Hemodynamic effects of carbon dioxide insufflation during thoracoscopy

Perioperative cardiovascular pathophysiology in patients undergoing lung resection surgery: a narrative review

Although thoracic surgery is understood to confer a high risk of postoperative respiratory complications, the substantial haemodynamic challenges posed are less well appreciated. This review highlights the influence of cardiovascular comorbidity on outcome, reviews the complex pathophysiological changes inherent in one-lung ventilation and lung resection, and examines their influence on cardiovascular complications and postoperative functional limitation. There is now good evidence for the presence of right ventricular dysfunction postoperatively, a finding that persists to at least 3 months. This dysfunction results from increased right ventricular afterload occurring both intraoperatively and persisting postoperatively. Although many patients adapt well, those with reduced right ventricular contractile reserve and reduced pulmonary vascular flow reserve might struggle. Postoperative right ventricular dysfunction has been implicated in the aetiology of postoperative atrial fibrillation and perioperative myocardial injury, both common cardiovascular complications which are increasingly being appreciated to have impact long into the postoperative period. In response to the physiological demands of critical illness or exercise, contractile reserve, flow reserve, or both can be overwhelmed resulting in acute decompensation or impaired long-term functional capacity. Aiding adaptation to the unique perioperative physiology seen in patients undergoing thoracic surgery could provide a novel therapeutic avenue to prevent cardiovascular complications and improve long-term functional capacity after surgery.

Recent Advances in Videolaryngoscopy for One-Lung Ventilation in Thoracic Anesthesia: A Narrative Review

Since their advent, videolaryngoscopes have played an important role in various types of airway management. Lung isolation techniques are often required for thoracic surgery to achieve one-lung ventilation with a double-lumen tube (DLT) or bronchial blocker (BB). In the case of difficult airways, one-lung ventilation is extremely challenging. The purpose of this review is to identify the roles of videolaryngoscopes in thoracic airway management, including normal and difficult airways. Extensive literature related to videolaryngoscopy and one-lung ventilation was analyzed. We summarized videolaryngoscope-guided DLT intubation techniques and discussed the roles of videolaryngoscopy in DLT intubation in normal airways by comparison with direct laryngoscopy. The different types of videolaryngoscopes for DLT intubation are also compared. In addition, we highlighted several strategies to achieve one-lung ventilation in difficult airways using videolaryngoscopes. A non-channeled or channeled videolaryngoscope is suitable for DLT intubation. It can improve glottis exposure and increase the success rate at the first attempt, but it has no advantage in saving intubation time and increases the incidence of DLT mispositioning. Thus, it is not considered as the first choice for patients with anticipated normal airways. Current evidence did not indicate the superiority of any videolaryngoscope to another for DLT intubation. The choice of videolaryngoscope is based on individual experience, preference, and availability. For patients with difficult airways, videolaryngoscope-guided DLT intubation is a primary and effective method. In case of failure, videolaryngoscope-guided single-lumen tube (SLT) intubation can often be achieved or combined with the aid of fibreoptic bronchoscopy. Placement of a DLT over an airway exchange catheter, inserting a BB via an SLT, or capnothorax can be selected for lung isolation.

Positive Intrapleural Pressure with Carbon Dioxide May Limit Intraoperative Pulmonary Arterial Bleeding: Verification by Animal Model

PURPOSE

Intraoperative complications, especially unexpected bleeding, are of great concern in the safety of thoracoscopic surgery. We investigated the hemostatic efficacy and safety of positive intrapleural pressure (PIP) with carbon dioxide insufflation by assessing the amount of blood loss in a pulmonary arterial hemorrhage model.

METHODS

An ex vivo experimental model of saline flow into a swine vessel was created in a container simulating a chest cavity. From the results, in vivo experiments (swine model) were conducted to compare the pulmonary arterial bleeding volume while applying PIP.

RESULTS

In the ex vivo experiment, regardless of the incision type, the outflow volumes did not significantly differ at flow pressures of 20, 30, and 40 mmHg. At each flow pressure, the outflow volumes at 10, 15, and 20 mmHg of positive pressure in the container were significantly smaller than those of the control (p = 0.027, p = 0.002, and p = 0.005, respectively). Similarly, the in vivo experiments showed that bleeding decreased as intrapleural pressure increased (slope = -0.22, F = 55.13, p <0.0001).

CONCLUSION

It may be possible to temporarily suppress pulmonary arterial bleeding by increasing the intrapleural pressure to 10 to 20 mmHg using carbon dioxide insufflation. This method may be an adjunctive hemostatic maneuver for intraoperative bleeding.

Anesthesia for robotic thoracic surgery

The management of the robotic thoracic surgical patient requires the knowledge of minimally invasive surgery techniques involving the chest. Over the past decade, robotic-assisted thoracic surgery has grown, and, in the future, it will take an important place in the treatment of complex thoracic pathologies. The enhanced dexterity and three-dimensional visualization make it possible to do this in the small space of the thoracic cavity. Familiarity with the robotic surgical system by the anesthesiologists is mandatory. Management of a long period of one-lung ventilation with a left-sided double-lumen endotracheal tube or an independent bronchial blocker is required, along with flexible fiberoptic bronchoscopy techniques (best continuous monitoring). Correct patient positioning and prevention of complications such as eye or nerve or crashing injuries while the robotic system is used is mandatory. Recognition of the hemodynamic effects of carbon dioxide during insufflation in the chest is required. Cost is higher and outcome is not yet demonstrated to be better as compared to video-assisted thoracic surgery. The possibility for conversion to open thoracotomy should also be kept in mind. Teamwork is mandatory, as well as good communication between all the actors of the operating theatre.

