Cardiopulmonary Resuscitation

Adult Cardiopulmonary Resuscitation                                       

Introduction

Cardio-respiratory arrest is cessation of mechanical activity of the heart. It is a clinical diagnosis evidenced by unresponsiveness, apnoea or agonal respirations and absence of a detectable central pulse. Immediate and systematic action is essential to prevent death or permanent cerebral damage.

Survival after cardiac arrest out of hospital is extremely low. Coronary artery disease is the commonest cause for sudden cardiac arrest, affecting nearly 700,000 people a year in Europe and one third of people developing a myocardial infarction die before reaching the hospital. The commonest presenting rhythm is rapid ventricular tachycardia or ventricular fibrillation. In the absence of immediate bystander initiated cardio-pulmonary resuscitation this deteriorates to asystole.

In- hospital cardiac arrest occurs in a sicker group of patients and only 20% of them will survive to leave the hospital. The presenting rhythm is either asystole or pulseless electrical activity.

Causes of cardiac arrest

Cardio-pulmonary arrest may occur due to airway obstruction, breathing inadequacy or cardiac abnormalities.

Airway obstruction

• CNS depression
• Blood, vomit, foreign body
• Laryngospasm, bronchospasm
• Trauma
• Infection, inflammation

 

Breathing inadequacy

Decreased respiratory drive

• CNS depression

Decreased respiratory effort

• Neurological lesion
• Muscle weakness
• Restrictive chest defect

Pulmonary disorders

• Pneumothorax, lung pathology

Cardiac abnormalities

Primary

• Ischaemia
• Myocardial infarction
• Hypertensive heart disease
• Valve disease
• Drugs
• Electrolyte abnormalities

Secondary

·         Asphyxia

·         Hypoxaemia

·         Blood loss

·         Septic shock

 

Guidelines for cardio-pulmonary resuscitation

• The first international resuscitation guidelines were published in year 2000 and it represented an important milestone in international collaboration to improve practice and teaching of resuscitation medicine.
• They were formulated after exhaustive review of the published literature and extensive debate at consensus meetings.
• This process was repeated during 2004/2005 led by the International Liaison Committee on Resuscitation (ILCOR) and new guidelines were published as “2005 International Consensus on Cardiopulmonary resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations”.

Diagnosis of cardiac arrest

·   Victim unresponsive and not breathing at all or breathing abnormally (occasional agonal gasps).

 

Checking carotid pulse is unreliable and time-consuming mainly by non-healthcare professionals; therefore time should not be wasted if the victim is unresponsive and apnoeic or breathing abnormally.

If the rescuer is unwilling to perform mouth-to-mouth ventilation, chest compression alone is recommended and it is effective for a limited period (about 5 minutes).

 

Out-of-hospital Resuscitation (Layperson CPR)

Adult Basic Life Support: no equipment available other than a protective device. The purpose of basic life support (BLS) is to maintain adequate circulation and ventilation until the underlying cause for cardiac arrest is reversed. 

Interruptions in chest compressions are associated with a reduced chance of survival. Therefore new guidelines have increased the number of chest compressions given to a victim.

 

Risks to the rescuer: before approaching an apparently unconscious victim, the rescuer must ensure there is no immediate danger from the environment.  

 

Adult BLS sequence

 

1.      Ensure safety of the rescuer and the victim.

2.      Check responsiveness.

3.      If responds, leave in the same position if there is no danger. Reassess regularly and get help if needed.

4.      If no response, call for help; turn onto his back and open the airway using head tilt and chin lift (except in trauma victims).

5.      Look, listen and feel for breathing for no more than 10 seconds.

6.      If breathing normally, turn into the recovery position (lateral with the head

     dependent and no pressure on the chest).

7.      If not breathing normally, start chest compressions. Place the heel of one hand in the centre of the victim’s chest and place the heel of the other hand on top of the first hand. Interlock the fingers; ensure that pressure is not applied over the ribs, upper abdomen or the bottom end of the breastbone. Position vertically above the chest and press down 4-5 cm with straight arms. Press at a rate of about 100 times a minute. Allow the same amount of time for compression and relaxation.  

8.       After 30 compressions give mouth- to-mouth breathing. Continue with chest compressions and rescue breaths in a ratio of 30:2.

9.      Do not interrupt unless the victim starts breathing normally. Rescue breaths should make the chest rise and maintain an open airway.   

 

When to stop BLS?

·         Advanced help arrives

·         The victim starts breathing normally

·         You are exhausted

 

Basic Life Support in hospital setting

 

The same principles apply except that hospitals are usually equipped with basic airway adjuncts such as facemasks, oropharyngeal airways, Ambu bags and source of oxygen.
 

Algorithm for Adult Basic Life Support
 

  In-hospital Resuscitation

 

Cardiac arrest in busy clinical wards occurs in unmonitored patients and usually a period of gradual deterioration of vital signs precedes the cardiac arrest.

