Comparison of three techniques to inflate the bronchial cuff of left polyvinylchloride double-lumen tubes

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.

Comparative study of a modified double-lumen tube ventilation control connector and traditional connector in clinical use: a randomised-controlled trial

Background

A Y-shaped rotatable connector (YRC) for double-lumen tubes (DLT) is invented and compared with the traditional connector (Y-shaped connector, YC).

Methods

Sixty patients with ASA grade I-III, aged ≥ 18 years, who needed to insert a DLT for thoracic surgery were recruited and assigned into the YRC group (n = 30) and the YC group (n = 30) randomly. The primary endpoints included the inhaled air concentration (Fi) and the exhaled air concentration (Et) of sevoflurane before and after the switch between two-lung ventilation and one-lung ventilation at different times, positioning time, and switching time. The secondary endpoints were the internal gas volume of the two connectors, airway pressure, and the sputum suction time.

Results

The Et and Fi of the YRC group and the YC group were significantly different (all p < 0.05) at 5s, 10s, and 30s after the patient switched from two-lung ventilation to one-lung ventilation. The positioning time of the YRC group was less than YC group (89.75 ± 14.28 s vs 107.80 ± 14.96 s, p < 0.05), as well as the switching time (3.60 ± 1.20 s vs 9.05 ± 2.53 s, p < 0.05) and the internal gas volume (17.20 ml vs 24.12 ml). There was no difference in airway pressure and the sputum suction time in two groups.

Conclusion

Compared with YC, YRC was beneficial for maintaining depth of anesthesia, improves efficiency for the switch between one-lung and two-lung ventilation, and shortens the tube positioning time.

1. YRC was beneficial to maintain the stability of anesthesia depth.

2. YRC improves the conversion efficiency for one-lung and two-lung ventilation.

3. YRC shortens the positioning time.

A Comparison of the Required Bronchial Cuff Volume Obtained by 2 Cuff Inflation Methods, Capnogram Waveform-Guided Versus Pressure-Guided: A Prospective Randomized Controlled Study

BACKGROUND

Double-lumen endobronchial tubes (DLTs) are used for one-lung ventilation (OLV) during thoracic surgery. Overinflation into the bronchial cuff causes damage to the tracheobronchial mucosa, whereas underinflation leads to an incomplete collapse of the nonventilated lung or incomplete ventilation of the ventilated lung. However, how to determine the appropriate bronchial cuff volume and pressure during OLV is unclear. The objective of this study is to compare the required bronchial cuff volume for lung separation obtained by 2 different cuff inflation methods under closed- and open-chest conditions.

METHODS

A total of 64 patients scheduled to undergo elective thoracic surgery requiring OLV were recruited. Left DLTs were used for both right- and left-sided surgery. The patients were randomly assigned to 1 of 2 inflation-type groups to estimate the bronchial cuff volume. In the capnogram waveform-guided bronchial cuff inflation group (capno group, n = 27), the bronchial cuff was inflated until a capnometer sampling gas containing CO2 from the nonventilated lung displayed a flat line. The corresponding bronchial cuff volume and pressure were then recorded. In the pressure-guided bronchial cuff inflation group (pressure group, n = 29), the bronchial cuff was inflated by a cuff inflator to a pressure of 20 cm H2O. Lung separation was confirmed when a flat line of a capnometer was observed after gas sampling from the nonventilated lung.

RESULTS

Under closed-chest conditions, the bronchial cuff sealing volume for the capno group was significantly lower than that for the pressure group (mean [standard deviation {SD}], 1.00 [0.65] mL vs 1.44 [0.59] mL, mean difference, -0.44; 97.5% confidence interval [CI], -0.78 to -0.11; P = .010). Under open-chest conditions, the bronchial cuff sealing volume for the capno group was also significantly lower than that for the pressure group (mean [SD], 0.65 [0.66] mL vs 1.22 [0.45] mL, mean difference, -0.58; 97.5% CI, -0.88 to -0.27; P < .001).

CONCLUSIONS

The lowest cuff volume providing an air-tight bronchial seal was obtained by the capnogram waveform-guided bronchial cuff inflation method. Since the cuff volume required to achieve an air-tight seal decreases after opening the chest, readjustment of the bronchial cuff volume to prevent bronchial cuff damage to the tracheobronchial mucosa after opening the chest may be advisable.

