Toward a Next-Generation Digital Chest Tube.

Chest tubes in patients who have undergone pulmonary resection with pleural air leak are painful, impair ventilatory mechanics, and increase hospital length of stay and costs. Despite these well-documented concerns, current protocols for chest tube management in this setting are not well supported by evidence. Excessive suction applied to chest tubes has been associated with prolonged air leak due to alveolar over-distension, and most practitioners intuit that suction should be minimized to the lowest level needed to maintain desired pleural apposition. Unfortunately, there is no evidence-based protocol for the establishment of minimal adequate suction. Digital suction devices in current clinical use can identify air leak resolution preventing the delay of chest tube removal but cannot guide suction minimization while an air leak persists. We recently described a monitor of lung expansion in a porcine model of pleural air leak that could detect loss of pleural apposition continuously in real-time based on electrical impedance readings obtained directly from the surface of the lung via chest tube-embedded electrodes. The value of the impedance signal was "in-range" when pleural apposition was present but became abruptly "out-of-range" when pneumothorax due to inadequate suction developed. These findings suggested that a digitally controlled suction pump system could be programmed to recognize the development of pneumothorax and automatically identify and set the minimum level of suction required to maintain pleural apposition. We present here preliminary proof of concept for this system.

Pleural electrical impedance is a sensitive, real-time indicator of pneumothorax.

BACKGROUND: Chest tube management protocols, particularly in patients with alveolar-pleural air leak due to recent surgery or trauma, are limited by concerns over safety, especially concerns about rapid and occult development of pneumothorax. A continuous, real-time monitor of pneumothorax could improve the quality and safety of chest tube management. We developed a rat model of pneumothorax to test a novel approach of measuring electrical impedance within the pleural space as a monitor of lung expansion. MATERIALS AND METHODS: Anesthetized Sprague-Dawley rats underwent right thoracotomy. A novel impedance sensor and a thoracostomy tube were introduced into the right pleural space. Pneumothorax of varying volumes ranging from 0.2 to 20 mL was created by syringe injection of air via the thoracostomy tube. Electrical resistance measurements from the pleural sensor and fluoroscopic images were obtained at baseline and after the creation of pneumothorax and results compared. RESULTS: A statistically significant, dose-dependent increase in electrical resistance was observed with increasing volume of pneumothorax. Resistance measurement allowed for continuous, real-time monitoring of pneumothorax development and the ability to track pneumothorax resolution by aspiration of air via the thoracostomy tube. Pleural resistance measurement demonstrated 100% sensitivity and specificity for all volumes of pneumothorax tested and was significantly more sensitive for pneumothorax detection than fluoroscopy. CONCLUSIONS: The electrical impedance-based pleural space sensor described in this study provided sensitive and specific pneumothorax detection, which was superior to radiographic analysis. Real-time, continuous monitoring for pneumothorax has the potential to improve the safety, quality, and efficiency of postoperative chest tube management.

Ex vivo drug testing of patient-derived lung organoids to predict treatment responses for personalized medicine.

Lung cancer is the leading cause of global cancer-related mortality resulting in âˆ¼ 1.8 million deaths annually. Systemic, molecular targeted, and immune therapies have provided significant improvements of survival outcomes for patients. However, drug resistance usually arises and there is an urgent need for novel therapy screening and personalized medicine. 3D patient-derived organoid (PDO) models have emerged as a more effective and efficient alternative for ex vivo drug screening than 2D cell culture and patient-derived xenograft (PDX) models. In this review, we performed an extensive search of lung cancer PDO-based ex vivo drug screening studies. Lung cancer PDOs were successfully established from fresh or bio-banked sections and/or biopsies, pleural effusions and PDX mouse models. PDOs were subject to ex vivo drug screening with chemotherapy, targeted therapy and/or immunotherapy. PDOs consistently recapitulated the genomic alterations and drug sensitivity of primary tumors. Although sample sizes of the previous studies were limited and some technical challenges remain, PDOs showed great promise in the screening of novel therapy drugs. With the technical advances of high throughput, tumor-on-chip, and combined microenvironment, the drug screening process using PDOs will enhance precision care of lung cancer patients.

