ALS Flashcards
When should an AED be used instead of a manual defibrillator
When someone trained to use a manual defibrillator is not immediately available
When only an AED is available
What is used to confirm correct tracheal tube placement during resus
Waveform capnography
If there is risk of cervical spine injury how do we initially secure the airway in an unresponsive patient?
Jaw thrust or chin lift in combination with manual in-line stabilisation (MILS) of the head and neck by an assistant. If airway obstruction persists add head tilt a small amount at a time until airway is open (oxygenation, ventilation prioritised over cervical spine injury)
Correct hand placement for chest compressions
middle of lower half of sternum
Features of high quality chest compressions
Depth 5-6cm
Rate 100-120 bpm
Chest recoil completely after each compression
Same amount of time for compression and relaxation
Minimise interruptions
Maximum time for chest compression interruption for endotracheal tube insetion
5s
Ventilation rate in resuscitation
10 breaths/min
Maximum time for chest compression interruption for pulse check
5s
What do you do if a patient is not breathing and has a pulse?
Ventilate/secure airway
Check for a pulse every minute
If any doubts about presence of a pulse, start compressions
What do you do in a monitored and witnessed cardiac arrest?
Confirm cardiac arrest
If VF/pVT, 3 successive (stacked) shocks
Check for pulse after each defibrillation attempt
If still no pulse after 3rd shock, start compressions (3 shocks counted as 1 shock in ALS algorithm)
When do you consider a precordial thump?
When it can be used without delay whilst awaiting on the arrival of a defibrillator in a monitored VF/pVT arrest
(Use ulnar edge of tightly clenched fist to delivver a sharp impact to lower half of the sternum from a height of 20cm, with immediate retraction of fist)
What proportion of cardiac arrests have shockable (VF/pVT) rhythms?
20%
Can cardiac arrest rhythms change into another arrest rhythm?
Yes - 25% of PEA/Asystoles can change into VF/pVT rhythms
Whilst charging the defibrillator what should happen?
Chest compressions should be continued
Where should pads be applied?
Under right clavicle anteriorly and on left mid-axillary line
What energy setting should shocks be given at in a cardiac arrest?
120-150J for 1st shock, then at same or higher settings for subsequent shocks
After a shock is given, what should happen?
Don’t stop for pulse check.
Immediately restart chest compressions
In shockable rhythm, which medications do you give and when?
Adrenaline 1mg IV after 3rd shock, then after every alternate shocks (approx 3-5minutes)
Amiodarone 300mg IV after 3rd shock, amiodarone 150mg IV after 5th shock
Lidocaine 1mg/kg can be used as alternative if amiodarone not available, but not to be given when amiodarone already given
Reversible causes of cardiac arrest
4Hs:
Hypoxia
Hypothermia
Hypo/hyperkalaemia, hypoglycaemia, hypocalcaemia, other metabolic disorders
Hypovolaemia
4Ts:
Tension
Thrombosis
Tamponade
Toxins
Dose of adrenaline
1mg IV
Dose of amiodarone
300mg IV, then 150mg IV after 5th shock
Why are compressions continued immediately after a shock?
- Minimise chest compression interruptions
- Even if shock successful, rarefor pulse to be immediately palpable (ROSC to palpable pulse may be longer than 2 minutes in 25% of shocks)
- Even in ROSC, compressions do not increase chance of VF recurring
- If shock resulted in asystole, compressions may usefully induce VF
In persistent VF/pVT arrest what should you also do?
Check positioning of pads after shocks and consider changing them to anterior posterior or other positions
When should PULSE checks be done?
Only when RHYTHM on monitor is compatible with a pulse, otherwise, don’t waste time
In a witnessed cardiac arrest with shockable rhythm, when do you give adrenaline and amiodarone
Give adrenaline after the ‘3rd’ shock (Ie the 5th shock including the 3 stacked shocks)
Give amiodarone after the initial stacked shocks
What is paramount in managing a PEA arrest?
