Comparison of Uniportal versus Multiportal Video-Assisted Thoracoscopic Surgery Pulmonary Segmentectomy / 대한흉부외과학회지

BACKGROUND: Uniportal video-assisted thoracoscopic surgery (VATS) has proven safe and effective for pulmonary wedge resection and lobectomy. The objective of this study was to evaluate the safety and feasibility of uniportal VATS segmentectomy by comparing its outcomes with those of the multiportal approach at a single center. METHODS: The records of 84 patients who underwent VATS segmentectomy from August 2010 to August 2018, including 33 in the uniportal group and 51 in the multiportal group, were retrospectively reviewed and analyzed. RESULTS: Anesthesia and operative times were similar in the uniportal and multiportal groups (215 minutes vs. 220 minutes, respectively; p=0.276 and 180 minutes vs. 198 minutes, respectively; p=0.396). Blood loss was significantly lower in the uniportal group (50 mL vs. 100 mL, p=0.013) and chest tube duration and hospital stay were significantly shorter in the uniportal group (2 days vs. 3 days, p=0.003 and 4 days [range, 1–14 days] vs. 4 days [range, 1–62 days], p=0.011). The number of dissected lymph nodes tended to be lower in the uniportal group (5 vs. 8, p=0.056). CONCLUSION: Our preliminary experience indicates that uniportal VATS segmentectomy is safe and feasible in well-selected patients. A randomized, prospective study with a large group of patients and long-term follow-up is necessary to confirm these results.

Prognostic role of beclin-1 in locally advanced non-small cell lung cancer in patients receiving docetaxel-platinum induction chemotherapy

BACKGROUND/AIMS@#The outcome of local treatment for advanced non-small cell lung cancer (NSCLC) remains poor, with therapies such as induction chemotherapy (IC) yielding conflicting results. This study aimed to assess the clinicopathologic and prognostic significance of the excision repair cross-complementation group 1 (ERCC1), beclin-1, and glucose-regulated protein of molecular mass 78 (GRP78) in patients with locally advanced NSCLC receiving docetaxel-platinum IC, along with efficacy and safety.@*METHODS@#This is a retrospective observational cohort study. We reviewed medical records of 31 NSCLC patients receiving docetaxel-platinum IC, and conducted immunohistochemical staining of ERCC1, beclin-1, and GRP78.@*RESULTS@#Response rate was 67.8% with 10.7 months of median relapse-free survival (RFS) and 23.1 months of median overall survival (OS), and no treatment-related death was reported. High expression of ERCC1, beclin-1, and GRP78 was identified in 67.7%, 87.1%, and 67.7%, respectively. Expression of ERCC1 and GRP78 did not reveal statistical significance in survival, whereas high beclin-1 expression revealed longer OS (7.6 months vs. 23.2 months; log-rank p = 0.024). In multivariate analysis, histologic differentiation (hazard ratio [HR], 3.48; p < 0.001), stage (HR, 8.5; p = 0.024), and adjuvant treatment (HR, 16.1; p = 0.001) were related to RFS, and in OS, stage (HR, 5.4; p = 0.037), adjuvant treatment (HR, 8.6; p = 0.004), and beclin-1 expression (HR, 8.2; p = 0.011) were identified as significant prognostic factors.@*CONCLUSIONS@#Our findings suggest that high beclin-1 expression predicts longer survival in locally advanced NSCLC and docetaxel-platinum IC is a treatment option that deserves consideration.

Comparison of Uniportal versus Multiportal Video-Assisted Thoracoscopic Surgery Pulmonary Segmentectomy

BACKGROUND@#Uniportal video-assisted thoracoscopic surgery (VATS) has proven safe and effective for pulmonary wedge resection and lobectomy. The objective of this study was to evaluate the safety and feasibility of uniportal VATS segmentectomy by comparing its outcomes with those of the multiportal approach at a single center.@*METHODS@#The records of 84 patients who underwent VATS segmentectomy from August 2010 to August 2018, including 33 in the uniportal group and 51 in the multiportal group, were retrospectively reviewed and analyzed.@*RESULTS@#Anesthesia and operative times were similar in the uniportal and multiportal groups (215 minutes vs. 220 minutes, respectively; p=0.276 and 180 minutes vs. 198 minutes, respectively; p=0.396). Blood loss was significantly lower in the uniportal group (50 mL vs. 100 mL, p=0.013) and chest tube duration and hospital stay were significantly shorter in the uniportal group (2 days vs. 3 days, p=0.003 and 4 days [range, 1–14 days] vs. 4 days [range, 1–62 days], p=0.011). The number of dissected lymph nodes tended to be lower in the uniportal group (5 vs. 8, p=0.056).@*CONCLUSION@#Our preliminary experience indicates that uniportal VATS segmentectomy is safe and feasible in well-selected patients. A randomized, prospective study with a large group of patients and long-term follow-up is necessary to confirm these results.

