Comparison of sonography and computed tomography as imaging tools for assessment of airway structures

Computed Tomography-Based Predictors of Difficult Intubation in Oral and Maxillofacial Surgery Patients

BACKGROUND

The incidence of difficult airway is higher in oral and maxillofacial surgery (OMS) than in general surgery. Current predictors, including clinical tools like the LEMON (Look Externally, Evaluate Mallampati Classification, Obstruction, Neck Mobility, Motion of Jaw) score, are often inaccurate, leading to underdiagnosis and increased risks to patient safety.

PURPOSE

This study aimed to identify computed tomography (CT) findings associated with difficult intubation in OMS patients.

STUDY DESIGN, SETTING, SAMPLE

This prospective cohort study was conducted at the Shanghai Ninth People's Hospital from October 2018 to October 2021 and included patients undergoing OMS under general anesthesia. Exclusion criteria included individuals who received regional anesthesia, had contraindications to mask ventilation, lacked preoperative CT imaging, or did not provide informed consent.

PREDICTOR VARIABLES

The predictor variables were 21 midsagittal plane CT parameters and five 3-dimensional airway reconstruction parameters.

OUTCOME VARIABLE

The outcome variable was ease of intubation, categorized as difficult intubation (grade III or IV laryngeal view under direct laryngoscopy) and easy intubation (grade I or II laryngeal view under direct laryngoscopy).

COVARIATES

Covariates included demographic variables (age, weight, body mass index, and sex) and anatomical variables (modified Mallampati classification, hyoid thyroid cartilage distance, hyoid mental distance, thyromental distance, atlanto-occipital joint extension, and interincisor distance).

ANALYSES

Least absolute shrinkage and selection operator was used to select significant variables. Logistic regression was then used to construct the predictive model. The model's performance was evaluated using receiver operating characteristic curve.

RESULTS

The study included 630 patients, with 35.2% experiencing difficult intubation. The model was composed of 10 midsagittal plane and two 3-dimensional airway reconstruction parameters from CT images, with area under the curve values of 0.78 in the training cohort (n = 336) and 0.76 in the validation cohort (n = 72). In the validation cohort, the model achieved a sensitivity of 0.74 and a specificity of 0.75. In contrast, the area under the curve value of LEMON score was 0.62.

CONCLUSIONS AND RELEVANCE

This study developed a CT-based model that identifies patients at risk of difficult intubation in OMS, outperforming the LEMON score and underscoring the relevance of CT parameters, particularly those involving the tongue, uvula, and hyoid bone, in guiding clinical decision-making.

Dynamic behavior of the oropharynx airway during deep breath in patients with obstructive sleep apnoea hypopnoea syndrome observed by ultrasonography

This study aimed to determine whether ultrasonography can be used to assess the oropharyngeal airway in patients with obstructive sleep apnoea hypopnoea syndrome (OSAHS). 104 patients with OSAHS and 104 sex-, body mass index (BMI)-, and age-matched healthy subjects underwent oropharynx airway assessment using ultrasound. The dimensional changes of the oropharynx were monitored, and sonographic measurements of the airway lumen were obtained during deep breathing. Measurements were compared between groups. All suspected patients underwent Polysomnography in the sleep laboratory. OSAHS was defined as apnea-hypopnea index (AHI) > 5 events/h. Adequate visualization of oropharyngeal dimensional changes was obtained in 95.19% of patients with OSAHS and 100% of healthy subjects. The anteroposterior diameter (AP) and lateral diameter (LAT) of the oropharyngeal airway of patients with OSAHS were smaller than those of healthy subjects at the end of deep inspiration and expiration (all P < 0.05). Patients with OSAHS had greater lateral airway dimensional changes than the anterior-posterior dimension changes (P < 0.001). The AP/LAT ratio of OSAHS at the end of deep inspiration was higher than that of healthy subjects (P = 0.012). Ultrasonography can detect the dimensional changes of the oropharyngeal airway in patients with OASHS during deep breathing. Patients with OASHS have a smaller airway size, a more circular configuration, and a more significant change of diameter in oropharynx airway than healthy subjects.

Prediction of difficult mask ventilation in Thai adult patients undergoing elective surgery using ultrasound of distance from skin to hyoid bone, and from skin to thyroid isthmus: a prospective cohort observational study

BACKGROUND

A previous study showed that airway ultrasound, specifically the distance from the skin to the hyoid bone (DSHB), may be correlated with a higher risk of difficult mask ventilation (DMV). However, the study was conducted in Italy and lacks data for the Asian and Thai populations. This study aimed to predict DMV using pre-operative ultrasonography to measure the DSHB and from the skin to the thyroid isthmus (DSTI) in Thai patients undergoing elective surgery under general anesthesia.

METHODS

In total, 189 patients who underwent general anesthesia during elective surgery were enrolled in this prospective cohort observational study. Pre-operative physical examinations and airway evaluations were performed as usual. Airway ultrasound was performed to measure DSHB and DSTI before the anesthetic procedure. Anesthesiologists and nurse anesthetists performed bag-and-mask ventilation. DMV was assessed and recorded according to Han's mask ventilation classification in which DMV-0 indicates no attempt at mask ventilation; DMV-I indicates successful ventilation by mask; DMV-II indicates ventilation by mask with oral airway/adjuvant ventilation; DMV-III indicates that ventilation required two providers; and DMV-IV indicates the patient's inability to undergo mask ventilation.

RESULTS

Thirty (17%) patients were classified as having DMV-0, and DMV-I, II, and III classifications were observed in 126(67%), 18(10%), and 12(6%) patients, respectively. None of the patients were classified as DMV-IV. The DSHB medians were 0.4(0.3-0.6), 0.7(0.5-1), 0.7(0.6-0.8), and 0.6(0.3-0.9) cm in DMV-0, I, II, and III, respectively (p < 0.001). The DSTI medians were 0.9(0.8-1.1), 0.8(0.7-1.1), 0.7(0.6-0.9), and 0.8(0.8-1.4) cm for DMV-0, I, II, and III, respectively (p = 0.041). Multivariate logistic regression indicated that the following factors were associated with difficult mask ventilation (DMV-III): male sex, modified Mallampati classification III, edentulousness, DSHB, and DSTI, with an area under the curve of 0.89.

CONCLUSIONS

This study showed that airway ultrasonography to determine DSHB and DSTI during patients' routine physical examinations significantly improved the prediction of DMV. Patients classified as having DMV-III require prompt management for airway difficulties. However, the individual factors DSHB and DSTI alone are insufficient to predict DMV.

TRIAL REGISTRATION

Registration number: TCTR2020093002.

