The noxious stimulus of laryngoscopy & tracheal intubation can precipitate hypertension, tachycardia, and intracranial pressure elevation, risking exacerbation of brain injury or haemorrhage. Physicians from an English Helicopter Emergency Medical Service examined the response of heart rate and blood pressure to prehospital rapid sequence intubation (RSI). While a retrospective study, the haemodynamic data were prospectively recorded and documented using standard monitor printouts, and time of intubation could be accurately determined by the onset of capnography recordings. Their standardised system documents blood pressure recordings every three minutes. Etomidate and suxamethonium were used for RSI.

They report their findings:

A hypertensive response occurred in 79% (70/89) of patients. MAP exceeded the upper limit of estimated intact cerebral autoregulation (150 mmHg) in 18% (16/89) of cases and 9% (8/89) of patients had a greater than 100% increase in MAP and/or SBP. A single hypotensive response occurred. A tachycardic response occurred in 58% (64/110) of patients and bradycardia was induced in one.

Of note, 97 of the 115 patients had injuries that included head trauma.

The authors note that opioids are often co-administered during in-hospital RSI and that this may offset the haemodynamic stimulation, while possible increasing the complexity of the procedure in the prehospital environment. They have modified their pre-hospital anaesthesia standard operating procedure to include the use of an opioid and will report the associated outcomes and complication rates ‘in due course’.

This is interesting and important stuff, and something we should all be looking at in our respective prehospital critical care services.

The haemodynamic response to pre-hospital RSI in injured patients
Injury. 2013 May;44(5):618-23
Abstract

I had some fun today getting intubated.

We used the Ambu aScope 2 and the Greater Sydney Area HEMS equipment and approach to airway management. I didn’t receive an antisialogogue or any analgesia or sedation.

The big learning point for me was how hard it was to anaesthetise the posterior part of my nasal cavity and nasopharynx. I thought the worst part would be any stimulation of my vocal cords or trachea with lidocaine or instrumentation, but this really was fine. Nebulised 2% lidocaine (the strongest concentration we have), atomised lidocaine (using a mucosal atomiser), and co-phenylcaine spray weren’t sufficient. I can see why people use pastes or gel to maintain mucosal contact while the lidocaine takes effect, but we don’t have those (yet). The best solution came from hooking up oxygen tubing to an iv cannula via a three way tap. Oxygen was run through at 2 l/min and lidocaine injected via the the three way tap. This enabled an atomised spray to be directed right onto the area concerned, and made the insertion of the nasotracheal tube more tolerable – although still unpleasant.

The fact I could be intubated awake with reasonable topicalisation suggests most patients should tolerate it perhaps after even an analgesic dose of ketamine, eg. 30-40 mg in an adult. I suspect full dissocation would not be required, which is good for cooperation (“stick your tongue out sir”). I appreciate there are better agents, such as remifentanil or dexmedetomidine, but my area of interest is the retrieval setting – where I have neither the luxury of using these agents nor that of calling for anaesthetic back up.

A video of the procedure will be uploaded to YouTube, which will demonstrate the airway topicalisation methods.

Thanks to HEMS physicians Emily Stimson, Nirosha De Zoysa, Felicity Day, Chloe Tetlow, and Fergal McCourt for making it fun and safe.

A score to predict difficulty of intubation in ICU patients underwent derivation and validation in French ICUs. The main predictors included Mallampati score III or IV, obstructive sleep apnoea syndrome, reduced mobility of cervical spine, limited mouth opening, severe hypoxia, coma, and where the operator was a nonanesthesiologist.

The striking thing is the overall rate of difficult intubations, defined as three or more laryngoscopy attempts or taking over 10 minutes using conventional laryngoscopy(!) and the high rate of severe complications.

The incidence of difficult intubation was 11.3% (113 of 1,000 intubation procedures) in the original cohort and 8% (32 of 400 intubation procedures) in the validation cohort.

In the development cohort, overall complications occurred in 437 of 1,000 intubation procedures (43.7%), with 381 (38.1%) severe complications (26 cardiac arrests, 2.6%; five deaths, 0.5%; 274 severe collapses, 27.4%; 155 severe hypoxemia, 15.5%) and 112 (11.2%) moderate complications (15 agitations, 1.5%; 32 cardiac arrhythmias, 3.2%; 23 aspirations, 2.3%; 48 esophageal intubations, 4.8%; six dental injuries, 0.6%).

There is no comment on incidence of propofol use for induction; I was tempted to speculate whether it was implicated in any of the cardiac arrests – something we observe time and again in the critically ill – but the authors state: “The drugs used for intubation, in particular neuromuscular blockers, did not differ between groups… However, midazolam use was more frequent in case of difficult intubation.“

Capnography was used only in 46% of intubations, and there was no mention of checklist use. It is fascinating how some aspects of airway management that might be considered minimum and basic safety standards in some practice settings are not yet routine in other specialties or locations.

An interesting study, from which one of the take home messages for me has to be a resounding ‘Yikes!’.

Early Identification of Patients at Risk for Difficult Intubation in the Intensive Care Unit
Am J Respir Crit Care Med. 2013 Apr 15;187(8):832-9
Abstract

A small pilot study on a convenience sample of children presenting to the emergency department with acute limb injury pain evaluated the use of intranasal ketamine(1).

Initial dose averaged 0.84 mg/kg and a third of the patients required a top up dose at 15 minutes, resulting in a total dose of about 1.0 mg/kg to provide adequate analgesia by 30 min for most patients. The authors suggest that this could guide investigators on an appropriate dose of IN ketamine for use in clinical trials.

Adverse events were all transient and mild.

Prior to administration, the ketamine was diluted with saline to a total volume of 0.5 mL and was administered as 0.25 mL per nare using a Mucosal Atomiser Device (MAD, Wolfe Tory Medical, Salt Lake City, UT, USA). According to the protocols in my Service, this device requires 0.1 ml to prime its dead space(2). It is unclear whether this factor may have affected the total dose delivered to the patient in this study.

1. Sub-dissociative dose intranasal ketamine for limb injury pain in children in the emergency department: A pilot study
Emerg Med Australas. 2013 Apr;25(2):161-7
Abstract

2. Case report: prehospital use of intranasal ketamine for paediatric burn injury
Emerg Med J. 2011 Apr;28(4):328-9
Abstract

One of the current Holy Grails of ED critical care is to find a reliable measure of fluid responsiveness in those patients with impaired organ perfusion, such as those with severe sepsis. This would enable us to identify those patients whose cardiac output would be improved by fluid therapy, and avoid subjecting ‘non-responders’ to the risks associated with fluid overload. Thanks to the uptake of early goal-directed therapy in sepsis, under-resuscitation is now much less common in the ED. However a growing evidence base reveals the dangers of over-resuscitation. We have a responsibility to optimise fluid therapy as best we can with the equipment we have, according to the latest evidence.

