Eficacia a medio y largo plazo de la ventilación no invasiva en el síndrome de hipoventilación-obesidad (estudio Pickwick) / Mid- and Long-Term Efficacy of Non-Invasive Ventilation in Obesity Hypoventilation Syndrome: The Pickwick's Study

El proyecto Pickwick es un estudio prospectivo, aleatorizado, abierto y controlado con grupos en paralelo que intenta dar respuesta a los interrogantes del síndrome de hipoventilación-obesidad (SHO), una enfermedad creciente en los países desarrollados. Para ello, pacientes con SHO fueron divididos en pacientes con índice de apneas-hipoapneas (IAH) ≥30 y <30 mediante polisomnografía. El grupo con IAH≥30 se aleatorizó a tratamiento mediante estilo de vida saludable, ventilación no invasiva (VNI) o presión en la vía aérea positiva continua (CPAP). El grupo con IAH<30, a VNI o estilo de vida saludable. Su objetivo ha sido evaluar la eficacia del tratamiento con ventilación VNI, CPAP y estilo de vida saludable (control) a medio y largo plazo en el SHO, analizando como variable primaria la PaCO2 y los días de hospitalización, respectivamente, y como variables operativas el porcentaje de abandonos por razones médicas y mortalidad. Los objetivos secundarios a medio plazo fueron: 1) evaluar la eficacia clínica-funcional, en calidad de vida, en variables polisomnográficas y ecocardiográficas; 2) investigar la importancia de los episodios apneicos y de la leptina en la génesis de la hipoventilación alveolar diurna y el cambio con los diferentes tratamientos; 3) investigar si las alteraciones metabólicas, bioquímicas y disfunción endotelial vascular dependen de la presencia de apneas e hipoapneas, y 4) cambio de marcadores inflamatorios y de daño endotelial con los tratamientos. Los objetivos secundarios a largo plazo fueron: 1) evaluar la eficacia clínico-funcional y en calidad de vida con VNI y CPAP; 2) cambio de la leptina, marcadores inflamatorios y de daño endotelial con los tratamientos; 3) cambio de la hipertensión pulmonar y otras variables ecocardiográficas, así como en la hipertensión arterial e incidencia de episodios cardiovasculares, y 4) frecuencia de abandonos y mortalidad

The Pickwick project was a prospective, randomized and controlled study, which addressed the issue of obesity hypoventilation syndrome (OHS), a growing problem in developed countries. OHS patients were divided according to apnea-hypopnea index (AHI) ≥ 30 and < 30 determined by polysomnography. The group with AHI ≥ 30 was randomized to intervention with lifestyle changes, noninvasive ventilation (NIV) or continuous positive airway pressure (CPAP); the group with AHI < 30 received NIV or lifestyle changes. The aim of the study was to evaluate the efficacy of NIV treatment, CPAP and lifestyle changes (control) in the medium and long-term management of patients with OHS. The primary variables were PaCO2 and days of hospitalization, and operating variables were the percentage of dropouts for medical reasons and mortality. Secondary medium-term objectives were: (I) to evaluate clinical-functional effectiveness on quality of life, echocardiographic and polysomnographic variables; (II) to investigate the importance of apneic events and leptin in the pathogenesis of daytime alveolar hypoventilation and change according to the different treatments; (III) to investigate whether metabolic, biochemical and vascular endothelial dysfunction disorders depend on the presence of apneas and hypopneasm and (IV) changes in inflammatory markers and endothelial damage according to treatment. Secondary long-term objectives were to evaluate: (I) clinical and functional effectiveness and quality of life with NIV and CPAP; (II) changes in leptin, inflammatory markers and endothelial damage according to treatment; (III) changes in pulmonary hypertension and other echocardiographic variables, as well as blood pressure and incidence of cardiovascular events, and (IV) dropout rate and mortality

Validation of the obesity surgery mortality risk score in a multicenter study proves it stratifies mortality risk in patients undergoing gastric bypass for morbid obesity.

