Effectiveness of CPAP vs. Noninvasive Ventilation Based on Disease Severity in Obesity Hypoventilation Syndrome and Concomitant Severe Obstructive Sleep Apnea.

RATIONALE: Obesity hypoventilation syndrome (OHS) with concomitant severe obstructive sleep apnea (OSA) is treated with CPAP or noninvasive ventilation (NIV) during sleep. NIV is costlier, but may be advantageous because it provides ventilatory support. However, there are no long-term trials comparing these treatment modalities based on OHS severity. OBJECTIVE: To determine if CPAP have similar effectiveness when compared to NIV according to OHS severity subgroups. METHODS: Post hoc analysis of the Pickwick randomized clinical trial in which 215 ambulatory patients with untreated OHS and concomitant severe OSA, defined as apnoea-hypopnea index (AHI)≥30events/h, were allocated to NIV or CPAP. In the present analysis, the Pickwick cohort was divided in severity subgroups based on the degree of baseline daytime hypercapnia (PaCO2 of 45-49.9 or ≥50mmHg). Repeated measures of PaCO2 and PaO2 during the subsequent 3 years were compared between CPAP and NIV in the two severity subgroups. Statistical analysis was performed using linear mixed-effects model. RESULTS: 204 patients, 97 in the NIV group and 107 in the CPAP group were analyzed. The longitudinal improvements of PaCO2 and PaO2 were similar between CPAP and NIV based on the PaCO2 severity subgroups. CONCLUSION: In ambulatory patients with OHS and concomitant severe OSA who were treated with NIV or CPAP, long-term NIV therapy was similar to CPAP in improving awake hypercapnia, regardless of the severity of baseline hypercapnia. Therefore, in this patient population, the decision to prescribe CPAP or NIV cannot be solely based on the presenting level of PaCO2.

Effectiveness of CPAP vs. Noninvasive Ventilation Based on Disease Severity in Obesity Hypoventilation Syndrome and Concomitant Severe Obstructive Sleep Apnea / El impacto de la terapia de presión positiva de larga duración en el síndrome de hipoventilación-obesidad en función de la gravedad de la enfermedad

Rationale: Obesity hypoventilation syndrome (OHS) with concomitant severe obstructive sleep apnea (OSA) is treated with CPAP or noninvasive ventilation (NIV) during sleep. NIV is costlier, but may be advantageous because it provides ventilatory support. However, there are no long-term trials comparing these treatment modalities based on OHS severity.ObjectiveTo determine if CPAP have similar effectiveness when compared to NIV according to OHS severity subgroups.MethodsPost hoc analysis of the Pickwick randomized clinical trial in which 215 ambulatory patients with untreated OHS and concomitant severe OSA, defined as apnoea-hypopnea index (AHI)≥30events/h, were allocated to NIV or CPAP. In the present analysis, the Pickwick cohort was divided in severity subgroups based on the degree of baseline daytime hypercapnia (PaCO2 of 45–49.9 or ≥50mmHg). Repeated measures of PaCO2 and PaO2 during the subsequent 3 years were compared between CPAP and NIV in the two severity subgroups. Statistical analysis was performed using linear mixed-effects model.Results204 patients, 97 in the NIV group and 107 in the CPAP group were analyzed. The longitudinal improvements of PaCO2 and PaO2 were similar between CPAP and NIV based on the PaCO2 severity subgroups.ConclusionIn ambulatory patients with OHS and concomitant severe OSA who were treated with NIV or CPAP, long-term NIV therapy was similar to CPAP in improving awake hypercapnia, regardless of the severity of baseline hypercapnia. Therefore, in this patient population, the decision to prescribe CPAP or NIV cannot be solely based on the presenting level of PaCO2. (AU)

