Formulas to predict continuous positive airway pressure level using a home auto-adjusting device for obstructive sleep apnea treatment.

PURPOSE: To develop equations to predict therapeutic continuous positive airway pressure (CPAPT) based on home-based CPAP titration, including the type of interface used. METHOD: Retrospective study conducted in adult patients with obstructive sleep apnea (OSA) who used home-based autoCPAP titration (AutoSet S10, ResMed®). CPAPT was obtained manually through a visual analysis of autoCPAP data (CPAPV) and automatically using the 95th percentile pressure (CPAPP95). Multiple linear regression and K-fold cross-validation were applied. Independent variables were AHI, neck circumference (NC), BMI, and mask. Two formulas were generated based on mask and the Miljeteig and Hoffstein formula. RESULTS: We included 702 patients (174 women), median age, BMI and AHI of 58 years, 32 kg/m2 and 32 ev/h, respectively. Predictors for CPAPv (M1) were BMI, NC, AHI and type of interface (R2: 0.19); and for CPAPP95 (M2), BMI, AHI and mask (R2: 0.09). Error and precision between the formulas and CPAPT were: 0 (CPAPV/CPAPP95), and - 3.2 to 3.2 (CPAPV) and - 4 to 4 cm H2O (CPAPP95). CPAPV was higher with oronasal mask (10 vs. 9 cm H2O, p < 0.01). Accuracy defined as; a difference ± 2 cm H2O between estimated CPAP and CPAPT was greater in M1 than in M2 (79% vs. 64%, p < 0.01). CONCLUSION: In both models, calculated error was close to zero. CPAPV (± 3.2 cm H2O) showed more precision than CPAPP95 (± 4 cm H2O). With M1 (CPAPV), 79% of patients could start CPAP with reasonable accuracy (error of ± 2 cm H2O).

Independent association between hypoxemia and night sweats in obstructive sleep apnea.

PURPOSE: To assess the relationship between hypoxemia during polysomnography (PSG) and patient-reported night sweats (NS). METHODS: This retrospective observational study included adult patients who completed a standardized sleep questionnaire and the Epworth Sleepiness Scale (ESS) before PSG. RESULTS: We included 1397 patients (41% women). The median age was 52 years, 80% had obstructive sleep apnea (OSA) defined as an apnea-hypopnea index (AHI) ≥ 5, and 35% were obese. A total of 245 patients (17.5%) reported NS. Their prevalence was higher among patients with OSA compared to controls (18.9% vs. 12.2%, p < 0.01). In the bivariate analysis, the variables associated with NS were BMI, AHI, hypoxemia (T90 ≥ 2.5% of total recording time plus minimum SO2 < 85%), frequent body movements or awakenings, nightmares, excessive daytime sleepiness (Epworth > 10), nocturia, cardiovascular events, and the use of sedatives or antidepressants. In the multivariate model, the independent predictors of NS were BMI (OR: 1.47, CI 95%: 1.07-2.01, p = 0.016), hypoxemia (OR: 1.87, CI 95%: 1.37-2.60, p = 0.0001), nightmares (OR: 2.60, CI 95%: 1.73-3.80, p < 0.0001), frequent body movements and awakenings (OR: 1.57, CI 95%: 1.16-2.11, p = 0.003 and OR: 1.54, CI 95%: 1.13-2.08, p = 0.005, respectively), and excessive daytime sleepiness (OR: 1.65, CI 95%: 1.24-2.20, p = 0.0007). CONCLUSIONS: In patients with OSA, night sweats were significantly and independently associated with a higher hypoxic burden.

Proposal of a diagnostic algorithm based on the use of pulse oximetry in obstructive sleep apnea.

