BestBET: The Use of Point-of-Care Ultrasound in Predicting Difficult Intubations in the Emergency Department
Date First Published:
January 5, 2026
Last Updated:
January 5, 2026
Report by:
Dr Long Him Angus Chan, Foundation Year 1 Doctor (Lancashire Teaching Hospital Foundation Trust (LTHTR))
Search checked by:
Dr Cheran Saravanan, Foundation Year 1 Doctor (LTHTR)
Three-Part Question:
In (adults presenting to ED who require intubation) is (airway assessment with POCUS as effective as standard beside assessment alone) with regards to (predicting difficult airway intubation)?
Clinical Scenario:
A 44-year-old woman present to ED with severe gastrointestinal bleeding. She is actively vomiting blood and has a reduced level of consciousness requiring urgent intubation. Standard airway assessments such as Mallampati scoring are impossible due to persistent vomiting and poor cooperation. You consider calling for early senior anaesthetic help and wonder if there is any evidence supporting the use of POCUS to perform an initial assessment of the patient’s airway.
Search Strategy:
A database search using MEDLINE and EMBASE via the OVID interface was conducted to find relevant studies. The following keyword searches were used:
(Ultrasound.mp OR Ultrason*.mp OR POCUS.mp) AND (Airway.mp OR exp Intubation, Intratracheal/ or intub*.mp) AND (emergency department.mp OR emergency room.mp OR emergency care.mp OR emergency medicine.mp OR exp emergency department/ OR exp emergency care/ OR exp emergency medicine/).
(Ultrasound.mp OR Ultrason*.mp OR POCUS.mp) AND (Airway.mp OR exp Intubation, Intratracheal/ or intub*.mp) AND (emergency department.mp OR emergency room.mp OR emergency care.mp OR emergency medicine.mp OR exp emergency department/ OR exp emergency care/ OR exp emergency medicine/).
Search Details:
There were no restrictions on year of publication and language. Studies were included only if they met the following inclusion criteria:
• Adult patients (>18 years old)
• Presenting to ED requiring emergency intubation
• Airway POCUS was used prior to intubation
• Adult patients (>18 years old)
• Presenting to ED requiring emergency intubation
• Airway POCUS was used prior to intubation
Outcome:
The database search revealed 1685 results, with 244 duplicates found and removed by the algorithm and 2 duplicates manually removed. Upon title and abstract review, 1385 papers were excluded as they were not relevant to the research question. Of the remaining 11 papers, 3 were irretrievable. The remaining 8 papers were reviewed in full text. Two were determined to be out of scope as subjects were elective surgery patients and therefore not intubated in ED, while 2 papers were conference abstracts and were thus omitted from this review. The remaining 4 papers were retained for final analysis.
Citation lists of the 4 papers that met all inclusion criteria were screened on Google Scholar database to ensure that there were no studies that were missed in the above searching process. The 4 papers were also screened on Google Scholar for papers which cited them for further search. No additional studies were eligible for the final analysis.
These 4 studies comprised of a total sample size of 353 patients and were all observational studies.
Citation lists of the 4 papers that met all inclusion criteria were screened on Google Scholar database to ensure that there were no studies that were missed in the above searching process. The 4 papers were also screened on Google Scholar for papers which cited them for further search. No additional studies were eligible for the final analysis.
