive care and observation, and remained stable during follow-up.

CONCLUSION

LDH may correlate with disease severity. Bronchoscopy is sufficiently sensitive for a definite diagnosis. Conventional bilateral whole lung lavage proved a reliable treatment for indicated patients, but selective unilateral lung lavage or observation may be a rational choice in certain patients.

Noninvasive Ventilation-Facilitated Bronchofiberoscopy in Patients with Respiratory Failure

Respiratory failure is one of the most important risk factors for diagnostic bronchofiberoscopy (BF), whereas therapeutic bronchoscopies are typically performed in intubated patients. Only a few published studies analyzed the outcomes of noninvasive mechanical ventilation (NIV)-facilitated BF. In this case series, we present our experiences with NIV-facilitated diagnostic and therapeutic BF performed in patients with respiratory failure that was associated with acute interstitial pulmonary disease, chronic obstructive pulmonary disease, cystic fibrosis exacerbation, foreign body aspiration, tracheal stenosis, pneumonia, and in a patient with a neuromuscular disease. All of the patients were initially hypoxic and some had PaO₂/FiO₂ < 200, which corresponded to moderate-to-acute respiratory distress syndrome (ARDS). NIV-facilitated BF were performed for the diagnostic or therapeutic purposes. The former consisted of bronchoalveolar lavage and bacterial sampling in a patient with impaired cough reflex, airway assessment in otherwise unexplained respiratory failure and hemoptysis, and the latter of mucous plugs resolution, foreign body removal, and assistance in weaning from mechanical ventilation. All procedures were carried out using NIV in the spontaneous timed (ST) or average volume assured pressure support (AVAPS) mode with oxygen supplementation. There were no procedure-related complications noticed during NIV-facilitated BF. We conclude that NIV is a useful and safe tool that facilitates the performance of BF in severe pulmonary diseases. Prospective studies are required to set the recommendations for the procedure and to define the optimum ventilatory modes to be used.