 

The Chain of Survival

The actions that contribute to a successful outcome after a sudden cardiac arrest are called the Chain of Survival. There are four links of which all must be strong.

 

1. Early recognition of the patient at risk of cardiac arrest and activation of the emergency services
2. Early CPR
3. Early defibrillation
4. Early advanced life support and effective post resuscitation care

 

Early recognition and prevention of in-hospital cardiac arrest

1. Patients who are critically ill or at risk of clinical deterioration should be monitored in a high dependency unit or an intensive care unit.

2.  Patients at risk of clinical deterioration should be regularly monitored using simple vital sign observations (pulse, blood pressure, respiratory rate).

3.  Use an Early Warning Score system to identify patients at risk of cardiac arrest. There should be a clearly defined response to critical illness. A medical emergency team should be organized to respond in life-threatening events or to advise if condition is deteriorating.

4.   All staff should be educated to recognize, monitor and manage critically ill patients.

5.   Patients who do not wish to receive CPR and those for whom cardiac arrest is an anticipated event should be identified and decision not to resuscitate should be taken prior to cardiac arrest.

6.   Audit all cardiac arrests, false arrests, unexpected deaths and unanticipated intensive care unit admissions.

Algorithm for in-hospital resuscitation

Adult Advanced Life Support
 

The key link in the chain of survival is early defibrillation.

The defibrillator should be attached as soon as possible to identify the rhythm.

The use of adhesive electrode pads or the ‘quick look’ paddles technique will enable rapid assessment compared with attaching ECG electrodes.

Arrhythmias associated with cardiac arrest are divided into two groups:

1. Shockable rhythms (VF/ Pulseless VT)
2. Non-shockable rhythms (asystole and Pulseless Electrical Activity previously Electromechanical Dissociation)

The main difference in the management is the need for defibrillation for VF/VT.

Chest compression, airway management and ventilation, venous access and administration of epinephrine (adrenaline) and identification and correction of reversible factors, are same for both groups.

 

Precordial thump

If the defibrillator is not immediately available consider giving a single precordial thump after confirmation of VF/VT. 

 

Defibrillation

• The new guidelines recommend a single shock only when compared to three shocks in the previous guidelines.
• This recommendation is based on the fact that interruptions to chest compressions for ventilation or analysis of rhythm and delivery of three shocks are associated with reduced survival.
• Modern defibrillators are biphasic and they are available in some of the government hospitals.
• As they are highly efficient, a single shock has a success rate exceeding 90%. The initial shock should be at least 150 J. Give second and subsequent shocks at 150 -360J.
• Refer to the manufacturer’s advice for the exact energy recommended.
• More common version of old defibrillators available in our hospitals is monophasic. As they have a lower efficacy, the recommended energy level for the initial shock is 360J.

Fine VF- The new guidelines do not recommend defibrillation if there is doubt whether the rhythm is asystole or fine VF.

In such case chest compressions and ventilation should be continued.  

 

Use of oxygen during defibrillation:

Sparks from poorly- applied defibrillator paddles can cause a fire when the atmosphere is rich of oxygen. Therefore oxygen delivering tubes should be removed to at least 1 m away from the patient’s chest.  Self-adhesive pads minimise the risk of sparks but they are expensive and not available in most of the government hospitals.

 

Adult Advanced Life Support Algorithm

 

Sequence of actions in Adult Life Support

 

1. Shockable rhythms (VF/VT)

• Attempt defibrillation – one shock only (biphasic  150-200 J or monophasic 360 J).
• Do not check rhythm or pulse, resume CPR immediately after shock.
• Continue CPR for 2 minutes (30:2); then stop briefly to check rhythm.
• If VF/VT persists give a further shock (150-360 J biphasic or 360 J monophasic). Resume CPR immediately, continue for 2 minutes and check rhythm.
• If VF/ VT still persists give adrenaline 1 mg IV followed immediately by a 3^rd shock of above energy. Recommence CPR and continue for another 2 minutes and check rhythm.
• If VF/VT persists after 3^rd shock, give amiodarone 300mg and give a 4^th shock immediately after the drug. Resume CPR for 2 minutes. Adrenaline should be given immediately before alternate shocks: every 3-5 minutes.

( Drug- Shock- CPR- rhythm check sequence).

• As chest compressions are tiring, the provider should be changed every 2 minutes.
• Pulse check : only if a normal ECG rhythm is seen. Start post-resuscitation care in that case.
• If no pulse present with a normal looking ECG or asystole is present, switch to the non-shockable algorithm.