Inferior Vena Cava Ultrasound
Some tests of fluid responsiveness rely on the effect of respiration-induced changes in pleural pressure on the circulation. Inferior vena cava (IVC) size and degree of inspiratory collapse correlate with central venous pressure (CVP), but CVP is not a reliable predictor of volume status or responsiveness. Skinny, collapsing IVCs detected on ultrasound suggest volume responsiveness, but the lack of this finding does not exclude fluid responsiveness. IVC size and measurement can be affected by patient position, probe position, and a variety of health states from athleticism to increased abdominal pressure.

Pulse Pressure Variation
Respiratory pulse pressure variation derived from an arterial line trace in mechanically ventilated patients who are adequately sedated and receiving large tidal volumes can predict fluid responsiveness too. Variability in tidal volume, the presence of spontaneous breathing activity in a ventilated patient, and cardiac dysrhythmia can all confound the usefulness of this method.

End expiratory occlusion
Another test in mechanically ventilated patients is the end expiratory occlusion test. A positive pressure inspiratory breath cyclically decreases the left cardiac preload. Occluding the circuit at end-expiration prevents this cyclic impediment in left cardiac preload and acts like a fluid challenge. A 15 second expiratory occlusion is performed and an increase in pulse pressure or (if you can measure it) cardiac index predicts fluid responsiveness with a high degree of accuracy. The patient must be able to tolerate the 15 second interruption to ventilation without initiating a spontaneous breath.

Passive Leg Raise
Passive leg raising (PLR) involves measuring cardiac output (or its surrogate, velocity-time integral, or VTI) before and after tilting the semirecumbent patient supine and raising the legs to 45 degrees. This ‘autotransfuses’ blood from the lower limbs to the core and acts as a reversible fluid challenge. An increase in VTI identifies fluid responders. It would be nice if a PLR-induced increase in blood pressure revealed the answer, but BP does not reliably inform us of changes in cardiac output.

All these tests have limitations. Pulse pressure variation fails in patients with low respiratory system compliance, such as is found in ARDS(1). End-expiratory occlusion and PLR work in low respiratory system compliance, but the former still requires mechanical ventilation, and the latter requires a means of estimating cardiac output or a surrogate – oesophageal Doppler, the velocity-time integral measured by transthoracic echocardiography, and femoral artery flow (measured by arterial Doppler) have all been used. Non-invasive cardiac output monitors that are not operator dependent exist, such as the NICOM(TM) bioreactance device. Bioreactance cardiac output measurement is based on an analysis of relative phase shifts of an oscillating current that occurs when this current traverses the thoracic cavity. Its advantages are that it is noninvasive, it does not require endotracheal intubation or an arterial line, and it provides a good estimate of stroke volume in patients with atrial fibrillation.

A recent study evaluating the combination of PLR with NICOM(TM) bioreactance monitoring revealed that another tool could indicate volume responsiveness: an increase in carotid blood flow after PLR, as measured by carotid Doppler flow imaging(2). A threshold increase in carotid Doppler flow imaging of 20% for predicting volume responsiveness had a sensitivity and specificity of 94% and 86%, respectively. This was studied in a heterogenous group of hemodynamically unstable patients, suggesting applicability to the kind of patients who present to the ED, although numbers were small so more validation is required.

End-tidal carbon dioxide
End-tidal carbon dioxide (ETCO2) levels depend on cardiac output. Increasing cardiac output with a fluid challenge or PLR increases ETCO2,as long as ventilatory and metabolic conditions remain stable. In a recent small study, a PLR-induced increase in ETCO2 ≥ 5 % predicted a fluid-induced increase in cardiac index ≥ 15 % with sensitivity of 71 % (95 % confidence interval: 48-89 %) and specificity of 100 (82-100) %(3). The maximal effects of PLR on CI and ETCO2 were observed within 1 min.

So what can I use?
In summary, differentiating fluid responders from non-responders in the ED remains a challenge. The method used depends on available equipment and expertise, and whether the patient is spontaneously breathing or mechanically ventilated. The NICOM(TM) shows great promise but until your department can afford one, ultrasound is the way to go; small collapsing IVCs suggest fluid responders. Learning to measure a VTI on transthoracic echo or carotid Doppler flow will help you assess the response to a PLR in spontaneously ventilating patients. If they’re mechanically ventilated, then looking for an ETCO2 rise after PLR could be a simpler alternative.

 
I look forward to more studies on these modalities, and to trying some of them in the resus room at every available opportunity.

1. Passive leg-raising and end-expiratory occlusion tests perform better than pulse pressure variation in patients with low respiratory system compliance
Crit Care Med. 2012 Jan;40(1):152-7
Abstract

2. The use of bioreactance and carotid doppler to determine volume responsiveness and blood flow redistribution following passive leg raising in hemodynamically unstable patients
Chest. 2013 Feb 1;143(2):364-70
Abstract

3. End-tidal carbon dioxide is better than arterial pressure for predicting volume responsiveness by the passive leg raising test
Intensive Care Med. 2013 Jan;39(1):93-100
Abstract

A new breed, and new terminology

Scott Weingart MD and colleagues have published a discussion paper [1] outlining the role of emergency physicians who have completed additional critical care training – ED intensivists – and the potential benefits these individuals might bring to patients, emergency departments, and their emergency physician colleagues.

The paper also introduces a glossary of new terms which might help clarify future discussion of this practice area:

Potential benefits of ED-intensivists – and associated adequately staffed areas within ED that facilitate ongoing critical care delivery – include:

Scott’s whole mission is about bringing ‘upstairs care downstairs’, and educating others to do that, at which he is a true master. No doubt he will singlehandedly have inspired a large cohort of emergency physicians to train in critical care. Examples of ED intensivists and their roles are listed here on the EMCrit site.

Emergency physician intensivists in the Old Country

As an ‘ED-intensivist’ myself, I do believe many of those advantages can be realised. In the UK when I originally trained in both EM and ICM there was a small number of similarly trained individuals and we collectively called ourselves ‘EPIC’ – ‘Emergency Physicians in Intensive Care’.

Our shared energy and enthusiasm led to a dedicated conference in 2011 and it’s possible that our proselytizing combined with publications like Terry Brown’s ‘Emergency physicians in critical care: a consultant’s experience‘[2] may have made some small contribution to the subsequent explosion in interest in dual accreditation in EM & ICM in the UK.

