The Doctor’s Advocate | Second Quarter 2014
An Ounce of Prevention
Why Accuracy Matters
by Susan K. Palmer, MD, The Doctors Company Anesthesia Advisory Board Member
In 1940, a committee formed by the American Society of Anesthetists, the predecessor to today’s American Society of Anesthesiologists (ASA), first developed a system for classifying the medical condition of a patient before surgery. The six-category classification system described only the patient’s physical state before surgery began; it did not attempt to predict the risks for any particular type of surgery.1
In 1961, the categories were revised to a five-class system.2 In 1974, the ASA House of Delegates revised and published the five-class system that most anesthesiologists use today.3
One important difference between the 1974 and current classification systems is that, originally, a Class 5 patient was described as “a moribund patient who is not expected to survive 24 hours with or without the operation.” Some anesthesiologists may still be using this original wording from the five-class system. Here is the current ASA Physical Status (PS) Classification System with the updated Class 5 wording:
ASA PS 1, a normal, healthy patient.
ASA PS 2, a patient with mild systemic disease.
ASA PS 3, a patient with severe systemic disease.
ASA PS 4, a patient with severe systemic disease that is a constant threat to life.
ASA PS 5, a moribund patient who is not expected to survive without the operation.
ASA PS 6, a declared brain-dead patient whose organs are being removed for donor purposes.
(Note: Class 6, added to describe an organ donor, does not correctly classify a moribund patient who is brought to the OR for withdrawal of ICU support and immediate organ donation. This type of patient should be declared dead by the intensivist, who withdraws support in the OR and determines the time of death as the time when heart activity ceases.)
From its inception, the PS classification of patients has been used in retrospective analyses of morbidity and mortality.4 Although the classification system does not contain exact definitions, and even though there can be some honest disagreement among board certified anesthesiologists,5 the system is still valuable because it reflects the overall judgment of an experienced anesthesia provider about a patient’s condition before surgery.
Capturing Data on Anesthesia Care
Approximately 80 percent of hospitals in the United States do not have integrated data capture systems that incorporate the electronic recordings of anesthesia care. The data about anesthesia decisions and complications from these hospitals will be useful in proportion to the accuracy of the hand-recorded judgments of anesthesia providers. Any anesthesia provider or sedationist who seriously misclassifies a patient will appear to have made poorly informed decisions about a patient. As an example, some healthcare organizations (HCOs) require the use of the ASA PS Classification System to measure the suitability of a patient for procedures within a facility. If a Class 4 patient is categorized as Class 2 to, apparently, circumvent facility or medical staff rules, the decision could later be criticized as self-evident poor judgment.
The Continuum of Sedation
Just as it is fundamentally important to assign a correct physical class to a patient, it is also imperative that the anesthetic techniques used for a patient be accurately recorded. The availability of propofol and other short-acting drugs for sedation has created some confusion in the terminology used by surgeons and anesthesia providers.
If a surgeon requests “MAC” (monitored anesthesia care), the anesthesia provider must know or find out exactly what techniques of anesthesia care the surgeon will expect for the planned procedure. The ASA composed the continuum of sedation definitions to aid anesthesia providers (and others who want to offer sedation services). The continuum was devised to clarify the fact that patients can respond to sedation drugs with a range of conscious and unconscious states, respiratory instability, and cardiac instability. Which drugs and doses produce comfortable and stable patients depends most importantly on the procedural stimuli and on the patient’s preprocedure medical conditions. Hence, many HCOs require the use of the ASA’s PS Classification System to identify patients who are suitable candidates for sedation.
Some confusion exists among procedural specialists about when sedation becomes general anesthesia. The ASA worked with other professional societies to produce a continuum of sedation that defines the four levels:
Minimal sedation: patient alert, immediately responsive to voice requests.
Moderate sedation: purposeful responses to voice; stable heart rate (HR) and respiratory rate (RR).
Deep sedation: requires repeated stimulation for purposeful response; may have unstable HR, blood pressure (BP), or RR. Reflex withdrawal is not a purposeful response.
General anesthesia: unarousable, possible reflex withdrawal to painful stimulation; HR, BP, and RR often affected.
The continuum of sedation was developed to emphasize the fact that patients may be in more than one level of sedation during a procedure. Monitoring is required because the planned level of sedation can easily slip into a deeper and less physiologically stable level.
Defining General Anesthesia
Anesthesia terms that are no longer acceptable include “conscious sedation,” the surgeon’s favorite “big MAC,” and the undefined “heavy sedation.” The definition of MAC has gone through several politically and financially motivated changes in description. Since 2003, the ASA has defined general anesthesia as any sedation during which a patient becomes unresponsive for any period of time, irrespective of whether airway instrumentation is required.6 For instance, if a patient is placed into deep sedation for the injection of a retrobulbar block and responds minimally during that normally painful injection, the anesthetic technique would be correctly recorded as general anesthesia. If the sedation is entirely provided with intravenous drugs, the most descriptive term would be intravenous general anesthesia.
Currently, many anesthesia records and hospital records are inconsistent about the type of anesthesia care actually performed. For instance, the hospital record may state that the surgeon requested monitored anesthesia care, but the anesthesia record shows that intravenous general anesthesia was actually provided.
Why Accurate and Consistent Anesthesia Records Matter
It is essential for anesthesia providers to accurately and consistently record the techniques they use in caring for individual patients and to provide precise descriptions of the planning and work they perform.
The accumulated data is important for all patients, who will eventually benefit from the study of anesthesia records, process variables, and subsequent outcomes. It is also important because, ultimately, the data will be used in making political and reimbursement decisions that will affect all anesthesia providers and HCOs.