Optimal depth of insertion of left-sided double-lumen endobronchial tubes cannot be predicted from body height in below average-sized adult patients

Depth of double-lumen endobronchial tube: a comparison between real practice and clinical recommendations using height-based formulae

BACKGROUND

The depth of double-lumen endobronchial tube (DLT) is reportedly known tobe directly proportional to height and several height-based recommendations have beensuggested. This retrospective study was designed to find out the difference between calculated depths using height-based formulae and realistic depths in clinical practice of DLTplacement by analyzing pooled data from patients intubated with left-sided DLT.

METHODS

The electronic medical records of adults, intubated with DLT from February 2018to December 2020, were reviewed. Data retrieved included age, sex, height, weight, andsize and depth of DLT. The finally documented DLT depth (depth final, DF) was comparedwith the calculated depths, and the relationship between height and DF was also evaluated.A questionnaire on endobronchial intubation method was sent to anesthesiologists.

RESULTS

A total of 503 out of 575 electronic records of consecutive patients were analyzed.Although the relationship between height and DF was shown to have significant correlation(Spearman's rho = 0.63, P < 0.001), DF was shown to be significantly greater than calculated depths (P < 0.001). Despite 57.1% of anesthesiologists have knowledge of clinical recommendations to anticipate size and depth of DLT, no one routinely utilizes those recommendations.

CONCLUSIONS

Anesthesiologists tend to place DLTs in a deeper position than expected whendepths are calculated using height-based recommendations. Although such discrepanciesmay not be clinically meaningful, efforts are needed to standardize the methods of endobronchial intubation to prevent potential complications associated with malposition.

Insertion depth of left-sided double-lumen endobroncheal tube: A new predictive formula

Background:

In the field of thoracic anesthesia, it is well-established practice that the insertion depth of left-sided double-lumen tube (LDLT) is achieved after checking its position via fiberoptic bronchoscopy (FOB). Several studies have shown positive correlation between body height (BH) and the optimal insertion depth of a LDLT. Each of these studies has developed a formula for proper insertion depth of the LDLT. In this study, we prospectively studied our patients whose tracheas were intubated correctly with LDLT using FOB confirmation and examined the optimal insertion depth of LDLT aiming at finding a formula suitable for our patients.

Methods:

After obtaining the institutional review board approval of College of Medicine Research Centre, King Saud University, we recruited 41 adult patients who underwent thoracic surgery with one-lung ventilation (OLV). The study included patients whose procedure required placement of a LDLT. The optimal insertion depth of the LDLT was confirmed using FOB. The following variables were recorded, the patient's sex, age, BH, and the final correct insertion depth of the LDLT (cm) measured from the corner of the mouth. The results of LDLT insertion depth in our study were compared to another published five studies. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 22 software (SPSS Inc., Chicago, IL, USA).

Results:

Positive correlation was found between BH (cm) and insertion depth of LDLT (cm) since r = 0.744 (P < 0.05). Also, positive correlation was found between the LDLT size (Fr) and insertion depth of LDLT (cm) since r = 0.792 (P < 0.05) where r is Pearson's correlation coefficient. By fit curve (Curve Estimation), we were able to get the predicted equation for our cases as follow: the insertion depth of LDLT (cm) =0.249 × (BH)^0.916 with significant correlation to the other five formulae (P < 0.05).

Conclusion:

In the present study we have obtained a novel formula to predict the insertion depth of LDLT. Currently we are conducting a verification study on a larger sample size to attest its validity. However at this stage and till the results are released we cannot judge on it. We believe time will tell about the validity of our formula for our patients.

Efficacy of a New Blind Insertion Technique of Arndt Endobronchial Blocker for Lung Isolation: Comparison With Conventional Bronchoscope-Guided Insertion Technique-A Pilot Study

This study aimed to find other methods of blind insertion of Arndt endobronchial blocker (AEB) for lung isolation when a fiberoptic bronchoscope (FOB) is unavailable.We compared the effectiveness and safety of 3 insertion techniques of AEB: Gum elastic bougie (GEB)-, bougie combined with cricoid displacing (BCD)-, and fiberoptic bronchoscope (FOB)-guided insertion. Seventy-eight patients undergoing esophageal procedure and requiring left thoracotomy were randomly assigned to 1 of 3 groups: GEB group, BCD group, and FOB group. We recorded the successful placement of AEBs at first attempt, placement time, malposition of AEBs in supine and lateral decubitus position, the bronchus injury score, and other complications.The successful placement of AEB for the first attempt was 22/26, 25/26, and 26/26 patients in GEB, BCD, and FOB groups, respectively. The placement times in GEB and BCD groups were longer than those in the FOB group (P < 0.05). AEB malposition occurred in 1/26, 2/26, 1/26 patients after lateral decubitus position, and AEBs were repositioned in 5/26, 3/26, 1/26 patients by FOB due to poor lung isolation in GEB, BCD, and FOB groups, respectively. There was no difference for the bronchus injury scores and other complications among 3 groups (P > 0.05).Bougie and cricoid displacing-guided blind insertion of AEB seems to be a novel method, which is an effective and safe alternative when FOB was unavailable.

Comparison between transthoracic lung ultrasound and a clinical method in confirming the position of double-lumen tube in thoracic anaesthesia. A pilot study

OBJECTIVE

To compare the ability of lung ultrasound and a clinical method in the confirmation of a selective bronchial intubation by left double-lumen tube in elective thoracic surgery.

