Category Archives: ICU

Stuff relevant to patients on ICU

Difficult intubation on ICU

icu-intub-iconA 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
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Rationale: Difficult intubation in the intensive care unit (ICU) is a challenging issue.

Objectives: To develop and validate a simplified score for identifying patients with difficult intubation in the ICU and to report related complications.

Methods: Data collected in a prospective multicenter study from 1,000 consecutive intubations from 42 ICUs were used to develop a simplified score of difficult intubation, which was then validated externally in 400 consecutive intubation procedures from 18 other ICUs and internally by bootstrap on 1,000 iterations.

Measurements and Main Results: In multivariate analysis, the main predictors of difficult intubation (incidence = 11.3%) were related to patient (Mallampati score III or IV, obstructive sleep apnea syndrome, reduced mobility of cervical spine, limited mouth opening); pathology (severe hypoxia, coma); and operator (nonanesthesiologist). From the β parameter, a seven-item simplified score (MACOCHA score) was built, with an area under the curve (AUC) of 0.89 (95% confidence interval [CI], 0.85-0.94). In the validation cohort (prevalence of difficult intubation = 8%), the AUC was 0.86 (95% CI, 0.76-0.96), with a sensitivity of 73%, a specificity of 89%, a negative predictive value of 98%, and a positive predictive value of 36%. After internal validation by bootstrap, the AUC was 0.89 (95% CI, 0.86-0.93). Severe life-threatening events (severe hypoxia, collapse, cardiac arrest, or death) occurred in 38% of the 1,000 cases. Patients with difficult intubation (n = 113) had significantly higher severe life-threatening complications than those who had a nondifficult intubation (51% vs. 36%; P < 0.0001).
Conclusions: Difficult intubation in the ICU is strongly associated with severe life-threatening complications. A simple score including seven clinical items discriminates difficult and nondifficult intubation in the ICU.

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Predicting volume responsiveness

IVCiconOne 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.

Fluid responsiveness assessment – options in the Emergency Department

Inferior Vena Cava Ultrasound
Helpful if skinny / large degree of respirophasic collapse – suggests fluid responsive – ventilated or spontaneous breathing

Passive Leg Raise
Good in ventilated or spontaneous breathing patients; need to measure cardiac output or a surrogate, such as VTI (echo), NICOM(TM), carotid Doppler flow, or ETCO2 (if ventilation and metabolic status constant)

Pulse Pressure Variation
Requires full mechanical ventilation; no good if low respiratory compliance / disturbed heart-lung interaction

End expiratory occlusion
Requires mechanical ventilation and patient tolerance of 15 seconds of apnoea. Acts like a passive leg raise so need a measure of cardiac output or surrogate

 
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
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OBJECTIVES: We tested whether the poor ability of pulse pressure variation to predict fluid responsiveness in cases of acute respiratory distress syndrome was related to low lung compliance. We also tested whether the changes in cardiac index induced by passive leg-raising and by an end-expiratory occlusion test were better than pulse pressure variation at predicting fluid responsiveness in acute respiratory distress syndrome patients.

DESIGN: Prospective study.

SETTING: Medical intensive care unit.

PATIENTS: We included 54 patients with circulatory shock (63 ± 13 yrs; Simplified Acute Physiology Score II, 63 ± 24). Twenty-seven patients had acute respiratory distress syndrome (compliance of the respiratory system, 22 ± 3 mL/cm H2O). In nonacute respiratory distress syndrome patients, the compliance of the respiratory system was 45 ± 9 mL/cm H2O.

MEASUREMENTS AND MAIN RESULTS: We measured the response of cardiac index (transpulmonary thermodilution) to fluid administration (500 mL saline). Before fluid administration, we recorded pulse pressure variation and the changes in pulse contour analysis-derived cardiac index induced by passive leg-raising and end-expiratory occlusion. Fluid increased cardiac index ≥ 15% (44% ± 39%) in 30 “responders.” Pulse pressure variation was significantly correlated with compliance of the respiratory system (r = .58), but not with tidal volume. The higher the compliance of the respiratory system, the better the prediction of fluid responsiveness by pulse pressure variation. A compliance of the respiratory system of 30 mL/cm H2O was the best cut-off for discriminating patients regarding the ability of pulse pressure variation to predict fluid responsiveness. If compliance of the respiratory system was >30 mL/cm H2O, then the area under the receiver-operating characteristics curve for predicting fluid responsiveness was not different for pulse pressure variation and the passive leg-raising and end-expiratory occlusion tests (0.98 ± 0.03, 0.91 ± 0.06, and 0.97 ± 0.03, respectively). By contrast, if compliance of the respiratory system was ≤ 30 mL/cm H2O, then the area under the receiver-operating characteristics curve was significantly lower for pulse pressure variation than for the passive leg-raising and end-expiratory occlusion tests (0.69 ± 0.10, 0.94 ± 0.05, and 0.93 ± 0.05, respectively).

