The Feasibility And Safety Of Selective Lobar Blockade During Thoracic Surgery

The primary objective of lung separation techniques, which also called separation of the two lungs, is to selectively interrupt ventilation to one lung or to a portion of a lung. Therefore, lung separation are vital and life-saving techniques for intrathoracic surgical procedures and in the management of critically ill patients who require differential lung ventilation, which provides one-lung ventilation(OLV) or selective lobar collapse during the operation, prevents spillage of pus or blood from an infected lung to a noninvolved lung and facilitates surgical exposure.OLV is inevitably associated with gross changes in respiratory physiology. Unilateral ventilation creates an obligatory right-to-left transpulmonary shunt due to continuing blood flow through the collapsed, non-ventilated lung, and results in mixed venous blood. Although there is a significant diversion of blood flow from the non-ventilated lung to the ventilated lung after the initiation of hypoxic pulmonary vasoconstriction response, hypoxia and ventilator associated lung injury might cause by ventilation-perfusion mismatch and the above factors.In patients with previous lobectomy or pneumonectomy requiring subsequent pulmonary resection or in patients with limited pulmonary reserve resulting from severe pulmonary disease, such as destroyed lung, requiring contralateral procedures, OLV with the use of a double-lumen endobronchial tube (DLT) is impossible to avoid lobe(s) ventilation for these situations, hypoxia can not be alleviated even though applying conventional protective ventilation strategies such as increasing fraction of inspired oxygen (FiO2) to 1,continuous positive airway pressure ventilation or insufflation of oxygen to the non-ventilated lung, and pressure control ventilation or positive end-expiratory pressure ventilation to the dependent lung. The surgeries can only be completed with two-lung ventilation using lower tidal volumes (VT) and more rapid respiratory rates previously, however, partial expansion of the lung may hinder surgical activity and slow the progress of the procedure. During video-assisted thoracic surgery (VATS), if a staple or a trocar is placed on a noncollapsed lung free from air in the lung parenchyma, there is the potential for a persistent postoperative air leak. When hypoxia is refractory to optimal ventilation and standard methods cannot be the solution, alternative methods are needed.Selective lobar blockade is a novel approach that allows lobe(s) of independent lung and total dependent lung ventilation while the operated lobe is collapsed during thoracic surgery in patients without tolerance to OLV and pediatric VATS,which offers an attractive solution for targeted surgical access with preservation of ventilation of as much lung as possible. But the limitation to existing studies and case reports for selective lobar blockade is that they were all focused on children or patients who had previous contralateral lung resection or with diminished pulmonary function because of the affected surgical exposure.Oddly enough, a patient with relatively healthy lungs undergoing esophageal surgery or spine surgery could be more likely to suffer desaturation during OLV than a patient presenting for lung resection. In this study, selective lobar blockade is routinely performed in adult patients with normal spirometry during thoracic operations.Objective1.To study the effects on right-to-left shunt (Qs/Qt), arterial oxygenation and respiratory mechanics of left lower lobar blockade (LLB) by a Coopdech endobronchial blocker tube (BBT) in patients undergoing lower esophageal surgery.2.To search an ideal and optimal ventilatory maneuver for right middle and lower lobar blockade (RLB) during right-sided VATS.3.To design an endobronchial blocker which is special for selective lobar blockade.Methods1.The feasibility of selective lobar blockade for patients undergoing thoracotomy1.1 PatientsWith Ethics Committee approval and written informed consent,36 patients (age range,32-64 year; ASA physical statusⅠorⅡ;body mass index range,18-25 kg/m2) undergoing elective lower esophageal surgery via a left thoracotomy incision were enrolled in the study. Exclusion criteria included:asthma; active upper respiratory tract infection; known or suspected difficult airway; pulmonary infection; atelectasis; pulmonary function tests revealed a forced expiratory volume at one second<90% of predicted or forced vital capacity<90% of predicted; cardiac insufficiency; hypertension; hepatic inadequacy; nephrosis; anemia; or for any contraindication to the anaesthetic drugs described below.Patients were assigned randomly to two groups (n=18):A. right lung ventilation group (OLV group):Patients in this group were managed with the left-sided Broncho-Cath(?)DLT.B.left lower lobar blockade group (LLB group):Patients in this group were intubated with an 8.0-mm internal diameter standard single-lumen endotracheal tube, and LLB was then achieved with a 9 French BBT.1.2 General anaesthesia and tube positioningAnaesthesia was induced and maintained with target