What is the Apnoeic threshold?

The concept of apneic threshold implies that there is a threshold for arterial CO 2 tension below which spontaneous breathing ceases. This paper describes a new method for measuring this threshold under clinical conditions in the operating room.

How does CHF cause central sleep apnea?

CHF affects control of breathing by increasing chemosensitivity and the circulatory delay, and thereby predisposes to central sleep apnea (CSA), most classically in a crescendo-decrescendo pattern of respiration known as Cheyne-Stokes respiration (CSR).

Is sleep apnea a breathing problem?

Sleep apnea is a potentially serious sleep disorder in which breathing repeatedly stops and starts. If you snore loudly and feel tired even after a full night’s sleep, you might have sleep apnea. The main types of sleep apnea are: Obstructive sleep apnea, the more common form that occurs when throat muscles relax.

How long can you be apneic?

Apnea (AP-nee-ah) is a pause in breathing that lasts 20 seconds or longer for full-term infants.

What is the MAC of co2?

200 mm Hg
1.0 MAC of CO2 is 200 mm Hg.

Can a CPAP machine help congestive heart failure?

People with sleep apnea, especially those over 60, could decrease their risk of heart failure by using CPAP masks at night to help with breathing, according to new research.

Can CPAP improve ejection fraction?

CPAP-treated patients showed a 9% improvement in left-ventricular ejection fraction and reduced daytime systolic blood pressure and heart rate compared with control patients who demonstrated no changes.

What is apnea threshold and hypopnea?

The apnea threshold was determined as the mean P etCO2 of the lowest three consecutive breaths preceding the first apnea (indicated by the thick horizontal line ). . Hypopnea was defined as two or more untriggered efforts detected on the mask pressure tracing associated with a 50% or greater reduction in tidal volume.

Does hypocapnic hypoxemia decrease proximal tubular reabsorption?

Using the renal clearance of lithium as an index of proximal tubular outflow, this study tested the hypothesis that acute hypocapnic hypoxemia decreases proximal tubular reabsorption to the same extent as hypocapnic normoxemia (hyperventilation) and that this response is blunted during normocapnic hypoxemia.

What is a good apnea/hypopnea index?

The CSA group had an apnea/hypopnea index (AHI) of 10 or more per hour of sleep with at least 80% of the respiratory events central in nature. The control group had an AHI of 5 or less per hour of sleep. The patients in the two groups were matched with respect to age, sex, body mass index (BMI), and left ventricular ejection fraction (LVEF).

How is the natriuretic-diuretic response abolished in patients with hypocapnia?

The natriuretic-diuretic response can be abolished if normocapnic conditions are maintained. [20,23] These effects of hypocapnia and alkalosis may be attributed to a decrease in peripheral chemoreceptor sensitivity to hypoxemia, [1,2] to the inhibition of renal proximal tubular reabsorption of bicarbonate and sodium, [25,26] or to both.