Cardiac arrest and its management

CARDIAC ARREST MANAGEMENT

Cardiac arrest is defined as abrupt loss of cardiac pump function which may be reversible by a prompt intervention or may lead to death in its absence.

Basic life support –
Airway : clear foreign objects ; remove dentures; lift tongue away if causes obstruction. Chin lift, head tilt method – contraindicated in cervical spine injury.

Breathing : if not breathing; moth to mouth resuscitation given at rate of 10 – 12/min
In case of foreign body obstructing larynx, Heimlich’s manouver done.

Circulation : Cardiac compression done in supine position on firm surface
Cardiac compression of 15 : 2 breaths at rate of 80 – 100/min

Precordial thump : help to terminate Ventricular fibrillation.(AE : may progress V tachycardia – v fibrillation – asystole.)

Automated External defibrillator : capable of analyzing cardiac rhythm and if appropriate deliver electric countershock.

Advanced Cardiac Support

Use of drugs and defibrillator to control the the activity of heart and achieve good cardiac output. Basic rythms in cardiac arrest : asystole, electromechanical dissociation and ventricular fibrillation.

3 successive shocks : 200, 300, 360 Joules delivered (confirm absence of pulse before each shock)

If initial defib not successful CPR restarted and drugs administrated.

Drug of choice, IV Adrenaline in 1 mg (1:1000) solution repeated every 2-5 mins.
Each dose of Adrenaline is followed by !) CPR sequences & 3 successive shocks at 360 J. If does not recover after 4 doses Adr & 12 shocks, administer Amiodarone or Lignocaine.

Amiodarone, 300mg bolus; Iif required, 150 mg repeated after 3-5 min.Followed by Amiodarone infusion.

Aystole : If Ventricular fibrillation cannot be excluded ; treat with 3 shocks as for VF Adrenaline 1 mg followed by 10 CPR sequences & 3 mg Atropine.

EMD : Indicates pump failure despite normal or near normal activity of heart.End stage event in advanced heart disease.; or as manifestation of acute ischemic insult.

Management of cardiac arrest

1.confirm diagnosis
-check pulse, start CPR

2.Airway- head tilt chin lift. Clear airway, do suction, remove dentures

3. Assess presence of respiration .IF no give 2 breaths mouth to mouth

4.Circulation.-Palpation for carotid pulse.If no pulse deliver 30 compressions then 1 breath.

5.When help arrives, give 100% oxygen via ambu bag, set iv line start 1000ml normal saline and ECG leads placed. Carry on CPR except during intubation and defibrillation. Not more than 30s allocated for intubation. Once intubated,ventilations given at the rate of 12-15 per minute without pausing for compressions.

6.Subsequent management depend on ECG rhytm.

7.Prepare following drugs –adrenaline, lignocaine , bicarbonate ,isoprenaline

8.If cardiac arrest persist for more than 30 mins, resuscitation is unlikely to be successful .Check for signs of brain death.


*ventricular fibrillation and pulseless ventricular tachycardia

-defibrillate 200j. check pulse. Recharge , give 30 chest compressions.
-adrenaline 1mg iv
-defibrillate 360j within 30-60s check pulse again
-medication- aimodarone 150mg iv lignocaine 1-1.5mg/kg

Management of cardiac arrest.

Initial management of cardiac arrest

-Confirm the diagnosis ( unconscious, absent carotid impulse or femoral pulse), check the time, start CPR and call for help.


Check responsiveness
( Shake and shout )





Open airway
( Head tilt / chin lift )
Clear the airway


Breathing
( Look, listen and feel)
Asses the presence of respiration.
If no spontaneous, give 2 breaths mouth to mouth.
If breathing, put in recovery position.




Asses, signs of circulation
( 10 seconds only), Palpate the carotid pulse, if pulse not present, deliver 15 chest compression at a arate of 80-100/min. After 15 compressions, deliver 2 rescue breaths( ratio 15: 2) for rescuers, the compression- ventilation ratio is is 5:1

If circulation present continue rescue breathing and check circulation every 15 minutes.



When help arrives, give 100 % oxygen via Ambu- bag, set up iv line at the antecubital fossa( not at the hand or wrist)- 1000 ml of normal saline is infused and ECG leads are placed. Carry on CPR except during intubation and defibrillation. Not more than 30 seconds should be allowed for intubation. If intubation failed, restart compression. Once the patient is intubated, ventilation can be given at a rate of 12-15 mins, without pausing for compression.





