Lung sonography can improve the specificity of determination of left-sided double-lumen tracheal tube position in both novices and experts: a randomised prospective study

Pleural lung sliding quantification using a speckle tracking technology: A feasibility study on 30 healthy volunteers

INTRODUCTION

Speckle tracking technology quantifies lung sliding and detects lung sliding abolition in case of pneumothorax on selected ultrasound loops through the analysis of acoustic markers.

OBJECTIVES

We aimed to test the ability of speckle tracking technology to quantify lung sliding using a pleural strain value (PS).

METHODS

We performed a prospective study in 30 healthy volunteers in whom we assessed the pleural speckle tracking using ultrasound loops. Seven breathing conditions with and without non-invasive ventilation were tested. Two observers analyzed the ultrasound loops in four lung areas (anterior and posterior, left and right) and compared the obtained PS values. The first endpoint was to determine the feasibility of the PS measurement in different breathing conditions. The secondary endpoints were to assess the intra- and inter-observer's reliability of the measurement to compare PS values between anterior and posterior lung areas and to explore their correlations with the measured tidal volume.

RESULTS

We analyzed 1624 ultrasound loops from 29 patients after one volunteer's exclusion. Feasibility of this method was rated at 90.8 [95%CI: 89.6 - 92.4]%. The intra-observer reliability measured through Intraclass Correlation Coefficients was 0.96 [95%CI: 0.91-0.98] and 0.93 [95%CI: 0.86-0.97] depending on the operator. The inter-observer reliability was 0.89 [95%CI: 0.78-0.95]. The PS values were significantly lower in the anterior lung areas compared with the posterior areas in all breathing conditions. A weak positive correlation was found in all the lung areas when a positive end expiratory pressure was applied with r = 0.26 [95%CI: 0.12;0.39]; p < 0.01.

CONCLUSION

Speckle tracking lung sliding quantification with PS was applicable in most conditions with an excellent intra- and inter-observer reliability. More studies in patients under invasive mechanical ventilation are needed to explore the correlation between PS values of pleural sliding and tidal volumes.

CLINICAL REGISTRATION

NCT05415605.

Preoperative lung ultrasound for confirming the double-lumen endotracheal tube position for one-lung ventilation: A systematic review and meta-analysis

Objectives

Insertion of a double-lumen endotracheal tube (DLT) is the most commonly used method for one-lung ventilation (OLV). This meta-analysis was aimed at investigating the performance of lung ultrasound in assessing the DLT position in OLV.

Methods

Electronic databases were searched for related trials from inception to October 2022. The primary outcome was the performance of ultrasound or clinical evaluation in confirming the correctness of the DLT position, using fiberoptic bronchoscopy or intraoperative direct visualization of lung collapse as the gold standard. The secondary outcome was the time required to confirm or adjust the DTL position.

Results

Five randomized controlled trials and three observational studies involving 771 patients were included in the meta-analysis. The pooled sensitivity and specificity of ultrasound were 0.93 (95% confidence interval [CI]: 0.79-0.98) and 0.61 (95% CI: 0.41-0.77), respectively, while those of clinical evaluation were 0.93 (95% CI: 0.73-0.99) and 0.35 (95% CI: 0.25-0.47), respectively. The pooled procedure duration was 122.27 s (95% CI: 20.85-223.69) with ultrasound and 112.03 s (95% CI: 95.30-128.76) with clinical evaluation. The area under the curve for discriminating the DLT position was 0.86 (95% CI: 0.82-0.88) for ultrasound and 0.52 (95% CI: 0.48-0.57) for clinical evaluation.

Conclusions

Compared to clinical evaluation, ultrasound has a similar sensitivity but a better specificity for confirming the correctness of the DLT position. Ultrasound is an acceptable imaging tool for assessing DTL placement in OLV.

Role of Lung Ultrasound in Confirmation of Double Lumen Endotracheal Tube Placement for Thoracic Surgeries: A Prospective Diagnostic Accuracy Study

Background

In thoracic surgeries requiring thoracotomy incisions, correct positioning of the double-lumen endotracheal tube (DLT) is mandatory. After the pandemic of novel COVID-19, using simple, noninvasive technology such as lung ultrasound (LUS) can be important in avoiding the possibility of spreading infectious diseases or contagious infections that can follow using fiberoptic bronchoscopy (FOB).

