Adult ALS

Introduction

• The importance of BLS
  • Effective chest compression provides 20-30% of pre-arrest cardiac output
  • Rescue breathing without supplemental oxygen provides FiO2 of 0.15
  • May increase likelihood of successful defibrillation
  • Buys time until reversible causes can be diagnosed and/or treated
• Attempts to secure airway should occur with <5 seconds interruptions to chest compressions
• Once secured airway (SGA or ETT), provide ventilations at 6-10/min without interruptions to CPR Iin decompression phase)
• Defibrillation shocks should be provided as soon as defibrillator available
• Pause chest compressions <5 seconds to assess rhythm prior to defibrillation
• Re-start chest compressions as soon as shock provided (do not check rhythm again)

Bystander CPR

• Witnessed in 50%
• Bystander CPR in 20-50% of cases
• Improves survival rates
  • 10% decrease in survival/min without CPR
  • 4% decrease in survival/min with CPR

Survival after cardiac arrest

• Gasping respiration when found
  • Present in 10% of cardiac arrest
  • 20% chance of survival with good neurological outcome if present vs. 4% if not present
• 85% of survivors are able to live independently
• Full functional recovery takes 6-12 months

Time to CPR and Defib

• CPR <3 min and ALS < 6 min = 70% survivors from VF
• CPR >3 min and ALS > 6 min = 40%
• In primary cardiac arrest
  • Long-term survival not expected after 8 minutes
  • CPR extends this to 12 minutes
  • Defib must be delivered within 12 minutes to alter outcome

Location

• OOHCA
  • 35% survive to hospital arrival
    • 70% in best systems
    • 15% for VF and 2% for asystole
  • Survival to hospital discharge
    • 5-15% in total
    • Up to 20% in good systems
    • 10-35% for VT/VF
    • 5-10% for PEA
    • 1-10% for asystole
    • 15% for witnessed VF/VT
  • OOHCA better outcomes than inpatient
  • MET teams not proven to reduce incidence of cardiac arrest, unplanned ICU admissions or unplanned deaths
• Critical care areas
  • 70% survival in CCU/ED
  • Lower in ICU likely due to severe underlying illness

Prognostic

• Hypotension following arrest
  • Associated with higher mortality (85% vs. 60%)
• Echo
  • Absence of cardiac activity has <5% probability of ROSC
  • Presence of cardiac activity has 80% chance of ROSC

Prevention

• Prevention of cardiac arrest
  • Children and young adults who present with possible arrhythmic syncope should have specialist cardiology review, ECG and in most cases an echo and stress test
  • This includes:
    • Syncope in supine position
    • Syncope during or after exercise
    • Syncope with no or only brief prodromal symptoms
    • Repetitive episodes
    • Syncope with FHx of sudden cardiac death
  • Non-pleuritic chest pain, palpitations with syncope, seizures (when resistant to treatment or occurring at night) should all raise suspicion of arrhythmogenic syncope

CPR Physiology

• Each compresses increases right heart pressure causing forward flow due to one-way cardiac valves and intrathoracic pressure > extrathoracic pressure
• High intrathoracic pressure is transmitted to cerebrum to cause raised ICP limiting cerebral perfusion
• Raised right heart pressures with each compression limit coronary flow by same mechanism
• Decompression phase
  • Heart refilled passively and vacuum effect
  • Less effective is chest recoil is poor i.e. broken ribs
  • Reduces ICP simultaneously by same pressure transduction which in turn increases cerebral perfusion pressure

• Gasping
  • May occur if brainstem perfusion is sufficient to trigger resp centre
  • Results in negative intrathoracic pressure, vacuum effect on venous circulation, inspiration of air and reduced ICP to increase cerebral perfusion
• Coughing
  • Inspiratory phase same as above
  • Coughing phase
    • Intrathoracic pressure increases prior to opening of glottis
  • Cough CPR has been shown to maintain perfusion in VF for many minutes

• ACD-CPR
  • Active compression decompression CPR
  • Pushes down and pulls up on chest to generate both positive and negative intrathoracic pressure
  • Increases coronary and cerebral perfusion but no proven outcome benefit
• Inspiratory impedence threshold device
  • Prevents inspiratory PPV during recoil phase to improve venous return and coronary/cerebral perfusion
  • Proven to reduce intrathoracic pressure and improve perfusion but no proven outcome benefit
  • Combined with active compression/decompression device shown to improve ROSC but NOT long-term survival

• Head up CPR
  • Elevation of head may improve cerebral perfusion and improved venous return to heart from head
  • Head down increases ICP and reduces cerebral perfusion dramatically
  • In animal studies, only beneficial if impedence threshold device is used  Removal led to reduced coronary and cerebral perfusion with raised ICP immediately
• Interposed abdominal compression CPR
  • Additional compression midway between xiphoid and umbilicus 
  • Use in-hospital is supported by literature but not OOHCA
  • Improves venous return during recoil phase

• Phased thoracic-abdominal compression-decompression (PTACD)
  • Combines interposed abdominal compressions with active compression-decompression technique

Pad position

• Pad position
  • Left midaxillary line 6^th ICS and right parasternal area 2^nd ICS
• Risks
  • Ensure good contact and pads not touching one another
  • Avoid oxygen flow over chest during defibrillation

Adjuct airways

• Nasopharyngeal airways
  • No published data on use in resuscitation
  • Recommended if no evidence of base of skull #
• Oropharyngeal airways
  • Reserved for unconscious, obtunded patients
  • No evidence of benefit but still recommended to allow bag-mask ventilation
• Advanced airways
  • Insufficient data to recommend one over another
  • States ‘to avoid substantial interruptions to compressions, providers may defer attempts to insert devices/adjuncts until ROSC’
  • Also states ‘supraglottic airways may result in shorter interruptions to compressions as compared to ETT’
  • Laryngoscopy, if performed, should occur during chest compressions
  • SGA and ETT frequently used in stepwise manner throughout resuscitation with view to minimising interruptions until ROSC

Adult ALS

• Stacked shocks
  • Recommended if:
    • Witnessed and monitored
    • Defibrillation possible within 20 seconds
  • Without commencing chest compressions checking for rhythm change and pulse briefly between shocks
• Praecordial thump
  • Can attempt praecordial thump in pVT if delay in defib attachment but rarely successful
  • Praecordial thump not recommended for VF
  • Hold clenched fist 25-30cm above sternum
• Percussion (fist) pacing is not recommended but can consider in bradyarrhythmias until electrical pacemaker becomes available

• Studies show ALS providers perform inadequate depth compressions, excessive ventilations and excessive pauses in compressions
• Checking for pulse
  • If trained in doing so, can check for central pulse while assessing for signs of life but if any question, just start CPR
• Need to avoid simultaneous ventilation and compression once secured airway in place (may adversely affect coronary perfusion and survival)