Prepare the following drugs
- 10 ml 1:10 000 or 1ml 1:1000 adrenaline.
- Lignocaine 100 mg iv
- Bicarbonate 50 ml 8.4%
- Isoprenaline 2mg in 500ml 5 % dextrose

If IV access fails, adrenaline , atropine and lignocaine can be given via ETT but double the normal IV dose.

If cardiac arrest has been persisted for more than 30 minutes, resuscitation is unlikely to be successful. Check for signs of brain death.

Patient should be monitored carefully. Antiarrhythmic agents are necessary in Ventricular fibrillation. Fluid balance, ABG, CVP, urine output and electrolytes need to be monitored closely and treated appropriately.




Specific Arrest sequence.

Ventricular fibrillation and pulseless ventricular tachycardia

Precordial thump in witnessed arrest

Defibrillate 200 J. Check pulse, recharge, give 15 shect compressions, check monitor.

Defibrillate 200- 300 j. Check pulse, recharge, give 15 chest compressions, check monitor.

Defibrillate 360 , Check pulse, recharge, give 15 chest compressions, check monitor.

Intubation if not already.

Adrenaline 1mg IV or ETT or vasopressin 40 u IV, single dose, 1 time only.

Defibrrilate 360 j within 30-60 seconds. Check pulse, recharge, give 15 chest compression and check monitor.

Administer medications of probable benefit in persistent or recurrent VF/ VT




Medications.
Amiodorone 150mg Iv( in 100 ml D5 %) over 10 minutes can be
repeated.

Lignocaine 1.0-1.5 mg/kg Iv push. Repeat 3-5 minutes to maximum dose of 3mg/kg
.
Magnesium sulphate 1-2g Iv in torsade de pointes, suspected hypomagnesaemic state or refractory VF

Procainamide 30 mg/min to maximum total dose of 17 mg /kg in refractory VF.



Asystole

-CPR ( if rhythm is unclear and possible VF, defibrillate as for VF.
-Adrenaline 1mg IV or ETT.
-Intubation if not already.
-Consider possible causes and initiate appropriate treatment of identified hypovolaemia, hyper or hypokalemia., hypoxaemia, hypothermia, acidosis, cardiac temponade.
-Consider immediate transcutaneous pacing
-Adrenaline 1mg iv push repeated every 3- 5minutes
-Atropine 1mg iv push or 2 mg ETT, repeat every 3-5 minutes up to total dose 0.04 mg/kg


If no response, consider,
-High dose adrenaline regime e.g 2-5 mg iv push every 3-5 mins or 1mg-3mg – 5 mg iv push ( 3mins apart)
-Consider bicarbonate 50ml of 8.4 % IV.
-Termination of efforts.


Electromechanical dissociation( EMD)

-CPR
-Adrnenaline 1mg push iv push, repeat every 3-5 mins.
-Atropine 1mg Iv push or 2 mg by ETT , repeat every 3-5 minutes up to total dose of o.o4 mg/kg.
-Rule out hypovolaemia , hyper or hypokalaemia .
-Consider
- calcium, bicarbonate and adrenaline 5mg iv.

Management of Cardiac Arrest

In a possible cardiac arrest:

• Assess responsiveness
• A precordial thump may be performed in a witnessed arrest where no defibrillator is available
• Confirm airway, breathing, and circulation (ABC):if needed, perform cardiopulmonary resuscitation (CPR)
• As CPR continues, assess rhythm

The ACLS Comprehensive ECC Algorithm divides into two treatment pathways depending on whether the monitored rhythm is VF/VT or non-VF/VT

If the monitored rhythm is VF/VT with no pulse:

• Defibrillate immediately at 200J
• If VT/VT persists, defibrillate at 200-300J
• If VT/VF persists, defibrillate at 360J
• There is no need to lift the paddles off the chest in between these 3 shocks unless there is a response
• If there is no response (check for pulse), continue CPR for 1min
• During this time, perform a secondary survey
• The secondary survey includes ensuring an adequate, secure airway; gaining intravenous access; and administering an adrenergic medication which should not replace or delay continued defibrillations per protocol
• The recommended adrenergic agent is vasopressin 40units given intravenously once only; or epinephrine 1mg intravenously repeated every 3-5min. If there is no response to vasopressin, epinephrine can be resumed but not for 10-20min
• After 1min of CPR, assess rhythm
• If VF/VT persists and there is still no pulse, repeat the cycle of one 360J shock followed by 1min of CPR and secondary ABCD survey
• Continue this cycle until either there is a response; the monitored rhythm changes to a non-VF/VT rhythm; or a decision is made to discontinue resuscitation

