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Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma patients
YAJEM-56973; No of Pages 6 American Journal of Emergency Medicine xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma patients☆ Matthew C. Hernandez, MD a,⁎, Johnathon M. Aho, MD a, Martin D. Zielinski, MD a, Scott P. Zietlow, MD a, Brian D. Kim, MD a, David S. Morris, MD b a b
Division of Trauma Critical Care and General Surgery, Department of Surgery, Mayo Clinic, Rochester, MN, USA Division of General Surgery, Trauma, and Critical Care, Intermountain Medical Center, Murray, UT, USA
a r t i c l e
i n f o
Article history: Received 27 June 2017 Received in revised form 9 September 2017 Accepted 14 September 2017 Available online xxxx Keywords: Prehospital Airway Supraglottic airway Trauma Tracheostomy
a b s t r a c t Background: Prehospital airway management increasingly involves supraglottic airway insertion and a paucity of data evaluates outcomes in trauma populations. We aim to describe definitive airway management in traumatically injured patients who necessitated prehospital supraglottic airway insertion. Methods: We performed a single institution retrospective review of multisystem injured patients (≥15 years) that received prehospital supraglottic airway insertion during 2009 to 2016. Baseline demographics, number and type of: supraglottic airway insertion attempts, definitive airway and complications were recorded. Primary outcome was need for tracheostomy. Univariate and multivariable statistics were performed. Results: 56 patients met inclusion criteria and were reviewed, 78% were male. Median age [IQR] was 36 [24–56] years. Injuries comprised blunt (94%), penetrating (4%) and burns (2%). Median ISS was 26 [22–41]. Median number of prehospital endotracheal intubation (PETI) attempts was 2 [1-3]. Definitive airway management included: (n = 20, 36%, tracheostomy), (n = 10, 18%, direct laryngoscopy), (n = 6, 11%, bougie), (n = 9, 15%, Glidescope), (n = 11, 20%, bronchoscopic assistance). 24-hour mortality was 41%. Increasing number of PETI was associated with increasing facial injury. On regression, increasing cervical and facial injury patterns as well as number of PETI were associated with definitive airway control via surgical tracheostomy. Conclusions: After supraglottic airway insertion, operative or non-operative approaches can be utilized to obtain a definitive airway. Patients with increased craniofacial injuries have an increased risk for airway complications and need for tracheostomy. We used these factors to generate an evidence based algorithm that requires prospective validation. Level of evidence: Level IV – Retrospective study. Study type: Retrospective single institution study. © 2017 Elsevier Inc. All rights reserved.
1. Introduction A functional and patent airway during prehospital resuscitation is a critical consideration of trauma resuscitation [1]. Several risk factors confound prehospital airway control such as obesity and craniofacial trauma [2]. Supraglottic devices may be utilized for the difficult airway
☆ Author contribution: Study design was developed by Matthew Hernandez, Johnathon Aho, David Morris, and Martin Zielinski. Data generation was performed by Matthew Hernandez. Data analysis and interpretation was performed by Matthew Hernandez, Johnathon Aho, Martin Zielinski, Scott Zietlow, Brian Kim, and David Morris. Manuscript writing was performed by Matthew Hernandez, Johnathon Aho, Scott Zietlow, Brian Kim, David Morris and Martin Zielinski. ⁎ Corresponding author at: Division of Trauma Critical Care and General Surgery, Department of Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. E-mail addresses: [email protected] (M.C. Hernandez), [email protected] (J.M. Aho), [email protected] (M.D. Zielinski), [email protected] (B.D. Kim), [email protected] (D.S. Morris).
[1,3-5]. After supraglottic device insertion, methods to secure a definitive airway include direct laryngoscopy, blind tube exchange or fiberoptic guidance [6]. In cardiac arrest, supraglottic airway exchange may not be urgent as the primary focus is restoration of spontaneous circulation [7]. Conversely, the trauma resuscitation focuses on constant airway assessment to gauge patency and adequate ventilation. This is the unique difference; maintenance of airway control and prevention of dysoxia while systematically triaging injury care by severity whereas medical resuscitations aim to restore and maintain cardiac flow. In the prehospital setting, supraglottic devices provide initial airway control with ease of insertion [8-10]. These advancements come at the expense of potential complications. Morbidity such as gastric distension, tube malposition and oropharyngeal edema resulting abrupt airway occlusion can occur [5,11-15]. Management algorithms exist to secure a definitive airway after supraglottic device insertion; however, these recommendations are from variable populations [16-19]. For trauma patients necessitating prehospital supraglottic airways, there is a
http://dx.doi.org/10.1016/j.ajem.2017.09.028 0735-6757/© 2017 Elsevier Inc. All rights reserved.
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
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M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
lack of evidence to adequately address definitive airway management. Therefore, we aimed to determine which definitive airway techniques were utilized after prehospital supraglottic device insertion in multisystem injured patients hypothesizing that patients with increased prehospital airway complications and craniofacial injury patterns would require advanced airway control, including surgical tracheostomy.
with 95% confidence intervals (CI). Data was analyzed with JMP (SAS Institute, Inc. Cary NC). We utilized GraphPad Prism (GraphPad Software, Inc. La Jolla CA) for all visual graphics.
