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Abstract
Rationale: Airway management in the intensive care unit (ICU) is challenging, as many patients have limited physiologic reserve and are at risk for clinical deterioration if the airway is not quickly secured. In academic medical centers, ICU intubations are often performed by trainees, making airway management education paramount for pulmonary and critical care trainees.
Objectives: To improve airway management education for our trainees, we developed a comprehensive training program including an 11-month simulation-based curriculum. The curriculum emphasizes recognition of and preparation for potentially difficult intubations and procedural skills to maximize patient safety and increase the likelihood of first-attempt success.
Methods: Training is provided in small group sessions twice monthly using a high-fidelity simulation program under the guidance of a core group of two to three advanced providers. The curriculum is designed with progressively more difficult scenarios requiring critical planning and execution of airway management by the trainees. Trainees consider patient position, preoxygenation, optimization of hemodynamics, choice of induction agents, selection of appropriate devices for the scenario, anticipation of difficulties, back-up plans, and immediate postintubation management. Clinical performance is monitored through a continuous quality improvement program.
Measurements and Main Results: Sixteen fellows have completed the program since July 1, 2013. In the 18 months since the start of the curriculum (July 1, 2013–December 31, 2014), first-attempt success has improved from 74% (358/487) to 82% (305/374) compared with the 18 months before implementation (P = 0.006). During that time there were no serious complications related to airway management. Desaturation rates decreased from 26 to 17% (P = 0.002). Other complication rates are low, including aspiration (2.1%), esophageal intubation (2.7%), dental trauma (0.8%), and hypotension (8.3%). First-attempt success in a 6-month period after implementation (July 1, 2014–December 31, 2014) was significantly higher (82.1 compared with 70.9%, P = 0.03) than during a similar 6-month period before implementation (July 1, 2012–December 31, 2012).
Conclusions: This comprehensive airway curriculum is associated with improved first-attempt success rate for intensive care unit intubations. Such a curriculum holds the potential to improve patient care.
Airway management in the intensive care unit (ICU) can be quite challenging. Patients often lack physiologic reserve, leaving them at increased risk of hemodynamic deterioration, severe hypoxemia, and cardiac arrest (1–13). Due to the high risk of clinical decompensation in the periintubation period, especially with unsuccessful attempts, first-attempt success is a high priority (14–17).
These challenging patients are often intubated by relatively inexperienced providers, and controversy exists regarding who should be responsible for airway management in these patients (3, 9, 10, 15, 18–23). Previous simulation experiences have been shown to improve clinical skills and confidence but not knowledge base; however, these experiences are almost exclusively in anesthesia trainees, medical students, and prehospital providers (24). Moreover, educational programs have shown only modest outcomes (25), whereas airway management protocols have been successful in reducing complications (22).
Our comprehensive airway management training program is based on several key principles: (1) identification of the potentially difficult airway; (2) preprocedural optimization of oxygenation, hemodynamics, and team and equipment preparation; (3) device and induction agent selection to optimize first-attempt success, with a backup plan in the event of first-attempt failure; and (4) navigation of our difficult airway algorithm to avoid airway-related complications. In addition, this program consists of several components to improve knowledge base and performance of those key principles, including: (1) a continuous quality improvement (CQI) database, (2) comprehensive simulation experience, and (3) dedicated didactics on airway management principles. These components of training are aligned with current trends in medical education highlighting milestones and incorporating objective observation to evaluate if a trainee is competent to perform procedures independently. We present an analysis of our 3-year experience with a comprehensive airway management educational program developed for our pulmonary and critical care trainees.
In the 18 months before the initiation of the training program (January 1, 2012–June 30, 2013), fellows received 4 hours of simulation training in their first-year orientation covering basic and advanced airway management topics. On July 1, 2013, we implemented an 11-month simulation curriculum designed to emphasize the recognition of anatomically and physiologically difficult intubations and the use of various techniques, including appropriate mask ventilation, supraglottic devices, direct laryngoscopy with adjunct use, video laryngoscopy, fiberoptic intubation, and emergent surgical airways.