Where VF/pulseless VT persists:

• Continue to administer epinephrine every 3-5min in a drug-shock-drug-shock sequence
• During the secondary survey phase, search for a reversible cause of the arrest
• Also consider other antiarrhythmics and buffer agents
• Be cautious as using more than one antiarrhythmic medication may result in an arrhymia due to a drug interaction
• Amiodarone 300mg intravenously and repeated once at 150mg in 3-5min is the antiarrhythmic of choice
• Magnesium sulfate 1-2g intravenously (>2min) may be considered for suspected hypomagnesemia or torsades de pointes
• Procainamide 20mg/min or 100mg intravenously over 5min for refractory VF
• Lidocaine is another possible antiarrhythmic. Consider sodium bicarbonate 1mEq/kg intravenously if cardiac arrest or CPR have continued beyond 10min
• If the monitored rhythm is non-VF/VT:
• Confirm asystole by checking in another lead with properly functioning equipment
• If transcutaneous pacing is to be effective in cases of asystole, it has to be performed immediately
• Continue CPR for up to 3min
• During this time, perform secondary survey
• Included in the secondary survey is the need to ensure an adequate, secure airway; to gain intravenous access; and to administer epinephrine 1mg intravenously, repeated every 3-5min
• In cases of asystole, administer atropine 1mg intravenously every 3-5min (up to 2mg)
• Assess rhythm every 3min as CPR continues
• The treatment pathway for pulseless electrical activity (PEA) is the same as for asystole although atropine is given only if electrical activity is slow
• During the secondary survey it is important to search for a possible cause for PEA and intervene accordingly

Causes of PEA include: pulmonary embolism; acidosis; tension pneumothorax; cardiac tamponade; hyperkalemia; hypothermia; hypovolemia; hypoxia; massive myocardial infarction; and drug overdose
Resuscitative efforts should be terminated if reversible causes of cardiac arrest have been treated and arrest is refractory to all of the above treatments.

Following return of spontaneous circulation:

• Patients with VF/VT should have continuous intravenous infusion of the successful antiarrhythmic therapy until they are stabilized
• Ventricular fibrillation without an identifiable cause requires electrophysiologic testing and possible chronic therapy with either prophylactic antiarrhythmic agents (amiodarone, sotalol) or implantation of a cardioverter-defibrillator
• Implantable cardioverter-defibrillators (ICDs) are indicated for patients surviving cardiac arrest due to VF or VT not due to a transient or reversible cause

MANAGEMENT OF CARDIAC ARREST

Initial management :
1)confirm the diagnosis-unconscious, absent carotid or femoral pulse
Check the time, start CPR and call for help
2) AIRWAY : Extend the neck by head tilt and chin lift. Clear the airway
3)BREATHING : Assess for the presence for respiration. If no spontaneous response,give 2 breaths mouth-to-mouth.
4) CIRCULATION : Palpate for carotid pulse. If l pulse is not present, deliver 15 chest compressions at a rate of 80-100/min. After 15 compressions,deliver 2 rescue breaths (ratio 15: 2). For 2 rescuers the compression-ventilation ratio is 5:1.
5) When help arrives give 100 % oxygen via ambu-bag, set up IV line at the antecubital fossa (not at the hand or wrist) – 1000 ml of normal saline should be infused and ECG leads placed.Carry on CPR except during intubation and defibrillation. Not more than 30 seconds should be allocated for intubation..If intubation fails, restart compressions. Once the patient is intubated, ventilations can be given at a rate of 12-15/min, without pausing for compressions.
6) Subsequent management will depend on ECG rhythm.
7) prepare the following drugs : 10 ml 1:10 000 or 1 ml 1 : 1000 adrenaline.
Lignocaine 100 mg IV
50 ml bicarbonate 8.4%
Isoprenaline 2mg in 500 ml 5 %
dextrose
If IV access fails, adrenaline,atropine, and lignocaine can be given via an ETT but double the normal IV dose.
If cardiac arrest has persisted for more than 30 minutes, resuscitation is unlikely to be successful. Check for signs of brain death.
After successful resuscitation, it is important that the patient be monitored carefully. Antiarrhythmic agents are necessary in VF or VT. Fluid balance, ABG, CVP, urine output and electrolytes need to be monitored closely and treated appropriately. Dopamniergic support may be needed.

