The recommendations for advanced CPR given here are based on publications of the Australian Resuscitation Council,¹ the European Resuscitation Council,² the American Heart Association³ and the International Liaison Committee on Resuscitation (ILCOR).⁴ They are intended for use by medical and nursing personnel in hospital and by ambulance personnel in the field.

To add ability to knowledge, it is advisable to undertake a specialised paediatric cardiopulmonary resuscitation course such as the Advanced Paediatric Life Support (APLS) or Paediatric Advanced Life Support (PALS) courses.

Distinctions within the term ‘paediatric’ are based on combinations of physiology, physical size and age. Some aspects of CPR are different for ‘the newly born’, infant, small (younger) child and large (older) child. In this section, ‘infant’ refers to an infant outside the delivery room (the ‘newly-born’ infant) and includes the period starting from a few hours after birth up to the age of 12 months. Other terms such as newborn or neonate do not enable that distinction. ‘Small/young child’ refers to a child of pre-school and early primary school from the age of 1 to 8 years. ‘Large/older child’ refers to a child of late primary school from the age of 9 up to 14 years. Although ventricular fibrillation occurs in children, they are at less risk than adults. One guideline regards children of 8 years and over as adults specifically for use of semi-automated external defibrillators (sAED) out-of-hospital.

Diagnosing cardiac arrest

Healthcare personnel (doctors and nurses) have difficulty diagnosing cardiac arrest in infants and children if they rely on pulse palpation alone. Their accuracy is approximately 80% with a sensitivity of 0.85 and specificity of 0.65,⁵ which means that in 15% of circumstances they would not give CPR when needed and would give it in 35% when not needed. While application of CPR is not harmful when there is a circulation, the withholding of CPR when there is none dooms the patient to die. The time taken to diagnose cardiac arrest is longer than hitherto realised⁶ – as a group, healthcare personnel take an average of 15 seconds to exclude cardiac arrest by finding a pulse but 30 seconds to diagnose real cardiac arrest by the absence of a pulse. However, the accuracy and expediency of diagnosis are related to experience and training. Only experienced personnel who palpate pulses on a daily basis are able to detect a real pulse within 10 seconds but they, like inexperienced personnel, are unable to quickly diagnose cardiac arrest by the lack of a pulse and need on average about 25 seconds to confirm it. Clinical guidelines advise to spend no more than 10 seconds on pulse palpation and to combine whatever information is gained with observable signs of circulation such as responsiveness, movement and presence or absence of normal respiration. In short, if the patient is unresponsive and not breathing normally there is no point wasting time on pulse palpation (it is inaccurate and time consuming). Instead give CPR immediately.

Epidemiology

The causes of cardiopulmonary arrest in infants and children are many and include any cause of hypoxaemia or hypotension, or both. Common causes are trauma (motor vehicle accidents, near drowning, falls, burns, gunshots), drug overdose and poisoning, respiratory illness (asthma, upper airway obstruction, parenchymal diseases), post-operative (especially cardiac), septicaemia and sudden infant death syndrome.

Oxygen, ventilation and advanced airway support

Oxygen

Oxygen should be administered whenever hypoxaemia occurs but evidence from animal and newborn infant studies suggests that as soon as oxygenation is achieved the inspired oxygen (FiO₂) should be regulated to yield arterial oxygen partial pressure in the normal range in order to limit oxygen-mediated cell damage. The only exception to administration of oxygen is when it may cause pulmonary vasodilatation and thereby shunt blood to the lungs away from the systemic circulation, as may occur in an infant with a single ventricle which pumps blood to both circulations. Chronic hypoventilation is not an indication to withhold oxygen therapy during CPR for infants and children.

Numerous devices may be used to supply supplemental oxygen. The choice is dictated by the required inspired oxygen concentration (FiO₂), cost, avoidance of CO₂ rebreathing, imposed airway resistance and tolerance by the patient.

Oxygen catheters

These are easy to use, cheap, do not cause rebreathing and are well tolerated (permitting eating and drinking) but are limited to supply of up to 40% inspired O₂ because of restriction to gas flow (maximum 4 L min^–1) and limitation of gas reservoir (the nasopharynx). Sizes 6, 8 and 10 FG should be available and placed in the same nostril as the nasogastric tube, to limit airway resistance. Size 6 FG is suitable for infants, 8 FG for small children and 10 FG for older children. Excessive flow may desiccate mucosal membranes and cause gastric distension, which can embarrass respiration.

Oxygen is delivered by nasal cannulae (bi-pronged, ‘nasal prongs’), which sit at the entrance to the nose or a few centimetres inside, need no humidification and do not cause gastric distension. They may become obstructed by mucus and may obstruct the nose. Flow rates for infants should be regulated by a low-flow meter, graduated 0–2.5 L min^–1. Rates of 0.24–4 L min^–1 provide 40–70% O₂ to infants 1–10 kg body weight (BW). Improved oxygenation may be caused in part by positive end expiratory pressure (PEEP).

An oxygen catheter placed in the nasopharynx a distance equivalent to that from ala nasi to tragus provides a small amount of PEEP, and indeed may be used for that purpose. Oxygen concentrations of 30%, 40% and 50% approximately are provided by flows of 45, 80 and 150 mL kg^–1 min^–1 respectively. This technique to provide ‘PEEP’ may be useful to temporarily abort central apnoea in the young infant with RSV, whilst other treatment such as caffeine infusion is established.

Oxygen prongs

Non-humidified oxygen is subject to the same flow restriction as nasal catheters (up to 4 L min^–1). The use of ‘high flow’ (≥8 L min^–1) humidified oxygen as a means to provide CPAP and thereby prevent apnoea, although an attractive technique, has not yet proven to be advantageous in infants outside the premature age group.

Oxygen masks

Semi-rigid face masks of the Hudson type can supply approximately 35–70% O₂ at flow rates of 4–15 L min^–1. However, they may not be well tolerated by the infant or small child, and the distress they cause may consume energy in the tiring child. They may cause rebreathing or fail to deliver the desired FiO₂, especially when peak inspiratory flow rate (PIFR) is high, thus entraining excessive room air. Masks that incorporate a reservoir bag or a Venturi may deliver up to 80% O₂ but, likewise, may cause rebreathing if the flow rate does not match PIFR during respiratory distress.