Training is provided in small-group sessions twice monthly using a high-fidelity simulation program under the guidance of a core group of two to three advanced providers. The curriculum is designed with progressively more difficult scenarios, requiring critical planning and execution of airway management by the fellows (Table 1). The scenarios are designed to teach the fellows to navigate through preintubation preparation (Figure 1) and the difficult airway algorithm used at our facility (Figure 2). Fellows must consider patient position, preoxygenation, optimization of hemodynamics, choice of induction agents, selection of appropriate devices for the scenario, anticipation of difficulties, back-up plans, and immediate postintubation management. Each scenario is followed by a critique and discussion session led by the attending physician. The curriculum is flexible, allowing for scenarios to be added or changed as needed. Clinical performance is monitored through a CQI program.
| Month | Scenario(s) | Specific Teaching Objectives (Nonexhaustive) |
|---|---|---|
| 1 | Airway anatomy, algorithms, preintubation preparation, and device demonstration | Anatomy and physiology review, preintubation “checklists,” ability to demonstrate the use of available airway devices |
| 2 | Sedation for procedure case leads to respiratory failure | Use of bag-mask ventilation, oral/nasal airways, and supraglottic device. Benzodiazepine/narcotic reversal |
| 3 | a. Patient with hepatic encephalopathy | a. Proper positioning, anticipated laboratory abnormalities, question of GI bleed, choice of induction agents, choice of device |
| b. Patient with rheumatoid arthritis presents with a stroke and respiratory failure. | b. Cervical immobility, pretreatment options for intracranial injury, choice of device, preoxygenation, and apneic oxygenation | |
| c. Pregnant patient in third trimester develops eclampsia. | c. Patient positioning, anticipate laboratory abnormalities, preoxygenation, choice of induction agent, choice of device, and tube size | |
| 4 | Crash airway in a patient from wards | Intubation during “code blue” |
| 5 | Massive upper GI bleed | Device choice, lens contamination in fiberoptic devices, induction agents, blind airway |
| 6 | Morbidly obese patient with pneumonia | Patient position, preoxygenation, choice of medications, device selection |
| 7 | Post H1N1 pneumococcal pneumonia with severe hypoxemia and hypotension | Preoxygenation, RSI, early definitive airway and positive pressure ventilation, immediate postintubation management |
| 8 | Severe upper airway obstruction | “Awake Intubation,” fiberoptic device usage, sedation options |
| 9 | Can’t Intubate/Can Oxygenate scenario | Navigation of the difficult airway algorithm with backup plans (“plan B, C, etc.”), supraglottic devices |
| 10 | Can’t Intubate/Can’t Oxygenate scenario | Navigation of the difficult airway algorithm with backup plans, supraglottic devices/surgical airway |
| 11 | Hypoxemic, hypotensive patient with unrecognized tracheal stenosis | Multiple attempts, multiple providers, surgical airway |
Figure 1. Preintubation preparation. BP = blood pressure; BVM = bag-valve mask; IV = intravenous; NIPPV = noninvasive positive pressure ventilation; NPA = nasopharyngeal airway; NRB = nonrebreather; OPA = oropharyngeal airway; RSI = rapid-sequence intubation.
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Figure 2. Airway algorithm. 1Crash airway is defined as an emergent scenario such as cardiac arrest in which there is no time to assess potential difficulty or alter the initial intubation plan due to severity of the situation. The best option is laryngoscopy with or without neuromuscular blockade. 2In our intensive care unit, video laryngoscopy is the preferred method of laryngoscopy over direct laryngoscopy. In the absence of any difficult airway predictors, direct laryngoscopy may be attempted but should be performed with the C-MAC and the monitor turned so the supervisor can observe. 3Potential difficulty includes both anatomic and physiologic challenges. Anatomic challenges include any that may impede visualization of the vocal cords or insertion of the endotracheal tube. These include: obesity; cervical immobility; short neck; large tongue; small mandible; limited mouth opening; blood, vomit, or excessive secretions in the airway; or airway edema. Further challenges include altered anatomy from radiation, tumors, or swelling, and poor lung compliance from intrinsic lung disease or obesity. These all make intubation and/or mask ventilation and/or surgical airway difficult. Physiologic challenges are any derangement that, although it may not make visualization of the airway or insertion of the endotracheal tube difficult, it may alter the intubation plan based on inability to tolerate transition to positive pressure ventilation or apnea. These include: hypotension, severe hypoxemia (i.e., acute respiratory distress syndrome), severe metabolic acidosis (i.e., diabetic ketoacidosis, acetylsalicylic acid overdose), and right ventricular failure. 4Plan A may include any device or pharmacologic plan. For example, video laryngoscopy with neuromuscular blockade, awake fiberoptic intubation, etc. 5In the event of a failed first attempt at intubation, if mask ventilation is adequate a second attempt can occur. This may include a change in blade, device, plan, positioning, operator, pharmacologic assistance, etc. In the event that mask ventilation is not adequate and the operator is faced with a Can’t Intubate, Can’t Oxygenate scenario, the priority is no longer intubation but rather maintaining oxygenation. A supraglottic airway (Laryngeal Mask Airway, Intubating Laryngeal Mask Airway, King Airway, Combitube, etc.) should be placed. If oxygenation and ventilation can be maintained with a supraglottic airway (SGA), the next plan can be pursued. If not, a surgical airway should be performed immediately. Of course, one may encounter a situation in which an SGA would be bypassed and surgical airway performed (i.e., epiglottitis, laryngeal tumor, etc.). BVM = bag-valve mask; DL = direct laryngoscopy; NIPPV = noninvasive positive pressure ventilation; VL = video laryngoscopy.
