In-hospital arrest

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Florence Yap & Katherine Lam

The outcome of in-hospital cardiac arrest is very poor. The goal of treatment should always be to intervene early before the patient deteriorates to cardiopulmonary arrest.

Who should be resuscitated?

CPR should only be carried out in patients who have a reasonable chance of benefiting from it.
Should not be carried out in those patients who are expected to die or in whom cardiac arrest is the final stage of a gradual progressive deterioration.
Whether cardiopulmonary resuscitation should be carried out should be considered for each patient and should be reviewed on a regular basis. The decision not to attempt cardiopulmonary resuscitation should only be made in consultation with a senior doctor. Factors to consider include:
- premorbid status
- underlying illness
- life expectancy
- quality of life
- patient’s wishes
Resuscitation status should be discussed with patient, family and/or surrogate. “Do not attempt cardiopulmonary resuscitation orders” should be clearly documented along with the rationale for the decision.

It should also be clearly understood that this order refers only to resuscitation in the event of a cardiac arrest and that all other care and treatment should be continued.

To read a discussion of ethics related to do not attempt resuscitation orders click here.

Potentially reversible causes for cardiac arrest

Hypovolaemia
Hypoxia
Electrolyte disturbance, particularly hyper- or hypokalaemia
Acidosis
Tension pneumothorax
Cardiac tamponade
Acute coronary syndrome
Pulmonary embolus
Hypothermia
Poisoning

Management of cardiopulmonary arrest

Figure 1. Algorithm for managing cardiac arrest, adapted from ILCOR guidelines. Note that it is only necessary to check the pulse after checking the rhythm if the patient has a potentially perfusing rhythm (ie NOT asystole or VF).

A number of key issues need to be remembered:
- Management decisions are based on whether the patient is in a VF/VT rhythm or a non-VF/VT rhythm.
- The most effective treatment for VF/VT is defibrillation
- Early defibrillation results in better outcomes and should not be delayed by an attempt to gain intravenous access, secure the airway or perform cardiac compressions. However cardiac compressions and ventilation should be started if a defibrillator is not immediately available
- Minimize any interruption to cardiac compressions

Basic CPR

Early basic CPR contributes to preservation of heart and brain function and improves survival.
Recommended chest compression rate is at least 100/min (rather than 80-100) and is the same for adults and children.
Allow full chest recoil in between compressions: during each compression the actual compression time should be 50% with the other 50% being used to allow recoil.
Always minimize interruption to chest compression.
Compression-ventilation ratio should be 30:2 before intubation regardless of the number of rescuers. After intubation, ventilate at a rate of 8 to 10 breaths per minute without synchronizing with chest compression. Avoid hyperventilation.

During cardiac massage and ventilation check the electrode or paddle positions and contact, secure the airway and obtain intravenous access. None of these procedures should delay defibrillation in patients with VF/VT.
Reversible causes for cardiac arrest should be sought and corrected.

Defibrillation

The most ‘resuscitatable’ rhythm (with the highest rate of hospital discharge) is VF.
VF is also the most frequent initial rhythm in witnessed sudden arrests.
The most effective treatment for VF is defibrillation. Probability of successful defibrillation decreases with time, 7-10% per min, and VF tends to convert to asystole within a few minutes. Early defibrillation is, therefore, the goal and this is reflected in the resuscitation algorithm.
One shock strategy is preferable to the previously recommended 3-shock sequence, with minimal interruption to chest compressions. For conventional monopolar defibrillator, use 360J for the first shock and the subsequent shocks.

Biphasic Defibrillation

Compared to conventional monophasic defibrillation, this uses less energy to generate the same current flow through the heart, and results in less myocardial injury.
At least as successful for VF termination compared to monophasic shocks.
Optimal energy for biphasic defibrillation is uncertain. The recommended energy for biphasic defibrillation varies with different manufacturer and different energy waveform and may range from 120J to 360J.
Studies comparing fixed versus escalating energy for biphasic defibrillation did not identify a clear benefit for either strategy. Both can be used safely and effectively.

