Air Column Width Research Articles

The usefulness of ultrasonographic measurement of the laryngeal air column width difference before extubation as a predictor of secondary airway obstruction after extubation in children

Background: Postextubation airway obstruction, also called postextubation stridor, is one of the most frequent complications of orotracheal intubation and the main cause of extubation failure (EF). Several potential predictors of extubation outcomes have been investigated, although their predictive value and clinical usefulness are limited. Laryngeal ultrasound and measurements are new, noninvasive, easily reproducible methods for extubation success. The objective of the study was to determine the usefulness of measuring the laryngeal air column width difference (LACWD) as a predictor of EF. Subjects and Methods: This prospective observational study was conducted from December 2022 to March 2023. Patients older than 30 days and up to 16 years of age admitted to the pediatric intensive care unit (PICU) and intubated with an endotracheal tube with a balloon for >24 h and with their first attempt at extubation were evaluated. The LACWD was measured before extubation. The first measurement was made with the balloon inflated and the second with the balloon deflated, calculating the difference between the two measurements. Results: Forty-five patients were assessed. The median number of days in the PICU was 8 (interquartile range 2–6). We found that the greater the difference in the air column, the lower the risk of EF ([P = 0.418] odds ratio [OR] =0.101 95% confidence interval [CI] =0.000–26.000), and the greater the number of days (>3), the greater the risk of EF ([P = 0.819] OR = 0.996; 85% CI = 0.965–1.028). Conclusions: No statistically significant relationship was found in the LACWD in our patients. We believe that it is important to carry out an extended study, with age group stratification, to assess its use.

Preventing Laryngeal Edema Using Single Dose Methylprednisolone in Critically Ill Patients

Background: Post extubation stridor (PES) is a common concern in mechanically ventilated patients, and various therapies have been explored to prevent its occurrence. This study aimed to compare the effectiveness of a single dose of corticosteroid with a placebo in patients at high risk for PES, as determined by cuff leak volume and laryngeal air column width difference (LACWD). Methodology: A randomized clinical trial was conducted in a tertiary care hospital, involving 222 patients aged >18 years of both genders who had been on mechanical ventilation for more than 24 hours and were planned for extubation. Group A (intervention) received methylprednisolone sodium succinate at a dose of 40 mg in 2 ml normal saline, while Group B (placebo) received 2 ml normal saline. Patients were divided into two groups based on cuff leak percentage and LACWD: a low-risk group (Group 1) with cuff leak > 24% and/or LACWD > 0.9 mm, and a high-risk group (Group 2) with cuff leak < 24% and/or LACWD < 0.9 mm. Results: Post extubation stridor occurred in 2 (2.7%) patients in Group 1 (low-risk group) and in 34 (23.0%) patients in Group 2 (high-risk group) (p=0.00). In Group 2, PES was observed in 9 (12.2%) patients who received methylprednisolone (Group A) and in 25 (33.8%) patients who received the placebo (Group B) (p=0.00). Reintubation was required in 1 (1.4%) patient in Group 1 and in 18 (12.2%) patients in Group 2 (p=0.00). Among Group 2 patients, reintubation was needed in 5 (5.24%) patients in Group A and 14 (18.9%) patients in Group B (p=0.01). Patients who developed PES had significantly lower mean cuff leak and mean LACWD compared to those who did not develop PES (19.6% vs 22.6%; p=0.00 and 0.79 mm vs 0.85 mm; p=0.004, respectively). Notably, PES was observed more frequently in females. Conclusions: Treatment with methylprednisolone significantly reduced the incidence of PES and the need for reintubation in high-risk patients compared to the placebo group. Patients who developed PES had lower cuff leak and LACWD values, and a higher proportion of females experienced PES.

