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Mediastinal goiter and tracheal deviation at CXR: Asterisks: Mediastinal goiter shadow, arrow: Tracheal deviation.
Source publication
Introduction
Difficult tracheal intubation (DTI) contributes to perioperative morbidity and mortality. There are conflicting study results about the most predictive DTI risk criteria in patients undergoing thyroid surgery.
Materials and methods
We conducted a prospective observational study on 500 consecutive patients aged ≥18 years to identify p...
Citations
... For example, while conducting general anesthesia in patients undergoing a thyroidectomy, difficult tracheal intubation might occur due to the mass effect of the goiter or tumor. The overall incidence of difficult intubation in a thyroidectomy varied, e.g., 5.3% [14], 5.5% [15], 7% [16], 8.5% [17], 9.6% [18], and 11.1% [19]. ...
The purpose of this case series report is to demonstrate the current state of the art regarding tracheal intubation of an evoked electromyography-endotracheal tube (EMG-ET tube) for continuous intraoperative recurrent laryngeal nerve monitoring (IONM) in patients undergoing thyroid surgery. Both direct laryngoscopy (DL) and videolaryngoscopy (VL) are popular for routine tracheal intubation of an EMG-ET tube. A new intubating technique (styletubation), using a video-assisted intubating stylet (VS), provides less traumatic and swift intubation. Styletubation combined with VL ensures the precise placement of the EMG-ET tube. This novel intubation technique improves the outcome of intubating an EMG-ET tube for IONM.
... Zheng et al. report a single center experience of 12.7% of difficult intubations in 472 patients scheduled for oral cavity and oropharyngeal cancer surgery 29 . In a prospective observational study on 500 consecutive thyroid patients, it was observed in 9.6% of thyroid surgery patients 30 . The incidence of difficult intubation in thyroid surgery patients may be lower in patients with the Trachway procedure (2.7%) than in direct laryngoscopy (6.5%, p=0.01) 31 . ...
The aim of this study was to assess preoperative airway history data and single anthropometric screening tests of difficult face mask ventilation (FMV) and difficult direct laryngoscopy intubation (DLI) in otorhinolaryngological surgery. Final analysis included 62 patients aged ≥14 years undergoing elective surgery with endotracheal intubation at a single center during a one-month period. Data on difficult intubation history, airway symptoms and pathology related to difficult airway were prospectively collected. Han scoring classification of FMV and Intubation Difficulty Score (IDS) were used. There were 14 (22.6%) patients with a history of current airway tumors or abscesses. Only two (3.2%) patients were preoperatively evaluated as anticipated difficult airway. Both were slightly difficult to ventilate and scored IDS 5 and IDS 8. FMV was graded as easy in 50 (80.5%), slightly difficult in 10 (16.1%) and difficult in 2 (3.2%) cases. There were 29 (46.78%) slightly difficult DLIs and one (1.6%) case of difficult DLI. The study confirmed clinically relevant incidence of difficulties with FMV and DLI in otorhinolaryngologic surgery patients. However, there should be stronger evidence to identify a single preoperative variable predicting difficult airway.
... Regarding the multifactorial nature of DL, none of the preoperative tests was solely reported to have conformably high sensitivity and specificity rates [2,3,11] . Moreover, cutoff values and diagnostic accuracy of these tests vary with respect to several confounding factors like BMI, gender, and ethnicity [14,16,20,23] . Hence, iterative validation of these tests and their combinations in different patient groups is essential to confirm their predictivity. ...
... NC was determined as a valuable indicator of DL particularly for obese patients and in the thyroid surgery [12,21,23] . According to Özdilek et al., NC was not a significant predictor neither for DVL nor for difficult mask ventilation [17] . ...
... We are grateful to the BioStudies database for providing the original data (28). ...
Background
In this paper, we examine whether machine learning and deep learning can be used to predict difficult airway intubation in patients undergoing thyroid surgery.
Methods
We used 10 machine learning and deep learning algorithms to establish a corresponding model through a training group, and then verify the results in a test group. We used R for the statistical analysis and constructed the machine learning prediction model in Python.
