Paediatric advanced life support

Essentials

1
In the absence of signs of life, pulse check should be limited to 10 seconds and cardiopulmonary resuscitation (CPR) commenced immediately if no detectable pulse or heart rate <60 beats per minute (bpm). It has been established that diagnosis of cardiac arrest using palpation alone results in delays to initiation of resuscitation even amongst healthcare personnel.
2
The major causes of cardiopulmonary arrest in infants and children include any cause of hypoxaemia or hypotension or both. Remember to consider the 4Hs and 4Ts.
3
Aspects of CPR are different for ‘the newly born’, infant, child and large (older) child (see Chapter 4.5 , Neonatal resuscitation).
4
Bag-mask ventilation, effectively delivered, can replace the need for intubation until conditions are optimised for successful intubation.
5
Avoid hypoxaemia and hypotension during attempts at intubation.
6
The use of a checklist and a plan to manage the ‘can’t intubate, can’t ventilate’ situation are advised.
7
Obtain intraosseous (IO) access if you cannot cannulate a vein rapidly. This is a core skill for all clinicians treating sick children.
8
Restore intravascular volume with a balanced isotonic crystalloid solution (Ringers Lactate, Plasmalyte) or with 0.9% normal saline in aliquots of 10 mL/kg. (Resus UK 2021, ALSG 2021) Consider blood products early in haemorrhagic shock.
9
A decision to cease CPR should be based on a number of factors including the duration of resuscitation, response to treatment, prearrest status of the patient, remediable factors, likely outcome if ultimately successful, opinions of personnel familiar with the patient and, whenever appropriate, the wishes of the parents.

Introduction

This chapter will address the correct choice and use of equipment, medications and fluids required for advanced life support (ALS)/resuscitation of critically ill children. It will address management of arrhythmias, dysrhythmias and raise some of the challenges of paediatric ALS. It does not replace participation in a formal advanced paediatric life support (APLS) or paediatric advanced life support (PALS) course, which offer a structured standardised approach to the management of paediatric emergencies and synthesise knowledge gained through study of this section.

Definition of advanced life support

Paediatric advanced life support, or PALS, is the term used to summarise the application by trained practitioners, of resuscitation skills and knowledge to deliver care to the critically ill infant or child. This relates to the time before, during and after cardiac arrest, the aim being to intervene as soon as a problem is identified in order to prevent deterioration to cardiac arrest or if this is not possible, to manage it in as efficient and structured a manner as possible. The recommendations in this section are based on recent publications of the Australian Resuscitation Council, the European Resuscitation Council 2021, the American Heart Association, the UK Resuscitation Council 2021 update, and the International Liaison Committee on Resuscitation 2021. They are intended for use by medical and nursing personnel in hospital and by ambulance personnel in the field.

Knowledge gained in this chapter is best reinforced via participation in an APLS or PALS course, and via simulation to embed the structured approach to management of paediatric ALS.

Diagnosing cardiac arrest

In paediatric patients a structured, rapid assessment to a collapsed child is required. That initial assessment should focus on systematically checking for signs of life (verbal and physical stimulation, observe for movement, respiratory effort) followed by rescue breaths and a rapid (no longer than 10 seconds) pulse check and progression to CPR and basic life saving (BLS) if no heart rate is palpated or it is found to be under 60 bpm.

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 fraction of inspired oxygen (FiO ₂ ) should be regulated to yield arterial oxygen partial pressure in the normal range 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.

Numerous devices may be used to supply supplemental oxygen. The choice is dictated by the required FiO ₂ , cost, avoidance of CO ₂ rebreathing, imposed airway resistance and tolerance by the patient.

Nasal prongs/nasal catheters

These are easy to use, cheap and are well tolerated, especially in the preschool age group. The oxygen concentration delivered is between 25–40% and is dictated by factors such as minute ventilation, nasal patency and extent of mouth breathing. Flow is limited to 4L per minute. If using rates greater than 2L per minute for a prolonged period, oxygen should be heated and humified to minimise irritation to the nasal mucosa.