CONCLUSIONS: The ability of pulse pressure variation to predict fluid responsiveness was inversely related to compliance of the respiratory system. If compliance of the respiratory system was ≤ 30 mL/cm H2O, then pulse pressure variation became less accurate for predicting fluid responsiveness. However, the passive leg-raising and end-expiratory occlusion tests remained valuable in such cases.

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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
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BACKGROUND: The clinical assessment of intravascular volume status and volume responsiveness is one of the most difficult tasks in critical care medicine. Furthermore, accumulating evidence suggests that both inadequate and overzealous fluid resuscitation are associated with poor outcomes. The objective of this study was to determine the predictive value of passive leg raising (PLR)- induced changes in stroke volume index (SVI) as assessed by bioreactance in predicting volume responsiveness in a heterogenous group of patients in the ICU. A secondary end point was to evaluate the change in carotid Doppler fl ow following the PLR maneuver.

METHODS: During an 8-month period, we collected clinical, hemodynamic, and carotid Doppler data on hemodynamically unstable patients in the ICU who underwent a PLR maneuver as part of our resuscitation protocol. A patient whose SVI increased by . 10% following a fluid challenge was considered a fluid responder.

RESULTS: A complete data set was available for 34 patients. Twenty-two patients (65%) had severe sepsis/septic shock, whereas 21 (62%) required vasopressor support and 19 (56%) required mechanical ventilation. Eighteen patients (53%) were volume responders. The PLR maneuver had a sensitivity of 94% and a specificity of 100% for predicting volume responsiveness (one false negative result). In the 19 patients undergoing mechanical ventilation, the stroke volume variation was 18.0% 5.1% in the responders and 14.8% 3.4% in the nonresponders ( P 5 .15). Carotid blood fl ow increased by 79% 32% after the PLR in the responders compared with 0.1% 14% in the nonresponders ( P , .0001). There was a strong correlation between the percent change in SVI by PLR and the concomitant percent change in carotid blood fl ow ( r 5 0.59, P 5 .0003). Using a threshold increase in carotid Doppler fl ow imaging of 20% for predicting volume responsiveness, there were two false positive results and one false negative result, giving a sensitivity and specificity of 94% and 86%, respectively. We noted a significant increase in the diameter of the common carotid artery in the fluid responders.

CONCLUSIONS: Monitoring the hemodynamic response to a PLR maneuver using bioreactance provides an accurate method of assessing volume responsiveness in critically ill patients. In addition, the study suggests that changes in carotid blood fl ow following a PLR maneuver may be a useful adjunctive method for determining fluid responsiveness in hemodynamically unstable patients.

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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
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PURPOSE: In stable ventilatory and metabolic conditions, changes in end-tidal carbon dioxide (EtCO(2)) might reflect changes in cardiac index (CI). We tested whether EtCO(2) detects changes in CI induced by volume expansion and whether changes in EtCO(2) during passive leg raising (PLR) predict fluid responsiveness. We compared EtCO(2) and arterial pulse pressure for this purpose.

METHODS: We included 65 patients [Simplified Acute Physiology Score (SAPS) II = 57 ± 19, 37 males, under mechanical ventilation without spontaneous breathing, 15 % with chronic obstructive pulmonary disease, baseline CI = 2.9 ± 1.1 L/min/m(2)] in whom a fluid challenge was decided due to circulatory failure and who were monitored by an expiratory-CO(2) sensor and a PiCCO2 device. In all patients, we measured arterial pressure, EtCO(2), and CI before and after a fluid challenge. In 40 patients, PLR was performed before fluid administration. The PLR-induced changes in arterial pressure, EtCO(2), and CI were recorded.

RESULTS: Considering the whole population, the fluid-induced changes in EtCO(2) and CI were correlated (r (2) = 0.45, p = 0.0001). Considering the 40 patients in whom PLR was performed, volume expansion increased CI ≥ 15 % in 21 “volume responders.” A PLR-induced increase in EtCO(2) ≥ 5 % predicted a fluid-induced increase in CI ≥ 15 % with sensitivity of 71 % (95 % confidence interval: 48-89 %) and specificity of 100 (82-100) %. The prediction ability of the PLR-induced changes in CI was not different. The area under the receiver-operating characteristic (ROC) curve for the PLR-induced changes in pulse pressure was not significantly different from 0.5.

