This is the first emergency department-based airway study conducted in Bhutan providing an airway profile over 29 months of data recorded corresponding with 336 endotracheal intubations in the ED of the National Referral Hospital.
At our institution, all intubations in the ED were performed by either emergency physician, emergency medicine residents or medical officers assigned to work in the ED. This differs from practices in other countries which vary broadly where some ED intubations are performed by non emergency medicine physicians, especially the on-call anesthesiologists.(7, 8, 9) Prior studies have revealed that the specialty of the intubating physician and experience were both significant factors in predicting the rate of first pass success.(4, 10, 11) Anesthesiologist and emergency physicians had more first pass success than other specialties (surgeon, GP); residents in the first or second postgraduate year of training had more attempts at intubation than year 3 or 4 trainees or attending physicians.(4, 10, 12) In our study, 92% of the intubation in our study was done by either the emergency medicine resident or the medical officers highlighting the importance of airway management training and education for these group of doctors. Studies in the US and Japan have shown that with more airway management practice and sessions in residency programs, the first pass success rate can increase by 10–12%.(1, 2, 6)
The majority of the patients had medical indications (90.18%) for intubation while 33 (9.82%) were due to trauma. Incidence of traumatic indication for intubation varied in different studies from 5.1% to as high as 47.7%.(1, 4, 5, 8, 9, 11, 12) Higher numbers could be due to epidemiology where the trauma and accidents cases are seen more.(12) Among traumatic intubations TBI was the most common which is consistent with findings in other studies.(1, 2, 3, 9)
Of the medical indications, respiratory failure was the most common (28.38%), followed by altered mental status (24.4%) and cardiac arrest (23.51%). Other studies reveal respiratory failure is frequently the most common medical indication although a study in northern India found altered mental status.(3, 5, 7)) It is worthwhile noting that, in our study, cardiac arrest was the third most common indication for intubation of which the majority were out of hospital arrests.
It is well known that preoxygenation plays a vital role in maintaining saturation during intubation.(7, 13) Studies have shown NIPPV is superior to other methods and the importance of apneic oxygenation in preventing hypoxia.(7, 13) Approximately 2/3 of the preoxygenation was with PPV in the form of BVM or NIPPV and the remained via non rebreather face masks. Despite incorporating methods to improve oxygenation in all cases, the most common complication was desaturation in our patients. This suggests the need for further training around airway management, ensuring adequate preoxygenation, prompt recognition of hypoxia and consistent use of apneic oxygenation.
Rates of rapid sequence intubation (RSI) vary broadly around the world studies in Scotland had RSI rate of 74%, India(72.9%), Pakistan(67%) Japan (41%) and Nepal(12.5%),.(3, 4, 6, 8, 9) Studies have suggested that the muscle paralysis is responsible for most of the improvement of intubation using RSI techniques and potent sedatives can further improve the speed and success rate of NMBA facilitated intubation leading to a shift towards greater use of RSI.(1, 2, 3, 8, 10, 13) This is consistent with our study where 67.5% underwent RSI followed by intubation without medication at 21% following cardiac arrest. Sedative only intubation accounting for only 2.68% which is is contrast to some studies from neighboring countries of India, Nepal and China, but consistent with trends in other emergency departments where intubation have shifted to RSI now instead of using only sedation. (1,2,3,6,8, 910,11,13)
A surprising finding in our study was the frequency of paralytic-only intubation recorded at 8.63% (n = 29). This practice of only paralytic intubation is never an acceptable practice and exponentially increases the risk of physiological complications and psychological sequalae; yet literature reveals the practice still persists today.(14, 15, 16) We reviewed the records and charts of these intubations and all patients had crash intubations and were placed on post intubation midazolam or ketamine infusion following return of spontaneous circulation(ROSC). This highlights the need of proper intubation guidelines and training in the department focusing on adequate analgesia and sedation to decrease the rate of this practice.
