Tracheal width and left double-lumen tube size: a formula to estimate left-bronchial width

Common double-lumen tube selection methods overestimate adequate tube sizes in individual patients - a 3D reconstruction study

BACKGROUND

Appropriate selection of double-lumen tube sizes for one-lung ventilation is crucial to prevent airway damage. Current selection methods rely on demographic factors or 2D radiography. Prediction of left bronchial diameter is indispensable for choosing the adequate tube size. This prospective observational study investigates if current selection methods sufficiently predict individuals' left bronchial diameters for DLT selection compared to the 3D reconstruction.

METHODS

100 patients necessitating thoracic surgery with one-lung ventilation and left-sided double-lumen tubes, ≥ 18 years of age, and a set of chest X-rays and 2D thorax CT scans for 3D reconstruction of the left main bronchus were included between 07/2021 and 06/2023. The cross-validated prediction error and the width of the 95%-prediction intervals of the 3D left main bronchial diameter utilizing linear prediction models were based on current selection methods.

RESULTS

The mean bronchial diameter in 3D reconstruction was 13.6 ± 2.1 mm. The ranges of the 95%-prediction intervals for the bronchial diameter were 6.4 mm for demographic variables, 8.3 mm for the tracheal diameter from the X-ray, and 5.9 mm for bronchial diameter from the 2D-CT scans. Current methods violated the suggested '≥1 mm' safety criterion in up to 7% (men) and 42% (women). Particularly, 2D radiography overestimated women's left bronchial diameter. Current methods even allowed the selection of double-lumen tubes with bronchial tube sections greater than the bronchial diameter in women.

CONCLUSIONS

Neither demographic nor 2D-radiographic methods sufficiently account for the variability of the bronchial diameter. Wide 95%-prediction intervals for the bronchial diameter hamper accurate individual double-lumen tube selection. This increases women's risk of bronchial damage, particularly if they have other predisposing factors. These patients may benefit from 3D reconstruction of the left main bronchus.

TRIAL REGISTRATION

Not applicable.

Comparison of lung ultrasound technique <em>versus</em> clinical method to evaluate the accuracy of size and placement of left endobronchial double lumen tube in patients undergoing elective thoracic surgery: a prospective observational study

Anthropometric measurements like height and gender have been frequently found to be inaccurate in prediction of size of double lumen tube (DLT). A tracheal ultrasonography (TUS) is a technique that can be used to predict the size of DLT and its correct placement for lung isolation. We aim to check the accuracy of ultrasound over clinical methods. This prospective study included 68 patients undergoing elective thoracic surgery requiring one-lung ventilation (OLV) with DLT. The groups were assessed for the size of DLT by either anthropometric measurement using height and gender (Group C) or ultrasound method (Group U). Further, the accuracy of placement of DLT was assessed through, either lung auscultation in group C or various ultrasonographic and ventilatory parameters such as lung isolation in the first attempt (lung sliding and lung pulse sign), oxygenation status and peak airway pressure, in group U. Surgeon satisfaction score was also compared in both the groups. The accuracy of predicted DLT size between Group C and Group U was statistically significant (p=0.044). In Group C, 56% of patients showed a mismatch between the predicted DLT size and the actual size required, while in Group U, the mismatch was only 32.4%. The accuracy of DLT placement through group C was 41% as compared to 79% in Group U. Surgeon satisfaction score was also significantly higher in Group U as compared to Group C (p=0.0028). Thus, our study suggests that tracheal and chest ultrasonography for DLT size selection and placement for lung isolation is superior to clinical methods.

Research and development of the sOLVe Tube™ dual lumen endobronchial tube: from concept to construct

Introduction

Dual lumen endobronchial tubes (DLTs) are frequently used for lung isolation and one lung ventilation in thoracic surgery and other specialized clinical scenarios. Modern DLTs are large and rigid, and account for half of all tracheobronchial injuries. Their 70 year old design has numerous flaws which limit their safety and clinical utility. Our research team set out to design a new and improved DLT to mitigate these shortcomings, and then test the proposed device to ensure proper function.

Methods

Using published airway anatomy data and computed tomography imaging from 195 thoracic surgery patients, we designed a new DLT with a single size/configuration that would fit into adult surgery patients. This single "Universal design" was intended to replace both left and right sided 35Fr-41Fr DLTs (8 total products), while remaining small in diameter (35Fr). Other design goals included: 1) making intubation easier and safer, 2) allowing full sized therapeutic bronchoscopes to fit into this tube, 3) making the DLT more resistant to dislodgement. After design process completion the proposed dimensions were tested against 195 patients' left and right mainstem bronchi for radiographic fit. Once production prototypes were manufactured, they were tested in large adult Yorkshire pigs and fresh human cadavers for anatomic fit and performance.

Results

The proposed design passed the radiographic fit test in all 195 patients for both left and right mainstem endobronchial placement. Intubation was successful and deemed atraumatic in all pigs and cadavers, and the device appropriately fit in both the right and left mainstem bronchi. Lung isolation was successfully achieved and the device proved resistant to axial force dislodgement.

Conclusion

We propose a new design for a novel DLT meant to replace 8 currently supplied adult configurations with a single, one size/configuration fits all product that allows for large bore bronchoscopy and resists axial force dislodgement.

Choosing the correct-sized adult double-lumen tube: Quest for the holy grail

Appropriate size selection of double-lumen tubes (DLTs) for one-lung ventilation (OLV) in adults is still a humongous task. Several important factors are to be considered like patient height, gender, tracheal diameter, left main bronchial diameter, and cricoid cartilage transverse diameter. In addition to radiological assessment of the airway diameters, the manufacturing details of the particular DLT being used also play a significant role in size selection. Optimal positioning of the appropriately sized DLT is indispensable to avoid complications like airway trauma, cuff rupture, hypoxemia, and tube displacement. It is imperative to know whether the one-size-fits-all dictum holds for DLT size selection as claimed by certain studies. Further randomized studies are required for crystallizing standard protocols ascertaining the correct DLT size. This systematic review article highlights the various parameters employed for DLT size selection and explores the newer DLTs used for adult OLV.

