Abstract
Background:
The airway of an anesthetized patient should be secured with an artificial airway for oxygenation or ventilation. Pediatrics are not small adults which means they are different from adults both anatomically and physiologically. This study aims to determine the prevalence of difficult airway and its associated factors in pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
Methods:
A multi-centered cross-sectional study design was employed. The bivariable and multivariable logistic regression was used to measure the association between the dependent variable (pediatrics difficult airway) and independent variables. p-value < 0.05 was used to declare statistical significance.
Results:
A total of 290 pediatrics patients were included in this study. The prevalence of difficult airway in pediatrics patients who underwent surgery was 19.7%. In multivariate logistic regression, pediatrics patients less than 2 years of age (adjusted odds ratio = 6.768, 95% confidence interval = 2.024, 22.636), underweight pediatrics patients (adjusted odds ratio = 4.661, 95% confidence interval = 1.196, 18.154), pediatrics patients having anticipated difficult airway (adjusted odds ratio = 18.563, 95% confidence interval = 4.837, 71.248), history of the difficult airway (adjusted odds ratio = 8.351, 95% confidence interval = 2.033, 34.302), the experience of anesthetists less than 4 years of age (adjusted odds ratio = 9.652, 95% confidence interval = 2.910, 32.050) had a significant association with pediatrics difficult airway.
Conclusion:
Being pediatric patients less than 2 years of age, underweight pediatrics patients, having anticipated difficult airway, those anesthetists who do not perform enough pediatric cases were identified as the main factors associated with the greater occurrence of difficult airway in pediatric patients.
Keywords: Pediatrics, difficult airway, general anesthesia
Introduction
One of the tasks of an anesthetist is securing the airway of patients with an artificial means that involves mask ventilation (MV) and endotracheal intubation.1–3 The difficult airway is one of the most common complications of the airway. Hypoxia, esophageal intubation, and difficult endotracheal intubation (DETI) are the reasons for problems with the airway. Around 17% of the respiratory-related problems resulted from difficult intubation, and about 28% of all anesthesia-related mortality is due to difficult intubation or ventilation. 1
Pediatrics have a large tongue, large head, anterior larynx, smallmouth, narrow airway, and low functional residual capacity, and they are hard to intubate.3–8 MV, direct laryngoscopy, and endotracheal intubation could be relatively difficult in pediatric patients.
A patent and secure airway is needed to manage anesthetized or critically ill patients. 9 Different kinds of literature show that pediatrics cannot tolerate a period of hypoxia when compared to adults. When they are hypoxic, they will be bradycardic and might develop cardiac arrest. Difficulty in securing the airway of pediatric patients is not uncommon in anesthesia practice and results in morbidity and mortality of patients.10–14
Assessing the airway parameters like the oropharyngeal view, thyromental distance, hyomental distance, or other predictors of difficult airway in pediatrics patients is difficult in managing difficult airway case scenarios.13,15–17 Studies regarding difficult airways in pediatric patients were not established well in developing countries like Ethiopia. Therefore, this study aims to determine the prevalence of difficult airway and its associated factors in pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
Methods
Study design, setting, and participants
This is a multi-centered cross-sectional study was conducted in referral hospitals of Addis Ababa. There are 13 governmental hospitals, from which pediatric surgical procedures are done in 12 hospitals. This study was conducted in five government hospitals (Tikur Anbessa Comprehensive Specialized Hospital, Zewditu Memorial Hospital, Yekatit 12 Hospital Medical College, Minilik II Hospital, and St. Peter Hospital). The study participants were pediatric patients who underwent elective surgical procedures under general anesthesia from 30 December 2019 to 30 March 2020. This study is reported in line with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist 18 and registered at www.researchregistry.com with Research Registry UIN: researchregistry6269.
Inclusion/exclusion criteria
The pediatric patients falling in the classification of American Society of Anesthesiologists (ASA) class I and II; elective surgical procedures; pediatrics patients who require endotracheal intubation; age 0–5 years were included in this study while pediatric patients undergoing surgical procedures under endotracheal intubation under indirect laryngoscopy technique; and pediatric patients whose airway were secured with anesthesia students were excluded.
