Chapter 93: ASA Monitoring Standards

PRINCIPLES OF MONITORING

Because of the possibility of frequent alterations of patient vital signs and physiology due to the administration of anesthesia, the anesthesiologist must monitor the patient to assess for problems and allow for ample time to intervene. One must apply monitors, observe, and interpret the data, as well as begin appropriate treatment when necessary. The purpose of monitoring is to promote optimal care of the patient and notice trends and abnormalities before they become irreversible. Even so, following these guidelines does not ensure any particular outcome for patients.

The American Society of Anesthesiologists (ASA) has developed Standards for Basic Anesthetic Monitoring, which was last updated in 2011. According to this document, an authorized anesthesia provider must remain with a patient throughout the duration of any general, regional, or monitored anesthesia care, to administer anesthesia and monitor the patient. In some instances, short lapses in monitoring may occur and are sometimes inevitable. For certain patients, particular monitoring techniques may be unfeasible. In the rare situation where there is an exposure or danger to the anesthesia care provider, distant discontinuous monitoring may be necessary. If there is an emergency that would require the anesthesia provider to temporarily leave the patient, the anesthesiologist must determine the importance of the emergency and its effect on the patient. The anesthesiologist must also decide who will continue to deliver the anesthetic and monitor the patient until the anesthesia care provider is able to return.

These standards apply to patients receiving monitored anesthesia care, general anesthesia, as well as regional anesthesia. These standards do not necessarily apply to obstetrical patients or pain management patients. It is also the anesthesiologist’s responsibility to determine if additional monitoring is required beyond the basic monitors.

The ASA Standards for Basic Anesthetic Monitoring emphasizes the assessment of a patient’s circulation, oxygenation, ventilation, and body temperature:

Circulation

It is important to monitor the patient’s circulation while under anesthesia. Every patient must have a blood pressure and heart rate assessed at least every 5 minutes. Patients must also have an electrocardiogram continually assessed from the start of the anesthetic until the patient leaves the operating or procedure room. Lastly, patients under general anesthesia are also required to have assessment of circulation continuously by an additional method. The possible methods are pulse oximetry, intraarterial blood pressure monitor, auscultation of patient’s heart, feeling of patient’s pulse, or peripheral pulse assessment with ultrasound.

Oxygenation

The anesthesia provider must assess that the patient has sufficient oxygen concentration in inspired gas and blood. During any general anesthetic that utilizes an anesthesia machine, an oxygen analyzer must be used to evaluate the concentration of oxygen in the breathing circuit. The machine must have a working low oxygen concentration limit alarm.

During any type of anesthesia, blood oxygenation must be measured by certain ...