Evaluation of ultrasound measured tongue thickness, tongue thickness-thyromental distance ratio, and skin-to-epiglottis distance in predicting unanticipated difficult laryngoscopy

Background and Aims

The contemporary literature review suggests upper airway ultrasound can help us to diagnose an unanticipated difficult airway before laryngoscopy. The primary objective of this study was to compare ultrasonography (USG) and clinical airway indices across easy and difficult laryngoscopy groups.

Material and Methods

This prospective observational study included 258 patients scheduled to undergo surgery under general anesthesia with endotracheal intubation. Ultrasonographic upper airway parameters, viz., tongue thickness (TT), skin-to-epiglottis distance (DSE), and tongue thickness to thyromental distance ratio (TT/TMD) were measured. Patients were identified as easy or difficult laryngoscopy groups based on their Cormack Lehane (CL) grading.

Results

Out of 258 patients, 20 (7.75%) had difficult laryngoscopy, and 238 (92%) had easy laryngoscopy. The USG measured TT mean, and median values were 6.16 ± 0.39 [6.10] cm in difficult and 5.41 ± 0.36 [5.40] cm in easy laryngoscopy groups. The USG measured mean and median value of DSE were 2.75 ± 0.09 [2.74] in difficult and 2.27 ± 0.23 [2.27] in easy laryngoscopy groups. The ratio of TT/TMD with mean and median values of 0.98 ± 0.07 [0.99] in difficult and 0.84 ± 0.13 [0.82] in easy laryngoscopy. Using the inputs, the diagnostic accuracy of the ultrasound-measured significant variables was calculated in terms of their area under the curve using the receiver operating characteristic curve.

Conclusions

This study revealed a relationship between sonographic measurements like TT, DSE, and TT/TMD ratio for easy and difficult laryngoscopy identification. Including these sonographic parameters and their cut-off values may enhance our ability to predict an unanticipated difficult laryngoscopy.

Role of ultrasonography in upper airway assessment: A comparison with computerized tomography measurements

INTRODUCTION

This study aimed to compare ultrasonography (US) measurements of the upper airway to computerized tomography (CT) measurements. Our study's primary outcome is to research the accuracy of US measurements in the evaluation of upper airway diameters when CT is taken as the gold standard; the secondary outcome is to determine the time required to obtain US measurements.

METHODS

This prospective study included patients ≥18 years old that had undergone thoracic or neck CT due to current clinical necessity. The US measurement for each patient was performed by two researchers with different levels of experience, both of whom were blinded to each other and the CT measurements. Measurements were obtained from the vocal cords and subglottic region. The duration of the US performance was also recorded.

RESULTS

The US and CT measurements were obtained from 94 patients. Concordance between US and CT measurements was found in the Bland-Altman analysis, with a mean -0.05 mm difference for vocal cord diameter and -1.2 mm for subglottic diameter. The intra-class correlation coefficients (ICC) between the CT and US measurements were 0.993, and 0.609 for vocal cord and subglottic diameter measurements, respectively. The ICC between US performers was 0.992 for vocal cord diameter and 0.959 for subglottic diameter. The US's mean time for vocal cord diameter measurement was 38 ± 23 s, and the mean time for subglottic diameter measurement was 49 ± 30 s.

CONCLUSION

The concordance between US and CT measurements is high and the measurements of different practitioners with different experience levels are compatible with each other.

Preoperative airway ultrasound assessment in the sniffing position: a prospective observational study

BACKGROUND

Clinical airway screening tests intend to predict difficult airways, but none have a high predictive value. Recent systematic reviews correlate ultrasound with difficult laryngoscopy. This study aimed primarily to correlate ultrasound measurements of anatomical upper airway structures in the sniffing position with difficult direct laryngoscopy. The secondary aim was to observe gender-based differences.

METHODS

This prospective, cross-sectional, single-center observational study included 209 patients requiring general anesthesia for elective surgery. Preoperatively, we performed six clinical airway assessments and three ultrasound measurements, which were the Distance from Skin to the Hyoid Bone (DSHB), to the Epiglottis (DSE), and to the anterior commissure of the vocal cords (DSAC) in a sniffing position. Benumof's criteria for the "best view at the first attempt" for direct laryngoscopy assessed the difficulty of laryngoscopy.

RESULTS

The distance from skin to the epiglottis was the best predictor of direct difficult laryngoscopy (defined as Cormack-Lehane grade ≥ 2b) with a minimum thickness cut-off at 2.70 ± 0.19 cm (sensitivity 91.3%; specificity 96.9%). The skin to the hyoid bone distance cut-off was 1.41 ± 0.30 cm with moderate correlation (sensitivity 80.4%; specificity 60.1%). No correlation was found for the distance to the anterior commissure of the vocal cords. In women compared to men, the skin to the epiglottis distance was more sensitive (92.3% vs. 90.9%) and specific (98.8% vs. 95.2%).

CONCLUSIONS

DSE in the sniffing position is the most reliable parameter for preoperative airway ultrasound assessment in the Caucasian population, with higher sensitivity and specificity in women, and might be considered as an independent predictor for direct difficult laryngoscopy.

Supraglottic Airway Devices with Vision Guided Systems: Third Generation of Supraglottic Airway Devices

Supraglottic airway devices are currently widely used for airway management both for anaesthesia and emergency medicine. First-generation SADs only had a ventilation channel and did not provide protection from possible aspiration of gastric content if regurgitation occurred. Second-generation SADs are equipped with a gastric channel to allow the insertion of a gastric catheter and suctioning of gastric content. Additionally, the seal was improved by a change in the shape of the cuff. Some second-generation SADs were also designed to allow for intubation through the lumen using fiberscopes. Although the safety and efficacy of use of SADs are very high, there are still some issues in terms of providing an adequate seal and protection from possible complications related to misplacement of SAD. New SADs which allow users to choose the insertion scope and control the position of SAD can overcome those problems. Additionally, the Video Laryngeal Mask Airway may serve as an endotracheal intubation device, offering a good alternative to fibre-optic intubation through second-generation SADs. In this narrative review, we provide knowledge of the use of video laryngeal mask airways and the possible advantages of introducing them into daily clinical practice.

Comparison of Ultrasound Examination and Fiberoptic Laryngoscopy for Confirmation of Laryngeal Mask Airway Placement

OBJECTIVES

1) To compare ultrasound (US) examination and fiberoptic laryngoscopy (FOL) for confirmation of laryngeal mask airway (LMA) placement. 2) To evaluate the necessity for reinsertion of LMA based on FOL.