[More] [Minimize]Fellows have protected time for didactics on Tuesday afternoons and are given lectures annually on updates in airway management, review of advanced airway management, protocols, and management of the physiologically difficult airway. The clinical experience in our fellowship is skewed toward a heavy clinical load, with 7 ICU months in Year 1, 7 in Year 2, and 3 in Year 3.
This study was conducted at a major academic referral center with a 20+ bed medical ICU, staffed by two teaching teams. Patients may overflow into surrounding critical care units, and a team census ranges from 8 to 18 patients, with seasonal variation. The pulmonary critical care division provides ICU services with 19 academic faculty attending in the ICU. The fellowship consists of a 3-year accredited pulmonary/critical care medicine (Pulm/CCM) and 2-year embedded critical care medicine (CCM) fellowship program with a total of 16 fellows. Each teaching team is staffed with an attending (Pulm/CCM or CCM), a fellow (postgraduate year [PGY] 4–6), and residents (internal medicine PGY 1–3, emergency medicine PGY 2, and family medicine PGY 2). Occasionally, fellows from anesthesia or surgical critical care fellowships rotate through the medical ICU service. The majority of intubations are performed by residents, Pulm/CCM, or CCM fellows, and all intubations are performed in the presence of an attending physician.
For the duration of the study, direct laryngoscopy was available in all sizes of Macintosh and Miller Blades. Video laryngoscopy was also available throughout the entire period. Our ICU uses the following video laryngoscopes: GlideScope (GVL) (Verathon, Bothell, WA) with both reusable and disposable blade configurations with blade sizes 3 and 4, and the C-MAC (Karl Storz, Tuttlingen, Germany) with Macintosh-type blade sizes 3 and 4. Recently, we added the McGrath MAC (Covidien, Mansfield, MA) with Macintosh-type blade sizes 2 to 4, and for a short time we trialed the King Vision (King Systems, Nobelsville, IN). Flexible fiberoptic bronchoscopes are available when awake, fiberoptic intubation is appropriate. Finally, the ICU is equipped with a difficult airway cart that includes necessary airway devices and adjuncts including nasal and oral airways, gum elastic bougie and tracheal tube exchangers, percutaneous and open surgical airway kits, and intubating laryngeal mask airways in sizes 2 to 5.
After each intubation, the operator completes a data collection form, which includes the following information: patient demographics, operator specialty, operator PGY, indication for intubation, method of intubation, paralytic agent, sedative agent, device(s) used, presence of certain difficult airway characteristics (DACs), preoxygenation methods, the Cormack-Lehane view and Percentage of Glottic Opening of the airway, number of attempts at intubation, and the outcome of each attempt, including complications. Method of intubation was recorded and included rapid-sequence intubation (RSI) in which a paralytic agent was used, oral intubation in which a sedative agent only was used, and oral intubation in which no medications were used.
