Comparison of Modified Mallampati Classification in Supine and Sitting Positions to Predict Difficult Tracheal Intubation in Diabetic Patients

Background

Airway management of patients with long-standing diabetes poses a major challenge for anaesthesiologists due to stiff joint syndrome affecting the atlanto-occipital joint. In certain cases requiring immobilization, the Mallampati test must often be performed in the supine position for obvious reasons.

Objectives

Hence, we determined the diagnostic precision (sensitivity and specificity) of the modified Mallampati test in sitting and supine positions among the diabetic population in predicting difficult tracheal intubation.

Methods

A single-center prospective observational study on adult diabetic patients undergoing general anesthesia and orotracheal intubation was carried out. An observer recorded the modified Mallampati in the sitting posture during the pre-anesthetic examination. The Mallampati in the supine position was determined while in the operating room, and the difficulty of intubation was noted, and diagnostic precision was calculated. The main objective was to predict a difficult airway by calculating the sensitivity, specificity, positive predictive value, and negative predictive value.

Results

Out of the 150 participants, Mallampati grading in a sitting position was correctly able to identify 42.5% of difficult intubation cases, whereas it was 97.5% with Mallampati in the supine position. Mallampati grading in the sitting position was able to correctly identify 89.1% of easy intubation cases, which was 63.6% with Mallampati in the supine position. The correlation of Mallampati in the supine position with CL grading was statistically significant (P < 0.001).

Conclusions

Among diabetic patients, the modified Mallampati test in the supine position can be considered a more accurate and sensitive predictor of difficult intubation than the sitting posture.

Success rates of endotracheal intubation using the standard method versus the modified-ramped position

Background

The sniffing position used in intubation has disadvantages, including suboptimal glottic view, respiratory problems, increased risk of aspiration, and pain. In this regard, we have proposed new conditions to facilitate intubation and tube placement in patients with a Mallampati score higher than 2, by introducing a new position called the modified rapid airway management positioner (RAMP) position. The authors compared various parameters to improve intubation conditions between these two positions.

Methods

This intervention is a randomized clinical trial study, with a random sampling method that divides the patients into two groups: a control group placed in the standard position (S) and an intervention group placed in the modified (M) RAMP position. An anesthesiologist performed intubation. In group (S), patients were placed in the supine position as usual, and a pillow with a height of 10 cm was placed under their heads. In group (M), the patients were placed in the supine position on a modified RAMP with a triangular shape, 15 cm in height, and 80 cm in length, at a 30° angle. The pillow had lengths of 20 and 80 cm.

Results

In the present study, 112 patients were investigated, consisting of 58 women (51.8%) and 54 men (48.2%). The intubation time in the intervention group using the modified RAMP roll technique was significantly shorter (51.25 s) compared to the control group using the standard method (88.39 s) (P=0.019).

Conclusion

The results of the study showed that the modified RAMP roll improved the general conditions of intubation and led to a better view of the glottis in direct laryngoscopy. This is a very important aspect of intubation, and with a better view of the pharynx and glottis, the intubation procedure can be performed with higher quality, reducing the number of intubation attempts and the duration of the procedure.

Airway Management: Difficulty of Intubation and Range of Movement of the Thyroid Cartilage

PURPOSE

Difficult endotracheal intubation has been associated with a number of anatomic factors. According to our experience, the range of movement of thyroid cartilage can be used as a useful test to determine the difficulty in endotracheal intubation. The aim of this study was to evaluate the association between the range of movement of thyroid cartilage and difficulty in intubation.

DESIGN

Cross-sectional study.

METHODS

This study was carried out on 400 patients at (Shohada Ashayer Hospital, Khorramabad). After obtaining consent letters from the patients who were between 18 and 60 years of age, the patients underwent general anesthesia. The participants were evaluated by Mallampati and other evaluating tests. The range of movement of thyroid cartilage from the midline was measured and recorded.

FINDINGS

There were significant correlation between the range of movement of thyroid cartilage and thyromental distance. In addition, in patients with Cormack-Lehane class 1, the mean range of movement of thyroid cartilage was significantly more than the patients with Cormack-Lehane class 3 and 4.

CONCLUSIONS

The outcomes of our study indicate that the range of movement of thyroid cartilage can be used for predication of difficult intubation. However, further randomized trials should be conducted in this regard.

Comparison of anthropometric and conic beam computed tomography measurements of patients with and without difficult intubation risk according to modified mallampati score: New markers for difficult intubation

Background

The aim of this study was to compare the anthropometric and cone beam computed tomography (CBCT) measurements taken from risk-free and risky groups by using the modified Mallampati score (MMS).

