Chapter 3- Cardiopulmonary Resuscitation Flashcards
RECOVER
Reassessment Campaign on Veterinary Resuscitation Initiative
1) Preparedness and prevention
2) Basic life support
3) Advanced live support
4) Monitoring
5) Post- Cardiac Arrest Care
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What is the rational behind starting CPR immediately (after no more than a 10-15 second ABC assessment) rather then pursuing further diagnostics (such as pulse palpation)?
1) Pulse palpation is insensative test for CPA in humans and may also be insensative in dogs/cats
2) Even short delays in starting CPR in a pulseless patient reduces survival rates
3) Starting CPR on a patient not iin CPA carries minimal risk
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Basic Life Support consists of what and why?
Chest compressions to restore blood flow to tissues and pulmonary ciruculation
Ventilation to provide oxygenation of the arterial blood and remove carbon dioxide from venous blood
There is a higher percentage of primary respiratory arrest in dogs and cats than in people (vs cardiac >respriatory in humans)
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Chest compressions goals
- Provide blood flow to tissues, decreaase ischemic injury and blunt reperfusion injury
a) restore pulmonary CO2 elimination and oxygen uptake by providing pulmonary blood flow
b) delivery of oxygen to tissues to resore organ function/metabolism - Excellent compressions are only 30% of normal cardiac output
- Compress 1/3-1/2 width at rate 100-120/min x 2min cycle
- Thoracic elastic properties
1) allow the chest to recoil between compressions, creating subatmospheric pressure = draws blood into the ventricles
VS
2) increased intrathoracic pressure during chest compression forcing blood from the thorax into systemic circulation
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Myocardial Perfusion Pressure (MPP)
- Majority of myocardia perfusion during CPR is during decompression phase of chest compressions
- MPP AKA CPP or coronary perfusion pressure = arterial diastolic pressure - right atrial diastolic pressure.
- Higher MPP during CPR is associated with inceased success (marker of CPR quality)
- Myocardial blood flow will decrease at compression rates greater than 120bpm
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Ventilation (airway and breathing)
- Do not stop chest compressions to intubate
- 10 breaths/min,
1) becase hyperventilation or low arterial CO2 causes cerebral vasoconstriction leading to decreased cerebral blood flow and oxygen deliver
2) increased intrathoracic pressure cuased by PPV will impeed venous return to chest reducing effectiveness of chest compressions and reducing MPP - Compressions and mouth-to-snout breath ratio is 30:2
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Monitoring CPR
- EKG and Capnography!
- EKG evalutaed q2 minutes
- Most common arrest rhythms in dogs and cats
1) Asystole
2) PEA- pulseless electrical activity
3) VF-Ventricular fibrillation - Detection of measurable ETCO2 suggests correct ET placement
- Return of ETCO2 corresponds with ROSC
- ETCO2 is proportional to pulmonary blood flow and can be used as an indicator of chest compression efficacy (<10-15mmHg is a low value during CPR and ulikely to be associated with ROSC)
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Advanced Life Support
Drugs (IV or IO):
1) Vasopressors
2) Parasympatholytics
3) Antiarrythmic drugs
4) Reversal agents
5) IV fluids
6) Corticosteroids
7) Alkalinizing agent
Defibrillation to treat:
1) Ventricular fibrillation
2) Pulseless ventricular tachycardia (VT)
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Vasopressors
- becuase CO is ~30% of normal or less
- Increase the SVR to redirect bloodflow from periphery
- Epinephrine (0.01mg/kg) a catecholamine causes peripheral vasoconstricion via alpha-1 receptors (but also acts on beta 1 and 2)
- Low dose (0.01mg/kg) recommended early in CPR (can do high dose (0.1mg/kg) late in CPR)
- Mainstay of treatment for asystole and PEA
- Vasopressin (0.8U/kg) is an alternative to epinephrine (interchangably or in combination with epi) with the advantage that it works in an acid environment (where alpha 1 receptors may become unresponsive) and it lacks inotropic and chronotropic effects (via Beta 1 receptor) which may worsen myocardia ischemia if patient acheives ROSC
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Parasympatholytics
- Atropine (0.04mg/kg)
- Useful in asystole and PEA (especially if associated with increaed vagal tone)
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Antiarrhythmic drugs
- VF refractory to defibrillation may benifit from amiodarone
- Amiodarone (2.5-5mg/kg) has been reported to cause anaphylactic reactions in dogs
- Lidocaine (2mg/kg slow push) is a less effective alternative to amiodarone for patients with refractory VF
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Reversal Agents
- Naloxone for opioids (0.04mg/kg)
- Flumazenil for benzodiazepines (0.01mg/kg)
- Atimpamezole (0.05mg/kg) or yohimbine (0.11mg/kg) for alpha 2 agonsits
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IV fluids
-maybe harmful to a euhydrated or hypervolemic patient because it an increase CVP rather than arterial blood pressure (so a right atrial increase in pressure, which will decrease MPP and cerebral perfusion pressure)
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Corticosteroids
Routine use of corticosteroids is not recommended during CPR
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Alkalinizing agents
- Severe metabolic acidosis can develope with prolonged CPA (>10-15 minutes)
- Leads to inhibition of normal enzymatic activity and metabolic activity and severe vasolidation
- Sodium bicarbonate (1mEq/kg, once, diluted)
- Reserved for patients with severe acidosis <7.0 of metabolic origin
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