Hyperventilation Case Study
2. At a party, Dickson was challenging his friends to see who could hold their breath and dive longest in the pool. Hoping to extend his time underwater, Dickson hyperventilates for several minutes before diving into the pool. Shortly after entering the water, he lost consciousness and nearly drowned. Explain what might have caused this.
Hyperventilation is defined as breathing in excess of the metabolic needs of the body, eliminating more carbon dioxide that is produced, and consequently, resulting in respiratory alkalosis and elevated blood pH (Folgering, 1999). It is believed that hyperventilation before breath hold swimming and diving makes it possible for a person to extend the time under water (Craig, 1976). Therefore, Dickson hyperventilated …show more content…
However, he has over-hyperventilated and this result in him losing consciousness. Under normal respiratory conditions, arterial PCO2 level of the blood is maintained between 35 to 45mmHg. The central chemoreceptors located in the medulla of the brain is responsible for detecting changes in carbon dioxide levels. As the blood brain barrier is readily permeable to carbon dioxide, any increase in arterial CO2 corresponds to a similar rise in brain extracellular fluid (ECF) PCO2. When there is increased PCO2 in the ECF, carbonic anhydrase is responsible for producing a corresponding increase in H+ ions through the following chemical equation: CO2 + H2O ⇄ H+ + HCO3-
Therefore, the increase in PCO2 will lower the pH due to increase in hydrogen ions, activating the central chemoreceptors to stimulate the Dorsal (DRG) and Ventral Respiratory group (VRG) which reflexly increase ventilation. Furthermore, the peripheral chemoreceptors located on the carotid arteries and aortic bodies is also responsible for detecting changes in arterial PCO2. Therefore, the human body tend to favour the hypercapnic drive, where response for increased ventilation occurs to exhale excess carbon dioxide into the atmosphere as arterial and brain PCO2 levels exceeds the response level of
Hyperventilation is defined as breathing in excess of the metabolic needs of the body, eliminating more carbon dioxide that is produced, and consequently, resulting in respiratory alkalosis and elevated blood pH (Folgering, 1999). It is believed that hyperventilation before breath hold swimming and diving makes it possible for a person to extend the time under water (Craig, 1976). Therefore, Dickson hyperventilated …show more content…
However, he has over-hyperventilated and this result in him losing consciousness. Under normal respiratory conditions, arterial PCO2 level of the blood is maintained between 35 to 45mmHg. The central chemoreceptors located in the medulla of the brain is responsible for detecting changes in carbon dioxide levels. As the blood brain barrier is readily permeable to carbon dioxide, any increase in arterial CO2 corresponds to a similar rise in brain extracellular fluid (ECF) PCO2. When there is increased PCO2 in the ECF, carbonic anhydrase is responsible for producing a corresponding increase in H+ ions through the following chemical equation: CO2 + H2O ⇄ H+ + HCO3-
Therefore, the increase in PCO2 will lower the pH due to increase in hydrogen ions, activating the central chemoreceptors to stimulate the Dorsal (DRG) and Ventral Respiratory group (VRG) which reflexly increase ventilation. Furthermore, the peripheral chemoreceptors located on the carotid arteries and aortic bodies is also responsible for detecting changes in arterial PCO2. Therefore, the human body tend to favour the hypercapnic drive, where response for increased ventilation occurs to exhale excess carbon dioxide into the atmosphere as arterial and brain PCO2 levels exceeds the response level of