Pre-hospital analgesia: Part 1

Cite this article as:
Joe Mooney + Dani Hall. Pre-hospital analgesia: Part 1, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.26121

You’re on a shift in the Rapid Response Vehicle. The radio crackles to life; a two-year-old has pulled a chest of drawers onto himself. He’s conscious and breathing but his leg is badly injured. Lights and sirens on, you wonder what is going to greet you.

The prehospital challenge

Assessing children in the prehospital environment can be challenging. As a stranger arriving at a child’s house at a time when they’re feeling unwell, hurt, or scared, we can seem frightening. Attending multi-patient scenarios, such as a road traffic collision, where both child and parent are injured poses additional challenges. Separating a child from their parent to attend different adult and paediatric hospitals can be hugely traumatic for the child (and the carer )and although we try to get another adult to the scene to accompany the child to the hospital, this isn’t always possible.

In the prehospital setting, we don’t have the luxury of time. A quick decision needs to be made: is this child sick or not sick?

For many prehospital clinicians, children make up a very small proportion of their workload. Drawing up paediatric-drug doses and administering these medications to a scared child takes training and practice.

All of this can make a clinical assessment of a child difficult. Taking off the high-vis jacket, getting down to the child’s level, making a glove-balloon character and using bubbles can all help a child feel at ease.

The prehospital assessment toolbox

There are some validated tools in our box to help overcome these challenges. The Paediatric Assessment Triangle has been used by prehospital care providers at all levels for many years, allowing clinicians to form a hands-off, quick impression about whether the child is sick or not sick.

The triangle is made up of 3 elements: A, B, and C, a mnemonic familiar to clinicians around the world. But this ABC does not stand for airway, breathing, and circulation but instead translates to Appearance, work of Breathing and Circulation to the skin.

Appearance… Is the child interacting with caregivers and ambulance crew? Are they lethargic? Crying? Consolable? Limp in caregivers arms?

Work of Breathing… Are they using accessory muscles to help move air? Are they tripoding? Nasal Flaring? Are they breathing fast or slow? Can you hear a wheeze or stridor?

Circulation to the skin… Are they pale? Cyanotic? Mottled?

If all three parts of the triangle are normal the child is likely to be stable. If all three parts of the triangle are abnormal the patient is in cardio-respiratory failure.

Assessment of pain in the prehospital environment also poses different challenges to the assessment in the hospital, for the same reasons. We use the same age-appropriate pain scales as our hospital-based colleagues: FLACC, Wong-Baker and analog pain scale. Clinical practice analgesia guidelines help direct medication choice, from simple painkillers such as paracetamol and ibuprofen, to stronger analgesics like opiates and ketamine.

The ideal analgesic

The ideal properties of an analgesic are to provide effective pain relief rapidly, with painless administration. Gaining intravenous access in children can be challenging in the field, traumatic for children, and can delay administration of analgesics. It really can’t be stressed enough how important it is not to traumatise a child with cannulation when a good alternative is available. Intranasal fentanyl has had a huge impact on paediatric pain relief prehospitally. In the UK, diamorphine is sometimes used instead of fentanyl; both are potent intranasal opioids that are rapidly and efficiently absorbed from the nasal cavity, giving significant potential for pain management in children.

Arriving at the house, you can hear a child crying; he’s maintaining his airway and is conscious. You make a snapshot PAT assessment: he’s stable. But his thigh is swollen and it’s clear he’s fractured his femur. His parents have given him paracetamol and ibuprofen. This one’s beyond the call of bubbles, so you put them away and instead draw up 0.02mg of fentanyl and give it intranasally.

The intranasal route

Analgesia can be given orally, rectally, intravenously, intramuscularly, or intranasally. Oral medications are metabolized via the hepatic first-pass pathway, meaning they are absorbed from the gastrointestinal tract and delivered first to the liver by the portal vein before reaching the systemic circulation, resulting in a relatively slow onset of action. Intranasal medications, on the other hand, are absorbed directly into the systemic circulation, completely bypassing hepatic first-pass metabolism, so their bioavailability is higher and their onset of action is much faster. And because the nasal mucosa is highly vascularized, with more blood per cubic centimetre than muscle, brain or liver, with a surface area that’s massively increased by the three turbinates in each nostril (out pouches of bone inside the nostrils that create passageways that to warm and moisten the air that flows in through the nose), it is an ideal surface through which drugs with small molecular weights like fentanyl can be absorbed.

