Author Archives: PEMLit

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Reviewing the PEM Literature for your interest and development! #FOAMed @PEMLit

23rd November 2012: Early Lactate Testing in Undifferentiated Paediatric SIRS

Where can I find this paper?

http://www.ncbi.nlm.nih.gov/pubmed/23167859

What is this paper about (what is the research question)?

Does an ED measurement of hyperlactataemia (serum lactate ≥ 4.0mmol/L) predict increased risk of organ dysfunction within 24h?

Summary of the Paper

Design: single-centre prospective observational cohort study

Objective: to ascertain whether an ED serum lactate of ≥4.0mmol/L predicts risk of organ dysfunction within 24h in paediatric patients presenting with systemic inflammatory response syndrome (SIRS)

Intervention: point-of-care venous lactate measurement

Primary outcome: organ dysfunction within 24h of triage time, classified following International Paediatric Sepsis Consensus Conference definitions.

Population: convenience sample of patients presenting to ED of tertiary children’s hospital over 1 year (recruitment occurring 17/24h per day)

  • Inclusion: patients <19 years old with temperature >38.5 or <36 and HR>2 standard deviations above normal for age, undergoing phlebotomy or CVC access as part of their care
  • Exclusion: patients transferred from other institutions, patients with known inborn errors of metabolism, lactate not measured within 15mins of IV therapy initiation.

Results: 239 eligible subjects enrolled (missed eligible rate 36%), of whom 8% were admitted to an intensive care unit.

Mean lactate was 2.0 (+/- 1.2) mmol/L. 8% of subjects had hyperlactataemia. 5% of subjects had organ dysfunction within 24h; 4% of the low lactate population, 22% of the hyperlactataemic population.

Hyperlactataemia had an LR+ of 5.0 (95% CI 1.9-13.0) for organ dysfunction within 24h, sensitivity 31% (95% CI 13-58%), specificity 94% (95% CI 90-96%).

The relative risk of lactate ≥ 4.0mmol/L was 5.5 for 24-hr organ dysfunction

Authors’ Conclusions:

Serum lactate measurement identifies a population at higher risk for severe outcomes than the broader Paediatric ED population with fever and tachycardia and would be a useful addition to clinical assessment in paediatric sepsis clinical and research protocols.

On the study design

As with so many papers, the convenience sampling presents a potential problem in extrapolating this data to our own EDs. While convenience sampling is common, practical and understandable, it does impact the external validity.

To their credit, the authors have been honest about this, giving us a “missed inclusion” rate of 36%. This suggests that greater than 1/3 paediatric patients presenting with two SIRS criteria do so in 29% of the 24h period. We can only imagine how including these patients would affect the results.

The inclusion criteria are interesting too; I would suspect that many more than 239 patients present to an average PED with fever and tachycardia in 12/12 (particularly as we know that the annual attendance is around 80,000). This means that a large number of these patients did NOT have blood tests. This, of course, represents our standard practice (we don’t bleed every child with a temp and tachycardia), but it means we can only really consider the value of lactate measurement in those children whom we already deem to be systemically unwell. It would also be useful to know if a capillary lactate could help to identify those patients for whom we are not sure whether blood tests are necessary.

What were the results and what does this mean?

Despite small numbers, the study was adequately powered by their own calculation. The relative risk of lactate ≥4.0mmol/L for 24-hr organ dysfunction means that patients with an initial lactate above 4.0mmol/L have 5.5 times the risk of 24-hr organ dysfunction as those with a lactate below 4.0mmol/L. They also had 2.2 times the risk of serious bacterial infection, 4.6 times the risk of positive culture and 4.4 times the risk of ICU admission.

The low sensitivity sensitivity (31% (95% CI 13-58%)) tells us that we cannot be reassured by an initial normal lactate (we are unable to use it to “rule out” serious illness), but the specificity is  reasonable at 94% (95% CI 90-96%) – raised lactate should raise our concern. Clinically, a high specificity is more useful to us as arguably it is more important to reliably rule-in serious illness.

What can we take from this paper into clinical practice?

