Procedural sedation

Sometimes we have to do things that children don’t like. These procedures may be scary, or potentially painful. In this post, we’ll cover a few of the more common techniques.

Case one: Kayla

Earlier this month, the UK Royal College of Emergency Medicine, RCEM, published new guidance on using ketamine for procedural sedation in children in the emergency department, superseding their 2016 guidelines. Follow Kayla through her ED visit as she helps us explore the changes RCEM recommends.

It’s 3 pm on a busy Friday afternoon.

You have just seen Kayla, a 20-month-old girl. She fell from onto a concrete step and sustained a nasty L-shaped laceration to her thigh. There is a large amount of debris in the wound. Her vaccines are up to date and she has no significant medical history.

Unfortunately she is eating a delicious ice cream cone that her parents bought to pacify her.

You wonder how best to proceed as you have a nasty wound that needs thorough irrigation and closure. A toddler is unlikely to tolerate local anaesthetic infiltration as the primary means of anaesthetising the wound.

Does Kayla need procedural sedation?

Paediatric Procedural Sedation (PPS) aims to alleviate the distress around painful procedures but should not be considered a substitute for good pain relief. Maximise analgesia and recruit any distraction devices to hand (iPads / parents/play specialists – these are a particularly excellent resource and should be used wherever possible).

Is the wound suitable for ‘LAT gel’? This revolutionary gel which combines Lignocaine, Adrenaline and Tetracaine, can prevent many sedations when used correctly. It takes 30-60 minutes to be fully effective after application, so allow sufficient time. Even if the patient progresses to procedural sedation, this gel will help with local anaesthesia and analgesia.

The ability to perform PPS will be based on current acuity within the department, available resources, and appropriate staffing skill mix. The three main agents for procedural sedation in paediatrics are midazolam, nitrous oxide, and ketamine.

Kayla’s LAT gel has been on for half an hour. You return to the cubicle armed with a play specialist and nurse, along with your irrigation and suturing materials. Despite a stellar sock puppet show by your play specialist, loud sing-along songs, and Peppa Pig showing on the iPad, your attempt at irrigation is futile; Kayla is still upset.

You decide PPS is needed to ensure effective irrigation, neat wound closure, and to avoid further trauma to an upset child (and mother!)

Which agent is best?

It would be best to consider what you hope to achieve with sedation and what level of experience and resources are available currently in the department to answer this question. The spectrum of use varies from diagnostic imaging through minimally painful procedures (e.g. foreign body removal, vascular access) to painful procedures (e.g. fracture reduction, wound washout and closure). The choice of agent, therefore, will reflect the individual patient (anxiety, cooperative, parental preference) and the staff available at the time.

Kayla requires a short, painful procedure to be carried out, and nitrous oxide or ketamine would be suitable. However, as you start showing her the face mask for nitrous, Kayla freaks out – Kayla had a slightly traumatic experience with a bronchodilator and spacer, her mother explains. You’ll not get Kayla to cooperate with the nitrous mask. So ketamine is the agent of choice.

Just as you are about to begin the pre-procedure assessment one of the student nurses who will be observing the procedure tells you that she has seen a lot on Twitter about the new RCEM ketamine PPS guideline recently but is unclear as to exactly what ketamine is and why it’s useful in paediatrics

Ketamine is an NMDA receptor antagonist. It is a dissociative anaesthetic and potent analgesic and amnesic. Rather than the typical ‘sleep‘ which results after administration of other anaesthetic agents, ketamine induces a trance-like state, often with the patient’s eyes open but ‘nobody home‘ (it is essential to warn parents about this as it can be pretty scary if unexpected). Some of the many benefits of ketamine are that airway reflexes are maintained, while it is augmented heart rate and blood pressure (for the most part – in the compromised circulation, bradycardia and hypotension can occur).

The pre-sedation assessment

You begin Kayla’s pre-sedation assessment.