PURPOSE: The aims of this study were to assess the cut-off values for oxygen desaturation index ≥ 3% (ODI3) to confirm obstructive sleep apnea (OSA) in subjects undergoing polysomnography (PSG) and home-based respiratory polygraphy (RP), and to propose an algorithm based on pulse oximetry (PO) for initial management of patients with suspected OSA. METHODS: This was an observational, cross-sectional, retrospective study. ODI3 was used to classify subjects as healthy (no OSA = AHI < 5 or < 15 events/h) or unhealthy (OSA = AHI ≥ 5 or ≥ 15 events/h). On the PSG or experimental group (Exp-G), we determined ODI3 cut-off values with 100% specificity (Sp) for both OSA definitions. ODI3 values without false positives in the Exp-G were applied to a validation group (Val-G) to assess their performance. A strategy based on PO was proposed in patients with suspected OSA. RESULTS: In Exp-G (PSG) 1141 patients and in Val-G (RP) 1141 patients were included. In Exp-G, ODI3 > 12 (OSA = AHI ≥ 5) had a sensitivity of 69.5% (CI95% 66.1-72.7) and Sp of 100% (CI95% 99-100), while an ODI3 ≥ 26 had a 53.8% sensitivity (CI95% 49.3-58.2) and Sp of 100% (CI95% 99.4-100) for AHI ≥ 15. A high pretest probability for OSA by Berlin questionaire (≥ 2 categories) had a lower diagnostic performance than by STOP-BANG questionnaire ≥ 5 points (AHI ≥ 5: 0.856 vs. 0.899, p < 0.001; AHI ≥ 15: 0.783 vs. 0.807, p 0.026). CONCLUSION: We propose the initial use of PO at home in cases of moderate-to-high pretest probability of OSA. This algorithm considers PO as well as RP and PSG for more challenging cases or in case of doubt.

A novel, simple, and accurate pulse oximetry indicator for screening adult obstructive sleep apnea.

OBJECTIVE: The objective of the study was to develop a multiparametric oximetry indicator (IMp-SpO2) to diagnose obstructive sleep apnea in adults. MATERIAL AND METHOD: This was an observational, retrospective study of diagnostic accuracy. We included adults who had had a diagnostic polysomnography with few artifacts and a total sleep time of at least 180 min in the sleep laboratory. Obstructive sleep apnea (OSA) was defined as an apnea-hypopnea index (AHI) ≥ 5. The database was randomly divided into an experimental (Exp-G) and validation (Val-G) group. The program calculated several parameters of oxygen saturation variability (Par-VarSpO2): (a) oxygen desaturation index (ODI ≥ 3, 4%) and (b) 90, 95, and 97.5 percentiles of both the number of oxygen desaturations ≥ 3 and 4% (P90-97.5 OD3/4 W5-60) and SpO2 standard deviations in moving windows from 5 to 60 min (P90-P97.5 SDSpO2 W5-10). Area under the ROC curve (AUC-ROC), sensitivity, specificity, positive/negative likelihood ratios, and accuracy were calculated. RESULTS: Of 1141 adults included in the study, experimental (571) and validation group (570) were similar (women 47% vs 45%, BMI 27.5 kg/m2 vs 27.2 kg/m2, and AHI 11.7 vs 12, p NS). The IMp-SpO2 developed in the experimental group consisted of a combination of 10 parameters of oxygen saturation variability. The presence of at least one IMp-SpO2 variable had a high diagnostic performance for OSA (sensitivity/specificity/accuracy: Exp-G: 92.8/94/93.2%; Val-G: 93/95.2/93.7%). The IMp-SpO2 AUC-ROC was higher (Exp-G 0.934, Val-G 0.941) than most of the Par-VarSpO2 (0.898-0.929, p < 0.05). CONCLUSION: The IMp-SpO2 showed a > 90% accuracy for OSA diagnosis in adults.

Contribution of pulse oximetry in relation to respiratory flow events in a home-based approach aimed at diagnosing obstructive sleep apnea.

OBJECTIVE: To compare pulse oximetry with manual analysis against all signals of respiratory polygraphy. MATERIAL AND METHODS: This retrospective study estimated sensitivity (S), specificity (Sp) and positive/negative likelihood ratio (LR+/-) of the oxygen desaturation index (ODI-test) and apnea-hypopnea index (AHI-reference). RESULTS: 3854 patients (61.5% men) were included. Age, BMI, Epworth sleepiness scale and AHI were: 55 years (44-65), 30.9kg/m2 (27-36), 7 points (4-11), and 14 events/hour (6-25), respectively. 18% showed an AHI <5 events/hour, 34% = 5 and <15, 27% = or > 15 and < 30, and 31% > 30. The S, Sp, and LR+/- of ODI for AHI = 5 events/hour was 93%, 92%, 12 and 0.08 with an accuracy of 93%. For AHI = 15 events/hour, the values were: S 94%, Sp 94%, LR+ 15 and LR- 0.06 and 94% accuracy (r(2) Spearman: 0.92). CONCLUSION: In a population at a high risk for OSA, home-based pulse oximetry had a diagnostic accuracy > 90% when is compared against all respiratory signals obtained from simplified home sleep testing.

