Principles of Basic Preoperative Testing
at University of Wisconsin Hospital
(File last saved:
11/4/04
)
PAC Home | Basic
Testing | Specific Disease Testing
- "Screening" vs. "Criteria" Based
Tests:
"Screening" refers to testing patients who are both asymptomatic
and have no physical signs of disease. However, symptoms or physical signs
may be insensitive indicators of some diseases. Symptoms are especially
insensitive when physiologic "stress" is low (e.g. patient is sedentary)
and there is a wide margin of reserve (such as in the respiratory and cardiac
systems). Screening guidelines constantly undergo revision and may be difficult
to devise without becoming too simplistic or complex. Factors such as the
prevalence of the disease in the population, the medical and financial impact
of missing a "problem," the
cost per problem found, financial reimbursement, and societal judgments
determine
when" screening" tests are indicated. Tests should not usually
be performed preoperatively without, at least, some criteria based on the
patient, the surgery, and the anesthesia. See Basic
Criteria Testing. Optimally efficient testing entails considering a combination
of criteria including:
- The age, gender, & reporting reliability of the patient. For
example: older or less reliable patients may be more likely to have an
unsuspected abnormality picked up by a "screening" test.
- The surgical procedure. Very minor procedures are
likely to be tolerated well by most patients. Major procedures, however,
are associated with significant physiologic stress. Existing medical
conditions which may be of little concern during a brief and minor procedure
may cause significant problems during (and after) a long and/or complex
surgery. Testing should reflect this need for an increased level of evaluation,
preparation, monitoring, and postoperative care.
- The type of anesthesia. For some procedures done WITHOUT general
anesthesia, fewer tests MAY be needed. However, it should be remembered
that conversion to a general anesthetic may occur due to unforeseen
circumstances.
- "Problem Focused" Tests: Specific
medical problems, or suspected problems detected during the H&P, may warrant
further testing (see Specific Conditions
table). Again, a patient who is a poor historian may need more extensive
testing than would otherwise be indicated on the basis of #1 above.
- Previously performed tests MAY be acceptable
for preoperative preparation. Some may be acceptable beyond time periods
listed below, but only at the discretion of the Preoperative Anesthesiology
Assessment Clinic (PAAC).
- CXR: done within 6
MONTHS is
acceptable IF it was normal, or showed a stable condition. This means
that if there has been a change in the interim, the CXR may need
to be repeated.
Check with the PAAC if there are any questions.
- ECG: done within 6
MONTHS is acceptable IF it was normal, or showed a stable condition. This
means that if there has been a change in the interim, the ECG may
need to be repeated. Check with the PAAC if there are any questions.
- Blood Tests: done within
6 WEEKS are acceptable IF normal, or showed a stable condition.
This means that if there has been a change in the
interim, the lab tests may need to be repeated. Check with the PAAC if
there are
any questions.