Your take a focussed history: has Kayla undergone any previous anaesthesia or PPS? If so, did she have any reactions or adverse events? Does she suffer from any chronic medical conditions, take any regular medications or have any drug allergies? Does Kayla have any concurrent medical conditions – especially active asthma, respiratory tract infection or tonsillitis?

You then examine her, ensuring you conduct as cardiorespiratory exam and an assessment of her airway anatomy, including ASA grade. You need to assure yourself that no contraindications exist

RCEM’s 2020 guidance is very specific about conducting a thorough pre-sedation assessment, including assessing ASA grade, which should be thoroughly documented for clinical auditing and safety purposes. An example proforma template is provided at the end of their guideline. This contrasts with the 2016 guideline, which included a list of contraindications, but did not require documentation of ASA grade.

It’s time to consent Kayla and her mum for the procedure. You remember that ketamine is considered safer than other hypnotic drugs such as propofol but need to remind yourself of the specifics and the side-effect profile before consenting.

How safe is ketamine?

Does ketamine have side effects? Yes, but of all sedation agents studied by Bhatt et al. in 2017 (6,760 patients across five sites in Canada), ketamine came out on top. This looked at ketamine/propofol, ketamine/fentanyl, propofol alone and ketamine alone. There were 831 adverse events across all agents (11.7%) – these included oxygen desaturation (5.6%) and vomiting (5.2%). In addition, 69 (1.1% of cases) serious adverse events (SAE) occurred. Ketamine as a single agent had the lowest SAEs at just 0.4%.

Pre-procedural opioids and laceration repair were associated with an increased risk of emesis. Bhatt et al. noted that prophylactic antiemetics reduce the risk of vomiting by half, but these were not needed in those under five years of age due to the low overall risk of emesis.

This endorsed previous data from a large case series by Green et al. (2009) which demonstrated low rates of adverse events with ketamine PPS; most notably, noisy breathing (not requiring any intervention other than airway repositioning) occurred in 1%, laryngospasm in 0.3% and of this only 0.02% required intubation.

These extensive studies demonstrate ketamine’s excellent safety profile when used with the appropriate preparation and patient selection.

Does Kayla need to be fasted?

Let’s have a look at the current guidelines and evidence. Several large studies have looked at this controversial issue: one study in a US PED in 2001/2002, where only 44% of patients met traditional fasting guidelines, demonstrated no statistically nor clinically significant increase in adverse events in the unfasted population.

A series of over 30,000 children undergoing PPS by Cravero et al. (2006) reported only 1 episode of aspiration – and this was in a fasted patient!

In 2016, Beach et al. published a report based on 140,000 procedural sedation events, noting that aspiration was rare. Furthermore, they concluded that non-fasted patients were at no greater risk of significant complications or aspiration than fasted patients.

In 2014 the American College of Emergency Physicians (ACEP) altered their national guidance stating that procedural sedation “should not be delayed for children in the ED who have not been fasted.” This was based on a systematic review including 3,000 sedation events showing that pre-procedural fasting failed to reduce the risk of emesis, aspiration, or other adverse events. However, they acknowledged that the current evidence does not support the rationale in the non-emergency medicine guidelines that adherence to minimum fasting times decreased adverse events in ED procedural sedation.

This is reflected in RCEM’s 2020 guidance, which states that there is no evidence that complications are reduced if the child has fasted. They advised that the fasting state should be considered about the urgency of the procedure, but recent food intake should not be considered as a contraindication to ketamine use.*

*We cheered when we read this in the 2020 guideline. No more fasting – we’ve been saying this for years! But, a quick look back at the 2016 guideline shows that this was the recommendation back then too. Careful scrutiny shows that a single word, “however”, has been removed from the start of the sentence, “traditional anaesthetic practice favours a period of fasting”, altering the tone of the recommendation to a much less dogmatic mandate about nil by mouth status.

Satisfied that the evidence does not suggest any advantage to fasting children before PPS (who, let’s face it, tend to be less cooperative when hungry anyway), you prepare the room, staff, and equipment for the procedure.

