Exam 1 - CPCR 2.0 Flashcards
T/F: currently, survival to discharge following cardiopulmonary arrest (CPA) in veterinary species is <6% if not associated with anesthesia; survival for anesthetic-related CPA approaches 50%
true
what is the most common underlying cause in veterinary medicine leading to CPA?
multi-organ dysfunction causing high vagal tone - leads to arrest
what is the most common etiology resulting in arrest? what are some other etiologies?
hypoxemia
anemia, arrhythmias, cerebral trauma, & anaphylaxis
what common signs are associated with arrest?
agonal breathing & apnea followed by collapse
why does respiratory arrest carry a better prognosis than cardiopulmonary arrest? which is more commonly encountered?
the heart continues beating for a short period of time following to the development of apnea
cardiopulmonary arrest is more common
what is the mechanism of cardiopulmonary arrest?
cessation of cardiac contractions
what is the most commonly encountered rhythm in patients with CPA?
asystole
what is asystole?
no electrical or mechanical activity of the heart
what is pulseless electrical activity?
occurs when there is still electrical activity in the heart but these impulses don’t stimulate contractions - complexes generated can appear as sinus beats or escape rhythms
when is ventricular fibrillation seen in veterinary patients?
rare - association with CPR, cardiac disease, or anesthesia
how can you differentiate between ventricular tachycardia & pulseless electrical activity?
if the heart rate is greater than 180 bpm - v tach
if the heart rate is less than 180 - PEA
what is the pathogenesis of CPA at 20 seconds, 5 minutes, & 30 minutes?
20 seconds - electrical activity within the brain is compromised due to lack of oxygen for high energy metabolism
5 minutes - complete depletion of ATP stores within the body
30 minutes - irreversible histological changes within cells are identified
what is phase I of ventricular fibrillation?
first 4 minutes - little to no ischemic damage to myocardial cells
why is phase I (electrical phase) of ventricular fibrillation most successful for defibrillation?
little to no ischemic damage to myocardial cells
what is phase II of ventricular fibrillation?
circulatory phase - next 6 minutes, reversible damage occurs within the cardiac myocytes
why is CPR recommended during phase II of ventricular fibrillation?
provide oxygen to the patient prior to defibrillation - if no CPR, patients suffer increased damage & are likely to fibrillate again even if successful the first time
what is phase III of ventricular fibrillation?
metabolic phase - fibrillation that has occurred greater than 10 minutes
irreversible ischemic damage to the myocardium & defibrillation is typically unsuccessful
the fundamentals of CPR focus on what 2 things?
improving perfusion to the heart & brain
identifying/addressing the underlying cause of the arrest
what is needed on a CPR team?
leader, compressors, ventilator, drug administrator, recorder/timer, & someone to obtain a history
what are the 2 most important pieces of equipment that should be immediately attached to a coding patient?
ECG & ETCO2
why is an ECG important for a coding patient?
essential for rhythm diagnosis between compressors & helps determine next therapeutic course of action
what therapy is indicated for non-shockable rhythms? what about shockable rhythms?
non-shockable: epinephrine & compressions
shockable: defibrillation & compressions
what are the non-shockable rhythms?
asystole & PEA
what ETCO2 measurement is considered to correlate with effective compressions? what if this isn’t achieved?
15 mmHg
efficiency of compressions should be evaluated for proper rate, depth, compression point, & posture
T/F: while not all patients will achieve an EtCO2 of >15 mmHg during CPR (which conveys a poor prognosis for recovery), every attempt should be made to ensure that this low value is not from inadequate compressions
true
how should compression be performed?
rate of 100-120 bpm, compressing the chest 1/3 to 1/2 of the total width allowing for complete recoil
what do incomplete or rapid compressions cause?
decreased ventricular filling & decreased cardiac output
T/F: efficacy of compressions decrease after 2 minutes regardless of perceived fatigue
true - switch every 2 minutes
optimal compressions generate approximately ___% of normal cardiac output when performed appropriately?