Specific management :

1) VENTRICULAR FIBRILLATION AND PULSELESS VENTRICULAR TACHYCARDIA

· Precordial thump in witnessed arrest.
· Defibrillate 200J. Check pulse,recharge, give 15 chest compressions,check monitor.
· Defribillate 200-300J.Repeat as above
· Defribillate 360J.repeat as above.
· Intubation of not already.
· Adrenaline 1mg IV or ETT or Vasopressin 40 U IV, single dose,1 time only.
· Defibrillate 360J within 30-60 secs.Check pulse,recharge give 15 chest compressions,check monitor.
· Administer medications of probable nebefit in persistent or recurrent VF/VT
· Medication sequence :
- Amiodarone 150 mg IV )in 100 ml D5%) over 10 min, can be repeated
- Lignocaine 1-1.5mg/kg IV push. Repeat 3-5 min to max dose of 3 mg/kg.
- Magnesium sulphate, 1-2 g IV in torsade de ponites suspected hypomagnesaemic state, or refractory VF.
- Procainamide 30 mg/min to max total dose of 17 mg/kg in refractory VF
There should be cycles of at least a further DC shock and continued CPR fpr 1 minute(approximately 10 sequences of 5 : 1 compression-ventilation) before each new drug is given
Defibrillate 360J. Change paddle position.Check pulse,recharge, give 15 chest comrpessions,check monitor.

· Adrenaline should be repeated every 3-5min
· Intubation is essential,however deribillation and adrenaline are more important initially if the patient can be ventilated without intubation.
· Value of sodium bicarbonate is questionable during cardiac arrest.
· If VF recurs after transiently coverting, use whatever energy level has previously been successful for defibrillation.
· Once VF has resolved, begin IV infusion of antiarrhymic agent that has aided resolution of VF

In an unresponsive patient---> open airway and look for signs of life. Call for resuscitation team.

Start CPR 30:2 until a defebrillator or cardiac monitor is attached---> Assess rhytmn of pulse.

Based on the rhythm, the patient can be shockable (VF/pulseless VT) or non-shockable (Asystole).

In a shockable patient,
a) Give 1 shock:
-150-360 J biphasic, or
-360 J monophasic

b) Immediately resume CPR 30:2 for 2 minutes and then assess the pulse rhythm again.


In a non-shockable patient,
a) Immediately resume CPR 30:2 for 2 minutes and then assess the pulse
rhythm.

During CPR:

• Correct reversible causes (hypoxia, hypovolemia, hypo/hyperkalemia, hypothermia, tension pneumothorax, cardiac tamponade, thrombosis-cardiac or pulmonary).

• Attempt/verify IV access, airway and oxygen supply.

• Give uninteruppted compressions when airway is secure (DO NOT interrupt CPR for >10sec, except to defibrilate).

• Give adrenaline every 3-5mins.

• Consider amiodarone, atropine, magnesium.

Resistant VF/VT consider:

• Amiodarone 300mg IV (peripherally if no central access). A further 150mg may be given followed by infusion of 1mg/min for 6 hours, then 0.5mg/min for 6 hours.
• Alternatives to amiodarone are:
  - Lidocaine 100mg IV; can repeat once; then give 2-4mg/min IV.
  - Procainamide 30mg/min IV to a total dose of 17mg/kg.

Asystole

• Give adrenaline 1mg immediately IV access is acheived. Give atropine 3mg IV onceif asystole + rate <60/min.

Treat Acidosis

• with good ventilation. Sodium bicarbonate may worsen intracellular acidosis and precipitate arrythmias, so use only in severe acidosis after prolonged resuscitation.

HOW TO MANAGE A CARDIAC ARREST

As medical personnel, cardiac arrest would be one of the most commonest conditions that we will be faced with. There are a few steps that HAVE to be taken in order to ensure a safe and successful outcome.There are the standard methods in the initial stages of management(emergency conditions), followed by more specific ones later depending on facilities and expertise available.