Clinical Characteristics of False-Positive Lymph Node on Chest CT or PET-CT Confirmed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration in Lung Cancer / 결핵및호흡기질환

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure to evaluate suspicious lymph node involvement of lung cancer because computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography-CT (PET-CT) have limitations in their sensitivity and specificity. There are a number of benign causes of false positive lymph node such as anthracosis or anthracofibrosis, pneumoconiosis, old or active tuberculosis, interstitial lung disease, and other infectious conditions including pneumonia. The purpose of this study was to evaluate possible causes of false positive lymph node detected in chest CT or PET-CT. METHODS: Two hundred forty-seven patients who were initially diagnosed with lung cancer between May 2009 and December 2012, and underwent EBUS-TBNA to confirm suspicious lymph node involvement by chest CT or PET-CT were analyzed for the study. RESULTS: Of 247 cases, EBUS-TBNA confirmed malignancy in at least one lymph node in 189. The remaining 58 patients whose EBUS-TBNA results were negative were analyzed. Age ≥65, squamous cell carcinoma as the histologic type, and pneumoconiosis were related with false-positive lymph node involvement on imaging studies such as chest CT and PET-CT. CONCLUSION: These findings suggest that lung cancer staging should be done more carefully when a patient has clinically benign lymph node characteristics including older age, squamous cell carcinoma, and benign lung conditions.

Nonintubated Uniportal Video-Assisted Thoracoscopic Surgery: A Single-Center Experience

BACKGROUND: We report our surgical technique for nonintubated uniportal video-assisted thoracoscopic surgery (VATS) pulmonary resection and early postoperative outcomes at a single center. METHODS: Between January and July 2017, 40 consecutive patients underwent nonintubated uniportal VATS pulmonary resection. Multilevel intercostal nerve block was performed using local anesthesia in all patients, and an intrathoracic vagal blockade was performed in 35 patients (87.5%). RESULTS: Twenty-nine procedures (72.5%) were performed in patients with lung cancer (21 lobectomies, 6 segmentectomies, and 2 wedge resections), and 11 (27.5%) in patients with pulmonary metastases, benign lung disease, or pleural disease. The mean anesthesia time was 166.8 minutes, and the mean operative duration was 125.9 minutes. The mean postoperative chest tube duration was 3.2 days, and the mean hospital stay was 5.8 days. There were 3 conversions (7.5%) to intubation due to intraoperative hypoxemia and 1 conversion (2.5%) to multiportal VATS due to injury of the segmental artery. There were 7 complications (17.5%), including 3 cases of prolonged air leak, 2 cases of chylothorax, 1 case of pleural effusion, and 1 case of pneumonia. There was no in-hospital mortality. CONCLUSION: Nonintubated uniportal VATS appears to be a feasible and valid surgical option, depending on the surgeon’s experience, for appropriately selected patients.

Coexistence of an EGFR Mutation and an ALK Rearrangement in a Patient with Lung Adenocarcinoma: a Case Report / 대한내과학회지

A 58 year-old woman was diagnosed with lung adenocarcinoma (cT3N1M0). We detected a point mutation in epidermal growth factor receptor (EGFR) exon 21 (L858R) and an echinoderm microtubule-associated protein-like 4- anaplastic lymphoma kinase (ALK) rearrangement. The patient was treated with preoperative neoadjuvant chemotherapy and underwent a left lower lobectomy with mediastinal lymph node dissection. However, we could not detect any mutation in EGFR or the ALK rearrangement from the tumor tissue removed. Then, 70 days after completion of adjuvant chemotherapy, she visited our outpatient clinic with diminished visual accuracy and tinnitus. A single brain metastatic lesion was seen on brain magnetic resonance imaging. She underwent surgical removal of the brain mass, which showed a mutation of EGFR, exon 21, but no ALK rearrangement. We report this unusual case of lung adenocarcinoma with a coexisting EGFR mutation and ALK rearrangement, and identify gene alterations before chemotherapy, after chemotherapy, and at recurrence.