Effect of Minimum Bronchial Cuff Volume of Left-Sided Double-Lumen Tube for One-Lung Ventilation on the Change in Bronchial Cuff Pressure during Lateral Positioning in Thoracic Surgery: A Prospective Observational Study

The minimum bronchial cuff volume (BCVmin) of a double-lumen tube (DLT) without air leaks during lung isolation may vary among individuals, and lateral positioning could increase the bronchial cuff pressure (BCP). We investigated the effect of initially established BCVmin (BCVi) on the change in BCP by lateral positioning. Seventy patients who underwent elective lung surgery were recruited and divided into two groups according to the BCVi obtained during anesthetic induction in each patient. Outcome analysis was conducted using data from 39 patients with a BCVi greater than 0 (BCVi > 0 group) and 27 with a BCVi of 0 (BCVi = 0 group). The primary outcome was a change in the value measured in the supine and lateral positions of the initially established BCP (BCPi; BCP at the time of BCVi injection), which was significantly larger in the BCVi > 0 group than in the BCVi = 0 group (1.5 (0.5-6.0) cmH₂O vs. 0.0 (0.0-1.0) cmH₂O; p < 0.001). BCVi was related to the left main bronchus (LMB) diameter (Spearman's rho = 0.676, p < 0.001) and the gap between the LMB diameter and the outer diameter of the bronchial cuff (Spearman's rho = 0.553, p < 0.001). Therefore, selecting a DLT size with a bronchial cuff that fits each patient's LMB may be useful in minimizing the change in BCP when performing lateral positioning during thoracic surgery. If the bronchial cuff requires unavoidable initial inflation, it is necessary to be aware that BCP may increase during lateral positioning and to monitor the BCP regularly if possible.

Association between body mass index and difficult intubation with a double lumen tube: A retrospective cohort study

STUDY OBJECTIVE

Obesity, defined by the World Health Organization as body mass index (BMI) ≥ 30.0 kg/m², is associated with adverse outcomes and challenges during surgery. Difficulties during endotracheal intubation, occur in 3-8% of procedures and are among the principal causes of anesthetic-related morbidity and mortality. Endotracheal intubation can be challenging in obese patients due to an array of anatomic and physiologic factors. Double lumen tubes (DLTs), the most commonly used airway technique to facilitate anatomic isolation of the lungs for one lung ventilation. However, DLTs can be difficult to properly position and are also more likely to cause airway injuries and bleeding when compared to conventional single lumen tubes. We investigated the association between BMI and difficult tracheal DLT intubation.

DESIGN

Retrospective cohort study.

SETTING

Operating room.

PATIENTS

We analyzed electronic records of adults having cardiac and thoracic surgery requiring general anesthesia and endotracheal intubation with DLT at the Cleveland Clinic between 2008 and 2021.

MEASUREMENTS

BMI, preoperative airway abnormalities and difficult intubation, defined as more than one intubation attempt, was assessed using multivariable logistic regression.

MAIN RESULTS

Among 8641 analyzed anesthetics requiring DLT, 1459 (17%) were difficult intubations. After adjusting for confounders, each 5 kg/m² increase in BMI was associated with a marginal increase of difficult intubation, odds ratio (OR) 1.06 (95% Confidence Interval [CI]: 1.002, 1.11; P = 0.040). Difficult intubation was not associated with airway abnormalities, estimated OR 0.85 (95% CI: 0.62, 1.17; P = 0.321). There was no interaction between known airway abnormalities and BMI (P = 0.894).

CONCLUSIONS

Difficult intubations with DLT remain common, but BMI is a weak predictor thereof. For example, an increase in BMI from 20 to 40 kg/m² corresponds to an increase in average absolute risk for difficult intubation from 16 to 19%, which probably is not clinically meaningful.

Intubation with vivasight double-lumen tube versus conventional double-lumen tube in adult patients undergoing lung resection: A retrospective analysis

Objectives

The present study was designed to compare outcomes in patients undergoing thoracic surgery using the VivaSight double-lumen tube (VDLT) or the conventional double-lumen tube (cDLT).

Design

A retrospective analysis of 100 patients scheduled for lung resection recruited over 21 consecutive months (January 2018-September 2019).

Setting

Single-center university teaching hospital investigation.

Participants

A randomized sample of 100 patients who underwent lung resection during this period were selected for the purpose to compare 50 patients in the VDLT group and 50 in the cDLT group.

Interventions

After institutional review board approval, patients were chosen according to inclusion and exclusion criteria and we created a general database. The 100 patients have been chosen through a random process with the Microsoft Excel program (Microsoft 2018, Version 16.16.16).

Measurements and Main Results

The primary endpoint of the study was to analyze the need to use fiberoptic bronchoscopy to confirm the correct positioning of VDLT or the cDLT used for lung isolation. Secondary endpoints were respiratory parameters, admission to the intensive care unit, length of hospitalization, postoperative complications, readmission, and 30-day mortality rate. The use of fiberoptic bronchoscopy was lower in the VDLT group, and the size of the tube was smaller. The intraoperative respiratory and hemodynamics parameters were optimal. There were no other preoperative, intraoperative, or postoperative differences between both groups.

Conclusions

The VDLT reduces the need for fiberoptic bronchoscopy, and it seems that a smaller size is needed. Finally, VDLT is cost-effective using disposable fiberscopes.

Double lumen tube: Size and insertion depth

Double lumen tubes (DLTs) are most commonly used to achieve one lung ventilation (OLV) in most thoracic surgical procedures unless contraindicated. Left-sided DLT (LDLT) is most commonly used nowadays for most thoracic surgical procedures. Though, the use of LDLT dates long back in history, two clinical and technical issues are yet to be resolved. The first issue is the ideal size of DLT which is defined as that which provides near-complete seal of the bronchial lumen without cuff inflation. There are no guidelines in literature which help in selecting the size of DLT. However, general consensus among thoracic anesthesiologists recommends the use of smaller sizes to avoid airway trauma. In our practice and for the last few years, we are using smaller size LDLT 35 F for females and 37 F for males with minimal airway trauma and had encouraging results. The second issue is the insertion depth of the LDLT. We have introduced a height-based formula to predict the insertion depth of LDLT with encouraging results. However, even with the use of the formula, we still recommend the use of fiberoptic bronchoscopic confirmation method for final positioning of the LDLT.

