SBC: A Do-It-Yourself Tool for Monitoring Lung Function

Single Breath Count (SBC) is a useful non-invasive (not involving the introduction of instruments into the body) measure for monitoring respiratory function. 

 

Single breath counting (SBC) is the measurement of how far an individual can count in a normal speaking voice after one maximal effort inhalation.


According to WHO, clinical management of severe acute respiratory infection, when novel coronavirus is suspected, SPO2 < 90% on room air is an important clinical syndrome (problem) associated with COVID-19. This is measured by a pulse oximeter. But all patients do not have pulse oximeters at home. Therefore, SBC can be a useful tool in monitoring the lung’s function.


SBC is measured by asking patients to take a deep breath and count as far as possible in their normal speaking voice without taking another breath. Patients having a breath count of 25 or less need to be sent to the emergency department for admission. Patients having a single breath count more than 40 can be monitored at home & can take treatment at home.

Advantage of SBC

    • Once taught, patients can do it by themselves at home.
    • Serial SBC reading can assess severity of lung involvement.
    • Daily comparison of SBC reading with decreasing trend gives indirect indication that patient’s lung condition is worsening & needs immediate consultation with a  medical expert or even hospitalisation.
    • No equipment is needed.
    • Can be done anywhere, everywhere & anytime except during sleep.
    • A useful tool which can help a physician to know a patient’s condition while doing tele-consultation.
    • By daily monitoring of a COVID-19- positive patients, a home-quarantined patient can be advised investigations & even hospitalization if SBC count decreases.

Disadvantage of SBC

    • Cannot be a reliable indicator in anxious, depressed, and illiterate patients.
    • Cannot be used in all patients. Especially those with certain situations like stroke, aphasic patients (a condition in which a patient is unable to comprehend, speak, read, or write) during febrile episodes (fever), dehydrated patients, elderly debilitated (weak body or mind) patients.
    • May create panic if patient’s SBC deteriorates at home especially if he or she is a COVID–19- positive.

Thus, SBC is a reliable tool for monitoring respiratory functions in COVID–19 times.  It is helpful for doctors during teleconsultation when a patient does not have a pulse oximeter at home.