Indication of CPAP without a sleep study in patients with high pretest probability of obstructive sleep apnea.

OBJECTIVE: To evaluate the performance of clinical criteria (CC) for diagnosis and initiation of empirical treatment with continuous positive airway pressure (CPAP) in patients with suspected obstructive sleep apnea (OSA) compared with the treatment decision based on sleep studies (polysomnography or respiratory polygraphy), guidelines, and experience of participating physicians. METHODS: This was a simulated intention-to-treat study in a retrospective (G1) and prospective (G2) cohort. Four observers (two per group) called CC1 and CC2 reviewed the sleep questionnaires and indicated CPAP if the patients presented snoring, frequent apneas (≥ 3-4/week), body mass index (BMI) > 25 kg/m2, sleepiness (Epworth > 11), or tiredness (at least 3-4 times per week) and some comorbidity (hypertension, coronary/cerebrovascular event, diabetes). Ten independent observers formed two groups of five (FD1 and FD2) and were blinded to each other's opinion. These observers in FD1 and FD2 decided CPAP treatment based on guidelines of the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) or guidelines of the American Academy of Sleep Medicine (AASM) and factored in their own opinion. Sensitivity (S), specificity (Sp), and positive/negative likelihood ratios (LR+/-) were calculated with the test method: CC1/2, and the reference method: majority decision of FD1/2. RESULTS: A total of 653 patients (264 women, 40%) were studied. Median age was 54 years, BMI 28 kg/m2, and apnea hypopnea index (AHI) 16.5 events/h. S ranged from 21 to 25% (p 0.60), Sp 96.1 to 97.6% (p 0.39), and LR+ of clinical criteria 6.4 to 8.9 (p 0.52). CONCLUSION: CPAP indication without a previous sleep study showed a low sensitivity (≅ 22%) but a specificity greater than 95% in patients with high pretest probability for OSA (snoring, report of frequent apneas, BMI > 25 kg/m2 and sleepiness or tiredness plus comorbidity).

CPAP indication based on clinical data and oximetry for patients with suspicion of obstructive sleep apnea: A multicenter trial.

BACKGROUND AND OBJECTIVE: The usefulness of pulse oximetry for the management of obstructive sleep apnea is controversial. The aim of this study was to assess the accuracy for indication of Continuous Positive Airway Pressure (CPAP) treatment in patients with suspected obstructive sleep apnea (OSA) based on clinical and oximetry data as compared to polysomnography (PSG). METHODS: This multicenter observational study involved seven sleep laboratories. Patients with suspicion of OSA who completed a standardized sleep questionnaire and a diagnostic PSG were enrolled. Eight observers logged on to a website independently and blindly. Seven observers only accessed the clinical data, curve and pulse oximetry results (Os-SO2-test method), while the eighth observer had full access to all indicators of PSG (O-PSG-reference method). Once observers assessed the information available on the website, they had to choose between three CPAP treatment options (yes/no/do not know) based on their knowledge and criteria. RESULTS: 411 subjects (228 men), median age 54 years, were available for evaluation. Os-SO2 had lower sensitivity (S), greater specificity (Sp) and positive likelihood ratio (PLR) to prescribe CPAP in patients more symptomatic (Epworth Sleepiness Scale-ESS > 10 or comorbidities) than those with fewer symptoms (ESS < 11 without comorbidities) (S 45-75% versus 45-91%, p 0.028); Sp 93.8-100% versus 68.5-96.6%, p 0.004; PLR > 10 versus 2.9-17, p<0.01). CONCLUSIONS: Due to its low false positive rate, a strategy based on pulse oximetry and clinical data was a consistent tool to indicate CPAP treatment in most symptomatic patients with a suspicion of OSA.

The influence of gender on symptoms associated with obstructive sleep apnea.

