Abstract Objective: Continuous Positive Airway Pressure (CPAP) is the gold standard treatment for OSA. A wide variety of masks are used during CPAP therapy. The aim of the study is to compare polysomnography outcomes during titration for different types of masks (oronasal, nasal and pillow) and assess the impact on PAP titration. Methods: We retrospectively analyzed all CPAP titration polysomnography for one year. Anthropometric data and baseline apnea severity were documented. Results: A total of 497 patients were evaluated. Nasal masks were used in 82.3% (n = 409), pillow in 14.1% (n = 70) and oronasal in 3.6% (n = 18). There was no difference according to body mass index and baseline apnea-hypopnea index among the groups. The oronasal group was older and had higher titrated CPAP pressure, higher residual apnea-hypopnea index, lower sleep efficiency, more superficial N1 sleep and longer wake time after sleep onset. All other polysomnography outcomes were similar among the groups. The mean CPAP level was 11.6 ± 2.1 cm H2O for the oronasal mask, 10.1 ± 2.1 cm H2O for the nasal mask and 9.8 ± 2.2 cm H2O for the pillow. The residual apnea-hypopnea index was 10.4 ± 7.9 for the oronasal mask, 5.49 ± 5.34 events/h for the nasal mask and 4.98 ± 5.48 events/h for the pillow. The baseline apnea-hypopnea index was correlated with of a higher CPAP pressure for all the groups (p< 0.001 for the nasal group, p = 0.001 for the pillow group and p = 0.049 for the oronasal group). Body mass index and residual AHI were correlated with of a higher CPAP pressure for the nasal and pillow groups only (p < 0.001). Conclusion: The interface can have a significant impact on the effectiveness of PAP titration. Patients with oronasal masks have higher CPAP pressure, higher residual apnea-hypopnea index, lower sleep efficiency and higher wake time after sleep onset. Oronasal masks should not be recommended as the first choice for apnea patients. Level of evidence: Level 3.

O modelo proposto serve para triar os pacientes com alto risco para síndrome da apnéia e hipopnéia obstrutiva do sono. OBJETIVO: Avaliar a aplicabilidade clínica do modelo morfométrico de Kushida em uma amostra de pacientes com distúrbios respiratórios do sono e definir um valor de corte para discriminar os pacientes com apnéia leve, moderada e grave. FORMA DE ESTUDO: Coorte contemporânea longitudinal. MÉTODO: Foram estudados 80 pacientes com distúrbios respiratórios obstrutivos do sono, com idade entre 18 e 75 anos, de ambos os sexos e realizaram polissonografia prévia. O valor de corte do modelo morfométrico para distinguir os pacientes sem e com apnéia é de 70. RESULTADO: Na amostra estudada, os valores do modelo nos quatro grupos foram menores que 70. Não foi possível estabelecer um valor de corte de acordo com a gravidade da doença, devido à proximidade e ao aumento não-linear dos valores entre os pacientes não-apnéicos, com apnéia leve e moderada. CONCLUSÃO: O modelo morfométrico de Kushida é aplicável na prática clínica para a amostra selecionada e não foi possível estabelecer um valor de corte para separar os pacientes com síndrome da apnéia e hipopnéia do sono conforme sua gravidade.

The morphometric model is a useful screening test to investigate the possibility of OSAS in patients during initial office visits. AIM: To evaluate the clinical applicability of the Kushida morphometric model in a sample of patients with sleep-disordered breathing, and to define a cutoff value to differentiate patients with mild, moderate and severe apnea. METHOD: A sample of 80 patients with sleep respisratory disorder was studied. Patients were aged between 18 and 75 years, of both genders and had been submitted previously to polysomnography. The model cutoff value to distinguish between patients with or without apnea is 70. RESULTS: In this sample, the model cutoff value in all four groups was less than 70. It was impossible to establish a cutoff value according to the gravity of the condition, due to the proximity and the nonlinear increase in the values presented by the nonapneic group and those with mild and moderate apnea. CONCLUSION: The Kushida morphometric model can be applied in clinical practice to a selected sample and it was impossible to establish a cutoff value to separate patients with obstructive sleep apnea-hypopnea syndrome according to severity.