Patients and Methods

A total of 176 volunteers between the ages of 18 and 65 in four different MMS classes were included in the study. The patients in classes MMS I and MMS II were accepted as risk-free and the patients in classes MMS III and MMS IV were accepted as risky for intubation. The Mann-Whitney U test was performed on the data to compare the anthropometric and radiological measurements taken from the risk-free and risky groups. A receiver operating characteristic (ROC) analysis was applied to the parameters that had a statistically significant difference.

Results

According to the analysis results, statistically significant differences were found in the neck circumference (NC), maximum interincisal distance (MID), thyromental distance (TMD) and sternomental distance (SMD) of the anthropometric measurements of men and women between the risk-free and risky groups (P < 0.05). In terms of CBCT measurements, the thickness of the tongue (TT), distance between the uvula and posterior wall of pharynx (U-Ph), distance between posterior nasal spine and nasopharynx (Snp-Nph) and length of the epiglottis (LE) were found to have statistically significant differences between the risk-free and risky groups of men and women (P < 0.05).

Conclusion

The NC, MID, TMD and SMD anthropometric measurements and TT, U-Ph, Snp-Nph and LE radiologic measurements were found to support MMS, which is one of the most widely used bedside intubation prediction tests. In addition to the inclusion of CBCT for intubation prediction, U-Ph and Snp-Nph radiologic measurements were added as difficult intubation markers.

Would modified mallampati score be relevant? Clinical trial

BACKGROUND

Obesity is a highly prevalent condition worldwide that aggravates symptoms of already existing conditions such as asthma and COPD. The limited effectiveness of inhaled medications in these individuals may be related to anatomic characteristics of their upper airways, mainly due to compressive factors.

METHODS

Controlled clinical trial with obese and nonobese individuals. The following variables were evaluated: anthropometric characteristics, Lung and airway deposition of radiolabeled aerosol (pulmonary scintigraphy), upper airways anatomy (CT scans), and modified Mallampati score.

RESULTS

29 subjects (17 nonobese and 12 obese) participated. Obese volunteers presented 30% lower aerosol lung deposition compared to nonobese. Moreover, obese subjects Mallampati classification of 4 presented an aerosol lung deposition two times lower than nonobese subjects (p = 0.021). The cross-sectional area of the retropalatal region and retroglossal region were lower in obese patients (p < 0.05), but no correlation to aerosol lung deposition was observed. BMI was associated with 32% of the variance of lung deposition (p < 0.001; β -0.28; 95% CI -0.43 to -0.11).

CONCLUSION

High BMI correlated to reduced percentage lung deposition. Also, modified Mallampati class 4 was even more detrimental to aerosol delivery into the lungs. Obese subjects have narrower upper airways, compared to nonobese, but this is not reflected in higher radiolabeled aerosol impaction into their oropharynx and does not predict the percentage of lung deposition in this group.

CLINICAL TRIAL REGISTRATION

NCT03031093 (clinicaltrials.org).

The anesthesia airway evaluation: Correlation with sleep endoscopy findings

PURPOSE

Drug-induced sleep endoscopy (DISE) is a cost-effective, safe, and reliable tool to evaluate obstructive sleep apnea (OSA) patients by revealing upper airway sites, patterns, and severity of obstruction. DISE provides valuable data because reliable evaluation of the OSA airway while awake has remained elusive. Few studies (with mixed results) have analyzed the correlation between pre-operation, awake airway assessments routinely performed by anesthesia and DISE results.

METHODS

Preoperative anesthesia evaluation records and subsequent DISE reports were obtained for 99 adult patients undergoing DISE between 2016 and 2018. All patients carried the diagnosis of OSA, based on polysomnography. Anesthesia-collected variables were compared with DISE findings in an effort to determine if commonly-utilized physical exam findings correlated to patterns of upper airway collapse observed on sleep endoscopy.

RESULTS

Most anesthesia preoperative evaluation variables were not found to be predictive of any identifiable patterns of collapse on DISE, including Mallampati score, ability to prognath, and overall airway assessment score. Obesity did not correlate with circumferential collapse at the velopharynx, or to multi-level collapse. Thyromental distance <6.5 cm was found to be statistically correlated to total epiglottic collapse (E = 2+). Friedman tongue position scores were found to be correlated to velopharyngeal collapse (p < 0.05).

CONCLUSIONS

Anesthesia airway assessment algorithms and physical exam findings do not correlate well with findings on sleep endoscopy. DISE remains the gold standard for evaluating levels of collapse and operative planning in the OSA population.