BACKGROUND: It has been reported that the clinical expression of obstructive sleep apnea (OSA) may differ in women and men. OBJECTIVE: The objective of this study was to evaluate the influence of gender on reported OSA-related symptoms in a large clinical population of patients. METHODS: The database from the sleep laboratory of a tertiary care center was examined. Adult patients who had undergone a diagnostic polysomnography and completed the Berlin questionnaire, a sleep questionnaire, and the Epworth sleepiness scale were selected. Multiple logistic regression analysis was performed to assess the relationship between OSA-associated symptoms and different potential explanatory variables. RESULTS: The study sample included 1084 patients, median age was 53 years, 46.5% (504) were women, 72.7% (788) had OSA (apnea/hypopnea index ≥ 5), and 31.2% were obese. After adjusting for age, body mass index, and apnea/hypopnea index, men were more likely to report snoring (OR 4.06, p < 0.001), habitual or loud snoring (OR 2.34, p < 0.001; 2.14, p < 0.001, respectively) and apneas (OR 2.44, p < 0.001), than women. After controlling for multiple variables, female gender was an independent predictive factor for reported tiredness (OR 0.57, p 0.001), sleep onset insomnia (OR 0.59, p 0.0035), and morning headaches (OR 0.32, p < 0.001). Reports of excessive daytime sleepiness, nocturia, midnight insomnia, and subjective cognitive complaints were not significantly associated with gender. CONCLUSION: Women with OSA were more likely to report tiredness, initial insomnia, and morning headaches, and less likely to complain of typical OSA symptoms (snoring, apneas) than men.

Can CPAP be indicated in adult patients with suspected obstructive sleep apnea only on the basis of clinical data?

BACKGROUND: There is scarce information about whether the diagnosis of OSA supported only by medical record data can be a useful and reliable tool to initiate a CPAP treatment. OBJECTIVES: The aim of this study is to develop and assess the accuracy of clinical parameters for the diagnosis and prescription of CPAP in patients with suspected OSA. METHODS: Adult patients who underwent polysomnography and completed the Berlin questionnaire, a clinical record, and the Epworth sleepiness scale were included in the study. A situation was simulated in which two blinded and independent observers would be able to indicate CPAP treatment if the patients were snorers with frequent apnea reports (≥3-4 times a week) and overweight (BMI > 25 kg/m(2)) plus one of the following: diurnal symptoms (tiredness after sleeping or at waking time ≥3-4 times a week or Epworth sleepiness scale >11), arterial hypertension, cerebrovascular accident, coronary event, type II diabetes or cardiac arrhythmias (observer 1, clinical criteria) or on the basis of the respiratory disturbance index, significant tiredness (≥3-4 times a week) or sleepiness (Epworth >11) and associated comorbidities (observer 2, reference method). The area under the ROC curve (ABC-ROC), sensitivity, specificity, and likelihood ratios were calculated. RESULTS: Among 516 subjects (72 % men), the median age was 52 years, BMI 28.3 kg/m(2), and RDI 19.7 events/h. The ABC-ROC, sensitivity, specificity, and positive likelihood ratio of the clinical parameters were of 0.64 to 0.65, 31 to 33 %, 97 to 98 %, and 11 to15 respectively. No differences in the diagnostic performance of the clinical criteria were observed between men and women. CONCLUSIONS: These clinical parameters made it possible to indicate CPAP in approximately one third of the population with OSA which would have required it on the basis of their PSG and clinical history. This approach showed high specificity; hence, few patients who did not meet the criteria for CPAP use would have received this treatment.

Accuracy of a novel auto-CPAP device to evaluate the residual apnea-hypopnea index in patients with obstructive sleep apnea.

