Have we been taught all wrong?…A new location of needle decompression?

Posted on December 29, 2012 by petro82

Where do you insert the needle for pneumothorax decompression?

Easy!

Is it time to rethink 2nd intercostal space, mid clavicular line for site of needle decompression?

“2^nd intercostal space (ICS), mid-clavicular line (MCL)” – this has been drilled into all of us since we began training and caring for critically ill patients. Ever since we began as pre-hospital care providers or took our first Advanced Trauma Life Support have we used the 2nd ICS, MCL and assumed it to be optimal.

Well recently some studies have started looking at whether we should consider an alternative location. There is some evidence to suggest that the traditional anterior approach may reduce kinking and in the combat environment, it might be preferred (Beckett A et al. J Trauma 2011). However, if it will never enter into the pleural space then kinking becomes irrelevant. While the utility of needle decompression vs. simple finger thoracostomy followed by chest tube insertion can be debated, in the pre-hospital setting, needle decompression remains within the realm of paramedics and may at times be most practical. Also, unless you’re rapidly prepared to perform a chest tube with sterility in mind, needle decompression may be a better option. Thus, such studies remain important.

A recently published study (from the USC trauma surgeons in Los Angeles who seem to publish everything related to trauma) compared the 2^nd ICS , MCL with the 5^th intercostal space, anterior axillary line (AAL).

CT chest exams of 120 trauma patients were used in the study. Measurements were taken at both sites and compared. Interestingly, the authors stratified patients into 4 BMI categories then analyzed the data based on these groupings.

Results

Overall, the 5^th ICS AAL was a superior site for needle decompression based on chest wall measurement
Chest wall thickness was thicker at the 2^nd ICS MCL compared to the 5^th ICS AAL (by 0.5cm)
As only 16% of patients had chest walls thicker than the standard 5cm needle commonly used. Compared to 42% probable failures if placed at the 2^nd ICS MCL.
Based on BMI stratification, needle decompression at the 5^th ICS AAL would be possible for all but the highest BMI while at the 2^nd ICS MCL would likely fail except in the lowest group

Take home message – given this was not a clinical study (only based on CT scans) it’s not quite practice changing. We don’t know the potential risks of cardiac injury using the 5^th ICS AAL or whether it can be feasibly performed without kinking. However, this technique could be considered if the 2^nd ICS MCL fails, especially in high BMI patients and clearly any benefits outweigh the risks – for instance if the patient has already arrested.

STUDY ABSTRACT

Inaba K et al Radiologic evaluation of alternative sites for needle decompression of tension pneumothorax. Arch Surg 2012;147:813-8

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

Oxygen physiology and pulse oximetry lag podcast

Posted on December 20, 2012 by Scott Orman

This podcast, from the Scott Weingart’s superb emcrit.org site, discusses the lag between oxygen delivery commencing following RSI and the rise in saturations on the patient monitor. It is directly relevant to the prehospital setting, given that a colder environment and a shocked/underresuscitated patient results in a longer pulse oximetry lag. The discussion also makes note of several cases where a (probably) successfully placed ETT was removed in the prehospital setting due to pulse oximetry lag.

The emcrit show notes are here

The podcast is here

NAP4 and its implications for prehospital airway management

Posted on December 6, 2012 by Scott Orman

In 2011 the U.K. Royal College of Anaesthetists and The Difficult Airway Society released a report called NAP4 – the 4th national audit of major complications of airway management.

Full text of NAP4 report

The report covered airway complications that occurred in anaesthesia, ICU, and ED settings (approximately 20000 in total). Every reported complication of airway management was analysed for causes and learning points.

The findings relating to ED complications have direct implications for prehospital airway management.

