Acute pain in children is one of the most common reasons for presentation to the emergency department (ED).¹ Pain resulting from injury, illness or necessary medical procedures is associated with increased anxiety, avoidance behaviour, systemic symptoms and parental distress. Painful experiences involve the interaction of physiological, psychological, behavioural, developmental and situational factors. Children with painful conditions can be difficult to assess and are often still underassessed and undertreated. Children often receive less analgesia than adults and the administration of analgesia varies by age, with our youngest patients at the highest risk of receiving inadequate analgesia.^2,³

Children’s pain is underestimated because of a lack of adequate assessment tools and the inability to account for the wide range of children’s developmental stages. Pain is often undermedicated because of fears of oversedation, respiratory depression, addiction, and unfamiliarity with use of sedative and analgesic agents in children.³

Emergency department staff should be proficient in the assessment and safe management of pain in children. Early and appropriate analgesia may be best achieved by using a systematic approach with well-developed pain management educational programs, specific pain management policies, and benchmarked standards for time-to-analgesia within the ED.

Definitions of terms are outlined in Table 20.1.1.

Analgesia Relief of the perception of pain without sedation Anxiolysis Relief of apprehension without sedation or analgesia Sedation Lessening of awareness of the environment and or pain perception Anaesthesia (general) Complete loss or awareness of the environment accompanied by loss of protective reflexes Procedural sedation A technique of administering sedative or dissociation agents, with or without analgesics, to induce a state that allows the patient to tolerate unpleasant procedures while maintaining cardio-respiratory function PSA Procedural sedation and analgesia is intended to result in a depressed level of consciousness but one that allows the patient to maintain airway control independently and continuously EDPS Emergency Department Procedural Sedation

Assessment and measurement of pain

Pain is a subjective multifactorial experience and should be treated as such.² Pain may be influenced by age, race, gender, culture, emotional state, cognitive ability, expectations and prior experience. Assessment of pain should be individualised, continuous, measured and documented. Over the last 20 years, pain assessment and measurement tools have been developed that are suitable for children of different ages and developmental stages. A definitive review of pain measurement in infants and children has not been published.

Accurate assessment requires a detailed pain history and consideration of the complexity of the child’s pain perception and the influence of situational, psychological and developmental factors. Because of its subjective nature, pain is best assessed using the child’s self-report, especially in older children’s pain. Observation of the child’s behaviour should be used to complement self-report tools. Four useful means of recognising pain in children are outlined in Table 20.1.2.

1. The child’s self-report of pain

2. Behavioural changes, e.g. crying, guarding, facial grimacing

3. Physiological changes, e.g. pallor, tachycardia, and tachypnoea

4. Pathophysiological process, e.g. fracture or burn

Observational assessment scoring may be useful when the child is too young or self-report is not possible, e.g. children with cognitive impairment. Pain ratings provided by parents or regular carers may be used;⁴ however, whilst there is good correlation between the child’s and the parent’s assessment of pain intensity, parents tend to underscore more severe pain being experienced by their children.⁵ Physiological measures (e.g. heart rate and respiratory rate) may be useful in pain assessment in non-verbal or sedated children but may be confounded by stress reactions. For example, the infant who is hungry or frightened may give an inappropriately high score.

Specific pain assessment tools using behavioural observation have been developed for neonates and non-verbal or cognitively impaired children (e.g. FLACC and NCCPC-R tools). Common behavioural indicators of pain include: crying or vocalisation; facial expressions; body language and posture; agitation and consolability.

An understanding of the pathophysiological process can also give the clinician a surrogate indication of severity of pain.

Pain scores are typically standardised on a 0–10 scale. Pain scores are documented with other observations and vital signs. Some common pain rating scales appropriate to age are outlined in Table 20.1.3.

Table 20.1.3 Pain scoring

Procedural sedation and analgesia: a structured approach

The goal of procedural sedation in the ED is to provide a suitable level of sedation that enables successful completion of a necessary procedure whilst minimising the risk of adverse events to the patient and enabling early safe discharge home from the department. In order to achieve this goal, consideration needs to be given to the health status of the patient, the procedure to be performed – particularly the duration and likely amount of pain – selection of an appropriate drug or combination of drugs, provision of non-pharmacological techniques, patient preparation and the informed consent and understanding of the parent(s) or carer(s).

Critical incident analysis of adverse sedation events in paediatrics has identified inadequate medical evaluation, inadequate monitoring during or after the procedure, inadequate skills in problem recognition and timely intervention and lack of experience of the practitioner with a particular age group or with an underlying medical condition as factors associated with adverse events in paediatric sedation.⁶

The development and implementation of procedural sedation guidelines in emergency departments, addressing quality of care for the patient, are associated with practice improvements ⁷ and the lessening of adverse events and complications.⁸^–¹⁶

The formulation of a sedation plan and sedation policies can be divided into:

Pre-procedure assessment.