BACKGROUND: Patients under treatment with continuous positive airway pressure (CPAP) may have residual sleep apnea (RSA). OBJECTIVE: The main objective of our study was to evaluate a novel auto-CPAP for the diagnosis of RSA. METHODS: All patients referred to the sleep laboratory to undergo CPAP polysomnography were evaluated. Patients treated with oxygen or noninvasive ventilation and split-night polysomnography (PSG), PSG with artifacts, or total sleep time less than 180 min were excluded. The PSG was manually analyzed before generating the automatic report from auto-CPAP. PSG variables (respiratory disturbance index (RDI), obstructive apnea index, hypopnea index, and central apnea index) were compared with their counterparts from auto-CPAP through Bland-Altman plots and intraclass correlation coefficient. The diagnostic accuracy of autoscoring from auto-CPAP using different cutoff points of RDI (≥5 and 10) was evaluated by the receiver operating characteristics (ROCs) curve. RESULTS: The study included 114 patients (24 women; mean age and BMI, 59 years old and 33 kg/m(2); RDI and apnea/hypopnea index (AHI)-auto median, 5 and 2, respectively). The average difference between the AHI-auto and the RDI was -3.5 ± 3.9. The intraclass correlation coefficient (ICC) between the total number of central apneas, obstructive, and hypopneas between the PSG and the auto-CPAP were 0.69, 0.16, and 0.15, respectively. An AHI-auto >2 (RDI ≥ 5) or >4 (RDI ≥ 10) had an area under the ROC curve, sensitivity, specificity, positive likelihood ratio, and negative for diagnosis of residual sleep apnea of 0.84/0.89, 84/81%, 82/91%, 4.5/9.5, and 0.22/0.2, respectively. CONCLUSIONS: The automatic analysis from auto-CPAP (S9 Autoset) showed a good diagnostic accuracy to identify residual sleep apnea. The absolute agreement between PSG and auto-CPAP to classify the respiratory events correctly varied from very low (obstructive apneas, hypopneas) to moderate (central apneas).

Consideraciones sobre la carta editorial: Hasta cuándo poligrafía respiratoria vs. polisomnografía / Letter considerations Editorial: "Until when polygraphy respiratory vs. polysomnography "

En la RAMR Vol. 13, N° 2, año 2013, se publica una carta editorial titulada "¿Hasta cuándo poligrafía versus polisomnografía?" Los autores hacen varias observaciones al trabajo recientemente publicado sobre poligrafía respiratoria (PR) por Borsini y col. (RAMR Vol. 13, N° 1, 2013). Algunos conceptos expresados en esta carta me han llevado a escribir esta nota con la finalidad de esclarecer algunos puntos que pueden ser de interés para los lectores

Validation of ApneaLink Ox™ for the diagnosis of obstructive sleep apnea.

OBJECTIVE: The aim of the study was to validate the automatic and manual analysis of ApneaLink Ox™ (ALOX) in patients with suspected obstructive sleep apnea (OSA). METHODS: All patients with suspected OSA had a polysomnography (PSG) and an ALOX performed in the sleep laboratory. For automatic analysis, hypopnea was defined as a decrease in airflow ≥30 % of baseline for at least 10 s plus oxygen desaturation ≥3 or 4 %. While for the manual analysis, hypopnoea was considered when a reduction of airflow ≥30 % of ≥10 s plus oxygen desaturation ≥3 % or increase in cardiac rate ≥5 beats/min were identified or, when only a reduction of airflow ≥50 % was observed. OSA was defined as a respiratory disturbance index (RDI) ≥5. The apnea/hypopnea automatic index (AHI3-a, AHI4-a) and manual index were estimated. Receiver operating characteristics (ROC) analysis and the agreement between ALOX and PSG were performed. RESULTS: Fifty-five patients were included (38 men; mean age, 48.2; median, RDI 15.1; median BMI, 30 Kg/m(2)). The automatic analysis of ALOX under-estimated the RDI from PSG, mainly for the criterion of oxygen desaturation ≥4 % (AHI3-a-RDI, -3.6 ± 10.1; AHI4-a-RDI, -6.5 ± 10.9, p < 0.05). The autoscoring from ALOX device showed a better performance when it was set up to identify hypopneas with an oxygen desaturation criterion of ≥3 % than when it was configured with an oxygen desaturation criterion of ≥4 % (area under the receiver operator curves, 0.87 vs. 0.84). Also, the manual analysis was found to be better than the autoscoring set up with an oxygen desaturation of ≥3 % (0.923 vs. 0.87). The manual analysis showed a good interobserver agreement for the classification of patients with or without OSA (k = 0.81). CONCLUSION: The AHI obtained automatically from the ApneaLink Ox™ using oxygen desaturation ≥3 % as a criterion of hypopnea had a good performance to diagnose OSA. The manual scoring from ApneaLink Ox™ was better than the automatic scoring to discriminate patients with OSA.