Open chest CPR

• Better cardiac output (2/3 normal and near-normal coronary perfusion achievable)
• Strongest indication is for reversible pump failure e.g. beta-blocker/CCB toxicity
• No improvement in outcome if instituted after >20 minutes of CPR
• May improve initial resuscitation but not survival
• Left lateral thoracotomy, leaving pericardium closed
• Always use two hands (one hand risks RV/RA damage)

etCO2

• To monitor and guide cardiac arrest therapy
• Correlates in animal studies with cardiac output, coronary perfusion pressure and ROSC
• etCO2 <10 obtained after intubation or 20 min of CPR are associated with low probability of survival
  • Should not be used as a sole predictor of survival in decision-making
• etCO2 >10 after intubation or 20 min of CPR may be an predictor of ROSC
• etCO2 >20 after intubation or 20 min of CPR may be an predictor of survival to discharge
• May be early indicator of ROSC if shoots up (sudden increase >10mmHg is 95% specific for ROSC)
• Should not be used as a guide to ventilation during and immediately after resuscitation
• Mean incidence of unrecognised oesophageal intubation in cardiac arrest is 4.3%

ABG

• May be considered during resuscitation as estimates degree of hypoxaemia and adequacy of ventilation
• Not a reliable indicator of extent of tissue acidosis
• Low PaCO2 indicates excessive ventilation
• High PaCO2 may have to be tolerated due to risks of increasing ventilation rate/tidal volume on coronary perfusion
• Also may assist in electrolyte checking

Realtime feedback devices

• May be helpful but can overestimate compression depth on soft beds
• May be considered as part of an overall attempt to improve system-wide CPR quality
• No high level evidence of improved outcomes

Ventilation after ROSC

• Reasonable to start at 12/min until PaCO2 can be measured

Defibrillation

• Energy levels
  • 200J initially and can increase to maximum available if initial shock fails
  • 360J monophasic if biphasic not available
• Biphasic vs. monophasic
  • Biphasic shown to improve successful defibrillation in prolonged VF/VT, lower energies but no improvement in neurologically intact survival

PEA

• PEA
  • 50% due to primary cardiac event
  • 30% of survivors have acute coronary occlusions
  • Higher incidence in those with underlying pulmonary disease, women and older age
  • Causes
    • Pericardial tamponade (myocardial wall rupture, type A dissection, traumatic), tension PTX, massive PE, hypovolaemia, severe acidosis (<6.9), drug toxicity, electrolyte disturbance
• Up to 35% of ‘asystole’ is actually PEA if US pulse check used

Medications during CPR

• Vasopressors
  • Evidence of increased ROSC but NOT survival to hospital discharge
  • Adrenaline 1mg after 2^nd failed shock then every 2 cycles (4 min)
• Antiarrhythmics
  • No evidence of improved survival to hospital discharge
  • Survival to hospital admission improved with amiodarone as compared to lignocaine or placebo
  • ALPS study showed no benefit of amiodarone or lignocaine compared to each other or placebo in achieving survival to discharge or neurological outcome in OOHCA
  • Amiodarone 300mg after third failed defibrillation attempt +- 150mg second bolus +- 15mg/kg over 24 hour infusion
  • Lignocaine can be used as an alternative 1mg/kg bolus +- 0.5mg/kg second bolus
• Other drugs
  • No evidence for any other drugs in improving survival to hospital discharge (e.g. bicarb, aminophylline, atropine, calcium, magnesium)
  • May be used to treat specific underlying conditions
• Adrenaline, lignocaine and atropine can all be given via ET if no IV/IO access. Other drugs CANNOT.

• Vasopressin
  • OOHCA
    • Vasopressin vs. adrenaline showed higher survival in asystolic patients (Wenzel et al.)
    • Not accepted by ARC
  • IHCA
    • No benefit over adrenaline in small trials
    • Anecdotal success when adrenaline has failed
    • Greek study showed combination vasopression + adrenaline + methylped vs. adrenaline alone had higher ROSC and survival to hospital discharge
    • Not in ARC guidelines

• Medications continued
  • Magnesium 5mmol bolus then infusion 20mmol over 4 hours if required
  • Potassium 5mmol bolus
  • Sodium bicarbonate
    • Considered for hyperkalaemia, treatment of severe metabolic acidosis, TCA overdose, protracted arrest >15 min
    • 1mmol/kg over 2-3 min then guided by blood gases

USS during arrest

• Absence of any cardiac motion is highly predictive of death
• If available and can be performed without significant interruption, may be utilised to identify reversible causes of cardiac arrest

POCUS for PE

• Right ventricular enlargement (RV > LV) (may be chronic though) – normal 0.6:1
  • Sensirtivity 50%; Specificifity 98%; PPV 88%
• RV systolic dysfunction (hypokinesis)
• McConnell’s sign – mid RV wall hypokinesis with apical sparing
  • 100% specific in one study
• Moderate to severe TR
• Paradoxical septal wall motion towards LV
• Pulmonary artery dilatation
• Atrial dilatation
• Right heart thrombus
• Lack of respiratory variation in IVC
• In haemodynamic instability, RV strain on POCUS is very specific for PE

Advanced techniques

• Impedence threshold device (ITD)
  • NO clinical benefit and advised against routine use
• Automated mechanical chest compression devices (ACT’s)
  • Advised against routine use
  • Are a reasonable alternative to manual compressions if sustained high-quality manual compressions are impractical or compromise rescuer safety
  • May increase survival to hospital discharge in prolonged arrests (>10 min CPR)
  • Increases ROSC by 10% but not shown to improve longer term outcomes

• Extracorporeal CPR (eCPR)
  • Reasonable rescue therapy if standard CPR is failing
  • For IHCA – 2 observational studies showing improved neurological survival at 130 days but not at 1 year; improved survival at 30 and 180 days but not 1 year; improved outcome at hospital discharge
  • For OHCA – 2 observational studies showed improved functional survival at 30, 90 and 180 days
• Open chest CPR
  • Consider for patients early post-operatively or when chest/abdomen open following trauma or for penetrating chest trauma
  • Improves outcomes in these groups
  • Can consider for cardiac arrest caused by hypothermia, PE, pericardial tamponade, abdominal haemorrhage, penetrating abdominal trauma with witnessed deterioration or blunt trauma with cardiac arrest

Targeted oxygen therapy

• Supplemental oxygen indicated if SpO2 <94% and requiring ALS
• 100% O2 during cardiac arrest recommended
• After ROSC, target 94-98%
• 100% O2 should be continued for CO poisoning
• 100% O2 should be continued for decompression illness
• In paraquat poisoning or bleomycin-induced lung injury, target SpO2 88-92%
• In patients at risk of hypercapnoeic respiratory failure, target 88-92%
  • Includes over 50yo long term smokers with chronic hx of breathlessness on minor exertion without other known cause
  • COAD
  • CF, bronchiectasis, severe kyphoscoliosis/Ankylosing spondylitis, BMI >40, MSK disorders with respiratory muscle weakness and respiratory depressant medications

