An ALS unit is dispatched for an adult patient complaining of severe painful swallowing and difficulty breathing. Upon arrival the patient is acutely decompensating with increasing respiratory effort and diminished color. Supplemental oxygen isn’t providing adequate perfusion.
Due to the patient’s rapidly deteriorating condition, the decision is made to intubate. As the laryngoscope is slid beyond the oral cavity, severe epiglottic swelling is visualized.
After one intubation attempt the swelling worsens. At this point, endotracheal intubation is not feasible. With no options left, the paramedic resorts to reaching for the cricothyrotomy kit.
Sweat beads on the paramedic’s brow as he questions his ability to perform the procedure. He’s seen very few performed and has never actually done one himself, but this is the only option.
With trepidation, the cricothyrotomy kit is opened and the paramedic finds two choices: needle or surgical. He’s unsure what method to choose. Without further evidence to base the decision off of, the paramedic selects the needle technique as it appears less invasive.
Was this the right decision?
In “cannot intubate, cannot ventilate” scenarios, prehospital providers are left with few options. The most current algorithms published by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway (United States) and the Difficult Airway Society (United Kingdom) indicate cricothyrotomy as a final effort to secure an airway.1,2 Cricothyrotomy is appropriate, as it’s been shown to be more effective than continued, generally unsuccessful, attempts at endotracheal intubation3.
Prehospital cricothyrotomies are exceedingly rare due to their use as a procedure of last resort. Large observational studies demonstrate that cricothyrotomies are performed in approximately 1% of all prehospital patients requiring advanced airway management.4,5
As a result of the low frequency of cricothyrotomies, it’s common for providers to express hesitancy with regards to the advanced technique.6 This hesitancy is well-founded as one study showed that after just three months post-training, cricothyrotomy skills decline significantly.7
This uncertainty is further complicated by the fact that two accepted techniques exist to carry out the procedure: needle and surgical. Commercially available kits will not be discussed as these kits generally employ variations of needle and surgical techniques.
Needle: The needle technique is accomplished by inserting a 12- to 14-gauge cannula through the cricothyroid membrane and into the trachea.8 Ventilation occurs through the cannula, but is only effective with high-pressure jet ventilation.9 This technique is used as a temporary measure intended to provide ventilation for only 15—20 minutes.10
Surgical: The surgical technique is accomplished by using a scalpel to cut through the cricothyroid membrane, allowing a cuffed tube to be inserted into the trachea for ventilation.11
The largest meta-analysis to date, inclusive of 512 adult cricothyrotomies, found that surgical cricothyrotomies (SCRICs) were significantly more successful than needle cricothyrotomies (NCRICs). SCRICS had a success rate of 90.5% (84.8—94.2) compared to a success rate of 65.8% (42.3—83.59) for NCRICS. Furthermore, the authors found SCRICs had similar success rates to the King Laryngeal Tube airway. Due to the significant and conclusive findings, the authors recommend that SCRICs be preferred over NCRICs for adult patients.12
Since this meta-analysis, other studies have reached similar conclusions regarding SCRIC’s superiority. One randomized prospective study looked at cricothyrotomy performed on cadavers, and the authors found that surgical techniques were nearly twice as effective and resulted in far fewer potentially life-threatening complications compared to other needle-based methods.13
As a result of the data from these studies and others, the Resuscitation Council (which plays a similar role in the UK to that of the American Heart Association) published evidenced-based guidance surrounding cricothyrotomy in their 2015 prehospital resuscitation guidelines. The adult guidelines endorse SCRICs and explicitly state that “needle cricothyroidotomy is generally of limited effectiveness.”14
The endorsement of SCRICs over NCRICs is significant, as the Resuscitation Council uses systematic and validated methods to review evidence and evaluate the benefits and harms of treatment modalities when creating its guidelines. The systematic accrual, evaluation and application of new evidence ensures that clinical care is being driven by the best available data.
Cricothyrotomies Performed Across the U.S.
As state EMS agencies make progress towards integrating evidence-based guidance into clinical practice, it’s critical for this process to be evaluated. Cricothyrotomy is an example of a practice that has a rapidly evolving evidence base, signaling the need for changes in clinical practice.
In evaluating whether state EMS agencies are remaining abreast of the best evidence, all available statewide adult cricothyrotomy protocols (inclusive of both mandatory and model protocols) were gathered and analyzed. Only the most recently updated protocols available online were accessed. At the time of the analysis (in 2018), the majority of protocols were published within that year, but some are older.