Ultrasonography in the diagnosis of lung adhesion before surgery

Background The presence of pleural adhesions may render video-assisted thoracoscopic surgery difficult or impossible. The aim of this study was to assess the value of chest ultrasonography in the detection of pleural adhesions prior to thoracotomy. Methods Between 2013 and 2014, 42 consecutive patients undergoing thoracotomies (including video-assisted thoracicsurgery) were evaluated with chest ultrasonography. These patients underwent a preoperative ultrasonic examination of the chestwall using a 7.5-10-MHz linear ultrasound probe at 7 points along the chest wall. We measured the movement of the visceral pleuralslide. Results In the upper thoracic wall,ultrasonography demonstrated a sensitivity of 63.0%, a specificity of 66%, a negative predictive value of 77%, a positive predictive evalue of 50.0%, and an overall accuracy of 65.0%. And for the lower thoracic wall, ultrasonography demonstrated a sensitivity of 81.0%, a specificity of 59.0%,a negative predictive value of 89.0%, a positive predictivevalue of 44.0%, and an overall accuracy of 65.0%. Conclusion Chest ultrasonography is moderately accurate in detecting the presence and location of pleural adhesions. The use of preoperative chest sonographic findings to plan trocar placement and to determine the need for an open approach is valuable in helping prevent visceral injury and facilitating video-assisted thoracoscopic surgery.

Is two lung ventilation with artificial pneumothorax a better choice than one lung ventilation in minimally invasive esophagectomy?

Two lung ventilation (TLV) with artificial pneumothorax has been introduced into MIE for several years. A few researches have reported its clinical application, and proved its safety and feasibility. However, it is still controversial whether TLV with artificial pneumothorax is a better choice than one lung ventilation (OLV). Obviously, single lumen endotracheal tube is easy for intubation and intraoperative maintenance. Potential problems during intervention include hemodynamic changes, oxygenation, and air embolism. In this paper, present literature is reviewed about two and one lung ventilation in thoracoscopy, looking for clear conclusions for future application.

Single lumen endotracheal intubation with carbon dioxide insufflation for lung isolation in thoracic surgery

INTRODUCTION

Double lumen tube (DLT) intubation is used for lung isolation but is not without disadvantages including increased intubation time, anesthesia expertise, risk of airway trauma, and costs over single lumen tube (SLT) intubation. SLT intubation with CO₂ insufflation can be used as an alternative for lung isolation. We reviewed our experience with this technique during thoracoscopic surgery.

METHODS

We performed a retrospective review of a prospectively maintained IRB-approved database from 2009 to 2018. Operations were performed with CO₂ insufflation up to 15 mmHg. Indications for surgery, operative details, intraoperative complications, pathology, and postoperative complications were reviewed.

RESULTS

We identified 123 patients (70 females [57%]) with a median age of 40 years (range 16-80 years) and a median BMI of 26.2 kg/m² (range 15-59 kg/m²) that underwent minimally invasive thoracoscopic procedures with this technique. Procedures included: mediastinal mass resection or biopsy (41%), sympathectomy (37%), wedge resection (10%), first rib resection (6%), diaphragm plication (2%), segmentectomy (2%), decortication (2%), pleural biopsy (2%), and pericardial cyst resection (1%). Median operative time was 90 min (range 25-584 min) and median intraoperative blood loss was 10 mL (range 2-200 mL). Intraoperative hemodynamic parameters were obtained at procedure start, 1 h after CO₂ insufflation, and at procedure completion: we observed significant changes in heart rate and systolic blood pressure (P = 0.027 and P < 0.001, respectively) although clinically inconsequential. Mean end-tidal CO₂ 1 h after insufflation was 36.6 ± 4.5 mmHg. There were no intraoperative complications and no conversions to a DLT. Median length of stay was 1 day (range 0-14 days). Five complications (4%) were observed and no mortalities.

CONCLUSIONS

SLT intubation and CO₂ insufflation is a feasible and safe alternative to DLT intubation for lung isolation. This can be a useful strategy to accomplish lung isolation for some thoracoscopic procedures, in particular when expertise for DLT placement is unavailable.

Thoracoscopic resection of mediastinal tumor in a patient with azygos continuation of the inferior vena cava

A 68-year-old man was referred to our hospital because of mediastinal tumor on chest computed tomography (CT). Contrast-enhanced CT showed azygos continuation of the inferior vena cava (IVC). The retro-hepatic IVC was absent superior to the renal veins. The IVC continued into the dilated azygos vein, which joined the superior vena cava. The hepatic vein drained directly into the right atrium. The mediastinal tumor was close to the dilated azygos vein. Video-assisted thoracoscopic resection of the mediastinal tumor was performed, using four ports and CO₂ insufflation. Histological examination of the resected specimen revealed a pericardial cyst without malignancy. After a favorable postoperative course, the patient was discharged 4 days after surgery. It is important to recognize this anomaly before thoracic surgery, because transection of the azygos vein can be fatal. Video-assisted thoracoscopic resection of mediastinal tumor close to the azygos vein using CO₂ insufflation avoids injury to the azygos vein.

