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