Confirmation of laryngeal mask airway placement by ultrasound examination: a pilot study

A case of arytenoid dislocation after ProSeal laryngeal mask airway insertion: A case report

INTRODUCTION AND IMPORTANCE

Arytenoid dislocation, typically manifested as hoarseness and coughing when drinking, is a rare perioperative scenario, with an incidence rate of 0.009 %-0.097 % and endotracheal intubation under general anesthesia being the most common cause. However, arytenoid dislocation caused by a laryngeal mask airway (LMA) is extremely rare.

CASE DESCRIPTION

Herein, a 53-year-old female patient was admitted for a "right breast lump" and scheduled for "unilateral mastectomy with ipsilateral axillary sentinel lymph node biopsy" under general anesthesia. During the surgery, the patient was noted to snore mildly, and rocuronium (15 mg) was immediately administered intravenously. The snoring ceased after adjusting the position of the LMA. Postoperatively, the patient was diagnosed with arytenoid dislocation by flexible nasal endoscopy after presenting with a sore throat accompanied by hoarseness and coughing when drinking. Thereafter, the patient underwent two cricoarytenoid joint reductions with a video laryngoscope under intravenous anesthesia, along with anti-inflammatory medication and voice therapy. The voice of the patient returned to normal after 1 month.

CLINICAL DISCUSSION

Despite being a supraglottic airway device, the LMA can still cause arytenoid dislocation in clinical practice. Hence, anesthesiologists should analyze the potential causes and understand the diagnosis and treatment of arytenoid dislocation. Although closed reduction surgery typically requires two or three attempts, with a shorter disease duration leading to better outcomes, it can also aid in voice recovery for a longer disease course. In the presented case, the patient achieved a good prognosis after two closed reduction surgeries.

CONCLUSION

Anesthesiologists should be vigilant for arytenoid dislocation in patients who present with persistent hoarseness and coughing while drinking after the insertion of the LMA, necessitating prompt treatment after diagnoses to achieve the best results.

Flow-Volume Loop: A Tool for Evaluating the Position of the Laryngeal Mask Airway Intraoperatively

The flow-volume loop (FVL) is a valuable yet often underutilized tool for assessing the placement of the laryngeal mask airway (LMA) during surgery. It provides real-time graphical data on airway patency and ventilation. These cases examine the role of FVL in identifying LMA misplacement. Abnormal patterns, such as truncated expiratory curves and reduced peak flows, can indicate partial obstructions that might otherwise go unnoticed. By monitoring FVL, clinicians can quickly detect and correct misalignment, thereby enhancing patient safety and ventilator effectiveness during surgical procedures.

Application of placing the anterior end of endotracheal tube at the glottis in laryngeal mask airway positive ventilation during general anesthesia: A prospective, randomized, controlled trial

BACKGROUND

Glottic contraction and closure causes ventilation obstruction and laryngeal mask airway (LMA) leakage during positive pressure ventilation using LMA. This study aimed to assess the effect of placing the anterior end of the endotracheal tube (ET) at the glottis through the LMA ventilation conduit on treating LMA leakage following glottic contraction and closure.

METHODS

In this prospective, randomized, controlled trial, patients with non-minor surgery using LMA ventilation were randomly allocated to the i-gel group (group L) and the i-gel combined with ET group (group LE). The tip of ET was placed 2 cm under glottis guided by fiberoptic bronchoscope through i-gel ventilation conduit in group LE. The perioperative incidence of i-gel leakage, the changes of systolic blood pressure (SBP) and heart rate (HR) following artificial airway insertion, and adverse events were recorded.

RESULTS

Perioperative i-gel leakage was observed in 7 of 48 patients (14.6%) in group L and 1 of 49 patients (2.0%) in group LE. There was significant difference in the incidence of leakage between the 2 groups (P = .031). SBP and HR after ET insertion in group LE increased significantly compared to those in group L (P < .05/5). The values of both SBP and HR after ET insertion did not exceed the basic values in group LE (P > .05/4). There were no significant differences in the incidence and severity of postoperative sore pain and hoarseness, cough during i-gel and ET removal between the 2 groups (P > .05).

CONCLUSION

Placing the anterior end of ET at the glottis reduced LMA air leakage related to glottic contraction and closure in non-minor surgery. The ET placing had low stress response and did not significantly increase postoperative complications.

