Tag Archives: anaesthesia

Convergent Evolution in the Jungles of Critical Care

boss-of-the-mob-1400090-1279x1923By Stuart Duffin
Expat Brit, intensive care physician and anaesthetist at Karolinska University Hospital in Stockholm, Sweden. Stuart trained in the UK, and spent some time working Australian emergency departments.
One of the most striking things for me about our new/old pan-specialty of critical care, brought into focus by the world-shrinking effects of FOAM and twitter, is just how differently it falls into the domains of the established specialities in different parts of the world. This leads inevitably to comments like, “emergency physicians shouldn’t intubate”, “anaesthetists cant do sick”, “nurses cant be doing such and such”, and so on. All of these statements are clearly equally rubbish because obviously, in certain parts of the world, they do. And they do it really well. Sure there are differences between countries and continents, populations and environments, but when it comes down to it, it doesn’t matter where you are, people still get sick, infected, pregnant, run over, stabbed or hit around the head with heavy things.
All over the world, in our previously quite isolated environments, these same ‘selection pressures’ have forced healthcare providers to evolve by the process of convergent evolution. Although obviously not strictly darwinian, the undeniable effects of simultaneous evolution by survival of the fittest-to-practice can be seen.
Convergent evolution is the process by which, in different parts of the world, completely different species have evolved in parallel to fill similar roles and have similar features. It didn’t matter whether it was a deer, a wildebeest or a kangaroo, there was a vacancy for a fairly big animal who liked eating grass and moved in big groups, and someone stepped up.
Unsurprisingly, critical care resuscitationists are also a little different from country to country and from continent to continent. They have different titles and work in slightly different ways. But when you really look at a critical care doc in action, or talk to one, or follow one on Twitter, we are all cut from the same cloth. I would argue that FOAM has created a critical care zoo in which the kangaroos and antelopes, lemurs and monkeys, aardvarks and echidnas and anaesthetists and emergency physicians are all chucked into the same cage. They’re all looking at each other thinking, “you look like me, but somehow not. We seem to do the same stuff, but we’re not identical – it cant be right!”.
In The United States, the idea of an anaesthetist doing a clamshell thoracotomy would be a little strange. In Scandinavia, an emergency physician doing central lines and fiberoptic intubation in resus would be just as eyebrow raising. A Swedish intensivist and anaesthetist spent some time working in Australia as an ICU senior reg. When attending a patient in resus the emergency physician there announced “we need an airway guy”. My colleague answered “I’m the airway guy”. “No an anaesthetist” replied the emergency physican. “I am an anaesthetist!” “No an….” and so it went on.
The effects of this process are of course by no means limited to doctors. Nurses, paramedics and physiotherapists are all part of this still changing ecosystem. A colleague of mine was showing a visiting Australian emergency physician our trauma bay and describing how major trauma is managed here without the involvement of emergency physicians at all. “When it’s really urgent, it’s anaesthesia and surgery” he explained. I wonder how that went down? There is an element of truth to the statement but the words are wrong. It should have been “When it’s really urgent, it’s airway, access, transfusion, invasive procedures and resuscitation thinking”.
The job title of the person who actually holds the knife/laryngoscope/needle and has what it takes to get it done isn’t important. When the push comes to shove and the bad stuff bounces off the fan, it’s more about skillset and mindset, and less about the collection of letters under your name on your badge, or after your name on your CV.