Sample size and sampling procedure
The sample size was determined using finite population correction formula by assuming the prevalence as 0.5 (since no previous study of similar setup); 5% margin of error; 95% confidence interval (CI); and 10% non-response rate, and therefore, a total sample size of 290 elective surgical patients have participated in this study. A stratified random sampling technique was used to get the required sample size during the study period. The daily operation schedule list was used as a sampling frame. A situational analysis and logbook review showed that during a 3-month period, 300 elective pediatric surgeries are done in Tikur Anbessa Comprehensive Specialized Hospital, 144 in Zewditu Memorial Hospital, 144 in Yekatit 12 Hospital Medical College, 180 in Minilik Hospital, and 72 in St. Peter Hospital. So during the study period, a total of 840 pediatric patients underwent elective surgery. Since the calculated sample size is 290 (n), to find k, we divide 840 (N) by 290 (n) is 2.9. When we divide the total pediatric elective surgery in 3 months by 2.9, we will have (300/2.9) = 103 elective pediatric patients undergoing surgery at Tikur Anbessa Comprehensive Specialized Hospital, 144/2.9 = 50 in Zewditu Memorial Hospital, similarly 50 in Yekatit 12 Hospital Medical College, 180/2.9 = 62 in Minilik Hospital, and 72/2.9 = 25 in St. Peter Hospital. The first patient was chosen by lottery method, and then every third patient was chosen for the study.
Data collection technique
Data were collected, and a structured questionnaire was prepared and pretested on 5% (15 patients) of the sample size. Elective pediatric patients scheduled for surgery under general anesthesia requiring endotracheal intubation were assessed at the waiting room by the trained data collectors immediately before they entered the operation room. Then, each patient who underwent endotracheal intubation was observed for difficult intubation, difficult laryngoscopy (DL), and difficult MV in the operation room. The Cormack and Lehane’s laryngoscopy grade of the patient was determined by the anesthetist who performed the laryngoscopy as well as training was given for the data collectors about the Intubation Difficulty Scale Score (IDSS). An observational data collection technique was used in this study. Han’s scale 19 for MV was used for assessing difficult MV.
Operational definitions
Difficult airway: an experienced anesthetist encounters difficulty with any or all of face MV, laryngoscopy, and tracheal intubation during securing the airway with an endotracheal tube for surgical procedures. 20
Difficult face MV: the Han MV Grade III or Grade IV (Grade III—difficult ventilation (inadequate, unstable, or requiring two providers) with or without muscle relaxant and Grade IV—unable to mask ventilate with or without muscle relaxant). 19
DL: the presence of the Cormack and Lehane Grade III or IV (Grade III—visualization of the only epiglottis and Grade IV—visualization of just the soft palate). 21
Difficult tracheal intubation: IDSS of greater than 5 (IDSS score of greater than 5 has a moderate to major difficulty). 22
Data analysis
Data were entered into Epi-info version 7, and then exported to SPSS version 22 for analysis. All independent variables were analyzed using binary logistic regression with the dependent variable, difficult airway, and those with a p-value of <0.2 from the bivariable analysis were fitted to a multivariate logistic regression to check their association with a difficult airway. The odds ratio, 95% CI, and p-value were computed to identify associated factors and to determine the strength of the association. The p-values of <0.05 were considered to be statistically significant. The Hosmer–Lemeshow test of goodness of fit was performed to check the appropriateness of the analysis model.
Data quality control
To assure the quality of data, training on the objectives and relevance of the study, and brief orientations on the assessment tools were provided for data collectors. A pretest was done before data collection for its accuracy, clarity, and consistency. During data collection, each questionnaire was revised by the investigator for being complete and appropriate.
Ethics approval and informed consent
Ethical clearance and a letter of permission to conduct were obtained from Addis Ababa University Ethical review board. Informed written consent was secured from every study participant’s guardians who have legally authorized representatives of pediatrics patients. Confidentiality and anonymity were ensured.