Laryngeal Ultrasonography and Percent Leak Volume in Predicting Post-Extubation Stridor in The Pediatric Intensive Care Unit Patients

Background: Endotracheal tube intubation can be associated with laryngeal edema, which may present as post-extubation stridor (PES). PES may prolong length of stay in pediatric intensive care unit, particularly if reintubation was necessary. Objective: To evaluate the efficacy of laryngeal ultrasonography and percent leak volume (PLV) in predicting PES in pediatric patients. Materials and Methods: A prospective study of 43 pediatric patients admitted to pediatric intensive care unit was conducted. Laryngeal ultrasonography was performed to measure air column width (ACW) within 24 hours after intubation. Within four hours before extubation, laryngeal ultrasonography was repeated. Air column width ratio (ACWR) was calculated by ACW before extubation divided by ACW after intubation. PLV was calculated by the difference between inspiratory and expiratory tidal volume divided by inspiratory tidal volume. Both of ACWR and PLV were analyzed to determine the optimal cut-off value for predicting PES. Results: Twenty-two patients (51%), developed PES. Receiver operating characteristics curve (ROC) analysis showed that ACWR at cut-off point ≤0.94 had a sensitivity of 72.7%, specificity of 61.9%, positive predictive value (PPV) of 66.7%, and accuracy of 67.4% in predicting PES. A cut-off point of PLV of less than 9.74% had 59.1% sensitivity, 57.1% specificity, 59.1% PPV, and 58.1% accuracy in predicting PES. ACWR and PLV had an area under the ROC curve (AUC) of 0.722 (p=0.013, 95% CI 0.56 to 0.87) and 0.602 (p=0.253, 95% CI 0.43 to 0.77), respectively. Conclusion: ACWR measured by laryngeal ultrasonography of 0.94 or less may be helpful in predicting PES. ACWR is more accurate than PLV in predicting PES. Keywords: Laryngeal ultrasonography; Percent leak volume; Post-extubation stridor

Abstract No.: ABS2336: Ultra-sound-guided laryngeal air column width ratio as a predictor of post-extubation stridor in paediatric trauma patients: A prospective, observational study.

Background and Aims:Paediatric trauma patients need prolonged ventilation leading to post-extubation laryngeal oedema and stridor. Air-column width change reflects air leak and airflow around the endotracheal tube and vocal cords. Laryngeal air column width difference and ratio (LACWD and LACWR) are non-invasive methods for predicting the post-extubation stridor (PES).Methods:All children aged 1–14 years admitted to the trauma intensive care unit (TICU) for mechanical ventilation for >24 hours were included over 1 year. For intubated patients, if the size of the endotracheal tube was too large or too small, it was appropriate, whereas with an inappropriate size, the tube was changed. Cuff pressures were monitored and kept at or <20 cm of H2O. Dexamethasone was administered at 0.3 mg/kg/8 hours for 48 hours prior to planned extubation. LACW was measured on the day of receiving in TICU, immediately following intubation, prior to steroid therapy and before extubation. The Cuff leak test was used prior to the start of steroid therapy and before extubation.Results:A total of 50 patients were included, out of which 11 (22%) patients developed PES. Of the total number of patients, seven were intubated in TICU, whereas 43 patients were received intubation from outside. The positive predictive value cut-off of ultra-sound-guided LACWR to diagnose PES was <0.93 with a sensitivity of 90.91 and a specificity of 84.62.Conclusion:Ultra-sound-guided LACWD and LACWR are non-invasive methods of predicting PES in paediatric trauma patients.

Laryngeal air column width ratio in predicting postextubation stridor

Abstract Background Cuff leak test (CLT) has been used widely to assess upper airway patency before extubation but with low positive predictive value. Aim To assess the diagnostic accuracy of the airway column width ratio (ACWR) in predicting postextubation stridor (PES). Patients and methods 50 Patients who intubated &amp;gt;24 hours were observed for postextubation stridor and reintubation. Laryngeal ultrasound was done to measure the ACW with ETT cuff deflated immediately after intubation and 3–4 h before extubation. Cuff leak test was done. Results Fifty patients were included with mean age 58 ± 14.71 years, 68% were males and 32% were females. PES developed in 8% of patients. There was highly statistically significant difference between both groups regarding ACW before extubation and ACW ratio (p-value =0.006 and 0.000 respectively). The mean ACW ratio in stridor group (0.79 ± 0.03) was significantly lower than in non-stridor group (0.94 ± 0.04). Reintubation was higher in stridor group (100%) than non-stridor group (23.9%), P = 0.001. There was statistically significant higher duration of mechanical ventilation in stridor group (7.50 ± 0.58 vs. 4.23 ± 2.50 days, P = 0.013). A cut off point of ACW ratio ≤0.81 has a sensitivity 100% and Specificity 100%. Conclusion ACW showed excellent utility in prediction of patients with PES. Air column width ratio of ≤ 0.81 was a good predictor of PES.

