CPR, PCA

Question 1

What is the equation for coronary perfusion pressure?

Answer 1

CPP = Aortic diastolic pressure - Right atrial diastolic pressure

Question 2

How much time can be taken for inter-cycle rhythm checks?

Answer 2

2-5 seconds

Question 3

What is the recommended tidal volume during CPR?

Answer 3

10 mL/kg

Question 4

What are the two reasons to avoid hyperventilation during CPR

Answer 4

• increased intrathoracic pressure impeding venous return
• hypocapnia causing cerebral vasoconstriction»_space; decreased perfusion

Question 5

What are the 3 phases of ischemia during ventricular fibrillation?

Answer 5

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

Question 6

After an unsuccessful attemp to defibrillate, how much should the joules dose be increased?

Answer 6

by 50% - do not increase subsequent doses

Question 7

Describe how to perform open-chest CPR

Answer 7

• 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

Question 8

How does CPR prognosis between dogs and cats compare?

Answer 8

Recent prospective observational study showed cats are almost 5 times as likely to survive to discharge compared to dogs

Question 9

What is the recommended PaO2 and SpO2 target for PCA care?

Answer 9

PaO2 80-100 mm Hg
SpO2 94-98%

Question 10

What are the MAP, ScvO2, lactate goals for PCA care?

Answer 10

80-120 mm Hg or higher
70% or more
less than 2.5 mmol/L

Question 11

List 3 neuroprotective PCA care strategies

Answer 11

slow rewarming (0.25-0.5 C/hr)
seizure prophylaxis
osmotic therapy

Question 12

What percentage of dogs and cats achieving ROSC die or are euthanzied before hospital discharge?

Answer 12

79%

Question 13

What are the recommended PaCO2 targets for dogs and cats during PCA care?

Answer 13

dogs 32-43 mm Hg
cats 26-36 mm Hg

Question 14

Why is the target MAP relatively high in PCA care?

Answer 14

because cerebral autoregulation may be absent

Question 15

What is the recommendation for corticosteroid administration during PCA care?

Answer 15

• routine use not recommended
• consider low-dose hydrocortisone in patients with vasopressor-dependent shock after CPA

Question 16

Describe the cerebral injuries sustained during CPA

Answer 16

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

Question 17

List the positive/beneficial effects of targeted temperature management in CPA care (7)

Answer 17

• mitochondrial protection
• decreased cerebral metabolism
• impediment of cellular Ca influx
• reduced neuronal excitotoxicity
• reduced ROS elaboration
• attenuated apoptosis
• conrol of seizure activity

Question 18

What is the recommendation for targeted temperature management in the RECOVER guidelines?

Answer 18

2012:
* suggest cooling patients remaining comatose after ROSC to 32-34 C as quickly as possible
* maintain for 24-48 hours

Question 19

Why is sedation crucial in targeted temperature management?

Answer 19

cooling may induce shivering»_space; increased O2 consumption, metabolic rate, RR, HR»_space; diminishes positive effects

Question 20

Describe how length of CPA affects how ventilation affects brain perfusion

Answer 20

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

Question 21

List reasons why microvascular blood flow may be impeded in PCA

Answer 21

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

Question 22

List possible indications for OCCPR

Answer 22

• failure of external/closed-chest CPR
• pleural space disease
• pericardia effusion/disease
• thoracic wall trauma

Question 23

What coronary perfusion pressure cutoff has been associated with increased ROSC and survival to discharge?

Answer 23

15 mm Hg or greater

Question 24

How do CPP compare between open-chest and closed chest CPR?

Answer 24

three times greater with open chest

Question 25

Describe how to build a tourniquet for descending aorta occlusion

Answer 25

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

Question 26

What muscles have to be transected to perform a lateral thoracotomy approach for OCCPR?

Answer 26

* latissimus dorsi * serratus ventralis * scalenous * pectoralis * internal and external intercostal muscles

Question 27

What scissors should be used for the lateral thoracotomy approach for OCCPR?

Answer 27

Metzenbaum alternatively: scalpel blade important: do not use these for opening the pleura, open pleura bluntly with hemostat

Question 28

During OCCPR how do you perform a partial pericardiectomy?

Answer 28

* gasp and lift the perciardium with tissue forceps * incise pericardium with metzenbaum ventral to the phrenic nerve - extend ventrally

Question 29

After ROSC, how fast should aortic compression be released?

Answer 29

slowly over 10-15 min to minimize Ischemia-Reperfusion injury

Question 30

What is REBOA?

Answer 30

resuscitative endovascular balloon occlusion of the aorta

Question 31

Describe how you close the chest after OCCPR

Answer 31

* 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

Question 32

What is the recommendation for antibiotic administration after OCCPR?

Answer 32

After ROSC: administer appropriate-spectrum IV abx continue depending on patient status and contamination during thoracotomy