Pre-op Assessment Flashcards
1
Q
Why do we “preop” a patient?
A
Minimize peri-operative mortality and morbidity
Minimize surgical delays
Determine post-op disposition
Evaluate patient’s health
Formulate anesthetic plan
Communicate issues among providers
*Gov’t over site requires a pre-anesthesia eval w/in 48 hrs of scheduled surgery
2
Q
Coronary risk factors
A
Smoking HTN DBM HLD Family hx Socioeconomic status (access to care)
3
Q
Comorbidites related to cardiothoracic surgery include:
A
Respiratory Neurological PVD Renal Thyroid Peptic ulcer disease Past cardiac surgery
4
Q
Why is knowing about past cardiac surgery important?
A
Re-do procedures associated with higer blood loss and morbidity
5
Q
Dental hygiene is important for what type of cardiac disease?
A
Valvular disease
6
Q
Criteria for low risk procedures
A
Low chance of: bleeding long surgery time unlikely to cause surgical stress <1% MACE
7
Q
Criteria for high risk procedures
A
High CV morbidity
Longer hospital stays
Higher risk of bleeding
>1% MACE
8
Q
Major Patient-related risk factors
A
Unstable angina Recent MI (<6 weeks) Malignant arrhythmias -SVT -2 or 3 degree AV blocks -Symptomatic bradycardia -VT
9
Q
Intermediate Patient related risk factors
A
Established CAD Previous MI btwn 6 weeks-3 months prior to surgery Stable angina CHF with EF of < 35% DBM CKD with creat >2.0 CVA
10
Q
Minor Patient Related risk factors
A
Previous CABG more than 6 years before
Myocardial revascularization > 3 months negative stress test within the past 2 years
HTN
>70 years of age
11
Q
AHA recommendations for elective noncardiac surgery following Acute Coronary Syndrome
A
60 days
12
Q
What is one of the biggest indicators for post op major adverse cardiac complications?
A
Heart failure with EF < 30%
13
Q
AHA recommendations for pt with known valvular disease?
A
Echo w/in 1 year of surgery
14
Q
PHTN
A
High risk complications
Prevent hypoxia and hypercarbia to help with complications
15
Q
Perioperative myocardial inury (2 stages)
A
Stunning (temporary)
MI (cell death)
16
Q
Determinants of perioperative myocardial injury
A
Disruption of blood flow
Re perfusion of ischemic myocardium
Adverse effects from bypass (inflammatory cascade and immune system activation)
17
Q
Morbidity and mortality rate of pts with periopertive MI
A
49% (vs 4% of those that do not)
18
Q
What is time limit of ischemia before necrosis occurs?
A
20 minutes
19
Q
What is the wavefront phenomena?
A
necrosis starts in the subendocardial region and progresses to the subepicardial region
20
Q
What is the primary trigger for apoptosis
A
Acidosis
21
Q
MI diagnosis
A
1 biomarker in 99th percentile and any of these symptoms:
ECG changes
Echo with RWMA
Patient symptoms
22
Q
MI biomarkers
A
Myoglobin CK CK-MB Troponin LDH
23
Q
Peroperative MI definition in CABG
A
elevation of more than 10x the 99th percentile of normal
24
Q
Which biomarkers show immediately with MI?
A
None
25
Order biomarkers occur
```
Myoglobin - peaks at 4 hours
CK - peaks at 16 hours
CK-MB - 24 hours
Troponins - 24 hours
Lactate - 72 hours
```
26
What is the most reliable assessment of contractile dysfunction?
