Perf Tech 3 Test 5 Flashcards

1
Q

Hemostasis

A

activation- clot formation- clot lysis

  • platetes form plug, CF reinforce platelets, fibrin acts as glue
  • clot strength; platelets 80-90%, fibrin 10-20%
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2
Q

Component Measurement Tests

A
  • PT/INR= extrinsic clotting factor (II, VII, X)
  • PTT= intrinsic clotting factors (II, IX, XI, XII)
  • fibrin concentration (doesn’t consider thrombin)
  • platelet count
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3
Q

Component Interaction Tests

A

TEG, ROTEM, Sonoclot

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4
Q

TEG

A

Thromboelastography (TEG)- whole blood hemostasis analyzer, point of care
-cup moves, pin stays still

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5
Q

TEG Parameters

A
  • R (enzymatic, CF, thrombin formation)- reaction time
  • alpha (fibrinogen)- speed of fibrin accumulation (speed as it gets stronger)
  • K (fibrinogen)- time until reaches fixed strength
  • MA (platelets)- ultimate strength of fibrin + platelets clot
  • LY30 (fibrinolysis) - rate of amplitude reduction 30 min after MA, indication of stability
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6
Q

TEG tracing abnormalities

A
  • elongated R= thrombin formation issue, too much hep or low CF= give protamine or FFP
  • low alpha angle= fibrinogen issue, low fibrinogen, thrombin, or platelet= give FFP or cryoprecipitate
  • low MA= platelet issue, low platelet count or fibrinogen= give platelets
  • high MA= hyperactive platelets= give anti platelet
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7
Q

TEG Assays

A

1) Standard= kaolin
2) Rapid TEG= tissue factor and kaolin= activates extrinsic/intrinsic pathways
3) Heparinase= runs one with heparin (normal) and one with heparinase which removes heparin
4) Platelet Mapping= tells you which pathway it inhibits
- -AA, arachidonic acid, aspirin
- -ADP, clopidogrel
- -GPIIb/IIIa inhibitor, abcixamab, tirofiban, eptifibatide

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8
Q

ROTEM

A
Rotational Elasometry (ROTEM)- cup stays still, pin turns 
-additional tests available
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9
Q

Sonoclot

A
  • viscoelastic detection system

- provides info on enter hemostatic process (with graft and numbers)

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10
Q

Kidneys arutoregulation pressures

A

80-160 mmHg MAP

  • so we loss this during bypass= less urine output
  • but low GFR doesn’t mean AKI
  • kidneys respond to decrease BF/volume
  • decrease urine due to pain, anxiety, nausea = increase ADH independent of BV
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11
Q

Ways to measure Kidney function

A

1) blood creatinine
2) creatinine clearance
3) blod urea nitrogen: creatinine ratio

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12
Q

Estimated GFR (eGFR) Formulas

A
  • better predictor of renal outcome
    1) Cockroft-Gault Formula= uses serum creatinine with creatinine clearance or GFR
    2) Modification of Diet in Renal Disease (MDRD)= 4 variables= serum creatinine, age, ethnicity, gender
    3) Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)= use cystatin C= which is only eliminated by glomerular filtration
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13
Q

Operative Renal Risk Factors on

A

so things on bypass that have risk for renal dysfunciton

  • low flow, CO, need IABP
  • bypass time >180 min, SIRS
  • hemodilution with HCT <21%
  • embolic events
  • –aoric atherosclerosis (9-17% will have dysfunction)
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14
Q

Pharmacological Intervention

A

Goal= prevent AKF that requires dialysis

1) dopamine low dose= renal dilation, lower Na reab
2) loop diuretics (furosemide)= block Cl,Na transport (lower O2 demand)
3) Osmotic Diuretics (mannitol)= flush out debris, ROS, increase renal flow. GIVE before ischemic insult
4) calcium channel antagonists
5) anti-inflmamatoy/antioxidant drugs

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15
Q

Operative Assessment of Renal Function

A

-low urine output = renal hypo perfusion (but doesn’t mean post op dysfunction)
-Oliguria- urine output less than .25-.33 ml/kg/hr
…..want to maintain proper perfusion

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16
Q

Neurologic Injury

A

decrease psychomotor speed, attention, concentration, learning, memory
-dysfunction present in 25-80% of patients

17
Q

Classification

A

1) Transient Ischemic Attack (TIA)- localized, rapid onset/recovery, no permanent damage
- causes= atherosclerosis, A-fib, thrombi, emboli, plaque
2) Reversible Ischemic neurologic Defect (RIND)- similar to TIA but 24-72 hours with full recovery
3) Lacunar Brain Infarct= specific cerebral artery occlusion, deep in brain, doesn’t resolve, aka stroke
4) Global Ischemia= long periods of hypo perfusion or massive emboli, poor recovery >50% die

18
Q

Pre-Op Risk Factors

A
  • AGE <60 yo 1% >70 yo 4-8%
  • ATHEROSCLEROSIS
  • HTN 55%, DM 25%= both change auto regulation, collateral BF and decrease ischemic tolerance
  • previous incident (13% of heart patients have TIA history)
  • carotid stenosis=
  • genetic APOE4, arrhythmias
19
Q

Surgical Stress that causes Brain Ischemia

A

1) Hypo perfusion= vascular disease, low MAP
2) emboli= on pump #1 cause brain injury during cardiac surgery, plaques, clots, GME, filling the heart
3) inflammation= due to impact vascular lining= thrombosis, tone, fluid transport, inflammation
- activates WBC/platelets
- 26-50% post op delirium

20
Q

Cerebral Metabolic Requirement for O2 (CMRO2)

A
  1. 3 ml/100 mg of brain tissue/min

- brain regulates BF by O2 demand

21
Q

Cerebral Blood Flow

A

55-60 ml/100g/min

-influenced by CMRO2, PaCO2, HCT, MAP

22
Q

Utilization of total resting O2

A

20%

  • also 20% of CO
  • brain weighs 1400g
23
Q

CBP and Cerebral Perfusion

A

1) Temperature- 10 degrees lower= 50% metabolic rate decrease

  • below 23 degrees, flow/metabolism disconnect
    2) MAP= autoregulation of CBF at 50-150 mmHg
    3) CO2= changes in PaCO2 change CBF independent of O2 demand = auto regulation with alpha stat
    4) HCT= hemodilution decreases viscosity/resistance and increase CBF
24
Q

Interventions to Decrease Neurological Morbidity

A
  • watch aorta, do carotid study, less aortic manipulation
  • flood chest with CO2, watch decannulation, use TEE
  • pharm to lower O2 demand (thiopental/propofol)
  • CO2 flush, filters, ACT
  • slow rewarm
  • alpha stat= preserves CBF auto regulation and decrease cerebral emboli