How reliable is the manual correction of the autoscoring of a level IV sleep study (ApneaLink™) by an observer without experience in polysomnography?

OBJECTIVE: This study aims to compare the manual correction of the automatic analysis of ApneaLink™ between a skilled observer in the interpretation of sleep studies and a subject trained only in the scoring of ApneaLink™ device. METHODS: Ninety-six subjects performed the ApneaLink™ and polysomnography (PSG) simultaneously in the sleep laboratory. Two blind observers, who were independent from the results of the PSG, performed first the automatic scoring and then the hand correction from the ApneaLink™ device. The scorers of ApneaLink™ represented two physicians with different levels of training (scorer A: 20 years of experience in reading polysomnography plus 3 years of experience in the interpretation of ApneaLink™, scorer B: 1 year of experience in the analysis of ApneaLink™). The interobserver agreement was assessed with the intraclass correlation coefficient (ICC) and kappa statistics. The diagnostic accuracy of the manual analysis ApneaLink™ device was evaluated by the area under the receiver operator curve (AUC-ROC). RESULTS: Ninety patients were included (69 men; mean age, 49.6; median RDI, 13.9; median BMI, 29.3 Kg/m(2)). The ICC between the manual apnea/hypopnea index from ApneaLink™ and the respiratory disturbance index of the PSG for each observer was similar (scorer A, 0.902; CI 95% 0.80-0.95; vs. scorer B, 0.904; CI 95% 0.86-0.94; p = 0.9). The agreement between the observers on the presence or absence of obstructive sleep apnea syndrome (OSAS) was very good (kappa, 0.83; CI 95% 0.69-0.98). The AUC-ROC was similar between the observers (scorer A, 0.88; CI 95% 0.78-0.98; scorer B, 0.83; CI 95% 0.71-0.95; p = 0.5). CONCLUSIONS: The non-expert observer showed a very good agreement with the expert observer on the results of the manual correction of the ApneaLink™ autoscoring. Both observers had similar diagnostic accuracy to identify subjects with OSAS when compared with PSG.

Accuracy of the clinical parameters and oximetry to initiate CPAP in patients with suspected obstructive sleep apnea.

OBJECTIVE: The aim of this study was to assess the accuracy of oximetry and the clinical parameters for the prescription of continuous positive airway pressure (CPAP) in patients with suspected obstructive sleep apnea syndrome (OSAS). METHODS: All participants (135) performed oximetry (WristOx 3100™) and polysomnography (PSG) simultaneously in the sleep laboratory. The patients completed the Epworth sleepiness scale, the Berlin questionnaire, and a clinical history. Two blind independent observers decided to prescribe CPAP according to the results of the PSG (gold standard, observer A), oximetry (alternative method, observer B), and the clinical parameters. The accuracy of observer B on the indication of CPAP, using different cutoff points of the adjusted desaturation index (ADI3 and ADI4), was evaluated by the area under the receiver operating characteristics curve (AUC-ROC). The interobserver agreement for the indication of CPAP was assessed using kappa statistics. RESULTS: One hundred nineteen subjects were included (92 men; mean age, 53; median respiratory disturbance index, 22.6; median BMI, 27.5 kg/m(2)). Depending on the criteria used in oximetry, the sensitivity and specificity of observer B to initiate a CPAP trial ranged from 79.8% to 92.5% and of 92% to 96%, respectively. The best performance for the indication of CPAP was noted with the adjusted O(2) desaturation index ≥ 3% (AUC-ROC, 0.923). The inter-rater agreement for the prescription of CPAP was good (kappa, 0.60 to 0.79). CONCLUSION: This simulated study has shown that the use of oximetry plus clinical data has made it possible to indicate CPAP reliably in nearly 90% of the population with OSAS.

Indication of CPAP in Patients with Suspected Obstructive Sleep Apnea, Based on Clinical Parameters and a Novel Two-Channel Recording Device (ApneaLink): A Pilot Study.