Pharyngolaryngeal Morbidity With the Laryngeal Mask Airway SupremeTM at Different Fiberoptic Bronchoscopy Grades: An Observational Study

OBJECTIVE

To assess whether the different fiberoptic bronchoscopy (FOB) grades of laryngeal mask airway (LMA) Supreme™ affects pharyngolaryngeal morbidity (PLM, including sore throat, dysphonia, pharyngoxerosis, and dysphagia) after general anesthesia.

METHODS

A total of 235 adult patients scheduled for elective laser lithotripsy undergoing general anesthesia with the placement of LMA Supreme™ were enrolled. The position of LMA Supreme™ was assessed by FOB and categorized into five grades. Meanwhile, patients were divided into four groups (grades A-D); none was assessed as grade E. We collected blinded data on PLM at 2 (H+2), 6 (H+6), and 24 hours (H+24) postoperatively. The incidence and severity of PLM as the primary outcome and incidence of PLM at three time points as a secondary outcome were compared.

RESULTS

The incidence of PLM was higher at 2 and 6 hours than at 24 hours; however, no significant difference was found between the incidence of PLM in the FOB groups. Furthermore, the severity of sore throat and dysphonia between groups were obviously differed at H+6 and H+24, but similar at H+2. The severity of postoperative pharyngoxerosis and dysphagia were similar between groups at three time points.

CONCLUSIONS

A positive association was found between the severity of postoperative sore throat and dysphonia and FOB grade after LMA Supreme™ placement. PLM secondary to placement of the LMA Supreme™ was short lasting.

Gastric distension and atelectasis after using a supraglottic airway - A case report

BACKGROUND

Supraglottic airways (SGAs) are used during general anesthesia (GA) due to comfort. Certain complications are possible, such as gastric distension. The incidence of pulmonary aspiration of regurgitated gastric contents was found to be 0.02%. A difference in the incidence of gastric regurgitation was not identified between the use of SGAs and endotracheal intubation. We report a case of gastric distension and atelectasis in a patient in whom an I-gel® was used for GA.

CASE

A 63-year-old female patient underwent triple arthrodesis on her ankle under GA using an SGA (I-gel® size 3). After surgery, she suffered from nausea and abdominal bloating. A chest radiograph revealed that a large amount of air in her stomach had caused gastric distention, which resulted in left hemidiaphragm elevation and atelectasis.

CONCLUSIONS

This case illustrates that the use of I-gel® in prolonged surgeries may result in malposition of the SGA and gastric insufflation and atelectasis.

Value of the Hyomental Distance Measured With Ultrasound in Forecasting Difficult Laryngoscopy in Newborns

PURPOSE

Preoperative evaluations of difficult airways are imperative, especially in newborns. The hyomental distance is a reliable index for predicting difficult airways in adults. However, few studies have evaluated the value of the hyomental distance for predicting difficult airways in newborns. It is unclear whether the hyomental distance forecasts a restricted or difficult view when using direct laryngoscopy. We intended to develop an effective system for predicting difficult tracheal intubation in newborns.

DESIGN

A prospective observational clinical study.

METHODS

Newborns aged 0 to 28 days undergoing oral endotracheal intubation with direct laryngoscopy for elective surgery under general anesthesia were enrolled. The hyomental distance and hyoid level tissue thickness were assessed by ultrasound. Other parameters, such as the mandibular length and sternomental distance, were also evaluated before anesthesia. The glottic structure view under laryngoscopy was graded according to the Cormack-Lehane classification. The patients with Grade 1 and 2 laryngeal views were assigned to Group E. Those with Grade 3 and 4 views were assigned to Group D.

FINDINGS

A total of 123 newborns were recruited for our study. The incidence of poor visualization of the larynx during laryngoscopy in our study was 10.6%. The multifactor logistic regression results showed that the hyomental distance was a powerful predictor of difficult laryngoscopy (OR = 0.16, 95% CI 0.03-0.74, P = .019). The curve with the highest sensitivity and specificity and the maximum area under the curve (AUC) was the hyomental distance. The receiver operating characteristic (ROC) curve for the hyomental distance suggested that the best cut-off value was less than equal to 2.74 cm, with an AUC of 0.80 (95% CI 0.64-0.95).

CONCLUSIONS

It is noninvasive and feasible to accurately measure the hyomental distance with ultrasound in newborns, and the results are reliable. We believe that the hyomental distance measured with ultrasound could be used as a marker for predicting difficult laryngoscopy in newborns.

