Tag Archives: dogmalysis


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


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.

Dogmalysis

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

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

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

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

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

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

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

Keep lysing the dogma.

No-one said it better than Carl:

Dogmalytic posts

 

 

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


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.

Perimortem Caesarean Delivery: Late is Better than Not


“To date, approximately one-third of the women who die during pregnancy remain undelivered at the time of death”

Guidelines recommend cardiac arrest in pregnant women beyond 20 weeks gestation should be treated with perimortem caesarean delivery (PMCD) commenced within 4 minutes of arrest and completed within 5. These time intervals come from two papers, neither of which is current or used robust review methodology.

To address this, an up-to-date fairly comprehensive review was undertaken of published cases of maternal cardiac arrests occurring prior to delivery. The primary outcome measures were maternal and neonatal survival to hospital discharge and the relationship between PMCD and this outcome.

The Arrests

94 cases were included in the final analysis.Most pregnancies were singleton (90.4%, n = 85) with an average gestational age at the time of the arrest of 33 ± 7 weeks (median 35, range 10–42).

The most common causes of arrest were trauma, maternal cardiac problems, severe pre-eclampsia and amniotic fluid embolism, together comprising about 70% of arrests; two thirds occurred in hospital.

The Outcomes

Overall, return of spontaneous circulation (ROSC) was achieved more often than not (60.6%) and overall survival to hospital discharge was 54.3%

Only 57 cases (75%) reported the time from arrest to delivery; the average time was 16.6 ± 12.5 min (median 10, range 1–60), with only 4 cases making it under the advocated 4-min time limit.

Timing of PMCD and Maternal Survival

In cases undergoing PMCD the average time elapsing from arrest to PMCD was significantly different between surviving (27/57) and non-surviving (30/57) mothers [10.0 ± 7.2 min (median 9, range 1–37) and 22.6 ± 13.3 min (median 20, range 4–60) respectively (p < 0.001, 95%CI 6.9–18.2)].

Timing of PMCD and Neonatal Survival

Mean times to PMCD were 14±11min (median=10, range=1–47) and 22 ± 13 min (median = 20, range = 4–60) in neonatal survivors and non-survivors respectively (p=0.016)

In cases with PMCD which reported outcome, the overall neonatal survival rate was 63.6% (42/66).


“The 4-min time frame advocated for PMCD usually remains unmet yet neonatal survival is still likely if delivery occurs within 10 or even 15 min of arrest”

Both maternal & neonatal mortality were higher with prehospital arrest location.

Summary

The study may be limited by recall bias, under-reporting and publication bias, but provides a more comprehensive evidence base on which to base resuscitation recommendations. The authors provide a useful warning against becoming fixated with the recommended four minute window, which may lead teams to fail to attempt a potentially life-saving intervention:


“Fixation on specific time frames for PMCD may not be ideal. It may be more important to focus on event recognition and good overall performance…. It may be wise to advocate a short time frame for performance of PMCD in order to achieve better outcomes; however, blanket endorsement of an unrealistic time frame may well create a defeatist attitude when that time frame cannot be met.”

Maternal cardiac arrest and perimortem caesarean delivery: Evidence or expert-based?
Resuscitation. 2012 Oct;83(10):1191-200


AIM: To examine the outcomes of maternal cardiac arrest and the evidence for the 4-min time frame from arrest to perimortem caesarean delivery (PMCD) recommended in current resuscitation and obstetric guidelines.

DATA SOURCES AND METHODS: Review and data extraction from all reported maternal cardiac arrests occurring prior to delivery (1980-2010). Cases were included if they provided details regarding both the event and outcomes. Outcomes of arrest were assessed using survival, Cerebral Performance Category (CPC) and maternal/neonatal harm/benefit from PMCD. Outcome measures were maternal and neonatal survival.

RESULTS: Of 1594 manuscripts screened, 156 underwent full review. Data extracted from 80 relevant papers yielded 94 included cases. Maternal outcome: 54.3% (51/94) of mothers survived to hospital discharge, 78.4% (40/51) with a CPC of 1/2. PMCD was determined to have been beneficial to the mother in 31.7% of cases and was not harmful in any case. In-hospital arrest and PMCD within 10 min of arrest were associated with better maternal outcomes (ORs 5.17 and 7.42 respectively, p<0.05 both). Neonatal outcome: mean times from arrest to delivery were 14±11 min and 22±13 min in survivors and non-survivors respectively (receiver operating area under the curve 0.729). Neonatal survival was only associated with in-hospital maternal arrest (OR 13.0, p<0.001).