Comparison of Laryngeal Ultrasound and Cuff Leak Test to Predict Post-Extubation Stridor in Total Thyroidectomy.

Prediction of post-extubation stridor (PES) after thyroid surgeries has been challenging, and many criteria such as preoperative clinical parameters and intraoperative cuff leak test (CLT) have been used with variable results. The application of laryngeal ultrasound in predicting PES is a relatively new and non-invasive technique. Measurement of the air column width difference (ACWD) by laryngeal ultrasonography can predict PES. This study aimed to evaluate the efficacy of laryngeal ultrasound in the prediction of PES in patients after thyroidectomy and compare it with that of the CLT. A total of 200 patients who had undergone total thyroidectomy under general anaesthesia in a tertiary healthcare hospital were enrolled in the study. At the end of the surgery, air column widths (ACWs) were measured during endotracheal cuff inflation and deflation using laryngeal ultrasound in patients with spontaneous breathing. ACWD was measured and compared with that of the CLT at the time of extubation to predict PES. A total of 12 (6%) patients developed PES. ACWD using laryngeal ultrasound and CLT showed high sensitivity (91.7% and 92.6%, respectively), specificity (91.7% and 90.4%, respectively) and negative predictive value (99.43% and 99.42%, respectively) with low positive predictive value (44% and 37.93%, respectively) for both the diagnostic tests. Application of laryngeal ultrasound in combination with CLT can help the anaesthesiologist in decision making with the extubation plan after thyroid surgeries.

OPTIMAL CUTOFF VALUES IN IMPROVING ACCURACY OF CUFF LEAK TEST AND LARYNGEAL ULTRASONOGRAPHY IN PREDICTING POST EXTUBATION CLINICALLY SIGNIFICANT LARYNGEAL EDEMA IN CRITICAL CARE PATIENTS IN LUNG CENTER OF THE PHILIPPINES

SESSION TITLE: Respiratory Care Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: Inherent risk of endotracheal tube extubation is laryngeal edema. If clinically significant, it may lead to extubation failure, reintubation, and subsequent multitude of other complications. Laryngeal edema being a consequence of extubation, a predictive diagnostic test utilization is critically important. Non-invasive test such as cuff leak test (CLT) and laryngeal ultrasonography (LUS) have been employed. In this study, we aimed to determine the cutoff value of CLT and LUS in predicting clinically significant laryngeal edema applicable in intubated critical care patients of Lung Center of the Philippines. METHODS: A total of 80 mechanically ventilated adult patients in critical care units, wards, and recovery room, evaluated ready for extubation were tested using CLT and LUS prior to endotracheal tube liberation. Patients were observed within 24 hours for post extubation stridor, wheezing, desaturations, and respiratory distress as clinical significant symptoms of laryngeal edema. RESULTS: Of the 80 intubated patients evaluated, clinically significant laryngeal edema was present in 12.5% of patients. Of the 10 patients noted with clinically significant laryngeal edema 3.8% were observed to developed post extubation stridor. Accuracy of the cuff leak test and the laryngeal ultrasound was 96.1% and 86.2%, respectively. The optimal cutoff value for cuff leak volume was 13% with sensitivity and specificity of 100% and 91.4%, respectively. The optimal cutoff value for air column width difference was 33 mm with sensitivity and specificity were 100% and 70%, respectively. Negative predictive value were 100% for both test. Positive predictive values for CLT and LUS were 62.5% and 32.%, respectively. CONCLUSIONS: Both CLT and LUS showed high accuracy rate in predicting post extubation clinically significant laryngeal edema, being CLT higher than LUS. Both test showed high sensitivity, specificity, and negative predictive value. However, positive predictive values for both test were significantly low. CLINICAL IMPLICATIONS: Use of cuff leak test and laryngeal ultrasound may be integrated as part of institutional extubation protocol. DISCLOSURES: no disclosure on file for Maria Charisma Laborte; No relevant relationships by Portia Maria Tanyag, source=Web Response

