Water Sorption and Structural Properties of Human Airway Mucus in Health and Muco-Obstructive Diseases.

Muco-obstructive diseases change airway mucus properties, impairing mucociliary transport and increasing the likelihood of infections. To investigate the sorption properties and nanostructures of mucus in health and disease, we investigated mucus samples from patients and cell cultures (cc) from healthy, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) airways. Atomic force microscopy (AFM) revealed mucin monomers with typical barbell structures, where the globule to spacer volume ratio was the highest for CF mucin. Accordingly, synchrotron small-angle X-ray scattering (SAXS) revealed more pronounced scattering from CF mucin globules and suggested shorter carbohydrate side chains in CF mucin and longer side chains in COPD mucin. Quartz crystal microbalance with dissipation (QCM-D) analysis presented water sorption isotherms of the three types of human airway mucus, where, at high relative humidity, COPD mucus had the highest water content compared to cc-CF and healthy airway mucus (HAM). The higher hydration of the COPD mucus is consistent with the observation of longer side chains of the COPD mucins. At low humidity, no dehydration-induced glass transition was observed in healthy and diseased mucus, suggesting mucus remained in a rubbery state. However, in dialyzed cc-HAM, a sorption-desorption hysteresis (typically observed in the glassy state) appeared, suggesting that small molecules present in mucus suppress the glass transition.

[Task Force Dyspnoe unit (DU)]. / Task Force Dyspnoe Unit (DU).

Acute dyspnoea is one of the most common internal medicine symptoms in the emergency department. It arises from an acute illness or from the exacerbation of a chronic illness. Symptom-related emergency structures and corresponding structural guidelines already exist in the stroke and chest pain units for dealing with the leading symptoms of acute stroke and acute chest pain. These are lacking in Germany for the key symptom of dyspnoea, although the benefits of these structures have already been proven in other countries. The German Society for Pneumology and Respiratory Medicine (DGP) has now set up a task force together with the Association of Pneumology Clinics (VPK), in order to deal with the topic and develop appropriate structural guidelines for such "dyspnoea units" in Germany. At the end of the process, the certification of such units at German hospitals is optional.

Reliability of respiratory event detection with continuous positive airway pressure in moderate to severe obstructive sleep apnea - comparison of polysomnography with a device-based analysis.

PURPOSE: Monitored polysomnography (PSG) is considered the gold standard technique to diagnose obstructive sleep apnea (OSA) and titrate continuous positive airway pressure (CPAP), the accepted primary treatment method. Currently, the American Academy of Sleep Medicine (AASM) considers automatic PAP therapy initiation at home comparable to laboratory titration and recommends telemonitoring-guided interventions. Advanced CPAP devices evaluate and report the residual apnea-hypopnea index (AHI). However, in order to control the effectiveness of the prescribed therapy outside of a PSG setting, the automatic event detection must provide reliable data. METHODS: A CPAP titration was performed in the sleep laboratory by PSG in patients with OSA. The residual event indices detected by the tested device (prismaLine, Loewenstein Medical Technology) were compared to the manually scored PSG indices. Results of the device (AHIFLOW) were compared according to the AASM scoring criteria 1A (AHI1A, hypopneas with a flow signal reduction of ≥ 30% with ≥ 3% oxygen reduction and/or an arousal) and 1B (AHI1B, hypopneas with a flow signal decrease by ≥ 30% with a ≥ 4% oxygen desaturation). RESULTS: In 50 patients with OSA, the mean PSG AHI1A was 10.5 ± 13.8/h and the PSG AHI1B was 7.4 ± 12.6/h compared to a mean device AHIFlow of 8.4 ± 10.0/h. The correlation coefficient regarding PSG AHI1A and AHIFlow was 0.968. The correlation regarding central hypopneas on the other hand was 0.153. There were few central events to be compared in this patient group. CONCLUSION: The device-based analysis showed a high correlation in the determination of residual obstructive AHI under therapy. The recorded residual respiratory event indices in combination with the data about leakage and adherence of the studied device provide reliable information for the implementation and follow-up of CPAP therapy in a typical group of patients with OSA. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT04407949, May 29, 2020, retrospectively registered.

Non-invasive Ventilation: Effect of Vented and Non-vented Exhalation Systems on Inspiratory CO2 and O2 Concentrations, Ventilation, and Breathing Pattern.