Results
Demographic characteristics of study participants
A total of 290 pediatric patients who underwent surgical procedures under general anesthesia and endotracheal intubation were included in this study. The mean weight was 8.8 kg with a standard deviation of 4.5 kg. From the total sample, 64.8% were male, and 61.4% of patients were underweight (Table 1).
Table 1.
Demographic characteristics of pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
| Variables | Frequency | Percentage (%) | |
|---|---|---|---|
| Sex | Male | 188 | 64.8% |
| Female | 102 | 35.2% | |
| Age in years | 0–2 | 174 | 60% |
| 3–5 | 116 | 40% | |
| ASA physical status | ASA I | 161 | 55.5% |
| ASA II | 129 | 44.5% | |
| Weight | Normal (BMI is ⩾5th and <85th percentile) | 112 | 38.6% |
| Under (<5th percentile) | 178 | 61.4% | |
ASA: American Society of Anesthesiologists; BMI: body mass index.
Prevalence of difficult intubation, DL, difficult MV, and difficult airway
In this study, we found the prevalence of difficult intubation as 32/290 (11%), DL as 21/290 (7.2%), difficult MV as 16/290 (5.5%), and difficult airway as 57/290 (19.7%).
We found that IDSS was easy on 119/290 (41%), slight difficulty on 139/290 (47.9%), and moderate to major difficulty on 32/290 (11%) of pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa. The majority (69.7%) of pediatrics patients had the Cormack and Lehane Grade of Laryngoscopy (CLGL) I, 23.1% of pediatrics patients had the CLGL II, and 7.2 of pediatrics patients had the CLGL III. This study showed that the HAN MV Grade I, II, and III were 92.4% versus 82.4%, 2.1% versus 11.4%, and 5.5% versus 6.2% before and after muscle relaxant was administered, respectively.
Anesthesia and surgery-related variables
An excessive gas leak was observed in 6.2% of patients, and 17.9% of patients required more than two persons to ventilate (Table 2).
Table 2.
Factors related to mask ventilation of pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
| Variable | Difficult mask ventilation |
Frequency (%) | ||
|---|---|---|---|---|
| Yes | No | |||
| Excessive gas leak | Yes | 8 | 10 | 18 (6.2%) |
| No | 8 | 264 | 272 (93.8%) | |
| Require more than one person to ventilate | Yes | 13 | 39 | 52 (17.9%) |
| No | 3 | 235 | 238 (82.1%) | |
| Jaw thrust | Yes | 12 | 228 | 240 (82.8%) |
| No | 4 | 46 | 50 (17.2%) | |
| Oral airway | Yes | 14 | 18 | 32 (11%) |
| No | 2 | 256 | 258 (89%) | |
| Desaturation | Yes | 12 | 0 | 12 (4.1%) |
| No | 4 | 0 | 4 (1.4%) | |
For this study, the number of laryngoscopies was done in 67.93% of the patients, and the Miller-type laryngoscope blade was used in 15.17% of the study participants (Table 3).
Table 3.
Laryngoscope-related factors of pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
| Variables | Difficult laryngoscopy |
Frequency (%) | ||
|---|---|---|---|---|
| Yes | No | |||
| Number of laryngoscopy attempts | Single | 14 | 183 | 197 (67.93%) |
| Multiple | 7 | 86 | 93 (32.0%) | |
| External laryngeal pressure | Applied | 21 | 168 | 189 (65.17%) |
| Not applied | 101 | 0 | 101 (34.83%) | |
| Type of laryngoscope blade | Miller | 4 | 40 | 44 (15.17%) |
| Macintosh | 17 | 229 | 246 (84.83%) | |
For this study, the original endotracheal tube was changed in 29.3% of patients. The cuffed endotracheal tube was used in 23.8%, and intubation attempt was single in about 81% of the patients (Table 4).
Table 4.
