CPR Flashcards
What are the two basic components of BLS in CPR? What about ALS?
BLS: Chest compression, Ventilation
ALS: Drug therapy, electrical defibrillation
Despite performing a well-executed chest compression, how many percentage of normal cardiac output can it create?
about 30%
What are the two main goals for chest compression?
1) Provide pulmonary blood flow to carry oxygen to the body and eliminate CO2
2) Provide systemic arterial blood flow to restore organ tissue perfusion and metabolism
How long should you take to assess a patient’s condition and determine whether CPR should be initiated or not?
No longer than 10-15 seconds
1) Any delay in the initiation of CPR on a pulseless patient decreases the rate of ROSC
2) Performing CPR on a patient that is not in CPA carries minimal risks comparing to delaying CPR
- RECOVER said 5-10 sec
When does the majority of the coronary perfusion happen during CPR?
At the decompression phase of chest compression
How do you determine the coronary perfusion pressure (CPP)?
CPP = Aortic diastolic pressure - Right atrial diastolic pressure
- CPP is also known as myocardial perfusion pressure
How long does it take for CPP to reach its maximum?
About 60 seconds
Describe how to perform an effective chest compression.
1) Animal’s position: lateral recumbency
2) Rate: 100-120 compressions/min
3) Depth of compression: 1/3 to 1/2 of the chest width
4) Duration: 2 minutes
5) Operator should lock the elbows during the chest compression and not lean on the chest. The shoulder should be directly above the chest.
6) Allow the chest to recoil before the next compression
7) Allow a few seconds at the end of each cycle of chest compression to assess the ECG
Describe the cardiac pump and thoracic pump theories.
Cardiac pump: blood flow is created and directed by the direct compression and increased pressure within the heart ventricles and opening up of the aortic and main pulmonary artery valves.
- medium to large keel-chested dogs, flat-chested dogs (e.g. English bulldog, French bulldog - dorsal recumbency), small dogs and cats
Thoracic pump: blood flows is created by increased the intrathoracic pressure, which force the blood from the thorax to the systemic circulation. The heart is simply a conduit.
Diastole in RH happens during recoil when abdominal veins blood return to RA vs diastole in LH happens during compression when pulmonary vessels compressed and return blood to LA.
- Medium to large round chest dogs
What is the recommended ventilation rate and tidal volume in the RECOVER Guidelines?
10 breaths/minutes, 10ml/kg, inspiratory 1 sec
Why should the higher ventilation rate or tidal volume be avoided during CPR?
It can cause hyperventilation, which can lead to cerebral vasoconstriction due to low PaCO2. It can also increase intrathoracic pressure and impede venous return and reduce the efficacy of chest compression.
In a non-intubated patient, how do you perform chest compression and ventilation?
1) Ratio: compressions-to-ventilation = 30:2
2) 2-minute cycle for each operator
3) When performing the snout-to-mouth ventilation, the neck should be extended to align the mouth to the spine. The inspiratory time is about 1 sec.
- 2024 update discourages use of mouth to snout ventilation and encourages the use of tight fitting mask
What is the target ETCO2 in dogs and cats during CPR?
> 18mmHg
*2024 update
True or False: ETCO2 can be used to evaluate the chest compression efficacy during CPR.
True
During CPR, when the minute ventilation is constant, ETCO2 is proportional to the pulmonary blood flow
How does vasopressin work during CPR?
Activates peripheral V1 receptors located at the vascular smooth muscles
What is atropine MOA?
It binds to muscarinic cholinergic receptors as an antagonist
What is the drug to consider if the patient with VF that is not responsive to defibrillation?
Lidocaine in dogs
Amiodarone in cats
- 2024 update
What is the dose for naloxone during CPR as opioid reversal?
0.04 mg/kg IV/IO
What is the dose for flumazenil during CPR as benzodiazepine reversal?
0.01 mg/kg IV/IO
During CPR, under what condition will you consider sodium bicarb and what is the dose?
Prolonged CPR (i.e. 10-15 minutes)
1 mEq/kg slow IV
During CPR, should you supply the patient with 100% oxygen or not? What is your rationale?