CPAP Effects on Oxygen Delivery in One-Lung Ventilation During Minimally Invasive Surgical Ablation for Atrial Fibrillation in The Supine Position

OBJECTIVE

In minimally invasive surgical ablation for atrial fibrillation during video-assisted thoracoscopy surgery, one-lung ventilation (OLV) with a double- lumen tube is commonly employed. In contrast with the majority of thoracic procedures, the patient lies supine; thus, the protective effect of gravity is lost and intrapulmonary shunt remains high. To decrease intrapulmonary shunt and to increase oxygenation, many strategies are utilized: high inspiratory fraction of oxygen (F_IO₂), positive end-expiratory pressure on the ventilated lung, and continuous positive airway pressure (CPAP) on the deflated lung.

DESIGN

The authors performed a prospective, single- center, randomized study to evaluate the effect of additional CPAP in the nonventilated lung on oxygen delivery during surgical ablation for atrial fibrillation via video-assisted thoracoscopy in the supine position.

SETTING

University hospital Centro Cardiologico Monzino IRCCS, Milano, Italy.

PARTICIPANTS

Twenty-two patients scheduled for minimally invasive surgical ablation for atrial fibrillation.

INTERVENTIONS

The patients underwent pressure-controlled ventilation, adjusting inspiratory pressure to obtain a tidal volume of 7 mL/kg while keeping F_IO₂ constantly 1.0, a respiratory rate to maintain arterial partial pressure of carbon dioxide (PaCO₂) between 35 and 40 mmHg, and positive end-expiratory pressure of 5 cmH₂O. During OLV, inspiratory pressure was reduced to obtain a tidal volume of 5 mL/kg, maintaining F_IO₂ of 1.0, a respiratory rate to maintain PaCO₂ between 35 and 40 mmHg with capnothorax of 10 cmH₂O. The patients were then randomized into the CPAP group (CPAP 10 cmH₂0 on deflated lung) and NO CPAP group. Inotropic agents (dopamine or dobutamine) were used if cardiac index fell below 1.5 L/min/m².

MEASUREMENTS AND MAIN RESULTS

Twenty-two patients were enrolled, randomized, and completed the study. Median age was 62 years. The difference in arterial partial pressure of oxygen between the 2 groups was shy of significance, p = 0.16. Cardiac index progressively increased during OLV until the end of the procedure in both groups (p < 0.01) and was maintained above 1.5 mL/min/m² during the whole study time. Arterial oxygen content remained stable during the entire procedure in both groups (p = 0.27). Oxygen delivery index (DO₂I) increased significantly during the procedure (p < 0.01); nevertheless, the difference in DO₂I between the CPAP and NO CPAP group was nonsignificant (p = 0.61). Intrapulmonary shunt (Q_s/Q_t) increased during OLV (p < 0.01 for the time effect) and remained high until total lung ventilation was reintroduced. No difference in Q_s/Q_t was observed between the CPAP and NO CPAP groups (p = 0.98). Similarly, mean pulmonary artery pressure increased significantly during OLV and remained high at the end of the procedure in both groups (time effect p < 0.01).

CONCLUSIONS

During OLV for atrial fibrillation surgical ablation in the supine position, CPAP on the deflated lung seemed to be ineffective to reduce Q_s/Q_t or to increase arterial partial pressure of oxygen and DO₂I, provided cardiac output was maintained above 1.5 L/min/m².

Effect of lateral positioning on the bronchial cuff pressure of a left-sided double-lumen endotracheal tube during thoracic surgery: study protocol for a prospective observational study

INTRODUCTION

Correct pressure is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. An inadequate bronchial cuff pressure (BCP) can cause air leak and interfere with visualisation of the surgical field, whereas an excessive pressure BCP can lead to cuff-related complications. Based on several reports that cuff pressure could alter after a positional change when using an endotracheal tube, we hypothesise that a change from the supine position to the lateral decubitus position, which is essential for thoracic surgery, would affect the BCP of the DLT.