High-flow nasal cannula

High-flow nasal cannula (HFNC) refers to the delivery of a heated, humidified blended mixture of oxygen and air ranging from a controllable oxygen concentration of 21–100%. The rate of gas delivery exceeds the spontaneous inspiratory flow of the child. It is still unclear what the appropriate indications for HFNC are. It has demonstrated safety in children and infants and is easy to apply. HFNC works by removing the nasopharyngeal dead-space and through provided positive end-expiratory pressure (PEEP). The degree of PEEP used is dependent on the how snugly the cannula fit the nares, the gas flow rate and whether the mouth is open or closed. The application of a soother will often improve the efficacy of HFNC.

The use of ‘high-flow’ humidified oxygen as a means to provide continuous positive air pressure (CPAP) and thereby provide ventilatory support is being increasingly used for bronchiolitis and traditional indications for CPAP (respiratory syncytial virus (RSV) apnoea, apnoea of prematurity, congestive heart failure, children with neuromuscular disease, etc.). The evidence for the use of HFNC outside of hypoxic respiratory failure is limited. Flow rates of 2 L/minute per kg have been studied in infants with bronchiolitis and appear safe. For older children, a suggested protocol is 2 L/minute per kg for the first 10 kg body weight plus 0.5 L/min per kg for each kg body weight after to a max of 50 L/minute.

Inhaled bronchodilators cannot be given on top of HFNC as the majority of the patient’s inspiratory gas comes from the nasal cannula displacing any aerosolised medications.

Oxygen masks

Semirigid face masks of the Hudson type can supply approximately 35–70% O ₂ at flow rates of 4–15 L/minute. 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 FiO ₂ , 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% O ₂ but, likewise, may cause rebreathing if the flow rate does not match PIFR during respiratory distress.

Ventilation

Ventilation should be applied as soon as practicable. External ventilation can be applied to the child using three standard pieces of equipment: a face mask, endotracheal tube (ETT) or laryngeal mask airway (LMA). Methods of ventilation to interface with these three pieces of equipment are the self-inflating bag, T-piece devices and mechanical ventilators.

Self-inflating mask ventilation (bag-valve-mask)

This is usually the first technique employed to artificially ventilate a child using a self-inflating bag or T-piece device. 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. Two person–mask ventilation, where resources allow, is recommended for the initial resuscitation. This allows the first provider to establish a good seal between the mask and the face. Successful ventilation is dependent on achieving good chest rise at an appropriate age-adjusted rate.

Face masks are of two types; either circular or conformed to the child’s face. They may be air filled or made of soft plastic and are clear to enable caregivers to observe the face for cyanosis and detect vomiting.

Insertion of an oropharyngeal (Guedel) airway along with chin lift or jaw thrust may be necessary to facilitate bag-mask ventilation; however, this should only be attempted in children who are obtunded and have an absent gag reflex.

Self-Inflating bags

These bags are portable, light weight, do not require a gas source to operate and come in three sizes: 250, 500 and 1500 mL. The Laerdal series typifies these devices and is available in single-use disposable versions. The 250 mL bag is only suitable for use in small infants. Rebreathing is prevented by a one-way duck-bill valve, spring disk/ball valve or diaphragm/leaf valve. Pressure is simply and easily generated by squeezing the bag but can be difficult to regulate, potentially causing stomach distension or pneumothorax. A pressure-relief valve is often present and opens at 35 cm H ₂ O (3.5 kPa) which may be required to be overridden for high-resistance/low-compliance lungs. Supplemental oxygen is connected to the resuscitation bag and a reservoir bag may or may not be present. There is no positive end-expiratory pressure provided by self-inflating bags, but most have a provision to attach a separate PEEP valve for this purpose. With Laerdal and Partner bags, negligible amounts of oxygen (0.1–0.3 L/minute) issue from the patient valve when 5–15 L/minute of oxygen is introduced into bags unconnected to patients. Although it is possible to spontaneously breathe through the bag, the one-way valves located within the circuit makes the resistance significant; therefore, it should not be used for the purpose of supplying supplemental oxygen to the spontaneously breathing child. The patient valve is unlikely to open unless the mask is sealed well on the face. 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/minute to the infant resuscitator bag, the delivered gas is 85–100% oxygen without the use of the reservoir bag.

