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Abstract

Lingual tonsillar hypertrophy is rarely identified on routine airway assessment but may cause difficulties in airway management. We conducted a narrative review of case reports of lingual tonsillar hypertrophy to examine associated patient factors, success rates of airway management techniques and complications. We searched the literature for anaesthetic management of cases with lingual tonsillar hypertrophy. We found 89 patients in various case reports, from which we derived 92 cases to analyse. 64% of cases were assessed as having a normal airway. Difficult and impossible face mask ventilation occurred in 29.6% and 1.4% of cases, respectively. Difficult intubation and failed intubation occurred in 89.1% and 21.7% of cases, respectively. Multiple attempts (up to six) at intubation were performed, with no successful intubation after the third attempt with direct laryngoscopy. Some 16.5% of patients were woken up and 4.3% required emergency front of neck access. Complications included oesophageal intubation (10.9%), bleeding (9.8%) and severe hypoxia (3.2%). Our findings show that severe cases of lingual hypertrophy may cause an unanticipated difficult airway and serious complications, including hypoxic brain damage and death. A robust airway strategy is required which includes limiting the number of attempts at laryngoscopy, and early priming and performance of emergency front of neck access if required. In patients with known severe lingual tonsillar hypertrophy, awake intubation should be considered.

Keywords

Airway obstruction complications intubation laryngoscopy lingual tonsillar hypertrophy

Introduction

The lingual tonsils are located at the base of the tongue, and ‘although out of sight … should not be out of mind’.¹ They are part of Waldeyer’s ring of lymphoid tissue, and sit at the base of the tongue between the epiglottis posteriorly, the circumvallate papilla anteriorly and tonsillar pillars laterally.^1,2 Lingual tonsillar hypertrophy (LTH) occurs in 0.3–3% of surgical patients.^3
–5 However, one endoscopic study showed clinically meaningful LTH in 14–15%.⁶ In the classification system of Friedman et al., clinically meaningful LTH includes lymphoid tissue classed as grade 3 (covering the entire tongue base with a vertical thickness of 5–10 mm) or grade 4 (covering the entire tongue base with a vertical thickness of approximately 1 cm, rising above the tip of the epiglottis).⁷ A flexible nasendoscopic view of LTH is shown in Figure 1. The aetiology of LTH is unclear but it is associated with an elevated body mass index (BMI) and gastro-oesophageal reflux.⁸

Figure 1.

Flexible nasendoscopy of a patient with lingual tonsillar hypertrophy occupying the tongue base. E: epiglottis; LTH: lingual tonsillar hypertrophy.

LTH may be associated with hypoxia, oropharyngeal trauma, oesophageal intubation, cardiac arrest, and death.^2,9 As such, the aims of our review are to obtain a detailed understanding of LTH, the success rates of various airway techniques, and the airway difficulties and complications associated with significant LTH. We also investigate the mechanism of failure of various airway techniques in relation to LTH. These may aid with decision making, choosing the optimal airway strategy, and minimising patient morbidity.

Methods

We performed a search of the literature reporting anaesthetic management of adult patients with LTH, and describe the patient characteristics, airway techniques used, and their outcomes and complications. We searched PubMed, Google Scholar and Google for relevant adult case reports relating to the anaesthetic airway management of LTH. We used the following keywords: ‘lingual tonsil’, ‘lingual tonsillar hypertrophy’, ‘lingual tonsillar hyperplasia’, ‘lingual tonsil hypertrophy’, ‘lingual tonsil hyperplasia’ combined with ‘anaesthesia’, ‘intubation’, or ‘difficult airway’. The search included all articles until December 2021 and was not limited by language.

We retrieved data on airway assessment including: Mallampati score,¹⁰ mouth opening, thyromental distance,¹¹ head and neck movement, and whether the authors subjectively considered the patient as having a ‘normal airway’ (airway assessment unremarkable or not anticipating a difficult intubation). We collected data on anaesthetic techniques used; if the type of direct laryngoscope was not described, we assumed it was the Macintosh type. Outcome data were collected on airway technique success (e.g. ease of ventilation, laryngoscopic view and intubation success) and complications. Laryngoscopic laryngeal view was graded using the Cormack–Lehane (CL) classification:¹² 1, full view of the vocal cords; 2, only part of the vocal cords or arytenoids seen; 3, epiglottis seen; and 4, no epiglottis seen. We applied this to direct laryngoscopy, videolaryngoscopy and flexible bronchoscopy intubation (FBI) views. If ‘no glottis’ was documented then we classified this as CL grade 3. For data analysis, we grouped CL grades 1 and 2 together so as to include those documented as ‘easy view of the glottis’ (or similar). We defined ‘difficult intubation’ as CL grade 3 or greater, or tracheal intubation requiring threeor more attempts, or failed tracheal intubation.¹² ‘Multiple attempts’ was defined as three or more documented attempts, and severe hypoxia as an arterial saturation (SpO₂) less than 80%.

Each episode that a patient presented for surgery was termed a ‘case’. If, following induction of anaesthesia and failed airway management, a patient was woken up and required a subsequent awake FBI, we termed this a ‘postoperative awake FBI’. We did not count this as an extra case as the scheduled surgery was not performed and we regarded awake FBI as a continuum of the original airway strategy.¹³

For data analysis, the denominator was the total number of patients or cases with recorded data. We defined the ‘overall technique success rate’ as the number of times a technique was used and was ultimately successful = (number of cases a technique was successful)/(number of cases in which the technique was used). However, a given technique may be used multiple times. Accordingly, the ‘attempt success rate’= number of successful attempts/total number of attempts using that technique. For example, direct laryngoscopy may have been used in 10 cases and was successful in four cases but there was a total of 20 attempts. This gives an overall technique success rate of 40% (four out 10 cases) but an attempt success rate of 20% (four out of 20 attempts).

Statistical analysis

Descriptive data are presented as mean (range) for continuous variables, or number (percentages) for categorical variables. Each preoperative airway assessment method was categorised into two groups based on criteria predicting difficult intubation: that is, Mallampati scores 3 or 4;¹⁰ mouth opening less than 4 cm or less than two finger breadths; thyromental distance (<6 cm or less than three finger breadths);¹¹ and moderately or severely limited head and neck movement. The predictive power for each airway assessment was described using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), with their respective 95% confidence intervals (CIs). Confidence intervals for sensitivity and specificity were estimated using the Clopper–Pearson exact method.¹⁴ We used a Fisher’s exact test to determine if there was a statistically significant relationship between predicted and actual successful tracheal intubations. A P value less than 0.05 was considered statistically significant.