The Role of laryngeal ultrasound in comparison with cuff leak test in prediction of post extubation stridor

Abstract Background Endotracheal intubation is commonly used in (ICU) for different causes. However, intubation/extubation may lead to the development of complications such as post-extubation stridor (PES), one of the most frequent causes of reintubation, prolonged mechanical ventilation, and increased morbidity in the ICU patients. PES and upper-airway obstruction are multifactorial in etiology and can occur as a result of laryngotracheal edema, intubation trauma, excessive cuff pressure with mucosal ulceration, and prolonged intubation with secondary inflammation and granuloma formation. Objective: The aim of this study was to evaluate the value of laryngeal ultrasonography versus cuff leak test in predicting post-extubation stridor. Patients and Methods Our study included fifty patients admitted to the critical care department, Misr University for Science and Technology Hospitals from the period of November 2017 to July 2018 intubated for different causes for a minimum of 24 h. excluded patients primarily intubated for the upper airway obstruction, patients with laryngeal carcinoma, Previous tracheostomy, neck radiotherapy. All patients will undergo for laryngeal ultrasonography versus cuff leak test to predict post-extubation stridor. Results In our study CLT identified PES patients with a sensitivity of 75%. But with low PPV of 50% for leakage volume of (132.5 mm ) . Laryngeal ultrasound showed a sensitivity of 50% for those patients with air column width before deflation less than 10.955 mm and ACWD 0.905 mm with PPV of 11.8% and 14.3% for air column width and ACWD respectively Conclusion Both CLT (Cuff leak test) and laryngeal US (ultrasound) might have sensitivity in predicting PES and should be used with caution in this regard.

Laryngeal ultrasound as a bedside tool in detecting postextubation stridor in patients with respiratory illness

Context Postextubation stridor is a serious complication in respiratory ICU. Laryngeal ultrasound (US) could be helpful in its diagnosis. Aim The aim was to evaluate accuracy of laryngeal US in detecting postextubation stridor in patients with respiratory illness. Patients and methods A prospective observational study was conducted. A total of 167 mechanically ventilated patients were consequently included over a 2-year period. Laryngeal US air column width (ACW) was measured just after intubation and at the time of extubation. Air column width ratio (ACWR) (ACW before extubation/ACW after intubation) and air column width difference (ACWD) at the time of extubation (ACW with cuff deflated-ACW with cuff inflated) were calculated. Statistical analysis Statistical Package for the Social Sciences statistical software computer program version 20 and Medcalc v. 11.6 were used. Nonparametric tests were used. Results Among the included patients, 17 (10.2%) patients developed stridor. Both ACWR and ACED were significantly lower in patients with stridor than those without stridor (0.798 ± 0.051 vs 0.893 ± 0.056,P Conclusions US is a valuable tool in detecting postextubation stridor. US -guided ACWR and ACWD could be accurate methods for predicting postextubation stridor in RICU.

Predictive value of cuff leak test, laryngeal ultrasound, and fiberoptic laryngoscopy for postextubation stridor after prolonged intubation

Background Endotracheal intubation is frequently complicated by laryngeal edema, which may present as postextubation stridor (PES) or respiratory difficulty or both. Multiple tests were used to predict the PES. The present study aimed at description and evaluation of the predictive values of the cuff leak test (CLT), laryngeal ultrasound (LUS), and indirect flexible fiberoptic laryngoscopy (FOL) to predict PES in ICU patients after prolonged intubation. Patients and methods This prospective study was conducted on 60 intubated patients who were admitted into the surgical intensive care unit. After successful 30-min spontaneous breathing trial and within 6 h before the planned extubation, CLT, LUS, and FOL were performed for all patients. After extubation, the patients were observed and classified into two groups according to the presence of PES within 48 h. Results Two patients were excluded owing to self-extubation, and 58 patient’s data were analyzed. There was no significant difference in CLT volume and the leak fraction between the patients with PES (PES group) and those without PES (non-PES group). However, statistically, air column width with balloon inflated or deflated was significantly lesser in the PES group than the corresponding values in the non-PES group (P=0.04 and 0.009, respectively). Moreover, there was a high significant difference in the air column width difference between both groups (P Conclusion For the noninvasive methods, the CLT has a low predictive value with high possibility of false results, but the data from LUS can be used for approximate evaluation of the laryngeal lumen narrowing; however, the interpretations of the ultrasound data are not conclusive. On the contrary, the FOL is the best accurate diagnostic tool but it is invasive.