2. Non-shockable rhythms  (Asystole / Pulseless Electrical Activity)

• Start CPR 30:2 until airway is secured.
• Give adrenaline 1 mg IV as soon as IV access is available.
• Continue compressions at 100/minute and ventilation 10/minute once airway is secured without pauses.
• After 2 minutes check rhythm and continue CPR if no change. If changed to VF/VT follow algorithm for shockable rhythms.
• Give adrenaline every other loop (3-5minutes).
• If a normal ECG is seen, check for pulse and proceed accordingly.
• Give atropine 3 mg once only for asystole and pulseless electrical activity with a rate less than 60/minute.
• If there are p waves seen with an apparent asystole, the patient may respond to pacing.

Potentially reversible causes of cardiac arrest

See the box in the algorithm. CPR will not be successful unless these conditions are recognised and treated promptly during management of cardiac arrest.

Post resuscitation care – therapeutic hypothermia

This phase begins with return of spontaneous circulation.

The final outcome from cardiac arrest significantly depends on interventions in this period.

The patients should be monitored and treated in an intensive care unit.

It is recommended to cool unconscious adult patients with spontaneous circulation after out-of-hospital VF cardiac arrest to 32-34⁰ C for 12-24 hours.

These patients who present with a non-shockable rhythm and also patients who arrest in hospital may also be benefited by mild hypothermia.

Venous access and drugs in CPR

Peripheral access is easier and quicker. All drugs must be flushed with at least 20 ml of fluid. Consider intraosseous access for both children and adults. The marrow can be sent for venous blood gas analysis and measurement of electrolyte, blood sugar and haemoglobin. Tracheal route is the least desirable one. The dose of adrenaline is 3 mg diluted to at least 10 ml with sterile water.

Adrenaline

The mechanism of action of adrenaline in CPR is the alpha-adrenergic actions leading to vasoconstriction which results in an increase in cerebral and myocardial perfusion. The dose is 1 mg 1:10,000.

Atropine

Atropine increases sinus automaticity and facilitates AV node conduction. The dose is 3 mg IV once only for asystole and PEA with a rate < 60/min.

Amiodarone

This is indicated if VF/VT persists after 3 shocks. A bolus of 300 mg should be given immediately prior to the 4^th shock. A further dose of 150 mg may be given for refractory or recurrent shock, which should be followed by an infusion of 900 mg over 24 hours.

Lignocaine

This can be used as an alternative to amiodarone, which is available in Sri Lanka but not in all peripheral hospitals. The dose is 1mg/kg. Combination of amiodarone and lignocaine must be avoided due to severe myocardial depression.

Bicarbonate

Routine administration is not recommended. It is indicated if arrest is associated with hyperkalaemia and in tricyclic antidepressant overdose. The dose is 50 mmol. Repeat doses may be given according to the clinical condition and the blood gas analysis.

Magnesium

Indicated in hypomagnesaemia (potassium-losing diuretics), VT with possible hypomagnesaemia, torsade de pointes and digoxin toxicity. The dose is magnesium sulphate 8 mml (4 ml of 50%) 

Calcium

Indicated in PEA due to hyperkalaemia, hypocalcaemia, overdose of calcium channel blockers and magnesium. The dose is 10 ml of 10% calcium chloride and should not be mixed with bicarbonate.

 

Resuscitation in pregnancy 

 

Early detection and prompt attention is the key to prevent a maternal cardiac arrest.  Significant physiological changes occur during pregnancy, e.g., cardiac output, blood volume, minute ventilation and oxygen consumption all increase. Furthermore, the gravid uterus may cause significant compression of iliac and abdominal vessels when the mother is in the supine position, resulting in reduced cardiac output and hypotension. All these factors make it extremely difficult to save the mother and the baby if a cardiac arrest occurs in a pregnant woman. 

Modifications to guidelines for cardiac arrest

·  The gravid uterus reduces the effectiveness of chest compressions. The patient should be positioned in 15 degrees of left lateral decubitus position by manual or mechanical means.

·  A hand position higher than the normal position for chest compression may be needed to adjust for the elevation of the diaphragm and abdominal contents.

·  Defibrillation energy is standard and there is no evidence showing harmful effect on the fetal heart. Placement of paddles may be more difficult due to left lateral tilt and large breasts. Adhesive defibrillator pads are preferable to paddles in pregnancy.

·  Early tracheal intubation with correctly applied cricoid pressure to avoid pulmonary aspiration of gastric contents. This may be more difficult and help from an anaesthetist is advisable.

Specific causes of cardiac arrest in pregnancy

1.  Haemorrhage

2.  Pre-eclampsia and eclampsia

3.  Cardiovascular disease

4.  Life-threatening pulmonary embolism

5.   Amniotic fluid embolism

6.   Drugs (magnesium toxicity, local anaesthetic toxicity in regional anaesthesia)

If immediate resuscitation attempts fail:

·   Consider the need for an emergency hysterectomy or Caesarean section if CPR is unsuccessful after 5 minutes.