Disappearing upstairs

When I moved to Australia in 2008 I was excited to hear that emergency docs now made up the largest proportion of dual trained new intensivists. When I asked a leading member of this group whether he saw any role for an ‘EPIC’ community in Australia I was surprised and disappointed with the response:

‘Nice idea but I don’t see the point. I can’t think of anyone who dual trained who’s still working in emergency medicine’

So it seems those who were in the best position to bring upstairs care downstairs had all disappeared upstairs. Many will admit it’s not just because they find critical care more interesting than emergency medicine; the combination of a significantly higher income (through private practice) with better working conditions plays a significant role.

There are other opportunities in Australia for emergency physicians to practice critical care. Prehospital & retrieval medicine services undertake interhospital critical care transport of patients from small and often remote facilities where all of the first few hours of intensive care must be delivered by retrieval teams in often challenging environments with limited personnel and equipment. In some cases it’s these retrieval physicians who are able to fulfil the role of ED-intensivist in their own EDs.

Integrated critical care models and SuperDoctors

Another Australian example is the ‘integrated critical care’ model pioneered in some regional centres in rural New South Wales where emergency physicians with critical care training aim to provide seamless care to patients in the prehospital, ED, ICU and ward environments. I was lucky enough to do some locum shifts in one of these centres – Tamworth – where the service is delivered by some of the most highly skilled and dedicated physicians I’ve ever met. Check out their registrar job ad for a flavour of their work. This model was described in a 2003 publication[3] by my Sydney HEMS colleague Craig Hore which lists its features as follows:

So it appears the benefits to patients, hospitals, and team skills of ED-intensivists have been espoused for some years in the Anglo-Australian setting, and different practice models evolve to best serve local need.

Resuscitating the resuscitationists

Is it time to revive EPIC? I chased up my UK buddies who co-founded it, and here are extracts from their replies (note ‘CCT’ refers to certificate of completion of training – the UK equivalent of specialist accreditation or board certification):

So it appears emergency physician intensivists are growing in number, but employment prospects in both specialties are not guaranteed. If we are to recruit them to work as ED intensivists (ie. providing critical care in the ED) we have a challenge in making such posts attractive and sustainable. Emergency medicine in the UK is suffering at the moment, and we’ll have to work hard to stop those who are dual trained from disappearing upstairs.

Your comments on this are invited. Should there be more critical care- trained EPs? Shouldn’t ALL EPs have the right critical care skills to manage the first few hours of critical care? Can you call yourself an emergency physician and not be a ‘resuscitationist’? Where do retrievalists fit into this spectrum? How do we help motivate those who are dual trained to stay in the ED for some of their time? Is there a need for a body like EPIC to guide those who are considering dual training, and to provide recommendations to employers and physicians on models of care and job planning? I would love to get more of an international perspective on this issue.

1. ED intensivists and ED intensive care units
Am J Emerg Med. 2013 Mar;31(3):617-20
Full text link available from here

2. Emergency physicians in critical care: a consultant’s experience
Emerg Med J. 2004 Mar;21(2):145-8
Full text link available from here
Abstract

3. Integrated critical care: an approach to specialist cover for critical care in the rural setting
Med J Aust. 2003 Jul 21;179(2):95-7
Abstract

A team from Los Angeles (including the great Kenji Inaba) has published a study on penetrating cardiac wounds in the pediatric population[1]. This is one of the largest studies on this thankfully rare event.

The outcome was poor which may be due to the high proportion of patients arriving at hospital without signs of life (SOL).

What I like about the paper is the discussion of their liberal policy for the use of resuscitative ED thoracotomy:

…we do not rely heavily on prehospital data regarding the precise timing of loss of SOL. Thus, at the discretion of the attending trauma surgeon, every penetrating injury to the chest with SOL lost during patient transport will be considered for ED thoracotomy.

In cases when a perfusing cardiac rhythm is regained, the patient will receive all operative and critical care support as standard of care. If the patient progresses to brain death, aggressive donor management will be implemented in accordance with consent obtained by the organ procurement organization.

In a recent publication, we observed two pediatric patients who underwent ED thoracotomy that subsequently became organ donors after brain death was declared [2]. A total of nine organs were recovered for transplantation. This contemporary outcome measure is of paramount importance in the current era of significant organ shortage.

When such aggressive resuscitative procedures are attempted on arrested trauma patients, there is a temptation to justify inaction on the grounds of futility or the risk of ‘creating a vegetable’. This paper reminds us that other outcome benefits may arise from attempted resuscitation even if the patient does not survive.

These benefits include the saving of other lives through organ donation. In addition to this, there is the opportunity for family members to be with their loved one on the ICU, to hold their warm hand for the last time, to hear the news broken by a team they have gotten to know and trust, to enact any spiritual or religious rites that may provide a source of comfort and closure, and to be there during withdrawal of life sustaining therapies after diagnosis of brain stem death. That will never be pleasant, but on the bleak spectrum of parental torture it may be better than being told the devastating news in the ED relatives’ room by a stranger they’ve never met but will remember forever.

The ED thoracotomy may at the very least remove any doubt that everything that could have been done, was done.

1. Penetrating cardiac trauma in adolescents: A rare injury with excessive mortality
Journal of Pediatric Surgery (2013) 48, 745–749
Abstract

2. Organ donation: an important outcome after resuscitative thoracotomy
J Am Coll Surg. 2010 Oct;211(4):450-5
Abstract

It is known that cricoid pressure can hinder laryngoscopic view of the cords during direct laryngoscopy. Using a Pentax-AWS Video laryngoscope, these authors have demonstrated that cricoid pressure can also worsen glottic view during video laryngoscopy.

Videographic Analysis of Glottic View With Increasing Cricoid Pressure Force
Ann Emerg Med. 2013 Apr;61(4):407-13
Abstract

Two recent studies evaluate the use of a novel ingestable camera to diagnose upper gastrointestinal bleeding in emergency department patients.

The potential advantages of video capsule endoscopy over traditional endoscopy could include immediate availability, avoidance of sedation, patient tolerance, and the ability to rule out active bleeding in the emergency department.

The device used was the PillCam ESO2 – shown here in this animation:

Further research is needed. These small interesting studies demonstrate the potential for this imaging technology to be used in stable patients presenting to emergency departments. Since it can only diagnose rather than treat, it would not appear to have any role in unstable patients.

Video capsule endoscopy in the emergency department: a prospective study of acute upper gastrointestinal hemorrhage.
Ann Emerg Med. 2013 Apr;61(4):438-443
Abstract

Capsule endoscopy in acute upper gastrointestinal hemorrhage: a prospective cohort study
Endoscopy. 2013 Jan;45(1):12-9
Abstract

Body temperature raises heart rate and respiratory rate in kids, potentially affecting our interpretation of these clinical signs.

Dutch investigators developed centile charts of respiratory rates for specific body temperatures (derivation study), so that abnormally high rates could be identified as a means of predicting lower respiratory infection (validation set).