INTRODUCTION: To increase CO2 elimination and to reduce work of breathing in hypercapnic patients, non-invasive ventilation (NIV) can be applied via mask either with non-vented CO2 exhalation systems or with vented systems with leak port. The effect of the exhalation system on CO2 rebreathing in the mask and total gas exchange remains widely unknown. Aim of this study was to compare the exhalation systems in terms of inspiratory O2 and CO2 concentrations, breathing patterns and gas exchange. METHODS: We prospectively examined 10 healthy subjects and 10 hypercapnic patients with both exhalation systems. O2 and CO2 were measured in the nose, in the mask, and in the ventilation circuit, and respiratory rate, tidal volume, and transcutaneous capnometry (PtcCO2) were recorded during the experiments. RESULTS: Using the non-vented system, CO2 concentrations in the mask were significantly higher in both subject groups, and PtcCO2 values in the patient group increased up to 3.6 mmHg compared to the vented system (p = 0.011). O2 concentrations increased with higher O2 flow rates, but were significantly lower in the vented settings in both groups. No effect in breathing pattern could be demonstrated during the measurement time. CONCLUSION: Using NIV, the chosen exhalation system influences CO2 and O2 concentrations under the mask, CO2 rebreathing from the mask and could influence the effectiveness of the ventilation support with regards to hypercapnia treatment. To compensate for relevant hypoxia, the O2 supplementation must be set up to a sufficient level under a vented system.

Telehealth and its implementation in respiratory sleep medicine.

PURPOSE OF REVIEW: The COVID-19 pandemic has clearly demonstrated that the technological progress in digitization is also essential for the medical sector. In the field of sleep-disordered breathing, the novel eHealth methods already do offer smart solutions for currently insufficiently addressed problems. RECENT FINDINGS: In general, the potential of telemedicine tools can be focused on three basic aspects: interaction between clinicians, interaction between clinician and patient, and interaction between patient and the mobile health technology. The pandemic situation resulted in a rapid development of reimbursement for telehealth services. In recent years, evidence on the positive benefits of using telemedicine-based support as part of respiratory therapy follow-up is increasing. It is important to consider patient groups, telemedicine methodology, type of intervention, and targeting criteria in all studies conducted. SUMMARY: Given the scarcity of resources for leading common diseases, we must keep an eye on the new digitization concepts in respiratory medicine care. It must be implemented precisely, cost-effectively, and also more connecting between sectors and disciplines and at eye level with our patients. By means of patient engagement systems, an important part of modern precision medicine can be established. Digital support systems are valuable for supporting medical staff. They are not meant to replace medical staff but to facilitate their work and improve its quality.

Effects of endobronchial coils for endoscopic lung volume reduction on sleep in COPD patients with advanced pulmonary emphysema.

PURPOSE: Treatment of advanced pulmonary emphysema with endobronchial coils can improve clinical outcomes like quality of life (QOL). Yet, patients with chronic obstructive pulmonary disease (COPD) are also known to suffer from reduced sleep quality. The effect of coil therapy on sleep has not yet been investigated. The primary aim of this study was to investigate sleep efficiency before and after coil treatment. Secondly, we investigated the effects on nocturnal breathing pattern, QOL, and physical activity. METHODS: Polysomnography (PSG) testing was performed before (T0), 6 month after (T3), and 12 months after (T4) treatment with endobronchial coils. Further examinations included QOL by St George's Respiratory Questionnaire (SGRQ) and COPD assessment test (CAT), and physical activity using an accelerometer for 1 week after each visit. RESULTS: Of 21 patients, 14 completed the study: 6 women; mean age 58.0 ± 4.9 years; BMI 22.6 ± 4.6 kg/m2; FEV1 28.6 ± 7.1% predicted; residual volume (RV) 278.2 ± 49.4% predicted. Sleep efficiency did not vary between baseline and follow-up examinations (T0 69.0 ± 15.8%; T3 70.9 ± 16.0%; T4 66.8 ± 18.9%). Non-REM respiratory rate decreased compared to baseline (T0 19.4 ± 3.9/min; T3 17.8 ± 3.5/min; T4 17.1 ± 3.1/min (p = 0.041; p = 0.030) and QOL improved meeting the minimal clinically important difference (MCID) (SGRQ, T3 -12.8 units; T4 -7.1 units; CAT: T3 -5.6 units; T4 -3.4 units). No increase in physical activity was recorded (light activity T0 31.9 ± 9.9; T3 30.8 ± 16.9; T4 26.3 ± 10.6 h/week). CONCLUSIONS: Treatment with endobronchial coils did not influence objectively measured sleep quality or physical activity, but reduced nocturnal breathing frequency and improved QOL in severe emphysema patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02399514, First Posted: March 26, 2015.