Lung separation in adult thoracic anesthesia

Thoracic anesthesia is mainly the world of OLV during anesthesia. The indications for OLV, classified as absolute or relative are more representative of the new concepts in OLV: It includes either the separation or the isolation of the lungs. Modern DLTs are most widely employed worldwide to perform OLV including the concept of one lung separation. Endobronchial blockers are a valid alternative to DLTs, and they are mandatory in the education of lung separation and in case of predicted difficult airways as they are the safest approach (with an awake intubation with an SLT through a FOB). Every general anesthesiologist should know how to insert a left-sided DLT, but he/she should also have in his technical luggage and toolbox, basic knowledge and minimal expertise with BBs, this option being considered a suitable alternative, particularly in emergency situation where the patient is already intubated and/or in case of difficult airways. One should keep in mind that extubation or re-intubation after DLT might be difficult too, and additional intubation tools are necessary for the safety conditions.

Compatibility of left-sided double-lumen endobronchial tubes with tracheal and bronchial dimensions: a retrospective comparative study

BACKGROUND

Double-lumen endobronchial tubes (DLT) continue to be the most widely used method for obtaining lung isolation during anesthesia. We compared recommendations for DLT size selection with radiologically assessed lower airway dimensions gathered from a large patient population.

METHODS

For this retrospective comparative study, we assessed computed tomography (CT) scans of 150 adults with no known airway pathologies. Using these scans, we measured the diameter and length of the trachea and the diameter of the mainstem bronchi. These airway dimensions were then compared to the dimensions of left-sided DLTs of three different manufacturers. Size selection was based on one standard textbook's recommendations.

RESULTS

We found the recommended DLT sizes were occasionally too small but more often too large, particularly in the endobronchial airway. With the DLT Vivasight-DL®, mismatching occurred in 28.7% (43/150) of the patients at the distal mainstem bronchus and 8% (12/150) at the tracheal level. This mismatching happened most often in females (left distal mainstem bronchus 34/68, 50%; trachea 9/68, 13.2%). Conversely, the DLT was more often too small for male patients in both the left main bronchus (SHER-I-BRONCH®: 8/82, 9.8%) and the trachea (SHER-I-BRONCH®: 2/82, 2.4%). The endobronchial tube portion was more often too long in females (Vivasight® DLT: 11/68, 16%) than males (9/82, 11%).

CONCLUSIONS

A considerable proportion of the recommended DLT sizes from all three manufacturers was incompatible with individual patient's lower airway dimensions.

Prediction of Left Double-Lumen Tube Size by Measurement of Cricoid Cartilage Transverse Diameter by Ultrasound and CT Multi-Planar Reconstruction

Background: Currently, there is no uniform standard for selecting the left double lumen tubes (LDLT). Advantages, such as safety and convenience of the ultrasonic technology, and measurement accuracy, make it more widely applied in the clinical anesthesia, and computed tomography (CT) multi-planar reconstruction (MPR) technology will certainly provide a more accurate measurement. For better application for thoracic surgery choice LDLT, relieving the injury to patients, and reducing the complications, this study will compare the two approaches. Methods: The first part, 120 cases of patients were selected according to the height and gender; recording the patient's optimum LDLT and measurement the transverse diameter of the cricoid cartilage (TD-C) by ultrasound and CT MPR, and then obtained the TD-C range measurement by ultrasound and CT MPR corresponding to different types of LDLT. The second part, total of 102 patients were divided into the ultrasound group and the CT MPR group. In the ultrasound group, TD-C was measured by ultrasound, the corresponding size for intubation was selected based on the conclusions derived from the first part. In the CT MPR group, TD-C was measured by CT MPR, the corresponding size of LDLT based on the conclusions derived from the first part. Results: In the first part, 120 patients were no significant difference in the basic characteristics (P > 0.05). The accuracy of selecting the LDLT by conventional experience, namely height and gender was 58.3%. Ultrasonic measurement TD-C range was as follows: 32 Fr <15.88, 35 Fr: 15.88-16.80, 37 Fr: 16.75-17.81, and 39 Fr > 17.80. CT MPR measurement TD-C range was as follows: 32 Fr <15.74, 35 Fr: 15.74-16.65, 37 Fr: 16.56-17.68, and 39 Fr > 17.65. In the second part, there was no significant difference in the basic characteristics between the two groups (P > 0.05). The accuracy of intubation in the ultrasound group was 90.2% and the corresponding in the CT MPR group was 94.1% (P > 0.05). Conclusions: The accuracy of selecting the LDLT based on TD-C is significantly higher than conventional experience; it can significantly reduce the post-operative complications and there was no statistical significance in the accuracy of LDLT selected for TD-C measurement by ultrasound vs. CT, and both of them could be safely used for the evaluation before intubation under anesthesia in thoracic surgery.

Double-lumen endotracheal tubes and bronchial blockers exhibit similar lung collapse physiology during lung isolation

PURPOSE

Double-lumen endotracheal tubes (DL-ETT) and bronchial blockers (BB) are frequently used to allow one-lung ventilation (OLV) during video-assisted thoracic surgery (VATS). Recently, faster lung collapse has been documented with a BB than with a DL-ETT. The physiologic mechanisms behind this faster collapse remained unknown. We aimed to measure ambient air absorption (Vresorb) and intra-bronchial pressure (Pairway) into the non-ventilated lung during OLV using DL-ETT and BB.

METHODS

Patients undergoing VATS and OLV for lung resection were randomly assigned to have measurements made of Vresorb or Pairway within the non-ventilated lung using either a DL-ETT or BB.

