CPR Flashcards
What are the three most common anesthetic complications?
hypoventilation (63%), hypothermia (53%), hypotension (38%)
Hemorrhage
Acute: hypovolemia, decreased d blood oxygen carrying capacity
Detectable at 10-20%, life-threatening circulatory failure if 30-40%
Clinical Signs of Hemorrhage
tachycardia, decreased pulse pressure/area under pulse arterial waveform, peripheral VC/pale MM
Treatment of Hemorrhage
Crystalloids 3x volume shed blood DT rapid extravasation of fluid
Dilution will occur: further dilute HCT, concentration of clotting factors/platelets, decreased oxygen carrying capacity, although improved CO
Likely will need blood +/- components
Most common arrhythmias seen in canine patients under GA?
o VPCs warrant treatment if: R on T, multifocal, >180bpm, perfusion
Traumatic Myocarditis
- Patient with traumatic myocarditis (trauma, HBC), arrhythmias, myocardial dysfunction peak ~ 24-48 hrs
RECOVER
Reassessment Campaign on Veterinary Resuscitation
Outcomes associated with CPR
100 patients undergo CPR: regardless of why experienced CPA, should get ROSC rate ~45%
Cats generally 42-44%, dogs 28-35%
Once CPA occurs, will lose 50% of patients best to prevent CPA
Survival to Discharge: Cause of CPA Matters
Perianesthetic 40-45% will survive to go home
ICU ~5-7%
o 20-90% of patients achieve ROSC in will die in PCA period
Risks Assoc with CPR
Rib fx – 1.6%
Muscle damage – 1.4%
Chest pain – 11.7%
Circulation Detection
Dorsal pedal palpable if MAP >60mm Hg
Apex beat: 4-6th ICS, lower 1/3 chest or elbow caudal to level of costochondral junction
Pulses should be palpated even if heart beat ausculted: apneic patients with inadequate contractility to generate blood flow sufficient to produce palpable pulses may still require chest compressions
No longer recommended to check pulses in apneic patients
DDX absence of pulses
o Severe shock
o Marked decreased contractility
o Pericardial effusion with tamponade
o Severe pleural space dz
Most Important Step when CPA Identified?
START BLS!!
preserve organ function
Promote circulation of RBCs oxygen delivery to tissues
Within 10’ of CPA, irreversible ischemic damage to tissues, decreases likelihood of successful ROSC
ALS techniques only applied once BLS perforated
At-Risk Patients for CPA
o 5 Hs: hypovolemia, hypoxia, hydrogen ions, hyperkalemia, hypoglycemia
o 5 Ts: toxins, tension pneumothorax, thromboembolism, tamponade, trauma
Main Cause of Canine, Feline CPA?
primary respiratory arrest more common with secondary cardiac arrest DT hypoxemia that develops from lack of ventilation
Horses: primary cardiac arrest
What are the most common arrest arrhythmias?
Pulseless electrical activity
Asystole
Doses of Emergency Drugs: epinephrine
High dose 0.1
Low dose 0.01mg/kg
Doses of emergency drugs: vasopressin
0.8U/kg
Doses of Emergency Drugs: Atropine
0.04-0.05mg/kg
Doses of Emergency Drugs: Amiodarone
5mg/kg
Doses of Emergency Drugs: Reversal Agents
Naloxone 10-40mcg/kg
Flumazenil 0.01mg/kg
Atipamezole 50mcg/kg
Defibrillation: monophasic, external
2-10J/kg
Defibrillation: monophasic, internal
0.2-1J/kg
Defibrillation: biphasic, external
2-4J/kg
Defibrillation: biphasic, internal
0.2-0.4J/kg
Components of BLS
Chest compressions
Ventilation
Components of ALS
–Monitoring
–Vascular Access
–Reversals
–Evaluation of ECG once monitoring
VF/Pulseless VT Algorithm
Continue BLS, charge defibrillator
Give one shock (or precordial thump)
If prolonged:
Amiodarone, lidocaine
epi, VP every other cycle
Increase defibrillation dose by 50%
Asystole/PEA Algorithm
-Low dose epi +/- VP every other BLS cycle
-Atropine every other BLS cycle
Prolonged >10’:
-High dose epi
-Bicarbonate therapy
Open Chest CPR Contraindications
contraindicated in small dogs <10kg, cats unless in sx DT size of chest cavity and difficulty assoc with cardiac massage in these patients
Importance of Good Compressions during CPR
o Only thing generating CO during arrest = compressions
o Ideal compressions: achieve 25-30% normal CO = without high-quality BLS, chances of ROSC minimal
Compression rate: 100-120/min, compression depth 1/3-1/2 width of thorax
Cycles = 2’
Consequences of compression rates >100-120bpm?
Higher compression rates decrease CO bc do not allow full elastic recoil of chest –> decrease return of blood to heart –> decrease CO
Why are cycles 2’?
- Cycle = 2’ bc takes 1’ chest compressions for aortic BP to reach steady state that provides perfusion to heart/tissues
- Cycles <2min decrease perfusion bc steady state not achieved or maintained
Consequences of chest compressions in small dogs, cats
possible to overwhelm chest: overt chest trauma, myocardial contusion
Larger patients: large amount of force to obtain effective compressions
Abdominal Compressions
Must be coordinated with partner, alternate timing
Can increase venous return, with possible increases in CO
Medium sized dogs or greater
Normal Canine Cardiac Output?
100-200mL/kg/min
Normal Canine Stroke Volume?
1-2mL/kg
Cardiac Pump Theory
Direct compression of heart (LV/RV) generates blood flow
Key: forward flow of oxygenated blood to tissues accomplished via direct compression of heart
* Increased pressure in ventricles to close AV valves, prevent backflow of blood into atria
o Goal: provide maximum SV with each compression
How Heart Fills with Cardiac Pump Theory
- Elastic recoil to chest, heart btw compressions creates negative pressure within heart to allow ventricular filling for next compression
Patient Populations for Cardiac Pump Theory
Cats, small dogs, larger keel-chested dogs
* High thoracic compliance
* Narrow, triangular shaped chests
Heart right up against rib case, able to compress ventricles directly to generate blood flow
One or two handed technique depending on patient size
Limitation of Cardiac Pump Theory
Older or obese animals with less compliant chests: chest may be too stiff to employ cardiac pump theory DT normal aging changes or SQ fat
Thoracic Pump Theory
Key: forward flow of oxygenated blood to tissues accomplished via indirect compression of aorta increasing intrathoracic pressure
* Should maximally compress thorax
Change in intrathoracic pressure causes blood flow
Heart During the Thoracic Pump Theory
Heart = passive conduit
o MV, TV not closed during chest compressions – blood flowing passively through heart
* Drive intrathoracic pressure high to push blood out
Maximal change in thoracic volume = hands over widest part of chest
Patient Population for Thoracic Pump Theory
Medium, large round-chested dogs; unable to directly compress heart
heart filling with thoracic pump theory
Recoil of chest btw compressions causes negative pressure within thorax = draws blood into cr/cd VC, heart
Blood drawn into lungs during recoil phase DT expansion of highly compliant pulmonary vessels
Key points of Two Handed Technique
o Hips patient height or higher = step stool, climb on table, move patient to floor
o Heels of hands stacked with elbows over hands, shoulders over elbows
o Bend from hips only
o Overlap hands with fingers interlocked, heel of upper hand directly over heart
o DO NOT LEAN - Must allow chest to recoil
Which are the two shockable rhythms?
Pulseless VT
Ventricular fibrillation
Which recumbency is preferred for CPR per RECOVER guidelines?
Lateral