Results

We retrieved 48 articles: 34 in English,^{2,5,9,15
–45} nine in Japanese,^46
–54 two in Spanish,^55,56 one in Korean,⁵⁷ one in French,⁵⁸ and one in Italian.⁵⁹ These articles described a total of 89 patients and 92 cases (see Figure 2). One case series by Ovassapian et al. included a total of 33 patients: 27 patients had unanticipated failed direct laryngoscopic intubation followed by successful asleep FBI and six patients had an awake FBI due to their history of unanticipated failed intubation.² Another article reported three patients but we only included one patient due to a lack of data for the others.²¹

Figure 2.

Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) flow chart.

The patient characteristics are presented in Table 1. The mean age, weight and BMI of our patients were 49.3 years, 89.3 kg and 31.2 kg/m², respectively. Some 19.7% of cases had a BMI of 40 kg/m² or greater. In the four cases of severe hypoxia, three had BMI greater than 30 kg/m².^9,28 13.5% of cases had either obstructive sleep apnoea (OSA) or LTH-related symptoms preoperatively: sore throat, dysphagia, globus sensation, speech change, chronic cough, dyspnoea, snoring, choking on food, otalgia and submandibular referred pain;^1,8,9,26 64.0% of LTH patients had a ‘normal airway’ (Table 1). In LTH patients, predictive values of routine airway assessments varied (Table 2): sensitivity 6.0–31.3%; specificity 37.5–100%; PPV 70.6–100%; and NPV 6.8–15.1%.

Table 1.

Patient characteristics and routine airway assessments.

	Value
Number of patients (cases)	89 (92)
Mean age (range) years [n = 86]	49.3 (19–78)
Sex (male: female) [n = 86]	43: 43 (50%: 50%)
Mean weight (range) kg [n = 63]	89.3 (45–182)
Mean BMI kg/m² (range) [n = 66]	31.2 (17.1–64.1)
BMI ≥30 kg/m²	32 (48.5%)
BMI ≥30 to <40 kg/m²	19 (28.8%)
BMI ≥40 kg/m²	13 (19.7%)
Obstructive sleep apnoea	4 (4.5%)*
Obstructive sleep apnoea or LTH associated symptoms	12 (13.5%)*
Previous tonsillectomy	11 (12.4%)*
Previous general anaesthesia	32 (36.0%)*
History of difficult airway	8 (9.0%)*
‘Normal airway’	57 (64.0%)*
‘Routine airway assessment’ all tests normal	38 (42.7%)*
Mallampati score 1/2/3/4 [n = 69]	20/29/19/1 (29.0%/42.0%/27.5%/1.1%)
Mouth opening <4/≥4 cm [n = 54]	7/47 (13.0%/87.0%)
Thyromental distance <6.0/≥6.0 cm [n = 55]	3/52 (5.5%/94.5%)
Neck movement [n = 52] - normal or mild/moderate or severe limitation	37/15 (71.2%/28.8%)

BMI: body mass index; LTH: lingual tonsil hypertrophy; ‘normal airway’: airway assessment unremarkable or not anticipating a difficult intubation by case report/series authors.

*n = 89 patients unless otherwise stated.

Table 2.

Predictive value for difficult intubation for various airway assessment methods (% and 95% confidence interval).

Predictive factor	Sensitivity	Specificity	Positive predictive value	Negative predictive value	Fisher’s exact P value
BMI <30 vs. ≥30 mg/kg²	47.5%(34.3–60.9)	37.5%(8.5–75.5)	86.1%(77.3–91.9)	8.0%(3.3–18.1)	0.476
Mallampati score 1&2 vs. 3&4	25.8%(15.5–38.5)	44.4%(13.7–78.8)	79.2%(64.9–88.7)	6.8%(3.4–13.4)	0.112
Interdental distance <4 vs. ≥4 cm	11.8%(4.4–23.9)	60.0%(14.7–94.7)	70.6%(39.3–89.9)	7.7%(3.9–14.6)	0.144
Thyromental distance <6 vs. ≥6 cm	6.0%(1.3–16.6)	83.3%(35.9–99.6)	74.6%(26.5–96.0)	9.8%(7.0–13.5)	0.373
Neck movement (normal and mild restriction) vs. (moderate and severe restriction)	31.3%(18.6–46.3)	100%(47.8–100)	100%	15.1%(12.8–17.7)	0.306
Obstructive sleep apnoea or LTH symptoms	12.2%(6.0–21.3)	90.0%(55.5–99.8)	90.9%(58.7–98.6)	11.1%(12.9–30.4)	1.000
Tonsillectomy	11.0%(5.1–19.8)	70.0%(34.8–93.3)	74.9%(49.1–90.3)	8.8%(6.0–12.7)	0.120

BMI: body mass index; LTH: lingual tonsil hypertrophy.

Data are derived from a combination of the lingual tonsillar hypertrophy cases.

Based on an incidence of difficult intubation in LTH cases following induction of anaesthesia = 89.1%.

Most (92.4%) LTH cases had attempts at securing their airway after induction of anaesthesia. Four cases had known LTH after preoperative assessment and investigations.^25,45,52,57 Failed airway management resulted in attempts to wake up the patient in 14 (16.5%) cases. Seven (7.6%) LTH cases were anticipated as having a difficult airway and had awake tracheal intubation.

Difficult and impossible face mask ventilation (as defined by the case report authors) in LTH cases occurred in 29.6% and 1.4% of cases, respectively (Table 3). Supraglottic airways provided easy/adequate and difficult ventilation in 72.0% and 20.0% of LTH cases, respectively. Difficult and failed intubation rates occurred in 89.1% and 21.7% of LTH cases, respectively. The overall technique success rates for Macintosh, straight blade and videolaryngoscopy were 15.4%, 20.0% and 50.0%, respectively. However, attempt success rates were lower for the Macintosh and straight blade laryngoscopy: 2.0% and 12.5%, respectively. Macintosh laryngoscopy grades were reported in 65 cases, and CL grades 1 and 2 (combined), grade 3 and grade 4 were obtained in five (7.7%), 35 (53.8%) and 25 (38.5%) cases, respectively. These were associated with decreasing intubation success rates: 80%, 20% and 4%, respectively.

Table 3.

Anaesthetic airway management of lingual tonsillar hypertrophy cases and outcomes of each airway technique.

