PREOPERATIVE EVALUATION:
NON-CARDIAC CONDITIONS

Chronic Pulmonary Disease
Chronic Renal Insufficiency
Diabetes Mellitus
Hematologic Diseases
Liver Disease
Bleeding Disorders
Chronic Corticosteroid Use
Hypertension
Alcoholism

I. Chronic Pulmonary Disease

1. FEV < 1 liter ass'd with inc. risk of complications
2. Highest rates of complications ass'd with upper abdominal or thoracic surgery
3. See "Respiratory risk in Non-cardiac Surgery" for information on predicting risk of perioperative respiratory failure
4. Smoking cessation > 8wks before surg. if helpful, < 8 wks may be ass'd with slightly higher complication rate
5. Pts with known asthma/COPD

1. Should be wheeze-free pre-op
2. Preoperative diagnostic studies to consider per 2002 ACC/AHA guidelines
   1. PFT's with spirometry, DLCO, response to bronchodilators
   2. ABG's to evaluate for COS retention
3. Maximize medical treatment
4. Chest physiotherapy most effective if begun preoperatively
5. Consider steroids before/after surgery

II. Chronic renal insufficiency

1. Perioperative risks associated with chronic renal disease:
   1. Risk of post-op acute renal failure is 50% if pre-op GFR is < 25cc/min
   2. "Chronic metabolic acidosis in patients with ESRD has not been associated with increased perioperative risk" (AFP 66:1471, 2002)
   3. Uremia can affect platelet function and increase risk of perioperative bleeding
   4. Severe anemia in CRI pts is ass'd with higher risk of intra-operative complications than absence of anemia (Am. J. Surg. 134:765, 1977 cited in op. cit.)
   5. CRI is ass'd with increase risk of cardiovascular events perioperatively, but "preoperative evaluation of the patient on dialysis or after renal transplantation should essentially be the same as for those patients without these conditions" per 2002 ACC/AHA guidelines
2. Special precautions to take perioperatively with CRI patients
   1. Preoperative labs:
      1. BUN, creatinine, lytes
      2. Hemoglobin and/or hematocrit
      3. Bleeding time or platelet function screening
      4. Consider ABG if HCO3- level is < 18mEq/L (AFP op. cit.)
   2. Correct hyperkalemia preoperatively if feasible (AFP op. cit.)
   3. Consider preoperative correction of CRI-associated anemia to HCT of 25% or so with erythropoietin (correct any existing Fe-deficiency concurrently with Epo) or RBC transfusion 
   4. Avoid hypovolemia to preserve existing renal function
   5. Interventions to minimize risk of abnormal bleeding from uremia
      1. Use caution with antiplatelets and other meds that may affect platelet function (diphenhydramine, NSAIDs, chlordiazepoxide, cimetidine)
      2. For ESRD pts, hemodialysis day before surgery (heparin-free if possible, otherwise wait 12h before surgery)
      3. Desmopressin IV preoperatively
      4. Cryoprecipitate preoperatively
      5. Estrogen IV or PO for 5d preoperatively
      6. RBC transfusion (if HCT > 30%, platelet function improves)
   6. Consider prophylactic preoperative antibiotics, esp. dialysis graft placement
   7. 50% of post-op ARF is non-oliguric, so follow Cr in these pts

III. Diabetes Mellitus

1. Perioperative problems:

1. Occult CAD (see above)
2. Autonomic neuropathy
3. Poor wound healing; may be more likely with poor glucose control per a retrospective study of 411 pts (Diab. Care 221:408, 1999--JW)

2. Pre-op goals:

1. Control blood glucose to <250
2. Ensure correct electrolytes and no acidemia
3. Screen for and treat asymptomatic bacteriuria
4. Cardiac evaluation (see above)

3. Perioperative management: Aggressive glycemic control probably best

1. Continuous IV insulin titrated to glucose < 200 mg/dL compared with intermittent SQ insulin was ass'd with sig. lower incidence of postoperative wound infection in (0.8% vs. 2.0%) a nonrandomized prospective study of 2,467 diabetic pts undergoing open heart surgery (Ann Thorac Surg. 1999;67:352-60--abst)
2. Stop oral agents the night before surgery (3d prior, if chlorpropamide); Stop metformin (few days?) before surgery
3. Can restart oral agent as soon as taking PO, but cover with SS regular for 3-4d, because of post-op catecholamine swings

4. Postoperative management

1. Avoid infection (minimize foleys, Ivs, etc)
2. Watch for silent MI

1. 50% of post-op MI's are silent, even more in DM
2. Check EKG post-op and days 3 and 5; peak incidence 3-5d post-op
3. Tele, serial enzymes probably aren't indicated

IV. Hematologic diseases

1. Anemia

1. May exacerbate myocardial ischemia; preoperative transfusion may be appropriate in pts with advanced CAD and/or CHF and substantial anemia (e.g. HCT < 28%) (2002 ACC/AHA guidelines)
2. If anemic, start w/u pre-op, though surgery can proceed unless severe

