Abstract
Objective: To measure the correlation between single breath counting (SBC) and forced vital capacity (liters, FVCL) in amyotrophic lateral sclerosis (ALS) patients and to define the utility of SBC for determining when patients meet the threshold for initiation of noninvasive positive pressure ventilation (FVC < 50% predicted [FVCpred]). Methods: Both patient paced (SBCpp) or externally paced (SBCep) counting along with FVCL+pred and standard clinical data were collected. Linear regression was used to examine SBCpp and SBCep as a predictor of FVCL. Receiver operating characteristic curve analysis evaluated the sensitivity and specificity of SBC categorically predicting FVCpred of ≤50%. Results: In 30 ALS patients, SBC explained a moderate proportion of the variance in FVCL (SBCpp: R 2= 0.431, p < 0.001; SBCep: R 2 = 0.511, p < 0.01); this proportion improved when including covariates (SBCpp: R 2= 0.635, p < 0.01; SBCep: R 2= 0.657, p < 0.01). Patients with minimal speech involvement performed similarly in unadjusted (SBCpp: R 2 = 0.511, p < 0.01; SBCep: R 2= 0.595, p < 0.01) and adjusted (SBCpp: R 2 = 0.634, p < 0.01; SBCep: R 2= 0.650, p < 0.01) models. SBCpp had 100% sensitivity and 60% specificity (area under curve (AUC) = 0.696) for predicting FVCpred <50%. SBCep had 100% sensitivity and 56% specificity (AUC = 0.696). With minimal speech involvement SBCpp and SBCep both had 100% sensitivity and 76.1% specificity (SPCpp: AUC = 0.845; SBCep: AUC = 0.857). Conclusions: SBC explains a moderate proportion of variance in FVC and is an extremely sensitive marker of poor FVC. When FVC cannot be obtained, such as during the current COVID-19 pandemic, SBC is helpful in directing patient care.
Highlights
Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disorder that is uniformly fatal
We examined single breath counting (SBC) as a screening tool for determining when patients would need to initiate Noninvasive positive pressure ventilation (NIPPV)
An receiver operating characteristic (ROC) analysis was used to evaluate the sensitivity and specificity of SBC categorically predicting FVCpred of 50%, a common criteria for initiating NIPPV
Summary
Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disorder that is uniformly fatal. Most ALS multidisciplinary clinics are managing people with ALS, who are considered a high-risk population, using telemedicine techniques. In the absence of a formal VC measurement, a method to estimate VC would help guide clinical decisions, such as the timing of initiating NIPPV. The single breath count (SBC) is a bedside screen widely used to estimate the respiratory muscle strength. SBC may be useful as a screening method for respiratory muscle weakness in people with ALS when formal VC measurement is not possible. We aimed to measure the strength of the relationship between forced vital capacity (FVC) and SBC in a sample of our ALS clinic patients. We examined SBC as a screening tool for determining when patients would need to initiate NIPPV (conventionally when FVC is less than 50% of predicted value)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