Validity of thyromental height test as a predictor of difficult laryngoscopy: A prospective evaluation comparing modified Mallampati score, interincisor gap, thyromental distance, neck circumference, and neck extension

Background and Aims:

Thyromental height test (TMHT) is a recently described anatomical bedside screening tool in predicting difficult laryngoscopy. It has been shown to be more accurate than the modified Mallampati score, thyromental distance (TMD), and sternomental distance with regard to sensitivity and positive predictive value (PPV). Airway assessment studies based on the anatomic parameters of the upper airway are limited in the subcontinent population. We attempted this study to evaluate and validate the predictive value of TMHT at 50 mm in an Indian population in predicting difficult laryngoscopy.

Methods:

This prospective observational study was conducted in a tertiary teaching hospital on 340 patients. TMHT along with other bedside predictors of difficult intubation, including modified Mallampati score, interincisor gap (IIG), TMD, neck circumference (NC), and neck extension were assessed. We compared the sensitivity, specificity, PPV, negative predictive value (NPV), and diagnostic accuracy of TMHT with other bedside tests such as the modified Mallampati score, IIG, TMD, NC, and neck extension individually in predicting difficult laryngoscopy. Any Cormack and Lehane's intubation grade II b and above was considered to be difficult laryngoscopy.

Results:

TMHT had the highest sensitivity (84.62%) and specificity (98.97%), and had the most PPV (88%) and NPV (98.63%) when compared with the modified Mallampati score, IIG, TMD, NC, and neck extension. TMHT was followed by the modified Mallampati score and IIG.

Conclusion:

TMHT appears promising as a single anatomical measure to predict the risk of difficult laryngoscopy, however, validation will require further studies in more diverse patient populations.

Are physician assistant and patient airway assessments reliable compared to anesthesiologist assessments in detecting difficult airways in general surgical patients?

Background

Airway management remains one of the most important responsibilities of anesthesiologists. Prediction of difficult airway allows time for proper selection of equipment, technique, and personnel experienced in managing patients with difficult airway. Face to face preoperative anesthesia interviews are difficult to conduct as they necessitate patients traveling to the clinics, and, in practice, are usually conducted in the morning of the procedure by the anesthesiologist, when identification of predictors of difficult intubation may lead to schedule delays or case cancelations. We hypothesized that an airway assessment tool could be used by patients or physician assistants to accurately assess their airways.

Methods

We administered an airway assessment tool, which had been constructed in consultation with a psychometrician and revised after non-medical layperson feedback, to 215 patients presenting to the preoperative clinic for evaluation. Separately, patients had the airway exam performed by a physician assistant and an anesthesiologist. Agreement was compared using kappa.

Results

We found good agreement between observers only on "can you put three fingers in your mouth?" (three-way kappa = .733, p < 0.001) and poor agreement on Mallampati classification (three-way kappa = .195, p < 0.001) and "Can you fit three fingers between your chin and your Adam's Apple?" (three-way kappa = .216, p < 0.001). The agreements for the other questions were mostly fair. Agreements between patients and anesthesiologists were similar to those between physician assistants and anesthesiologists.

Conclusions

Neither the patients' self-assessments nor the physician assistants' assessments were adequate to substitute for the anesthesiologists' airway assessments.

Predicting Difficult Laryngoscopy and Intubation With Laryngoscopic Exam Test: A New Method

Airway assessment is fundamental skill for anesthesiologists and failure to maintain a patient's airway is the tremendous cause of anesthesia-related morbidity and mortality. None of the tests which have recommended for predicting difficult intubation stands out to be the best clinical test or have high diagnostic accuracy. Our study aimed to determine the utility of a new test as "laryngoscopic exam test (LET)" in predicting difficult intubation. Three hundred and eleven patients aged 16-60 years participated and completed the study. Airway assessment was carried out with modified Mallampati test, upper lip bit test and LET preoperatively, and Cormack and Lehane's grading of laryngoscopy were assessed during intubation as a gold standard, and difficult laryngoscopy was considered as Cormack and Lehane's grade ΙΙΙ or ΙV of laryngoscopic view. The incidence of difficult intubation was 6.1%. The LET showed higher sensitivity, specificity, and accuracy (P<0.05), without revealing significant differences among three tests (P=0.375). The LET is a simple bedside test and an alternative method for predicting difficult intubation.

Friedman tongue position: age distribution and relationship to sleep-disordered breathing

PURPOSE

Friedman tongue position (FTP) may play an important role in the evaluation of children with sleep-related breathing disorders (SRBD), but there are no previous data on FTP distribution by age. The objective of the current study was to determine the distribution of FTP by age and examine the relationship between FTP and snoring in children.

