Extensive Lung Resection Research Articles

Uniportal Thoracoscopic Complex Combined Seg-Sub-subsegmentectomy of RS9+10bii: Dual-Display Method and Combined Approaches (Trans-fissure and Trans-ligament).

Uniportal thoracoscopic lateral basal segmentectomy is the most technically challenging anatomic segmentectomy,1-3 especially when it involves combined subsegmentectomy or sub-subsegmentectomy. Therefore, there are very few reports detailing its technical aspect. In this multimedia article, we describe a very complex uniportal thoracoscopic combined seg-sub-subsegmentectomy of RS9+10bii through the oblique fissure approach and the inferior pulmonary ligament approach, following a single-direction strategy4,5 to advance the procedure, utilizing the stem-branch method3,6 for segmental/subsegmental/sub-subsegmental structure tracking, and employing dual-display method, which comprises the intravenous ICG injection method and the inflation/deflation method, to identify intersegmental and inter-seg-sub-subsegmental planes. The operation lasted 169min, with approximately 20mL of blood loss. The patient experienced an active hemothorax and two spontaneous pneumothoraxes on postoperative days 1, 4, and 19, respectively, all of which resolved promptly after treatment. Histopathological examination of the specimen documented invasive non-mucinous adenocarcinoma with negative surgical margins and lymph nodes. The staging was determined as pT1bN0M0, stage IA2. During the 14-month follow-up period, there were no signs of tumor recurrence or metastasis observed. The FVC, FEV1, and FEV1%pred decreased by 11.9%, 12.5%, and 12.8%, respectively, at postoperative month 6. Complex basal segmentectomies, which necessitate combined subsegmental or sub-subsegmental resections, such as RS9+10bii, are feasible using the dual-display and combined approaches method. This method simplifies the steps of the very complex combined subsegmentectomy, averting the need for extensive lung resection. In addition, when performing these combined segmentectomies, precise anatomical dissection is crucial to prevent complications such as minor bronchopleural fistulas.

Safety of lung resection surgery after severe acute respiratory syndrome coronavirus 2 infection in the post-vaccination era.

To investigate the postoperative outcomes of lung resection in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and determine the optimal timing of surgery. This retrospective, single-centre cohort study included patients who underwent lung resection between June 2021 and June 2022. Patients were divided into the coronavirus disease 2019 (COVID-19) and non-COVID-19 groups based on their preoperative SARS-CoV-2 infection history, and postoperative outcomes were compared. Logistic regression analysis was conducted to identify the risk factors of complications after lung resection surgery. In total, 1194 patients were enrolled, of whom, 79 had a history of SARS-CoV-2 infection. In the COVID-19 group, 66 patients (90.4%) had received at least 1 vaccination dose. The average interval between infection and surgery was 67 days, with no significant impact on postoperative outcomes. Regarding postoperative outcomes, there were no significant differences in major complication rate (6.3% vs 5.4%, P = 0.613), respiratory complication rate (19.0% vs 12.2%, P = 0.079) or length of stays (4.9 ± 3.4 vs 5.0 ± 5.6, P = 0.992) between the 2 groups. Multivariate logistic regression analysis revealed that age, male sex, poor pulmonary function test, open surgery and extensive lung resection were risk factors for postoperative complications, while preoperative COVID-19 infection status was not a statistically significant risk factor. In the post-vaccination era, lung resection surgery can be safely performed shortly after SARS-CoV-2 infection, even within 4 weeks of infection.

Pulmonary vein stump thrombosis after lung resection for lung cancer: clinical features and outcome.

