ABSTRACT Objective: Identifying significant fibrosis is crucial to evaluate the prognosis and therapeutic interventions in patients with nonalcoholic fatty liver disease (NAFLD). We assessed the performance of acoustic radiation force impulse (ARFI) elastography, APRI, FIB-4, Forns, NFS and BARD scores in determining liver fibrosis in severe obesity. Subjects and methods: A prospective study included 108 patients undergoing bariatric surgery. Liver biopsy specimens were obtained intraoperatively and classified according to the NAFLD Activity Score. Patients were assessed with serological markers and shear wave velocity of the liver was measured with the Siemens S2000 ultrasound system preoperatively. Optimal cut-off values were determined using the area under the receiver operating characteristic curves (AUROC). Results: In the entire cohort prevalence of NAFLD was 80.6%, steatohepatitis 25.9% and significant fibrosis 19.4%. The best tests for predicting significant fibrosis were FIB-4 and Forns scores (both AUROC 0.78), followed by APRI (AUROC 0.74), NFS (AUROC 0.68), BARD (AUROC 0.64) and ARFI (AUROC 0.62). ARFI elastography was successful in 73% of the patients. Higher body mass index (BMI) correlated with invalid ARFI measurements. In patients with BMI < 42 kg/m2, ARFI showed 92.3% sensitivity and 82,6% specificity for the presence of significant fibrosis, with AUROC 0.86 and cut-off 1.32 m/s. Conclusions: FIB-4 and Forns scores were the most accurate for the prediction of significant fibrosis in bariatric patients. Applicability and accuracy of ARFI was limited in individuals with severe obesity. In patients with BMI < 42 kg/m2, ARFI elastography was capable for predicting significant fibrosis with relevant accuracy.

INTRODUÇÃO: A obesidade acarreta uma série de alterações na fisiologia respiratória e no sono. Seu tratamento tem como objetivo a melhora da saúde e da qualidade de vida. OBJETIVO: Avaliar a função pulmonar e o sono em indivíduos obesos mórbidos pré-cirurgia bariátrica. MATERIAIS E MÉTODOS: Participaram deste estudo 38 pacientes, recrutados em dois serviços de cirurgia bariátrica e encaminhados ao Laboratório de Sono da Universidade Nove de Julho, São Paulo, Brasil. Os critérios de inclusão foram: obesos mórbidos, IMC entre 40 kg/m² e 50 kg/m² e IMC entre 35 kg/m² a 39,9 kg/m² se associados a comorbidades. RESULTADOS: A média de idade foi de 42 ± 10, o índice de massa corpórea médio foi de 50,09 ± 7,64. A média da circunferência abdominal foi de 132,48 ±11,07 e 134,31 ± 16,26 e de pescoço foi 42,34 ± 2,08 e 44,48 ± 3,67, respectivamente para mulheres e homens. As pressões máximas inspiratórias foram 57,57 ± 18,93 e 60,6 ± 3,72 e máximas expiratórias 56,63 ± 16,68 e 60 ± 18,52, para mulheres e homens respectivamente. O sono do movimento rápido dos olhos apresentou-se com média de 16,93 ± 13,61 e a saturação mínima da oxi-hemoglobina foi de 79,33 ± 10,26 durante o sono. Em 44,74% dos casos examinados, foram observadas alterações na Escala de Sonolência de Epworth (ESE); e em 76,3% ficou confirmada a presença de síndrome da apneia obstrutiva do sono (SAOS). CONCLUSÃO: Foram observadas alterações nas pressões máximas ventilatórias, na estrutura do sono associadas a considerável dessaturação noturna da oxi-hemoglobina, o que evidencia alta prevalência de SAOS nos pacientes obesos mórbidos.

INTRODUCTION: Obesity causes a series respiratory physiology and sleep changes. Its treatment aims to improve health and quality of life. OBJECTIVE: To evaluate pulmonary function and sleep in morbidly obeses pre-bariatric surgery. MATERIALS AND METHODS: The study had 38 patients recruited at two bariatric surgery services and referred to the Laboratório do Sono da Universidade Nove de Julho (Uninove), Sao Paulo, Brazil. The adopted criteria were: BMI between 40 kg/m² and 50 kg/m² and BMI between 35 kg/m² to 39.9 kg/m² associated comorbidities. RESULTS: Mean age was 42 ± 10, the mean body mass index was 50.09 ± 7.64. The average waist circumference was 132.48 ± 11.07 and 134.31 ± 16.26; the circumference neck was 42.34 ± 2.08 and 44.48 ± 3.67, respectively for women and men. The maximum inspiratory pressures were 57.57 ± 18.93 and 60.6 ± 3.72 and 56.63 ± 16.69 maximal expiratory and 60 ± 18.52 for women and men, respectively. The rapid eye movement sleep presented a mean of 16.93 ± 13.61 and minimum oxy-hemoglobin saturation of 79.33 ± 10.26 during sleep. In 44.74% of the cases studied changes were observed in the Epworth Sleepiness Scale; and in 76.30% the presence of the syndrome of obstructive sleep apnea (OSA) was confirmed. CONCLUSION: We observed changes in maximum pressure ventilation in sleep structure associated with significant nocturnal desaturation of oxy-hemoglobin showing a high prevalence of OSA in morbidly obese patients.