INITIAL MANAGEMENT;

confirm the diagnosis-unconscious, absent carotid or femoral pulse Check the time, start CPR and call for help
AIRWAY : Extend the neck by head tilt and chin lift. Clear the airway
BREATHING : Assess for the presence for respiration.
CIRCULATION : Palpate for carotid pulse. If l pulse is not present, deliver 15 chest compressions at a rate of 80-100/min. After 15 compressions,deliver 2 rescue breaths (ratio 15: 2). For 2 rescuers the compression-ventilation ratio is 5:1.

• When help arrives give 100 % oxygen via ambu-bag, set up IV line at the antecubital fossa (not at the hand or wrist) – 1000 ml of normal saline should be infused and ECG leads placed.Carry on CPR except during intubation and defibrillation. Not more than 30 seconds should be allocated for intubation..If intubation fails, restart compressions. Once the patient is intubated, ventilations can be given at a rate of 12-15/min, without pausing for compressions.

• Subsequent management will depend on ECG rhythm.

• prepare the following drugs : 10 ml 1:10 000 or 1 ml 1 : 1000 adrenaline . Lignocaine 100 mg IV 50 ml bicarbonate 8.4% Isoprenaline 2mg in 500 ml 5 % dextrose

If IV access fails, adrenaline,atropine, and lignocaine can be given via an ETT but double the normal IV dose.
If cardiac arrest has persisted for more than 30 minutes, resuscitation is unlikely to be successful. Check for signs of brain death.

Should resuscitation prove to be successful...
...it is important that the patient be monitored carefully. Antiarrhythmic agents are necessary in VF or VT. Fluid balance, ABG, CVP, urine output and electrolytes need to be monitored closely and treated appropriately. Dopamniergic support may be needed.



SPECIFIC MANAGEMENT

1) VENTRICULAR FIBRILLATION AND PULSELESS VENTRICULAR TACHYCARDIA

· Precordial thump in witnessed arrest.
· Defibrillate 200J. Check pulse,recharge, give 15 chest compressions,check monitor.
· Defribillate 200-300J.Repeat as above
· Defribillate 360J.repeat as above.
· Intubation if it has not been done already.
· Adrenaline 1mg IV or ETT or Vasopressin 40 U IV, single dose,1 time only.
· Defibrillate 360J within 30-60 secs.Check pulse,recharge give 15 chest compressions,check monitor.
· Administer medications of probable benefit in persistent or recurrent VF/VT

· Medication sequence :
- Amiodarone 150 mg IV )in 100 ml D5%) over 10 min, can be repeated
- Lignocaine 1-1.5mg/kg IV push. Repeat 3-5 min to max dose of 3 mg/kg.
- Magnesium sulphate, 1-2 g IV in refractory VF.
- Procainamide 30 mg/min to max total dose of 17 mg/kg in refractory VF
There should be cycles of at least a further DC shock and continued CPR fpr 1 minute(approximately 10 sequences of 5 : 1 compression-ventilation) before each new drug is given
Defibrillate 360J. Change paddle position.Check pulse,recharge, give 15 chest comrpessions,check monitor.
· Adrenaline should be repeated every 3-5min
· Intubation is essential,however deribillation and adrenaline are more important initially if the patient can be ventilated without intubation.
· Value of sodium bicarbonate is questionable during cardiac arrest.
· If VF recurs after transiently coverting, use whatever energy level has previously been successful for defibrillation.
· Once VF has resolved, begin IV infusion of antiarrhymic agent that has aided resolution of VF

3 MACHANISM OF CARDIAC ARREST:

i) VENTRICULAR FIBRILLATION

ii) ASYSTOLE

iii) ELECTROMECHANICAL DISSOCIATION


A. INITIAL MANAGEMENT:

. Confirm the diagnosis ( unconscious, absent carotid or femoral pulse) check the time, start cpr and call for help

. Airway: Extend the neck by head tilt and chin lift. clear the airway.

. Breathing: Assess for the presence of respiration. if n spontineous breathing, give 2 breath mouth to mouth.

. circulation: Palpate the carotid pulse. if pulse is not present, deliver 15 chest compression at the rate of 80- 100/ min. after 15 compressions deliver 2 rescue breats(ratio 15:2). For 2 rescues, the compression-ventilation ratio is 5:1.

. when the help arrives, give 100% oxygen via ambu bag, set up iv line at the antecubital fossa(not at the hand or wrist)- 1000 ml of normal saline should be infused and ECG lead placed. carry on CPR except during intubation and defibrillation. Not more than 30 sec should be allocated for intubation. if intubation fails, restart compressions. once the patient is intubated, ventilations can be given at the rate of 12-15/min, with out pausing for compressions.