20%
where are compressions performed in small dogs & cats?
directly over the heart in line with the cardiac pump theory
what is the cardiac pump theory?
ventricles of the heart are compressed mimicking a contraction - compressions directly over the heart for small dogs/cats
where are compressions performed in large breed dogs?
compressions are performed at the highest point of the chest to increase intrathoracic pressure & causes the great vessels (vena cava & aorta) to collapse - thoracic pump theory
what is the thoracic pump theory?
compressions are performed at the highest point of the chest to increase intrathoracic pressure which causes the great vessels (vena cava & aorta) to collapse
recoil causes the vessels to expand again & triggers the movement of blood with the heart acting as a conduit for blood instead of the mechanism of movement
where are compressions performed in barrel-chested dogs (bulldogs)?
dorsal recumbency
what is the respiration rate used for CPR?
one breath every 10 seconds with an inspiratory time of 1 second & pressure of 10-15 cmH2O
how does hyperventilation negatively affect the coding patient?
it maintains positive intrathoracic pressures which compresses the major vessels impeding venous return
how does hypoventilation negatively affect the coding patient?
allows for the accumulation of carbon dioxide which results in cerebral vasodilation, increased intracranial pressure, and decreased cerebral perfusion
what kind of drug is epinephrine?
non-selective sympathomimetic - alpha & beta adrenergic stimulation
giving epinephrine results in what?
increased systemic vascular resistance, heart rate, & force of contraction
what is the primary purpose of giving epinephrine to a coding patient?
increase systemic vascular resistance to shunt blood back to the core organs
what is the recommended dose of epi given for the first two administrations given every other cycle?
0.01mg/kg
when is high dose epi used? why is it not the first choice?
when low dose epi has failed
it will achieve a higher ROSC, but is also associated with higher rates of neurologic impairment & mortality
what are your shockable rhythms?
pulseless ventricular tachycardia & ventricular fibrillation
what is the mechanism of vasopressin?
acts on V1 receptors in peripheral vasculature to increase systemic vascular resistance without increasing myocardial oxygen demand
what is the mechanism of action of atropine?
parasympatholytic - decreases vagal tone
what is the dose used for atropine for a coding patient?
0.04 mg/kg administered every other cycle opposite of epi - low dose epi -> 2 minutes later -> 1 dose atropine -> 2 minutes later -> low dose epi
what drugs can a patient receive through an ET tube? how does the dosing change?
epinephrine, atropine, vasopressin, lidocaine, & naloxone
double the doses - give through a red rubber as close to the carina as possible to improve absorption
T/F: asystole & PEA respond well to defibrillation
false
how is a defibrillator used?
patient in dorsal recumbency, paddles covered in electrode transducer gel, placed on lateral adjacent thoracic walls directly over the heart
no one in direct contact with table & patient after the paddles are in place, operator yells clear, everyone says clear back, patient is shocked
what is assessed after defibrillating your patient?
another round of compressions is performed & rhythm analysis performed at the next compressor change
T/F: in cases of shockable rhythms, epinephrine is typically not administered; instead defibrillation is performed every cycle that a shockable rhythm is diagnosed until the patient converts to a perfusing or non-shockable rhythm.
true
why should iv fluids only be given to hypovolemic patients as a part of CPR?
giving fluids to normovolemic/hypervolemic patients will increase right atrial pressure & decrease venous return
when is open chest CPR indicated?
pleural space/pericardial disease, thoracic trauma, giant breed dogs, concurrent surgery, & prolonged CPR (> 10 minutes)
why is open chest CPR not commonly performed?
significant morbidity and cost following this procedure with no change in survival to discharge
how is open chest CPR performed?
patient placed in lateral recumbency (left preferred) & 6th ICS is clipped/prepped while external compressions continue - sterile gloves are worn & chest cavity is entered & internal massage starts
in cases of open chest CPR for pericardial effusion, what should be done?
pericardium should be torn to allow the fluid to evacuate
how often should compressors switch in internal CPR?
every 2 minutes