Head boxes and incubators

A clear Perspex head box is the best way of administering a high concentration of oxygen to the unintubated infant. It allows a non-distressing delivery of oxygen and allows clear observation of the child. Precise oxygen therapy is possible but may be expensive and rebreathing, heat loss and desiccation are potential problems. To avoid rebreathing, a large flow rate (10–12 L min⁻¹) of fresh gas with predetermined oxygen content should be introduced. The practice of introducing a low-flow rate of 100% oxygen into a head box (to gain a lesser concentration) may cause hypercarbia. If 100% oxygen is the only compressed gas available, lesser concentrations of oxygen may be attained without rebreathing by using a flow of 100% oxygen and a Venturi device. The relatively large capacity of an incubator precludes the attainment of a high concentration of oxygen, but limited oxygen therapy, up to a maximum of 60%, can be achieved at the cost of very high flow rates. The concentration of oxygen in the head box can be monitored with an analyser and help monitor the progress of the lung disease and oxygen requirements.

Ventilation

Bag–mask ventilation

As soon as practicable, mechanical ventilation with added oxygen should be commenced with either a bag–mask (bag–valve–mask) or via endotracheal intubation. Although intubation is preferred (see below), valuable time should not be wasted in numerous unsuccessful attempts. Initial effective bag–mask ventilation is a necessary prerequisite for successful paediatric CPR but it is a relatively difficult technique to learn and to perform well in emergency circumstances. Practice on mannequins or in an anaesthetic setting is invaluable in learning to perform this well for the infrequent paediatric resuscitation.

Bags of appropriate sizes should be available for infants, small children and large children. A bag of approximately 500 mL volume should be available for newborn infants and infants.

Insertion of an oropharyngeal (Guedel) airway may be necessary to facilitate bag–mask ventilation. Two types of resuscitation devices are available: flow-inflating and self-inflating bags. They can be attached to a mask, laryngeal mask airway (LMA), endotracheal tube or tracheostomy.

Flow-inflating bags

These are designed to give either positive pressure ventilation or to allow a patient to breathe spontaneously. They are exemplified by Jackson-Rees modified Ayre’s T-piece. Gas flow must exceed 220 mL kg^–1 min^–1 for children and 3 L min^–1 for infants, to prevent rebreathing during manual ventilation. It is possible to control precisely the concentration of inspired oxygen, which is an advantage, especially for the premature neonate at risk of oxygen-induced retrolental fibroplasia. However, considerable experience is necessary to provide adequate ventilation without barotrauma in the intubated infant. A pressure gauge and a relief valve should be incorporated in the circuit to help prevent barotrauma.

Self-inflating bags

These bags are designed only to give positive pressure ventilation. Rebreathing is prevented by one-way duck-bill valves, spring disk/ball valves or diaphragm/leaf valves. The Laerdal bag series (infant, child, adult) typifies these devices. A pressure-relief valve (infant and child size) opens at 35 cm H₂O (3.5 kPa). A pressure monitor can be incorporated in the circuit. Supplemental oxygen is added to the resuscitation bag, with or without attachment of a reservoir bag, whose movement may serve as a visual monitor of tidal volume during spontaneous ventilation when intubated. However, the valve may offer resistance for spontaneous ventilation and this is important to consider in the spontaneously breathing child just prior to the effect of relaxants of rapid sequence induction prior to intubation.

These bags should not be used to provide supplemental oxygen to a spontaneously breathing patient with a mask placed near or loosely over the face. With Laerdal and Partner bags, negligible amounts of oxygen (0.1–0.3 L min^–1) issue from the patient valve when 5–15 L min^–1 of oxygen is introduced into bags unconnected to patients.⁷ The patient valve is unlikely to open unless the mask is sealed well on the face. Although not recommended, if they are used in this way, it is vital to ensure that the patient valve opens or the reservoir bags deflates in unison with the chest movement.

The delivered oxygen concentration is dependent on the flow rate of oxygen, use of the reservoir bag, and the state of the pressure relief valve (whether open or closed). In the Laerdal series, with use of the reservoir bag and oxygen flow greater than the minute ventilation, 100% oxygen is delivered. Without the reservoir bag the delivered gas is only 50% oxygen, despite oxygen flow rate at twice minute ventilation. At an oxygen flow rate of 10 L min^–1 to the infant resuscitator bag, the delivered gas is 85–100% oxygen without the use of the reservoir bag.

Rates and ratios of external cardiac compression and ventilation in ALS

The techniques of external cardiac compression and expired air resuscitation (mouth-to-mouth) or rescue breathing are described in Section 2.2. The recommended ratio of external cardiac compression to ventilation in basic life support by a single rescuer is 30:2^1–4 which if able to be repeated 5 times in 2 minutes, with pauses for ventilations, would yield approximately 75 compressions and 5 breaths per minute.

In advanced life support the recommended ratio of compressions to ventilation by 2 rescuers is 15:2^1–4 which, if repeated 5 times in 1 minute, with pauses for ventilation by bag–mask, would yield approximately 75 compressions and 10 ventilations per minute. When the patient is intubated, it is undesirable and not necessary to pause cardiac compressions to give ventilations because they can be delivered effectively during cardiac compressions and cardiac compressions can be given continuously without interruption. Every time cardiac compression is interrupted, cardiac stroke volume obviously falls to zero and then several successive compressions are required to re-establish the stroke volume achieved before interruption. Necessary interruptions to cardiac compressions should be minimized by co-ordinated planning, to for example, analyse the cardiac rhythm or to give DC shock. Effort must be directed towards minimizing ?hands-off time? during requirement for cardiac compression.

Advanced airway support

Tracheal intubation

The trachea should be intubated as soon as practicable but it can be deferred if successful bag–mask ventilation can be given and should not be undertaken by inexperienced personnel out-of-hospital ⁸ because of complications and poorer outcomes compared with use of bag–mask ventilation. Nonetheless, intubation has numerous advantages, which include establishment and maintenance of the airway, facilitation of mechanical ventilation, titration of oxygen therapy, minimisation of the risk of pulmonary aspiration, enablement of tracheal suction, provision of a route for the administration of selected drugs and preferred for transport and long-term ventilation. Regurgitation of gastric contents is common during cardiac arrest.