Respiratory rate increased overall by 2.2 breaths/min per 1°C rise (standard error 0.2) after accounting for age and temperature in the model, which is similar to a previous UK study that suggested a rise in respiratory rate of around 0.5-2 breaths per minute and an increase in heart rate of about 10 beats per minute for every 1 degree celcius above normal.

Cut-off values at the 97th centile were more useful in detecting the presence of LRTI than existing (Advanced Paediatric Life Support) respiratory rate thresholds.

The respiratory rate charts are available here.

Derivation and validation of age and temperature specific reference values and centile charts to predict lower respiratory tract infection in children with fever: prospective observational study
BMJ. 2012 Jul 3;345:e4224

Free Full Text Link

This small study supports the hypothesis that therapeutic hypothermia can have positive inotropic effects in patients with cardiogenic shock of ischaemic or non-ischaemic origin.

Cooling resulted in a temperature-dependent decrease in heart rate and temperature-dependent increases in stroke volume index, cardiac index, mean arterial pressure, and cardiac power output. These changes reversed when the patients were rewarmed.

The authors summarise as follows:

In summary, our studies demonstrate that moderate hypothermia is feasible and safe also for patients in cardiogenic shock.

Improved cardiac performance may contribute to the considerable decrease of mortality for survivors of cardiac arrest, and the use of hypothermia can be recommended for patients with a clear indication for cooling and poor cardiac performance.

Moreover, hypothermia might be considered as a positive inotropic intervention during cardiogenic shock.

Moderate hypothermia for severe cardiogenic shock (COOL Shock Study I & II)
Resuscitation. 2013 Mar;84(3):319-25.
Abstract

The whole purpose behind my career and this blog is to save life. Like most emergency physicians I don’t see a huge number of resuscitation patients myself in a given week, so my best hope in making a difference is to develop my teaching skills so that I can motivate and inspire others to improve their ability to manage resuscitation.

The highlight of my week therefore has been the receipt of some email feedback from a colleague in Germany. An intensivist, internist, and prehospital doctor (I like him already) who tells me he found my ‘Own the Resus‘ talk helpful:

Dear Dr. Reid,

Few days ago, too tired too sleep after a long shift on my ICU (18 beds internal medicine ICU, I am specialist in internal medicine specialized in intensive care and prehospital emergency medicine in a major German city) I watched your talk via emcrit podcast. I was immediately caught, I soaked in every word, I was fascinated, watched it twice in the middle of the night and next afternoon I listened to it in my car driving to work.

At this very day I did some overdue crap beyond the end of my shift when I heard the ominous shuffling of feet and rolling of the emergency cart from the other end of the ward… “I think we need your help….”

There it was, difficult airway situation. Patient crashing.

Then what followed was a kind of “out of body experience”. I did what was necessary, made things happen like calling anesthesia difficult airway code, calling the surgeons, organizing fiber optics and meanwhile trying to secure that airway myself until i could dispatch anesthesia to the head and surgeons to the neck. Within few minutes there were 6 doctors and 5 nurses shuffling on 9 square meters…

I found myself 1 meter behind the foot end of the pts bed and with your talk in my head I found me consciously controlling the crowd. There was suddenly the messages of your talk and there was me. I don’t know how to put it into words, I wouldn’t have done something else in medical terms but thanks to your talk I had the vocabulary, the tools to reflect myself as the leader to be in charge of the situation somehow with more distance, and after a successful resus the 10 people involved in this code went off with a good feeling that everybody contributed in what they could and all for the pts benefit.

Your talk was a kind of transition to the next level for me: from the colleague who asks how to get out of trouble in many situations because he was often deeply in trouble, to the one who leads out of trouble.

With your talk many things suddenly became clear and I am looking forward to be able to work harder on this role of leading.

Thank you very much.

D

The whole purpose behind my career and this blog is to save life. Like most emergency physicians I don’t see a huge number of resuscitation patients myself in a given week, so my best hope in making a difference is to develop my teaching skills so that I can motivate and inspire others to improve their ability to manage resuscitation.

The highlight of my week therefore has been the receipt of some email feedback from a colleague in Germany. An intensivist, internist, and prehospital doctor (I like him already) who tells me he found my ‘Own the Resus‘ talk helpful:

Dear Dr. Reid,

Few days ago, too tired too sleep after a long shift on my ICU (18 beds internal medicine ICU, I am specialist in internal medicine specialized in intensive care and prehospital emergency medicine in a major German city) I watched your talk via emcrit podcast. I was immediately caught, I soaked in every word, I was fascinated, watched it twice in the middle of the night and next afternoon I listened to it in my car driving to work.

At this very day I did some overdue crap beyond the end of my shift when I heard the ominous shuffling of feet and rolling of the emergency cart from the other end of the ward… “I think we need your help….”

There it was, difficult airway situation. Patient crashing.

Then what followed was a kind of “out of body experience”. I did what was necessary, made things happen like calling anesthesia difficult airway code, calling the surgeons, organizing fiber optics and meanwhile trying to secure that airway myself until i could dispatch anesthesia to the head and surgeons to the neck. Within few minutes there were 6 doctors and 5 nurses shuffling on 9 square meters…

I found myself 1 meter behind the foot end of the pts bed and with your talk in my head I found me consciously controlling the crowd. There was suddenly the messages of your talk and there was me. I don’t know how to put it into words, I wouldn’t have done something else in medical terms but thanks to your talk I had the vocabulary, the tools to reflect myself as the leader to be in charge of the situation somehow with more distance, and after a successful resus the 10 people involved in this code went off with a good feeling that everybody contributed in what they could and all for the pts benefit.

Your talk was a kind of transition to the next level for me: from the colleague who asks how to get out of trouble in many situations because he was often deeply in trouble, to the one who leads out of trouble.

With your talk many things suddenly became clear and I am looking forward to be able to work harder on this role of leading.

Thank you very much.

D

Where I work high flow humidified nasal cannula oxygen (HFNC) is used for infants with bronchiolitis and our ICU also employs it for selected adult patients. This is a relatively recent addition to our choice of oxygen delivery systems, and many emergency physicians may still be unfamiliar with it.

A recent review outlines the (scant) evidence for its use in neonates, infants, and adults, and proposes some mechanisms for its effect.

It’s a bit like the traditional delivery of oxygen via nasal cannulae. However, it is recommended that flow rates above 6 l/min are heated and humidified, so the review referred to heated, humidified, high flow nasal cannulae (HFNC).

Neonates
HFNC began as an alternative to nasal CPAP for premature infants. There are as yet no definitive studies showing its superiority over CPAP.

Infants
HFNC may decrease the need for intubation when compared to standard nasal cannula in infants with bronchiolitis.