Standard preoperative difficult airway predictors such as the Mallampati score, thyromental distance, and neck mobility have been shown to be challenging to apply in the emergency setting due to lack of patient cooperation and the urgency to complete the intubation (26, 27). Furthermore, these difficult airway predictors, and scoring systems such as the MACOCHA (Mallampati score III or IV, apnea syndrome [obstructive], cervical spine limitation, opening mouth <3 cm, coma, hypoxia, anesthesiologist nontrained) score, have been developed primarily for direct laryngoscopy, whereas we prefer video laryngoscopy as our primary device for laryngoscopy (28). Thus, we implemented a list of DACs that are feasible for the operator to determine before intubation in an emergent setting by simple examination. These include both anatomic and physiologic difficult airway characteristics. The anatomic DACs are factors that make laryngoscopy and/or intubation more difficult. They include the presence of blood, vomit, or secretions in the airway; cervical immobility (intrinsic or due to a cervical collar); obesity; large tongue; short neck; small mandible; facial or neck trauma; airway edema; and limited mouth opening. The physiologic DACs are physiologic derangements that make the procedure more risky and thus more challenging. They include hemodynamic instability and hypoxemia.
An intubation attempt is defined as insertion of the laryngoscope blade into the oropharynx regardless of an attempt to pass the endotracheal tube (ETT). Successful intubation is defined as correct placement of the ETT in the trachea as confirmed by capnometry, pulse oximetry, chest auscultation, observation of chest excursion, absence of epigastric sounds, and misting of the ETT. If uncertainty exists about ETT placement by the operator and the tube is removed and replaced, it is considered an esophageal intubation. First-attempt success is defined as successful tracheal intubation on the initial laryngoscope insertion.
Complications evaluated include: hypotension, desaturation, esophageal intubation, aspiration, airway trauma, and “other.” Hypotension is defined as any drop in blood pressure requiring intervention, such as fluid resuscitation or initiation or titration of vasopressors, that occurs during or within 5 minutes of the intubation. Desaturation is defined as a decline in oxygen saturation greater than 10% from the baseline during the intubation procedure. Aspiration includes any witnessed aspiration of gastric contents or secretions during the intubation attempt. Airway trauma includes any lacerations, swelling, edema, or dental injury related to the airway manipulation.
The data collection forms are reviewed by the primary author for completion and cross-referenced to a weekly report generated by the electronic health record to ensure capture of all intubations and accuracy of the information reported. If the forms have any missing data that could not be obtained from the medical record, they are returned to the operator for completion. If information on the form contained inconsistencies, the operator is interviewed by the primary author for clarification.
Data are then deidentified and entered into the electronic database (Excel for Macintosh 2011; Microsoft, Redmond, WA) and transferred to Stata for analysis (Stata version 12; StataCorp, College Station, TX). This CQI database was granted exemption from full review by the University’s Institutional Review Board.
This is a pre- and postintervention analysis of the airway management program in the 18 months before implementation of the simulation curriculum (January 1, 2012–June 30, 2013) and the 18 months since implementation (July 1, 2013–December 31, 2014). The primary outcome is first-attempt success. The secondary outcome is the incidence of complications. The primary analysis examines all airway management events before and during implementation of the curriculum. An analysis was also performed comparing the periods from July 1, 2012 to December 31, 2012, before curriculum implementation, and from July 1, 2014 to December 31, 2014, after one cycle of the 11-month curriculum was completed. Each period occurs during the first 6 months of the respective academic year to minimize bias introduced by increasing clinical experience over the course of the year.
Summary statistics were generated using Fisher's exact test for categorical variables, Kruskal-Wallis test, and Student's t test where appropriate. A multivariate logistic regression model was constructed in a negative stepwise fashion, initially including method, video laryngoscopy, operator PGY, patient age, and the DACs that were different between the groups, with variables removed from the model if the odds ratio for the predictor variable did not change by more than 0.10. Method, patient age, and DACs were removed as not significantly affecting the odds ratio of the predictor variable, and a Hosmer-Lemeshow test was performed to determine goodness of fit. Descriptive statistics were performed on measured variables, with reported means, standard deviations, medians, and interquartile ranges where appropriate. All statistical analyses were performed using Stata 12 for Macintosh (StataCorp LP, College Station, TX).
Over the 3-year period, there have been 30 fellows in our program. Eight fellows graduated before implementation of the curriculum, and six started training on July 1, 2014 and have not yet completed the entire simulation curriculum. Sixteen fellows completed the simulation curriculum between July 1, 2013 and June 30, 2014. During the study period, 886 patients were intubated. Four intubations were excluded for being performed by medical students, and 21 intubations were excluded for being performed by the attending primarily. The remaining 861 intubations were included in this analysis. Of these, 56.6% (487) occurred before the introduction of the curriculum (January 1, 2012–June 30, 2013), and 43.4% (374) occurred after the introduction of the curriculum (July 1, 2013–December 31, 2014).