Results
The top 5 weighting factors for difficult airways identified by the average algorithm in machine learning were age, sex, weight, height, and BMI. In the training group, the AUC values and accuracy and the Gradient Boosting precision were 0.932, 0.929, and 100%, respectively. As for the modeled effects of predicting difficult airways in test groups, among the models constructed by the 10 algorithms, the three algorithms with the highest AUC values were Gradient Boosting, CNN, and LGBM, with values of 0.848, 0.836, and 0.812, respectively; In addition, among the algorithms, Gradient Boosting had the highest accuracy with a value of 0.913; Additionally, among the algorithms, the Gradient Boosting algorithm had the highest precision with a value of 100%.
Conclusion
According to our results, Gradient Boosting performed best overall, with an AUC >0.8, an accuracy >90%, and a precision of 100%. Besides, the top 5 weighting factors identified by the average algorithm in machine learning for difficult airways were age, sex, weight, height, and BMI.
... Various predictors have been developed to assess difficult intubation. Current predictors include the Mallampati score, thyromental distance (TM), Wilson Score, width of mouth opening etc. 5 but none of them has a significant diagnostic accuracy in clinical anaesthetic practice. All tests have their limitations, especially in obese patients. ...
Objective: To ascertain the diagnostic accuracy of raised neck circumference to thyromental distance ratio (NC/TMD) for difficulty in intubation among patients with obesity keeping grades III and IV of Cormack and Lehane's score as the gold standard. Study Design: Cross-sectional validation study. Place and Duration of Study: Anesthesiology Department, Combined Military Hospital Rawalpindi, from Jul to Dec 2017. Methodology: One hundred and thirty obese patients who had to undergo surgery under general anaesthesia were included in the study. All the patients underwent measurement of neck circumference to thyromental distance ratio, and raised neck circumference to thyromental distance ratio was noted. Difficult intubation was labelled according to the grades III and IV of Cormack and Lehane's score. Results: In this study, 130 cases were included. Fifty-eight patients were males, and 72 were females. Diagnostic accuracy of raised neck circumference to thyromental distance ratio for difficulty in intubation among patients who were obese, was recorded where sensitivity was 83.87%, and specificity was found to be 91.92%, positive predictive value as 76.47%, negative predictive value as 94.79%, the accuracy rate was calculated as 90%. Conclusion: Our study showed that difficulty in intubation is more frequent in patients who are obese and the neck circumference to thyromental distance ratio is a reliable method for foreseeing difficult intubation compared to other established predictors with cut off value of 5.0.
... A history of previous difficulty is more often correctly predictive of difficulty than the bedside examination. [11][12][13][14][15] Alone or in combination, the various bedside screening tests of anatomic features have been criticized for their poor performance in correctly predicting when difficulty will indeed occur with airway management. 11,13,16 Nevertheless, the presence of certain anatomic features (Tables 1, 2, 3 , 4, 5, 6, 7) should alert the airway manager to carefully consider the safest approach to airway management and which devices to have available; little downside will accrue if airway management turns out to be non-problematic. ...
... 2 A higher BMI is associated with difficult FMV. 25,28,40,[45][46][47][48] A co-existing thick neck [40][41][42] (e.g., circumference [ 40-50 cm), obstructive sleep apnea (OSA), 25,40,43,46,167 and/or a history of snoring 39,45,47,48 are also associated with difficult FMV. A thick neck 15,28,[190][191][192] and OSA 167 are associated with difficult Table 10 continued ...
... Recommendations for the anticipated difficult airway DL or intubation. Whether obesity alone predicts difficult laryngoscopy/intubation continues to be controversial, with some studies reporting an association, 15,29,31,39,[192][193][194][195] and others not. 11,25,191,[196][197][198] No studies have yet reported obesity to be a risk factor for difficult or failed VLfacilitated tracheal intubation, although one study has reported a thick neck to be associated with failed HA-VLfacilitated tracheal intubation. ...
Purpose:
Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the published airway management literature has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This second of two articles addresses airway evaluation, decision-making, and safe implementation of an airway management strategy when difficulty is anticipated.
Source:
Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence is lacking, statements are based on group consensus.