METHODS

This prospective observational study included 100 adult patients of American Society of Anesthesiologists (ASA) Grade I and II, undergoing elective surgery under General Anesthesia requiring Proseal LMA™ placement as an airway device. LMA placement was first confirmed by clinical tests. Clinically acceptable patients were further assessed by US and categorized as acceptable (US-A) or unacceptable (US-U) and again by FOL as (FOL-A and FOL-U). Categorical variables presented in number, percentage (%), and continuous variables presented as mean ± SD and median. Inter-rater kappa agreement was used to find out the strength of agreement of acceptability between FOL and US.

RESULTS

The LMA placement was clinically acceptable in 82% of patients on first attempt. FOL had 63% (FOL-A) acceptable LMA placement as compared with US examination which had 56% (US-A). In 85% of patients, US and FOL findings were in good agreement with each other for LMA placement (κ = 0.690 and P < .05). In all patients of FOL of unacceptable (FOL-U) category (37%), LMA was replaced with endotracheal tube.

CONCLUSION

US provides a safe, non-invasive, and real-time dynamic assessment with 85% diagnostic accuracy for confirmation of LMA placement as compared with FOL.

Improvement in Validity and Reliability of Airway Assessment Using Ultrasonography by Novice Personnel: A Learning Cohort Study

PURPOSE

To assess improvements in the validity and reliability of novices' skills in performing ultrasonography for airway assessment.

PATIENTS AND METHODS

A learning cohort study was conducted with 20 anesthesiology residents and 10 volunteers in the Department of Anesthesiology, Faculty of Medicine, Prince of Songkla University. The four parameters of airway assessment were soft tissue thickness at the level of 1) hyoid bone (STT-HY), 2) true vocal cords (STT-VC), 3) thyroid isthmus (STT-TI), and 4) suprasternal notch (STT-SN). The magnitude of discrepancies between the residents' and experienced anesthesiologists' measurements was evaluated over the sequence of measurements in the 10 volunteers.

RESULTS

The mean ultrasonic measurements of STT-HY by the experienced anesthesiologists and residents were significantly different (11.09 ± 3.14 mm vs 8.53 ± 3.02 mm, respectively; P = 0.008), whereas measurements of STT-VC, STT-TI, and STT-SN were not (7.18 ± 1.70 vs 7.14 ± 1.93, P = 0.32; 7.81 ± 2.14 vs 7.73 ± 2.19, P = 0.62; and 11.32 ± 3.33 vs 10.30 ± 3.02, P = 0.35, respectively). The mean discrepancy between the residents' and experienced anesthesiologists' measurements was close to zero throughout the sequence of measurements of STT-TI and STT-VC. However, the residents' measurements of STT-HY and STT-SN were considerably lower than those of anesthesiologists. The range of discrepancies between residents and experienced anesthesiologists in each sequential measurement was wide for all measurements, particularly for the measurement values of STT-HY, and the standard deviation of the discrepancies did not decrease over the sequence of measurements.

CONCLUSION

Over the sequence of measurements for airway assessment in 10 volunteers by 20 residents in this learning trial, we found no evidence of improvement in measurement accuracy. Discrepancies between the residents' and anesthesiologists' measurements and the variability in discrepancy across residents were greatest in the measurement of STT-HY.

Anesthesia management for cesarean section in a pregnant woman with odontogenic infection: A case report

BACKGROUND

In recent years, people have paid more attention to oral health with the development of stomatology. Due to the various physiological changes during pregnancy, such as changing hormone levels and immune functions, oral diseases have a high incidence during pregnancy, and the prevention and treatment of oral diseases have also received the attention of both dentists and obstetricians. However, the anesthetic management of pregnant patients with oral disease, especially severe maxillofacial infections, and patients who need surgical treatment or have obstetric emergencies and need to terminate their pregnancy is not clear.

CASE SUMMARY

This article describes a parturient patient with a severe masseteric space infection who had an emergency cesarean section.

CONCLUSION

This case report aims to discuss the important anesthetic considerations for these patients.

Radiological versus traditional parameters for airway assessment: A comparison

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Value of laryngeal ultrasound in comparison with flexible laryngoscope in diagnosis of various laryngeal masses: a cross-sectional study

Background

The term "vocal cord mass" refers to any abnormal growth of the vocal cords. This may include nodules, cysts, polyps, or cancers. Hoarseness of voice is considered the most common symptom of laryngeal lesions. Ultrasound imaging has evolved into a valuable and effective technique for evaluating the head and neck region, including the larynx's structure. Our aim is to evaluate laryngeal ultrasound as an alternative technique to the flexible laryngoscope in the diagnosis and assessment of various laryngeal masses.

Results

The study included 30 males (57.7%) and 22 females (42.3%) who presented with hoarseness of voice. All patients had laryngeal ultrasonography, which was followed by flexible laryngoscopy. The most commonly affected cord was the left vocal cord (42.3%), followed by the right vocal cord (32.7%), and finally both of them (25%). The sensitivity of laryngeal ultrasonography was 88.5% compared to the gold standard flexible laryngoscopy (p value 0.031).

Conclusions

The laryngeal ultrasonography is a highly successful technique in the diagnosis and assessment of various laryngeal masses and could be complementary to flexible laryngoscopy in many cases, especially when laryngoscopy is contraindicated, with relatively high sensitivity in the detection of laryngeal masses.

Nasotracheal intubation for airway management during anesthesia

Nasotracheal intubation is used as a basic method for airway management, along with orotracheal intubation under anesthesia and intensive care. It has become an effective alternative method to orotracheal intubation with increased benefits of offering better mobility and surgical field in oral and maxillofacial surgery and possibly in trauma and critically ill patients. Nasotracheal intubation is performed through a relatively narrow nasal cavity; therefore, additional precautions are needed. Accordingly, nasotracheal intubation methods have evolved over the years with accumulated clinical experience and improved instruments to facilitate safe intubation with reduced complications. Therefore, in this review article, we summarize the basic anatomy of the nasal airways to clarify the precautions, delineate the history and development of various methods and instruments, and describe the indications, contraindications, complications, and preventive methods of nasotracheal intubation.

Ultrasound for assessment and follow-up of airway stenosis

BACKGROUND

Ultrasound is a reliable tool for airway assessment and management. We evaluated the accuracy of Ultrasound in the pre-procedure planning and follow-up evaluation of patients undergoing airway stenting for benign upper airway stenosis.

METHODS

This was a retrospective single center study on patients with benign upper airway stenosis treated with airway stenting. Ultrasound evaluated the characteristics of the stenosis (distance from vocal folds, diameter and length) before treatment and any complications after treatment; these results were then statistically compared with those obtained by computed tomography, taking the endoscopy as the reference method.