High flow systems for apnoeic oxygenation

nascaniconApnoeic oxygenation during laryngoscopy via nasal prongs has really taken off in the last couple of years in emergency department RSI, and is associated with decreased desaturation rates in out-of-hospital RSI.
More effective oxygenation and a small amount of PEEP can be provided by high flow nasal cannulae with humidified oxygen (HFNC)
A logical step in the progression of this topic is to consider HFNC for apnoeic oxygenation, and Reuben Strayer wrote about this nearly three years ago.
In a Twitter conversation today, Dr Pete Sherren highlighted a new article describing its use in anaesthesia for patients with difficult airways. This is labelled Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE). A reply from Dr Neil Brain points out that when used in kids, the bulkiness of the apparatus may get in the way of bag-mask ventilation (if that becomes necessary).
But does HFNC apnoeic oxygenation confer any advantages over standard nasal cannulae?
In an apnoeic patient, 15l/min via standard cannulae should fill the pharyngeal space with 100% oxygen, and you can’t improve on 100%.
HFNC provide some continuous positive pressure, but this may be cancelled by the necessary mouth opening for laryngoscopy.
One issue with apnoea is of course a rise in carbon dioxide with consequent acidosis. The authors of the THRIVE paper (abstract below) point out that in previous apnoeic oxygenation studies, the rate of rise of carbon dioxide levels was between 0.35 and 0.45 kPa/min (2.7-3.4 mmHg/min), whereas with THRIVE the rise was 0.15 kPa/min (1.1 mmHg/min). They suggest that continuous insufflation with high flow oxygen facilitates oxygenation AND carbon dioxide clearance through gaseous mixing and flushing of the deadspace.
So should we switch from standard nasal cannula to high flow cannulae for apnoeic oxygenation? I think not routinely, but perhaps consider it in patients:
(1) with pressure-dependent oxygenation (eg. ARDS) although I’m not sure any CPAP effect would be sustained during laryngoscopy
and
(2) in patients with significant acidosis in whom a significant rise in carbon dioxide could be detrimental (eg. diabetic ketoacidosis).
I look forward to reading more studies on this, and to hearing from anyone with experience of this technique in the comments section.
Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways.
Anaesthesia. 2014 Nov 10. doi: 10.1111/anae.12923. [Epub ahead of print]
[EXPAND Abstract]

Emergency and difficult tracheal intubations are hazardous undertakings where successive laryngoscopy-hypoxaemia-re-oxygenation cycles can escalate to airway loss and the ‘can’t intubate, can’t ventilate’ scenario.
Between 2013 and 2014, we extended the apnoea times of 25 patients with difficult airways who were undergoing general anaesthesia for hypopharyngeal or laryngotracheal surgery. This was achieved through continuous delivery of transnasal high-flow humidified oxygen, initially to provide pre-oxygenation, and continuing as post-oxygenation during intravenous induction of anaesthesia and neuromuscular blockade until a definitive airway was secured. Apnoea time commenced at administration of neuromuscular blockade and ended with commencement of jet ventilation, positive-pressure ventilation or recommencement of spontaneous ventilation. During this time, upper airway patency was maintained with jaw-thrust.
Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) was used in 15 males and 10 females. Mean (SD [range]) age at treatment was 49 (15 [25-81]) years. The median (IQR [range]) Mallampati grade was 3 (2-3 [2-4]) and direct laryngoscopy grade was 3 (3-3 [2-4]). There were 12 obese patients and nine patients were stridulous. The median (IQR [range]) apnoea time was 14 (9-19 [5-65]) min. No patient experienced arterial desaturation < 90%. Mean (SD [range]) post-apnoea end-tidal (and in four patients, arterial) carbon dioxide level was 7.8 (2.4 [4.9-15.3]) kPa. The rate of increase in end-tidal carbon dioxide was 0.15 kPa.min(-1) .
We conclude that THRIVE combines the benefits of ‘classical’ apnoeic oxygenation with continuous positive airway pressure and gaseous exchange through flow-dependent deadspace flushing. It has the potential to transform the practice of anaesthesia by changing the nature of securing a definitive airway in emergency and difficult intubations from a pressured stop-start process to a smooth and unhurried undertaking.