2. Methods
The study cohort consisted of 56 patients with multisystem trauma and supraglottic airway insertion. The median [IQR] ISS was 26 [22– 41] and 78% of patients were male. The mean (± SD) age was 39.6 (± 21.2) years. Most patients (72%) were transported via rotor wing and median [IQR] transport time was 20 [13 − 33] minutes. Mean (± SD) body mass index (BMI) was 29.2 (± 6.6). The median [IQR] head, neck and facial abbreviated injury scores (AIS) were: head 4 [35], neck 2 [0–3], face 1 [0–2] respectively, Table 1. Mechanisms of injury included blunt (n = 53, 94%), penetrating (n = 2, 4%), and burn (n = 1, 2%).
2.1. Patient cohort From 2009 to 2016, we performed a single center retrospective study examining patients N15 years old with multisystem trauma defined as an Injury Severity Score of ≥9 that necessitated prehospital insertion of a supraglottic airway (patients receiving only a King Airway Device, King LT-D, Noblesville, IN). Patients were identified from the Mayo Clinic Trauma Center registry. Institutional review board approval was obtained prior to data review. Patients that refused research consent, received prehospital endotracheal tube intubation (PETI), were pregnant, or without multisystem trauma were excluded. 2.2. Prehospital airway institutional protocol Patients were transported by a critical care trained rotor wing team or ground transport. Injured patients that require advanced prehospital airway management meet criteria for our highest level trauma activation, which includes Emergency Medicine, Surgery, and Anesthesia providers to be present at patient arrival. Each prehospital airway intervention at our facility is reviewed in detail by the directors of Medical Transportation, Emergency Medicine, Trauma Surgery, and Anesthesia divisions. A prehospital advanced airway control algorithm (Fig. 1) has been defined and implemented by this group to standardize difficult airway management in the prehospital setting. This algorithm is designed for use after clearly defined “failure” of standard prehospital endotracheal intubation (PETI) attempts and after non-invasive ventilation is determined to be inadequate. 2.3. Outcomes and predictors The primary outcome for this study was need for tracheostomy. If a tracheostomy was not performed and instead an endotracheal tube exchange (ETT) was performed, the method of ETT was recorded (direct laryngoscopy, bougie, Glidescope, bronchoscopic assistance). Patient demographics, transportation method and duration, traumatic mechanism, trauma severity (ISS and abbreviated injury scores (AIS)), admission vital signs (heart rate, respiratory rate, systolic and diastolic blood pressure and oxygen saturation), Glasgow Coma Score (GCS), 24 h and overall mortality, frequency and type of prehospital airway complications, and number of PETI, and durations of intensive care, mechanical ventilation or overall hospital stay were abstracted from the electronic record. Mortality was defined according to definitions reported previously [20]. 2.4. Statistical analyses Summary statistical and univariate analyses were performed. Continuous variables were described using means with standard deviations (SD) if normally distributed and medians with inter-quartile ranges [IQR] for non-normally distributed data and two tailed t-tests were performed between definitive airway techniques, endotracheal tube exchange (ETT) versus surgical tracheostomy. Categorical variables were summarized as proportions, and differences were evaluated using chisquare analysis. All p-values were considered significant at p b 0.05. Clinical and statistically significant variables were evaluated to assess for risk factors for 24-h mortality using nominal logistic regression
3. Results 3.1. Baseline demographics
3.2. Prehospital airway characteristics In the prehospital setting, supraglottic device indications included failed PETI (n = 56, 100%). The median [IQR] attempts at PETI were 2 [2–3]. The number of failed PETI attempts increased in patients with increased craniofacial injury patterns Fig. 2. At arrival, all patients had a patent and functional airway provided by the supraglottic device. During prehospital resuscitation, there were 35 (63%) complications including significant laryngeal or oropharyngeal edema preventing PETI (n = 22, 63%) and supraglottic airway dislodgement (n = 13, 37%). 3.3. In hospital outcomes and definitive airway management Techniques for in hospital definitive airway included ETT (n = 36; 64%) or surgical tracheostomy (n = 20; 36%). For patients managed with ETT, 50% (n = 18) were performed in the emergency room and 50% (n = 18) were performed in the operating room. Table 2 compares outcomes and secondary predictors by definitive airway and this demonstrates the association of increased craniofacial injury patterns with a need for surgical tracheostomy. In patients who required definitive airway with a surgical tracheostomy, compared to ETT, there was an increased median facial AIS (4 [3-4] versus 1 [0–2], p b 0.0001). There was no statistically significant difference in median head AIS (4 [2–5] versus 4 [2–5]) injury severity but there was an approach to statistical significance and likely clinical significance in patients with increased median cervical AIS (2 [0–3] versus 1 [0–2], p = 0.08). Multivariable analysis demonstrated that the following factors were independently associated with need for surgical tracheostomy compared to ETT in patients with a prehospital supraglottic rescue airway: Facial AIS ≥3, cervical AIS ≥ 3, and number of PETI attempts, Table 3. During definitive airway management (open tracheostomy or endotracheal tube exchange (ETT)), the median [IQR] oxygen saturation nadir was significantly lower in patients that received ETT compared to open tracheostomy, (84% [75–89] versus 92% [88–94], p = 0.007). This difference disappeared within 10 min of definitive airway management completion (99 [96–99] versus 99 [96–100], p = 0.8). There were no long-term complications from surgical tracheostomy or ETT during follow up, median 13 [1–37] months. There were 23 patients that expired. Causes for mortality included myocardial infarction (n = 3), pulmonary contusion (n = 4), and tension pneumothorax (n = 3), traumatic brain injury (n = 5), and hemorrhagic shock (n = 8). No deaths were related to inpatient airway complications. There was less overall mortality in those receiving tracheostomy compared to those undergoing ETT (n = 8, (24%) versus n = 27, (77%), p = 0.01). With respect to 24-hour mortality, a more pronounced difference existed between patients undergoing tracheostomy compared to ETT (n = 3, (13%) versus n = 20, (87%), p = 0.004).
