CPR

Question 1

Compressions

Answer 1

100bpm
1/3-1/2 width of thorax
swap q2min
lateral if keel, dorsal if barrel (bulldog)
<10kg over heart, >15kg widest chest

Question 2

Steps at CPA

Answer 2

1. Check for heart beat
2. Start compressions
3. Someone else checks airways - patency, intubate - ventilate
4. ALS

Question 3

Ventilation

Answer 3

10bpm
<30cm H2O
TV = 10ml/kg

Aim ETCO2 >15mmHg

Question 4

NAVEL drugs?

Answer 4

Naloxone
Atropine
Vasopressin
Epinephrine
Lidocaine

Question 5

Intraosseous sites

Answer 5

• proximal humerus
• intertrochanteric fossa of prox. femur
• tibial tuberosity
• wing of iliac

Question 6

MOA of atropine

Answer 6

anticholinergic drug that binds to and antagonises muscarinic cholinergic receptors, leading to w/drawal of parasymp. stim.

Question 7

atropine dose in CPA

Answer 7

0.04mg/kg q3-5min

Question 8

MOA of epinephrine

Answer 8

a sympathomimetic drug that binds to and antagonises the alpha and beta adrenergic receptors
Alpha – vasoconstriction
Beta - chrono + inotrope

Question 9

epinephrine dose

Answer 9

0.01mg/kg q3-5min

Question 10

Vasopressin MOA

Answer 10

non-adrenergic vasopressor that binds to and agonises the V1A receptor on vasc. smooth muscle causing vasoconstriction

Question 11

advantage of vasopressin over epinephrine

Answer 11

functions better in acidic environments (CPA often acidic environment dt lack of tissue perfusion)

Question 12

opioid reversal

Answer 12

naloxone

Question 13

dexmedetomidine, medetomidine reversal

Answer 13

atipamezole

Question 14

xylazine reversal

Answer 14

yohimbine

Question 15

benzos reversal

Answer 15

flumazenil

Question 16

Amiodarone MOA

Answer 16

potassium channel blocker used to tx patients w/ a perfusing ventricular arrhythmias, defibrillation resistant pulseless ventricular tach/fib

Question 17

Lidocaine MOA

Answer 17

class 1b antiarrhythmic –> sodium channel blocker to tx. pulse ventricular tachy/fibs

Question 18

indications to use calcium gluconate

Answer 18

IF there is documented ionized hypocalcaemia OR documented hyperkalaemia during CPR resulting from poor tissue perfusion + subsequent cell death

Question 19

indications to use sodium bicarbonate

Answer 19

only if severe metabolic acidosis prior to CPA

Question 20

a large spike in end-tidal CO2 is indicative of…

Answer 20

ROSC

Question 21

> 20mmHg ETCO2 in cats indicates..

Answer 21

adequate chest compressions in closed chest CPR

Question 22

> 15mmHg in dogs indicates…

Answer 22

adequate chest compressions in close-chest CPR

Question 23

How do you use an ECG during CPR?

Answer 23

leads places, compressions stopped for <10sec every 2min to allow interpretation of heart rhythm

Question 24

what is the goal of electrical defibrillation?

Answer 24

depolarise all of myocardial tissue simultaneously to achieve asystole in hope that a pacemaker cell will take over to generate a perfusing rhythm

Question 25

when is electrical defibrillation indicated?

Answer 25

pulseless ventricular tachy/fibrillation are the only pulseless rhythms that should be treated w/ electrical defib ASAP once IDed

Question 26

what dose of fluids is recommended during CPA?

Answer 26

a full shock dose (unless arrested dt congestive heart failure)

Question 27

Myocardial perfusion is dictated by...

Answer 27

perfusion pressure (CoPP) = the difference between the pressure at the starting point in the aortic sinus (DAP = diastolic aortic pressure) and the pressure at the finishing point (RAP = right atrial pressure)

Question 28

CoPP =

Answer 28

DAP - RAP

Question 29

CoPP >/= (???) in order to achieve ROSC

Answer 29

25mmHg

Question 30

describe the thoracic pump theory

Answer 30

>15kg animals - when pressure is applied to the widest part of the thoracic cavity, intrathoracic pressure is maximally increased forcing blood w/in the large vessels either out of the thorax via the aorta, or up to and through the heart via the intrathoracic CV. Valves w/in veins prevent backward flux of blood out of the thorax. Chest recoil post compression causes pressure w/in thorax to decrease, opening large vessels and allowing them to fill w/ blood from extra-thoracic space.

Question 31

describe the cardiac pump theory

Answer 31

<10kg animals - blood flow during chest compression where the hand is directly over the heart, is dt compression of the ventricles btwn the lateral chest walls (in lateral recumbency) or btwn the sternum and spine (in dorsal)

Question 32

how is the preload provided for next cardiac cycle in CPR?

Answer 32

after the compression, chest recoil occurs as ribs return to normal anatomic position --> creates low pressure region w/in thorax drawing blood to fill the heart and great veins --> provides preload for next cardiac cycle

Question 33

what are the risks of hyperventilating a patient during CPR?

Answer 33

decreased venous return and preload, decreased CO and compromised CoPP and decreased ROSC/survival dt persistent positive pressure on the thorax

Question 34

explain the theory of interposed abdominal compressions

Answer 34

- performed by 2 people - abdominal and chest compression alternatively - increases abdominal pressure during diastole forces abdominal aortic blood cranially towards the aortic sinus --> inc DAP --> inc CoPP - inc. CO by improving venous return to heart via compression of CdVC - -> v. technically challenging

Question 35

why might the application of constant pressure to the abdomen be beneficial in CPR?

Answer 35

= abdominal counterpressure | - may improve blood flow through cranial body by decreasing blood flow through abdominal aorta

Question 36

when is it reasonable to stop CPR?

Answer 36

after 20-30mins w/ no ROSC

Question 37

Characteristics of pulseless electrical activity on ECG?

Answer 37

- coordinated electrical activity/repeats - rates <200bpm (commonly <50bpm) - narrow QRS complexes commonly (but can look like normal sinus rhythm or have wide/bizarre complexes)

Question 38

characteristics of asystole on ECG?

Answer 38

- no electrical activity/flat line

Question 39

name the two common non-shockable rhythms

Answer 39

- PEA | - Asystole

Question 40

name the two common shockable rhythms

Answer 40

- pulseless VTach | - VFib

Question 41

characteristics of pulseless VTach?

Answer 41

- organised, rpt, wide QRS complexes | - >200bpm w/out accompanying pulses

Question 42

characteristics of Vfib?

Answer 42

- wavy, chaotic line (lack of consistent, rpt waveform) | - fine (low amp, high freq) vs. coarse (high amp, low freq)