Procedure management.

Post-procedure management.

Pre-procedure assessment and management

Health status of the patient is essential to identify elements of medical history or any current illnesses that may impact upon the safety of procedural sedation, choice of agent or consideration of alternative techniques.

Important factors to consider are listed in Table 20.1.4.

• Current illness – URTI, active asthma, altered conscious state, haemodynamic compromise

• Age under 12 months (especially <3 months)

• Airway abnormalities – craniofacial deformities, tracheomalacia, predicted difficult airway

• Cardiac conditions – congenital heart disease, arrhythmias, cardiac failure

• Neurological conditions – seizure disorders, raised intracranial pressure

• Respiratory conditions – active asthma, upper or lower respiratory tract infections, respiratory failure

• Hepatic and renal disorders

• Prior history of failure of sedation

• Prior adverse event due to sedation, analgesia or anaesthesia

Children aged less than 1 year, and particularly the very young baby, have a higher incidence of hypoxic complications with procedural sedation and in very young infants consideration should be given to general anaesthesia with formal airway management.

While the presence of active asthma or upper respiratory tract infection is associated with a higher risk of complications, including laryngospasm, in patients undergoing general anaesthesia ¹⁷ it is unclear whether this increased risk also applies to procedural sedation. Most authorities assume that it does and tailor the sedation plans accordingly.

Further history that needs to be obtained includes current medications, allergies and fasting status.

Pre-procedure fasting guidelines are a feature of most protocols developed for procedural sedation in children and aim to minimise the risk of pulmonary aspiration. Both the American Academy of Pediatrics and the American Society of Anesthesiologists (ASA) list specific fasting times for solids and liquids that vary from 2 hours to 6–8 hours, depending on the age of the child.^18,¹⁹ However, these recommended times were a result of expert consensus opinion and are not specifically directed at patients in the unique ED setting. In fact, aspiration associated with paediatric procedural sedation has not been reported in the literature and there is no compelling evidence to support specific pre-procedure fasting periods for either liquids or solids.²⁰^–²³

Whilst some EDs use a general fasting guideline of 2 hours for clear liquids and 4–6 hours for solids or liquids that are not clear (including milk), a number of EDs do not have strict fasting guidelines. The risk of aspiration with ED procedural sedation is likely to be significantly lower than that associated with general anaesthesia and the requirement for fasting remains a subject of debate. Fasting requirements should be adjusted for individual cases, following consideration of an individual patient’s risks of aspiration and the nature and urgency of the sedation.²³

Physical examination should include patient weight, baseline vital signs including oxygen saturation, assessment of conscious state, evaluation of the airway and examination of the cardiovascular and respiratory systems.

The ASA physical status categories developed for general anaesthesia are not generally used for ED procedural sedation as it is unclear how they extrapolate to this setting.²⁴ Following risk assessment and generation of a sedation plan, this plan should be discussed with the child’s parent or carer to obtain informed consent. A clear explanation of the sedation plan and what is to happen for the older child is often useful in an effort to allay anxiety and optimise co-operation.

The expected effects on the child, risks, benefits, alternatives and need for monitoring and observation during and after the procedure prior to safe discharge must be discussed with the parent or guardian. As the expected effects, risks and recovery times prior to discharge will vary greatly between different agents, the use of a standardised procedural sedation consent form for all sedative drugs is suboptimal. It is recommended that drug or drug combination-specific consent forms should be generated that reflect the individual features of the different agents, to clearly identify that these issues have been discussed with the child’s parent. An alternative to this involves standard documentation in the medical record that agent-specific issues were discussed with the parent(s)/carer(s).

In most EDs there is a policy that informed consent for procedural sedation is obtained in written form unless it is employed in a life- or limb-threatening situation.

Medications

A medication order containing all sedative drugs to be used should be recorded on the appropriate medication chart or sedation record, and the doses, route and time of administration should also be recorded.

Reversal drugs and life-support drugs should also be available (Table 20.1.5).

Equipment^a

• Oxygen source, masks and tubing

• Suction source and suction devices

• Self-inflating bag–mask device

• Oral and nasal airways

• Endotracheal tubes and difficult airway management devices

• Laryngoscopes

• Defibrillator with paediatric paddles

• ECG monitor

• Non-invasive blood pressure measurement device

Intravenous cannulation equipment

• Oxygen saturation monitor

• Delivery system and scavenger device for continuous nitrous oxide administration

• End-tidal carbon dioxide monitor (ETCO₂)

Drugs^b

• Epinephrine (adrenaline)

• Atropine

• Lidocaine

• Dextrose 10%

• Reversal agents – naloxone and flumazenil

• Hydrocortisone

a All equipment must be available in varying sizes appropriate to patient population.

b Correct weight-based dose information should be readily available.

