Page 54 - JSOM Winter 2024

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contraindicated for the following conditions: cardiac arrest, hy- medics. The Control-Cric was superior to the ETT in speed
povolemia, increased intracranial pressure, and right heart fail- and success rate. The Control-Cric (often referred to by the
ure. Caution must be exercised with patients with obstructive stylet component name Cric-Key), was subsequently approved
lung disease, COPD, and asthma when using PEEP. These pa- in 2015 as the recommended TCCC cricothyrotomy device.
tients have a prolonged expiratory phase, and therefore have dif- Since Mabry’s 2015 study, there have been several published
ficulty exhaling the full volume before the ventilator delivers the papers that have compared the Control-Cric to modern and
next breath. As a result, there is an increase in the intrinsic PEEP, purpose-built cricothyrotomy equipment. Further analysis
also known as auto-PEEP. The hyperinflation is progressive of commercial devices and a high procurement cost of the
and worsens with each tidal volume delivered. It leads to over- Control-Cric drove a re-evaluation of preferred cricothyrot-
distention of the alveoli and increases the risk for barotrauma. 62 omy equipment and procedure technique.
While there is no available research on prehospital dispos- A 2019 randomized assessment of three cricothyrotomy devices
able PEEP valve use in the adult population, there is a single compared the Control-Cric to a commercial competitor and a
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study on one-time use valves on neonates. The results of this bougie-assisted ETT technique. Using 25 Navy Corpsmen,
study demonstrate that single-use PEEP valves do not reli- 15 minutes of training for each device, and a training man-
ably deliver the requested set amount of PEEP. It was found nequin, the Control-Cric was not recommended, and ranked
that when the PEEP device was set to 5cmH O, an average of last in terms of time to insertion. When asked, “If you could
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only 3.4cmH O of PEEP was delivered to the patient. Simi- choose one kit, which would it be?” no participants preferred
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larly, when the PEEP was set to 10cmH O, an average of only the Control-Cric; significantly lower than the competitor kit
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6.1cmH2O was delivered. 63 (58%) or bougie-assisted (42%) results. A similar randomized
study prepared by Schauer et al. compared the Control-Cric to
In conclusion, while the National Association of EMS Phy- a commercial competitor and open surgical technique using a
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sicians recommends prehospital PEEP, non-ARDS PEEP pa- tracheostomy-style tube. Using U.S. Army combat medics, the
tients have shown no mortality reduction, ER/ICU length of Control-Cric failed to outperform in any category, performing
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stay reduction, or improvement in hypoxemia. Additionally, second or third out of 3 devices in each of the focus areas.
two-provider BVM resuscitation is likely required in order Level of Evidence: B-NR and C-LD (Nonrandomized and Lim-
to strictly maintain a mask seal for PEEP effectiveness, con- ited Data)
straining limited manpower resources. Due to the lack of ALI
and ARDS development for point-of-injury (POI) patients in What cricothyrotomy technique(s) are superior?
the battlefield setting, lack of sophisticated ventilatory tools,
concern of intrathoracic pressure at higher PEEP settings, A systematic review of cricothyrotomy techniques (1,405
manpower requirements, and overall insufficient evidence to references/108 full-text articles/24 studies) identified a large
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support a decrease in mortality risk, current evidence does not volume of methods (17); none of which demonstrated clear
support routine use of PEEP within the TCCC provider pop- superiority. Mabry et al. categorized and described popular
ulation at this time. Lengthier patient care timelines requiring cricothyrotomy techniques into these 4 different methods: 3
ventilation devices found in Prolonged Casualty Care (PCC) or
CASEVAC/MEDEVAC settings may influence reconsideration 1) Open surgical technique: Using typical surgical tools with a
of PEEP for certain patients. We recommend future studies to vert or horizontal incision
evaluate PEEP in the battlefield trauma patient population. 2) Bougie aided: Modifying the open surgical utilizing a bou-
Level of Evidence: Level C-LD (Limited Data) gie after the incision
3) Tube Over a Needle: Using a percutaneous device, overrid-
Why is the cricothyrotomy procedure considered ing the requirement to incise
critical, and what are the challenges associated 4) Wire guided: Inserting a needle, then a wire-based bougie
with it?
As noted by Langvad et al., there are multiple variations to
As a last resort procedure for most airway management proto- each of these generalized techniques and examining head-to-
cols, it is critical that providers perform successful cricothyrot- head studies can be difficult due to the built-in disparities of
omy access. Military medics perform cricothyrotomy at a rate each. An example of this is that some open surgical techniques
that is nearly double that of their civilian counterparts, likely call for the use of a Trousseau dilator, while other variations,
due to injury severity and standing guidelines. Civilian EMS such as the Rapid Four Step Technique (RFST), eliminate the
sees a preponderance of motor vehicle collisions for trauma but midline incision and remove the dilator as required equip-
use cricothyrotomy as a last resort airway in lieu of failed ETI ment; additionally, each of these techniques may include dif-
or EGA attempts. The failure rate for military medics is three to ferent forms of cannulas.
five times higher than civilian rates. It is imperative that an in-
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crease in effective training be required for this critical task and Mabry et al. recommended the open surgical technique in
that reliable confirmation tools or procedures are available. awake patients. The technique “will maximize anatomic ex-
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Level of Evidence: B-NR and C-LD (Nonrandomized and Lim- posure, minimize bleeding, and allow for extension of the inci-
ited Data) sion at either end if the initial incision is not optimally placed.”
• The surgical technique was found superior to the Melker
Why is the Control­Cric no longer the preferred and Quicktrach II device in a study by Heymans et al. in-
cricothyrotomy tool in the CoTCCC guidelines? volving 20 medical students and cadavers. The success
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In 2015 Mabry et al. published a performance comparison rates were 95%, 55%, and 50% for surgical cricothyrot-
of the Control-Cric versus an ETT canula used by U.S. Army omy, Quicktrach, and Melker, respectively (P=.025).

52 | JSOM Volume 24, Edition 4 / Winter 2024