Audible Information Signals (‘Alarms’) and Their Role in the Operating Room

Monitoring a patient’s physiologic function during anesthesia is intended to facilitate, but not replace, the constant vigilance of the anesthesiologist. In this regard, monitors may be viewed as adding an “additional safety net” for the vigilant anesthesiologist. Since the adoption of ASA’s Standards for Basic Anesthetic Monitoring by the House of Delegates on October 21, 1986, there has been an evolution of monitoring technology and consensus among anesthesiologists, which is reflected by the amendment of these monitoring standards on October 21, 1998, to include pulse oximetry and capnography.¹

The existing Standards for Basic Anesthetic Monitoring include “… an oxygen analyzer with a low oxygen concentration limit alarm …” and “… use of a device that is capable of detecting disconnection of components of the breathing system. The device must give an audible signal when its alarm threshold is exceeded.”¹ Since these standards were last amended, the development and availability of audible information signals as part of the physiologic monitors have continued to evolve. Furthermore one of the 2003 Joint Commission on Accreditation of Healthcare Organizations’ (JCAHO) National Patient Safety Goals is to “Improve effectiveness of clinical alarm systems.”² This JCAHO safety goal includes the statement: “Assure that alarms are activated with appropriate settings and are sufficiently audible with respect to distances and competing noise within the unit.”² JCAHO’s suggestions for meeting this goal and its recommendations are to “develop and implement policies that prevent turn-off capabilities for alarms.”² In a report of 1,000 anesthetic incidents, the fact that an “alarm sounded” was recognized as one of the most important factors in minimizing the severity of the incident.³

Despite the compelling logic for utilizing audible information signals to enhance the anesthesiologist’s vigilance, the reality is that audible physiologic alarms may be viewed as distractive and disruptive by physicians, leading to the routine practice of “silencing” the alarms.⁴ Audible alarms may not provide valid physiologic information and can be associated with patient interventions and events already known by the anesthesiologist. Furthermore how many audible alarms (and their variety of tones) are really needed? These questions have led the Anesthesia Patient Safety Foundation (APSF) to announce the following initiative:

APSF will publish, in a future edition of the APSF Newsletter, a discussion of the use of audible alarms on physiological monitors and the use of audible beep tone from the pulse oximeter during all anesthetics. In addition, APSF will sponsor an APSF Board of Directors’ workshop on this topic on October 22, 2004, in Las Vegas, Nevada.

Although the announced APSF initiative is focused on operating rooms, the intent is for the discussion to extend beyond the operating room to include high-acuity monitoring areas in the hospital. APSF will solicit input from anesthesiologists and the equipment industry to better understand the value (and flaws) of existing audible information signals and establish how improvements can be made to decrease the perceived disruption and distraction that may be created by existing audible alarms.

Ultimately any change in monitoring standards that speaks to the use of audible alarm signals will be based on consensus and cooperation between anesthesiologists and those who manufacturer monitors that incorporate audible information signals in physiologic monitors.

It is my personal bias that the audible presence of the “beep” tone from a pulse oximeter — plus knowing that the audible alarm on at least one physiologic monitor of the anesthesiologist’s choice (oxygen saturation, end-tidal carbon dioxide, heart rate, blood pressure) is active — would provide the desired safety net to the anesthesiologist’s eternal vigilance without the distraction that may be created by a “chorus” of alarms sounding without valid physiologic reasons.

APSF intends to provide the forum for these discussions and urges input from anesthesiologists and manufacturers on this important anesthesia patient safety question.


References:

1. American Society of Anesthesiologists (ASA) Standards for Basic Anesthetic Monitoring (Approved by House of Delegates on October 21, 1986, and last amended on October 15, 2003). ASA Standards, Guidelines and Statements. October 2003:5-6. <www.ASAhq.org/publicationsAndServices/standards/02.pdf#2>.

2. 2003 Joint Commission on Accreditation of Healthcare Organizations National Patient Safety Goals: Practical Strategies and Helpful Solutions for Meeting These Goals. <www.jcaho.org/accredited+organizations/patient+safety/npsg.htm>.

3. James RH. 1,000 anaesthetic incidents: Experience to date. Anaesthesia. 2003; 58:856-863.

4. Block FE, Nuutinen L, Ballast B. Optimization of alarms: A study on alarm limits, alarm sounds and false alarms intended to reduce annoyance. J Clin Monit Comput. 1999; 15:75-83.

Robert K. Stoelting, M.D., Indianapolis, Indiana, is President of the Anesthesia Patient Safety Foundation.