
Overview
This module describes how to induce an adult or child to produce sputum if not obtainable through coughing.
Indications
Obtaining a sputum sample from a patient who cannot produce sputum spontaneously
Contraindications
Patients with O2 saturation of < 92% despite supplemental oxygen
Patients with severe bronchospasm
Patients unable to protect their airways
Recent seizure in a patient with known seizure disorder
Patient information & consent
How do I explain this procedure?
“I need to collect a sample of the fluid in your lungs, which usually is coughed up as sputum when you are ill. This is not the same as the normal spit in your mouth or the mucous in the back of your throat.”
What can my patient expect?
“For this test, you will need to breathe in a mist of salty water that will help you to cough more effectively. It may make you feel nauseated or short of breath. Afterwards, the test results can take a few days or weeks to come out.”
What is my patient’s role?
“Try to keep breathing in the mist; don’t take the mask off your face. When you’re asked to cough, try to cough even if you don’t feel like it. Try to spit out sputum from your throat, not just spit from your mouth. Tell me if you feel nauseated, dizzy, or short of breath.”
Preparation
Prepare a trolley with equipment.
Work in an
area
Some institutions have sputum booths. Sputum production is an aerosol-producing activity, which may require PPE.
with good ventilation, away from other patients. Ideally, the patient should be fasted for 3 hours.

Documentation
Laboratory request forms and patient labels
Equipment
Non-sterile gloves
- 4.5% hypertonic saline4.5% hypertonic saline
You can use any sterile saline, but hypertonic saline works the best.
Salbutamol metered-dose inhaler
Nebuliser
Wall oxygen
Specimen jars
Specimen bag
Site & Positioning
Position the patient sitting up.
Procedure
Follow medical asepsis with non-sterile gloves.
Perform hand hygiene. Don gloves.
Assemble the nebuliser and fill with 5 ml hypertonic saline. Attach to wall oxygen.
Don an N95 respirator and check that it fits correctly and has a good seal.
Seat the patient and administer 200-400 mcg
salbutamolsalbutamolNebulised saline causes bronchoconstriction, so salbutamol premedication is a safety precaution.
.
Fit the nebuliser mask to their face.
Open the specimen jars and place within reach of the patient.
Switch on wall oxygen to 6-8 L/min.
After 5 minutes, switch off and remove the nebuliser. Encourage the patient to cough up sputum.
Repeat for two more 5 minute intervals.
If the patient coughs spontaneously during an interval, collect any sputum produced.
Don gloves, then close the specimen jars and label them. Fill in the laboratory request form. Place the specimens in the specimen bag with the form and send it to the laboratory.
Dispose of medical waste, including PPE, safely.
Record completion of the procedure in patient notes.
Troubleshooting
My patient is a young child who is struggling to cough on command.
Use a suction device to suction mucous from the nasopharynx to expel into the specimen pot. If this is still unsuccessful, consider gastric washings for a very young child.
The sample is very watery and I think it is saliva.
Induced sputum samples are usually more watery than spontaneously produced sputum.
Risks
Bronchospasm
Nausea & vomiting, aspiration
Hyperventilation and fainting
Healthcare provider exposure to infectious substances
References
Zar HJ, Tannenbaum E, Apolles P, et al. Sputum induction for the diagnosis of pulmonary tuberculosis in infants and young children in an urban setting in South Africa. Archives of Disease in Childhood. 2000;82:305-308.
Pizzichini MM, Leigh R, Djukanović R, Sterk PJ. European Respiratory Journal. 2002;20(37):9s-18s.
Grant LR, Hammitt LL, Murdoch DR, O’Brien KL, Scott AJ. Procedures for Collection of Induced Sputum Specimens From Children. Clinical Infectious Diseases. 2012;54(2):S140–S145.