If we are taking bloods in children in the ED because they have signs of SIRS, a venous lactate may help with risk stratification by predicting those more likely to require antibiotics and organ support. It is probably worth taking one if you are taking bloods, but a normal lactate is not reassuring. It is not yet clear how this applies to children about whom we are unsure as to the need for blood tests.

More questions to ask

  • How would the results differ if we obtained a venous (or capillary) lactate from  all paediatric patients meeting the two SIRS criteria used in this paper (temperature and heart rate)?
  • How would results be affected  if we included children recruited around the clock rather than a convenience sample?

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21st November 2012: Accuracy of Point-of-Care US for Diagnosis of Elbow Fractures in Children

**Sincere apologies for the delay in this post (due 16th Nov, delayed by technical problems)**

Where can I find this paper?

http://www.ncbi.nlm.nih.gov/pubmed/23142008

What is this paper about (what is the research question)?

How good is ultrasound at diagnosing elbow fractures in children?

Summary of the Paper

Design: prospective, observational, multi-centre diagnostic study

Objective: to determine the performance characteristics of ED ultrasound by PEM physicians for diagnosis of elbow fractures in children

Test under evaluation: ED (point-of-care) ultrasound of the elbow (scanning protocol pre-determined) to determine presence of lipohaemarthrosis OR elevated posterior fat pad

Reference standard: plain radiographs reported by radiologists blinded to ultrasound findings. Clinical follow-up with notes review or structured telephone follow-up; radiologist report used if follow-up imaging performed.

Primary outcome: determination of test characteristics

Population: convenience sample of patients aged up to 21yrs presenting to either of two urban EDs when a trained study physician was available, between Sept 2010 and Dec 2011.

  • Inclusion: possible elbow fracture requiring radiographic assessment
  • Exclusion: elbow radiographs already obtained, previous confirmed elbow fracture, open wound at the elbow, unstable vital signs, severe life threatening injuries requiring resuscitation.

Results: 130 patients enrolled, fracture present on initial ED radiography in 38/130. 5 additional fractures diagnosed on follow-up radiography (23 patients).

Elevated posterior fat pad was seen on initial XR in 57/130 patients (44%): 36 with fracture, 21 without (of whom, 4 patients had fracture identified on follow-up).

Elevated posterior fat pad OR lipohaemarthrosis was seen on ED US in 68/130 patients.

Elevated posterior fat pad OR lipohaemarthrosis gave the following test characteristics: sensitivity 98% (95% CI 88-100%), specificity 70% (95% CI 60-79%), PPV 0.62 (95% CI 0.50-0.72), NPV 0.98 (95% CI 0.91-1.0), LR+ 3.3 (95% CI 2.4-4.5), LR- 0.03 (95% CI 0.01-0.23)

Authors’ Conclusions:

With focused musculoskeletal ultrasonographic training, novice PEM sonologists were able to attain the skills necessary to perform point-of-care elbow ultrasonography to evaluate for fracture by assessing the posterior fat pad for elevation and lipohaemarthrosis. 

On the study design

Despite including “children” up to the age of 21 (!), there are many positive points about the methodology in this paper. The authors involved two centres over 16 months and although the sample was obtained as a convenience sample, the wide inclusion and few exclusions mean that there’s a good chance that the population is representative of patients seen in my ED.

There are reasonable attempts to minimise bias:

  • Standardised training
  • Blinding of radiologists to US results/clinical findings
  • Standardised data collection sheet for clinical/examination findings
  • Composite reference standard (telephone follow-up)

In addition, it seems pragmatic – with only 1hr training plus 5 practice scans PEM clinicians could achieve an agreement of 0.94 with an experienced PEM sonologist! What concerns me slightly is how unclear it is who these PEM clinicians were. We can all think of the colleagues who would jump at the chance to take part in a study like this; the fact that only one sonologist had prior experience of elbow ultrasound does NOT mean that the others were inexperienced with US in general. Would these results be reproducible in the hands of a not-quite-sure-which-end-of-the-probe-goes-where EM clinician – even with an hour of training? I’m not so sure…

However, the study is nicely designed and would be relatively easy to replicate in your own department.