Endotracheal intubation-related factors of pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
| Variables | Difficult intubation | Frequency (%) | ||
|---|---|---|---|---|
| Yes | No | |||
| Changing the original endotracheal tube | Yes | 7 | 78 | 85 (29.31%) |
| No | 25 | 180 | 205 (70.67%) | |
| Type of endotracheal tube | Cuffed | 1 | 68 | 69 (23.79%) |
| Uncuffed | 31 | 190 | 221 (76.21%) | |
| No | 32 | 199 | 231 (79.66%) | |
| Number of intubation attempts | Single | 24 | 211 | 235 (81.03%) |
| 2 | 8 | 34 | 42 (14.48%) | |
| 3 | 0 | 13 | 13 (4.48%) | |
| Type of induction | Inhalational | 41 | 183 | 224 (77.24%) |
| Intravenous | 16 | 50 | 66 (22.76%) | |
| Number of intubation attempts | 1 | 24 | 161 | 185 (63.79%) |
| 2 | 8 | 62 | 70 (24.14%) | |
| 3 | 0 | 35 | 35 (12.07%) | |
| Use of stylet | Used | 13 | 133 | 146 (50.34%) |
| Not used | 19 | 125 | 144 (49.65%) | |
In this study, 100 (34.48%) patients were undergone general surgery, 103 (35.52%) patients were undergone maxillofacial surgery, and 87 (30%) patients were undergone neurosurgery.
Factors associated with difficult airway
In multivariable logistic regression, pediatrics patients age of 0–2 years (adjusted odds ratio (AOR) = 6.768, 95% CI = 2.024, 22.636); underweight pediatrics patients (AOR = 4.661, 95% CI = 1.196, 18.154); pediatrics patients having anticipated difficult airway (AOR = 18.563, 95% CI = 4.837, 71.248); pediatrics patients having a history of the difficult airway (AOR = 8.351, 95% CI = 2.033, 34.302); anesthetist who are working less than 4 years (AOR = 9.652, 95% CI = 2.910, 32.015) were found to be associated with pediatrics patients difficult airway (Table 5).
Table 5.
Factors associated with the difficult airway of pediatric patients who underwent surgery under general anesthesia in referral hospitals of Addis Ababa.
| Variables | Difficult airway |
Unadjusted OR (95% CI) | AOR (95% CI) | p-value | ||
|---|---|---|---|---|---|---|
| Yes | No | |||||
| Age | 0–2 years | 46/174 | 128/174 | 3.430 (1.692, 6.954) | 6.768 (2.024, 22.636) | 0.002 |
| 3–5 years | 11/116 | 105/116 | 1 | 1 | ||
| Weight for age | Normal weight | 13/112 | 99/112 | 1 | 1 | 0.027 |
| Underweight | 44/178 | 134/178 | 2.501 (1.278, 4.892) | 4.661 (1.196, 18.154) | ||
| Anticipated difficult airway | Yes | 41/60 | 19/60 | 28.862 (13.712, 60.751) | 18.563 (4.837, 71.248) | <0.001 |
| No | 16/230 | 214/230 | 1 | 1 | ||
| History of difficult airway | Yes | 38/46 | 8/46 | 56.250 (22.991, 137.524) | 8.351 (2.033, 34.302) | 0.003 |
| No | 19/244 | 225/244 | 1 | 1 | ||
| Experience of the anesthetist | >4 years | 6/163 | 157/163 | 1 | 1 | <0.001 |
| <4 years | 51 | 76 | 17.559 (7.217, 42.722) | 9.652 (2.910, 32.050) | ||
OR: odds ratio; CI: confidence interval; AOR: adjusted odds ratio.
Discussion
Pediatrics patients have relatively more difficult MV, direct laryngoscopy, and endotracheal intubation as compared to adults.7,23,24 The intubation difficult scale is a blend of subjective and objective criteria that permit a qualitative and quantitative approach to the progressive nature of the difficulty of intubation. 25
On day-to-day practice, we have used endotracheal tubes of an appropriate size determined by calculation for pediatric patients who underwent surgery.26,27 However, most Ethiopian children are underweight, and we usually use tubes smaller than the actual calculated endotracheal tubes.
