anesthesia for vascular surgery
TRANSCRIPT
Anesthesia for Vascular Surgery
Neal BadnerAssociate Professor
Department of Anesthesiology & Perioperative Medicine
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Beta-blockers ACC/AHA Update
Fleisher LA et al, JACC 2006;47:2343-55 & Anesth Analg 2007;104:15-26.
-blocker study summary
Pts Author Outcome Details
Low risk POBBLELindenauer
Noneharm
927 pts, random663,635 data base
Intermediate risk
ManganoYang
DIPOM
POISE
? BenefitNonenone
dec MI, inc mort
200 no early496, blinded
921 diabetic pts
8,351 pts
High risk Poldermans
Lindenauer
Lower mortality
Lower mortality
112 pts, D-TTE
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
And then there was CARP
Variable Number (%)
Screened 5859
Angiogram 1230
Included 510
2 or more RCRI factors 250 (49)
Nuclear stress imaging 316 (62)
Moderate to large ischemia 226 (44)
Left main disease [excluded] [54]
Triple vessel disease 170 (33)
McFalls EO. NEJM 2004;351:2795-804
CARP – body count
Events re: vascular surgery Revascularize
(n= 258)
Proceed
(n=252)
Revascularized preop 240 (93%) 9 (4%)
CABG : PCI 99 : 141 N/A
Delay before surgery (days) 54 (28-80) 18 (7-42)
Preoperative mortality 10 (4) 1 (0)
Underwent vascular surgery 225 (87%) 237 (94%)
30 day mortality 7 (3%) 8 (3%)
30 day myocardial infarction 26 (12%) 34 (14%)
McFalls EO. NEJM 2004;351:2795-804
CARP – long term survival
McFalls EO. NEJM 2004;351:2795-804
More specifically, stents and vascular surg
Retrospective, database - Godet G. Anesthesiology 2005;102:739-46
Stents clot, so approach to PCI
Balloon angioplasty
Bare-metal stent
Drug-eluting stent
DelayWith ASA
14 days 30-45 days 365 days
Fleisher LA et al, Circulation 2007;116:1971-96
Can’t delay – bridging therapy:(a) ASA & clopidrogel periop(b) ASA & short-acting GIIb/IIIa(c) ASA & clopidrogel postop
Newsome et al, A & A 2008;107:570-90
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Vascular Anesthesia Goals
• Stable hemodynamics & preserve myocardial function
• Maintain O2 carrying capacity ie. Vol & Hct
• Protect renal function
• Maintain body temp
• Correct biochemical abnormalities that develop i.e., lytes, ph
Intraoperative Myocardial Ischemia
ECG Ischemia Detection
100
96
94
90
82
80
75
61
33
Sensitivity
II, V2 - V5
II, V4 & V5
V3, V4 & V5
V4 & V5
II & V4
II & V5
V5
V4
II
Lead
Effect of X-Clamp
Variable Supraceliac Suprarenal Infrarenal
MAP 54 5 2
PCWP 38 10 0
EF -38 -10 -3
% pts wall motion abN 92 33 0
% MI 8 0 0
% change in variable. From Roizen et al Vascular Sx 1994
Therapeutic Options
• Afterload reduction
1. Volatile - easy, fast
2. SNP - difficult (foil, pump), overshoot
• Preload reduction
1. GTN - myocardial benefit
2. Shunts and/or partial bypass
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Renal Protection
• Fluids• Mannitol• Dopamine• N-acetyl Cysteine (NACC)
Tang YI & Murray PT. Best Practices & Research Clin Anesth 2004;18:91-111.
Renal Protection (Fluids)
• Etiology of ARF 1. pre-renal azotemia2. ATN 20 (i) ischemia & (ii) nephrotoxins
• Kidneys receive 20 – 25% CO• Autoreg RBF & GFR @ MAP 85 – 180
MAP 60 –70 is on steep desc part curve Htn right shifts curve Lost in ATN
• no studies of extra fluid vs normal vasc• Supranormal CVT - dec C/O (ARF)
Shoemaker Chest 1988:94:1176-86.