A comparison between two lung ventilation with CO2 artificial pneumothorax and one lung ventilation during thoracic phase of minimally invasive esophagectomy

Background

To investigate the feasibility and safety of two lung ventilation with artificial pneumothorax in minimally invasive esophagectomy (MIE) through a comparison with conventional one lung ventilation.

Methods

Eleven hundred and sixty-six patients with esophageal cancer, who underwent McKeown MIE in our center from February 2006 to December 2016, were studied retrospectively. Seven hundred and five patients who underwent one lung ventilation with double lumen endotracheal tube (DLET) were assigned to DLET group. Other 461 patients who underwent two lung ventilation with single lumen endotracheal tube (SLET) were assigned to SLET group. Clinical characteristics, surgical variables and complications were compared between two groups.

Results

There were comparable patient characteristics in two groups. Surgical variables and complications were discussed between two groups. SLET group seemed to have shorter operative time, shorter postoperative hospital stay, and more harvested recurrent laryngeal nerve (RLN) lymph nodes than DLET group, which might be attributed to experienced surgeons. However, there were no significant differences of complications between two groups. Intraoperative clinical parameters were further studied. Before intubation and artificial pneumothorax, there were no significant differences between two groups, except diastolic blood pressure (DBP). With the application of artificial pneumothorax, patients in SLET group have obviously higher PO₂, PCO₂, and PetCO₂ value, and slightly lower pH value and blood pressure during thoracic phase. After the thoracic phase, the changes induced by artificial pneumothorax in SLET group were gradually reversed and clinical parameters gradually return to normal level.

Conclusions

Two lung ventilation with artificial pneumothorax is a safe and feasible choice during MIE.

Upper Gastrointestinal Surgery: Robotic Surgery versus Laparoscopic Procedures for Esophageal Malignancy

Background

The evolution of minimally invasive surgery (MIS) also extends to the field of esophageal surgery and has brought forth the development of several approaches of minimally invasive esophagectomy (MIE). Hybrid and total minimally invasive operative techniques have proven beneficial compared to open surgery and are currently evaluated against robotic-assisted minimally invasive esophagectomy (RAMIE). We aim to review the current literature regarding the position of MIE versus RAMIE.

Methods

A systematic review of the relevant literature on minimally invasive esophageal surgery for cancer is presented. A PubMed search was carried out for the period of 1992-2018 with the following search terms: 'esophageal cancer', 'minimally invasive surgery', 'resection', 'transhiatal', 'transthoracic', 'MIE', 'hybrid', 'robotic resection', 'RAMIE', 'RATE'.

Results

Hybrid and total minimally invasive operative techniques have proven beneficial, especially with regard to pulmonary complications, compared to open surgery. Oncologic outcomes appear equivalent between open and minimally invasive techniques. Currently, the position of RAMIE is being evaluated against other minimally invasive techniques.

Conclusion

All minimally invasive techniques confer the expected reduction in perioperative morbidity compared to open surgery. However, MIS is still evolving with regard to specific technical challenges, especially anastomotic techniques.

Efficacy of CO2 insufflation during thoracoscopic esophagectomy in the left lateral position

OBJECTIVE

Thoracoscopic esophagectomy (TE) is widely performed as a minimally invasive technique in the management of esophageal cancer. The aim of this study was to estimate the efficacy of intrathoracic carbon dioxide (CO₂) insufflation during TE in the left lateral position.

METHODS

From January 2010 to April 2016, 58 patients with esophageal cancer underwent TE without intrathoracic CO₂ insufflation (Group N) and 37 patients with esophageal cancer underwent TE with intrathoracic CO₂ insufflation (Group C). The operation results and respiratory parameters during the thoracic procedure were compared in both groups.

RESULTS

A satisfactory surgical field was obtained by CO₂ insufflation. There was no difference in the duration of the thoracic procedure or number of dissected mediastinal lymph nodes between the two groups. The amount of thoracic blood loss in Group C was significantly less than that in Group N (P < 0.05). Intrathoracic CO₂ insufflation did not affect oxygenation during single-lung ventilation. However, both end-tidal CO₂ (ETCO₂) 1 h after single-lung ventilation and maximum ETCO₂ in Group C were significantly higher than those in Group N. Intraoperative hypercapnia in Group C was permissive. The rate of extubation in the operation room, mortality and morbidity were not different between the two groups.

CONCLUSIONS

Intrathoracic CO₂ insufflation is beneficial to make satisfactory surgical field and to reduce thoracic blood loss in TE. Application of intrathoracic CO₂ insufflation may contribute to the widespread adoption of TE in the left lateral position.