Diagnosis of anastomotic leak: electrolyte detection versus barium fluoroscopy.

BACKGROUND: We recently described a new method of diagnosing anastomotic leak using the detection of electrical changes induced by electrolyte extravasation from a surgically created gastric leak site in experimental rats. We sought to compare the sensitivity and specificity of anastomotic leak detection for this method to that of upper gastrointestinal (GI) barium fluoroscopy. METHODS: Experimental rats with a surgically created gastric leak site and controls were interrogated as to the presence of leak using either the electrolyte-gated leak detection method or upper GI barium fluoroscopy. The sensitivity and specificity of leak detection for the two methods were compared. RESULTS: The sensitivity and specificity of electrolyte-gated leak detection were both 100% (95% confidence interval 69-100%). Barium upper GI fluoroscopy misidentified one leak as a control and one control as a leak, for a sensitivity and specificity of 80% each (95% confidence interval 37-97%). No statistically significant difference was seen between electrolyte-gated leak detection and barium upper GI fluoroscopy in terms of the sensitivity and specificity of anastomotic leak detection. CONCLUSIONS: Electrolyte-gated leak detection was similarly sensitive and specific for anastomotic leak detection as upper GI barium fluoroscopy, the current standard. The electrolyte-gated method has the advantages of an inert contrast agent (normal saline) and the possibility of performing leak interrogation at the bedside. Electrolyte-gated leak detection might represent a plausible alternative to upper GI barium fluoroscopy for routine postoperative anastomotic leak surveillance after esophagectomy or other foregut surgery.

AXL-initiated paracrine activation of pSTAT3 enhances mesenchymal and vasculogenic supportive features of tumor-associated macrophages.

Tumor-associated macrophages (TAMs) are integral to the development of complex tumor microenvironments (TMEs) and can execute disparate cellular programs in response to extracellular cues. However, upstream signaling processes underpinning this phenotypic plasticity remain to be elucidated. Here, we report that concordant AXL-STAT3 signaling in TAMs is triggered by lung cancer cells or cancer-associated fibroblasts in the cytokine milieu. This paracrine action drives TAM differentiation toward a tumor-promoting "M2-like" phenotype with upregulation of CD163 and putative mesenchymal markers, contributing to TAM heterogeneity and diverse cellular functions. One of the upregulated markers, CD44, mediated by AXL-IL-11-pSTAT3 signaling cascade, enhances macrophage ability to interact with endothelial cells and facilitate formation of primitive vascular networks. We also found that AXL-STAT3 inhibition can impede the recruitment of TAMs in a xenograft mouse model, thereby suppressing tumor growth. These findings suggest the potential application of AXL-STAT3-related markers to quantitatively assess metastatic potential and inform therapeutic strategies in lung cancer.

Lung lobectomy surgical approach and resource utilization differ by anatomic lobe in a statewide discharge registry.

Background: Anatomic lobe-specific differences with respect to pulmonary lobectomy have been suggested in the thoracic surgery literature but hard data has been lacking in larger population studies in part due to coding systems that do not distinguish pulmonary lobectomy by anatomic lobe. International Classification of Diseases, Tenth Revision (ICD-10) procedure codes, adopted in the United States in 2015, may provide novel methodologic accessibility for pulmonary lobectomy studies as they classify lobectomy operations by specific anatomic lobe. We queried the Texas Inpatient Public Use Data File (TPUDF) ICD-10 codes for both open and endoscopic approach lobectomy with a specific view to differences based on anatomic lobes. Methods: Between fourth fiscal quarter (Q4) 2015 and Q4 2017, all pulmonary lobectomy operations performed in Texas state-licensed hospitals were identified by querying the TPUDF for ICD-10 procedure codes for pulmonary lobectomy as classified by anatomic lobe. Surgical approach, additional procedures and diagnosis codes, length of hospital stay (LOS), and discharge status were recorded with aggregate values undergoing statistical analysis. Results: Right and left upper versus lower lobe resections were more prevalent however minimally invasive surgery was less commonly performed for upper than right lower lobectomy. LOS, irrespective of surgical approach, was longer for upper versus lower lobe resection as was need for transfer to additional inpatient facilities. LOS was longer and need for additional surgical or procedural interventions days after the primary procedure of lobectomy was greater for right versus left upper lobe resection, suggesting some differential properties of the right versus left pleural space. Conclusions: The marked clinical differences between anatomic lobes in the setting of pulmonary lobectomy observed in this study have the potential to translate to differences in expected hospital and health system costs and surgeon time-expenditure and experience premium that currently have no mechanism for their accounting. These findings highlight the value of ICD-10 coding for analysis of pulmonary lobectomy in administrative databases and suggest a possible path to more informed patient counseling and equitable hospital and surgeon reimbursement based on payment adjustment by anatomic lobe in pulmonary lobectomy operations.