Hypoxaemia should be avoided during attempts at intubation – which should be limited to 30 seconds. If difficulty is experienced, oxygenation should be re-established with bag–mask ventilation before a reattempt at intubation. Initial intubation should be via the oral route, not via the nasal route. The oral route is invariably quicker, is less likely to cause trauma and haemorrhage and the endotracheal tube is more easily exchanged if the first choice is inappropriate. On the other hand, a tube placed nasally can be better affixed to the face and so is less likely to enter a bronchus or be inadvertently dislodged during transport or other procedures. A nasal tube is preferred subsequently for long-term management. A nasogastric tube should be inserted after intubation to relieve possible gaseous distension of the stomach sustained during bag–mask ventilation.

Correct placement of the endotracheal tube in the trachea must be confirmed immediately. In the hurried conditions of emergency intubation at cardiopulmonary arrest, it is not difficult to mistakenly intubate the oesophagus or to intubate a bronchus. There is no substitute for visualising the passage of the tip of the endotracheal tube through the vocal cords, confirmation of bilateral pulmonary air entry by auscultation in the axillae, continuous observation of rise and fall of the chest on ventilation and maintenance of a pink complexion. In addition, it is recommended that correct placement of the endotracheal tube be confirmed by capnography or CO₂ detection, with the realisation that CO₂ excretion can only occur with effective pulmonary blood flow. This implies that CO₂ detection cannot be expected unless spontaneous cardiac output returns or external cardiac compression is effective. Absent CO₂ detection mandates re-intubation or at least inspection that the tube is indeed passing through the vocal cords. High CO₂ indicates poor ventilation. Oxygenation should be confirmed with use of a pulse oximeter or measurement of arterial gas tension.

Endotracheal tube size (Table 2.3.1)

Uncuffed sizes are 2.5 mm for a premature newborn <1 kg, 3.0 mm for infants 1–3.5 kg, 3.5 mm for infants >3.5 kg and up to age of six months, size 4 mm for infants seven months to one year (Table 2.3.1). The approximate size may be chosen for children over one year by the formula: size (mm) = age (years)/4 + 4. Tubes one size larger and smaller should be readily available. The correct size should allow a small leak on application of moderate pressure but also enable adequate pulmonary inflation. If the lungs are non-compliant, however, it may be necessary to insert a tube without a leak or insert a cuffed tube. Appropriate- sized cuffed tubes may be estimated by the formula: size (mm) = age (years)/4 + 3.5.

Depth of tube insertion (Table 2.3.1)

The tube is inserted to a specific numerical depth to avoid accidental extubation or endobronchial intubation. Assessment of the depth of insertion during laryngoscopy by noting passage through the vocal cords is not completely reliable since alteration of head position affects depth of tube insertion. The tube depth increases with neck flexion (goes in) and decreases (comes out) during extension. Since intubation is usually performed with the head extended, the tube depth increases when the laryngoscope is removed and the head assumes a position of neutrality or flexion. In a neutral head position, an appropriate depth of insertion measured from the centre of the lips for an oral tube is 9.5 cm for a term newborn, 11.5 cm for a 6-month-old infant, 12 cm for a 1-year-old. After 1 year the depth is given by the formula: depth (cm) = age (years)/2 + 12. An alternative formula for oral tube depth of insertion is: depth (cm) = size (mm) × 3 when an appropriate tube size for age is used. The appropriate depth of insertion for a nasal tube in this age group is: depth (cm) = age (years)/2 + 15. On a chest X-ray taken with the head in neutral position, the tip of the tube should be at the interclavicular line.

Laryngeal mask airway (LMA)

These have been used for resuscitation by medical, nursing and ambulance personnel trained in their selection and insertion. They may be used to maintain an airway and are a suitable alternative to the use of airway opening manoeuvres and use of oropharyngeal and nasopharyngeal airways. They are useful to establish an airway in the setting of airway obstruction or failed intubation.⁹ An intubating LMA serves as a conduit for intubation.

However, the role of LMA in provision of mechanical ventilation remains uncertain. Like bag–mask ventilation, they do not protect the airway from aspiration, which occurs commonly during cardiopulmonary resuscitation. They are a suitable alternative to a face mask as a means to give ventilation before endotracheal intubation and when intubation is difficult. This is a better technique when the operator is unskilled in the use of LMA and intubation. Although insertion of an LMA is easier to learn than endotracheal intubation, training should not replace mastery of bag–mask ventilation. They should not be used in semi-conscious patients or when the gag reflex is present and are not suitable for long-term use or use during transport when endotracheal intubation is far preferable. They are subject to dislodgment during movement and transport. Appropriate sizes according to body weight are given in Table 2.3.2.

Sizes are available to suit body weight (kg) of newborns, infants and children Size Weight (kg) 1 <5

5–10 2 10–20

20–30 3 30–50 4 50–70 5 70–100 6 >100

Management of the difficult airway

Unfortunately, unanticipated difficulties with the airway and intubation or failures to follow a prepared plan to cope with difficult and failed intubation continue to cause deaths, irrespective of the degree of skill of the operator.

The airway can be difficult to maintain because of unusual anatomy, injury or illnesses or because of loss of natural maintenance after administration of drugs, which depress consciousness, muscle tone or activity. ‘Airway difficulties’ refer to maintenance of the airway, bag–mask ventilation and endotracheal intubation. Each situation may rapidly lead to hypoxaemic brain damage and death.

Resuscitators must be well-skilled in the management of the airway and provision of bag–mask ventilation. It is vital to possess good basic resuscitation techniques (see Chapter 2.2 on basic life support), to be familiar with equipment, to have skilled assistance and to have appropriate equipment ready-to-hand. They must also be familiar with manoeuvres to overcome difficulties with airway maintenance, bag–mask ventilation and intubation. Resuscitators must also have a pre-conceived plan to cope with difficult and failed (impossible) intubation, especially when bag–mask ventilation fails (Fig. 2.3.1).

Fig. 2.3.1 Management of difficult and impossible intubation.

An obstructed airway may be relieved by simple repositioning of the patient’s head and neck, pharyngeal suction, use of an alternative airway-opening manoeuvre, insertion of an oropharyngeal or nasopharyngeal airway and help by an assistant. Persistent obstruction requires urgent endotracheal intubation.