Reversible causes

• 4H’s and 4 T’s
  • Hypoxia
  • Hypo/hyperthermia
  • Hypo/hyper-electrolytes
  • Hypotension/hypovolaemia
  • Toxins – Poisons or drugs
  • Thrombosis – Coronary or pulmonary
  • Tamponade
  • Tension pneumothorax

• Fluid administration – Recommended crystalloid boluses if hypovolaemia suspected
• Thrombolytics
  • Routine administration of in- or out-of-hospital cardiac arrest not recommended as no evidence of benefit
  • Consider in adults with proven or suspected PE
  • If given, continue CPR for 60-90 min before termination of resuscitation attempts
  • PE may be responsible for 8-13% of unexplained cardiac arrests
  • Coronary disease also may benefit from thrombolysis
  • 19% survival vs. 9% for thrombolytics in massive PE generally
  • Triad to suggest PE = Witnessed arrest, age <65 and PEA initial rhythm (50% had PE in Courtney et al.
  • Other factors that increase likelihood include:
    • Unilateral leg swelling, active cancer, revent long-haul travel, orthopaedic surgery/immobilisation, SpO2 <95%
    • Medical history of previous VTE and clotting disorders also increased risk

Contraindications to CPR

• Unsuccessful appropriately performed pre-hospital ACLS
• Known terminal illness not immediately post-op
• Obviously unsurvivable injuries
• Valid AHD
• Situation puts rescuers at risk

Pre-hospital termination of CPR

• Appropriate if all of:
  • Non-witnessed arrest
  • No bystander CPR
  • No prehospital defibrillation
  • No ROSC
• None of the above patients will survive to discharge

CPR in the elderly

• Relatively contraindicated due to low survival rates
  • 7% in 70-79 yo
  • 3% in >80yo

Post-arrest care

• Aims
  • Continue respiratory support
  • Maintain cerebral perfusion
  • Treat and prevent cardiac arrhythmias
  • Determine and treat the cause of arrest
• Airway and breathing
  • Maintain SpO2 94-98%
  • Advanced airway or conversion from supraglottic to ETT
  • Waveform capnography, ventilate to normocapnoea

• BP
  • Aim for usual BP or at least SBP >100
  • 12-lead ECG
  • Restore normovolaemia
  • IABP
  • Consider inotrope/vasopressors
• Control temperature
  • 32-36 degrees and treat fever/shivering
• Blood glucose control
  • Good evidence that persistent hyperglycaemia is associated with poor outcomes post-arrest and stroke
  • No survival benefit with strict control (4-6) vs. moderate (6-8)
  • Monitor frequently and treat hyperglycaemia >10 with insulin while avoiding hypoglycaemia

• Prophylactic antiarrhythmics
  • Reasonable to continue infusion of antiarrhythmic that successfully restored stable rhythm (lignocaine 2-4mg/min or amiodarone 0.6mg/kg/hr for 12-24 hours (15mg/kg over 24 hours)
  • Can consider use to prevent recurrent VF even if not used in resuscitation
  • 25% of arrest survivors have BBB (60-90% resolve within 4-48 hours)
• Temperature control
  • Shown to be of benefit in patients who remain comatose after ROSC
  • Targeted temperature management 32-36 degrees for all patients comatose after ROSC
  • Reasonable to assume non-cardiac causes may also benefit from this
  • Rapid ice-cold IV fluids up to 30mL/kg and ice packs are reasonable means of reducing core temp by 1.5 degrees
  • Not recommended pre-hospital
  • Duration should be at least 24 hours if used
  • PCI during TTM is safe and recommended
  • Suggest prevention and treatment of fever even after TTM completed
  • TTM study showed no difference between 33 and 36 degree targets over 36 hours

• Sedation and paralysis
  • No evidence for any specific regime
• Seizure control
  • 3-44% risk of seizures after ROSC
  • Routine prophylactic anticonvulsants not recommended
  • Treat seizures aggressively if they do occur
  • Maintenance therapy to prevent seizures should be started after the first event and look for underlying cause

• Resuscitation-related injuries
  • Recommended to evaluate for any injuries, change any dirty lines and check lines/tubes

• TTM (normothermia target)
  • Bradycardia with cooling is very common (but rarely of significance)
  • Tachydysrhythmias are rare unless <32 degrees
  • Shivering is common and may limit cooling and can be treated with NM blockers
  • Bleeding may be exacerbated by cooler temperatures
  • Hypokalaemia and cold-mediated diuresis are common
  • Hypotension in rewarming phase
• Head CT in survivors as soon as possible (may identify subarachnoid, subdural, epidural or cerebral oedema)
  • 10% incidence in ICH in survivors of OOHCA in one series 
  • Only 10% of these survived and none had good neurological outcome

Post-ROSC PCI

• Coma should not be a contraindication to immediate PCI if indicated
  • 60% survival and 85% good neurological outcome despite coma
• Class I recommendation for STEMI to go to cath lab (AHA/ACCF)Consider benefit/risk ratio if multiple unfavourable risk factors
  • If STEMI before or after arrest or new LBBB, immediate angiography recommended
• ECG changes of STEMI absent in 25-40% of those with acute coronary occlusion post-arrest
• TTM recommended in concert with primary PCI
• Observational studies have shown acute coronary occlusion present in 80% of post-arrest patients >45yo and 25-35% if no STEMI features present

• COACT trial
  • Lemkes et al. 2019
  • Randomised open-label trial to compare a strategy of immediate coronary angiography with delayed angiography in patients who have been successfully resuscitated after cardiac arrest without STEMI on ECG
  • Patient had to have initial shockable rhythms and remain unconscious after ROSC
  • Patients were excluded if they had STEMI on ECG, shock or an obvious noncardiac cause of arrest
  • Primary endpoint was survival at 90 days
  • 538 patients underwent randomisation
  • Acute unstable lesions were identified in 13.6% of immediate group and 16.9% of delayed group
  • Acute thrombotic occlusion was found in 3.4% of the immediate-angiography cohort and 7.6% of the delayed cohort
  • PCI was performed in 33% of patients in the immediate angiography group and 24.2% of the delayed group
  • 64.5% of patients in the immediatre group survived to 90 days vs. 67.2% in the delayed group (P=0.51)
  • This differs from previous observational studies
• TOMAHAWK Trial (Desch et al. 2021)
  • COACT only included those with shockable rhythm while TOMAHAWK assessed the same premise in all OOHCA without STEMI
  • Randomised, open-label study comparing immediate vs. delayed angiography
  • Patients at least 30 years old were eligible
  • Primary endpoint was death from any cause at 30 days
  • 554 patients were randomised
  • Rates of suspected culprit lesions, coronary artery disease and revascularisation were similar between groups
  • Primary endpoint of death from any cause at 30 days in 54% of immediate group and 46% in the delayed group (not significant)
  • No significant difference in time to event analysis

• If non-STEMI
  • Assess for unfavourable risk factors
  • Consult with Cardiology
  • Transport for early angiography if decision made to perform
  • Observational data suggests ¼ of these will have acute occlusion and 60% will have significant obstructive lesion

