Preop
preop assessment
determine presence of risk factors
evaluate MET (2-3 flights of stairs= good cardiac reserve/exercise tolerance)
co-existing non-cardiac disease (DM, HTN)
physcial exam
specialized testing - exercise ECG, stress echocardiography , nuclear stress test, cardiac Cath
desired MET for patients
>4 MET
active cardiac conditions (6)
unstable coronary syndromes
acute (MI<7 days) or recent (>7 days but < 1 month ago) with evidence of important ischemic risk
*>60 days post MI ideal
unstable or severe angina until elvaulated
decompensated HF
severe valvular disease (severe AS or MS)
Significant dysrhytmmias (severe AV block, type II, 3rd degree, SVT anf VT)
age (considred when associated with fratility)
goals
prevent myocardial ischemia by optimizing O2 supply and reducing O2 demand
monitor for ischemia
treat ischemia
IV lidocaine, esmolol. fent, remi, dex to blunt HR
DL < 15 seconds
succinycholine, vec, roc, cisatracurium
*avoid histamine release and decrease BP (atacurium)
medication assessment
minimize O2 demand
BB- continue *give glycopyrrolate, atropine, or isoproterenol
alpha 2 agonists - decrease SNS outflow (BP/HR)
ACE-I - D/C 24 hours prior to surgery *sympathomimetics for Hypotension
statins
DAPT - bridge but default to expert
control hyperglycemia < 180 mg/dL
neuraxial not recommended due to bleeding
what is a MET
assesses cardiopulmonary fitness & estimates risk for major postop M&M
determines if further testing is needed
metabolic equivalent of task
rate of energy consumption at rest
1 MET = 3.5 mL/kg/min
cancellectomy recommendations (3)
revascularization by cardiac surgery
revascularization by PCI
optimal medical management
prevent
persistent tachycardia
systolic HTN
SNS stimulation
arterial hypoxemia
Hypotension
volatiles or no
*only downside is they decrease BP and associated with reduction in coronary perfusion pressure
perioperative MI causes
neuroendocrine stress response
*increased HR/BO, metabolic changes -> increased O2 demand -> MI
prevention: BB and insulin and normothermia
inflammatory response
* hypercoagulable state, plaque rupture -> thrombus -> decreased O2 delivery
prevention: statins, antiplatelets
* decreased hematocrit/hypoxia -> decreased O2 delivery
prevention: transfusion, O2
* decreased BP vasconstriction -> decreased O2 delivery
prevention: prevent hypotension, nitro
define emergent surgery
loss of life or limb if surgery not within 6 hrs or less
* proceed irerctly to emergent surgery without pre-op cardiac assessment
focus on survillence (serial cardiac enzymes, hemodynamic monitoring, serial ECGs) and early treatment of post op CV complications
decreased O2 delivery
decreased coronary blood flow
tachycardia
hypotension
hypocapnia
coronary artery spasm
decreased O2 content
anemia
arterial hypoxemia
shift oxyhemoglobin curve to the left
maintain vitals where
within 20% of normal awake baseline
opioids
risk stratification
RCRI - revised cardiac risk index
* high risk procedure
*history of IHD
*history of HF
*history of TIA/CVA
*DM with insulin
*serum creatinine > 2 mg/dL
0 = 0.4%
1= 1.0% (low risk)
2= 2.4 % (elevated risk)
3+ = 5.4% (elevated risk)
urgent surgey
life or limb would be threatened if surgey does not proceed within 6-24 hours
increased o2 requirements
SNS
tachycardia
hypertension
increased myocardial contractility
increased afterload/preload
perioperative MI is closely assocaited with
HR in vascular surgery
*increased HR increases myocardial O2 requirement and decreases diastolic time for coronary blood flow - therefore O2 delivery
neuraxial
ehh, decreased in BP assocaited with epidural/spinal must be controlled
prompt treatment of HypoTN that exceeds 20% pre block BP is necessary
calculate the RCRI for a patient
57M, scheduled exploratory lap
PMHX of Paraxosymal Afib, CVA (2023), DM,
med list: metformin, isosorbide dinitrate,
3 = 5.4%
*major abdominal surgery, CVA, nitrate therapy
time sensitive surgey
delays exceeding 1-6 weeks woudl adversely affect patient outcomes
cardiac risk assessment algorithm
1. emergency surgery -> proceed
2. active cardiac conditions -> postpone until condition is evalulated
3. estimate risk of perioperative death (RCRI) -> proceed if less than 1%
4. assess functional capacity -> >4 MET proceed
5. assess whether further testing will impact care
6. proceed to surgery or alternetive therapy
why do you want to avoid hyperventilation
hyocapnia may cause coronary artery vasoconstriction
tachycardia
bradycardia
hypotension
tachy- esmolol
Brady - glycropyrolate > atropine
Hypotension- fluid bolus, sympathomimetic drugs (ephedrine, phenylephrine)