Hybrid theatre and alternative localization techniques in conventional and single-port video-assisted thoracoscopic surgery

Management of pulmonary nodules in terms of diagnosis and intraoperative localization can be challenging, especially in the minimal invasive video-assisted thoracoscopic surgery (VATS) approach, and may be even more difficult with single port VATS with limited access. The ability to localize small lesions intraoperatively is particularly important for excisional biopsy for diagnostic frozen section, as well as to guide sublobar resection. Some of the common techniques to aid localization include preoperative percutaneous hookwire localization, colour dye or radio-dye labelling injection of the nodule or adjacent site to allowing visualization or detection by radioactive counter intraoperatively. The use of hybrid operating room (OR) for intraoperative localization of lung nodules was first reported in 2013, and was called image guided VATS (iVATS). Subsequently, we have expanded the iVATS application for single port VATS major lung resection of small or ground-glass opacity lesions. By performing an on-table cone-beam CT scan, real-time and accurate assessment of the pulmonary lesion can be made, which can aid the localization process. Other types of physical or colour marker that can be deployed percutaneously in the hybrid OR immediate before surgery can enhance haptic feedback and sensitivity of digital palpation, as well as provide a radiopaque nidus for radiological confirmation. In the past decade, the electromagnetic navigation bronchoscopy (ENB) technology had developed into a useful adjunct technology for the localization of peripheral lung nodules by injection of marking agent or deployment of fiducial to the lesion through the endobronchial route causing much lower marking agent diffusion and artefacts. Recently, the combination of hybrid OR and ENB for lung nodule localization and marking has further increased the accuracy and applicability of the technology. The article will be exploring the latest development of the above approaches to lung nodule localization, and discuss some of the techniques' advantages and flaws.

Impact of artificial capnothorax on coagulation in patients during video-assisted thoracoscopic esophagectomy for squamous cell carcinoma

BACKGROUND

Compared with the lung isolation using double-lumen endobronchial tube intubation, the artificial capnothorax using single-lumen endotracheal tube intubation has shown to be a safe, more convenient, and cost-effective procedure for thoracoscopic esophagectomy. However, the impact of capnothorax on coagulation is not well defined. Herein, we evaluate the impact of a capnothorax on coagulation and fibrinolysis in patients who undergoing thoracoscopic esophagectomy.

METHODS

Between March 2014 and August 2014, 24 patients underwent thoracoscopic esophagectomies for esophageal cancer with the procedure of artificial capnothorax (group P); we also performed 24 thoracoscopic esophagectomy cases without using capnothorax (group N). The demographics and arterial blood gas, as well as the parameters of coagulation and fibrinolysis, of the two groups were analyzed.

RESULTS

The pH value of group P after CO2 insufflation was significantly lower than in group N (P < 0.05), and the partial pressure of carbon dioxide (PaCO2) was significantly increased compared with group N (P < 0.05). The R and K values after CO2 insufflation were significantly longer than before anesthesia (P < 0.05), and both α angle and MA value after CO2 insufflation were significantly lower than those before anesthesia (P < 0.05). No significant differences in R value, K value, α angle, or MA value were observed between pre-anesthesia and termination of capnothorax. No significant difference in LY30 data was found between different groups (P > 0.05).

CONCLUSION

Artificial capnothorax in patients receiving endoscopic resection of esophageal carcinoma had a significant impact on coagulation. These patients showed significant impairments in coagulation not observed in patients without artificial capnothorax.

Real-time ventilation and perfusion distributions by electrical impedance tomography during one-lung ventilation with capnothorax

BACKGROUND

Carbon dioxide insufflation into the pleural cavity, capnothorax, with one-lung ventilation (OLV) may entail respiratory and hemodynamic impairments. We investigated the online physiological effects of OLV/capnothorax by electrical impedance tomography (EIT) in a porcine model mimicking the clinical setting.

METHODS

Five anesthetized, muscle-relaxed piglets were subjected to first right and then left capnothorax with an intra-pleural pressure of 19 cm H2 O. The contra-lateral lung was mechanically ventilated with a double-lumen tube at positive end-expiratory pressure 5 and subsequently 10 cm H2 O. Regional lung perfusion and ventilation were assessed by EIT. Hemodynamics, cerebral tissue oxygenation and lung gas exchange were also measured.

RESULTS

During right-sided capnothorax, mixed venous oxygen saturation (P = 0.018), as well as a tissue oxygenation index (P = 0.038) decreased. There was also an increase in central venous pressure (P = 0.006), and a decrease in mean arterial pressure (P = 0.045) and cardiac output (P = 0.017). During the left-sided capnothorax, the hemodynamic impairment was less than during the right side. EIT revealed that during the first period of OLV/capnothorax, no or very minor ventilation on the right side could be seen (3 ± 3% vs. 97 ± 3%, right vs. left, P = 0.007), perfusion decreased in the non-ventilated and increased in the ventilated lung (18 ± 2% vs. 82 ± 2%, right vs. left, P = 0.03). During the second OLV/capnothorax period, a similar distribution of perfusion was seen in the animals with successful separation (84 ± 4% vs. 16 ± 4%, right vs. left).

CONCLUSION

EIT detected in real-time dynamic changes in pulmonary ventilation and perfusion distributions. OLV to the left lung with right-sided capnothorax caused a decrease in cardiac output, arterial oxygenation and mixed venous saturation.

The application of single-lumen endotracheal tube anaesthesia with artificial pneumothorax in thoracolaparoscopic oesophagectomy

Double-lumen endotracheal tube (DLET) anaesthesia is the commonly used method in minimally invasive oesophagectomy (MIE). However, DLET intubation does have its disadvantages. Firstly, the placement of the DLET needs a skilled anaesthetist with familiarity of the technique and subsequent ability to perform a fibre-optic bronchoscopy for confirmation. Secondly, DLET intubation and one-lung ventilation are associated with numerous complications, including hoarseness, tracheobronchial injury and vocal injury. In this report, a retrospective analysis was performed on 42 consecutive patients who underwent MIE using single-lumen endotracheal tube (SLET) anaesthesia with CO2 artificial pneumothorax compared with 81 patients who underwent the same procedure with DLET intubation. Our findings showed that SLET intubation with artificial pneumothorax by CO2 insufflation is a feasible and safe method for MIE procedures.