• Favourable resus features
  • Witnessed
  • Early CPR
  • Short-time to ROSc
  • Good perfusion
  • Age < 85

• Unfavourable risk factors
  • Unwitnessed arrest
  • Initial non-VF rhythm
  • No bystander CPR
  • >30 min to ROSC
  • Ongoing CPR
  • pH <7.2
  • Lactate >7
  • Age >85
  • End-stage renal disease
  • Non-cardiac cause evident

Post-resuscitation syndrome

• Ischaemia-reperfusion injury
  • Mitochondrial injury, increased oxygen free radicals, programmed cell death
  • Immune activation
  • Sepsis-like syndrome
  • Brain tissue and vascular endothelium are particularly vulnerable
• Organ system effects
  • Vascular leak
  • Drop in PVR
  • Hypotension
  • Cerebral oedema
  • Raised ICP
  • Myocardial stunning (usually for a few days only)
  • Increased risk of infection possibly secondary to bacterial translocation across ischaemic intestinal cells
  • Adrenal insufficiency due to ischaemia

• Post-cardiac arrest syndrome
  • Post-cardiac arrest brain injury
    • Coma, seizures, myoclonus, neurocognitive dysfunction and brain death
  • Myocardial dysfunction
    • Accounts for most deaths in first 3 days and lasts about this long
  • Ischaemia/reperfusion response
    • Immune and coagulopathy –> MODS
  • Persistent precipitating pathology

Prognosis

• Multimodal assessments should be performed and supplementary tests considered in context of clinical information
• Different recommendations for hypothermic TTM and normothermic TTM
  • Hypothermic patients have slower neurological recovery, large doses of sedatives/paralytics and slow metabolism of these medications
• Findings recommended if false positive rate <5% for poor neurological outcome and deemed useful if <10%
• Relying on neurological examination during cardiac arrest is NOT recommended
• Recommend against use of clinical criteria before 72 hours after ROSC
• Recommend using absence of pupillary light reactivity (or combined absence of both light and corneal reflexes) at 72 hours post-ROSC to predict poor outcome
• Suggest against use of M1 or M2 score on GCS as prognostic indicator
• Suggest using myoclonus in concert with other clinical findings as a prognostic indicator of poor outcome
• Suggest prolonging period of observation if sedation/paralytics suspected to still be on board

• Electrophysiology
  • Recommends using bilateral absence of N20 SSEP wave within 72 hours to predict poor outcome
  • Suggest using burst suppression at 72 hours in combination
  • Suggest against using EEG grades
  • Suggest against low-voltage EEG and BIS
• Blood markers
  • High serum values of NSE at 24-72 hours in combination with other clinical factors over multiple times can help predict poor outcome (not perfect)
• Imaging
  • Suggest using marked reduction in GM/WM ratio on CT within 48 hours or extensive reduction in brain diffusion on MRI at 2-6 days post-ROSC

Managing acute dysrhythmias

• Bradyarrhythmia
  • Adverse signs that suggest immediate therapy required
    • SBP <90
    • HR <40
    • Ventricular arrhythmia
    • Heart failure
  • Drug therapy
    • Atropine 500-600mcg q3-5min up to total dose 3mg
    • Low-dose adrenaline is second-line agent (bolus or infusion)
      • 2-10mcg/min targeting stable heart rate and MAP of 70
    • Isoprenaline 2-5mcg/min
    • Dopamine 2-5mcg/kg/min
    • Theophylline
    • Glycopyrrolate
    • In the presence of beta-blockers/CCB will require much higher doses and consideration of glucagon or HIET
    • Do not give atropine in cardiac transplant patients as heart is denervated and some risk of inducing paradoxical AV block exists (ANZCOR)
  • Pacing
    • Risk of asystole indicated by presence of any of:
    • Recent asystole
    • Mobitz II AV block
    • Complete heart block (esp. with broad QRS or HR <40)
    • Ventricular standstill >3 seconds
    • Start at synchronised 70-80/min with 30mA increasing by 10mA until complete capture then go 10% higher
    • Ventricular electrical capture confirmed by each pacing spike followed by QRS and T wave in opposite direction
    • Do not confuse after-potential for evidence of capture (wide, slurred complex)
    • Recommended to increase current to 10% above initial threshold for electrical capture
    • Mechanical capture confirmed by arterial pulse equal to pacing rate

• Tachyarrhythmia
  • 80% of cardiac arrests due to tachyarrhythmia
  • Adverse features that suggest immediate therapy required
    • SBP <90
    • HR >150
    • Chest pain
    • Heart failure
    • Drowsiness or confusion
  • If peri-arrest/deteriorating attempt synchronised DC cardioversion first with sedation, then consider amiodarone 300mg over 10-20min, then repeat cardioversion. Follow with amiodarone 900mg over 24 hours (15mg/kg)

ALS 

• Of ambulatory ECG monitored OOHCA
  • 70% VT and VF
  • 13% TdeP
  • 17% bradyarrhythmias
• Untreated VF deteriorates to asystole within 15 minutes
• Following cardiac arrest, rate of survival drops by 7-10% each minute without defibrillation
• If delay to defibrillation exceeds 12 minutes, survival is 0-5%

Arrhythmia management

• Regular broad-complex tachycardia
  • In absence of adverse features:
    • Amiodarone 300mg over 20-60min, then 900mg over 24 hours (15mg/kg)
  • Consider beta-blockade if hyperadrenergic cardiomyopathy or VF storm
• Irregular broad-complex tachycardia (AF with BBB, AF with WPW, torsades de pointes)
  • Electrical cardioversion is safest option
  • Procainamide, flecainide are other options
  • Avoid adenosine, digoxin, verapamil, diltiazem and beta-blockers if possible pre-excitation
• Torsades de pointes
  • Stop all QT prolonging agents, treat hypokalaemia and give MgSo4 5mmol over 10 min, can repeat once and then infusion 20mmol over 4 hours
  • If torsades due to heart block, symptomatic bradycardia or pause dependence, may require overdrive pacing, beta-blockade and pacing or isoprenaline +- cardioversion. Avoid amiodarone as makes situation worse. Seek expert help in this situation

• Regular narrow-complex tachycardia
  • Sinus tachycardia, AVnRT, AVRT, A flutter
  • If unstable, synchronised DC cardioversion
  • Can attempt adenosine while preparing for cardioversion
  • In the absence of adverse features, start with Valsalva, then adenosine if deemed not flutter, 6/12/12 with 20mL flushes
    • Analyse rhythm after adenosine to determine if flutter waves present
  • Verapamil 2.5-5mg IV over 2 min or diltiazem 15-20mg over 2 min third-line
  • Beta-blockers can also be considered