The Korean guideline for lung cancer screening

Lung cancer is the leading cause of cancer death in many countries, including Korea. The majority of patients are inoperable at the time of diagnosis because symptoms are typically manifested at an advanced stage. A recent large clinical trial demonstrated significant reduction in lung cancer mortality by using low dose computed tomography (LDCT) screening. A Korean multisociety collaborative committee systematically reviewed the evidences regarding the benefits and harms of lung cancer screening, and developed an evidence-based clinical guideline. There is high-level evidence that annual screening with LDCT can reduce lung cancer mortality and all-cause mortality of high-risk individuals. The benefits of LDCT screening are modestly higher than the harms. Annual LDCT screening should be recommended to current smokers and ex-smokers (if less than 15 years have elapsed after smoking cessation) who are aged 55 to 74 years with 30 pack-years or more of smoking-history. LDCT can discover non-calcified lung nodules in 20 to 53% of the screened population, depending on the nodule positivity criteria. Individuals may undergo regular LDCT follow-up or invasive diagnostic procedures that lead to complications. Radiation-associated malignancies associated with repetitive LDCT, as well as overdiagnosis, should be considered the harms of screening. LDCT should be performed in qualified hospitals and interpreted by expert radiologists. Education and actions to stop smoking must be offered to current smokers. Chest radiograph, sputum cytology at regular intervals, and serum tumor markers should not be used as screening methods. These guidelines may be amended based on several large ongoing clinical trial results.

Laparoscopic gastric tube formation with pyloromyotomy for reconstruction in patients with esophageal cancer

PURPOSE: To analyze the benefit and feasibility of this procedure compared with those of open method. METHODS: Abdominal procedure includes laparoscopic gastric mobilization, celiac axis lymph node dissection, formation of the gastric tube, and pyloromyotomy. The actual procedure performed during open surgery is the same as those of laparoscopic surgery except for the main incision. Minimally invasive esophagectomy (MIE) was performed on 54 patients with esophageal cancer. The short-term outcomes, including postoperative complications were analyzed and compared with 44 cases of open method. RESULTS: Although the total operative time was not different between 2 groups (349.8 minutes vs. 374.8 minutes, P = 0.153), the operation time of abdominal procedure was shorter in laparoscopic group (90.6 minutes vs. 162.1 minutes, P < 0.001). Operation related complications and hospital stay were not significantly different between the 2 groups. The number of transfused patients was significantly smaller in laparoscopic group (11.1% vs. 27.9%, P = 0.030). CONCLUSION: Laparoscopic gastric tubing with pyloromyotomy is a feasible and safe treatment option for patients with esophageal cancer.

A Rare Case of Mediastinal Granular Cell Tumor

The granular cell tumor (GCT) occurs extremely rarely in the mediastinum. Few mediastinal GCT cases have been reported in Japan or other countries. Here, we report a case of a 24-year-old man with superior mediastinal GCT. The mass was located just above the aortic arch. It was firm, oval in shape, and well encapsulated. The tumor was removed completely with video-assisted thoracoscopic surgery, but we had to resect the vagus nerve, which was already included in the tumor, along with the tumor. After the operation, the patient recovered without any specific complications except for a mild degree of hoarseness.

Novel Laparoscopic Gastric Tubing with Pyloromyotomy for Treatment of Esophageal Cancer

PURPOSE: We report on a novel method and outcomes of laparoscopic gastric tubing with pyloromyotomy. METHODS: The abdominal procedure includes laparoscopic gastric mobilization, celiac axis lymph node dissection, formation of the gastric tube, and pyloromyotomy. Between January 2009 and April 2013, our minimally invasive esophagectomy (MIE) was performed on 54 patients with esophageal cancer. The short-term outcomes, including postoperative complications, were analyzed. RESULTS: There were no cases of conversion to open surgery. Of 54 patients, 52 patients had squamous cell carcinoma (SCC) and two had adenocarcinoma. The total operative time was 349.8+/-77.4 minutes, of which 90.6+/-27.6 minutes was required for the abdominal procedure. The mean estimated operative blood loss during the abdominal procedure was 40.0+/-355.5 ml. The postoperative complication rate was 24.1%; three patients died of pneumonia. CONCLUSION: Laparoscopic gastric tubing with pyloromyotomy is a feasible and safe treatm ent option for patients with esophageal cancer.