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.

Features of new vision-incorporated third-generation video laryngeal mask airways

Numerous studies have shown that blindly inserted supraglottic airway devices (SADs) are sub-optimally placed in 50 to 80% of all cases. Placement under direct vision has been recommended. We describe the very first two new SADs of the third generation that incorporate a videoscope with flexible tip. Both devices are made up of two interlocking components-the SAD and a videoscope. The 3rd generation, direct vision SADs allow vision-guided insertion, corrective manoeuvres, if needed, and correct placement in the hypopharynx and possess additional features which permit insertion of a gastric tube and endotracheal intubation should the need arise. This article describes the two new devices' physical characteristics, features, rationale for use, advantages and limitations in comparison to existing devices. Each of the two new devices-the Video Laryngeal Mask (VLM^TM, UE Medical®) and the SafeLM® Video Laryngeal Mask System (SafeLM^TM VLMS, Magill Medical Technology®) consist of two parts: (a) a disposable 2nd generation SAD with a silicone cuff and an anatomically curved tube; and (b) a reusable patient-isolated videoscope and monitoring screen, with the flexible scope located into a specially-designed, blind-end channel terminating in the bowl of the SAD, preventing the videoscope from contacting patient body fluids in the SAD bowl. Third generation placement-under-direct-vision supraglottic airway devices possess several theoretical safety and ease of use advantages which now need to be validated in clinical use.

The place of ultrasonography in confirming the position of the laryngeal mask airway in pediatric patients: an observational study

Background and objectives

Laryngeal mask airways are increasingly used as supraglottic devices during general anesthesia. Ultrasonography can provide a dynamic image simultaneous to placing the supraglottic airway device. In the current study, the incidence of suboptimal laryngeal mask airway position and replacement in children was evaluated using simultaneous ultrasonographic imaging.

Methods

A prospective observational study was conducted on 82 patients aged 3–15 years with American Society of Anesthesiologists (ASA) physical status I or II. Patients under general anesthesia and with airway provided by a laryngeal mask airway were included. The position of the laryngeal mask airway was evaluated by ultrasonography on two planes. According to our scoring system, Grade I and Grade II were determined to indicate acceptable placement, while Grade III was determined to indicate unacceptable placement. Suboptimal laryngeal mask airway placement rates and the requirement of replacement were determined. Laryngeal mask airway placement optimized by ultrasonography was evaluated with both leak tests and a fiberoptic laryngoscope.

Results

The average age of the patients was 6.27 ± 4.66 years. After evaluation with ultrasonography, 65 (79.3%) of the laryngeal mask airways were found to be optimally positioned, while the position of 13 (15.9%) had to be corrected, and 4 (4.9%) had to be replaced. There was a moderate positive correlation between the ultrasonographic evaluation and leak test evaluation (p < 0.001; r = 0.628). Relocation of the laryngeal mask airway was determined to be an independent risk factor affecting the development of complications (OR = 2.961; p = 0.046; 95% Cl 2.850–30.745).

Conclusion

The use of ultrasonography to verify and relocate laryngeal mask airway placement is noninvasive and effective.

Utility of ultrasound evaluation of I-Gel® placement in children: An observational study

BACKGROUND

Ultrasound is not widely used to evaluate optimal supraglottic airway positioning even though it could potentially be used to identify and correct problem areas.

AIMS

We evaluated a new ultrasound scoring method to identify the position of the supraglottic airway and detect the location of air leaks during ventilation in pediatric patients.

METHODS

Using a prospective observational study design, we enrolled 90 pediatric patients of ASA physical status I-III scheduled for elective surgery under general anesthesia. After anesthesia induction, patients were assigned to a noncorrection group or a correction group after their first ultrasound evaluation. Noncorrection group comprised patients with tolerable I-Gel positioning based on ultrasound evaluation and no problems with clinical parameters, while the correction group comprised patients with I-Gel mispositioning based on ultrasound.

RESULTS

After the first ultrasound evaluation, 61 patients did not need I-Gel correction (noncorrection group), while 29 patients needed I-Gel correction (correction group) and underwent a second ultrasound evaluation. Airway sealing pressure and total ultrasound score showed a negative correlation (r = -.845, p < .001). The area under the receiver operating curve for total ultrasound score was 0.97 (95% confidence interval, 0.94-0.99; p < .001). In the correction group, ultrasound score and ventilation parameters improved after correction based on ultrasound evaluation.