• Irregular narrow-complex arrhythmia
  • AF or flutter with variable AV conduction
  • Unstable – synchronised DC cardioversion with sedation
  • Stable
    • Oral or IV beta-blocker rate control
    • CCB if bronchospasm history
    • Digoxin 250-500mcg IV or PO if heart failure or sedentary
    • Can consider amiodarone for rate control if above ineffective or CI
    • Can use amiodarone if accessory pathway evident
    • IV digoxin, beta-blockers or CCB to patients with AF and pre-excitation may accelerate the ventricular response

Special circumstances

• Of OOHCA, 30% thought to be non-cardiac
• Typically young with no co-existing cardiac disease
• Anaphylaxis
  • Adrenaline
    • IM 0.5mg if >12yo
    • IM 0,3mg if 6-12yo
    • IM 0.15mg if <6yo
  • IV adrenaline if fails – adult 50mcg boluses; children 1mcg/kg then infusion 2-10mcg/min in adults
  • Large volume resuscitation
  • Prolonged resuscitation may be necessary
  • Hydrocortisone
    • 200mg IM or slow IV if >12yo
    • 100mg if 6-12yo
    • 50mg ig 6 months to 6 years 
    • 25mg if <6mo

• Asthma
  • Linked to severe bronchospasm and asphyxia, cardiac arrhythmias (beta-agonists, hypoxia, electrolyte disturbance), dynamic hyperinflation and tension pneumothorax (often bilateral)
  • Early intubation should be considered as ventilation is often difficult
  • If dynamic hyperinflation is suspected, disconnection and compression of chest wall may assist and consider co-existent anaphylaxis
• Avalanches
  • Not likely to survive if:
    • Buried >35 min and in cardiac arrest with obstructed airway on extrication
    • Buried initially and in cardiac arrest with obstructed airway on extrication and initial temp <32 degrees
    • Buried initially and in cardiac arrest on extrication with initial serum potassium >12mmol

• Cardiac surgery
  • 0.7-2.9% immediately post-operative cardiac arrest rate
  • Survival to discharge after cardiac arrest during first 24 hours is 54-79% in adults and 41% in children
  • Main causes
    • Cardiac tamponade
    • Myocardial ischaemia
    • Haemorrhage causing hypovolaemic shock
    • Disconnection of pacing system
    • Tension PTX
    • Electrolyte disturbance (particularly K)
  • Adverse effects of cardiac compressions may be more significant so early defib is particularly important
  • 3 stacked shocks is recommended for any shockable rhythm post-cardiac surgery to minimise compression-related complications BUT only if defib available within 20 seconds
  • If brady-asystolic arrest in setting of epicardial wires have been previously attached, use them for pacing (fixed ventricular pacing)
  • Re-sternotomy allows visualisation, release of tamponade and direct cardiac compressions +- bypass if required and is recommended if in suitable ICU. Outside of this has poor results
  • Echo is very useful to identify potentially reversible causes
  • Chest compressions should NOT be witheld while preparing for re-sternotomy

• PCI
  • Mechanical CPR during PCI
    • Case reports of successful therapy
  • Cough CPR
    • Case reports of successful maintenance of cerebral perfusion with forceful, repeated coughing in the setting of sudden arrhythmia in an EP lab with subsequent defibrillation/cardioversion
    • Can be considered in initial seconds while conscious in VF or pulseless VT in witnessed, monitored, hospital setting
• Pericardial tamponade
  • Clinical
    • Raised JVP
    • Dyspnoea
    • Orthopnoea
    • Muffled heart sounds
    • Tachycardia
    • Hypotension
    • Pulsus paradoxus >10mmHg (exaggerated drop in systolic BP with inspiration)
    • Electrical alternans on ECG
    • Microvoltage on ECG
    • Enlarged cardiac silhouette on CXR
  • Echo findings
    • Pericardial effusion: Mild (<10mm), Moderate (10-20mm), Large (>20mm) [measured in diastole]
    • Swinging heart
    • Systolic collapse of RA
      • Seen before diastolic collapse in atria as filling pressure is lower during systole
    • Diastolic collapse of RA
      • Atria affected before ventricles due to lower pressure
      • Seen in late diastole first
    • Diastolic collapse of RV
      • Seen in early diastole first
      • The greater the duration within diastole, the more clinically significant
    • IVC engorgement (>1.5cm, <50% inspiratory collapse)
  • Non-traumatic
    • Pericardiocentesis (preferably echo-guided) is recommended in peri-arrest/arrest situation
    • Placement of pericardial drain may obviate need for later operative management
    • Emergency thoracotomy can be considered if pericardiocentesis not possible
  • Traumatic
    • Definitive surgical drainage preferred then emergency thoracotomy and if neither of these possible, then pericardiocentesis should be attempted

• Pregnancy
  • Most commonly due to:
    • Cardiac disease
    • PE
    • Haemorrhage
    • Sepsis
    • Hypertensive disorders of pregnancy
    • Poisoning and self-harm
    • Amniotic fluid embolism
    • Anaphylaxis, trauma
  • Physiological changes
    • Hypoxia occurs more rapidly, intubation is more difficult, reflux is more likely
    • Gravid uterus compresses abdominal organs and iliac/abdominal vessels
    • Can lose up to 33% of blood volume before hypotension ensues
  • Effective maternal resuscitation is the key to foetal survival
  • Must release aortocaval compression, 
  • Summon obstetric and paediatric help and neonatal help immediately
  • Manually displace uterus and tilt left hip up 15-30 degrees
  • Consider preparation for emergency C-section

• PE
  • One double-blind RCT showed no improvement in survival to discharge from tPA use in PEA arrest
  • Continued CPR for 30 minutes following fibrinolysis was used in the largest trial to date
    • Should give at least 30 minutes
    • Consideration should be given to continuing CPR for 60-90 minutes
  • Fibrinolytic therapy may be considered if PE suspected in arrest
• Stacked shocks
  • Recommended if:
    • Witnessed, monitored arrest
    • Defibrillator immediately available with shock available within 20 seconds
    • Time required for rhythm recognition and charging <10 seconds
  • If no ROSC within 10 seconds of third shock, start CPR. 
  • If non-shockable and no ROSC within 10 seconds, start CPR

• Hypoxia
  • PEA within 3-11 min of complete apnoea/airway obstruction
  • Faster if obstructed vs. apnoea as vigorous respiratory efforts ensue
  • VF only 0.5% of initial rhythms
  • Treating cause is highest priority with effective ventilation
  • Follow standard ALS protocol
  • Survival is rare in this group despite 1/3 achieving ROSC

• Hypo/hyperkalaemia/metabolic
  • Typically ECG changes occur at >6.7mmol/L (ILCOR)
  • If strongly suspected, start treatment before lab confirmation
  • Avoid salbutamol monotherapy (may be ineffective)
  • Insufficient evidence to support sodium bicarbonate
  • Main risks of therapy are hypoglycaemia, tissue necrosis, intestinal necrosis and rebound hyperkalaemia once drug effect wears off (4-6 hours)
  • Treatment algorithm
    • Mild (5.5-5.9): Address cause + Resonium 30g (takes 4 hours)
    • Moderate (6.0-6.4): Insulin/dextrose + Resonium 30g
    • Severe (>6.5) without ECG changes: Insulin/dextrose, salbutamol 20mg, resonium +- dialysis
    • >6.5 with ECG changes: Calcium, insulin/dextrose + salbutamol + resonium/dialysis
  • Modifications to ALS
    • Confirm hyperkalaemia early
    • Protect heart with calcium chloride 10% 10mL bolus
    • Insulin/dextrose
    • 50mmol sodium bicarbonate push
    • Dialysis
• Hypokalaemia
  • If unstable – 2mmol/min for 10 min then 10mmol over 5-10 min
    • 0.05mmol/kg stat in children
  • Replace Mg with it