Adults
No hard outcome data yet exist. It has mainly been used for hypoxemic respiratory failure rather than patients with hypercarbia such as COPD patients.

How it works
The following are proposed mechanisms for improvements in gas exchange / oxygenation:

1. A high FiO2 is maintained because flow rates are higher than spontaneous inspiratory demand, compared with standard facemasks and low flow nasal cannulae which entrain a significant amount of room air.

2. Nasopharyngeal dead space ‘washout’. The additional gas flow within the nasopharyngeal space may  reduce dead space: tidal volume ratio. There are some animal neonatal data to show improved CO2 clearance with flows up to 8 l/min.

3. Stenting of the upper airway by positive pressure may decrease upper airways resistance and reduce work of breathing.

4. Some positive pressure (akin to CPAP) may be generated, which can help recruit lung and decrease ventilation–perfusion mismatch; however this is not consistently present in all studies, and high flows are needed to generate even modest pressures. For example, in a study on postoperative cardiac surgery patients, HFNC at 35 l/min generated a nasopharyngeal pressure of only 2.7 ± 1 cmH2O.

Drawbacks and things to know

Studies suggest that if benefit is going to be seen in adult or paediatric patients, this should be evident in the first 30-60 minutes.

Any modest positive pressure generated will be reduced by an open mouth or when there is a significant leak between the cannulae and the nares.

HFNC maintain a fixed flow and generate variable pressures, and the pressures may be more inconsistent in patients with respiratory distress with high respiratory rates and mouth breathing. Compare this with non-invasive ventilation (CPAP and or BiPAP) in which variable flow is used to generate a fixed pressure.

The authors’ summary is helpful:

We postulate that the predominant benefit of HFNC is the ability to match the inspiratory demands of the distressed patient while washing out the nasopharyngeal dead space. Generation of positive airway pressure is dependent on the absence of significant leak around the nares and mouth and seems less likely to be a predominant factor in relieving respiratory distress for most patients.

NIV such as CPAP and bilevel positive airway pressure should still be considered first line therapy in moderately distressed patients in whom supplementation oxygen is insufficient and when a consistent positive pressure is indicated.

There are numerous ongoing trials which should hopefully clarify indications for HFNC and the mechanisms by which it may be beneficial.

An earlier summary of the evidence was written by my Scandinavian chums. And Reuben Strayer uses it to optimise oxygenation during RSI as a modification of the NODESAT technique.

Use of high flow nasal cannula in critically ill infants, children, and adults: a critical review of the literature
Intensive Care Med. 2013 Feb;39(2):247-57
Abstract

An interesting animal study examined the techniques recommended in basic choking management algorithms for foreign body airway obstruction (chest and abdominal thrusts). In terms of the pressures generated, lateral chest thrusts were the most effective, although they are not recommended in current guidelines.

The technique described (on intubated pigs) was:

The animals were placed on the floor and on their side. The lower (dependent) side of the chest was braced by the ground and thrust was applied to the upper part of the upper side by two hands side by side with the higher one just below the axilla.

Interestingly – and I didn’t know this (although perhaps should have!) – the Australian Resuscitation Council (ARC) recommended lateral chest thrusts instead of abdominal thrusts for over 20 years.

While we should always exercise extreme caution in extrapolating animal studies to humans, this makes me want to consider lateral thrusts in the first aid (ie. no equipment) situation if other measures are failing.

Lateral versus anterior thoracic thrusts in the generation of airway pressure in anaesthetised pigs
Resuscitation. 2013 Apr;84(4):515-9
Abstract

If you’re in the United Kingdom on Thursday 21st March please consider watching BBC’s Horizon program at 9pm on BBC2.

I’m in Australia so I’ll miss it, but I’m moved by the whole background to this endeavour and really want you to help me spread the word.

Many of you will be familiar with the tragic case of Mrs Elaine Bromiley, who died from hypoxic brain injury after clinicians lost control of her airway during an anaesthetic for elective surgery. Her husband Martin has heroically campaigned for a greater awareness of the need to understand human factors in healthcare so such disasters can be prevented in the future.

Mr Bromiley describes the program, which is hosted by intensivist and space medicine expert Dr Kevin Fong:

Kevin and the Horizon team have produced something inspirational yet scientific, and – just as importantly – it’s by a clinician, for clinicians. It’s written in a way that will appeal to both those in healthcare and the public. It uses a tragic death to highlight human factors that all of us are prone to, and looks at how we can learn from others both in and outside healthcare to make a real difference in the future.

The lessons of this programme are for everyone in healthcare.

It would be wonderful if you could pass on details of the programme to anyone you know who works in healthcare. My goal is that by the end of this week, every one of the 1 million or so people who work in healthcare in the UK will be able to watch it (whether on Thursday or on iPlayer).

From the Health Foundation blog

Please help us reach this 1000 000 viewer target by watching on Thursday or later on iPlayer. Tweet about it or forward this message to as many healthcare providers you know. Help Martin help the rest of us avoid the kind of tragedy that he and his children have so bravely endured.

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Cliff

I made up a word a while ago: “dogmalysis”. It refers to the dissolution of authoritative tenets held as established opinion without adequate grounds.

DOGMA: something held as an established opinion; a point of view or tenet put forth as authoritative without adequate grounds

LYSIS: a process of disintegration or dissolution (as of cells)

It’s my favourite thing in medicine. I don’t why – perhaps because of my admiration since childhood for irreverent scientists who questioned authority, like Feynman and Sagan. Or perhaps it is because I think at times we physicians need to experience the humility of having our ignorance exposed. This is necessary to keep medicine science-based.

My undergraduate and much of my postgraduate training consisted of being taught medical certainties that I was required to regurgitate under exam conditions. The reality of clinical practice then revealed the awesome irreducible complexity of biology in our patients who ‘don’t read the textbooks’. As we learn in emergency medicine to navigate the perilous Bayesian jungle to a ‘very unlikely’ or ‘very likely’ life-threatening diagnosis, and when we have to weigh up the benefit:harm equation of an intervention that could either kill or cure, we begin to appreciate that certainty without evidence – dogma, or faith – can be lethal.

The problem is, however, that our human brains seem to thrive on it. We have evolved a whole senate of cognitive biases, which enable us to function well in everyday social situations, but which prevent us from conducting an impartial analysis of objective clinical data. An enlightening example of the degree to which our interpretation of the same information can vary is illustrated by a handful of trials on fibrinolytic therapy for stroke, producing a spectrum of reactions from aggressive promotion to skeptical opposition.

Being human, I have no doubt that I am occasionally dogmatic about topics to which I erroneously believe I have applied skepticism. I appreciate the courage of trainees who have the guts to challenge my assertions and who demand the evidence to justify them. Keep doing it. Keep asking. Keep challenging.

Keep lysing the dogma.