How should you prepare for the procedure?

RCEM recommends at least three operators: the proceduralist (the clinician performing the procedure), the sedationist (clinician responsible purely for managing sedation) and a sedation assistant*. They specifically acknowledge that the clinician responsible for the sedation and the patient’s airway should be experienced in the use of ketamine, and capable of managing its complications. The 2020 guideline has elaborated further on this, coming with a recommendation for a need for suitable training, a minimum of six months’ experience in anaesthesia or intensive care medicine and an up-to-date APLS course.

*RCEM says ‘nurse’ for the third staff member, but really, it’s anyone experienced in monitoring children and supporting the sedationist – doctors can take on this role too.

ACEP’s 2014 position statement concurs with the need for three operators.

The recommendation is that the procedure should be carried out in a resuscitation bay or high dependency area with immediate access to full resuscitation facilities.

Monitoring (every five minutes) of heart rate, blood pressure, respiratory rate, and oxygen saturation is mandated. In addition, the American Academy of Pediatrics advised using capnography as an adjunct to detect hypoventilation and apnoea earlier than pulse oximetry or clinical assessment alone. While no evidence shows capnography reduces the incidence of serious adverse events, available studies show a decreased incidence of hypoxia and respiratory events.

The use of capnography during sedation has been affirmed by RCEM, who have made it a mandatory minimum requirement in their most recent guideline iteration, in parallel with their previously recommended monitoring of respiratory rate, heart rate, oxygen saturation, ECG and BP.

The 2020 RCEM guideline also includes ‘degree of dissociative sedation’ as part of its recommended monitoring during the procedure, which is a new addition to their guidance. Ketamine is unique because it does not conform to the ‘sedation continuum’ – the patient is either dissociated or not. This recommendation is perhaps aimed at prompting the sedation clinician and nursing colleague as to whether dissociation has occurred and as to whether a top-up dose is required (more on that later).

The updated RCEM document specifically advises having critical resuscitation drug dose calculations performed before the procedure and ready access to these, another new addition to their guidance, although no specific drugs are recommended.

Some doses you may find useful are:

As you check the ketamine and emergency drug doses with your nursing colleague, she asks whether you want her to draw up atropine and midazolam.

She is a recent addition to the ED team and mentions that when she worked in theatre some years ago, they frequently gave these medications together with ketamine.

Do you need any adjunctive agents with ketamine?

There was a previous vogue to co-administer a benzodiazepine to reduce the incidence of emergence. A 2018 BestBets review examined this question by studying six relevant studies (including 2 RCTs: Sherwin et al. 2000 and Walthen et al. 2000). These failed to demonstrate a significant difference in emergence between ketamine alone and ketamine with midazolam. The only difference shown was increased rates of adverse advents when a benzo was co-administered. So, no prophylactic benzodiazepine is required.

Having said this, if a child suffers severe emergence (older children, in particular, have an increased risk of recovery agitation), then it is worth considering midazolam (aliquots of IV 0.05-0.1mg/kg) to treat (but not routinely or for minor/moderate emergence).

Another previous trend involved the co-administration of atropine to reduce the risk of aspiration. But the evidence does not support this practice; Green et al. concluded, “There is no evidence to support the routine use of anticholinergic medication such as atropine to prevent laryngospasm or other adverse airway events.” Concurrent anticholinergics may increase the rate of airway and respiratory adverse events. There is a small increased risk of laryngospasm with oropharyngeal manipulation (including suctioning), so atropine (20 micrograms/kg IV) may be considered as rescue therapy if PPS is being used for intraoral laceration repair (although RCEM would recommend not using ketamine for these procedures for this precise reason).

A common side-effect of ketamine is vomiting. RCEM’s 2020 guidance recommends IV ondansetron at 0.1mg/kg (max dose 4mg) to treat intractable vomiting.