Difficult intubation

With good technique, normally, intubation can be achieved via direct laryngoscopy with a direct line of sight to the glottis. Sometimes ‘difficult intubation’ is a consequence of anatomical abnormality, trauma or infection but sometimes it is simply the result of operator unpreparedness or incorrect choice or use of equipment or lack of knowledge of simple techniques to overcome difficulties.

Anatomical difficulties

Certain conditions imply that intubation will not be easy but it is prudent to inspect the facial and pharyngeal anatomy of every patient before giving sedation or anaesthesia. Common anatomical variants in many conditions, which will disallow a direct line of sight to the larynx are an ‘anterior’ larynx, prominent upper incisors, a large tongue or a small hypoplastic mandible. Thus Treacher Collins syndrome and Pierre–Robin syndrome (sequence) with mandibular hypoplasia and Beckwith–Wiedemann syndrome with macroglossia are typical conditions in which difficult intubation should be anticipated.

Difficulty with intubation may be unanticipated, but may be predicted with three simple observations. One of these is the relative tongue/pharyngeal size (‘Mallampati’ test): if the faucial pillars, soft palate and uvula are obscured by the extended tongue on maximum mouth opening, intubation will be difficult. Another predictor is the extent of possible atlanto-occipital extension. If this is less than 35° intubation will be difficult. This corresponds to the angle between the occlusal surface of the upper teeth and horizontal plane when the head is maximally extended. The third predictor is the amount of mandibular space into which the tongue must be compressed to allow a line of sight to the glottis. This space can be judged by the distance from the thyroid cartilage or hyoid bone to the point of the mandible (thyromental, submental distances) or by the horizontal length of the mandible. In adult-sized patients a thyromental distance of greater than 6 cm and a mandibular length of greater than 9 cm predict easy intubation. Unfortunately, no such distances are known for children and infants.

Thus, the evaluation of intubation difficulty should include pharyngeal examination with extended tongue, inspection of mandibular size or submental space and examination of atlanto-occipital angle. These special measures should be in addition to routine history of airway management, as would have occurred in previous anaesthesia, inspection of nostrils and history and examination of cardiorespiratory function.

Equipment and technical difficulties

Although Magill’s forceps are very useful for directing the tube into the larynx, the use of simple ‘tricks’ may facilitate intubation. For example, it is important that the patient’s head and neck be correctly positioned in the so-called ‘sniffing’ position (neck flexed, head slightly extended) to offer the best line of sight to the larynx. In the neonate and infant, however, the head and neck should remain in the neutral position. The blade of a regular laryngoscope is designed to be introduced into the right side of the mouth (not the left) so that when the blade is subsequently centred the tongue is displaced to the left and an unimpeded view of the larynx and sufficient working space is afforded. The tip of a curved-bladed laryngoscope (Mackintosh type) is placed in the vallecula (space between base of tongue and epiglottis) whereas the tip of a straight-bladed laryngoscope is placed behind the epiglottis. The laryngoscope handle is then elevated upward and away from the operator to lift the tongue out of the line of sight to the glottis. The handle should not be elevated directly upwards or elevated back towards the operator – such actions may not displace the tongue sufficiently and fail to bring the glottis into view, and moreover may damage the upper teeth. The upper teeth should not be used as a leverage point.

The bevel of an endotracheal tube is angled so that it easily enters the trachea when introduced from the right side of the mouth. One should insert the tube keeping it oriented in a horizontal plane, rather than vertical, so that the presence of the tube does not impede the intubator’s view of the larynx. This may be facilitated by an assistant pulling down on the corner of the mouth. When introduced from the left side, the tip of the bevel may stick at the laryngeal inlet – but this can be easily remedied by rotating the tube anticlockwise, thus changing the angle of approach and directing the tip more toward the centre of the laryngeal inlet rather than to its right side. If the tip of the upward curving tube sticks in the anterior larynx, flexion of the neck may direct the tube posteriorly and encourage it to enter the larynx. If the larynx is anterior and difficult or impossible to see, use of an introducing stylet to create a more acute curve at the tube tip may achieve intubation and/or application of posterior cricoid pressure may bring the anterior larynx into view. A tube may be placed ‘blindly’ into the trachea with or without the use of a stylet or bougie over which a tube can be railroaded. Skilled anticipatory assistance and good suction by a dedicated airway nurse who anticipates the needs of the intubator are essential. Occasionally, a gentle finger of an assistant retracting the lip of the child may enlarge the oral opening to afford improved vision and field to place the endotracheal tube down the right side of the mouth.

Many other items of equipment are available to assist when intubation proves to be difficult. These include laryngoscopes that have a tip independent of the shaft of the blade, which is used to elevate the epiglottis (e.g. McCoy laryngoscope, Penlon), or which incorporate a prism to give a view of an anterior larynx (e.g. Belscope), illuminating stylets and intubating bronchoscopes. Illuminating stylets are malleable and give a ‘Jack-o’-lantern’ effect when correctly located in the trachea. All items of equipment are useless unless they are ready-to-hand and are familiar to the operator.

A two-person intubating technique may achieve intubation in difficult circumstances. In this, one person holds the laryngoscope with their left hand and applies cricoid pressure with their right to bring the larynx into view, while a second person applies suction, holds the lower lip out of the way and attempts to pass the endotracheal tube.

Another technique is retrograde intubation (translaryngeal-guided) in which a guide wire is threaded through a needle or intravenous catheter inserted cephalad through the cricothyroid membrane. The end of the wire is retrieved from the oral or nasal cavity, pulled taut and used as a ‘tightrope’ over which an endotracheal tube is railroaded into the trachea. Alternatively, a string can be tied to the end of the wire which is then drawn from the tracheal puncture. The proximal end of the string can be tied to the Murphy eye of a tube, which is then pulled from below into the trachea. A nasal endotracheal tube can be placed by joining a wire (or string) inserted into the oral cavity via the nasal route and joining it to the wire or string entering the oral cavity via the trachea. Retrograde intubation is a useful technique in cases such as facial trauma, trismus and upper airway masses.

Failed intubation

If endotracheal intubation is impossible when needed, the resuscitator must be able to oxygenate the patient while preparations are made for tracheostomy or until intubation can be somehow achieved.