CONCLUSIONS: Treatment recommendations should include a low admission threshold to a highly monitored area for pregnant women with cardiorespiratory decompensation, good overall performance of resuscitation and delivery within 10 min of arrest. Cognitive dissonance may delay both situation recognition and the response to maternal collapse.

London Calling – part 2

Notes from Days 2 & 3 of the London Trauma Conference

Day 2 of the LTC was really good. There were some cracking speakers who clearly had the ‘gift’ when it comes to entertaining the audience. No death by PowerPoint here (although it seems Keynote is now the presentation software of choice!). The theme of the day was prehospital care and major incidents.

The golden nuggets to take away include: (too many to list all of course)

  • ‘Pull’ is the key to rapid extrication from cars if time critical from the Norweigan perspective. Dr Lars Wik of the Norweigen air ambulance presented their method of rapid extrication. Essentially they drag the car back on the road or away from what ever it has crashed into to control the environment and make space (360 style). They put a paramedic in the car whilst this is happening. They then make a cut in the A post near the roof, secure the rear of the car to a fire truck or fixed object with a chain and put another chain around the lower A post and steering wheel that is then winched tight. This has the effect of ‘reversing’ the crash and a few videos showed really fast access to the patient. The car seems to peel open. As they train specifically for it, there doesn’t seem to be any safety problems so far and its much quicker than their old method. I guess it doesnt matter really how you organise a rapid extrication method as long as it is trained for and everyone is on the same page.
  • Dr Bob Winter presented his thoughts on hangings – to date no survivor of a non-judicial hanging has had a C-spine injury, so why do we collar them? Also there seems no point in cooling them. All imaging and concern for these patients should be based on the significant soft tissue injury that can be caused around the neck.
  • Drownings – if the patient is totally submerged probably reasonable to search for 30mins in water that is >6 degrees or 90mins if <6 degrees. After that it becomes a body recovery (unless there is an air pocket or some exceptional circumstance). Patients that have drowned should have early ventilatory support if they show any signs of resp distress.
  • Drs Julian Thompson and Mark Byers reassured us on a variety of safety issues at major incidents. It seems the risk to rescuers from secondary bombs at scene is low. Very few terrorist attacks world wide, ever, have had secondary devices so rescuers should be reassured (a bit). Greatest risk to the rescuer, like always, are the silly simple things that are a risk every day, like tripping over your own feet! With reference to chemical incidents, simple PPE seems to be sufficient for the vast majority of incidents, even fairly significant chemical ones, all this mucking about in full air tight suits is probably pointless and means patients cant be treated (at all). This led to the debate of how much risk should we, as rescue staff, accept? Clearly there are no absolute answers but minimising all risk to the rescuer is often at conflict with your ability to rescue. Where the balance should lie is a matter for organisations and individuals I guess.
  • Sir Prof Keith Porter also gave us an update on the future of Prehospital emergency medicine as a recognised medical specialty. As those in the know, know, the specialty has been recognised by the GMC and the first draft of trainees are currently in post. More deaneries will be following suit soon to begin training but it is likely to take some time to build up large numbers of trained specialists. Importantly for those of us who already have completed our training there will be an option to sub specialise in PHEM but it will involve undertaking the FIMC exam. Great, more exams – see you there.

 

Day 3 – Major trauma
The focus of day 3 was that of damage control. Damage control surgery and damage control resucitation. We had indepth discussions about how to manage pelvic trauma and some of the finer points of trauma resuscitation.

Specific points raised were:

  • Pelvic binders are great and can replace an ex fix if the abdomen needs opening to fix a spleen for example.
  • You can catheterise patients with pelvic fractures (one gentle try).
  • Most pelvic bleeds are venous which is why surgeons who can pack a pelvis is better than a radiologist who can mainly only treat arterial bleeds.
  • Coagulopathy in trauma is not DIC and is probably caused by peripheral hypoperfusion.
  • All the standard clotting tests that we use (INR etc) are useless and take too long to do. ROTEM or TEG is much better but still not perfect.