Management during the procedure

A number of recommendations and statements from clinical authorities have been published detailing particular aspects of required personnel, monitoring equipment, patient preparation for procedural sedation in children both inside and outside of the operating theatre.²⁵^–²⁷

It is essential that the team administering procedural sedation is aware that it is impossible to reliably predict in advance the level of sedation that will occur in an individual patient given a sedative drug or combination of drugs. Regardless of the intended level of sedation or route of administration, the sedation of a patient represents a continuum, and may result in the loss of the patient’s protective reflexes – a patient may move easily from a light level of sedation to deep sedation. As a consequence, it is imperative to plan for situations where the child becomes sedated to a far greater level than intended or experiences significant cardio-respiratory complications of sedation.

Accordingly, well-understood policies and procedures detailing the requirements for procedure management should be developed by EDs providing procedural sedation to children. Table 20.1.6 details the important elements of the conduct of procedural sedation management.

5. Patient preparation and consent

6. Monitoring

7. Recovery

8. Documentation

9. Discharge criteria

Monitoring, observations and recording

The most important element of monitoring during sedation is close, continuous observation of the patient.

Continuous oxygen saturation monitoring is recommended in all forms of procedural sedation as is continuous observation of colour, airway and rate and depth of ventilation.

Capnography

Capnography provides a more sensitive means of identifying respiratory depression or airway complications resulting from sedative agents than conventional monitoring and observation, but has been underutilised.²⁸

With abnormalities in ventilation that are detectable by capnography and then only later evolve into the typical clinical manifestations of respiratory depression, apnoea, or airway obstruction.²⁹^–³³ Oxygen desaturation is often the last sign of the complication, particularly when supplemental oxygen has been administered.²⁹

Observation and recording of heart rate, blood pressure, respiratory rate, conscious level or sedation score, O₂ saturation and ETCO₂ should be recorded prior to the procedure, after sedative drug administration and at 5–10-minute intervals during the procedure, depending on the level of sedation achieved. Times of administration, drugs given, dosages and routes of administration of drugs should be clearly recorded on a time-based observation chart.

Interventions performed, such as provision of supplemental oxygen or basic airway management should also be recorded.

Supplemental oxygen

The use of supplemental oxygen is largely unstudied in children undergoing procedural sedation in the emergency department.^32,^34,³⁵

The addition of supplemental oxygen has the potential to mask respiratory depression as hypoxia may not manifest even in the presence of significant hypoventilation. Use of ETCO₂ monitoring is recommended when supplemental oxygen is administered as changes in ETCO₂ associated with respiratory depression are detectable before the onset of hypoxia.³⁴

Many physicians use supplemental oxygen coupled with ETCO₂ monitoring with patients who are undergoing deep sedation.

Sedation scores

There is no universally validated and accepted score for recording the depth of sedation in patients undergoing procedural sedation in the emergency department.

Benefits of the use of a valid scoring method include the monitoring and recording of depth of sedation during episodes of procedural sedation along with assisting in standardisation of terminology and classification of sedation depth, particularly in clinical audit and research, looking at the effectiveness and adverse event profiles of different drugs at different doses.

These scores are observational in nature and are recorded during the episode of sedation.

A commonly used sedation score is the Children’s Hospital of Wisconsin Sedation Scale.⁹

The scale has seven levels of sedation ranging from 6 to 0:

6:anxious, agitated or in pain;

5:spontaneously awake without stimulus;

4:drowsy, eyes open or closed, but easily arouses to consciousness with verbal stimulus;

3:arouses to consciousness with moderate tactile or loud verbal stimulus;

2:arouses slowly to consciousness with sustained painful stimulus;

1:arouses, but not to consciousness, with painful stimulus;

0:unresponsive to painful stimulus.

Deep sedation is commonly defined as a score of 0–2 and moderate sedation as a score of 3.

The Modified Ramsay Sedation Score ³⁶ is also commonly used and ranges from a score of 1: awake and alert, through to a maximum score of 8: unresponsive to external stimuli, including pain.

Bispectral index monitoring

The advent of bispectral index (BIS) monitoring to measure the depth of anaesthesia in patients in the operating room may potentially be a useful adjunct in procedural sedation in the ED. ^29,³⁷^–³⁹

Further studies using this index will better define what role an objective measure of sedation level may play in reduced complications of oversedation along with avoidance of inadequate sedation during procedures.

