Preoperative Medical Evaluation

							  Preoperative Medical
Evaluation/Consultation of
   the Healthy Patient
    Greg Rosencrance, MD
     2006 Nevada Chapter
      Scientific Meeting
    Saturday June 14, 2006
      Las Vegas, Nevada
    Principles of Consultation
 Determine the question
 Establish the urgency
 Gather data “look for yourself”
 Communicate briefly
 Make specific recommendations
 Understanding of the role
 Communicate directly
 Provide appropriate follow-up
             Compliance with
            Recommendations
 Improves with Brevity
 Predictors
             of illness
     Severity
     Type and number < 5

 Best with medications
 Worst with those requiring action
 Interaction with requesting physician
        Following of Patients
   Patients should be followed through the
    postoperative period. Perioperative MI’s
    peak at the 3rd to 5th days.
                   Clearance
   You are not “clearing” the patient for surgery

   Seek factors that may put the patient at higher
    than average risk and try to reduce these

   Risks are specific to the individual patient, type
    of procedure, type of anesthesia

   Average Risk
           Anesthesia Effects
   JAMA 1988, 100,000 procedures
            and surgical risk factors were more
     patient
     important than anesthesia factors
        duration
        experience   of operator
        inhalation techniques




                                    JAMA 1988;260:2859
             ASA or Dripps
   Considers mortality based on the general
    clinical impression

   Diagnose the severity of systemic illness

   Reproducible despite broadly defined
    categories
                 ASA Criteria
American Society of Anesthesiologists Classification of
                Preoperative Risk*
ASA             Systemic disturbance                    Mortality

 1         Healthy patient with no disease                <0.03
           percent outside of the surgical process

 2         Mild to moderate systemic disease                0.2
           percent caused by the surgical condition
           or by other pathological processes

 3         Severe disease process which                      1.2
           percent limits activity but is not incapacitating
                       ASA Criteria
ASA        Systemic disturbance                    Mortality

 4         Severe incapacitating disease process             8 percent
           that is constant threat to life

 5         Moribund patient not expected to survive         34 percent
           24 hours with or without an operation

 E         Suffix to indication emergency surgery            Increased
           for any class

 * Adapted from Cohen, MM, Duncan, PG, Tate, RB, JAMA 1988; 260:2859
               Anesthetic Risk
 Stress Responses
 Adverse and Idiosyncratic Reactions
     eg   malignant hyperthermia and hepatitis
   Organ system effects
     myocardial    depressants (preload dependent)
       dehydration
       autonomic   neuropathies
             Anesthetic Risk
   Effects of inhalational anesthesia
     decrease   in FRC with atelectasis and V/Q
      mismatch
     loss of sighs
     decreased mucociliary clearance
          Type of Anesthesia
   No difference in cardiac or overall
    perioperative mortality between general or
    spinal anesthesia

   Lower risk with minor regional anesthesia

   Since the type of anesthesia does not
    influence mortality, the medical consultant
    should not recommend a particular
    anesthetic technique
              Clinical Evaluation
      Preoperative Patient Questionnaire†
   Do you feel unwell?
   Have you ever had any serious illnesses in the past?
   Do you get any more short of breath with exertion
    than other people of your age?
   Do you have any coughing?
   Do you have any wheezing ?
   Do you have any ankle swelling?
   Have you taken any medicine or pills in the last three
    months (including excess alcohol)?
Clinical Evaluation (continued)
       Preoperative Patient Questionnaire*
   Have you any allergies?
   Have you had an anesthetic in the last two months?
   Have you or your relatives had any problems with a
    previous anesthetic?
   Observation of serious abnormality from “end of bed”
    which might affect anesthetic ?
   What is the date of your last menstrual period?

*Adapted from Wilson, ME, Williams, MB, Baskett, PJ, et al, BR Med J 1980; 1:509
            Exercise Capacity
   Ask all patients

   Two Blocks on level ground or carrying
    two bags of groceries up one flight of
    stairs without symptoms = 4 METS

   Average cardiac risk if they can perform
    these
                      Age
   Increased Risk with Increased Age

   50,000 elderly patients (elective)
     Under  60, 1.3% mortality
     80-89, 11.3% mortality




                                  Ann Intern Med 2001;134:637
                       Age
   795 patients over 90
     80%   ASA 3 or higher
     Survival at 2 years no different than controls
     Age alone should not be used as the sole
      criterion to withhold surgery




                                 Ann Intern Med 2001;134:637
       Laboratory Evaluation
   2000 pts undergoing elective surgery
     60%   would not have been performed if testing
      had been done for recognizable indications
     0.22% revealed abnormalities that might
      influence perioperative management
     May increase medicolegal risk




