Pre-oxygenation is done to?
**Core Concept**
Pre-oxygenation is a process used to increase the oxygen stores in the body before a procedure that may lead to apnea, such as endotracheal intubation or surgery. This is achieved by having the patient breathe 100% oxygen for a certain period, allowing the body to accumulate oxygen stores in the lungs, blood, and tissues.
**Why the Correct Answer is Right**
Pre-oxygenation allows the patient to utilize their functional residual capacity (FRC) of oxygen, which is the amount of oxygen remaining in the lungs after normal exhalation. The FRC is increased by pre-oxygenation, allowing the patient to tolerate apnea for a longer period before hypoxemia occurs. The body's oxygen stores, including the oxygen in the lungs, blood, and tissues, are replenished, delaying the onset of hypoxemia during apnea.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because pre-oxygenation is not primarily done to reduce the risk of aspiration. While it is true that pre-oxygenation can help to increase the pH of the stomach by reducing CO2 levels, this is not the primary reason for pre-oxygenation.
* **Option B:** This option is incorrect because pre-oxygenation is not solely done to increase the patient's comfort level. While pre-oxygenation can help to reduce anxiety and discomfort, this is not the primary reason for pre-oxygenation.
* **Option C:** This option is incorrect because pre-oxygenation is not primarily done to reduce the risk of cardiac arrhythmias. While pre-oxygenation can help to reduce the risk of cardiac arrhythmias by increasing the oxygen supply to the heart, this is not the primary reason for pre-oxygenation.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that pre-oxygenation should be continued for at least 3-5 minutes to achieve optimal results. This allows the body to accumulate sufficient oxygen stores to tolerate apnea for a longer period.
**Correct Answer:** C.