Also, as I am sure will please many – pressure isn’t flow so dont use pressors in trauma!

 

 

Chris Hill is an emergency and prehospital care physician based in the United Kingdom

Transtracheal airways in kids. Well, pigs’ kids anyway

Ever had to do a surgical airway in a child? Thought not. They’re pretty rare. Bill Heegaard MD from Henepin County Medical Center taught me a few approaches (with the help of an anaesthetised rabbit) which really got me thinking. It’s something I’d often trained for in my internal simulator, and I even keep the equipment for it in my house (listen out for an upcoming podcast on that). Research and experience has demonstrated that open surgical airway techniques are more reliable than transtracheal needle techniques in adults, but what about kids, in whom traditional teaching cautions against open techniques?

Australian investigators who were experienced airway proceduralists evaluated transtracheal needle techniques using a rabbit model (an excellent model for the infant airway). Their success rate was only 60% and they perforated the posterior tracheal wall in 42% of attempts. Of 13 attempts to insert a dedicated paediatric tracheotomy device, the Quicktrach Child, none were successful(1) (they did not use the Quicktrach Infant model as it is not available in Australia).

Danish investigators used fresh piglet cadavers weighing around 8 kg to assess two transtracheal cannulas, in which they achieved success rates of 65.6% and 68.8%(2). There was also a very high rate of posterior tracheal wall perforation. Using an open surgical tracheostomy technique, they were successful in 97% of attempts. These were also experienced operators, with a median anaesthetic experience of 12.5 years.

Their tracheotomy technique was nice and simple, and used just a scalpel, scissors, and surgical towel clips. Here’s their technique:

Simple tracheotomy procedure described by Holm-Knudsen et al
  1. Identify larynx and proximal trachea by palpation
  2. Vertical incision through the skin and subcutaneous tissue from the upper part of larynx to the sternal notch
  3. Grasp strap muscles with two towel forceps and separate in the midline
  4. Palpate and identify the trachea (palpate rather than look for tracheal rings, as in a live patient one would expect bleeding to obscure the view)
  5. Stabilise the trachea by grasping it with a towel forceps
  6. Insert sharp tip of the scissors between two tracheal rings and lift the trachea anteriorly to avoid damage to the posterior wall
  7. Cut vertically in the midline of the trachea with the scissors – they chose to use the scissors to cut the tracheal rings to facilitate tube insertion
  8. Insert the tracheal tube

Using ultrasound and CT to evaluate comparative airway dimensions, the authors concluded that the pig model is most useful for training emergency airway management in older children aged 5–10 years.

Why were they doing a tracheotomy rather than a cricothyroidotomy? Reasons given by the authors include:

  • The infant cricothyroid membrane is very small
  • Palpation of the thyroid notch may be hindered by the overlying hyoid bone
  • The mandible may obstruct needle access to the cricothyroid membrane given the cephalad position in the neck of the infant larynx.

From an emergency medicine point of view, there are a couple of other reasons why we need to be able to access the trachea lower than the cricothyroid membrane. One is fractured larynx or other blunt or penetrating airway injury where there may be anatomical disruption at the cricothyroid level. The other situation is foreign body airway obstruction, when objects may lodge at the level of the cricoid ring which is functionally the narrowest part of the pediatric upper airway. Of course, alternative methods might be considered to remove the foreign body prior to tracheotomy, such as employing basic choking algorithms, and other techniques depending on whether you do or don’t have equipment.

Take home messages
  • Transtracheal airways in kids are so rare, we can’t avoid extrapolating animal data
  • Whichever infant or paediatric model is used, transtracheal needle techniques have a high rate of failure even by ‘experienced’ operators
  • The small size and easy compressibility of the airway probably contributes to this failure rate, including the high rate of posterior wall puncture
  • In keeping with adult audit data, open surgical techniques may have a higher success rate
  • Tracheotomy may be necessary rather than cricothyroidotomy in infants and children depending on clinical scenario and accessibility of anatomy
  • The stress and blood that is not simulated in cadaveric animal models will make open tracheotomy harder in a live patient, and so these success rates may not translate. However these factors do mean that whatever technique is used must be kept simple and should employ readily available and familiar equipment
  • Something to maintain control and anterior position of the anterior trachea wall should be used during incision and intubation of the trachea. The study reported here used towel clips; sutures around the tracheal rings may also be used (see image below)

Sutures to stabilise trachea during infant tracheotomy simulation using a rabbit model

I recommend you add ‘paediatric tracheotomy’ to the list of procedures you might need to do (if it’s not already there). Identify what equipment you would use and run the simulation in your head and in your work environment.

