Speed of collapse of the non-ventilated lung during single-lung ventilation for thoracoscopic surgery: the effect of transient increases in pleural pressure on the venting of gas from the non-ventilated lung

[Preliminary Study of CT Three-dimensional Reconstruction Combined with Ground Glass Nodules of Natural Lung Collapse in Thoracoscopic Pulmonary Segmental Resection]

BACKGROUND

Computed tomography (CT) three-dimensional reconstruction technology is increasingly used in preoperative planning of patients with ground glass nodule (GGN), but how to accurately locate the nodule and ensure the safe resection edge is still a difficult problem for clinicians. The purpose of this study was to investigate the accuracy, convenience and safety of CT three-dimensional reconstruction combined with intraoperative natural collapse localization in total thoracoscopic segmental pneumonectomy.

METHODS

A total of 45 patients with radiographic findings of pulmonary GGN admitted from July 2019 to December 2019 were selected as the study group. All patients received thin-slice CT scan and underwent preoperative three-dimensional reconstruction. After anesthesia, the small thoracic operation opening and the airway of the patients were quickly opened, and the lung was rapidly and naturally collapsed by pressure difference. GGN were positioned according to the natural marker line, and marked with 3-0 prolene line. After specimen removal, the distance between the GGN and the suture mark, the distance between the GGN and the incision margin were measured, and the incision margin was routinely examined. The general clinical data, pathological data and postoperative complications were counted and compared with 45 consecutive patients who were located with hookwire positioning needle in the same period.

RESULTS

The average localization time of non-invasive GGN with natural lung collapse during operation was 6.9 min, and the localization accuracy was 90.6%. There were 2 cases of extensive pleural adhesion and 1 case of emphysema. Postoperative pathology was confirmed as lung adenocarcinoma, and the examination of incision margin was negative. No GGNs were scanned again after surgery, and the precise resection rate of lung segment was 100.0%.

CONCLUSIONS

CT three-dimensional reconstruction combined with GGN localization of natural lung collapse during operation can shorten the time of searching for GGN during operation and guarantee the safety of the incision margin. It is a more economical and convenient localization method and makes pulmonary segment resection more accurate.

Stapling of an endobronchial suction tube with the bronchus during robot-assisted right lower lobectomy: a case report

Background

Troubleshooting intraoperative complications requires careful management, and the safest technique should be chosen. We recently experienced a unique intraoperative bronchial complication during pulmonary lobectomy in robot-assisted thoracic surgery (RATS). There is no consensus on whether to continue RATS or convert to a more familiar technique, such as video-assisted thoracic surgery (VATS) or thoracotomy, for intraoperative complications that occur during RATS, and the decision should be determined individually.

Case presentation

A 74-year-old woman with primary lung adenocarcinoma (clinical stage IA2) underwent robot-assisted right lower lobectomy under one-lung ventilation and CO₂ insufflation. Intraoperatively, the anesthesiologist placed the endobronchial suction tube in the right bronchus with intention of maintaining the right lung collapse, which was simultaneously stapled with the right lower bronchus during the right lower lobe bronchial closure using a robotic stapler. During robot-assisted manipulation, we removed the staples involved with the suction tube, one by one, using robotic-arm forceps and sutured the partially opened stump. Subsequently, the bronchial stump was covered with a pedicled pericardial fat pad. The postoperative course was uneventful, and the patient developed no complications when followed up 8 months after discharge. Hence, we could rectify this intraoperative bronchial complication using a robot-assisted technique and avoid conversion to VATS or thoracotomy.

Conclusion

The precise manipulation techniques in RATS contributed to facilitate the successful execution of surgical procedures, such as staple removal and re-suturing of the bronchial stump and may be a useful as a method for such troubleshooting such intraoperative complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40792-021-01278-5.

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.

Combination of nitrous oxide and the modified inflation-deflation method for identifying the intersegmental plane in segmentectomy: A randomized controlled trial

Background

During thoracoscopic segmentectomy, accurately and rapidly identifying the intersegmental plane (ISP) is of great importance. This study aimed to investigate the effect and safety of a nitrous oxide (N₂O)/oxygen (O₂) inspired mixture on the appearance time of the ISP (T_ISP) via the modified inflation‐deflation method.

Methods

A total of 65 participants who underwent segmentectomy were randomized into three groups: 75% N₂O (n = 24), 50% N₂O (n = 23) or 0% N₂O (n = 18). The 75% N₂O group received a gas mixture of N₂O/O₂ (Fio₂ = 0.25), the 50% N₂O group received N₂O/O₂ (Fio₂ = 0.5), and the 0% N₂O group received 100% oxygen during lung expansion. The appearance time of satisfactory and ideal planes was recorded. Furthermore, arterial blood gas at breathing room air, one‐lung ventilation (OLV) before lung expansion, 5 and 15 min after lung expansion were also recorded.