Treating the reversible causes of cardiac arrests
What special consideration should be given when asystole is suspected during CPR?
Ensure ECG pads attached to chest, correct monitoring mode selected
Ensure gain setting appropriate
Check ECG carefully for presence of P waves, as if present they may be treated with cardiac pacing
When to give adrenaline in PEA/Asystole?
1mg IV immediately then every alternate cycle (3-5 mins)
When should chest compressions be interrupted for ventilation?
If excessive gas leakage causes inadequate ventilation of patient’s lungs, interrupt compressions to allow for 30:2 ratio
What is the key value measured by waveform capnography?
end-tidal PaCO2
What is waveform capnography used for?
- Ensuring tracheal tube placement
- Monitoring ventilation rate
- Monitoring chest compression quality (high End-tidal PaCO2 with increase with increased ventilation rate and compression depth)
- Identifying ROSC (increased end-tidal PaCO2 may help indicate ROSC)
- Prognostication during CPR (lower end-tidalPaCO2 associated with ower ROSC rates, increased mortality)
Which sample is waveform capnography measuring?
A continuous sample of gas. (connector placed in breathing system usually on end of tracheal tube or supraglottic airway device)
- so end-tidal PaCO2 would be measuring the partial pressure of the gas in the airways just at the end of the expiratory phase
Normal range of end-tidal PaCO2?
4.3-5.5kPa
When would you suspect a Tamponade as the cause of a cardiac arrest?
- Penetrating chest trauma
- Post-cardiac surgery
- Post-device implantation (eg pacemaker)
- Post PCI
How would you treat cardiac tamponade?
- Pericardiocentesis
- Resuscitative thoracotomy
What should you do to exclude toxins as a cause of cardiac arrest?
Review drug chart and exclude any history suggestive of overdose
What should you beware of regarding intubation in the context of a possible tension pneumothorax?
Check tube position - intubation of right main bronchus may complicate tension pneumothorax further
How would you spot a tension pneumothorax in a cardiac arrest situation?
Clinically:
- Tracheal shift
- Unilateral chest expansion
- Subcutaneous emphysema
Investigations:
- Pleural ultrasound
- Chest X-Ray
What can you do for hypothermia
Active rewarming
If that fails, cardiopulmonary bypass if facilities available
What does hypovolaemic causes include?
haemorrhage, loss of fluids eg diarrhoea, sepsis, anaphylaxis
Basically many forms of hypovolaemic and distributive shock
4 types of shock
Hypovolaemic
Distributive
Cardiogenic
Obstructive
When does hypoxic brain injury start to set in?
Within 3 minutes of a VF/pVT cardiac arrest
Four non-technical skills that are essential in cardiac arrests
Situational Awareness
Leadership
Decision-making
Task management
How much flush is required for any peripherally injected drugs?
20ml Saline
Should also have elevation of the extremity for 10-20s to facilitate delivery of drug to central circulation
Where are the three recommended insertion sites for Intraosseous access?
Proximal Humerus
Proximal Tibia
Distal Tibia
Contraindications for intraosseous access
If at the target site there is:
- Trauma
- Infection
- Prosthesis
IO access attempt in the last 48 hours (including failed)
Failure to identify anatomical landmarks
What should you do after insertion of an intraosseous?
- Confirm correct placement - attempt to aspirate IO blood (absence does not necessarily imply failure)
- Flush needle to ensure patency, observe for leakage/extravasation (best done using extension set flushed with 0.9% saline attached to hub of needle before use)
How do you give medications via IO?
Pressure required - pressure bag or syringe to maintain flow rates
Complications of IO access
- Extravasation into soft tissues surrounding insertion site
- Dislodgement of needle
- Compartment syndrome due to extravasation
- Fracture/chipping of bone during insertion
- Pain
- Fat emboli
- Infection/osteomyelitis
If PCI or angiography is required during a cardiac arrest, what is required?
