Recent studies at the National Respiratory Center
in Colorado indicate that theophylline, like caffeine has both desirable and undesirable action in children.
All the changes are mediated by the high progesterone level influencing respiratory center
through lowering the threshold and increasing the sensitivity.
adaptation occurs in response to chronically high [CO.sub.2] levels.
There is possibility that all these chemical mediators stimulate or excite the vagal receptors or afferents to induce the inhibitory effect on the respiratory center
resulting in respiratory failure and death of the animal.
All tests were carried out at SHAR Hospital Respiratory Center
in Sulaimani city.
The breath holding time measures the level of the threshold of the respiratory center
to the partial pressure of the carbon dioxide level.
Once it falls to a certain level, the respiratory center
in the brain becomes stimulated and the person arouses briefly to take some quick, deep breaths to restore the blood oxygen level.
McBride, who is also director of the respiratory center
at Children's Hospital Medical Center of Akron (Ohio).
The new perspective theory concentrates on the direct stimulatory action of progesterone on respiratory center
, with t/2 of 30 min.
In normal breathing after a particular degree of stretching or even before this, stretch receptors (situated in the walls of the alveoli) are stimulated and send information to the respiratory center
so that exhalation sets in.
This occurs despite the lack of respiratory disease or other factors that could impair ventilation such as restricted chest wall movement, excessive airway secretions, lung tissue damage or destruction, or impaired function of the respiratory center
in the brain.5 Since the hypoventilation seems not to be related to any other factor except obesity, it is called obesity-related hypoventilation syndrome (OHS).
Premature infants may experience "apnea of prematurity" which is felt to be due to relative immaturity of the respiratory center
in the brain stem which causes the infant to respond inefficiently to rising levels of carbon dioxide.