Objective. To evaluate the accuracy and reliability of the medical decision based on the results of the hand scoring from a two-channel recording device (ApneaLink) plus clinical data for the prescription of a CPAP assay in patients with suspected OSA. Methods. 39 subjects were assessed in the sleep laboratory with polysomnography and ApneaLink. The patients completed the Epworth sleepiness scale and a clinical history. Two blinded independent observers decided to prescribe CPAP according to the results of the PSG (gold standard, observer A), ApneaLink (alternative method, observer B), and the clinical parameters. Sensitivity and specificity of observer B on the indication of CPAP were calculated. The interobserver agreement for the indication of CPAP was assessed using kappa statistics. Results. 38 subjects were included (26 men, mean age 47.5, mean RDI 28.7, mean BMI 31.4 kg/m(2)). The prevalence of OSA was 84%. The sensitivity and specificity of observer B to initiate a CPAP trial were 90.6% and 100%, respectively. The interrater agreement for the prescription of CPAP was good (kappa: 0.75). Conclusion. This study has shown that the use of ApneaLink plus clinical data has made it possible to indicate CPAP reliably in most patients with high-clinical pretest for OSA.

Comparison of the automatic analysis versus the manual scoring from ApneaLink™ device for the diagnosis of obstructive sleep apnoea syndrome.

OBJECTIVE: The purpose of this study was to compare the performance of the automated detection versus the manual scoring from the ApneaLink™ device to diagnose obstructive sleep apnoea syndrome (OSAS). METHODS: All participants (96) performed the ApneaLink™ (AL) and polysomnography (PSG) simultaneously in the sleep laboratory. The two recordings were interpreted blindly. The hypopnoea criterion used for the analysis of both automatic and manual ApneaLink™ was a fall in airflow ≥50% of baseline for ≥10 s. The agreement between AL and PSG and the interobserver concordance was calculated. ROC analysis, sensitivity and specificity were assessed for the different ApneaLink™ and OSAS criteria. RESULTS: Ninety patients were included (69 men; mean age, 49.6; median RDI, 13.9; median BMI, 29.3 kg/m(2)). The automatic apnoea/hypopnoea index (AHI-a) showed a lower agreement with the respiratory disturbance index (RDI) than the manual apnoea/hypopnoea (AHI-m) [AHI-a/RDI: intraclass correlation coefficient (ICC) 0.88 versus AHI-m/RDI: ICC 0.91]. The manual scoring (MS) showed a similar sensitivity and a higher specificity than the automatic scoring (AA) for the detection of OSAS, defined as an RDI ≥ 5 (sensitivity and specificity AA and MS: 89%/89%, 60%/86.7%, respectively). The accuracy of the automatic and manual scoring of the AL was similar when OSAS was defined as an RDI ≥ 20 or 30. The ApneaLink™ manual scoring had a very good interobserver agreement (k = 0.86). CONCLUSIONS: The manual scoring of an ApneaLink™ recording was better than the automatic scoring in terms of agreement with RDI and to discriminate patients with OSAS. The hand scoring did not improve the accuracy of automatic scoring in patients with severe OSAS.

Validation of the WristOx 3100 oximeter for the diagnosis of sleep apnea/hypopnea syndrome.

OBJECTIVE: To evaluate the diagnostic accuracy of the Nonin WristOx 3100 and its software (nVision 5.0) in patients with suspicion of sleep apnea/hypopnea syndrome (SAHS). METHODS: All participants (168) had the oximetry and polysomnography simultaneously. The two recordings were interpreted blindly. The software calculated: adjusted O(2) desaturation index [ADI]-mean number of O(2) desaturation per hour of total recording analyzed time of > or = 2%, 3%, 4%, 5%, and 6% (ADI2, 3, 4, 5, and 6) and AT90-accumulated time at SO(2) < 90%. The ADI2, 3, 4, 5, and 6 and the AT90 cutoff points that better discriminated between subjects with or without SAHS arose from the receiver operating characteristic curve analysis. The sensitivity (S), specificity (E), and positive and negative likelihood ratio (LR+, LR-) for the different thresholds for ADI were calculated. RESULTS: One hundred and fifty-four patients were included (119 men, mean age 51, median apnea/hypopnea index [AHI] 14, median body mass index [BMI] 28.3 kg/m(2)). The best cutoff points of ADI were: SAHS = AHI > or = 5: ADI2 > 19.3 (S 89%, E 94%, LR+ 15.5 LR- 0.11); SAHS =AHI > or = 10: ADI3 > 10.5 (S 88%, E 94%, LR+ 15 LR- 0.12); SAHS = AHI > or = 15: ADI3 > 13.4 (S 88%, E 90%, LR+ 8.9, LR- 0.14). AT90 had the lowest diagnosis accuracy. An ADI2 < or = 12.2 excluded SAHS (AHI > or = 5 and 10; S 100%, LR- 0) and ADI3 > 4.3 (AHI > or = 5 and 10) or 32 (AHI > or = 15) confirmed SAHS (E 100%). CONCLUSIONS: A negative oximetry defined as ADI2 < or = 12.2 excluded SAHS defined as AHI > or = 5 or 10 with a sensitivity and negative likelihood ratio of 100% and 0%, respectively. Furthermore, a positive oximetry defined as an ADI3 > 32 (SAHS = AHI > or = 15) had a specificity of 100% to confirm the pathology.