Attempts at intubation should not be prolonged, so that hypoxaemia is not caused. Oxygenation should be restored with intermittent bag–mask ventilation. Likewise, intubation attempts should not be overly repetitive because the larynx will be traumatised and this may render bag–mask ventilation, previously possible, now impossible for the more-skilled operator when they arrive. In situations where intubation is not absolutely needed (i.e. not life-saving) it is prudent to revert to bag–mask ventilation (if that is possible) rather than persist in intubation attempts, which could ultimately damage the larynx and render bag–mask ventilation impossible. If ventilation is not possible by mask, sometimes application of CPAP with 100% oxygen via an Ayre’s T-piece will suffice to maintain oxygenation. Prolonged CPAP cannot be effectively applied with a mask using a self-inflating resuscitator bag.

If the airway is totally obstructed and neither bag–mask ventilation nor intubation can be performed, the situation is more desperate. Adequate oxygenation (but not normal ventilation) can be obtained by inserting a trans-tracheal catheter (Mallinckrodt Medical Pty Ltd) otherwise intended for jet-ventilation, or a 14-gauge intravenous cannula percutaneously into the trachea caudad via the cricothyroid membrane (which lies immediately inferior to the thyroid cartilage). To do this, the patient should be lying straight, with the cannula in the midline and angled towards the feet. After removing the needle, the trans-tracheal catheter can be connected directly via its standard 22 mm connector to a bagging circuit. An intravenous cannula can be connected by various ways to a source of oxygen. One of these is direct connection to a resuscitator or a bagging circuit using a connector from a 3.0 mm endotracheal tube. Alternatively, the cannula can be connected to continuous oxygen supply via a three-way intravenous tap (to allow expiration) and a length of plastic tubing. Another option is use of plastic tubing alone that has a side hole cut or a Y-piece inserted, which is intermittently occluded to cause inspiration (1 second) and unoccluded (3 seconds) to allow expiration. With all these techniques care should be taken to allow expiration to avoid barotrauma. Expiration may need to be assisted by lateral chest compression as the arrested patient may not spontaneously expire much air. Ventilation is very difficult but oxygen can be supplied by sustained pressure.

A semipermanent solution for a totally obstructed airway is cricothyro(s)tomy. To do this the larynx is stabilised throughout the procedure with fingers of one hand while skin over the thyroid–cricoid membrane (between the thyroid and cricoid cartilages) is incised with a scalpel held in the other. Then, bluntly dissect into the trachea with forceps in the midline or incise vertically with the scalpel. Insert a small tracheostomy, preferably bevelled, or a small endotracheal tube. Alternatively, perform percutaneous mini-tracheostomy. A formal tracheostomy should be organised while these measures are undertaken. An important part of a contingency plan to cope with unexpected difficulties is to have easily contactable more experienced operators.

Monitoring

Vital signs

Routine monitoring of heart rate, respiratory rate and blood pressure are essential for infants and children with critical illness. It is prudent to have ready access or to have displayed the normal age-related values visually available in the paediatric resuscitation area of the ED as an aide-memoire.

Oximetry

Transcutaneous oximetry (SpO₂) is essential monitoring in critically ill patients. It equates well to arterial haemoglobin oxygen saturation (SaO₂) but not when the SaO₂ is below 70%. Note that an SpO₂ of 90%, although only 10% below normal, represents a partial pressure of oxygen in arterial blood (PaO₂) of 60 mmHg, which is 40 mmHg below normal.

Expired CO₂ detection

Confirmation of endotracheal intubation

End-tidal CO₂ (P_etCO₂) is recommended after every tracheal intubation and during mechanical ventilation to guard against inadvertent oesophageal intubation and inadvertent extubation, particularly when the intubated patient undergoes transport to, within or between hospitals. Small movements of head and neck, as may occur for example on transfer from one trolley to another or to a bed, may dislodge an endotracheal tube. No CO₂ is excreted unless there is pulmonary blood flow so undetectable CO₂ after intubation basically represents non-tracheal intubation or absence of circulation, or both.

Regulation of cardiac compression and ventilation

To achieve optimum CO₂ excretion, cardiac output and pulmonary ventilation must be matched. A common error in advanced CPR is giving ventilation in excess of the limited cardiac output achievable by external cardiac compression, which is likely to be no more than a third of normal cardiac output. Ventilation can be safely reduced proportionately. Moreover, excessive ventilation not only interferes with performance of external cardiac compression but also increases intrathoracic pressure inhibiting venous return and cardiac output and may cause hypocarbia which causes cerebral ischaemia by vasoconstriction. On the other hand, inadequate ventilation contributes to hypercarbia, acidosis and cerebral vasodilation. After tracheal intubation, end-tidal CO₂ should be monitored by capnography. If end-tidal CO₂ is low, excessive ventilation and inadequate external cardiac compression (rate, depth of compression) should be excluded as causes.

Electrocardiograph (ECG)

The ECG should be displayed with either leads, pads or paddles. Drug therapy or immediate direct current shock is administered according to the existing rhythm. Electrolyte status, especially that of potassium and calcium, may be indicated by ECG patterns.

Vascular access

Peripheral venous cannulation

Access to the circulation via a peripheral vein should be attempted immediately on CPA. Any site is acceptable. Visible or palpable peripheral veins are to be found on the dorsum of the hand, wrist, forearm, cubital fossa, chest wall, foot and ankle. In infants, scalp veins are accessible and the umbilical vein can be used up to about a week after birth. The external jugulars are usually distended during CPR and easy to cannulate but this may be impeded by performance of intubation.

Intraosseous access

If peripheral intravenous access cannot be rapidly achieved, say within 60 seconds, intraosseous access should be obtained. This route has been used for patients of all ages. It provides rapid, safe and reliable access to the circulation and serves as an adequate route for any parenteral drug and fluid administration. Syringing via a three-way tap is usually needed. The use of purpose-made intraosseous bone injection needles (e.g. Cook Aus Pty Ltd, 16g, 3 cm POWCH design) is preferable, although a short lumbar puncture type of needle with an inner trocar may suffice.