Introducción: El síndrome de hipoventilación-obesidad (SHO) con apnea obstructiva del sueño (AOS) grave concomitante se trata con CPAPo ventilación no invasiva (VNI) durante el sueño. La VNI es más costosa, pero puede ser beneficiosa porque proporciona soporte ventilatorio; sin embargo, no existen estudios a largo plazo que comparen estas modalidades de tratamiento basándose en la gravedad del SHO.ObjetivoDeterminar si la CPAP tiene una eficacia similar a la VNI según los subgrupos de gravedad del SHO.MétodosAnálisis a posteriori del ensayo clínico aleatorizado Pickwick en el que 215 pacientes ambulatorios con SHO sin tratar y con AOS grave concomitante (definida como un índice de apnea-hipopnea [IAH] ≥ 30 episodios/hora) recibieron tratamiento con VNI o CPAP. En el presente análisis, la cohorte Pickwick se dividió en subgrupos según la gravedad basándose en el grado de hipercapnia diurna al inicio del estudio (PaCO2 de 45-49.9mm Hg o ≥ 50mm Hg). Se compararon las mediciones periódicas de PaCO2 y PaO2 durante los 3 años siguientes entre la CPAP y la VNI entre los dos subgrupos de gravedad. Se realizó un análisis estadístico utilizando un modelo lineal mixto.ResultadosSe analizaron 204 pacientes, 97 en el grupo de VNI y 107 en el grupo de CPAP. Las mejoras lineales de PaCO2 y PaO2 fueron similares entre la CPAP y la NIV según los subgrupos de gravedad en función de la PaCO2.ConclusiónEn los pacientes ambulatorios con SHO y AOS grave concomitante a los que se trató con VNI o CPAP, el tratamiento a largo plazo con VNI resultó similar a la CPAP, en cuanto a la mejora de la hipercapnia en vigilia, independientemente de la gravedad de la hipercapnia de inicio. Por lo tanto, en esta población de pacientes la decisión de prescribir CPAP o VNI no puede basarse exclusivamente en el nivel de partida de PaCO2. (AU)

Primary versus Specialist Care for Obstructive Sleep Apnea: A Systematic Review and Individual-Participant Data-Level Meta-Analysis.

Rationale: Primary care clinicians may be well placed to play a greater role in obstructive sleep apnea (OSA) management. Objectives: To evaluate the outcomes and cost-effectiveness of sleep apnea management in primary versus specialist care, using an individual-participant data meta-analysis to determine whether age, sex, severity of OSA, and daytime sleepiness impacted outcomes. Methods: Data sources were the Cumulative Index to Nursing and Allied Health Literature (CINAHL) database, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid SP, Scopus, ProQuest, U.S. National Institutes of Health Ongoing Trials Register, and ISRCTN registry (inception until 09-25-2019). Hand searching was undertaken. Two authors independently assessed articles and included trials that randomized adults with a suspected diagnosis of sleep apnea to primary versus specialist management within the same study and reported daytime sleepiness using the Epworth Sleepiness Scale (range 0-24; >10 indicates pathological sleepiness; minimum clinically important difference 2 units) at baseline and follow-up. Results: The primary analysis combined data from 970 (100%) participants (four trials). Risk of bias was assessed (Cochrane Tool). One-stage intention-to-treat analysis showed a slightly smaller decrease in daytime sleepiness (0.8; 0.2 to 1.4), but greater reduction in diastolic blood pressure in primary care (-1.9; -3.2 to -0.6 mm Hg), with similar findings in the per-protocol analysis. Primary care-based within-trial healthcare system costs per participant were lower (-$448.51 U.S.), and quality-adjusted life years and daytime sleepiness improvements were less expensive. Similar primary outcome results were obtained for subgroups in both management settings. Conclusions: Similar outcomes in primary care at a lower cost provide strong support for implementation of primary care-based management of sleep apnea.

Long-term Noninvasive Ventilation in Obesity Hypoventilation Syndrome Without Severe OSA: The Pickwick Randomized Controlled Trial.