CONCLUSION: The changes in EtCO(2) induced by a PLR test predicted fluid responsiveness with reliability, while the changes in arterial pulse pressure did not.

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Upstairs vs Downstairs: an EPIC Conundrum

A new breed, and new terminology

USAflagb&WResusScott 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:

Emergency medicine critical care a subspecialty of emergency medicine dealing with the care of the critically ill both in the ED and in the rest of the hospital

EP intensivist a physician who has completed a residency in emergency medicine and a fellowship in critical care

ED critical care emergency medicine critical care practiced specifically in the ED

ED intensivist (EDI) EPIs who practice ED critical care as a portion of their clinical time

Resuscitationists EPs who have additional knowledge, training, and interest in the care of the critically ill patient

EDICU a unit within an ED with the same or similar staffing, monitoring, and capability for therapies as an ICU

RED-ICU a hybrid resuscitation area and EDICU allowing a department to adopt the ED intensive care model with minimal cost and no changes to the physical plant

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

Full intensive care provided to patients unable to be moved to ICU (usually due to bed unavailability)

Development of protocols and care pathways that allow other EPs to deliver enhanced critical care

Gaining of advanced skills for ED nurses

Removal of need for ICU bed for conditions that can be improved in a few hours (eg. some overdoses, DKA, acute pulmonary oedema)

Cost saving due to decreased ICU stay (if the above ‘short term critical care’ patients are admitted to ICU, ward bed unavailability can make it difficult to discharge them from ICU)

Additional airway skills in ED (and training around that)

Improved invasive and non-invasive ventilatory management (and training) in ED

Gaining of ED experience in ventilator weaning and extubation

Gaining of ED experience in haemodynamic monitoring, vasoactive support, and even mechanical circulatory support (balloon pumps and ECMO)

Improved sepsis care

Improved post-cardiac arrest care

Improved trauma management

Greater exposure to invasive procedures

Improved end of life care

Better critical care exposure for trainees

Improved ED-ICU communication and shared protocols

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

epic__logoUKflagAs 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

AusflagWhen 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

ChrisTIconAnother 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:

Features of integrated critical care

Multiskilled critical-care specialists trained and experienced in the various aspects of critical care in rural hospitals.

Multidisciplinary critical-care teams that provide:

A more seamless interface between the various phases of critical care and between its respective disciplines;

A rapid response to, and a continuum of care for, critically ill and injured patients;

Clinical leadership in evaluating and managing critically ill and injured patients, both in the hospital (including the emergency department, critical-care unit and hospital wards) and in the community (including retrievals, and support for ambulance crews, peripheral hospitals and general practitioners); and

Training of medical students, medical staff, nursing staff and allied health professionals to recognise and provide a systematic approach to critical illness and injury.

Team members who are empowered to work beyond perceived traditional boundaries, but within the realms of their clinical expertise and credentials, to enable the best use of available resources.

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

UKflagIs 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):

“Interesting to hear that most Aussies leave EM, my experience of [our regional] trainees is the opposite; of 4 EM / ITU dual CCT over last 5 years, I’m the only one still doing a little bit of CCM, the rest have all ended up in full time EM posts, despite all doing periods of locum consultant work in CCM. (Although, after last 4 winter months of UK EM, I’m beginning to appreciate that I backed the wrong horse! (In the wrong country!!))”

“Having recently dropped ICU/ED 40/60 mix for full time ED i think those gravitating to ICU have a point – an error on my part. The ED represents much more intense work with fewer staff and a work load that far far exceeds resources. As such time to deliver care falls and skills with it. I have just spend 5 weeks [overseas]. I spent time with several directors who pointed out they no longer look to the UK for high quality ED docs as they manage depts as opposed to caring for patients, lack critical care skills and lack the experience to review and manage patients as they improve or deteriorate – a sad state of affairs indeed.”

“I would like to see EPIC back in force and do see an increasing role. around 1 in 4 of our trainees here are looking to joint qualify and we have 3 in their last 2 years. two are currently looking for posts but struggling to find any with a 50-50 mix and are been told to choose one or the other both by prospective ED and ICU employers.”

