Cut to Air
A “cannot ventilate, cannot intubate” scenario is a rare, high-risk anesthesia event. Cricothyrotomy is the final step, but anesthesia training and maintenance of surgical airway skills is variable. The ability to “cut to air” when one performs a cricothyrotomy may be all that prevents a patient from experiencing anoxic brain injury or death. Forty-three Certified Registered Nurse Anesthetists (CRNAs) performed emergency cricothyrotomies on a simulation manikin. Three techniques were available: (1) cricothyrotomy kit, (2) scalpel and tracheostomy, and (3) scalpel/bougie/endotracheal tube. Technique selection and performance were recorded until successful confirmation of placement was achieved in less than 2 minutes. Confidence levels performing cricothyrotomy were also measured before and after simulation. Most CRNAs (53.5%) selected the cricothyrotomy kit, and all but 1 completed the cricothyrotomy in under 2 minutes. The scalpel/bougie/endotracheal tube combination was the fastest, with an average completion time of 86.6 seconds. The confidence of CRNAs in performing a successful cricothyrotomy in less than 2 minutes was significantly increased (P ≤ .001). Simulating airway skills improved performance, speed, and confidence. Because not all CRNAs have had extensive education in performing surgical airways and practicing these skills, simulation may have additional value in developing and maintaining skills and confidence.
Keywords: Airway management, cannot ventilate/cannot intubate, cricothyrotomy, difficult airway, emergency surgical airway.
A “cannot ventilate, cannot intubate” scenario is a rare, high-risk event that occurs in approximately 1 of 5,000 to 10,000 general anesthetics.1,2 It has been reported that 17% of closed claims outcomes with brain damage and death were due to respiratory events, and 27% of those were due to difficult intubation.3 Furthermore, emergency surgical airways are performed in about 1 of 50,000 general anesthetics.4 Recently, a closed claims analysis by the American Association of Nurse Anesthetists (AANA) identified that 23% of anesthesia-related events leading to death were due to loss of a patient’s airway.4
Time is of the essence when an unconscious patient is not ventilating. Permanent brain damage is detected after 5 minutes or more of anoxia (complete oxygen deprivation) or more than 15 minutes of hypoxia (greatly reduced oxygen supply).5 The severity of neuropsychological injury is dependent on the degree of anoxia or hypoxia experienced, with deficits ranging from mild (mental slowness, memory deficits, memory plus executive function) to serious cognitive impairments, to vegetative states, as well as no observable cognitive function.5
The difficult airway and its management have been topics of interest for a multitude of national and international professional societies.6-9 These societies have published guidelines for difficult airway management based on literature reviews and expert opinions to facilitate the decision-making process during this low-frequency, high-acuity event. The ability to “cut to air” by performing a cricothyrotomy is recommended by every professional organization as the final step in the algorithm for a cannot intubate, cannot ventilate scenario.10 The literature is divided, however, in identifying which emergency cricothyrotomy technique is superior, because each technique has its own shortcomings.10-16
Although there is no gold standard established for emergency cricothyrotomy, there is a consensus on the importance of skill development in advanced airway techniques and proficiency in emergency airway management.13-15 Furthermore, there is a need for rehearsing these skills on a regular basis by all anesthetists, even experienced ones. Regular and repetitive practice is required to retain and reinforce skills that are rarely needed, and repeated training has been shown to attenuate skill loss.13-15
The ideal cricothyrotomy technique would have a high success rate, a short time of execution, and low complication rates; be easy to learn; and have few steps.16 Although some studies claim that surgical cricothyrotomy has faster insertion times and higher success rates at the first attempt, especially by novice practitioners, other studies emphasize the need for effective education, regardless of technique.12-17 Authors of the latter studies claim that if training is adequate and performed on a regular basis, clinicians have an improved success rate and insertion time in a variety of techniques.18-20 A simulation program using fiberoptic intubation demonstrated that experienced nurse anesthetists increased their competence, mastery, and satisfaction using simulation.21 There is literature that suggests greater confidence can lead to better performance.22
Materials and Methods
In a professional development survey administered to a group of Certified Registered Nurse Anesthetists (CRNAs) at a large academic medical center in the mid-Atlantic region, cricothyrotomy was identified as the number 1 critical event the CRNAs wished to learn or review. To address this educational need, an anesthesia “stat” call for a cannot ventilate, cannot intubate simulation scenario was designed. The primary goal was for the CRNA to successfully perform cricothyrotomy in less than 2 minutes. An increase in level of confidence in this low-frequency, high-risk event was the secondary goal. The project was determined to be not human subjects research by the organization’s institutional review board.