Have fun.

1. The ‘Can’t Intubate Can’t Oxygenate’ scenario in Pediatric Anesthesia: a comparison of different devices for needle cricothyroidotomy
Paediatr Anaesth. 2012 Dec;22(12):1155-8


BACKGROUND: Little evidence exists to guide the management of the ‘Can’t Intubate, Can’t Oxygenate’ (CICO) scenario in pediatric anesthesia.

OBJECTIVES: To compare two intravenous cannulae for ease of use, success rate and complication rate in needle tracheotomy in a postmortem animal model of the infant airway, and trial a commercially available device using the same model.

METHODS: Two experienced proceduralists repeatedly attempted cannula tracheotomy in five postmortem rabbits, alternately using 18-gauge (18G) and 14-gauge (14G) BD Insyte(™) cannulae (BD, Franklin Lakes, NJ, USA). Attempts began at the first tracheal cartilage, with subsequent attempts progressively more caudad. Success was defined as intratracheal cannula placement. In each rabbit, an attempt was then made by each proceduralist to perform a cannula tracheotomy using the Quicktrach Child(™) device (VBM Medizintechnik GmbH, Sulz am Neckar, Germany).

RESULTS: The rabbit tracheas were of similar dimensions to a human infant. 60 attempts were made at cannula tracheotomy, yielding a 60% success rate. There was no significant difference in success rate, ease of use, or complication rate between cannulae of different gauge. Successful aspiration was highly predictive (positive predictive value 97%) and both sensitive (89%) and specific (96%) for tracheal cannulation. The posterior tracheal wall was perforated in 42% of tracheal punctures. None of 13 attempts using the Quicktrach Child(™) were successful.

CONCLUSION: Cannula tracheotomy in a model comparable to the infant airway is difficult and not without complication. Cannulae of 14- and 18-gauge appear to offer similar performance. Successful aspiration is the key predictor of appropriate cannula placement. The Quicktrach Child was not used successfully in this model. Further work is required to compare possible management strategies for the CICO scenario.

2. Emergency airway access in children – transtracheal cannulas and tracheotomy assessed in a porcine model
Paediatr Anaesth. 2012 Dec;22(12):1159-65


OBJECTIVES: In the rare scenario when it is impossible to oxygenate or intubate a child, no evidence exists on what strategy to follow.

AIM: The aim of this study was to compare the time and success rate when using two different transtracheal needle techniques and also to measure the success rate and time when performing an emergency tracheotomy in a piglet cadaver model.

METHODS: In this randomized cross-over study, we included 32 anesthesiologists who each inserted two transtracheal cannulas (TTC) using a jet ventilation catheter and an intravenous catheter in a piglet model. Second, they performed an emergency tracheotomy. A maximum of 2 and 4 min were allowed for the procedures, respectively. The TTC procedures were recorded using a video scope.

RESULTS: Placement of a transtracheal cannula was successful in 65.6% and 68.8% of the attempts (P = 0.76), and the median duration of the attempts was 69 and 42 s (P = 0.32), using the jet ventilation catheter and the intravenous catheter, respectively. Complications were frequent in both groups, especially perforation of the posterior tracheal wall. Performing an emergency tracheotomy was successful in 97%, in a median of 88 s.

CONCLUSIONS: In a piglet model, we found no significant difference in success rates or time to insert a jet ventilation cannula or an intravenous catheter transtracheally, but the incidence of complications was high. In the same model, we found a 97% success rate for performing an emergency tracheotomy within 4 min with a low rate of complications.

Needle decompression: it’s still not going to work

A pet topic that keeps coming up here is management of tension pneumothorax. Plenty of studies demonstrate that traditionally taught needle thoracostomy may fail, and open, or ‘finger’ thoracostomy is recommended for the emergency management of tension pneumothorax in a patient who is being ventilated with positive pressure (including those patients in cardiac arrest).