[/EXPAND]

Breaking with tradition in paediatric RSI

‘Traditional’ rapid sequence induction of anaesthesia is often described with inclusion of cricoid pressure and the strict omission of any artifical ventilation between paralytic drug administration and insertion of the tracheal tube. These measures are aimed at preventing pulmonary aspiration of gastric contents although there is no convincing evidence base to support that. However it is known that cricoid pressure can worsen laryngoscopic view and can occlude the paediatric airway. We also know that children desaturate quickly after the onset of apnoea, and although apnoeic diffusion oxygenation via nasal cannula can prevent or delay that, in some cases it may be preferable to bag-mask ventilate the patient while awaiting full muscle relaxation for laryngoscopy.
A Swiss study looked at 1001 children undergoing RSI for non-cardiac surgery. They used a ‘controlled rapid sequence induction and intubation (cRSII)’ approach for children assumed to have full stomachs. This procedure resembled RSI the way it is currently done in many modern critical care settings, including the retrieval service I work for:

  • No cricoid pressure
  • Ketamine for induction if haemodynamically unstable
  • A non-depolarising neuromuscular blocker rather than succinylcholine
  • No cricoid pressure
  • Gentle facemask ventilation to maintain oxygenation until intubation conditions achieved
  • Intubation with a cuffed tracheal tube
  • Still no cricoid pressure

The authors comment:
The main finding was that cRSII demonstrated a considerably lower incidence of oxygen desaturation and consecutive hemodynamic adverse events during anesthesia induction than shown by a previous study on classic RSII in children. Furthermore, there was no incidence of pulmonary aspiration during induction, laryngoscopy, and further course of anesthesia.
Looks like more dogma has been lysed, and this study supports the current trajectory away from traditional teaching towards an approach more suitable for critically ill patients.
Controlled rapid sequence induction and intubation – an analysis of 1001 children
Paediatr Anaesth. 2013 Aug;23(8):734-40
[EXPAND Abstract]

BACKGROUND: Classic rapid sequence induction puts pediatric patients at risk of cardiorespiratory deterioration and traumatic intubation due to their reduced apnea tolerance and related shortened intubation time. A ‘controlled’ rapid sequence induction and intubation technique (cRSII) with gentle facemask ventilation prior to intubation may be a safer and more appropriate approach in pediatric patients. The aim of this study was to analyze the benefits and complications of cRSII in a large cohort.
METHODS: Retrospective cohort analysis of all patients undergoing cRSII according to a standardized institutional protocol between 2007 and 2011 in a tertiary pediatric hospital. By means of an electronic patient data management system, vital sign data were reviewed for cardiorespiratory parameters, intubation conditions, general adverse respiratory events, and general anesthesia parameters.
RESULTS: A total of 1001 patients with cRSII were analyzed. Moderate hypoxemia (SpO2 80-89%) during cRSII occurred in 0.5% (n = 5) and severe hypoxemia (SpO2 <80%) in 0.3% of patients (n = 3). None of these patients developed bradycardia or hypotension. Overall, one single gastric regurgitation was observed (0.1%), but no pulmonary aspiration could be detected. Intubation was documented as ‘difficult’ in two patients with expected (0.2%) and in three patients with unexpected difficult intubation (0.3%). The further course of anesthesia as well as respiratory conditions after extubation did not reveal evidence of ‘silent aspiration’ during cRSII.
CONCLUSION: Controlled RSII with gentle facemask ventilation prior to intubation supports stable cardiorespiratory conditions for securing the airway in children with an expected or suspected full stomach. Pulmonary aspiration does not seem to be significantly increased.

[/EXPAND]

Atropine for Paediatric RSI?

paedRSIdrugiconIn some areas it has been traditional to pre-medicate or co-medicate with atropine when intubating infants and children, despite a lack of any evidence showing benefit. It is apparently still in the American Pediatric Advanced Life Support (PALS) Provider Manual when age is less than 1 year or age is 1–5 years and receiving succinylcholine. However it is not recommended with rapid sequence intubation in the British and Australasian Advanced Paediatric Life Support manual and course.
A French non-randomised observational study compares intubations with and without atropine in the neonatal and paediatric critical care setting. Atropine use was associated with significant acceleration of heart rate, and no atropine use was associated with a higher incidence of new dysrhythmia, the most common being junctional rhythm, but with none appearing to be clinically significant.
The incidence of the most important peri-intubation cause of bradycardia – hypoxia – is not reported. It is also not clear how many intubation attempts were required. The authors admit:
it is not possible using our methodology to deduce whether bradycardia was due to hypoxia, laryngoscopy, or sedation drugs.
Actual rapid sequence was rarely employed – their use of muscle relaxants was low – making this difficult to extrapolate to modern emergency medicine / critical care practice.
My take home message here is that this study provides no argument whatsoever for the addition of atropine in routine RSI in the critically ill child. Why complicate a procedure with an unnecessary tachycardia-causing drug when the focus should be on no desat / no hypotension / first look laryngoscopy?
The Effect of Atropine on Rhythm and Conduction Disturbances During 322 Critical Care Intubations
Pediatr Crit Care Med. 2013 Jul;14(6):e289-97
[EXPAND Abstract]