Pulmonary vein stump thrombosis (PVST) is uncommonly encountered postoperative in-situ thrombosis in the stump of pulmonary veins after lung resection. Data regarding the incidence and clinical behaviour of PVST are scarce. Thus, this study aims to investigate the incidence, clinical characteristics and outcome of PVST after lung resection in patients with lung cancer. Follow-up enhanced chest computed tomography (CT) scans acquired after the surgery were retrospectively reviewed to determine PVST presence for patients with lung cancer who underwent lung resection in two tertiary referral centres. Out of the 1885 patients with lung cancer who underwent lobectomy or more extensive lung resection, PVST was observed in 37 patients (2.0%) on their follow-up chest CT. Most stump thrombi were observed in the left superior pulmonary vein [35 (94.6%)] and in patients who underwent left upper lobectomy [34 (91.9%)]. At the last CT follow-up of each patient, 33 (89.2%) exhibited complete resolution, three partial resolution and one stabilization. Eleven (29.7%) patients received anticoagulant therapy after the diagnosis. The rate of complete PVST resolution did not differ significantly between the anticoagulation and nonanticoagulation groups. None of the PVST patients experienced systemic embolic events, regardless of anticoagulation. The PVST incidence diagnosed at routine chest CT follow-up following lung cancer surgery was 2%. PVST was characterized by a benign clinical course without progression and systemic embolization, regardless of anticoagulation. However, further studies are required to determine individualized therapeutic strategies, including anticoagulation.

Prospective evaluation of watchful waiting for early-stage lung cancer with ground-glass opacity: a single-arm confirmatory multicenter study: Japan Clinical Oncology Group study JCOG1906 (EVERGREEN study).

Among early-stage lung cancers that show ground-glass nodules on chest computed tomography, the lung cancer surgical study group of the Japan Clinical Oncology Group previously reported that nodules of ≤2 cm with a consolidation/tumor ratio of ≤0.25 were considered radiologically non-invasive cancers with a low risk of metastasis. However, there is no consensus based on high-quality evidence about the optimal timing of surgical intervention for radiologically non-invasive cancers. In June 2020, we launched a multi-institutional, single-arm confirmatory trial to evaluate the efficacy and safety of watchful waiting for patients with radiologically non-invasive lung cancer. It is planned that a total of 720 patients will be enrolled from 49 institutes over a 5-year period. The primary endpoint is 10-year overall survival (OS). The secondary endpoints are 5-year OS, operation-free survival, proportion of extensive lung resection, proportion of unresectable progression, lung cancer-specific survival and adverse events.

Preoperative evaluation of the pacient with bronchopulmonary cancer

BACKGROUND.In the Republic of Moldova, we have reported 983 cases of bronchopulmonary cancer (BPC) annually, in 2019. This impressive number of patients requires a more efficient mobilization of the medical system to solve these cases. AIM. The high incidence of newly diagnosed cases of BPC in advanced stages implies a reserved attitude for the surgical treatment of these patients, as well as the presence of associated pathologies, compromise more the situations, and the possibility to provide effective solutions to solve these cases. The group of patients who have tertiary prevention as a measure of treatment becomes imposing. This order of ideas outlines the need for a different medical-surgical approach for this category of patients. METHODS AND RESULTS.For the assessment of functional criteria for operability for patients with BPC, especially in advanced lung cancer, using comorbidity scores (ASA, Charlson, Elixhauser) and the formation of indications for surgical treatment are significant, because surgery offers the greatest opportunity for healing. The team responsible for the preoperative assessment should include both a perioperative mortality risk assessment and a postoperative pulmonary function prediction to optimally advise patients on anticipated outcomes. Due to both advanced cancer on presentation and comorbid conditions, only one-third of patients are ultimately considered candidates for surgical resection. Despite modern surgical, anesthetic, and postoperative techniques, there is still a perioperative mortality rate of 1-5%. Postoperative myocardial infarction is an important source of morbidity and mortality for those undergoing extensive lung resections, especially trans-pericardial pneumonectomies. Until surgery is suggested, preoperative evaluation of the cardiovascular system should be required for the existence of active heart disease (unstable angina, recent myocardial infarction, decompensated heart failure, arrhythmias, or valve defects).In addition to identifying cardiac risk factors, a preoperative assessment is incomplete without quantifying a patient's functional capacity. This can be achieved by the results of a formal stress test, measured in units of metabolic equivalents of task (MET). Geriatric assessment (GA) is a method used to collect information about the physical condition of elderly patients, which may be useful in estimating life expectancy and predicting treatment toxicity. GA includes an assessment of functional status, fatigue, cognitive function, mental health, nutritional status, the individual's ability to complete instrumental activities of daily living, comorbidities, social support, and the presence of geriatric syndromes. CONCLUSIONS. A thorough analysis of the results of diagnostic tests, referring to the functional evaluation of patients with advanced BPC and/or comorbidities, would allow the extension of surgical indications to obtain new results and increase over time the survival and quality of life of these patients.