RESULTS

Twenty-seven patients were evaluated. Ultrasound was significantly correlated with endoscopy and computed tomography scan measurements as distance of stenosis from vocal folds (r=0.88; p<0.001 and r=0.87; p<0.001, respectively); diameter of the stenosis (r=0.97; p<0.001 and r=0.97; p<0.001, respectively); and length of the stenosis (r=0.97; p<0.001 and r=0.97; p<0.001, respectively). Four out of 27 (15%) patients presented complications after treatment as stent migration (n=2; 7%); stent obstruction (n=1; 4%), and granulation of vocal fold (n=1; 4%). All complications but granulation of vocal fold were correctly depicted by Ultrasound and Computed Tomography without significant difference in comparison to endoscopy (p=0.87) CONCLUSIONS: Ultrasound is a promising tool in assessment of airway stenosis and follow-up of patients after stenting; it may be routinely used in adjunction to computed tomography and/or endoscopy in this setting, if our results are corroborated by future larger study.

Anterior neck soft tissue measurements on computed tomography to predict difficult laryngoscopy: a retrospective study

Predicting difficult laryngoscopy is an essential component of the airway management. We aimed to evaluate the use of anterior neck soft tissue measurements on computed tomography for predicting difficult laryngoscopy and to present a clear measurement protocol. In this retrospective study, 281 adult patients whose tracheas were intubated using a direct laryngoscope for thyroidectomy were enrolled. On computed tomography, the distances from the midpoint of the thyrohyoid membrane to the closest concave point of the vallecular (membrane-to-vallecula distance; dMV), and to the most distant point of the epiglottis (membrane-to-epiglottis distance; dME) were measured, respectively. The extended distances straight to the skin anterior from the dMV and dME were called the skin-to-vallecula distance (dSV) and skin-to-epiglottis distance (dSE), respectively. Difficult laryngoscopy was defined by a Cormack-Lehane grade of > 2. Difficult laryngoscopy occurred in 40 (14%) cases. Among four indices, the dMV showed the highest prediction ability for difficult laryngoscopy with an area under the receiver operating characteristic curve of 0.884 (95% confidence interval 0.841–0.919, P < 0.001). The optimal dMV cut-off value for predicting difficult laryngoscopy was 2.33 cm (sensitivity 75.0%; specificity 93.8%). The current study provides novel evidence that increased dMV is a potential predictive indicator of difficult laryngoscopy.

Endotracheal intubation using a three-dimensional printed airway model in a patient with Pierre Robin sequence and a history of tracheostomy -a case report

Background

Pierre Robin sequence (PRS) patients have an increased risk of difficult intubation due to anatomical airway abnormalities, and intubation simulation with a three-dimensional (3D) printed airway model before anesthesia may facilitate safe airway management.

Case

We describe the case of a 6.5-year-old boy with a history of PRS (a triad of micrognathia, glossoptosis, and airway obstruction), tracheostomy, and subglottic fibrosis who required general anesthesia. Preparation for this potentially difficult intubation included estimation of endotracheal tube size using a 3D printed airway model derived from 3D computed tomography of the airway, which enabled successful endotracheal intubation via video laryngoscopy.

Conclusions

If general anesthesia is necessary in patients with dysmorphic features such as PRS and there is a history of tracheal pathology, the possibility of difficult intubation should always be considered and simulation of endotracheal intubation using a 3D printed model of the airway can be helpful clinically in such situations.

Application of Transcutaneous Laryngeal Ultrasonography in the Diagnosis of Vocal Fold Polyps

The aim of this study was to explore the value of transcutaneous laryngeal ultrasonography in the diagnosis of vocal fold polyps. From December 2016 to June 2019, 87 patients with vocal fold polyps diagnosed pathologically in the Otolaryngology Head and Neck Surgery Department of the Second Affiliated Hospital of Xi'an Jiaotong University were enrolled and examined by electronic laryngoscopy and percutaneous laryngeal ultrasound on the same day before operation. To observe the effect of calcification length as a percentage of thyroid cartilage at the glottic level on vocal fold display, the characteristics of ultrasound images of vocal fold polyps and the value of transcutaneous laryngeal ultrasonography in the diagnosis of vocal fold polyps were assessed. Among 87 patients, the calcification rate of thyroid cartilage at the glottic level was 33.3%. The differences in calcification rate and percentage of calcification length between males and females were statistically significant. The rate of detection of vocal folds decreased gradually with an increase in calcification length percentage. Imaging features of vocal fold polyps were hypo-echoic with a clear boundary and regular shape. The detection rates for circular and non-circular polyps were 92.0% and 70.6%. Ultrasound was more likely to detect circular than non-circular polyps; however, the difference was not significant. Transcutaneous laryngeal ultrasonography can identify the morphology and location of vocal fold polyps and is non-invasive and highly accurate. Therefore, it has the potential to be an effective supplement to laryngoscopy for initial screening and post-operative review of vocal fold polyps.

Point-of-care ultrasound in the preoperative setting

Point-of-care ultrasound (POCUS) is a widely used diagnostic tool, especially in emergency and critical care medicine, and it is increasingly being used in the perioperative setting. Its specific role in preoperative assessment of patients, however, has not yet been defined. While some data show innovative use of the technique in the preoperative setting, higher-level evidence to underscore potential advantages is still limited. We review and discuss a range of POCUS examinations which can potentially help anaesthesiologists in the preoperative clinic decide whether to perform additional testing, can assist in selecting the best anaesthetic approach, and can support perioperative and postoperative monitoring.

Pilot Study to Assess the Use of Ultrasound in Evaluating the Abnormal Pediatric Airway

In this study, we sought to explore the feasibility of using ultrasonography to evaluate airway anomalies in awake children with previous airway reconstruction. For the month of December 2018, we reviewed the medical records of patients aged <18 years old with prior airway reconstruction who had an outpatient appointment and a microlaryngoscopy and bronchoscopy within 24 hours of each other. Four patients met inclusion criteria and were enrolled. Sonographic airway images and measurements were obtained during the outpatient appointment and compared with those obtained during endoscopy. Ultrasound identified extraluminal stents and glottic, subglottic, and tracheal pathology. Subglottic measurements obtained sonographically were within 0.1 to 0.5 mm of the outer diameter of the appropriate endotracheal tubes. Ultrasound did not visualize tracheotomy tubes or posterolateral pathology. Our findings lay the foundation for expanding the role of ultrasound in pediatric airway assessment, keeping in mind its apparent inability to visualize posterolateral airway pathology.