Findings and key recommendations:
Prior to airway management, a documented strategy should be formulated for every patient, based on airway evaluation. Bedside examination should seek predictors of difficulty with face-mask ventilation (FMV), tracheal intubation using video- or direct laryngoscopy (VL or DL), supraglottic airway use, as well as emergency front of neck airway access. Patient physiology and contextual issues should also be assessed. Predicted difficulty should prompt careful decision-making on how most safely to proceed with airway management. Awake tracheal intubation may provide an extra margin of safety when impossible VL or DL is predicted, when difficulty is predicted with more than one mode of airway management (e.g., tracheal intubation and FMV), or when predicted difficulty coincides with significant physiologic or contextual issues. If managing the patient after the induction of general anesthesia despite predicted difficulty, team briefing should include triggers for moving from one technique to the next, expert assistance should be sourced, and required equipment should be present. Unanticipated difficulty with airway management can always occur, so the airway manager should have a strategy for difficulty occurring in every patient, and the institution must make difficult airway equipment readily available. Tracheal extubation of the at-risk patient must also be carefully planned, including assessment of the patient's tolerance for withdrawal of airway support and whether re-intubation might be difficult.
... 37 in patients undergoing thyroid surgery, the incidence of difficult airways ranges from 6.8% to 9.6%. 38,39 De cassai et al. carried out a meta-analysis on the parameters predictive of difficult airways in this type of surgery, published in March. 40 they found that tracheal deviation added to traditional parameters like high Mallampati score, shorter thyromental distance, inter incisor gap, and obesity to increase predictivity. ...
... Numerous preoperative tests are continuously being proposed and assessed in order to predict difficult laryngoscopy, particularly in especially challenging settings, such as thyroid surgery (15). Sternomental distance has been proposed as a good predictor for difficult laryngoscopy, but various cut-off points have been proposed without being sufficiently accurate (16). ...
Objective:
The aim of the present preliminary study was to assess whether the sternomental distance ratio (SMDR) could be suitable as a predictor of difficult laryngoscopy, in both normal surgical patients and patients scheduled to undergo thyroid tumor surgery.
Methods:
Two hundred and twenty-one consecutive adult patients (among them 122 patients with presumed normal airways and 33 patients with thyroid tumors), scheduled to undergo elective surgery under general anesthesia, were included in this study. Physical and airway characteristics, SMDR, difficult laryngoscopy (using Cormack-Lehane scale) and any kind of assisted intubation were assessed.
Results:
Decreased SMDR demonstrated a strong correlation with difficult laryngoscopy in both thyroid tumor (Kendall's tau-b -0.578 (P=0.004) and normal patients -0.362 (P<0.001). Difficult laryngoscopy was 0 at SMDR>1.9 and 33% at SMDR <1.55 (P<0.001). The higher the SMDR was, the better the glottic view obtained.
Conclusions:
? SMDR>1.9 indicates an easy laryngoscopy, whereas SMDR <1.55 indicates a difficult one in both thyroid tumor and normal patients. SMDR is an objective test to assess difficult airway in thyroid surgery.
... Hui et al. [18] suggests that sublingual ultrasound can serve as a potential tool for predicting a difficult airway as a complementary measure to classical prediction methods. Along these lines, some studies suggest that the volume and thickness of the tongue can predict a difficult airway [19,20], whereas other studies have implicated the neck circumference as a major predictor [21,22]. More related to the current work, some studies have measured the anterior soft tissue thickness via ultrasound for predicting a difficult laryngoscopy [8,23,24], but these studies have yet not established a standard for which method is best. ...
Background:
Abnormal laryngeal structures are likely to be associated with a difficult laryngoscopy procedure. Currently, laryngeal structures can be measured by ultrasonography, however, little research has been performed on the potential role of ultrasound on the evaluation of a difficult laryngoscopy. The present study investigated the value of laryngeal structure measurements for predicting a difficult laryngoscopy.
Objective:
The main objective of this study was to explore the value of laryngeal structure measurements for predicting a difficult laryngoscopy.
Methods:
Two hundred and eleven adult patients (over 18 years old) were recruited to undergo elective surgery under general anesthesia via endotracheal intubation. Ultrasound was utilized to measure the distance between the skin and thyroid cartilage (DST), the distance between the thyroid cartilage and epiglottis (DTE), and the distance between the skin and epiglottis (DSE) in the parasagittal plane. These metrics were then investigated as predictors for classifying a laryngoscopy as difficult vs easy, as defined by the Cormack and Lehane grading scale.