These 4 studies comprised of a total sample size of 353 patients and were all observational studies.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| The diagnostic accuracy of point-of-care ultrasound parameters for airway assessment in patients undergoing intubation in emergency department—an observational study Aadya Pillai, Poonam Arora, Ankita Kabi, Udit Chauhan, Reshma Asokan, P. Akhil, Takshak Shankar, D. J. Lalneiruol, Himanshi Baid & Hannah Chawang 29 Jan 2024 India | Adults who presented to the ED requiring intubation. N=70, mean age: 51.41, males: 78.6%. | POCUS was performed using a 2-5MHz curvilinear probe whilst the patient was supine. A 6-13 MHz linear probe was also used. CL grading assessment followed by intubation was then performed | Sensitivity, specificity and AUROC of the following: Hyomental distance; Tongue thickness; Pre-epiglottic to epiglottic vocal cord ratio (Pre-E/E-VC); Distance from skin to hyoid bone | There was no significant relationship between difficult intubation and distance from skin to hyoid bone. All other parameters can act as a tool for predicting difficult intubation, with the single best parameter being Pre-E/E-VC (sensitivity: 83%, specificity: 94%). | This was a single centre study. The distribution of CL grades in the sample is uneven; some grades (like CL grade 4) were rare. The inter-observer variability of POCUS was not assessed and the demographic variation of participants was not considered. |
| Prediction of difficult laryngoscopy / difficult intubation cases using upper airway ultrasound measurements in emergency department: a prospective observational study Mehran Sotoodehnia, Maryam Khodayar, Alireza Jalali, Mehdi Momeni, Arash Safaie & Atefeh Abdollahi 25 July 2023 Iran | Adults who presented to the ED requiring intubation. N=123, mean age: 68.83, males: 52%. | A 6-13MHz linear probe was used whilst the patient was supine. CL grading assessment followed by intubation was then performed. | Sensitivity, specificity and AUROC of the following: Distance from skin to hyoid bone; Hyoid bone visibility; Distance from skin to vocal cord; Distance from skin to thyroid isthmus; Distance between arytenoids cartilage | There was no significant relationship between difficult intubation and distance between arytenoids cartilage. All other parameters can act as a tool for predicting difficult intubation. | This was a single centre study. There was a low prevalence of difficult intubations in the sample. Certain patients were excluded from the sample (e.g. neck/face trauma, cervical collars, crash intubations). Ultrasonography was performed by a single doctor, meaning findings could vary with other operators. |
| Diagnostic Accuracy of Ultrasound Measurements of Anterior Neck Soft Tissue in Determining a Difficult Airway Srinivasarangan, Madhu; Akkamahadevi, P.; Balkal, Veeresh C.; Javali, Rameshbabu Homanna Jan-Mar 2021 India | Adults who presented to the ED requiring intubation. N=60, mean age: not provided, males: 78.3%. | A 6-13MHz linear probe was used whilst the patient was supine. CL grading assessment followed by intubation was then performed. | Sensitivity, specificity and AUROC of the following: Distance from skin to hyoid bone; Distance from skin to vocal cord; Distance from skin to thyrohyoid membrane | All parameters can act as a tool for predicting difficult intubation with distance from skin to thyrohyoid membrane being the single best parameter (sensitivity: 100%, specificity: 91.9%). | This was a single centre study with participants being chosen by convenience sampling. CL grade IIb was classified as a difficult airway which differs from the criteria in the other studies. Some patient populations were excluded, such as those with facial/neck trauma, pregnant patients, known airway pathologies. |
| “Unlocking Airway Predictability: The Role of Ultrasound in Assessing Cormack-Lehane Grade Through Anterior Neck Soft Tissue Thickness at the Level of Vocal Cords and Hyoid Bone” Krishnamoorthy, D. G., Devendra Prasad, K. J., Rajesh, K., Nikhil Reddy, Y., & Aravind, S. R.R March 24, 2025 India | Adults who presented to the ED requiring intubation. N=100, mean age: 45.2, males: 85%. | A 6-13MHz linear probe was used whilst the patient was in a sniffing position. CL grading assessment followed by intubation was then performed. | Sensitivity, specificity and AUROC of the following: Distance from skin to hyoid bone; Distance from skin to vocal cord | All parameters can act as a tool for predicting difficult intubation with distance from skin to vocal cord being the single best parameter (sensitivity: 90.3%, specificity: 95.7%). | This was a single centre study. Some patient populations were excluded such as patients with cervical spine pathology and pregnant women. There was a low prevalence of difficult intubations in the sample. |
Author Commentary:
In summary, certain parameters provided good diagnostic information and demonstrate clinical usability in predicting difficult airway intubations. Among these parameters, the distance from skin to thyrohyoid membrane demonstrated the highest diagnostic accuracy.
Both sensitivity and specificity are important in any clinical test used for diagnostic purposes. In scenarios where there is a false positive in predicting a difficult airway with POCUS, there may be a negative impact on healthcare systems, as additional resources could be allocated
unnecessarily due to the suspected difficult airway. However, a false negative can have catastrophic consequences, as a difficult airway may go unrecognised and not be escalated promptly. This could result in the failure to prepare necessary adjuncts such as advanced laryngoscopes and a lack of readiness for a 'can’t intubate, can’t ventilate' scenario. Such situations can lead to patient desaturation and, in severe cases, death.
Based on the results illustrated above, most parameters demonstrate fair to considerable diagnostic accuracy in terms of sensitivity and specificity, with only the distance from the skin to the thyrohyoid membrane showing excellent diagnostic accuracy. This suggests that POCUS alone may lead to missed identification of difficult airways and, therefore, should not be relied upon as a standalone tool for airway prediction. Furthermore, POCUS is operator-dependent, meaning that variability in sensitivity may be attributed to the level of experience and training of the operator. Instead, POCUS should be used alongside other airway assessment techniques to improve the likelihood of identifying a difficult airway.