Ultrasound is a reliable and faster tool for confirmation of endotracheal intubation compared to chest auscultation and capnography when performed by novice anaesthesia residents - A prospective controlled clinical trial

Background

Anesthesia trainee may initially take longer time to intubate and unintentionally place the endotracheal tube (ETT) in the esophagus. The present study determined if ultrasound is the fastest method of confirmation of correct placement of ETT compared to capnography, and chest auscultation in trainees.

Methods

First year anesthesia residents performed intubation in 120 patients recruited after ethical clearance and informed consent. Time to visualize flutter in trachea, double trachea sign, time to appearance of first and sixth capnography, and time to execute chest auscultation was noted.

Results

Ultrasonography was statistically fastest method to determine endotracheal intubation (36.50 ± 15.14 seconds) vs unilateral chest auscultation (50.29 ± 15.50 seconds) vs bilateral chest auscultation (51.90 ± 15.98 seconds) vs capnography first waveform (53.57 ± 15.97 seconds) vs capnography sixth waveform (61.67 ± 15.88 seconds).

Conclusion

When teaching endotracheal intubation to novice anesthesia residents using conventional direct laryngoscopy, ultrasonography is the fastest method to confirm correct ETT placement compared to capnograph and chest auscultation. Mentor can guide trainee to direct ETT towards trachea and can promptly detect esophageal intubation by double trachea sign.

Point-of-Care Ultrasound for Obstructive Sleep Apnea Screening: Are We There Yet? A Systematic Review and Meta-analysis

BACKGROUND

Perioperative diagnosis of obstructive sleep apnea (OSA) has important resource implications as screening questionnaires are overly sensitive, and sleep studies are expensive and time-consuming. Ultrasound (US) is a portable, noninvasive tool potentially useful for airway evaluation and OSA screening in the perioperative period. The objective of this systematic review was to evaluate the correlation of surface US with OSA diagnosis and to determine whether a point-of-care ultrasound (PoCUS) for OSA screening may help with improved screening in perioperative period.

METHODS

A search of all electronic databases including Medline, Embase, and Cochrane Database of Systematic Reviews was conducted from database inception to September 2017. Inclusion criteria were observational cohort studies and randomized controlled trials of known or suspected OSA patients undergoing surface US assessment. Article screening, data extraction, and summarization were conducted by 2 independent reviewers with ability to resolve conflict with supervising authors. Diagnostic properties and association between US parameters (index test) and OSA diagnosis using sleep study (reference standard) were evaluated. The US parameters were divided into airway and nonairway parameters. A random-effects meta-analysis was planned, wherever applicable.

RESULTS

Of the initial 3865 screened articles, 21 studies (7 airway and 14 nonairway) evaluating 3339 patients were included. Majority of studies were conducted in the general population (49%), respirology (23%), and sleep clinics (12%). No study evaluated the use of US for OSA in perioperative setting. Majority of included studies had low risk of bias for reference standard and flow and timing. Airway US parameters having moderate-good correlation with moderate-severe OSA were distance between lingual arteries (DLAs > 30 mm; sensitivity, 0.67; specificity, 0.59; 1 study/66 patients); mean resting tongue thickness (>60 mm; sensitivity, 0.85; specificity, 0.59; 1 study/66 patients); tongue base thickness during Muller maneuver (MM; sensitivity, 0.59; specificity, 0.78; 1 study/66 patients); and a combination of neck circumference and retropalatal (RP) diameter shortening during MM (sensitivity, 1.0; specificity, 0.65; 1 study/104 patients). Nonairway US parameters having a low-moderate correlation with moderate-severe OSA were carotid intimal thickness (pooled correlation coefficient, 0.444; 95% confidence interval [CI], 0.320-0.553; P value = .000, 8 studies/727 patients) and plaque presence (sensitivity, 0.24-0.75; specificity, 0.13-1.0; 4 studies/1183 patients).

CONCLUSIONS

We found that a number of airway and nonairway parameters were identified with moderate to good correlation with OSA diagnosis in the general population. In future studies, it remains to be seen whether PoCUS screening for a combination of these parameters can address the pitfalls of OSA screening questionnaires.

Sonographic Assessment of Oropharynx Movement During Deep Breathing

To investigate the feasibility of ultrasonography in detecting the oropharynx movement during deep breathing and to quantitatively analyze oropharynx airway lumen changes during deep breathing. The motions of oropharynx were monitored, and sonographic measurements of airway lumen were obtained during deep breathing in 448 healthy volunteers. Adequate visualization of oropharynx movement was obtained on all healthy volunteers. The anterior-posterior (AP) diameters and AP/transverse (T) diameter ratios were greater at the end of deep inspiration than that at the end of deep expiration for each sex (p < 0.01). The anterior-posterior dimensional changes were greater than lateral airway dimensional changes each sex (p < 0.05). Ultrasonography could provide realistic impression of the process on the oropharynx movement during deep breathing and perform the quantitative analysis of the oropharynx airway lumen changes during deep breathing. The results were encouraging and supported the utility of ultrasonography in future studies.

Endotracheal Intubation by Paramedics Using Neodymium Magnet and Modified Stylet in Simulated Difficult Airway: A Prospective, Randomized, Crossover Manikin Study

BACKGROUND

The present study evaluates the success and efficacy of endotracheal intubation (ETI) using a modified intubation stylet and a magnet system to direct the stylet into the trachea. The system was developed by the researchers in an attempt to increase the success and efficacy of ETI.

METHODS

ETI procedures were performed on an airway management manikin by emergency medical technicians with at least four years of experience in ETI. The technicians used a stylet modified with an iron ball affixed to the tip and a neodymium magnet, designed specifically for the study. The intention was to guide the endotracheal tube into the trachea at the level of the thyroid and cricoid cartilages on the manikin with the aid of the modified stylet and the magnetic force of the neodymium magnet. The success rate, completion time, and degree of difficulty of two procedures were compared: magnetic endotracheal intubation (METI) and classic ETI (CETI).

RESULTS

The success rate was 100% in both groups. The mean completion times for the METI and CETI procedures were 18.31 ± 2.46 s and 20.01 ± 1.95 s, respectively. There were significant differences in completion time and degree of difficulty between the METI and CETI procedures (both p=0.001).

CONCLUSIONS

We found the use of a neodymium magnet and modified stylet to be an effective method to guide the endotracheal tube into the trachea. The present study may provide a basis for future studies.