Four reviewers—3 CRNAs and the simulation laboratory director—designed the data collection sheet (Figure 1) by identifying key performance points in performing cricothyrotomy. Together, the reviewers timed the first 5 participants to ensure consistency in the documentation of observations and times. Cell phone timers were used to measure the time in seconds. The setting was an emergency department bay in the simulation suite equipped with an adult intubatable manikin (SimMan 3G, Laerdal Medical) lying on a stretcher.
Over a 2 month period, individual CRNAs from a pool of 48 were relieved from clinical duties to participate in the simulation. Each CRNA was randomly selected to participate based on his or her availability, with the goal to educate all staff CRNAs. There was no precourse material or preparation, consistent with real-life airway emergencies. When the CRNA entered the room with the reviewer, he or she was informed that it was an exercise to improve cricothyrotomy skills and that his or her performance would be held confidential, and each was asked if he or she wished to continue. If the answer was affirmative, it was explained that this was a simulated stat emergency airway call in which the CRNA was unable to ventilate or intubate the patient, and the participant was invited to perform a cricothyrotomy on the manikin. There were 3 choices for cricothyrotomy laid out on a Mayo stand: (1) a Melker Cuffed Emergency Cricothyrotomy Catheter Set (Seldinger technique, Cook Medical); (2) a scalpel and size 6 Shiley tracheostomy tube (Covidien, now Medtronic); and (3) a scalpel, bougie, and 6-mm endotracheal tube (Figure 2). Additionally, gloves and personal protective equipment, skin cleaning supplies, a bag-valve-mask, oxygen supply, and ETCO2 detectors were available for participants to complete the exercise.
Cricothyrotomy selection, baseline performance, and then sequential attempts were recorded until time for successful confirmation of placement of less than 2 minutes was achieved. Verbal instruction was offered if the participant faltered or was unable to progress through the procedure. Participants were given time to practice on all methods after the simulation was completed. Time to surgical airway, or “cut to air,” confirmed in less than 2 minutes was the primary endpoint, and measurement of presimulation and postsimulation confidence levels in performing the cricothyrotomy was the secondary endpoint. Demographic data were also collected.
Of the pool of 48 CRNAs, 43 (89%) participated in the simulation. Two CRNAs refused to go to the simulation laboratory, and 3 were on leave at the time of the project. All 43 CRNAs who came to the simulation laboratory responded that they wished to participate in the simulation. Participant demographics were available for 42 participants and are reported in Table 1. Of the 43 CRNAs who participated, most were female (74%, n = 31), were 40 years of age or younger (56%, n = 24), and had greater than 5 years of CRNA experience (58%, n = 24). Regarding prior difficult airway education, 17 CRNAs (42%) reported they had participated in a course, but for the majority, it had been between 2 and 5 years since they had done so (16%). Most commonly, CRNAs had attended airway workshops in their nurse anesthesia programs, through the AANA, their state organizations, or during Advanced Trauma Life Support training. Three CRNAs (7%) reported having had to perform cricothyrotomy on a live patient, 1 of them more than once.
Of the 3 cricothyrotomy equipment options provided, the prepackaged Melker Cuffed Emergency Cricothyrotomy Catheter Set was selected by most (53.5%, n = 23), followed by the scalpel/bougie/6-mm endotracheal tube (39.5%, n = 17) and then the scalpel/6 Shiley tracheostomy method (4.7%, n = 2; Figure 3). During the first attempt (n = 39, 4 aborted), the overall average time to confirmed placement (using a bag-valve-mask device and an ETCO2 detector) was 130 seconds (range = 47-328 seconds), with 21 (53%) of the 39 CRNAs meeting the goal of less than 2 minutes. On the first attempt, those participants choosing the scalpel/bougie/endotracheal tube method confirmed placement in an average of 86.6 seconds (range = 47-222 seconds), whereas those using the prepackaged Melker Cuffed Emergency Cricothyrotomy Catheter Set took an average of 152.8 seconds (range = 92-328 seconds). Those who did not successfully complete the procedure under the goal of 2 minutes were given the opportunity to repeat the simulation, and an additional 14 CRNAs (35%) met the goal on this second attempt. The average time to completion during the second attempt was 82 seconds, with a range of 36 to 172 seconds (n = 25). Three CRNAs took 3 attempts, and 1 took 4 attempts to come in under the 2-minute goal (Table 2). All but 1 staff CRNA met the goal of successfully performing a surgical airway on the manikin in less than 2 minutes; that individual had to leave for patient care reasons.