Automated mechanical chest compression device and/or extracorporeal CPR to maintain circulation during procedure
How long should you continue CPR for if fibronolysis has been given with suspicion of PE?
60-90 minutes
How would you treat a PE-driven cardiac arrest?
- Thrombolysis (eg alteplase),
- CPR for 60-90 minutes post thrombolysis
- Consider extracorporeal CPR
- Consider surgical/mechanical thrombectomy
What is the recommended position for a focused ultrasound in cardiac arrests? (eg to exclude tamponade)
- Sub-xiphoid probe position
- Can do this just before chest compressions are paused for 10s
What conditions suggest benefit for extracorporeal CPR (ECPR)?
- reversible causes of arrest
- minimal comorbidities
- witnessed arrest
- immediate CPR started
- ECPR started within 1 hr of collapse/arrest
In asystole, when is it generally accepted to stop CPR?
After 20 minutes in absence of reversible cause
How long should you observe the patient before confirming death after stopping CPR?
minimum 5 minutes
What should be done post-resus attempt?
- Ongoing patient care with allocation of further roles, responsibilities, including handover
- Documentation
- Communication with relatives
- Post-event debrief
- Ensure equipment, drug trolleys are replenished
- Ensure audit forms completed
Where is the commonest site of airway obstruction?
Pharynx (more often soft palate and epiglottis rather than tongue)
What can cause airway obstruction?
- Vomit following regurgitation
- Blood following trauma
- Secretions
- Foreign bodies
- Oedema (burns, inflamation, anaphylaxis)
- Bronchospasm
- Tumours
What often causes laryngeal obstruction?
Oedema from:
- anaphylaxis
- burns
- inflammation
Laryngeal spasm from inhalation of foreign material or stimulation
What causes infra-laryngeal obstruction comonly?
- excessive bronchial secretions
- mucosal oedema
- bronchospasm
- pulmonary oedema
- aspiration of gastric contents
What do you do for LOOK, LISTEN, FEEL?
Look for chest and abdominal movements
Listen and Feel for airflow at the mouth and nose
What sounds are audible in partial airway obstruction?
Inspiratory stridor
Expiratory wheeze
Gurgling
Snoring (pharyngeal)
Describe see saw breathing
Paradoxical chest and abdominal movement
Chest drawn in and abdomen expanding during inspiration and opposite during expiration
What features can you see in airway obstruction
See saw breathing
Use of accessory muscles
Intercostal and subcostal recession
Tracheal tug
What should you do if you suspect airway obstruction in patients with tracheostomies or permanent tracheal stomas
Remove any obvious foreign material from tube or stoma
Remove tracheostomy liner (inner tube) if one is present
I’d still not possible to ventilate, try to pass suction catheter. If this is successful, perform tracheal suctioning and attempt to ventilate. If it’s not successful, remove tracheostomy tube and exchange if possible
After tracheostomy tube removed, it might be possible to ventilate lungs by sealing stoma and using bag-valve applied to face or intubating orally (may not be possible if there was originally significant upper airway obstruction)
What to do when choking
Assess for signs of severe or mild airway obstruction
If mild, encourage to continue coughing
If severe, 5 back blows, (check each has resolved choking)
If fails, give abdominal thrusts
How do you give back blows
Stand slightly to side of patient and behind
Support chest with one hand, lean patient forward, 5 blows sharply between scapulae with other hand
How to give abdominal thrusts
Behind patient, arms around upper part of abdo, clenched fist under xiphisternum, pull sharply inwards and upwards
Repeat 5 times
Then alternate between back blows and abdo thrusts
How do you do a jaw thrust
Place index finger and other fingers behind angle of mandible, apply steady upwards and forward pressures to lift it
Also use thumbs to slightly open mouth and displace chin downwards
How do size an oropharyngeal airway
If in doubt put a bigger one in
Vertical distance between incisors and angle of jaw
Risk of oropharyngeal insertion
Tongue can be pushed backwards and obstruct further
How to insert an OPA
Insert backwards, advance until you hit junction of hard-soft palate then rotate 180 with advancement
What should you check for before an OPA insertion
Ensure no foreign bodies are there
What contraindicated an NPA
Basal skull fracture
What size should you use for an NPA
6-7mm (don’t go too big)
Traditional sizing unreliable
What FiO2 can a non-rebreather mask deliver at flow rates of 10Lmin-1
85%
What max FiO2 can a simple face mask deliver
50%
What max FiO2 can a self inflating (bag-valve) bag and mask give
85%
What FiO2 can a self inflating bag give if no oxygen or reservoir system attached?