Genome-Wide Association Study of Lung Cancer in Korean Non-Smoking Women

Lung cancer in never-smokers ranks as the seventh most common cause of cancer death worldwide, and the incidence of lung cancer in non-smoking Korean women appears to be steadily increasing. To identify the effect of genetic polymorphisms on lung cancer risk in non-smoking Korean women, we conducted a genome-wide association study of Korean female non-smokers with lung cancer. We analyzed 440,794 genotype data of 285 cases and 1,455 controls, and nineteen SNPs were associated with lung cancer development (P < 0.001). For external validation, nineteen SNPs were replicated in another sample set composed of 293 cases and 495 controls, and only rs10187911 on 2p16.3 was significantly associated with lung cancer development (dominant model, OR of TG or GG, 1.58, P = 0.025). We confirmed this SNP again in another replication set composed of 546 cases and 744 controls (recessive model, OR of GG, 1.32, P = 0.027). OR and P value in combined set were 1.37 and < 0.001 in additive model, 1.51 and < 0.001 in dominant model, and 1.54 and < 0.001 in recessive model. The effect of this SNP was found to be consistent only in adenocarcinoma patients (1.36 and < 0.001 in additive model, 1.49 and < 0.001 in dominant model, and 1.54 and < 0.001 in recessive model). Furthermore, after imputation with HapMap data, we found regional significance near rs10187911, and five SNPs showed P value less than that of rs10187911 (rs12478012, rs4377361, rs13005521, rs12475464, and rs7564130). Therefore, we concluded that a region on chromosome 2 is significantly associated with lung cancer risk in Korean non-smoking women.

Total Gastrectomy in Gastric Conduit Cancer

We report a very rare case of surgery on gastric conduit cancer. A 67-year-old male patient underwent esophagectomy and intrathoracic esophagogastrostomy for squamous cell carcinoma of the lower thoracic esophagus 27 months ago. Upon follow-up, a gastric carcinoma at the intra-abdominal part of the gastric conduit was found on an esophagogastroduodenoscopy. We performed total gastrectomy and esophagocolonojejunostomy in the manner of Roux-en-Y anastomosis. The postoperative course was not eventful and an esophagogram on the 10th postoperative day showed no leakage or stenosis of the passage. The patient was discharged on the 17th day with no complications.

Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review

BACKGROUND/AIMS: We made a systematic review and evaluation of endoscopic cryotherapy of endobronchial tumors, investigating safety and efficacy. METHODS: Qualified studies regarding endoscopic cryotherapy of lung tumors were systemically evaluated using available databases according to predefined criteria. RESULTS: In total, 16 publications were included in the final assessment. A narrative synthesis was performed because a formal meta-analysis was not viable due to the lack of controlled studies and study heterogeneity. Overall success rates for significant recanalization of the obstruction were approximately 80%, although they varied, depending on disease status in the patient population. Complications from the procedure developed in 0-11.1% of cases, most of which were minor and controlled by conservative management. Although limited data were available on comprehensive functional assessment, some studies showed that respiratory symptoms, pulmonary function tests, and performance status were significantly improved. CONCLUSIONS: Endoscopic cryotherapy was found to be a safe and useful procedure in the management of endobronchial tumors although its efficacy and appropriate indications have yet to be determined in well-designed controlled studies.

Diffuse Alveolar Hemorrhage in a 39-year-old Woman: Unusual Initial Presentation of Microscopic Polyangiitis

Microscopic polyangiitis (MPA) is a necrotizing vasculitis involving the small vessels without granulomatous inflammation. Most MPA initially presents with renal involvement without pulmonary involvement. Isolated and initially presenting alveolar hemorrhage is very rare. The patient was a 39-year-old female with a progressive cough, dyspnea, and blood-tinged sputum for the previous 5 days. We determined that her condition was MPA though VATS lung biopsy and renal biopsy. After 2 months of steroid therapy, the chest lesions had improved. We report here a rare case of MPA with isolated and initial involvement of the lung with a review of the literature.