The role of laryngeal ultrasound in predicting postextubation laryngeal edema

Purpose The purpose of this study is to determine the accuracy of portable bedside ultrasound (US) in the ICU in predicting postextubation stridor (PES). Patients and methods This prospective observational cohort study enrolled 80 patients who were admitted to Alexandria Main University Hospital, who were planned for extubation. The air-column width difference (ACWD) was measured before planned extubation using a portable US. The primary goal was to assess the diagnostic accuracy of ACWD to predict the presence of significant laryngeal edema (LE), enough to cause PES. Bronchoscopy was done to confirm the presence of PES, whenever possible. Results The prevalence of LE was 25%. The data collected from patients, with and without PES showed no definite risk factors for PES. A cutoff point of 0.9 mm change in ACWD (ACWD at vocal cords) was identified (P Conclusion Portable ICU US measuring ACWD between predeflation and postdeflation of endotracheal tube cuff balloon is a tool of a very good prospective in predicting PES.

Ultrasound-Guided Laryngeal Air Column Width Difference as a New Predictor for Postextubation Stridor in Children

To assess the efficacy of ultrasound-guided laryngeal air column width difference in predicting postextubation stridor in children. Prospective observational study. Single, tertiary care pediatric hospital. This study was carried out at PICU and surgical ICU, Tanta University Hospital on 400 ventilated children between January 2015 and May 2017. Patients who received mechanical ventilation and met criteria for a weaning trial were included. Laryngeal ultrasound and cuff leak test. Ultrasound-guided laryngeal air column width and cuff leak test were measured before extubation. Laryngeal air column width is the width of air between the vocal cords seen by laryngeal ultrasonography. Laryngeal air column width difference is the width difference of air column passed through vocal cords with the balloon cuff inflated and deflated. Three-hundred fifty six patients (89%) had no postextubation stridor, whereas 44 patients (11%) developed postextubation stridor. Postextubation stridor was associated with younger age, less weight, female gender, prolonged duration of intubation, and ICU stay (p < 0.05). Both laryngeal air column width difference and cuff leak test showed significant decrease (p < 0.05) in patients with postextubation stridor in comparison with no postextubation stridor patients. Receiver operating characteristics curve analysis showed that laryngeal air column width difference at cutoff point of less than 0.8 mm gave a sensitivity of 93%, specificity of 86%, and accuracy of 91%, whereas cuff leak test at less than 11% yielded a sensitivity of (61%), specificity of (53%), and accuracy of (59%) for predicting postextubation stridor. Laryngeal air column width difference measurement may serve as a simple reliable noninvasive method for predicting postextubation stridor in children.

Laryngeal ultrasound versus cuff leak test in prediction of post-extubation stridor

BackgroundCuff leak test (CLT) has been proposed as a simple method of predicting post-extubation stridor (PES), however due to different cut-off point of cuff-leak volume between previous studies, the laryngeal ultrasonography (US) including measurement of air column width was used to predict PES. The aim of the present study was to evaluate the value of laryngeal US versus cuff leak test in predicting PES. MethodsThe study included fifty patients admitted to the Critical Care Department, Cairo University Hospitals from the period of November 2014 to January 2016, intubated for at least 24 h and examined prior to extubation using CLT and laryngeal ultrasound. ResultsFour cases developed PES. CLT identified PES patients with a sensitivity of 75%, with PPV of 50% for leakage volume of 132.5 ml. Laryngeal ultrasound showed a sensitivity of 50% for those patients with air column width before deflation less than 10.955 mm and air column width difference (ACWD) of 0.905 mm with PPV of 11.8% and 14.3% for both respectively. ConclusionBoth CLT and laryngeal US might have low sensitivity and PPV in predicting PES and should be used with caution in prediction of PES.