OBJECTIVES: Our objectives were to describe the prevalence of arrhythmia and conduction abnormalities before critical care intubation and to test the hypothesis that atropine had no effect on their prevalence during intubation.

DESIGN: Prospective, observational study.

SETTING: PICU and pediatric/neonatal intensive care transport.

SUBJECTS: All children of age less than 8 years intubated September 2007-2009. Subgroups of intubations with and without atropine were analyzed.

INTERVENTION: None.

MEASUREMENT AND MAIN RESULTS: A total of 414 intubations were performed in the study period of which 327 were available for analysis (79%). Five children (1.5%) had arrhythmias prior to intubation and were excluded from the atropine analysis. Atropine was used in 47% (152/322) of intubations and resulted in significant acceleration of heart rate without provoking ventricular arrhythmias. New arrhythmias during intubation were related to bradycardia and were less common with atropine use (odds ratio, 0.14 [95% CI, 0.06-0.35], p < 0.001). The most common new arrhythmia was junctional rhythm. Acute bundle branch block was observed during three intubations; one Mobitz type 2 rhythm and five ventricular escape rhythms occurred in the no-atropine group (n = 170). Only one ventricular escape rhythm occurred in the atropine group (n = 152) in a child with an abnormal heart. One child died during intubation who had not received atropine.

CONCLUSIONS: Atropine significantly reduced the prevalence of new arrhythmias during intubation particularly for children over 1 month of age, did not convert sinus tachycardia to ventricular tachycardia or fibrillation, and may contribute to the safety of intubation.

[/EXPAND]

Hyperchloraemia and mortality

Here’s something to add to the pile of data cautioning us to think before we acidify patients with saline. A study in Anesthesia and Analgesia using propensity matching provides retrospective evidence that patients who developed hyperchloremia after noncardiac surgery had worse outcomes.
For more information on why saline isn’t ‘normal’ see: What’s with all the chloride? An assault on salt
Hyperchloremia after noncardiac surgery is independently associated with increased morbidity and mortality: a propensity-matched cohort study
Anesth Analg. 2013 Aug;117(2):412-21
[EXPAND Abstract]


BACKGROUND: The use of normal saline is associated with hyperchloremic metabolic acidosis. In this study, we sought to determine the incidence of acute postoperative hyperchloremia (serum chloride >110 mEq/L) and whether this electrolyte disturbance is associated with an increase in length of hospital stay, morbidity, or 30-day postoperative mortality.

METHODS: Data were retrospectively collected on consecutive adult patients (>18 years of age) who underwent inpatient, noncardiac, nontransplant surgery between January 1, 2003 and December 31, 2008. The impact of postoperative hyperchloremia on patient morbidity and length of hospital stay was examined using propensity-matched and logistic multivariable analysis.

RESULTS: The dataset consisted of 22,851 surgical patients with normal preoperative serum chloride concentration and renal function. Acute postoperative hyperchloremia (serum chloride >110 mmol/L) is quite common, with an incidence of 22%. Patients were propensity-matched based on their likelihood to develop acute postoperative hyperchloremia. Of the 4955 patients with hyperchloremia after surgery, 4266 (85%) patients were matched to patients who had normal serum chloride levels after surgery. These 2 groups were well balanced with respect to all variables collected. The hyperchloremic group was at increased risk of mortality at 30 days postoperatively (3.0% vs 1.9%; odds ratio = 1.58; 95% confidence interval, 1.25-1.98) (relative risk 1.6 or risk increase of 1.1%) and had a longer hospital stay (7.0 days [interquartile range 4.1-12.3] compared with 6.3 [interquartile range 4.0-11.3]) than patients with normal postoperative serum chloride levels. Patients with postoperative hyperchloremia were more likely to have postoperative renal dysfunction. Using all preoperative variables and measured outcome variables in a logistic regression analysis, hyperchloremia remained an independent predictor of 30-day mortality with an odds ratio of 2.05 (95% confidence interval, 1.62-2.59).

