CMH Uses New Technology To Help Prevent Awareness Under Anesthesia

By: Wayne Bartlett, CRNA, MSN, Director of Anesthesia at Caldwell Memorial Hospital

The Caldwell Memorial Hospital Anesthesia Department has recently incorporated new technology to further assist in the care of general anesthesia patients. This new technology consists of monitors that measure brain activity during general anesthesia and are used to assist in preventing patients from having any recall or awareness during surgery. This technology has been in development for a decade and now is in use in major hospitals and teaching centers in the United States and worldwide as it is at CMH.

It is estimated that more than 20 million operations under general anesthesia are performed in the U.S. each year. One of the greatest priorities during general anesthesia is that the patient is comfortable and emerges from anesthesia without recall or memories of their experience. Prevention of this rare occurrence is a part of our Anesthesia Department's ongoing program to deliver modern, efficient, and safe anesthesia to surgical patients.

In the last decade there has been a larger amount of media coverage concerning awareness under anesthesia.  Books, talk shows, and news programs have reported stories of how some patients rarely are aware or awake during surgery. There is also a fictional movie portraying such an event that may be released this year. Today anesthesia providers are increasingly aware of recognition and prevention of such occurrence. This article provides information about Caldwell Memorial Hospital's new technology that can prevent patient awareness.

Patient awareness under general anesthesia is a rare condition that occurs when surgical patients can recall their surroundings or an event like pain related to their surgery while they were under general anesthesia. Patients undergoing other types of anesthesia such as moderate sedation or regional anesthesia (See side column.) may often have recall because they are not always completely “asleep” during the procedures. It is acceptable for patients to remember going into the operating room and waking up after the procedure. The rate of recall is reported to be as rare as 1 in 1,000 under general anesthesia. 

Awareness under anesthesia is not a new concern to anesthesia providers. It is well known that patients can have recall or feel pain in surgery if the anesthesia isn't sufficient. This usually occurs during a surgery for severe trauma or in very critically ill patients that can't undergo deep anesthesia without risking death. Today modern anesthesia providers can choose which anesthetic technique best fits a specific patient and his or her immediate needs. To assist the anesthesia provider some hospitals including Caldwell Memorial have began to use new technology called The Bis Monitor.

These monitors are named Bis (pronounced Biz) and consist of an adhesive strip that is attached to the patient's forehead.  (See illustration.) The strip is then attached to the monitor that sends information to the anesthesia provider. The Bis monitor is a form of an electroencephalogram (EEG), and measures brain waves representing electrical activity. During general anesthesia this information is measured and presented in a usable number form. The anesthesia provider can use this information along with the patient's vital signs to assess how "deep" a patient is during surgery. This information along with other clinical assessments helps assure that patients are fully asleep and will not remember anything while under anesthesia for a surgical procedure.

When a patient undergoes anesthesia for surgery, they receive complete one-on-one care. It is the sole duty of their anesthesia provider - a Certified Registered Nurse Anesthetist (CRNA) or an Anesthesiologist - to care for the patient before, during, and after the surgical procedure. The anesthesia provider monitors not only the vital signs such as blood pressure, pulse, and oxygen saturations but also the patient's overall condition. This is achieved with the help of monitors, direct visualization and personal assessment. The Bis monitor is another tool that can be used to gather valuable information about the patient during surgery.

The American Association of Nurse Anesthetists (AANA) and the American Society of Anesthesiologists (ASA) both agree that highly trained professionals such as CRNAs and anesthesiologists are the best monitors for patient care. For more information regarding patient awareness, visit Education/Awarenessbrochure.pdf.

At Caldwell Memorial Hospital, our highly trained and caring anesthesia providers and state-of-the-art medical monitors work together to keep your anesthesia experience safe and without side effects.

General Anesthesia - This type of anesthesia is a condition where the patient is fully unconscious. The patient may breathe on his or her own or require assistance to breathe. This may include the use of a mask or tracheal breathing tube.   The whole body is anesthetized and the patient is asleep. Medications used maybe given intravenously or by inhalation (via the lungs) or a combination of both. General anesthesia is commonly used for adults or children and for most procedures. Patients should not be aware of their surroundings during this type of anesthesia.

  1. Regional Anesthesia - This type of anesthesia is utilized by blocking sensations of feeling from certain areas of the body. Arms, legs, hands, or fingers can be "numb" by a local anesthetic injection. The anesthesia provider may provide additional sedation but the patient may still remember parts of the experience or be fully awake if desired. Examples are known as blocks, spinals, or epidurals.

  1. Monitored Anesthesia Care - This anesthesia often known as MAC is used frequently for minor or less painful procedures. Intravenous sedatives and a narcotic are given to provide comfort during the procedures. Patients may be asleep but not unconscious as in general anesthesia. Simple surgical procedures and procedures such as colonoscopies may utilize this type of anesthesia.