Once absorbed into the nasal blood vessels, drugs drain to the right side of the heart via the superior vena cava, are pumped into the pulmonary circulations, and then back through the left side of the heart to the systemic circulations.

Some intranasal drugs have an even faster mechanism of action. It’s thought that fentanyl, and other drugs with very small particle sizes, can also transfer directly to the brain, via the olfactory and trigeminal nerves. This nerve superhighway means they can bypass the blood-brain barrier, and work even faster at their central receptors in the brain.

The intranasal analgesic cavalry

Fentanyl is a synthetic opioid; diamorphine is a morphine derivative. As fentanyl doesn’t cause histamine release, it results in less cardiorespiratory side effects than other opiates. Both fentanyl and diamorphine can be safely combined with oral morphine, meaning intravenous morphine top-ups are less likely to be required. When they’re given intranasally, their onset is within two to three minutes, with effects lasting up to half an hour. It’s easy to see how they’ve become a perfect choice for prehospital providers.

Ketamine, another analgesic in the prehospital analgesic armory, can also be given intranasally, although is not yet licensed via the intranasal route in children in the UK and Ireland. A few trials have compared intranasal ketamine and fentanyl and there have been some interesting results, posing the question as to whether sub-sedative doses of intranasal ketamine could be used as an alternative analgesic for children with limb trauma.

Published in Annals of Emergency Medicine in 2014, the double-blinded RCT, PICHFORK (Pain In Children Fentanyl OR Ketamine), was run in two large Australian paediatric EDs.  Children aged 3 to 13 years old with moderate to severe pain secondary to an isolated limb fracture were randomized in a double-blinded fashion to receive either 1.5 μg/kg intranasal fentanyl or 1mg/kg intranasal ketamine. 73 children were included in the analyses. Similar reductions in pain scores were seen at 30 and 60 minutes for both drugs. The ketamine group had higher patient satisfaction scores (83% compared to 72% for fentanyl) but more minor adverse events (78% compared to 40% of the fentanyl group). Published in 2017, a similar double-blinded RCT conducted in a level II trauma centre in America compared the two intranasal drugs at the same doses in 82 children aged 4 to 17. Like PICHFORK, their results showed more side effects in the intranasal ketamine group (2.2 times higher), but all were minor, with no respiratory adverse events. Analgesic effects at 20 minutes were similar in both groups. And finally, the PRIME (Pain Reduction With Intranasal Medications for Extremity Injuries) trial, a double-blinded RCT published in JAMA Pediatrics in 2019, showed similar results. 90 children, aged 8 to 17 years, presenting to a level I major trauma centre with limb trauma were randomized to receive either intranasal ketamine or fentanyl. Doses used were higher than those in standard clinical practice guidelines, with intranasal fentanyl dosed at 2μg/kg and intranasal ketamine at 1.5mg/kg. Like the other two trials, pain scores at 30 minutes were similar between both groups, while mild adverse events were found to higher in the ketamine group (with a relative risk of 2.5), although again all were transient.

So, is there a role for intranasal ketamine for children with isolated limb fractures in the prehospital or ED setting? None of these studies were powered to show a superiority of intranasal ketamine over fentanyl, but they do suggest that it’s non-inferior and a potential alternative. Although minor and transient, adverse events were higher in the ketamine groups, so it may not trump fentanyl as a first choice analgesic. But for children in whom an opiate is contraindicated, intranasal ketamine might be an alternative. More data will be needed before intranasal ketamine makes its way onto standard CPGs, but results from these trials are promising, with larger studies on the horizon.

After the intranasal fentanyl, the child settles. You apply traction to his leg, and with your colleagues’ help, you move him into an adult lower limb vacuum splint. This is a handy trick you’ve learned – the leg splint is just the right size to use as a whole body splint in small children, maintaining pelvic and spinal precautions. After moving to the back of the ambulance, he starts crying and is obviously in pain. You give him a second dose of 0.02mg fentanyl and phone medical support and discuss options with a senior clinician and get the go-ahead to give the third dose, en route to the hospital, if needed.

Ambulance control pre-alert the emergency department so they can prepare for an incoming paediatric trauma. The child’s mother sits next to the stretcher, holding his hand while you travel to the hospital. You explain to her what’s happened so far, what will you do if anything changes, and what might happen in the hospital. This calms her down. The child sleeps and that third dose of intranasal fentanyl is not required. As you pull onto the ambulance ramp he wakes. You hand him over to the waiting trauma team in resus; intravenous access is gained, IV morphine is given, and a Thomas Splint applied. After his primary survey is completed, an x-ray is taken, which confirms a femoral fracture.