Ideally, the patient should maintained normoxemic (PaO2 80 - 105 mmHg). If we can get an arterial blood gas, supply the oxygen to target at normoxemia. If we can’t get an arterial blood gas, the risk of hypoxemia likely outweighs hyperoxemia and supplying patient with 100% oxygen is reasonable.
Describe open-chest CPR
1) Place the patient in right lateral recumbency. Identify 4-5th intercostal space (or where the elbow locates when it’s flexed)
2) Clip the hair and quickly perform a sterile preparation
3) Put on sterile gloves. Use a blade or scissors to make an incision into the thoracic cavity cranially to the rib until reaching the pleura. The incision should be from the dorsal margin of the scapula to 3-5 cm above the sternum.
4) Use a hemostat to bluntly dissect the pleura and create an opening that is big enough for the hand to enter the thoracic cavity and reach the heart.
5) Perform a pericardiectomy with a tissue forcep and Metzembaum scissor
4) Start direct cardiac massage. Make sure to compress from apex to base and do not block the aortic or main pulmonary artery outflow tract
What are the indications for open-chest CPR?
1) Pericardial effusion
2) Pleural space disease (e.g. pneumothorax, marked pleural effusion)
3) Diaphragmatic hernia or PPDH
4) Thoracic-wall trauma (e.g. flail chest, open-chest trauma, severe rib fractures)
5) Giant breed dog with round chest
6) Intra-OP for open abdominal or thoracic surgery
Compared to external chest compression, how much can the coronary perfusion pressure be improved with internal cardiac massage?
Three times
Describe Rumel tourniquet.
- Prepare 12 Fr or 18 Fr red rubber catheter, umbilical tape, mosquito hemostat, scissors
- Cut the distal part of red rubber catheter into 3-4 cm segment at the end.
- Pass the umbilical tape around the descending aorta with both end facing outward
- Pass the hemostat through the cut red rubber catheter. Grasp both end of the umbilical tape and thread them through the red rubber catheter.
- Move the red rubber catheter toward the aorta till the aorta is compressed.
- Use the mosquito hemostat to hold the umbilical tape at its exit at the red rubber catheter in a perpendicular angle to keep the aorta compressed
True or False: Animals undergo CPA under the care of anesthesia service are 15 times more likely to achieve ROSC than animals in other services in the hospital.
True
- Survival rate: about 50%
In veterinary medicine, how many percentage of animals died or are euthanized after ROSC before hospital discharge?
85%
What are the three phases of ischemia during VF?
Electrical phase:
- first **4 minutes **
- Minimal ischemic damage and adequate cellular energy store for metabolic process
Circulatory phase:
- subsequent 6 minutes
- Reversible ischemic damage
Metabolic phase:
- After 10 minutes
- Irreversible ischemic damage
During CPR, if the duration of VF is known to be longer than 4 minutes, how do you manage it?
Perform a complete chest compression cycle before defibrillation
Describe two different electrical defibrillation modalities.
Monophasic defibrillation
- Create a unidirectional current between the paddles and across patient’s chest
- 4-6 J/kg
Biphasic defibrillation
- Create a current in one direction between the paddles and across patient’s chest and create a second current in the opposite direction
- 2-4 J/kg
Describe how to perform electrical defibrillation.
1) The patient should be placed in dorsal recumbency if possible on an insulated surface.
2) A copious conducting gel should be applied on the paddles. Place the paddles on both sides of patient’s chest at the costochondral junction across the heart.
3) Charge the paddles according to the modality (biphasic: 2-4 J/kg)
4) Prior to deliver the current, make a loud and clear announcement of “CLEAR” and make sure no one has any physical contact to the patient.
5) After the defibrillation, perform another cycle of CPR and then reassess the ECG
Metabolic consequences of CPA
- sepsis-like syndrome
- CV instability
- poor glycaemic control
- CIRCI
*brain injury - myocardial dysfunction
During PCA care, early hemodynamic optimization is an important part. What are the targets in this part of management?