“I am concerned that dual trained folk here will, like in Australia gravitate to ICU. Whether that is a reflection of where EM is currently in the UK or a personal reflection I’m not sure. Where as I still have days in the ED where I come home and think ‘best job in the world’ these are overshadowed by the stresses of trying to deliver quality care in a failing system. My impression is that urgent care in the UK may well implode soon as ever decreasing workforce meets an over increasing work load. Inevitable closures of units will speed up this process. I currently have a 50/50 ICM/ED job split but that might change to become more ICU.”

“The ED/ICU community in the UK is growing and it wlll be interesting to see the effect of the ICM CCT has on this. There is sadly still a paucity of ED/ICU jobs in the UK and we probably missed a trick with the trauma centres.”

“It would be great to re-create EPIC to make it a real player for the future.”

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
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There is a growing interest in the interface between emergency medicine and critical care medicine. Previous articles in this journal have looked at the opportunities and advantages of training in critical care medicine for emergency medicine trainees. In the UK there are a small number of emergency physicians who also have a commitment to critical care medicine. This article describes a personal experience of such a job, looking at the advantages and disadvantages. Depending upon future developments in the role of emergency medicine in the UK, together with the proposed expansion in critical care medicine, such posts may become more common.

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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
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Critical care encompasses elements of emergency medicine, anaesthesia, intensive care, acute internal medicine, postsurgical care, trauma management, and retrieval. In metropolitan teaching hospitals these elements are often distinct, with individual specialists providing discrete services. This may not be possible in rural centres, where specialist numbers are smaller and recruitment and retention more difficult. Multidisciplinary integrated critical care, using existing resources, has developed in some rural centres as a more relevant approach in this setting. The concept of developing a specialty of integrated critical-care medicine is worthy of further exploration.

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Another argument for ED thoracotomy

ICM-iconA 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
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Background Penetrating cardiac injuries in pediatric patients are rarely encountered. Likewise, the in-hospital outcome measures following these injuries are poorly described.

Methods All pediatric patients (<18years) sustaining penetrating cardiac injuries between 1/2000 and 12/2010 were retrospectively identified using the trauma registry of an urban level I trauma center. Demographic and admission variables, operative findings, and hospital course were extracted. Outpatient follow-up data were obtained through chart reviews and cardiac-specific imaging studies.

Results During the 11-year study period, 32 of the 4569 pediatric trauma admissions (0.7%) sustained penetrating cardiac injuries. All patients were male and the majority suffered stab wounds (81.2%). The mean systolic blood pressure on admission was 28.8±52.9mmHg and the mean ISS was 46.9±27.7. Cardiac chambers involved were the right ventricle (46.9%), the left ventricle (43.8%), and the right atrium (18.8%). Overall, 9 patients (28.1%) survived to hospital discharge. Outpatient follow-up echocardiography was available for 4 patients (44.4%). An abnormal echocardiography result was found in 1 patient, demonstrating hypokinesia and tricuspid regurgitation.

Conclusions Penetrating cardiac trauma is a rare injury in the pediatric population. Cardiac chambers predominantly involved are the right and left ventricles. This injury is associated with a low in-hospital survival (<30%).

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2. Organ donation: an important outcome after resuscitative thoracotomy
J Am Coll Surg. 2010 Oct;211(4):450-5
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BACKGROUND: The persistent shortage of transplantable organs remains a critical issue around the world. The purpose of this study was to investigate outcomes, including organ procurement, in trauma patients undergoing resuscitative emergency department thoracotomy (EDT). Our hypothesis was that potential organ donor rescue is one of the important outcomes after traumatic arrest and EDT.

STUDY DESIGN: Retrospective study at Los Angeles County and University of Southern California Medical Center. Patients undergoing resuscitative EDT from January 1, 2006 through June 30, 2009 were analyzed. Primary outcomes measures included survival. Secondary outcomes included organ donation and the brain-dead potential organ donor.

RESULTS: During the 42-month study period, a total of 263 patients underwent EDT. Return of a pulse was achieved in 85 patients (32.3%). Of those patients, 37 (43.5%) subsequently died in the operating room and 48 (56.5%) survived to the surgical intensive care unit. Overall, 5 patients (1.9%) survived to discharge and 11 patients (4.2%) became potential organ donors. Five of the 11 potential organ donors had sustained a blunt mechanism injury. Of the 11 potential organ donors, 8 did not donate: 4 families declined consent, 3 because of poor organ function, and 1 expired due to cardiopulmonary collapse. Eventually 11 organs (6 kidneys, 2 livers, 2 pancreases, and 1 small bowel) were harvested from 3 donors. Two of the 3 donors had sustained blunt injury and 1 penetrating mechanism of injury.