Outcome of Limited Resection for Lung Cancer

BACKGROUND: Up to now, lobectomy, bilobectomy and pneumonectomy combined with extensive lymph node dissection have been regarded as the standard procedures for non-small cell lung cancer (NSCLC). In high-risk patients, however, limited resection (LR) has been attempted as a salvage procedure, and, recently, indication for LR has been extended to selected cases with early-stage NSCLC. MATERIAL AND METHODS: Among the 773 patients who underwent surgical procedures for NSCLC in Seoul National University Bundang Hospital from May 2003 to December 2008, 43 patients received LR. Medical records of these patients were retrospectively reviewed. RESULTS: Mean age at operation was 66.0+/-12.4 years, and there were 30 males. Twenty-five patients underwent conservative limited resection (CLR) and 18 underwent intentional limited resection (ILR). Indications for CLR were multiple primary lung cancer in 9 (9/25, 36%) and severe concomitant diseases in 5 (5/25, 20%). Of these, 6 patients underwent segmentectomy and 19 received wedge resection. During the follow-up period of 28.0+/-17.8 months, 15 patient developed recurrent lung cancer. ILR was selectively performed in lesions almost purely composed of ground glass opacity (> or =95%), or in small solid lesions (< or =2 cm). Of these, 11 patients underwent segmentectomy and 7 underwent wedge resection. During the follow-up period of 31.7+/-11.6 months, no patient developed recurrence. CONCLUSION: Intermediate-term outcome of LR for early-stage lung cancer is comparable to that of standard operation. For the delineation of the indications and appropriate surgical techniques for LR, prospective randomized multi-institutional study may be expedient.

Superior Vena Cava Resection and Reconstruction in Thoracic Malignancy / 대한흉부외과학회지

BACKGROUND: The benefit of superior vena cava (SVC) resection in thoracic malignancies remains controversial. We analyzed the results of extended resection in patients with thoracic malignancy involving the SVC. MATERIAL AND METHOD: From March 2000 to March 2009, we performed surgical resection and reconstruction in 18 thoracic malignancies involving the SVC. Ten male and 8 female enrolled and their mean age was 56 years. RESULT: SVC reconstruction was performed in 9 patients with polytetrafluoroethylene (PTFE) graft. Primary closure was possible in 6 patients by partially clamping the SVC. Patch angioplasty was performed in 3 patients with PTFE or autologous pericardial patch. Three-year survival was 58.0% and median survival time was 24.5 months. Disease specific survival and recurrence free survival were not significantly different between lung cancer and mediastinal malignancy. Obstruction of graft was detected in 4 patients during follow-up; SVC graft obstruction in 1 patient, and accessory graft between the innominate vein and right atrium in 3 patients. CONCLUSION: Extended resection of thoracic malignancies involving the SVC was a feasible method in selected patients. Although the morbidity rate was relatively high, mid-term survival was acceptable when complete resection was possible.

Retrograde Autologous Priming: Is It Really Effective in Reducing Red Blood Cell Transfusions during Extracorporeal Circulation? / 대한흉부외과학회지

BACKGROUND: Retrograde autologous priming (RAP) is known to be useful in decreasing the need of transfusions in cardiac surgery because it prevents excessive hemodilution due to the crystalloid priming of cardiopulmonary bypass circuit. However, there are also negative side effects in terms of blood conservation. We analyzed the intraoperative blood-conserving effect of RAP and also investigated the efficacy of autotransfusion and ultrafiltration as a supplemental method for RAP. MATERIAL AND METHOD: From January 2005 to December 2007, 117 patients who underwent isolated coronary artery bypass operations using cardiopulmonary bypass (CPB) were enrolled. Mean age was 63.9+/-9.1 years (range 36~83 years) and 34 patients were female. There were 62 patients in the RAP group and 55 patients in he control group. Intraoperative autotransfusion was performed via the arterial line. RAP was done just before initiating CPB using retrograde drainage of the crystalloid priming solution. Both conventional (CUF) and modified (MUF) ultrafiltrations were done during and after CPB, respectively. The transfusion threshold was less than 20% in hematocrit. RESULT: Autotransfusions were done in 79 patients (67.5%) and the average amount was 142.5+/-65.4 mL (range 30~320 mL). Homologous red blood cell (RBC) transfusion was done in 47 patients (40.2%) and mean amount of transfused RBC was 404.3+/-222.6 mL. Risk factors for transfusions were body surface area (OR 0.01, 95% CI 0.00~0.63, p=0.030) and cardiopulmonary bypass time (OR 1.04, 95% CI 1.01~1.08, p=0.019). RAP was not effective in terms of the rate of transfusion (34.5% vs 45.2%, p=0.24). However, the amount of transfused RBC was significantly decreased (526.3+/-242.3ml vs 321.4.+/-166.3 mL, p=0.001). Autotransfusion and ultrafiltration revealed additive and cumulative effects in decreasing transfusion amount (one; 600.0+/-231.0 mL, two; 533.3+/-264.6 mL, three; 346.7+/-176.7 mL, four; 300.0+/-146.1 mL, p=0.002). CONCLUSION: Even though RAP did not appear to be effective in terms of the number of patients receiving intraoperative RBC transfusions, it could conserve blood in terms of the amount transfused and with the additive effects of autotransfusion and ultrafiltration. If we want to maximize the blood conserving effect of RAP, more aggressive control will be necessary - such as high threshold of transfusion trigger or strict regulation of crystalloid infusion, and so forth.