The handle of the device needle is held in the palm of the hand while the fingers grip the shaft about a centimetre from the tip. It is inserted perpendicular to the bone surface and a rotary action is used to traverse the cortex. Sudden loss of resistance signifies entry to bone marrow and the needle should stand unsupported. Correct positioning of the needle is confirmed by aspiration of bone marrow (which may be used for biochemical and haematological purposes) but that is not always possible. A bone marrow injection gun (Wais Med Ltd) which fires a needle a pre-set distance according to size of the patient or a bone marrow drill (EZ-IO, Vidacare) enables easy and rapid intraosseous infusion/injection for infants, children and adults. The latter device is preferred. Having an intraosseous drill available in the ED can provide extremely rapid access to the circulation in a child arriving in CPA.

Although many sites have been used for bone marrow injection, the easiest to identify is the anteromedial surface of the upper or lower tibia. The site of the latter is a few centimetres below the anterior tuberosity and the former a few centimetres above the medial malleolus. Care should be exercised to avoid complications, particularly cutaneous extravasation, compartment syndrome of the leg, and osteomyelitis. Contraindications include local trauma and infection.

Central venous cannulation

Cannulation of femoral, subclavian, or internal jugulars or external jugular veins are options. However, central cannulation is difficult in the setting of cardiorespiratory arrest and fraught with potential serious complications such as pneumothorax unless the operator is well practised. This technique is not recommended in the setting of an arrested child as the intraosseous route is more timely.

Endotracheal route

Drugs are absorbed into the circulation from the airways. Lipid-soluble drugs (adrenaline [epinephrine], atropine, lidocaine and naloxone) may be administered via the endotracheal tube if either intravenous or intraosseous access is non-existent. Although the optimal doses of these drugs by this route are not known, work in animal models suggests doses should be ten-times the intravenous doses. The drugs should be diluted in normal saline up to 2 mL for infants, 5 mL for small children and 10 mL for large children. It is acceptable and simplest to squirt the drugs from the syringe directly into the endotracheal tube and disperse them throughout the respiratory tree with bagging. Neither sodium bicarbonate nor calcium salts should be administered via the tracheal route because they injure the airways.

Other techniques

Surgical cutdown onto a long saphenous, saphenofemoral junction or basilic is a valuable skill sometimes required in traumatic exsanguination. Very occasionally, injection into the superior sagittal sinus of an infant ¹ may be the only vascular access available. Any pre-existing functioning line can be used provided it does not contain any drug or electrolyte, which may have caused the CPA.

Fluid therapy

Circulatory hypovolaemia is expected in trauma, sepsis, dehydration and anaphylactic states. Restoration of intravascular volume should be with isotonic crystalloid solutions (0.9% normal saline or Hartmann’s solution) or a colloidal solution such as 4% albumin. There is insufficient evidence to choose between these. Aliquots of 20 mL kg^–1 intravenously or intraosseously are reasonable volumes to administer in shock states with titration against indices of vascular volume. It is reasonable to administer blood in traumatic haemorrhage if 40–60 mL kg^–1 has not restored normal blood volume (70–80 mL kg^–1). The role of hypertonic solutions is not yet defined for children with hypovolaemic shock, but these solutions are in regular use for patients with severe head injury. Dextrose-containing solutions are inadvisable in acute resuscitation unless hypoglycaemia is proven since they may cause osmotic diuresis. Drugs should be flushed into the circulation with boluses of isotonic crystalloid solution.

Resuscitation drugs

Direct current shock

Unsynchronised DC shock is required as first treatment for VF and pulseless VT. If effective for VF it is called defibrillation. Synchronised DC shock may also be required for pulsatile VT and haemodynamically unstable supraventricular tachycardia (SVT).

Operators of defibrillators should be constantly alert to the possibility of inadvertent electrocution and cardiac arrest of themselves and others by misuse. Pads have advantages over paddles; they minimise risk of inadvertent shock to the operator and importantly, allow application of shock with minimal disruption to external cardiac compression. Paddles should be charged after placement on the patient, not before. Charged paddles should never be carried in one hand and never discharged in the air. If after charging, discharge is not needed, the paddles should be replaced in their storage holders before discharge. It is important that no-one is in contact with the patient or the bed or trolley at the time of discharge.

Defibrillators should have paediatric paddles of cross sectional area 12–20 cm² for use in children <10 kg. For others, adult-sized paddles (50–80 cm²) are satisfactory provided the paddles do not contact each other. Selectable energy levels should enable delivery of doses 0.5–5 J kg^–1. Doses should be rounded up to the closest weight-based dose. For use in the anterolateral positions, one pad/paddle is placed over the mid-axilla opposite the xyphoid or nipple, the other to the right of the upper sternum below the clavicle. Conductive gel (confined to the area beneath the paddles) or gel pads and firm pressure are needed to deliver optimum energy to the heart without causing skin burns. An anteroposterior position of pads is the preferred positioning (one over cardiac apex or anterior chest, one over left scapula). Dextrocardia may be present with congenital heart disease and the position of the pads/paddles should be altered accordingly.

In the absence of a manual dose regulated defibrillator, semi-automated automatic external defibrillation (sAED) may be used for children but preferably should have an ‘attenuated’ adult dose. A dose of 50 J is appropriate for most infants and children. However, if a machine with such attenuated dosing is not available, the use of an adult sAED delivering 150–200 J is acceptable for infants and children^1–4 rather than leave untreated a shockable rhythm. The use of an sAED with adult doses of DC shock for children in hospital should not be considered unless a manual dose regulated defibrillator is not available or cannot be used or a body weight specific DC shock cannot be delivered within 3 minutes when indicated.

Management of pulseless arrhythmias (Fig. 2.3.2)

The following discussion assumes that mechanical ventilation with oxygen and external cardiac compression (ECC) have been commenced and continued if an adequate pulse rate is not detectable. The treatment of pulseless arrhythmias (ventricular fibrillation, ventricular tachycardia, asystole, electromechanical dissociation and pulseless electrical activity) are summarised in Fig. 2.3.2

Fig. 2.3.2 Advanced cardiopulmonary resuscitation for infants and children. Adapted from resuscitation guidelines of the International Liaison Committee on Resuscitation, Australian Resuscitation Council, European Resuscitation Council and of the American Heart Association, December 2010. Australian Resuscitation Council.

Key: CPR, cardiopulmonary resuscitation; ECG, electrocardiograph; IO, intraosseous; IV, intravenous; J, joules; kg, kilogram; mg, milligram; mcg, microgram.