Technique	Total cases with parameter documented (% of the 92 cases)	Overall technique success rate (number of cases and %)	Attempt success rate (number of cases and %)
Flexible bronchoscopic intubation	Preoperative awake = 6 (6.5%)Asleep = 47 (51.1%)Postoperative awake = 9 (9.8%)	Preoperative awake = 6 (100%)Asleep = 32 (68.1%)Postoperative awake = 8 (88.9%)
Face mask ventilation	71 (77.2%)	Ease of ventilation 49 (69.0%) easy/adequate ventilation 21 (29.6%) difficult ventilation 1 (1.4%) impossible ventilation
Difficult intubation	82 (89.1%)
Failed intubation	20 (21.7%)
Direct laryngoscopy^a	All devices = 78 (84.8%) Macintosh = 78 (84.8%) Straight blade = 10 (10.9%) McCoy = 2 (2.6%)	All devices = 14 (17.9%) Macintosh = 12 (15.4%) Straight blade = 2 (20.0%) McCoy = 0 (0%)	All devices 161 attempts in 50 cases 4 (2.5%) success Macintosh 149 attempts in 49 cases 3 (2.0%) success Straight blade 8 attempts in 5 cases 1 (12.5%) success McCoy 1 attempt in 1 case 0 (0%) success
Indirect laryngoscopy^a	All devices = 9 (9.8%) Videolaryngoscope = 6 (6.5%) Rigid fibreoptic laryngoscope = 3 (3.3%)	All devices = 5 (55.6%) Videolaryngoscope = 3 (50.0%) Rigid fibreoptic laryngoscope = 2 (66.7%)
Supraglottic airway used^a	Total = 26 (28.3%) CTrach= 2 i-gel = 2 ILMA = 7 LMA = 15 ProSeal LMA = 4	Ease of ventilation (n=25) Easy/adequate = 18 (72.0%) Difficult = 5 (20.0%) Impossible 2 (8.0%)	16 attempts in 8 cases
SGI used^a	13 (14.1%) CTrach = 3 i-gel = 2 ILMA = 6 LMA = 4	6 (46.2%) cases successful CTrach = 1 (33.3%) i-gel = 0 (0%) ILMA = 3 (50.0%) LMA = 1 (25.0%)
Patient woken up	14 (16.5%)^b	13 (92.9%)
eFONA	4 (4.3%)	4 (100%)	6 attempts in 4 cases 4 (66.7%) successful

CL: Cormack–Lehane laryngoscopy view; FBI: flexible bronchoscopic intubation; eFONA: emergency front of neck access; ILMA: intubating laryngeal mask airway; LMA: laryngeal mask airway; rigid fibreoptic laryngoscopes: UpsherScope and WuScope; SGI: supraglottic airway guided intubation.

More than one device may have been used.

Out of 85 cases who had induction of anaesthesia before attempts at securing their airways.

Direct laryngoscopy was associated with multiple attempts: one to six attempts were made in four (5.1%), nine (12.8%), 15 (19.2%), 17 (21.8%), four (5.1%) and one (1.3%) cases, respectively. Intubation success rates for one, two and three attempts were 25.0%, 22.2% and 6.7%, respectively. No successful intubations occurred after a third attempt.

FBI under anaesthesia was the technique most often used in LTH cases after failed intubation (51.5%), and had an overall technique success rate of 68.1% (Table 4). Impingement and failure to railroad the tracheal tube occurred in 11 (23.4%) and two (4.3%) cases, respectively. FBI was also performed by way of a supraglottic airway (supraglottic airway guided intubation, SGI)⁶⁰ in 13 (14.1%) cases and had an overall technique success rate of 46.2%.

Table 4.

Success rates of airway techniques in the lingual tonsillar hypertrophy cases compared with those from other difficult airway studies (% and 95% confidence interval).

	Our review of LTH cases	Parmet et al., 1998⁶²	Aziz et al., 2016⁶¹
Macintosh laryngoscopy	15.4%; 95% CI 9–25
Straight blade laryngoscopy	20.0%; 95% CI 5–52
Videolaryngoscopy	50.0%; 95% CI 19–81		92%; 95% CI 71–83
Flexible bronchoscopic intubation	Preoperative awake = 100%; 95% CI 64–100Asleep = 68.1%; 95% CI 54–80Postoperative awake = 88.9%;95% CI 54–100	50%; 95% CI 0–100	78%; 95% CI 71–83
Supraglottic airway	72.0%; 95% CI 52–86^a	94%; 95% CI 77–100
SGI	46.2%; 95% CI 23–71		78%; 95% CI 68–86
eFONA	66.7%; 95% CI 30–91	TTJV 33%; 95% CI 0–100Surgical cricothyroidotomy 100%; 95% CI 37–100

eFONA: emergency front of neck access; LTH: lingual tonsillar hypertrophy; SGI: supraglottic airway guided intubation; TTJV: transtracheal jet ventilation.

For easy/adequate ventilation.

‘Non-standard airway techniques’ were those other than the conventional use of the above airway techniques (supraglottic airway, direct and videolaryngoscopy, FBI and SGI), and were mainly performed after more conventional techniques had failed. They included bougie guided Pro-Seal LMA insertion,²² light wand guided intubation,^24,48 FBI by a stylet guided double lumen tube,³⁹ direct or videolaryngoscopy facilitating FBI,⁵⁷ rigid bronchoscopy,²³ retrograde wire guided intubation,^18,43,47 surgical laryngoscopy,²⁶ and laryngeal tube.³⁷ Further description of these are beyond the scope of this review.

The LTH cases had a 4.3% incidence of emergency front of neck access (eFONA), which had an overall technique and attempt success rates of 100% and 66.7%, respectively. Two cases of failed eFONA were rescued by an alternative eFONA approach.^26,28 Most eFONA cases were associated with serious complications; for example, cyanosis,²⁶ severe hypoxia (SpO₂ 30%),²⁸ hypoxic brain damage, cardiac arrest and death.⁹

Oesophageal intubation occurred in 10 (10.9%) LTH cases.^2,9,20,23,51 Other complications included oropharyngeal bleeding in nine (9.8%) cases, severe hypoxia in three (3.3%) cases,^9,28,53 and one case (1.1%) each of an oesophageal tear,² epistaxis⁵¹ and death.⁹

Discussion

In our review of the literature reporting anaesthetic management of patients with LTH we found that LTH was usually not identified on clinical airway assessment, techniques to secure the airway had lower rates of success compared with other studies of difficult airways,^61,62 and failure to secure the airway often led to serious complications.