A secondary goal for this study was to increase the level of confidence the CRNAs reported in their ability to successfully perform a cricothyrotomy in less than 2 minutes. The Wilcoxon signed rank test (IBM SPSS Statistics Version 24, IBM Corp) indicated that the posttest confidence levels were significantly higher than the pretest confidence levels Z = −5.457, P ≤ .001.
Time is of paramount importance in a scenario where a patient cannot be ventilated or intubated. Constrained by time, the individual in charge of accessing, securing, and maintaining the airway must be successful to prevent irreparable damage or death. Given the relative infrequency of a cannot ventilate, cannot intubate scenario, maintenance and readiness training is essential. In addition to helping the CRNAs decrease their cricothyrotomy, or “cut to air,” access time to less than 2 minutes, the overall strategy and design of this effort provided several other beneficial experiences, as well as some unintended consequences.
The design allowed the staff to accurately re-create a surprise emergency airway call, as it would be in real life, by limiting the amount of precourse knowledge to the learners. It also allowed the institution to address and fulfill the demand for practicing cricothyrotomy skills, which was identified as a need in a professional development survey administered to all CRNA staff members. Throughout the project, learners were able to access all the tools used at the institution in the management of this specific patient profile. This prepared them with confidence, functional knowledge, and skills application to manage a cannot ventilate, cannot intubate patient regardless of the tools at their disposal.
It must be acknowledged that simulation is not real life and does not precisely re-create real-life situations. Because this effort focused on a specific provider population and, given the frequency at which providers practice using simulation, there was an assumption made that every participant had some experience with simulation. This, however, was not the case. Some of the learners were not aware of the current capabilities of high-fidelity simulators, and this led to some hesitation and uncertainty. With some adult learners this is a difficult aspect to bypass, and gaining complete buy-in can be difficult, specifically during a project that focuses on a single learner per iteration. One of the learners also expressed that the designed surprise of the simulation felt punitive and objected that his or her performance was graded.
This project has several implications for anesthesia providers. Acknowledging that all CRNAs do not receive uniform difficult airway management during their education is important. Although many CRNAs in this sample had participated in difficult airway management seminars, it had been several years for most. Although 53% of participants were able to successfully “cut to air” on the first attempt, a more frequent review of difficult airway scenarios may be beneficial. Future projects could explore repeating this training at extended intervals and assessing skill retention, techniques of choice, and confidence levels.
1. Nagaro T, Yorozuya T, Sotani M, et al. Survey of patients whose lungs could not be ventilated and whose trachea could not be intubated in university hospitals in Japan. J Anesth. 2003;17(4):232-240. doi:10.1007/s00540-003-0187-3
2. Frerk C, Cook T. Management of the ‘can’t intubate can’t ventilate’ situation and the emergency surgical airway. In: Cook TM, Woodall N, Frerk C, eds. Fourth National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society. Major Complications of Airway Management in the United Kingdom. Report and Findings. London, UK: Royal College of Anaesthetists; 2011:chap 13. https://www.niaa.org.uk/NAP4-Report?newsid=513#pt. Originally accessed December 11, 2018. URL updated January 20, 2020.
3. Steadman J, Catalani B, Sharp C, Cooper L. Life-threatening perioperative anesthetic complications: major issues surrounding perioperative morbidity and mortality. Trauma Surg Acute Care Open. 2017;2(1):e000113. doi:10.1136/tsaco-2017-000113
4. Hranchook AM, Jordan L, Geisz-Everson M, Hirsch M, Matthews RW. A content and thematic analysis of closed claims resulting in death. AANA J. 2018;86(4):311-318.
5. Wilson FC, Harpur J, Watson T, Morrow JI. Adult survivors of severe cerebral hypoxia—case series survey and comparative analysis. NeuroRehabilitation. 2003;18(4):291-298.
6. American Association of Nurse Anesthetists. Difficult airway. In: Clinical practice resources. https://www.aana.com/practice/clinical-practice-resources. Accessed December 15, 2018.
7. DAS guidelines for management of unanticipated difficult intubation in adults 2015. London, UK: Difficult Airway Society. https://das.uk.com/guidelines/das_intubation_guidelines. Accessed December 13, 2018.
8. German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin). About us. https://www.dgai.de/die-dgai/aufgaben-und-ziele/about-us.html. Accessed December 15, 2018.