After analyzing the included states, it was found that three categories of cricothyrotomy protocols existed.15 These categories encompass: 1) states allowing both SCRIC and NCRIC, but not specifying a preference; 2) states specifying an SCRIC preference; and 3) states only allowing NCRIC. (See Figure 1.)
Note that category 1 is inclusive of states which don’t specify an exact method (needle or surgical), leaves the decision to local medical directors, or doesn’t specify a preference between commercial kits, SCRICS or NCRICS. Category 2 is inclusive of states only allowing SCRIC and of states allowing SCRIC, in addition to commercial kits, which is a surgical-based technique.
To best illustrate how this works at the individual state level, a state from each category is discussed in more detail below:
- No Preference: In Maryland, SCRICs and NCRICs are both listed under the “Protocol for Cricothyroidotomy” with no reference regarding when to utilize which.
- SCRIC Preference: Utah lists “Open Surgical Cricothyrotomy” as the only option for adult patients.
- NCRIC Only: Massachusetts has no mention of SCRICS within their protocols, but includes a step-by-step guide detailing NCRICs.
The analysis showed that all states with available statewide guidance excluding Iowa allowed at least one cricothyrotomy technique. Only 30% of states indicated a preference towards SCRIC.15 It’s important to remember that many states don’t publish statewide protocols (mandatory or model). These states were not included in the analysis.
Compliance with Best Available Evidence
To evaluate whether states were complying with the best available evidence regarding cricothyrotomy, evidence-based guidelines (EBG) were taken from the UK Resuscitation Council’s 2015 guidelines for prehospital resuscitation. The guidelines were condensed into two core points: 1) Providers should be allowed to perform SCRICs; and 2) SCRICs should be preferred over NCRICs. This condensed evidence-based guidance was then compared to each available state’s cricothyrotomy protocol to see if that protocol conformed with best evidence.
Full compliance was established by meeting all evidence points. Partial compliance was established by meeting at least one of the evidence points. Complete lack of compliance was achieved by states meeting none of the criteria.
It was found that 30% of all available protocols were fully compliant with the best available evidence, 52% were partially complaint, and 18% were not compliant at all.15
According to the best available evidence, the paramedic in the initial scenario would have had a higher chance of success and lower likelihood of complications had they elected for the more definitive surgical technique. Even though substantial data supports the SCRIC technique, many paramedics are completely unaware of this body of evidence. This is especially problematic as the majority of analyzed states fail to provide clear evidence-based instructions within their protocols to guide cricothyrotomies.
This lack of instruction leaves paramedics with little information to guide their clinical decision making. Even more troublesome is the fact that some states (e.g., Alabama, Iowa, West Virginia, New Jersey, Massachusetts and Washington, DC) don’t allow the SCRIC technique at all.
Aside from states that don’t allow SCRICs, states that provide unclear guidance without preferring one cricothyrotomy technique over the other are just as problematic. One study, which assessed the usefulness of providing clinicians with evidence in making point-of-care decisions, found that for the majority of clinicians, clear, accessible and concise evidence beneficially affected clinical decision-making.16 The absence of clear evidence within protocols disempowers practitioners in their decision between cricothyrotomy techniques and exposes patients to less effective procedures.
Compounding the issue of unclear guidance, many paramedics find they are ill-equipped to perform cricothyrotomies. One study revealed that 73% of paramedics didn’t feel adequately trained when it came to cricothyrotomy. The same study showed that 40% of paramedics felt they would fail when performing a cricothyrotomy.17 This lack of confidence combined with deficiencies in clear guidance is troublesome as it could alter or significantly delay appropriate care.
“Cannot intubate, cannot ventilate” scenarios are the epitome of situations where seconds matter and mistakes can be fatal. This urgency is compounded by lack of experience and uncertainty. Equipping paramedics with the most up to date evidence is crucial in all of EMS, but is especially pertinent to scenarios where seconds can make the difference between a good and poor outcome.
Conclusive data and internationally reputable evidence-based guidance exist to support the use of SCRICs over NCRICs for prehospital emergency airway procedures, yet conformity to evidence-based guidance relating to cricothyrotomy is low. A small minority of states list a preference towards SCRIC. This is concerning as NCRICs have comparatively higher rates of failure and accompanying complications.
Further exacerbating the issue, many states, regardless of preference, allow providers to use NCRIC at their discretion. The inconsistencies between evidence-based guidance and state protocols indicate that inconsistencies in cricothyrotomy techniques are an issue that states must revisit as they continually update their protocols.
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