No-one said it better than Carl:

Dogmalytic posts

Ever heard anyone spout dogma along the lines of: “it’s a traumatic cardiac arrest – resuscitation is futile as the outcome is hopeless: survival is close to zero per cent”?

I have. Less frequently in recent years, I’ll admit, but you still hear it spout forth from the anus of some muppet in the trauma team. Here’s some recent data to add to the existing literature that challenges the ‘zero per cent survival’ proponents. A French study retrospectively analysed 167 traumatic cardiac arrests (TCAs). 6.6% achieved a complete neurological recovery (CNR), which increased to 9.4% if the first ambulance to arrive contained an advanced team including a physician. Rhythm and age were important: CNR was achieved in 36.4% of VFs, 7% of PEAs, and 2.7% of those in asystole; survival rate by age groups was 23.1% in children, 5.7% in adults, and 3.7% in the elderly.

Since traumatic arrest tends to affect a younger age group than medical arrests, the authors suggest:

“Avoiding the potential decrease in life expectancy in this kind of patient justifies using medical resources to their utmost potential to achieve their survival “

Since 2.7% of the asystolic patients achieved a CNR, the authors challenge the practice proposed by some authors that Advanced Life Support be withheld in TCA patients with asystole as the initial rhythm:

“had that indication been followed, three of our patients who survived neurologically intact would have been declared dead on-scene.”

I’d like to know what interventions were making the difference in these patients. They describe what’s on offer as:

In our EMS, all TCA patients receive ALS on-scene, which includes intubation, intravenous access, fluid and drug therapy, point-of-care blood analysis, and procedures such as chest drain insertion, pericardiocentesis, or Focused Assessment with Sonography for Trauma ultrasonography to improve the treatment of the cause of the TCA.

It appears that crystalloids and colloids are the fluid therapy of choice, and unlike many British and Australian physician-based prehospital services they made no mention of the administration of prehospital blood products.

Traumatic cardiac arrest: Should advanced life support be initiated?
J Trauma Acute Care Surg. 2013 Feb;74(2):634-8
Abstract

I want to clarify some terminology I use on a day-to-day basis, which is now so ingrained in my vocabulary that I forget that its meaning may not be obvious to all.

“You go in there and it looks like a chicken bomb has gone off…”

“..external muppet factors can delay preparation for transport”

Muppets

The first is ‘muppet’. This does not refer to the much loved and trademarked invention of Jim Henson, (and now property of Disney) – a word originally thought to be a synthesis of ‘marionette’ and ‘puppet’. If I were referring to these wonderful icons of children’s televisual theatre I would capitalise the ’m’. Nope. I refer to the British meaning, which the Oxford English Dictionary lists as: ‘an incompetent or foolish person’. However I apply it in the context of behaviour rather than character. A wealth of evidence has proven that good people can do bad things given the circumstances, and situational factors can lead us to behave in a way that we would not normally consider to be correct.

Certain situations can therefore lead our behaviour to at least appear to be incompetent or foolish. So perfectly good clinicians can appear to act like muppets during a resuscitation, given the circumstances. Various environmental and psychological factors contribute to this. Those factors generated within our own brains or bodies that influence our personal behaviour and performance have been called ‘internal muppet factors’. These include various cognitive errors such as inattention or fixation, or simple physiological stresses like fatigue or hunger. Those that relate to external forces such as environmental pressures or interaction with other team members are grouped under ‘external muppet factors’. These are most often a consequence of poor leadership and communication, and a lack of a shared mental model and agreed mission trajectory.

I had the privilege of working with Norwegian critical care doctor Per Bredmose, aka Viking One. He and I coined the terms internal and external muppet factors as a framework for debriefing resuscitation cases when attempting to understand the human factors involved. This was when we worked together in the UK in Basingstoke, where for the duration of my tenure we had a sign up on the wall in the resus room saying ‘No muppets’ (this now lives in my office in Sydney).

Chicken Bombs

When the external muppet factor is allowed to escalate unchecked, the end result is frenetic activity and noise from the staff without coordinated meaningful intervention for the patient. Comparisons with ‘headless chickens’ are often drawn. In particularly challenging scenarios, it can appear that the panic has swelled to such magnitude that it goes nova, as though the headless chickens have actually exploded, metaphorically filling the room with a gruesome blanket of giblets and a snowstorm of feathers, clouding ones ability to assess and manage the patient effectively. This high-point of group anxiety and ineffectiveness is what I mean by the term ’chicken bomb’, and I bet most readers of this blog will have witnessed the detonation of one.

I credit the invention of this term to emergency and prehospital physician James French, a master resuscitationist and human factors wizard who also introduced the idea of clinical logistics to us.

So, next time you encounter muppets and chicken bombs, feel free to use the terminology, although preferably not during an actual resus with those who might take it personally.

A large single-centre study in an academic tertiary care center emergency department (where residents perform most of the intubations) examined 1,828 orotracheal intubations, of which 1,333 were intubated successfully on the first attempt (72.9%).
Adverse events (AE) captured were oesophageal intubation, oxygen desaturation, witnessed aspiration, mainstem intubation, accidental extubation, cuff leak, dental trauma, laryngospasm, pneumothorax, hypotension, dysrhythmia, and cardiac arrest.

When the first pass was successful, the incidence of AEs was 14.2%. More than one attempt was associated with significantly more AEs. Patients requiring two attempts had 33% more AEs (47.2%) and as the number of attempts increased, so did the risk of AEs, with the largest increase in AEs occurring between an unsuccessful first attempt and the second intubation attempt.

This is a powerful argument in favour of optimising first pass success. We like to include this in a ‘first pass, no desat, no hypotension’ package that includes team simulation training, pre-intubation briefing, checklist use, optimisation of position, ketamine induction (and avoidance of propofol), apnoeic oxygenation, bougie use, bimanual laryngoscopy, and waveform capnography, as shown in this SMACC video:

Click here to view the embedded video.

The Importance of First Pass Success When Performing Orotracheal Intubation in the Emergency Department
Academic Emergency Medicine 2013;20(1):71–78, Free Full Text
Abstract

The group usually considered the universal donor for fresh frozen plasma because it contains no anti-A or anti-B antibodies is Type AB. Due to its limited availability the trauma service of the Mayo Clinic in Minnesota has been issuing thawed group A plasma to its flight crews who retrieve major trauma casualties from rural centres. This is given with packed group O red cells to patients who meet their prehospital massive transfusion protocol criteria. Some patients will inevitably receive ABO-incompatible plasma (namely patients with Group B or AB blood) which could theoretically give rise to haemolytic transfusion reactions, in which donor antibodies bind host red cells, activate complement, and give rise to anaemia, disseminated intravascular coagulation, acute kidney injury, and death. However:

• the transfusion of platelets containing ABO-incompatible plasma is common, with up to 2 units of incompatible plasma per apheresis platelet unit, whereas haemolytic reactions to platelets are rare (1 in 9,000 incompatible platelet transfusions);
• all reports of haemolytic reactions are caused by products that contain Group O plasma and there has never been a documented case of haemolysis as a result of products containing Group A plasma

A retrospective review showed no increased rates of adverse events with Type A compared with AB or ABO-compatible plasma. Since only a small absolute number of patients received an ABO-incompatible plasma transfusion, it could be argued that the study is underpowered (a point acknowledged by the authors). However this is very important and useful information for resource-limited settings.