CONCLUSIONS: Procurement of organs is one of the tangible outcomes after EDT. These organs have the potential to alter the survival and quality of life of more recipients than the number of survivors of the procedure itself.

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Cricoid can worsen VL View

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
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BACKGROUND:Cricoid pressure may negatively affect laryngeal view and compromise airway patency, according to previous studies of direct laryngoscopy, endoscopy, and radiologic imaging. In this study, we assess the effect of cricoid pressure on laryngeal view with a video laryngoscope, the Pentax-AWS.

METHODS: This cross-sectional survey involved 50 American Society of Anesthesiologists status I and II patients who were scheduled to undergo elective surgery. The force measurement sensor for cricoid pressure and the video recording system using a Pentax-AWS video laryngoscope were newly developed by the authors. After force and video were recorded simultaneously, 11 still images were selected per 5-N (Newton; 1 N = 1 kg·m·s(-2)) increments, from 0 N to 50 N for each patient. The effect of cricoid pressure was assessed by relative percentage compared with the number of pixels on an image at 0 N.

RESULTS: Compared with zero cricoid pressure, the median percentage of glottic view visible was 89.5% (interquartile range [IQR] 64.2% to 117.1%) at 10 N, 83.2% (IQR 44.2% to 113.7%) at 20 N, 76.4% (IQR 34.1% to 109.1%) at 30 N, 51.0% (IQR 21.8% to 104.2%) at 40 N, and 47.6% (IQR 15.2% to 107.4%) at 50 N. The number of subjects who showed unworsened views was 20 (40%) at 10 N, 17 (34%) at 20 and 30 N, and 13 (26%) at 40 and 50 N.

CONCLUSION: Cricoid pressure application with increasing force resulted in a worse glottic view, as examined with the Pentax-AWS Video laryngoscope. There is much individual difference in the degree of change, even with the same force. Clinicians should be aware that cricoid pressure affects laryngeal view with the Pentax-AWS and likely other video laryngoscopes.

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Hypothermia as an inotrope

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.
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AIM OF THE STUDY: Hypothermia exerts profound protection from neurological damage and death after resuscitation from circulatory arrest. Its application during concomitant cardiogenic shock has been discussed controversially, and still hypothermia is used with reserve when haemodynamic parameters are impaired. On the other hand hypothermia improves force development in isolated human myocardium. Thus, we hypothesized that hypothermia could beneficially affect cardiac function in patients during cardiogenic shock.

METHODS: 14 Patients, admitted to Intensive Care Unit for cardiogenic shock under inotropic support, were enrolled and moderate hypothermia (33°C) was induced for either one (n=5, short-term) or twenty-four (n=9, mid-term) hours.

RESULTS: 12 patients suffered from ischaemic cardiomyopathy, 2 were female, and 6 were included after cardiac arrest and resuscitation. Body temperature was controlled by an intravascular cooling device. Short-term hypothermia consistently decreased heart rate, and increased stroke volume, cardiac index and cardiac power output. Metabolic and electrocardiographic parameters remained constant during cooling. Improved cardiac function persisted during mid-term hypothermia, but was reversed during re-warming. No severe or persistent adverse effects of hypothermia were observed.

CONCLUSION: Moderate Hypothermia is safe and feasable in patients during cardiogenic shock. Moreover, hypothermia improved parameters of cardiac function, suggesting that hypothermia might be considered as a positive inotropic intervention rather than a risk for patients during cardiogenic shock.

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High flow nasal cannula oxygen

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
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BACKGROUND: High flow nasal cannula (HFNC) systems utilize higher gas flow rates than standard nasal cannulae. The use of HFNC as a respiratory support modality is increasing in the infant, pediatric, and adult populations as an alternative to non-invasive positive pressure ventilation.
OBJECTIVES: This critical review aims to: (1) appraise available evidence with regard to the utility of HFNC in neonatal, pediatric, and adult patients; (2) review the physiology of HFNC; (3) describe available HFNC systems (online supplement); and (4) review ongoing and planned trials studying the utility of HFNC in various clinical settings.
RESULTS: Clinical neonatal studies are limited to premature infants. Only a few pediatric studies have examined the use of HFNC, with most focusing on this modality for viral bronchiolitis. In critically ill adults, most studies have focused on acute respiratory parameters and short-term physiologic outcomes with limited investigations focusing on clinical outcomes such as duration of therapy and need for escalation of ventilatory support. Current evidence demonstrates that HFNC generates positive airway pressure in most circumstances; however, the predominant mechanism of action in relieving respiratory distress is not well established.
CONCLUSION: Current evidence suggests that HFNC is well tolerated and may be feasible in a subset of patients who require ventilatory support with non-invasive ventilation. However, HFNC has not been demonstrated to be equivalent or superior to non-invasive positive pressure ventilation, and further studies are needed to identify clinical indications for HFNC in patients with moderate to severe respiratory distress.