Table 2 summarizes patient and operator demographics. Patients intubated before the simulation curriculum were slightly older, 59.9 years versus 56.7 years, and tended to be evaluated as more commonly having a small mandible (17.7 vs. 11.8%), large tongue (15.0 vs. 10.2%), and hypoxemia (28.5 vs. 21.4%) compared with patients intubated after the initiation of the simulation curriculum. There were no other differences in difficult airway characteristics. Patients intubated after the initiation of the simulation curriculum were more likely to be intubated with RSI (75.9 vs. 68.6%). There were no significant differences in sedatives or neuromuscular blocking agents used. There was a significant difference in operator PGY between the groups, with a higher percentage of patients after initiation of the simulation experience being intubated by more experienced operators (Table 2). Table 3 shows the device selection between the two groups. Before the simulation curriculum, a higher percentage of patients were intubated with direct laryngoscopy (19.5 vs. 11.8%).
| Characteristic | Pre-Sim Lab, % (n) (n = 487) | 95% CI | Post-Sim Lab % (n) (n = 374) | 95% CI | P Value |
|---|---|---|---|---|---|
| Mean age, yr | 59.9 (IQR, 52–70) | 58.5–61.2 | 56.7 (IQR, 47–70) | 55.1–58.3 | 0.003 |
| Sex, male | 58.9 (286) | 56.3–65.1 | 53.5 (199) | 48.0–58.4 | 0.11 |
| DACs | |||||
| Total DACs (median) | 2.1 (2) | IQR, 1–3 | 1.8 (1) | IQR, 1–3 | 0.07 |
| None | 20.0 (97) | 16.6–23.9 | 18.5 (26) | 14.6–22.8 | 0.60 |
| Blood in airway | 15.4 (75) | 12.3–18.9 | 12.3 (46) | 9.1–16.1 | 0.20 |
| Vomit in airway | 6.2 (30) | 4.2–8.7 | 6.4 (24) | 4.2–9.4 | 0.88 |
| Cervical immobilization | 3.1 (15) | 1.7–5.0 | 3.2 (12) | 1.7–5.5 | 1.00 |
| Facial/neck trauma | 1.0 (5) | 0.3–2.4 | 0.8 (3) | 0.02–2.3 | 1.00 |
| Airway edema | 7.8 (38) | 5.6–10.6 | 6.2 (23) | 3.9–9.1 | 0.42 |
| Small mandible | 17.7 (86) | 14.4–21.3 | 11.8 (44) | 8.7–15.5 | 0.02 |
| Obesity | 30.2 (147) | 26.1–34.5 | 29.7 (111) | 25.1–34.6 | 0.89 |
| Large tongue | 15.0 (73) | 11.9–18.5 | 10.2 (38) | 7.3–13.7 | 0.04 |
| Short neck | 26.7 (130) | 22.8–30.9 | 22.0 (82) | 17.8–26.5 | 0.11 |
| Hypoxemia | 28.5 (139) | 22.3–30.3 | 21.4 (80) | 23.1–37.5 | 0.02 |
| Hemodynamic instability | 24.7 (120) | 20.9–28.7 | 20.1 (75) | 16.1–24.5 | 0.12 |
| Method | |||||
| Rapid sequence intubation | 68.6 (334) | 64.3–72.7 | 75.9 (284) | 71.3–80.2 | 0.04 |
| Sedation only | 27.5 (134) | 23.6–31.7 | 21.9 (82) | 17.8–26.5 | |
| No medications | 3.9 (19) | 2.4–31.7 | 2.1 (8) | 0.9–4.2 | |
| Sedatives | |||||
| Etomidate | 68.2 (318) | 60.9–69.5 | 76.3 (277) | 69.3–78.4 | |
| Ketamine | 20.6 (96) | 16.3–23.5 | 17.1 (62) | 13.0–20.7 | 0.09 |
| Midazolam | 3.4 (16) | 1.9–5.3 | 2.2 (8) | 0.9–4.2 | |