. subsiquent management will depend on ECG rythm.

. prepare the following drugs: 10 ml 1;10000 or 1 ml 1;1000 adrenaline, lignocane 100 mg iv, 50 ml bicarbonate 8.4%, isoprenaline 2mg in 500 ml 5% dextrose. If iv access fails , atropine, adrenaline and lignocane can be given via an ETT but double the normal iv dose.

. if the cardiac arrest persisted for more than 30 min, resuscitation is unlikely to b successful. Check the signs of brain death.

. After successful resuscitation, it is important that the patient be monitored carefully. Antiarrythmic agents are necessary in VF or VT. Fluid balance, ABG, CVP, urine out put and electrolytes needed to be mnitored closely and treated appropriately.



B. specific arrest sequences


1. Ventricular fibrillation and pulseless ventricular tachycardia

. Defibrillate 200J. check pulse, recharge, give 15 chest compressions, check monitor.

. defibrillate 200-300J. check pulse, recharge, give 15 chest compressions,
check monitor.

. defibrillate 360J. check pulse, recharge, give 15 chest compressions, check monitor.

. intubation if not already.

. Adrenaline 1 mg iv or ETT or vasopressin 40 U IV, singale dose, 1 time only.

. Defibrillate 360J with in 30-60 sec. check pulse, recharge, give 15 chest compressions, check monitor.

. Administer medications of probable benefit in persistent or recurrent VF/VT.

Medication sequence:

- Amiodarone 150 mg IV (in 100 ml D5%) over 10 min, can be repeated.

- Lignocane 1.0-1.5 mg/kg iv push.repeat 3-5 min to maximum dose of 3mg/kg.

- magnesium sulphate, 1- g IV in refractory VF.

- procainamide 30 mg/min to maximum total dose of 17 mg/kg in refactory VF.



2. Asystole

.CPR

. Adrenaline 1mg IV or ETT

. Intubation if not already

. consider possible causes and initiate appropriate treatment if identified:
hypovolemia, hyper or hypokalemia, hypothermia,hypoxaemia,acidosis, cardiac temponade, tension pneumothorax, pulmonary embolism, drug overdose,acute coronery syndrome.

. consider immediate transcutenious pacing.

. Adrenaline 1 mg IV push, repeat every 3-5 mins.

. Atropine 1mg IV push or 2mg by ETT, repeat every 3-5 mins up to total dose of 0.04mg/kg.

. if no response consider:

- high dose adrenaline regime e.g. 2-5 mg iv push every 3-5 mins or 1mg -3mg - 5 mg IV push (3min apart).

- Consider bicarbonate 50 ml of 8.4% iv.

- Termination of effort.


3. Electromechanical dissociation(EMD).

. CPR

. Adrenaline 1 mg iv push, repeat every 3-5 mins

. intubate if not already

. Atropine 1 mg iv push or 2 mg by ETT. repeat every 3-5 mins up to the total dose of 0.04mg/kg

. Rule out hypovolemia, hyper or hypokalemia, hypoxaemia, hypothermia, acidosis, cardiac temponade, tension pneumothorax,pulmonary embolism, drug over dose, acute coronery syndrome.

. consider:

- pressor agent

- Calcium

- Bicarbonate

- Adrenaline 5 mg iv.

Basic cardiac life support

Basic cardiac life support aims to restore a circulation of oxygenated blood before professional help arrives. It comprises the basic skills of cardiopulmonary resuscitation (CPR) and combines closed chest compression with artificial ventilation of the lungs.

Principles
1. Diagnose cardiac arrest by checking the patient's response to sound and touch, absent respirations and impalpable carotid or femoral pulses.

2. If the arrest is witnessed, consider giving one or two precordial thumps.

3. Assess and clear the airway with the patient on their side. Then position the patient on their back. To prevent obstruction of the upper airway by the tongue, lift the jaw forwards and tilt the head backwards.

4. Occlude the patient's nose and give two breaths into the mouth, or, in small children, into the mouth and nose together. Each breath should last about 1.5 seconds. Do not exhale too vigorously to avoid inflating the stomach. Observe the chest wall rising and falling with each expired air ventilation.