Routine airway assessment did not pick up lingual tonsillar hypertrophy

Most LTH cases had a ‘normal airway’ on assessment and only 13.5% of cases had OSA or LTH associated symptoms. This suggests that routine airway assessment rarely identifies LTH due to its tongue-base location, although in one case it was seen on oral examination.²⁵ The high PPV for difficult intubation in LTH cases reflects the high prevalence of difficult intubation.⁶³ Of concern, the low NPV values in LTH patients may lead clinicians erroneously to assume an easy intubation. In the case series of unanticipated failed intubation by Ovassapian et al., preoperative airway assessment by an experienced anaesthetist failed to suggest a difficult airway in almost half of the patients, when LTH was the only finding that could have contributed to failure of intubation.²

Most LTH cases were unanticipated difficult airways, for which the Difficult Airway Society (DAS) recommend a plan A, B, C, D strategy: plan A, face mask ventilation and laryngoscopy; B, supraglottic airway insertion and ventilation; C, final attempt at face mask ventilation; and D, emergency front of neck access (eFONA).¹³ Optimization manoeuvres are carried out while early priming of eFONA allows its implementation as soon as a ‘cannot intubate, cannot oxygenate’ (CICO) is declared.⁶⁴ In addition, the Vortex is a recently introduced tool that facilitates efficient implementation of best efforts at upper airway lifelines (facemask ventilation, supraglottic airway ventilation and laryngoscopy) with early and parallel preparation, priming and implementation of eFONA.

Awake tracheal intubation may be the best option for known severe lingual tonsillar hypertrophy patients

For LTH patients with an anticipated difficult airway, reports indicated preoperative airway assessment with flexible nasendoscopy and radiological investigations may be helpful.^1,6 A flexible nasendoscopy gives a ‘birds eye view’ of the oropharynx. A ‘negative’ flexible nasendoscopy view (i.e. glottis not visualised) may be due to abnormal anatomy (e.g reduced neck mobility) or the presence of an airway lesion (e.g. obstructing, vascular, friable or a rapidly changing one), and thus predict a difficult airway. However, photographs from Ovassapian et al. also show falsely reassuring ‘positive’ awake flexible nasendoscopy views (i.e. glottis seen), yet all were from patients who had failed intubation.² This may be partly explained by the flexible nasendoscopy being performed in the awake patient. However, after induction of anaesthesia, there is an abrupt decrease in upper airway muscle activity and increase in upper airway collapsibility.⁶⁵ This, with the added presence of LTH causing obstruction, may lead to difficult facemask ventilation and difficult intubation.

In the anticipated difficult airway, awake intubation techniques may be indicated.^66,67 In the LTH cases, awake preoperative and postoperative FBI had high success rates, that is, 100% and 88.9%, respectively, which may be explained as follows. Airway patency, airway protective reflexes and spontaneous ventilation are maintained. A sitting patient has added advantages—gravity helps open up the airway and secretions are pooled away and functional residual capacity is increased.⁶⁸ The absence of induction agents helps maintain cardiovascular stability. In the LTH cases, awake FBI views were improved when the LTH mass was displaced by changing a patient from supine to a sitting position,³⁷ or when the patient was asked to phonate ‘E’.³¹ However, awake FBI has been associated with airway obstruction or loss of airway control due to sedation and local anaesthetic topicalization.^60,66

The incidence of difficult and impossible facemask ventilation was higher in the LTH cases than that reported in the general population (29.6 vs. 1.4% and 1.4% vs. 0.16%, respectively).⁶⁹ Facemask ventilation may be more difficult as the LTH may distort the supraglottis,^{2,19,23,25,26,36,38,39} or overhang the borders of the epiglottis and cause airway obstruction.² Posterior displacement of the tongue may limit airflow from both nasal and oral routes, and an increased thickness of the tongue base is a predictor of difficult face mask ventilation.⁷⁰

Direct laryngoscopy commonly failed in lingual tonsillar hypertrophy cases

Difficult and failed intubation rates in the LTH cases compared unfavourably with those from the unselected population: 89.1% versus 0.3–13.3%¹² and 21.7% versus 0.4%,⁶¹ respectively. Direct laryngoscopy in our LTH cases had an overall technique success rate of 15.4%, which contrasts with 90.6% from a Cochrane review of adult patients (with or without predicted/known difficult airways) requiring tracheal intubation.⁷¹ There are various reasons to explain this. All our cases likely had clinically significant LTH whereas the incidence of LTH across surgical patients is low (0.3–3%).^3
–5 Direct laryngoscopy requires a ‘line of sight’ to the larynx,⁷² which is obtained by inserting the laryngoscope blade lateral to the tongue, moving the latter to the left, and then advancing the blade in the midline into the vallecula to visualise the glottis.⁷² However, this may not be possible if the LTH lesion occupies the entire vallecula,^1,7 or causes the epiglottis to be downfolded, retroflexed, immobile or buried.^{2,19,23,25,26,36,38,39} In addition, if the tongue is not displaced to the left, the base of the tongue may be compressed distally producing posterior displacement of the epiglottis.⁷²

Straight blade laryngoscopy has theoretical advantages over Macintosh laryngoscopy for LTH cases: reduced lifting, compression and displacement of the tongue and epiglottis; an improved line of sight (no intrusion as seen with the curved Macintosh blade); and with the retromolar approach, reduction of the intrusion of maxillary structures into the line of sight.⁷³ However, straight blade laryngoscopy in LTH cases still had a low success rate and this may be due to it being not commonly used or taught, the aryepiglottic fold may obscure the glottis with the paraglossal approach, and control of the epiglottis may be poorer.⁷³

Most LTH cases pre-dated the introduction of videolaryngoscopy in the early 2000s. However, there are various benefits of videolaryngoscopy over direct laryngoscopy:^71,74 improved glottic view, less airway trauma, reduced number of failed intubations, shorter learning curves, and a shared ‘video’ view of the airway. However, videolaryngoscopy in LTH cases resulted in a lower overall technique success rate (50%) than those seen in other studies (Tables 3 and 4).^61,75 Several factors may account for this. Our review only contained six cases. Correct videolaryngoscope placement may be impaired by the LTH or decreased oropharyngeal space as seen in obese and OSA patients.^76,77 Compression of the tongue, distortion of the epiglottis and bleeding during videolaryngoscopy were reported in several cases.^{16,20,23,39,44,58,59} LTH may also obstruct the videolaryngoscope light, creating a shadow and preventing glottic visualization.¹⁵ There may also be a ‘blind spot’ during videolaryngoscopy, that is, after the tracheal tube enters the oropharynx but before it comes into view on the device’s monitor, leading to airway trauma.⁴⁵