21%
Risks of over inflation using bag valve mask
Gastric inflation and regurgitation that could lead to aspiration
What size is usually best for i-Gel SGA
Size 4
Limitations of iGel
Risk of significant leak in high airway resistance or poor lung compliance
Uninterrupted chest compressions can cause some gas leak- if evidenced, should do 30:2 instead
Theoretical aspiration risk
If not unconscious, coughing, straining, laryngeal spasm possible
What forms of syncope do not warrant admission
Situational (micturition, cough syncope)
Orthostatic hypotension
Uncomplicated faints
Which lead is best to see p waves
Lead II and V1
Which leads are best to spot atrial flutter
Inferior leads
II, III, aVF
What rate would atrial activity usually go at for atrial flutter
Around 300bpm
In atrial fibrillation what happens to p waves
You can’t see them but you can also see fibrillatory waves V1 where there is varying amplitude and duration of p waves
What would you see in retrograde activation of atria from the AV node?
Inverted p waves in leads II and aVF
What do you suspect if there is AF accompanied by a completely regular ventricular rhythm with a slow rate?
AV block
What two rhythm abnormalities can resemble VF?
- polymorphic VT
- pre-excitation syndromes such as WPW (which mimics polymorphic VT)
What happens when p waves are conducted to ventricles in VT?
Fusion or capture beats occur
What are fusion or capture beats?
P waves in VT that conduct to ventricles
Capture beat: normal looking QRS complex
Fusion beat: hybrid QRS caused by fusion of normal QRS from AV node with activity coming from ventricular focus causing VT
What should be avoided in Torsades de Pointes?
Drugs prolonging QTc, including amiodarone
In CHB, what determines the rate and QRS width?
The ventricle- stimulating pacemaker site:
- if in AV node or proximal bundle of His, intrinsic rate of 40-50 bpm or higher possible with narrow QRS
- if in distal His-Purkinje fibres or ventricular myocardium, rate 30-40 bpm or less with broad QRS (*more dangerous with greater likelihood of arrest and asystole)
What is an idioventricular rhythm?
Rhythm rising from ventricular myocardium, including ventricular escape rhythms from CHB.
Accelerated idioventricular rhythms have normal HR, observed often after successful thrombolyses or PCI (reperfusion arrhythmia) - these are not too worrying unless VT/VF develops
What are escape rhythms?
Cardiac depolarisation being initiated from subsidiary ‘pacemakers’, not the SA node
In escape rhythms, as a general rule, what influences the rate?
Location of pacemaker - distal more slow, proximal faster (ventricular escape rhythms slower than junctions rhythm from AV node or bundle of His)
What is an agonal rhythm?
Occurs in dying patients, slow, irregular, wide ventricular complexes of varying morphology
Becomes progressively broader before progressing to asystole
What is the anatomical threshold for a rhythm to be supraventricular?
Origin superior to bundle of His
Some causes of A Fib
HTN, Obesity, ETOH excess, Structural heart disease, hyperthyroid, LV impairment (acute or chronic, not usually due to direct ischaemia of atrial myocardium)
Causes of A Flutter
Usually right atrial issues, so from RHF related things, eg COPD, large PEs, congenital heart disease, CCF
Normal ranges of QTc
Up to 0.45s in men
Up to 0.47s in women
What QTc indicates high risk of cardiac arrest and sudden death?
0.5s or longer