Using tracheal breathing sounds and anthropometric information for screening obstructive sleep apnoea during wakefulness.

Obstructive sleep apnoea (OSA) is a common yet underdiagnosed disorder. Undiagnosed OSA significantly increases perioperative morbidity and mortality for OSA patients undergoing surgery, requiring full anaesthesia. Tracheal breathing sounds characteristics during wakefulness have shown a high correlation with the apnoea-hypopnea index (AHI), while they are also affected by the anthropometric parameters, e.g., sex, age, etc. This study investigates the effects of the anthropometric parameters on our new quick objective OSA screening tool during wakefulness. Breathing sounds of 122 individuals (71 with AHI <15 as non-OSA and 51 with AHI > 15 as OSA) were recorded during wakefulness in the supine position. The spectra and bi-spectra of 81 (47 non-OSA) individuals' signals, which were randomly selected, were analysed as a training dataset to extract the most significant features with the lowest sensitivity to the anthropometric parameters. Using a support vector machine (SVM) classifier, these features resulted in 72.1, 64.7 and 77.5% testing classification accuracy, sensitivity and specificity, respectively. We also investigated classifying subjects into subgroups related to each anthropometric parameter and incorporating a voting procedure. This routine resulted in 83.6, 74.5 and 90.1% testing classification accuracy, sensitivity and specificity, respectively. In conclusion, it is possible to positively utilise the anthropometric information to enhance the classification accuracy for a reliable OSA screening procedure during wakefulness.

Enhancements to the multiple sleep latency test.

INTRODUCTION: The utility of multiple sleep latency tests (MSLTs) is limited to determining sleep onset latency (SOL) and rapid eye movement sleep latency. The odds ratio product (ORP) is a continuous index of sleep depth with values of 0, 1.0, and 2.5 reflecting very deep sleep, light sleep, and full wakefulness, respectively. We determined the time course of sleep depth during MSLT naps expecting that this would enhance the test's clinical utility. METHODS: Thirty MSLTs (150 naps) were performed for excessive somnolence. Patients indicated whether they slept (yes/no) after each nap. SOL was scored by two experienced technologists. Time course of ORP was determined with a commercial system. We determined ORP at SOL (ORPSOL), times ORP decreased <2.0, <1.5, <1.0 and <0.5 during the entire nap duration, and the integral of decrease in ORP over nap duration (ΔORPINT). RESULTS: SOL occurred almost invariably when ORP was between 1.0 and 2.0. Of 47 naps (21 patients) with SOL <5 minutes, ORP decreased <1.0 (light sleep) in <5 minutes in only 13 naps (nine patients) and <0.5 (deep sleep) in only two naps in one patient. The relation between ORPINT and frequency of sleep perception was well defined, allowing determination of a threshold for sleep perception. This threshold ranged widely (5-50 ΔORP*epoch). CONCLUSION: As currently identified, SOL reflects transition into a highly unstable state between wakefulness and sleep. Reporting the times of attaining different sleep depths may help better identify patients at high risk of vigilance loss. Furthermore, an ORPSOL outside the range 1.0-2.0 can help identify scoring errors.

Respiración y sueño: caso clínico de interés: niño de tres años de edad con síndrome de apnea obstructiva del seño grave e hipertensión pulmonar corregida con adenoamigdalectomía / Breathing and sleep. An interesting clinical case: three year old boy with severe obstructive sleep apnea and pulmonary hypertension reversed by adeno-tonsillectomy

Se presenta el caso de un niño de tres años y 11 meses de edad con hipertrofia de adenoides y amígdalas e historia de ronquido habitual, apneas observadas por los padres y sueño inquieto. En la polisomnografía se encontró que cursaba con síndrome de apnea obstructiva del sueño grave, debido a que presentaba un índice de apnea + hipopnea de 63.9 eventos por hora de sueño. Además, cursaba con hipoxemia e hipoventilación alveolar graves con valores promedio de SaO2 de 70.8 por ciento y PCO2et de 53 mmHg. También se demostró que tenía hipertensión pulmonar ligera y datos de cor pulmonale. El tratamiento con adenoamigdalectomía normalizó la respiración nocturna. Se hace una descripción clínica del caso, de la polisomnografía y una revisión del tema.

Riesgo quirúrgico en la apnea del sueño: implicaciones para las amigdalectomías / Surgical risk in sleep apnea: implications for tonsillectommies

El crecimiento amigdalino o adenoideo es una de las causas más frecuentes del síndrome de apnea obstructiva del sueño (SAOS), sobre todo en niños. La adenoamigdalectomía frecuentemente es curativa en estos pacientes, pero por otro lado tiene más riesgo que en niños sin el SAOS. Los pacientes con SAOS programados para adenoamigdalectomía requieren una valoración preoperatoria detallada que puede incluir una polisomnografía. Además son pacientes en quienes se necesita una vigilancia permanente desde el preoperatorio hasta el postoperatorio, los más graves en terapia intensiva. Es importante identificar entre los pacientes programados para adenoamigdalectomía a los que tienen signos y síntomas compatibles con el SAOS ya que conviene enviarlos a centros de referencia para su atención adecuada