The prehospital cannula

The question about intravenous access in the field is a tricky one. Inserting an IV line in a 2-year-old, particularly in the back of an ambulance, can be extremely difficult, and securing a cannula while travelling at speed requires the dexterity of a magician. If intranasal medication is working then there may not be the need for an IV line prehospitally. This always has to be balanced with the potential need for fluid resuscitation, or other intravenous drugs. Each case is a judgment call, based on the paediatric assessment triangle assessment and need for intravenous medications. But never forget, if a child’s in pain and the bubbles don’t work, don’t forget the fentanyl.

Selected reference

Reagan L, Chapman AR, Celnik A, et al. Nose and vein, speed and pain: comparing the use of intranasal diamorphine and intravenous morphine in a Scottish paediatric emergency department. Emerg Med J 2013; 30:49–52.

Graudins A, Meek R, Egerton-Warburton D, Oakley E, Seith R. The PICHFORK (Pain in Children Fentanyl or Ketamine) Trial: A Randomized Controlled Trial Comparing Intranasal Ketamine and Fentanyl for the Relief of Moderate to Severe Pain in Children With Limb Injuries. Ann Emerg Med [Internet]. 2015 Mar 1 [cited 2019 Jun 20];65(3):248-254.e1. Available from: https://www.sciencedirect.com/science/article/pii/S0196064414013638

Watts P, Smith A, Perelman M. Nasal delivery of fentanyl. Drug Deliv Transl Res [Internet]. 2013 Feb 1 [cited 2020 Jun 8];3(1):75–83. Available from: https://doi.org/10.1007/s13346-012-0078-y

Goldman RD. Intranasal drug delivery for children with acute illness. Curr Drug Ther 2006; 1:127–130.

Hadley G, Maconochie I, Jackson A. A survey of intranasal medication use in the paediatric emergency setting in England and Wales. Emerg Med J 2010; 27:553–554.

Mudd S. Intranasal fentanyl for pain management in children: a systematic review of the literature. J Pediatr Health Care 2011; 25:316–322

Finn M, Harris D. Intranasal fentanyl for analgesia in the paediatric emergency department. Emerg Med J 2010; 27:300–301.

Telfer P, Criddle J, Sandell J, et al. Intranasal diamorphine for acute sickle cell pain. Arch Dis Child 2009; 94:979–980

Prepare for transport: Costas Kanaris at DFTB19

Cite this article as:
Team DFTB. Prepare for transport: Costas Kanaris at DFTB19, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.22605

Costas Kanaris is a paediatric intensivist working in Manchester. He is also internet-famous for his challenging #fridayquiz in which he presents a case, drip-feeding information, as the Twitter audience figure out the diagnosis and the best way to treat the patient in front of them.

This time he tries it in front of a live studio audience. Here is a teaser to tickle your brain.

 

This talk was recorded live at DFTB19 in London, England. With the theme of  “The Journey” we wanted to consider the journeys our patients and their families go on, both metaphorical and literal.

If you want our podcasts delivered straight to your listening device then subscribe to our iTunes feed or check out the RSS feed. If you are more a fan of the visual medium then subscribe to our YouTube channel. Please embrace the spirit of FOAMed and spread the word.

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Procedural sedation

Cite this article as:
Tadgh Moriarty. Procedural sedation, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.23718

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 the use of 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 on your PEM shift. You have just seen Kayla, a 20-month-old girl who fell from onto a concrete step and sustained a nasty L-shaped laceration to her thigh. You have satisfied yourself that her joints are not involved, and an x-ray reveals no underlying fracture. You can see a large amount of debris within the wound. Her vaccines are up to date and she has no significant medical history. She is, however, eating a large ice cream cone that her parents had purchased 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 viewed as a substitute for good pain relief. Maximize analgesia and recruit any distraction devices to hand (iPads / parents / play specialists – these are a particularly excellent resource and should be utilized 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 30-60minutes to be fully effective after application so be sure to allow sufficient time. Even if the patient is progressing 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 used for procedural sedation in paediatrics are midazolam, nitrous oxide, and ketamine.

 

Kayla’s LAT gel has been in situ 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 remains upset. You decide PPS is needed to ensure effective irrigation, neat wound closure, and avoiding further trauma to an upset child (and mother!)

 

Which agent is best suited?

