Post-op Complications Flashcards
What is the definition of an MI?
Rise and fall of troponin above 99th percentile plus one of the following: 1) symptoms 2) ECG evidence (st-t change, LBBB, new q waves) 3) imaging showing loss of viable myocardium or wall motion abnormality
What is the difference between a type 1 and 2 MI?
Type 1 - spontaneous due to an unstable coronary plaque
Type 2 - secondary to an extracardiac cause (demand ischemia)
What is the difference between STEMI and NSTEMI?
STEMI - major coronary territory or an area that has insufficient collaterals - requires urgent PCI.
NSTEMI - supplies smaller coronary territories or areas supplied by collaterals, PCI only if hemodynamically unstable or worsening symptoms
What percentage of vascular surgery patients have post-op MI (defined by elevated tropnonin?)
25%
What is unstable angina?
Recurrent or new typical chest pain with no evidence of serum troponin elevation (if trop elevated then its defined as an MI)
What are 3 types of heart failure?
1) Heart failured with reduced EF (systolic heart failure) - usually due to MI
2) Heart fialure with sustained EF (diastolic heart failure) - usually due to prolonged HTN and LVH
3) Right ventricular heart failure - usually due to LV failure and severe mitral valve disease or severe lung disease (cor pulmonale)
Which vascular procedure has the highest risk of cardiac morbidity?
Aortic surgery (EVAR 1%, Open 15%)
What is the cardiac event rate for lower extremity vascular surgery?
Depends on symptoms. CLI = 10% vs claudication 3%
What is the risk of periop cardiac morbidity after carotid surgery?
3% (1.5% with stenting)
What do pathologic q waves on an EKG represent?
Old MI, more leads = wider area of infarct
What does tall R waves and wide QRS complexes (with or without ST changes), and inverted T waves represent?
myocardial hypertrophy or dilation
What is the RCRI?
Revised cardiac risk index - 6 independent risk factors:
1-history of cardiac disease
2- history of chf
3- insulin therapy
4-chronic renal impairment
5-cerebrovascular disease
6-major surgery
According to the ACC/AHA, which patients should undergo noninvasive stress testing?
Patients with limited functional capacity < 4 METS (unable to climb 2 flights of stairs without chest pain or shortness of breath)
What did the CARP trial study?
The benefit of prophylactic PCI/CABG in patients with >70% coronary artery stenoses prior to surgery. There were no differences between patients who underwent coronary revasc compared with patients who did not.
What are 2 major limitations of the CARP trial?
1) Did not rigorously follow ACC/AHA screening and a minority of patients had evidence of severe ischemia on noninvasive testing - underpowered
2) Excluded patients wit left main disease (a population who may benefit from coronary revasc)
Should you give patients with CAD betablockade before periop?
No - POISE showed doubling of post-op strokes and cochrane review showed no clear evidence that periop prophylactic betablockade improved cardiac morbidity.
How long after PCI/stent should you delay elective non cardiac surgery?
30 days afer BMS and optimally 6 months after DES
How do you manage a suspected post-op NSTEMI?
1 - consult cardio
2- control heart rate and blood pressure with beta blockers/calcium channel blockers (if sbp > 100)
3- control pain to avoid tachycardia
4-treat tachyarrythmia (aflutter afib)
5- correct anemia, hypoxemia, follow trop
Name 5 common post-op respiratory complications
1-PE
2-pulmonary edema
3-aspiration pneumonia
4-pleural effusion
5-exacerbation of underlying disease
(ARDS, Bronchitis, resp failure, TRALI)
Name 5 patient related risk factors that put patients at higher risk of pulmonary complications
1-smoking
2-recent resp infection
3-OSA
4-COPD
5-CHF
(Functional dependence, age, ASA 2+, poorly controlled asthma)
Name 5 procedure-related risk factors for post-op pulmonary complications
1-longer than 2h
2-peri-op blood transfusion
3-type of anesthesia (local/general)
4-open surgery (over endo)
5-surgical site (aortic confers highest risk)
6- emergency surgery
Name 4 laboratory test risk factors for post-op pulmonary complications
1-anemia hgb < 100
2-spO2 < 90%
3-albumin < 35
4-BUN < 21
What percentage of anesthetized patients have atelectasis?
Up to 90%
What is the most common pathogen in ventilator associated pneumonia?
Staph aureus
What parameters are used in the clinical pulmonary infection score for ventilator associated pneumonia?
1 - temp
2 - WBC
3 - Sputum character
4 - CXR
5 - Culture of ET suction
6 - oxygenation (PaO2/FiO2)
What is the Berlin definition of ARDS?
1- Time: Within 1 week of known clinical insult/worsening resp symptoms
2 - CXR: bilateral opacities
3 - Edema cause: Not fully explained by cardiac/fluid overload
4- Oxygenation - need echo to exclude hydrostatic edema
What is cisatracurium used for with respect to resp failure?
Neuromuscular blockade - IV infusion for 48 h can help patients with ARDS and a PaO2:FiO2 less than 150.
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
Name the associated causes of renal failure
What is ischemic monomelic neuropathy?
A rare nerve injury following acute limb malperfusion, characterized by multiple distal axonal infarctoins resulting in motor and sensory mononeuropathies
List 4 common causes of unilateral neuropathy
- Entrapment
- Trauma
- Ischemia
- Vasculitis
List 7 common causes of bilateral neuropathy
- Metabolic (diabetes)
- Toxic (etoh, drugs)
- Vasculitis
- Vitamin deficiency
- HIV
- Monoclonal gammopathies
- Inflammatory or vasculitis
What are 3 first-line therapy of drug classes for treating neuropathic pain?
- tricyclic antidepressants: amytriptiline
- gabapentin: doesn’t work for everyone, takes weeks to take effect
- SSNRI duloxetine and venlafaxine
What is the rate of axonal regeneration?
1 mm per day
What are the 5 main terminal branches from the brachial plexus of the upper extremity
- musculocutaneous
- median
- ulnar
- axillary nerve
- radial
Which nerves are at risk during axillary dissections?
- musculocutaneous
- median
- ulnar
Which nerve do you have to watch out for in brachial dissections?
Median
Which nerve lies deep to the basilic vein?
Ulnar
What are the clinical findings of an axillary nerve injury?
Weak shoulder abduction and sensory deficit of deltoid
What are the findings associated with median nerve injury?
Sensory deficit on radial side of D1234. Weakness in thenar muscles.
What are the findings associated with an ulnar nerve injury?
Sensory numbness of 5th digit and weak abduction and adduction of fingers
What are clinical findings associated with femoral nerve injury?
Weakness or paralysis of quads, difficulty with knee extension, reduced patellar reflex, numbness along the course of the saphenous nerve on anteriomedial aspect of thigh
What are the phases of wound healing?
1 - inflammation
2 - prolipheration
3 - epithelialization
4 - remodelling
How can you prevent contrast induced nephropathy?
- Infusion of bicarb (better than saline in one RCT, NNT 8). Thought to alkalinze renal tubular fluid.
- Hold metformin 48 h before contrast and hold diauretics.
What is the definition of contrast induced nephropathy?
An 25% increase in creatinine within 3 days of contrast admin with no alternate cause
What are 4 risk factors for developing contrast induced nephropathy?
- Pre-existing renal failure (intra-arterial GFR < 60, IV GFR < 40)
- Diabetes
- Volume > 5 ml/kg
- Second contrast dose within 48 hours