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
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Fig. 1. Institutional clinic prehospital transport airway management algorithm (after first failed attempt).
4. Discussion This analysis underscores several challenges, prehospital airway complications, and important clinical outcomes in patients receiving
supraglottic airway insertion. We demonstrate that after prehospital supraglottic airway insertion in polytrauma, definitive airway management via surgical tracheostomy was associated with severe craniofacial injury patterns and multiple PETI attempts. Moreover, we
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
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M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
Table 1 Patient characteristics comparing definitive airway technique Characteristic
Overall (n = 56) No. (%)
Endotracheal tube exchange (ETT) (n = 36) No. (%)
Tracheostomy (n = 20) No. (%)
p value
Baseline demographics Age, median [IQR] Male BMI, median [IQR]
36 [24–56] 44 (79) 29 [24–33]
33 [21–55] 16 (80) 31 [2–34]
41 [26–59] 28 (78) 28 [24–33]
0.6 0.7 0.6
Prehospital metrics Prehospital transport time, median [IQR]
25 [15–33]
25 [18–39]
21 [12−32]
0.2
Patient physiology Heart rate, median [IQR] Respiratory rate, median [IQR] Oxygen saturation, median [IQR] Systolic blood pressure, median [IQR] Diastolic blood pressure, median [IQR]
110 [96–116] 22 [17–26] 96 [87–99] 104 [80–123] 60 [50–80]
112 [101–117] 24 [20–27] 87 [66–94] 106 [72–128] 64 [50–81]
110 [81–116] 21 [16–37] 84 [68–96] 103 [84–122] 61 [50–80]
0.3 0.1 0.8 0.7 0.8
Predictors ISS, median [IQR]
26 [22–41]
35 21–43]
26 [22–38]
0.3
BMI: body mass index, ISS: injury severity score, IQR: interquartile range, ETT: endotracheal tube exchange.
demonstrated that those who received surgical tracheostomy as a definitive airway had minimal oxygen saturation fluctuation compared to those with endotracheal tube exchange (ETT). This analysis provides preliminary data for the role of adjunct airways, granular complication data, and initial implications for definitive airway management in adult trauma patients. Airway assessment and control is a primary objective during trauma resuscitation. For supraglottic airways in trauma, minimal evidence exists to guide definitive airway management (16). Subramanian et al. reported that for patients presenting with supraglottic airways, few had associated trauma, and in those patients the definitive airway was managed using a surgical tracheostomy in the majority (5). The present study is comprised entirely of multisystem trauma patients. Our analysis provides a trauma only cohort that analyzes subsequent definitive airway management. Patients with multisystem trauma pose a significant challenge for airway control. In the prehospital setting, two priorities are of equal value 1) minimization of airway iatrogenic injury and 2) rapid transport to definitive care. Supraglottic devices, such as the King LT™, are one method to provide a temporary airway. Since these devices are increasingly utilized, a comprehensive analysis of the indications, complications, and subsequent definitive airway management has not been adequately provided. We demonstrated that for patients with increasing craniofacial trauma, definitive airway management after supraglottic airway insertion is associated with tracheostomy compared to ETT. This finding echoes other work which has advocated for the use of tracheostomy in the management of definitive airways after supraglottic airway device insertion [16]. Definitive airway management requires rapid assessment and an actionable plan amidst the multiple priorities that occur in trauma resuscitation. The association of increasing number of PETI attempts and
Fig. 2. Increased facial trauma, (AIS grade), associated with increased prehospital endotracheal intubation. * denotes p b 0.05.