Efficacy and safety of artificial pneumothorax under two-lung ventilation in thoracoscopic esophagectomy for esophageal cancer in the prone position

BACKGROUND

Thoracoscopic esophagectomy for esophageal cancer performed using two-lung ventilation in the prone position has many advantages, such as convenient anesthesia induction and maintenance, and good oxygenation. We examined the safety of surgery and anesthetic management by following chronological changes in intraoperative respiration and hemodynamics.

METHODS

We focused on the most recent and consecutive 14 cases of thoracoscopic esophagectomy for esophageal cancer in the prone position performed from November 2010 until recently. We measured the following items by use of FloTrac system : cardiac index (CI), central venous pressure (CVP), mean arterial pressure, partial pressure of oxygen in arterial blood (PaO2), partial pressure of carbon dioxide in arterial blood (PaCO2), peak airway pressure (APmax), and tidal volume.

RESULTS

No major changes were observed in CI, systolic blood pressure, and TV after the start of pneumothorax (statically not significant). Conversely, CVP increased immediately after pneumothorax (p < 0.05) and decreased almost to its original level thereafter. The mean APmax value was 18-20 cm H2O [mean increase, 4.2 cm H2O; (p < 0.05)]. The mean P/F ratio and mean PaCO2 were 244.4 and 48.3 mmHg, respectively, during artificial pneumothorax.

CONCLUSION

No excessive increases in airway pressure or clear circulatory depressions were observed because of artificial pneumothorax under two-lung ventilation in thoracoscopic esophagectomy for esophageal cancer in the prone position. These results suggest that artificial pneumothorax under two-lung ventilation is beneficial for maintaining stable hemodynamics and oxygenation in thoracoscopic esophagectomy in prone position.

Thoracoscopic enucleation of esophageal leiomyoma in prone position and single lumen endotracheal intubation

INTRODUCTION

Esophageal leiomyomas are the most common benign tumors of the esophagus. Surgical enucleation is warranted for symptomatic patients. Thoracoscopic enucleation is the preferable approach for being less invasive by avoiding the discomfort and complications associated to larger thoracic incisions. The purpose of this study was to review our experience with enucleation of esophageal leiomyoma using a prone-position thoracoscopy technique.

METHODS

Between January 2009 and July 2012, ten patients underwent resection of esophageal leiomyoma by thoracoscopy approach in prone position. Indications for surgical treatment were symptomatic tumors (dysphagia). All patients were followed postoperatively for at least 3 months with contrast x-ray of the esophagus. After single-lumen endotracheal intubation (nonselective intubation) in supine, patients were placed in prone position. Pneumothorax was kept at 6 to 8 mmHg using CO2 insufflation. A myotomy was performed over the tumor using hook cautery carefully protecting the mucosa from injuries. The myotomy was closed with continuous sutures.

RESULTS

The procedures were completed in the prone position in all cases, without any conversion. Mean operative time was 89.2 ± 28.7 minutes. Bleeding was negligible, and there were no intraoperative or postoperative complications. No intensive care unit support was needed for any patient. Chest x-ray in the first postoperative day showed no significant changes in any patient. The mean hospital stay was 3.2 days. Contrast x-ray of the esophagus was normal in all patients at 3 months postoperatively.

CONCLUSIONS

Thoracoscopic enucleation of esophageal leiomyoma is a feasible, simple, and safe procedure. Thoracoscopy in the prone position with CO2 insufflation allows the use of usual technique of intubation and also provides optimal operative field. The advantages of the thoracoscopic approach are less postoperative discomfort and lower risk of complications from open thoracotomy (especially pulmonary).

Right or left first during bilateral thoracoscopy?

BACKGROUND

Endoscopic thoracic sympathectomy (ETS) is now an established surgical technique for treatment of palmar hyperhidrosis that is performed under general anesthesia with positive pressure ventilation via either an endotracheal tube or a double lumen endobronchial tube. This is a bilateral disease that requires the division of the right and left thoracic sympathetic chain. The aim of this study was to compare the hemodynamic changes using a left capnothorax first versus right a capnothorax first surgical approach using a single lumen endotracheal tube in patients undergoing bilateral ETS. Lung collapse was achieved by carbon dioxide insufflation.

METHODS

Forty patients of both sexes aged 18-30 years and of American Society of Anesthesiologists grade I were randomly assigned to undergo bilateral ETS. Patients were divided into two groups. Group L comprised left capnothorax first, followed by right capnothorax (n = 20). Group R comprised right capnothorax first, followed by left capnothorax (n = 20). The anesthesia technique was standardized for all patients. Cardiovascular variables were determined during the procedure every minute. Statistical analysis was performed by independent-sample t test and Pearson's chi-square test.

RESULTS

There was a significant (P < 0.05) mean percentage decrease in systolic blood pressure in group L compared to group R. Similarly, the mean percentage decrease in diastolic blood pressure in group L was significant compared to group R (P < 0.05). Seven patients in group L developed bradycardia, but this was not found to be statistically significant.