Objectives

We aimed to assess the accuracy of auscultation and LUS in relation to FOB in the assessment of DLT placement and to identify the possibility of using LUS as an alternative to FOB during DLT insertion.

Methods

This diagnostic accuracy study was conducted according to STARD guidelines; enrolled 120 cases requiring DLT intubation. After DLT insertion, all patients were examined by stethoscope, then by LUS for determination of DLT position, and then confirmed by FOB in the same patient.

Results

Three patients dropped out due to failed intubation, and only 117 cases were analyzed. Time was significantly longer for LUS than for auscultation and FOB and was insignificantly different between auscultation and FOB. Auscultation had 76.14% sensitivity, 34.48% specificity, and 65.81% accuracy in the determination of correct DLT placement. LUS had 92.05% sensitivity, 79.31% specificity, and 88.89% accuracy in detecting correct DLT placement. There was substantial agreement between LUS and FOB (κ = 0.705) and poor agreement between auscultation and FOB (κ = 0.104).

Conclusions

LUS can be used as a simple, noninvasive tool for detecting DLT placement with a substantial agreement with FOB.

Lung ultrasound is non-inferior to bronchoscopy for confirmation of double-lumen endotracheal tube positioning: a randomized controlled noninferiority study

BACKGROUND

Appropriate placement of left-sided double-lumen endotracheal tubes (LDLTs) is paramount for optimal visualization of the operative field during thoracic surgeries that require single lung ventilation. Appropriate placement of LDLTs is therefore confirmed with fiberoptic bronchoscopy (FOB) rather than clinical assessment alone. Recent studies have demonstrated lung ultrasound (US) is superior to clinical assessment alone for confirming placement of LDLT, but no large trials have compared US to the gold standard of FOB. This noninferiority trial was devised to compare lung US with FOB for LDLT positioning and achievement of lung collapse for operative exposure.

METHODS

This randomized, controlled, double-blind, noninferiority trial was conducted at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand from October 2017 to July 2019. The study enrolled 200 ASA classification 1-3 patients that were scheduled for elective thoracic surgery requiring placement of LDLT. Study patients were randomized into either the FOB group or the lung US group after initial blind placement of LDLT. Five patients were excluded due to protocol deviation. In the FOB group (n = 98), fiberoptic bronchoscopy was used to confirm lung collapse due to proper positioning of the LDLT, and to adjust the tube if necessary. In the US group (n = 97), lung ultrasonography of four pre-specified zones (upper and lower posterior and mid-axillary) was used to assess lung collapse and guide adjustment of the tube if necessary. The primary outcome was presence of adequate lung collapse as determined by visual grading by the attending surgeon on scale from 1 to 4. Secondary outcomes included the time needed to adjust and confirm lung collapse, the time from finishing LDLT positioning to the grading of lung collapse, and intraoperative parameters such has hypotension or hypertension, hypoxia, and hypercarbia. The patient, attending anesthesiologist, and attending thoracic surgeon were all blinded to the intervention arm.

RESULTS

The primary outcome of lung collapse by visual grading was similar between the intervention and the control groups, with 89 patients (91.8%) in the US group compared to 83 patients (84.1%) in the FOB group (p = 0.18) experiencing adequate collapse. This met criteria for noninferiority per protocol analysis. The median time needed to confirm and adjust LDLT position in the US group was 3 min (IQR 2-5), which was significantly shorter than the median time needed to perform the task in the FOB group (6 min, IQR 4-10) (p = 0.002).

CONCLUSIONS

In selected patients undergoing thoracic surgery requiring LDLT, lung ultrasonography was noninferior to fiberoptic bronchoscopy in achieving adequate lung collapse and reaches the desired outcome in less time.

TRIAL REGISTRATION

This study was registered at clinicaltrials.gov, NCT03314519 , Principal investigator: Kasana Raksamani, Date of registration: 19/10/2017.

Current Practice Issues in Thoracic Anesthesia

This review discusses the present strategies in lung separation, the various types of double-lumen tubes (DLTs), and the use of bronchial blockers (BBs). Methods of selecting the correct DLT size and the role of videolaryngoscopy in placing a DLT are reviewed. Mechanisms whereby inhaled anesthetics may be protective during one-lung ventilation (OLV) are highlighted. The risk and prevention of fire during thoracic procedures are discussed.