Vascular Surgery Reducing Morbidity Dr. Peters

Reducing the Morbidity of Major Vascular Surgery David C. Peters MAJ, MC Goal: Perioperative Physician   Knowledgeable Consultant Indispensable Major Sources of M&M  Cardiac – – – Ischemia / Infarction Arrhythmias CHF Major Sources of M&M HTN / Hypotension  Cerebral Vascular Insult  Renal Impairment  Graft Thrombosis  Which patients are at risk for Morbidity? Reducing Morbidity: Decrease Cardiac Ischemia Ischemia occurs most often in the postoperative period as stress alters the O2 supply-demand. Anesth 72:153, 1990. Post-Surgical Stress  Increased catecholamines (2-3x nl) – – – Elevated NE results in coronary vasoconstriction Increased PLT aggregation and thrombosis Tachycardia JAMA 261:3577, 1989. Stress Induced Ischemia  Long duration ischemia resulted in a 32x increased risk of cardiac complications. – – ICU admission proven benefit Holter monitoring not sufficient Anesth 62:107,1985. Anemia’s Role in Morbidity  Abnl state of extraction (?) CaO2=(1.34 x HgB x Sat) + (.003 x PaO2)  Anemia (cont’d) 27 Elective Infrarenal Vasc. Procedures: – 10/13 HCT<28, ischemic ECG 6 suffered morbid cardiac event – 2/14 HCT>28, ischemic ECG no morbid cardiac events Crit Care Med 21:860,1993. Avoiding Cardiac Events: Use of PA catheter.  Rao’s Goal: Maintain hemodynamic parameters within 10% of baseline values in 733 pts with a h/o MI. Anesth 59:499,1983. Avoiding Cardiac Events: Rao (cont.) Days Monitored 1 3-4 Events 8/210 6/439 % 3.8% 1.4% *p<0.05 Anesth 59:499,1983. Avoiding Cardiac Events: Epidurals Epidural MSO4: 1. Decreased [NE] at 6 and 24 hr compared to IV. 2. Decreased incidence of hypertension. JAMA 261:3577,1989. Avoiding Cardiac Events: Epidurals (cont.) Fent/Bup following LE vasc surg: 1. Decreased hypercoag. state by TEG. 2. Decreased thrombotic complications. 3. Trend toward decreased risk of MI Anes Anal 73:696,1991. Beta-1 Blockade... Where the Money is! B-adrenergic Blockade Good: 1. Decrease in HR 2. Decrease in contractility 3. Decrease in myocardial O2 consumption B-adrenergic Blockade Bad: 1. Decrease in CO 2. Side-effects due to non-selectivity 3. Intracardiac conduction delay B-adrenergic Blockade Two studies; single dose pre-operative B-blocker: 1. 12x reduction in the incidence of intra-op ischemia (no infarctions). 2. Sig. decrease # and duration of intra-op ischemic episodes. Anesth 68:495,1988. Am J Surg 158:113,1989. B-blockade- study design: Randomized, double-blind, placebo controlled Pre-op: atenolol/placebo Immed. Post-op: atenolol/placebo Daily until d/c: atenolol/placebo NEJM 1996;335:1713. B-blockade... study specifics: 200 patients enrolled - Atenolol arm 99 - Placebo arm 101 194 survived to be discharged 192 followed for 2yrs Beta Blockade- cont: Lg, multi-center study  Pt’s with cardiac risk factors + abnl dobutamine echo  Placebo vs Bisoprolol  N Eng J Med 1999;341:1789-94. Placebo vs. Bisoprolol How Does B-Blockade Work?  Decreased stress response? – NO- epi, NE, cortisol, ACTH lvls unchanged  Etiology unclear – – – improved hemodynamic stability less narcotic requirement with improved pain scores less cardiac troponin release (NS?) Anes 1999;91:1674-86. Summary M&M more common in pt’s with DM  ICU admission is a proven benefit  Anemia is bad  PA cath- possible benefit  CVP- no benefit  Summary Epidurals- decreased incidence of some complications  Beta blockade!!! 