                                     JAMA 1985;253:3576
        Laboratory Evaluation
Probability of an Abnormal Screening Test Result
       Number of             Probability of
   Independent Tests         Abnormal Test
            1                   5 percent
           2                   10 percent
           4                   19 percent
           6                   26 percent
           10                  40 percent
           20                  64 percent
           50                  92 percent
   Laboratory Evaluation
Predictive Value of Positive Test Results

  Prevalence of        Predictive value of
 disease, percent     positive test, percent
        0.1                     1.9
        1.0                    16.1
        2.0                    27.9
        5.0                    50.0
       50.0                    95.0
       Laboratory Evaluation
 Probably safe to use labs that were
  performed and normal within the past 4
  months unless a change in the clinical
  status
 7549 preop tests in 1109 patients
     47%  duplicates within the prior year
     461 abnormal 78 (17%) of repeat values were
      outside accepted norms

                              Ann Intern Med 1990;113:969
       Laboratory Evaluation
   CBC
     Anemia  in 1% of asymptomatic patients
     Use as a baseline in patients expected to
      have significant blood loss
     No evidence to support baseline testing of
      WBC or Platelets




                                       JAMA 1985;253:3576
                   Laboratory
   Electrolytes
     0.6%   frequency of abnormality
     relationship between operative morbidity is
      unclear
     Routine determinations are not recommended




                                  JAMA 1985;253:3576
                 Laboratory
   Renal Function
     0.2%  prevalence of elevated creatinine if
      asymptomatic and no renal history
     prevalence increases with age
     46-60 9.8% prevalence
     Renal Insufficiency is associated with
      increased surgical morbidity
     reasonable to obtain Cr if > 50
                     Laboratory
   Glucose
     Abnormalities  increase with age
     25% of patients > 60 have an increase
     operative risk and diabetes
        vascular   or CABG
     Routine not rec prior to elective surgery
     Exceptions obese,steroids,FH
                  Laboratory
   LFT’s
     0.3%  of asymptomatic patients
     severe abnormalities increase morbidity
     not clear if mild abnormalities are similar
     Routine testing not recommended
                 Laboratory
   Hemostasis
     Routine  testing is not indicated
     Restrict to those with a known bleeding
      diathesis
                 Laboratory
   Urinalysis
     Relationship   between asymptomatic urinary
      tract infections and surgical infection is
      unclear
     4.58 wound infections in nonprosthetic knee
      operations may be prevented by the use of
      routine urinalysis.
     $1.5 million per wound infection prevented
                  Laboratory
   EKG
                  increase with age
     Abnormalities
     Unsuspected arrhythmias
       other than sinus, >5 PVC’s, PAC’s increases risk
        of perioperative cardiac events
     BBBdoes not increase the risk of cardiac
     complications following non cardiac sugery
                  Laboratory
   Electrocardiogram
     Unrecognized  myocardial infarctions are
      relatively common
     Framingham study
       5127  participants, 708 MI’s, 25% were identified
        only via routine EKG
       Proportion of unrecognized infarcts higher in
        women and older men
          EKG Guidelines
 Men > 40
 Women > 50
 Known cardiac disease
 Clinical Evaluation suggesting the
  possibility of cardiac disease
 Patients at risk for electrolyte
  abnormalities
          EKG Guidelines
 DM, HTN
 Major Surgical Procedures
                  Chest X-Ray
 Add little
 905 surgical admissions
     screened    for risk factors for abnormal preop
     CXR,
       age>60,   clinical findings c/w cardiac or pulmonary
        disease
       no risk factors in 368, 1 (0.3%) had an abnormal
        cxr which did not affect surgery
                 Chest X-Ray
   504 had identifiable risk factors
     114   (22%) had significant abnormalities
   Meta analysis 21 studies
     14,390  routine cxr
     1444 abnormal, 140 unexpected, 14 ( 0.1%)
      influenced management
   CXR not routinely performed unless > 60, or
    suspected cardiac or pulmonary disease
    Pulmonary Function Tests
 Not routinely recommended for healthy
  patients
 ACP recs:
         resection surgery, CABG, upper
     lung
     abdominal surgery w/tobacco history, head
     and neck or orthopedic surgery w/
     uncharacterized pulmonary disease
               Summary
 Screening questionnaire for all patients
 History of exercise tolerance for all
 BP and pulse for all
 H&P if one of the above is abnormal, > 60,
  or major surgery
 Pregnancy test for women who may be
  pregnant
 Hg if suspected major blood loss
                Summary
 Creatinine if hypotension is suspected,
  nephrotoxic drugs, > 50
 EKG unless within 1 month criteria as
  stated
 CXR if > 60, suspected disease unless
  within 6 months
 PFT’s per ACP position statement
 All other tests only if clinical evaluation
  suggests a likelihood of disease