T-Piece devices

These are small machine devices that generate a positive inspiratory and expiratory pressure that can be adjusted and set according to an inbuilt pressure gauge. They are typified by ‘Neopuff’ and ‘NeoPIP’ devices. They are dependent on a gas source and use a specific circuit that attaches to the mask or ETT. The thumb is used to press a valve and deliver the inspiratory pressure for as long it is held and then released to allow expiration. They are commonly used in neonatal resuscitation and are appropriate for use in small infants.

T-piece devices have the benefit of being able to deliver a consistent pressure during inspiration but can still deliver large volumes of gas, potentially causing gas distension of the stomach or worsening of any pneumothorax.

Flow-Inflating bags

These are designed to give either positive pressure ventilation, or due to the absence of any valves, to allow a patient to breathe spontaneously. They are exemplified by Jackson-Rees modified Ayre’s T-piece and are used mostly in the anaesthetic environment. They are difficult to use in resuscitation settings and require specific training. Certain flow-inflating bags come with an adjustable pressure-limiting (APL) valve, typified by the Mapleson C-circuit. These have the advantage of requiring less training to use but allow the provider the ability to provide an oxygen concentration of 100% and the flexibility to increase the resistance on the APL valve such that they can deliver CPAP or positive pressure ventilation as required.

Rates and ratios of external cardiac compression and ventilation in advanced life support

The techniques of external cardiac compression and expired air resuscitation (mouth-to-mouth) or rescue breathing are described in Chapter 2.2 . The recommended ratio of external cardiac compression to ventilation in basic life support by a single rescuer is 15:2.

In order to achieve effective ventilation during CPR, the provider should apply a sufficiently long inspiratory time, e.g. at least 1 second and good chest rise should be seen. CPR in children should always be accompanied by ventilations. Compression only CPR is not recommended in children (<18 years of age). Further detail regarding chest compressions including hand positioning can be found in Chapter 2.2 of this textbook.

In ALS, the recommended ratio of compressions to ventilation by two healthcare rescuers is 15:2, which, if repeated five times in 1 minute, with pauses for ventilation by bag-mask, would yield approximately 75 compressions and 10 ventilations per minute. Once a child has been intubated during a cardiac arrest, ventilations can be asynchronous and chest compressions continuous (only pausing every 2 minutes for rhythm check). In this case, ventilations should approximate to the lower limit of normal rate for age, e.g. breaths/minute: 25 (infants), 20 (>1 y), 15 (>8 y), 10 (>12 y) (ERC 2021 PLS). The use of a mechanical ventilator, e.g. volume control, can be used during cardiac arrest provided the pressure limits are disabled. Chest compression synchronised ventilation has shown promise in adult CPR but paediatric studies have not been conducted.

There is currently no evidence to recommend for or against the use of PEEP during a paediatric cardiac arrest.

If an LMA is being used, there are no data to indicate if ventilation is effective using this device during continuous CPR, and it is recommended to pause chest compressions to deliver breaths as per mouth-to-mouth and bag-valve-mask techniques.

Interruptions to chest compressions should be minimised. Every time cardiac compression is interrupted, cardiac stroke volume and the coronary and cerebral perfusion pressure approach zero and then several successive compressions are required to reestablish the stroke volume and pressure achieved before interruption. Necessary interruptions to cardiac compressions should be minimised by coordinated planning; for example, to analyse the cardiac rhythm or to give direct-current shock. Effort must be directed towards minimising ‘hands-off time’ during requirement for cardiac compression.