RESULTS

Thirty-nine patients were included in the analyses. The mean (standard error of the mean [SEM]) Vresorb was similar in the DL-ETT and BB groups [504 (85) vs 630 (86) mL, respectively; mean difference, 126; 95% confidence interval [CI], -128 to 380; P = 0.31]. The mean (SEM) Pairway became progressively negative in the non-ventilated lung in both the DL-ETT and the BB groups reaching [-20 (5) and -31 (10) cmH2O, respectively; mean difference, -11; 95% CI, -34 to 12; P = 0.44] at the time of the pleural opening.

CONCLUSIONS

During OLV before pleural opening, entrainment of ambient air into the non-ventilated lung occurs when the lumen of the lung isolation device is kept open. This phenomenon is prevented by occluding the lumen of the isolation device before pleural opening, resulting in a progressive build-up of negative pressure in the non-ventilated lung. Future clinical studies are needed to confirm these physiologic results and their impact on lung collapse and operative outcomes.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02919267); registered 28 September 2016.

Non-ventilated lung deflation during one-lung ventilation with a double-lumen endotracheal tube: a randomized-controlled trial of occluding the non-ventilated endobronchial lumen before pleural opening

PURPOSE

Lung deflation during one-lung ventilation (OLV) is thought to be faster using a double-lumen endotracheal tube (DL-ETT) than with a bronchial blocker, especially when the non-ventilated lumen is opened to allow egress of air from the operative lung. Nevertheless, ambient air can also be entrained into the non-ventilated lumen before pleural opening and subsequently delay deflation. We therefore hypothesized that occluding the non-ventilated DL-ETT lumen during OLV before pleural opening would prevent air entrainment and consequently enhance operative lung deflation during video-assisted thoracoscopic surgery (VATS).

METHODS

Thirty patients undergoing VATS using DL-ETT to allow OLV were randomized to having the lumen of the operative lung either open (control group) or occluded (intervention group) to ambient air. The primary outcome was the time to lung collapse evaluated intraoperatively by the surgeons. The T50, an index of rate of deflation, was also determined from a probabilistic model derived from intraoperative video clips presented in random order to three observers.

RESULTS

The median [interquartile range] time to lung deflation occurred faster in the intervention group than in the control group (24 [20-37] min vs 54 [48-68] min, respectively; median difference, 30 min; 95% confidence interval [CI], 14 to 46; P < 0.001). The estimated T50 was 32.6 min in the intervention group compared with 62.3 min in the control group (difference, - 29.7 min; 95% CI, - 51.1 to - 8.4; P = 0.008).

CONCLUSION

Operative lung deflation during OLV with a DL-ETT is faster when the operative lumen remains closed before pleural opening thus preventing it from entraining ambient air during the closed chest phase of OLV.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03508050); registered 27 September 2017.

Comparison of different size left-sided double-lumen tubes for thoracic surgery

Study Objective

The aim of this study is to see if there are any clinical differences between using 35 F DLT for all patients versus using patient height regardless of gender to estimate appropriate DLT size.

Design

Prospective randomized study.

Setting

University Hospital.

Patients

50 patients age ≤18 years, undergoing lung or esophageal surgery requiring OLV.

Interventions

Patients randomized to two groups (group-35F, group -DLT based on height).

Measurements and Main Results

Data collected include demographics, ASA status, airway assessment, number of intubation attempts, Cormack-Lehane grade, number of times DLT repositioned, incidence of sore throat, oxygen saturation at induction and oxygen saturation at 5 minutes and 10 minutes after OLV. There was no statistically significant difference in demographics, ASA classification, Mallampati score, number of intubation attempts, Cormack-Lehane grade, number of times DLT was repositioned, and incidence of sore throat. In height based DLT group the odds were higher for the incidence of sore throat in 37-41 F group. Oxygen saturation at induction, 5 minutes and 10 minutes after OLV are not statistically significant between the two groups. Conclusion: Our findings suggest that the majority of patients receive unnecessarily large DLTs for thoracic surgery, which not only makes intubation inherently more difficult but also increases their risk of postoperative sore throat.

Comparison between computerized tomography-guided bronchial width measurement versus conventional method for selection of adequate double lumen tube size

Background:

Selection of adequate size double lumen tube (DLT) is complicated by marked inter-individual variability in morphology and dimensions of tracheobronchial tree. Computerized tomography (CT)-guided left bronchus width measurement has been used to predict adequate size DLT in European and Singapore population; however, no such data exist for Indian population who are racially different. We compared the effect of DLT size selection based on CT-guided bronchial width measurement to the conventional method of DLT selection on the adequacy of both lungs isolation and on the safety margin of right-sided DLT.

Methods:

Fifty-five adults scheduled to undergo thoracotomy were enrolled in this prospective observational study. An appropriate size left- or right-sided DLT with outer diameter 0.5–1 mm smaller than the CT-measured bronchial width was selected for the isolation of lungs. Adequacy of separation was checked using fiberoptic bronchoscope. The safety margin of selected right-sided DLT size was calculated from CT-measured right upper lobe bronchus width and diameter of right upper lobe ventilation slot of the DLT.

Results:

Adequate separation of lungs was achieved in 92.7% of studied population, 90.9% in males, and 95.4% in females. Among these, 54.9% patients required different sized DLT as compared to conventional method. Overall safety of margin of right-sided DLTs was comparable between two methods of DLT selection (median [IQR] 4.8 (3.5–6.8) vs. 6.59 (3.5–7.8), P = 0.317). DLT size with adequate isolation of lung correlated with height, tracheal width (TW) on chest X-ray, and age of the patients. A formula to calculate DLT size based on these variable was derived.

Conclusion:

CT-measured bronchial width predicts the appropriate DLT size better than conventional method. In the absence of CT scan facility, patient height, age, and chest X-ray TW may be used to predict DLT size with reasonable accuracy.

Prediction of Double-Lumen Tube Size By Ultrasonography for Asian Women: A Prospective Observational Study

OBJECTIVE

To assess the agreement of the diameter of the cricoid cartilage by computed tomography and ultrasonography and to compare the accuracy of the left double-lumen tubes (DLTs) and right DLTs predicted by ultrasonography for Asian women.

DESIGN

Prospective observational study.

SETTING

Academic, tertiary care hospital.