METHODS AND ANALYSIS

This prospective, single-centre, observational study will enrol 74 patients aged 18-70 years undergoing elective lung surgery from September 2018 to April 2019. The primary outcome will be the change in the 'initially established BCP' (maximum BCP not exceeding 40 cm H₂O with no air leak in the supine position) after lateral decubitus positioning. BCP and air leak will be assessed in each patient position during inflation of the cuff with air in 0.5 mL increments from 0 to 3 mL. Secondary outcomes will include the incidence of BCP exceeding 40 cm H₂O after the initial established value and that of a change in the smallest bronchial cuff volume without air leak after a change to the lateral position. The relationship between the change in BCP and airway pressure, compliance and body mass index after lateral positioning will be investigated.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the Declaration of Helsinki and supervised by the Daegu Catholic University Medical Center institutional review board (study approval number CR-18-111). All patients will receive information about the study and will need to provide written informed consent before enrolment. The results will be presented at an international meeting and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03656406; Pre-results.

Augmentation of curved tip of left-sided double-lumen tubes to reduce right bronchial misplacement: A randomized controlled trial

Background

During intubation with a blind technique, a left-sided double-lumen tube (DLT) can be misdirected into the right bronchus even though its curved tip of the bronchial lumen turns to the left. This right bronchial misplacement may be associated with the tip angle of DLTs. We thus performed a randomized trial to test the hypothesis that the DLT with an acute tip angle enters the right bronchus less frequently than the tube with an obtuse tip angle.

Methods

We randomized surgical patients (n = 1427) receiving a polyvinyl chloride left-sided DLT. Before intubation, the curved tip was further bent to an angle of 135° and kept with a stylet inside in the curved-tip group, but not in the control group. After the tip was inserted into the glottis under direct or video laryngoscopy, the stylet was removed and the DLT was advanced into the bronchus with its tip turning to the left. We checked which bronchus was intubated, and the time and number of attempts for intubation. After surgery, we assessed airway injury, sore throat, and hoarseness. The primary outcome was the incidence of right bronchial misplacement of the DLT.

Results

DLTs were misdirected into the right bronchus more frequently in the control group than in the curved-tip group: 57/715 (8.0%) vs 17/712 (2.4%), risk ratio (95% CI) 3.3 (2.0–5.7), P < 0.001. The difference was significant in the use of 32 (P = 0.003), 35 (P = 0.007), and 37 (P = 0.012) Fr DLTs. Intubation required longer time (P < 0.001) and more attempts (P = 0.002) in the control group. No differences were found in postoperative airway injury, sore throat and hoarseness.

Conclusions

Before intubation of left-sided DLTs, augmentation of the curved DLT tip reduced the right bronchial misplacement and facilitated intubation without aggravating airway injury.

Using the capnograph to confirm lung isolation when using a bronchial blocker

The endotracheal tube and bronchial blocker combination is an accepted lung isolation technique used during thoracic surgery. A reliable and inexpensive method of confirming lung isolation that uses capnographic monitoring of the bronchial blocker central lumen is presented. As the bronchial blocker balloon is inflated, lung isolation is confirmed when the normal respiratory variation of carbon dioxide (CO(2)) is replaced by a persistent plateau CO(2) waveform.

Gravity is an important determinant of oxygenation during one-lung ventilation

BACKGROUND

The role of gravity in the redistribution of pulmonary blood flow during one-lung ventilation (OLV) has been questioned recently. To address this controversial but clinically important issue, we used an experimental approach that allowed us to differentiate the effects of gravity from the effects of hypoxic pulmonary vasoconstriction (HPV) on arterial oxygenation during OLV in patients scheduled for thoracic surgery.

METHODS

Forty patients with chronic obstructive pulmonary disease scheduled for right lung tumour resection were randomized to undergo dependent (left) one-lung ventilation (D-OLV; n=20) or non-dependent (right) one-lung ventilation (ND-OLV; n=20) in the supine and left lateral positions. Partial pressure of arterial oxygen (PaO2) was measured as a surrogate for ventilation/perfusion matching. Patients were studied before surgery under closed chest conditions.

RESULTS

When compared with bilateral lung ventilation, both D-OLV and ND-OLV caused a significant and equal decrease in PaO(2) in the supine position. However, D-OLV in the lateral position was associated with a higher PaO2 as compared with the supine position [274.2 (77.6) vs. 181.9 (68.3) mmHg, P<0.01, analysis of variance (ANOVA)]. In contrast, in patients undergoing ND-OLV, PaO2 was always lower in the lateral as compared with the supine position [105.3 (63.2) vs. 187 (63.1) mmHg, P<0.01, ANOVA].