Results:
Multivariate logistic regression showed that the DSE, but not DST or DTE, was significantly related to difficult laryngoscopies. Specifically, a DSE ≥ 2.36 cm predicted difficult laryngoscopies with a sensitivity and specificity of 0.818 (95% CI: 0.766-0.870) and 0.856 (95% CI: 0.809-0.904). Furthermore, when combining the best model constructed of other indicators (i.e. sex, body mass index, modified Mallampati test) to predict the difficult laryngoscopy, the AUC reached 93.28%.
Conclusion:
DSE is an independent predictor of a difficult laryngoscopy; a DSE cutoff value of 2.36 cm is a better predictor of a difficult laryngoscope than other ultrasound or physiological measurements for predicting a difficult laryngoscope. Nevertheless, it's more valuable to apply the best model of this study, composed of various physiological measurements, for this prediction purpose.
... A meta-analysis found that the overall incidence of difficult intubation (DI) for normal patients is 6 2 . In addition, the rate of difficult laryngoscopy has been estimated between 6.8% to 9.6% during thyroid surgery 3,4 . ...
... After removal of duplicate studies, the search retrieved 245 articles that were retrieved for further examination after inspecting titles and abstracts. After reviewing these, 20 full-text articles 3,4,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] were assessed for eligibility and six were excluded (one pediatric trial, one review and four studies based on advanced airway devices for tracheal intubation or surgical items) [23][24][25][26][27][28] . A total of 14 studies entered the qualitative analysis 3,4,11-22 but six of them were excluded because we were not able to extract relevant data 16,[18][19][20][21][22] . ...
... A total of 14 studies entered the qualitative analysis 3,4,11-22 but six of them were excluded because we were not able to extract relevant data 16,[18][19][20][21][22] . Therefore, eight studies, including a total of 5853 patients, were considered in the final quantitative analysis 3,4,[11][12][13][14][15]17 . ...
Background:
Airway management is a fundamental goal for the anesthesiologist. The rate of difficult laryngoscopy in patients undergoing thyroid surgery ranges from 6.8% to 9.6%. An accurate and detailed preoperative evaluation of the airway seems to be a promising tool to predict a potentially difficult airway management. We aimed to identify possible risk factors and physical findings that predict difficult intubation in thyroid surgery.
Methods:
MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) were analysed, and the reference lists from the retrieved articles and previous reviews were searched for additional studies. Difficult intubation was defined as Cormack and Lehane grade ≥ 3 or Intubation Difficulty Scale score > 5 by direct laryngoscopy. Studies that used advanced airway devices or ultrasound-based airway management were excluded. Gender, Mallampati score, interincisor gap, thyromental distance, body mass index, tracheal deviation, histology, mediastinal goiter, mandibular protrusion, neck circumference and neck movement were evaluated. Qualitative analysis has been conducted in case of insufficient data for an appropriate meta-analysis.
Results:
Eight studies that evaluated the accuracy of clinical findings for identifying difficult intubation in thyroid patients were reviewed (5853 patients). Two authors independently screened articles, extracted data and assessed risk of bias. 7.21% [95% CI, 6.57% - 7.91%] of patients undergoing thyroid surgery were difficult to intubate. The physical examination findings that best predicted a difficult intubation included Mallampati score ≥ 3 (positive odds ratio 4.75 [95% CI, 2.22-10.12]); shorter thyromental distance (thresholds ranging from < 6.5 - < 6 cm; OR 3.64 [95% CI, 1.9-7.01]); 'low' interincisor gap, defined as a critical distance between incisors (ranging from < 3.5 - < 4.4 cm; odds ratio 2.57 [95% CI, 1.83-3.62]); presence of tracheal deviation (positive odds ratio, 2.06 [95% CI, 1.58-2.69]); body mass index > 30 kg/m2 (odds ratio 1.95 [95% CI, 1.20- 3.15]) and males (odds ratio 1.54 [95% CI, 1.21-1.95]). Histological examination positive for cancer didn't increase the risk for difficult intubation. For mediastinal goiter, mandibular protrusion, neck circumference and neck mobility only a qualitative analysis was performed.
Conclusions:
In thyroid patients, the presence of high Mallampati score, shorter thyromental distance, interincisor gap, tracheal deviation (the unique thyroid pathology linked parameter), obesity and male gender were risk factors for difficult intubation. However, all these significant parameters should be used in preoperative assessment to anticipate difficult intubation in thyroid surgery.
