Further Changes in Basic Monitoring Standards Proposed

John H. Eichhorn, M.D.

Amendments Up for Vote

Coming on the heels of last year’s vote by the ASA House of Delegates to amend the ASA Standards for Basic intraoperative Monitoring to mandate pulse oximetry, two newly proposed related changes are slated for consideration this October.

The O.R. oximetry amendment that went into effect January 1, 1990 built on the distinction between qualitative (observation) and quantitative (measurement) monitoring. Previously, quantitative monitoring was only “encouraged.” Now, the current standard regarding blood oxygenation reads: “During all anesthetics, a quantitative method of assessing oxygenation such as pulse oximetry shall be employed. Adequate illumination and exposure of the patient is necessary to assess color.” Due to the virtual absence of popular competing technologies, intraoperative pulse oximetry was functionally made the standard of care by this actions of the ASA at its last annual meeting.

PACU Oximetry

This year, them is a proposal from the Committee on Standards of Care to amend the Standards for Postanesthesia Care originally approved in 1988 to extend essentially mandatory pulse oximetry into the PACU. The current standard mandates continual evaluation of the patient while in the PACU and calls for observation and monitoring by methods appropriate to the patient’s condition. Again noting the distinction, the standard now reads: “While qualitative clinical signs may be adequate, quantitative methods are encouraged. The amendment would add: “During recovery from all anesthetics, a quantitative method of assessing oxygenation such as pulse oximetry shall be employed:’

This change emphasizing the use of pulse oximeters in the PACU was initiated by two developments: 1) significantly increased use of pulse oximetry in the PACU, moving the practice towards a de facto standard of cam paralleling what happened in the O. R.; and, 2) information from the ASA Closed Claim Study, insurance carriers, and other sources to the effect that hypoxic injuries in the PACU continue to occur and may, in fact, be increasing. Further, some members of the committee suggested that the average patient may actually be at greater risk in the PACU than in the O.R., making the continuation of pulse oximetry during this vulnerable time both logical and desirable. The ASA Board of Directors has proposed an effective date of January 1, 1992 for amendment to the standards.

Information input similar in type to that outlined above led to the second proposed change, which would again add to the Standards for Basic Intraoperative Monitoring, this time relative to verification of endotracheal tube placement. Specifically, the ASA Closed Claims Study revealed a continued significant incidence of unrecognized esophageal intubation and consequent patient injury at a time when other types of major incidents seemed to be dramatically decreasing. In addition, Fred Cheney, M. D., Chairman of the ASA Committee on Professional Liability, noted that in a great many of those circumstances, the practitioners involved had ausculted the chest and believed that there were breath sounds indicative of correct endotracheal tube placement even though the tube was later found to be in the esophagus.

Under “Ventilation,” the existing intraoperative monitoring standards state: “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 endotracheal tube placement, is encouraged. The committee deliberated how potentially to strengthen this standard while still recognizing that capnography is not universally in place. Practical and economic realities led the committee to stop short of proposing mandatory capnography. Since the issue is correct endotracheal placement, the focus became identification of expired C02

It was recognized that capnography is one effective, popular way to identify expired C02, but that there is also at least one other method available that does not require the capital outlay for capnographs. Therefore, the proposed modification states that endotracheal tube positioning “must be verified by clinical assessment and by identification of carbon dioxide in the expired gas. Continuous capnography is still “encouraged.” It was felt by the committee that the compromise will enhance patient safety relative to unrecognized esophageal intubations but leaves enough leeway to cover all circumstances. Currently, the proposed effective date of this change in the standard is “as soon as feasible, but in no case later than January 1, 1991.”

Burton S. Epstein, M.D., Chairman of the ASA Committee on Standards of Care which proffered the two standards changes, noted the long lead time on the PACU pulse oximetry implementation. He said, “it is valid to consider how rapidly hospitals and anesthesiologists can tool up to implement these upgraded PACU standards”. Further, Dr. Epstein commented that the misconception about whether tmaboutwhetherthis standard should apply to women recovering after regional anesthesia for normal vaginal delivery, particularly because it has been thought by some obstetric anesthesiologists not to be necessary.

Regarding the proposal of C02 identification for verification of endotracheal tube placement, Dr. Epstein did enter a caveat about potential confusion in the clinical setting when the tube is, in fact, in the trachea but there is no cardiac output to carry C02 to the lungs. He stated a question had been raised about cardiac arrest situations and the possible mistaken removal of a correctly placed tube.

These two 1990 proposals will be considered at the ASA annual meeting. Reference Committee hearings will be held Saturday, October 20 and all interested parties are invited to attend and testify if desired. The Reference committee resultant recommendations will be considered by the delegate caucuses and then the House of Delegates will address the proposals at its meeting Tuesday, October 22.

Dr. Eichhorn, Harvard Medical School, is editor of the APSF Newsletter and also a member of the ASA Committee on Standards of Care.