Results

T_ISP was significantly shorter in the 75% N₂O group (320.2 ± 65.9 s) compared with that of the 50% N₂O group (552.4 ± 88.9 s, p < 0.001) and the 0% N₂O group (968.3 ± 85.5 s, p < 0.001), while the 50% N₂O group was shorter than that of the 0% N₂O group (p < 0.001). Arterial oxygenation was significantly improved in the 0% N₂O group only after lung expansion, before which there were no differences in mean PaO₂ values among groups.

Conclusions

The use of N₂O in the inspired gas mixture during lung expansion is an applicable strategy to rapidly identify the ISP via the modified inflation‐deflation method without any adverse effect on OLV related arterial oxygenation during segmentectomy.

[Translobar Phenomenon of Pulmonary Veins and Its Clinical Significance in Lobectomy]

背景与目的

肺叶切除术是早期肺癌的主要治疗方式，然而肺部解剖变异繁多，尤其是部分肺静脉会脱离正常解剖位置，甚至跨越肺叶边界进入相邻肺叶，这增加了手术的难度和风险。本研究旨在全面分析肺跨叶静脉的类型和发生频率，并进一步探究其在肺叶切除术中的临床意义。

方法

纳入南京医科大学第一附属医院2018年12月-2019年11月期间行肺部手术的患者916例，筛选出术前行胸部增强计算机断层扫描（computed tomography, CT）检查的病例310例，应用这些患者的胸部增强CT和三维CT支气管血管成像（three-dimensional computed tomography bronchography and angiography, 3D-CTBA）对跨叶静脉的类型及频率进行分析。进一步从916例手术病例中筛选出行肺叶切除术且手术区域涉及到跨叶静脉的病例共48例（切断组36例，保留组12例），通过手术录像观察两种不同的处理方式对余肺叶的影响。

结果

共发现26种肺跨叶静脉模式，总发生率为82.26%，右肺远大于左肺（80.65% vs 11.94%）。右肺中主要类型（频率 > 5%）包括：中间支气管后方汇入下肺静脉的VX2（5.48%）、汇集上、下叶静脉属支的叶间静脉V³b（58.39%）、水平裂内汇入V²（13.23%）或V³（12.58%）的VX⁴、中叶支气管下方汇入左心房的VX⁴（8.71%）或VX⁵（7.42%）、肺裂内汇入V²的VX⁶（29.68%）；左肺中主要类型为整支上肺静脉汇入下肺静脉形成共干的左肺静脉（9.36%），其中共干长度 > 1 cm的占4.84%。观察手术录像发现：与保留组相比，切断组中患者其余肺叶的血液循环功能受到影响（表现为受影响区域停止通气后长时间无法萎陷），术后咯血（13.89% vs 0.00%）和肺漏气（19.44% vs 8.33%）发生率增加，术后住院时间[(4.72±1.86) d vs (3.92±1.62) d]较长，术后3 d引流量[(705.42±265.02) mL vs (604.92±229.64) mL]较多，但差异无统计学意义（P > 0.05）。

结论

肺静脉跨叶现象种类繁多，且部分类型发生率较高。然而大部分跨叶静脉在手术中被忽视，这可能对手术安全和患者术后恢复产生不利影响。

The fraction of nitrous oxide in oxygen for facilitating lung collapse during one-lung ventilation with double lumen tube

BACKGROUND

The ideal fraction of nitrous oxide (N₂O) in oxygen (O₂) for rapid lung collapse remains unclear. Accordingly, this prospective trial aimed to determine the 50% effective concentration (EC₅₀) and 95% effective concentration (EC₉₅) of N₂O in O₂ for rapid lung collapse.

METHODS

This study included 38 consecutive patients undergoing video-assisted thoracoscopic surgery (VATS). The lung collapse score (LCS) of each patient during one-lung ventilation was evaluated by the same surgeon. The first patient received 30% N₂O in O₂, and the subsequent N₂O fraction in O₂ was determined by the LCS of the previous patient using the Dixon up-and-down method. The testing interval was set at 10%, and the lowest concentration was 10% (10, 20, 30, 40%, or 50%). The EC₅₀ and EC₉₅ of N₂O in O₂ for rapid lung collapse were analyzed using a probit test.