CONCLUSION: This retrospective cohort trial demonstrates an association between hyperchloremia and poor postoperative outcome. Additional studies are required to demonstrate a causal relationship between these variables.

[/EXPAND]

Xenon – no bull?

Xenon, an inert ‘noble’ gas with proven anaesthetic properties, has possible neuroprotective properties and appears to be also cardioprotective in this small study of post-cardiac arrest patients. Its high viscosity affects airway resistance, resulting in higher peak pressures and the need for a strategy to avoid gas trapping (ie. longer expiratory times as with asthma). Apparently it’s expensive, but these results suggest further study is warranted.
Feasibility and Cardiac Safety of Inhaled Xenon in Combination With Therapeutic Hypothermia Following Out-of-Hospital Cardiac Arrest
Crit Care Med. 2013 Sep;41(9):2116-24
[EXPAND Abstract]


OBJECTIVES: Preclinical studies reveal the neuroprotective properties of xenon, especially when combined with hypothermia. The purpose of this study was to investigate the feasibility and cardiac safety of inhaled xenon treatment combined with therapeutic hypothermia in out-of-hospital cardiac arrest patients.

DESIGN: An open controlled and randomized single-centre clinical drug trial (clinicaltrials.gov NCT00879892).

SETTING: A multipurpose ICU in university hospital.

PATIENTS: Thirty-six adult out-of-hospital cardiac arrest patients (18-80 years old) with ventricular fibrillation or pulseless ventricular tachycardia as initial cardiac rhythm.

INTERVENTIONS: Patients were randomly assigned to receive either mild therapeutic hypothermia treatment with target temperature of 33°C (mild therapeutic hypothermia group, n = 18) alone or in combination with xenon by inhalation, to achieve a target concentration of at least 40% (Xenon + mild therapeutic hypothermia group, n = 18) for 24 hours. Thirty-three patients were evaluable (mild therapeutic hypothermia group, n = 17; Xenon + mild therapeutic hypothermia group, n = 16).

MEASUREMENTS AND MAIN RESULTS: Patients were treated and monitored according to the Utstein protocol. The release of troponin-T was determined at arrival to hospital and at 24, 48, and 72 hours after out-of-hospital cardiac arrest. The median end-tidal xenon concentration was 47% and duration of the xenon inhalation was 25.5 hours. The frequency of serious adverse events, including inhospital mortality, status epilepticus, and acute kidney injury, was similar in both groups and there were no unexpected serious adverse reactions to xenon during hospital stay. In addition, xenon did not induce significant conduction, repolarization, or rhythm abnormalities. Median dose of norepinephrine during hypothermia was lower in xenon-treated patients (mild therapeutic hypothermia group = 5.30 mg vs Xenon + mild therapeutic hypothermia group = 2.95 mg, p = 0.06). Heart rate was significantly lower in Xenon + mild therapeutic hypothermia patients during hypothermia (p = 0.04). Postarrival incremental change in troponin-T at 72 hours was significantly less in the Xenon + mild therapeutic hypothermia group (p = 0.04).

CONCLUSIONS: Xenon treatment in combination with hypothermia is feasible and has favorable cardiac features in survivors of out-of-hospital cardiac arrest.

[/EXPAND]

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
[EXPAND Abstract]


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.

[/EXPAND]

Updated Difficult Airway Guidelines

diffairwayThe 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

Lifting the Fogg on ED Intubaton

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
[EXPAND Click to read abstract]


OBJECTIVE: To describe the practice of endotracheal intubation in the ED of a tertiary hospital in Australia, with particular emphasis on the indication, staff seniority, technique, number of attempts required and the rate of complications.