CONCLUSIONS

Ultrasound scores were negatively correlated with airway sealing pressure in pediatric patients. Ultrasound evaluation is useful for detecting misplacement of the I-Gel and can be a useful tool for correction.

The Role of Lung Ultrasound in the Management of the Critically Ill Neonate-A Narrative Review and Practical Guide

Lung ultrasound makes use of artifacts generated by the ratio of air and fluid in the lung. Recently, an enormous increase of research regarding lung ultrasound emerged, especially in intensive care units. The use of lung ultrasound on the neonatal intensive care unit enables the clinician to gain knowledge about the respiratory condition of the patients, make quick decisions, and reduces exposure to ionizing radiation. In this narrative review, the possibilities of lung ultrasound for the stabilization and resuscitation of the neonate using the ABCDE algorithm will be discussed.

The case for a 3rd generation supraglottic airway device facilitating direct vision placement

Although 1st and 2nd generation supraglottic airway devices (SADs) have many desirable features, they are nevertheless inserted in a similar 'blind' way as their 1st generation predecessors. Clinicians mostly still rely entirely on subjective indirect assessments to estimate correct placement which supposedly ensures a tight seal. Malpositioning and potential airway compromise occurs in more than half of placements. Vision-guided insertion can improve placement. In this article we propose the development of a 3rd generation supraglottic airway device, equipped with cameras and fiberoptic illumination, to visualise insertion of the device, enable immediate manoeuvres to optimise SAD position, verify whether correct 1st and 2nd seals are achieved and check whether size selected is appropriate. We do not provide technical details of such a '3rd generation' device, but rather present a theoretical analysis of its desirable properties, which are essential to overcome the remaining limitations of current 1st and 2nd generation devices. We also recommend that this further milestone improvement, i.e. ability to place the SAD accurately under direct vision, be eligible for the moniker '3rd generation'. Blind insertion of SADs should become the exception and we anticipate, as in other domains such as central venous cannulation and nerve block insertions, vision-guided placement becoming the gold standard.

Ultrasonography for airway management

Ultrasonography (USG) allows a new approach to the airway in anaesthesia and intensive care. USG visualises the airway from the mouth to the lungs. By exploring the entire airway, USG proposes new criteria (1) to assess the risk of difficult laryngoscopy, (2) to anticipate the management of a difficult airway, (3) to confirm the position of the endotracheal tube (ETT), and (4) to confirm that the lungs are effectively ventilated. Intraoperatively, USG may also help to resolve acute ventilatory problems such as pneumothorax, delayed selective bronchial intubation after patient positioning (Trendelenburg, prone or lateral position) or acute pulmonary oedema.

Comparison of leakage test and ultrasound imaging to validate ProSeal supraglottic airway device placement

Background and Aims:

To validate the placement of ProSeal supraglottic airway device using ultrasound (USG) with leakage test in adult population of both sexes.

Material and Methods:

This single-arm observational study was conducted on 80 American Society of Anesthesiology (ASA) I-III patients, undergoing elective surgery under general anesthesia with ProSeal supraglottic airway device. Leakage pressure test was conducted in all cases. The position of the ProSeal laryngeal mask airway (LMA) was assessed by USG in the pharyngeal, laryngeal, and the cranial-caudal axis plane. The fiberoptic examination was done to confirm the position of ProSeal if the seal pressure was <27 cm H₂O, to confirm suboptimal placement. The position of the ProSeal in the three USG planes was allocated a predetermined score. This score was compared with the leakage test to determine the strength of the correlation, sensitivity, and specificity for predicting a need for reinsertion.

Results:

Leakage seal pressure was recorded as <27 cm H₂O in 6 (7.5%) patients and fiberoptic bronchoscopy was done in these cases to determine the need for reinsertion. ProSeal was reinserted in 5 (6.25%) cases. Patients with a composite ultrasound score of 0–1 required ProSeal reinsertion while those with a score of 2–3 did not require reinsertion. Seventy-one patients had seal pressure >27 cm H₂O and a score of 3. USG examination is comparable with leakage test in predicting the requirement of reinsertion (P = 0.003) and a score of 19 equating 0–1 predicted the need for reinsertion with a sensitivity and specificity of 80% and 100%, respectively.

