that's what i m trying to say, although perfusion defect, but still due to hyperventilation, it's alkalosis. . .PO2 will be low . .Hyperventilation is the mechanism in ALL cases
Hyperventilation (ie increased alveolar ventilation) is the mechanism responsible for the lowered arterial pCO2 in ALL cases of respiratory alkalosis.
This low arterial pCO2 will be sensed by the central and peripheral chemoreceptors and the hyperventilation will be inhibited unless the patient's ventilation is controlled.
Causes of Respiratory Alkalosis
1. Central Causes (direct action via respiratory centre)
Anxiety-hyperventilation syndrome (psychogenic)
Other 'supra-tentorial' causes (pain, fear, stress, voluntary)
Various drugs (eg analeptics, propanidid, salicylate intoxication)
Various endogenous compounds (eg progesterone during pregnancy, cytokines during sepsis, toxins in patients with chronic liver disease)
2. Hypoxaemia (act via peripheral chemoreceptors)
Respiratory stimulation via peripheral chemoreceptors
3. Pulmonary Causes (act via intrapulmonary receptors)
Pulmonary oedema (all types)
4. Iatrogenic (act directly on ventilation)
Excessive controlled ventilation
yes u rright !!! uggh i mixed that up.. its deadspace cuz ventilation going on without perfusion like happens in apex of lungs!!WOULDN'T T ACT LIKE A DEAD SPACE?
SHUNT IS INCASE OF AIRWAY OBSTRUCTION..:redcheeks;
I should just remember:Always remeber..
watever causes Dyspnea, Hyperventilation.. RESP ALKALOSIS.. u r losing CO2
includes Anxiety, PE, Panick Attacks, Pregnancy ( stimulation of central resp drive)
n remebr Hyperventilation can decrease Intracranial Pressure, by decreasing CO2 ,cerebral blood flow decreases... so ppl Hyperventilate in setting of Cerebral Edema!
n to contrast ,watever suppresses ur resp system.. like OPIODS, or THORACIc Muscle problems, u kno paralysis n stuff, COPD .. causes RESP ACIDOSIS and cuz u r retaining CO2