Video-Assisted Thoracic Surgery Lobectomy for Non-SmallCell Lung Cancer: Experience of 133 Cases / 대한흉부외과학회지

BACKGROUND: We evaluated the feasibility and the efficacy of Video-Assisted Thoracic Surgery (VATS) lobectomy for treating patients with non-small cell lung cancer (NSCLC) and we compared the outcomes of VATS lobectomy with those of open lobectomy. MATERIAL AND METHOD: From 2003 to March 2008, 133 NSCLC patients underwent VATS lobectomy. The patients were selected on the basis of having clinical stage I disease on the chest CT and PET scan. The outcomes of 202 patients who underwent open lobectomy (OL group) for clinical stage I NSCLC were evaluated to compare their results with those of the patients who underwent VATS lobectomy (the VL group). RESULT: The number of females and the number of patients with adenocarcinoma and stage IA disease were greater in VL group (p<0.05). There was no operative mortality or major complications in the VL group. Conversion to thoracotomy was needed in 8 cases (6%), which was mostly due to bleeding. The chest tube indwelling time and the length of the postoperative hospital stay were significantly shorter in the VL group (p<0.001). The number of dissected lymph nodes and the size of tumor were significantly smaller in the VL group (p<0.001). For the pathologic stage I patients, there was no significant difference in the three-year survival rates between the two groups (p=0.15). CONCLUSION: VATS lobectomy is a safe procedure with low operative mortality and morbidity. VATS lobectomy is feasible for early stage NSCLC and it provides outcomes that are comparable to those for open lobectomy. Further long-term data are needed

Carinal Resection and Reconstruction for Carinal Tumor / 대한흉부외과학회지

Carinal resection is technically demanding and the surgical risk is relatively high. When tumor is confined around the carina, then lung parenchymal sparing surgery is technically feasible in selected cases. We performed carinal resection and reconstruction without pulmonary resection for a patient suffering with squamous cell carcinoma that involved the carina and this patient had undergone right upper lobectomy 19 months previously due to lung cancer.

The Effects of Nitric Oxide and Sphingosine 1-phosphate on the Pulmonary Microstructure in a Rat Model of Acute Lung Injury: An Intravital Videomicroscopic Approach / 대한흉부외과학회지

BACKGROUND: To evaluate the effects of inhaled nitric oxide (NO) and sphingosine 1-phosphate (S1P) as potential therapeutic agents of acute lung injury, we analyzed the morphology in vivo of the pulmonary microstructure using intravital videomicroscopy in a rat model of acute lung injury. MATERIAL AND METHOD: Sprague Dawley rats were divided into five groups: a control group that underwent normal saline aspiration, an acute lung injury (ALI) group that underwent hydrochloric acid aspiration, and three treatment groups that underwent hydrochloric acid aspiration and were administered therapeutic agents- the S1P group, the NO group, and the S1P+NO group (n=7 per group). To quantify alveolar compliance and interstitial edema, the diameters of all measurable alveoli and interalveolar septa were averaged at one and two hours after aspiration. Alveolar compliance was determined according to diameter changes during the respiratory cycle and the change in tidal volume. RESULT: At two hours after aspiration, the mean alveolar compliance (% change) in the ALI group decreased significantly versus the control group of rats (respiratory cycle: 1.9% for the ALI group vs 6.5% for the control group, p=0.03; tidal volume: 3.2% for the ALI group vs 9.1% for the control group, p=0.003) and versus the NO group (tidal volume: 3.2% for the ALI group vs 16.9% for the NO group, p=0.001). At two hours after aspiration, the mean interalveolar septal thickness in the NO group tended to be smaller as compared to that in the ALI group (15.2micrometer for the ALI group vs 12.3micrometer for the NO group, p=0.06). S1P did not exert a significant effect on the pulmonary microstructure of the injured rat lung. CONCLUSION: Improved alveolar compliance and reduced interstitial edema, observed by intravital videomicroscopy, suggest that inhaled NO ameliorates lung injury.