controlled infusing propofol. The BBT and DLT were placed by the same senior thoracic anaesthesiologist who was familiar with these devices before the study.In the OLV group, a flexible styletted DLT was accomplished via direct laryngoscopy according to a standardized protocol, and a fiberoptic bronchoscope (FOB) was then employed to confirm correct positioning of the tube, the upper surface of the endobronchial cuff was just visible below the tracheal carina.In the LLB group, the BBT was advanced through the blocker port of the joint connecter, and a FOB,which had been introduced through the fiberoptic port of the joint connecter, then guided the BBT into the left lower bronchus, the cuffed BBT was just visible inside the left lower lobe orifice and did not herniated to obstruct the left upper lobe.The patients were ventilated with a FiO2 of 0.6 through-out, ventilator settings were adjusted to a VT of 7-8 ml/kg, rate of 13-min-1 and I:E ratio 1:2 to maintain end-tidal CO2 (PETCO2) between 32-40 mmHg. Respiratory mechanics including peak inspiratory airway pressure (Ppeak), end-inspiratory airway pressure (Pplateau), dynamic lung compliance(Cdyn), VT, minute ventilation (MV), PETCO2, together with nasopharyngeal temperature were recorded. Ventilatory settings were kept constant during the study.After placement of central venous catheter and radial arterial catheter, and two-lung ventilation for 20min, the patients were placed in the right lateral decubitus position, the placement of the DLT or BBT cuff was reconfirmed. Then, the bronchial lumen of the DLT was clamped in the OLV group to perform right lung ventilation. The bronchial balloon of BBT was fully inflated in the LLB group, collapse of the left lower lobe was achieved while ventilation of the left upper lobe and right lung was maintained, and the BBT lumen was connected to wall suction to enhance the collapse of the left lower lobe.20 min later, the surgery began. Measuring patients' central venous pressure (CVP), blood lose and urine output to guide fluid administration. If upper or middle esophagus needed to be explored in the LLB group, BBT was withdrawn into left main bronchus by a FOB to perform temporary OLV, and BBT was advanced to the left lower bronchus after the exploration.The patients were extubated in the postanaesthesia care unit when they were fully awake to meet tracheal extubation criteria. Thereafter they were transferred to the postsurgery intensive care unit.1.3 Times for variables recording and blood gas analysis samplingT1:20 minutes after two-lung ventilation in supine positionT2:20 minutes after initiation of OLV or left lower lobar blockade in right lateral positionT3:total collapse of left lung or left lower lobe after the pleura was openedT4:20minutes after the chest was closed and switched to two-lung ventilationT5:in the first postoperative day while the patients were receiving oxygen via nasal catheter (2 L/min)1.4 Blood sample processing and variables recordingIntermittent arterial blood gas analysis was performed at T1 to T5,and mixed venous blood gas analysis was performed at T1 to T4.Qs/Qt and oxygenation index was calculated. SpO2, nasopharyngeal temperature, mean arterial blood pressure (MAP), heart rate (HR), Ppeak, Pplateau, Cdyn, VT, MV and PETCO2 were recorded at T1-T4. SpO2, axillary temperature, MAP, HR and CVP were recorded at T5. Once the pleura was opened, the effectiveness of lung collapse was evaluated by the surgeon who performed the surgery. The rank adopted to assess surgical exposure was excellent, fair or poor. A chest radiograph was taken in the first postoperative day to assess for any lobe collapse.The following variables were also recorded in all patients:1)time required to position these devices; 2) the number of intubating attempts;3)depth of insertion of BBT or DLT; 4) the number of malpositions after patients were in the lateral position; 5)the number of times that FOB was required in each patient; 6) duration of OLV or selective lobar blockade; 7) surgery duration; 8) volume of fluids, blood loss and urinary output; 9) postoperative length of stay.1.5 Statistical analysesDescriptive statistics(x±s) were used to summarize the continuous data, medians were used in categorical data. SPSS 13.0 statistical software package was used for all analyses.The Fisher's exact test and Mann-Whitney test were used to compare qualitative variables. The independent samples T test was used to compare continuous data between the two groups, while analysis of variance of repeated measures data was used to compare intragroup variables(PaO2, PvO2, PaCO2, pH, Qs/Qt, oxygenation index, hemoglobin, nasopharyngeal temperature, Ppeak, Pplateau, Cdyn, MV, VT, PETCO2) of different periods, and one-way analysis of variance was used for SpO2, MAP, HR and CVP of different periods, least-significant difference was used for multiple comparisons.P values<0.05 were considered to be statistically significant.2. Optimal ventilatory maneuver for selective lobar blockade during right-sided VATS2.1 PatientsWith Ethics Committee approval and written informed consent,38 patients (age range,27-64 year; ASA physical