Effects of continuous positive airway pressure therapy on daytime and nighttime arterial blood pressure in patients with severe obstructive sleep apnea and endothelial dysfunction.

PURPOSE: A nocturnal non-dipping or rise in blood pressure (BP) is associated with poor cardiovascular outcome. This study aimed to test whether continuous positive airway pressure (CPAP) therapy can reduce nocturnal BP and normalize the 24-h BP profile in patients with severe obstructive sleep apnea (OSA) and erectile dysfunction as a surrogate for endothelial dysfunction (ED). PATIENTS AND METHODS: Eighteen consecutive patients with OSA and ED on stable antihypertensive medication (age 55.8 ± 9.5 years, body mass index 35.5 ± 3.8 kg/m2, apnea-hypopnoea index 66.1 ± 27.4/h) were treated with CPAP for 6 months (average daily use 5.8 ± 2.3 h). Twenty-four hour BP recordings were performed using a portable monitoring device. Rising was defined as an increase, whereas non-dipping was defined as a fall in nocturnal BP of less than 10% compared to daytime values. Serum noradrenaline levels as markers of sympathetic activity were measured at baseline and at 6 month follow up. RESULTS: Compared to baseline, nocturnal systolic and diastolic BP were significantly reduced after CPAP therapy (128.5 ± 14 to 122.9 ± 11 mmHg, p = 0.036; 76.2 ± 9 to 70.5 ± 5 mmHg, p = 0.007). The frequency of non-dipping and rising nocturnal systolic BP, as well as mean nocturnal heart rate, was reduced after CPAP treatment (73 to 27%, p = 0.039; 20 to 7%, p = 0.625; from 81.5 ± 10 to 74.8 ± 8 beats per minute p = 0.043). Serum levels of noradrenaline were significantly lower after CPAP therapy (398 ± 195 ng/l vs. 303 ± 135 ng/l, p = 0.032). CONCLUSION: In patients with severe OSA and clinically apparent ED, CPAP therapy was associated with a decrease in nocturnal BP and serum noradrenaline levels, as well as a normalization of the 24-h BP profile.

Telemedicine Improves Continuous Positive Airway Pressure Adherence in Stroke Patients with Obstructive Sleep Apnea in a Randomized Trial.

BACKGROUND: The prevalence of obstructive sleep apnea (OSA) is very high in stroke patients, whereas the acceptance of positive airway pressure (PAP) therapy is low. Although telemedicine offers new options to increase acceptance, effective concepts and patient groups are not yet known. OBJECTIVE: The aim of this study was to investigate the effect of a telemedicine concept consisting of telemonitoring and support when usage time drops. METHODS: PAP naive stroke patients with apnea-hypopnea index (AHI) >15 were randomized in a prospective parallel design comparing home therapy with standard care (SC) as opposed to telemedicine care (TC) over a period of 6 months. The TC group received a standardized phone call to offer help and advice if the average weekly usage of PAP fell below 4 h/night. RESULTS: Eighty patients were included, 5 were lost to follow-up, 75 (20 females, age: 57.0 ± 9.9, body mass index: 30.9 ± 6.0 kg/m2, AHI: 39.4 ± 18.6) were evaluated. While inpatient usage was similar in both groups, a significant difference was identified after 6 months of receiving home therapy (TC: 4.4 ± 2.5 h, SC: 2.1 ± 2.2 h; p < 0.000063). On average, 4.7 ± 3.1 interventional phone calls were needed (173 calls in total, ranging from 0 to 10 calls per patient), primarily for the purpose of motivation (61.3%), mask problems (16.2%), nasopharyngeal complaints or humidification issues (11.2%), and technical questions (10.6%). Sleepiness (Epworth Sleepiness Scale [ESS]) differed significantly (TC: 3.7 + 3.2, SC: 6.1 + 4.1; p = 0.008), as well as systolic blood pressure, which was available in a subgroup of 55 patients (TC: 129.5 + 15.2 mm Hg, SC: 138.8 + 16.1 mm Hg; p = 0.034). CONCLUSION: A concept of telemonitoring and short telephone calls from the sleep lab raised PAP therapy adherence significantly in a group of stroke patients with moderate to severe OSA.