RESULTS

According to the up-and-down method, the N₂O fraction in O₂ at which all patients exhibited successful lung collapse was 50%. The EC₅₀ and EC₉₅ of N₂O in O₂ for rapid lung collapse were 27.7% (95% confidence interval 19.9-35.7%) and 48.7% (95% confidence interval 39.0-96.3%), respectively.

CONCLUSIONS

In patients undergoing VATS, the EC₅₀ and EC₉₅ of N₂O in O₂ for rapid lung collapse were 27.7 and 48.7%, respectively.

TRIAL REGISTRATION

http://www.chictr.org/cn/ Identifier ChiCTR19 00021474 , registered on 22 February 2019.

The disconnection technique with the use of a bronchial blocker for improving nonventilated lung collapse in video-assisted thoracoscopic surgery

Background

Methods

Results

Conclusions

Volume of tidal gas movement in the nonventilated lung during one-lung ventilation and its relevant factors

Background

The passive ventilation of nonventilated lung results in tidal gas movement (TGM) and thus affects lung collapse. The present study aimed to measure the volume of TGM and to analyse the relevant factors of the TGM index (TGM/body surface area).

Methods

One hundred eight patients scheduled for elective thoracoscopic surgeries were enrolled. Lung isolation was achieved with a double-lumen endobronchial tube (DLT). The paediatric spirometry sensor was connected to the double-lumen connector of the nonventilated lung to measure the volume of TGM during one-lung ventilation (OLV) in the lateral position. The TGM index was calculated. The multiple linear regression was analysed using the TGM index as the dependent variables. Independent variables were also recorded: 1) age, sex, body mass index (BMI); 2) forced vital capacity (FVC), FEV₁/FVC, minute ventilation volume (MVV); 3) dynamic lung compliance (Cdyn) and peak inspiratory pressure (PIP) during dual lung ventilation; 4) the side of OLV; and 5) whether lung puncture for localization of the pulmonary nodule was performed on the day of surgery. The oxygen concentration in the nonventilated lung was measured at 5 min after OLV, and its correlation with the TGM index was analysed.

Results

The volume of TGM in the nonventilated lung during OLV was 78 [37] mL. The TGM index was 45 [20] mL/m² and was negatively correlated with the oxygen concentration in the nonventilated lung at 5 min after OLV. The multiple linear regression model for the TGM index was deduced as follows: TGM index (mL/m²) = C + 12.770 × a − 3.987 × b-1.237 × c-2.664 × d, where C is a constant 95.621 mL/m², a is 1 for males and 0 for females, b is 1 for right OLV and 0 for left OLV, c is BMI (kg/m²), and d is PIP (cmH₂O).

Conclusions

The TGM index is negatively correlated with the oxygen concentration of the nonventilated lung at 5 min after OLV. Sex, side of OLV, BMI and PIP are independently correlated with the TGM index.

Trial registration

This study was registered at ChiCTR (www.chictr.org.cn, ChiCTR1900024220) on July 1, 2019.

Preemptive one lung ventilation enhances lung collapse during thoracoscopic surgery: A randomized controlled trial

In routine practice, one lung ventilation (OLV) is initiated upon pleural opening. We conducted a randomized controlled trial to compare lung collapse after preemptive OLV versus conventional OLV in thoracoscopic surgery. A total of 67 patients were enrolled (34 with conventional OLV; 33 with preemptive OLV). Preemptive OLV was conducted by closing the DLT lumen to the non‐ventilated lung immediately upon assuming the lateral position with the distal port closed to the atmosphere until pleural opening (>6 minutes in all cases). Lung collapse was assessed at 1, 5, 10, 20, 30 and 40 minutes after pleural opening using a 10‐point rating scale (10: complete collapse). The primary end point was the duration from pleural opening to satisfactory lung collapse (score of 8). Secondary end points included PaO₂ and hypoxemia. The duration from pleural opening to satisfactory lung collapse was shorter in the preemptive OLV group (9.1 ± 1.2 vs. 14.1 ± 4.7 minutes, P < 0.01). PaO₂ was comparable between the two groups prior to anesthetic induction (T0), and 20 (T2), 40 minutes (T3) after pleural incision, but was lower in the preemptive OLV group at zero minutes after pleural incision (T1) (457.5 ± 19.0 vs. 483.1 ± 18.1 mmHg, P < 0.01). No patients in either group developed hypoxemia. In summary, preemptive OLV expedites lung collapse during thoracoscopic surgery with minimal safety concern.

