LABORATORY STUDIES


See also "Screening for Coronary Artery Disease and other cardiac disease preoperatively"

  1. Coag studies: h/o bleeding problems, liver dis., malnutrition or malabsorption, recent or current active bleeding, on anticoagulants, can't give hx
  2. Hemoglobin: signs or sx of anemia, any procedure ass'd with major blood loss; pregnancy, renal insufficiency, h/o cancer, cardiac disease, diabetes, institutionalized pts >75yo, recent immigrants.
  1. Surg. risk in increased if Hb < 8-10
  1. Potassium: diuretic Rx, diarrhea, renal insufficiency, diabetes, > 60yo, can't give hx
  1. Hypokalemia appears to increase the risk of perioperative arrhythmia, at least in cardiac surgery patients (JAMA 281:2203, 1999--JW)
  1. BUN & Creatinine: renal insufficiency, cardiac disease, diabetes, HTN, severe liver disease, >50yo, SIADH, diabetes insipidus.
  1. Increased risk for ARF if pre-op Cr >1.2
  1. Glucose: diabetes, steroid therapy, pancreatic disease, hypothalamic or adrenal disease
  2. Liver function tests: known liver disease; past h/o hepatitis, cancer
  3. Urinalysis: planned instrumentation of urinary tract
  1. Despite past concerns, a 1988 study found no association between wound infection and abnormal u/a in a series of TKR pts
  1. CXR: signs or sx of active chest disease; possibly, >70yo; intrathoracic procedures
  1. EKG:--Per 2002 ACC/AHA guidelines:
    1. “Class I” if sx suggest recent angina in a clinically intermediate- or high-risk pt scheduled for an intermediate- or high-risk procedure (click HERE for details on those criteria)
    2. “Class IIa” in an asymptomatic person with diabetes mellitus
    3. ”Class IIb” in pts with prior coronary revascularization; or (asymptomatic males > 45yo or asymptomatic female > 55yo) with > 1 CAD risk factor; or prior hosp. admission for cardiac causes
  1. The following ECG findings predict increased perioperative and long-term CV risk (2002 ACC/AHA guidelines):
    1. Left ventricular hypertrophy
    2. Horizontal or downsloping ST depression > 0.5mm
    3. Left bundle-branch block
  1. Echocardiography: In a prospective cohort study of 339 men, not more helpful than schemes below in predicting cardiac risk in non-cardiac surgery, even in pts with known CAD (Ann Int. Med 125:433, 1996-JW)

Sources include “2002 ACC/AHA guidelines”: Eagle KA, et al., ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery update: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). 2002. American College of Cardiology Web site)