9. American Society of Anesthesiologists Committee on Standards and Practice Parameters; Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118(2):251-270. doi:10.1097/ALN.0b013e31827773b2
10. Artime CA, Hagberg CA. Is there a gold standard for management of the difficult airway? Anesthesiol Clin. 2015;33(2):233-240. doi:10.1016/j.anclin.2015.02.011
11. Cook TM, Woodall N, Frerk C, eds; Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth. 2011;106(5):617-631. doi:10.1093/bja/aer058
12. Frerk C, Mitchell VS, McNarry AF, et al; Difficult Airway Society Intubation Guidelines Working Group. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth. 2015;115(6):827-848. doi:10.1093/bja/aev371
13. Fikkers BG, van Vugt S, van der Hoeven JG, van den Hoogen FJ, Marres HA. Emergency cricothyrotomy: a randomised crossover trial comparing the wire-guided and catheter-over-needle techniques. Anaesthesia. 2004;59(10):1008-1011. doi:10.1111/j.1365-2044.2004.03794.x
14. Kanji H, Thirsk W, Dong S, et al. Emergency cricothyroidotomy: a randomized crossover trial comparing percutaneous techniques: classic needle first versus ‘incision first’. Acad Emerg Med. 2012; 19(9):E1061-E1067. doi:10.1111/j.1553-2712.2012.01436.x
15. Heymans F, Feigl G, Graber S, Courvoisier DS, Weber KM, Dulguerov P. Emergency cricothyrotomy performed by surgical airway-naive medical personnel: a randomized crossover study in cadavers comparing three commonly used techniques. Anesthesiology. 2016; 125(2):295-303. doi:10.1097/ALN.0000000000001196
16. Chrisman L, King W, Wimble K, Cartwright S, Mohammed KB, Patel B. Surgicric 2: a comparative bench study with two established emergency cricothyroidotomy techniques in a porcine model. Br J Anaesth. 2016;117(2):236-242. doi:10.1093/bja/aew174
17. Hamaekers AE, Henderson JJ. Equipment and strategies for emergency tracheal access in the adult patient. Anaesthesia. 2011;66(suppl 2):65-80. doi:10.1111/j.1365-2044.2011.06936.x
18. Nakstad AR, Bredmose PP, Sandberg M. Comparison of a percutaneous device and the bougie-assisted surgical technique for emergency cricothyrotomy: an experimental study on a porcine model performed by air ambulance anaesthesiologists. Scand J Trauma Resusc Emerg Med. 2013;21(59). doi:10.1186/1757-7241-21-59
19. Schauer SG, Fernandez JR, Roper JL, et al. A randomized cross-over study comparing surgical cricothyrotomy techniques by combat medics using a synthetic cadaver model. Am J Emerg Med. 2018;36(4):651-656. doi:10.1016/j.ajem.2017.11.062
20. Schaumann N, Lorenz V, Schellongowski P, et al. Evaluation of Seldinger technique emergency cricothyroidotomy versus standard surgical cricothyroidotomy in 200 cadavers. Anesthesiology. 2005;102(1):7-11. doi:10.1097/00000542-200501000-00005
21. Moore KC, Smith SJ, Curry DM, Gaspar PM, Nelson EJ. Simulation training for fiber-optic intubations. Clin Simulation Nurs. 2014;10(9):470-475. doi:10.1016/j.ecns.2014.05.007
22. Bommer C, Sullivan S, Campbell K, et al. Pre-simulation orientation for medical trainees: an approach to decrease anxiety and improve confidence and performance. Am J Surg. 2018;215(2):266-271. doi:10.1016/j.amjsurg.2017.09.038
Mary Scott-Herring, DNP, MS, CRNA, is a CRNA manager, Clinical Education and Professional Development, at the University of Maryland Medical Center, Baltimore, Maryland. Email: email@example.com.
Ionela Morosanu, MSN, CRNA, is a staff CRNA at the University of Maryland Medical Center.
Jason Bates, MA, is a training and simulation manager at the R Adams Cowley Shock Trauma Center and the University of Maryland Medical Center.
Bonjo Batoon, MSN, CRNA, is a staff CRNA at the R Adams Cowley Shock Trauma Center, Baltimore, Maryland.
The authors have declared no financial relationships with any commercial entity related to the content of this article. The authors did not discuss off-label use within the article. Disclosure statements are available for viewing upon request.
The authors would like to thank Joshua Blanchette, simulation operator, for his abundance of expertise and patience and the Center for Critical Care and Trauma Education at the R Adams Cowley Shock Trauma Center.
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