5. Perform external chest compressions:

i. Locate the middle of the sternum by finding the point half-way between the suprasternal notch and the xiphisternum. Compress the chest at or just below this position.

ii. Perform chest compressions at a rate of 80-100 per minute in adults and at least 100 per minute in children and babies.

iii. With each compression, depress the chest wall to a depth of approximately 4-5 cm in adults, 3-4 cm in children and 2-3 cm in babies.

6. The single resuscitator performs 15 chest compressions followed by two exhaled air ventilations. With two operators, cycles comprise 5 chest compressions followed by a pause, during which the lungs are inflated once. These sequences are continued until help arrives.

Advanced cardiac life support

Basic life support maintains viability for only a few minutes. For successful resuscitation, additional advanced cardiac life support is usually required and comprises electrical defibrillation, endotracheal intubation and intravenous drugs and fluids. The principles of management are similar in adults and children. Guidelines on paediatric advanced life support were published in 1996.1
Unless there is immediate return of spontaneous cardiac output, certain `core' interventions are necessary in all cardiac arrests. Additional interventions depend on the specific circumstances of each arrest.

Core management

The `core' interventions in the advanced management of all cardiac arrests are:
A) continued CPR
B) early `blind' defibrillation
C) endotracheal intubation and ventilation of the lungs
D) intravenous fluid loading
E) adrenaline

Early `blind' electrical defibrillation
Direct current (DC) cardioversion improves outcomes when cardiac arrest is due to ventricular fibrillation (VF). It should be performed as soon as the diagnosis of VF is confirmed. In cardiac arrest where the rhythm is in doubt, two or three DC shocks (200, 200 then 360 joules) should be tried `blind'. The interval between each shock should be less than one minute with a check of rhythm being made after each shock.

Endotracheal intubation and ventilation of the lungs
Although not mandatory, endotracheal intubation is the most efficient means of providing artificial ventilation and a cuffed tube may protect the airway from aspiration of gastric contents. It may also be used as a conduit for giving certain drugs, in particular, adrenaline and lignocaine.
In order to correct respiratory acidosis, the lungs should be moderately hyperventilated at a rate of 12-15 ventilations per minute.

Intravenous fluids
An intravenous line should be established at the antecubital fossa (not at the hand or wrist) and 1000 mL of normal saline infused rapidly. Central venous cannulation is not mandatory, but may be required if other venous access cannot be gained. Volume loading is necessary to maintain an adequate venous return to the heart because, during cardiac arrest, there is pooling of blood in venous capacitance vessels and `third space' fluid losses from the vascular compartment. Colloid solutions such as polygeline (Haemaccel) are not usually required. Dextrose solutions are contraindicated as they do not adequately expand the circulation and glucose may be toxic to hypoxic brain cells.

Adrenaline

In adults, current recommendations are for intravenous adrenaline 1 mg (10-15 microgram/kg) to be given immediately and repeated every 3-5 minutes. However, both the American Heart Association and the European Resuscitation Council recognise the theoretical advantages of adrenaline in higher doses (i.e. 100 microgram/kg) if the initial lower dose fails. In adults, this represents 5-10 mg every 5 minutes.
It does not matter whether 1:1000 or 1:10 000 strengths of adrenaline are used if it is injected into an intravenous fluid infusion. The currently available ampoules of either concentration contain 1 mg of adrenaline.

Routes of drug administration
All drugs should be given via the intravenous line with normal saline running. There is no role for intracardiac administration. If there is delay in gaining intravenous access, some drugs, including adrenaline, lignocaine and atropine, may be administered via the endotracheal tube at twice the intravenous dose (however, this is empiric and the bioavailability of drugs given endotracheally is unknown). In young children, the intraosseous route can be used for both fluid and drug delivery and is comparable to intravenous administration.

Management of specific dysrhythmias

The core procedures are continued throughout the management of the arrest. According to circumstances, additional specific interventions are also utilised.

Ventricular fibrillation

This is the commonest rhythm in cardiac arrest. VF can be triggered by acute ischaemia, electrolyte disturbance, hypothermia, hypoxia or electric shock. The ECG shows irregular electrical activity with no discrete P waves or QRS complexes.