Specific causes of arrhythmias should be treated. For example, calcium channel blockade toxicity is treated with calcium IV or IO (chloride 10% 0.2 mL kg^–1, gluconate 10% 0.7 mL kg^–1); hyperkalaemia treated with calcium salt, sodium bicarbonate, hyperventilation, insulin and dextrose. All drugs should be flushed into the circulation with a small bolus of isotonic fluid. To prevent inactivation, drugs should not be mixed in the syringe or in infusion lines.

Asystole

Asystole should be treated with adrenaline (epinephrine) 10 mcg kg^–1 IV or IO. If these routes are not available, adrenaline 100 μg kg^–1 should be administered via endotracheal tube (ETT). Unresponsive asystole should be treated with similar doses (10 μg kg^–1 IV, IO; 100 μg kg^–1 ETT) every 3–5 minutes. Higher doses, up to 200 μg kg^–1 IV or IO may be used, but have not altered outcome and predispose to complications (post-arrest myocardial dysfunction, hypertension, tachycardia). In newborn infants, the initial bolus dose is 10–30 mcg kg^–1 (0.1–0.3 mL kg^–1 of 1,10:000 solution). Persistent or recurrent bradyarrhythmia or asystole may require an infusion of adrenaline at 0.05–3 mcg kg^–1 min^–1. Doses of <0.3 mcg kg^–1 min^–1 are predominantly β-adrenergic, doses >0.3 mcg kg^–1 min^–1 are predominantly α-adrenergic. Infuse into a secure large vein. If sinus rhythm cannot be restored, sodium bicarbonate 1 mmol kg^–1 IV or IO may be helpful but do not allow mixing with adrenaline since catecholamines are inactivated in alkaline solution. Pacing is not helpful for asystole.

Pulseless electrical activity (PEA) and electromechanical dissociation (EMD)

A normal ECG complex without pulses is called electromechanical dissociation (EMD). If untreated, the ECG deteriorates to an abnormal but still recognisable state when it is called pulseless electrical activity (PEA). Both conditions should be treated as for asystole and their causes ascertained and treated.

Ventricular fibrillation and pulseless ventricular tachycardia

In approximately 10% of paediatric cardiac arrests the initial identified rhythm is VF or pulseless VT. As soon as recognised, VF or pulseless VT should be treated with unsynchronized DC shock. If onset is witnessed in a monitored environment, a precordial thump may be given but its efficacy has not been proven.

Either monophasic or biphasic waveforms may be used. The optimum dose of external DC shock in terms of achieving first shock success with minimal damage to the myocardium is unknown. Some guidelines recommend a dose of 2–4 J kg⁻¹.^3,⁴ The dose of 2 J kg^–1 is considered too little by other guidelines^1,² which advise 4 J kg^–1. This is supported by a recent study which showed that 2 J kg^–1 converted only about 50% of patients to a perfusing rhythm.¹² In contrast to previous recommendations, it is now recommended to give one shock followed immediately by uninterrupted CPR for 2 minutes without pausing to determine if another shock is required. Only in monitored witnessed onset of VF and immediate availability of defibrillation (first dose within 30 seconds) is a stack of up to three shocks (each 4 J kg^–1)^1,² without intervening CPR recommended. If ROSC has not occurred within 10 seconds of any of the 3 shocks CPR should be given. DC shock may be more successful if front and back placement of pads is used. Whatever position, use of pads rather than paddles enables minimal disruption to continuous external cardiac compression.

Failure of VF or pulseless VT to revert immediately to a perfusing rhythm with DC shock (4 J kg^–1) should be treated with another single DC shock (4 J kg^–1) after 2 minutes of CPR. Persistent VF or pulseless VT should be treated with adrenaline 10 mcg kg^–1 IV or IO or 100 mcg kg^–1 ETT followed by another single shock if necessary. Persistent (refractory) or recurrent VF or VT may be also treated with antiarrhythmics (amiodarone, magnesium) interspersed with single DC shocks followed by 2 minutes of CPR. Irrespective of other drug therapy, adrenaline should be administered every 3–5 minutes. Amiodarone is more efficacious than lignocaine for DC shock resistant VF and pulseless VT and is the preferred drug. The dose of amiodarone is 5 mg kg^–1 IV or IO over several to 60 minutes. It may be repeated to maximum of 15 mg kg^–1. If amiodarone is not available, lignocaine may be used in a dose of 1 mg kg^–1 IV or IO bolus followed by an infusion if successful at 20–50 mcg kg^–1 min^–1. Magnesium, 25–50 mg kg^–1 (0.10–0.20 mmol kg^–1) is indicated for polymorphic VT (torsade de pointes).

Management of pulsatile dysrhythmias

Bradysrhythmias

In all age groups, bradycardia is defined as a heart rate <60 min^–1 or rapidly declining rate with poor perfusion. Sinus bradycardia, sinus arrest with slow junctional or idioventricular rhythm and atrioventricular block are the most common preterminal arrhythmias in paediatric practice. Untreated, bradycardia will potentially progress to asystole. The treatment is reversal of the cause (hypoxaemia, hypotension, acidosis, hypothermia, intracranial hypertension) and, if unresponsive, adrenaline 10 mcg kg^–1 IV or IO or 100 mcg kg^–1 ETT. Bradycardia caused by vagal stimulation should be managed with cessation of the stimulus (e.g. oropharyngeal suctioning, laryngoscopy) and/or atropine 20 mcg kg^–1 IV or IO (minimum dose 100 μg). Persistent vagal-mediated bradycardia should be treated with adrenaline 10 mcg kg^–1 IV or IO. If facilities are available, pacing (oesophageal, transcutaneous, transvenous, epicardial) may be effective if sinus node dysfunction or heart block exist.

Tachydysrhythmias (Fig. 2.3.3)

Any heart rate above normal for age should be considered a tachydysrhythmia, particularly if associated with poor circulation and hypotension and if the patient has a history of cardiac disease, has had cardiac surgery or could have been poisoned with cardioactive drugs. Of course, such tachycardia may be the result, rather than the cause of poor circulation, i.e. sinus tachycardia (ST). It is important to determine the type and aetiology of the tachycardia, lest drug or other treatment exacerbate the situation. A history related to the tachycardia and a 12-lead ECG should be analysed carefully. If the diagnosis is not obvious, the rate and duration of the QRS are starting points to differentiate sinus tachycardia (ST), ventricular tachycardia (VT), supraventricular tachycardia (SVT) and wide QRS-complex SVT.