| Propofol | 6.9 (32) | 4.5–9.1 | 4.1 (15) | 2.3–6.5 | |
| Combination | 0.9 (4) | 0.2–2.1 | 0.3 (1) | 0.0–1.5 | |
| Paralytics | |||||
| Succinylcholine | 62.6 (209) | 38.5–47.4 | 66.2 (188) | 45.1–55.4 | |
| Rocuronium | 35.9 (120) | 20.9–28.7 | 32.0 (91) | 20.1–29.0 | 0.58 |
| Cisatracurium | 1.5 (5) | 0.3–2.4 | 1.8 (5) | 0.4–3.1 | |
| Operator PGY level | |||||
| 1 | 9.0 (44) | 6.6–11.9 | 5.1 (19) | 3.1–7.8 | |
| 2 | 18.8 (90) | 15.1–22.2 | 13.9 (52) | 10.6–17.8 | |
| 3 | 13.4 (65) | 10.5–16.7 | 10.7 (40) | 7.8–14.3 | 0.001* |
| 4 | 25.9 (126) | 22.0–30.0 | 27.3 (102) | 22.8–32.1 | |
| 5 | 24.2 (118) | 20.5–28.3 | 25.6 (97) | 21.6–30.7 | |
| 6 | 9.0 (44) | 6.7–11.9 | 17.1 (64) | 13.4–21.3 |
| Characteristic | Pre-Sim Lab % (n) (n = 487) | 95% CI | Post-Sim Lab % (n) (n = 374) | 95% CI | P Value |
|---|---|---|---|---|---|
| Device used | |||||
| Direct laryngoscope | 19.5 (95) | 16.1–23.3 | 11.8 (44) | 8.7–15.5 | |
| GlideScope VL | 19.3 (94) | 15.9–23.1 | 15.6 (58) | 11.9–19.6 | |
| C-MAC VL | 54.4 (265) | 49.9–58.9 | 65.4 (244) | 60.2–70.1 | <0.001 |
| Flexible fiberoptic scope | 6.4 (31) | 4.4–8.9 | 3.5 (13) | 1.9–5.9 | |
| King Vision VL | 0.4 (2) | 0.04–1.5 | 0.0 (0) | 0–1.0 | |
| McGrath MAC VL | 0.0 (0) | 0–0.75 | 3.8 (14) | 2.1–6.2 | |
| First-attempt success | |||||
| Overall | 73.5 (358) | 68.6–78.0 | 81.6 (305) | 76.8–85.8 | 0.006 |
| Direct laryngoscope | 61.1 (58) | 46.6–73.0 | 72.3 (32) | 53.3–86.3 | 0.25 |
| GlideScope VL | 83.0 (78) | 73.2–90.8 | 87.9 (51) | 76.1–95.6 | 0.49 |
| C-MAC VL | 75.5 (200) | 68.9–81.3 | 82.8 (202) | 76.7–87.6 | 0.03 |
| All video laryngoscopes | 77.0 (278) | 71.6–81.8 | 83.9 (265) | 78.8–88.0 | 0.02 |
The overall first-attempt success rate increased from 73.5 to 81.6% (P = 0.006) (Table 3). The first-attempt success increased from 61.1 to 72.3% (P = not significant) for direct laryngoscopy, 83 to 87.9% (P = not significant) for GlideScope, and 75.5 to 82.8% for C-MAC video laryngoscopy (P = 0.03). For all video laryngoscopes, the first-attempt success increased from 77.0 to 83.9% (P = 0.02). The unadjusted odds of first-attempt success for intubations after the start of the simulation curriculum is 1.59 (95% confidence interval, 1.15–2.22). When adjusted for operator level of training and the use of video laryngoscopy, the adjusted odds ratio is 1.50 (95% confidence interval, 1.05–2.13). A Hosmer-Lemeshow test for goodness of fit of 0.81 shows a good fit to the model (Table 4). First-attempt success in the first 6 months of the academic year after implementation (July 1, 2014–December 31, 2014) was significantly higher at 82.1% compared with 70.9% (P = 0.03) during the first 6 months of the academic year period before implementation (July 1, 2012–December 31, 2012).