BACKGROUND: Noninvasive ventilation (NIV) is an effective form of treatment in obesity hypoventilation syndrome (OHS) with severe OSA. However, there is paucity of evidence in patients with OHS without severe OSA phenotype. RESEARCH QUESTION: Is NIV effective in OHS without severe OSA phenotype? STUDY DESIGN AND METHODS: In this multicenter, open-label parallel group clinical trial performed at 16 sites in Spain, we randomly assigned 98 stable ambulatory patients with untreated OHS and apnea-hypopnea index < 30 events/h (ie, no severe OSA) to NIV or lifestyle modification (control group) using simple randomization through an electronic database. The primary end point was hospitalization days per year. Secondary end points included other hospital resource utilization, incident cardiovascular events, mortality, respiratory functional tests, BP, quality of life, sleepiness, and other clinical symptoms. Both investigators and patients were aware of the treatment allocation; however, treating physicians from the routine care team were not aware of patients' enrollment in the clinical trial. The study was stopped early in its eighth year because of difficulty identifying patients with OHS without severe OSA. The analysis was performed according to intention-to-treat and per-protocol principles and by adherence subgroups. RESULTS: Forty-nine patients in the NIV group and 49 in the control group were randomized, and 48 patients in each group were analyzed. During a median follow-up of 4.98 years (interquartile range, 2.98-6.62), the mean hospitalization days per year ± SD was 2.60 ± 5.31 in the control group and 2.71 ± 4.52 in the NIV group (adjusted rate ratio, 1.07; 95% CI, 0.44-2.59; P = .882). NIV therapy, in contrast with the control group, produced significant longitudinal improvement in Paco2, pH, bicarbonate, quality of life (Medical Outcome Survey Short Form 36 physical component), and daytime sleepiness. Moreover, per-protocol analysis showed a statistically significant difference for the time until the first ED visit favoring NIV. In the subgroup with high NIV adherence, the time until the first event of hospital admission, ED visit, and mortality was longer than in the low adherence subgroup. Adverse events were similar between arms. INTERPRETATION: In stable ambulatory patients with OHS without severe OSA, NIV and lifestyle modification had similar long-term hospitalization days per year. A more intensive program aimed at improving NIV adherence may lead to better outcomes. Larger studies are necessary to better determine the long-term benefit of NIV in this subgroup of OHS. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01405976; URL: www.clinicaltrials.gov.

Echocardiographic Changes with Positive Airway Pressure Therapy in Obesity Hypoventilation Syndrome. Long-Term Pickwick Randomized Controlled Clinical Trial.

Rationale: Obesity hypoventilation syndrome (OHS) has been associated with cardiac dysfunction. However, randomized trials assessing the impact of long-term noninvasive ventilation (NIV) or continuous positive airway pressure (CPAP) on cardiac structure and function assessed by echocardiography are lacking.Objectives: In a prespecified secondary analysis of the largest multicenter randomized controlled trial of OHS (Pickwick Project; N = 221 patients with OHS and coexistent severe obstructive sleep apnea), we compared the effectiveness of three years of NIV and CPAP on structural and functional echocardiographic changes.Methods: At baseline and annually during three sequential years, patients underwent transthoracic two-dimensional and Doppler echocardiography. Echocardiographers at each site were blinded to the treatment allocation. Statistical analysis was performed using a linear mixed-effects model with a treatment group and repeated measures interaction to determine the differential effect between CPAP and NIV.Measurements and Main Results: A total of 196 patients were analyzed: 102 were treated with CPAP and 94 were treated with NIV. Systolic pulmonary artery pressure decreased from 40.5 ± 1.47 mm Hg at baseline to 35.3 ± 1.33 mm Hg at three years with CPAP, and from 41.5 ± 1.56 mm Hg to 35.5 ± 1.42 with NIV (P < 0.0001 for longitudinal intragroup changes for both treatment arms). However, there were no significant differences between groups. NIV and CPAP therapies similarly improved left ventricular diastolic dysfunction and reduced left atrial diameter. Both NIV and CPAP improved respiratory function and dyspnea.Conclusions: In patients with OHS who have concomitant severe obstructive sleep apnea, long-term treatment with NIV and CPAP led to similar degrees of improvement in pulmonary hypertension and left ventricular diastolic dysfunction.Clinical trial registered with www.clinicaltrials.gov (NCT01405976).