Arterial Oxygen Desaturation during only one of two Similar Thoracoscopic Procedures on the Same Patient

The present report describes two similar thoracoscopic procedures performed on the same 81-year-old male patient. Because acute hypoxia had developed during one-lung ventilation on the first occasion, serial blood gases were taken during the second. Also, whereas on the first occasion the non-ventilated lung had been left open to air when one-lung ventilation was initiated, on the second it was connected to an ambient pressure oxygen source with the object of theoretically enabling apnoeic oxygenation during lung collapse. It is argued that this fundamental difference in anaesthetic practice may have contributed to the improved oxygenation that was recorded during the second thoracoscopy.

The Theoretical Basis for Using Apnoeic Oxygenation via the Non-ventilated Lung during One-lung Ventilation to Delay the Onset of Arterial Hypoxaemia

At the time one-lung ventilation is initiated, nitrogen from the atmosphere may enter the non-ventilated lung via a double-lumen tube connector that has been left open to air, even momentarily. Ongoing oxygen uptake from the non-ventilated lung raises the partial pressure of nitrogen. This should lead to activation of hypoxic pulmonary vasoconstriction and a reduction in intra-pulmonary shunting. However, in spite of this, some patients still become hypoxaemic. In such cases, it may be advantageous to have excluded nitrogen from the non-ventilated lung by connecting it to an oxygen source at ambient pressure. Ongoing apnoeic oxygenation, while the airways are patent, and as the lung collapses, should delay the onset of arterial desaturation. In this paper we review the theoretical basis for apnoeic oxygenation during one-lung ventilation, and in particular on oxygen uptake by the non-ventilated lung prior to and during its subsequent collapse.

Bronchial suction does not facilitate lung collapse when using a double-lumen tube during video-assisted thoracoscopic surgery: a randomized controlled trial

Background

Bronchial suction through the lumen of a bronchial blocker has been reported to accelerate lung collapse. The aim of the current study was to examine whether bronchial suction could also facilitate lung collapse when using a double-lumen tube (DLT).

Methods

Eighty patients scheduled for elective video-assisted thoracoscopic surgery for lung cancer using a DLT for one-lung ventilation (OLV) were randomised into an arm that received bronchial suction and an arm that underwent spontaneous collapse (n=40 per arm). For bronchial suction, a pressure of -30 cmH₂O was applied to the lumen of the non-ventilated lung during the first minute of OLV. The primary endpoint was the degree of lung collapse at 10 min after the start of OLV, assessed on a 10-point visual analogue scale (0: fully inflated; 10: complete collapse). Secondary outcomes included lung collapse at 1 and 5 min after the start of OLV, as well as occurrence of intraoperative hypoxemia.

Results

Median (interquartile range) lung collapse scores at 10 min were statistically greater in the bronchial suction arm than in the spontaneous collapse arm [9.0 (9.0-9.0) vs. 8.5 (8.0-9.0); P=0.004]. Lung collapse was also statistically greater in the bronchial suction arm at 5 min [8.0 (7.0-8.0) vs. 7.0 (6.25-7.0) min; P=0.002] and 1 min [4.0 (4.0-5.0) vs. 2.0 (2.0-2.0) min; P<0.001]. None of the patients experienced intraoperative hypoxemia and operative complications.

Conclusions

Bronchial suction resulted in statistically greater but not clinically meaningful lung collapse when using a DLT. However, greater degree of lung collapse at 1-min could be helpful in reducing accidental injuries.

Two-minute disconnection technique with a double-lumen tube to speed the collapse of the non-ventilated lung for one-lung ventilation in thoracoscopic surgery

Background

Thoracic surgery requires the effective collapse of the non-ventilated lung. In the majority of cases, we accomplished, accelerated lung collapse using a double-lumen tube (DLT). We hypothesized that using the two-minute disconnection technique with a DLT would improve lung collapse during subsequent one-lung ventilation.

Methods

Fifty patients undergoing thoracoscopic surgery with physical classification I or II according to the American Society of Anesthesiologists were randomly divided into two groups for respiratory management of one-lung ventilation (OLV). In group N, OLV was initiated after the DLT was disconnected for 2 min; the initiation time began when the surgeon made the skin incision. In group C, OLV was initiated when the surgeon commenced the skin incision and scored the quality of lung collapse (using a four-point ordinal scale). The surgeon’s satisfaction or comfort with the surgical conditions was assessed using a visual analogue scale. rSO₂ level, mean arterial pressure, pulse oxygen saturation, arterial blood gas analysis, intraoperative hypoxaemia, intraoperative use of CPAP during OLV, and awakening time were determined in patients at the following time points: while inhaling air (T₀), after anaesthesia induction andinhaling 100% oxygen in the supine position under double lung ventilation for five mins (T₁), at two mins after skin incision (T₂), at ten mins after skin incision (T₃), and after the lung recruitment manoeuvres and inhaling 50% oxygen for five mins (T₄).