| Variable | Successful Tube Placement on First Intubation Attempt | |||
|---|---|---|---|---|
| Unadjusted (Crude) | Adjusted* | |||
| Odds Ratio | 95% CI | Odds Ratio | 95% CI | |
| Simulation curriculum | 1.59 | 1.15–2.22 | 1.50 | 1.05–2.13 |
| Device | ||||
| Direct laryngoscope | Reference | 1.48–3.29 | Reference | 1.46–3.36 |
| Video laryngoscope | 2.21 | 2.22 | ||
| Operator PGY | ||||
| 1 | Reference | Reference | ||
| 2 | 1.90 | 0.99–3.61 | 2.26 | 1.16–4.40 |
| 3 | 1.10 | 0.57–2.12 | 1.08 | 0.56–2.10 |
| 4 | 2.28 | 1.24–4.17 | 2.53 | 1.35–4.78 |
| 5 | 2.68 | 1.44–4.98 | 2.91 | 1.52–5.58 |
| 6 | 2.25 | 1.12–4.50 | 2.10 | 1.01–4.35 |
Complication rates for all attempts are shown in Table 5. The incidence of desaturation decreased from 25.9 to 16.8% after the simulation curriculum. There were no differences in any of the other complications. Overall, there are low aspiration (2.7 vs. 2.1%) and esophageal intubation (3.3 vs. 2.7%) rates. There were four patients total with periintubation cardiac arrests (0.4%), one of which was related to the intubation itself as an unrecognized esophageal intubation with direct laryngoscopy, and only two patients required a surgical airway (0.2%).
| Complication | Pre-Sim Lab % (n) (n = 487) | 95% CI | Post-Sim Lab % (n) (n = 374) | 95% CI | P Value |
|---|---|---|---|---|---|
| Hypotension | 8.2 (40) | 6–11 | 8.3 (31) | 6–12 | 1.0 |
| Desaturation | 25.9 (126) | 22–30 | 16.8 (63) | 13–21 | 0.002 |
| Esophageal intubation | 3.3 (16) | 2–5 | 2.7 (10) | 1–5 | 0.69 |
| Aspiration | 2.7 (13) | 1–5 | 2.1 (8) | 1–4 | 0.66 |
| Airway trauma | 0.8 (4) | 0–2 | 0.8 (3) | 0–2 | 1.0 |
| Periintubation arrest | 0.2 (1) | 0–1 | 0.8 (3) | 0–2 | 0.32 |
| Surgical airway | 0 (0) | 0–1 | 0.5 (2) | 0–2 | 0.19 |
These data demonstrate that, over the time period in which the simulation curriculum was instituted, first-attempt success at tracheal intubation significantly increased. There were some differences in difficult airway characteristics, use of neuromuscular blocking agents, and operator level of training between the two groups. However, it is likely that, as a result of the curriculum, fellows may better identify high-risk situations leading to more appropriate selection of RSI, video laryngoscopy, or a more experienced operator. The increased first-attempt success rate was seen even when controlling for the level of training of the operator and device used. This increased first-attempt success was complimented by a decrease in the incidence of desaturation and overall low complication rates. The improved rate was seen for both direct and video laryngoscopy, albeit statistically significant only for video laryngoscopy. These data suggest an intensive airway management curriculum improves tracheal intubation by nonanesthesiologists in the medical ICU.
Previous experiences with simulation training, including protocol or checklist initiation for airway management, have modest results in success rate and reducing complications (22, 24, 25). Jaber and colleagues found that with implementation of an airway management bundle with 10 components and including two operators there was a decrease in the incidence of both life-threatening and minor complications (22). Our findings extend those of Mayo and colleagues, who implemented a comprehensive intubation quality improvement program for their nonanesthesiologist trainees in the medical ICU and found a first-attempt success rate of 62%, an 11% esophageal intubation rate, 14% desaturation rate (defined as saturation < 80%), and 20% difficult intubation rate requiring three or more attempts (25). Their program included novel components, such as training on team leadership and crew resource management. Similar to our program, simulation was a critical component of the training. Our findings contrast those of a recent systematic review and metaanalysis of simulation-based training for airway management that showed discouraging results in terms of translation into patient outcomes (24).
Our study shows implementation of an airway program can indeed yield improvement in patient-related outcomes. We support the concept that a program emphasizing preintubation optimization to include recognition of and preparation for the potentially difficult airway is paramount. The “difficult” airway is often defined in the literature as an intubation requiring three or more attempts with direct laryngoscopy (29, 30). As the goal is to minimize unsuccessful attempts through training and advanced modalities based on patient assessment, there is an inherent flaw to such a definition in the ICU.