statusⅠorⅡ;height range, male≥165cm, female≥160cm) undergoing elective right middle or lower lobe wedge resection via right-sided VATS were enrolled in the study. Exclusion criteria:same as the first stage together with CT or chest radiograph revealed that the lobar mass was malignant tumor. Patients were assigned randomly to two groups (n=19):A. left lung ventilation group (OLV group):Patients in this group were managed with the left-sided Broncho-Cath(?)DLT.B.right middle and lower lobar blockade group (RLB group):Patients in this group were intubated with an 8.0-mm internal diameter standard single-lumen endotracheal tube, and RLB was then achieved with a 9 French BBT.2.2 General anaesthesia and tube positioningAnaesthesia was induced and maintained with target controlled infusing propofol.In the RLB group, the BBT was advanced into the right middle bronchus with the guidance of a FOB,the cuffed BBT was just visible under the right upper lobe orifice. The intubation of DLT, placement of central venous catheter and radial arterial catheter, fluid administration, airway and postoperative management were similar to the first stage.The patients were ventilated with a FiO2 of 0.6 through-out, ventilator settings were adjusted to a VT of 8 ml/kg, rate of 12-min-1 and I:E ratio 1:2.After two-lung ventilation for 20min, the patients were placed in the left lateral decubitus position, a lower VT of 6 ml/kg and a rapid rate of 14-16-min-1 were achieved.Then, the bronchial lumen of the DLT was clamped in the OLV group to perform left lung ventilation. The bronchial balloon of BBT was fully inflated in the RLB group, collapse of the right middle and lower lobes was achieved while ventilation of the right upper lobe and left lung was maintained, and the BBT lumen was connected to wall suction to enhance the collapse of the right middle and lower lobes.At the end of the surgery, ventilator settings were adjusted to a VT of 7-8 ml/kg, rate of 12-13·min-1 while switched to two-lung ventilation.If lobar bronchi needed to be explored in the RLB group, BBT was withdrawn into right main bronchus by a FOB to perform temporary OLV, and BBT was advanced to the right middle bronchus after the exploration.2.3 Times for variables recording and blood gas analysis samplingT1:20 minutes after two-lung ventilation in supine positionT2:20 minutes after initiation of OLV or right middle and lower lobar blockade in left lateral positionT3:total collapse of right lung or right middle and lower lobes after the pleura was openedT4:20minutes after the chest was closed and switched to two-lung ventilationT5:in the first postoperative day while the patients were receiving oxygen via nasal catheter (2 L/min)2.4 Blood sample processing, variables recording and statistical analyses Identical with the first stage.3.Design of Ye's double cuffs endobronchial blocker tubeYe's double cuffs endobronchial blocker tube is designed for patients undergoing selective lobar blockade or OLV, the additional guide wire can be used to facilitate the tube placement. The left-sided tube and the right-sided tube are manufactured respectively, which are different between the shape of the cuffs and the angled tip. The upper balloon of the blocker tube is placed into the main bronchus, just visible under the tracheal carina, the lower balloon of it is stayed inside the orifice of the lobar bronchi, e.g. left lower lobar bronchus, right upper lobe orifice.Results1.The feasibility of selective lobar blockade for patients undergoingthoracotomy1.1 Demographic dataThe two groups were comparable in terms of age, height, weight, male/female ratio, procedure duration, OLV or LLB duration, dose of agents, volume of fluid, blood loss, and urinary output, and MAP, HR, CVP during the study (P>0.05).Patients in the LLB group needed longer time to position BBT and a significantly greater number of times that FOB was used in total, depth of insertion of BBT was deeper than DLT (P<0.05 or 0.01).The number of intubating attempts and malpositions shown no difference and the intrathoracic exposure was generally excellent in both groups (P>0.05).Cases of rank of excellent collapse were 12 in LLB group vs 14 in OLV group, cases of rank of fair were 6 in LLB group vs 4 in OLV group.It was necessary to expose upper or middle esophagus in 3 patients of the LLB group, patients were perform OLV 11.5±1.8 minutes.1.2 Data of blood gas analyses and SpO21.2.1 Intergroup comparisonThere were no differences between groups with respect to arterial blood gas measurements in T1 and T4. Selective left lower lobar collapse improved PaO2 and PvO2 values, oxygenation index and SpO2, decreased Qs/Qt in T2 and T3 (P<0.05 or 0.01).PaCO2, pH, hemoglobin, and nasopharyngeal temperature were within normal limits in all cases during the study.1.2.2 Intragroup comparisonInitiating OLV or LLB deteriorated PaO2 and PvO2 values, oxygenation index, SpO2 and increased Qs/Qt significantly in both groups (P<0.05 or 0.01).Qs/Qt in T4 was similar to that in Tl in both groups.PaO2 values, oxygenation index in T4 recovered to values of those obtained in T1 only in the LLB group.1.3 Data of respiratory mechanics1.3.1 Intergroup comparisonThere were no differences between groups with respect to measurements of respiratory mechanics in T1.Selective left lower lobar collapse improved Cdyn (P< 0.01),decreased Ppeak and Pplateau (P<0.05) in T2 and T3.No differences were found among VT, MV and PETCO2 between groups during the study (P>0.05). 