Abdominal muscle activity in obstructive sleep apnoeas.
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Abdominal Muscles↗
Biomedical subjects
S Sanci
Publications and source records attributed to S Sanci.
Expiratory timing in obstructive sleep apnoeas.
Diaphragmatic electromyogram was recorded during NREM sleep in 4 patients affected by obstructive sleep apnoea (OSA) syndrome in order to evaluate the behaviour of expiratory time (TE) in the course of the obstructive apnoea-ventilation cycle. The two components of TE, i.e. time of post-inspiratory inspiratory activity (TPIIA) and time of expiratory phase 2 (TE2) were separately analysed. TPIIA showed a short duration, with only minor variations, within the apnoea, while its duration was more variable and longer in the interapnoeic periods: the longest TPIIA values were associated with the highest inspiratory volumes in the same breaths. This behaviour seemed regulated according to the need of a more or less effective expiratory flow braking, probably as a result of pulmonary stretch receptors discharge. Conversely TE2 showed a continuous gradual modulation, progressively increasing in the pre-apnoeic period, decreasing during the apnoea and increasing in the post-apnoeic period: these TE2 variations seemed related to oscillations in chemical drive. These data show that TE in the obstructive apnoea-ventilation cycle results from a different modulation in its two components and suggest that both mechanical and chemical influences play a role in its overall duration.
Adult↗
Obesity as a possible cause of respiratory failure in bilateral diaphragmatic paralysis. Case report.
An obese woman with respiratory failure and bilateral diaphragmatic paralysis, was studied in order to investigate the effects of weight loss on respiratory function during wakefulness and sleep. The patient was studied on 5 different occasions during which diurnal blood gas analysis, spirometry, CO2 rebreathing test, nitrogen wash-out test and a nocturnal polysomnographic study were performed. The follow-up period lasted 9 months, during which the patient progressively lost 19 kg. Progressive improvement in awake blood gas tensions (PaO2 + 21 mmHg, PaCO2 - 16 mmHg) as well as in nocturnal oxyhemoglobin saturation and transcutaneous PCO2 were observed; at the same time only minor changes in responsiveness to CO2 and in lung volumes were found. Conversely alveolar efficiency for CO2, obtained with the nitrogen wash-out test, in the supine posture increased from 81.7 to 90.5%, indicating an improvement in ventilation/perfusion ratio as a possible determinant of blood gas tension improvement during wakefulness and, as a consequence, also during sleep. We conclude that obesity is one possible cause of the occurrence of respiratory failure in bilateral diaphragmatic paralysis.
Adult↗