Front-of-neck airway rescue with impalpable anatomy during a simulated cannot intubate, cannot oxygenate scenario: scalpel–finger–cannula versus scalpel–finger–bougie in a sheep model

Abstract

Background: Front-of-neck airway rescue in a cannot intubate, cannot oxygenate (CICO) scenario with impalpable anatomy is particularly challenging. Several techniques have been described based on a midline vertical neck incision with subsequent finger dissection, followed by either a cannula or scalpel puncture of the now palpated airway. We explored whether the speed of rescue oxygenation differs between these techniques. Methods: In a high-fidelity simulation of a CICO scenario in anaesthetised Merino sheep with impalpable front-of-neck anatomy, 35 consecutive eligible participants undergoing airway training performed scalpelefingerecannula and scalpelefingerebougie in a random order. The primary outcome was time from airway palpation to first oxygen delivery. Data, were analysed with Cox proportional hazards. Results: Scalpelefingerecannula was associated with shorter time to first oxygen delivery on univariate (hazard ratio [HR]¼ 11.37; 95% confidence interval [CI], 5.14e25.13; P<0.001) and multivariate (HR¼8.87; 95% CI, 4.31e18.18; P<0.001) analyses. In the multivariable model, consultant grade was also associated with quicker first oxygen delivery compared with registrar grade (HR¼3.28; 95% CI, 1.36e7.95; P¼0.008). With scalpelefingerecannula, successful oxygen delivery within 3 min of CICO declaration and 2 attempts was more frequent; 97% vs 63%, P<0.001. In analyses of successful cases only, scalpelefingerecannula resulted in earlier improvement in arterial oxygen saturations (e25 s; 95% CI, e35 to e15; P<0.001), but a longer time to first capnography reading (þ89 s; 95% CI, 69 to 110; P<0.001). No major complications occurred in either arm. Conclusions: The scalpelefingerecannula technique was associated with superior oxygen delivery performance during a simulated CICO scenario in sheep with impalpable front-of-neck anatomy.

Success and Time to Oxygen Delivery for Scalpel-Finger-Cannula and Scalpel-Finger-Bougie Front-of-Neck Access: A Randomized Crossover Study With a Simulated “Can’t Intubate, Can’t Oxygenate” Scenario in a Manikin Model With Impalpable Neck Anatomy

“…We chose CICO declaration as the start time to mimic the real-world situation of an unanticipated crisis, during which time is expended as the airway operator works with the team to assemble the necessary equipment for FONA. Our findings are consistent with the results in the only other study comparing the same 2 techniques in simulated impalpable neck anatomy in ovine models, published by Heard et al 10 SFC had a significantly shorter time to first oxygen delivery (hazard ratio, 8.87; 95% CI, 4.31–18.18; P < .001) with higher overall success. Although the time taken from CICO declaration to oxygen delivery was longer in our study, our neck booster was thicker at 5 cm (compared to 3 cm in the above study), and the pliability of synthetic material differs from that of live animal tissue.…”

“…While the fourth National Audit Project (NAP 4) reported a 65% failure rate with the cannula-based technique, 13 our study reported a much lower failure rate with SFC (first-attempt failure, 28%; overall failure, 15%) and higher odds of success compared to SFB. Although consultant grade participants exhibited improved performance in the study by Heard et al, 10 our study found no association between anesthesia experience and time-to-oxygen delivery. A CICO situation requiring an emergency FONA is an extremely rare occurrence; hence, our participants possessed little experience with these techniques.…”

“…Based on the primary outcome of first-attempt success, 60 participants were required to detect a difference of 80% in the SFC group versus 60% in the SFB group, assuming a correlation of 50% between the paired observations, at 90% power and a 5% level of significance. Data for the sample size calculation were based on Heard et al’s 10 publication. Assuming a 10% withdrawal rate, 65 participants were recruited.…”

The Formulation of Cognitive Aids and a Systematic Approach to Emergency Front-of-Neck Access, Following a “Can’t Intubate, Can’t Oxygenate” Crisis in a Patient With Ankylosing Spondylitis

“…The Difficult Airway Society guidelines recommend scalpel-bougie cricothyrotomy, but allude to the use of other valid techniques if additional equipment and comprehensive training are available. 6 Furthermore, while the fourth National Audit Project (NAP 4) reported greater success with surgical techniques over cannula cricothyrotomy, 7 recent animal studies 8,9 have demonstrated the effectiveness of properly performed cannula cricothyrotomy. Notwithstanding this, operators must be mindful of the potential for barotrauma and subcutaneous emphysema associated with inappropriate jet ventilation, which will make subsequent cricothyrotomy attempts difficult or impossible.…”

Cricothyroidotomy in the emergency setting: indications, techniques and outcomes

“…The time difference between the performances of the two techniques is in seconds rather than in minutes [69] and it is likely that this small time factor doesn't have any impact on mortality [1]. In a randomized trial involving sheep models, Heard et al [70] demonstrated a better performance in oxygen delivery using the scalpel-finger-cannula technique as compared to scalpelfinger-bougie, when managing a simulated CICO scenario. In another animal study with porcine models, Umek et al [71] compared the success rate of rescue oxygenation (defined as arterial oxygen saturation > 90% 5 min after the beginning of oxygenation) between surgical scalpel-bougie technique and percutaneous cannula technique.…”