TEE - RWMA can occur w/in 10-15 sec of ischemia onset
27
ECG changes with MY
new Q waves of 0.03 sec
new QRS deflections
ST changes not reliable in OR because of body placement and lead placement, hypothermia, electrolyte imbalances
28
Parsonnet Index
Risk model derived from 3500 operations to provide approximation of risk based on 47 factors
29
STS National Adult Cardiac Surgery Database
largest database for nwer risk-adjusted scoring system
100K pts analyzed
30 risk factors
Highest mortality rates seen in renal failure, emergent status, multiple reoperations, and NYHA class IV status
30
EurosCORE II
20K pts
Most widely used model and current standard for cardiac surgical risk
identifies multiple high risk pt comorbidities - pts are low, med, high risk
OK to assess pt for CABG and valve surgeries, but not combined
31
Consistent risk factors for cardiac surgery
```
Every 5 years over age 60
Female
EF < 30%
Obese
Reoperation
Type of surgery
Emergent surgery
```
32
METs
Excellent >10
Good 7-10
Moderate 4-6
Poor < 4
33
Examples of 4 METs
walking up hill, running short distance
walk 4 city blocks
heavy work around house
34
1 MET is equal to
basal metabolic rate - 3.5 mL O2/kg/min
35
Non-Cardiac surgery risk tools
RCRI - evaluates 6 factors but is not surgery specific
ACS-NSQIP - surgery specific risk; preferred tool
Gupta- includes medical therapies
36
T or F: High risk pts undergoing low risk procedures require ECG
False. Routine ECGs in asymptomatic patients is not useful. However, if surgery is not low-risk, ECG is warranted
37
T or F: Lab markers for MI are are recommended for pts at high risk of complications that may benefit from an intervention
True
38
T or F: Beta Blockers should be continued in non-cardiac surgery pts who have been taking these meds
True. Avoids acute withdrawl
39
T or F: Beta Blockers should be started within 1 day of non-cardiac surgery
False. Increased risk of hypotension, stroke, and death. UNLESS pt at high risk fro MI
40
T or F: Statins should be continued perioperatively
True. Pts having vascular surgery should have statin treatment initiated.
41
T or F: Alpha 2 agonists should be initiated before noncardiac surgery
False. Increased risk of cardiac arrest, hypotension, AKI.
42
T or F: Aspirin therapy in pts w/o stents is not recommended
True. Unless pt risk of MI is higher than surgical bleeding
43
T or F: RBC transfusion increases O2 carrying capacity of the blood
False. 2,3-DPG and ATP must normalize. Recommend restrict transfusion < 7 g/dL in asymptomatic, hemodynamically stable pts without CAD. In pts with CAD, number is < 8 g/dL unless symptomatic
44
Standard of care after stent placement is:
Dual anti platelet therapy wit aspirin and a P2Y12 platelet inhibitor. Continued for 6 weeks for bare metal; 1 year for DES.
45
If pt has angioplasty with no stents, how long should wait before having elective surgery?
2 weeks
46
IF pt having acute coronary syndrome should wait how long before elective noncardiac surgery?
60 days
47
How long after DES should pt wait for elective surgery?
6 months
48
T or F: Evidence is against using preoperative elective PCI to reduce risk of surgery
T. If noncardiac surgery is performed w/in 4 weeks of PCI, 10% chance of cardiac event
49
BMS - endothelial stent coverage is complete by when? What is the significance?
12 weeks; risk of re-stenosis drops. IF noncardiac surgery w/in 6 weeks of BMS, risk of cardiac complications is 30%
50
DES
perform better than BMS for 1st year, but similar after. Cause less long-term inflammation.
51
What three physiologic responses occur after balloon angioplasty?
1. Immediate arterial wall recoil w/in 24 hours
2. Negative arterial remodeling
3. Neointimal hyperplasia response of smooth muscle proliferation and migration
52
Stent Restenosis peaks when?
4-12 months
| When vessel is 50% with symptoms or 70% total, intervention needed
53
Stent thrombosis
Occurs w/in 30 days. High risk pts have 2.5% chance
54
What is the most widely used cardiac diagnostic tool
Echo. LV EF, RWMA, Valvular disease
55
4 classifications of assessing RWMA during echo (LV)
1. Normal
2. Hypokinetic
3. Akinetic
4. Dyskinetic/anuerysmal
56
RV diastolic function can be assessed how during an echo?
IVC. If collapses by 50% on inspiration, RA pressures are normal (<5 mmHg)
57
Normal Mitral Valve
4-6 cm2
58
Mitral valve stenosis
Mild - >1.5 cm2
Mod 1-1.5 cm2
Severe - 1cm2
59
What is important to remember in pts with MS?
Preload
60
Mitral valve regurg
```
Common with LV dysfunciton
Independent predictor of morbidity and mortality
Mild - <30%
Mod 30-49%
Severe - >50%
```
61
Normal aortic valve
2.6-3.5 cm2
62
Aortic stenosis
Mild - >1.5 cm2
Mod - 1-1.5 cm2
Severe < 1 cm2
63
Concerns with AS
LVEDP increases - causing LV hypertrophy. Filling becomes dependent on LA contraction, leading to afib. In severe cases, LV systolic function declines
64
Recommendations fro symptomatic hemodynamically significant AS prior to elective noncardiac surgery
AVR
65
Aortic regurg
Mild - <30%
Mod - 30-49%
Severe - >50%
66
Which has higher mortality rate? AR or AS?
