Cardiac Arrest (AMI) Flashcards
Cardiac Arrest (def.)
A clinical diagnosis that means effective cessation of the heart.
No circulation means no oxygen delivery.
ABC of patient with cardiac arrest.
Unresponsive patient
Not breathing properly
No pulse
OHCA vs. IHCA presenting rhythm
Presenting rhythm in OHCA is usually VF/VT aka shockable. Most IHCA non-VF/VT aka non-shockable.
What is the main problem with cardiac arrest?
+survival rates
Poor outcomes despite treatment.
Survival to leave hospital:
OHCA- 8%
IHCA- 18.4%
DO2 =
SaO2 x [Hb] x O2cc x CO (HR x SV)
[O2cc = oxygen carrying capacity of haemoglobin, approx 1.36ml O2/g Hb]
Overview of route of oxygen delivery.
Inhalation by nostrils Nasopharynx Oral pharynx Glottis Trachea Bronchus (right and left) Bronchioles Alveoli Blood Heart Systemic Circulation
Why are most cardiac arrests predictable?
Prior deterioration in 50-80% of cases- hypoxia and hypotension common.
Core Standards in all settings
- Deterioration recognised early with effective help system to prevent arrest
- Arrest recognised early and CPR started immediately
- Help summoned as soon as arrest is recognised (if not already)
- Defibrillation, if appropriate, within three minutes of arrest where achievable
- Appropriate post-arrest care is resuscitated, including safe transfer
- Standards measured continually and identified problems dealt with
- At least annual training and updates in CPR
- Appropriate equipment available for resuscitation
Early recognition prevents…
Cardiac arrests and resulting deaths
Admissions to ICU
Inappropriate resuscitation attempts.
What is the “golden hour”?
concept of urgency, one hour after a trauma/event is the best time to treat.
Cardiorespiratory Arrest (def.)
No pulse, no breathing.
How can oxygen delivery factors be improved?
SaO2 - ↑FiO2, clear airway, adequate breathing
[Hb] - transfusion trigger, treat anaemia - Gp&S / X-match, IV access, (Fe etc)
Heart Rate - atropine or β-stimulant (e.g. ephedrine) for bradycardia
BP - preload (IV fluids, raise legs), contractility (treat cause e.g. PCI for MI), afterload.
(remember- golden hour concept)
6 Physiological Parameters of NEWS
Respiratory Rate Oxygen Saturations Temperature Systolic BP Pulse Rate Level of consciousness
How are oxygen delivery factors assessed?
SaO2 - clinical (not reliable), pulse oximetry, arterial blood gas (gold standard)
[Hb] - clinical (not reliable), part of full blood count, bedside (e.g. hemocue)
Heart rate - pulse, pulse oximetry, ECG monitor (with sound), arterial BP monitor
BP - use equation BP = CO x TPR. Once HR accounted for, BP determined by SV and/or TPR. SV depends of preload, contractility and afterload. BP always due to HR, preload, contractility or afterload change. Use clinical info to determine which).
Causes of airway obstruction
CNS depression- tongue
Lumen blocked- blood, vomit, foreign body
Swelling- traume, infection, inflammation
Muscle- laryngospasm, bronchospasm
How would you recognise airway obstruction?
Talking
Difficulty breathing, distressed or choking
SOC
Noisy breathing- stridor, wheeze, gurgling
Seesaw respiratory pattern, accessory muscles
How would you treat airway obstruction?
- Airway opening- head tilt, chin lift, jaw thrust, suction
- Simple adjuncts
Advanced techniques e.g. LMA, tracheal tube - Oxygen (increase FiO2)
Causes of breathing problems
Airway problems
Decreased resp drive (CNS depression)
Decreased resp effort (muscle weakness, nerve damage restrictive chest defect, pain from fracture ribs)
Lung disorders (pneumothorax, haemothorax, infection, COPD, asthma, PE, ARDS
How would you recognise a breathing problem?
LOOK- resp distress, accessory muscles, cyanosis, RR, chest deformity, consciousness.
LISTEN- noisy breathing, breathing sounds
FEEL- expansion, percussion, tracheal deviation
How would you treat breathing issue?
- Airway
- Oxygen
- Treat underlying cause e.g. drain pneumothorax
- Support breathing if inadequate
Causes of circulation problems (primary and secondary)
Primary: ACS Dysrhythmias Hypertensive heart diseases Valve disease Drugs Hereditary cardiac diseases Electrolyte/acid base abnormalities Electrocution
Secondary Asphysxia Hypoxaemia Blood loss Hypothermia Septic shock
How would you recognise a circulatory problem?
General examination- distress, pallor, etc.
Pulse- tachy/brady
BP
Peripheral perfusion- capillary refill time
Indicators of organ perfusion- chest pain, mental state, urine output
Bleeding, fluid losses
How would you treat a circulatory problem?
- Ensure airway, breathing and oxygen
- Cannula for taking blood, plus IV/IO access
- Treat the cause- fluid challenge, inotropes/vasopressors, MONAC for ACS
- Haemodynamic monitoring
How would you recognise/assess ‘disability’?
AVPU or GCS (+pupils)
How would you treat ‘disability’?
Treat underlying cause.
Check blood glucose- if < 3 mmol/l, give glucose
Consider lateral recovery position
Check drug chart
E = Exposure. How is this dealt with?
Remove clothing to enable thorough examination, to avoid missing the causes or problems, e.g. injury, bleeding, rashes. However, it is important to avoid heat loss and maintain patient dignity.