What were the results and what does this mean?

For diagnostic studies, it can be helpful to draw a 2×2 table. This allows the calculation of test characteristics. Below is a 2×2 table for the presence of posterior fat pad OR lipohaemarthrosis on elbow US.

    REFERENCE STANDARD
    Positive Negative Total
US Positive 42 26 68
Negative 1 61 62
Total 43 87 130

Sensitivity of 98% is not terrible, although the 95% confidence interval (88-100%) is pretty wide. This means the “true” sensitivity of elbow US in ED could be as low as 88%. Remember, high sensitivity means that when the test is negative we can effectively rule out the disease (fracture). Would we be happy to rule out at 88%? I don’t think so.

What’s most interesting is that the LR+ for elevated posterior fat pad AND lipohaemarthrosis is 5.8; that is, the proportion of patients who have a fracture and these findings is 5.8 times the proportion of patients with these findings who do not have a fracture. We can surmise that finding both elevated PFP and LH would be highly suggestive of an underlying fracture; but would this prevent an x-ray? Unlikely (pesky orthopods)! We don’t know quite how this correlates with the degree of required intervention (were these the fractures which needed to go to theatre; that were horrible looking supracondylar fractures from the outset?). And the LR- is not particularly brilliant when we look at the confidence intervals.

Not all patients who were followed-up had repeat XRs, but this reflects clinical practice and I think it is pretty reasonable not to XR a child who is pain-free with normal range of movement at their follow-up appointment. In fact, the radiation would be hard to justify. It is worth noting that four patients could not be followed-up; all had negative US and negative XR at their initial visit and were included in the “no fracture” group. The authors made reasonable attempts to follow-up these patients; how would the results be altered if we assumed the worst for these cases? And does it matter?

What can we take from this paper into clinical practice?

With appropriate training and practice, EM clinicians could use ultrasound to reliably exclude elbow fractures in children. However, a larger study is needed to tighten those confidence intervals; further training might also have this effect.

If both lipohaemarthrosis and elevated posterior fat pad are identified on US it is very likely that there is an underlying fracture, but would this change clinical practice? Probably not – yet 🙂

More questions to ask

  • Would more training/greater patient numbers narrow the confidence intervals (so we can effectively rule-out elbow fracture with ultrasound)?
  • Would the results be reproducible with a joe-bloggs ED clinician who’s a bit wobbly with an US probe (like me)?
  • Could we ever persuade orthopods to manage patients on the basis of US-diagnosed fractures without corresponding radiographs?

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9th November 2012: Improving Asthma Control with Medication Review in PED

Where can I find this paper?

http://www.ncbi.nlm.nih.gov/pubmed/23111345

What is this paper about (what is the research question)?

Can we improve the quality of life of paediatric asthmatic patients using the opportunity to increase their medications offered when they present to the ED?

Summary of the Paper

Design: Prospective cohort study

Objective: To assess the impact of improving control medications on quality of life in children with persistent asthma symptoms attending the PED.

Intervention: initiation or improvement of long term control medication – inhaled corticosteroid –  at discharge from PED following presentation with persistent asthma symptoms (in accordance with national guidelines).

Primary outcome: improvement in “Quality of Life”, defined as validated symptoms and quality of life scores (PACT and ARQoL), ascertained by parental reporting at telephone follow-up at 2 weeks, 6 weeks and 6 months after PED discharge.

Population: Patients presenting to PED of tertiary hospital in Bilbao (Spain) between May-December 2010 with persisent asthma symptoms

  • Inclusion: Children aged 1-14 years attending with acute asthma and persistent asthma symptoms with or without control medication
  • Exclusion: Children with chronic cardiopulmonary and neuromuscular conditions, children <1 year old, children <2 years old presenting with first episode of wheeze, children whose asthma control medication had been modified in preceding 4 weeks.

Results: 1954 asthma episodes of which 164 had persistent symptoms. 146 were included in the study with 22 lost to follow-up. At presentation, 50 (40.3%) were receiving maintenance treatment.