Long-term clinical effectiveness of continuous positive airway pressure therapy versus non-invasive ventilation therapy in patients with obesity hypoventilation syndrome: a multicentre, open-label, randomised controlled trial.

BACKGROUND: Obesity hypoventilation syndrome is commonly treated with continuous positive airway pressure or non-invasive ventilation during sleep. Non-invasive ventilation is more complex and costly than continuous positive airway pressure but might be advantageous because it provides ventilatory support. To date there have been no long-term trials comparing these treatment modalities. We therefore aimed to determine the long-term comparative effectiveness of both treatment modalities. METHODS: We did a multicentre, open-label, randomised controlled trial at 16 clinical sites in Spain. We included patients aged 15-80 years with untreated obesity hypoventilation syndrome and an apnoea-hypopnoea index of 30 or more events per h. We randomly assigned patients, using simple randomisation through an electronic database, to receive treatment with either non-invasive ventilation or continuous positive airway pressure. Both investigators and patients were aware of the treatment allocation. The research team was not involved in deciding hospital treatment, duration of treatment in the hospital, and adjustment of medications, as well as adjudicating cardiovascular events or cause of mortality. Treating clinicians from the routine care team were not aware of the treatment allocation. The primary outcome was the number of hospitalisation days per year. The analysis was done according to the intention-to-treat principle. This study is registered with ClinicalTrials.gov, number NCT01405976. FINDINGS: From May 4, 2009, to March 25, 2013, 100 patients were randomly assigned to the non-invasive ventilation group and 115 to the continuous positive airway pressure group, of which 97 patients in the non-invasive ventilation group and 107 in the continuous positive airway pressure group were included in the analysis. The median follow-up was 5·44 years (IQR 4·45-6·37) for all patients, 5·37 years (4·36-6·32) in the continuous positive airway pressure group, and 5·55 years (4·53-6·50) in the non-invasive ventilation group. The mean hospitalisation days per patient-year were 1·63 (SD 3·74) in the continuous positive airway pressure group and 1·44 (3·07) in the non-invasive ventilation group (adjusted rate ratio 0·78, 95% CI 0·34-1·77; p=0·561). Adverse events were similar between both groups. INTERPRETATION: In stable patients with obesity hypoventilation syndrome and severe obstructive sleep apnoea, non-invasive ventilation and continuous positive airway pressure have similar long-term effectiveness. Given that continuous positive airway pressure has lower complexity and cost, continuous positive airway pressure might be the preferred first-line positive airway pressure treatment modality until more studies become available. FUNDING: Instituto de Salud Carlos III, Spanish Respiratory Foundation, and Air Liquide Spain.

Primary Care Physicians Can Comprehensively Manage Patients with Sleep Apnea. A Noninferiority Randomized Controlled Trial.