Multiple attempts at intubation were associated with an increased incidence of serious morbidity,⁷⁸ and the number of attempts should be limited.^66,78 Furthermore, in cases with a documented number of attempts, no successful intubations occurred after a third attempt using direct laryngoscopy. This is important as it suggests that further attempts may be futile or harmful, countering the DAS recommended maximum ‘3 + 1’ attempts, where the ‘+1’ refers to a ‘fourth attempt by a more experienced colleague’.¹³

Rescue supraglottic ventilation succeeded in only three-quarters of lingual tonsillar hypertrophy cases

After failed intubation, an attempt to rescue ventilation by a supraglottic airway is recommended^13,64,66 as it has a success rate of 65.1–94% in the literature.^62,79 In LTH cases, it provided easy/adequate and difficult ventilation in 72.0% and 20.0% of cases, respectively. However, in some LTH cases, insertion of a supraglottic airway failed or caused bleeding.^17,28 If supraglottic airway ventilation is successful, four options are available:¹³ proceed with surgery with the supraglottic airway in situ, perform SGI, wake up the patient, or perform eFONA. The first option is a high-risk strategy in LTH cases as a CICO scenario may result from airway oedema, bleeding, laryngospasm, and supraglottic airway displacement.^13,66 This option was chosen in one LTH case for urgent surgery,⁶⁴ but we would recommend that eFONA be primed and ready to implement.

FBI under anaesthesia had a lower success rate than for awake FBI (Table 4) and may be due to several reasons. All the advantages of an awake intubation are lost (see above). Many cases were obese and some developed severe hypoxia leading to stress and time pressure on the anaesthetist. Impingement during railroading of the tracheal tube over the bronchoscope may be caused by LTH mass, distorted laryngeal structures, and decreased airway patency secondary to anaesthesia, OSA and obesity. SGI overall technique success rate was 46.2% (Table 4) which is lower than from other studies, that is, 54–94%,^61,66 and may be due to the LTH impairing the bronchoscope reaching, or visualising, the glottis.

When a CICO scenario is anticipated, early transition, priming and implementation of eFONA is warranted to avoid hypoxic brain injury and death.^{9,13,64,66,80} The LTH cases had a 4.3% incidence of eFONA which is one to two orders of magnitude higher than in adults presenting for surgery (0.01%) or ear, nose and throat procedures (0.2%).⁸¹ The overall technique and attempt success rates were 100% and 66.7%, respectively. Two cases of failed eFONA were rescued by an alternative eFONA approach.^26,28 Most eFONA cases were associated with serious complications,^9,26,28 and may suggest the need for improved training in, and early priming and implementation of, the technique.^64,80

Waking up the patient was attempted in 16.5% of cases, which compares with 0.8% of patients in a study of failed laryngoscopy.⁶¹ However, it may not be possible or safe to wake up a patient due to airway oedema or bleeding, cardiac or respiratory instability, urgency of surgery, or inability to reverse the effects of anaesthetic or neuromuscular blocking agents in a timely manner. In one case, after waking up the patient following multiple failed airway techniques, the patient struggled to breathe, became cyanotic and required eFONA.²⁶

There were many airway-related complications described in the LTH cases, with hypoxic brain damage and death being the most serious.⁹ To minimise future complications, Ovassapian et al. recommended fibreoptic nasendoscopy in all patients with unanticipated failed intubation to rule out LTH.² Identifiable risk factors for airway complications in the LTH cases included poor management,⁶⁶ obesity,⁸⁰ emergency out-of-hours surgery, multiple attempts at tracheal intubation,^78,80 and performing eFONA. A fifth of cases had a BMI of 40 kg/m² or greater (‘morbid obesity’) and airway management is more difficult in such patients due to the shorter safe apnoea time and higher incidence of difficult airways.^66,82 Oesophageal intubation in LTH cases was not uncommon, and its incidence is higher than in other studies (10.9% vs. 1–2%, respectively).⁸⁰ Other non-LTH factors may also have contributed to difficulties in airway management: acromegaly,^20,37 temporomandibular joint ankylosis,³⁵ LTH bleeding precluding the use of FBI,²³ epistaxis,^51,59 patient refusal for awake tracheal intubation,²⁹ and the nasal route not being available for FBI due to the site of surgery.²⁰

The airway management of some of the LTH cases may be open to criticism, for example, multiple attempts at airway techniques, blind attempts at intubation (in one case causing bleeding),¹⁵ and not performing awake tracheal intubation despite seeing ‘enormous’ LTH on oral examination.²⁵ Four cases had known LTH but awake tracheal intubation was not performed.^25,45,52,57 At the risk of hindsight bias, this raises the question whether awake FBI would have avoided subsequent airway complications such as palatal perforation⁴⁵ or the need for tracheostomy.²⁵

This review is limited by being drawn from mainly case reports and a major case series, constituting a lower level of evidence. In a previous small case series, the authors found no association between LTH and difficult airways.⁵ However, it consisted of six cases screened from patients scheduled for elective surgery, and there was no grading of the severity of the LTH. In the current review, data were combined for statistical analysis so caution should be used when interpreting the results. Our comments and recommendations apply only to cases with clinically significant LTH as most of the cases were likely to be grade 4. None of the cases were formally graded as the Friedmann classification is a recent addition.⁷ Also, success of airway techniques cannot be accurately calculated as the cases are heterogeneous. Further, data were lacking in many cases, for example, BMI, OSA, previous tonsillectomy, detailed airway assessment, number of attempts of each airway intervention, and the frequency and severity of complications. Although CL grade 3 is included in the definition of ‘difficult intubation’, intubation may still be straightforward with the aid of intubating adjuncts such as a bougie. Reporting and publication bias also favour severe cases and cases when novel airway techniques are used. Despite these limitations, this review provides a detailed database for LTH management.

It should be noted that a third of the reports in this review were published over 20 years ago and so would not have benefitted from recent advances in anaesthetic airway management. These include videolaryngoscopy and second generation supraglottic airways,⁸⁰ sugammadex for rapid reversal of neuromuscular blockade, difficult airway algorithms,^13,64,67 lessons learnt from large national airway audits (e.g. NAP4),⁶⁶ high flow nasal oxygen to prolong safe apnoea time, and availability of difficult airway databases to identify at-risk patients.⁸⁰

Conclusions

The findings of this review indicate that LTH is rarely identified on routine airway assessment. Severe cases may lead to unanticipated difficult airways and associated morbidity and even mortality. Rescue techniques after failed intubation may fail due to their exacerbation of the space occupying effect of LTH. A robust airway strategy for managing patients with severe LTH includes consideration of awake tracheal intubation, which has a high success rate. The efficient use of upper airway resources is required including limiting the number of laryngoscopic attempts (more than three attempts at direct laryngoscopy may be futile and harmful), considering the use of straight blade laryngoscopy if experienced, and being mindful that rescue supraglottic airway ventilation may be difficult or fail in up to 30% of severe LTH cases. Finally, plan for success but ‘prepare for failure’ which may require early priming and implementation of eFONA.