Emergency use of prethawed Group A plasma in trauma patients
J Trauma Acute Care Surg. 2013 Jan;74(1):69-74
Abstract

The American Society of Anesthesiologists has published an update to its Practice Guidelines for Management of the Difficult Airway. You can get the full PDF for free. I’m linking to it for interest, but do not expect to find anything groundbreaking for the management of critical patients.

Practice Guidelines for Management of the Difficult Airway: An Updated Report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway
Anesthesiology 2013;118:251-70

Two randomised controlled trials have been published which compare endovascular stroke treatments with intravenous tPA. Both the American Interventional Management of Stroke (IMS) III trial (1) and the Italian SYNTHESIS Expansion trial (2) had Modified Rankin Scores as their primary endpoint. No significant differences in this outcome or in mortality or intracranial haemorrhage rates were found in either trial, and IMS III was terminated early due to futility.

A third trial, from North America, called MR RESCUE, randomised patients within 8 hours after the onset of large vessel, anterior-circulation strokes to undergo mechanical embolectomy or receive standard care(3). No clinical outcome differences were demonstrated.

An accompanying editorial (4) draws the following conclusion:

“The IMS III and SYNTHESIS Expansion studies show that intravenous thrombolysis should continue to be the first-line treatment for patients with acute ischemic stroke within 4.5 hours after stroke onset, even if imaging shows an occluded major intracranial artery. Beyond 4.5 hours, the MR RESCUE trial does not provide data supporting the use of endovascular treatment in patients with an ischemic penumbra of any size.”

Many might argue that showing endovascular treatment is equivalent to thrombolysis just means endovascular treatment doesn’t work, because a significant proportion of the emergency medicine community views this as the correct interpretation of a thorough analysis of the stroke thrombolysis literature.

1. Endovascular Therapy after Intravenous t-PA versus t-PA Alone for Stroke
NEJM Feb 8, 2013 Full Text Link

2. Endovascular Treatment for Acute Ischemic Stroke
NEJM Feb 8, 2013 Full Text Link

3. A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke
NEJM Feb 8, 2013 Full Text Link

4.Endovascular Treatment for Acute Ischemic Stroke — Still Unproven
NEJM Feb 8, 2013 Full Text Link

I ‘jumped ship’ from etomidate to ketamine for rapid sequence intubation (RSI) in sick patients about seven years ago. Good thing too, since I later moved to Australia where we don’t have etomidate. I’ve been one of the aggressive influences behind my prehospital service’s switch to ketamine as the standard induction agent for prehospital RSI. It’s no secret that I think propofol has no place in RSI in the critically ill.

I love ketamine for its haemodynamic stability compared with other induction agents. In fact, I very rarely see a drop in blood pressure when I use it for RSI even in significantly shocked patients. One should however try to remain open to evidence that disconfirms ones biases, lest we allow science to be replaced by religion. I therefore was interested to read a report of two cases of cardiac arrest following the administration of ketamine for rapid sequence intubation (RSI)(1).

The first case was a 25 year old with septic shock due to an intestinal perforation, with a respiratory rate of 30 ‘labored’ breaths per minute and hypoxaemia prior to intubation with 2mg/kg ketamine who became bradycardic and then had a 10-15 minute PEA arrest after ketamine administration (but prior to intubation). Pre-arrest oxygen saturation and pre-induction blood gases are not reported.

The second case was an 11 year old with septic shock and pneumonia, hypoxaemia, and a severe metabolic acidosis. She arrest with bradycardia then a brief period of asystole one minute after receiving 2.4 mg/kg ketamine with rocuronium for intubation.

Was the ketamine responsible for the arrests? Ketamine usually exhibits a stimulatory effect on the cardiovascular system, through effects which are incompletely understood but include a centrally mediated sympathetic response and probable inhibition of norepinephrine (noradrenaline) reuptake. However ketamine can have a direct depressant effect on cardiac output which is usually overridden by the sympathetic stimulation. In critically ill severely stressed patients the depressant effect may predominate. In a study on 12 critically ill surgical patients, haemodynamic indices were measured using pulmonary artery catheters within 5 minutes of ketamine administration (at a mean of 70 mg)(2). Six patients demonstrated decreases in ventricular contractility, and four had decreases in cardiac output. Mean arterial blood pressure decreased in four patients. The authors commented:

The patients..were septic, hypovolemic, or cirrhotic, and had severe stress preoperatively. It is possible that in these ill patients adrenocortical and catechol stores had been depleted prior to ketamine administration. Alternatively, in the setting of prolonged preoperative stress, there may be resistance to further sympathetic and/or adrenocotical stimulation by ketamine. In either case, preoperative stress may blunt the usual physiologic responses to ketamine, setting the stage for possible adverse effects.

The negative cardiovascular effects of ketamine may also be precipitated by larger doses or repeated doses of ketamine(3).

While this small case series of cardiac arrest following ketamine administration is interesting, we should bear in mind the other possible precipitants of arrest in these patients, which are not all discussed by the authors:

i) Both patients were hypoxaemic prior to induction and their peri-intubation oxygen saturations are not reported. Arrests following bradycardia at the time of induction in the critically ill are frequently related to hypoxaemia.

ii) The second patient had a severe metabolic acidosis and the first – an abdominal sepsis patient with a labored respiratory rate of 30 – very probably did too. A failure to match a patient’s compensatory respiratory alkalosis with hyperventilation after anaesthesia is known to precipitate arrest in acidaemic patients.

iii) Finally, if the ketamine was responsible for the arrests, one should consider that the doses given to these shocked and highly unstable patients were well in excess of what many of us would recommend, and doses in the range of 0.5-1 mg/kg might not have been associated with adverse effects.

The takehome points for me are that this report is a helpful reminder that the cardiovascular stimulation-inhibition balance of ketamine may be altered by severe critical illness, and that doses of any induction agent should be significantly reduced in the critically ill patient. In no way does this convince me that I should discard ketamine as my preferred choice for RSI in such patients.