1.3.2 Intragroup comparisonInitiating OLV or LLB with invariant ventilatory settings increased Ppeak and Pplateau, decreased Cdyn, VT, MV, PETCO2 significantly in both groups (P<0.05 or 0.01).But all changes recovered to values of those obtained in T1 at T4 (P>0.05).1.4 Postoperative dataIn the first postoperative day, PaO2 values, oxygenation index in the LLB group was significant higher than that in the OLV group.Since there were 2 patients in the OLV group revealed left lower lobe atelectasis by chest radiograph, postoperative length of stay in this group was longer than that of LLB group (P<0.01).2. Optimal ventilatory maneuver for selective lobar blockade during right-sided VATS2.1 Demographic dataThe two groups were comparable in terms of age, height, weight, male/female ratio, procedure duration, OLV or RLB duration, dose of agents, volume of fluid, blood loss, and urinary output, time required to position the tubes and MAP, HR, CVP during the study (P>0.05).A significantly greater number of times that FOB was used in the patients of RLB group and depth of insertion of BBT was deeper than DLT (P<0.01).The number of intubating attempts and malpositions shown no difference and the surgical exposure was uniformly good between the two groups (P>0.05). Cases of rank of excellent collapse were 13 in LLB group vs 15 in OLV group, cases of rank of fair were 6 in LLB group vs 4 in OLV group. Lobar bronchi needed to be explored in 16 patients of the RLB group, OLV duration was 15.2±2.9minutes, and total collapse of right upper lobe took 6.0±1.1 minutes.2.2 Data of blood gas analyses and SpO22.2.1 Intergroup comparisonThere were no differences between groups with respect to arterial blood gas measurements in T1 and T4. Selective right middle and lower lobar collapse improved PaO2 and PvO2 values, oxygenation index and SpO2 in T2 and T3, decreased Qs/Qt in T2, T3 and T4 (P<0.05 or 0.01).PaCO2, pH, hemoglobin, and nasopharyngeal temperature were within normal limits in all cases during the study.2.2.2 Intragroup comparisonInitiating OLV or RLB impaired PaO2 and PvO2 values, oxygenation index, SpO2 and increased Qs/Qt significantly in both groups (P<0.05 or 0.01),but Qs/Qt in T2 of the RLB group wasn't differ from T1.Qs/Qt in T4 was similar to that in T1 in both groups.PaO2 values, oxygenation index in T4 recovered to values of those obtained in T1 only in the LLB group.2.3 Data of respiratory mechanics2.3.1 Intergroup comparisonThere were no differences between groups with respect to measurements of respiratory mechanics in T1.Selective right middle and lower lobar collapse improved Cdyn, MV and VT, decreased Ppeak and Pplateau in T2 and T3 (P<0.05 or 0.01).Ppeak and Pplateau in the RLB group were still lower than those in the OLV group in T4 (P<0.05). No differences were found among PETCO2 between groups during the study (P>0.05).2.3.2 Intragroup comparisonInitiating OLV or RLB with lower VT still increased Ppeak and Pplateau, and Cdyn, VT, MV, PETCO2 decreased significantly in both groups (P<0.05 or 0.01).But all changes recovered to values of those obtained in T1 while switched to two lung ventilation (P>0.05).2.4 Postoperative dataIn the first postoperative day, a higher PaO2 values with a better oxygenation index was shown in the RLB group (P<0.05 or 0.01).No lobe atelectasis or persistent postoperative air leak was detected, postoperative length of stay was similar in both groups.Conclusions1.Left lower lobar blockade delivers better perioperative arterial oxygenation and respiratory mechanics, lower right-to-left shunt during lower esophageal surgery via left thoracotomy, it can maintain adequate gas exchange, provent from hypoxia and provide a better postoperative recovery for adult patients with normal spirometry.2.Left lower lobar blockade provides similar procedure duration and quiet surgical field with one-lung ventilation during lower esophageal surgery via left thoracotomy, and can be routinely performed in a series of thoracic procedures which are relative indications for one-lung ventilation.3.The combination of right middle and lower lobar blockade with a lower tidal volumes and more rapid respiratory rates and temporary one-lung ventilation is an ideal ventilatory maneuver for management of video-assisted thoracic surgery to achieve good surgical exposure during right middle or lower lobe wedge resection via right-sided video-assisted thoracic surgery, which improves perioperative arterial oxygenation. This method can be introduced in these sorts of procedures safely.4.The above ventilatory strategy can ameliorate hypoxia caused by one-lung ventilation.5.The clinical application of Ye's double cuffs endobronchial blocker tube might integrate one-lung ventilation with selective lobar blockade and give security against the complication of this ventilatory strategy.