craniofacial injury patterns with surgical tracheostomy justifies our proposed definitive airway algorithm, as shown in Fig. 3. Patients who meet criteria would have, at the minimum, definitive airway evaluation in the operative room as opposed to trauma resuscitation bay. Application of these criteria may prevent premature attempts to evaluate patients with potentially compromised airways in less controlled environments such as a trauma resuscitation bay. This algorithm needs to be prospectively validated, ideally in a multi-center trial, given the overall small number of patients any one center would see in a given period of time. We found that the decision to perform surgical tracheostomy compared to endotracheal tube exchange (ETT) is difficult in trauma patients. Craniofacial injury patterns made prehospital airway control and subsequently definitive airway management more difficult. Routine tube exchange may not be warranted or safe in trauma patients. This may be due to multiple PETI attempts or supraglottic airway insertion, which may inflict oropharyngeal trauma and can complicate definitive airway management. Our multivariable analysis demonstrated that the number of PETI attempts and increased craniofacial trauma patterns were independently associated with definitive airway managed with surgical tracheostomy compared to ETT. These data highlight that careful selection of patients necessitating surgical tracheostomy may be
Table 2 Patient and injury characteristics, by type of definitive airway, values otherwise reported as medians with interquartile range Outcome
Tracheostomy Endotracheal tube N = 20 exchange (ETT) N = 36
p-Value
Overall mortality rate 24 hour mortality rate Post definitive airway complication rate Facial AIS Head AIS Cervical AIS Blunt trauma rate Supraglottic airway dwell time (minutes) # of PETI failed attempts ISS Prehospital airway complication rate Duration of stay (days) Duration of mechanical ventilation (days)
40% 15% 11.1%
75% 56% 17%
0.02 0.004 1
4 [3–4] 2 [1–3] 4 [2–5] 90% 104 [87–138]
0 [0–2] 0 [0–1] 4 [3–5] 97% 61 [46–80]
0.001 0.003 0.6 0.4 0.001
2 [2–3] 35 [21–43] 95%
1 [0–2] 26 [23–38] 44%
0.001 0.4 0.0001
2 [1–7] 2 [1–4]
14 [4–25] 6 [1−13]
0.002 0.01
PETI: prehospital endotracheal intubation, AIS: abbreviated injury score, ISS: injury severity score, ETT: endotracheal tube exchange.
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
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Table 3 Multivariable regression demonstrating risk factors independently associated with need for surgical tracheostomy compared to endotracheal intubation
Number of prehospital failed endotracheal intubation (PETI) attempts Cervical AIS ≥3 Facial AIS ≥3
OR
95% CI
p-Value
McFadden's R2
1.4 1.8 1.3
1.1, 1.7 1.2, 4.1 1.1, 2.2
0.01 0.03 0.02
0.71
Abbreviations: CI, confidence interval; AIS, abbreviated injury score; OR, odds ratio; PETI: prehospital endotracheal intubation.
possible and that injury patterns or prehospital airway events contribute dramatically. Several limitations exist in this work. The study focuses on a small, retrospective sample with variability in prehospital airway management. While small it a systematic investigation into the complication profile of supraglottic airways in the trauma population. Furthermore, our data demonstrate a clear selection bias based on clinical judgment – patients with risk factors for difficult airways were managed more frequently with surgical airways. A prospective, randomized comparison of surgical airway and endotracheal tube exchange (ETT) is unlikely to ever be performed, and indeed, is likely unethical. Our data support a cautious approach in regard to ETT in the emergency department that emphasizes recognition of risk factors for airway distortion and a low threshold for surgical airway in high-risk patients. 5. Conclusion After supraglottic rescue airway insertion, trauma resuscitation should focus on early airway management based on patient factors, such as distorted or injured anatomy, as well as EMS factors such as number of previous intubation attempts. We demonstrate that these
factors influence the route of definitive airway management, with tracheostomy favored for patients with increased craniofacial injury patterns. Future research is necessary to confirm our findings. References [1] Hubble MW, Brown L, Wilfong DA, Hertelendy A, Benner RW, Richards ME. A metaanalysis of prehospital airway control techniques part I: orotracheal and nasotracheal intubation success rates. Prehosp Emerg Care 2010;14(3):377–401. [2] Combes X, Jabre P, Jbeili C, Leroux B, Bastuji-Garin S, Margenet A, et al. Prehospital standardization of medical airway management: incidence and risk factors of difficult airway. Acad Emerg Med 2006;13(8):828–34. [3] Hilton MT, Wayne M, Martin-Gill C. Impact of system-wide king LT airway implementation on orotracheal intubation. Prehosp Emerg Care 2016;3127(July):1–8. [4] van Tulder R, Schriefl C, Roth D, Stratil P, Thalhammer M, Wieczorek H, et al. Laryngeal tube practice in a metropolitan ambulance service: a five-year retrospective observational study (2009–2013). Prehosp Emerg Care 2016;3127(July):1–7. [5] Subramanian A, Garcia-Marcinkiewicz AG, Brown DR, Brown MJ, Diedrich DA. In reply: definitive airway management in emergency department patients with a King laryngeal tube™ in place: a simple and safe approach. Can J Anesth 2016; 63(5):640. [6] Koumpan Y, Murdoch J, Beyea JA, Kahn M, Colbeck J. A case report. A A Case Rep 2017;8(6):139–41. [7] Jensen JL, Cheung KW, Tallon JM, Travers AH. Comparison of tracheal intubation and alternative airway techniques performed in the prehospital setting by paramedics: a systematic review. Can J Emerg Med 2010;12(2):135–40.
Fig. 3. Proposed algorithm describing pathway for management of a supraglottic rescue airway device in patients with trauma.