Given ketamine’s emetogenic properties, is it worth giving an antiemetic prophylactically? It is worth considering ondansetron (0.1mg/kg IV) as prevention in high-risk groups: those with previous nausea/vomiting during sedation/anaesthesia, older children, or IM administration. The NNT depending on the patient’s age, will lie between Var7 and 9. This was further endorsed by a BestBets review published in the EMJ in 2018, which concluded that ondansetron should be considered when using ketamine for PPS, especially in older children or those receiving preprocedural opioids. As with any drug, however, you’ll need to balance the risk-benefit ratio in your mind. For example, some would prefer not to use ondansetron prophylactically because of the risk of arrhythmias in children with undiagnosed prolonged QT. But, again, long QT is rare…

A resus bay is prepped.

Kayla and her mother are ready.

Roles have been allocated; your nursing colleague is prepared and is just removing the Ametop from Kayla’s hands; one of the ANPs will be the procedural clinician, and your consultant will supervise you as the sedation clinician.

You cannulate the first go while Kayla is distracted by Peppa Pig on screen.

It’s time to dissociate.

But what dose of ketamine will you use?

Various opinions exist regarding the exact or perfect dose; the most commonly accepted dosing schedule is 1-1.5mg/kg for intravenous (IV) administration.

RCEM’s guideline recommends a starting dose of 1mg/kg over 60 seconds (to reduce adverse events such as laryngospasm). This can be supplemented with top-up doses of 0.5mg/kg. This has not changed from their previous guidance.

You should notice the onset of action within a minute. It is easy to spot as the child will develop horizontal nystagmus coupled with a loss of response to verbal stimuli. The heart rate, blood pressure and respiration rate may all increase slightly. Sedation will start to wear off after 20 minutes, with full recovery should occur in about 60 to 120 minutes.

Many departments are still using intramuscular (IM) ketamine. This can be particularly helpful in situations where IV access is difficult.

Due to its variable onset and offset time, longer time to recovery and increased risk of emesis, however, RCEM have now advised against IM except where senior decision-makers deem it necessary. The advice is that “clinicians should be mindful of the perceived safety benefits of having intravenous access from the start of the procedure to mitigate a rare adverse event.” This is the most significant change in their new guidance; the 2016 guideline included dosing and top-up recommendations for IM ketamine.

Some children may still benefit from IM ketamine, so if choosing the IM option, consider a dose of 2-4mg/kg with senior clinical support. Ideally, IV access could be achieved once the child is dissociated, and the IV top-up dose can be administered if required. However, if IV access is impossible or not obtained, the IM top-up dose is 1-2mg/kg. You can expect a slightly slower onset at about 3-5 minutes, with its duration extended from 15-30minutes. Recovery is variable, occurring anywhere between 60-120 minutes.

As you walk to the drug cupboard to collect your syringes with carefully calculated doses, your consultant asks, “Are you confident in managing any potential complications?”

Airway complications with ketamine PPS

Thankfully complications with ketamine are rare. Most events, such as noisy breathing or stridor and minor desaturation, will respond to simple airway manoeuvres to ensure the airway is open, plus high-flow oxygen via a mask with a reservoir bag. The most feared complication, laryngospasm, is extremely rare and most often will respond to simple airway manoeuvres. But sedationists must be competent in managing this before administering the first dose of ketamine.

If laryngospasm is suspected, stop the procedure and call for help. Ensure 100% oxygen is administered if not already in situ. Gently suction any visible secretions. If this fails to improve the situation, begin manual ventilation with ventilation via a bag-valve mask or, if you are comfortable using an anaesthetic circuit, apply PEEP. Some guidelines (and anaesthetists) suggest applying pressure to Larson’s point, similar to performing a strong jaw thrust. If there is no response, with critical airway compromise, RSI is required. Administer the pre-calculated dose of paralytic and intubate. Remember, Green’s reported incidence of intubation secondary to laryngospasm was only 0.02%.

The flowchart below may be helpful – it formed part of my quality improvement project on PPS and was used as a wall chart in the sedation cubicle and included in each sedation proforma booklet. In addition, when emergencies occur, being able to cognitively offload by following step-by-step aide memoires and having pre-calculated doses to hand can be immensely comforting and helpful.

