We have briefly mentioned two physicochemical properties of the volatile agents relating to their solubility. One was the oil:gas partition coefficient, which determines potency of an inhaled anaesthetic agent.

Question: Can you recall the other and its effect on speed of onset of anaesthesia?

Answer

We have briefly mentioned two physicochemical properties of the volatile agents relating to their solubility. One was the oil:gas partition coefficient, which determines potency of an inhaled anaesthetic agent.

Question: Can you recall the other and its effect on speed of onset of anaesthesia?

Answer: The blood:gas partition coefficient. Volatile agents with a low blood gas partition coefficient have a rapid speed of onset of anaesthesia.

Question: If the patient breathes more quickly and increases their minute ventilation, how might this affect speed of onset of anaesthesia?

Answer

We have briefly mentioned two physicochemical properties of the volatile agents relating to their solubility. One was the oil:gas partition coefficient, which determines potency of an inhaled anaesthetic agent.

Question: Can you recall the other and its effect on speed of onset of anaesthesia?

Answer: The blood:gas partition coefficient. Volatile agents with a low blood gas partition coefficient have a rapid speed of onset of anaesthesia.

Question: If the patient breathes more quickly and increases their minute ventilation, how might this affect speed of onset of anaesthesia?

Answer

We have briefly mentioned two physicochemical properties of the volatile agents relating to their solubility. One was the oil:gas partition coefficient, which determines potency of an inhaled anaesthetic agent.

Question: Can you recall the other and its effect on speed of onset of anaesthesia?

Answer: The blood:gas partition coefficient. Volatile agents with a low blood gas partition coefficient have a rapid speed of onset of anaesthesia.

Question: If the patient breathes more quickly and increases their minute ventilation, how might this affect speed of onset of anaesthesia?

Answer: More volatile agent reaches the alveoli, so speed of onset of anaesthesia is quicker.

Question: If the patient's cardiac output increases, what effect might this have on speed of onset of anaesthesia?

Answer

We have briefly mentioned two physicochemical properties of the volatile agents relating to their solubility. One was the oil:gas partition coefficient, which determines potency of an inhaled anaesthetic agent.

Question: Can you recall the other and its effect on speed of onset of anaesthesia?

Answer: The blood:gas partition coefficient. Volatile agents with a low blood gas partition coefficient have a rapid speed of onset of anaesthesia.

Question: If the patient breathes more quickly and increases their minute ventilation, how might this affect speed of onset of anaesthesia?

Answer: More volatile agent reaches the alveoli, so speed of onset of anaesthesia is quicker.

Question: If the patient's cardiac output increases, what effect might this have on speed of onset of anaesthesia?

Answer: You need to think about this carefully. If cardiac output increases then blood passes more quickly through the lungs and less anaesthetic is taken up in the same time. As a result speed of onset of anaesthesia is slower. The converse is true if the cardiac output falls.