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
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[8] Wiese CHR, Semmel T, Müller JU, Bahr J, Ocker H, Graf BM. The use of the laryngeal tube disposable (LT-D) by paramedics during out-of-hospital resuscitation-an observational study concerning ERC guidelines 2005. Resuscitation 2009;80(2):194–8. [9] Hagberg C, Bogomolny Y, Gilmore C, Gibson V, Kaitner M, Khurana S. An evaluation of the insertion and function of a new supraglottic airway device, the King LT™, during spontaneous ventilation. Anesth Analg 2006;102(2):621–5. [10] Frascone RJ, Wewerka SS, Griffith KR, Salzman JG. Use of the King LTS-D during medication-assisted airway management. Prehosp Emerg Care 2009;13(4):541–5. [11] Katz SH, Falk JL. Misplaced endotracheal tubes by paramedics in an urban emergency medical services system. Ann Emerg Med 2001;37(1):32–7. [12] Lutes M, Worman DJ. An unanticipated complication of a novel approach to airway management. J Emerg Med Elsevier Inc 2010;38(2):222-4. [13] Gaither JB, Matheson J, Eberhardt A, Colwell CB. Tongue engorgement associated with prolonged use of the King-LT laryngeal tube device. Ann Emerg Med Elsevier Inc 2010;55(4):367-9. [14] Matioc AA, Genzwuerker HV. Why go blind when you can see? J Emerg Med Elsevier Inc 2012;42(6):702-3. [15] Schalk R, Seeger FH, Mutlak H, Schweigkofler U, Zacharowski K, Peter N, et al. Complications associated with the prehospital use of laryngeal tubes-a systematic
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Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma patients☆ Matthew C. Hernandez, MD a,⁎, Johnathon M. Aho, MD a, Martin D. Zielinski, MD a, Scott P. Zietlow, MD a, Brian D. Kim, MD a, David S. Morris, MD b a b
Division of Trauma Critical Care and General Surgery, Department of Surgery, Mayo Clinic, Rochester, MN, USA Division of General Surgery, Trauma, and Critical Care, Intermountain Medical Center, Murray, UT, USA
a r t i c l e
i n f o
Article history: Received 27 June 2017 Received in revised form 9 September 2017 Accepted 14 September 2017 Available online xxxx Keywords: Prehospital Airway Supraglottic airway Trauma Tracheostomy
a b s t r a c t Background: Prehospital airway management increasingly involves supraglottic airway insertion and a paucity of data evaluates outcomes in trauma populations. We aim to describe definitive airway management in traumatically injured patients who necessitated prehospital supraglottic airway insertion. Methods: We performed a single institution retrospective review of multisystem injured patients (≥15 years) that received prehospital supraglottic airway insertion during 2009 to 2016. Baseline demographics, number and type of: supraglottic airway insertion attempts, definitive airway and complications were recorded. Primary outcome was need for tracheostomy. Univariate and multivariable statistics were performed. Results: 56 patients met inclusion criteria and were reviewed, 78% were male. Median age [IQR] was 36 [24–56] years. Injuries comprised blunt (94%), penetrating (4%) and burns (2%). Median ISS was 26 [22–41]. Median number of prehospital endotracheal intubation (PETI) attempts was 2 [1-3]. Definitive airway management included: (n = 20, 36%, tracheostomy), (n = 10, 18%, direct laryngoscopy), (n = 6, 11%, bougie), (n = 9, 15%, Glidescope), (n = 11, 20%, bronchoscopic assistance). 24-hour mortality was 41%. Increasing number of PETI was associated with increasing facial injury. On regression, increasing cervical and facial injury patterns as well as number of PETI were associated with definitive airway control via surgical tracheostomy. Conclusions: After supraglottic airway insertion, operative or non-operative approaches can be utilized to obtain a definitive airway. Patients with increased craniofacial injuries have an increased risk for airway complications and need for tracheostomy. We used these factors to generate an evidence based algorithm that requires prospective validation. Level of evidence: Level IV – Retrospective study. Study type: Retrospective single institution study. © 2017 Elsevier Inc. All rights reserved.
1. Introduction A functional and patent airway during prehospital resuscitation is a critical consideration of trauma resuscitation [1]. Several risk factors confound prehospital airway control such as obesity and craniofacial trauma [2]. Supraglottic devices may be utilized for the difficult airway
☆ Author contribution: Study design was developed by Matthew Hernandez, Johnathon Aho, David Morris, and Martin Zielinski. Data generation was performed by Matthew Hernandez. Data analysis and interpretation was performed by Matthew Hernandez, Johnathon Aho, Martin Zielinski, Scott Zietlow, Brian Kim, and David Morris. Manuscript writing was performed by Matthew Hernandez, Johnathon Aho, Scott Zietlow, Brian Kim, David Morris and Martin Zielinski. ⁎ Corresponding author at: Division of Trauma Critical Care and General Surgery, Department of Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. E-mail addresses: [email protected] (M.C. Hernandez), [email protected] (J.M. Aho), [email protected] (M.D. Zielinski), [email protected] (B.D. Kim), [email protected] (D.S. Morris).