Renal Protection (Mannitol)
• Conceptually inc tubular flow & “wash out” debris
• Na-K-Cl pump medullary O2 req• Free radical scavenger• Human studies
• No U/O @ 24 hrs• No CrCl @ 24 hrs
Zacharias et al, The Cochrane Library Issue 1, 2006
• Morbidity: high dose may cause ARF
Renal Protection (Dopamine)
• Low dose stim DA-1 & DA-2 rec • renal a. vasodilation RBF• Na reabsorp natriuesis
• Periop Studies• U/O @ 24 hrs by 0.33 ml/min
(95% CI 0.05 – 0.60)• No CrCl @ 24 hrs• No free H20 clearance
Zacharias et al, The Cochrane Library Issue 1, 2006
• Morbidity: tachyarrhythmias, ischemia, etc
Renal Protection (Fenoldopam)
• Pure DA-1 agonist not available in Can• In animals preserves RBF during
hypotension under GA• No effect contrast nephropathy with CRI
Stone et al JAMA 2003:290:2284-91.
• Maintained CrCl vs dec in control in infrarenal aortic Sx pts (n = 28) Halpenny et al EJA 2002;19:32-39.
Renal Protection (NACC)
• Antioxidant useful in acetaminophen toxicity
• Initial role in prevention of contrast nephropathy (not reproduced) Tepel M et al, NEJM 2000;343:180-4.
• No benefit in preventing ARF in infrarenal aortic Sx in pts with normal renal fx Hynninen MS et al, A &A 2006:102:1638-45.
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Spinal Cord Blood Supply
Longitudinal view – ant spinal a. NOT continuous
Spinal Cord Blood Supply (2)
3D Cross-sectional – location of feeder
Spinal Cord Blood Flow
Surgical exposure – feeder vessel
Spinal Cord Summary
• Low thoracic levels dependant on variable blood supply
• Anterior fibres more at risk than posterior
• May be source of significant back bleeding when aorta opened
Spinal Cord Protection
• Decrease X-clamp time
• Partial bypass
• Decrease spinal cord perfusion pressure (SCPP = MAP - SCP) using drain
X-Clamp & Outcome in TAA
Time (min) Pts % Paraplegia % ARF
0 - 15 8 0* 0
16 - 30 142 3.5* 4.2
31 - 45 90 10.0 7.8
46 - 60 16 12.5 6.3
> 60 4 25 0
Livesay et al, Ann Thorac Surg 1985;39:37-46. * p < 0.025 vs others
Neurologic Complications
Linear regression curves from Townsend: Sabiston Textbook of Surgery, 17th ed. 2004, Saunders
Partial Bypass
Vascular Anesthesia in Anesthesia ed Miller 6th edition 2005
Need: heparinization & CVT surgeon
CSF Drainage
Need: 1. drainage bag 2. pressure monitor
From animal studies
CSF Drainage - Background
Regression from Coselli et al. J Vasc Surg 2002;35;631-9
CSF Drainage & Paraplegia
CS Cina et al. J Vasc Surg 2004;40:36-44.
CSF Drainage
Indications:1. involvement T9-T12 (artery of Adamkiewicz)
2. Involvement of arch vessels (origin ant. spinal a.)
3. Previous TAA if AAA repair or vice versa
4. Symptomatic spinal ischemia
CSF Drainage
Complications:
n= 1486
Subdural hematoma = 2 with paraplegia
Meningitis (fatal) = 1
Cina CS et al. J Vasc Surg 2004;40:36-44
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Stent Procedures
Can also use tube grafts & fem-fem crossover
Endovascular Surgery
U.S. vascular procedures
Anderson et al. J Vasc Surg 2004;39:1200-8.
Endovascular Stents
Anatomic prerequisites:1. Aneurysm morphology
2. Distal access artery caliber
3. Proximal & distal landing zones – need 2 cm without major vessel
Submarine analogy
Unlike most procedures you will know of surgical C/O 1st
Surgical Complications
• Conversion to open 1 – 3%
• Endoleak 2 – 10 %
• Migration 1 – 5%
• Thrombosis 1 – 5%
• Rupture < 1 % at 5 yr
Stent Survival
Makaroun MS et al, J Vasc Surg 2005;41:1-9
Endovascular Surgery
Prospective, randomized though unblinded studyDavies MJ et al. Anaesth Intens Care 2002;30:66-70
OAR
N=50
EAR
N=50
General anesthesia 6 3
Combined general and epidural anesthesia 44 0
Combined spinal and epidural anesthesia 0 21
Epidural anesthesia 0 24
Spinal anesthesia 0 2
Pulmonary artery catheter 36 0
Central venous catheter 14 44
TABLE 2 – Anesthesia and Monitoring
Endovascular Surgery (2)
Davies MJ et al. Anaesth Intens Care 2002;30:66-70.