Post-procedure management

It is imperative that children are closely observed and monitored in an appropriate environment following procedural sedation. Children vary greatly in their speed of recovery from sedation. This is also influenced by the drug(s) used, the route of administration and the total dosage given.

The period immediately following the completion of the procedure – with cessation of the painful or unpleasant stimulus – is a period during which cardiorespiratory depressant effects of the sedation drugs may be most apparent and it is during this time that there is an increased risk of complications.⁴⁰

If the child is moved to another area following the completion of the procedure, they should continue to be closely observed and monitored by a suitably experienced nurse and resuscitation equipment should still be immediately available if needed. The frequency of vital signs observation can gradually lessen as the child awakens and the risk of cardiorespiratory complications diminishes. Generally, the frequency of vital signs observation will lessen from 5-minutely to 30-minutely as the child returns to their pre-sedation state.

Post-procedural observations should be recorded on the same time-based observation sheet as used during the procedure and evidence of improvement in conscious level and activity should also be recorded.

It is important to have standard discharge criteria, which must be met by the child prior to leaving the ED, and nursing staff caring for the child must be familiar with these. Suggested discharge criteria are listed in Table 20.1.7.

• Normal age-specific vital signs

• Child has regained pre-sedation conscious state and communication skills

• Child is able to ambulate independently (relative to age and pre-sedation ability)

• Child is able to tolerate oral food or fluids

• Post-procedure analgesia is satisfactory

• Parent or carer has been provided with post-discharge instructions, understands them and is capable of following them

Development of a standard post-procedural sedation discharge instruction sheet, which includes advice regarding diet, activities, observation, and sleeping in the 24 hours after discharge, along with specific signs to watch for and a direct ED contact number, is also valuable. The adult taking responsibility for the child after discharge should receive a copy prior to leaving and staff should both check that they understand it clearly and answer any questions about it that they may have.

Finally, follow-up arrangements relating to the procedure performed (e.g. review of wound, suture removal) should also be provided before discharge.

Complications of paediatric procedural sedation

Paediatric procedural sedation can be hazardous and both mortality and significant morbidity have been reported in the literature.⁴¹^–⁴³

Studies of procedural sedation in EDs with adherence to published guidelines and involvement of staff trained in sedation and paediatric resuscitation techniques have yielded variable rates of complications of 2.3–25%, with the incidence of serious complications such as laryngospasm, pulmonary aspiration or cardio-respiratory arrest being extremely low.⁴³^–⁴⁵

Establishing accurate adverse event and complications rates of different agents from the available literature has been difficult because of the difficulty in aggregating results from previous studies that have used varied terminology to describe the same adverse events and outcomes.^46,⁴⁷

In 2009, a Consensus Panel on Sedation ⁴⁶ proposed a standardised terminology and reporting methodology for adverse events in EDPS in children. Moving away from the traditional event- and threshold-based definitions of an adverse event (e.g. oxygen saturation <92%), the Panel proposed reporting based on whether a particular event required an intervention to be performed by the clinician, i.e. whether the event was clinically relevant rather than simply transient, self-limiting and without clinical sequelae. Adoption of such standardised reporting guidelines by researchers will provide data that may be readily compared and aggregated across a variety of drugs, drug combinations, sedation providers and sedation locations.

A number of recent studies have reported on large cohorts of children undergoing procedural sedation.

The Paediatric Sedation Research Consortium reported on the nature and frequency of adverse events in 30 000 children receiving sedation and/or anaesthesia for diagnostic and therapeutic procedures outside of the operating room.⁴³ The overall reported adverse event rate was 1 in 29 cases (3.4%) and the rate of unplanned treatments was 1 in 89 cases (1.1%) Serious adverse events were rare and there were no deaths. One case of cardiac arrest and one case of pulmonary aspiration were reported. Conversely, more minor but potentially serious adverse events were not rare. Oxygen desaturation below 90% was the most common adverse event reported, with an incidence of 1.5%. Vomiting was common and occurred in 1 in 200 sedations (0.5%). Approximately 1 in 400 procedures were associated with stridor, laryngospasm, wheezing or apnoea and 1 in 200 sedations required airway and ventilation interventions ranging from bag–mask ventilation (0.6%), to oral airway placement (0.3%) to emergency intubation (0.1%). The same research group has also reported the incidence and nature of paediatric sedation with propofol outside the operating room using a large database of 49 836 propofol sedation encounters.⁴⁴ There were no deaths reported. Cardiopulmonary resuscitation was required twice and there were four episodes of pulmonary aspiration. Less serious events were reasonably common, with oxygen desaturation below 90% for more than 30 s having an incidence of 1.5% and apnoea, airway obstruction, wheezing, stridor or laryngospasm occurring at a rate of 1.6%, with a reported rate of unplanned airway interventions (from simple airway manoeuvres to emergency intubation) of 1.5%, which equates to 1 in 70 propofol sedations requiring airway and ventilation interventions.