AR
67
Tricuspid regurg
Tricuspid annulus > 4 cm needs surgical correction
68
Tricuspid stenosis
very rare
69
Pulmonary Valve regurg
Very rare. PHTN
70
Pulmonary valve stenosis
Usually congenital. Not well seen on Echo.
71
Prosthetic valves
Difficult to assess on echo due to acoustic shadows
72
Stress echo
Pt on treadmill or bike
12 lead ECG and BP
Ischemia dx with ST segment depression > 1 mm, fall in BP, or CP
Limited if pt on BB
73
Pharmacologic stress test
Pt receives chronotropic/inotropic agent - dobutamine or a vasoldilator like adenosine. Atropine can increase sensitivity of the test
74
Formula - cardiac output
CO = HR x SV
75
Formula - SVR
[(MAP - RAP)/systemic blood flow ] x 80
76
Myocardial Nuclear Scintigraphy
Most common dx tool to evaluate for MI in preop assessment. Performs better than exercise stress test.
CT or PET scan
Radioactive substance is injected and machine picks up the decay around the heart. Areas of scarring won't have decay.
Mod to large areas of ischemia is associated with high sensitivity for risk of perioperative MI and death. A normal study has a very high negative predictive value
77
CCT/Cardiac Computed Tomography
256-320 slices of heart
Ionizing radiation is used
Pts HR slowed to 60 bpm with BB to allow for imaging
94% dx of CAD and 99% negative predictive value
*Note. Only validated in pts with no known CAD
Gold standard for evaluating aorta
78
Cardiac MRI
Function, flow, morphology, tissue eval, perfusion, angiography, metabolic studies of cardiac structures w/o radiation
Gold standard for BiVentricultar volumes, EF, and mass. Also gold standard for myocardial scarring eval, RV eval, and chronic thoracic aneurysm
Negative predicitve value for 3 yr cardiac events is 99%.
79
Carotid artery stenosis
Major cause of stroke
Bruits on physical exam
US is performed first with CT or MRA performed if needed
Carotid exams should be done if pt has a bruit, hx of CVA, or PVD
80
Renal artery stenosis
Cause of secondary htn
| US performed initiially
81
Coronary Angiography
Gol standard for coronary anatomy and severity of CAD
Indications: >40 in men, post menopause women, symptoms, LV dysfunction, CV risk factors
PCI has 99% success rate
Must be < 1 yr for pts undergoing CABG
ECG, coag studies H & H, GFR
Must have 5 lead ECG
82
Contrast dye precautions
Allergies
Anticoagulant and antiplatelet effects
Induce transient HB, QT prolongation, hypotension
Nephropathy - esp pts with DBM, CKD, HF
Avoid hypotension, NSAIDS, provide hydration
Max dose for healthy kidneys is 4 mL/kg
83
Dx of contrast induced nephropathy
Creat elevation > 0.5 mg/dl or 25% in 48 hours
| Creat levels of 1/5 mg/dL or GFR < 60 mL/min red flag
84
Right side Cath complications
RBBB, Complete HB, Valvular damage, perforation, paradoxical air embolus
85
Left side cath complications
MI, VF, VT, stroke, thrombus
86
EP lab - ablation
Catheter in femoral vessels; systemic heparinization required
Mapping areas of arrhythmia
Scar tissue created
Can be long procedures
87
EP lab - cardioversion
Want to slow accessory pathways - not AV node - avoid BB, verapamil, digoxin. Do use amiodarone, procainamide.
Opioids have no effect on conduction system. Volatile agents depress AV node but also depress accessory pathway conduction so ok to use.
Paralytics that have cholinergic effects (Succ, pancuronium) avoided
Avoid sympathetic stimualtion
88
Postop care Handoff
```
What procedure performed
TEE results
Ease of transitioning from bypass
What inotropic support needed
Prescribed hemodynamic parameters
```
89
Tamponade
hypotension, raised CVP, pulses paradoxus, ECG dampening
90
Arrhythmias post op
Common
Check electrolytes - K and Mg common causes
Brady most common after valve surgery
Afib most common overall - 90% of pts that were in SR before will return
91
Complications after cardiac surgery
1. Device related infections (IEDs, LVAD) - mortality up to 35%
2. Sternal wound infections - 7% mortality rate
3. Endocarditis - prosthetic valve