Asthma control medication was initiated in 74 patients (59.7%), improved within the same “step” in 36 (29.0%) and “stepped up” in 14 (11.3%).

Average PACT categorisation at 6 weeks was significantly lower than at 2 weeks (median 12, IQR 13.3 versus median 7.8 IQR 10, p<0.001) with improvement sustained at 6 months.

Mean ARQoL scores at 6 weeks and 6 months were significantly higher than those at 2 weeks (91.9 +/- 11.0 and 93.0 +/- 10.0 versus 86.1 +/- 14.3, p<0.001)

Authors’ Conclusions:

Where long term asthma control medications were initiated or stepped up following PED visit, children showed a decrease in persistent symptoms and improvement in quality of life.

On the study design

The lack of control group in this paper is a major downfall; children were presenting with intercurrent illness, a major confounder. We know from practice that asthma exacerbations are often associated with viral infection, and that wheeze and cough can persist for a few weeks afterwards. It is not surprising, then, that children were better 6 weeks and 6 months after attendance than at 2 weeks. How meaningful are these outcomes? It might be more useful to match patients with controls and demonstrate improvement, ideally through less subjective variables (time off school, hospital reattendance).

There is a risk of inclusion bias considering the seasonal recruitment.

The other issue is with data processing; subjective scores are qualitative or ordinal data at best. The study design seems to convert this to quantitative non-normal data for analysis. There is also significant confusion between averages: the authors state that “the mean PACT categorization was significantly lower”, then provide data for a median. These descriptive variables are suitable for different types of data; what kind of data did the authors have? I am no statistician but it does make me wonder whether they knew what they were doing – and whether we can trust their results and analysis.

What were the results and what does this mean?

It appears that the patients in the study had better quality of life and fewer asthma symptoms at 6 weeks and 6 months than at 2 weeks after PED discharge. However, the validity of this data is uncertain and even if the apparent improvement is reflected in real life, the lack of control group means we cannot attribute it to the introduction or adjustment of asthma medication.

What can we take from this paper into clinical practice?

Unfortunately, very little more than the idea that there might be a role for reviewing asthma medications in PED, in conjunction with a primary care physician.

More questions to ask

  • If we introduce a control group for comparison, does the adjustment or introduction of control medication improve quality of life/asthma symptoms?
  • Does this translate into objective outcomes such as reduced annual ED attendances/reduced school time missed?

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Videolaryngoscopy Vs Direct Laryngoscopy

2nd November 2012: Videolaryngoscopy Versus Direct Laryngoscopy in Simulated Paediatric Intubation

Where can I find this paper?

http://www.ncbi.nlm.nih.gov/pubmed/23083969

What is this paper about (what is the research question)?

In the setting of simulated paediatric intubation, is use of a videolaryngoscope associated with higher “success” rates than traditional direct laryngoscopy?

Summary of the Paper

Design: Prospective case-control study (subjects acting as own controls)

Objective: To compare the effect of videolaryngoscopy performed by trained Emergency Physicians on outcomes related to intubation.

Control: Direct laryngoscopy performed using videolaryngoscope with video display off (equivalent to laryngoscopy with Miller 0, Miller 1 or Mac 3 blade for neonate, infant and adult respectively)

Exposure: Videolaryngoscopy performed using Storz videolaryngoscope, with participants directed to watch the screen rather than looking into the oropharynx.

Intervention: Attempted intubation of three mannequins (neonate, infant and adult) in randomised order with or without presence of “pharyngeal swelling ” (determined by coin toss).

Primary outcome: “Successful” intubation, defined as successful placement of an endotracheal tube in the trachea of the simulation mannequin before removal of the laryngoscopy blade. The outcome was determined by unblinded post-attempt review of 3-point video footage by study investigators.

Population: Fellows and faculty in Paediatric Emergency Medicine volunteering to participate at a single tertiary care paediatric hospital (Philadelphia, USA).

  • Inclusion: Physicians with “adequate” training and experience with intubation
  • Exclusion: Fellows in their first year who had not completed requisite airway management training in the operating room

Results: 26 subjects performed 156 intubations Data was available for 148 intubations.

