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Purpose The study aims to prospectively validate the prognostic value of oximetry alone or combined in a two-step strategy with a questionnaire for the exclusion of obstructive sleep apnea (OSA) in primary care. Methods A total of 140 subjects with suspected OSA were included from 54 participating primary care practices. All subjects completed the Philips questionnaire and underwent one night of oximetry prior to referral to a sleep center. The prognostic value of two strategies was evaluated against the diagnosis of the sleep center as the gold standard: (1) assume OSA and subsequently refer to a sleep center if the oxygen desaturation index (ODI) is ≥ 5 and (2) assume OSA and refer to a sleep center if the Philips questionnaire score is ≥ 55% (regardless of the ODI) or if the Philips questionnaire score is

In this study, the hypercapnic ventilatory response (HCVR) was measured, defined as the ventilation response to carbon dioxide tension (PCO2). We investigated which method, rebreathing or steady-state, is most suitable for measurement of the HCVR in healthy subjects, primarily based on reproducibility. Secondary outcome parameters were subject experience and duration. 20 healthy adults performed a rebreathing and steady-state HCVR measurement on two separate days. Subject experience was assessed using numeric rating scales (NRS). The intraclass correlation coefficient (ICCs) of the sensitivity to carbon dioxide above the ventilatory recruitment threshold and the projected apnoea threshold were calculated to determine the reproducibility of both methods. The ICCs of sensitivity were 0.89 (rebreathing) and 0.56 (steady-state). The ICCs of the projected apnoea threshold were 0.84 (rebreathing) and 0.25 (steady-state). The steady-state measurement was preferred by 16 out of 20 subjects; the differences in NRS scores were small. The hypercapnic ventilatory response measured using the rebreathing setup provided reproducible results, while the steady-state method did not. This may be explained by high variability in end-tidal PCO2. Differences in subject experience between the methods are small., The hypercapnic ventilatory response measured by a rebreathing setup is reproducible, as opposed to a steady-state setup http://ow.ly/yGDg30hStIB

Background: Little is known about the spontaneous recovery of unilateral diaphragm dysfunction (UDD). The aim of the study is to evaluate the recovery rate of UDD and to determine predictors for recovery time. Methods: A retrospective study was conducted in patients with UDD. Spontaneous recovery was measured during follow-up, with a maximum of five years, and was defined as an increase in VC > 400ml. Cox proportional hazard regression analyses were performed to determine predictors for time to spontaneous recovery. Furthermore, the number of respiratory related hospital admissions and pneumonias were obtained. Results: 69 patients (72.5% male, 60 ± 13 years, BMI 29.5 ± 4.2) were included between 1992 and 2018. Spontaneous recovery occurred after 6, 12, 24 and 60 months in respectively 9.0% (95% CI 3.1-14.9), 26.0% (95% CI 16.2-35.8), 35.0% (95% CI 23.2-46.8) and 64.0% (95% CI 48.3-79.7) of the patients. Patients with a traumatic etiology had approximately a 4 till 5 times greater chance of recovery compared to patients with respectively idiopathic (HR 4.08; 95% CI 1.18-14.14) or other causes of UDD (HR 5.47; 95% CI 2.47-12.13). Age, gender, BMI, comorbidities and the severity of UDD did not affect recovery time. Pneumonias and respiratory related hospital admissions were observed in respectively 24.3% and 29.7% of the patients. Conclusion: This study indicates that spontaneous recovery may occur years after onset of UDD. Recovery time depends strongly on underlying etiology. Complications as pneumonia and hospital admissions are common features in these patients.