2. Polycythemia

1. At sea level, HCT >50% needs investigation
2. P. Vera carries risk of thrombotic events post-op; consider treating before surgery to lower this risk
3. Secondary polycythemia, on the other hand, less commonly associated with thrombosis

3. Thrombocytosis

1. Usually need platelet function studies to differentiate primary from secondary
2. Primary ass'd with incr. risk of hemorrhage & thrombosis; tx'd with chemotherpy or plateletpharesis
3. Secondary not ass'd with increased risks, so don't need to tx before surg

4. Thrombocytopenia

1. >50k adequate for most major surgery
2. >100k preferred for CNS, cardiac, eye, plastic surgery
3. Incr. risk at a given level if concomittant anemia or fever

V. Liver disease

1. Hepatitis

1. Asymptomatic chronic Hep B carrier: if nl transaminases and no inflammation on bx, no incr. surgical risk
2. Chronic persistent (elevated transaminases but nl albumin); surgery well tolerated
3. Chronic active: if symptomatic, avoid elective surgery
4. Alcoholic hepatitis: increased surgical mortality; if possible, abstain 6-12 wks before surgery to allow resolution

2. Cirrhosis: See also "Childs' Classification"

1. Delay surgery in Child's B or C until improvement occurs
2. If pt feels and looks ok and transaminases are <3x nl, ok for surgery
3. Perioperative management

1. Correct lytes
2. Address bleeding risk (see below)
3. Avoid rapid diuresis and watch for hepatorenal syndrome
4. Correct encephalopathy, if poss., before surgery
5. Watch for post-op encephalopathy from GI bleed, constipation, CNS depressants, uremia, sepsis, hypoxia
6. Watch for hypoglycemia from liver failure
7. Consider pre-op TPN
8. Consider pre-op prophylactic sclerotherapy of esophageal varices
9. Treat EtOH withdrawal early

VI. Bleeding disorders

1. Dialysis pts can have uremic platelet dysfunction; tx with dialysis, cryoprecipitate, or DDAVP
2. Pts with chronic liver disease have poor clotting from: decreased synthesis of coagulation factors, nutritional or malabsorptive vit K deficiency, thrombocytopenia from alcohol or hypersplenism. Check coag studies & platelet count before surgery
3. Pt on anticoagulation: course of action depends on indication

1. Strategies
   1. Stop Warfarin a few days before procedure and start adjusted-dose Heparin (IV or high-dose SQ) one INR becomes therapeutic
   2. Just reduce dose of or stop Warfarin a few days before the procedure; check to make sure INR is < 1.5 before operating
   3. Give low-dose vit. K 1-2d before the procedure; check to make sure INR is < 1.5 before operating
   4. Stop warfarin 5-6d before procedure and add enoxaparin 1mg/kg Q12h about 36h later; last dose of enoxaparin 12-18h before the procedure, restart afterward along with warfarin, stop enoxaparin once INR is therapeutic (This strategy tried in 20 pts on warfarin going for major surgery; no serious bleeding or thrombotic complications occurred--Am. J. Cardiol. 84:478, 1999--AFP)
   5. If emergent surgery, consider reversal of Warfarin with parenteral vitamin K or fresh frozen plasma
2. For Afib or post-MI: can safely d/c for several days
3. Hypercoagulable states: either operate at a low level of anticoagulation or correct them shortly before surgery and start IV heparin post-op
4. Prosthetic aortic valves: can d/c coumadin 3d pre-op; restart 3d post-op
5. Prosthetic mitral valves: change to IV heparin pre-op; d/c hep 6-12h pre-op; restart as soon as safe, then re-coumadinize

VII. Chronic Corticosteroid use

1. Supression of HPA axis occurs with use for 5-7d of equivalent of at least 20mg/d prednisone or daily use of more than 7.5mg/d prednisone
2. Since adrenal fn is the last part of the HPA axis to recover, nl cortrosyn stim test rules out suppression
3. "Stress dose" steroids

1. IV hydrocortisone 100mg Q8h starting pre-op and continuing post-op
2. Can taper by 50% after 2d, and by 50% the following day to maintenance levels until pt can resume their usual PO steroid
3. For minor procedures, can decrease to maintenance levels sooner
4. For arteriography or endosopy, one 100mg IV dose of hydrocortisone 1h pre-op should be sufficient

VIII. Hypertension--Discussed under Cardiac risk in Non-cardiac surgery

IX. Alcoholism

1. For patients whose EtOH intake is >4 drinks/d (these pts have RR of about 3 for morbidity during elective durgery), abstinence (with disulfiram) for 30d before elective surgery was ass'd with sig. lower risk of complications from surgery (31% vs. 73%) and nonsig. lower risk of major complications (13% vs. 42%) but similar mortality and length of stay in a randomized trial of 35 alcoholics w/no liver disease or other complications of EtOH use (BMJ 318:1311, 1999--JW)

(Sources include talk by Julie Magri, 1/96; see also: Cleveland Clinic Journal of Medicine 62:whole issue Nov-Dec, 1995; Mount Sinai Journal of Med. vol. 58 #1, Jan 1994-whole issue; Ann. Int. Med 98:504, 1983-original Goldman article; also “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)