[1,3-5]. After supraglottic device insertion, methods to secure a definitive airway include direct laryngoscopy, blind tube exchange or fiberoptic guidance [6]. In cardiac arrest, supraglottic airway exchange may not be urgent as the primary focus is restoration of spontaneous circulation [7]. Conversely, the trauma resuscitation focuses on constant airway assessment to gauge patency and adequate ventilation. This is the unique difference; maintenance of airway control and prevention of dysoxia while systematically triaging injury care by severity whereas medical resuscitations aim to restore and maintain cardiac flow. In the prehospital setting, supraglottic devices provide initial airway control with ease of insertion [8-10]. These advancements come at the expense of potential complications. Morbidity such as gastric distension, tube malposition and oropharyngeal edema resulting abrupt airway occlusion can occur [5,11-15]. Management algorithms exist to secure a definitive airway after supraglottic device insertion; however, these recommendations are from variable populations [16-19]. For trauma patients necessitating prehospital supraglottic airways, there is a
http://dx.doi.org/10.1016/j.ajem.2017.09.028 0735-6757/© 2017 Elsevier Inc. All rights reserved.
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
2
M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
lack of evidence to adequately address definitive airway management. Therefore, we aimed to determine which definitive airway techniques were utilized after prehospital supraglottic device insertion in multisystem injured patients hypothesizing that patients with increased prehospital airway complications and craniofacial injury patterns would require advanced airway control, including surgical tracheostomy.
with 95% confidence intervals (CI). Data was analyzed with JMP (SAS Institute, Inc. Cary NC). We utilized GraphPad Prism (GraphPad Software, Inc. La Jolla CA) for all visual graphics.
2. Methods
The study cohort consisted of 56 patients with multisystem trauma and supraglottic airway insertion. The median [IQR] ISS was 26 [22– 41] and 78% of patients were male. The mean (± SD) age was 39.6 (± 21.2) years. Most patients (72%) were transported via rotor wing and median [IQR] transport time was 20 [13 − 33] minutes. Mean (± SD) body mass index (BMI) was 29.2 (± 6.6). The median [IQR] head, neck and facial abbreviated injury scores (AIS) were: head 4 [35], neck 2 [0–3], face 1 [0–2] respectively, Table 1. Mechanisms of injury included blunt (n = 53, 94%), penetrating (n = 2, 4%), and burn (n = 1, 2%).
2.1. Patient cohort From 2009 to 2016, we performed a single center retrospective study examining patients N15 years old with multisystem trauma defined as an Injury Severity Score of ≥9 that necessitated prehospital insertion of a supraglottic airway (patients receiving only a King Airway Device, King LT-D, Noblesville, IN). Patients were identified from the Mayo Clinic Trauma Center registry. Institutional review board approval was obtained prior to data review. Patients that refused research consent, received prehospital endotracheal tube intubation (PETI), were pregnant, or without multisystem trauma were excluded. 2.2. Prehospital airway institutional protocol Patients were transported by a critical care trained rotor wing team or ground transport. Injured patients that require advanced prehospital airway management meet criteria for our highest level trauma activation, which includes Emergency Medicine, Surgery, and Anesthesia providers to be present at patient arrival. Each prehospital airway intervention at our facility is reviewed in detail by the directors of Medical Transportation, Emergency Medicine, Trauma Surgery, and Anesthesia divisions. A prehospital advanced airway control algorithm (Fig. 1) has been defined and implemented by this group to standardize difficult airway management in the prehospital setting. This algorithm is designed for use after clearly defined “failure” of standard prehospital endotracheal intubation (PETI) attempts and after non-invasive ventilation is determined to be inadequate. 2.3. Outcomes and predictors The primary outcome for this study was need for tracheostomy. If a tracheostomy was not performed and instead an endotracheal tube exchange (ETT) was performed, the method of ETT was recorded (direct laryngoscopy, bougie, Glidescope, bronchoscopic assistance). Patient demographics, transportation method and duration, traumatic mechanism, trauma severity (ISS and abbreviated injury scores (AIS)), admission vital signs (heart rate, respiratory rate, systolic and diastolic blood pressure and oxygen saturation), Glasgow Coma Score (GCS), 24 h and overall mortality, frequency and type of prehospital airway complications, and number of PETI, and durations of intensive care, mechanical ventilation or overall hospital stay were abstracted from the electronic record. Mortality was defined according to definitions reported previously [20]. 2.4. Statistical analyses Summary statistical and univariate analyses were performed. Continuous variables were described using means with standard deviations (SD) if normally distributed and medians with inter-quartile ranges [IQR] for non-normally distributed data and two tailed t-tests were performed between definitive airway techniques, endotracheal tube exchange (ETT) versus surgical tracheostomy. Categorical variables were summarized as proportions, and differences were evaluated using chisquare analysis. All p-values were considered significant at p b 0.05. Clinical and statistically significant variables were evaluated to assess for risk factors for 24-h mortality using nominal logistic regression