Kayla’s procedure is over without difficulty, and the nurse asks how long Kayla needs to remain monitored?

Children should remain monitored until their conscious state, verbalization, and ambulation are back at pre-sedation levels. They should be able to tolerate oral fluids. Before discharge, a final set of observations should be within normal limits for their age. Consider the need for a prescription (antibiotics or analgesia) before discharge.

Kayla successfully underwent ketamine PPS, allowing a thorough washout of her wound and suturing, which provided a tidy result. She was later discharged with an antibiotic prescription and a teddy which the play specialist had found in the toy room. Delighted with your chance to use “Special K”, you quickly took out your phone to tweet about the latest changes in RCEM guidance in ketamine for procedural sedation in children in the ED (along with the endless uses of ketamine!)

The new RCEM guidance has come at an interesting time – how might it change our practice in PPS in the ED? PERUKI are soon to launch a two-level paediatric procedural sedation survey (name PoPSiCLE – we all know that a good study needs a catchy name) to inform the current status and variations in the practice of PPS in PERUKI, to provide baseline information for developing a network-wide training resource and patient registry. Watch this space…

Case two: Ronan

It’s a sunny Saturday afternoon. The smell of BBQ and summer is wafting through some open windows in the department. On your way to work, you notice plenty of bouncy castles and trampolines in use. So it’s not surprising your first patient is an 8-year-old boy who has fallen awkwardly while trying to impress some other kids at his birthday party.

After examining him and his xray you see he has a midshaft radius and ulnar fracture with some angulation. Thankfully his DRUJ (distal radio-ulnar joint) appears intact, and his radial head is in joint. He needs manipulation of the fractures and application of a backslab.

He’s in a lot of pain, despite the paracetamol and ibuprofen he had at triage. He tells you his favourite birthday cake is at home waiting for him and he wants to get home to blow out all the candles.

You wonder if you can avoid him a trip to the operating room for a general anaesthetic. Would PPS perhaps be a safe alternative?

Nitrous oxide provides anaesthesia, anxiolysis, and also some mild amnesia. However, it offers limited analgesia, so co-administration of an analgesic is recommended. Several key papers, including the FAN study (2017) and Seith et al. (2012), have demonstrated the safety and efficacy of co-administrating intranasal fentanyl (INF) with nitrous oxide.

Once you’re ready to go, move the child into the dedicated resus bay or sedation room. If using piped nitrous oxide with a variable concentration flow meter (ensuring the scavenging system is switched on) titrate the dose from 30-70% according to clinical response. The alternative is Entonox (a 50/50 mix of nitrous and oxygen) which usually comes in portable canisters but requires the child to be able to take a deep breath to overcome a demand valve circuit, generally tricky for the under-fives. You should notice the onset of effect in 30-60 seconds, but its peak effect will be 2-5 minutes, so it’s best to wait for this before commencing the procedure. Once the intervention or procedure is completed, it is essential to administer 100% oxygen for 3-5 minutes post-procedure to avoid diffusion hypoxia. Again, the offset of effects should occur within 2-5 minutes.

Does nitrous oxide have any side effects? While well tolerated by most children, transient minor side effects such as nausea, dizziness, and occasionally nightmares can occur. It can cause vomiting in 6-10% of children receiving a 50% nitrous dose. This rate increases with higher concentration and can increase up to 25% if an opioid is co-administered. Be sure to warn parents about this relative frequency of vomiting when using nitrous oxide, both during and after sedation. The risk of vomiting also increases with a longer duration of nitrous administration. Consider a prophylactic antiemetic if the child has a history of nausea or vomiting.

Nitrous oxide diffuses through tissues more rapidly than nitrogen alone and can expand in air-containing spaces within the body. This makes it contraindicated for use in patients with gastrointestinal obstruction, pneumocephalus, pneumothorax and after diving.