Extensive Lung Resection for Nontuberculous Mycobacterial Lung Disease With Multilobar Lesions

Nontuberculous mycobacterial lung disease often spreads to multiple lobes, and extensive lung resection (ELR) is sometimes required to control the disease. The safety and feasibility of ELR for nontuberculous mycobacterial lung disease remain unclear, however. This retrospective study included patients with nontuberculous mycobacterial lung disease who underwent adjuvant lung resection. Characteristics were compared between patients who underwent ELR and those who underwent simple anatomic lung resection (SALR). The outcome data were analyzed by a Cox regression analysis. A total of 146 patients underwent ELR (n= 54) or SALR (n= 92). ELR was associated with a longer operative time (306 vs 237 minutes; P < .001) and higher incidence of prolonged air leak (17% vs 3.3%; P= .016) than SALR. Rates of mortality, sputum culture conversion (positive to negative), and microbiological recurrence did not differ markedly between the groups. In the multivariate analysis, ELR was not a significant risk factor for an unfavorable outcome after nontuberculous mycobacterial lung disease surgery (hazard ratio, 2.23; 95% confidence interval, 0.82-6.03; P= .11). ELR for nontuberculous mycobacterial lung disease has some drawbacks compared with SALR but seems as safe and feasible as SALR. ELR may provide improved disease control in some cases of nontuberculous mycobacterial lung disease with multilobar lesions.

Perioperative management in thoracic surgery

Thoracic surgery has undergone significant advances in recent years related to anesthetic and surgical techniques and the prevention and management of complications related to the procedure. This has allowed improvements in patient clinical outcomes in surgeries of this kind. Despite the above, thoracic surgery, especially related to pulmonary resection, is not without risk, and is associated to considerable morbidity and mortality. Fast track or enhanced recovery after anesthesia protocols, minimally invasive surgery, and intraoperative anesthetic management improve the prognosis and safety of thoracic surgery. Patients in the postoperative period of major thoracic surgery require intensive surveillance, especially the first 24–72h after surgery. Admission to the ICU is especially recommended in those patients with comorbidities, a reduced cardiopulmonary reserve, extensive lung resections, and those requiring support due to life-threatening organ failure. During the postoperative period, intensive cardiorespiratory monitoring, proper management of thoracic drainage, aggressive pain control (multimodal analgesia and regional anesthetic techniques), nausea and multimodal rehabilitation are key elements for avoiding adverse events. Medical complications include respiratory failure, arrhythmias, respiratory infections, atelectasis and thromboembolic lung disease. The most frequent surgical complications are hemothorax, chylothorax, bronchopleural fistula and prolonged air leakage. The multidisciplinary management of these patients throughout the perioperative period is essential in order to ensure the best surgical outcomes.

External validity of a model to predict postoperative atrial fibrillation after thoracic surgery.

A prediction model developed by Passman et al. stratifies patients' risk of postoperative atrial fibrillation (POAF) after major non-cardiac thoracic surgery using 3 simple factors (sex, age and preoperative resting heart rate). The model has neither undergone external validation nor proven to be relevant in current thoracic surgery practice. A retrospective single-centre analysis of all patients who underwent major non-cardiac thoracic surgery (2008-2017) with prospective documentation of incidence and severity of POAF was used for external validation of Passman's derivation sample (published in 2005 with 856 patients). The model calibration was assessed by evaluating the incidence of POAF and patients' risk scores (0-6). A total of 2054 patients were included. Among them, POAF occurred in 164 (7.9%), compared to 147 (17.2%) in Passman's study. Differences in our sample compared to Passman's sample included mean heart rate (75.7 vs 73.7 bpm, P < 0.001), proportion of patients with hypertension (46.1 vs 29.4%, P < 0.001), proportion of extensive lung resections, particularly pneumonectomy (6.1 vs 21%, P < 0.001) and proportion of minimally invasive surgeries (56.6% vs 0%). The model demonstrated a positive correlation between risk scores and POAF incidence (risk score 1.2% vs 6.16%). The POAF model demonstrated good calibration in our population, despite a lower overall incidence of POAF compared to the derivation study. POAF rates were higher among patients with a higher risk score and undergoing procedures with greater intrathoracic dissection. This tool may be useful in identifying patients who are at risk of POAF when undergoing major thoracic surgery and may, therefore, benefit from targeted prophylactic therapy.

