Accuracy of single-breath counting test to determine slow vital capacity in hospitalized patients

Abstract

Purpose: to identify the accuracy of the single-breath counting test to determine slow vital capacity in hospitalized patients and to evaluate the repeatability of the same examiner. Methods: a diagnostic study and the choice of techniques were randomly assigned. The area under the curve (receiver operating characteristic) was calculated from the slow vital capacity (20ml/kg) to evaluate the best psychometric characteristics of single-breath counting Test for this cutoff point. Repeatability observed by the same examiner was assessed using the Intraclass Correlation Coefficient. Results: 516 patients hospitalized for various diseases were analyzed. In the curve analysis (receiver operating characteristic/slow vital capacity=20ml/Kg), the value of 21 in single-breath counting test with a sensitivity of 94.44% and specificity of 76.62% (area under the curve =0.93, p<0.005) was found. The intraclass correlation coefficient value for the single-breath counting test was 0.976 with p>0.005. Conclusion: the single-breath counting test was a valid and repetitive technique, and may be an important screening option for assessment of lung function in the absence of specific equipment. This technique opens perspectives to replace slow vital capacity measurement in hospitals, which lack spirometric equipment, or in patients who may have a contagious disease, which has a risk of contamination and spread of disease from one patient to another.

Correlation of peak expiratory flow rate and single breath count in normal adults

“…Also the intra class correlation coefficient for repeatability by the same examiner was 0.976 with p>0.005. 20 SBC has also been studied for the purpose of triaging respiratory complications and failure in neuromuscular conditions such as botulism, myasthenia gravis and Guillian-Barre syndrome.…”

Review of Physiological Rationale of Physiotherapy in Covid-19 Patients: A Case Series

“…The numerical count technique has a good correlation with the Slow Vital Capacity (SVC) with great intra-examiner repeatability. A count of 21 reflects SVC below 20 ml/kg [22]. Thus, useful in evaluating lung function in COVID-19 setups with a limitation of equipment for infection control, it is also used as bedside tool for assessment of pulmonary function in addition to being an exercise stimulus.…”

Regarding the article: “Maximum phonation time in the pulmonary function assessment”

“…The main contribution of the article related to the excellent agreement found between intra-examiners and the referral of these techniques to help in the understanding of lung function, in addition to presenting objective values of standard error of measurement in individuals without lung or parenchymal disease. The article itself opens up future possibilities, so that the single-breath counting test can be used to estimate SVC and monitor disease evolution in patients presented with COVID-19 SBC is a test in which individuals are asked to inhale as much air as possible and, during exhalation, to start counting numbers in an ascending order, starting with the number one to the largest number they can reach, in a single exhalation, maintaining the tone and intensity of a habitual phonation 2,3 . As lung function is directly related to voice production, individuals with limited lung functionality may have an altered SBC [2][3][4][5][6] .…”

“…The article itself opens up future possibilities, so that the single-breath counting test can be used to estimate SVC and monitor disease evolution in patients presented with COVID-19 SBC is a test in which individuals are asked to inhale as much air as possible and, during exhalation, to start counting numbers in an ascending order, starting with the number one to the largest number they can reach, in a single exhalation, maintaining the tone and intensity of a habitual phonation 2,3 . As lung function is directly related to voice production, individuals with limited lung functionality may have an altered SBC [2][3][4][5][6] . In addition, as it is a technique that makes it possible to quantitatively assess the emission, it is possible to develop research that compares pre and post treatment values, in different populations and in monitoring the disease's evolution.…”

“…For over 10 years, a group of Brazilian researchers has studied the relationship between SVC and SBC [2][3][4]12,13 , identifying a positive correlation both in hospitalized patients 12 and in young people without respiratory complaints 13 . Another important study group 3 evaluated an estimate of SVC from SVC in 221 hospitalized individuals.…”