What is a Bronchoalveolar Lavage and why is it done?

Overview

Bronchoalveolar Lavage (BAL) is a minimally-invasive procedure that uses an instrument called bronchoscope to fill a portion of lungs with saline, after which, the saline water is sucked back. The water now contains cells from alveoli in the lungs. These are then examined under a microscope to understand the nature of the lung condition. In this article, we will examine the various situations when Bronchoalveolar Lavage (BAL) is done, how the procedure is done and risks associated with it.

Introduction

The lung is a complex organ with bronchial tubes branching out from the trachea (wind-pipe) and terminating in thousands of alveoli or air-sacs. Cells in the bronchial tubes and alveoli are a rich source of information on what is the health of the lung currently, and what is the ailment or condition that is affecting the lungs. So, harvesting these cells and examining them under the microscope is a useful diagnostic activity. This is achieved by what is called broncho-alveolar lavage (BAL) or broncho-alveolar washing (‘lavage’ means washing).

The washing is done by a minimally-invasive procedure that uses an instrument called bronchoscope. We have covered bronchoscopy in an earlier article. BAL is a specific application of bronchoscopy. Sterile saline (salt water) is used as the medium for washing. Saline is pumped into the bronchoscope from where it gets to the inner-most alveoli, and then sucked back using a syringe or suction pump. The harvested cells are isolated from the saline and examined under a microscope.

In addition to diagnosis, BAL can also be used as a therapy or treatment in certain lung conditions. This means, BAL can be used both as a diagnostic and a therapeutic procedure.

BAL for Diagnosis

• To detect infections such as bacterial pneumonia covid, tuberculosis and fungal pneumonia.
• To aid in the diagnosis of interstitial lung disorders such as sarcoidosis, pulmonary alveolar proteinosis and hypersensitivity pneumonitis
• To detect pneumonia in people on ventilators
• To rule-out certain disorders such as eosinophilic lung diseases and diffuse alveolar haemorrhage. This helps narrow down the diagnosis.
• To detect pulmonary vasculitides
• To detect occupational and environmental lung diseases such as those experienced by quarry workers, people working in chemical factories, those who handle asbestos and workers in recycling units
• To detect radiation-induced-pneumonitis in cancer patients

BAL for Therapy

 BAL is also used to treat a condition called pulmonary alveolar proteinosis (PAP). In this condition, proteins, fats and other substances (together called surfactant) build-up in the alveoli. Treating PAP uses a modified BAL technique where high volumes of sterile saline are pumped into the lungs using a dual-lumen endotracheal tube to achieve a whole-lung washing. This helps remove heavy lipoproteinaceous material from the lungs.

Preparing for the Procedure

The person must stop taking medication such as blood-thinners a few days before the BAL. He/she must not eat or drink anything 4 hours before the procedure. He/she must leave behind all aids such as dentures, contact lenses, glasses and bridges at home. He/she must be accompanied by somebody after discharge. BAL is an outpatient procedure done under local anaesthesia, however, if the patient so insists, general anaesthesia is given, in which case the person will have to stay in the hospital for a day.

Once admitted, the patient will lie on a bed with the arms on the side. He/she will be wheeled into the bronchoscopy suite, after which a mild sedative is injected into the arm. Numbing gel is rubbed into the nose while numbing medication is sprayed down the throat. All these helps reduce discomfort and the gagging reflex when the scope is pushed down the nose and throat. In case of general anaesthesia, the procedure is started after the patient is fully unconscious.

During the Procedure

The primary instrument used for BAL is a flexible video bronchoscope. Sterile collection-traps help hold the harvested lavage fluid while a suction device and suction tubing help in harvesting the lavage fluid. A source of sterile saline is connected to a sterilized bronchoscope. All these equipment are sterilized before start of the procedure.

Once the patient is sedated or unconscious, the video bronchoscope is lowered into the lower part of the lungs, called the tracheobronchial tree, wedged into place, and saline applied. A light and camera attached to the end of the scope help guide the movement. The camera relays images that are seen on a computer monitor kept in the OT. Once the saline is pumped in the required dose, and over multiple iterations, suction is applied to collect the lavage fluid. Alternately, the fluid is collected using a sterile syringe, through the irrigation channel in the scope. The collection trap which now holds the lavage fluid is labelled with the patient’s name and sent to the lab for testing.

After the Procedure

Once the patient regains consciousness, he/she will be monitored closely for vitals such as BP, heart rate, pulse and oxygen. His/her nose and mouth will feel numb for a couple of hours in which time, eating or drinking anything is prohibited as it can irritate the airways. Once the numbness goes away, he/she is given soft foods such as soups and porridges while he/she can consume water and beverages like tea, coffee, milk and juices. Patient is discharged the same day.

Risks from the Procedure

No to minimal risks if done under the right expertise and care.

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem and Bengaluru, the hospital also renders adult and pediatric trauma care.

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