Metanalyses of predictors of adverse events in procedural sedation with ketamine in children have reported an overall incidence of airway and respiratory adverse events of 3.9% from 8282 episodes of ketamine sedation. The rate of unplanned airway interventions was not reported and many of these observed adverse events required no intervention. The overall incidence of emesis, any recovery agitation, and clinically important recovery agitation was 8.4%, 7.6%, and 1.4%, respectively.^45,⁴⁸

The majority of significant adverse events in paediatric procedural sedation are related to airway obstruction, hypoventilation requiring stimulation, supplemental oxygenation and/or a short period of assisted ventilation by bag–mask device. Paradoxical excitation (benzodiazepines) or clinically significant recovery agitation (ketamine) may require specific management.

Table 20.1.8 lists adverse events and complications associated with paediatric procedural sedation.

• Sedation failure

• Paradoxical excitation

• Recovery agitation

• Vomiting

• Airway obstruction requiring suction, repositioning or use of an airway adjunct.

• Hypoxia

• Hypercarbia

• Apnoea

• Hypoventilation requiring supplemental oxygenation and/or assisted ventilation

• Laryngospasm

• Bronchospasm

• Pulmonary aspiration

• Hypotension

• Bradycardia/tachycardia/cardiac arrhythmias

• Cardiorespiratory arrest

• Allergic reactions

• Over sedation

• Seizures

Adherence to published guidelines recommending minimum requirements for personnel, patient monitoring and assessment for safe discharge has been shown to reduce adverse events associated with procedural sedation in children.⁹

In particular, the generation of an individual sedation plan comprising an individual risk assessment with documentation of variables such as fasting status, quantitative sedation scoring, time-based recording of vital signs and pulse oximetry combined with standardised recovery and discharge criteria and use of a standardised record has been shown to progressively reduce risk in procedural sedation, particularly in those children requiring a deep level of sedation.⁹

Non-pharmacological methods

A balanced multidisciplinary approach using pharmacological and non-pharmacological strategies is essential to providing optimal analgesia and sedation for the child. Non-pharmacological techniques can be particularly useful in pain management (whether or not medications are used as well) as they are free of side effects and may be utilised before, during and after painful procedures. The planning of procedures for children in the ED should include age-appropriate psychological interventions, such as distraction techniques. Distraction reduced self-reported pain following needle-related procedural pain.⁴⁹ Age-appropriate distraction techniques reduced situational anxiety in older children and lowered parental perception of distress in younger children undergoing laceration repair.⁵⁰ A child’s anxiety and co-operation are affected by age, anxiety of the parent and previous medical experiences. Toddlers are very distractible and storytelling and guided imagery are very effective methods. Some useful non-pharmacological strategies are outlined in Table 20.1.9.

Environment

• Calm friendly non-clinical atmosphere

• Toys, mobiles, pictures and videos

Psychological

• Parental presence

• Age-appropriate communication

• Clear confident instructions

Cognitive–behavioural

• Distraction techniques

• Hypnosis and biofeedback

• Art/stories

• Music/video/TV

• Interactive computer games

• Guided imagery

• Muscle relaxation and deep breathing techniques

• Reinforcement of coping behaviours

Physical

• Massage/rubbing

• Comfort swaddling (infants)

• Heat/cold techniques

• Immobilisation and elevation (injured part)

Breast-feeding

• Comforter (favourite blanket/soft toy)

Pharmacological methods

Some of the most commonly used agents are listed in Table 20.1.10.