COMET: a multicomponent home-based disease-management programme versus routine care in severe COPD.

The COPD Patient Management European Trial (COMET) investigated the efficacy and safety of a home-based COPD disease management intervention for severe COPD patients.The study was an international open-design clinical trial in COPD patients (forced expiratory volume in 1 s <50% of predicted value) randomised 1:1 to the disease management intervention or to the usual management practices at the study centre. The disease management intervention included a self-management programme, home telemonitoring, care coordination and medical management. The primary end-point was the number of unplanned all-cause hospitalisation days in the intention-to-treat (ITT) population. Secondary end-points included acute care hospitalisation days, BODE (body mass index, airflow obstruction, dyspnoea and exercise) index and exacerbations. Safety end-points included adverse events and deaths.For the 157 (disease management) and 162 (usual management) patients eligible for ITT analyses, all-cause hospitalisation days per year (mean±sd) were 17.4±35.4 and 22.6±41.8, respectively (mean difference -5.3, 95% CI -13.7 to -3.1; p=0.16). The disease management group had fewer per-protocol acute care hospitalisation days per year (p=0.047), a lower BODE index (p=0.01) and a lower mortality rate (1.9% versus 14.2%; p<0.001), with no difference in exacerbation frequency. Patient profiles and hospitalisation practices varied substantially across countries.The COMET disease management intervention did not significantly reduce unplanned all-cause hospitalisation days, but reduced acute care hospitalisation days and mortality in severe COPD patients.

A New Tool for Transbronchial Cryobiopsies in the Lung: An Experimental Feasibility ex vivo Study.

BACKGROUND: Transbronchial cryobiopsy (TBCB) is a minimally invasive procedure to establish a diagnosis of interstitial lung disease though with the disadvantage that samples have to be extracted together with the bronchoscope. OBJECTIVES: The aim of the present study was to evaluate the feasibility of a new cryoprobe with which biopsy samples can be obtained through the working channel of the flexible bronchoscope. METHODS: The feasibility of obtaining transbronchial specimens with TBCB was tested and the technique was compared to transbronchial forceps biopsy (TBFB) in a prospectively randomized ex vivo animal study using a standard flexible bronchoscopy technique. The rate of successful biopsies and the duration of the sampling procedure were recorded for both methods. Size and quality of the biopsies were histologically evaluated and measured. RESULTS: Biopsy samples could be obtained in 93.3% of TBCB and in 79.0% of TBFB procedures (p = 0.182). Sampling procedure time did not differ in any clinically relevant manner between the two methods. The mean specimen area of TBCB samples was significantly higher compared to that of TBFB samples (8.08 ± 5.80 vs. 2.61 ± 2.14 mm2; p < 0.0001). TBCB specimens showed less artifacts and a significantly higher percentage of alveolar tissue (53.57 vs. 25.42%; p = 0.0285) than TBFB specimens. CONCLUSIONS: It is feasible to retrieve TBCB samples of good quality and size with the new mini cryoprobe through the working channel of the bronchoscope, while the bronchoscope remains within the central airways throughout the whole procedure. Further studies are necessary to evaluate the safety and efficacy in an in vivo setting.

Effect of APAP and heated humidification with a heated breathing tube on adherence, quality of life, and nasopharyngeal complaints.