Rationale: General practitioners play a passive role in obstructive sleep apnea (OSA) management. Simplification of the diagnosis and use of a semiautomatic algorithm for treatment can facilitate the integration of general practitioners, which has cost advantages.Objectives: To determine differences in effectiveness between primary health care area (PHA) and in-laboratory specialized management protocols during 6 months of follow-up.Methods: A multicenter, noninferiority, randomized, controlled trial with two open parallel arms and a cost-effectiveness analysis was performed in six tertiary hospitals in Spain. Sequentially screened patients with an intermediate to high OSA probability were randomized to PHA or in-laboratory management. The PHA arm involved a portable monitor with automatic scoring and semiautomatic therapeutic decision-making. The in-laboratory arm included polysomnography and specialized therapeutic decision-making. Patients in both arms received continuous positive airway pressure treatment or sleep hygiene and dietary treatment alone. The primary outcome measure was the Epworth Sleepiness Scale. Secondary outcomes were health-related quality of life, blood pressure, incidence of cardiovascular events, hospital resource utilization, continuous positive airway pressure adherence, and within-trial costs.Measurements and Main Results: In total, 307 patients were randomized and 303 were included in the intention-to-treat analysis. Based on the Epworth Sleepiness Scale, the PHA protocol was noninferior to the in-laboratory protocol. Secondary outcome variables were similar between the protocols. The cost-effectiveness relationship favored the PHA arm, with a cost difference of €537.8 per patient.Conclusions: PHA management may be an alternative to in-laboratory management for patients with an intermediate to high OSA probability. Given the clear economic advantage of outpatient management, this finding could change established clinical practice.Clinical trial registered with www.clinicaltrials.gov (NCT02141165).

Non-invasive Positive Airway Pressure in Obesity Hypoventilation Syndrome and Chronic Obstructive Pulmonary Disease: Present and Future Perspectives.

Obesity hypoventilation syndrome (OHS) is a sleep disorder that has acquired great importance worldwide because of its prevalence and association with obesity leading to increased morbidity and mortality with reduced quality of life. The primary feature is insufficient sleep-related ventilation, resulting in abnormally elevated arterial carbon dioxide pressure (PaCO2) during sleep and demonstration of daytime hypoventilation. There are three main mechanisms that can generate diurnal hypoventilation in obese patients: alteration of the respiratory mechanics secondary to obesity; central hypoventilation secondary to leptin resistance and sleep disorder with sleep hypoventilation and obstructive apnoeas, which can be potentially solved with the use of positive airway pressure: non-invasive ventilation (NIV) and continuous positive airway pressure (CPAP). There are no established guidelines for the treatment of OHS, and only a few randomised controlled trials have been published. In this review, we have gone over the role of positive airway pressure, in particular the mechanisms that produce improvement, ventilatory modes available, clinical applications, technical considerations and future research. In addition, we added a review on NIV efficacy in chronic obstructive pulmonary disease (COPD), both in acute respiratory failure due to exacerbation and mainly in stable setting where more controversy and scientific contributions are coming.

Efecto de la pérdida de peso tras la cirugía bariátrica sobre la función respiratoria y el síndrome de apneas-hipopneas del sueño en mujeres con obesidad mórbida / Effects of weight loss after bariatric surgery on pulmonary function tests and obstructive sleep apnea in morbidly obese women

Introducción: la obesidad afecta a la función respiratoria e incrementa el riesgo de síndrome de apneas-hipopneas del sueño (SAHS). Objetivo: evaluar el efecto de la cirugía bariátrica, en mujeres con obesidad mórbida, sobre la función respiratoria y sobre el índice de apneas-hipopneas (IAH) tras dos años de seguimiento. Métodos: se incluyeron 15 mujeres (índice de masa corporal [IMC] medio 50,52±12,71 kg.m-2, edad media 40,13±10,06 años). Los enfermos fueron analizados en dos fases: previo a la cirugía bariátrica y tras dos años de la misma. En cada visita se valoraron las medidas antropométricas y se realizaron pruebas de función respiratoria consistentes en espirometría, pletismografía, medida de la presión inspiratoria máxima y del índice de tensión-tiempo de los músculos inspiratorios, así como análisis de gases arteriales. Por último, también se efectuó una poligrafía cardiorrespiratoria durante el sueño. Resultados: tras la cirugía bariátrica el IMC disminuyó en 44,07 kg.m-2 (IC 95% 38,32 - 49,81). De igual forma, se observaron incrementos significativos en el volumen espiratorio forzado al primer segundo (FEV1 ) (p<0,01), la capacidad vital forzada (FVC) (p<0,01), el volumen de reserva espiratorio (ERV) (p=0,040), la capacidad funcional residual (FRC) (p=0,009) y la resistencia de las vías aéreas (Raw) (p=0,018). Por otra parte, el IAH (p=0,001) y el índice de desaturación de oxígeno (p=0,001) disminuyeron tras la cirugía. Se observó una correlación significativa entre el grado de pérdida de peso y el incremento del ERV (0,774, p=0,024). Conclusiones: tras dos años desde la cirugía bariátrica se siguen observando mejorías significativas en la función respiratoria y en la gravedad del SAHS. La mejoría del ERV estaría en relación directa con los niveles de peso perdido (AU)