You need to consider what you hope to achieve with sedation and what level of experience and resources are available currently in the department to aid in answering 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, co-operative, 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. 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. There’s no way you’re going to get Kayla to cooperate with the nitrous mask. So ketamine is selected as 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, oftentimes with the patient’s eyes open but ‘nobody home‘ (it is important to warn parents beforehand about this as it can be quite scary if unexpected). Some of the many benefits of ketamine are that airway reflexes are maintained, while 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 assessment includes 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 Kayla, 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 the need for conducting a thorough pre-sedation assessment, including assessing ASA grade, all of 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 prior to 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 5 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%). There were 69 (1.1% of cases) serious adverse events (SAE). Ketamine as single-agent had the lowest SAEs at just 0.4%.

Pre-procedural opioids and laceration repair were associated with 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 5 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 these only 0.02% required intubation.

Both of these large studies demonstrate ketamine’s excellent safety profile when used with the appropriate preparation and patient selection.

 

Does Kayla need to have 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 a rare event. Furthermore, they concluded that non-fasted patients were at no greater risk of major 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. They acknowledged that the current evidence does not support the rationale put forth 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 in relation to 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 actually the recommendation back then too. Really 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.

 

Where will Kayla’s procedure be carried out, how many staff do you require, and what equipment should get ready?

 

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 member of staff but really, it’s anyone who is 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. The American Academy of Pediatrics advised the use of capnography as an adjunct in order to detect hypoventilation and apnoea earlier than pulse oximetry or clinical assessment alone. While no evidence currently 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 minimal requirement in their most recent guideline iteration, in parallel with their previously recommended monitoring of respiratory rate, heart rate, oxygen saturations, 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 in that 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 key resuscitation drug dose calculations performed prior to 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’re checking 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.

 

Should any adjunctive agents be used with ketamine?

There was a previous vogue to co-administer a benzodiazepine to reduce the incidence of emergence. A 2018 BestBets review looked at this very question by studying 6 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. In fact, the only difference demonstrated was increased rates of adverse advents when a benzo was co-administered. So, no prophylactic benzodiazepine required.

Having said this, if a child suffers severe emergence (older children, in particular, have 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 routine use of anticholinergic medication such as atropine to prevent laryngospasm or other adverse airway events.” Concurrent anticholinergics may actually 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 the use of 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 prophylaxis in high risk groups: those with previous nausea/vomiting during sedation/anaesthesia, older children, or IM administration. The NNT depending on age of the patient 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 for those receiving preprocedural opioids. As with any drug, however, you’ll need to balance the risk-benefit ratio in your mind. Some would prefer not to use ondansetron prophylactically because of the risk of arrhythmias in children with undiagnosed long 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 ready and is just removing the Ametop from Kayla’s hands which had been applied when PPS was considered; one of the ANPs will be the procedural clinician and your consultant will supervise you as the sedation clinician. You cannulate first go, while Kayla is distracted by Peppa Pig on screen. It’s time to dissociate.

 

But what dose will you give Kayla?

Various opinions exists 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 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 by about 60 to 120 minutes.

Many departments are still using intramuscular (IM) ketamine. This can be particularly helpful in certain situations such as 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 biggest change in their new guidance; the 2016 guideline included dosing and top-up recommendations for IM ketamine.

 

There are still some children who would 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 over to the drug cupboard to collect your syringes with carefully calculated doses, your consultant asks, “Are you confident in managing any potential airway 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 the use of 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 prior to 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, very similar to performing a strong jaw thrust. If there is no response at this point, with critical airway compromise, then 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 of benefit – 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. 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 completed without difficulty and the nurse enquires as to how long Kayla needs to remain monitored for?

 

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

 

Kayla successfully underwent ketamine PPS, allowing a thorough wash out of her wound and suturing which provided a tidy end result. She was later discharged with an antibiotic prescription and a teddy which the play specialist had found in the toy room for her. 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 noticed plenty of bouncy castles and trampolines in use. 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 and 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, usually 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 best to wait for this before commencing the procedure. Once the intervention or procedure is completed it is important to administer 100% oxygen for 3-5minutes post-procedure to avoid diffusion hypoxia. 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 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, methymalonic acidaemia, and homocysinuria (because inactivation of methionine synthase can affect homocysteine metabolism). There’s a theoretical risk to pregnancies in the first trimester and so guidance often suggests avoiding nitrous oxide exposure in early pregnancy.