‘Take-home’ messages relating to ED airway management:

in the event of an airway complication (most commonly failed RSI), patients were more likely to die in ED or ICU than OR
at-risk patients were often not identified prior to the attempt at airway management
waveform quantitative capnography should be the standard of care for EVERY intubation
situations where the capnography reading was zero (indicating misplaced or completely obstructed ETT) were incorrectly attributed to cardiac arrest (CPR always generates SOME CO2)
complications arose when there was a ‘failure to plan for failure’
obesity was a major risk factor for airway complications

and, most importantly:

in the event of a surgical airway being needed, surgical cricothyroidotomy was almost universally successful, while needle cricothyroidotomy had a failure rate of up to 60%
the success of surgical cricothyroidotomy included those where ED doctors (not surgeons) were the ones performing the procedure

Here is an excellent podcast – it is an interview by Cliff Reid of Jonathan Benger, a Professor of Emergency Medicine and one of the authors of the NAP 4 study (sourced from emcrit.org) regarding the implications of NAP4 for emergency department airway management.

So what are the implications for our HEMS service?

The most relevant findings for us form NAP4 are the findings relating to airway complications in ED, more so than anaesthesia or ICU. Patients who we would intubate pre-hospital are those who, if prehospital intubation were not available, would be intubated shortly after arrival in ED. The majority of our doctors are ED-trained, and are most familiar with ED airway management (translation: simple, fast, relatively low-tech, with the fairly standardised approach for the majority of our patients)

Bringing ED airway management to the prehospital arena has its challenges. The patients are more undifferentiated, comparatively under-resuscitated, and there may not have been enough time to get a sense of their ‘trajectory’.Environmental factors (light, weather, physical access to patient) will have a huge impact on the execution of airway intervention. We have a lot less equipment – no Glidescope, less rescue devices, and no telephone to call for an anaesthetist and a tech with a trolley full of difficult airway equipment. We may have team members (relatively junior ambulance staff, for example) who have much less experience with RSI than ED nurses who are often part of our RSI team.

Doing the basics right therefore becomes even MORE important:

equipment must be effective, functional, and familiar to us through training
there must be a ‘shared mental model’ – including a plan for success and a plan for failure – which must be vocalised for every patient with all team members understanding their role
we must actively consider patient specific elements that will affect the plan for success and the plan for failure (anatomy, injury, obesity etc)
we must be as prepared as possible – if the situation allows, taking several extra minutes to optimise positioning, place nasal cannulae for apnoeic ventilation etc may be crucial
we can overcome the disorienting effect of unfamiliar/unfriendly environments by using our RSI checklist – this was we are unlikely to forget something crucial (like capnography)
there must be a relatively ‘hands off’ team member whose task is to maintain situational awareness – in particular to initiate the ‘plan for failure’ should it become necessary
in the event of ‘can’t intubate, can’t ventilate‘, a surgical cricothyroidotomy should probably be our ‘go-to’ surgical airway of choice. If needle cricothyroidotomy has a failure rate of up to 60% in a hospital setting, it is hard to imagine how it could fare better in the prehospital arena. Of course there may be exceptions to this (difficult neck anatomy etc)

More commentary on the results and implications of NAP4 can be found here (British Journal of Anaesthesia, section of report relevant to ED and ICU) and here (from Cliff Reid)

“The best lecture on airway management – ever?”

Posted on December 5, 2012 by Scott Orman

In the continuing aucklandhems.com theme of not reinventing the wheel, here is a superb video podcast of a lecture about airway management by Dr Richard Levitan – emergency physician and airway guru.

It focuses on laryngoscopy, including techniques for improving your view, bimanual laryngoscopy, positioning and head elevation, apnoeic oxygenation, avoiding common pitfalls, and understanding the dynamic elements of airway anatomy.

In our prehospital setting, good laryngoscopy technique (or, as Dr Levitan puts it, the sequence of epiglottoscopy —> laryngoscopy —> tube delivery) is the cornerstone technical skill of airway management – not a Glidescope in sight!

This podcast was sourced from Scott Weingart’s emcrit.org

The slide set for the talk is here

The video podcast is here

The landmark paper Preoxygenation and Prevention of Desaturation During Emergency Airway Management (by Drs Levitan and Weingart) is here

Auckland HEMS

Unofficial site for prehospital care providers of the Auckland HEMS service

Category Archives: Procedures