Preoperative Evaluation 7-7-06

8/13/2019 Preoperative Evaluation 7-7-06

http://slidepdf.com/reader/full/preoperative-evaluation-7-7-06 1/18



Definition of Post-Op PulmonaryComplications

Pulmonary abnormality that producesidentifiable disease or dysfunction that isclinically significant and adversely affects the

clinical course



Categories of Clinically SignificantComplications

AtelectasisInfection, including bronchitis and pneumonia

Prolonged mechanical ventilation andrespiratory failureExacerbation of underlying chronic lung disease

Bronchospasm



Peri-operative lung physiology Thoracic and Abdominal Surgery

Vital capacity (VC) is reduced by 50 to 60 percent and mayremain decreased for up to one week Functional residual capacity (FRC) is reduced by about 30percent

Diaphragmatic dysfunction appears to play the most important role inthese changesReduction of the FRC below closing volumes contributes to the risk ofatelectasis, pneumonia, and ventilation/perfusion (V/Q) mismatching

Residual effects of anesthesia itself and postoperative

opioids both depress the respiratory drive

Inhibition of cough and impairment of mucociliary clearance-Increased risk of infection





Pre-operative Risk Assessment

Complete H&P is most important tool for evaluation & riskassesement

Significant risk factors should be identified

Physical examination should be directed toward evidence forobstructive lung disease Laboratory tests serve as adjuncts to the clinical evaluation andshould be obtained only in selected patients

Pulmonary function tests (PFTs) Arterial blood gas analysisChest radiographsExercise testing



Recommended Strategies

Preoperative StrategiesSmoking cessation for 8 weeksInhaled ipratropium for all patients with clinically significantCOPD

Inhaled beta-agonists for patients with COPD or asthma whohave wheezes or dyspneaPreoperative corticosteriods for patients with COPD orasthma who are not optimized to best baseline and whose

airway obstruction has not been maximally reducedDelay elective surgery if respiratory infection present

Antibiotics for patients with infected sputum



Recommended Strategies Cont.

Intraoperative StrategiesChoose alternative procedure lasting less than 3 to 4 hours when possibleMinimize duration of anesthesiaSurgery other than upper abdominal or thoracic whenpossibleChoose laparoscopic rather than open abdominal surgery

when possibleRegional anesthesia (nerve block) in very high-risk patientsEpidural or spinal anesthesia in lieu of general anesthesia inhigh risk patients

Avoid use of pancuronium as a muscle relaxant in high riskpatients



Recommended Strategies Cont.

Postoperative StrategiesDeep breathing exercises or incentive spirometry in high riskpatientsEpidural analgesia in lieu of parenteral opioids

Continuous positive airway pressure (CPAP)





Perioperative Cardiac Risk

Each year approximately 50,000 patients haveperioperative MI’s, and about 40% of them willdieMost perioperative MIs occur without thetypical chest pain, due to analgesics after surgery,residual effects from the anesthesia, and otherperioperative painful stimuli



Periop Cardiac Risk

In studies evaluating incidence of MI aftergeneral anesthesia for patients who previouslyhad an MI within 3 months, there was a

reinfarction rate of 27-37%. Reinfarction was11-16% for those who had an MI 3-6 monthspreviously.Reinfarction rate remained stable at 5% forthose who had an MI >6 months previous tosurgery.



In 1977 Goldman and colleagues developed apreop cardiac risk index for patients undergoingnon-cardiac surgery. They reported nine

variables associated with an increased risk forperioperative cardiac complications.

Each risk factor was assigned a point score, andpatients were stratified into four risk categoriesbased on their total points.



Goldman Preop Cardiac Risk Index3rd Heart sound (S3) 11Elevated JV pressure 11MI in past 6 months 10ECG: premature atrial contractionsor any rhythm other than sinus

7

ECG shows >5 premature

ventricular contractions per minute 7

Age >70 years 5

Emergency Procedure 4Intra-thoracic, intra-abdominal or

aortic surgery 3

Poor general status, metabolic or

bedridden 3

9 Individual riskfactors and theirscores are asfollows:





Detsky’s Modified Cardiac RiskIndex

In 1986 Detsky and colleagues modified theoriginal multifactorial index by adding variablessuch as angina and pulmonary edema.Patients are stratified into three risk categoriesbased on their total points



Age older than 70 years 5MI within 6 months 10MI after 6 mo previously 5Canadian CV society anginaClassification:Class III

10

Class IV 20Unstable angina in past 6mo

10

Alveolar Pulm Edema: inpast week 10

Alv. Pulm Edema: Ever 5

Suspected Critical AorticStenosis

20

Arrhythmia: Rhythm otherthan sinus or atrial prematurebeats

5

More than 5 premature ventricular beats

5

Emergency Operation 10Poor General Medical Status 5

Class Points RiskI 0-15 LOWII 20-30III 31+ HIGH



ACPguidelines

Documents

Preoperative Evaluation 7-7-06