Footnotes

Author Contribution(s)

Patrick Wong: Conceptualization; Formal analysis; Methodology; Writing – original draft; Writing – review & editing.

Jamie W Sleigh: Conceptualization; Methodology; Writing – review & editing.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Patrick Wong

References

Golding-Wood

Whittet

HB.

The lingual tonsil. A neglected symptomatic structure?

J Laryngol Otol 1989; 103: 922–925. doi:10.1017/s0022215100110515

Ovassapian

Glassenberg

Randel

, et al. The unexpected difficult airway and lingual tonsil hyperplasia: a case series and a review of the literature. Anesthesiology 2002; 97: 124–132. doi:10.1097/00000542-200207000-00018

Asai

Liu

Matsumoto

, et al. Use of the Pentax-AWS in 293 patients with difficult airways. Anesthesiology 2009; 110: 898–904. doi:10.1097/ALN.0b013e31819c45e5

Adachi

Satomoto

Higuchi

, et al. Assessment of the lingual tonsil and vallecula during fiberoptic intubation. J Anesth 2002; 16: 345–348. doi:10.1007/s005400200054

Sánchez-Morillo

Gómez-Diago

Rodríguez-Gimillo

, et al. Airway evaluation by indirect laryngoscopy in patients with lingual tonsillar hypertrophy. Acta Otorrinolaringol Esp 2013; 64: 345–351. doi:10.1016/j.otorri.2013.04.004

Tang

Friedman

Incidence of lingual tonsil hypertrophy in adults with and without obstructive sleep apnea. Otolaryngol Head Neck Surg 2018; 158: 391–394. doi:10.1177/0194599817740333

Friedman

Salapatas

Bonzelaar

LB.

Updated Friedman staging system for obstructive sleep apnea. Adv Otorhinolaryngol 2017; 80: 41–48. doi:10.1159/000470859

Harris

Rotenberg

Roth

, et al. Factors associated with lingual tonsil hypertrophy in Canadian adults. J Otolaryngol Head Neck Surg 2017; 46: 32. doi:10.1186/s40463-017-0209-z

Jones

Cohle

SD.

Unanticipated difficult airway secondary to lingual tonsillar hyperplasia. Anesth Analg 1993; 77: 1285–1288. doi:10.1213/00000539-199312000-00033

10.

Samsoon

Young

JR.

Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42: 487–490. doi:10.1111/j.1365-2044.1987.tb04039.x

11.

Baker

Depuydt

Thompson

JMD.

Thyromental distance measurement—fingers don’t rule. Anaesthesia 2009; 64: 878–882. doi:10.1111/j.1365-2044.2009.05985.x

12.

Cook

TM.

A new practical classification of laryngeal view. Anaesthesia 2000; 55: 274–279. doi:10.1046/j.1365-2044.2000.01270.x

13.

Frerk

Mitchell

McNarry

, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015; 115: 827–848. doi:10.1093/bja/aev371

14.

Glen

Clopper–Pearson Exact Method. StatisticsHowTo.com: Elementary Statistics for the rest of us!, https://www.statisticshowto.com/clopper-pearson-exact-method/ (accessed 21 June 2023).

15.

Agnoletti

Piraccini

Corso

, et al. Failure of double-lumen tube positioning in a patient with lingual tonsil hypertrophy. J Cardiothorac Vasc Anesth 2011; 25: e20–e21. doi:10.1053/j.jvca.2011.01.002

16.

Al-Shamaa

Jefferson

Ball

DR.

Lingual tonsil hypertrophy: airway management. Anaesthesia 2003; 58: 1134–1135. doi:10.1046/j.1365-2044.2003.03499.x

17.

Andrews

Mabey

MF.

Tubular fiberoptic laryngoscope (WuScope) and lingual tonsil airway obstruction. Anesthesiology 2000; 93: 904–905. doi:10.1097/00000542-200009000-00052

18.

Arndt

Topp

Hannah

, et al. Intubation via the LMA using a Cook retrograde intubation kit. Can J Anaesth 1998; 45: 257–260. doi:10.1007/BF03012912

19.

Asai

Hirose

Shingu

Failed tracheal intubation using a laryngoscope and intubating laryngeal mask. Can J Anaesth 2000; 47: 325–328. doi:10.1007/BF03020946

20.

Asbjørnsen

Kuwelker

Søfteland

A case of unexpected difficult airway due to lingual tonsil hypertrophy. Acta Anaesthesiol Scand 2008; 52: 310–312. doi:10.1111/j.1399-6576.2007.01485.x

21.

Biro

Shahinian

Management of difficult intubation caused by lingual tonsillar hyperplasia. Anesth Analg 1994; 79: 389. doi:10.1213/00000539-199408000-00035

22.

Brimacombe

Keller

Gum elastic bougie-guided insertion of the LMA-ProSeal in occult tonsillar hypertrophy. Can J Anesth 2004; 51: 859. doi:10.1007/BF03018475

23.

Conacher

McMahon

Meikle

‘Chicane-like’ airway as a complication of lingual tonsils. Lancet 1996; 348: 475. doi:10.1016/s0140-6736(05)64568-0

24.

Crosby

Skene

More on lingual tonsillar hypertrophy. Can J Anaesth 2002; 49: 758. doi:10.1007/BF03017463

25.

Čukić

Nikolić

Jovanović

MB.

Massive benign lingual tonsil hyperplasia and tracheostomy. Mater Medica 2017; 33: 1568–1570. doi:10.5937/MatMed1703568C

26.

Davies

Ananthanarayan

Castro

Asymptomatic lingual tonsillar hypertrophy and difficult airway management: a report of three cases. Can J Anaesth 2001; 48: 1020–1024. doi:10.1007/BF030165

27.

Dell

RG.

Upper airway obstruction secondary to a lingual tonsil. Anaesthesia 2000; 55: 393. doi:10.1046/j.1365-2044.2000.01378-4.x

28.

Fundingsland

Benumof

JL.

Difficulty using a laryngeal mask airway in a patient with lingual tonsil hyperplasia. Anesthesiology 1996; 84: 1265–1266. doi:10.1097/00000542-199605000-00040

29.

Goldman

Rosenblatt

WH.