Ultrasonographic Evaluation of Upper Airway Structures in Children With Obstructive Sleep Apnea

Importance

Adenotonsillar hypertrophy is an important cause of obstructive sleep apnea (OSA) in children. However, residual OSA and abnormal polysomnographic findings have been reported in up to 75% of cases after adenotonsillectomy. Other anatomical and functional factors that influence upper airway structures, including the lateral pharyngeal wall, have rarely been studied in children with OSA.

Objective

To determine whether the upper airway structures can be evaluated using head and neck ultrasonography and if there is an association between the ultrasonographic measurements for these structures and severity of OSA seen on polysomnography in children.

Design, Setting, and Participants

Prospective, single-center, observational study of 82 children younger than 18 years with a diagnosis of sleep-disordered breathing (20 with primary snoring, 62 with OSA, as determined by the apnea-hypopnea index) and admitted to a tertiary teaching hospital for adenotonsillectomy.

Exposures

Ultrasonography and polysomnography.

Main Outcomes and Measures

Ultrasonographic measurements of upper airway structures.

Results

Of the 82 children studied, 62 (76%) were boys; mean (SD) age, 7.7 (6.2). There was no significant difference found in tonsillar dimensions or volume between the children with OSA and those with primary snoring. However, the mean (SD) total lateral pharyngeal wall and the total neck thicknesses at the retropalatal level were both greater in children with OSA than in those with primary snoring at rest (24.9 [4.4] mm vs 21.3 [2.6] mm; difference, 3.61 mm; 95% CI of difference, 1.48-5.74 mm for lateral pharyngeal wall; and 59.9 [14.4] mm vs 49.9 [11.2] mm; difference, 10.9 mm, 95% CI of difference, 3.8-17.9 mm for the total neck).

Conclusions and Relevance

Estimated tonsillar volume measured using ultrasonography had no relationship with the apnea-hypopnea index in childhood sleep-disordered breathing. However, the lateral pharyngeal wall was significantly thicker in children with OSA than in those with primary snoring at rest.

Ultrasound for diagnosing new difficult laryngoscopy indicator: a prospective, self-controlled, assessor blinded, observational study

BACKGROUND

Unpredictable difficult laryngoscopy (DL) remains a challenge for anesthesiologists, especially when difficult ventilation occurs during standard laryngoscopy. Accurate airway assessment should always be performed, but the common airway assessment methods only perform superficial screening. Thus, the deep laryngopharyngeal anatomy may not be evaluated. Ultrasound-based airway assessment has been recently proposed as a useful, simple, and non-invasive bedside tool as an adjunct to clinical methods, which may facilitate identification of DL. The present study aimed to determine the correlation between ultrasound-measured indicators and DL.

METHODS

Patients undergoing elective surgery under general anesthesia with tracheal intubation were enrolled. Ultrasonic airway assessments were performed before anesthesia induction. Ultrasound diagnostic indicators included the thickness and width of the base of the tongue, the angle between the epiglottis and glottis, the length of the thyrohyoid membrane, and the thickness of the lateral pharyngeal wall. A score of ≥3 in the Modified Cormack-Lehane Scoring System was used as a standard of DL and was also applied to divide patients into DL and non-DL groups. The area under the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic ability of various diagnostic indicators.

RESULTS

A total of 499 patients were enrolled into non-DL and DL groups comprising 452 (452/499, 90.6%) and 47 (47/499, 9.4%) patients, respectively. One ultrasonic diagnoses indicator correlated with DL, namely, the angle between the epiglottis and glottis. When the angle between the epiglottis and glottis was 50°, the area under the ROC curve was maximum (0.902), and the best sensitivity (81%) and specificity (89%) were achieved.

CONCLUSIONS

Airway ultrasounds should be considered to identify DL. The ultrasonic angle measured between the epiglottis and glottis is highly associated with DL, which may occur when the angle is less than 50°.

CLINICAL TRIAL REGISTRATION

ChiCTR-DDT-13004102, http://www.chictr.org.cn/showproj.aspx?proj=5465.

Point of care ultrasound for the clinical anesthesiologist

Diagnostic ultrasonography was first utilized in the 1940s. The past 70+ years have seen an explosion in both ultrasound technology and availability of ultrasound technology to more and more clinicians. As ultrasound technology and availability have grown, the utility of ultrasound technology in the clinical setting as only been limited by clinicians' imagination. Due to its lack of radiation, non-invasive nature, and gentle learning curve, medical ultrasonography is now a tremendously useful Point of Care technology in the clinical arena. What follows is a discussion of Point of Care Ultrasound (PoCUS) and how it can be incorporated in the daily practice of any regional anesthesiology. While most regional anesthesiologists usually focus on the interventional aspects of ultrasonography (i.e. nerve blocks), our discussion will center on the diagnostic value of ultrasonography-especially concerning assessment of cardiac physiology and pathophysiology, gastric anatomy, airway anatomy, and intracranial pathophysiology. After reading and reviewing this chapter, the learner will have the knowledge to start training themselves in a variety of PoCUS exams that will allow rapid diagnosis of normal and abnormal patient conditions. Once an accurate diagnosis is established, the anesthesiologist and his/her team can then confidently optimize an anesthetic pain, prevent harm, and/or treat a patient condition. In this day and age, the ability to rapidly establish an accurate diagnosis cannot be overstated-especially in a critical situation. It is the authors' sincerest hope that the following discussion will help regional anesthesiologist to become even better and well-rounded clinical leaders.

Radiological evaluation of airway - What an anaesthesiologist needs to know!

Airway management forms the foundation of any anaesthetic management. However, unanticipated difficult airway (DA) and its sequelae continue to dread any anaesthesiologist. In spite of development of various clinical parameters to judge DA, no single parameter has proved to be accurate in predicting it. Radiological evaluation may help assess the aspects of patient's airway not visualised through the naked eye. Starting from traditional roentgenogram to ultramodern three-dimensional printing, imaging may assist the anaesthesiologists in predicting DA and formulate plan for its management. Right from predicting DA, it has been used for estimating endotracheal tube sizes, assessing airway pathologies in paediatric patients and planning extubation strategies. This article attempts to provide exhaustive overview on radiological parameters which can be utilised by anaesthesiologists for prediction of DA.

Body Surface Area Is Not a Reliable Predictor of Tracheal Tube Size in Children

Objectives

The age-based Cole formula has been employed for the estimation of endotracheal tube (ETT) size due to its ease of use, but may not appropriately consider growth rates among children. Child growth is assessed by calculating the body surface area (BSA). The association between the outer diameter of an appropriate uncuffed-endotrachealtube (ETT-OD) and the BSA values of patients at 24–96 months of age was our primary outcome.

