Resuscitation
Question 173 of 180
A 32 year old man is brought to the Emergency Department (ED) at 04:00. It is December and the outside temperature is -4°C. He was found unconscious in a neighbours garden and appears to have been drinking alcohol, he was last seen at 22:00. Paramedics could not find a central pulse and have commenced CPR. They have recorded a bradycardic PEA throughout transfer to ED. On arrival the patient is still in cardiac arrest and a core temperature of 26°C is recorded. The rhythm strip shows ventricular fibrillation. Which of the following defibrillation strategies is recommended?
Answer:
- If VF is detected, defibrillate according to standard protocols; if VF persists after 3 shocks, delay further attempts until core temperature is ≥ 30°C; CPR and rewarming may have to be continued for several hours to facilitate successful defibrillation
Resuscitation in Special Circumstances
Resuscitation
Last Updated: 20th December 2022
Cardiac arrest associated with hyperkalaemia
Modifications to resuscitation associated with severe hyperkalaemia:
- Confirm hyperkalaemia using a blood gas analyser
- Protect the heart:
- Give 10 mL calcium chloride 10% IV by rapid bolus injection
- Shift potassium into cells
- Give 10 units short-acting insulin and 25 g glucose IV by rapid injection; monitor blood glucose
- Give sodium bicarbonate
- Give 50 mmol IV sodium bicarbonate by rapid injection (if severe acidosis or renal failure)
- Remove potassium from the body
- Consider dialysis for hyperkalaemic cardiac arrest resistant to medical treatment
Cardiac arrest occurring during haemodialysis
Sudden cardiac death is the most common cause of death in haemodialysis patients and is usually preceded by arrhythmia.
Modifications to resuscitation during dialysis:
- Call resuscitation team and seek expert help immediately
- Start resuscitation according to standard ALS protocols
- Assign a trained dialysis nurse to the dialysis machine, stop ultrafiltration and give a fluid bolus, return the patient's blood volume and disconnect from the dialysis machine
- Leave dialysis access open and use for drug administration
- Minimise delay in delivery defibrillation; VF/pVT is more common in dialysis patients than in the general population; disconnect from the dialysis equipment prior to defibrillation if recommended by manufacturer
- All of the standard reversible causes apply to dialysis patients; electrolyte disorders, particularly hyperkalaemia, and fluid overload are the most common causes
Cardiac arrest associated with poisoning
Modifications to resuscitation associated with poisoning:
- Ensure your personal safety and wear appropriate personal protective equipment
- Avoid mouth-to-mouth breathing in the presence of chemicals such as cyanide, hydrogen sulphide, corrosives and organophosphates
- Treat life-threatening tachyarrhythmias with cardioversion, according to the peri-arrest arrhythmia guidelines; this includes correction of electrolyte, glucose and acid-base abnormalities
- Once resuscitation has started, try to identify the poison; relatives, friends and ambulance crews may provide useful information; examination of the patient may reveal diagnostic clues e.g. odours, needle marks, pupil size, signs of mouth corrosion
- Measure the patient's temperature because hypo- or hyperthermia may occur in drug overdose
- Provide standard basic and advanced life support if cardiac arrest occurs
- Be prepared to continue resuscitation for a prolonged period of time, particularly in young patients, as the poison may be metabolised or excreted during prolonged attempts; consider extracorporeal life support (ECLS)
- Seek local expert advice and consult a regional or national poisons centre for information on treatment of the poisoned patient
Cardiac arrest associated with asthma
Patients most at risk of asthma-related cardiac arrest include those with:
- a history of near-fatal asthma requiring intubation and mechanical ventilation
- hospitalisation or emergency care for asthma in the past year
- low or no use of inhaled corticosteroids
- increasing use and dependence on β2-agonists
- anxiety, depressive disorders and/or poor compliance with therapy
- a history of food allergy in addition to asthma
Causes of cardiac arrest associated with asthma include:
- Severe bronchospasm and mucous plugging leading to asphyxia
- Cardiac arrhythmias caused by hypoxia (or by treatment drugs e.g. β2-agonists or electrolyte abnormalities)
- Dynamic hyperinflation (auto positive end-expiratory pressure (auto-PEEP)) in mechanically ventilated patients; air trapping and 'breath-stacking' causes gradual build up of pressure leading to decreased venous return and blood pressure
- Tension pneumothorax (may be bilateral)
Modifications to resuscitation associated with asthma:
- Follow standard BLS and ALS protocols; ventilation will be difficult because of increased airway resistance; try to avoid gastric inflation
- Intubate the trachea early; there is significant risk of gastric inflation and hypoventilation of the lungs when attempting to ventilate a severe asthmatic without a tracheal tube
- Follow the recommended respiratory rate of 10 breaths/min and tidal volume required for a normal chest rise during CPR (to avoid gas trapping and dynamic hyperinflation)
- If dynamic hyperinflation of the lungs is suspected during CPR, compression of the chest wall and/or a period of apnoea (disconnection of tracheal tube) may relieve gas trapping
- Dynamic hyperinflation increases transthoracic impedance but modern defibrillators are no less effective in patients with higher impedance; as with standard ALS protocol, consider increasing defibrillation energy if the first shock is unsuccessful
- Look for reversibles causes using the 4Hs and 4Ts
- Tension pneumothorax can be difficult to recognise during cardiac arrest; it may be indicated by unilateral expansion of the chest wall, shifting of the trachea and subcutaneous emphysema; pleural ultrasound in skilled hands is faster and more sensitive than chest x-ray for detection; early needle decompression followed by chest drain insertion is needed; thoracostomy may be quicker and more effective in the ventilated patient; always consider bilateral pneumothoraces in asthma-related cardiac arrest
- Extracorporeal life support (ECLS) can provide both organ perfusion and gas exchange in cases of otherwise refractory respiratory and circulatory failure
Cardiac arrest associated with anaphylaxis
Modifications to resuscitation associated with anaphylaxis:
- Start CPR immediately and follow current guidelines
- Prolonged CPR may be necessary
- Cardiac arrest with suspected anaphylaxis should be treated with the standard 1 mg dose of IV or IO adrenaline for cardiac arrest; if this is not feasible, consider 0.5 mg IM adrenaline if cardiac arrest is imminent or has just occurred
Cardiac arrest in pregnancy
- See separate article
Cardiac arrest in trauma
- See separate article
Cardiac arrest associated with drowning
Modifications to ALS after drowning:
- Airway and breathing
- Give high flow (10 - 15 L/min) oxygen, ideally through a oxygen mask with a reservoir bag to the spontaneously breathing patient
- Consider early tracheal intubation and controlled ventilation for victims who fail to respond to initial basic airway measures, who have a reduced level of consciousness or are in cardiac arrest (reduced pulmonary compliance requiring high inflation pressures may limit the use of a supraglottic airway device)
- In a patient who has not arrested or who has achieved ROSC, titrate the inspired oxygen concentration to achieve SpO2 of 94 – 98%; confirm adequate oxygenation and ventilation with arterial blood gases once available; set PEEP to at least 5 – 10 cm H2O (PEEP values of 15 - 20 cm H2O may be required if the patient is severely hypoxaemic; decompress the stomach with a gastric tube
- Circulation and defibrillation
- Palpation of a pulse as a sole indicator of cardiac arrest is not always reliable, particularly in the wet and cold drowning patient; as soon as possible check the ECG and end-tidal CO2 to confirm presence or not of a cardiac output
- If the victim is in cardiac arrest, follow standard ALS protocols; if the patient is hypothermic, modify the approach for treatment of hypothermia
- Assess the rhythm and attempt defibrillation if indicated according to standard protocols; dry the victim's chest before applying defibrillator pads
- After prolonged immersion, most victims will have become hypovolaemic due to the cessation of the hydrostatic pressure of water on the body; give rapid IV fluid to correct hypovolaemia commenced out of hospital if transfer time is prolonged
- Discontinuing resuscitation efforts
- Making a decision to discontinue resuscitation efforts on a victim of drowning is difficult; no single factor predicts good or poor survival
- Continue resuscitation unless there is clear evidence that such attempts are futile (e.g. massive traumatic injuries, rigor mortis), or timely evacuation to a medical facility is not possible
- Neurologically intact survival has been reported in several victims submerged for longer than 25 min, however these case reports almost invariably occur in children submerged in ice-cold water
- Post-resuscitation care
- Follow standard post-resuscitation guidelines
- Many victims of drowning are at risk of developing acute respiratory distress syndrome (ARDS) and standard protective ventilation strategies for ARDS should be followed
- Extracorporeal membrane oxygenation (ECMO) has been used for those in refractory cardiac arrest, those with refractory hypoxaemia and in selected cases of submersion in ice cold water