Obstructive Sleep Apnea (OSA) is recognized as an increasing health risk, leading to daytime sleepiness and various medical conditions, such as hypertension and heart failure. Polysomnography (PSG), the gold standard to diagnose OSA, is a resource-intensive and expensive investigation confined to the hospital.Portable home monitoring, i.e. pulse oximetry, may become an acceptable OSA screening method. The novel nasal pulse oximeter sensor (Xhale Alar) adds the possibility of combining pulse oximetry (SpO2) with airflow analysis by an integrated thermistor, which might increase the diagnostic accuracy.In the Alar pilot study, 39 adults were measured during an overnight PSG recording together with the Alar sensor. This study aims to investigate the additional value of an airflow signal compared to SpO2 analysis in OSA screening. Both time and spectral features were extracted from SpO2 and airflow signals recorded with the Alar sensor. Leave one out cross-validation was used to develop Random Forest models in screening for apnea-hypopnea index (AHI) thresholds 5 and 10. Using both AHI ≥ 5 and AHI ≥ 10 as the diagnostic cutoff, the airflow signal shows respectively an AUC of 89% and 80% compared to 78% and 77% with SpO2 analysis, showing a higher performance using an airflow signal in screening adults for OSA.

The most important function of the lungs is gas exchange. They are able to do so due to a sophisticated balance between ventilation and perfusion. Examples of diseases with a ventilation / perfusion mismatch are acute pulmonary embolism (PE, i.e. blood clots causing (partial) blockage of the pulmonary arteries) and obstructive sleep apnea (OSA, i.e. repetitive breathing stops during sleep due to collapse of the upper airway). In both cases novel diagnostic tools are warranted. The research presented in this thesis focused on the development of novel diagnostic tools using the consequences of ventilation / perfusion mismatches in PE and OSA. For the exclusion of PE at the emergency department, the usability of volumetric capnography and combined measurement of the transfer factor of the lungs for nitric oxide (TLNO) and carbon monoxide (TLCO) were investigated. There was no difference in TLNO / TLCO ratio between subjects with and without PE whereas a novel volumetric capnography derived parameter showed promising results. External validation however showed that this parameter was indeed significantly decreased in subjects with PE but its diagnostic accuracy was too low to allow its use in clinical practice. To be able to find novel strategies to exclude OSA without the need for laborious and expensive tests (e.g. poly(somno)graphy), the oxygen desaturation index (ODI) and the apnea hypopnea index (AHI) were compared in a large polygraphy database. This showed that an ODI < 5 excludes OSA (defined as an AHI ≥ 5) with high certainty. Subsequently, a strategy using a questionnaire and oximetry to exclude OSA in primary care was prospectively validated. As hypothesized, this strategy (i.e. refer to a sleep center if either the oximetry or the questionnaire is aberrant) enabled reliable exclusion of OSA. Another potential tool for the exclusion of OSA was the measurement of exhaled breath profiles using an electronic nose. Though there was a significant relationship between the exhaled breath profiles and the AHI, the profiles could not be used to reliable classify subjects into OSA or non-OSA.

Introduction: Obstructive sleep apnea (OSA) is common, and diagnosis requires expensive and laborious testing to assess the apnea hypopnea index (AHI). We performed an analysis to explore the relationship between the oxygen desaturation index (ODI) as measured with pulse oximetry and the AHI in our large portable monitoring (PM) database to find an optimal cutoff value for the ODI in order to be able to exclude AHI ≥ 5 on PM. Methods: Three thousand four hundred thirteen PM recordings were randomly divided into a training set (N = 2281) and a test set (N = 1132). The optimal cutoff for the ODI to exclude an AHI ≥ 5 on PM was determined in the training set and subsequently validated in the test set. Results: Area under the curve of the ODI to exclude an AHI ≥ 5 on PM was 0.997 in the training set and 0.996 in the test set. In the training set, the optimal cutoff to predict an AHI < 5 was an ODI < 5. Using this cutoff in the test set provided a sensitivity of 97.7%, a specificity of 97.0%, a positive predictive value of 99.2%, and a negative predictive value of 91.4%. Conclusion: An ODI < 5 predicts an AHI < 5 with high sensitivity and specificity when measured simultaneously using the same oximeter during PM recording.