A key limitation in our review is that none of the 4 studies recorded first-pass success rates, which is an important outcome for illustrating the true difficulty of intubation. Instead, the studies rely on the CL classification, which does not necessarily equate to a difficult airway but serves as a surrogate reference. Mallampati classification was also not considered by any study. In addition, the majority of participants across all 4 studies were male. This imbalance in gender representation introduces uncertainty regarding the effectiveness of POCUS in predicting difficult airways in female patients due to their anatomical differences. Finally, our review only included a small number of studies, creating potential for a single study with flawed methodology to disproportionately influence the overall findings.
Therefore, future research should focus on using sample sizes with more females, as well as taking into consideration the first-pass success rate and Mallampati classification to enable an even more comprehensive analysis. Based on our review, we recommend that POCUS should be used alongside other airway techniques to identify difficult airway intubation.
Both sensitivity and specificity are important in any clinical test used for diagnostic purposes. In scenarios where there is a false positive in predicting a difficult airway with POCUS, there may be a negative impact on healthcare systems, as additional resources could be allocated
unnecessarily due to the suspected difficult airway. However, a false negative can have catastrophic consequences, as a difficult airway may go unrecognised and not be escalated promptly. This could result in the failure to prepare necessary adjuncts such as advanced laryngoscopes and a lack of readiness for a 'can’t intubate, can’t ventilate' scenario. Such situations can lead to patient desaturation and, in severe cases, death.
Based on the results illustrated above, most parameters demonstrate fair to considerable diagnostic accuracy in terms of sensitivity and specificity, with only the distance from the skin to the thyrohyoid membrane showing excellent diagnostic accuracy. This suggests that POCUS alone may lead to missed identification of difficult airways and, therefore, should not be relied upon as a standalone tool for airway prediction. Furthermore, POCUS is operator-dependent, meaning that variability in sensitivity may be attributed to the level of experience and training of the operator. Instead, POCUS should be used alongside other airway assessment techniques to improve the likelihood of identifying a difficult airway.
A key limitation in our review is that none of the 4 studies recorded first-pass success rates, which is an important outcome for illustrating the true difficulty of intubation. Instead, the studies rely on the CL classification, which does not necessarily equate to a difficult airway but serves as a surrogate reference. Mallampati classification was also not considered by any study. In addition, the majority of participants across all 4 studies were male. This imbalance in gender representation introduces uncertainty regarding the effectiveness of POCUS in predicting difficult airways in female patients due to their anatomical differences. Finally, our review only included a small number of studies, creating potential for a single study with flawed methodology to disproportionately influence the overall findings.
Therefore, future research should focus on using sample sizes with more females, as well as taking into consideration the first-pass success rate and Mallampati classification to enable an even more comprehensive analysis. Based on our review, we recommend that POCUS should be used alongside other airway techniques to identify difficult airway intubation.
Bottom Line:
In patient presenting to ED who require intubation, POCUS may be used alongside established assessment tools to predict difficult airway intubations in a timely manner. However, further research focusing on multiple classification systems is required to determinately answer this clinical question.
Level of Evidence:
Level 3: Small numbers of small studies or great heterogeneity or very different population
References:
- Aadya Pillai, Poonam Arora, Ankita Kabi, Udit Chauhan, Reshma Asokan, P. Akhil, Takshak Shankar, D. J. Lalneiruol, Himanshi Baid & Hannah Chawang. The diagnostic accuracy of point-of-care ultrasound parameters for airway assessment in patients undergoing intubation in emergency department—an observational study
- Mehran Sotoodehnia, Maryam Khodayar, Alireza Jalali, Mehdi Momeni, Arash Safaie & Atefeh Abdollahi. Prediction of difficult laryngoscopy / difficult intubation cases using upper airway ultrasound measurements in emergency department: a prospective observational study
- Srinivasarangan, Madhu; Akkamahadevi, P.; Balkal, Veeresh C.; Javali, Rameshbabu Homanna. Diagnostic Accuracy of Ultrasound Measurements of Anterior Neck Soft Tissue in Determining a Difficult Airway
- Krishnamoorthy, D. G., Devendra Prasad, K. J., Rajesh, K., Nikhil Reddy, Y., & Aravind, S. R.R. “Unlocking Airway Predictability: The Role of Ultrasound in Assessing Cormack-Lehane Grade Through Anterior Neck Soft Tissue Thickness at the Level of Vocal Cords and Hyoid Bone”