PURPOSE: Positive airway pressure (PAP) therapy adherence can be affected by rhinitis sicca and xerostomia complaints. Additional heated humidification (HH) is the appropriate method when such complaints arise. The aim of this study was to determine if HH with a supplementary heated breathing tube can increase adherence, reduce subjective nasopharyngeal complaints (NPC), and improve sleepiness (ESS: Epworth Sleepiness Scale) and quality of life (FOSQ: Functional Outcome of Sleep Questionnaire). METHODS: We subdivided 72 obstructive sleep apnea (OSA) patients into two groups before therapy initiation. The NPC risk group consists of subjects with NPC and the low-risk group without. The risk group was identified by a score of >9 in a 5-item 25-point NPC questionnaire and pathological ESS. All patients were eligible for automatic CPAP devices (APAP), which were randomly configured with or without HH during 6 weeks. RESULTS: The adherence differences with and without HH were not significant in the NPC risk group (330 ± 103 vs. 281 ± 118 min/night) and in the low-risk group (330 ± 116 vs. 321 ± 89). NPC and ESS scores in the risk group were both significantly reduced with HH. Daily function (FOSQ) in the risk group was significantly improved with HH (90.0 ± 11.9 vs. 82.0 ± 12.0 (p < 0.05)). CONCLUSION: HH showed a tendency to improve APAP adherence. The adherence in both groups was quite high, and for that reason, it is difficult to show a statistically significant effect. A differentiation into NPC risk groups before starting PAP treatment is useful. HH reduces side effects and sleepiness and improves quality of life in an NPC risk group.

Transbronchial Catheter Aspiration and Transbronchial Needle Aspiration in the Diagnostic Workup of Peripheral Lung Lesions.

PURPOSE: Increasingly frequent, it is clinically indicated to obtain tissue from a peripheral lung lesion (PLL) to yield a pathological diagnosis. The aim of the present study was to evaluate the diagnostic sensitivity of transbronchial needle aspiration (TBNA) and transbronchial catheter aspiration (TBCA) in addition to transbronchial forceps biopsy (TBB) at conventional bronchoscopy. METHODS: Eligible patients showing a PLL on computed tomography scans were included in the study. In all patients, following TBB, TBNA and TBCA were employed in randomised order under fluoroscopy. RESULTS: Fourty-eight patients were enrolled, of whom 46 patients with 46 PLLs were included in the analysis. The mean ± SD diameter of the PLL was 27.0 ± 13.3 mm. The overall sensitivity for all modalities was 69.6%; PLL ≤20 or >20 and ≤30 mm in diameter showed a sensitivity of 60.0 and 72.2%, respectively. For malignant PLL (n = 33), the combined sensitivity of TBNA + TBCA versus TBB was significantly higher (63.6 vs. 33.3%, p ≤ 0.05), and could not further be improved by TBB. For benign PLL, TBB was superior to TBNA + TBCA (76.9 vs. 38.5%). CONCLUSIONS: TBB, TBNA and TBCA are complementary to one another. Combining the three techniques, even allows transbronchial specimen collection of PLL <3 cm in diameter at conventional bronchoscopy.

Multi-center safety and efficacy study of a negative-pressure intraoral device in obstructive sleep apnea.

BACKGROUND: Intraoral devices, with or without negative oral pressure, can stabilize the oropharynx and reduce obstructive sleep apneas. We tested the hypothesis that treatment with the iNAP® Sleep Therapy System, which applies negative oral pressure through an intra-oral appliance, would reduce the severity of obstructive sleep apnea in a multi-center, prospective, first-night-randomized-order cross-over study. METHODS/PATIENTS: 130 patients fulfilled the entry criteria (age <75, AHI 15-55, BMI <33), and 63 entered the primary endpoint cohort (Total Sleep Time ≥4 h/night on the baseline polysomnogram and an oral negative vacuum time maintained by iNAP® ≥ 4 h/night and total sleep time ≥4 h/night during the first treatment study). 54 patients completed a second treatment sleep study at least 28 days after the first sleep study. RESULTS: Among the primary endpoint cohort (n = 63, age = 53.2 ± 11.3, BMI = 27.1 ± 2.8), 33 patients (52 %; 95 % confidence interval = 40%-64 %, p < 0.001) responded to iNAP treatment according to the Sher criteria (>50 % reduction in AHI and an AHI ≤20 events/hr). The average oxy-hemoglobin saturation increased by 1-2%, and the average percent oxygen desaturation decreased (was less severe) by 1 % while using the iNAP device. The incidence of adverse events, all self-limited, was low. The reduction in the apnea-hypopnea index was durable over the 28-day study. Patients used iNAP on average 5.6 h per night during the study period. CONCLUSION: The iNAP® Sleep Therapy System achieved a durable benefit in more than half the patients with moderate to severe obstructive sleep apnea and may be considered in patients who object to or failed continuous positive airway pressure. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02698059.

The cryo-needle: a new tool for histological biopsies. A feasibility study.