Classification Doses Comments Pure analgesics Paracetamol 15–30 mg kg^–1 PO/PR (<3 months 10 mg kg^–1) 30 mg kg^–1 stat. only as a single dose (check no recent doses of paracetamol) Ibuprofen (NSAID) 5–10 mg kg^–1 PO Liquegesic Co paracetamol/codeine mixture (e.g. Painstop®) Dose based on paracetamol content Oxycodone 0.1 mg kg^–1 PO Better analgesia and fewer side effects than codeine Pure sedatives Midazolam 0.05–0.15 mg kg^–1 IV/IM; 0.5–0.75 mg kg^–1 PO; 0.3–0.5 mg kg^–1 IN Paradoxical excitement reaction in 10% of children when used PO or IN Sedative/analgesics Morphine 0.1–0.2 mg kg^–1 per dose (>3 months) IV, IM 0.05–0.1 mg kg^–1 per dose (<3 months) IV, IM Infusion (>3 months) 0.01–0.04 mg kg^–1 hr^–1 Cardio-respiratory depression with IV/IM doses IV dose preferred Fentanyl 1.5 mcg kg^–1 per dose Nitrous oxide 50:50 mix inhalation agent (ENTONOX®);
N₂O continuous flow variable mix 30–70% with oxygen Rapid onset; continuous flow delivery system allows use in young children/short duration of action. Vomiting can occur; contraindicated with pneumothorax/chest injuries Dissociative agent Ketamine 1–2 mg kg^–1 IV; 2.5–4.0 mg kg^–1 IM; 5–10 mg kg^–1 PO Excellent safety profile in selected patients undergoing painful procedures; contraindicated in head injury, seizure disorders, ocular injuries Sedative/hypnotic agent Propofol 0.5-3.0 mg kg⁻¹ induction dose (titrate slowly to achieve desired sedation depth), halve the induction dose for top-up dosing Median dose 0.75 mg kg⁻¹ when used with adjunctive analgesia. Respiratory depression is the most common adverse effect Local anaesthetic agents Injectable Lidocaine 1% or 2%; 3 mg kg^–1 maximum dose without adrenaline (epinephrine); 7 mg kg^–1 maximum dose with adrenaline Pain of injection can be minimised by using small needles (e.g. 31G), slow infiltration, infiltrating through wound edges, pre-treatment with topical LA, buffering and warming Levobupivicaine or bupivacaine 3 mg kg^–1 (maximum dose) Slower onset, longer duration of action compared with lidocaine; useful for nerve blocks Prilocaine 0.5% solution common; 2.5–3.0 mg kg^–1 Safe agent for intravenous regional anaesthesia (Bier’s blocks) Topical Surface EMLA® Eutectic mix of lidocaine 2.5% and prilocaine 2.5% Requires 60 minutes post-application to achieve satisfactory dermal anaesthesia AnGel®/Ametop® Amethocaine 4% Requires 30–45 minutes post- application to achieve satisfactory dermal anaesthesia Laceraine® Laceraine® solution is a mixture of 4% lidocaine, 0.5% tetracaine and adrenaline 1:1000 Contains adrenaline so cannot be used in end arteriole regions, e.g. digits, penis; requires > 20 minutes of good contact with wound to provide anaesthesia; may require supplementation with small doses infiltrated LA Reversal agents Naloxone 10 mcg kg^–1 IV May need to repeat doses Flumazenil 0.02 mg kg^–1 IV

LA, local anaesthetic; IM, intramuscular; IN, intranasal; IV, intravenous; PO, per oram; PR, per rectum.

Pure sedative agents

Sedative agents relieve anxiety but not pain. They may reduce the child’s ability to communicate pain and discomfort and a common side effect is paradoxical hyper-excitability. They are useful for painless diagnostic studies and, when used in combination with opioids or nitrous oxide, can produce a state of deep sedation.

Oral analgesic agents

Paracetamol is usually the first line of therapy for mild to moderate painful conditions. It can be given orally and rectally. Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, are usually second-line therapy and have excellent analgesic and anti-inflammatory properties, which may enhance the effects of paracetamol.

Oxycodone and codeine

Oral codeine has traditionally been used for moderate to severe pain; however, evidence from recent work shows that oral oxycodone produces greater pain relief compared with codeine.⁵¹Oxycodone also has a better side effect profile with less itching, less nausea, and fewer allergic reactions. Codeine is a prodrug of morphine and nine percent of children do not have the liver enzyme CYP2D6 to convert the inactive codeine and therefore in this group it provides no analgesia.

Oral sucrose for infant analgesia

Oral sucrose (25%) has been shown to be a simple, safe and effective means of providing analgesia for young infants (up to 2 months of age) for short painful events (e.g. venepuncture, lumbar puncture).⁵²^–⁵⁴ It stimulates endogenous opioid and non-opioid pathways in the brain. Up to 2 mL may be administered via oral syringe or on a pacifier approximately 2 minutes prior to the painful event.

Parenteral opioid analgesics

Opioid analgesics are the mainstay of treatment of severe pain. Infants and neonates require lower doses of opioid medication. Opioids are ideally administered IV in a dilute solution, e.g. morphine (1 mg mL^–1) given slowly over a few minutes and titrated against response. A further dose may be given after 5–10 minutes. Fentanyl is a potent rapid-acting analgesic with a shorter duration of action and used in combination with midazolam produces a state of dissociation and deep sedation.

Intranasal fentanyl

Intranasal fentanyl provides safe and effective analgesia equivalent to parenteral morphine in children as young as 1 year of age.⁵⁵^–⁵⁸ It offers a quicker onset, is less invasive, and its duration of action, although short, allows time for topical anaesthetic application prior to intravenous cannulation for ongoing analgesia. It is particularly useful for analgesia for fractures or burns dressings but its utilisation is spreading into other areas.