PARTICIPANTS

Fifty female patients intubated with a left DLT and 50 female patients intubated with a right DLT.

INTERVENTIONS

No intervention.

MEASUREMENTS AND MAIN RESULTS

A radiologist measured the transverse cricoid diameter by computed tomography (CT), and an independent echographer measured the transverse cricoid diameter using ultrasonography. The size of the DLT was selected based on the cricoid diameter by ultrasonography. The agreement of the transverse cricoid diameter was assessed by computed tomography and ultrasonography. The accuracy of the DLT, the tracheal segment, and the bronchial segment were compared between the left intubation group and right intubation group. There was a good agreement between the transverse cricoid diameter measured by ultrasonography and CT (r = 0.946, p < 0.001). The overall accuracy of the DLTs was similar between the groups (86.0% v 92.0%, p = 0.318). There were no significant differences in the accuracy of the tracheal segment (96.0% v 94.0%; p = 1.000) and the bronchial segment (90.0% v 98.0%, p = 0.056).

CONCLUSIONS

The transverse diameter of the cricoid cartilage in most Asian women can be accurately measured by ultrasonography. The size of the DLT for Asian women can be predicted by ultrasonography measurement of the cricoid diameter.

Selective bronchial intubation for one-lung ventilation and independent-lung ventilation in pediatric age: state of the art

Selective bronchial intubation (SBI) to ventilate a single lung (one-lung ventilation, OLV) or to apply separate lung ventilation (independent-lung ventilation, ILV) can be frequently required under general anesthesia in pediatrics, mainly in video assisted thoracoscopy surgery, in the postoperative care of cardio-thoracic surgery, and for the treatment of lung pathologies with unilateral prevalence in intensive care. In children over 6-8 years of age SBI, OLV and ILV can be performed using marketed double-lumen tubes (DLTs). In neonates, infants and younger children the application of ILV is limited due to the lack of DLTs. For children of this age, a specific DLT for ILV was developed (Marraro Paediatric Endobronchial Bilumen Tube®) but is currently available only as a special product. The DLT represents the device of choice for OLV and ILV while the use of bronchial blocker is suggested as an alternative to achieve the SBI and the OLV when suitable DLTs are not available. Different catheters types can be used as bronchial blocker. If SBI is not possible using DLT or bronchial blocker, a conventional single-lumen tube of adequate length can allow SBI in all pediatric ages. Using the bronchial blocker and single lumen tube it is possible to perform OLV but it is impossible to apply ILV. The main complications of SBI and DLT are largely due to limited operator experience. Airway trauma, dislodgment and obstruction of the devices are quite frequent and can lead to severe hypoxia if not recognized and treated early.

Practice patterns of left-sided double-lumen tube: Does it match recommendation from literature - A single-centre observational pilot study

Context:

Choosing appropriate-size double-lumen tube (DLT) has always been a challenge as it depends on existing guidelines based on gender, height, tracheal diameter (TD), or personal experience. However, there are no Indian data to match these recommendations.

Aim:

To find out whether the size of DLT used correlates with height, weight, TD, or left main stem bronchus diameter (LMBD). We also documented clinical consequences of any of our current practice.

Setting and Design:

Single-center observational pilot study.

Subjects and Methods:

Prospective, observational study of 41 patients requiring one-lung ventilation with left-side DLT. The choice of DLT was entirely on the discretion of anesthesiologist in charge of the case. Data were collected for TD, LMBD, height, weight, age, sex, and amount of air used in the tracheal and bronchial cuff. Any intraoperative complications and difficulty in isolation were also noted.

Statistical Analysis:

The statistical analysis was done with the National Council of Statistical Software version 11.

Results:

Average TD and LMBD were 16.5 ± 0.9 and 10.7 ± 0.8 mm for males and 14.2 ± 1.1 and 9.4 ± 1.1 mm for females, respectively. There was a weak correlation between DLT size and height (R² = 0.0694), TD (R² = 0.3396), and LMBD (R² = 0.2382) in the case of males. For females, the correlation between DLT size and height (R² = 0.2656), TD (R² = 0.5302), and LMBD (R² = 0.5003) was slightly better.

Conclusion:

Although there was a weak correlation between DLT size and height, TD, and LMBD, the overall intraoperative outcome and lung isolation were good.

Dimensional Variations of Left-Sided Double-Lumen Endobronchial Tubes

Background

Tube size selection is critical in ventilating patients' lungs using double-lumen endobronchial tubes (DLTs). Little information about relevant parameters is readily available from manufacturers. The aim of this study is to provide reference data for relevant dimensions of conventionally available DLTs.

Methods

In this study in a benchmark in vitro setup, several dimensional parameters of four sizes of left-sided double-lumen endobronchial tubes from six different manufacturers were assessed, such as distances and diameters of tube shaft, cuff lengths, and diameters as well the angle at the tip.

Results

Endobronchial tubes of ostensibly the same size revealed wide variation in measured parameters between brands from different manufacturers. In some parameters, there was an overlap between different sizes from the same manufacturer, i.e., diameters and distances did not increase with increasing nominal endobronchial tube size. The information about dimensions of endobronchial tubes provided by manufacturers' leaflets is insufficient.

Conclusions

Endobronchial tube size selection carries unnecessary uncertainty because clinically relevant parameters are unknown and vary considerably between different manufacturers.

[Risk factors for intraoperative hypoxemia during monopulmonary ventilation: an observational study]

BACKGROUND

Left double-lumen endotracheal tubes have been widely used in thoracic, esophageal, vascular, and mediastinal procedures to provide lung separation. Lacking clear objective guidelines, anesthesiologists usually select appropriately sized double-lumen endotracheal tubes based on their experience with 35 and 37Fr double-lumen endotracheal tubes, which are the most commonly used. We hypothesized the patients with a left main bronchus of shorter length (<40mm) had a greater chance of experiencing desaturation during one lung ventilation, due to obstruction in the orifice of the left upper lobe with the bronchial tube.

METHODS

We included 360 patients with a left double-lumen intubated between September 2014 and August 2015. The patient's age, sex, height, weight, and underlying disease were recorded along with type of surgical procedure and the desaturation episodes. In addition, the width of the trachea and the width and length of the left bronchus were measured using computed tomography.