Predictors of a difficult intubation, such as upper airway measurements, are difficult to perform in a critically ill patient and only pertain to difficulty with placement of the endotracheal tube (26, 27). The MACOCHA score was recently developed to predict difficult intubation in critically ill patients using conventional laryngoscopy (28). Our program stresses the adoption of video laryngoscopy for the primary device, given the clear improvement in first-attempt success and availability in most academic fellowship programs (31–37). With the use of video laryngoscopy, particularly the C-MAC video laryngoscope, operators are able to perform conventional direct laryngoscopy, as the design of the blade permits adequate visualization by compression of the tongue. However, unlike with a direct laryngoscope, the supervisor is able to observe and provide real-time feedback to the operator by viewing the video screen. An important consideration is that esophageal intubations can be immediately recognized, reducing harmful outcomes that occur with unrecognized esophageal intubations. Nevertheless, our data show an improvement in first-attempt success with direct laryngoscopy from 61.1 to 72.3% in the post-training period, albeit clinically but not statistically significant (P = 0.25).
The simulation curriculum is geared toward the identification and management of the potentially and unexpected difficult airway with progressively more difficult cases. Through this simulation experience, the trainees are taught to navigate through the airway algorithm designed for our ICU (Figure 2). The American Society of Anesthesiologists has well-established practice guidelines (29, 38), yet these guidelines do not precisely apply to the needs of critically ill ICU patients, including incomplete recall of some elements in the algorithm (39). The Canadian Airway Focus Group has published guidelines on identification and management of the difficult airway but recommends an “exit strategy” after three failed attempts, which is also difficult to use for the critically ill ICU patient (40, 41). Recently, a cognitive tool, the “Vortex Approach” has been developed as a recall aid when encountering a difficult airway (42). Our airway algorithm combines elements of all three approaches.
There are several limitations to our study. As this is an observational study with self-reported data, the results must be interpreted with caution. Second, it is impossible to completely isolate which elements of the airway curriculum make the most difference in outcomes. This analysis includes intubations performed before and after the start of the curriculum, making a substantial portion of the intubations during the implementation of the curriculum. Likewise, fellows received some airway training before the initiation of the curriculum, limiting the ability to truly isolate the effect of the curriculum in this analysis. We attempted to minimize the effect of device selection and operator level of training, yet it is impossible to eliminate them completely, as the primary goal of the curriculum is to optimize first-attempt success through device selection and plan implementation after recognition of the potentially difficult airway. Thus, operator level of training and device selection are intimately related to the success of the curriculum.
Third, although only fellows participate in the simulation curriculum, we included all intubations performed by trainees during this 36-month period in the analysis. Although the fellows may not be performing every intubation over this time period, the fellow oversees the intubation procedure and is responsible for the resident. The airway curriculum includes the intubation procedure, but the primary focus is on the periintubation assessment and management, seeking to maximize the likelihood of first-attempt success and minimize complications. When fellows are not performing the intubation procedure itself, they remain responsible for the periintubation management. As such, we believe it was important to include all intubations in this analysis. Furthermore, with video laryngoscopy, they are able to direct the resident. Fourth, our definitions of complications such as desaturation differ from those established in the literature, which typically defines desaturation as any saturation less than 80%. We choose to define desaturation greater than 10% of baseline as our indicator of desaturation, which isolates procedure-related desaturation from desaturation related to severe hypoxemic disease. Last, the use of video laryngoscopy makes it difficult to compare these data with previous studies in which direct laryngoscopy is the primary device of choice.
In an academic medical ICU staffed by pulmonary and critical care medicine fellows, and supervised by pulmonary and critical care medicine attendings, the implementation of a comprehensive airway management educational program was associated with improved clinical performance.
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A portion of this work was presented in abstract form at the Society of Airway Management annual meeting in Seattle, Washington in September, 2014.
Author Contributions: J.M.M., J.W.B., J.C.S., J.M., J.K., L.S., and K.K. designed the curriculum. J.M.M., J.W.B., J.M., C.D.H., J.C.S., and K.K. conceived the study. J.M.M. and J.C.S. designed the data collection instrument. J.M.M., C.D.H., and R.J. managed the database. J.M.M., J.M., J.C.S., and K.K. performed statistical analysis in the study. J.M.M., J.C.S., J.W.B., J.M., L.S., B.N., C.D.H., R.J., J.K., and K.K. contributed to the drafting of the manuscript. J.M.M. takes responsibility for the paper as a whole.
Author disclosures are available with the text of this article at www.atsjournals.org.