Sedatives, along with playing the role of neuroprotectant, hypnotic and induction agent, facilitates RSI by synergism of muscle relaxant and modulator of hemodynamic response during intubation.(10) In our study ketamine was the most commonly used sedative accounting for 66.8.% of the intubations in which a sedative was used. Midazolam accounted for most of the remaining 21.6%, fentanyl 10.0% and rarely propofol at 1.6%. This differs from many studies as etomidate is not available at our center and has widespread use in EDs globally mainly due to the hemodynamic neutrality (1, 3, 10, 11). However multiple studies have shown ketamine as safe alternative.(12, 13, 17) The choice of induction drugs depends on the intubating physicians,\ their familiarity with the drug and clinical factors such as comorbidities and vital signs at the time of intubation such as avoiding propofol and midazolam in hypotension.(10, 13, 17)
Paralytic agents minimize complications and improve chance of first pass success during RSI.(8, 9, 13) Whereas other studies report rocuronium to be the most popular agent due to its fast acting, long duration with few contraindications it is not available in our center. (1, 3, 13, 17) Of the patients who received a paralytic, in our study, Of the patients who received a paralytic the vast majority of our patients received succinylcholine (93.3%); this majority use is similar to other studies from institutions where rocuronium is not available.(12, 13) The use of atracurium (4.7) and vecuronium (2%) were likely limited to when succinylcholine was contraindicated such as hyperkalemia, chronic kidney or burn patients.
Direct laryngoscopy was the preferred method of intubation (82.7) which is similar to some studies from India and Ethiopia.(1, 3, 12) In general studies reveal that video laryngoscopy(VL) is more popular than the direct laryngoscopy due to better glottic view, less airway trauma, first pass success in beginners. (1, 3, 7, 18, 19) During the COVID pandemic, similar to a number of other low and middle income countries, VL became available in our ED and the lack of prior experience with it is a likely contributor to its lack of consistent use.(1, 3, 12) VL use was also popular in institutions with residency training programs, highlighting the teaching potential with this method. (1, 6, 19) However, it is worth noting that systematic review has shown no differences in major complications or higher complications in some studies with VL. (7, 18). First pass success in beginners has been demonstrated to be better with VL but also increases the time for intubation or obscuring of the view with blood or secretions making patients at risk for desaturation and hypoxia.(18, 19) As a residency-training educational institution this study revealing the limited use of VL may impact the frequency of use moving forward.
RSI is being commonly used in ED for its increasing benefit in achieving first pass success and less complications which is similar to the findings in our study.(11, 13, 20) RSI showed higher rate of first pass success of 88.5% as compared to sedation only(77.8%), paralytic only(82%) and crash (87.3%) – which is similar to other studies where RSI has slightly higher rates of first pass success. (4, 8) Similarly our complication rates were observed to be slightly lower in with 19.8% in RSI, 22.2%(only sedative), 20.6% (only paralytic) and 21% (No drugs) – consistent with numerous prior studies. (2, 8) Confirmation was primarily done clinically with a 5-point auscultation method due to limited availability of waveform or qualitative end-tidal capnography.
Desaturation was the most common complication with 10.1% which is within the desaturation incidence seen in various studies varying from 1.7–13%.(3, 7, 8, 12) Desaturation and other complications were associated with multiple attempts of intubation, poor preoxygenation and without apneic oxygenation.(1, 6, 8, 12) The most serious immediate complication was cardiac arrest which occurred in 5 (1.5%) patients. We found esophageal intubation occurring at the rate similar to study done in the region at 4–5%.(3, 4, 5) These complications were identified immediately and corrected. Hypotension (3.3%) was the third common complication encountered with higher values reported in studies done in China (6.3%), India(6%) and Scotland(4.5%).(3, 7, 8)
Emergency medicine residents and EP showed more first pass success compared to medical officers (90.6% and 88.8% vs 82.6%). This could be mainly due to airway management training and practical skills received as a part of the residency program. Our medical officers’ skills depend on the number of years of practice and whether they have attended the airway training course in the ED. Studies have shown that airway experience were significant factors in predicting the first pass success with residents in first and second years in training having more attempts than the 3rd and 4th year or the attending. (4, 10, 11, 12) Our study did not differentiate years of experiences of the residents and of the medical officers but we had more senior residents conducting the intubation and juniors assisting the process.
The study also showed more complications associated with intubation done by medical officers than by the residents. These results highlight the importance of airway management training and skill sessions not only to the emergency residents but also to the medical officers working in the ED.
Limitations of study
One of the limitations is that every intubation may not have been included in the registry. Some data was collected retrospectively from the patient charts where the intubating doctors had missed to fill the airway registry. The person intubating was responsible for filling the airway registry, so potential to underreporting of the complication and reporting bias could be present.
Patient outcomes were limited to first pass success and disposition from the ED. Only immediate complications were assessed and no data were collected on long term complications. This data was obtained from a single institute where emergency medicine residents and medical officers receive extensive training on airway management and are under supervision. Therefore, these results may not represent airway management practices in nonacademic EDs.