A recent CT scan-based study of adult trauma patients makes the case that needle decompression with a standard iv cannula would be expected to fail in 42.5% of cases at the second intercostal space (ICS) compared with 16.7% at the fifth ICS at the anterior axillary line (AAL).

The authors add an important point: “As BMI increases, there is a stepwise increase in chest wall thickness, further compounding the difficulty of needle placement in all but the lowest BMI quartile for the second ICS.”

An accompanying editorial cautions that the proximity of the heart may confer a safety issue if a needle is inserted blindly into the left 5th ICS at the AAL.


Objective To compare the distance to be traversed during needle thoracostomy decompression performed at the second intercostal space (ICS) in the midclavicular line (MCL) with the fifth ICS in the anterior axillary line (AAL).

Design Patients were separated into body mass index (BMI) quartiles, with BMI calculated as weight in kilograms divided by height in meters squared. From each BMI quartile, 30 patients were randomly chosen for inclusion in the study on the basis of a priori power analysis (n = 120). Chest wall thickness on computed tomography at the second ICS in the MCL was compared with the fifth ICS in the AAL on both the right and left sides through all BMI quartiles.

Setting Level I trauma center.

Patients Injured patients aged 16 years or older evaluated from January 1, 2009, to January 1, 2010, undergoing computed tomography of the chest.

Results A total of 680 patients met the study inclusion criteria (81.5% were male and mean age was 41 years [range, 16-97 years]). Of the injuries sustained, 13.2% were penetrating, mean (SD) Injury Severity Score was 15.5 (10.3), and mean BMI was 27.9 (5.9) (range, 15.4-60.7). The mean difference in chest wall thickness between the second ICS at the MCL and the fifth ICS at the AAL was 12.9 mm (95% CI, 11.0-14.8; P < .001) on the right and 13.4 mm (95% CI, 11.4-15.3; P < .001) on the left. There was a stepwise increase in chest wall thickness across all BMI quartiles at each location of measurement. There was a significant difference in chest wall thickness between the second ICS at the MCL and the fifth ICS at the AAL in all quartiles on both the right and the left. The percentage of patients with chest wall thickness greater than the standard 5-cm decompression needle was 42.5% at the second ICS in the MCL and only 16.7% at the fifth ICS in the AAL.

Conclusions In this computed tomography–based analysis of chest wall thickness, needle thoracostomy decompression would be expected to fail in 42.5% of cases at the second ICS in the MCL compared with 16.7% at the fifth ICS in the AAL. The chest wall thickness at the fifth ICS AAL was 1.3 cm thinner on average and may be a preferred location for needle thoracostomy decompression.

Radiologic evaluation of alternative sites for needle decompression of tension pneumothorax
Arch Surg. 2012 Sep 1;147(9):813-8

Don’t bronchodilators work in infants?

Inpatient paediatric teams can be scornful when bronchodilators are given by ED staff to wheezing infants, correctly referring to the lack of evidence of clinical benefit(1). There is however a persisting meme out there I’ve heard on a number of occasions that ‘young infants don’t have the receptors so inhaled beta agonists will never work.’ I’d love to know where this comes from.

Apparently, beta 2-receptors are present from the 16th gestational week(2). Pulmonary function testing of ventilated, very-low-birth-weight babies has shown that some consistently responded to beta-agonists whereas others did not(3). A newly published study reports that a quarter of mechanically ventilated infants with bronchiolitis were responders to inhaled albuterol, defined as a reduction in respiratory system resistance more than 30% below baseline(4).

In summary: beta-agonist bronchodilators have not been shown to improve clinical outcomes in wheezing infants. However some infants with some wheezing disorders will show a response in terms of pulmonary function. The receptors are there, and in life-threatening presentations bronchodilators should certainly be considered.

1. Short acting beta agonists for recurrent wheeze in children under 2 years of age
Cochrane Database Syst Rev. 2002;(3):CD002873


BACKGROUND: Wheeze is a common symptom in infancy and is a common cause for both primary care consultations and hospital admission. Beta2-adrenoceptor agonists (b2-agonists) are the most frequently used as bronchodilator but their efficacy is questionable.
OBJECTIVES: To determine the effectiveness of b2-agonist for the treatment of infants with recurrent and persistent wheeze.
SEARCH STRATEGY: Relevant trials were identified using the Cochrane Airways Group database (CENTRAL), Medline and Pubmed. The database search used the following terms: Wheeze or asthma and Infant or Child and Short acting beta-agonist or Salbutamol (variants), Albuterol, Terbutaline (variants), Orciprenaline, Fenoterol

