American Association of Nurse Anesthetists Publishes Position Statement on Unintended Awareness under General Anesthesia.

NEWTON, Mass. -- Aspect Medical Systems (NASDAQ: ASPM) today announced that the American Association of Nurse Anesthetists (AANA) has published a position statement regarding unintended awareness under general anesthesia on the AANA Web site. Unintended awareness occurs when patients do not receive enough anesthesia to remain unconscious, leaving them at risk for becoming aware of what is happening and remembering this experience after the surgery is over. The position statement was written to guide AANA members (more than 35,000 Certified Registered Nurse Anesthetists and student nurse anesthetists) in minimizing the incidence of unintended awareness and to provide guidance for clinical policy development to address awareness.

"We are pleased that the AANA leadership has prepared this guidance for members," said Nassib Chamoun, president and CEO of Aspect. "This document provides further clinical support to guide anesthesia professionals in reducing the risk of awareness and underscores awareness as an important patient safety concern."

Position Statement Guidance to Clinicians

The position statement identifies the possible causes of awareness and acknowledges the adverse psychological consequences that patients may experience following awareness. The document also states that awareness occurs in one to two cases per thousand patients receiving general anesthesia. To address this clinical concern, the position statement recommends that every anesthetizing location develop a defined written policy that includes the following practices:

--Assessing patient risk for awareness prior to surgery and anesthesia

--Ensuring proper function of anesthesia equipment

--Developing an anesthesia care plan that includes appropriate pharmacologic agents, anesthesia techniques and patient monitoring techniques to reduce risk of awareness

--Considering brain function monitoring in situations where awareness risk is increased

--Conducting patient assessments post-surgery to identify and manage possible occurrences of awareness.

The position statement notes that use of brain function monitors along with other patient monitoring modalities has been shown to reduce patient risk of awareness. Further, the document states that not all brain monitors have been studied for their effectiveness in reducing the incidence of awareness and individual health care facilities and anesthesia departments should consider clinical evidence when selecting brain monitors for use to reduce risk of awareness.

"We support the position statement suggestion that clinical evidence be considered when evaluating brain function monitoring technologies," said Chamoun. "BIS is the only brain monitoring technology or clinical intervention that has been shown in large scale, prospective clinical research to reduce the incidence of awareness, and the only technology to receive clearance from the FDA to assist clinicians in reducing risk of awareness."

The position statement can be found on the AANA Web site at the following address: http://www.aana.com/Resources.aspx?ucNavMenu_TSMenuTargetID=51&uc NavMenu_TSMenuTargetType=4&ucNavMenu_TSMenuID=6&id=1747 (Due to the length of this URL, it may be necessary to copy and paste it into your Internet browser's URL address field. You may also need to remove an extra space in the URL if one exists.)

About BIS Monitoring

Using a sensor placed on the patient's forehead, BIS monitoring translates information from the electroencephalogram (EEG) into a single number that represents each patient's level of consciousness. This number - the BIS value - ranges from 100 (indicating an awake patient) to zero (indicating the absence of brain activity). Using the BIS value to guide administration of anesthetic medication, in conjunction with other vital signs, allows clinicians to make better-informed decisions to achieve optimal anesthesia.

About Aspect Medical Systems, Inc.

Aspect Medical Systems, Inc. (NASDAQ: ASPM) is a global market leader in brain monitoring technology. To date, the Company's Bispectral Index (BIS) technology has been used to assess more than 15.2 million patients and has been the subject of approximately 2,300 published articles and abstracts. BIS technology is installed in approximately 70 percent of hospitals listed in the July 2005 U.S. News and World Report ranking of America's Best Hospitals and in approximately 47 percent of all domestic operating rooms. In the last twelve months BIS technology was used in approximately 14 percent of all U.S. surgical procedures requiring general anesthesia or deep sedation. BIS technology is available in more than 160 countries. Aspect Medical Systems has OEM agreements with seven leading manufacturers of patient monitoring systems. The company is also investigating how other methods of analyzing brain waves may aid in the diagnosis and management of neurological diseases, including depression and Alzheimer's disease. For more information, visit Aspect's Web site at http://www.aspectmedical.com.

Safe Harbor Statement

Certain statements in this release are forward-looking and may involve risks and. There are a number of important factors that could cause actual results to differ materially from those indicated by these forward-looking statements. For example, the Company may not achieve widespread market acceptance of its BIS monitoring technology among anesthesiologist s and other anesthesia providers, including members of the AANA who review the position statement. The Company also faces other barriers to market penetration and acceptance. The Company may not be able to compete with new products or alternative techniques that may be developed by others, including third-party anesthesia monitoring products approved by the FDA, and also faces competitive and regulatory risks relating to its ability to successfully develop and introduce enhancements and new products. Cases of awareness with recall during monitoring with the BIS system and significant product liability claims are among the factors that could limit market acceptance. There are additional factors that could cause the Company's actual results to vary from its forward-looking statements, including without limitation those set forth under the heading "Risk Factors" in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2005, as filed with the Securities and Exchange Commission. In addition, any forward-looking statements represent the Company's views only as of the date of this press release and should not be relied upon as representing the Company's views as of any subsequent date. While the Company may elect to update forward-looking statements in the future, it specifically disclaims any obligation to do so, even if its expectations change. Therefore, you should not rely on these forward-looking statements as representing the Company's views as of any date subsequent to the date of this press release.

Aspect, Bispectral Index and BIS are registered trademarks of Aspect Medical Systems, Inc. All other trademarks, service marks and company names are the property of their respective owners.