Spirometry Reference Equations Including Existing and Novel Parameters.

Introduction: Spirometry is an essential component of pulmonary function testing, with interpretation dependent upon comparing results to normal. Reference equations for mean and lower limit of normal (LLN) are available for usual parameters, including forced vital capacity (FVC), forced expiratory volume in the first second of an FVC maneuver (FEV1), and FEV1/FVC. However, standard parameters do not fully characterize the flow-volume loop and equations are unavailable for the upper limit of normal (ULN). The aim of this study was to develop reference equations for existing and novel spirometry parameters, which more fully describe the flow-volume loop, and to compare these to previously reported equations. Methods: Data from healthy participants in NHANES III was used to derive reference equations for existing and novel spirometry parameters accounting for birth sex, age, height, and ethnicity (Caucasian, Mexican American, Black) for ages 8 to 90 years. An iterative process determined %predicted LLN and ULN. Equations were compared to published reported equations. Results: Reference equations were developed for mean, LLN and ULN for existing and novel spirometry parameters for ages 8 to 90. The derived equations closely match mean values of previously published equations, but more closely fit the LLN. Mexican-American and Caucasian values were similar (within 2%) so they were combined, while Black relative to Caucasian/Mexican-American values were lower for some parameters. Conclusion: These reference equations, which account for birth sex, age, height, and ethnicity for existing and novel spirometry parameters, provide a more comprehensive and quantitative evaluation of spirometry and the flow-volume curve.

Cardiovascular and somatic comorbidities and sleep measures using three hypopnea criteria in mild obstructive sleep-disordered breathing: sex, age, and body mass index differences in a retrospective sleep clinic cohort.

STUDY OBJECTIVES: To describe sex, age, and body mass index (BMI) differences in comorbidities and polysomnography measures, categorized using 3 different apnea-hypopnea index (AHI) criteria in sleep clinic patients with mild obstructive sleep-disordered breathing. METHODS: A retrospective cohort of 305 (64% female) adult sleep clinic patients who underwent full-night in-laboratory polysomnography having been diagnosed with mild sleep-disordered breathing and prescribed positive airway pressure. Effects of sex, age, and BMI on comorbidities and polysomnography measures, including rates of AHI defined by ≥ 3% desaturations (AHI3%), with arousals (AHI3%A), by ≥ 4% desaturations (AHI4%), and by respiratory disturbance index, were evaluated. RESULTS: Sixty-nine (23%), 116 (38%), 258 (85%), and 267 (88%) patients had AHI4%, AHI3%, AHI3%A, and respiratory disturbance index ≥ 5 events/h, respectively. Ninety-day positive airway pressure adherence rates were 45.9% overall and higher in women > 50-years-old (51.2%, P = 0.013) and men (54.5%, P = 0.024) with no difference whether AHI4% or AHI3%A was < 5 or ≥ 5 events/h. Men and women had similar rates of daytime sleepiness (43.3%), anxiety (44.9%), and hypertension (44.9%). Women were more likely to have obesity, anemia, asthma, depression, diabetes, fibromyalgia, hypothyroidism, migraine, and lower rates of coronary artery disease. More patients with AHI4% < 5 events/h had depression, migraines, and anemia, and more patients with AHI4% ≥ 5 events/h had congestive heart failure. Women were more likely to have higher sleep maintenance and efficiency, shorter average obstructive apnea and hypopnea durations, and less supine-dominant pattern. Average obstructive apnea and hypopnea duration decreased with increasing BMI, and average hypopnea duration increased with age. Obstructive apnea duration and obstructive hypopnea with arousal duration decreased with increasing BMI. More women had AHI4% < 5 (81.5% vs 69.1%), AHI3% < 5 (68.7% vs 49.1%), and AHI3%A < 5 events/h (18.5% vs 10.0%). Greater age and higher BMI were associated with higher AHI. CONCLUSIONS: Current AHI criteria do not predict comorbidities or adherence in mild sleep-disordered breathing patients. In this hypothesis-generating descriptive analysis, sex, BMI, and age may all be factors that should be accounted for in future research of mild sleep-disordered breathing patients. Different sleep study measures may weigh differently in calculations of risk for cardiovascular versus somatic comorbidities.

Flow limitation/obstruction with recovery breath (FLOW) event for improved scoring of mild obstructive sleep apnea without electroencephalography.

OBJECTIVE: Apnea/hypopnea index (AHI), especially without arousal criteria, does not adequately risk stratify patients with mild obstructive sleep apnea (OSA). We describe and test scoring reliability of an event, Flow Limitation/Obstruction With recovery breath (FLOW), representing obstructive airflow disruptions using only pressure transducer and snore signals available without electroencephalography. METHODS: The following process was used (i) Development of FLOW event definition, (ii) Training period and definition refinement, and (iii) Reliability testing on 10 100-epoch polysomnography (PSG) samples and two 100-sample tests. Twenty full-night in-laboratory baseline PSGs in OSA patients with AHI with ≥4% desaturations <15 were rescored for FLOW events, traditional hypopneas with desaturations, respiratory-related arousal (RRA) events (hypopneas with arousals and respiratory-effort related arousals) and non-respiratory arousals (NRA). RESULTS: Scoring of FLOW events in 100-epoch samples had good reliability with intraclass correlation (ICC) of 0.91. The overall kappa for presence of events on two sets of 100 sample events was 0.84 and 0.87 demonstrating good agreement. Moreover, 80% of RRA and 8% of NRA were concurrent with FLOW events. Furthermore, 56% of FLOW events were independent of RRA events. FLOW stratifies patients in traditional AHI categories with 50%/8% of AHI with ≥3% desaturations (AHI3) <5 and 12%/63% of AHI3 >5 in lowest/highest tertiles of AHI3 plus FLOW index. CONCLUSIONS: Scoring of FLOW after training is reliable. FLOW scores a high proportion of RRA and many currently unrepresented obstructive airflow disruptions. FLOW allows for stratification within the current normal-mild OSA category, which may better identify patients who will benefit from treatment.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update.

Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features.

Tracheostomy tube manometry: evaluation of speaking valves, capping and need for downsizing.

INTRODUCTION: Readiness to speak is a major problem for many tracheostomized patients. Evaluation for tracheostomy tube capping or speaking valve is often subjective. OBJECTIVES: We first wanted to assess whether there were differences among speaking valves. We developed a care pathway for tracheostomy tube evaluation and management including manometry, which we wanted to evaluate. METHODS: Three different speaking valves were assessed using manometry and measuring dyspnea in 21 patients. Subsequently, 100 consecutive patients referred for tracheostomy tube evaluation in a long-term acute-care rehabilitation hospital were studied using our care pathway with manometry before and after tracheostomy tube changes. RESULTS: Inspiratory pressures differed among the speaking valves. Borg scale was higher among patients with high expiratory pressures. Of the 100 patients, following our care pathway, speech (speaking valve or capping) was recommended for 78 patients with their initial tube, and for 93 patients within 2 days of their initial evaluation. Tracheostomy tube downsizing was recommended in 94 patients. Downsizing led to significant reductions in airway pressures. Capping was initially recommended for 12 patients and for 71 following downsizing. Women had higher pressures than men for the same size tubes. CONCLUSION: Tracheostomy tube manometry is very helpful in objectively guiding recommendations for speaking valve use, capping, and changing tracheostomy tubes. Speech is an early recommendation for most patients.