- Pneumonia is common after drowning; consider prophylactic antibiotics after submersion in grossly contaminated water such as sewage
- Neurological outcome is primarily determined by the duration of hypoxia
Cardiac arrest associated with hypothermia
Modifications to resuscitation in the hypothermic patient:
- Check for signs of life for up to 1 minute; palpate a central artery and assess the cardiac rhythm; if there is any doubt, start CPR immediately
- Hypothermia can cause stiffness of the chest wall making ventilation and chest compressions difficult; consider the use of mechanical chest compression devices
- Do not delay careful tracheal intubation where indicated; the advantages of adequate oxygenation and protection from aspiration outweigh the minimal risk of triggering VF by performing tracheal intubation
- Once CPR is underway, confirm hypothermia with a low-reading thermometer
- The hypothermic heart may be unresponsive to cardioactive drugs, attempted electrical pacing and defibrillation; drug metabolism is slowed leading to potentially toxic plasma concentrations of any drugs given; it is reasonable to withhold adrenaline and other CPR drugs until the patient has been warmed to a core temperature of ≥ 30°C; once 30°C has been reached, the intervals between drug doses should be doubled when compared to normothermia (i.e. adrenaline every 6 - 10 minutes, until reaching ≥ 35°C where standard drug protocols should be used)
- Treatment of arrhythmias associated with hypothermia
- As core temperature decreases, sinus bradycardia tends to give way to atrial fibrillation followed by VF and finally asystole
- Arrhythmias other than VF tend to revert spontaneously as core temperature rises and usually do not require immediate treatment
- Cardiac pacing is not indicated in bradycardia in severe hypothermia unless it is associated with haemodynamic compromise which persists after rewarming
- If VF is detected, defibrillate according to standard protocols; if VF persists after 3 shocks, delay further attempts until core temperature is ≥ 28 – 30°C; CPR and rewarming may have to be continued for several hours to facilitate successful defibrillation
Cardiac arrest associated with hyperthermia
Modifications to resuscitation in the hyperthermic patient:
- The mainstay of treatment is supportive therapy based on optimising the ABCDEs and rapidly cooling the patient
- Start cooling before the patient reaches hospital; aim to rapidly reduce the core temperature to approximately 39°C; patients with severe heat stroke need to be managed in a critical care setting
- Use haemodynamic monitoring to guide fluid therapy; large volumes of fluid may be required; correct electrolyte abnormalities
- If cardiac arrest occurs, follow standard procedures for basic and advanced life support and cool the patient; provide post-resuscitation care according to normal guidelines
Cardiac arrest associated with lightning strike and electrical injury
Modifications to resuscitation following electrical injury or lightning strike:
- Ensure any power source is switched off and do not approach the victim until it is safe
- High voltage electricity can arc and conduct through the ground for up to a few metres around the victim
- It is safe to approach and handle casualties after lightning strike although it would be wise to move to a safer environment
- Follow standard resuscitation guidelines
- Airway management can be difficult if there are electrical burns around the face and neck; intubate the trachea early in these cases and soft tissue oedema can cause subsequent airway obstruction; consider cervical spine immobilisation but this should not delay airway management
- Muscular paralysis, especially after high voltage, may persist for several hours; ventilatory support is required during this period
- VF is the commonest initial arrhythmia after high voltage AC shock; treat with prompt attempted defibrillation
- Asystole is more common after DC shock; use standard guidelines
- Remove smouldering clothing and shoes to prevent further thermal injury
- Give IV fluids if there is significant tissue destruction; maintain a good urine output to increase excretion of myoglobin, potassium and other products of tissue damage
- Consider early surgical intervention in patients with severe thermal injuries
- Conduct a thorough secondary survey to exclude injuries cause by tetanic muscular contraction or from the person being thrown by the force of the shock
- Electrocution can cause severe, deep soft tissue injury with relatively minor skin wounds because current tends to follow neurovascular bundles; look carefully for features of compartment syndrome, which will necessitate fasciotomy
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