Methods

Cole formula, BSA, age, height, weight and ultrasound measurement of subglottic-transverse-diameter were evaluated for correlations with correct uncuffed ETT-OD. The Cole formula, BSA, and ultrasound measurements were analyzed for estimation rates in all patients and age subgroups. The maximum allowed error for the estimation of ETT-OD was ≤0.3 mm. Patients’ tracheas were intubated with tubes chosen by Cole formula and correct ETT-OD values were determined using leak test. ETT exchange rates were recorded.

Results

One-hundred twenty-seven patients were analyzed for the determination of estimation rates. Thirteen patients aged ≥72 months were intubated with cuffed ETT-OD of 8.4 mm and were accepted to need uncuffed ETT-OD >8.4 mm in order to be included in estimation rates, but excluded from correlations for size analysis. One-hundred fourteen patients were analyzed for correlations between correct ETT-OD (determined by the leak test) and outcome parameters. Cole formula, ultrasonography, and BSA had similar correct estimation rates. All three parameters had higher underestimation rates as age increased.

Conclusion.

The Cole formula, BSA, and ultrasonography had similar estimation rates in patients aged ≥24 to ≤96 months. BSA had a correct estimation rate of 40.2% and may not be reliable in clinical practice to predict uncuffedETT-size.

Influence of respiratory mechanics and drive on genioglossus movement under ultrasound imaging

METHODS

Twenty healthy subjects (10 males, age 28±5 years [mean ± SD]) lay supine, awake, with the head in a neutral position. Ventilation was monitored with inductance bands. Real-time B-mode ultrasound movies were analysed. We measured genioglossus motion (i) during spontaneous breathing, voluntary targeted breathing (normal tidal volume Vt), and voluntary hyperpnoea (at 1.5Vt and 2 Vt); (ii) during inspiratory flow resistive loading; (iii) with changes in end-expiratory lung volume (EELV).

RESULTS

Average peak inspiratory displacement of the infero-posterior region of genioglossus was 0.89±0.56 mm; 1.02±0.88 mm; 1.27±0.70 mm respectively for voluntary Vt, and during voluntary hyperpnoea at 1.5Vt and 2Vt. A change in genioglossus motion was observed with increased Vt. During increasing inspiratory resistive loading, the genioglossus displaced less anteriorly (p = 0.005) but more inferiorly (p = 0.027). When lung volume was altered, no significant changes in genioglossus movement were observed (p = 0.115).

CONCLUSION

In healthy subjects, we observed non-uniform heterogeneous inspiratory motion within the inferoposterior part of genioglossus during spontaneous quiet breathing with mean peak displacement between 0.5-2 mm, with more displacement in the posterior region than the anterior. This regional heterogeneity disappeared during voluntary targeted breathing. This may be due to different neural drive to genioglossus during voluntary breathing. During inspiratory resistive loading, the observed genioglossus motion may serve to maintain upper airway patency by balancing intraluminal negative pressure with positive pressure generated by upper airway dilatory muscles. In contrast, changes in EELV were not accompanied by major changes in genioglossus motion.

Ultrasound as an Assessment Method in Predicting Difficult Intubation: A Prospective Clinical Study

Objective

Aim of the study is to predict the difficulty in intubation preoperatively using ultrasonography.

Methods

One hundred and thirty-seven patients underwent ultrasound followed by surgery under general anesthesia. A experienced radiologist examined the airway and performed measurements of specific airway parameters: visualization of hyoid bone, visualization of vocal cords through thyroid cartilage, visualization of epiglottis, distance from base of tongue to hyoid bone, distance of hyomental region distance of thyrohyoid region, distance between skin and fat pad thickness to thyroid cartilage, thickness of submental region, distance from epiglottis to skin (above hyoid), and visualization of cricothyroid membrane. After performing ultrasound, patient was presented for surgery. An experienced anesthesiologist who is associated with this study did all the laryngoscopy and intubation.

Results

We were able to visualize all relevant anatomical structures in all the participants using ultrasound. The receiver operating characteristic curve analysis results showed that hyomental is ≤ 1.09 (P value < 0.01) to classify difficult in intubation.

Conclusion

The study shows that ultrasound can reliably image all the airway structures. This study suggests that hyomental distance is a more valid criterion in predicting difficult intubation. Further, case control study is needed for assessing the ease of intubation.

A feasibility study to assess vallecula and pyriform sinus using protocol-based ultrasonic evaluation of floor of mouth and upper airway

PURPOSE

The current study aimed to systematically evaluate the sonoanatomy of floor of the mouth and upper airway using protocol-based ultrasonography (USG); and to assess the feasibility of imaging the valleculae and pyriform fossae.

MATERIALS AND METHODS

An institutional prospective observational study was planned on fifty volunteers of all ages and both sexes, attending outpatient department for nonairway-related diseases. Protocol for ultrasonographic systemic evaluation was designed before starting the trial. All the patients were positioned supine with neck extended (sniffing position), seven steps of ultrasonographic protocol were followed and visualization of structures denoted in each step was documented. Furthermore, time taken to complete each scan was noted.

RESULTS

The USG was completed, and checklist successfully followed in all cases. Floor of mouth structures was easy to evaluate and visualized with ease in all the cases. Epiglottis was visualized in 100% cases in transverse plane. Valleculae and pyriform fossae were identified in 82% and 90% of the cases, respectively, and they appeared either as paired air-filled round structures or air-lined linear structures. Complete visualization of vocal cords was seen in 78% females and 63% males. The average time taken to complete the protocol-based study was 10.4 ± 1.4 min.

CONCLUSIONS

Application of protocol-based USG for upper airway can allow the examination of structures from tongue to thyroid cartilage in a thorough, convenient, and timely manner. The air filled/lined structures such as valleculae, pyriform fossae, and vocal cords can be visualized in majority of the cases.

Sonographic Dynamic Description of the Laryngeal Tract: Definition of Quantitative Measures to Characterize Vocal Fold Motion and Estimation of Their Normal Values

Vocal fold motion was analyzed during free breathing using two-dimensional dynamic ultrasound imaging. Two cadavers were first analyzed to define easily identifiable landmarks. Motion of the laryngeal tract was then analyzed in an axial plane. Left and right arytenoids and thyroid cartilage were defined on images corresponding to abduction and adduction of the laryngeal tract. Associated area measurements were established for 50 healthy subjects. All area indices were significantly larger during abduction than adduction. Symmetry of motion was established by comparing each hemi-larynx, and mobility fractions were defined. Normal values of laryngeal motion during free breathing were thus established.

