Download - Preoperative Anesthetic Evaluation
Preoperative Anesthetic Evaluation
An Evidence Based Approach
Practice Parameters
Practice Guidelines
Practice Standards
Practice Advisories
Practice Guidelines
ASA Definition
“ Systematically developed recommendations for patient care that
described the basic management strategy or a range of management strategies”
Evolution of Evidence Based Guidelines
Prior to 1990 ………… consensus
Mostly practice standards
Not enough
How Do You Develop A Practice Guideline ?
Pick a Topic
Evaluate the Literature
Analyze
Consensus Opinion
Evidence
“Evidence based decision making in only as good as the evidence upon which it is based”
Wall Street Journal Article;Dec.15 2005
-Ghostwriters hired by Drug companies And
-Journal editors as Gatekeepers of medical literature
Practice Advisories
Insufficient literature evidence to support a guideline
Promotes and defines future research needs in a specific area
Guidelines are Not Laws
“ …nonbinding recommendations that may be adopted, modified, or
rejected according to clinical needs and restraints…”
Who Develops Guidelines ?
Anesthesia Professional societies
Specialty Colleges ( Amer. College of Cardiologists ) ( Amer. Heart Association )
Where to Find Guidelines
www.asahg.org www.anesthesiology.org
www. guideline.gov
What Constitutes a Preanesthetic Evaluation?
No Standard Definition
Components:
Medical Records ***InterviewExamMedical Tests and EvaluationConsultations
Purpose
Identify
Verify and Assess
Formulate Plan
Benefits Exceed Risks
Cancellation
Needed Delay
Plan
Safety
Injury
Discomfort
Inconvenience
Unnecessary Delay
Does Routine Testing Affect Outcome ?
Historically
1960’s
New technologies
Screening done independent of signs and symptoms
Decrease morbidity and mortality
ASA Advisory
General Advisory:
“Lack of benefit of routine testing”
Testing Parameters
For specific clinical conditions based on:
HistorySigns and symptoms
Nature of surgery ( type and invasiveness)
Surgery Specific Risk
HIGH emergency,vascular,peripheral
vascular,long surgeries with large fluid shifts or blood loss
INTERMEDIATE intraperitoneal,intrathoracic,CEA,head and neck,orthopedic,prostate
LOW endoscopic,cataract,breast,superficial
Surgeons
Kaplan et al., The Usefulness of Preoperative Laboratory Screening; JAMA, 2002
2236 Routine Lab Tests (Coags,CBC,Platelets,Diffs,Lytes,FBS)
65.6% - No indication
96 abnormals
4 clinically significant
Charpak et al., Prospective Assessment of a Protocal for Ordering a Preoperative Chest X-
Ray;Can. J. Anesth;1988
1101 Pre-op CXRs
5% (51) impacted surgical or anesth plan
Could have been predicted by history Smoker COPD
Cardiac condition
Age“Age alone is not an indication for
routine labs and testing”
ASA
Dzankic et al., The Prevalence and Predictive Value of Abnormal Laboratory Tests in Elderly
Surgical Patients; Anesth. Analg;2002
544 pts. > 70 yrs.old (elective)
6.8% Abnormal tests
Highest:
Creatinine 12% Hg 10% Predicted
physiologic Glucose 7% changes
Dzankic et al :
Risk Factors Predicted by: ASA > II Surgical Risk
Not Predicted by: Routine Labs/Tests
Schein et al., The Value of Routine Preoperative Medical Testing before Cararact Surgery, N.Eng.J.
Med; 2002
18,189 Cataract Procedures(2 Groups)
Routine Labs + EKG
EKG + Labs Indicated by H&P
Results:
NO Difference in outcome 31/1000: adverse events
ASA ADVISORY
“ Preoperative tests should not be ordered routinely… may be ordered, required,or performed on a selective basis for the purpose of guiding or optimizing perioperative management .“
ASA Feb ,2002
Timing of Preanesthetic Evaluation
Timing
Surgical Invasiveness
High
Medium
Low
- Prior to day
- Prior to day
- On or before
Physical Exam
Minimal:
Airway LungsHeart
Vital Signs
[ Documented ]
Acceptability of Previous Tests[within 6 months if medical condition same and
dependent upon plan ]
Consultants
EKG 99%CXR 97%Hg/Hct 99%Coags 86%Lytes 96%
General Membership Poll
98%92%96%98%98%
Suggestions for Specific Tests
(ASA Advisory)February 2002
“There is insufficient evidence for guidelines”
Electrocardiogram
No minimum age requirement
Surgical Invasiveness
Cardiac Risk factors and H&P Obesity Smoking Diabetes Couch Potato Family History etc……… Angina
EKG Changes Alter Care/Plan(Fleisher continued)
Arrythmias MI Heart blocks Ischemic ST changes LVH
Old MI Low voltage WPW Long QT Peaked T’s
H&P Findings Indicating EKG
Symptomatic Diabetes Advanced age Known CAD or Valvular Disease Low Functional Capacity Arrythmias
Surgical Procedure“Cardiovascular risk correlates with the
complexity of surgery” Fleisher
Ashton et al:
1487 elderly men
Vascular surgery 3 Times more
likely for post-op MI
Kumar et al:
7306 major surgery
4 to 6 times higher cardiac complications
ACC/AHA (2002)
EKG supported in:
Symptomatic Asymptomatic with DM Prior coronary revascularization Male >45y.o. Female > 55 y.o. with 2
or more risk factors Prior hospitalization for cardiac cause Unknown cardiorespiratory status
ACC/AHA (2007)
CLASS 1(ECG should be performed)
Vascular procedure with one or more risk factors
Known coronary,peripheral or cerebrovascular dz – intermediate risk surgery
CLASS II a
(Reasonable to consider)
No clinical risk factors Vascular procedure
CLASS II b
( May be reasonable to consider)
At least one clinical risk factor
Intermediate risk surgery
CLASS III( NOT indicated)
Asymptomatic
Low Risk procedure
Hg / HCT (ASA)
Not indicated routinely
Consider:Extreme age
Surgical procedureLiver disease
History anemia/bleedingHematological disorder
Hg/HCT (Fleisher)
No defined minimum HG as anesthetic or surgical risk factor
Predicts blood transfusion in surgeries typically involving high blood loss
Useful in hemodilution techniques
ASAConsider Hg/HCT
Surgery type Liver Dz. Extreme Age Anemia Bleeding or Blood disorders
Coagulation Studies(INR ,pt/ptt,platelets)
Needs more study/not enough data Before regional anesthesia Consider:
Bleeding disorderLiver diseaseMedications
Renal functionSurgical procedure
Anesthetic plan
Serum Chemistry(potassium,glucose,sodium,renal and liver
functions)ASA
“Normals vary greatly with age and disease state”
Routinely not indicated
Depends on disease state ,surgery, anesthetic plan
Urinalysis(ASA)
Not routinely indicated
Consider:Surgical procedure
Signs and symptoms of UTI
Pregnancy Testing(ASA)
(OLD) All females of childbearing age (NEW) …..may be offered to females of
childbearing age…… result would alter the patient’s management
Consent Issue Extremes
UCG vs. HCG
HCG - within 6 days of surgery
UCG – day of surgery
Chest X-Ray(ASA)
Consider:SmokerRecent URICOPDCardiac disease
Abnormal may be highest but are not prerequisites if stable.
Very dependent on surgical procedure
Conclusion
ASA states:
“ Guidelines and advisories may be adopted, modified or rejected according to clinical needs and restraints.”
Clinical judgement