• Hypermagnesaemia
  • Mg >1.1
  • Consider treatment if >1.75
  • Calcium chloride 10% 5-10mL PRN
  • IV N/saline
  • Frusemide 1mg/kg
  • Dialysis
• Hypomagnesaemia
  • 5mmol IV stat then 10mmol/hr
• Hypothermia
  • Intact neurological recovery may occur with prolonged resuscitation efforts especially if deep hypothermia occurs before arrest
  • Look for signs of life for at least 1 minute and if any doubt start CPR
  • Do not delay careful intubation as required
  • Consider mechanical chest compression devices due to stiff chest wall
  • Confirm hypothermia with low-reading thermometer
  • Double dose interval of drugs from 30-35 degrees
  • As core temperature decreases  Sinus brady, AF,  VF, asystole in that order
  • Give up to 3 shocks at <30 degrees but then just focus on rewarming

• Hypovolaemia
  • Fluid replacement + immediate control of fluid loss
• Anaphylaxis
  • Immediate IM adrenaline 10mg/kg up to 0.5mg
  • Supine always
  • Remove trigger
  • Follow usual ALS guidelines
  • Early airway interventions if angioedema
  • IV fluids 20mL/kg PRN
  • Adrenaline 50mcg boluses IV (1mcg/kg in children)
  • Adrenaline infusion 0.05-0.5mcg/kg/min
  • 100% Oxygen as soon as possible

• Traumatic cardiac arrest
  • Very high mortality but if ROSC achieved, neurological outcome is much better than other causes
  • Treatment of reversible causes takes priority over chest compressions
  • Children have better prognosis than adults
  • VF is rare but carries the best prognosis
  • PEA and asystole predominate
  • Consider withholding resuscitation if:
    • No signs of life in previous 15 minutes
    • Decapitation, penetrating heart injury, loss of brain tissue
  • Consider terminating resuscitation efforts if:
    • No ROSC after reversible causes ruled out
    • No detectable cardiac activity on echo
  • Priority life threats
    • Control external haemorrhage
    • Control airway and maximise oxygenation
    • Bilateral chest decompression
    • Relieve cardiac tamponade
    • Surgery for haemorrhage control or proximal aortic compression
    • MTP
  • DCR
    • Hypotensive resuscitation  Haemostatic resuscitation  Damage control surgery
  • 50% due to uncontrolled haemorrhage, 13% airway, 13% tension PTX, 10% cardiac tampoande
  • Hypotensive resuscitation best proven in penetrating trauma in military setting but has been recommended for all now
  • Careful with head injury and should not continue beyond 60 minutes in any circumstance

• ILCOR resuscitative thoracotomy
  • After arrival in hospital, decision to proceed if:
    • Blunt trauma with <10min of prehospital CPR
    • Penetrating trauma with <15min of CPR
  • Overall survival 15% for penetrating wounds and 35% for penetrating cardiac wounds
  • 0-2% survival for blunt trauma
  • The Four E’s
    • Expertise
    • Equipment
    • Environment
    • Elapsed time: < 10 min from loss of vital signs ideally
  • If any of the 4E’s are not present = Futile and exposes team to unnecessary risks

• Tension PTX – Needle decompression or preferably finger thoracostomy then formal drain
• Cardiac tamponade – Thoracotomy for traumatic or USS- guided pericardiocentesis takes priority
• PE
  • 2-9% of all OOHCA
  • 5-6% of all IHCA
  • If 12-lead available prior to arrest, may show RV strain:
    • V1-4 TWI
    • QR pattern in V1
    • S1Q3T3
    • Incomplete or complete RBBB
  • Fibrinolytics increase rate of ROSC, survival to discharge and long-term neurological outcome in arrest due to PE
  • Alteplase 50mg IV stat then 50mg over an hour or second bolus if ROSC not achieved
  • Consider surgical embolectomy/ECMO

• Toxins
  • Low threshold to ensure personal safety in possible exposure arrest
  • Avoid mouth-t0-mouth if possible cyanide, hydrogen sulfide, corrosives or organophosphates
  • Try to identify the poison
  • Prolonged resuscitative efforts
  • HIET, intralipid, prolonged CPR, ECMO and haemodialysis should be considered early
  • Consider decontamination, enhanced elimination and reversal agents early

• Drowning
  • Bradycardia due to asphyxia prior to arrest
  • Drowning chain of survival
    • Prevent drowning
    • Recognise distress
    • Provide flotation
    • Remove from water
    • Provide care as needed
  • Remove victim from water ASAP
    Spinal precautions only required if history of dive into shallow water, signs of severe injury after water-slide use, waterskiing, kite surfing or wavecraft racing
  • Do not confuse agonal with normal breathing
  • Opening airway and providing 5 rescue breaths is priority number 1
  • Consider early intubation if fails to respond

• Lightning
  • Lichtenberg figures are pathognomonic
  • Give priority to victim with no signs of life if multiple
  • Better outcomes than other causes of arrest
  • VF most common arrhythmia after AC vs. asystole most common after DC shock
• Pregnancy
  • Manual displacement of uterus + left lateral tilt should be considered although no evidence of resuscitative benefit
  • Resuscitative hysterotomy should occur within 4 minutes of maternal death
    • <20 weeks need not be considered
    • 20-23 weeks: May save mothers life
    • 24 weeks +: May save mother and foetus

Sepsis

• Cardiac arrest in sepsis has worst outcomes of all
• Survival is close to 0% if arrest occurs despite adequate volume resuscitations, antibiotics and pressors

Ventricular assist device

• Continuous blood flow so do not have pulse
• Patient may remain conscious despite VF
  • Defibrillation is performed in controlled environment
• Chest compressions cause retrograde flow and may damage aortic graft
• Flow is present if:
  • VAD controller screen shows a flow volume or pump activity is audible on auscultation
• If flow <1.5L/min
  • Check all device connections, start CPR/ALS (including defib if indicated), check for flow with USS and connect VAD to AC power, consider ECMO
• If flow 1.5-2.5L/min or MAP <40
  • Do not start CPR, give 250mL N/S bolus and commence adrenaline infusion
• If flow >2.5L/min
  • Consider alternative causes for ALOC