ПРЕДРАСПОЛАГАЮЩИЕ ФАКТОРЫ РАЗВИТИЯ ФИБРИЛЛЯЦИИ ПРЕДСЕРДИЙ У ПАЦИЕНТОВ ПОСЛЕ АНАТОМИЧЕСКОЙ РЕЗЕКЦИИ ЛЕГКИХ

Atrial fibrillation (AF) remains to be one of the most common complications that occur after thoracic surgery; its frequency makes from 4 to 37%. This type of complication can significantly extend the recovery period for the patients after anatomic lung resection and increase the short-term and long-term mortality. Subjects and methods . Data of 183 patients who underwent extensive anatomic lung resections due to malignant neoplasms were retrospectively analyzed. The following was evaluated: the impact of surgery approach (thoracotomy or VATS) and the type of anatomic lung resection, peri-operative fluid balance and severity of pain syndrome as per Visual Analogue Scale on the incidence of AF. Statistical analysis was performed using Student's t-test, non-parametric χ2 test and Mann – Whitney test, as well as a multidimensional logistic regression with standardization of indicators and odds ratio calculation. Results . In the early post-operative period, AF developed in 40 patients. It was found out that with increasing age, the rate of intra-operative infusion and positive fluid balance during the first day of the post-operative period, the risk of post-operative AF went up in thoracic patients.

Thoracoscopic (video-assisted thoracoscopic surgery) pneumonectomy, technical details and literature review

It is not known if the benefits of thoracoscopic approaches over thoracotomy for lobar and sublobar resection for early stage non-small cell lung carcinoma (NSCLC) are realized for patients undergoing more extensive lung resection such as pneumonectomy. Approaching whole lung resection by video-assisted thoracoscopic surgery (VATS) has remained less common, therefore little evidence exists regarding the potential advantages of performing pneumonectomy by VATS. Despite this, continued efforts to decrease surgical morbidity and mortality associated with pneumonectomy, along with increasing surgeon experience, have led to reports for VATS pneumonectomy from select centers. The following represents a description of the important technical aspects, as well as a review of pertinent literature, largely from case series and single institution experiences regarding thoracoscopic approaches to pneumonectomy.

Adjuvant chemotherapy after resection of N1 non-small cell lung cancer: differential impact of new evidence on physician and patient decisions.

Adjuvant cisplatin-based chemotherapy (ACT) after resection of stages II-IIIA non-small cell lung cancer (NSCLC) modestly increased survival in several clinical trials. This study evaluated the subsequent impact of those trials on ACT use in clinical practice. Patients who underwent lobectomy or more extensive lung resection without induction chemotherapy for pathologically confirmed N1 positive NSCLC between 2000 and 2012 were reviewed. Referrals to medical oncology, oncologist recommendations for ACT, and initiation of ACT were evaluated. Because major trials supporting ACT were published in 2004 and 2005, analysis was stratified into two eras: 2000-2005 and 2006-2012. During the study period, 272 patients met inclusion criteria (110 in the 2000-2005 cohort, 162 in the 2006-2012 cohort). Referrals to medical oncology increased from 74.5% (n=82) in the 2000-2005 cohort to 90.1% (n=146) in the 2006-2012 cohort (P=0.002). Due to lack of referral or missed appointments, 35.5% (n=39) of the 2000-2005 patients and 17.9% (n=32) of the 2006-2012 patients did not have a documented conversation with an oncologist regarding ACT. The proportion of patients recommended for ACT increased from 61% (n=50) to 81.5% (n=119) between the eras (P<0.001). Of patients recommended for chemotherapy, 14% (7/50) in 2000-2005 and 13.4% (16/119) in 2006-2012 declined ACT (P=0.666). Publication of supporting evidence increased recommendations for ACT but did not change the percentage of patients who ultimately agreed to receive ACT. Additional research is needed to better understand patient decision-making in this situation.