Ultrasonographic Detection of Airway Obstruction in a Model of Obstructive Sleep Apnea

Purpose Obstructive sleep apnea (OSA) is a common clinical disorder characterized by repetitive airway obstruction during sleep. The gold standard for diagnosis of OSA, polysomnogram (PSG), cannot anatomically localize obstruction. Precise identification of obstruction has potential to improve outcomes following surgery. Current diagnostic modalities that provide this information require anesthesia, involve ionizing radiation or disrupt sleep. To mitigate these problems, we conceived that ultrasound (US) technology may be adapted (i) to detect, quantify and localize airway obstruction and (ii) for translational application to home-based testing for OSA. Materials and Methods Segmental airway collapse was induced in 4 fresh cadavers by application of negative pressure. Following visualization of airway obstruction, a rotary US probe was used to acquire transcervical images of the airway before and after induction of obstruction. These images (n=800) were analyzed offline using image processing algorithms. Results Our results show that the non-obstructed airway consistently demonstrated the presence of a US air-tissue interface. Importantly, automated detection of the air-tissue interface strongly correlated with manual measurements. The algorithm correctly detected an air-tissue interface in 90% of the US images while incorrectly detecting it in 20% (area under the curve=0.91). Conclusion The non-invasive detection of airway obstruction using US represents a major step in expanding OSA diagnostics beyond PSG. The preliminary data obtained from our model could spur further research in non-invasive localization of obstruction. US offers the benefit of precise localization of the site of obstruction, with potential for improving outcomes in surgical management.

Is Ultrasound a Valid and Reliable Imaging Modality for Airway Evaluation?: An Observational Computed Tomographic Validation Study Using Submandibular Scanning of the Mouth and Oropharynx

OBJECTIVES

Ultrasound (US) imaging of the airway may be useful in predicting difficulty of airway management (DAM); but its use is limited by lack of proof of its validity and reliability. We sought to validate US imaging of the airway by comparison to CT-scan, and to assess its inter- and intra-observer reliability. We used submandibular sonographic imaging of the mouth and oropharynx to examine how well the ratio of tongue thickness to oral cavity height correlates with the ratio of tongue volume to oral cavity volume, an established tomographic measure of DAM.

METHODS

A cohort of 34 patients undergoing CT-scan was recruited. Study standardized assessments included CT-measured ratios of tongue volume to oropharyngeal cavity volume; tongue thickness to oral cavity height; and US-measured ratio of tongue thickness to oral cavity height. Two sonographers independently performed US imaging of the airway before and after CT-scan.

RESULTS

Our findings indicate that the US-measured ratio of tongue thickness to oral cavity height highly correlates with the CT-measured ratio of tongue volume to oral cavity volume. US measurements also demonstrated strong inter- and intra-observer reliability.

CONCLUSIONS

This study suggests that US is a valid and reliable tool for imaging the oral and oropharyngeal parts of the airway, as well as for measuring the volumetric relationship between the tongue and oral cavity, and may therefore be a useful predictor of DAM.

Investigation of the Upper Airway Anatomy With Ultrasound

OBJECTIVE

The aims of this study were to describe the relationship between the scanning planes and appearance of the upper airway on sonography and to demonstrate the reliability and reproducibility of sonographic measurements of the upper airway.

METHODS

Airway sonoanatomy was recognized by comparing the airway images and the corresponding cadaver's anatomical specimens. Systemic sonographic examination of 267 healthy volunteers was conducted to obtain the sonographic measurement of airway lumen. The reliability and reproducibility studies were conducted in 40 healthy volunteers.

RESULT

The air-filled upper airway appeared as a bright heterogeneous hyperechoic line. During deep inspiration, the upper airway lumen expanded to the highest anterior-posterior dimension, whereas during deep expiration, the lateral dimension tended to increase. The sonographic measurements had good reproducibility, with intraclass correlation coefficient ranging from 0.722 to 0.887 and 0.727 to 0.882 for interobserver and intraobserver reliability, respectively.

CONCLUSIONS

Ultrasonography can determine the anatomy of the upper airway and perform the quantitative analysis of the upper airway lumen during respiration. The results were encouraging and support the utility of ultrasonography in future airway disorder studies.

Role of upper airway ultrasound in airway management

Upper airway ultrasound is a valuable, non-invasive, simple, and portable point of care ultrasound (POCUS) for evaluation of airway management even in anatomy distorted by pathology or trauma. Ultrasound enables us to identify important sonoanatomy of the upper airway such as thyroid cartilage, epiglottis, cricoid cartilage, cricothyroid membrane, tracheal cartilages, and esophagus. Understanding this applied sonoanatomy facilitates clinician to use ultrasound in assessment of airway anatomy for difficult intubation, ETT and LMA placement and depth, assessment of airway size, ultrasound-guided invasive procedures such as percutaneous needle cricothyroidotomy and tracheostomy, prediction of postextubation stridor and left double-lumen bronchial tube size, and detecting upper airway pathologies. Widespread POCUS awareness, better technological advancements, portability, and availability of ultrasound in most critical areas facilitate upper airway ultrasound to become the potential first-line non-invasive airway assessment tool in the future.

Imaging diagnosis in relapsing polychondritis and correlation with clinical and serological data

OBJECTIVE

We hypothesize that imaging findings from CT and MRI correlate better with clinical markers for assessment of disease activity in patients with the rare relapsing polychondritis (RPC) than with serological inflammatory markers.

MATERIALS AND METHODS

Retrospective database search at our institution identified 28 patients (13 females; age 49.0 years±15.0 SD) with RP between September 2004 and March 2014. Institutional review board approval was obtained for this retrospective data analysis. All patients had clinically proven RPC with at least two episodes of active disease. Of those, 18 patients were examined with CT- and MRI and presented all morphologic features of RPC like bronchial/laryngeal/auricular cartilage thickness, contrast enhancement, increased T2-signal intensity. Imaging data was subsequently correlated with corresponding clinical symptoms like fever, dyspnea, stridor, uveitis, pain, hearing impairment as well as with acute-phase-inflammatory parameters like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

RESULTS

The clinical parameters were in good agreement with imaging findings and clinical symptoms such as tracheal wall thickening and dyspnea (r =0.65 p=0.05), joint synovitis on MRI and a higher McAdam score (r=0.84 p<0.001). No correlations were found between inflammatory laboratory markers, imaging findings and clinical features.

CONCLUSION

Imaging diagnosis in RPC using CT and/or MRI delivers information about the degree of disease activity that correlates better with clinical features than unspecific inflammatory laboratory markers. Additionally, clinically unapparent cartilage involvement can be assessed adding value to the clinical diagnosis and therapy planning in this rare disease.