PURPOSE: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure for intrathoracic lymph node biopsies. The newly developed cryo-needle operates in a similar way to the EBUS-TBNA but is able to obtain specimens for histological evaluation. The purpose of this animal study was to evaluate the feasibility, effect, and safety of the cryo-needle biopsies. METHODS: Four EBUS-guided cryo-needle biopsies were obtained from a mediastinal lymph node of a healthy pig. In an open surgery approach, cryo-needle biopsies using activation times of 1, 2, and 3 s (A1/A2/A3) and needle biopsies using a 21-gauge EBUS-TBNA needle were obtained from mesenteric lymph nodes. Cryo-needle biopsies A2 were performed with (A2+) and without (A2-) an oversheath. The size, weight, percentage of lymphatic tissue and artefact-free area of each cryobiopsy were evaluated. Smears were made with the TBNA-needle aspirates to determine the number of lymphocytes per high-power field (HPF). The bleeding duration was measured. RESULTS: We successfully obtained EBUS-guided cryo-needle biopsies. The area and weight of the biopsies A3 and A2+ were significantly larger compared with A1 (1.7 ± 0.8 and 1.4 ± 0.3 vs. 0.9 ± 0.4 mm(2); 5.2 ± 2.4 and 3.4 ± 1.8 vs. 1.5 ± 0.7 mg). The percentage of lymphatic tissue of the cryobiopsies was 90 ± 25 and 98 % of samples were artefact-free. The number of lymphocytes/HPF of TBNA-needle smears was 128 ± 54.3. There was no difference in bleeding duration between the techniques. CONCLUSIONS: The cryo-needle yields large histological specimens of high quality.

Effects of nasal insufflation on arterial gas exchange and breathing pattern in patients with chronic obstructive pulmonary disease and hypercapnic respiratory failure.

High flow nasal insufflations (NI) can improve gas exchange and alleviate dyspnea in patients with acute respiratory failure. In the present study we investigated the effects of high flow nasal insufflations in COPD patients with chronic hypercapnic respiratory failure (HRF). Seventeen patients with severe COPD and HRF were recruited. We delivered a mixture of 20 L/min room air and 2 L/min O(2) through a nasal cannula either into both nostrils (NI) or into one nostril (Partial NI). Respiratory pattern and PaCO(2) responses under NI were compared with low flow oxygen of 2 L/min. High flow nasal insufflations led to a systematic reduction in respiratory rate from 19.8 ± 4.2 at baseline to 18.0 ± 4.7 during NI (p < 0.008) and 18.1 ± 5.2 breaths/min during Partial NI (P < 0.03). The mean group inspiratory duty cycle (T(I)/T(T)) and mean group PaCO(2) remained constant between all experimental conditions. Individual responses to NI were heterogeneous: six patients demonstrated marked reductions in respiratory rate (>20% fall from baseline), another group (n = 6) demonstrated no change in respiratory rate but marked reductions in arterial carbon dioxide of more than 8 mmHg. In conclusion, high flow (20 L/min) nasal insufflations of warm and humidified air during wakefulness for 45 min reduced respiratory rate without deterioration of hypercapnia. Our data indicate that high flow NI improved efficiency of breathing and may be used as an adjunct to low flow oxygen for preventing hypercapnic respiratory failure in severely ill COPD patients.

Asymmetrical nasal high flow ventilation improves clearance of CO2 from the anatomical dead space and increases positive airway pressure.