  • First attempt success in newborn: DL 20/24 (83%), VL 22/24 (92%). Difference 9% (95% CI: -9 to 28%)
  • First attempt success in infant: DL 21/24 (88%), VL 17/24 (71%). Difference -17% (95% CI: -38% to 5%)
  • First attempt success in adult: DL 10/26 (39%), VL 21/26 (81%). Difference 43% (95% CI: 18 to 67%, p=0.002)

First attempt success was significantly worse with VL than DL when pharyngeal swelling was turned on.

Authors’ Conclusions:

Paediatric emergency medicine providers had improved first-attempt success at intubation using videolaryngoscopy with a curved blade in an adult simulator; success rates with straight blades in neonatal and infant simulators were not significantly different between direct laryngoscopy and videolaryngoscopy.

On the study design

This was a small scale prospective study generating paired data. The subjects acted as their own “controls”, comparing normal DL technique with VL. There is considerable potential for selection bias in this study; subjects volunteered to participate. We can all imagine those of our colleagues most likely to volunteer to participate in this sort of study (and those who wouldn’t), and how this might skew or influence outcomes.

The scenario order was randomised, which increases the stringency of the methodology, but the lack of blinding of the investigators assessing the primary outcome is unfortunate as this might introduce an observation bias.

The introduction of the “pharyngeal swelling” component is an interesting one; the rationale for randomly including this complicating factor is unclear. While this might better represent “real life” clinical situations it does introduce a potential confounding factor for which the authors do not completely account. This might have been better placed in a separate study.

What were the results and what does this mean?

We can see from table 1 that there was a difference in time since last adult intubation between the “fellows” and the “attending physicians” which seems more significant than the for the other age groups, although there is no p-value given for this.

The investigators looked at comparative proportions of success between groups. The confidence intervals were wide but crossed zero in both the neonatal and infant mannequins, implying no evidence of significant difference in success rates. A bigger study would be expected to tighten these confidence intervals.

For the adult mannequin, the 95% confidence interval was similarly wide but did not cross zero. This suggests that the probability of observing a demonstrable difference in success rate between the groups if in fact there is no difference (the null hypothesis is true) is 0.2% (or 1 in 500). However the width of the confidence interval suggests that the “true” magnitude of the difference between the two observed groups could be between 18% and 67%.

What can we take from this paper into clinical practice?

Not much yet! The paper suggests that the use of a videolaryngoscope in the simulation setting does not significantly reduce intubation success in neonate and infant mannequins, and may improve performance in adult mannequins when used by skilled PED clinicians.

However, the controlled environment of the simulation room and the anatomy of the mannequin may well impact the realism of the situation, and the study is a proxy for clinical intubation success at best. More research is needed as the true value of videolaryngoscopy is still unclear.

More questions to ask

  • How does the use of videolaryngoscopy translate into clinical ED practice, particularly in a pressured environment?
  • Are these results reflected in physicians with less intubation experience?
  • Would training/experience with the videolaryngoscope improve performance further?

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26th October 2012: The Effect of Abdominal Pain Duration on the Accuracy of Diagnostic Imaging for Paediatric Appendicitis

Where can I find this paper?

http://www.ncbi.nlm.nih.gov/pubmed/22841176

What is this paper about (what is the research question)?

How do the test characteristics of US and CT change according to the duration of abdominal pain in the diagnosis of appendicitis in children?

Summary of the Paper

Design: secondary analysis of multicentre observational study

Outcome: presence or absence of appendicitis as determined by pathologist’s report of findings at surgery or composite telephone/medical record follow-up where surgery was not undertaken

Primary objective: to determine test performance characteristics of CT and ultrasonography according to the duration of abdominal pain in children being assessed for appendicitis

Population: ED patients aged 3-18 years presenting with acute abdominal pain of <96hrs duration

  • Inclusion: “possible appendicitis”, defined as patients who had blood tests, radiological studies (CT or USS or both), or surgical consultation for the purpose of diagnosing appendicitis
  • Exclusion: pregnancy, previous abdominal surgery, chronic GI conditions, severe developmental delay, CT or USS prior to ED assessment, pain >72h, no radiological examination performed.