Introduction: obesity impacts on respiratory function and also it acts as a risk factor for obstructive sleep apnea (OSA). Aims: to study the effects of bariatric surgery on pulmonary function tests and on OSA in morbidly obese women over 4 years. Methods: fifteen morbidly obese women (mean body mass index [BMI] 50.52±12.71 kg.m-2, mean age 40.13±10.06 years) underwent pulmonary function tests (PFT) in two opportunities (before and after weight loss surgery). PFT included spirometry, body plethysmography and measure of maximal inspiratory mouth pressure (PImax) and of tension-time index for inspiratory muscles. Also, in both opportunities, resting arterial blood gas tensions were evaluated and a full night sleep register was performed. Results: BMI significantly decreased after bariatric surgery (-44.07 kg.m-2 [CI 95% -38.32 -49.81]). Also, there was a significantly increase in forced expiratory volume in 1 second (FEV1 ) (p<0.01), forced vital capacity (FVC) (p<0.01), expiratory reserve volume (ERV) (p=0.040), functional residual capacity (FRC) (p=0.009) and a decline in airways resistance (Raw) (p=0.018). Concerning sleep registers, apnea hypopnea index (p=0.001) and desaturation index (p=0.001) were also reduced after weight loss. Improve in ERV had a significant correlation with weight loss (r=0.774, p=0.024). Conclusions: pulmonary function tests and apnea hypopnea index improve after bariatric surgery in morbidly obese women. Improvement of ERV is well correlated with weight loss (AU)

[EFFECTS OF WEIGHT LOSS AFTER BARIATRIC SURGERY ON PULMONARY FUNCTION TESTS AND OBSTRUCTIVE SLEEP APNEA IN MORBIDLY OBESE WOMEN]. / EFECTO DE LA PÉRDIDA DE PESO TRAS LA CIRUGÍA BARIÁTRICA SOBRE LA FUNCIÓN RESPIRATORIA Y EL SÍNDROME DE APNEAS-HIPOPNEAS DEL SUEÑO EN MUJERES CON OBESIDAD MÓRBIDA.

INTRODUCTION: obesity impacts on respiratory function and also it acts as a risk factor for obstructive sleep apnea (OSA). AIMS: to study the effects of bariatric surgery on pulmonary function tests and on OSA in morbidly obese women over 4 years. METHODS: fifteen morbidly obese women (mean body mass index [BMI] 50.52 ± 12.71 kg.m-2, mean age 40.13 ± 10.06 years) underwent pulmonary function tests (PFT) in two opportunities (before and after weight loss surgery). PFT included spirometry, body plethysmography and measure of maximal inspiratory mouth pressure (PImax) and of tension-time index for inspiratory muscles. Also, in both opportunities, resting arterial blood gas tensions were evaluated and a full night sleep register was performed. RESULTS: BMI significantly decreased after bariatric surgery (-44.07 kg.m-2 [CI 95% -38.32 - -49.81]). Also, there was a significantly increase in forced expiratory volume in 1 second (FEV1) (p < 0.01), forced vital capacity (FVC) (p < 0.01), expiratory reserve volume (ERV) (p = 0.040), functional residual capacity (FRC) (p = 0.009) and a decline in airways resistance (Raw) (p = 0.018). Concerning sleep registers, apnea hypopnea index (p = 0.001) and desaturation index (p = 0.001) were also reduced after weight loss. Improve in ERV had a significant correlation with weight loss (r = 0.774, p = 0.024). Conclussions: pulmonary function tests and apnea hypopnea index improve after bariatric surgery in mor bidly obese women. Improvement of ERV is well correlated with weight loss.

