A guest column by the American Society of Anesthesiologists, exclusive to KevinMD.com.

During the Civil War, anesthesia was provided by dipping cloth in chloroform or ether and holding it over a patient’s nose and mouth. Today, anesthetic medications are delivered in a controlled (and more civil) manner through specialized devices to provide unconsciousness for surgery.

Over the last several years, there has been significant media coverage of “waking up” during surgery. Also known as intraoperative awareness, this implies that during a period of intended general anesthesia, the brain is aroused by stimuli stored in memory. Every week I have at least one patient express concern about waking up during surgery. Fortunately, intraoperative awareness is extremely rare and, according to a new study by the Royal College of Anaesthesists and the Association of Great Britain, only one in 15,000 patients experience this phenomenon.

Media coverage of this issue has resulted in the medical community proactively addressing and researching methods to prevent, identify and treat intraoperative awareness. In fact, mindfulness about intraoperative awareness is a good thing, especially when it is discussed factually and is not sensationalized. Here are some facts every patient undergoing general anesthesia should know:

• While you are asleep, your anesthesiologist uses sophisticated technology to deliver specific dosages of anesthetic medications. They also carefully and vigilantly monitor your heart rate, blood pressure and breathing pattern to help gauge the depth of anesthesia.

• It is possible to remember events or conversations in the operating room before going to sleep or after waking from your surgery. However, this does not constitute awareness under anesthesia. Additionally, some procedures are performed with sedation (e.g. colonoscopies, cataracts, biopsies) instead of general anesthesia.

• “Not giving enough” anesthesia is not the only cause of intraoperative awareness. More commonly, awareness occurs in patients who have impaired heart function, lost a significant amount of blood, or are undergoing emergency surgeries or Cesarean sections. Alternatively, patients with chronic pain conditions, alcohol abuse or obesity may have higher drug requirements.

• Not all awareness is the same. It can vary from specific and vivid to dream-like memories of your surgery. Most patients who have experienced awareness did not feel pain, although some described experiencing pressure.

As a patient, there are a number of things you can do that may decrease your risk of intraoperative awareness:

• During your preoperative interview, it is important to provide an accurate list of medications, particularly pain, anxiety and sleep medications.

• Be forthright about how much alcohol you drink and the approximate the number of cans, glasses or ounces you consume in a day or week, or if you use any illegal drugs.

• Ask your anesthesiologist if you have a unique or increased risk for anesthesia awareness.

Doctors and researchers have shown there is a decreased occurrence of anxiety and patients are less likely to avoid future medical care when intraoperative awareness is identified early and appropriately managed. If you feel you may have experienced awareness under anesthesia, alert your anesthesiologist.

Nina Singh-Radcliff is a member of the American Society of Anesthesiologists’ Committee on Communications.