Summary Background The existing screening modalities for pulmonary embolism (PE), such as D-dimer and clinical prediction rules, have low positive predictive values. With its capability to indicate pulmonary vascular abnormalities, the ratio of the transfer factor of the lungs for nitric oxide and the transfer factor of the lungs for carbon monoxide (TL,NO/TL,CO) might be an additional discriminating parameter. Methods Carbon monoxide/Nitric oxide diffusion measurements were performed on unselected patients seen on the emergency department for which due to suspected PE a computed tomography pulmonary angiogram (CTPA) was ordered. Results A total of 28 patients were included, PE was found in 12 on CTPA. Median TL,NO/TL,CO ratio was 4·09 (interquartile range (IQR) 3·83–4·40) in the no PE group versus 4·00 (IQR 3·78–4·32) in the PE group (P = 0·959). Median alveolar volume was 77·1% of predicted in the no PE group versus 71·0% of predicted in the PE group (P = 0·353). Median TL,CO was 75·8% of predicted in the no PE group versus 68·8% of predicted in the PE group (P = 0·120). Median TL,NO was 69·3% of predicted in the no PE group versus 60·5% of predicted in the PE group (P = 0·078). Conclusion The presented data indicate that the TL,NO/TL,CO ratio cannot be used to exclude PE.

Contains fulltext : 165971.pdf (Publisher’s version ) (Open Access) A noncontact mapping system (EnSite) was used for electroanatomical mapping of the bladder simultaneously with pressure flow study in three women with lower urinary tract symptoms. We selected the periods of obvious detrusor activity. Data were processed to remove baseline drift, and an envelope of electrovesicography (EVG) data was created. The correlation coefficient for the correlation between between the EVG envelope and the detrusor pressure (Pdet) was calculated. Bladder geometry was successfully created in all 3 patients. Simultaneous recording of EVG and pressure flow data was successful in 1 patient. Scatter plots were made of the highest correlation coefficient, showing a positive correlation between the Pdet and the envelope, and negative correlation between abdominal pressure (Pabd) and the envelope. Minimal electrical activity could be observed. Significant weak to moderate correlation coefficients were found for the correlations between Pdet and EVG and between Pabd and EVG.

Introduction: detection and quantification of dynamic hyperinflation (DH) in COPD patients in real-life is an intriguing issue, but hard to perform. This study assessed a smart shirt, capable of measuring breathing parameters, as a new diagnostic tool compared to standard lung function equipment. Methods: 31 healthy controls and 11 COPD patients performed basic spirometry, metronome-paced tachypnea (MPT) and an exercise test (either a six-minute-walk or a cardio-pulmonary exercise test (CPET)) wearing the smart shirt (Hexoskin, Carre Technologies, Montreal, Canada) and breathing through a sensor measuring flow. Breathing waveforms produced by the shirt were compared with mobile spirometry (Oxycon Mobile, Care Fusion, San Diego, USA) for its ability to register breathing (e.g. FEV1, IVC and breathing frequency) and detect DH. Results: Moderate-high correlations between the two devices were observed during basic spirometry (median Spearman’s rho for FEV1 (0.81), IVC (0.90) and frequency (0.95)) and during the longer MPT and exercise measurements (range 0.80 - 0.95). The agreement between the shirt and the mobile spirometry with respect to the detection of DH was poor to fair (kappa 0.2-0.3). The smart shirt detected DH more often than the spirometer. Conclusion: the smart shirt is capable of registering breathing patterns and alterations in breathing over time and DH can be detected. Several disturbing factors (such as movement, skin temperature and smart shirt sizing) need to be addressed to improve the detection algorithm. Disclosure: the authors declare no conflict of interest with any company whose equipment has been used.

Introduction: Diagnosing sleep apnea syndrome (SAS) requires expensive and laborious methods to measure the apnea hypopnea index (AHI). This study investigated the correlation between the oxygen desaturation index (ODI) and AHI measured simultaneously during type III portable monitoring (PM) with modern type pulse oximeters in subjects suspected of SAS. If strongly correlated, ODI would be a cheap alternative to exclude SAS. Methods: Data of 3560 successive PM recordings (mean age 53.7±13.5 years, mean BMI 29.6±5.6 kg/m 2 , 70.1% males) were randomly divided into two groups (N=2394 (training set) and N=1166 (test set)). The optimal cutoff for ODI to exclude SAS (AHI Results: From the training set an ODI Conclusion: ODI has high resemblance with AHI when measured simultaneously during PM. Prospective studies on a sole pulse oximetry followed by PM are needed to enable the use of pulse oximetry as a cheap but valid screening tool in patients suspected of sleep apnea syndrome.