Toxicology

• Benzodiazepines
  • Flumazenil use is not recommended
  • No other clear recommendations
• Beta-blockers
  • Follow standard resuscitation guidelines
  • Case reports and animal studies of glucagon, HIET
• Calcium channel blockers
  • Follow standard resuscitation guidelines
  • Calcium supplementation recommended elsewhere
  • Case series of HIET
• Carbon monoxide
  • If cardiac arrest, rarely survive to hospital discharge
  • Hyperbaric oxygen can be considered as many improve neurological outcome
  • Cardiology follow-up recommended for patients who suffer myocardial injury in setting of CO poisoning as have increased risk of cardiac and all-cause mortality for at least 7 years
• Cocaine/amphetamines
  • IV benzos are first-line
  • GTN and phentolamine effective for coronary vasoconstriction
  • Follow standard resuscitation guidelines
• Cyanide
  • Hydroxocobalamin showed no adverse effects and improved survival
  • Sodium thiosulphate showed no adverse effects
  • Sodium nitrite, amyl nitrite also showed similar effects with some adverse effects
  • Severe cardiac toxicity (cardiac arrest, instability, metabolic acidosis or altered mental status) should receive cyanide antidote therapy
    • Immediate parenteral hydroxocobalamin 5mg with repeat dosing up to 15mg
• Digoxin
  • If cardiac arrest occurs, follow standard resuscitation guidelines
  • If severe cardiac toxicity, anti-digoxin Fab fragment therapy should be administered
• Local anaesthetic
  • Refractory seizures, dsyrhythmia and cardiovascular collapse
  • Five case reports of ROSC after intralipid 
  • Recommendation to follow usual guidelines and that intralipid may be effective in refractory cases
• Opioids
  • In cardiac arrest: Naloxone offers no survival benefit beyond usual resuscitation
  • In pre-arrest setting: Ventilation first, then naloxone, then intubation if no response
    • If respiratory arrest: 100mcg aliquots to achieve spontaneous respiration and airway control vs. 2mg for total reversal risking acute withdrawal response

• TCA
  • Priority is control of pH to 7.5 with hyperventilation
  • Consider sodium bicarbonate during arrest and post-cardiac arrest if TCA and wide QRS
  • When mechanical ventilation is required, respiratory acidosis must be avoided

ECPR

• ECMO use is a recent introduction
• Bridging therapy to PCI, CABG or heart transplant
• Indications
  • Good premorbid status
  • Intervention to be curative, not palliative
  • Reversible trigger for event e.g. dysrhythmia, STEMI
• Contraindications
  • Advanced age, advanced malignancy, poor baseline function, ARP in place
  • Suspect aortic dissection or severe AR, traumatic cardiac arrest
  • Unwitnessed cardiac arrest and no bystander CPR, long prehospital transport time, prolonged cardiac arrest unless good perfusion and metabolic support documented
• ARREST trial 2020
  • ECMO facilitated resuscitation increased survival to hospital discharge in USA
  • 1/15 survived in conventional ALS vs. 9/15 in ECMO group
  • Small open label randomised study
  • Only OOHCA with refractory VF (no ROSC after 3 shocks)
  • Involved deployment of ECMO team within 20 minutes of 911 call
  • ECMO group went straight to cath lab bypassing ED
  • Standard care went to ED
  • Both groups had an ABG on arrival with cessation of efforts if 2 or more of:
    • etCO2 <10
    • PaO2 <50 or SpO2 <85%
    • Lactate >18
  • If ROSC went to angio/angioplasty
  • Mean age 59, 80% men
  • In ECMO group, mRS improved over the follow-up 6 months from around 4 in survivors to 2 du to improvements in mobilisation/strength
  • Only survivor in standard care group died at <3 months

Cardiac arrest in trauma

• First priority is to stop bleeding
• Restoration of circulating volume may have higher priority than A and B
• All patients in cardiac arrest with suspected chest trauma not responding to airway opening and fluids should have chest decompressed
• Surgical drainage of traumatic cardiac tamponade is preferred to percutaneous intervention
  • Percutaneous drainage can be attempted if arrest/peri-arrest with no surgical option immediately available
• Penetrating trauma is more likely to benefit from emergency thoracotomy than blunt trauma
• If >10min from time of arrest, emergency thoracotomy is unlikely to be of benefit
• Cardiac arrest due to isolated head injury, crush syndrome and commotio cordis are specific circumstances requiring specific therapy
• Haemorrhage control, restoration of volume, opening airway and chest decompression take precedence over CPR (should continue simultaneously if able)
• >10 min CPR in traumatic cardiac arrest after reversible causes have been addressed has dismal prognosis

• 3 preventable causes of early death
  • Airway obstruction (7%)
  • Tension PTX (33%)
  • Haemorrhage (60%)
• 5-7.5% survival to hospital discharge
• Ideally 2x18G cannulas
• IO often more achievable than IV or CVL
  • In adults, humeral head or sternum allows more rapid infusion
  • Can put 2 in

• Fluids
  • Warmed fluids 20mL/kg stat
  • In exsanguinating haemorrhage, 1:1 or 1:2 FFP:PRBC
  • Use of cryoprecipitate, fibrinogen and platelets should be based on MTP
  • Maintain iCa >1.1
  • Once ROSC achieved, prior to surgical haemorrhage control and at least for the first hour, should titrate fluids to SBP >90 or consciousness (>110 if head injury suspected)
  • Progressive improvement in lactate and base excess are reasonable targets after this first hour

• Sodium bicarb should only be used to correct acidosis if treating hyperkalaemia OR crush injury
• Chest decompression
  • Finger preferred
  • 3-4cm incision over 4^th ICS anterior to mid-axillary line then blunt dissection and insert finger
  • Place ICC if available after this
  • If more than 1L of blood drains immediately or ongoing bleeding >200mL/hr for next 2-4 hours, surgical exploration is warranted
  • Should be accompanied by intubation and ventilation due to risk of air entering pleural space and preventing adequate ventilation
  • Needle decompression is another option that may be faster followed by finger thoracostomy

• Resuscitative thoracotomy
  • Penetrating thoracic injury with
    • Previously witnessed cardiac activity
    • Unresponsive hypotension <70mmHg
  • Blunt thoracic injury with
    • Rapid exsanguination from chest tube (>1.5L immediately)
    • Unresponsive hypotension <70mmHg
  • Relative
    • Penetrating thoracic injury with traumatic arrest without previously witnessed cardiac activity
    • Penetrating non-thoraracic injury with traumatic arrest and previously witnessed cardiac activity
    • Blunt thoracic injuries with traumatic arrest with previously witnessed cardiac arrest
  • Contraindications
    • Blunt injury without witnessed cardiac activity
    • Penetrating abdominal injury without witnessed cardiac activity
    • Non-traumatic cardiac arrest
    • Severe head injury/multitrauma
    • Improperly trained team
    • Insufficient equipment

• Crush syndrome
  • Consider hyperkalaemia as contributory
  • Treat with calcium, glucose, insulin and sodium bicarbonate 1mmol/kg
• Commotio cordis
  • Early defibrillation carries same high priority as per normal guidelines
• Isolated major head injury
  • May cause isolated apnoea that will respond to airway and breathing as first priorities as usual

