Which of the following occurs after hyperventilation with 6% CO2 in inspired air?
Hyperventilation with 6% CO2 is followed by continued hyperventilation till alveolar pCO2 drops towards normal. Ventilatory responses to CO2 There is a linear relationship between increase in % of CO2 in inspired air and respiratory minute volume. The upper limit for this linearity is 6% of alveaolar PCO2. When the CO2 content of the inspired gas is >7%, the alveolar and the aerial PCO2 begin to rise abruptly inspite of hyperventilation leading to hypercapnia. Hypercapnia depresses the central nervous system, including respiratory centers leading to CO2 narcosis (a headache, confusion and eventually coma) Mechanism: Increased CO2 in inspired air - Increased alveolar PCO2 - Increased aerial PCO2 - Stimulation of central chemoreceptors - Stimulation of ventilation - Alveolar PCO2 drops toward normal. Ref: Ganong&;s Review of Medical Physiology 26th edition Pgno: 645-657
Continued hyperventilation
Apnoea
Cheyne-stokes breathing
Kussumaul's breathing
Respiratory system