3. Results 3.1. Baseline demographics
3.2. Prehospital airway characteristics In the prehospital setting, supraglottic device indications included failed PETI (n = 56, 100%). The median [IQR] attempts at PETI were 2 [2–3]. The number of failed PETI attempts increased in patients with increased craniofacial injury patterns Fig. 2. At arrival, all patients had a patent and functional airway provided by the supraglottic device. During prehospital resuscitation, there were 35 (63%) complications including significant laryngeal or oropharyngeal edema preventing PETI (n = 22, 63%) and supraglottic airway dislodgement (n = 13, 37%). 3.3. In hospital outcomes and definitive airway management Techniques for in hospital definitive airway included ETT (n = 36; 64%) or surgical tracheostomy (n = 20; 36%). For patients managed with ETT, 50% (n = 18) were performed in the emergency room and 50% (n = 18) were performed in the operating room. Table 2 compares outcomes and secondary predictors by definitive airway and this demonstrates the association of increased craniofacial injury patterns with a need for surgical tracheostomy. In patients who required definitive airway with a surgical tracheostomy, compared to ETT, there was an increased median facial AIS (4 [3-4] versus 1 [0–2], p b 0.0001). There was no statistically significant difference in median head AIS (4 [2–5] versus 4 [2–5]) injury severity but there was an approach to statistical significance and likely clinical significance in patients with increased median cervical AIS (2 [0–3] versus 1 [0–2], p = 0.08). Multivariable analysis demonstrated that the following factors were independently associated with need for surgical tracheostomy compared to ETT in patients with a prehospital supraglottic rescue airway: Facial AIS ≥3, cervical AIS ≥ 3, and number of PETI attempts, Table 3. During definitive airway management (open tracheostomy or endotracheal tube exchange (ETT)), the median [IQR] oxygen saturation nadir was significantly lower in patients that received ETT compared to open tracheostomy, (84% [75–89] versus 92% [88–94], p = 0.007). This difference disappeared within 10 min of definitive airway management completion (99 [96–99] versus 99 [96–100], p = 0.8). There were no long-term complications from surgical tracheostomy or ETT during follow up, median 13 [1–37] months. There were 23 patients that expired. Causes for mortality included myocardial infarction (n = 3), pulmonary contusion (n = 4), and tension pneumothorax (n = 3), traumatic brain injury (n = 5), and hemorrhagic shock (n = 8). No deaths were related to inpatient airway complications. There was less overall mortality in those receiving tracheostomy compared to those undergoing ETT (n = 8, (24%) versus n = 27, (77%), p = 0.01). With respect to 24-hour mortality, a more pronounced difference existed between patients undergoing tracheostomy compared to ETT (n = 3, (13%) versus n = 20, (87%), p = 0.004).
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
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Fig. 1. Institutional clinic prehospital transport airway management algorithm (after first failed attempt).
4. Discussion This analysis underscores several challenges, prehospital airway complications, and important clinical outcomes in patients receiving
supraglottic airway insertion. We demonstrate that after prehospital supraglottic airway insertion in polytrauma, definitive airway management via surgical tracheostomy was associated with severe craniofacial injury patterns and multiple PETI attempts. Moreover, we
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
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M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
Table 1 Patient characteristics comparing definitive airway technique Characteristic
Overall (n = 56) No. (%)
Endotracheal tube exchange (ETT) (n = 36) No. (%)
Tracheostomy (n = 20) No. (%)
p value
Baseline demographics Age, median [IQR] Male BMI, median [IQR]
36 [24–56] 44 (79) 29 [24–33]
33 [21–55] 16 (80) 31 [2–34]
41 [26–59] 28 (78) 28 [24–33]
0.6 0.7 0.6
Prehospital metrics Prehospital transport time, median [IQR]
25 [15–33]
25 [18–39]
21 [12−32]
0.2
Patient physiology Heart rate, median [IQR] Respiratory rate, median [IQR] Oxygen saturation, median [IQR] Systolic blood pressure, median [IQR] Diastolic blood pressure, median [IQR]
110 [96–116] 22 [17–26] 96 [87–99] 104 [80–123] 60 [50–80]
112 [101–117] 24 [20–27] 87 [66–94] 106 [72–128] 64 [50–81]
110 [81–116] 21 [16–37] 84 [68–96] 103 [84–122] 61 [50–80]
0.3 0.1 0.8 0.7 0.8
Predictors ISS, median [IQR]
26 [22–41]
35 21–43]
26 [22–38]
0.3
BMI: body mass index, ISS: injury severity score, IQR: interquartile range, ETT: endotracheal tube exchange.