In this study, we found that the prevalence of difficult airway was 19.7% and DL was 7.2%, in pediatric patients who underwent surgical procedures at Addis Ababa Referral Hospitals, which is higher than in other studies that the incidences of DL were 4.77%, 28 1.3%, 29 1.37%, 30 2.95%, 31 4%, 32 and 3%. 33
This study reveals that the incidence of difficult MV was 5.5%. Similarly, El-Orbany and Woehlck 34 reported that the incidence of difficult MV varies widely from 0.5% to 15%. In another study which is conducted on patients between 0 and 8 years, the incidence of difficult bag-MV was 6.6%. 35 In a study done in India on pediatric patients age 1–5 years, the incidence of difficult MV was 3%, and similarly to our finding, the grade of difficult MV had improved after relaxant was given. 36
We found that the incidence of difficult intubation was 11%, which is higher compared to other studies conducted in infants at Osaka City General Hospital 2.4%, 9 and in Canada at the Hospital for Sick showed that 0.5% of pediatrics patients had difficult intubation. 37
This study showed that small age (0–2 years), underweight children, anticipated difficult airway from history and physical examination, children who had difficult airway history, and anesthesiologists who do not perform enough pediatric cases also will have difficulties in managing difficult airway (less than 4 years of experience) had a significant association with a difficult airway. In line with our finding, a study done in the pediatric intensive care unit showed that a history of difficult airways and less experienced providers were associated with difficult airways. 38 Studies showed that there was a significant association between small age and difficult airway.30,31,36 The main limitation of this study is it only focuses on the prevalence of difficult airway in pediatrics age groups other than other surgical patients that could have difficulties in securing the airway.
Conclusion
The prevalence of difficult airway in pediatric patients who underwent surgery was high. Pediatric patients less than or equal to 2 years, who are underweight, those who had a history of difficult airway and anticipated difficult airway, and those anesthetists who do not perform enough pediatric cases were identified as the main factors associated with the greater occurrence of difficult airway in pediatrics patients.
Supplemental Material
Supplemental material, sj-docx-1-smo-10.1177_20503121211052436 for The prevalence of difficult airway and its associated factors in pediatric patients who underwent surgery under general anesthesia: An observational study by Eleni Amaha, Lydia Haddis, Senait Aweke and Efrem Fenta in SAGE Open Medicine
Supplemental material, sj-docx-2-smo-10.1177_20503121211052436 for The prevalence of difficult airway and its associated factors in pediatric patients who underwent surgery under general anesthesia: An observational study by Eleni Amaha, Lydia Haddis, Senait Aweke and Efrem Fenta in SAGE Open Medicine
Acknowledgments
The authors acknowledge the Addis Ababa University.
Footnotes
Author contributions: EA, LH, SA, and EF were involved in the data collection, data analysis, and manuscript preparation. All authors agree, read, and verify the manuscript for publication.
Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical approval: Ethical approval for this study was obtained from the Addis Ababa University Ethical Review board with the Ethical Approval no. 10/19/Anes.
Funding: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was funded by the Addis Ababa University.
Informed consent: Informed written consent was secured from every study participant guardians who were legally authorized representative of pediatrics patients.
ORCID iD: Efrem Fenta 
https://orcid.org/0000-0001-9709-8718
Data sharing statement: Data will be shared upon reasonable request.
Supplemental material: Supplemental material for this article is available online.