SELECTION CRITERIA: Randomised controlled trials comparing the effect of b2-agonist against placebo in children under 2 years of age who had had two or more previous episodes of wheeze, not related to another form of chronic lung disease.
DATA COLLECTION AND ANALYSIS: Eight studies met the criteria for inclusion in this meta-analysis. The studies investigated patients in three settings: at home (3 studies), in hospital (2 studies) and in the pulmonary function laboratory (3 studies). The main outcome measure was change in respiratory rate except for community based studies where symptom scores were used.

MAIN RESULTS: The studies were markedly heterogeneous and between study comparisons were limited. Improvement in respiratory rate, symptom score and oxygen saturation were noted in one study in the emergency department following two salbutamol nebulisers but this had no impact on hospital admission. There was a reduction in bronchial reactivity following salbutamol. There was no significant benefit from taking regular inhaled salbutamol on symptom scores recorded at home.

REVIEWER’S CONCLUSIONS: There is no clear benefit of using b2-agonists in the management of recurrent wheeze in the first two years of life although there is conflicting evidence. At present, further studies should only be performed if the patient group can be clearly defined and there is a suitable outcome parameter capable of measuring a response.

2. The beta-2-agonists in asthma in infants and young children
Arch Pediatr. 2002 Aug;9 Suppl 3:384s-389s


Beta 2-agonists, by inducing a fast and long relaxation of the bronchial smooth muscle, are considered as the more potent bronchodilators. beta 2-receptors are present from the 16th gestational week, explaining a possible bronchial response in the youngest children. beta 2-agonists do not induce any bronchodilator response in healthy children. Short-acting beta 2-agonists (salbutamol or albuterol, terbutaline) are indicated for asthma attacks, as needed in chronic asthma, and for prevention of symptoms during effort. They are safe and secure. The more efficient route of administration in preschool children is pressurized metered-dose inhaler used with a spacer device. Therefore, whatever the route of inhalation chosen (inhalation, injection, or continuous nebulization in acute asthma attack), more specified indications and doses are needed in young children. Long-acting beta 2-agonists (formoterol, salmeterol) are not authorized in France in children under 4 to 5 years of age depending on the drug used. Because of new oral formulations and recent considerations about their use in asthma attack, instead of short-acting beta 2-agonists, their indication in preschool asthmatic children might be reconsidered.

3. Use of a beta-agonist in ventilated, very-low-birth-weight babies: a longitudinal evaluation
Dev Pharmacol Ther. 1990;15(2):61-7


To determine if there is a specific postnatal (PNA) or postconceptional age (PCA) at which ventilated preterm infants respond to beta-agonists, we evaluated 15 infants with a mean gestational age of 26.5 +/- 1.5 weeks and mean birth weight of 0.89 +/- 0.23 kg who required mechanical ventilation at 10 days of age. Weekly pulmonary function testing (PFT) was performed before and 1 h after administration of albuterol. Taking the group as a whole, as well as individual babies, regression analysis showed no relationship between positive response and either PNA or PCA. Evaluation of individual infants, however, showed that some consistently responded to beta-agonists whereas others did not. We recommend individual PFT to identify those infants who will benefit from use of beta-agonists.

4. Pulmonary mechanics following albuterol therapy in mechanically ventilated infants with bronchiolitis
J Asthma. 2012 Sep;49(7):688-96


BACKGROUND AND AIMS: Bronchiolitis is a common cause of critical illness in infants. Inhaled β(2)-agonist bronchodilators are frequently used as part of treatment, despite unproven effectiveness. The purpose of this study was to describe the physiologic response to these medications in infants intubated and mechanically ventilated for bronchiolitis.

MATERIALS AND METHODS: We conducted a prospective trial of albuterol treatment in infants intubated and mechanically ventilated for bronchiolitis. Before and for 30 minutes following inhaled albuterol treatment, sequential assessments of pulmonary mechanics were determined using the interrupter technique on repeated consecutive breaths.