Use of the fibreoptic intubating LMA-CTrach in two patients with difficult airways. Anaesthesia 2006; 61: 601–603. doi:10.1111/j.1365-2044.2006.04660.x

30.

Greenland

Cumpston

PHV

Huang

Magnetic resonance scanning of the upper airway following difficult intubation reveals an unexpected lingual tonsil. Anaesth Intensive Care 2009; 37: 301–304. doi:10.1177/0310057X0903700216

31.

Henderson

Abernathy

Bays

Lingual tonsillar hypertrophy: the anesthesiologist’s view. Anesth Analg 1994; 79: 814–815. doi:10.1213/00000539-199410000-00049

32.

Higueras

Onrubia

Sánchez de Merás

, et al. Parker Flex-Tip tube for fibreoptic nasotracheal intubation in a case of lingual tonsil hypertrophy. Can J Anaesth 2005; 52: 778–779. doi:10.1007/BF03016578

33.

Kim

Hong

, et al. Difficult intubation due to unexpected lingual tonsil hyperplasia—case report. SAS J Med 2016; 2; 118–120.

34.

Kumar

Verma

Agarwal

Lingual tonsillar hypertrophy: cause of unanticipated difficult intubation. J Anaesthesiol Clin Pharmacol 2014; 30: 590–591. doi:10.4103/0970-9185.142907

35.

Kwon

Song

Park

Difficult airway management in a case with lingual tonsil hypertrophy and temporo-mandibular joint partial ankylosis. Korean J Anesthesiol 2013; 65: 359–360. doi:10.4097/kjae.2013.65.4.359

36.

Marcotegui-Barber

Bilbao-Ares

Lingual tonsillar hypertrophy, an unknown enemy: a case report. Colomb J Anesthesiol 2019; 47: 245–248. doi:10.1097/CJ9.0000000000000108

37.

Matioc

Olson

Use of the Laryngeal Tube in two unexpected difficult airway situations: lingual tonsillar hyperplasia and morbid obesity. Can J Anaesth 2004; 51: 1018–1021. doi:10.1007/BF03018491

38.

Ojeda

López

Borrat

, et al. Failed tracheal intubation with the LMA-CTrach in two patients with lingual tonsil hyperplasia. Anesth Analg 2008; 107: 601. doi:10.1213/ane.0b013e318176fb0b

39.

Orhan

Gözübüyük

Sızlan

, et al. Unexpected difficult intubation due to lingual tonsillar hyperplasia in a thoracotomy patient: intubation with the double-lumen tube using stylet and fiberoptic bronchoscopy. J Clin Anesth 2009; 21: 439–441. doi:10.1016/j.jclinane.2008.10.016

40.

Patel

Davidian

Reebye

Complicated airway due to unexpected lingual tonsil hypertrophy. Anesth Prog 2012; 59: 82–84. doi:10.2344/11-06.1

41.

Ralph

Jr Huh

Kim

Phenytoin-induced lingual tonsil hyperplasia causing laryngeal obstruction. Ann Otol Rhinol Laryngol 2001; 110: 790–793. doi:10.1177/000348940111000817

42.

Rosenblatt

WH.

The use of the LMA-ProSeal in airway resuscitation. Anesth Analg 2003; 97: 1773–1775. doi:10.1213/01.ANE.0000085300.41506.EF

43.

Schroeder

Becker

Guite

, et al. Severe lingual tonsillar hypertrophy and the rationale supporting early use of wire-guided retrograde intubation. Saudi J Anaesth 2010; 4: 102–104. doi:10.4103/1658-354X.65120

44.

Souki

Yemul-Golhar

Zeyed

, et al. Lingual tonsil hypertrophy: rescuing the airway with videolaryngoscopy. J Clin Anesth 2016; 35: 242–245. doi:10.1016/j.jclinane.2016.06.007

45.

Williams

Ball

DR.

Palatal perforation associated with McGrath videolaryngoscope. Anaesthesia 2009; 64: 1144–1145. doi:10.1111/j.1365-2044.2009.06091.x

46.

Adachi

Uchihashi

Sugahara

, et al. [Successful fiberoptic intubation for a patient with lingual tonsillar hyperplasia.] Masui 2000; 49: 768–770.

47.

Enya

Yoshiyama

Chuma

Retrograde endotracheal intubation with laryngeal mask airway in a patient with lingual tonsillar hypertrophy. J Jpn Soc Clin Anesth 1995; 15: 703–705. doi:10.2199/jjsca.15.703

48.

Kamada

Kouno

Satake

, et al. Use of intubating laryngeal mask airway in combination with fiberoptic intubation in a patient with morbid obesity and unexpected lingual tonsillar hypertrophy. Masui 2010; 59: 460–463.

49.

Kamiya

Satomoto

Tokunaga

, et al. Intubation in a patient with lingual tonsil hypertrophy using an intubating laryngeal mask airway in combination with fiberoptic intubation. Masui 2002; 51: 523–525.

50.

Komasawa

Manabe

Ueki

, et al. Efficacy of bronchofiberscope combined with Pentax-AWS Airwayscope in patients with unanticipated difficult airway with lingual tonsil hyperplasia. J Jpn Soc Clin Anesth 2011; 31: 182–186. doi:10.2199/jjsca.31.182

51.

Kuroiwa

Mochizuki

Sato

A case of an unexpected difficult nasal intubation, caused by hypertrophied lingual tonsil. Masui 2013; 62: 172–174.

52.

Myojo

Tohyama

Taki

, et al. [Tracheal intubation for two patients with lingual tonsil hyperplasia and prospect of difficult airway management.] Masui 2005; 54: 776–782.

53.

Obata

Adachi

Igarashi

, et al. Difficult airway management due to obesity and lingual tonsillar hyperplasia. Masui 2008; 57: 1269–1272.

54.

Terada

Nakamura

Fukuyama

, et al. A case of difficult airway caused by lingual tonsil hyperplasia and epiglottic cyst. J Jpn Soc Clin Anesth 2003; 23: 149–152. doi:10.2199/jjsca.23.149

55.

ruz

Alarcón

Del Castillo

, et al. Effectiveness of the GlideScope video laryngoscope in a case of unexpected difficult airway due to lingual tonsil hypertrophy. Rev Esp Anestesiol Reanim 2015; 62: 289–292. doi:10.1016/j.redar.2014.09.011

56.

Saturno Marcos

Escribano Jiménez

Rodríguez-Navarro

, et al. [Unanticipated difficult airway: lingual tonsil hypertrophy.] Rev Esp Anestesiol Reanim 2009; 56: 574–575. doi:10.1016/s0034-9356(09)70463-3

57.

