A Comparison of Indirect and Direct Methods for Estimating Transglottal Airflow Rate

Single breath counting technique to assess pulmonary function: a systematic review and meta-analysis

Pulmonary function is usually assessed by measuring Vital Capacity (VC) using equipment such as a spirometer or ventilometer, but these are not always available to the population, as they are relatively expensive tests, difficult to transport and require trained professionals. However, the single breath counting technique (SBCT) appears as a possible alternative to respiratory function tests, to help in the pathophysiological understanding of lung diseases. The objective is to verify the applicability of the SBCT as a parameter for evaluating VC. This is a systematic review registered in the International Prospective Register of Systematic Reviews (CRD42023383706) and used for PubMed®, Scientific Electronic Library Online, LILACS, EMBASE, and Web of Science databases of articles published until January 2023. Methodological quality regarding the risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 and National Institutes of Health tools. Eleven of a total of 574 studies were included, of these, nine showed a correlation between VC and SBCT (weak in healthy, moderate in neuromuscular and strong in hospitalized patients). One study of hospitalized patients accurately identified a count value of 21 for a VC of 20 ml kg-1(Sensitivity = 94% and Specificity = 77%), and another estimated a count lower than 41 for a VC below 80% of predicted in patients with neuromuscular dystrophy (Sensitivity = 89% and Specificity = 62%), and another showed good intra and inter-examiner reproducibility in young, adult, and elderly populations. A meta-analysis of three studies showed a moderate correlation in subjects with neuromuscular diseases (r= 0.62, 95% CI = 0.52-0.71,p< 0.01). A high risk of bias was identified regarding the justification of the sample size and blinding of the evaluators. SBCT has been presented as an alternative to assess VC in the absence of specific equipment. There is a clear relationship between SBCT and VC, especially in neuromuscular and hospitalized individuals. New validation studies conducted with greater control of potential bias risks are necessary.

Respiratory and Sound Pressures, Maximum Phonation Time, Cervical Disability and Voice-Related Quality of Life of Teachers

INTRODUCTION

Many teachers report discomfort and a decrease in the quality of aerodynamic, respiratory, and cervical vocal aspects as well as of vocal self-assessment.

OBJECTIVE

Characterize and correlate measurements of Sound Pressure Levels, Maximum Phonation Time of /a/, Maximum Respiratory Pressures, Voice-Related Quality of Life and cervical pain in teachers with vocal and musculoskeletal complaints and no organic vocal fold lesions, and compare with normative values.

METHODS

Retrospective study with 56 teachers. Anamnesis, video laryngoscopy, hearing screening, measurements of sound pressure and maximum phonation time, and manovacuometry were performed. Self-assessment protocols for Voice-Related Quality of Life and Neck Disability Index were completed.

RESULTS

there was significant higher Sound Pressure Levels; significant lower Maximum Phonation Time of /a/, Maximum Expiratory Pressure, and total and physical scores of Voice-Related Quality of Life; most participants had mild cervical disability; there was a negative correlation between Maximum Expiratory Pressure and Neck Disability Index, between Maximum Inspiratory Pressure and Maximum Sound Pressure Level, and between Neck Disability Index and Voice-Related Quality of Life.

CONCLUSION

The results showed that there are damages and inadequacies in teachers' vocal production which affect their quality of life. Therefore, it is necessary to pay attention to the conditions of use of the voice by professionals, and to their health education.