METHODS

Prospective cross-sectional study of 199 children (mean age, 6.8 years; 59% male) had tongue position assessed by FTP as part of their clinical examination of the oral cavity during routine ENT visits at a tertiary care children's hospital. The FTP and snoring frequency of participants was examined across the entire age range as well as by comparing those older (middle childhood and above) and younger than 5 years of age.

RESULTS

Tongue position did not correlate with age or snoring frequency. The proportion of children with FTP III/IV was not significantly different in children younger than five years of age compared to older than five. Habitual snoring was not associated with having a higher FTP. Among children who snored <3 times per week, those who had previously undergone tonsillectomy did have higher FTP compared to those who had not (p=0.007). BMI-%-for-age was significantly correlated with FTP (p=0.003). The percent of children having FTP class III/IV differed significantly between ethnicities (22% of whites, 26% of others, 45% of hispanics, 53% of African-Americans; p=0.011). Inter-rater reliability among pediatric otolaryngologist was excellent (kappa=0.93, p<0.001).

CONCLUSIONS

There does not appear to be an association between FTP with age or snoring frequency in children. The excellent inter-rater reliability for FTP among pediatric ENT providers suggests the null findings are not due to rater bias. These findings may serve as an important reference for those studying the role of tongue position in pediatric SRBD and complement previous studies examining FTP among children with known OSA or snoring.

Sensitivity of the Combination of Mallampati Scores with Anthropometric Measurements and the Presence of Malignancy to Predict Difficult Intubation

OBJECTIVE

The aim of this study was to determine the combinations of the Mallampati test and anthropometric measurements with the highest selectivity value. In addition, we aim to identify a possible correlation between head circumference measurement, the presence of malignancy and difficult intubation.

METHODS

Patients who were scheduled to undergo elective surgery under general anaesthesia, who fell into Group 1-2 according to ASA criteria and were between the ages of 18-70 years were included in the study. Patients with Cormack-Lehane scores of 3-4 were considered to be difficult intubations. Thyromental distance, sternomental distance, mandibular distance, neck length, neck circumference and head circumference were measured during the anthropometric measurements.

RESULTS

According to the ROC analysis, there was a significant difference in the thyromental distance, sternomental distance, neck length, neck circumference and head circumference between the easy and difficult intubation groups (p<0.05). The incidence of difficult intubation was 8.3% in patients with non-head-neck malignancies, whereas the incidence was 7.1% in patients without any malignancies. The difference between these groups was not statistically significant (χ(2)=0.101; p=0.751).

CONCLUSION

To predict the incidence of difficult intubation, the test with the highest selectivity and highest positive predictive values was the combination of Mallampati-thyromental distance. We believe that the head circumference and neck length measurement, in addition to the current anthropometric measurements, may be crucial to predict the incidence of difficult intubations. In addition, we believe that the anticipation of difficult intubations in patients with non-head-neck malignancies is not different from the normal population.

Risk Factors Assessment of the Difficult Intubation using Intubation Difficulty Scale (IDS)

BACKGROUND

The major responsibility of anaesthesiologist is to maintain adequate gas exchange in his patients in all circumstances and this require that patency of upper airway is constantly maintained. Problems with upper airway management are among the most frequent causes of anaesthetic mishaps. Using intubation difficulty scale (IDS) we made an attempt to objectively assess the predictors of difficult intubation. We assessed classical bedside tests such as modified Mallampati test, Thyromental distance test and also neck extension test.

METHODS

We prospectively observed 400 patients undergoing general anaesthesia with endotracheal intubation, for each patient intubation difficulty score was recorded during intubation. Risk factors assessment of difficult intubation done using IDS. Risk factor assessed includes modified mallampati class III and IV, thyromental distance ≤ 6cm and neck extension < 5cm. Patients were categorised as Easy intubation (IDS, 0 to 2), slightly difficult intubation (IDS, 3 to 4) and difficult intubation (IDS 5). Preoperative airway assessment was done by thyromental distance measurement, neck extension measurement and modified mallampati test. Data was analysed using Receiver operating characteristic curve (ROC) and area under curve (AUC) for each test computed. p<0.05 was considered significant.

RESULTS

The incidence of difficult intubation was 8% and there were no failure to intubate the trachea. The AUC were as follows: modified Mallampati test 0.473 (p<0.005), Thyromental distance test 0.753 (p<0.005) and neck extension test 0.768 (p<0.005).

CONCLUSION

The results indicate that neck extension test is strongest predictor of difficult intubation (IDS≥5) in comparison to Thyromental test and modified mallampati test.