Validation of a Scoring System to Predict Recurrence of Resected Solitary Fibrous Tumors of the Pleura

Solitary fibrous tumors of the pleura (SFTPs) are infrequent neoplasms with no standardized criteria to predict risk of recurrence after curative surgery. The aim of the present study is to validate a recently proposed recurrence score in a large European cohort of patients with SFTP. Validation of a previously published scoring system was assessed in a population of 113 patients who underwent complete resection of SFTPs. Patients were scored according to the pleural origin, morphology, size, hypercellularity, presence of necrosis or hemorrhage, and number of mitoses in their SFTPs. Receiver operating characteristic curves were plotted for the score. Time to recurrence analysis was performed using the Kaplan-Meier and Cox proportional hazards methods. After a mean follow-up of 13.2 ± 7.3 years, there were nine recurrences (8.0%). Score performance to predict recurrence was as follows: sensitivity = 78%, specificity = 74%, positive likelihood ratio = 3.0, and negative likelihood ratio = 0.3. A cutoff of 3 points was used to classify 79 patients (69.9%) at low risk and 34 patients (30.1%) at high risk for recurrence. A high-risk classification was significantly associated with more recurrences during follow-up (P = .004), worse overall survival (P = .0008), more extensive lung resections (P = .001), and the use of adjuvant therapies (P = .009). The present score outperformed England's criteria (P = .049) and de Perrot classification (P < .001) when predicting SFTP recurrence. The proposed scoring system, which combines common clinical and histologic features of resected SFTPs, remains predictive of recurrence in a separate patient population. The simple score may guide the postoperative surveillance of this uncommon tumor.

Review of the evidence supports role for routine prophylaxis against postoperative supraventricular arrhythmia in patients undergoing pulmonary resection: Table 1:

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'Is there an indication for routine prophylaxis against postoperative supraventricular arrhythmia in patients undergoing pulmonary resection surgery?' Altogether almost 150 papers were found as a result of the reported search, of which 14 represented the best evidence to reach conclusions regarding the issues of interest for this review. The major outcome of interest that was investigated was the incidence of supraventricular arrhythmia (SVA), notably atrial fibrillation (AF). The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study weakness of the papers were tabulated. Current guidance from the Society of Thoracic Surgeons (STS) supports the use of diltiazem and amiodarone in most patients undergoing major pulmonary resection. Robust data from a large randomized, controlled trial (RCT) showed a reduction from 25 to 15% in the incidence of clinically significant atrial arrhythmia with diltiazem; P<0.03. Moreover, numerous RCTs have shown that there is a clear benefit with the use of amiodarone in reducing the incidence of postoperative SVA. Of note, one prospective clinical trial randomized 242 patients into a treatment group with amiodarone (n = 122) and a placebo group (n = 120). The incidence of postoperative AF was reduced from 32 to 9% in the active arm; P < 0.001. The risk of acute lung injury with amiodarone has not been substantiated further in more recent clinical trials and has in fact been shown to be safe. The STS guidelines do, however, advise against the use of amiodarone in extensive lung resection such as pneumonectomy. We conclude that there is an indication for routine prophylaxis against postoperative supraventricular arrhythmia in patients undergoing pulmonary resection. However, further data are needed to ascertain the impact of said anti-arrhythmic medications on the length of postoperative hospital stay, intensive care unit stay and cost. Those patients deemed high-risk need to be promptly identified, so the anti-arrhythmic therapy can be tailored to the cohort thus optimizing on cost and safety.

Estimation of Extravascular Lung Water During and After Extensive Thoracic Interventions

Background. Postoperative lung injury is a cause of most fatal outcomes after extensive lung resections. Death rates due to postpneumonectomy pulmonary edema have remained unchanged within the past 20 years and are currently tending to 100%. Objective: to make prolonged lung edema monitoring in patients after extensive thoracic interventions. Subjects and methods. The observational study covered 27 patients who had undergone pneumonectomy (PE) (n=16) or lung resection (n=11). Invasive monitoring by the PiCCOplus system was performed to examine the systemic and pulmonary hemodynamics of all the patients during surgery and within 48 postoperative hours. Results. PE rather than lung resection was accompanied by a significant reduction in the extravascular lung water index (EVLWI). Most patients who had undergone PE were found to have a subclinical increase in EVLWI 36-48 hours after termination of the intervention. Conclusion. In this observational clinical study, isolated thermodilution showed an immediate decrease in EVLWI after PE and its increase at 36—48 postoperative hours. Lobar or segmental interventions failed to cause significant changes in EVLWI in the perioperative period. Key words: pneumonectomy, lung resection, lung edema, extravascular lung water, acute lung injury.

