Alterações da estrutura e função respiratórias durante a vigília e o sono na acromegalia

Marcelo Palmeira Rodrigues

Purposes: Patients with acromegaly have increased mortality due to respiratory disease when compared to whole population. Hypoxemia secondary to sleep apnea is commonly seen in patients with acromegaly, and this alteration apparently leads to considerable morbidity and mortality among such patients. This research has the objective of identifying hypoxemia based on clinical data, of knowing pathogenic factors proportion in its establishment and to realize pulmonary structure, connecting it to respiratory function tests. Methods: We conducted a cross-sectional study of 36 patients with acromegaly, all of whom were submitted to nocturnal oximetry and evaluation of snoring, as well as to the determination of body mass index (BMI) and neck circumference. In addition, daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). In this study, sleep hypoxemia was defined as five or more episodes of desaturation per hour. They also were submitted to an upper airway and chest computerized tomography, spirometry, lung volumes measure, oximetry during exercise, diffusion capacity (DLCO) and maximal inspiratory and expiratory pressure. A control group of 24 patients were used to compare chest tomography. Serum levels of GH, IGF-I and ULNV were obtained from all patients. An index that measure craniofacial abnormalities (CAI) was created, as well as a logistic regression model with standardized coefficients to predict hypoxemia using variables which represent obesity, craniofacial abnormalities and hormone dysfunction. Results: The sensitivity and specificity of the various parameters in predicting such hypoxemia were, respectively, as follows: snoring (92.9% and 35%); BMI >28.5 kg/m2 (71.4% and 60%); neck circumference >44 cm (28.6% and 95%); ESS score >10 (42.9% and 70%). For patients with a neck circumference of more than 44 cm, the probability of sleep hypoxemia was found to increase from 41% (pre-test) to 80% (post-test). For patients with a neck circumference of less than 44 cm, positivity for two or three of the other parameters (snoring, ESS score >10 and BMI >28.5 kg/m2) increased the post-test probability to 62%, whereas positivity for only one (or none) reduced post-test probability to 8%. A logistic model was shown to be significant (p<0,01) and was created with age, sex, BMI, CAI and ULNV. In the absence of age and sex, the CAI odds ratio (1,60) was a bit higher than BMI (1,49) and ULNV (1,40). When the data were controlled by age, ULNV remained almost the same (1,49), but the CAI decreased (1,21) and the BMI increased (2,18). The CAI`s influence in sleeping hypoxemia was age dependent. Control by sex variable didnt change other variables significantly. There werent any change in the chest tomography, when compared to control group. Seven patients (21%) showed awakening hypoxemia, although six of whom had another respiratory disease. Eight (22%) showed obstructive dysfunction, but five of whom had another respiratory disease. Three (8%) showed low inspiratory and five (14%) low maximal expiratory pressure. No one had an abnormal DLCO. Conclusions: We can conclude that the clinical parameters evaluated allowed us to predict, with considerable accuracy, whether or not sleep hypoxemia would occur in patients with acromegaly. Craniofacial abnormalities, obesity and hormone dysfunction contribute in a similar way to produce sleep hypoxemia. The majority of respiratory function disorders founded in these patients were explained by another disease than acromegaly and there isnt any relationship with lung structure.

Alterações da estrutura e função respiratórias durante a vigília e o sono na acromegalia

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