MATERIAL AND METHODS

A prospective and blind, observational study was conducted in the setting of a university hospital operating room assigned for thoracic surgery. A single group of 105 consecutive patients from a total of 130, were included. After blind intubation, the position of the tube was confirmed by clinical and ultrasound assessment. Finally, the fiberoptic bronchoscopy confirmation as a reference standard was used to confirm the position of the tube. Under manual ventilation, by sequentially clamping the tracheal and bronchial limbs of the tube, clinical confirmation was made by auscultation, capnography, visualizing the chest wall expansion, and perceiving the lung compliance in the reservoir bag. Ultrasound confirmation was obtained by visualizing lung sliding, diaphragmatic movements, and the appearance of lung pulse sign.

RESULTS

The sensitivity of the clinical method was 84.5%, with a specificity of 41.1%. The positive and negative likelihood ratio was 1.44 and 0.38, respectively. The sensitivity of the ultrasound method was 98.6%, specificity was 52.9%, with a positive likelihood ratio of 2.10 and a negative likelihood ratio of 0.03. Comparisons between the diagnostic performance of the 2 methods were calculated with McNemar's test. There was a significant difference in sensitivity between the ultrasound method and the clinical method (P=.002). Nevertheless, there was no statistically significant difference in specificity between both methods (P=.34). A p value<.01 was considered statistically significant.

CONCLUSION

Lung ultrasound was superior to the clinical method in confirming the adequate position of the left double-lumen tube. On the other hand, in confirming the misplacement of the tube, differences between both methods could not be ensured.

Positioning of double-lumen tubes based on the minimum peak inspiratory pressure difference between the right and left lungs in short patients: a prospective observational study

BACKGROUND

Peak inspiratory pressures (PIPs) during one-lung ventilation (OLV) have served as a clinical marker that could indirectly verify the proper positioning of double-lumen tubes (DLTs). Patients of short stature are highly susceptible to initial DLT malpositioning.

OBJECTIVES

We investigated the usefulness of positioning left-sided DLTs using minimum PIP differences between the right and left lungs by comparing with the previously used method of auscultation without fibreoptic bronchoscopy (FOB). We also evaluated the difference in PIPs between the two lungs during OLV after the DLT was ideally positioned with FOB examination.

DESIGN

Prospective, observational study.

SETTING

A university hospital.

PATIENTS

One hundred and two female patients of short stature (≤160  cm).

INTERVENTIONS

Verification of DLT position was conducted by three sequential steps: auscultation; minimising the difference in PIP during each OLV; and verifying the resulting position by FOB.

MAIN OUTCOME MEASUREMENTS

Fibreoptic bronchoscopic view results of DLT position followed by the position adjustment using the minimum PIP difference method.

RESULTS

Repositioning the DLT using the minimum PIP difference led to clinically successful positioning of the DLT in 88% of patients and a more ideal placement of the tube than auscultation alone (69.6 vs. 11.8%, P <0.001). Additionally, the ideal position of DLTs verified by FOB showed that PIP differences were zero or ±1  mmHg in 93% of patients.

CONCLUSION

Positioning the DLT based on the minimum PIP difference between the right and left lungs as a supplementation to routine auscultation serves as an easy and reliable method for DLT positioning and may improve the accuracy of DLT positioning as an adjuvant to FOB in short patients.

TRIAL REGISTRATION

Clinicaltrial.gov identifier: NCT01533012.

Practice patterns in choice of left double-lumen tube size for thoracic surgery

BACKGROUND

Some anesthesiologists choose smaller than body size-appropriate left sided double-lumen tubes (DLTs) ("down-size") for lung isolation in an attempt to limit the risk of airway trauma. There are few data on the effects of DLT size on intraoperative outcome measures.

METHODS

In 300 adults undergoing thoracic surgery requiring lung isolation, we conducted a prospective pilot study to evaluate whether the use of 35 FR DLT, regardless of gender and/or height (care standard of two investigators), was associated with a similar incidence of intraoperative hypoxemia, lung isolation failure, or need for DLT repositioning during surgery (noninferiority) than with the conventional goal of inserting the largest possible DLT (care standard of two other investigators). DLT insertion position was immediately confirmed with fiberoptic bronchoscopy after direct laryngoscopic placement and after lateral positioning.

RESULTS

The combined incidence of transient hypoxemia, inadequate lung isolation, or need for DLT repositioning during surgery did not differ among patients receiving 35, 37, or 39 FR DLT, regardless of gender or height. Despite the high frequency of 35 FR DLT use, 2% of patients required further down-sizing due to the inability to introduce the DLT into the left mainstem bronchus or when no inflation of the bronchial cuff was needed for lung isolation.

CONCLUSIONS

Under the conditions of this pilot study, the use of smaller than conventionally sized DLT was not associated with any differences in clinical intraoperative outcomes.

Which device should be considered the best for lung isolation: double-lumen endotracheal tube versus bronchial blockers

PURPOSE OF REVIEW

This review is a clinical comparison between double-lumen endotracheal tubes and bronchial blockers to determine which device is considered the best for lung isolation.

RECENT FINDINGS

Double-lumen endotracheal tubes and bronchial blockers have been found to be clinically equivalent in terms of performance in providing lung collapse for patients with normal airways. In the last five years, however, numerous reports have indicated a preference for the use of bronchial blockers in patients with airway abnormalities. For nonthoracic anesthesiologists who have limited experience in thoracic anesthesia cases, none of the devices (double-lumen tubes or bronchial blockers) have been shown to provide any advantage while in use due to a high incidence of unrecognized malpositions. Overall, each device provides advantages depending upon the case, such as absolute lung separation with a double-lumen endotracheal tube or the use of a bronchial blocker in a difficult airway for a patient requiring lung isolation.

SUMMARY

Double-lumen endotracheal tubes and bronchial blockers should be part of the armamentarium of every anesthesiologist involved in lung isolation techniques and every device should be tailored to specific case needs.