Basic Life Support²⁶-Figure 1.

Assess responsiveness Before starting any resuscitation procedure it is vital to evaluate the situation for any danger or physical hazards. The first step in the sequence is to assess the level of responsiveness. Gentle but firm stimulation must be given and this alone may be sufficient to awaken the child or to stimulate respiration. Infants should not be vigorously shaken nor should children with a suspected spinal injury. If the child is unresponsive shout for help. Only move the child if he is in a dangerous location. Airway The tongue is the most common cause of airway obstruction in children. Simple head tilt - chin lift or jaw thrust manoeuvres will establish the paediatric airway, the jaw thrust procedure is particularly recommended when trauma is the cause of the collapse. A recent study has shown that there is no compromise of the airway by hyperextension of the neck32. None the less during trauma the cervical spine should be meticulously guarded by in-line cervical spine immobilisation. If a foreign body is obstructing the airway then it should be removed carefully under direct vision. Blind probing of the child's airway is only likely to impact the object further or to directly cause tissue damage and must be discouraged. When complete upper airway obstruction has occurred as a result of inhalation of a foreign body, the object will probably be too far into the airway to either be seen or removed by simple means and will need advanced airway procedures.

Breathing

Assessing effective breathing is very difficult³³ and is subject to errors. Three methods are recommended in assessing respiration:

1. Look for chest and abdominal movement.
   This detects physical movement, but it may not be co-ordinated and effective in moving air in and out of the lungs.
2. Feel at mouth and nose for air movement.
   This answers the question as to the effectiveness of the chest movement.
3. Listen over the airway for breath sounds.
   An important manoeuvre which will indicate whether the child has large or small airway problems. An absence or lessening of airway noise could mean that the problem is improving; alternatively it could indicate that the child is moving less air past the obstruction and that the situation is getting worse.

If the infant or child is not breathing then it is essential to commence expired air resuscitation immediately. Using the mouth of the rescuer applied to the mouth and nose of the infant has been the conventional teaching but recently the effectiveness of mouth of the rescuer applied to the nose of the infant been described^34,35. In the child, mouth to mouth expired air ventilation is recommended. Because of the probable hypoxic aetiology of the event, five expired air ventilations are considered the optimal number of breaths to oxygenate an infant or a child. The breaths should be slow, each lasting 1 to 1.5 seconds. These slow breaths minimise gastric distension from high pressure, high flow ventilation^36,37. It is also important not to ventilate with excessive tidal volumes as this may lead to gastric distension and regurgitation of gastric contents³⁸. A simple and effective guideline is to observe the child's chest and to stop ventilation when the child's chest looks as if he had taken a deep breath. If the chest does not move when attempting ventilation then reposition the airway or consider clearing the airway using the procedure described below for a choking child.

Circulation

Assessment of the circulation at this point in the resuscitation sequence has conventionally been by checking the pulse. Assessment of the brachial pulse is recommended³⁹ in infants and assessment of the carotid pulse in children.

The pulse check should take no longer than ten seconds and if a pulse is not felt, or the pulse rate is below 60 beats per minute in an infant, then resuscitation should continue immediately with chest compressions. Despite the apparent simplicity of a pulse check, studies have shown that both the lay rescuer and the experienced health care professional have difficulty in making an accurate pulse check^40-43. The inaccuracy of the procedure has led to the validity of a pulse check in paediatric life support being challenged⁴⁴. The concept of not performing a pulse check at all before commencing chest compressions is considered difficult to accept by some as it may appear to be illogical not to formally establish cardiac arrest before commencing chest compressions. Therefore the guidelines now include the statement that starting chest compressions should be considered without delaying for a pulse check in an unresponsive child who does not show obvious signs of recovery after expired air ventilation.

Chest Compressions

Chest compressions (previously known as cardiac massage) are performed on the lower half of the sternum.⁴⁵ In the infant compression is performed using two fingers placed one fingers breadth below an imaginary line joining the nipples. In the child the heel of one hand is used and positioned one finger's breadth up from the xiphisternum. In the older child (over the age of 8) and in the larger young child, this one handed compression technique may be found to be inadequate and the two handed compression technique (as used in adult resuscitation) may be required to produce effective chest compression.

The depth of compression should be judged in relative rather than absolute terms. For infants and small children it is recommended to compress the chest to one third of its resting depth. The efficacy of chest compression can be judged by palpation of the femoral vessels but this may reflect venous and not arterial blood pulsation. More effective assessment can be made by analysis of the arterial waveform or evaluation of the expired carbon dioxide tracing.

The compression rate is 100 compressions per minute. A single expired air ventilation should be given after every five compressions. This provides adequate ventilation and oxygenation for the infant or child. In the older child, where two hands are required for effective chest compression, the adult ratio of 15 compressions to 2 ventilations can be used, compressing the chest at a rate of 100/min.

Activation of the Emergency Medical Services

Ideally the call for help given during the assessment of responsiveness should have activated the emergency medical services. In reality this is not always the case, and the priority in paediatric life support is to establish an airway, to commence effective breathing and to circulate the oxygenated blood. In paediatric life support therefore resuscitation is started and the Emergency Medical Services activated after approximately one minute of resuscitation. Thus the paediatric protocols have adopted the 'phone fast' rather than the 'phone first' philosophy based on the aetiological consideration of resuscitation event. This is considered a general recommendation but local emergency medical services circumstances or the availability of 'dispatcher- guided CPR' may override these recommendations.

Basic life support must continue without further interruption until experienced help arrives or until signs of life return.

Foreign Body Airway Obstruction

Airway obstruction due to aspiration of food or vomit or the inhalation of a foreign body will compromise the paediatric airway. Spontaneous coughing to clear the material should be encouraged but if this fails back blows and chest thrusts in infants and back blows together with alternate cycles of chest thrusts and abdominal thrusts in children may provide vibration to loosen the material and enough expiratory force to expel the obstruction. Abdominal thrusts are not recommended in infants under the age of one year as damage to the abdominal contents may occur. The importance of checking the mouth, formally opening the airway and attempting expired air ventilation after each cycle has been highlighted by the need to ensure that the airway is actually obstructed. These checks are also required to assess whether the clearing manoeuvres have dislodged the material enough to allow some air pass the obstruction. The precise sequence for the relief of airway obstruction has not been formally assessed. 

(Continued ...)

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