Medications

Drugs are always of secondary importance to basic CPR, defibrillation, and proper airway management.

Agents to optimise cardiac output and perfusion pressure

Epinephrine

Standard dose is 1 mg every 3-5 min
High dose epinephrine (up to 0.2mg/kg) may improve return of spontaneous circulation, but studies have shown no improvement in long term survival / neurological outcome. Retrospective studies have suggested that it could be associated with worse hemodynamic and neurological outcomes.

Vasopressin

Naturally occurring vasoconstrictor
Half-life of 10-20 minutes
Causes intense vasoconstriction in skin, skeletal muscle, intestine and fat tissues, and less intense vasoconstriction in the coronary and renal circulation. Vasopressin causes vasodilation in the cerebral circulation.
Despite promising lower level data and well performed animal studies, 2 large randomized control trials of adults in cardiac arrest were unable to show an increase in the rates of return of spontaneous circulation (ROSC) or survival for vasopressin when compared with adrenaline as the initial vasopressor. A meta-analysis of 5 randomized controlled trial show no statistically significant difference between vasopressin and epinephrine for ROSC, death within 24 hours or death before hospital discharge. Hence, there is insufficient evidence to support or refute the use of vasopressin as an alternative, or in combination with, epinephrine in any cardiac arrest rhythm.

Anti-arrhythmics

Defibrillation is more effective than anti-arrhythmic therapy and at least 3 shocks should be given before anti-arrhythmics are considered.

Amiodarone

Recommended for unstable, shock-resistant VF/VT or recurrent VF/VT.
300mg over l0mins, then 60mg/hr for 6 hrs, then 30mg/hr (total 2 g/day).

Lignocaine

Not recommended because of paucity of evidence to support its efficacy.

Teamwork

Successful resuscitation requires team work. It is related to the interactions, knowledge, and skills of responders.
There should be a team leader who is responsible for assessment /evaluation of the situation and delegation of duties. Other responders should accept the delegated role and stay focused, while remaining aware of evolving resuscitation activities.
Delegated duties include:

defibrillation

airway management

chest compressions with relief person (rotate person performing compressions each time rhythm is checked)

intravenous access

drug administration

recording and documentation

notifying attending physician and family

Management of survivors of cardiac arrest

Treat the underlying cause eg thrombolysis / percutaneous coronary intervention for myocardial infarction, renal replacement therapy for severe hyperkalaemia
Organ support
Treat seizures
Valproate and clonazepam are the preferred anticonvulsants for myoclonus
Consider midazolam or propofol to rapidly terminate generalized convulsions and phenytoin to prevent recurrence.
Blood glucose control
Several human studies have demonstrated a strong association between high blood glucose after resuscitation from cardiac arrest and poor neurological outcome
Monitor blood glucose level, treat hyperglycaemia with insulin but avoid hypoglycaemia
Consider continuous EEG monitoring, especially if patient is sedated and/or paralysed
Cerebral protection with hypothermia

Resuscitation of potentially infectious patients

Cardiopulmonary resuscitation of patients with diseases spread via respiratory secretions is a high risk procedure because of the high risk of contamination of personnel by body fluids, respiratory droplets and aerosols

Practical tips:

Put on appropriate personal protective equipment (PPE) eg N95 mask, full face shield, protective gowns, gloves
A high efficiency bacterial-viral filter should be added to the resuscitator bag to form a bag-valve-filter-mask assembly (figure 2).

Figure 2. Bag-valve-filter-mask assembly for manual ventilation of potentially infectious patients.

Use a 2 person technique where possible for manual ventilation to ensure air-tight seal. One person holds the mask with two hands while the other squeezes the bag (figure 3).

For intubation, minimize coughing and spluttering with appropriate sedation/paralysis and ensure all is equipment ready before the procedure
Place contaminated equipment onto tray/incontinence pads to prevent contamination of the surroundings
Health care workers should wash hands, remove contaminated PPE, and take a shower shortly after the resuscitation.
Instruments should be properly disposed of or disinfected
The environment should be properly cleaned and disinfected.