CPR Flashcards
Goal - CPR
support body, restart circulatory and respiratory systems
Success rate - animal CPR
low, about 10% (animals under GA have a better success rate as this is a reversible cause of CV or respiratory arrest vs terminal diseases and close monitoring allows prompt detection of arrest)
When is CPR most likely to be effective?
before major organs have undergone a prolonged period without blood supply
Define respiratory arrest
cessation of effective breathing
Define CPA
Cardiopulmonary arrest = cessation of effective CO and respiration
Define ROSC
Return of spontaneous circulation = re-establishment of sustained CO without assistance
Define BLS
= basic life support
- chest compressions and assisted ventilation
What is ACLS?
- Advanced cardiac life support
- BLS + medical + electrical interventions
What is CPR?
= resuscitative efforts (BLS and/or ACLS) required to elicit ROSC and emphasising the importance of neurological outcome
Factors to consider performing CPR
- owner’s wishes
- nature of underlying dz
- QoL should resuscitation be succesful
- availability of ongoing intensive care
- finances
What happens if CPR is initially succesful?
= result in restarting heart beat, detectable circulation (i.e. ROSC) and spontaneous ventilation
- ongoing management (24-48hrs, depends on patient health status) can be highly intensive, demand continuous nursing, monitoring, expensive
- many cases, high risk of a crash recurring (>80% animals rearrest within 24 hours)
Long-term survival of patients undergoing cardiopulmonary arrest
poor to grave (people - poor)
What % animals are discharged after CPR?
-
Name different resuscitation statuses
- DNR
- Closed-chest CPR
- Open-chest CPR
- establish before CPA
When is a DNR order appropriate?
- hopeless prognoses (metastatic neoplasia, end-stage CRF, end-stage CHF, end-stage hepatic failure, profound neurological dysfunction, DIC, overt coagulopathies, owner’s wishes, inability to provide adequate post-resuscitation care and finances)
How do you recognise CPA?
- can be harder than you think!
- ABC triage (airway patent, breathing efforts, circulation - audible heart sounds, palpable pulses)
- often preceded by hypoventilation and bradycardia
- don’t rely on MM alone (respiratory distress may be cyanotic or grey but some patients have a normal CRT minutes following death)
Impending signs of CPA
- certain arrhythmias –> degenerate into potentially fatal arrhythmias (VT, ventricular flutter, 3rd degree AV block)
- other ECG changes (atrial standstill, ST depression, R on T phenomenon)
- sustained tachycardia that doesn’t respond to appropriate fluids
- patients where dyspnoea cannot be alleviated
- patients with refractory hypotension despite adequate therapy
- severe metabolic acidosis (pH 9mmol/L)
- high vagal tone (patient population at risk, sometimes in these individuals, stimulating vagu nerve –> life-threatening bradycardia aka vasovagal syncope and vagal arrest)
When can vagal stimulation occur?
- V
- defecation
- respiratory/abdominal dz (esp splenic diseases)
- ocular or neck sx
Action - when a vasovagal arrest is recognised
- provide O2
- give atropine (refer to emergency dosage chart)
What is needed to provide CPR in CPA cases?
- provide O2
- perform CPR
- crash cart/box
- monitoring equipment (at least an ECG)
What should a crash box include?
ESSENTIAL: - ETT - IV catheters - bandaging material - laryngoscope - syringes/ needles - drugs OPTIONAL (BUT IDEAL): - defibrilator - scalpel blades - suture material - IV fluids - pressure bag - ETCO2 monitor
Personnel resources - CPR
- minimum 3 people
1. provide ventilation
2. compression
3. written record and/or get necessary equipment or other items
(4. another person to evaluate for effective pulse generation from compressions and monitor to TOSC) - a team leader must take responsibility for ‘running the crash’
What is the first step of CPR?
- can start alone
- secure Airway, Breathe for the patient and get Circulation going by chest compressions (start compressions before intubating!!!)
How do you secure the airway in CPR?
- ETT intubation
- verify correct placement (laryngoscope, palpate neck to ensure you feel ‘only 1 tube’ - that being an ETT within trachea)
- hold tube in place until securely tied and then inflate cuff
- right lateral recumbency
- continuous ECG (NOT spirit but coupling gel)
How do you provide positive pressure ventilation in CPR? How many breaths/minute?
- 100% O2 (via an Ambubag)
- connected to O2 supply or anaesthesia machine
- 12-15 breaths/minute (more breaths is detrimental)
- ensure assisted breathing leads to adequate thoracic expansion
Why is hyperventilation not desired in CPR?
–> increases in intrathoracic pressure which compromises CO and reduces cerebral and coronary perfusion
What to do if you encounter difficulty ventilating a CPR patient:
CHECK FOR: - Displacement of tube - Obstruction of tube - Pneumothorax - Equipment failure (REMEMBER by the acronym 'DOPE')
How do you perform chest compressions? how does it vary for cats and small dogs vs. larger dogs?