Results: 2,349 patients in parent study, 1,810 in subgroup (1,216 had CT, 832 had USS).

38% had appendicitis (n=680).

With equivocal cases (radiology) removed:

  • OR of trend in CT: sensitivity 0.98, specificity 0.91, PPV 1.02, NPV 0.88
  • OR of trend in USS: sensitivity 1.40, specificity 1.15, PPV 1.26, NPV 1.26

With equivocal cases (radiology) included as positive:

  • OR of trend in CT: sensitivity 0.96, specificity 1.07, PPV 1.19, NPV 0.88
  • OR of trend in USS: sensitivity 1.39, specificity 1.10, PPV 1.19, NPV 1.26

Authors’ Conclusions:

The sensitivity and negative predictive value of ultrasonography increase with the duration of pain, and CT is less likely to be indeterminate with a longer duration of pain.

On the study design

This is a secondary analysis; this means the data used in the study was originally collected as part of another study, and is being analysed in new ways to answer different clinical questions. This approach is not uncommon; large studies generate a lot of data and it may be possible to identify related clinical patterns by subgroup and secondary analysis. Just remember that this is not the purpose for which these patients were recruited.

The ascertainment of duration of symptoms was completed on a standardised form before knowledge of CT or US results. This is a subjective outcome, so standardised forms help to increase objectivity. The kappa score (for inter-rater reliability) was 0.73 (95% CI 0.67-0.78) – not brilliant, particularly if we consider that the “true” K value could be as low as 67% agreement.

Abstraction rules were generated to help code US and CT findings to “normal”, “positive” or “equivocal”. The same is not true of the outcome measures: there is no mention of if and how uncertainty in the reports of the pathologist or surgeon was managed. Ambiguity in the reference standard would impact on the validity of the study. It is also unclear whether the pathologist and surgeon were blinded to the pre-operative radiological findings; this might also introduce an observation bias.

What were the results and what does this mean?

The authors give us various sensitivity, specificity, positive and negative predictive values for both CT and US at different time points, with odds ratios to express the relationship between increasing duration of pain and each test characteristic.

Table 2 shows us that as duration of symptom (pain) increases, whether equivocal cases are excluded or presumed positive, the sensitivity, specificity and negative predictive value of US increases. For CT, there is an improvement in positive predictive value when equivocal cases are included. But look at the confidence intervals. We can only be 95% sure that the true odds ratio is greater than 1 (i.e. the test statistic value increases) for sensitivity and NPV in US.

What can we take from this paper into clinical practice?

Serial US might be useful in equivocal cases, where clinical signs do not immediately necessitate surgery. The longer the history of symptoms (but <72h), the better a a negative ultrasound is at ruling appendicitis out. However, CT seems to offer more acceptable test characteristics regardless of duration of symptoms.

More questions to ask

  • What are the test characteristics when prospectively ascertained for clinically equivocal cases (since these are the patients we would not immediately take to theatre)?
  • How do these US findings compare to ED US?

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19th October 2012: Can We Reduce Ketamine-Associated Vomiting in Young Children?

Where can I find this paper?

http://www.ncbi.nlm.nih.gov/pubmed/23009186

What is this paper about (what is the research question)?

Ketamine, commonly used for paediatric procedural sedation in the ED, is associated with vomiting. Can we reduce the incidence of vomiting among this population by using adjunctive atropine or metoclopramide?

Summary of the Paper

Design: prospective, randomised, open, controlled study of children receiving ketamine sedation in the ED.

Outcome: incidence of ketamine-associated vomiting (KAV), either in the ED or within the first 24h after discharge

Primary objective: to compare incidences of KAV between patients receiving atropine and metoclopramide as an adjunct to ketamine (as prophylaxis against KAV), or ketamine alone.