CONCLUSION

The relative position of the ventilated vs. the non-ventilated lung markedly affects arterial oxygenation during OLV. These data suggest that gravity affects ventilation-perfusion matching independent of HPV.

Performance of electrical impedance tomography in detecting regional tidal volumes during one-lung ventilation

BACKGROUND

Electrical impedance tomography (EIT) is becoming a new medical imaging modality for continuous monitoring of regional lung function in the intensive care unit or operating room. The aim of our study was to evaluate the performance of EIT in detecting regional tidal volumes in patients during volume-controlled mechanical ventilation of one or both lungs.

METHODS

Ten adult patients undergoing elective thoracic surgery were included. EIT measurements were performed with the Goe-MF II EIT system. Data were collected before surgery during ventilation of both, the right and left lungs. Tidal volumes of 800 and 400 ml were applied during bilateral and unilateral ventilation, respectively.

RESULTS

Ventilation-related impedance changes determined in the whole chest cross-section during the right and left lung ventilation did not significantly differ from each other and were equal to 47.6+/-5.6% and 48.5+/-7.8% (mean+/-SD) of the value determined during bilateral ventilation. During unilateral ventilation, EIT clearly separated the ventilated and non-ventilated lung regions; nevertheless, ventilation-related impedance changes were also detected at the non-ventilated sides in areas corresponding to 3.4+/-4.1% and 12.4+/-6.9% of the scan halves during ventilation of the left and right lung, respectively. Changes in global tidal volumes were adequately detected by EIT during both bilateral and unilateral lung ventilation.

CONCLUSION

Although good separation of the ventilated and non-ventilated sides of the chest was possible, the data indicate that reliable quantification of regional tidal volumes during asymmetric or inhomogeneous distribution patterns requires regions-of-interest analysis.

Rapid deflation of the bronchial cuff of the double-lumen tube after decreasing the concentration of inspired nitrous oxide

Deflationary phenomena of the endotracheal tube cuff may occur after inspired nitrous oxide (N(2)O) concentrations are reduced, but deflationary phenomena of the double-lumen tube (DLT) cuff have not been investigated. In this study, tracheal and bronchial cuffs of left-sided Mallinckrodt (Athlone, Ireland) DLTs were inflated with air, 40% N(2)O, or 67% N(2)O (Air, N40, or N67 groups, respectively) in 24 patients undergoing thoracic surgery; 40 min later, O(2) was substituted for N(2)O in some of the patients in the N40 group (N40-c group). Intracuff gas volumes, N(2)O concentrations, and cuff compliance were also measured. Both tracheal and bronchial cuff pressures significantly increased in the Air group but decreased in the N67 group. Neither pressure significantly changed in the N40 group, but both decreased in the N40-c group after terminating N(2)O anesthesia; the time required for bronchial cuff pressures to decrease by half (12.0 +/- 5.5 min) was less than that for tracheal cuff pressures (31.2 +/- 11.0 min, P < 0.01). The volume change in the N40-c group was not significantly different between the tracheal and bronchial cuffs, but tracheal cuff compliance was significantly higher than bronchial compliance. Therefore, filling DLT cuffs with 40% N(2)O stabilizes cuff pressure during anesthesia with 67% N(2)O, but bronchial cuffs deflate more quickly than tracheal cuffs after cessation of N(2)O administration through smaller compliance.

IMPLICATIONS

We demonstrated that after cessation of nitrous oxide (N(2)O) administration, bronchial N(2)O-filled cuffs of the double-lumen tube deflate more rapidly than tracheal cuffs. To avoid insufficient separation of the lungs by the bronchial cuff, a frequent check of the cuff pressure is recommended after the inspired N(2)O concentration is decreased.

Two-lung and one-lung ventilation in patients with chronic obstructive pulmonary disease: the effects of position and F(IO)2