demonstrated that those who received surgical tracheostomy as a definitive airway had minimal oxygen saturation fluctuation compared to those with endotracheal tube exchange (ETT). This analysis provides preliminary data for the role of adjunct airways, granular complication data, and initial implications for definitive airway management in adult trauma patients. Airway assessment and control is a primary objective during trauma resuscitation. For supraglottic airways in trauma, minimal evidence exists to guide definitive airway management (16). Subramanian et al. reported that for patients presenting with supraglottic airways, few had associated trauma, and in those patients the definitive airway was managed using a surgical tracheostomy in the majority (5). The present study is comprised entirely of multisystem trauma patients. Our analysis provides a trauma only cohort that analyzes subsequent definitive airway management. Patients with multisystem trauma pose a significant challenge for airway control. In the prehospital setting, two priorities are of equal value 1) minimization of airway iatrogenic injury and 2) rapid transport to definitive care. Supraglottic devices, such as the King LT™, are one method to provide a temporary airway. Since these devices are increasingly utilized, a comprehensive analysis of the indications, complications, and subsequent definitive airway management has not been adequately provided. We demonstrated that for patients with increasing craniofacial trauma, definitive airway management after supraglottic airway insertion is associated with tracheostomy compared to ETT. This finding echoes other work which has advocated for the use of tracheostomy in the management of definitive airways after supraglottic airway device insertion [16]. Definitive airway management requires rapid assessment and an actionable plan amidst the multiple priorities that occur in trauma resuscitation. The association of increasing number of PETI attempts and
Fig. 2. Increased facial trauma, (AIS grade), associated with increased prehospital endotracheal intubation. * denotes p b 0.05.
craniofacial injury patterns with surgical tracheostomy justifies our proposed definitive airway algorithm, as shown in Fig. 3. Patients who meet criteria would have, at the minimum, definitive airway evaluation in the operative room as opposed to trauma resuscitation bay. Application of these criteria may prevent premature attempts to evaluate patients with potentially compromised airways in less controlled environments such as a trauma resuscitation bay. This algorithm needs to be prospectively validated, ideally in a multi-center trial, given the overall small number of patients any one center would see in a given period of time. We found that the decision to perform surgical tracheostomy compared to endotracheal tube exchange (ETT) is difficult in trauma patients. Craniofacial injury patterns made prehospital airway control and subsequently definitive airway management more difficult. Routine tube exchange may not be warranted or safe in trauma patients. This may be due to multiple PETI attempts or supraglottic airway insertion, which may inflict oropharyngeal trauma and can complicate definitive airway management. Our multivariable analysis demonstrated that the number of PETI attempts and increased craniofacial trauma patterns were independently associated with definitive airway managed with surgical tracheostomy compared to ETT. These data highlight that careful selection of patients necessitating surgical tracheostomy may be
Table 2 Patient and injury characteristics, by type of definitive airway, values otherwise reported as medians with interquartile range Outcome
Tracheostomy Endotracheal tube N = 20 exchange (ETT) N = 36
p-Value
Overall mortality rate 24 hour mortality rate Post definitive airway complication rate Facial AIS Head AIS Cervical AIS Blunt trauma rate Supraglottic airway dwell time (minutes) # of PETI failed attempts ISS Prehospital airway complication rate Duration of stay (days) Duration of mechanical ventilation (days)
40% 15% 11.1%
75% 56% 17%
0.02 0.004 1
4 [3–4] 2 [1–3] 4 [2–5] 90% 104 [87–138]
0 [0–2] 0 [0–1] 4 [3–5] 97% 61 [46–80]
0.001 0.003 0.6 0.4 0.001
2 [2–3] 35 [21–43] 95%
1 [0–2] 26 [23–38] 44%
0.001 0.4 0.0001
2 [1–7] 2 [1–4]
14 [4–25] 6 [1−13]
0.002 0.01
PETI: prehospital endotracheal intubation, AIS: abbreviated injury score, ISS: injury severity score, ETT: endotracheal tube exchange.
Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028
M.C. Hernandez et al. / American Journal of Emergency Medicine xxx (2017) xxx–xxx
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Table 3 Multivariable regression demonstrating risk factors independently associated with need for surgical tracheostomy compared to endotracheal intubation
Number of prehospital failed endotracheal intubation (PETI) attempts Cervical AIS ≥3 Facial AIS ≥3
OR
95% CI
p-Value
McFadden's R2
1.4 1.8 1.3
1.1, 1.7 1.2, 4.1 1.1, 2.2
0.01 0.03 0.02
0.71
Abbreviations: CI, confidence interval; AIS, abbreviated injury score; OR, odds ratio; PETI: prehospital endotracheal intubation.
possible and that injury patterns or prehospital airway events contribute dramatically. Several limitations exist in this work. The study focuses on a small, retrospective sample with variability in prehospital airway management. While small it a systematic investigation into the complication profile of supraglottic airways in the trauma population. Furthermore, our data demonstrate a clear selection bias based on clinical judgment – patients with risk factors for difficult airways were managed more frequently with surgical airways. A prospective, randomized comparison of surgical airway and endotracheal tube exchange (ETT) is unlikely to ever be performed, and indeed, is likely unethical. Our data support a cautious approach in regard to ETT in the emergency department that emphasizes recognition of risk factors for airway distortion and a low threshold for surgical airway in high-risk patients. 5. Conclusion After supraglottic rescue airway insertion, trauma resuscitation should focus on early airway management based on patient factors, such as distorted or injured anatomy, as well as EMS factors such as number of previous intubation attempts. We demonstrate that these
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Fig. 3. Proposed algorithm describing pathway for management of a supraglottic rescue airway device in patients with trauma.
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Please cite this article as: Hernandez MC, et al, Definitive airway management after pre-hospital supraglottic airway insertion: Outcomes and a management algorithm for trauma pati..., American Journal of Emergency Medicine (2017), http://dx.doi.org/10.1016/j.ajem.2017.09.028