CONCLUSIONS

When the left capnothorax first approach was used, there was significant hypotension, compared to a right capnothorax first thoracoscopy. We thus recommend that right capnothorax should be performed first in cases of bilateral ETS.

Surgical approaches for stage I and II thymoma-associated myasthenia gravis: feasibility of complete video-assisted thoracoscopic surgery (VATS) thymectomy in comparison with trans-sternal resection

Complete resection could be achieved in virtually all myasthenic patients with Masaoka stage I and II thymoma using the trans-sternal technique. Whether this is appropriate for minimally invasive approach is not yet clear. We evaluated the feasibility of complete video-assisted thoracoscopic surgery (VATS) thymectomy for the treatment of Masaoka stage I and II thymoma-associated myasthenia gravis, compared to conventional trans-sternal thymectomy. We summarized 33 patients with Masaoka stage I and II thymoma-associated myasthenia gravis between April 2006 and September 2011. Of these, 15 patients underwent right-sided complete VATS (the VATS group) by using adjuvant pneuomomediastinum, comparing with 18 patients using the trans-sternal approach (the T3b group). No intraoperative death was found and no VATS case required conversion to median sternotomy. Significant differences between the two groups regarding duration of surgery and volume of intraoperative blood loss (P = 0.001 and P < 0.001, respectively) were observed. Postoperative morbidities were 26.7% and 33.3% for the VATS and T3b groups, respectively. All 33 patients were followed up for 12 to 61 months in the study. The cumulative probabilities of reaching complete stable remission and effective rate were 26.7% (4/15) and 93.3% (14/15) in the VATS group, which had a significantly higher complete stable remission and effective rate than those in the T3b group (P = 0.026 and P = 0.000, respectively). We conclude that VATS thymectomy utilizing adjuvant pneuomomediastinum for the treatment of stage I and II thymoma-associated myasthenia gravis is technically feasible but deserves further investigation in a large series with long-term follow-up.

Anesthetic management of the patient with dilated cardiomyopathy undergoing pulmonary resection surgery: a case-based discussion

Interactions between the cardiovascular and respiratory systems are complex and profound. General anesthesia, muscle relaxation, and positive-pressure ventilation all impose physiological effects on cardiovascular function. In patients presenting for pulmonary resection, additional effects resulting from positioning, 1-lung ventilation, surgical procedures, and contraction of the pulmonary vascular bed may impose an additional physiological burden. For most patients with adequate pulmonary and cardiovascular reserve, these effects are well tolerated. However, the cardiothoracic anesthesiologist may be asked to provide anesthetic care for patients with significantly reduced cardiac function who require potentially curative pulmonary resection for lung cancer. These patients present a major perioperative challenge and a thoughtful approach to intraoperative management is required. The authors review a case of a patient with severely impaired biventricular function who presented for elective pulmonary lobectomy in an attempt to effect a curative resection of lung cancer and present a discussion of physiological and pathophysiological considerations for clinical management.

Anesthesia for thoracoscopic surgery

Anesthesia for thoracoscopy is based on one lung ventilation. Lung separators in the airway are essential tools. An anatomical shunt as a result of the continued perfusion of a non-ventilated lung is the principal intraoperative concern. The combination of equipment, technique and process increase risks of hypoxia and dynamic hyperinflation, in turn, potential factors in the development of an unusual form of pulmonary edema. Analgesia management is modelled on that shown effective and therapeutic for thoracotomy. Perioperative management needs to reflect the concern for these complex, and complicating, processes to the morbidity of thoracoscopic surgery.

Asystole following positive pressure insufflation of right pleural cavity: a case report

INTRODUCTION

Adverse hemodynamic effects with severe bradycardia have been previously reported during positive pressure insufflation of the right thoracic cavity in humans. To the best of our knowledge, this is the first report of asystole during thoracoscopic surgery with positive pressure insufflation.

CASE PRESENTATION

A 63-year-old Caucasian woman developed asystole at the onset of positive pressure insufflation of her right hemithorax during a thoracoscopic single-lung ventilation procedure. Immediate deflation of pleural cavity, intravenous glycopyrrolate and atropine administration returned her heart rhythm to normal sinus rhythm. The surgery proceeded in the absence of positive pressure insufflation without any further complications.

CONCLUSIONS

We discuss the proposed mechanisms of hemodynamic instability with positive pressure thoracic insufflation, and anesthetic and insufflation techniques that decrease the likelihood of adverse hemodynamic events.

Thoracoscopic sympathectomy

With the advent of videotechnology, sympathectomy has assumed a more important role in the armamentarium of managing diseases of the autonomic system. Currently it is used primarily for hyperhydrosis, although sympathectomy for reflex sympathetic dystrophy (RSD), Raynaud disease and other diseases still are performed, but less frequently. Most of this article will refer primarily to hyperhydrosis patients.