• Adrenaline
  • Not recommended until haemorrhage control, opening airway, commencement of restoration of circulating volume and decompression of chest if appropriate
  • More applicable to later phases of resuscitative care once volume restored and vasodilation/myocardial depression ensue
• Defibrillation
  • Only 7.5% of patients in traumatic cardiac arrest have initial shockable rhythm
  • Not recommended prior to opening airway, commencement of restoration of circulating volume and decompression
• Transport
  • Recommended to transport to hospital only after ROSC unless could realistically obtain resuscitative thoracotomy within 10 minutes (and deemed necessary)

• Termination of resuscitation
  • Recommended to continue resuscitative measures for up to 10 minutes after potentially reversible causes have been addressed
• If first on scene, priority is transportation vs. BLS/ALS as need equipment to save the person

Cessation of CPR

• ROSC achieved – Only once perfusion confirmed by pt moving, etCO2 rising and stable cardiac rhythm of suitable rate
• No ROSC
  • 20 minutes of CPR without reversible cause AND
    • Non-shockable rhythm AND
    • No ROSC before ED transportation AND
    • Non-witnessed arrest
  • Trauma and absent cardiac activity on echo
    • 99% mortality if cardiac activity absent
    • 70% mortality if cardiac activity present
  • Absent cardiac activity on US and etCO2 <10 after second cycle ALS
    • Close to 0% survival
  • PEA/Asystole in presence of:
    • OHCA unwitnessed by EMS
    • No ROSC before 3^rd dose adrenaline
    • Survival to hospital discharge 0 – 0.5%
• Exceptions
  • Toxicology, asthma, hypothermia, pregnancy if post-mortem C/S considered

etCO2

• Phase I – No CO2 as from dead space
• Phase II – Initial upslope from mixed dead space/gas-exchanging airways
• Phase III – Alveolar plateau
• End-tidal point – Peak at end of expiration
  • Normally 35-40mmHg

• Changes to trace
  • Upsloping alveolar plateau in obstructive lung disease
  • Flattening of alveolar plateau in PE
  • Expiration phase shortens with deepening sedation
• Accuracy +- 1%
• Usually 5mmHg less than PaCO2
• Serial etCO2 monitoring to monitor PaCO2 is acceptable if:
  • Good trace
  • Correlated with ABG
  • No rapidly changing pulmonary pathology
• EtCO2 may transiently exceed PaCO2 if ROSc or administration of bicarb

• Increased etCO2
  • Fever, sepsis, seizure, hyperthyroidism, bicarb, malignant hyperthermia, increased cardiac output (e.g. ROSC) or reduced alveolar ventilation
• Decreased etCO2
  • Decreased temperature, increased sedation, paralysis, reduced pulmonary blood flow (reduced cardiac output, PE, air embolism, hypovolaemia), increased alveolar ventilation or equipment malfunction (disconnect, ET dislodged, airway obstruction by secretions, large leak around ET

Neuromuscular blockade

• Train of four interpretation
  • As level of block increases, T4 disappears, then T3, T2 then T1
  • Single contraction = 90% blockade
  • Fade
    • T4 disappears at 75% depression of T1
    • T3 disappears at 80-85% depression of T1
    • T2 disappears at 90% depression of T1
  • If no response = pharmacologically irreversible
  • Reversal can be achieved with drugs if TOF count is 3 or higher
  • Extubation can be performed if TOF ratio > 90% 

MET calls

• Rapid response teams are programs designed to identify deteriorating patients to prevent further deterioration
• Criteria for activation
  • Usually objective vital signs + at least one subjective ‘staff member worried
• 24 hours a day and response within 15 minutes
• No negative consequences for activation
• Team members must:
  • Ability to diagnose problem
  • Ability to initiate therapy
  • Authority to transfer to higher level of care
• Needs feedback loop

• Efficacy
  • Two unblinded randomized trials and the rest lower quality observational studies
  • MERIT
    • 125000 patients in Australia
    • No detectable difference in unexpected mortality, cardiac arrests or unplanned ICU admissions
  • Prietley et al. (2004)
    • 2903 UK patients matched for acuity
    • Reduced in-hospital mortality
  • Systematic reviews and meta-analyses of observational studies have shown reduced in-hospital mortality and reduction in arrests in non-ICU patients

• Potential disadvantages
  • Reliance may reduce sense of responsibility of ward staff
  • Confusion as to who carries primary responsibility
  • Expense
  • Excessive review of patients with abnormal vitals who are NOT at risk of arrest

Refractory VF/VT

• Defined as ongoing VF/VT after 3 shocks separated by 2 minute intervals of CPR
• Amiodarone 300mg + repeat 150mg if required
• Maximal energy defib (360J)
• Consider early initiation of Lucas/Mechanical CPR to prevent fatigue
• Consider double sequential defibrillation (Sternum/Apex and AP) -> Both at 360J and one immediately after the other (simultaneously charged)
  • Survival to hospital discharge 30% vs. 13% (Cheskes et al.)
• Consider esmolol/Minimise adrenaline
  • Driver et al. (2011) Resuscitation
  • 500mcg/kg loading dose and 50mcg/kg/min infusion of esmolol
  • 6 patients received esmolol vs. 19 did not
  • Sustained ROSC achieved in 4 (67%) of esmolol group and 6 (31%) of no esmolol
  • Survival to hospital discharge in 3 (50%) of esmolol and 3 (33%) of no esmolol group
• ECMO
• Cath lab for vast majority

Vasopressin and Methylprednisolone

Mentzepoulos et al. (2009)

• Single-centre, prospective, randomised, double-blind, placebo-control trial
• 100 consecutive patients with in-hospital cardiac arrest
• Received 40mg methylpred plus 20IU vasopressin + adrenaline or placebo + adrenaline for first 5 resuscitation cycles
• ROSC in 81% of drug arm vs. 52% of placebo
• Survival to hospital discharge in 19% of drug arm vs. 4% of placebo arm

Mentzepoulos et al. (2013)

• 268 eligible patients across 3 Greek hospitals
• Same regime as above
• Shock after resuscitation was additionally treated with hydrocortisone 300mg daily for 7 days vs. placebo
• Higher rate of ROSC at 20 minutes (83.9% vs. 65.9%) and survival to hospital discharge with good neurological outcome (13.9% vs. 5.1%)

Andersen et al. 2021

• 501 in-hospital cardiac arrest patients randomised in Denmark to:
  • 40mg methylpred + 20IU vasopressin as soon as possible after first adrenaline dose
    • Additional 20IU vasopressin doses with each adrenaline dose thereafter up to a maximum of 4 doses
  • Vs. placebo
• In-hospital arrests only
• ROSC in 42% of drug arm vs. 33% of placebo arm
• Statistically significant
• No difference in survival or survival with good neurological outcome at 30 days but not designed for this

Last Updated on November 10, 2023 by Andrew Crofton