Endovascular Surgery (3)
Davies MJ et al. Anaesth Intens Care 2002;30:66-70.
Endovascular LHSC (1)
OAR EAR Significance O.R time (min.) 249 46 214 44 < 0.0001 General Anesthesia 99 85 (96) C.S.E. 0 4 (4)
0.0033
Epidural 89 1 (1) < 0.0001 Ephedrine (mg) 2.9 6.5 5.4 9.0 0.0253 Phenylephrine use (mcg) 125 271 110 200 ns Blood loss (ml) 1020 588 295 282 < 0.0001 pRBC transfused 29 3 (3) <0.0001 PAC Used 64 26 (29) <0.0001 CVP Used 99 88 (99) ns Crystalloid (ml) 3494 1308 2369 743 < 0.0001 Colloid (ml) 463 396 125 242 <0.0001 Values are mean SD or n (%) Nonrandomized, retrospective
Teague et al, CSA 2006;53:26210
Endovascular LHSC (2)
OAR EAR Significance Extubated post-op 89 84 (98) ns PACU hypotension 16 3 (3) 0.0037 PACU hypoxia 49 46 (52) ns Supp. O2 on D/C PACU 91 86 (97) ns ACS or MI 8 4 (4) ns CHF 24 0 <0.0001 Angina 6 8 (9) ns Dysrhythmia 8 3 (3) ns Hypotension 25 4 (4) <0.0001 Neurologic 8 6 (7) ns GI 11 1 (1) 0.0052 Pneumonia 10 2 (2) 0.0278 Values are mean ± SD or n (%) Values are mean SD or n (%) Teague et al, CSA 2006;53:26210
Endovascular LHSC (3)
OAR EAR Significance PACU duration (min) 210.9 ± 81.9 196.7 ± 69.7 ns Length of Hospital Stay (days) 12.9 38.3 5.7 4.8 ns Readmission within 30 days 4 4 (4) ns Death before discharge 5 1 (1) ns Death within 30 days 3 0 ns Values are mean SD or n (%) Values are mean SD or n (%) Teague et al, CSA 2006;53:26210
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management
Postop Epidural & Outcome
Study Comparison Result Weakness
Yeager ‘87 TEA vs prn Dec mortality (0 vs 4) & costs (50%)
Unblinded, mixed pts, high dose narc GA
Tuman ‘91 TEA vs prn Dec CVT C/O, vasc occlusion
Unblinded, ? Postop pain
Christopherson ‘93 TEA vs PCA Dec vasc occlusion Unblinded
Bois ’97 TEA vs PCA NS Unblinded
Norris ’01 GA ± TEA/PCA
RA ± TEA/PCA
NS underpowered
Park VA ’01 Epi vs PCA
(large)
Subgroup aortic Sx dec CV morbidity
Unblinded & uncontrolled
MASTER ’02
subgoup ’03
Epi vs PCA
(large)
NS
Aortic Sx dec resp C/O
Unblinded & uncontrolled
Postop Epidurals (2)
Beattie, Badner & Choi. A & A 93:853-8, 2001, Nishimori et al. The Cochrane Library Issue 3, 2006
Postop Epidurals (3)
Beattie, Badner & Choi. A & A 93:853-8, 2001,
Postop Epidurals (4)
• Cochrane Library – Aortic Surgery
• Randomized, controlled
• 13 studies, 1224 pts; 597 epi vs 627 sys
• Dec VAS pain scores
• Dec t IPPV (20%), CV C/Os, MI, GI C/Os, renal insuff
• No diff mortality
Nishimori M, Low JHS, Ballantyne JC The Cochrane Library, Issue 3, 2006
Seminar Outline
• Preop issues1. Beta-blockers2. Coronary stents
• Intraop management1. Crossclamp pathophysiology2. Renal Protection3. Spinal Cord Protection 4. Endovascular Approach
• Postop1. Pain Management