The authors developed a formula for predicting the accurate depth of DLT insertion into the appropriate bronchus based on height as follows \[The predicted insertion depth of left DLT (cm) equals 0.249 × (BH)0.916\] \[R\]. That pilot study showed comparable correlations between five formulae \[Brodsky et al, Bahk and Oh R, Takita et al, Chow et al, Lin\]. However, that formula developed has not been validated yet. We hypothesized that previously published formula would predict the accurate depth of left-sided DLT insertion. We aimed to investigate the efficacy of this formula to estimate the optimum insertion depth of the DLT using a flexible bronchoscope and decrease the incidence of DLT displacement into the appropriate bronchus, the need for bronchoscopic adjustment, and complications including soreness of throat and mucosal injury.
Accurate placement of the double-lumen tube \[DLT\], the commonly used tool to provide one-lung ventilation during thoracic surgery, is a real challenge for the thoracic anesthesiologists. Optimal DLT depth, defined as the blue endobronchial cuff below the carina, would decrease the incidence of obstructing the trachea and the contralateral bronchus (Brodsky). Additionally, deep insertion of the bronchial cuff of the DLT would obstruct the upper lobe bronchus (Brodsky). The careful adjustment of the depth and optimal positioning of the DLT using a flexible fiberoptic bronchoscope need a skilled anesthesiologist to reduce the time to DLT intubation. (Charles D. Boucek et al) There are several methods have been described to predict the proper depth of DLT insertion. Chow et al. documented the validity of the developed formula based on the clavicular-to-carinal distance of trachea and height in 78% of patients studied. Brodsky et al. demonstrated that a height-and-gender-based formula could predict the depth of DLT insertion. Liu et al. reported an accurate depth of DLT insertion in 90% of patients studied measuring the distance between the vocal cord and carina according to the chest CT.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
65
A left-sided double-lumen tube was introduced beyond the vocal cords when the train-of-four stimulation of the ulnar nerve revealed 1 or 2 twitches, the stylet was removed, the double-lumen tube was rotated 90° counterclockwise and then advanced blindly to the predicted depth of insertion.
The optimal position of the double-lumen tube, defined as the inflated endobronchial cuff is placed in the left main bronchus just below the carina without herniation, which was confirmed using a flexible bronchoscope in both supine and lateral decubitus positions.
If the endobronchial cuff was placed too deeply or too proximal, subsequently, the double-lumen tube was withdrawn or advanced, respectively, using the flexible bronchoscope until the optimum position of the double-lumen tube was achieved.
King Saud University
Riyadh, Saudi Arabia
The rate of optimum position of the double-lumen tube
The rate of optimum position of a left-sided DLT without further adjustments, defined as the inflated endobronchial cuff is placed in the left main bronchus just below the carina without herniation
Time frame: for 15 minutes after double-lumen tube insertion
The calculated predicted depth of insertion
The predicted insertion depth of the DLT was calculated using the formula \[0.249 x (BH) 0.916\] using an application an application on the smart phone
Time frame: immediately before induction of general anesthesia
The initial depth of insertion
The "initial depth of insertion," was measured using the external centimeter markings on the DLT's lumen at the level of incisors
Time frame: for 15 minutes after double-lumen tube insertion
Position of the double-lumen tube with the flexible bronchoscope
The position of the DLT with the flexible bronchoscope would be rated either (1) optimally placed, (2) too far out, or (3) too far in
Time frame: for 15 minutes after double-lumen tube insertion
The need for bronchoscopic adjustments
If the endobronchial cuff was placed too deeply or too proximal, subsequently, the DLT was withdrawn or advanced, respectively, using the flexible bronchoscope until the optimum position of the DLT was achieved. The optimizing maneuvers were recorded
Time frame: for 15 minutes after double-lumen tube insertion
The final correct depth of insertion
the "final correct depth of insertion", defined as the distance from the distal opening of the bronchial lumen to the corner of the mouth, was measured with a flexible bronchoscope passing through the bronchial lume
Time frame: for 15 minutes after double-lumen tube insertion
Time to final correct double-lumen tube positioning
Time to final correct DLT positioning from time of laryngoscopy was recorded
Time frame: for 25 minutes after double-lumen tube insertion
Changes in heart rate
Postintubation changes in heart rate was recorded
Time frame: for 25 minutes after double-lumen tube insertion
Changes in mean arterial blood pressure
Postintubation changes in mean arterial blood pressure was recorded
Time frame: for 25 minutes after double-lumen tube insertion
Changes in peripheral oxygen saturation
Postintubation changes in peripheral oxygen saturation was recorded
Time frame: for 25 minutes after double-lumen tube insertion
Degree of lung collapse
degree of lung collapse was rated as excellent, good, poor, or very poor
Time frame: for 30 minutes after start of surgery
The incidence of soreness of throat
Patients were asked about the occurrence and severity of postoperative sore throat
Time frame: for 24 hours after start of surgery
The incidence of mucosal injury
The incidence of mucosal injury using the flexible bronchoscope was reported after intubation using the double-lumen tube
Time frame: for 40 minutes after double-lumen tube insertion
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