Introducción: la obesidad afecta a la función respiratoria e incrementa el riesgo de síndrome de apneas-hipopneas del sueño (SAHS). Objetivo: evaluar el efecto de la cirugía bariátrica, en mujeres con obesidad mórbida, sobre la función respiratoria y sobre el índice de apneas-hipopneas (IAH) tras dos años de seguimiento. Métodos: se incluyeron 15 mujeres (índice de masa corporal [IMC] medio 50,52 ± 12,71 kg.m-2, edad media 40,13 ± 10,06 años). Los enfermos fueron analizados en dos fases: previo a la cirugía bariátrica y tras dos años de la misma. En cada visita se valoraron las medidas antropométricas y se realizaron pruebas de función respiratoria consistentes en espirometría, pletismografía, medida de la presión inspiratoria máxima y del índice de tensión-tiempo de los músculos inspiratorios, así como análisis de gases arteriales. Por último, también se efectuó una poligrafía cardiorrespiratoria durante el sueño. Resultados: tras la cirugía bariátrica el IMC disminuyó en 44,07 kg.m-2 (IC 95% 38,32 ­ 49,81). De igual forma, se observaron incrementos significativos en el volumen espiratorio forzado al primer segundo (FEV1) (p < 0,01), la capacidad vital forzada (FVC) (p < 0,01), el volumen de reserva espiratorio (ERV) (p = 0,040), la capacidad funcional residual (FRC) (p = 0,009) y la resistencia de las vías aéreas (Raw) (p = 0,018). Por otra parte, el IAH (p = 0,001) y el índice de desaturación de oxígeno (p = 0,001) disminuyeron tras la cirugía. Se observó una correlación significativa entre el grado de pérdida de peso y el incremento del ERV (0,774, p = 0,024). Conclusiones: tras dos años desde la cirugía bariátrica se siguen observando mejorías significativas en la función respiratoria y en la gravedad del SAHS. La mejoría del ERV estaría en relación directa con los niveles de peso perdido.

The upper airway and obstructive sleep apnea in morbidly obese women.

STUDY OBJECTIVES: We are currently carrying out a study on the changes of the upper airway in morbidly obese women and the relationship of the upper airway with the severity of obstructive sleep apnea syndrome (OSAS). This study is similar to the study by Fogel RB et al, which appeared in Sleep 2003;2:150-5. DESIGN: Patients underwent a cardiorespiratory polygraphic sleep study, respiratory function test (spirometry, plethysmography, arterial blood gas analysis), and computed tomographic studies of the upper airway. PATIENTS: Thirteen morbidly obese women being evaluated for weight-reduction surgery. RESULTS: OSAS was present in all the patients. We found a positive correlation between the uvula diameter and age (r = 0.63, P = .02) and a negative correlation between the area of the oropharynx at the end of maximal expiration and the number of desaturations greater than 4% per hour (r = -0.58, P = .03). In the subgroup of patients with severe OSAS (7 cases), the area of the oropharynx at maximal inspiration had a negative correlation with the apnea-hypopnea index (r = -0.78, P = .03). The resistances of the airway positively correlated with apnea-hypopnea index (r = 0.89, P = .003), apnea index (r = 0.90, P = .03), and desaturation index (r = 0.91, P = .02). The Pao2 had a negative correlation with apnea-hypopnea index (r = -0.63, P = .02), apnea index (r = -0.65, P = .02), and desaturation index (r = -0.66, P = .02). CONCLUSIONS: Our results confirm that, in morbid obese women, airway resistance is higher in those patients with OSAS. We propose that airway resistance and Pao2 can also constitute a good predictor of apnea severity and that a reduction in the cross-sectional area of the airway at the level of the nasopharynx could be related to the severity of OSAS.