Nitrous oxide

Nitrous oxide mixed with oxygen has a potent analgesic action with rapid onset and offset. It is an excellent analgesic sedative for gaining rapid IV access, injecting local anaesthetics, performing a nerve block or splinting a fractured limb.⁵⁹^–⁶¹

Entonox® (50% nitrous oxide, 50% oxygen) is usually delivered via a demand-valve system. This limits its use in younger or unco-operative children. Machines that deliver variable concentration (30–70%) nitrous oxide via a continuous flow system allow the use of this agent down to age 1 year, where it has been shown to be safe when embedded in a comprehensive sedation programme.⁶¹

Nitrous oxide alone is effective in achieving moderate levels of procedural sedation for a high percentage of children with painful conditions but may require the use of adjunctive analgesics for very painful procedures.^61,⁶²

Oxygen should be administered for 3–5 minutes after cessation of nitrous oxide to prevent diffusion hypoxia. Nitrous oxide is contraindicated in conditions involving closed air spaces (e.g. pneumothorax, bowel obstruction).

Ketamine

Ketamine is a unique analgesic dissociative agent. Its action produces a near ideal state of sedation, amnesia, analgesia and motion control with few side effects. It has been extensively studied, with safety and efficiency documented in several large paediatric studies. It is particularly suitable for laceration repair and orthopaedic procedures in the emergency department. Emergence reactions, common in adults during the recovery phase, are rare in children. Co-administration of midazolam has not been shown to reduce the rate of emergence phenomena but may be associated with less post-procedure emesis. Intravenous ondansetron significantly reduces the incidence of vomiting associated with ketamine sedation.⁶³

Airway complications (including stridor, laryngospasm, respiratory depression, and apnoea) very rarely occur and have been reported as being associated with high intravenous dosing (initial dose >2.5 mg kg⁻¹ or total dose ≥5.0 mg kg⁻¹), administration to children younger than 2 years or aged 13 years or older, and the use of co-administered anticholinergics or benzodiazepines.⁴⁵ There are few data on EDPS in relation to infants under the age of 3 months and the traditional contraindication to ketamine in this age group should continue until there is evidence of safety in this group.

Multiple routes of administration are available but IV and IM routes are preferred.

Both routes display similar risk of airway and respiratory adverse events, and of clinically important recovery agitation. The IM route is associated with a higher rate of vomiting.^45,⁴⁸

Comprehensive ketamine clinical practice guidelines were published in 2004.^64,⁶⁵

Methoxyflurane

A recent review has shown that the inhalational agent Methoxyflurane, long used by ambulance services, is also safe and effective in the ED setting.⁶⁶ The commonly-used ‘Penthrox’ inhaler is now available with an activated charcoal scavenging chamber to reduce environmental contamination.

Propofol

Propofol is an excellent ultra-short acting sedative/hypnotic agent, very useful for EDPS. It provides deep sedation and has anti-emetic and euphoric properties. Propofol has no analgesic properties and therefore needs adjunctive analgesic agents, e.g. fentanyl or ketamine when used for procedural analgesia and sedation (PSA) for short painful procedures. Used alone, it is effective in producing co-operation for painless diagnostic studies in emergency department patients. When combined with opiate agents, it has been used effectively for painful procedures in children (e.g. fracture reduction). It is associated with a significantly higher rate of adverse airway events (oxygen desaturation and need for airway repositioning) when compared to ketamine,⁶⁷ emphasising the importance of having skilled and experienced practitioners available when it is being used.

It does offer quick recovery to pre-sedation state, allowing more rapid discharge. It may be delivered in a variety of manners from repeated boluses to continuous infusion. Despite initial barriers to the use of propofol in the ED, a large number of studies have produced evidence that propofol can be given in a safe and effective manner in ED for children.⁶⁸^–⁷² Titrating and optimising the dose will enhance control of depth of sedation and recovery time.⁷³ Predictable cardiovascular and respiratory events respond to repositioning the airway, increasing oxygen delivery or limited BVM-assisted ventilation without adverse sequelae.⁷³ Capnography is now considered essential for early detection of hypopnoea and apnoea.³¹

An evidence-based Clinical Practice Advisory describing propofol use in EDPS was published in 2007.⁷⁴