RESULT

Patients with a left main bronchus length of less than 40mm who underwent intubation with a left double-lumen endotracheal tubes had significantly higher incidence of desaturation (Odds Ratio (OR: 8.087)) during one-lung ventilation. Other related factors of patients identified to be at risk of developing hypoxia were diabetes mellitus (OR: 5.368), right side collapse surgery (OR: 4.933), and BMI (OR: 1.105).

CONCLUSIONS

We identified that patients with a left main bronchus length of less than 40mm have a great chance of desaturation, especially if other desaturation risk factors are present.

Risk factors for intraoperative hypoxemia during monopulmonary ventilation: an observational study

Background

Left double-lumen endotracheal tubes have been widely used in thoracic, esophageal, vascular, and mediastinal procedures to provide lung separation. Lacking clear objective guidelines, anesthesiologists usually select appropriately sized double-lumen endotracheal tubes based on their experience with 35 and 37 Fr double-lumen endotracheal tubes, which are the most commonly used. We hypothesized the patients with a left main bronchus of shorter length (<40 mm) had a greater chance of experiencing desaturation during one lung ventilation, due to obstruction in the orifice of the left upper lobe with the bronchial tube.

Methods

We included 360 patients with a left double-lumen intubated between September 2014 and August 2015. The patient's age, sex, height, weight, and underlying disease were recorded along with type of surgical procedure and the desaturation episodes. In addition, the width of the trachea and the width and length of the left bronchus were measured using computed tomography.

Result

Patients with a left main bronchus length of less than 40 mm who underwent intubation with a left double-lumen endotracheal tubes had significantly higher incidence of desaturation (Odds Ratio (OR: 8.087)) during one-lung ventilation. Other related factors of patients identified to be at risk of developing hypoxia were diabetes mellitus (OR: 5.368), right side collapse surgery (OR: 4.933), and BMI (OR: 1.105).

Conclusions

We identified that patients with a left main bronchus length of less than 40 mm have a great chance of desaturation, especially if other desaturation risk factors are present.

Automated measurement of tracheal and main bronchial diameters: a feasibility study

BACKGROUND

A thoracic computed tomography scan is rarely used to help choose the appropriate double-lumen tube. Nowadays, bronchial measurements can be automated using dedicated software. The aim of this prospective monocentric study was to compare manual and automated measurements of the diameter of the trachea and both main bronchi in adult patients free from a history of lung surgery or disease.

METHODS

Diameters of the trachea and of the main stem bronchi were measured by trained physicians or automatically using Thoracic Volume Computer Assisted Reading software (GE Healthcare, Chicago, IL, USA). Manual measurements were considered as the goal standard.

RESULTS

Two hundred and forty-three patients were assessed for eligibility, 216 were allocated to intervention and 173 analyzed: 102 males and 71 females (61.4±13.9 years, 169.7±9.4 cm, 73.3±16.8 kg). Reliability between the two investigators was poor (20.8±9.0% of measurements with a difference >10%). Intraclass correlation coefficient (ICC) and its confidence interval at 95% (ICC [95% CI]) was 0.97 [0.96; 0.98] for the maximal diameter and 0.94 [0.92; 0.95] for the minimal diameter of the trachea (P<0.01 for both). ICC [95% CI] was 0.97 [0.94; 0.98] for the maximal diameter and 0.93 [0.90; 0.95] for the minimal diameter of the right main bronchus (P<0.01 for both). ICC [95% CI] was 0.96 [0.95; 0.97] for the maximal diameter and 0.93 [0.90; 0.95] for the minimal diameter of the left main bronchus (P<0.01 for both).

CONCLUSIONS

This feasibility study has mixed results since automated measurements were not feasible in around 20% of the cases.

Radiological evaluation of airway - What an anaesthesiologist needs to know!

Airway management forms the foundation of any anaesthetic management. However, unanticipated difficult airway (DA) and its sequelae continue to dread any anaesthesiologist. In spite of development of various clinical parameters to judge DA, no single parameter has proved to be accurate in predicting it. Radiological evaluation may help assess the aspects of patient's airway not visualised through the naked eye. Starting from traditional roentgenogram to ultramodern three-dimensional printing, imaging may assist the anaesthesiologists in predicting DA and formulate plan for its management. Right from predicting DA, it has been used for estimating endotracheal tube sizes, assessing airway pathologies in paediatric patients and planning extubation strategies. This article attempts to provide exhaustive overview on radiological parameters which can be utilised by anaesthesiologists for prediction of DA.

Selection of an appropriate left-sided double-lumen tube size for one-lung ventilation among Asians

Context:

Selecting an appropriate size double-lumen tube (DLT) for one-lung ventilation has always been a challenge as most choose it based on experience or using the existing guidelines based on gender and height.

Aims:

The aim of this study was to determine if the appropriate choice of this tube could be based on the patients’ height, weight, tracheal diameter (TD), or the left main stem bronchus diameter (LMBD) and also to determine the relationship between height and depth of insertion among Asians.

Subjects and Methods:

This was a retrospective review of 179 patients who were intubated with a left-sided DLT and also had a posterior-anterior view of a digital chest radiograph for tracheal and left main bronchus diameter measurements. Additional data collected included patients’ demographics and DLT size used.

Results:

There were 123 (68.7%) males and 56 (31.3%) females with an overall mean age of 33.3 ± 16.3 years. Majority of the males (48.8%) used a size 39 Fr while females (46.4%) used a 35 Fr. There were weak correlations between DLT size with height (male: R² = 0.222; female: R² = 0.193), DLT size with weight (male: R² = 0.109; female: R² = 0.211), DLT size with TD (male: R² = 0.027); female: R² = 0.016), and DLT size with LMBD (male: R² = 0.222; female: R² = 0.193). There was a good correlation between depth of DLT inserted with patient's height for both genders.

Conclusion:

The appropriate size of the left-sided DLT could not be predicted based on patients’ height, weight, tracheal or left main bronchus diameter alone in Asians; however, the depth of insertion of the tube was dependent on the height in both genders.