During administration monitor heart rate, respiratory rate and oxygen saturations. 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’ time. 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 was 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, which is why 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. If used intranasally, a dose of 0.3-0.5mg/kg is suggested. You should notice its onset within 10-15 minutes, lasting about 60 minutes. 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 for 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 oftentimes using basic airway manoeuvres is sufficient. Paradoxical excitatory or agitation reactions can occur in up to 15% of children. Do warn parents of this possibility prior to administration. The best course of action if it does occur 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 basic monitoring includes heart rate, respiratory rate, and oxygen saturation monitoring. At least two staff are required; proceduralist and 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!

 

References

Ketamine Procedural sedation for children in the emergency department. The Royal College of Emergency Medicine. Best Practice Guideline. February 2020.

Bhatt M, Johnson DW, Chan J et al. Risk factors for adverse events in emergency department procedural sedation in children. JAMA paediatrics 2017 Oct 1;171(10):957-964

Bhatt M, Johnson DW, Chan J et al. Risk factors for adverse events in emergency department procedural sedation in children. JAMA paediatrics 2017 Oct 1;171(10):957-964

Green SM, Roback MG, Krauss B, et al. Predictors of airway and respiratory adverse events with ketamine sedation in the emergency department: an individual-patient data meta-analysis of 8,282 children. Ann Emerg Med. 2009; 54(2):158-168.e1-4

Agrawal D, Manzi S, Gupta R, Krauss B. Pre-procedural fasting state and adverse events in children undergoing procedural sedation and analgesia in a paediatric ED. Annals of Emergency Medicine. 2003; 42(5): 636-646

Cravero JP, Blike GT, Beach M, et al. Incidence and nature of adverse events during pediatric sedation/ anesthesia for procedures outside the operating room: report from the Pediatric Sedation Research Consortium. Pediatrics. 2006; 118(3):1087-1096

Beach ML, Cohen DM, Gallagher SM, Cravero JP. Major Adverse Events and Relationship to Nil per Os Status in Pediatric Sedation/Anesthesia Outside the Operating Room: A Report of the Pediatric Sedation Research Consortium. Anesthesiology 2016;124(1):80-8

Godwin SA, Burton JH, Gerardo CJ, et al. Clinical policy: procedural sedation and analgesia in the emergency department. Annals of Emergency Medicine 2014;63(2):247-58.e18

Sherwin TS, Green SM, Khan A, et al.Does adjuctive midazolam reduce recovery agitation after ketamine sedation for pediatric procedures? A randomised, double-blind, placebo-controlled trial. Ann Emerg Med 2000;35:229–38.

Walthen J, Roback M, Mackenzie T et al. Does midazolam alter the clinical effects of intravenous ketamine sedation in Children? A double-blind, randomized, controlled, emergency department trial. Annals of emergency medicine 2000;36(6): 579-587

Green SM, Roback M, Kennedy R et al. Clinical practice guideline for emergency department ketamine dissociative sedation: 2011 update. Annals of emergency medicine 2011; 57(5): 449-461

Dunlop L, Hall D. Antiemetic use in paediatric sedation with ketamine. Emerg Med J 2018; 35:524-525

Krauss B, Green SM. Procedural sedation and analgesia in children. Lancet 2006;367(9512):766-80

Nickson C. Paediatric Procedural sedation with Ketamine. Life in the Fast Lane. March 2019

Zier ZL, Liu M. Safety of high concentration nitrous oxide by nasal mask for pediatric procedural sedation: experience with 7802 cases. Pediatr Emerg Care. 2011 Dec;27(12):1107-12

Gamis AS, Knapp JF, Glenski JA. Nitrous oxide analgesia in a pediatric emergency department. Ann Emerg Med. 1989; 18:177-181

Comfort Kids Programme. Royal Children’s Hospital Melbourne. 2016

Peyton PJ, Wu CY. Nitrous oxide-related postoperative nausea and vomiting depends on duration of exposure. Anesthesiology. 2014;120(5):1137–1145

Baum VC. When nitrous oxide is no laughing matter: nitrous oxide and pediatric anesthesia. Paediatric Anaesthesia 2007;17(9):824-30

Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine. Acute Pain Management: Scientific Evidence.: Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine, 2005

Axelsson G, Ahlborg G, Jr., Bodin L. Shift work, nitrous oxide exposure, and spontaneous abortion among Swedish midwives. Occupational & Environmental Medicine 1996;53(6):374-8

Hoeffe J et al. Intranasal fentanyl and inhaled nitrous oxide for fracture reduction: The FAN observational study. Am J Emerg Med. 2017;35(5):710-715.