Advanced airway support

Endotracheal intubation

The decision to intubate should always be balanced against the associated risk of the procedure. If adequate bag-mask ventilation is being achieved during a cardiac arrest, endotracheal intubation may be deferred. If bag-mask ventilation is inadequate and/or intubation is deemed necessary, this procedure should only be performed by a competent provider, following a well-defined procedure, and having the necessary materials and drugs.

The advantages of establishing a definitive airway include maintaining airway patency, achieving oxygenation and ventilation and reducing the risk of pulmonary aspiration.

Preventing hypoxaemia and hypotension are important during intubation. Multiple attempts or prolonged laryngoscopy should be avoided. Prior to intubation, potential difficulties should be anticipated, and alternate airway management techniques should be planned. If difficulty is experienced or the child is desaturating, oxygenation should be reestablished with bag-mask ventilation before a reattempt at intubation. The oral route for endotracheal intubation is preferred during an emergency. Nasal intubation may be performed in the elective setting.

Regurgitation of gastric contents is common during cardiac arrest. A nasogastric tube should be inserted and aspirated to prevent this and to relieve any gaseous distension of the stomach sustained during bag-mask ventilation.

Correct placement of the ETT in the trachea must be confirmed immediately after intubation. Mainstem bronchus or oesophageal intubation will result in hypoxaemia and hypocarbia. There is no substitute for direct visualisation of the passage of the tube through the vocal cords. Additional clinical assessments of ETT position include observation of chest rise, auscultation of bilateral breath sounds and misting of the tube. Continuous waveform capnography is recommended as the most reliable method of confirming and monitoring correct placement of an ETT (AHA). Measurement of end-tidal expiratory pressure of carbon dioxide (EtCO ₂ ) using capnography provides a noninvasive estimate of cardiac output and organ perfusion during cardiac arrest. Currently there is no single CO ₂ value that can be used as a target or as an indication to continue or discontinue CPR. However, a sudden rise of ETCO ₂ during CPR is suggestive of return of spontaneous circulation (ROSC).

Capnography may also be helpful for early detection of obstruction or misplacement of the tube.

Endotracheal tube size ( Table 2.3.1 )

Cuffed ETTs should be used during paediatric life support.

Uncuffed ETTs were traditionally used in children because the airway surfaces of their epiglottis and cricoid are lined with loose areolar connective tissue that is prone to oedema formation. It was thought that use of a cuffed ETT could promote laryngeal and tracheal injury, as well as impair tracheal mucosal blood flow and compress the mucosa within the unyielding cricoid ring. , , This could potentially result in post-extubation laryngeal oedema and or tracheal stenosis.

Research has demonstrated, however, that an uncuffed ETT with a tight seal will exert undue pressure on the laryngeal structures, causing laryngeal injury. Conversely, an uncuffed tube with large leakage leads to unreliable monitoring of the ventilatory parameters, exhaled volumes and end-expiratory gases.

In recent years, therefore, the use of cuffed ETTs has become the standard of care. Cuffed tubes have been shown to reduce the risk of aspiration and improve ventilation as well as end-tidal carbon dioxide monitoring. In addition, the need to exchange the tube is also reduced, with no increased risk of post-extubation stridor compared with uncuffed ETTs. ^, ^,

Evidence has further demonstrated that the use of appropriately designed cuffed ETTs, with cuff pressure control and the correct size of tube, the likelihood of a successful fitting at the first attempt is much higher than with uncuffed tubes. ^,

In a resuscitation scenario, a cuffed ETT should be used, and cuff inflation pressure should be monitored and limited to the minimum volume which delivers no leakage, according to manufacturer’s recommendations (usually <20 to 25 cm H ₂ O) (ERC 2021 PLS). Appropriate-sized cuffed tubes a may be estimated by the formula: size (mm) = age (years)/4 + 3.5.

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