Single breath count
Here is a prospective study that aimed to quantify how well Single Breath Count (SBC) could differentiate between patients having an asthma exacerbation and those not in exacerbation, with secondary goals of differentiating asthma from no asthma, and assessing response to bronchodilator treatment. Quite simply, SBC is how high your patient can count in a normal tone after a maximum inhalation.
What did they do? They took 162 patients aged 6y-16y and split them into 3 groups. Group 1 was found to be in a non-severe asthma exacerbation, Group 2 were patients with a history of asthma who were not in exacerbation, and Group 3 were the non-asthmatic controls. They measured SBC and pulmonary score (PS) on arrival for all patients, and post-salbutamol treatment in groups 1 and 2.
What did they find? Median SBC in Group 1 was 27 and improved to 32 post treatment. Pulmonary score improved from 4 to 2. In Group 2, SBC improved from 32 to 38. Group 3 had a baseline SBC of 35. I would've liked to see if the healthy group had an improvement in SBC with bronchodilator therapy; and I also wonder why the asthmatics not having an exacerbation improved more than those deemed to be in a mild-moderate exacerbation. They have a lot of spirometry data that shows improvement with bronchodilator therapy in Groups 1 & 2, with post-treatment values in Group 2 similar to the baseline numbers in Group 3. The authors state an SBC value of 28 is able to differentiate a mild/moderate exacerbation from no exacerbation, and a value of 32 to differentiate those with asthma from those without.
Bottom line: I think this will be clinically useful mostly in monitoring response to treatment/demonstrating to parents that the patient is getting better. I don't often find myself wondering, "Is this asthma or not?" in children >6 years old, or needing to perform a test to determine whether an asthmatic is having an exacerbation or not. I think this could also be an easy test to teach patients and parents for home- learn your baseline, and start to make note of which values are manageable at home and which require a trip to the ED.
What did they do? They took 162 patients aged 6y-16y and split them into 3 groups. Group 1 was found to be in a non-severe asthma exacerbation, Group 2 were patients with a history of asthma who were not in exacerbation, and Group 3 were the non-asthmatic controls. They measured SBC and pulmonary score (PS) on arrival for all patients, and post-salbutamol treatment in groups 1 and 2.
What did they find? Median SBC in Group 1 was 27 and improved to 32 post treatment. Pulmonary score improved from 4 to 2. In Group 2, SBC improved from 32 to 38. Group 3 had a baseline SBC of 35. I would've liked to see if the healthy group had an improvement in SBC with bronchodilator therapy; and I also wonder why the asthmatics not having an exacerbation improved more than those deemed to be in a mild-moderate exacerbation. They have a lot of spirometry data that shows improvement with bronchodilator therapy in Groups 1 & 2, with post-treatment values in Group 2 similar to the baseline numbers in Group 3. The authors state an SBC value of 28 is able to differentiate a mild/moderate exacerbation from no exacerbation, and a value of 32 to differentiate those with asthma from those without.
Bottom line: I think this will be clinically useful mostly in monitoring response to treatment/demonstrating to parents that the patient is getting better. I don't often find myself wondering, "Is this asthma or not?" in children >6 years old, or needing to perform a test to determine whether an asthmatic is having an exacerbation or not. I think this could also be an easy test to teach patients and parents for home- learn your baseline, and start to make note of which values are manageable at home and which require a trip to the ED.
