CPR, PCA Flashcards
What is the equation for coronary perfusion pressure?
CPP = Aortic diastolic pressure - Right atrial diastolic pressure
How much time can be taken for inter-cycle rhythm checks?
2-5 seconds
What is the recommended tidal volume during CPR?
10 mL/kg
What are the two reasons to avoid hyperventilation during CPR
- increased intrathoracic pressure impeding venous return
- hypocapnia causing cerebral vasoconstriction»_space; decreased perfusion
What are the 3 phases of ischemia during ventricular fibrillation?
0-4 min: electrical phase - minimal ischemia, enough cellular energy stores available to maintain metabolic processes
4-10 min: circulatory phase - reversible ischemic injury - depletion of cellular ATP stores
>10 min: metabolic phase - potentially irreversible ischemic damage
After an unsuccessful attemp to defibrillate, how much should the joules dose be increased?
by 50% - do not increase subsequent doses
Describe how to perform open-chest CPR
- left-sided thoracotomy between 4th and 5th rub
- Finochietto retractors to open the chest
- consider removing the pericardium in any patient - but definitely indicated if pericardial disease present
- if one hand technique: right hand around left ventricule
- compress heart from apex to base to promote forward flow
How does CPR prognosis between dogs and cats compare?
Recent prospective observational study showed cats are almost 5 times as likely to survive to discharge compared to dogs
What is the recommended PaO2 and SpO2 target for PCA care?
PaO2 80-100 mm Hg
SpO2 94-98%
What are the MAP, ScvO2, lactate goals for PCA care?
80-120 mm Hg or higher
70% or more
less than 2.5 mmol/L
List 3 neuroprotective PCA care strategies
slow rewarming (0.25-0.5 C/hr)
seizure prophylaxis
osmotic therapy
What percentage of dogs and cats achieving ROSC die or are euthanzied before hospital discharge?
79%
What are the recommended PaCO2 targets for dogs and cats during PCA care?
dogs 32-43 mm Hg
cats 26-36 mm Hg
Why is the target MAP relatively high in PCA care?
because cerebral autoregulation may be absent
What is the recommendation for corticosteroid administration during PCA care?
- routine use not recommended
- consider low-dose hydrocortisone in patients with vasopressor-dependent shock after CPA
Describe the cerebral injuries sustained during CPA
after 4 min: cerebral ATP depletion - loss of cellular membrane potential and electrolyte pump activity
IC influx of Ca, Na, Cl
» cellular edema and membrane disruption
» cytosolic and mitochondiral Ca overload activates proteases»_space; cell damage
List the positive/beneficial effects of targeted temperature management in CPA care (7)
- mitochondrial protection
- decreased cerebral metabolism
- impediment of cellular Ca influx
- reduced neuronal excitotoxicity
- reduced ROS elaboration
- attenuated apoptosis
- conrol of seizure activity
What is the recommendation for targeted temperature management in the RECOVER guidelines?
2012:
* suggest cooling patients remaining comatose after ROSC to 32-34 C as quickly as possible
* maintain for 24-48 hours
Why is sedation crucial in targeted temperature management?
cooling may induce shivering»_space; increased O2 consumption, metabolic rate, RR, HR»_space; diminishes positive effects
Describe how length of CPA affects how ventilation affects brain perfusion
prolonged CPR - cerebral CO2 responsiveness is likely diminisedh for hours after - no cerebral vasoconstriction
more prominent in short CPR - as is more common in vet med
List reasons why microvascular blood flow may be impeded in PCA
No Reflow
microvascular obstruction or plugging from:
* endothelial cell activation and swelling
* neutrophil-endothelial cell interaction
* activation of coagulation and platelet aggregation
* pericapillary edema
* reduced deformability of PCA RBCs + tendency towards endothelial adhesion»_space; erythrocyte plugs
List possible indications for OCCPR
- failure of external/closed-chest CPR
- pleural space disease
- pericardia effusion/disease
- thoracic wall trauma
What coronary perfusion pressure cutoff has been associated with increased ROSC and survival to discharge?
15 mm Hg or greater
How do CPP compare between open-chest and closed chest CPR?
three times greater with open chest
Describe how to build a tourniquet for descending aorta occlusion
12-14 french red rubber catheter - cut into 3-4 cm long piece open on both ends
umbilical tape around descending aortia
mosquito hemostat pushed through the red rubber piece, then grasp both ends of the umbilical tape and pull throught the red rubber piece
push the red rubber piece down until the aorta is sufficiently clamped
hold umbilical tape ends in place behind the red rubber with the hemostat
What muscles have to be transected to perform a lateral thoracotomy approach for OCCPR?
- latissimus dorsi
- serratus ventralis
- scalenous
- pectoralis
- internal and external intercostal muscles
What scissors should be used for the lateral thoracotomy approach for OCCPR?
Metzenbaum
alternatively: scalpel blade
important: do not use these for opening the pleura, open pleura bluntly with hemostat
During OCCPR how do you perform a partial pericardiectomy?
- gasp and lift the perciardium with tissue forceps
- incise pericardium with metzenbaum ventral to the phrenic nerve - extend ventrally
After ROSC, how fast should aortic compression be released?
slowly over 10-15 min to minimize Ischemia-Reperfusion injury
What is REBOA?
resuscitative endovascular balloon occlusion of the aorta
Describe how you close the chest after OCCPR
- aseptically
- ideally by experienced surgeon or at least consulted by one
- pass absorbable monofilament (PDS) or wire around the ribs cranial and caudal to the thoracotomy site - avoid entrapment of the intercostal vessels
- tighten sutures with a square knot, at least 4 throws
- simple interrupted
optional: thoracotomy tube placement
What is the recommendation for antibiotic administration after OCCPR?
After ROSC: administer appropriate-spectrum IV abx
continue depending on patient status and contamination during thoracotomy