BACKGROUND: A scoring system for clinical assessment of mortality risk has been previously proposed for bariatric surgery (Demaria EJ, Portenier D, Wolfe L, Surg Obes Relat Dis. 2007;3:34-40.). The Obesity Surgery Mortality Risk Score (OS-MRS) was developed from a single institution experience of 2075 patients. The current study provides multicenter validation of the value of the OS-MRS. The OS-MRS assigns 1 point to each of 5 preoperative variables, including body mass index>or=50 kg/m2, male gender, hypertension, known risk factors for pulmonary embolism (previous thromboembolism, preoperative vena cava filter, hypoventilation, pulmonary hypertension), and age>or=45 years. Patients with total score of 0 to 1 are classified as 'A' (lowest) risk group, score 2 to 3 as 'B' (intermediate) risk group, and score 4 to 5 as 'C' (high) risk group. METHODS: Prospectively-collected data from 4431 consecutive patients undergoing a primary gastric bypass at 4 bariatric programs recruited to validate the proposed system were analyzed to assess OS-MRS as a means of stratifying surgical mortality risk. RESULTS: There were 33 total deaths for an overall mortality for the validation cohort of 0.7% consistent with published standards. Mortality for 2164 class A patients was 0.2%, for 2142 class B patients was 1.1%, and for 125 class C patients was 2.4%. Mortality was significantly different between each of the class A, B, and C groupings (P<0.05, chi2). Mortality was 5-fold greater in the class B group than in class A. Only 6 patients with all 5 risk factors were identified. Class C patients (n=125, 3% of total cohort) were characterized by a 12-fold greater mortality than the lowest risk group (A) and a disproportionate 9% of all mortalities. CONCLUSION: The OS-MRS was found to stratify mortality risk in 4431 patients from 4 validation centers that were nonparticipants in the original defining cohort study. The score represents the first validated scoring system for risk stratification in bariatric surgery and is anticipated to aid informed consent discussions, guide surgical decision-making, and allow standardization of outcome comparisons between treatment centers.

[Work of breathing in differentiation of various forms of sleep-related breathing disorders]. / Atemarbeit zur Differenzierung verschiedener Formen der schlafbezogenen Atmungsstörung.

BACKGROUND: In contrast to the obstructive sleep apnoea syndrome (OSA) the obesity-hypoventilation syndrome (OHS) is characterised by persistent hypercapnia during the day and predominant hypoventilation during sleep. In this study we wanted to know whether work of breathing (WOB) in a sitting and supine position separates both groups. PATIENTS AND METHODS: OSA population: 20 men, 50.5 +/- 9.2 years, Body Mass Index (BMI: 54.1 +/- 6.9 kg/m2, pO2: 65.6 +/- 6.6 mmHg, pCO2: 40.6 +/- 3.1 mmHg, OHS-group: 14 patients, 13 men age: 53.1 +/- 9.3 years, BMI: 53.1 +/- 9.3 kg/m2, pO2: 51.8 +/- 10.5 mmHg, pCO2: 53.8 +/- 9.2 mmHg. The control group consisted of 10 normal weighted subjects. The intrathoracic pressures were assessed by an oesophageal catheter; at the same time, the minute ventilation (VE) and the breathing frequency (fb) were measured via a pneumotachygraph. The area under the pressure-volume loop was correlated to WOB. After reaching steady state VE, fb, and WOB were determined in sitting and supine position. RESULTS: In the OSA-group the apnoea index (AI) was 48.6 +/- 17.7/h and the respiratory disturbance index (RDI) was 66.3 +/- 19.4/h. The forced expiratory volume (FEV1) was 77.3 +/- 23% pred. and the vital capacity (VC) was 76.3 +/- 18.6% pred.; 7 out of 20 patients suffered from chronic bronchitis. In the OHS-group the AI was 21.5 +/- 19/h and the RDI 44.3 +/- 28.2/h. The majority of OHS patients had an airway obstruction (FEV1: 55.8 +/- 17.5% pred., VC: 58.8 +/- 12.8% pred.); 12 out of 14 patients suffered from chronic bronchitis. Compared to the OSA population WOB in the OHS group was significantly higher both in the sitting (0.67 +/- 0.28 J/I versus 1.04 +/- 0.32 J/I, p < 0.001) and supine positions (1.23 +/- 0.25 J/I versus 1.91 +/- 0.43 J/I, p < 0.001). Compared to the sitting position VE and fb did not change significantly in both groups lying supine. CONCLUSIONS: Compared to the OSA group at the same BMI the WOB of the OHS population was significantly increased in the sitting and supine position. The main reason for these findings may be the increased airway obstruction due to chronic bronchitis. Both populations did not change the breathing patterns during the different positions.

Hypersomnia and periodic breathing. Report of a case and review of the literature.

A patient with hypersomnia and periodic breathing has been studied. Both airflow obstruction and an abnormally of the respiratory control mechanism were implicated in the pathogenesis of the ventilatory arrhythmia. It is suggested that the older terms "Pickwick" syndrome and primary alveolar hypoventilation are abandoned for more descriptive terms, e.g. "hypersomnia with periodic breathing".