Nitrous oxide inactivates the vitamin B12-dependent enzyme, methionine synthase, and so can deplete vitamin B12 stores. Because of this, caution is advised in those at risk of vitamin B12 deficiency such as vegetarians, patients with gastrointestinal disorders and those taking regular H2 receptor blockers and proton pump inhibitors. Nitrous should also be avoided in those with metabolic diseases, especially methionine synthase deficiency, methylmalonic acidaemia, and homocystinuria (because the inactivation of methionine synthase can affect homocysteine metabolism). There’s a theoretical risk to pregnancies in the first trimester, so guidance often suggests avoiding nitrous oxide exposure in early pregnancy.

During administration, monitor heart rate, respiratory rate and oxygen saturation. At least two staff members are required; a sedationist and a proceduralist.

Ronan and his mum are happy for you to use nitrous oxide and eagerly his mum signs the consent form.

While setting up the sedation room and recruiting a nursing colleague to assist, you administer intranasal fentanyl. Ronan successfully undergoes manipulation of his fractures, and an above elbow backslab is applied.

His post-reduction x-ray shows you performed a pretty awesome reduction, and, in consultation with your orthopaedic colleagues, you are happy for Ronan to be discharged to return to their fracture clinic in a few days. This delights Ronan, as he gets to return home to his birthday party (with strict instructions to remain off the trampoline), and he promises to bring you back some of his birthday cake later!

Case three: Chantelle

Your junior colleague has come to you for advice. She has just seen a 4-year-old girl who had been hard at work in her playroom creating unicorn pictures. Her mum had given her lots of colourful supplies including some glittery sequins and beads.

Chantelle became adventurous and decided to decorate herself rather than the unicorns. Unfortunately, one of the beads has become lodged in her ear and despite an attempt by your colleague using both parents, and a play specialist, the removal of the foreign body was unsuccessful.

You believe the use of PPS will be required and begin pondering which agent to use.

Midazolam is a hypnotic agent providing anxiolysis and amnesia. It does not have analgesic properties, so it is important to co-administer with analgesia for any painful procedure. It can be administered by many routes, the two commonest for PPS being intranasal (IN) and orally. A dose of 0.3-0.5mg/kg is suggested intranasally. You should notice its onset within 10-15 minutes, lasting about 60 minutes. However, this route of administration can cause some nasal irritation and burning, so some clinicians prefer to use it orally. With an oral dose of 0.5mg/kg, you should notice onset at 15-30 minutes with a duration of effect of 60-90 minutes. Midazolam tastes bitter – so give it with some juice or squash to make it more palatable. Midazolam can be given intramuscularly (IM) and intravenously (IV), but it is less likely to be used in this fashion for PPS.

Does midazolam have any side effects? Yes! It can cause hypoventilation and apnoea – be aware that this risk is increased if co-administered with an opioid such as fentanyl or diamorphine. A reversal agent does exist: flumazenil (0.01mg/kg, max dose 1mg), but this is rarely required, and using basic airway manoeuvres is often sufficient. Paradoxical excitatory or agitation reactions can occur in up to 15% of children. Do warn parents of this possibility before administration. If it does happen, the best action is to let the child “ride it out”. Because of this, many ED clinicians will choose ketamine or nitrous oxide as their PPS agent of choice over midazolam.

With these side effects in mind, it is prudent to ensure essential monitoring including heart rate, respiratory rate, and oxygen saturation monitoring. At least two staff are required; a proceduralist and a sedationist.

Having obtained informed consent from Chantelle’s mother, you decide to give her intranasal midazolam. 45 minutes later you remove the mischievous bead from her left ear.

Her parents are thrilled, but before you leave the room you remember the mantra of “always check the other ear”.

So before packing up your tools and leaving her with your sedation nurse, you decide to check her other ear. Interesting you find two glittery sequins hiding in her right ear canal. Phew, that saved a second sedation event!

Check out the DFTB Procedural sedation course to help you level up.

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