Cricoid and left bronchial diameter in the pediatric population

BACKGROUND

Lung isolation in the pediatric population can be problematic. The diameter and length of the right and left mainstem bronchi are not well described in young children. Information regarding these measurements may help determine the appropriate size of endotracheal tubes for endobronchial intubation as well as the development of lung isolation devices for the pediatric population. The present study is based on computed tomography (CT) measurements to evaluate airway dimensions. The goal of this study was to define the relationship between the diameters of the left mainstem bronchus (LMSB) and the cricoid ring, and to study the effect of age, weight, and height on these dimensions.

METHODS

The two-dimensional CT images of 102 children, ranging in age from 1 month to 10 years, undergoing radiological evaluation unrelated to airway symptomatology were examined. The cricoid dimensions (anteroposterior and transverse diameters) were measured using transverse plane images. The LMSB diameter was measured below the carina along the long axis of left main bronchus. Univariate regression analysis was used to determine whether one or more of the variables (age, gender, height, weight) had a predictable relationship with the cricoid and the LMSB diameters.

RESULTS

The cricoid as well as the LMSB diameters increase with age, height, and weight. The relationship between the cricoid diameter and the LMSB diameter remains constant across all ages with a ratio of 0.78 ± 0.14. This ratio was slightly larger for girls than boys (0.81 ± 0.16 vs 0.77 ± 0.13).

CONCLUSION

The cricoid to LMSB ratio (relationship) remains constant with respect to age, height, and weight.

Left double-lumen tube with or without a carinal hook: A randomised controlled trial

BACKGROUND

Left double-lumen tracheal tubes (DLTs), with or without a hook to engage the carina, remain the standard device for lung isolation during anaesthesia.

OBJECTIVE

The purpose of the study was to compare these DLTs with and without a hook.

DESIGN

A randomised, controlled, single-blinded study.

SETTING

University hospital.

PARTICIPANTS

One hundred and eighty-four patients undergoing lung resection.

MAIN OUTCOME MEASURE

Time required to position the tube from the introduction of the tube into the mouth to confirmation of correct placement in the supine position.

RESULTS

Baseline characteristics were well balanced between the groups. Time to place DLTs was similar in both groups: median (interquartile range, IQR) 81.0 (50.0 to 146.2) s for DLTs without a hook and 67.5 s (45.0 to 138.7) for DLTs with a hook (P = 0.43). The incidence of adequate position at the first attempt was 68.5% in the No hook group and 69.6% in the Hook group (P = 0.95). Patients in both groups suffered similar incidences of sore throat at day 0 and day 1 (P = 0.80 and P = 0.20, respectively). No major lesion of the vocal cords or tracheobronchial tree was discovered and the incidence of minor lesions was similar in both groups.

CONCLUSION

When a DLT is used, the presence of a carinal hook gives neither advantage nor added complications.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00969683.

Measurement and analysis of the tracheobronchial tree in Chinese population using computed tomography

Objective

To ascertain accurate measurements of, and the relationships between, the normative parameters of the tracheobronchial trees in the Chinese population using multi-slice spiral computed tomography (CT) and multi-planar reconstruction (MPR).

Materials and Methods

Measurements were performed on 2107 patients who underwent thoracic CT scans in the PLA General Hospital. The lengths of the trachea and the main stem bronchi, and the sizes of the subcarinal angle were obtained through CT or MPR imaging. Multi-variance analyses were performed to detect potential correlations between obtained parameters.

Results

The mean length of the trachea was 104.9 ± 13.4 mm (107.8 ± 13.2 mm for men and 101.4 ± 12.8 mm for women). The mean lengths of the right and left main stem bronchi were 13.6 ± 4.3 and 48.3 ± 6.5 mm, respectively. The right bronchus angle and the left bronchus angle were 34.9 and 42.5 degrees, respectively. Significant gender differences were found in all the parameters measured except for the angle of the right upper lobe bronchus. There are no statistically significant correlations among these parameters.

Conclusions

The normal reference values and the likely ranges of distribution of the tracheobronchial trees in the Chinese population have been established. Significant gender differences exist in the dimensions of the trachea, with the exception of the Right upper bronchial angle (RUA).

Novel patterns for the growing main bronchi in the human fetus: an anatomical, digital and statistical study

Purpose

Intensive progress in prenatal medicine results in performing airway management in the fetus affected by life-threatening congenital malformations. This study aimed to examine age-specific reference intervals and growth dynamics for length, proximal and distal external transverse diameters, and projection surface areas of the two main bronchi at varying gestational ages, including their relative growth in length and projection surface area.

Materials and methods

Using anatomical dissection, digital image analysis and statistics, length, proximal and distal external transverse diameters, and projection surface areas of the right and left main bronchi were examined in 73 human fetuses (39 males, 34 females) aged 14–25 weeks, derived from spontaneous abortions and stillbirths.