Seith RW, Theophilos T, Bable FE. Intranasal fentanyl and high-concentration inhaled nitrous oxide for procedural sedation: a prospective observational pilot study of adverse events and depth of sedation. Acad Emerg Med. 2012;19(1):31-6

Kennedy RM, Porter FL, Miller JP, Jaffe DM. Comparison of fentanyl/midazolam with ketamine/midazolam for pediatric orthopedic emergencies. Pediatrics. 1998;102:956–63

Pena, B.M. and Krauss, B. Adverse events of procedural sedation and analgesia in a pediatric emergency department. Ann Emerg Med. 1999; 34: 483–491

Wright, S.W., Chudnofsky, C.R., Dronen, S.C. et al. Midazolam use in the emergency department. Am J Emerg Med. 1990; 8: 97–100

Davies FC, Waters M. Oral midazolam for conscious sedation of children during minor procedures. J Accid Emerg Med. 1998;15(4):244–248. doi:10.1136/emj.15.4.244

Graff, K.J., Kennedy, R.M., and Jaffe, D.M. Conscious sedation for pediatric orthopaedic emergencies. Pediatric Emerg Care. 1996; 12: 31–35

Bailey, P.L., Pace, N.L., Ashburn, M.A. et al. Frequent hypoxemia and apnea after sedation with midazolam and fentanyl. Anesthesiology. 1990; 73: 826–830

Gregory GA. Pediatric Anesthesia. 4th ed. Philadelphia, PA: Churchill Living- stone; 2002

 

Deb Shellshear: Procedural sedation at DFTB17

Cite this article as:
Team DFTB. Deb Shellshear: Procedural sedation at DFTB17, Don't Forget the Bubbles, 2018. Available at:
https://doi.org/10.31440/DFTB.15031

This talk was recorded live on the second day at DFTB17 in Brisbane. If you missed out in 2017 then why not book your leave for 2018 now. Tickets are on sale for the pre-conference workshops as well as the conference itself at www.dftb18.com.

Ketamine

Cite this article as:
Jess Longmore. Ketamine, Don't Forget the Bubbles, 2016. Available at:
https://doi.org/10.31440/DFTB.10643

You can keep staring at the 3 year old’s deep eyebrow laceration, desperate to glue it, but you know it needs to be sutured. Now what?

Injured or distressed children present us with difficulties in the emergency department. Children experience a more intense physical and emotional reaction to painful or threatening procedures than adults. The goals of sedation of children in the emergency department include minimizing pain, anxiety, movement which may jeopardize the procedure, and maximizing the chances of success for the procedure performed, returning the patient to his or her pre-sedated state as quickly as possible while assuring the patient’s safety. In addition to minimizing the negative psychological experience for the child, sedation will reduce fear and distress in subsequent presentations to health care facilities.

Paediatric procedural sedation has become a domain of expertise in emergency medicine. As emergency physicians, we should be aware of the pros and cons of the different options within paediatric sedation, and not only skilled in the technicalities of each but in the non-clinical aspect of ensuring both the child and the caregiver have as pleasant an experience as possible.

Choice of sedation

There are no hard and fast rules on what sedation to use. One must take into account many variables, including the age (and temperament) of the child, the proposed procedure, fasting time, co-morbidities, and levels of parental anxiety. If a patient or a parent is extremely anxious, or if the procedure has the potential to be very long, complex or painful, it may be more appropriate or kinder for the child to have their procedure done in theatre under general anaesthetic. In a compliant child with a laceration away from the face needing sutures, Nitrous Oxide may be ideal.

Prior to any form of sedation

  • Take time to discuss the options with the parents.
  • Remember to consider systemic pain relief. If using ketamine it is important that the patient is comfortable before the drug is administered – if they are uncomfortable or agitated during administration they are more likely to have nightmares or a scary emergence.
  • ALA (or similar) should be used around wound edges, and AnGel/LMX on potential cannulations sites.
  • Local anaesthetic should be used where appropriate as the analgesic effect will outlast the ketamine.

Ketamine sedation

Ketamine has been described as the “ideal” agent for paediatric sedation, and has rapidly become the drug of choice for short, painful procedures in the ED due to its rapid onset of action, and anxiolytic, analgesic and amnesic properties. Ketamine dissociation results in a lack of response to painful or noxious stimuli, whilst preserving respiratory and cardiovascular stability.