Natural orifice transesophageal thoracoscopic surgery: A review of the current state

Since the concept of Natural Orifice Translumenal Endoscopic Surgery (NOTES) was introduced, it has continued to gain significantly in popularity and enthusiasm for its potential clinical applications. The ability to perform conventional laparoscopic and thoracoscopic procedures without the creation of scars and perhaps faster and less painful recovery has prompted a worldwide devotion to further this field. While intra-abdominal NOTES has rapidly transitioned from animal models to human trials, applying the NOTES concept to perform thoracic procedures has been slower to gain momentum. The goal of this review is to summarize the current state of transesophageal NOTES thoracoscopy by looking at its potential for diagnostic and therapeutic interventions as well as the challenges in transitioning to human trials.

Selective lobar collapse for video-assisted thoracic surgery

BACKGROUND

Video-assisted thoracic surgery (VATS) is conventionally performed under single-lung ventilation. A small proportion of patients are often excluded from undergoing VATS because of their inability to tolerate single-lung ventilation. We describe a simple technique of selective lobar lung collapse that may help to recruit additional, selected patients for VATS.

METHODS

We use a standard suction catheter placed under bronchoscopic guidance to the target lobar bronchus through a single-lumen endotracheal tube. The catheter is left open to air, or suction can be applied to facilitate lobar collapse. The remaining lobe of the same lung can be ventilated throughout surgery. Surgery is performed using standard VATS techniques.

RESULTS

Using this technique we have successfully performed VATS on 63 chest sides in 35 patients. The procedures performed included thoracodorsal sympathectomies (n = 28), mechanical pleurodesis procedures (n = 3), mediastinal and pleural biopsies (n = 2), and lung wedge resections (n = 2). We encountered no mortality or morbidity in all cases.

CONCLUSIONS

This technique is simple and safe and requires no expensive disposable devices. Although not essential for most patients undergoing VATS, it deserves to be in the armamentarium of the thoracic surgeon. Further studies will be required to better define its application in clinical practice.

Anaesthesia for thoracoscopic surgery

The surgical requirement for thoracoscopy is a good view of the contents of the thorax. This is achieved by capitalizing on natural consequences and the skills of anaesthesiologists to produce a pneumothorax and collapse the ipsilateral lung--a process that is commonly enhanced by insufflating carbon dioxide. Insufflating CO2 to actively promote lung collapse creates the dynamics of a tension pneumothorax. Complications are clinically insignificant if CO2 is used judiciously. There is a body of experience using ordinary endotracheal tubes and two-lung ventilation. Techniques of one-lung ventilation are more widely reported. All the factors known to contribute to the significant increase in shunt fraction associated with one-lung ventilation apply. The manoeuvre of collapsing a lung is no longer regarded as benign. Chemical attempts to produce a reversible post-pneumonectomy pulmonary circulation have not been shown to be an improvement. Post-operative pain can be severe. The mechanism is not defined but it differs from that associated with thoracotomy. Epidural analgesia and opioids may be required. Chronic pain syndromes have been described as complications.

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

A study of 10 anaesthetised patients placed in the lateral position for thoracoscopic surgery assessed whether transient increases in pleural pressure on the side of the non-ventilated lung might increase the speed at which gas vents from that lung. The transient increases in pleural pressure were generated by the mediastinal displacement that occurs with each inspiratory phase of positive pressure ventilation of the dependent lung. When combined with a unidirectional valve allowing gas to flow out of the non-ventilated lung, and a second valve allowing ambient airflow into, but not out of, the thoracic cavity via an initial thoracoscopy access site, this mediastinal displacement could conceivably serve to 'pump' gas out of the non-ventilated lung. Using the four different combinations of valve inclusion or omission, the volume of gas that vented from the non-ventilated lung into a measuring spirometer was recorded during a 120-s measurement sequence. It was found that the speed of venting was not increased by the transient increases in pleural pressure, and that in all but one of a total of 34 measurement sequences, venting had ceased by the end of the sequence. Gas venting was a mean (SD) of 85.5 (11.9)% complete in 25 s (five breaths), and 96.6 (6.1)% complete in 60 s. This prompt partial lung collapse very likely reflected the passive elastic recoil of the lung, while the failure of transient increases in pleural pressure to result in ongoing venting of gas was probably a consequence of airways closure as the lung collapsed. It is concluded that techniques that aim to speed lung collapse by increasing pleural pressure are unlikely to be effective.

Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting

BACKGROUND

In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypass grafting. Studies on the effects of unilateral CO2 insufflation on hemodynamics produced controversial results, and bilateral insufflation has not been studied to our knowledge. The present study sought to investigate hemodynamics and gas exchange during unilateral and bilateral CO2 insufflation in patients who underwent totally endoscopic coronary artery bypass grafting.

METHODS

Eleven hemodynamic and gas exchange variables were monitored during 22 totally endoscopic coronary artery bypass grafting procedures with unilateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, after institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation.

RESULTS

Arterial oxygen tension decreased significantly during SLV, whereas the peak inspiratory pressure increased. In addition, central venous pressure and heart rate increased significantly during insufflation, but mean arterial pressure remained unchanged. Although the end-tidal CO2 pressure did not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and between groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unaltered. No patient required inotropic or vasopressor support.

CONCLUSIONS

Carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting with SLV had no adverse effects on hemodynamics. In contrast to a moderate increase of arterial carbon dioxide tension during unilateral insufflation, markedly elevated arterial carbon dioxide tension levels remain a cause of concern during bilateral insufflation.