Effect of inhaled salbutamol on dynamic intrinsic positive end-expiratory pressure in spontaneously breathing patients with stable severe chronic obstructive pulmonary disease.

BACKGROUND: The objective was to determine the effect of inhaled salbutamol on PEEPi dyn in spontaneously breathing patients with stable severe chronic obstructive pulmonary disease (COPD). MATERIAL/METHODS: Eleven patients with COPD were studied (mean age: 63 years, average FEV1 0.71 +/- 0.31 L). The patients were evaluated before and after inhaling 400 pg of salbutamol. Spirometry, slow vital capacity, breathing pattern, and PEEPi dyn pre- and post-bronchodilator administration were performed. PEEPi dyn was measured as the difference in esophageal pressure between the onset of inspiratory effort and the point of zero flow. RESULTS: Pre-BD PEEPi dyn fell on average by 56% after inhalation of salbutamol (1.89 +/- 1.24 cm H2O to 0.83 +/- 0.81 cm H2O, p<0.001). This was accompanied by bronchodilation and a reduction of air trapping (FEV1: 0.71 +/- 0.31 L to 0.91 +/- 0.35 L, p<0.001; IC: 1.5 +/- 0.53 L to 1.94 +/- 0.56 L, p<0.001). A significant positive correlation between deltaPEEPi dyn, deltaFEV1 (r=0.64, p<0.05), and deltaIC (r=0.69, p<0.05) was observed. The breathing pattern did not change significantly after bronchodilation. Stepwise multiple regression analysis of pre-BD spirometric and breathing pattern parameters selected IC and Ti/Ttot as the strongest predictors of pre-BD PEEPi dyn (p=0.039 and 0.006, respectively). CONCLUSIONS: The inhalation of 400 microg of salbutamol produced bronchodilation, reduction of air trapping, and a decrease in PEEPi dyn in spontaneously breathing patients with stable severe COPD.

Variation in the duration of arousal in obstructive sleep apnea.

BACKGROUND: The aim of this study was to evaluate the relationship between the duration of arousal and the type, duration and minSaO(2) of apneas/hypopneas, and the time of night and sleep stage when they occurred. MATERIAL/METHODS: We measured the duration of arousals associated with apneas (A) and hypopneas (H) in 10 polysomnographic recording. Arousals were categorized as: 1) Short Electroencephalographic Arousal (SEA: 3-15 s) and 2) Awakenings (>15 s). The dependent variable for multiple logistic regression analysis was duration of arousal (0 = 3-11 s, 1 = >11 s); the independent variables were event (0 = H, 1 = A), event duration (0 = 10-20 s, 1 = >20 s), sleep stage (0 = REM, 1 = NREM 1-2); minSaO(2) (0 = 86%, 1 = <86%) and time of night (0 = at or before 3:00 AM, 1 = after 3:00 AM). RESULTS: We analyzed 1536 apneas and hypopneas. 80.3% had arousal, 61% SEA and 19.3% awakenings. The median duration of arousal was higher in apneas (A: 12 s, H: 9.2 s, p<0.001). The apneas and events >20 s with a minSaO(2) <86% had a higher probability of arousal >11 s (apnea: OR 2.1, p<0.001; events >20 s: OR 1.5, p<0.01; minSaO(2) <86%: OR 1.4, p<0.05). CONCLUSIONS: Arousals were greater in apneas than in hypopneas. Apneas and events >20 s with a minSaO(2) <86% were associated more frequently with arousal >11 s.