- already under GA –> consider direct cardiac massage
- CLOSED-CHEST: either cardiac pump or thoracic pump theory are appropriate
- small dogs and cats: compressions should encompass heart from both sides (hands both sides of chest = cardiac pump theory)
- larger dogs (>7kg): compression should be focused on widest part of chest (thoracic pump theory)
- done forcefully but let thorax spring back completely
- switch after 2 minutes
- OPEN-CHEST CPR: for very large dogs (>40kg) thoracic compressions may be ineffective and open chest CPR should be performed
How many compressions should you aim to do?
approx 100/minute (v important)
Considerations for open-chest CPR
- significant pleural space dz
- pericardial effusion
- large dogs
- chest wall dz
- pericardial effusion
- penetrating chest wounds
- intra-operative arrests
- haemoabdomen
- unwitnessed arrests
- unsuccessful closed chest CPR (after 5-10 mins)
T/F: providing concurrent or interposed abdominal counterpressure is valuable during CPR
Actually this is unknown
- interposed abdominal compressure with each breath almost impossible so limited value
- continuous abdominal pressure (to limit back-flow of blood from heart) if sufficient personnel are present
Outline how to perform ACLS. How does this vary with different ECG findings?
- once BLS begins, the normal progression is to start ACLS
- administer drugs with hope of achieving ROSC
- must interpret ECG for this:
> some electrical activity on ECG + no detectable pulse this is Pulseless Electrical Activity (PEA) –> adrenaline
> absensce of any electrical activity (asytole) –> adrenaline
> ventricular fibrillation –> electrical defibrillation
> sinus bradycardia –> atropine
> sinus tachycardia –> lidocaine
Outline use of adrenaline
- adrenergic agonist
- used to ‘restart’ the heart in patients with asytole or PEA
- standard vasopressor for cardiac arrest
- alpha-mediated vasoconstriction
- increases aortic pressure
- increases myocardial perfusion
Outline use of atropine in CPR
- vagolytic drug
- increases HR once it has restarted or reverse a vasavagal event
- avoid inducing tachycardia as this will increase O2 demands of the heart
- for vagally mediated arrests and severe bradycardia
- parasympatholytic
- accelerates pacemakers
- increases AV conduction
- routine use may not improve outcome
- may potentiate sinus tachycardia
- may encourage VF if given with epinephrine
Outline use of lidocaine in CPR
- used to treat fast VT before they degenerate into fibrillation
- decreases automaticity
- suppresses ventricular arrhythmias
- less effective than amiodarone
How are drugs administered during CPR?
- through existing catheters
- catheres placed via cut-downs
- via intra-osseous catheters
- intra-tracheal catheters
- last resort route = intra-cardiac injections
- through ETT (double dose and follow with 10 sterile water - a hypotonic solution to increase absorption, follow with big breath from Ambu bag or anaesthesia machine)
What other drugs may be useful during CPR?
- calcium gluconate (v slowly, IV, 3ml for cat, 5ml small dog, 10ml large dog) if severely hypocalcaemic or hyperkalaemic
- sodiumm bicarbonate (1 mEq/kg usually = 1ml/kg, IV over 20-30minutes) if pH
Outline fluid administration during CPR
- to help circulate drugs that are administered
- vital with hypovolaemia (one of commonest causes of arrest)
- give via pressure bags
+/- administer colloids or hypertonic saline - only CI is when fluid overload caused the arrest
Outline defibrillation in CPR
- usually trained individual
- everyone must be alert and respond to ‘CLEAR’
- only coupling gel should be used to improve skin contact (NEVER SPIRIT)
- voltage (joules) should be determined from crash cart chart: usually 100J for cats and small dogs, 200J larger dogs, 50J for internal defibrillation (open-chest CPR)
Ouline post-resuscitation challenges to overcome
- severe neurological dysfunction
- myocardial injury
- rib fractures
- renal failure
- ‘shock gut’
- DIC
- respiratory failure
- monitor for these and tx appropriately
How long is a successful CPR patient in a critical state?
- at least next few hours (if healthy beforehand)
- if systemically ill before or were undergoing invasive sx (may remain critical for at least 2-48 hours). High risk of cardiac or respiratory arrest recurring. Thus close monitoring, appropriate support until CV and respiratory function return to normal.
Indications - CPR
patient that has arrested or is having an impending arrest
T/F: sometimes you have a heart beat but not CO
True - this is still a cardiac arrest
What is the 1st goal of CPR?
ECG rhythm + pulse
What happens in R on T phenomenon?
- this is an arrhythmia that is an impending sign of a CPA
- electrical pulseline doesn’t return to baseline
Behavioural signs - impending CPA in a cat
- lateral recumbency
- open mouth breathing
- thrashing
What type of arrest do animals/ humans usually have?
- ANIMALS: respiratory arrest (focus on compressions first)
- HUMANS: cardiac arrest
What is the 50:50 duty cycle?
refers to time spent doing chest compressions versus time spent waiting for the chest to recoil.
T/F: time b/w VF onset and defibrillation is inversely correlated with survival.
True
What drugs can you administer by ETT?
- lipid soluble only
- acronym ‘NAVEL’:
= Naloxone, Atropine, Vasopressin, Epinephrine, Lidocaine - never give Ca or bicarbonate through ETT.
Outline use of vasopressin in CPR
- vasopressor
- some thorectical advantages over epinephrine
- limited data
- inconsistent results
- only need to give once
Advantages - open chest CPR
- diastolic filling assessed
- pericardial tamponade avoided
- aorta can be cross-clamped
- VF visually diagnosed
- myocardial flaccidity assessed directly
Disadvantages - open-chest CPR
- experienced personnel
- more personnel
- significant step
- finances and sx
- risk of infection
Complications post-CPR
- blindness
- dysphoria (dissatisfaction with life)
- neuro dysfunction
Determinants - CPR termination
- time between CPA and starting CPR
- length of resuscitative efforts
- comorbidity
- senior staff consensus
- inform owner early
- VF survival decreases by 7-10%/min
- > 12 mins survival is 2-5%
- ROSC >30 mins or >10 mins asystole
