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Updated: Aug 23 2017

Preoperative Evaluation

Snapshot
  • A 62-year-old man with hypertension, type II diabetes, and a 20-pack year history of smoking is scheduled for elective left total hip arthroplasty (THA). He comes to your clinic stating that he recently suffered an acute MI 6 weeks ago. He requires further evaluation with an EKG, stress test and 2D echo. You also inform his orthopaedic surgeon that the surgery will have to be deferred for more than 6 months. You advise him to stop smoking, and prescribe him a nicotine patch in the meantime. 
 
General Evaluation
  • Patients undergoing surgery must be medically optimized prior to surgery
  • The most common limiting factor prior to surgery is cardiovascular disease
  • CBC
    • for patients undergoing procedures with risk of blood loss
  • Electrolytes, BUN and creatinine 
    • patients > 60yrs
    • have comorbidities (e.g. diarrhea, renal disease, liver disease)
    • on medications predisposing to electrolyte abnormalities (e.g. diuretics) 
  • PT and PTT 
    • patients with bleeding diathesis (e.g. hemophilia, on warfarin)
    • liver disease (may affect clotting factor production)
    • undergoing neurosurgery or cardiac surgery (where excess bleeding will affect surgical outcome)
  • Chest radiograph
    • preexisting pulmonary problems (e.g. COPD, chronic smokers, pulmonary fibrosis)
    • increased risk of pulmonary complications (e.g. obesity)
    • thoracic surgery
  • EKG
    • men > 40yrs
    • women > 50yrs
    • young patients with pre-existing cardiac disease (e.g. arrhythmia)
Cardiovascular Disease Risk Assessment
  • Conditions that a patient must undergo evaluation and treatment before noncardiac surgery (ACC/AHA 2007 Guidelines)  
    • unstable coronary syndromes
      • unstable or severe angina (CCS class III or IV)
        • may include “stable” angina in patients who are unusually sedentary
      • recent MI
    • decompensated HF: (NYHA functional class IV; worsening or new-onset HF) 
    • significant arrhythmias
      • high-grade atrioventricular block
      • mobitz II atrioventricular block
      • third-degree atrioventricular heart block
      • symptomatic ventricular arrhythmias
      • supraventricular arrhythmias (including atrial fibrillation) with uncontrolled ventricular rate (HR greater than 100 bpm at rest) 
      • symptomatic bradycardia
      • newly recognized ventricular tachycardia
    • severe valvular disease
      • severe aortic stenosis (mean pressure gradient greater than 40 mm Hg, aortic valve area less than 1.0 cm2, or symptomatic) 
      • symptomatic mitral stenosis (progressive dyspnea on exertion, exertional presyncope, or HF)
  • Ejection fraction < 35% increases risk in non-cardiovascular surgery
  • Investigations
    • < 35 years, no ischemic heart disease (IHD)
      • requires EKG only
    • history of IHD (regardless of age) require:
      • EKG
      • stress test
      • 2D echo for structural disease and to assess ejection fraction
  • Management
    • CHF
      • optimize patient with ACE inhibitors, beta blockers and spironolactone to decrease mortality
    • recent acute myocardial infarction
      • if < 6 months, then defer surgery for 6 months 
      • obtain stress test during this period 
Pulmonary Disease Risk Assessment
  • Investigations
    • known lung disease, smoking history, or thoracic surgery 
      • obtain pulmonary function testing 
  • Management
    • smoking cessation
      • should quit 6-8 weeks before surgery and use nicotine patch in the meantime
 Renal Disease Risk Assessment
  • Investigations
    • urinalysis in patients undergoing urologic surgery
  • Management
    • give fluids before and during surgery
      • patients with renal disease must be kept hydrated to reduce kidney hypoperfusion, which will affect remaining kidney function and increases mortality
    • if patient is on dialysis, dialyze 24-hours before surgery
Evaluation of Bleeding Disorders
  • History (or family history) suggestive of bleeding disorders which includes
    • bleeding following minor trauma (e.g. cuts, large hemarthrosis after minor falls)
    • heavy menses
    • bleeding after medical procedures (e.g. dental procedures, previous surgery)
    • sequelae of liver disease
    • medication (e.g. NSAIDS and herbal medications (ginko, ginseng and garlic) which affect platelets and increase bleeding complications
  • Investigations
    • bleeding time
      • assesses platelet function
      • indicative of qualitative or quantitative platelet defect
      • also increased in von Willibrand's disease and vasculitis
    • prothrombin time
      • time to clot after addition of thrombin 
        • thrombin converts fibrinogen to fibrin
      • increased thrombin time
        • increased fibrin
        • dysfibrinogenemia
        • DIC
        • heparin administration
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