Advanced Life Support²⁷ - Figure 2

The Basic Life Support sequence provides the fundamental primary treatment of an infant or child that collapses in cardiopulmonary arrest. Advanced life support is the definitive management of the condition using complex techniques, drugs and equipment. As in basic life support, advanced life support protocols emphasise the importance of establishing an airway, oxygenation and ventilation from the outset. Although it includes a pathway for the management of ventricular fibrillation (VF) and ventricular tachycardia (VT) the emphasis is on non-ventricular fibrillation and non-ventricular tachycardia (Asystole and Pulseless Electrical Activity - previously known as Electro-Mechanical Dissociation) as these are the rhythms found in the majority of paediatric events. Ventricular fibrillation has been documented in less than 10% of paediatric events6,9,10,46-48.

Airway

The simple basic procedures of head-tilt, chin lift or jaw thrust remain the mainstay of airway management. The insertion of a Guedel airway, correctly sized from the centre of the mouth to the angle of jaw, may be of use to aid simple airway control in the short term. Alternatively a nasal airway can be inserted.

The laryngeal mask airway has been assessed as an effective airway adjunct in adult resuscitation and is a technique that can easily be taught to doctors, nurses and paramedic staff^49-54. Small sized laryngeal masks are available for infants and children but their effectiveness in paediatric resuscitation has yet to be established. They will probably have their most significant effect where intubation is difficult or where the health care provider is not proficient in paediatric tracheal intubation skills.

Tracheal intubation is the most effective method of securing the paediatric airway. Using a straight bladed laryngoscope and a plain plastic tracheal tube of the appropriate size (internal diameter (mm) = (age in years /4) + 4) is a technique which requires a skill only developed by formal training and regular practice. Intubation must be achieved quickly and accurately without a prolonged delay to basic life support. Any attempt lasting longer than 30 seconds should be abandoned and the child reoxygenated before a further attempt at intubation is made. Having achieved tracheal intubation the tracheal tube needs to be carefully fixed in place to prevent its accidental removal or displacement.

Oxygenation

Although expired air resuscitation will provide some oxygenation the sooner ventilation with high-inspired oxygen levels can be established the better. Ventilation using a self-inflating bag-valve-mask with supplemented oxygen will provide higher levels of inspired oxygen. Concentrations up to 90% can be achieved if the self-inflating bag is fitted with an oxygen reservoir system. Face masks for use with a self inflating bag should be of clear plastic so that the airway can be observed through the mask and the circular design mask with a soft seal rim have been found to be most efficient, especially in the hands of an inexperienced operator. Although many anaesthetists are experienced in the use of the Ayre's T-piece with the Jackson-Reece modification for paediatric ventilation, this circuit is not recommended for the less experienced and should not be part of the routine resuscitation equipment. Furthermore this system requires a constant flow of oxygen which may not always be immediately available. The self-inflating resuscitation bag can function independently and has the advantage of being capable of being operated safely and effectively by a much wider range of operators.

Circulation

There are few procedures more fraught with difficulty in resuscitation than establishing venous access in an infant or small child during resuscitation. Yet circulatory access is of prime importance to effective advanced life support^55,56. The intravenous or intraosseous routes of drug delivery are the preferred options. The site of venous access has to be balanced against the resuscitation skills and relative difficulty and risks of the technique. Experimental data has demonstrated that vascular access via the superior vena cava by either peripheral or central routes is preferable during resuscitation^57-59. Drugs given via the inferior vena cava take longer to reach the heart^58,59. Similarly drugs administered centrally do act more rapidly than those administered via the peripheral route^58,60-62. Central access above the diaphragm is difficult and fraught with potential problems. Peripheral access, especially via veins in the lower limbs is usually easier especially during resuscitation. Drugs administered via the peripheral route should be followed by a fluid flush to move more rapidly into the actual circulation. Therefore when judging the advantages of the different access points and deciding which to select it must be remembered that achieving access accurately safely and rapidly is the first priority.

Intraosseous access has gained popularity in the last few years - see  Venous Cutdown and Intraosseous Infusion, Update in Anaesthesia 1995;5:3. It is relatively easy and generally safe. Resuscitation drugs and fluids administered by this route reach the heart in a time comparable to direct peripheral venous access^64-67. Although originally recommended for children under the age of six the intraosseous route has been used in older age groups and in adults during cardiac resuscitation^67,68. When establishing intraosseous access it is important to recognise the criteria for successful entry into the bone marrow. There should be a loss of resistance as the marrow cavity is entered, the needle should remain upright without support, bone marrow can be aspirated with a syringe and there is free flow of drugs and fluid without subcutaneous infiltration around the entry point^69,70. Marrow aspirates can be used for estimation of haemoglobin, sodium, potassium, chloride and glucose⁷¹. Complications of intraosseous access include osteomyelitis, long bone fractures⁷², subcutaneous drug extravasation and compartment syndrome^75-77.

The tracheal route of administration of drugs comes third to the intravenous and the intraosseous routes. It is best regarded as a route to be used where there has been, or is likely to be, a significant delay in establishing venous access and thus the administration of drugs. Therefore during resuscitation of the small infant or child it could be argued that the first important dose of adrenaline should be given by the tracheal route whilst venous access is being established^78,79. There has been little research as to the efficacy of drugs administered via the tracheal route in children. The optimal dose of drug, its volume and its concentration has yet to be formally established^80-83. Tracheal administration, despite its apparent simplicity, does have some disadvantages especially in the post resuscitation period. Hypertension and tachycardia, neither of which are optimal in the post arrest myocardium, have been reported and attributed to the depot storage effect of adrenaline that occurs in the lungs^84-88. Severe hypertension may also be an underlying cause for a poor cerebral outcome⁸⁹.

Although direct intracardiac injection is still occasionally practiced, less than 70% of injections enter the heart and serious cardiac damage may occur. It is not recommended. 

(Continued ...)

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