Volume 2, No. 1 • Spring 1987

American Society of Anesthesiologists Standards for Basic Intra-Operative Monitoring

(Approved by House of Delegates on October 21, 1986)

These standards apply to all anesthesia care although, in emergency circumstances, appropriate fife support measures take precedence. These standards may be exceeded at any time based on the judgment of the responsible anesthesiologist. They are intended to encourage high quality patient cam but observing them cannot guarantee any specific patient outcome. They are subject to revision from time to time, as warranted by the evolution of technology and practice. This set of standards addresses only the issue of basic intra-operative monitoring which is one component of anesthesia cam In certain mm or unusual circumstances,

1) some of these methods of monitoring may be clinically impractical, and

2) appropriate use of the described monitoring methods may fad to detect untoward clinical developments. Brief interruptions of continual monitoring may be unavoidable under extenuating circumstances, the responsible anesthesiologist tiny waive the requirements marked with an asterisk (*), it is recommended that when this is done, it should be so stated (including the reasons) in a note in the patient’s medical record. These standards are not intended for application to the care of the obstetrical patient in labor or in the conduct of pain management.

Note the “continual” is defined as “repeated regularly and frequently in steady succession” whereas “continuous” means “prolonged without any interruption at any time”


Qualified anesthesia personnel shag be present in the room throughout the conduct of all general anesthetics, regional anesthetics and monitored anesthesia care.


Because of the rapid changes in patient status during anesthesia, qualified anesthesia personnel shad be continuously present to monitor the patient and provide anesthesia cam In the event there is a direct known hazard, e.g., radiation, to the anesthesia personnel which might require intermittent remote observation of the patient, some provision for monitoring the patient must be made. In the event that an emergency requires the temporary absence of the person primarily responsible for the anesthetic, the best judgment of the anesthesiologist will be exercised in comparing the emergency with the anesthetized patient’s condition and in the selection of the person left responsible for the anesthetic during the temporary absence.


During all anesthetics, the patient’s oxygenation, ventilation, circulation and temperature shall be continually evaluated.


To ensure adequate oxygen concentration in the inspired gas and the blood during all anesthetics.


1) Inspired gas: During every administration of general anesthesia using an anesthesia machine, the concentration of oxygen in the patient breathing system shall be measured by an oxygen analyzer with a low oxygen concentration limit alarm in use.

2) Blood oxygenation: During all anesthetics, adequate illumination and exposure of the patient is necessary to assess color. While this and other qualitative clinical signs may be adequate, there are quantitative methods, such as pulse oximetry, which are encouraged.


To ensure adequate ventilation of the patient during all anesthetics.


1) Every patient receiving general anesthesia shall have the adequacy of ventilation continually evaluated. While qualitative clinical signs such as chest excursion, observation of the reservoir breathing bag and auscultation of breath sounds may be adequate quantitative monitoring of the C02 content and/or volume of expired gas is encouraged.

2) When an endotracheal tube is inserted, its correct positioning in the trachea must be verified. Clinical assessment is essential and end-tidal C02 analysis, in use from the time of endotrachial tube placement, is encouraged.

3) When ventilation is controlled by a mechanical ventilator, there shall be in continuous use 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.

4) During regional anesthesia and monitored anesthesia cam the adequacy of ventilation shall be evaluated, at least, by continual observation of qualitative clinical signs.


To ensure the adequacy of the patient’s circulatory function during all anesthetics.


1) Every patient receiving anesthesia shag have the electrocardiograrn continuously displayed from the beginning of anesthesia until preparing to leave the anesthetizing location.

2) Every patient receiving anesthesia shag have arterial blood pressure and heart rate determined and evaluated at least every five minutes.

3) Every patient receiving general anesthesia shall ham in addition to the above, circulatory function continually evaluated by at least one of the following; palpation of a pulse, auscultation of heart sounds, monitoring of a tracing of intra-arterial pressure ultrasound peripheral pulse monitoring, or pulse plethysmography or oximetry.


To aid in the maintenance of appropriate body temperature during all anesthetics.


Them shall be readily available a means to continuously monitor the patient’s temperature When changes in body temperature are intended, anticipated or suspended, the temperature shag be measured.