Ultrasound-guided laryngeal air column width difference and the cuff leak volume in predicting the effectiveness of steroid therapy on postextubation stridor in adult. Are they useful?

ObjectiveTo evaluate the effectiveness of steroids therapy on postextubation stridor (PES) depending on the clinical response, the ultrasound guided laryngeal air column width difference (LACWD) and the cuff leak volume (CLV). DesignProspective, observer-blinded study. SettingCarried out in intensive care unit in Tanta university hospital. Patients432 patients of both sexes received mechanical ventilation for more than 24 hours and met defined criteria for a weaning trial. MeasurementsUltrasound guided LACWD and CLV were conducted before extubation. Patients developing postextubation stridor were intravenously given 8 mg of dexamethasone every 8 hours for 3 days. The clinical response, ultrasounds guided LACWD and CLV before and after steroid therapy were analyzed. Primary outcome and secondary outcomes of our study were reported. Results387 patients (89.5%) had no PES and 45 patients (10.5%) had PES. Risk factors for PES were longer duration of intubation, younger age and female gender. Both CLV and LACWD showed significant decrease (P< .05) in patients with PES in comparison with no PES patients. 45 patients with PES received dexamethasone treatment; 18 were completely recovered while 27 patients needed reintubation after 1 h. of these 27 patients; 19 patients had successful extubation while 8 patients had tracheostomy. In patients with PES, CLV and LACWD showed significant increase (P< .05) in comparison with before administration. Level of CLV <200 ml and LACWD <0.9 mm carry high sensitivity with high positive predictive value and high accuracy for presence of PES. ConclusionSteroids therapy improves postextubation stridor. Both LACWD and CLV are non-invasive and simple methods for monitoring of laryngeal edema regression after steroid therapy. We recommend administration of corticosteroids to patients with a lower level of leak volume and LACWD before extubation.

Laryngeal air column width ratio in predicting post extubation stridor.

Aim:Correlation of upper air column width ratio in postextubation stridor patients.Materials and Methods:A prospective observational study was conducted in a tertiary hospital between January and December 2013. Patients who were admitted in Intensive Care Unit and intubated for >24 h were included (72 patients). The upper airway air column width ratio (air column width before extubation/air column width after intubation) was calculated and compared in patient with or without postextubation stridor.Results:The incidence of stridor was 6.9% (5/72). The duration of mechanical ventilation was 5.60 ± 1.14 days and 3.91 ± 1.45 days in stridor and nonstridor group respectively. In all 5 patients who had stridor, the upper airway air column width ratio was 0.8 or less.Conclusion:Air column width ratio of 0.8 or less may be helpful in predicting postextubation stridor, which should be confirmed by large observational studies.

Cuff leak test and laryngeal survey for predicting post-extubation stridor.

Background and Aims:Evidence for the predictive value of the cuff leak test (CLT) for post-extubation stridor (PES) is conflicting. We evaluated the association and accuracy of CLT alone or combined with other laryngeal parameters with PES.Methods:Fifty-one mechanically ventilated adult patients in a medical-surgical intensive care unit were tested prior to extubation using; CLT, laryngeal ultrasound and indirect laryngoscopy. Biometric, laryngeal and endotracheal tube (ETT) parameters were recorded.Results:PES incidence was 4%. CLT demonstrated ‘no leak’ in 20% of patients. Laryngeal oedema was present in 10% of the patients on indirect laryngoscopy, and 71% of the patients had a Grades 1-3 indirect laryngoscopic view. Mean air column width on laryngeal ultrasound was 0.66 ± 0.15 cm (cuff deflated), mean ratio of ETT to laryngeal diameter was 0.48 ± 0.07, and the calculated CLT and laryngeal survey composite was 0.86 ± 1.25 (range 0-5). CLT and the CLT and Laryngeal survey composite measure were not associated with or predict PES. Age, sex, peri-extubation steroid use, intubation duration and body mass index were not associated with PES.Conclusion:Even including ultrasonographic and indirect laryngoscopic examination of the airway, no single aspect of the CLT or combination with laryngeal parameters accurately predicts PES.