Intrapleural Impedance Sensor Real-Time Tracking of Pneumothorax in a Porcine Model of Air Leak.

In patients with alveolar-to-pleural air leak due to recent surgery or trauma, clinicians tend to manage chest tubes with suction therapy. Nonsuction therapy is associated with shorter chest tube duration but also a higher risk of pneumothorax. We sought to develop an intrapleural electrical impedance sensor for continuous, real-time monitoring of pneumothorax development in a porcine model of air leak as a means of promoting nonsuction therapy. Using thoracoscopy, 2 chest tubes and the pleural impedance sensor were introduced into the pleural space of 3 pigs. Continuous air leak was introduced through 1 chest tube by carbon dioxide insufflation. The second chest tube was placed to suction then transitioned to no suction at increasingly higher air leaks until pneumothorax developed. Simultaneously, real-time impedance measurements were obtained from the pleural sensor. Fluoroscopy spot images were captured to verify the presence or absence of pneumothorax. Statistical Analysis Software was used throughout. With the chest tube on suction, a fully expanded lung was identified by a distinct pleural electrical impedance respiratory waveform. With transition of the chest tube to water seal, loss of contact of the sensor with the lung resulted in an immediate measurement of infinite electrical impedance. Pneumothorax resolution by restoring suction therapy was detected in real time by a return of the normal respiratory impedance waveform. Pleural electrical impedance monitoring detected pneumothorax development and resolution in real time. This simple technology has the potential to improve the safety and quality of chest tube management.

Single-Cell Proteomic Profiling Identifies Combined AXL and JAK1 Inhibition as a Novel Therapeutic Strategy for Lung Cancer.

Cytometry by time-of-flight (CyTOF) simultaneously measures multiple cellular proteins at the single-cell level and is used to assess intertumor and intratumor heterogeneity. This approach may be used to investigate the variability of individual tumor responses to treatments. Herein, we stratified lung tumor subpopulations based on AXL signaling as a potential targeting strategy. Integrative transcriptome analyses were used to investigate how TP-0903, an AXL kinase inhibitor, influences redundant oncogenic pathways in metastatic lung cancer cells. CyTOF profiling revealed that AXL inhibition suppressed SMAD4/TGFß signaling and induced JAK1-STAT3 signaling to compensate for the loss of AXL. Interestingly, high JAK1-STAT3 was associated with increased levels of AXL in treatment-naïve tumors. Tumors with high AXL, TGFß, and JAK1 signaling concomitantly displayed CD133-mediated cancer stemness and hybrid epithelial-to-mesenchymal transition features in advanced-stage patients, suggesting greater potential for distant dissemination. Diffusion pseudotime analysis revealed cell-fate trajectories among four different categories that were linked to clinicopathologic features for each patient. Patient-derived organoids (PDO) obtained from tumors with high AXL and JAK1 were sensitive to TP-0903 and ruxolitinib (JAK inhibitor) treatments, supporting the CyTOF findings. This study shows that single-cell proteomic profiling of treatment-naïve lung tumors, coupled with ex vivo testing of PDOs, identifies continuous AXL, TGFß, and JAK1-STAT3 signal activation in select tumors that may be targeted by combined AXL-JAK1 inhibition. SIGNIFICANCE: Single-cell proteomic profiling of clinical samples may facilitate the optimal selection of novel drug targets, interpretation of early-phase clinical trial data, and development of predictive biomarkers valuable for patient stratification.