Interventions: patients undergoing procedural sedation in the ED were randomised to receive IM ketamine (4mg/kg) for sedation either alone or in addition to atropine (0.01mg/kg) or metoclopramide (0.4mg/kg), administered IM in the same syringe as ketamine.

Population: tertiary hospital (Korea), with emergency medical centre and regional paediatric referral centre.

  • Inclusion: patients 4 months to 5 years of age, ASA class I or II receiving ketamine for laceration repair
  • Exclusion: concurrent illness involving vomiting; previous reaction to ketamine, atropine or metoclopramide; non-consent; contra-indications to trial drugs; inadequate sedation after first dose of IM ketamine.

 Results: convenience sample of patients presenting between October 2010 and September 2011. 1883 patients met inclusion criteria, 368 enrolled and randomised, 25 subsequently excluded due to sedation failure, 343 analysed in dept, 338 analysed by phone follow-up.

Vomiting occured either in the ED or after discharge in:

  • 28.4% of children receiving ketamine alone
  • 27.9% of the group receiving atropine + ketamine
  • 31.2% of the group receiving metoclopramide + ketamine

p value = 0.86 (no significant difference)

Authors’ Conclusions:

“We were unable to reduce ketamine-associated vomiting using adjunctive atropine or metoclopramide.”

On the study design

This is a pragmatic paper: there is little deviation from “normal” sedation practice, no fancy bits of equipment were used, and it is easy to see how (if you really wanted to) you could set up a similar study in your own department.

The use of telephone follow-up strengthens the conclusions the authors are able to draw; a not insignificant proportion of patients experiencing vomiting did so after discharge; they have achieved 97.9-99% telephone follow-up within each subgroup, which is helpful to us. Did they use intention-to-treat, and include those lost to follow-up in a worst case scenario (that they had vomited)? No, but they missing data is a relatively small proportion and equal among subgroups, so it is unlikely that this would have vastly altered their findings.

There is little ambiguity in their outcome measure; it is easy to imagine that a a patient either vomited or they didn’t. What would be interesting would be to know how patients who retched but didn’t actually vomit were classified.

A problem I have with this article is their patient cohort; I can accept their rationale for using IM ketamine in children under 5 years (although I don’t necessarily agree with it), but sedation at 4 months of age feels a little risky to me (and raises child protection concerns; how do 4-month-olds sustain -lacerations necessitating sedation for repair?). I wonder whether this truly represents practice across the world.

They also seemed nonplussed about starvation times for sedation. While this has been a contentious issue in the past (and a subject in need of a blog post elsewhere), I wonder whether this might affect their rates of vomiting with <25% starved for 6h (solids) in each subgroup.

What were the results and what does this mean?

No significant difference in vomiting between subgroups; the study has been powered to detect a difference between groups with 101 patients in each arm. You might note that this was not achieved in the metoclopramide arm (95 patients analysed in dept, 93 of these later analysed by telephone).

Rates of vomiting in dept or at telephone follow-up were similar between groups with around half as many patients vomiting at home as in the department.

Vomiting also seemed to be more likely in patients who had not been “adequately” starved, although this data has not been statistically analysed (presumably because the paper was not powered for this outcome).

What can we take from this paper into clinical practice?

There is no apparent reduction in post-procedure vomiting by adding metoclopramide or atropine to your IM ketamine sedation.

More questions to ask

  • Is this also true of ketamine sedation when drugs are administered by the IV route?
  • Would the same pattern be observed if patients were “adequately” starved?

Feedback Please!

As this is the first PEMLit Critical Appraisal post, it would be really helpful to get your feedback. Please feel free to comment below. We are particularly interested in your thoughts on the type of paper chosen and the format of the appraisal. Thanks for reading!

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Welcome to PEM Literature Review

PEMLit is a resource for doctors and healthcare workers interested in Paediatric Emergency Medicine. We believe in FOAM and support GMEP.

Each week, we rummage through the published literature to bring you an appraisal of the latest journal articles in PEM.

If you have an article you think we should appraise, please get in touch: you can email us at PEMLit@gmail.com or via twitter (@PEMLit).

Happy reading! #FOAMed