Conclusion:

USG is comparable with the leakage test for confirmation of ProSeal placement.

Comparison of gastric insufflation using LMA-supreme and I-gel versus tracheal intubation in laparoscopic gynecological surgery by ultrasound: a randomized observational trial

Background

The application of bedside ultrasound to evaluate gastric content and volume can assist in determining aspiration risk. Applying positive pressure ventilation via supraglottic airway devices (SAD) can result in a degree of gastric insufflation. This study assessed and compared the antral cross-sectional area (CSA) in patients undergoing laparoscopic gynecological surgery when managed with different SAD.

Methods

One hundred American Society of Anesthesiologists I or II female patients were assessed for inclusion in this study and divided into three groups of different ventilation devices. Patients were randomly allocated into three groups to receive LMA-Supreme (Group S), I-gel (Group I) or tracheal tube (Group T). The primary outcome was the antral cross-sectional area and secondary outcomes included haemodynamic parameters and postoperative morbidity such as sore throat, hoarseness, dry throat, nausea and vomiting.

Results

The antral CSA was not significantly different among three groups before induction (P = 0.451), after induction (P = 0.456) and at the end of surgery (P = 0.195). The haemodynamic variables were significantly higher in the tracheal tube group than in the LMA-Supreme and I-gel groups after insertion (P < 0.0001) and after removal (P < 0.01). Sore throat was detected in none in the I-gel group compare to two patients (6.7%) in the LMA-Supreme group and fifteen patients (50%) in the tracheal tube group. Hoareness was detected in one (3.3%) in the I-gel group compare to two patients (6.7%) in the LMA-Supreme group and eleven patients (36.7%) in the tracheal tube group.

Conclusions

The SADs do not cause obvious gastric insufflation. Thus, LMA-Supreme and I-gel can be widely used as alternative to endotracheal intubation for the short laparoscopic gynecological surgery.

Trial registration

This trial was registered at the Chinese Clinical Trial Registry (ChiCTR1800018212, data of registration, September 2018).

Ultrasound measurement of laryngeal structures in the parasagittal plane for the prediction of difficult laryngoscopies in Chinese adults

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.

Ultrasonographic assessment of airway

Ultrasound is gaining increasing popularity among anesthesiologists as it is readily available and provides real-time imaging for various procedures. It is considered as a "visual stethoscope" of the anesthesiologist. After establishing its use in regional blocks and central venous catheter insertion, it is now finding increasing use in anticipation of difficult airway and securing and maintaining it. It has challenged the classical approach of clinical assessment of airway and allows more dynamic bedside assessment. This article attempts to briefly outline the role of ultrasound and its applications for airway management in patients.

Descriptive study of ultrasound images of the upper airway obtained after insertion of laryngeal mask

OBJECTIVE

To evaluate clinical usefulness of ultrasound images of the upper airway in order to check correct laryngeal mask placement.

MATERIAL AND METHODS

A prospective observational study was conducted on patients scheduled for abdominal surgery under general anaesthesia, in whom the patency of the upper airway was ensured using an Ambu^®AuraGain^TM laryngeal mask. An ultrasound scan was performed of the upper-airway in the cranio-caudal direction and with longitudinal scans in the anterior midline and parasagittal axis, in three moments: before, after inserting and after removing the mask. All recorded images were evaluated in a second time by a radiologist-expert in upper airway ultrasound. Subsequently, the ultrasound data were related to the clinical difficulty of the insertion and presence of air leaks.

RESULTS

Data was collected from 30 patients (20 females and 10 males) being operated on for abdominal hysterectomy (15), eventroplasty (6), uterine myomectomy (3), and umbilical (4) and inguinal herniorrhaphy (2). The blind insertion of the masks did not present difficulties in 24 (80%) patients. Air leakage was detected in 8 (26.7%) patients, which was moderate in 7 cases and severe in one of them. The ultrasound findings confirmed good mask placement in 22 (73.3%) patients. Anatomical airway changes after laryngeal mask extraction were only observed in 3 (12%) patients, all of them minor. There was a statistically significant association (P<.05) between difficulty in inserting the device and the level of air leakage.

CONCLUSIONS

Upper airway ultrasound is a useful diagnostic method to evaluate laryngeal mask placement. Laryngeal oedema was not observed after removal of the device.