Video-assisted thoracoscopic surgery lobectomy for stage I lung cancer.

The literature shows that, in the hands of experienced thoracoscopic surgeons, VL is a safe operation that offers patients at least comparable complication and survival rates compared with lobectomy by thoracotomy. VL can be performed safely with proven advantages over conventional thoracotomy for lobectomy: smaller incisions, decreased postoperative pain, decreased LOS, decreased chest tube output and duration, decreased blood loss, better preservation of pulmonary function, and earlier return to normal activities. These results are obtained without sacrificing the oncologic principles of thoracic surgery, and, in fact, the evidence in the literature is mounting that VATS may offer reduced rates of complications and better survival.

The efficacy of inhaled nanoparticle tacrolimus in preventing rejection in an orthotopic rat lung transplant model.

OBJECTIVE: The immunosuppressive efficacy of inhaled nanoparticle tacrolimus was compared with systemic tacrolimus in a rodent allogeneic lung transplant model. METHODS: Sixteen rats underwent allogeneic left orthotopic lung transplantation and were divided into 3 treatment groups: (1) inhaled nanoparticle tacrolimus: 6.4 mg tacrolimus/6.4 mg lactose twice per day; (2) intramuscular tacrolimus: 1 mg/kg tacrolimus once per day; and (3) inhaled lactose: 6.4 mg of lactose twice per day. Five days after transplant, the rats were necropsied and underwent histologic rejection grading and cytokine analysis. Trough levels of tacrolimus were measured in allograft, blood, and kidney. RESULTS: Both intramuscular (n = 6) and nanoparticle tacrolimus (n = 6) rats displayed lower histologic grades of rejection (mean scores 3.4 ± 0.6 and 4.6 ± 0.9, respectively) when compared with lactose rats (n = 4) (mean score 11.38 ± 0.5, P = .07). Systemic tacrolimus trough levels (median) were lower in nanoparticle tacrolimus-treated rats versus intramuscular-treated rats (29.2 vs 118.6 ng/g; P < .001 in kidney, and 1.5 vs 4.8 ng/mL; P = .01 in blood). CONCLUSIONS: Inhaled nanoparticle tacrolimus provided similar efficacy in preventing acute rejection when compared with systemic tacrolimus while maintaining lower systemic levels.

Online learning in thoracic surgical training: promising results of multi-institutional pilot study.

BACKGROUND: Cardiothoracic surgical education faces numerous challenges, including reduced duty hours and diminishing prioritization of teaching, in the setting of rapidly advancing knowledge, skills, and case complexity. Pass rates on the American Board of Thoracic Surgery exam remain suboptimal, and new training formats are being evaluated. We hypothesize that Internet-based courses can be developed and implemented to supplement learning of basic topics in cardiothoracic surgery. METHODS: After a needs assessment, 4 online self-study courses were developed by content experts using a Moodle [modular object-oriented dynamic learning environment] platform. As a pilot cohort, students from 4 thoracic surgery training programs participated, accessing courses at their own pace. Each course included general and detailed readings, multimedia content, discussion forum, and a question-bank supported quiz (90% required to pass, multiple attempts allowed). Utilization and exam data were tracked electronically. The t tests were used to compare first versus final-year traditional track trainees. Post-course surveys collected data on trainee attitudes. RESULTS: Nineteen students completed 4 courses on tracheal disease. Mean time spent per course and quiz attempts to pass were 1.35 hours and 2.86, respectively. Scores improved with successive attempts. Senior trainees showed a trend toward less time per course and fewer quiz attempts. Post-course surveys uniformly demonstrated perceived benefits from the content and quizzes in an easy-to-navigate format. CONCLUSIONS: Online courses can be developed and integrated within cardiothoracic training programs. This pilot demonstrates evidence of active learning as shown through the embedded assessments. Internet-based courses may serve as a means of supplementing modern thoracic surgical training. Further development and evaluation are warranted.

Effect of inhaled tacrolimus on ischemia reperfusion injury in rat lung transplant model.