Ruptured pulmonary artery aneurysm: a surgical emergency

Idiopathic pulmonary artery aneurysm rupture was diagnosed in a 79-year-old man who presented with a dry cough. He was considered unlikely to tolerate extensive pulmonary artery reconstruction or lung resection; hence, he was salvaged by timely ligation of the distal pulmonary artery at the origin of the aneurysm.

Progressive adaptation in regional parenchyma mechanics following extensive lung resection assessed by functional computed tomography

In adult canines following major lung resection, the remaining lobes expand asymmetrically, associated with alveolar tissue regrowth, remodeling, and progressive functional compensation over many months. To permit noninvasive longitudinal assessment of regional growth and function, we performed serial high-resolution computed tomography (HRCT) on six male dogs (∼9 mo old, 25.0 ± 4.5 kg, ±SD) at 15 and 30 cmH(2)O transpulmonary pressure (Ptp) before resection (PRE) and 3 and 15 mo postresection (POST3 and POST15, respectively) of 65-70% of lung units. At POST3, lobar air volume increased 83-148% and tissue (including microvascular blood) volume 120-234% above PRE values without further changes at POST15. Lobar-specific compliance (Cs) increased 52-137% from PRE to POST3 and 28-79% from POST3 to POST15. Inflation-related parenchyma strain and shear were estimated by detailed registration of corresponding anatomical features at each Ptp. Within each lobe, regional displacement was most pronounced at the caudal region, whereas strain was pronounced in the periphery. Regional three-dimensional strain magnitudes increased heterogeneously from PRE to POST3, with further medial-lateral increases from POST3 to POST15. Lobar principal strains (PSs) were unchanged or modestly elevated postresection; changes in lobar maximum PS correlated inversely with changes in lobar air and tissue volumes. Lobar shear distortion increased in coronal and transverse planes at POST3 without further changes thereafter. These results establish a novel use of functional HRCT to map heterogeneous regional deformation during compensatory lung growth and illustrate a stimulus-response feedback loop whereby postresection mechanical stress initiates differential lobar regrowth and sustained remodeling, which in turn, relieves parenchyma stress and strain, resulting in progressive increases in lobar Cs and a delayed increase in whole lung Cs.

Surgical Management of Congenital Cystic Lung Malformations in Older Patients

Congenital cystic malformations of the lung often go unrecognized in childhood. It is controversial whether surgical management in older patients requires more extensive lung resection. The aim of our study was to analyze the outcomes of surgical management in older patients. A retrospective review was made of all patients treated surgically for congenital cystic lung lesion between 1994 and 2009. One hundred two patients (65 women, 37 men) underwent surgery for a congenital cystic lung lesion. Median age was 47 years (range, 4 to 80 years). Surgical approach was through a thoracotomy in 70 patients, thoracoscopy in 21, sternotomy in 5, mediastinoscopy in 4, and laparoscopy and cervical in 1 each. Simple enucleation of the cyst was done in 67 patients, but 35 required more extensive pulmonary resection: lobectomy in 20, segmentectomy in 8, wedge in 6, and bilobectomy in 1. There was no significant difference between these groups with respect to age, sex, or postoperative outcomes. Univariate analysis revealed pneumonia, complex cysts, male sex, left-sided lesions, and bronchogenic cysts as predictors of a concomitant pulmonary resection being necessary during removal of the lesions. In a multivariable model, pneumonia and bronchogenic cysts persisted as predictors of the need for a more extensive pulmonary resection. A cystic malformation can be resected by simple resection, but in approximately one third of cases, a more extensive pulmonary resection is required. Patients with bronchogenic cysts who present with recurrent pneumonia are more likely to require a more extensive pulmonary resection.