Bae

JH.

Difficult tracheal intubation due to lingual tonsillar hypertrophy: a case report. Korean J Anesthesiol 2005; 49: 698–701. doi:10.4097/kjae.2005.49.5.698

58.

Clavier

Compère

Hibon

, et al. [Lingual tonsil hypertrophy and unanticipated difficult airway management.] Ann Fr Anesth Reanim 2011; 30: 375–376. doi:10.1016/j.annfar.2011.01.005

59.

Salvi

Juliano

Zucchetti

, et al. Hypertrophy of the lingual tonsil and difficulty in airway control. A clinical case. Minerva Anestesiol 1999; 65: 549–553.

60.

Lee

JSE

Wong

Iqbal

, et al. Practical aspects and training in fibreoptic intubation. Trends Anaesth Crit Care 2016; 10: 29–41. doi:10.1016/j.tacc.2016.08.002

61.

Aziz

Brambrink

Healy

, et al. Success of intubation rescue techniques after failed direct laryngoscopy in adults: a retrospective comparative analysis from the Multicenter Perioperative Outcomes Group. Anesthesiology 2016; 125: 656–666. doi:10.1097/ALN.0000000000001267

62.

Parmet

Colonna-Romano

Horrow

, et al. The laryngeal mask airway reliably provides rescue ventilation in cases of unanticipated difficult tracheal intubation along with difficult mask ventilation. Anesth Analg 1998; 87: 661–665. doi:10.1097/00000539-199809000-00032

63.

Trevethan

Sensitivity, specificity, and predictive values: foundations, pliabilities, and pitfalls in research and practice. Front Public Health 2017; 5: 307. doi:10.3389/fpubh.2017.00307

64.

Chrimes

The Vortex: a universal ‘high-acuity implementation tool’ for emergency airway management. Br J Anaesth 2016; 117(Suppl. 1): i20–i27. doi:10.1093/bja/aew175

65.

Hillman

Walsh

Maddison

, et al. Evolution of changes in upper airway collapsibility during slow induction of anesthesia with propofol. Anesthesiology 2009; 111: 63–71. doi:10.1097/ALN.0b013e3181a7ec68

66.

Cook

Woodall

Frerk

(eds) The NAP4 report: Major complications of airway management in the UK. Royal College of Anaesthetists. London. https://www.nationalauditprojects.org.uk/downloads/NAP4%20Full%20Report.pdf (2011).

67.

Apfelbaum

Hagberg

Connis

, et al. 2022 American Society of Anesthesiologists practice guidelines for management of the difficult airway. Anesthesiology 2021; 136: 384–400. doi:10.1097/ALN.0000000000004002

68.

Wahba

RW.

Perioperative functional residual capacity. Can J Anaesth 1991; 38: 384–400. doi:10.1007/BF03007630

69.

Kheterpal

Han

Tremper

, et al. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology 2006; 105: 885–891. doi:10.1097/00000542-200611000-00007

70.

Bianchini

Nardozi

Nardi

, et al. Airways ultrasound in predicting difficult face mask ventilation. Minerva Anestesiol 2021; 87: 26–34. doi:10.23736/S0375-9393.20.14455-9

71.

Lewis

Butler

Parker

, et al. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database Syst Rev 2016; 11: CD011136. doi:10.1002/14651858.CD011136.pub2

72.

Henderson

JJ.

Questions about the macintosh laryngoscope and technique of laryngoscopy. Eur J Anaesthesiol 2000; 17: 2–5. http://dx.doi.org/10.1046/j.1365-2346.2000.00611.x

73.

Henderson

JJ.

The use of paraglossal straight blade laryngoscopy in difficult tracheal intubation. Anaesthesia 1997; 52: 552–560. doi:10.1111/j.1365-2222.1997.129-az0125.x

74.

Kelly

Cook

TM.

Seeing is believing: getting the best out of videolaryngoscopy. Br J Anaesth 2016; 117(Suppl. 1): i9–i13. doi:10.1093/bja/aew052

75.

Kleine-Brueggeney

Greif

Schoettker

, et al. Evaluation of six videolaryngoscopes in 720 patients with a simulated difficult airway: a multicentre randomized controlled trial. Br J Anaesth 2016; 116: 670–679. doi:10.1093/bja/aew058

76.

Neelapu

Kharbanda

Sardana

, et al. Craniofacial and upper airway morphology in adult obstructive sleep apnea patients: a systematic review and meta-analysis of cephalometric studies. Sleep Med Rev 2017; 31: 79–90. doi:10.1016/j.smrv.2016.01.007

77.

Fujimoto

Urushibata

, et al. Cephalometric analysis in obese and nonobese patients with obstructive sleep apnea syndrome. Chest 2003; 124: 212–218. doi:10.1378/chest.124.1.212

78.

Mort

TC.

Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg 2004; 99: 607–613. doi:10.1213/01.ANE.0000122825.04923.15

79.

Thomsen

JLD

Nørskov

Rosenstock

CV.

Supraglottic airway devices in difficult airway management: a retrospective cohort study of 658,104 general anaesthetics registered in the Danish Anaesthesia Database. Anaesthesia 2019; 74: 151–157. doi:10.1111/anae.14443

80.

Cook

TM.

Strategies for the prevention of airway complications—a narrative review. Anaesthesia 2018; 73: 93–111. doi:10.1111/anae.14123

81.

Rosenstock

Nørskov

Wetterslev

, et al. Emergency surgical airway management in Denmark: a cohort study of 452 461 patients registered in the Danish Anaesthesia Database. Br J Anaesth 2016; 117(Suppl. 1): i75–i82. doi:10.1093/bja/aew190

82.

Members of the Working Party, Nightingale

Margarson

, et al. Peri-operative management of the obese surgical patient 2015: Association of Anaesthetists of Great Britain and Ireland Society for Obesity and Bariatric Anaesthesia. Anaesthesia 2015; 70: 859–876. doi:10.1111/anae.13101

Airway management of lingual tonsillar hypertrophy: A narrative review

Abstract

Keywords

Introduction

Methods

Statistical analysis

Results

Discussion

Routine airway assessment did not pick up lingual tonsillar hypertrophy

Awake tracheal intubation may be the best option for known severe lingual tonsillar hypertrophy patients

Direct laryngoscopy commonly failed in lingual tonsillar hypertrophy cases

Rescue supraglottic ventilation succeeded in only three-quarters of lingual tonsillar hypertrophy cases

Conclusions

Footnotes

Author Contribution(s)

Declaration of conflicting interests

Funding

ORCID iD

References