OBJECTIVE: Systemic tacrolimus therapy has been shown to protect against lung ischemia-reperfusion injury in animal models. We sought to investigate on a functional and cellular level if inhaled nanoparticle tacrolimus administered to the donor lung before procurement could similarly attenuate ischemia-reperfusion injury after lung transplant. METHODS: An isogenic orthotopic rat model of single left lung transplant was used. Donor animals were pretreated with inhaled tacrolimus (treatment group) or inhaled lactose (controls) before lung procurement. Lung grafts were subjected to 3 hours of cold ischemia followed by 4 hours of reperfusion after graft implantation. Recipient animal arterial blood gas measurement and isograft wet to dry weight ratios were obtained. Macrophage, neutrophil, and T-cell accumulation and activation in lung isografts, including γδ T-cell, T-helper, and cytotoxic T-cell subtypes were analyzed by flow cytometry. Tacrolimus levels were measured in the lung isograft using liquid chromatography/mass spectrometry. Isograft cytokine levels were measured with commercial enzyme-linked immunosorbent assay and microbead array kits. RESULTS: Oxygenation in treatment group animals was significantly higher than in controls. The presence of macrophages, neutrophils, and all T-cell subtypes in the isografts as well as isograft levels of inflammatory cytokines were all less in the treatment group versus controls, although no single variable achieved statistical significance. CONCLUSIONS: Inhaled nanoparticle tacrolimus treatment of lung donors is associated with an attenuation of ischemia-reperfusion injury on a functional and cellular level in lung transplant.

Transthoracic repair of slipped Nissen fundoplications: technique and results.

BACKGROUND: Laparoscopic Nissen fundoplication is a common operation performed for reflux disease, generally with good results. A small percentage of patients experience transthoracic migration of the wrap, causing recurrent symptoms and eventually requiring transthoracic repair. METHODS: A retrospective chart review was performed for all patients who underwent a transthoracic repair of a slipped Nissen fundoplication at our institution from 2006 to 2010. Data included demographics, previous antireflux operations, symptoms at presentation, findings at operation, and overall outcome. RESULTS: Sixteen patients with a mean age of 61 years (range, 51-76 years) were identified who fit inclusion criteria. The most common presenting symptom was pain. Intraoperative findings included hiatal breakdown in all patients, shortened esophagus in 10 (62%) patients, and foreign body/mesh in 4 (25%) patients. Nine (56%) patients underwent a Collis gastroplasty along with a Nissen fundoplication. Nissen fundoplication alone was performed in 6 (38%) patients and a Belsey fundoplication with a Collis gastroplasty was performed in 1 (6%) patient. Minor complications occurred in 4 (25%) patients and major complications were seen in 2 (13%) patients. The median length of stay was 9 days (range, 6-30 days). There were no postoperative deaths. Overall, 12 (75%) of the patients were judged to have a good outcome, 3 (19%) a fair outcome, and 1 (6%) a poor outcome over a median 9-month follow-up. CONCLUSIONS: Transthoracic repair in patients who have had transthoracic migration of a previous Nissen fundoplication has acceptable surgical outcome and affords symptomatic relief to the majority of patients.

Feasibility of video-assisted thoracoscopic surgery lobectomy in Veterans Administration patients.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) pulmonary lobectomy has been associated with decreased complication rates and length of stay compared with lobectomy by thoracotomy. No studies have addressed VATS lobectomy in Veterans Administration (VA) patients. METHODS: A retrospective review was undertaken of 50 VATS lobectomies performed between August 2007 and June 2009 by one surgeon in a VA hospital, a university-affiliated county hospital, and a private community hospital. RESULTS: VA patients had more medical comorbidities, poorer lung function, greater current smoker status, and fewer preoperative biopsies. Pleural adhesions or hilar lymphadenopathy were encountered more commonly in VA than nonfederal patients. Surgical times and number of procedures performed were greater in VA patients. There was no statistically significant difference in the risk of postoperative complications or chest tube duration although length of stay was longer for VA patients. CONCLUSIONS: VATS lobectomy is feasible in a VA setting. The evidence strongly suggests that veterans can benefit from VATS lobectomy in terms of improved outcomes and diminished length of stay compared with thoracotomy.

Birt-hogg-dubé syndrome: answering questions raised by a case report published in 1962.