We compared the effects of position and fraction of inspired oxygen (F(IO)2) on oxygenation during thoracic surgery in 24 consenting patients randomly assigned to receive an F(IO)2 of 0.4 (eight patients, Group 0.4), 0.6 (eight patients, Group 0.6), or 1.0 (eight patients, Group 1.0) during the periods of two-lung (TLV) and one-lung ventilation (OLV) in the supine and lateral positions. TLV and OLV were maintained while the patients were first in the supine and then in the lateral position for 15 min each. Thereafter, respiratory mechanical data were obtained, and arterial blood gas samples were drawn. Pao2 decreased during OLV compared with TLV in both the supine and lateral positions. In all three groups, Pao2 was significantly higher during OLV in the lateral than in the supine position: 101 (72-201) vs 63 (57-144) mm Hg in Group 0.4; 268 (162-311) vs 155 (114-235) mm Hg in Group 0.6; and 486 (288-563) vs 301 (216-422) mm Hg in Group 1.0, respectively (P < 0.02, Wilcoxon's signed rank test). We conclude that, compared with the supine position, gravity augments the redistribution of perfusion as a result of hypoxic pulmonary vasoconstriction, when patients are in the lateral position, which explains the higher Pao2 during OLV.

IMPLICATIONS

This study compares oxygenation during thoracic surgery during periods of two-lung and one-lung ventilation with patients in the supine and lateral positions when using three different fraction of inspired oxygen values. Arterial oxygen tension was decreased in all three groups during one-lung ventilation in comparison with the two-lung ventilation values, but the decrease was significantly less in the lateral, compared with the supine position.

Respiratory mechanics and gas exchange during one-lung ventilation for thoracic surgery: the effects of end-inspiratory pause in stable COPD patients

OBJECTIVE

To examine the effects of end-inspiratory pause (EIP) of different durations on pulmonary mechanics and gas exchange during one-lung ventilation (OLV) for thoracic surgery.

DESIGN

A prospective clinical study.

SETTING

A university hospital.

PARTICIPANTS

Eleven patients undergoing elective pulmonary resection with pulmonary hyperinflation on their preoperative pulmonary function studies.

INTERVENTIONS

Patients were anesthetized, paralyzed, and intubated with a double-lumen endotracheal tube. Their lungs were ventilated with a Siemens 900C ventilator (Siemens; Solna, Sweden), with constant inspiratory flow. Tidal volume, respiratory rate, and inspiratory time were kept constant during the study.

MEASUREMENTS AND RESULTS

During one-lung ventilation in the lateral decubitus position, three levels of EIP (0%, 10%, and 30%) were applied to the dependent lung in random order. After 15 minutes on the given ventilatory pattern, end-inspiratory and end-expiratory occlusions of at least 5 seconds were performed to obtain respiratory mechanics data. Arterial blood gas samples were drawn to assess gas exchange. Altering the duration of end-inspiratory pause from 0% to 30% resulted in a significant increase in intrinsic positive end-expiratory pressure (PEEPi) from 4.1 cm H2O to 7.0 cm H2O. Arterial oxygenation was significantly decreased from 109.7 to 80.5 mmHg and there was a significant negative correlation between the value of partial pressure of arterial oxygen (PaO2) and PEEPi by altering the duration of end-inspiratory pause. From the preoperative pulmonary function studies, the value of functional residual capacity (FRC) (% predicted) showed a significant negative correlation with the PaO2 changes. Partial pressure of arterial carbon dioxide (PaCO2) was not altered significantly by increasing the duration of end-inspiratory pause.

CONCLUSION

During the period of OLV in the lateral position of patients with preexisting pulmonary hyperinflation, the magnitude of PEEPi increased and oxygenation decreased significantly, whereas the efficacy of ventilation was not changed by the addition of an end-inspiratory pause to the ventilatory pattern. Because arterial oxygenation is affected by the presence of pulmonary hyperinflation, the method of ventilation should take into account the magnitude of preoperative pulmonary hyperinflation.

Rupture of the left main-stem bronchus by the tracheal portion of a double-lumen endobronchial tube

We report a rupture of the left main-stem bronchus following the insertion of a left-sided double-lumen endobronchial tube in a 76-yr-old woman with a short trachea. A fiberoptic bronchoscope was not used during the initial insertion of the tube and the depth of insertion resulted in approximately 5 cm in excess of the optimal level for this patient. The rupture had been caused by the tracheal portion of the double-lumen tube. This damage may have been avoided if a fiberoptic bronchoscope was used routinely as an introducer and for positioning of the endobronchial tube under direct vision.

Evaluation of an approach to choosing a left double-lumen tube size based on chest computed tomographic scan measurement of left mainstem bronchial diameter

OBJECTIVE

Evaluation of an approach to choosing left double-lumen tube size based on chest computed tomographic (CT) scan measurement of left bronchial diameter.

DESIGN

Prospective.