Thoracoscopic and laparoscopic staging for esophageal cancer

Accurate pretreatment staging for patients with esophageal cancer (EC) is becoming increasingly important in the evaluation and comparison of different treatment modalities. Noninvasive staging methods are imperfect in detecting lymph node metastasis in patients with EC. Surgical staging with the thoracoscopic/laparoscopic (Ts/Ls) technique may provide accurate staging information that is useful for evaluating and comparing the results of clinical trials of preoperative chemotherapy and radiotherapy. It can be used to confirm or exclude suspicious distant metastasis found by other staging methods. Pretreatment (lymph node) biopsies obtained by Ts/Ls staging allow further molecular biologic analysis to detect occult lymph node metastasis for more accurate lymph node staging. Since 1992, we have used Ts/Ls staging for EC in 111 patients. We found that Ts/Ls is a promising method for staging lymph nodes in EC patients. A recent study showed that pretreatment surgical lymph node staging can predict response and survival for EC patients receiving trimodality treatment (ie, radiation, chemotherapy, and surgery). The information obtained with surgical staging now offers us the opportunity to optimize therapy to specific patient groups based on the extent of disease at the time of initial presentation. Nevertheless, unlike the practice of mediastinoscopy in lung cancer patients, Ts/Ls staging in EC patients remains an academic interest rather than a clinical practice. The concept of accurate pretreatment staging of EC remains to be realized and accepted in the clinical community.

Anesthesia for Thoracoscopy

Provision of anesthesia care to patients undergoing thoracoscopic procedures, especially video-assisted thoracoscopy, requires thorough knowledge of the sur gical procedure and the physiology of one-lung ventila tion, as well as meticulous attention to detail by the anesthesia personnel caring for these patients. Thoracos copy is used increasingly to perform almost the entire range of thoracic surgical procedures in a minimally invasive fashion. Excellent quality anesthetic care is necessary to assure the benefits of minimally invasive surgery to the maximum number of patients undergo ing thoracic surgery. This article will provide anesthesi ologists caring for patients undergoing thoracoscopy with the necessary working knowledge of the technical aspects of the procedure and understanding of the relevant anesthetic implications. Preoperative, intraop erative, and postoperative concerns will be addressed. The scope of this article will be limited to noncardiac uses of thoracoscopy.

Haemodynamic changes during thoracoscopic surgery the effects of one-lung ventilation compared with carbon dioxide insufflation

We investigated the haemodynamic and respiratory effects of one-lung ventilation and carbon dioxide insufflation in 13 adult patients undergoing video-assisted thoracoscopy. Cardiorespiratory variables were determined during carbon dioxide insufflation at intrahemithoracic pressures of 5, 10 and 15 mmHg, and after 5 and 15 min of one-lung ventilation. Carbon dioxide insufflation was associated with a clear deterioration in circulatory function. The cardiac index decreased subsequent to increasing intrathoracic pressures. The mean cardiac index (SD) at pressures of 10 and 15 mmHg was 1.86 (0.39) and 1.52 (0.46), respectively, and may be compared with the reduced venous return consistent with tension pneumothorax. One-lung ventilation did not affect haemodynamic variables but reduced arterial oxygenation indices (PaO2/FIO2) from 424.29 (160.79) after induction of anaesthesia, to 207.72 (125.50) after 5 min and 172.04 (72.03) after 15 min of one-lung ventilation, respectively. The oxygenation index was not influenced by intrahemithoracic carbon dioxide insufflation. One-lung ventilation via a double-lumen endobronchial tube is safe and convenient for video-assisted thoracoscopic surgery. It has no further consequences on haemodynamic variables, whereas the compression of the lung by carbon dioxide insufflation may cause circulatory dysfunction.

Thoracoscopic versus open partial pericardectomy in dogs: comparison of postoperative pain and morbidity

OBJECTIVE

To evaluate postoperative pain and morbidity in dogs undergoing open thoracotomy and partial pericardectomy versus thoracoscopic pericardectomy.

STUDY DESIGN

Research study in normal dogs.

ANIMALS OR SAMPLE POPULATION

Fourteen mixed breed healthy dogs.

METHODS

Seven dogs had a partial pericardectomy through a standard left lateral thoracotomy at the fifth intercostal space. The remaining seven dogs underwent selective lung ventilation and thoracoscopic partial pericardectomy. Surgery sites in both groups were bandaged and each dog received a single postoperative dose of morphine (0.2 mg/kg, intramuscularly [i.m.]). Postoperative pain was evaluated using a standard pain score table at 1, 5, 9, 17, 29, and 53 hours after surgery. Dogs receiving a pain score of six or greater received an additional dose of morphine. At each observation point, blood samples were taken to measure blood glucose and plasma cortisol concentrations. Pain scores, blood glucose, and plasma cortisol concentrations were compared between the two groups using two-way ANOVA.

RESULTS

Blood glucose concentrations, plasma cortisol concentrations, and pain scores were significantly different between the two groups, with the thoracotomy dogs having higher values at 1, 5, and 9 hours postoperatively. Three of the open thoracotomy dogs required additional analgesia after the initial dose of morphine. In addition, two dogs that underwent open thoracotomy were lame in the left forelimb and two others developed dehiscence of their wounds.

CONCLUSIONS AND CLINICAL RELEVANCE

Thoracoscopic partial pericardectomy has several advantages over open partial pericardectomy including decreased postoperative pain, fewer wound complications, and more rapid return to function.