RESULTS: Fifty-four infants were enrolled. The median age was 44 days (25-75%; interquartile range (IQR) 29-74 days), mean hospital length of stay (LOS) was 18.3 ± 13.3 days, mean ICU LOS was 11.3 ± 6.4 days, and mean duration of mechanical ventilation was 8.5 ± 3.5 days. Fifty percent (n = 27) of the infants were male, 81% (n = 44) had public insurance, 80% (n = 41) were Caucasian, and 39% (n = 21) were Hispanic. Fourteen of the 54 (26%) had reduction in respiratory system resistance (Rrs) that was more than 30% below baseline, and were defined as responders to albuterol. Response to albuterol was not associated with demographic factors or hospitalization outcomes such as LOS or duration of mechanical ventilation. However, increased Rrs, prematurity, and non-Hispanic ethnicity were associated with increased LOS.

CONCLUSIONS: In this population of mechanically ventilated infants with bronchiolitis, relatively few had a reduction in pulmonary resistance in response to inhaled albuterol therapy. This response was not associated with improvements in outcomes.

Is it time to abandon plain radiography in the trauma room?

For patients who will be having a chest CT, perhaps sonography could replace chest radiography in the resus room as the initial imaging step; this recent prospective study shows its superiority over the ‘traditional’ ATLS approach.

In haemodynamically stable patients with prophylactic pelvic splints in place, one could easily argue against plain pelvis films too (the caveat being rapid access to CT is necessary). The arguments against resus-room lateral cervical spine x-rays were made ages ago and these are now rarely done in the UK & Australia.

Is it time to abandon plain radiography altogether for stable major trauma patients?


Background: The accuracy of combined clinical examination (CE) and chest radiography (CXR) (CE + CXR) vs thoracic ultrasonography in the acute assessment of pneumothorax, hemothorax, and lung contusion in chest trauma patients is unknown.

Methods: We conducted a prospective, observational cohort study involving 119 adult patients admitted to the ED with thoracic trauma. Each patient, secured onto a vacuum mattress, underwent a subsequent thoracic CT scan after first receiving CE, CXR, and thoracic ultrasonography. The diagnostic performance of each method was also evaluated in a subgroup of 35 patients with hemodynamic and/or respiratory instability.

Results: Of the 237 lung fields included in the study, we observed 53 pneumothoraces, 35 hemothoraces, and 147 lung contusions, according to either thoracic CT scan or thoracic decompression if placed before the CT scan. The diagnostic performance of ultrasonography was higher than that of CE + CXR, as shown by their respective areas under the receiver operating characteristic curves (AUC-ROC): mean 0.75 (95% CI, 0.67-0.83) vs 0.62 (0.54-0.70) in pneumothorax cases and 0.73 (0.67-0.80) vs 0.66 (0.61-0.72) for lung contusions, respectively (all P < .05). In addition, the diagnostic performance of ultrasonography to detect pneumothorax was enhanced in the most severely injured patients: 0.86 (0.73-0.98) vs 0.70 (0.61-0.80) with CE + CXR. No difference between modalities was found for hemothorax.


Conclusions: Thoracic ultrasonography as a bedside diagnostic modality is a better diagnostic test than CE and CXR in comparison with CT scanning when evaluating supine chest trauma patients in the emergency setting, particularly for diagnosing pneumothoraces and lung contusions.

Diagnostic accuracy of ultrasonography in the acute assessment of common thoracic lesions after trauma
Chest. 2012 May;141(5):1177-83

Head injury was not predictive for cervical spine injury

Two papers examining the same massive European trauma dataset identify risk factors for spinal injury. The first examined all spinal injury(1), and the most recent focuses on cervical injury(2). Male gender, decreased GCS, falls > 2m, sports injuries, and road traffic collisions were predictors of any fracture/dislocation or cord injury. Head injury was not an independent risk factor, contrary to much popular teaching. I’ve summarised the two papers’ findings in this table. The odds ratios are reported in the abstracts.