DC countershock in ventricular fibrillation
Defibrillation is the only acceptable first-line specific therapy in VF and is the cornerstone of treatment.
Current flow through the heart is optimised by correctly positioning the paddles and reducing transdermal electrical resistance. Usually one paddle is located at the cardiac apex and the other to the right of the upper sternum. However, the operator should visualise a mental picture of the passage of current flow through the heart and should modify the paddle positions accordingly. Firm pressure should be applied to the paddles which should be in good electrical contact with the skin using either conducting gel or special conducting pads. Shocks should initially be at 200 joules, but if the first two or three have been unsuccessful, all subsequent shocks should be at 360-400 joules. For children, use 3-4 joules per kilogram.
Defibrillation is not benign, but as it is the most important therapeutic modality in VF, it should be used repeatedly according to the doctor's judgement.

Drugs in ventricular fibrillation
Drugs are secondary to electrical defibrillation and have limited efficacy. All drugs should be given as boluses, with lignocaine being tried first. Other drugs may be considered subsequently. There should be cycles of at least a further 3 DC shocks and continued CPR for one minute (approximately 10 sequences of 5:1 compression-ventilation) before each new drug is given.

Lignocaine:- There is little (if any) evidence that lignocaine terminates VF and theoretically it may adversely raise the threshold for successful electrical defibrillation. The major effective use for lignocaine is to suppress ectopic ventricular activity once spontaneous circulation has returned. The initial dose is 1.5 mg/kg followed by an infusion of 2-8 mg/minute.

Other antiarrhythmic agents:- In refractory VF which is not responding, other antiarrhythmic drugs may be tried, usually amiodarone (5 mg/kg) or sotalol (1.5 mg/kg). Both these drugs have beta blocking and class III antiarrhythmic activity, but their efficacy in intractable VF remains speculative. Procainamide (class Ia) is occasionally tried (50 mg increments at 5 minute intervals up to 20 mg/kg).

Electrolytes

Magnesium sulphate (5-20 mmol intravenously) may be useful in polymorphic ventricular tachycardia (torsades de pointes), especially when this is secondary to drug toxicity such as tricyclic antidepressants. It may be tried in VF, but there is no evidence of efficacy.

Potassium chloride (5-20 mmol intravenously) raises the threshold for membrane depolarisation. Many cardiac patients are chronically potassium-depleted due to diuretic therapy and this may predispose them to fibrillation. Potassium chloride probably has little effect in intractable VF.

Asystole or agonal bradycardia

Asystole carries a very grim prognosis. If the ECG shows a flat line, quickly check the connections and settings of the ECG monitor to exclude the possibility of instrument malfunction. It is worthwhile switching through the various leads on the monitor as a low amplitude VF in one lead may be misinterpreted as asystole.
Treatment of asystole is maintenance of CPR and repeated adrenaline. There are few specific therapies.
Atropine (1-2 mg) is often given, but probably has little or no effect in cardiac arrest. The dose is not repeated.
Transvenous cardiac pacing may be tried if a temporary pacing wire is immediately available. External transcutaneous pacing is ineffective in asystole.
Adenosine antagonism is a theoretical pharmacological approach. Myocardial accumulation of adenosine has been postulated as contributing to persistent asystole. Aminophylline (250 mg intravenous bolus) is an adenosine antagonist and has been reported to result in spontaneous cardiac output in some patients in asystole not responding to standard therapy. Such claims remain unproven.

Electro-mechanical dissociation (pulseless electrical activity)

Electro-mechanical dissociation is the presence of an electrical rhythm without mechanical cardiac output and may imply that there is little viable or functional myocardium. It may also be associated with profound hypovolaemia, drug toxicity, electrolyte imbalance or mechanical obstruction to cardiac output such as pulmonary embolism, cardiac tamponade or tension pneumothorax.
Along with ongoing CPR and repeated high-dose adrenaline, treatment is obviously directed at correcting any reversible underlying cause. Calcium is not used except in specific circumstances.


The decision to stop treatment

After 10 minutes without a spontaneous output, the chances of a patient surviving long term are very slim. Even in survivors, the probability of profound hypoxic neurological deficit is very high. Cardiac arrest with no return of spontaneous circulation for greater than 20 minutes is usually hopeless and, at this stage, withdrawal of treatment should be considered. Even if cardiac output is eventually restored, virtually none of these patients ever leave hospital. An exception to this general principle is made in the case of a profoundly hypothermic patient - especially in an immersion incident involving a child. In such cases, there have been reports of successful outcomes after protracted resuscitation lasting over an hour.

Conclusion

Cardiac arrest still has a very poor prognosis, although recent advances based on scientific rather than anecdotal principles have increased the possibility of at least short-term survival. The issues of long-term survival and quality of life are unresolved.