Positive airway pressure that dynamically changes with breathing, and clearance of anatomical dead space are the key mechanisms of noninvasive respiratory support with nasal high flow (NHF). Pressure mainly depends on flow rate and nare occlusion. The hypothesis is that an increase in asymmetrical occlusion of the nares leads to an improvement in dead-space clearance resulting in a reduction in re-breathing. Clearance was investigated with volumetric capnography in an adult upper-airway model, which was ventilated by a lung simulator with entrained carbon dioxide (CO2) at respiratory rates (RR) of 15-45 min-1 and at 18 min-1 with chronic obstructive pulmonary disease (COPD) breathing patterns. Clearance was assessed at NHF of 20-60 L/min with a symmetrical interface (SI) and an asymmetrical interface (AI). CO2 kinetics visualized by infrared spectroscopy and mathematical modeling were used to study the mechanisms of clearance. At a higher RR (35 min-1) and NHF of 60 L/min, clearance in the upper airway was significantly higher with the AI when compared with the SI (29.64 ± 9.96%, P < 0.001), as opposed to at a lower RR (15 min-1) (1.40 ± 6.25%, P > 0.05), (means ± SD). With COPD breathing, clearance by NHF was reduced but significantly improved with the AI by 45.93% relative to the SI at NHF 20 L/min (P < 0.0001). The maximum pressure achieved with the AI was 6.6 cmH2O and NHF was 60 L/min at the end of expiration. Pressure differences between nasal cavities led to the reverse flow observed in the optical model. Asymmetrical NHF increases dead-space clearance by reverse flow through the choanae and accelerates purging of expired gas via the less occluded nare.NEW & NOTEWORTHY The asymmetrical interface generated reverse flow in the nasal cavities and across the choana, which led to unidirectional purging of expired gas from the upper airways. This accelerated the clearance of anatomical dead space and reduced re-breathing while increased resistance to flow resulted in higher positive end-expiratory pressure (PEEP). These findings are relevant to patients with elevated respiratory rates or with expiratory flow limitations where dead-space clearance by NHF can be substantially reduced.

The contribution of endobronchial ultrasound-guided forceps biopsy in the diagnostic workup of unexplained mediastinal and hilar lymphadenopathy.

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) provides material for the cytological diagnostic workup. To improve the evaluation of unexplained intrathoracic lymphadenopathy, the availability of material for histological evaluation would be desirable. For this purpose, the technique of endobronchial ultrasound-guided mediastinal forceps biopsy (EBUS-guided forceps biopsy) is a potentially good candidate. The aim of the present study was, using simple methodology, to establish the additional diagnostic yield provided by supplemental EBUS-guided forceps biopsy in comparison with EBUS-TBNA alone. METHODS: The data of 50 consecutive patients with mediastinal, lobar, and hilar space-consuming lesions were analyzed. In all patients, immediately following EBUS-TBNA with a 22-gauge needle, a 21-gauge forceps was introduced through the opening created in the bronchial wall and an EBUS-guided forceps biopsy performed. The improvement in the diagnostic yield was determined. The diagnostic yield of the EBUS-guided forceps biopsy in relation to the size of the biopsy specimen and that of the EBUS-TBNA in relation to the cell-block technique were determined. RESULTS: Combining the techniques increased the diagnostic sensitivity of the EBUS-TBNA from 50.0 to 82.0%. EBUS-guided forceps biopsies measuring ≥ 3 mm enabled a specific diagnosis to be established more often than did forceps biopsies <3 mm (90.9% vs. 57.1%). A cell block was prepared in 29 patients. In this case, EBUS-TBNA provided a higher diagnostic yield (65.5% vs. 28.6%) compared to cytology alone. CONCLUSION: EBUS-guided forceps biopsy should be employed for the bronchoscopic diagnosis of intrathoracic lymphadenopathy of unknown etiology.

Prevalence, incidence, and health care utilization of patients with narcolepsy: a population-representative study.

STUDY OBJECTIVES: Previous estimated prevalence of narcolepsy in Europe was 47 patients per 100,000 persons, with a yearly incidence of 0.64-1.37 per 100,000. However, analyses of representative datasets from large cohorts are limited. This study aimed to estimate the population-based diagnostic prevalence and incidence of narcolepsy in Germany and to describe these patients and their health care resource utilization. METHODS: This study used the InGef research database, an anonymized representative dataset of 4 million persons covered by statutory health insurance in Germany. Patients with confirmed narcolepsy diagnoses in 2018 were included. Mid-p-exact tests were used to calculate 95% confidence intervals. Patients with narcolepsy diagnoses and narcolepsy-targeting therapy in 2014-2018 were included to describe health care resource utilization in the year prior to diagnosis. RESULTS: In 2018, diagnostic prevalence was estimated as 17.88 (95% confidence interval 16.45-19.40) and 12-month incidence as 0.79 (0.52-1.15) per 100,000 persons. Forty-six percent of patients were in psycho-behavioral therapeutic treatment and 61% of employees had sick leave days. One in three patients was hospitalized for any cause; 28% received antibiotics. CONCLUSIONS: Diagnostic prevalence was lower, but incidence was consistent with previous reports, although previous estimates may diverge in terms of age/sex distributions. Patients showed a substantial utilization of health care resources, including sick leave and hospitalization. Almost half the patients underwent psycho-behavioral treatment in the year prior to diagnosis, which might indicate a high burden of psychiatric symptoms. The increased use of antibiotics could indicate more frequent infections than in the general population. CITATION: Kallweit U, Nilius G, Trümper D, Vogelmann T, Schubert T. Prevalence, incidence, and health care utilization of patients with narcolepsy: a population-representative study. J Clin Sleep Med. 2022;18(6):1531-1537.

