Clinical and functional prediction of moderate to severe obstructive sleep apnoea

Abstract

Introduction: Upper airway inflammation and narrowing are characteristics of obstructive sleep apnoea (OSA). Inflammatory markers have been found to be increased in exhaled breath and induced sputum of patients with OSA. Objectives: The aim of this study was to investigate if the measurement of exhaled nitric oxide (FENO), as marker of airway inflammation, together with the forced mid-expiratory/mid-inspiratory airflow ratio (FEF50/FIF50), as marker of upper airway narrowing, may help to predict OSA. Methods: Two hundred one consecutive outpatients with suspected OSA were prospectively studied between January 2004 and December 2005. All patients underwent clinical examination, spirometry with measurement of FEF50/FIF50, maximum inspiratory pressure, arterial blood gas analysis, exhaled nitric oxide (FENO) and overnight polysomnography. Linear regression models were used to evaluate the effect of measured variables on the apnoea-hypopnoea index (AHI). Models were cross-validated by bootstrapping. Results: Most of the patients were obese and had severe OSA. FEF50/FIF50, FENO and an interaction term between smoking and FENO contributed significantly to the predictive model for AHI, in addition to age, neck circumference, body mass index and carboxyhaemoglobin saturation. A nomogram to predict AHI was obtained, which converted the effect of each covariate in the model to a 0-100 scale. The nomogram showed a good predictive ability for AHI values between 25 and 64. Conclusions: The measurement of FENO and of FEF50/FIF50 improves the ability to predict OSA and may be used to identify patients who require a sleep study. EthicsThe study was approved by the local ethics committee, and patients gave their informed consent to the study.

Exhaled breath analysis, a simple tool to study the pathophysiology of obstructive sleep apnoea

“…In contrast, two studies by the same group demonstrated that FE NO levels were higher in OSA compared only to non-obese healthy volunteers [5,23]. FE NO A recent study concluded that FE NO has only limited clinical potential in the screening of sleep disordered breathing (SDB) [41], however a composite index including BMI, age, carboxy-haemoglobin saturation, FEF 50 /FIF 50 , neck circumference and FE NO was predictive for OSA [42]. In children, both OSA and non-OSA subjects, habitual snoring appears to be associated with higher FE NO levels [31].…”

Development and validation of a simple-to-use clinical nomogram for predicting obstructive sleep apnea

“…Besides, our study also had some advantages such as using LASSO regression for analyzing clinical factors, 10-fold subjects than previous study and had validation group. Other studies also used clinical nomograms to calculate AHI and even estimate median survival time/event-free survival [7, 22]. We will also extend the usage of nomograms in OSA in further prospective studies.…”

A Clinical Prediction Formula for Apnea-Hypopnea Index

“…Sleep apnea, despite being the most common reason for EDS, was not considered to be a useful clinical feature for detecting OSAS in patients because 30 to 50% of the society claim moderate to sleepiness [ 1 , 2 ]. In addition, other sleep disorders and diseases may cause EDS.…”

“…However, in-lab PSG's limited availability, its high cost, and time- and labor-consuming nature are its disadvantages. The waiting lists of sleep clinics for PSG are quite long, and it is difficult to perform PSG on all patients suspected of OSAS [ 2 ]. Thus, many studies that aim to diagnose OSAS via clinical findings and easily applicable tests have been carried out.…”