1. Cardiac Arrest Following Ketamine Administration for Rapid Sequence Intubation
J Intensive Care Med. 2012 May 29. [Epub ahead of print]
Abstract

2. Cardiovascular effects of anesthetic induction with ketamine
Anesth Analg. 1980 May;59(5):355-8
Abstract

3. A comparison of some cardiorespiratory effects of althesin and ketamine when used for induction of anaesthesia in patients with cardiac disease
Br J Anaesth. 1976 Nov;48(11):1071-81
Abstract

Here’s a heads up on a major evidence-based medicine event in critical care: the results of two long awaited randomised controlled trials assessing high-frequency oscillation (HFOV) in Acute Respiratory Distress Syndrome (ARDS) have both been published, and the full text is available from the New England Journal of Medicine at the links below.

In summary, the Oscillation for Acute Respiratory Distress Syndrome Treated Early (OSCILLATE)(1) and the Oscillation in ARDS (OSCAR)(2) trials showed no improvement in in-hospital death or 30 day mortality, respectively. OSCILLATE was terminated early on the basis of a strong signal for increased mortality with HFOV.

An editorial discusses some of the reasons why these outcomes were seen, which include among other factors the possibility that they were related to increased requirements for sedation, paralysis, and vasoactive drugs in the HFOV patients that were not offset by improvements in oxygenation and lung recruitment.

1. High-Frequency Oscillation in Early Acute Respiratory Distress Syndrome
NEJM 22 Jan 2013
Click for abstract

2. High-Frequency Oscillation for Acute Respiratory Distress Syndrome
NEJM 22 Jan 2013
Click for abstract

The latest update of the Surviving Sepsis Campaign Guidelines has been released.

There’s too much interesting stuff to easily summarise, but luckily the full text article is available at the link below.
Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: 2012
Crit Care Med 2013 Feb;41(2):580-637 FREE FULL TEXT

A new study demonstrates an association between advanced prehospital airway management and worse clinical outcomes in patients with cardiac arrest. Done in Japan, the numbers of patients included are staggering: this nationwide population-based cohort study included 658 829 adult patients. They found that CPR with advanced airway management (use of tracheal tubes and even supraglottic airways) was a significant predictor of poor neurological outcome compared with conventional bag-valve-mask ventilation.

Association of Prehospital Advanced Airway Management With Neurologic Outcome and Survival in Patients With Out-of-Hospital Cardiac Arrest
JAMA 2013;309(3):257-66

Click to read abstract

Beautiful…

from the New Scientist site:

“It’s not a bird or a plane: it’s an unusual flying object that propels itself by flipping inside out. Created by engineers at Festo in Esslingen, Germany, the floating band filled with helium takes on different shapes while expanding and contracting to generate thrust and move through the air.“

Go to New Scientist to read more

Some good news for remote, rural, prehospital, and retrieval medicine clinicians who rely on point of care testing with the i-STAT® device. An animal study confirmed the reliability of testing aspirates from intraosseous samples taken from the tibia(1).

This is also good news for hospital practitioners when it comes to the acquisition of blood gas results, since there are concerns over the potential damage to blood gas analysers by bone marrow contents in the samples.

The researchers tested blood gases, acid–base status, lactate, haemoglobin, and electrolytes, and compared these with results from an arterial sample.

There was no malfunction of the equipment. Most of the acid–base parameters showed discrepancies between arterial and osseous samples: the average pH and base excess were consistently lower whilst pCO2 and lactate were higher in the intraosseous samples compared to the arterial. However the overall small degree and predictable direction of discrepancy in these values should preserve the clinical usefulness of intraosseous gases if these findings can be replicated in human subjects. pO2 was obviously very different between osseous and arterial samples.

They noted that aspiration of intraosseous samples was generally straightforward, especially immediately after placement of the cannulae, but on a few occasions more forceful aspiration was needed. They point out that this could possibly cause cellular lysis and affect the potassium analysis.

The authors consider the issue of how much aspirate should be discarded before taking a sample after intraosseous cannula insertion, and refer to a prior study which suggested that 2mL is adequate.

Summary

• Intraosseous aspirate can be tested on an i-STAT® point-of-care analyser
• Haemoglobin and electrolytes show good correlation with arterial samples
• Acid-base, pCO2, and lactate differ slightly from arterial results but in a predictable direction and results are still likely to be clinically useful in an emergency
• It may be worth discarding the first 2 ml of aspirate
• These results require validation in human subjects

Analysis of intraosseous samples using point of care technology–an experimental study in the anaesthetised pig
Resuscitation. 2012 Nov;83(11):1381-5
Click to read abstract

Fellow retrieval specialist and Royal North Shore Hospital emergency physician Dr Toby Fogg and coauthors have published their audit of intubations in an Australian Emergency Department(1). More important than the results themselves is that the process of monitoring ones practice inevitably leads to improvements. For example, at Toby’s institution an intubation checklist has been introduced since the audit began. Other Australasian EDs are encouraged to participate using the free resources at airwayregistry.org.au.

Recently we have also seen the publication of Korean registry data on paediatric intubations performed in 13 academic EDs over 5 years(2), in which first pass success rates (overall 67.6%) were higher with emergency physicians compared with paediatricians. Interestingly, a rapid sequence intubation technique was only used in 22.4% of intubations, which was more likely to be used by emergency physicians and was associated with a greater likelihood of first pass success.

This relatively low first pass success rate is reminiscent of the American study published in September(3) which raised some eyebrows with its 52% first pass intubation success rates in a paediatric ED, and which also showed that attending-level providers were 10 times more likely to be successful on the first attempt than all trainees combined. Possible reasons for such a low first pass success rate compared with adult registry data include the rigorous video analysis method used, or perhaps more likely that paediatric emergency subspecialists are exposed to fewer critical procedures, resuscitations, and intubations than their general emergency medicine counterparts(4).

As a specialty we must continue to seek to do better, and I salute all these brave authors who are telling it like it is. Particularly with children, whose airways are relatively easy, we have to develop the training, preparation, supervision, monitoring and feedback to aim for as high a success rate as possible.

Study authors Toby Fogg and Nick Annesley demonstrate the 'Happiness Triad'

1. Prospective observational study of the practice of endotracheal intubation in the emergency department of a tertiary hospital in Sydney, Australia
Emerg Med Australas. 2012 Dec;24(6):617-24
Click to read abstract

2. The factors associated with successful paediatric endotracheal intubation on the first attempt in emergency departments: a 13-emergency-department registry study
Resuscitation. 2012 Nov;83(11):1363-8
Click to read abstract

3.Rapid sequence intubation for pediatric emergency patients: higher frequency of failed attempts and adverse effects found by video review.
Ann Emerg Med. 2012 Sep;60(3):251-9
Click to read abstract

4. A is for airway: a pediatric emergency department challenge.
Ann Emerg Med. 2012 Sep;60(3):261-3