Effect of respiratory rate and size of cannula on pressure and dead-space clearance during nasal high flow in patients with COPD and acute respiratory failure.

Nasal high flow (NHF) is an efficient oxygenation tool for the treatment of respiratory failure. The study investigated the effect of breathing pattern on positive airway pressure and dead-space clearance by NHF. The breathing cycle during NHF was characterized in 26 patients with acute respiratory failure (ARF) and stable COPD and after mechanical ventilation (post-MV) via tracheostomy where also pressure was measured in the trachea. Dead-space clearance was measured in airway models during different breathing patterns. NHF reduced the respiratory rate (RR) and TI/TE through prolonging the TE; the TI/TE ranged between ≤0.5 observed in the COPD patients and ∼1.0 in the ARF patients. NHF via a standard medium-sized cannula interface generated a low-level expiratory pressure proportional to NHF rate and breathing flow; the median generated positive end-expiratory pressure was only 1.71 cmH2O at NHF 45 L/min. The dilution and purging of expired gas from a nasal cavity model were observed to occur at the end of expiration as expiratory flow slowed and the dynamic pressure decreased. The higher RR with shorter end-expiratory period resulted in reduced dead-space clearance by NHF; 20 L/min cleared 43 ± 2 mL at RR 15 min-1 vs. 9 ± 5 mL at RR 45 min-1, P < 0.001, which was increased at higher NHF rate. At lower RR, the clearance was similar between NHF rates 20 and 60 L/min. Higher NHF rates elevate positive airway pressure, and at the increased RR can improve the clearance. This may enhance gas exchange and lead to a reduction in the work of breathing.NEW & NOTEWORTHY During nasal high flow (NHF) an increased breathing frequency, which is commonly observed in acute respiratory failure, can lead to decreased dead-space clearance. Higher NHF rates increase the clearance and reduce the rebreathing which may eventually lower the respiratory rate and the work of breathing. Monitoring of the respiratory rate could be an important indicator of not only the respiratory function but also the NHF rate selection and the therapy efficacy.

Removal of the tracheal tube after prolonged mechanical ventilation: assessment of risk by oscillatory impedance.

BACKGROUND: Decannulation failure is usually due to tracheal obstruction. Prior to decannulation, inspection by the invasive procedure of bronchoscopy that permits morphological evaluation of a tracheal stenosis is standard practice. A non-invasive method enabling the quantification of the airway obstruction that requires little cooperation is measurement of the airway resistance by the forced oscillation technique. OBJECTIVES: The aim of the present study was to define oscillatory impedance thresholds which predict successful decannulation. METHODS: A total of 131 patients were investigated prospectively. Step 1: Following probatory decannulation, measurement of the oscillatory impedance. Step 2: Blinded to the results of the impedance measurement, bronchoscopy-assisted decannulation attempt. The criteria for renewed cannulation were high-grade laryngeal or tracheal obstruction, dyspnea or stridor, or a drop in SaO(2) <90% under O(2) insufflation. STATISTICS: Determination of the ratio tracheal tube remains/tracheal tube removed (TT+/TT-) for every measured value of the oscillatory resistance at 5 Hz (Ros 5 Hz). Determination of specificity and positive predictive value for determined threshold values with respect to TT-. RESULTS: The data of 126 patients were evaluated. TT+ n = 26, TT- n = 100. Decannulation on the basis of bronchoscopy criteria: Specificity and positive predictive value found out for Ros 5 Hz <0.35 kPa/l/s (n = 44) were 1.00 and 1.00, respectively, and for Ros 5 Hz <0.47 kPa/l/s (n = 71) 0.88 and 0.96, respectively. CONCLUSIONS: Measurement of the oscillatory airway resistance represents a practicable method prior to decannulation. Below a value of Ros 5 Hz <0.35 kPa/l/s, bronchoscopy would appear not to be necessary.