METHODS: A prospective observational study.

RESULTS: Two hundred and ninety-five intubations occurred in 18 months. Trauma was the indication for intubation in 30.5% (95% CI 25.3-36.0) and medical conditions in 69.5% (95% CI 64.0-74.5). Emergency physicians were team leaders in 69.5% (95% CI 64.0-74.5), whereas ED registrars or senior Resident Medical Officers made the first attempt at intubation in 88.1% (95% CI 83.9-91.3). Difficult laryngoscopy occurred in 24.0% (95% CI 19.5-29.3) of first attempts, whereas first pass success occurred in 83.4% (95% CI 78.7-87.2). A difficult intubation occurred in 3.4% (95% CI 1.9-6.1) and all patients were intubated orally in five or less attempts. A bougie was used in 30.9% (95% CI 25.8-36.5) of first attempts, whereas a stylet in 37.5% (95% CI 32.1-43.3). Complications occurred in 29.0% (95% CI 23.5-34.1) of the patients, with desaturation the commonest in 15.7% (95% CI 11.9-20.5). Cardiac arrest occurred in 2.2% (95% CI 0.9-4.4) after intubation. No surgical airways were undertaken.

CONCLUSION: Although the majority of results are comparable with overseas data, the rates of difficult laryngoscopy and desaturation are higher than previously reported. We feel that this data has highlighted the need for practice improvement within our department and we would encourage all those who undertake emergent airway management to audit their own practice of this high-risk procedure.

[/EXPAND]
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
[EXPAND Click to read abstract]


BACKGROUND: We investigated which factors are associated with successful paediatric endotracheal intubation (ETI) on the first attempt in emergency department (EDs) from multicentre emergency airway registry data.

METHODS: We created a multicentre registry of intubations at 13 EDs and performed surveillance over 5 years. Each intubator filled out a data form after an intubation. We defined “paediatric patients” as patients younger than 10 years of age. We assessed the specialty and level of training of intubator, the method, the equipment, and the associated adverse events. We analysed the intubation success rates on the first attempt (first-pass success, FPS) based on these variables.

RESULTS: A total of 430 ETIs were performed on 281 children seen in the ED. The overall FPS rate was 67.6%, but emergency medicine (EM) physicians showed a significantly greater success rate of 74.4%. In the logistic regression analysis, the intubator’s specialty was the only independent predictive factor for paediatric FPS. In the subgroup analysis, the EM physicians used the rapid sequence intubation/intubation (RSI) method and Macintosh laryngoscope more frequently than physicians of other specialties. ETI-related adverse events occurred in 21 (7.2%) out of the 281 cases. The most common adverse event in the FPS group was mainstem bronchus intubation, and vomiting was the most common event in the non-FPS group. The incidence of adverse events was lower in the FPS group than in the non-FPS group, but this difference was not statistically significant.

CONCLUSIONS: The intubator’s specialty was the major factor associated with FPS in emergency department paediatric ETI, The overall ETI FPS rate among paediatric patients was 67.6%, but the EM physicians had a FPS rate of 74.4%. A well structured airway skill training program, and more actively using the RSI method are important and this could explain this differences.

[/EXPAND]
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
[EXPAND Click to read abstract]


STUDY OBJECTIVE: Using video review, we seek to determine the frequencies of first-attempt success and adverse effects during rapid sequence intubation (RSI) in a large, tertiary care, pediatric emergency department (ED).

METHODS: We conducted a retrospective study of children undergoing RSI in the ED of a pediatric institution. Data were collected from preexisting video and written records of care provided. The primary outcome was successful tracheal intubation on the first attempt at laryngoscopy. The secondary outcome was the occurrence of any adverse effect during RSI, including episodes of physiologic deterioration. We collected time data from the RSI process by using video review. We explored the association between physician type and first-attempt success.