References
- 1. Collins SR. Direct and indirect laryngoscopy: equipment and techniques discussion. Respir Care 2014; 59(6): 850–864. [DOI] [PubMed] [Google Scholar]
- 2. Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2013; 118(2): 251–270. [DOI] [PubMed] [Google Scholar]
- 3. Casey JD, Semler MW, High K, et al. How I manage a difficult intubation. Crit Care 2019; 23: 177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Rivera-Tocancipá D, Díaz-Sánchez E. Pediatric airway: as difficult as they say? Rev Colomb Anestesiol 2018; 46: 52–57. [Google Scholar]
- 5. Raj D, Luginbuehl I. Managing the difficult airway in the syndromic child. Contin Educ Anaesth Crit Care Pain 2015; 15(1): 7–13. [Google Scholar]
- 6. Popovici S-E, Mitre C. Difficult airway management—a constant challenge. Rom J Anaesth Intensive Care 2018; 25(2): 93–94. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Krishna SG, Bryant JF, Tobias JD. Management of the difficult airway in the pediatric patient. J Pediatr Intensive Care 2018; 7(3): 115–125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Walas W, Aleksandrowicz D, Kornacka M, et al. The management of unanticipated difficult airways in children of all age groups in anaesthetic practice—the position paper of an expert panel. Scand J Trauma Resusc Emerg Med 2019; 27(1): 87. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Aida J, Oda Y, Kasagi Y, et al. The management of difficult intubation in infants: a retrospective review of anesthesia record database. JA Clin Rep 2015; 1(1): 18. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Adewale L. Anatomy and assessment of the pediatric airway. Paediatr Anaesth 2009; 19(Suppl. 1): 1–8. [DOI] [PubMed] [Google Scholar]
- 11. Dickison A. The normal and abnormal pediatric upper airway. Recognition and management of obstruction. Clin Chest Med 1987; 8(4): 583–596. [PubMed] [Google Scholar]
- 12. Mathew P, Ashok V, Siraj M, et al. Validation of age and height based formulae to predict paediatric airway distances —a prospective observational study. J Postgrad Med 2019; 65(3): 164–168. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Huang AS, Hajduk J, Rim C, et al. Focused review on management of the difficult paediatric airway. Indian J Anaesth 2019; 63(6): 428–436. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Cook T, MacDougall-Davis SR. Complications and failure of airway management. Br J Anaesth 2012; 109(Suppl. 1): i68–i85. [DOI] [PubMed] [Google Scholar]
- 15. Gupta S, Sharma R, Jain D. Airway assessment: predictors of difficult airway. Indian J Anaesth 2005; 49(4): 257–262. [Google Scholar]
- 16. Workeneh SA, Gebregzi AH, Denu ZA. Magnitude and predisposing factors of difficult airway during induction of general anaesthesia. Anesthesiol Res Pract 2017; 2017: 5836397. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17. Tamire T, Demelash H, Admasu W. Predictive values of preoperative tests for difficult laryngoscopy and intubation in adult patients at Tikur Anbessa Specialized Hospital. Anesthesiol Res Pract 2019; 2019: 1790413. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18. Knottnerus A, Tugwell P. STROBE—a checklist to Strengthen the Reporting of Observational Studies in Epidemiology. J Clin Epidemiol 2008; 61(4): 323. [DOI] [PubMed] [Google Scholar]
- 19. Langeron O, Masso E, Huraux C, et al. Prediction of difficult mask ventilation. Anesthesiology 2000; 92(5): 1229–1236. [DOI] [PubMed] [Google Scholar]
- 20. Petrini F, Accorsi A, Adrario E, et al. Recommendations for airway control and difficult airway management. Minerva Anestesiol 2005; 71(11): 617–657. [PubMed] [Google Scholar]
- 21. Yentis S, Lee D. Evaluation of an improved scoring system for the grading of direct laryngoscopy. Anaesthesia 1998; 53(11): 1041–1044. [DOI] [PubMed] [Google Scholar]
- 22. Iohom G, Ronayne M, Cunningham A. Prediction of difficult tracheal intubation. Eur J Anaesthesiol 2003; 20(1): 31–36. [DOI] [PubMed] [Google Scholar]
