Marcelo Palmeira Rodrigues

Backgrounds: In patients with acromegaly, sleep apnea-related hypoxemia results in considerable morbidity and mortality. Aims: To evaluate the relative weight of pathogenic factors in predicting such hypoxemia. Methods: In this cross-sectional study, 34 acromegaly patients were submitted to clinical evaluation, nocturnal oximetry, and nasolaryngeal airway tomography. GH, IGF-I, and its upper limit normal value were measured. Nocturnal hypoxemia was defined as >5 episodes of desaturation/h of sleep. Craniofacial abnormalities were expressed using a linear parameter index (LPI). Nocturnal hypoxemia was predicted using logistic regression, including the variables markers of craniofacial abnormality, hormonal alteration, and obesity. Coefficients were standardized in order to determine their effect magnitudes relative to the outcome. The best model included the variables gender, age, LPI, body mass index (BMI), and IGFI upper limit normal value. Main results: In the absence of the age and gender variables, the odds ratio for the LPI (1.60) was slightly higher than those found for BMI (1.49) and upper limit normal value (1.40). When the data were adjusted for age, the hormone upper limit normal value presented little alteration (1.49), although the decrease in the LPI was considerable (1.21), as was the increase in the BMI (2.18). The relative weight of the LPI was age-dependent. The gender variable did not alter the relevance of the others. Conclusions: The effects that craniofacial aspect, obesity, and hormonal alterations have on nocturnal hypoxemia are of similar magnitude.

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. With the objective of identifying hypoxemia based on clinical data, we conducted a cross-sectional study of 34 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. 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%. 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.

To evaluate the peak inspiratory pressure and ventilation rate achieved by physicians when using a neonatal self-inflating bag on a lung model.

OBJECTIVE: To evaluate the peak inspiratory pressure, tidal volume and respiratory rate achieved during manual ventilation of premature lambs, using a self-inflating bag. METHODS: In this descriptive, experimental study, five pairs of physicians, selected at random among 35 neonatologists working at a neonatal intensive care unit and with experience in the resuscitation of newborn infants, ventilated five intubated premature lambs using a self-inflating bag. Pressure and flow monitor signals were passed through a transducer and digitized for recording and analysis. Tidal volume and pressure curves were obtained from the integral of flow rate, at peak, during the last 50 seconds of every fifth minute, and analyzed. RESULTS: Median pressure was 39.8 (IQ25-75% 30.2-47.2) cmH2O; being below 20 in 1.1% of cases and above 40 in 49.1%. Seven out of 10 physicians produced more than six pressure peaks of over 40 cmH2O. Median tidal volume/kg was 17.8 (IQ25-75% 14.1-22.4) mL, being below 5 mL in 0.1% of cases and greater than or equal to 20 mL in 37.7%. All of the physicians propelled five or more ventilation cycles with tidal volume/kg of 20 mL or more. Respiratory rate was between 30 and 60 cycles/minute in 65.9% of cases, being below 30 in 6.8% of cases and over 60 in 27.3% of cases. CONCLUSIONS: There was major variation in peak inspiratory pressure and tidal volume/kg values, which were in many cases elevated, attaining levels that habitually cause biotrauma, while respiratory rates were adequate in the majority of cases.OBJETIVO: Avaliar o pico de pressão inspiratória, o volume corrente e a freqüência respiratória obtidos durante ventilação manual de carneiros prematuros, utilizando balão auto-inflável. MÉTODOS: Estudo experimental descritivo em que cinco duplas de médicos selecionados aleatoriamente entre 35 neonatologistas que trabalham em unidade de terapia intensiva neonatal e experientes em reanimação de recém-nascidos ventilaram cinco carneiros prematuros intubados, utilizando balão auto-inflável. Os sinais de pressão e fluxo eram captados, convertidos por meio de transdutores e digitalizados para armazenamento e análise. Foram avaliadas curvas de pressão e de volume corrente, este a partir da integral do fluxo, em suas medidas de pico, nos 50 segundos finais de cada 5 minutos. RESULTADOS: A mediana da pressão foi de 39,8 (IQ25-75% 30,2-47,2) cmH2O; foi menor que 20 em 1,1% das vezes e maior que 40 em 49,1%. Sete em 10 médicos propiciaram mais de seis picos de pressão maiores que 40 cmH2O. A mediana do volume corrente/kg foi de 17,8 (IQ25-75% 14,1-22,4) mL, sendo menor que 5 mL em 0,1% das vezes e igual ou maior que 20 mL em 37,7%. Todos os médicos impuseram cinco ou mais ciclos ventilatórios com volume corrente/kg de 20 mL ou mais. A freqüência situou-se entre 30 e 60 ciclos/minuto em 65,9% das vezes, sendo menor que 30 em 6,8% e maior que 60 em 27,3% das vezes. CONCLUSÃO: Ocorreu grande variabilidade nos valores do pico de pressão inspiratória e do volume corrente/kg, sendo muitas vezes elevados e alcançando níveis indutores de biotrauma; para a freqüência respiratória, os valores foram adequados na maioria das vezes.Universidade de BrasíliaUnBUniversidade Federal de São Paulo (UNIFESP)UnB Hospital Universitário da UnBUniversidade de São Paulo Faculdade de Medicina Instituto da Criança do Hospital das ClínicasUNIFESPSciEL