RESULTS: We obtained complete records for 114 of 123 (93%) children who underwent RSI in the ED during 12 months. Median age was 2.4 years, and 89 (78%) were medical resuscitations. Of the 114 subjects, 59 (52%) were tracheally intubated on the first attempt. Seventy subjects (61%) had 1 or more adverse effects during RSI; 38 (33%) experienced oxyhemoglobin desaturation and 2 required cardiopulmonary resuscitation after physiologic deterioration. Fewer adverse effects were documented in the written records than were observed on video review. The median time from induction through final endotracheal tube placement was 3 minutes. After adjusting for patient characteristics and illness severity, attending-level providers were 10 times more likely to be successful on the first attempt than all trainees combined.

CONCLUSION: Video review of RSI revealed that first-attempt failure and adverse effects were much more common than previously reported for children in an ED.

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

Reassurance: difficult laryngoscopy in children remains rare

I was taught a useful principle by a paediatric anaesthetist 10 years ago which has proven true in my experience and has contributed to keeping me calm when intubating sick kids. Unlike adults, in whom difficulty in intubation can often be unexpected, the vast majority of normal looking children are easy to intubate, and the ones who are difficult usually have obvious indicators such as dysmorphism.
This appears to be supported by recent evidence: in a large retrospective series of 11.219 anaesthesia patients, the overall incidence of difficult laryngoscopy [Cormack and Lehane (CML) grade III and IV] was only 1.35%, although was much higher in infants less than one year compared with older children. This low percentage is in the same ball park as two other paediatric studies. Besides younger age, their database suggested underweight, ASA III and IV physical status and, if obtainable, Mallampati III and IV findings as predictors for difficult laryngoscopy. The authors point out:

…the oromaxillofacial surgery department with a high proportion of cleft palate interventions and pediatric cardiac surgery contributed substantially to the total number of difficult laryngoscopies. In patients undergoing pediatric cardiac surgery, a possible explanation for the higher incidence of CML III/IV findings might be that some congenital heart defects are associated with chromosomal anomalies like microdeletion 22q11.2 syndrome. This syndrome is also associated with extracardiac anomalies like cranio-facial dysmorphism

Take home message: As a very rough rule of thumb to illustrate the difference between the ease/difficulty of laryngoscopy between adults and kids, I think it’s fair to say grade III or IV views occur in about 10% of adults but only about 1% of children.

Incidence and predictors of difficult laryngoscopy in 11.219 pediatric anesthesia procedures
Paediatr Anaesth. 2012 Aug;22(8):729-36
[EXPAND Click for abstract]


OBJECTIVE: Difficult laryngoscopy in pediatric patients undergoing anesthesia.

AIM: This retrospective analysis was conducted to investigate incidence and predictors of difficult laryngoscopy in a large cohort of pediatric patients receiving general anesthesia with endotracheal intubation.

BACKGROUND: Young age and craniofacial dysmorphy are predictors for the difficult pediatric airway and difficult laryngoscopy. For difficult laryngoscopy, other general predictors are not yet described.

METHODS: Retrospectively, from a 5-year period, data from 11.219 general anesthesia procedures in pediatric patients with endotracheal intubation using age-adapted Macintosh blades in a single center (university hospital) were analyzed statistically.

RESULTS: The overall incidence of difficult laryngoscopy [Cormack and Lehane (CML) grade III and IV] was 1.35%. In patients younger than 1 year, the incidence of CML III or IV was significantly higher than in the older patients (4.7% vs 0.7%). ASA Physical Status III and IV, a higher Mallampati Score (III and IV) and a low BMI were all associated (P < 0.05) with difficult laryngoscopy. Patients undergoing oromaxillofacial surgery and cardiac surgery showed a significantly higher rate of CML III/IV findings.

CONCLUSION: The general incidence of difficult laryngoscopy in pediatric anesthesia is lower than in adults. Our results show that the risk of difficult laryngoscopy is much higher in patients below 1 year of age, in underweight patients and in ASA III and IV patients. The underlying disease might also contribute to the risk. If the Mallampati score could be obtained, prediction of difficult laryngoscopy seems to be reliable. Our data support the existing recommendations for a specialized anesthesiological team to provide safe anesthesia for infants and neonates.

[/EXPAND]