In 1962, J.J. Collins from the United States Naval Medical Research Laboratory published an unusual case of air embolism precipitated by decompression in The New England Journal of Medicine [1962;266:595-598]. The case was unusual because it was the first where multiple pulmonary cysts were discovered after a successful recompression treatment. Although various hypotheses were put forward by the author, it was thought that the diver might have had 'subclinical cysts' already present because of some disease phenomenon, which then became overinflated during decompression. Nearly 50 years have passed since these questions were raised. Interestingly, now the disease process is trying to unveil itself through various other clues. We present the case of the same diver who later developed a series of other medical problems, along with more than 5 admissions for spontaneous pneumothoraces, all falling into the constellation represented by the Birt-Hogg-Dubé syndrome. Birt-Hogg-Dubé syndrome is an autosomal dominant condition clinically characterized by skin fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax, and renal cancer. It was first described in 1977 by Birt, Hogg and Dubé in a family with 'hereditary multiple fibrofolliculomas with trichodiscomas and acrochordons'. Spontaneous pneumothorax can be the first manifestation of this hereditary condition, and prevention in patients diagnosed with the syndrome is aimed at early diagnosis and treatment of the renal cell carcinoma. Physicians need to have a high index of suspicion when they see patients with the constellation of findings of this underdiagnosed syndrome, especially in patients with unexplained spontaneous pneumothoraces.

Anastomotic leak detection by electrolyte electrical resistance.

OBJECTIVE: To characterize a new method of postoperative gastrointestinal leak detection based on electrical resistance changes due to extravasated electrolyte contrast. BACKGROUND: Postoperative gastrointestinal leak results in increased patient morbidity, mortality, and hospital costs that can be mitigated by early diagnosis. A sensitive and specific diagnostic test that could be performed at the bedside has the potential to shorten the time to diagnosis and thereby improve the quality of treatment. MATERIALS AND METHODS: Anaesthetized rats underwent celiotomy and creation of a 5-mm gastrotomy. In experimental animals, electrical resistance changes were measured with a direct current ohmmeter after the introduction of 5 cc of 23.4% NaCl electrolyte solution via gavage and measured with a more sensitive alternating current ohmmeter after the gavage of 1-5 cc of 0.9% NaCl. Comparison was made to negative controls and statistical analysis was performed. RESULTS: Leakage from the gastrotomy induced by as little as 1 cc of gavage-delivered 0.9% NaCl contrast solution was detectable as a statistically significant drop in electrical resistance when compared to results from negative controls. CONCLUSION: Electrical resistance change associated with electrolyte-gated leak detection is highly sensitive and specific and has the potential to be rapidly translated into clinical settings.

Damage control: cavoatrial anastomosis during a catastrophic right intrapericardial pneumonectomy.

While undergoing an intrapericardial pneumonectomy for a massive right pulmonary inflammatory pseudotumor that had invaded the mediastinum, an 18-year-old woman experienced a nearly fatal iatrogenic complication. Dense scarring adjacent to the pseudotumor had drawn in the superior vena cava posterolaterally and fused the right main pulmonary artery to the right superior pulmonary vein within the pericardium. The failure of a linear stapler to secure the pulmonary vessels led to torrential hemorrhage. Attempts to control the bleeding resulted in inadvertent superior vena cava occlusion and central venous pressure elevation. Because cardiopulmonary bypass might not have been reliably established in time to avoid irreversible cerebral ischemia, we borrowed a technique from congenital heart surgery and rapidly fashioned a cavoatrial connection. The patient survived the operation without negative neurologic or cardiac sequelae, recovered fully, and had no recurrence of the pseudotumor. Herein, we describe the intraoperative decisions that were made under intense time pressure to avert catastrophe.

Photodynamic therapy followed by thoracoscopic sleeve lobectomy for locally advanced lung cancer.

Photodynamic therapy is an effective technique for debulking endobronchial tumors over an acceptably short time-course; however, to be effective, numerous treatment cycles may be required to achieve the desired results. We present a case in which photodynamic therapy was used with curative intent to downsize an obstructing endobronchial non-small cell lung cancer in advance of resection via video-assisted thoracoscopic surgery with right upper lobe sleeve lobectomy.