A 60 year old female patient underwent modified radical mastectomy under general anesthesia. She is very anxious preoperatively. What monitor anesthetist might have used during surgery so that she does not remember anything intraoperative event.
**Core Concept**
The anesthetist may use a monitor that prevents the patient from remembering intraoperative events, which is a technique used to reduce stress and anxiety associated with surgery. This is particularly important for patients with high anxiety levels, such as the 60-year-old female patient in this scenario.
**Why the Correct Answer is Right**
The anesthetist might have used a bispectral index (BIS) monitor, which measures the level of consciousness by analyzing the patient's electroencephalogram (EEG) activity. BIS values range from 0 to 100, with 0 indicating no brain activity and 100 indicating full consciousness. A BIS value of 40-60 is typically considered optimal for general anesthesia, as it allows for sufficient depth of anesthesia to prevent recall of intraoperative events while minimizing the risk of respiratory depression.
**Why Each Wrong Option is Incorrect**
* **Option A:** Propofol is a commonly used anesthetic agent, but it is not a type of monitor used to prevent recall of intraoperative events.
* **Option B:** Intraoperative transesophageal echocardiography (TEE) is used to monitor cardiac function during surgery, but it does not prevent recall of intraoperative events.
* **Option D:** Intraoperative nerve stimulation (IONM) is used to monitor the integrity of nerve function during surgery, but it does not prevent recall of intraoperative events.
**Clinical Pearl / High-Yield Fact**
BIS monitoring is a useful tool for optimizing anesthesia depth and preventing recall of intraoperative events, but it is not a substitute for proper anesthesia technique and patient monitoring.
**Correct Answer:** C.