- 23. Huang AS, Rutland L, Hajduk J, et al. Difficult airway management of children in ambulatory anesthesia: challenges and solutions. Ambul Anesth 2016; 3: 37–45. [Google Scholar]
- 24. Chambers N, Ramgolam A, Sommerfield D, et al. Cuffed vs. uncuffed tracheal tubes in children: a randomised controlled trial comparing leak, tidal volume and complications. Anaesthesia 2018; 73(2): 160–168. [DOI] [PubMed] [Google Scholar]
- 25. Seo S-H, Lee J-G, Yu S-B, et al. Predictors of difficult intubation defined by the intubation difficulty scale (IDS): predictive value of 7 airway assessment factors. Korean J Anesthesiol 2012; 63(6): 491–497. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26. Hanamoto H, Maegawa H, Inoue M, et al. Age-based prediction of uncuffed tracheal tube size in children to prevent inappropriately large tube selection: a retrospective analysis. BMC Anesthesiol 2019; 19(1): 141. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27. Tinning K, Acworth J. Make your Best Guess: an updated method for paediatric weight estimation in emergencies. Emerg Med Australas 2007; 19(6): 528–534. [DOI] [PubMed] [Google Scholar]
- 28. Xue F, Zhang G, Li P, et al. The clinical observation of difficult laryngoscopy and difficult intubation in infants with cleft lip and palate. Paediatr Anaesth 2006; 16(3): 283–289. [DOI] [PubMed] [Google Scholar]
- 29. Heinrich S, Birkholz T, Ihmsen H, et al. Incidence and predictors of difficult laryngoscopy in 11.219 pediatric anesthesia procedures. Paediatr Anaesth 2012; 22(8): 729–736. [DOI] [PubMed] [Google Scholar]
- 30. Baker PA. Assessment and management of the predicted difficult airway in babies and children. Anaesth Intensive Care Med 2019; 20(1): 42–51. [Google Scholar]
- 31. Gunawardana R. Difficult laryngoscopy in cleft lip and palate surgery. Br J Anaesth 1996; 76(6): 757–759. [DOI] [PubMed] [Google Scholar]
- 32. Aparna D, Jafra A, Bhardwaj N, et al. Evaluation of various anthropometric airway parameters as predictors of difficult airway in neonates: a prospective observational study. Int J Pediatr Otorhinolaryngol 2020; 138: 110387. [DOI] [PubMed] [Google Scholar]
- 33. Mirghassemi A, Soltani AE, Abtahi M. Evaluation of laryngoscopic views and related influencing factors in a pediatric population. Paediatr Anaesth 2011; 21(6): 663–667. [DOI] [PubMed] [Google Scholar]
- 34. El-Orbany M, Woehlck HJ. Difficult mask ventilation. Anesth Analg 2009; 109(6): 1870–1880. [DOI] [PubMed] [Google Scholar]
- 35. Valois-Gómez T, Oofuvong M, Auer G, et al. Incidence of difficult bag-mask ventilation in children: a prospective observational study. Paediatr Anaesth 2013; 23(10): 920–926. [DOI] [PubMed] [Google Scholar]
- 36. Aggarwal A, Sharma K, Verma U. Evaluation of difficult Airway predictors in pediatric population as a clinical investigation. J Anesth Clin Res 2012; 3(11): 1–5. [Google Scholar]
- 37. Karsli C, Pehora C, Al-Izzi A, et al. A retrospective review of pediatric difficult airways: once easy, not always easy. Can J Anaesthesia/J can d’anesth 2016; 63(6): 776–777. [DOI] [PubMed] [Google Scholar]
- 38. Graciano AL, Tamburro R, Thompson AE, et al. Incidence and associated factors of difficult tracheal intubations in pediatric ICUs: a report from National Emergency Airway Registry for Children: NEAR4KIDS. Intensive Care Med 2014; 40(11): 1659–1669. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplemental material, sj-docx-1-smo-10.1177_20503121211052436 for The prevalence of difficult airway and its associated factors in pediatric patients who underwent surgery under general anesthesia: An observational study by Eleni Amaha, Lydia Haddis, Senait Aweke and Efrem Fenta in SAGE Open Medicine
Supplemental material, sj-docx-2-smo-10.1177_20503121211052436 for The prevalence of difficult airway and its associated factors in pediatric patients who underwent surgery under general anesthesia: An observational study by Eleni Amaha, Lydia Haddis, Senait Aweke and Efrem Fenta in SAGE Open Medicine