Results

Statistical analysis showed no sex differences. Between the 14 and 25th week of gestation, the lengths of the right and left main bronchi increased from 1.43 ± 0.18 to 3.18 ± 0.39 mm, and from 2.97 ± 0.16 to 7.58 ± 1.95 mm, in accordance with the functions: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 4.850 + 2.452 x \; \text{ln}\left( {\text{Age}} \right) \pm 0.400\;{\text{and}}\;y = - 15.005 + 7.093x \; \text{ln} \left( {\text{Age}} \right) \pm 0.579 $$\end{document}y=−4.850+2.452xln(Age)±0.400andy=−15.005+7.093xln(Age)±0.579, respectively. The proximal external transverse diameters of the right and left main bronchi varied from 2.13 ± 0.41 to 4.24 ± 0.20 mm, and from 1.84 ± 0.06 to 3.67 ± 0.66 mm, following the logarithmic models: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 8.666 + 4.018x \; \text{ln}{\rm (Age)} \pm 0.367\;{\text{and}}\;y = - 6.938 + 3.305x{\text{ ln(Age) }} \pm 0.323 $$\end{document}y=−8.666+4.018xln(Age)±0.367andy=−6.938+3.305xln(Age)±0.323, respectively. The distal external transverse diameter rose from 2.09 ± 0.47 to 4.24 ± 0.20 mm, as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 8.723 + 4.021x{\text{ ln(Age)}} \pm 0.392 $$\end{document}y=−8.723+4.021xln(Age)±0.392 for the right main bronchus, and from 1.85 ± 0.04 to 3.67 ± 0.66 mm, like \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 6.924 + 3.280x{\text{ ln(Age)}} \pm 0.348 $$\end{document}y=−6.924+3.280xln(Age)±0.348 for the left one. On either side, there were no statistically significant differences between values of the proximal and distal transverse diameters of the main bronchus. The projection surface areas of the right and left main bronchi ranged from 2.95 ± 0.19 to 13.34 ± 2.12 mm², and from 5.57 ± 0.21 to 28.52 ± 5.24 mm², as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 10.212 + 0.943x{\text{ Age}} \pm 1.739 $$\end{document}y=−10.212+0.943xAge±1.739 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 19.119 + 1.875x{\text{ Age}} \pm 3.054 $$\end{document}y=−19.119+1.875xAge±3.054. The two main bronchi revealed a proportionate increase in both length and projection surface area, since the right-to-left bronchial length ratio and the right-to-left bronchial projection surface area ratio were stable, 0.41 ± 0.07 and 0.47 ± 0.08, respectively, throughout the analyzed period.

Conclusions

The main bronchi show no sex differences. The right and left main bronchi grow logarithmically in length and external transverse diameter, and linearly in projection surface area. The right and left main bronchi evolve proportionately, with the right-to-left bronchial ratios of 0.41 ± 0.07 for length, and 0.47 ± 0.08 for projection surface area.

How to choose the double-lumen tube size and side: the eternal debate

Although disposable double-lumen tubes have been used for many years, there is still controversy regarding what size and which side to use for thoracic procedures requiring lung isolation. Thoracic and nonthoracic anesthesiologists often debate performance, efficiency, and outcome of small and large double-lumen tubes, and left- and right-sided tubes. This article focuses on current data in the literature and expert opinion on the topic.

Prediction of optimal endotracheal tube cuff volume from tracheal diameter and from patient height and age: a prospective cohort trial

PURPOSE

Endotracheal tube intra-cuff pressure should be maintained between 20 and 30 cmH(2)O to prevent damage to the tracheal wall. However, cuff pressure is rarely measured, and clinicians estimate cuff pressure poorly. The goal of the present study was to predict the cuff volume that produces optimal cuff pressure either from tracheal diameter or from patient height and age.

METHODS

In the development phase, initial cuff pressure and cuff volume were measured in 240 patients. Optimal cuff volume, defined as the volume halfway between the volumes required to produce cuff pressures of 20 and 30 cmH(2)O, was determined in each patient. Then, regression equations relating optimal cuff volume to tracheal diameter on chest X-ray, and between optimal cuff volume and a combination of height and age, were calculated. The primary outcome was the proportion of patients in a validation set (n = 104) who achieved a cuff pressure of 20-30 cmH(2)O when cuff volume was selected by each regression formula.

RESULTS

Only 28% of the cuffs were optimally inflated using clinical criteria during the development phase. There was good correlation between optimal cuff volume and tracheal diameter and moderate correlation between optimal cuff volume and both height and age. Predicted cuff volume was more likely to provide optimal cuff pressure when based on tracheal diameter (65% of patients) than when based on both height and age (45% of patients).

CONCLUSIONS

Optimal cuff volume was better estimated from tracheal diameter and patient height and age than from the manual palpation method.

Can ultrasound be useful for predicting the size of a left double-lumen bronchial tube? Tracheal width as measured by ultrasonography versus computed tomography

STUDY OBJECTIVE

To correlate tracheal width as measured by ultrasound with width measured by computed tomography (CT), and to evaluate the possible role of ultrasound in the selection of the proper size of left-sided double-lumen endotracheal tubes (LDLTs).

DESIGN

Two independent, prospective, observational clinical studies (Study 1 and Study 2).

SETTING

University hospital.

PATIENTS

Study 1 included 25 patients and Study 2 included 20 adult thoracic surgery patients who required a LDLT during anesthesia.

INTERVENTIONS AND MEASUREMENTS

In Study 1, CT measurements of tracheal width were made at the coronary plane 0.5 cm above the sternoclavicular joint; CT measurements of the left main bronchus diameter were made 1 cm below the carina. Ultrasound measurement of tracheal width was performed just above the sternoclavicular joint in the transversal section. In Study 2, patients' tracheas were intubated with a LDLT based on ultrasound measurements. The frequencies of incorrect selections of LDLT and unsatisfactory lung collapse were analyzed.

MAIN RESULTS

There was a strong correlation between tracheal width as measured by ultrasound and tracheal width (r=0.882, P<0.001) and left main bronchus width (r=0.832, P<0.001) as measured by CT. In 5 cases (25%), the incorrect LDLT by ultrasound was selected; and one (5%) was found to have an unsatisfactory lung collapse.

CONCLUSION

Measurement of the outer tracheal width by ultrasound can be a useful method for predicting the diameter of left main bronchus and for selecting a LDLT.

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.

Anesthesia for thoracic surgery in morbidly obese patients

PURPOSE OF REVIEW

This review considers the anesthetic management of obese patients undergoing thoracic surgery. Extremely or morbidly obese patients differ from patients of normal weight in several ways. Obese patients have altered anatomy and physiology, and usually have associated comorbid medical conditions that may complicate their operative course and increase their risks for postoperative complications.

RECENT FINDINGS

During anesthetic induction and laryngoscopy for tracheal intubation the morbidly obese patient should be in the reverse Trendelenburg position with the head and neck elevated above the table. Placement of a double-lumen tube should be no more difficult in an obese patient than in a normal-weight patient. There are no clear advantages for any of the commonly available inhalational anesthetic agents and each can be used for general anesthesia.

SUMMARY

With proper attention to their special needs, the morbidly obese patient can safely undergo thoracic surgery and one-lung ventilation.