Results

The two-minute disconnection technique was associated with a significantly shorter time to total lung collapse compared to that of the conventional OLV ventilation method (15 mins vs 22 mins, respectively; P < 0.001), and the overall surgeon’s satisfaction was higher (9 vs 7, respectively; P < 0.001). At T₂, the PaCO₂, left rSO₂ and right rSO₂ were higher in group N than in group C. There were no statistically significant differences between the incidence of intraoperative hypoxaemia and intraoperative use of CPAP during OLV (10% vs 5%, respectively; P = 1.000), duration of awakening (18 mins vs 19 mins, respectively; P = 0.616).

Conclusions

A two-minute disconnection technique using a double-lumen tube was used to speed the collapse of the non-ventilated lung during one-lung ventilation for thoracoscopic surgery. The surgeon was satisfied with the surgical conditions.

Trial registration

Chinese Clinical Trial Registry number, ChiCTR-IPR-17010352. Registered on Jan, 7, 2017.

Preoxygenation using invasive ventilator in volume control mode in patients with emergency intubation can shorten the time of preoxygenation and improve the quality of preoxygenation: A retrospective study

Preoxygenation can rapidly improve oxygenation and enhance the security of endotracheal intubation, so it is very essential before endotracheal intubation. The conventional preoxygenation method self-inflating bag (SIB) is not very effective in case of emergency. So our study aims to find a more effective method of preoxygenation in a critical situation.We retrospectively analyzed data of 105 patients in this study. A total of 49 patients with preoxygenation with invasive ventilator in volume control mode (VCM) and 56 patients with preoxygenation with SIB were included. No significant differences were detected in the baseline data of the 2 groups (P > 0.05). Time of preoxygenation (95%) was 174 (168-180) seconds in group VCM and 205 (199-212) seconds in group SIB (P < 0.05), and multifactor linear regression showed that its main risk factors were the methods of preoxygenation and PO2 before preoxygenation (P < 0.05). Immediate SPO2 after preoxygenation was 91 (89-92)% in group VCM and 85 (83-86)% in group SIB (P < 0.05). Total time of preoxygenation and intubation was 266 (252-280) seconds in group VCM and 318 (298-338) seconds in group SIB (P < 0.05). The 24-hour and overall survival rate in group SIB were lower than in group VCM (P > 0.05). Cox regression showed that SaO2 at 5 minutes after intubation was the major risk factor for the survival rate.Invasive ventilator with volume control mode can shorten the time of preoxygenation and improve the quality of preoxygenation in patients with emergency intubation and may be a better method of preoxygenation in a critical situation.

Cardiovascular collapse caused by carbon dioxide insufflation during one-lung anaesthesia for thoracoscopic dorsal sympathectomy

Carbon dioxide insufflation into the pleural space during one-lung anaesthesia for thoracoscopic surgery is used in some centres to improve surgical access, even though this practice has been associated with well-described cardiovascular compromise. The present report is of a 35-year-old woman undergoing thoracoscopic left dorsal sympathectomy for hyperhidrosis. During one-lung anaesthesia the insufflation of carbon dioxide into the non-ventilated hemithorax for approximately 60 seconds, using a pressure-limited gas inflow, was accompanied by profound bradycardia and hypotension that resolved promptly with the release of the gas. Possible mechanisms for the cardiovascular collapse are discussed, and the role of carbon dioxide insufflation as a means of expediting lung collapse for procedures performed using single-lung ventilation is questioned.

Speed of collapse of the non-ventilated lung during one-lung anaesthesia: the effects of the use of nitrous oxide in sheep

By enhancing gaseous uptake from the non-ventilated lung during procedures performed thoracoscopically, the rapid diffusion properties of nitrous oxide would be expected to speed lung collapse and so facilitate surgery. To assess the effect of nitrous oxide on the speed of absorptive lung collapse, a study was conducted using 11 anaesthetised sheep. Speed of collapse was assessed in an indirect manner by recording the time required in a closed-chest situation for the airway pressure distal to a single lung airway occlusion to decrease to - 1.0 kPa. The influence of nitrous oxide was assessed by comparing the time taken for this decrease in airway pressure when the animal was being mechanically ventilated with 50% nitrous oxide in oxygen with the time taken when using 100% oxygen. In all assessments, it was found that the decrease in airway pressure to - 1.0 kPa occurred in a shorter time when nitrous oxide was used. The findings lend support to the hypothesis that during thoracoscopic surgery, mechanical lung ventilation with an oxygen/nitrous oxide mixture will increase the rate of gaseous uptake from the non-ventilated lung and so hasten its absorptive collapse.