SETTING

The operating rooms of a university hospital.

PARTICIPANTS

Patients scheduled for elective thoracic surgery.

INTERVENTIONS

Patients had their left bronchial diameter measured on the preoperative chest CT scan. Left double-lumen tube size for the individual patient was chosen from a protocol based on left bronchial diameter.

MEASUREMENTS AND MAIN RESULTS

The double-lumen tube size was considered appropriate for the patient if some air leak was detected when the bronchial cuff was deflated and if airtight seal of the left bronchus was obtained with a bronchial cuff volume of 2 mL or less. In 17 of 20 patients, the double-lumen tube size fulfilled both criteria. In 3 women with left bronchi measuring 10 mm or less, the bronchus was sealed without any air in the bronchial cuff of size 35 Fr left double-lumen tubes. In 1 patient, who was excluded from the study, the double-lumen tube size was chosen based on measurement of the left bronchial diameter on chest radiograph because of motion artifact on the chest CT scan.

CONCLUSIONS

Chest CT scan measurement of left bronchial diameter can successfully guide the choice of left double-lumen tube size for an individual patient. In individuals with a small left bronchus measuring less than 10.0 mm in diameter, currently available adult double-lumen tube sizes will tightly wedge in their bronchus.

Placement of left double-lumen endobronchial tubes with or without a stylet

PURPOSE

This study was designed to determine if leaving a stylet in the left Bronch-Cath endobronchial tube (DLT) for the entire intubating procedure improves the accuracy of placement on the initial attempt, without introducing complications.

METHODS

Sixty ASA 1-3 patients were randomized to one of two groups. In Group 1 (n = 30), the stylet was retained for the entire intubation procedure and in Group 2 (n = 30), the stylet was removed once the bronchial cuff had passed the vocal cords. In both groups, the DLT was turned 110 degrees counterclockwise and advanced until resistance was encountered. Placement was assessed by auscultation and fibreoptic bronchoscopy (FOB). After surgery, the DLT was replaced by a single-lumen endotracheal tube. The thoracic surgeon (blinded to the method of intubation, and using a FOB) assessed the appearance of the tracheobronchial mucosa.

RESULTS

The two groups were similar with respect to sex, height, weight, DLT size, surgeon and expertise of the laryngoscopist. When the stylet was retained, the DLT was correctly placed 60% of the time compared with 17%, if the stylet was removed, (P = 0.001). Seven out of 30 DLTs in Group 2 were initially placed into the right mainstem bronchus, (P = 0.005). The average time to confirmation of correct tube placement by FOB was increased in Group 2, (P = 0.01). Although the observed incidence of left bronchial, mucosal petechiae and erythema was greater in Group 2, this was not statistically significant, (P = 0.063).

CONCLUSION

Retaining the stylet for the entire intubation procedure allows for a more rapid, accurate placement of the DLT without increasing the incidence of tracheobronchial mucosa injury.

The relationship between left mainstem bronchial diameter and patient size

Knowledge of a patient's left mainstem bronchial diameter would provide a useful guide to choosing the appropriate double-lumen tube (DLT) size for that patient. Therefore, the authors investigated the possibility that left bronchial diameter could be predictably estimated from a patient's size and sex. The routine preoperative chest X-rays of 100 adult male and female patients of known age, height, and weight were examined. The left bronchial diameter was measured on the posteroanterior (PA) chest x-ray, and a formula was used to correct for the magnification of intrathoracic structures encountered on the PA view. Multiple linear regression analysis was used to determine whether one or more of the variables (age, sex, height, weight, and body surface area) had a predictable relationship to the left bronchial diameter. The left mainstem bronchial diameter in men and women (mean +/- SD/range) was 12.4 +/- 1.5 mm/9.5 to 15.5 mm, and 10.7 +/- 1.0 mm/9.0 to 14.0 mm, respectively. In female patients, none of the variables was significantly correlated with bronchial diameter. In male patients, age (p = 0.013) and height (p = 0.008) individually produced a statistically significant prediction of endobronchial diameter. The following formula was best predictive of left bronchial diameter in men: diameter (mm) = 0.032 x age (year) + 0.072 x height (cm) -2.043. Applying this formula to mean age 50 who are 158, 172, and 185 cm in height, the predicted left bronchial diameters are 11.0, 12.0, and 13.0 mm, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)