Ketamine use has previously been restricted to anaesthetists, but emergency physicians are using it more and more frequently; ACEM and ACEP both have formal guidelines for emergency physicians especially for ketamine sedations, and most departments will have a local protocol. It should, however, only ever be used in a resuscitation area by an airway trained doctor in case of laryngospasm. It is mandatory to have a separate doctor performing the procedure itself and a nurse credentialed in ketamine sedation. Local policies may specify PLS/APLS certification or similar. This may mean delaying the procedure until daylight hours or calling in the consultant if there is an urgent clinical need.

Absolute contraindication

infants less than 6 months (due to increased risk of airway compromise and recent animal studies which have found that ketamine is involved in neuronal degeneration within the developing brain)

Relative contraindications

  • age less than 12 months
  • high risk of laryngospasm (e.g. asthma, active URTI)
  • significant cardiac disease
  • reduced loc or recent head injury
  • previous psychosis
  • prior adverse reaction to ketamine

Examples of appropriate procedures

  • Suturing
  • Reduction of fractures/dislocations
  • Burn debridement
  • Lumbar Puncture
  • Abscess drainage

For the parents

For successful sedation, it is integral to involve the parents or caregivers and keep them on side. Take the time to explain the procedure to them and gain informed consent. I often given them a leaflet to read about ketamine sedation and then come back ten minutes later to answer any questions they may have. Ensure to go over what will happen, what they will see and what the child will experience.

Examples

  • Your child may seem to be awake after receiving ketamine, their eyes might flicker from side to side or they might twitch – this is normal
  • They may develop a rash
  • They may vomit
  • They may drool
  •  Sometimes as your child wakes up they may be agitated or appear to be having hallucinations or nightmares. These can normally be helped by minimizing sensory input (e.g. talking softly and dimming the lights), but if required we can give a drug that will help to minimize these.
  • In very few cases, we may have to give extra Oxygen or extra drugs
  • Be reassured that your child will not remember the procedure

How parents can help:

Keep calm themselves, reassure the child, talk softly and smoothly and describe a pleasant scene to them as they are given the drug. Remain with the child throughout the procedure and provide positive

Routes of administration

Ketamine can be used intravenously or intra-muscularly, if access is likely to be problem. Studies have concluded that IV ketamine is similar to IM ketamine in terms of efficacy and safety, with no significant difference in the rates of adverse respiratory events, however higher rates of vomiting were found in intramuscular administration.

IM has also been found to last slightly longer, and time to discharge was therefore longer (129 minutes from administration to discharge with intra-muscular ketamine, versus 80 minutes with IV).

Dose

Dissociation can usually be achieved with:

1-1.5mg/kg iv (given over 1-2 mins to avoid apnoea); top up dose of 0.5mg/kg iv can be given if required

4mg/kg im, a repeat dose of 2-4mg/kg can be given after 10 minutes if sedation inadequate

Note – Several studies have shown that higher ketamine doses are required for smaller children

It is normally good practice to site a cannula when the child is dissociated if using the IM route, in case the procedure takes longer or any other drugs are required, and in order to titrate any top-up doses more accurately.

During the procedure

Talk gently and tell the child to choose a dream as they drift off to sleep. You can also describe (or get the parent to describe) a pleasant scene as you are administering the drug.

Adequate sedation is usually indicated by a lack of response to verbal stimuli and nystagmus.Be patient. The effects of ketamine are usually apparent 1-2 minutes after an intravenous dose, and 5 minutes after an intramuscular dose (this can seem a long time with the orthopaedic surgeon staring at you!) Top-up doses can be given as above, but ensure you have waited sufficient time before topping up.

Atropine 0.02mg/kg up to a maximum of 0.6mg can be used to reduce the hypersalivation caused by ketamine which can lead to larynogospasm or aspiration. Recent studies have shown no benefit to routine co-administration of atropine, though prophylactic administration may be considered in procedures in which minimising oral secretions is important, such as lip or tongue wounds. It is worth having it drawn up to be administered in the event of concerns surrounding hypersalivation during the procedure.

Midazolam has previously been used for emergence phenomena, but it should be noted that unpleasant reactions are uncommon and there is no benefit from the routine prophylactic administration of midazolam in children. There is significant variation in the literature with regards to dose, ranging from 0.02mg/kg to 0.1mg/kg. I favour a dose of 0.05mg/kg, but this can be repeated if necessary. I normally don’t draw this up, but have the dose required in my head and the vial nearby should unpleasant reactions arise.

Ondansetron 0.15mg/kg would be the drug of choice for the vomiting child; some clinicians opt to give it prophylactically although there is minimal evidence to support routine use.

