What should I do for sputum testing if I don’t have phlegm?

Sputum examination typically involves collecting sputum specimens via spontaneous expectoration. If the patient is unable to produce sputum spontaneously, alternative methods may be employed—including nebulized mucolytic agents to facilitate expectoration, bronchoscopic sputum aspiration, or suctioning using a disposable suction catheter. Among these, suctioning with a disposable suction catheter is the most commonly used clinical method, as detailed below:

1. Prepare the following items in advance: a negative-pressure suction apparatus, disposable suction catheters, normal saline, gauze pads, a tongue depressor, a mouth gag, and a tongue forceps. Connect the disposable suction catheter to the suction apparatus and test its patency by aspirating a small amount of normal saline.

2. Position the patient in the supine or lateral decubitus position. Instruct the patient to open their mouth; if the patient is uncooperative, a mouth gag and/or tongue depressor may be used to assist.

3.  Gently insert the suction catheter into the oral cavity and aspirate secretions from the mouth and pharynx.

4.  Replace the suction catheter; fold the distal end of the catheter, then insert it into the trachea. Once the appropriate depth is reached, release the folded end and rotate the catheter gently while applying suction. Collect an adequate volume of the aspirated sputum for laboratory analysis.