Ketafol

Ketafol refers to a mixture of ketamine/propofol in a 1:1 ratio (i.e. 1 mg ketamine: 1 mg propofol). A median dose of 0.75 mg kg⁻¹ of each drug (range 0.2–2.0) has been shown to be safe and effective for procedural sedation in children.⁷⁵ Fentanyl is usually used as adjunctive analgesia but a study looking at combining propfol with a sub-dissociative dose of ketamine (0.3 mg kg⁻¹ IV) compared with fentanyl suggested that the ketamine/propofol combination was safer.⁷⁶ Further research is required to determine if combining the two agents together is associated with fewer cardiovascular and respiratory adverse effects than using propofol alone.⁷⁷

Local and topical anaesthetic agents

The expanded use of topical anaesthetics has revolutionised the management of simple lacerations in the ED and has also greatly improved conditions for intravenous cannulation and lumbar puncture. These agents provide a non-invasive means of producing local anaesthesia and can be applied at triage to facilitate timely management in the ED.⁷⁸

EMLA® (2.5% lidocaine, 2.5% prilocaine) is a well-established topical anaesthetic for use on intact skin prior to venepuncture, intravenous cannulation or lumbar puncture. Its use in the ED is, however, limited, due to its long onset to peak effect (at least one hour) and its vasoconstrictive effect, which may make cannulation more difficult. EMLA® has a theoretical risk of methaemoglobinaemia and is not recommended in infants less than 3 months of age.⁷⁹

Amethocaine (e.g. AnGel® – 4% amethocaine) has a quicker onset of action (30–45 minutes) than EMLA® and its vasodilating effect may facilitate cannulation. Tetracaine is superior to EMLA® in terms of lessening pain associated with intravenous cannulation and is more effective than EMLA® when application time is less than 60 minutes.⁸⁰

Itching and erythema are side effects of tetracaine, whilst skin blanching is seen with EMLA® as a consequence of vasoconstriction.⁸⁰

Topical wound anaesthetics, e.g. Laceraine® (adrenaline [epinephrine] 1:1000, lidocaine 4%, tetracaine 0.5%) and Adrenaline Cocaine Gel (adrenaline 1:1000, cocaine 12%) permit wound management with minimal to no discomfort.^81,⁸²

Cocaine-containing topical wound anaesthetics (e.g. TAC – tetracaine, adrenaline, cocaine) were originally found to be very effective in providing good wound anaesthesia but non-cocaine-containing topical wound anaesthetics have now been shown to be equivalent or superior to cocaine-containing preparations, Such preparations are significantly cheaper, are not associated with the requirement for secure storage and avoid the potentially serious systemic side effects that have been reported with cocaine-containing preparations.⁸³^–⁸⁵

There are no commercially available cocaine-based wound anaesthetics available in Australia currently.

Local anaesthetic combination solutions such as Laceraine® instilled in a wound for 20–30 minutes provide sufficient anaesthesia for suturing 75–90% of scalp and facial lacerations ^82,⁸⁶ and 40–60% of extremity wounds. Its vasoconstrictive effect is also useful prior to application of cyanoacrylate tissue adhesive.

Wound infiltration with injectable local anaesthetics can be carried out with lessened pain by buffering the local anaesthetic, warming the solution to body temperature, using fine-bore needles and slow administration techniques through the wound edges rather than through intact skin.⁸⁷^–⁹¹ Nitrous oxide and distraction techniques during the process of injection often provide good analgesia. Safe dosage regimes must be adhered to by the clinician.

Regional anaesthetic techniques

Regional nerve blocks may be used for either pain relief (e.g. femoral nerve block for femur fracture) or to facilitate suturing, fracture or dislocation reduction (e.g. digital or metacarpal blocks).^79,⁹² Nerve blocks have traditionally been performed using anatomical landmarks, with variable results. The use of ultrasound has been shown to increase the success of regional anaesthetic techniques. Intravenous regional anaesthesia (Bier’s block) is useful and effective for some older children. Tired children, reluctant children, parental concern, or the lack of ED resources may make deep sedation or a general anaesthetic the preferred approach.

Discharge analgesia

Lack of appropriate or inadequate dosing of discharge analgesia is an ongoing problem. Pain experienced at home post acute injury or PSA in the ED can place considerable extra burden on family physicians for pain- related issues. It is essential to include adequate discharge analgesia in ED pain management guidelines. Ibuprofen was found to be preferable to paracetamol and codeine for outpatient management for children with uncomplicated arm fractures.⁹³

Selection of agents by procedure and age

Pain management can be simplified by dividing pain into mild, moderate and severe categories and matching this with the appropriate analgesic agent(s) (Table 20.1.11). It is best to minimise the number of agents used and to be familiar with doses, duration of action, adverse effects and contraindications. Choice of agent should be individualised for the child’s level of pain and the procedure. Dissociative techniques using various combinations of agents are useful for very painful procedures or in infants and toddlers.