Download Keynote presentation slide (for Mac)

1. Epidemiology and predictors of spinal injury in adult major trauma patients: European cohort study
Eur Spine J. 2011 Dec;20(12):2174-80. Free full text


This is a European cohort study on predictors of spinal injury in adult (≥16 years) major trauma patients, using prospectively collected data of the Trauma Audit and Research Network from 1988 to 2009. Predictors for spinal fractures/dislocations or spinal cord injury were determined using univariate and multivariate logistic regression analysis. 250,584 patients were analysed. 24,000 patients (9.6%) sustained spinal fractures/dislocations alone and 4,489 (1.8%) sustained spinal cord injury with or without fractures/dislocations. Spinal injury patients had a median age of 44.5 years (IQR = 28.8–64.0) and Injury Severity Score of 9 (IQR = 4–17). 64.9% were male. 45% of patients suffered associated injuries to other body regions. Age <45 years (≥45 years OR 0.83–0.94), Glasgow Coma Score (GCS) 3–8 (OR 1.10, 95% CI 1.02–1.19), falls >2 m (OR 4.17, 95% CI 3.98–4.37), sports injuries (OR 2.79, 95% CI 2.41–3.23) and road traffic collisions (RTCs) (OR 1.91, 95% CI 1.83–2.00) were predictors for spinal fractures/dislocations. Age <45 years (≥45 years OR 0.78–0.90), male gender (female OR 0.78, 95% CI 0.72–0.85), GCS <15 (OR 1.36–1.93), associated chest injury (OR 1.10, 95% CI 1.01–1.20), sports injuries (OR 3.98, 95% CI 3.04–5.21), falls >2 m (OR 3.60, 95% CI 3.21–4.04), RTCs (OR 2.20, 95% CI 1.96–2.46) and shooting (OR 1.91, 95% CI 1.21–3.00) were predictors for spinal cord injury. Multilevel injury was found in 10.4% of fractures/dislocations and in 1.3% of cord injury patients. As spinal trauma occurred in >10% of major trauma patients, aggressive evaluation of the spine is warranted, especially, in males, patients <45 years, with a GCS <15, concomitant chest injury and/or dangerous injury mechanisms (falls >2 m, sports injuries, RTCs and shooting). Diagnostic imaging of the whole spine and a diligent search for associated injuries are substantial.

2. Epidemiology and predictors of cervical spine injury in adult major trauma patients: a multicenter cohort study
J Trauma Acute Care Surg. 2012 Apr;72(4):975-81


Patients with cervical spine injuries are a high-risk group, with the highest reported early mortality rate in spinal trauma.

METHODS: This cohort study investigated predictors for cervical spine injury in adult (≥ 16 years) major trauma patients using prospectively collected data of the Trauma Audit and Research Network from 1988 to 2009. Univariate and multivariate logistic regression analyses were used to determine predictors for cervical fractures/dislocations or cord injury.

RESULTS: A total of 250,584 patients were analyzed. Median age was 47.2 years (interquartile range, 29.8-66.0) and Injury Severity Score 9 (interquartile range, 4-11); 60.2% were male. Six thousand eight hundred two patients (2.3%) sustained cervical fractures/dislocations alone. Two thousand sixty-nine (0.8%) sustained cervical cord injury with/without fractures/dislocations; 39.9% of fracture/dislocation and 25.8% of cord injury patients suffered injuries to other body regions. Age ≥ 65 years (odds ratio [OR], 1.45-1.92), males (females OR, 0.91; 95% CI, 0.86-0.96), Glasgow Coma Scale (GCS) score <15 (OR, 1.26-1.30), LeFort facial fractures (OR, 1.29; 95% confidence interval [CI], 1.05-1.59), sports injuries (OR, 3.51; 95% CI, 2.87-4.31), road traffic collisions (OR, 3.24; 95% CI, 3.01-3.49), and falls >2 m (OR, 2.74; 95% CI, 2.53-2.97) were predictive for fractures/dislocations. Age <35 years (OR, 1.25-1.72), males (females OR, 0.59; 95% CI, 0.53-0.65), GCS score <15 (OR, 1.35-1.85), systolic blood pressure <110 mm Hg (OR, 1.16; 95% CI, 1.02-1.31), sports injuries (OR, 4.42; 95% CI, 3.28-5.95), road traffic collisions (OR, 2.58; 95% CI, 2.26-2.94), and falls >2 m (OR, 2.24; 95% CI, 1.94-2.58) were predictors for cord injury.

CONCLUSIONS: 3.5% of patients suffered cervical spine injury. Patients with a lowered GCS or systolic blood pressure, severe facial fractures, dangerous injury mechanism, male gender, and/or age ≥ 35 years are at increased risk. Contrary to common belief, head injury was not predictive for cervical spine involvement.