CPR in Special Circumstances

The fundamental principles of CPR — oxygenate and circulate — apply in every situation. But the technique must adapt to the patient's size, the cause of arrest, and the physiological context. Applying adult CPR technique to a two-month-old infant will cause injury. Prioritising compressions over ventilation in a drowning victim will cost precious seconds. Understanding these adaptations makes the difference between effective and ineffective resuscitation.

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CPR on an Infant (Under 1 Year)

Infants are not small adults. Their chests are small and flexible, their airways are proportionally larger relative to body size, and the causes of cardiac arrest differ markedly from adults — airway obstruction and respiratory failure precede cardiac arrest far more commonly in infants than cardiovascular disease.

Technique

1. Check responsiveness — flick the sole of the foot firmly. Do not shake an infant.
2. Open airway — head-tilt chin-lift, but use only a neutral or very slight tilt — over-extending an infant's neck can occlude the airway
3. Check for breathing — 10 seconds; look for chest rise
4. Give 5 rescue breaths first — use a mouth-to-mouth-and-nose technique; deliver gentle puffs — enough to see the chest rise, not adult-size breaths
5. Locate compression site — just below the nipple line, centre of chest
6. Use 2-finger technique — place two fingers on the sternum (index and middle finger of one hand); this is adequate for most infants
7. Compression depth — approximately 4 cm (1.5 inches) — about one-third of chest depth
8. Rate — 100–120 per minute
9. Ratio — 30 compressions to 2 rescue breaths for one rescuer; 15:2 for two trained rescuers
10. Allow full recoil between each compression

⚠️ Do NOT tilt an infant's head as far back as you would an adult. A neutral position — ear in line with shoulder — is the correct airway position for an infant. Excessive tilt collapses the soft trachea.

Two-Thumb Encircling Technique (Two Rescuers)

When two trained rescuers are present, the two-thumb encircling technique is preferred for infants: place both thumbs side by side on the sternum, encircle the chest with both hands, and compress using the thumbs. This technique produces superior depth and recoil compared to the two-finger method.

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CPR on a Child (1–8 Years / 25 kg)

Paediatric cardiac arrest is most commonly caused by respiratory failure. This means ventilation is important from the start.

Parameter	Child (1–8 years)	Adult
Initial breaths	5 rescue breaths before compressions	Not required for Hands-Only
Hand position	Heel of one hand, centre of chest	Both hands interlaced
Compression depth	5 cm (2 inches) — one-third of chest depth	5–6 cm
Compression rate	100–120 per minute	100–120 per minute
Ratio (one rescuer)	30:2	30:2
Ratio (two trained)	15:2	30:2
AED	Paediatric pads if available (under 25 kg)	Adult pads

• One or two hands — use one hand for most children; two hands for larger children over approximately 8 years who approach adult size
• Rescue breaths — ensure head-tilt-chin-lift, seal mouth fully, deliver a breath over 1 second to see gentle chest rise

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Drowning — Ventilation Priority

Drowning cardiac arrest is hypoxic arrest — the heart stops because of a prolonged lack of oxygen, not because of a sudden arrhythmia. Defibrillation alone will not resuscitate a hypoxic heart. Oxygen delivery must come first.

Key Differences from Standard CPR

1. Begin with 5 rescue breaths — before starting chest compressions, regardless of patient age
2. Do not delay for AED — retrieve it but start ventilation first
3. Out of the water — begin in-water rescue breaths only if trained to do so; otherwise prioritise rapid removal from water
4. Hypothermia is common — a cold drowning victim may appear dead; do not give up (see below)
5. Vomiting — extremely common during resuscitation of drowning victims; turn head briefly and clear the airway, then continue

The sequence for drowning: 5 rescue breaths → 30 compressions → 2 breaths → continue. If alone with a drowning victim, give 1 minute of CPR before calling emergency services if a phone is not immediately accessible.

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Hypothermia Victim — Never Assume Death

A person who has been submerged in cold water, caught in a blizzard, or left in freezing conditions may appear dead — with no palpable pulse, no visible breathing, fixed and dilated pupils, and rigid limbs. They may still be alive.

The medical principle: "A patient is not dead until they are warm and dead."

Cold dramatically slows all metabolic processes, including the brain's demand for oxygen. Patients have survived prolonged cardiac arrest in cold conditions (cold water immersion, avalanche burial) with full neurological recovery after rewarming.