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Save a life by watching telly?

BB2.055If 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.
For more information on Mrs Bromiley’s case, watch ‘Just a Routine Operation’:


Cliff

Traumatic cardiac arrest outcomes

simEver 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 Spanish 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 their fluid therapy of choice; 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
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BACKGROUND: Several studies recommend not initiating advanced life support in traumatic cardiac arrest (TCA), mainly owing to the poor prognosis in several series that have been published. This study aimed to analyze the survival of the TCA in our series and to determine which factors are more frequently associated with recovery of spontaneous circulation (ROSC) and complete neurologic recovery (CNR).

METHODS: This is a cohort study (2006-2009) of treatment benefits.

RESULTS: A total of 167 TCAs were analyzed. ROSC was obtained in 49.1%, and 6.6% achieved a CNR. Survival rate by age groups was 23.1% in children, 5.7% in adults, and 3.7% in the elderly (p < 0.05). There was no significant difference in ROSC according to which type of ambulance arrived first, but if the advanced ambulance first, 9.41% achieved a CNR, whereas only 3.7% if the basic ambulance first. We found significant differences between the response time and survival with a CNR (response time was 6.9 minutes for those who achieved a CNR and 9.2 minutes for those who died). Of the patients, 67.5% were in asystole, 25.9% in pulseless electrical activity (PEA), and 6.6% in VF. ROSC was achieved in 90.9% of VFs, 60.5% of PEAs, and 40.2% of those in asystole (p < 0.05), and CNR was achieved in 36.4% of VFs, 7% of PEAs, and 2.7% of those in asystole (p < 0.05). The mean (SD) quantity of fluid replacement was greater in ROSC (1,188.8 [786.7] mL of crystalloids and 487.7 [688.9] mL of colloids) than in those without ROSC (890.4 [622.4] mL of crystalloids and 184.2 [359.3] mL of colloids) (p < 0.05).

CONCLUSION: In our series, 6.6% of the patients survived with a CNR. Our data allow us to state beyond any doubt that advanced life support should be initiated in TCA patients regardless of the initial rhythm, especially in children and those with VF or PEA as the initial rhythm and that a rapid response time and aggressive fluid replacement are the keys to the survival of these patients.

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The importance of first pass success

mv-vl-iconA 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. In the prehospital service I work for, 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.
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
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Objectives The goal of this study was to determine the association of first pass success with the incidence of adverse events (AEs) during emergency department (ED) intubations.

Methods This was a retrospective analysis of prospectively collected continuous quality improvement data based on orotracheal intubations performed in an academic ED over a 4-year period. Following each intubation, the operator completed a data form regarding multiple aspects of the intubation, including patient and operator characteristics, method of intubation, device used, the number of attempts required, and AEs. Numerous AEs were tracked and included events such as witnessed aspiration, oxygen desaturation, esophageal intubation, hypotension, dysrhythmia, and cardiac arrest. Multivariable logistic regression was used to assess the relationship between the primary predictor variable of interest, first pass success, and the outcome variable, the presence of one or more AEs, after controlling for various other potential risk factors and confounders.

Results Over the 4-year study period, there were 1,828 orotracheal intubations. If the intubation was successful on the first attempt, the incidence of one or more AEs was 14.2% (95% confidence interval [CI] = 12.4% to 16.2%). In cases requiring two attempts, the incidence of one or more AEs was 47.2% (95% CI = 41.8% to 52.7%); in cases requiring three attempts, the incidence of one or more AEs was 63.6% (95% CI = 53.7% to 72.6%); and in cases requiring four or more attempts, the incidence of one or more AEs was 70.6% (95% CI = 56.2.3% to 82.5%). Multivariable logistic regression showed that more than one attempt at tracheal intubation was a significant predictor of one or more AEs (adjusted odds ratio [aOR] = 7.52, 95% CI = 5.86 to 9.63).

Conclusions When performing orotracheal intubation in the ED, first pass success is associated with a relatively small incidence of AEs. As the number of attempts increases, the incidence of AEs increases substantially.

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