Introduction: The prevalence of positional obstructive sleep apnea syndrome (pOSAS) depends on the definition of pOSAS. Cartwright defines pOSAS as Apnea Hypopnea Index (AHI) supine ≥ 2*AHI nonsupine (Sleep 1984; 7:110-114). Mador uses the same criterium with the addition of AHI nonsupine supine - between 10% and 90% of total sleep time (e.g. J Clin Sleep Med 2015; 11(2):139-47). The aim of this study was to retrospectively assess the prevalence of pOSAS in a Dutch sleep center population using the Cartwright, Mador and Dutch criteria. Methods: Data of 2312 successive type III portable monitoring (PM) recordings (mean age 55.5±12.8 years, mean BMI 30.6±5.7 kg/m 2 , 73.5% males) with AHI ≥ 5 were screened for the presence of pOSAS using the Cartwright, Mador and Dutch pOSAS criteria. Results: The prevalence of pOSAS using the Cartwright, Mador and Dutch criteria, subdivided by OSAS severity, is shown in table 1. Conclusion: The prevalence of pOSAS in our Dutch population is low compared with earlier reported values and highly depends on the used definition of pOSAS.

Pulmonary embolism (PE) is a potentially lethal pathology which is hard to exclude without expensive imaging techniques. Recent literature suggests the use of end-tidal PCO2 (PETCO2) as a useful parameter to exclude PE. Analysis of the entire curve of the PCO2 in expired air (volumetric capnography, VCap), contains more information. VCap was performed in subjects seen at the emergency room with D-dimer > 500 µg/L or Wells-score > 4. The association with PE was tested with age, weight, height, Wells score, D-dimer, PETCO2, the calculated anatomic dead space (VDaw/Vt) and the slope of the alveolar phase of the VCap (slope III). Variables with p

The existing screening modalities for pulmonary embolism (PE), such as D-dimer and clinical prediction rules, have low positive predictive values. With its capability to indicate pulmonary vascular abnormalities, the ratio of the transfer factor of the lungs for nitric oxide and the transfer factor of the lungs for carbon monoxide (TCarbon monoxide/Nitric oxide diffusion measurements were performed on unselected patients seen on the emergency department for which due to suspected PE a computed tomography pulmonary angiogram (CTPA) was ordered.A total of 28 patients were included, PE was found in 12 on CTPA. Median TThe presented data indicate that the T

The analysis of the in expired air as a function of the exhaled volume (volumetric capnography) might result in a more specific exclusion tool for pulmonary embolism (PE) in addition to the Wells-score and D-dimer. A novel combination of volumetric capnography parameters () should be decreased in PE and could possibly be used to decrease the number of requested computed tomography pulmonary angiograms (CTPA). Volumetric capnography measurements were performed on consecutive patients seen in the emergency department for which, due to suspected PE (due to increased D-dimer level or Wells-score), a CTPA was ordered. A total of 30 subjects were included, of which in 13 PE was seen on CTPA. Median was 4.36 kPa (IQR 3.92–4.88) in the no PE group versus 4.07 kPa (IQR 3.37–4.39) in the PE group (p = 0.086). Median of the novel parameter was 1.85 min.kPa dl−1 (IQR 1.21–3.00) in the no PE group versus 1.18 min.kPa dl−1 (IQR 0.61–1.38) in the PE group (p = 0.006). Using a threshold for the new parameter of 1.90 min.kPa dl−1 or higher to exclude PE resulted in a negative predictive value of 100% (95% CI: 77%–100%) and would have potentially excluded PE in 47% (95% CI: 26%–69%) of the no PE group without the need for CTPA. This pilot study introduces a novel parameter which is significantly decreased in PE subjects. Future studies regarding validation and addressing aspects such as reproducibility and normalization after treatment are needed to confirm its usability in excluding PE in the emergency department.