Fig. 2.3.3 Management of pulsatile tachydysrhythmias.

Pulsatile ventricular tachycardia

Haemodynamically stable VT may be treated with an antiarrhythmic agent such as amiodarone (5 mg kg^–1 IV over 20–60 minutes) or procainamide (15 mg kg^–1 IV over 30–60 minutes) or lidocaine (1 mg kg^–1 IV over 2–4 minutes). Note that both amiodarone and procainamide prolong QT interval and should not be given together. If torsade de pointes (twisting of the peaks) is present, magnesium (25–50 mg kg^–1, 0.1–0.2 mmol kg^–1 IV) may be used. If pulses are present but accompanied by hypotension and poor circulation, cardioversion is needed, in which case it should be synchronised at ≥2 J kg^–1 under sedation/anaesthesia.

Supraventricular tachycardia

SVT is the most common spontaneous arrhythmia in childhood and infancy. Some infants may tolerate this rhythm for long periods; however, it may cause life-threatening hypotension. It is usually re-entrant with a rate of 220–300 min^–1 in infants, usually less in children (approximately 180 min^–1). The QRS complex is usually narrow (<0.08 seconds), making it difficult sometimes to discern from sinus tachycardia. However, whereas ST is a part of other features of illness, SVT is a singular entity and whereas the rate in ST is variable with activity or stimulation, it is uniform in SVT and often of sudden onset and offset. In both rhythms, a P wave may be discernible.

If haemodynamically stable (adequate perfusion and blood pressure), initial treatment of SVT should be vagal stimulation. For infants and young children, application to the face of a plastic bag filled with iced-water is often effective, or alternatively submersion of the face into a slurry of ice and water in a bowl. Older children may be treated with carotid sinus massage or asking them to perform a Valsalva manoeuvre – such as blowing through a narrow straw. If unsuccessful, give adenosine initially at 100 mcg kg^–1 IV by rapid bolus (max dose 6 mg), increasing to 200 mcg kg^–1 or 300 mcg kg^–1. In older children, it is important to describe the transient feeling of ’chest heaviness or breathing difficulty or fearfulness‘ that may accompany adenosine administration, and/or precede the adenosine with a small amnestic dose of midazolam. If unsuccessful, give synchronised DC shock (cardioversion)¹³ initially at 0.5?1.0 J kg^–1 but subsequently up to 2 J kg^–1. If at the outset SVT is accompanied by haemodynamic instability, proceed to cardioversion (synchronised 1.0 J kg^–1) immediately, although vagal stimulation or adenosine (IV or IO) may be used, provided they do not delay cardioversion. Verapamil should not be used to treat SVT in infants and should be avoided in children because it induces hypotension by vasodilation and negative inotropic effect.

Wide QRS complex supraventricular tachycardia

SVT with aberrant conduction may cause a wide-complex QRS (>0.08 seconds) and thus may resemble VT. If the blood pressure is low or circulation deemed inadequate, the rhythm should be regarded as VT and treated with synchronised DC shock at ≥2 J kg^–1. If pulses are absent, the rhythm should be regarded as pulseless VT and treated accordingly with DC shock.

Post-resuscitation management

Supportive therapy should be provided until there is recovery of function of vital organs. This may require provision of oxygen therapy, mechanical ventilation, inotropic/vasopressor infusion, renal support, parenteral nutrition and other therapy for several days or longer. Recovery of infants and children is usually slow because cardiorespiratory arrest is often secondary to prolonged global ischaemia or hypoxaemia, which implies that other organs sustain damage before cardiorespiratory arrest. The cause of the CPA should be investigated and treated appropriately, e.g. sepsis or drug overdose. Particular care should be taken to ensure adequate cerebral perfusion with well-oxygenated blood. Hyperventilation to hypocarbic levels is contraindicated because of potential harmful cerebral vasoconstriction.

Survival and neurological outcome is better when deliberate hypothermia is used after cardiac arrest. ILCOR has recommended therapeutic hypothermia (32–34°C) for 12–24 hours for adults and children ¹ who remain unconscious with spontaneous circulation after out-of-hospital cardiac arrest when the initial rhythm was ventricular fibrillation, and suggested that for any other rhythm, or cardiac arrest in hospital, such cooling may also be beneficial. The optimal duration of such requirement, however, is unknown but clinical studies among newborns suggest 72 hours.¹⁴ Inadvertently hypothermic patients, provided temperature is above 32°C or greater should not be actively warmed and hyperthermia should be aggressively treated. If deliberate hypothermia is employed, shivering should be prevented with sedation and/or neuromuscular blockade. Seizures should be actively sought and treated with anticonvulsant.

Complications of CPR should be sought especially if secondary deterioration occurs. A chest X-ray should be obtained to check the position of the endotracheal tube, to exclude pneumothorax, lung collapse, contusion or aspiration and to check the cardiac silhouette. Invasive blood pressure measurement and periodic echocardiographic or bedside ultrasound examination are needed to specifically check contractility and to exclude a pericardial effusion. Measurement of haemoglobin, pH, gas tensions, electrolytes and glucose are important.

Cessation of CPR

Long-term outcome from paediatric CPR is poor, with approximately 5–10% of patients surviving out-of-hospital arrest ¹⁵ and 25–50% in-hospital cardiac arrest.^16,¹⁷ The decision to cease CPR should be based on a number of factors including the duration of resuscitation, its quality, response to treatment, pre-arrest status of the patient, remediable factors, likely outcome if ultimately successful, opinions of personnel familiar with the patient and, whenever appropriate, the wishes of informed parents. In general, unless hypothermia or drug toxicity exists, survival to normality is most unlikely if there has been a failure to respond to full CPR after 30 minutes and several doses of adrenaline, unless environmental hypothermia was an important aetiological or consequential factor. In the newly-born infant, discontinuation of treatment is appropriate if CPR does not establish a spontaneous circulation within 15 minutes.¹ Family members should be kept informed, allowed to be present or asked if they want to be present during resuscitation (see Chapter 2.1).