After the procedure

Ensure to put the lights down, talk in whispers, and leave the child to wake up

Regular observations are required post procedure until the child is fully awake

Prior to discharge

Ensure the child is fully awake and give them something to eat and drink

Discharge home with parents when able to mobilise and verbalise

Ensure to give appropriate post-procedure advice

References

https://emupdates.com/2011/01/27/taming-the-ketamine-tiger/

https://www.rch.org.au/clinicalguide/guideline_index/Ketamine_use_in_the_emergency_department/

CEM4880-CEC-Guideline-for-Ketamine-sedation-of-children-in-EDs-July-2010-Rev-1.pdf

https://www.rcemlearning.co.uk/references/ketamine-sedation-in-children/

Ketamine dosing in obese adolescents

Cite this article as:
Tessa Davis. Ketamine dosing in obese adolescents, Don't Forget the Bubbles, 2014. Available at:
https://doi.org/10.31440/DFTB.6051

Whilst ketamine is widely used in children of all ages, previous studies (Green et al, 2009) have shown that adverse events associated with ketamine are more common in adolescents (including airway adverse events and vomiting).

Additionally, there is a lack of clarity for calculating the ketamine dose in obese adolescent patients – should it be based on ideal body weight  (Wulfsohn, 1972) or standard mg/kg doses as most guidelines suggest? Standard paediatric guidelines don’t tend to include a max dose – so what are we supposed to do?

This study investigates the dose of ketamine required to achieve adequate sedation in adolescents.

Street MH, Gerard JM, A fixed-dose ketamine protocol for adolescent sedations in a pediatric emergency department, Journal of Pediatrics, 2014

Who was studied?

This was a prospective, observational cohort study.

The study included patients presenting to the Emergency Department aged between 12 and 18 years old and weighing greater than 35kg, who required procedural sedation. They had to meet criteria for ASA Class I or II.

Patients were excluded if they had: craniofacial, airway, and cardiorespiratory abnormalities, previous sedation-related events, neurological masses, or were undergoing an oral procedure.

There were 43 patients – mean age 13.9 years, mean weight 68.8kg, and mean BMI 24.4.

39.5% had a BMI greater than 25.

What was the intervention?

The normal sedation policy was was followed, with pre-oxygenation and ongoing physiological observations. No benzodiazepines or antiemetics were given before sedation.

50mg of IV ketamine was given to each patient (over 30-60 seconds) and then sedation was assessed. Further doses of 25mg IV ketamine were administered until adequate sedation was achieved.

Sedation was measured using the Ramsay Sedation Score (RSS), and ‘adequate sedation’ was when the RSS was 5 or greater.

All patients were managed with the same guidelines. However for data analysis, the patients were split into those with a BMI over 25 and those with a BMI of 25 or less. Data was collected to record the dose of ketamine required to achieve adequate sedation.

What were the measured outcomes?

The main outcome was provider satisfaction with sedation which was based on a 0-100 point scale rating.

Adverse events were noted during the procedure, and families were contacted at 12-24 hours post-procedure to grade their satisfaction and record any other adverse events.

Heights, weights, and BMIs were calculated for all patients.

What did the results show?

81.4% of the cohort achieved adequate sedation after just 50mg of ketamine. All the remaining subjects achieved adequate sedation following a further 25mg dose.

Mean sedation time was 27.4 minutes and mean time to discharge was 116.9 minutes. Time to discharge was shorter in the overweight group.

A similar proportion of people from both the overweight and non overweight groups achieved adequate sedation with the 50mg ketamine dose. Based on actual body weight, the overweight group received less ketamine per kg.

Satisfaction was the same between the groups immediately post-procedure, and also on follow-up. 95.3% of families were satisfied or very satisfied with the sedation.

Were these any ketamine side effects?

  • 2.3% (one patient) had desats which recovered with repositioning
  • 18.6% developed nausea during recovery
  • 14% vomited during recovery
  • 2.3% (one patient) developed agitation which required midazolam

There was no difference in adverse events between the two groups.

No patient required over 75mg of ketamine to achieve initial adequate sedation (but bear in mind that patients did require further doses during the procedure as top-ups). Those in the overweight group required a median dose of 0.79 mg/kg to achieve adequate sedation.

Ketamine dosing in obese adolescents is a poorly understood area. This study indicates that there is no need to give the standard 1-2mg/kg ketamine initially. A fixed dose of 50/75mg should be sufficient to achieve adequate sedation in the obese adolescent population.