Laryngeal ultrasonography versus cuff leak test in predicting postextubation stridor.

Introduction: Although cuff leak test has been proposed as a simple method of predicting the occurrence of postextubation stridor, cut-off point of cuff-leak volume substantially differs between previous studies. In addition, laryngeal ultrasonography including measurement of air column width could predict postextubation stridor. The aim of the present study was to evaluate the value of laryngeal ultrasonography versus cuff leak test in predicting postextubation stridor. Methods: In a prospective study, all patients intubated for a minimum of 24 h for acute respiratory failure, airway protection and other causes were included. Patients were evaluated for postextubation stridor and need for reintubation after extubation. The cuff leak volume was defined as a difference between expiratory tidal volumes with the cuff inflated and deflated. Laryngeal air column width was defined as the width of air passed through the vocal cords as determined by laryngeal ultrasonography. The air-column width difference was the width difference between balloon-cuff inflation and deflation. Results: Forty one intubated patients with the mean age of 57.16±20.07 years were included. Postextubation stridor was observed in 4 patients (9.75%). Cuff leak test (cut off point: 249 mL) showed sensitivity and specificity of 75% and 59%, respectively. In addition, laryngeal ultrasonography (cut off point for air column width: 10.95 mm) resulted in sensitivity and specificity of 50% and 54%, respectively. Positive predictive value of both methods were <20%. Conclusion: Both cuff leak test and laryngeal ultrasonography have low positive predictive value and sensitivity in predicting postextubation stridor and should be used with caution in this regard.

Predicting laryngeal edema in intubated patients by portable intensive care unit ultrasound

PurposeThe purpose of this study is to determine the diagnostic accuracy of portable ultrasound for detection of laryngeal edema (LE) in intubated patients. Materials and MethodsWe conducted a prospective, observational study from December 2010 to September 2011. We measured air column width differences (ACWD) in planned extubation patients admitted in intensive care unit by ultrasound. The primary outcome was the diagnostic accuracy of ACWD to predict the presence of LE. ResultsA total of 101 patients were enrolled. The prevalence of LE was 16.8%. Baseline characteristics were similar between intubated patients with and without LE. The mean difference of increasing of air column width in patients without LE was higher than in LE group (1.9 vs 1.08 mm, P < .001). The sensitivity and specificity at ACWD higher or equal to 1.6 mm were 0.706 and 0.702, respectively. The positive predictive value and negative predictive value were 0.324 and 0.922, respectively. The area under the receiver operating characteristic curve of laryngeal ultrasound was 0.823 (95% confidence interval, 0.698-0.947) and that of cuff leak test was 0.840 (95% confidence interval, 0.715-0.964). ConclusionPortable intensive care unit ultrasound visualizing ACWD between predeflation and postdeflation cuff balloon is a promising objective tool, which aids in prediction of successful extubation regarding LE.

Laryngeal ultrasound: a useful method in predicting post-extubation stridor. A pilot study

The cuff-leak test was widely used for the prediction of post-extubation stridor, but controversial results limit its clinical application. The current study used real-time ultrasonography to evaluate the air-leak and hypothesised that the air-column width, measured by ultrasonography, may be correlated to the development of post-extubation stridor. From June 1, 2001 to March 1, 2002, a total of 51 planned extubations in 51 consecutively intubated patients were included. All of the patients received ultrasonographical examinations of their vocal cords and larynx in addition to an air-column width measurement within 24 h prior to extubation. The overall post-extubation stridor rate was 7.8%. The air-leak volume presented as median (interquartile range) were 300 (350) mL and 25 (20) mL, respectively, for the nonstridor and stridor groups. The air-column width during cuff deflation was 6.4 (2) mm and 4.5 (0.8) mm, respectively. They were found to be statistically significant. In conclusion, the authors demonstrated that laryngeal ultrasonography could be a reliable, noninvasive method, in the evaluation of vocal cords, laryngeal morphology and the ease of airflow, which passed through vocal cords or subglottic area due to laryngeal oedema. The air-column width during cuff deflation was a potential predictor of post-extubation stridor.