What to Do

1. Handle gently — rough movement of a hypothermic patient can trigger ventricular fibrillation
2. Check for breathing and pulse for up to 60 seconds — the pulse may be very slow and difficult to feel
3. If no pulse and no breathing — begin CPR
4. Give rescue breaths — the cold slows metabolism; ventilation is especially valuable
5. Do not stop CPR — continue until the patient is rewarmed by medical personnel or you receive medical advice to stop
6. Insulate while doing CPR — prevent further heat loss; CPR-compatible blankets or sleeping bags if available
7. Evacuation — hypothermic cardiac arrest requires hospital rewarming (CPB or ECMO); get to definitive care

⚠️ Do NOT withhold CPR from a hypothermic patient because they appear dead. The outcome cannot be predicted until rewarming is complete. Patients have recovered from core temperatures below 18°C.

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Pregnant Woman — Adapting for Two

Cardiac arrest in pregnancy is rare but requires immediate action for both the mother and unborn child.

Anatomical Considerations

The enlarged uterus compresses the inferior vena cava when the patient is flat on her back, reducing venous return to the heart and reducing the effectiveness of compressions. The diaphragm is elevated, reducing lung capacity.

Modifications

1. Hand position — place hands slightly higher on the sternum than normal (one hand-width above the usual position) to account for diaphragm elevation
2. Left lateral tilt (15–30°) — if possible, place a rolled blanket, bag, or your knee under the patient's right hip to tilt her body approximately 15–30° to the left; this shifts the uterus off the inferior vena cava
3. Uterine displacement — a second rescuer can manually displace the uterus to the left while compressions continue
4. Call for obstetric team — emergency services must be informed that the patient is pregnant; perimortem caesarean section within 5 minutes of cardiac arrest is a recognised intervention in late pregnancy
5. Continue standard CPR and defibrillation — defibrillation is safe for the foetus; the electrical current does not reach the uterus

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Traumatic Cardiac Arrest — Treat the Cause

In traumatic cardiac arrest (following major injury), standard CPR alone is unlikely to be successful unless reversible causes are treated simultaneously.

Reversible Cause	Signs	Treatment
Tension pneumothorax	Absent breath sounds one side, tracheal deviation	Needle decompression (trained only)
Massive haemorrhage	Visible injury, blood loss	Tourniquets, wound packing
Cardiac tamponade	Muffled sounds, distended neck veins	Pericardiocentesis (hospital)
Hypovolaemia	Signs of blood loss	Haemorrhage control

CPR in traumatic arrest should not be abandoned in isolation. Treat haemorrhage, seal open chest wounds, and decompress tension pneumothorax while compressions continue.

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CPR Fatigue — Rotating Rescuers

Effective chest compressions require sustained force. Studies consistently show compression depth and rate deteriorate within 90–120 seconds of starting, even in trained providers who do not perceive fatigue.

Rotation protocol:

• Swap compressors every 2 minutes (roughly one AED analysis cycle)
• Position the next compressor kneeling opposite the current compressor before the swap
• Handoff should take no more than 5–10 seconds
• The departing compressor should call out "Swap now" during the decompression phase
• Verbal count during compressions helps the next rescuer find the rhythm quickly

In a group of bystanders, three rescuers rotating is better than two, and far better than one exhausted individual.

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Quick Reference — Special Circumstances

Situation	Key Modification
Infant < 1 year	Neutral head tilt, 2-finger technique, 4 cm depth, mouth-to-mouth-and-nose, 5 initial breaths
Child 1–8 years	One hand, 5 cm depth, 5 initial breaths, 15:2 with second trained rescuer
Drowning (any age)	5 rescue breaths FIRST, then 30:2; hypoxic arrest — ventilation critical
Hypothermia	Do not assume death; check pulse up to 60 seconds; continue CPR until rewarmed
Pregnant woman	Slightly higher hand position, 15–30° left tilt or manual uterine displacement
Traumatic arrest	Treat reversible causes (haemorrhage, pneumothorax) while doing CPR
Fatigue	Swap compressors every 2 minutes; 5-second handoff maximum

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The Core Principle

Every circumstance that modifies CPR technique is driven by a specific physiological reason. Understanding the reason — hypoxia in drowning, metabolic suppression in hypothermia, caval compression in pregnancy — helps you adapt correctly and confidently when the situation demands it.

No CPR in an unusual situation is ever wasted effort. Imperfect CPR adapted to circumstances will almost always be better than no CPR at all.