MAP 80-120 mmHg
SCvO2 > 70%
Lactate < 2.5 mmol/L
CVP < 10 mmHg
What is the target for respiratory management in PCA care?
Normoxemia (SpO94-98%; PaO2 80-100mmHg)
Normocapnia (PaCO2 of 32–43 mm Hg in dogs and 26–36 mm Hg in cats)
What is the target core body temperature for mild therapeutic hypothermia?
32 - 34 C
True or False: MTH should be initiated in dogs and cats that remain comatose as soon as possible after ROSC and maintained for 24–48 hours if mechanical ventilation and advanced critical care capabilities are available.
True
- If advanced critical care capabilities including mechanical ventilation are not available, MTH should not be initiated
This is no longer the case in the 2024 update.
The guidelines do not recommend the active induction of hypothermia (therapeutic hypothermia) after ROSC in dogs and cats. Unlike in human medicine, where targeted temperature management is often used, there is insufficient evidence to support its routine use in veterinary patients.
It is crucial to avoid hyperthermia, as it can worsen neurological outcomes. The guidelines recommend maintaining the animal’s body temperature within the normal physiological range (generally between 37.5°C to 39.2°C or 99.5°F to 102.5°F for dogs and cats).
If the body temperature exceeds this range, active cooling measures should be implemented to bring it back to the normal range.
For animals that are hypothermic post-ROSC (with a body temperature below the normal range), the guidelines recommend a gradual rewarming process. Rapid rewarming should be avoided to prevent complications such as reperfusion injury or hypotension.
What is the recommended rewarming rate during PCA care in RECOVER Guideline?
0.25 - 0.5 C/hr
True or False: Clinical neuro exam at the first 24 hours of ROSC does not predict poor prognosis.
True
It may take up to 72 hours.
What is the only therapeutic intervention that has been shown to attenuate myocardial dysfunction in PCA care?
Mild therapeutic hypothermia
Define myocardial stunning.
A transient, reversible myocardial dysfunction without cell necrosis after acute ischemic injury.
Worsened by:
* myocardial no-reflow (endothelial damage, microthromby and decreased RBC deformability)
* use of epinephrine
* use of defibrillator
Describe interposed abdominal compressions
During the recoil phase a second rescuer applies a positive pressure to the abdomen to increase pressure over the vena cava and facilitate venous return to the heart
Target pressure 100mmHg, push dorsally not laterally to avoid spleen and liver injury
What is the benefit of interposed abdominal compressions?
improved cardiac perfusion pressure and outcomes in human studies
Discuss beta effects of epinephrine during CPR
- pros:
- vasodilation of coronary arteries
- increased cerebral blood flow
*cons:
- increased myocardial oxygen consumption
- decreased hypoxemic pulmonary vasoconstriction
- impaired microcirculation
- increased risks of tachyarrhythmia
Treatment for TdP
Magnesium IV
Is coarse or fine VF better in terms of prognosis?
Coarse (waves >3mm)
What is an impedance threshold device?
Device to apply at the end of the ET tube during CPR to increase negative intrathoracic pressure during recoil –> improves venous return
There’s a linear relationship between supranormal oxygen tension post CPA and in-hospital mortality. An increase in 25mmHg paO2 = an increase of ___ % mortality while an increase in 100mmHg = an increase in ____ % mortality
6%
24%
POCUS during CPR
POCUS during CPR is to monitor for any potential recovery signs or specific conditions that might be affecting the heart’s ability to restart
-
Assessing Cardiac Standstill :
If there is complete standstill with no movement, it suggests a poor prognosis, and providers may consider stopping resuscitation in some cases, especially if combined with other factors. -
Detecting Organized Cardiac Activity :
The heart might show organized contractile activity, even if there’s no palpable pulse. This is often called pseudo-PEA (pulseless electrical activity), where the heart is beating weakly but not enough to generate a pulse. -
Assessing for Reversible Causes :
POCUS can help detect treatable conditions such as cardiac tamponade, pulmonary embolism, or hypovolemia that may be causing cardiac arrest. - Identifying Return of Spontaneous Circulation (ROSC)
