Cerebrovascular Responses During Voluntary Breath Holding are Larger than Rebreathing

Voluntary breath-holding in the morning and in the evening.

The aim of the present study was to determine whether or not voluntary breath-holding time (BHT) changes with the time of the day. BHT with airways closed at end-expiration was measured in six male subjects in the sitting position during the morning (08.00-12.00 hours, on days 1, 6, 7 and 8) and evening (20.00-24.00 hours, on days 2 and 4). BHT increased with the number of days of testing and, ...

Assessment of breath holding index during orthostasis.

The aim of the study was to assess differences in cerebrovascular reactivity in healthy subjects during orthostasis. Twenty healthy volunteers (11 men and 9 women) with no atherosclerotic risk factors were evaluated by use of transcranial Doppler. The breath holding index (BHI) was obtained in supine and upright posture using standardized procedure. Student's t-test was used on comparison of th...

Assessing and ensuring patient safety during breath-holding for radiotherapy

OBJECTIVE While there is recent interest in using repeated deep inspiratory breath-holds, or prolonged single breath-holds, to improve radiotherapy delivery, breath-holding has risks. There are no published guidelines for monitoring patient safety, and there is little clinical awareness of the pronounced blood pressure rise and the potential for gradual asphyxia that occur during breath-holding...

Cerebral blood flow-related signal changes during breath-holding.

BACKGROUND AND PURPOSE In the past, functional MR imaging techniques have been used successfully to determine cerebrovascular reactivity (CVR) to various stimuli, complementing the arsenal of functional brain investigations feasible with MR imaging. While previous studies have focused on blood oxygenation changes under vasodilatory stress, the aim of this study was to assess regional cerebral b...

The limits of breath holding.