Noninvasive quantification of heterogeneous lung growth following extensive lung resection by high-resolution computed tomography

To quantify the in vivo magnitude and distribution of regional compensatory lung growth following extensive lung resection, we performed high-resolution computed tomography at 15- and 30-cmH(2)O transpulmonary pressures and measured air and tissue (including microvascular blood) volumes within and among lobes in six adult male foxhounds, before and after balanced 65% lung resection ( approximately 32% removed from each side). Each lobe was identified from lobar fissures. Intralobar gradients in air and tissue volumes were expressed along standardized x,y,z-coordinate axes. Fractional tissue volume (FTV) was calculated as the volume ratio of tissue/(tissue + air). Following resection compared with before, lobar air and tissue volumes increased 1.8- to 3.5-fold, and whole lung air and tissue volumes were 67 and 90% of normal, respectively. Lobar-specific compliance doubled post-resection, and whole lung-specific compliance normalized. These results are consistent with vigorous compensatory growth in all remaining lobes. Compared with pre-resection, post-resection interlobar heterogeneity of FTV, assessed from the coefficient of variation, decreased at submaximal inflation, but was unchanged at maximal inflation. The coefficient of variation of intralobar FTV gradients changed variably due to the patchy development of thickened pleura and alveolar septa, with elevated alveolar septal density and connective tissue content in posterior-caudal and peripheral regions of the remaining lobes; these areas likely experienced disproportional mechanical stress. We conclude that HRCT can noninvasively and quantitatively assess the magnitude and spatial distribution of compensatory lung growth. Following extensive resection, heterogeneous regional mechanical lung strain may exceed the level that could be sustained solely by existing connective tissue elements.

Predictors of Prolonged Postoperative Endotracheal Intubation in Patients Undergoing Thoracotomy for Lung Resection

The aim of this study was to identify predictors of delayed endotracheal extubation defined as the need for postoperative ventilatory support after open thoracotomy for lung resection. An observational cohort investigation. A tertiary referral center. The study population consisted of 2,068 patients who had open thoracotomy for pneumonectomy, lobectomy, or segmental lung resection between January 1996 and December 2005. Not applicable. Preoperative and intraoperative variables were collected concurrently with the patient's care. Risk factors were identified using logistic regression with stepwise variable selection procedure on 1,000 bootstrap resamples, and a bagging algorithm was used to summarize the results. Intraoperative red blood cell transfusion, higher preoperative serum creatinine level, absence of a thoracic epidural catheter, more extensive surgical resection, and lower preoperative FEV(1) were associated with an increased risk of delayed extubation after lung resection. Most predictors of delayed postoperative extubation (ie, red blood cell transfusion, higher preoperative serum creatinine, lower preoperative FEV(1), and more extensive lung resection) are difficult to modify in the perioperative period and probably represent greater severity of underlying lung disease and more advanced comorbid conditions. However, thoracic epidural anesthesia and analgesia is a modifiable factor that was associated with reduced odds for postoperative ventilatory support. Thus, the use of epidural analgesia may reduce the need for post-thoracotomy mechanical ventilation.

Shifting sources of functional limitation following extensive (70%) lung resection

We previously found that, following surgical resection of approximately 58% of lung units by right pneumonectomy (PNX) in adult canines, oxygen-diffusing capacity (Dl(O(2))) fell sufficiently to become a major factor limiting exercise capacity, although the decline was mitigated by recruitment, remodeling, and growth of the remaining lung units. To determine whether an upper limit of compensation is reached following the loss of even more lung units, we measured pulmonary gas exchange, hemodynamics, and ventilatory power requirements in adult canines during treadmill exercise following two-stage resection of approximately 70% of lung units in the presence or absence of mediastinal distortion. Results were compared with that in control animals following right PNX or thoracotomy without resection (Sham). Following 70% lung resection, peak O(2) uptake was 45% below normal. Ventilation-perfusion mismatch developed, and pulmonary arterial pressure and ventilatory power requirements became markedly elevated. In contrast, the relationship of Dl(O(2)) to cardiac output remained normal, indicating preservation of Dl(O(2))-to-cardiac output ratio and alveolar-capillary recruitment up to peak exercise. The impairment in airway and vascular function exceeded the impairment in gas exchange and imposed the major limitation to exercise following 70% resection. Mediastinal distortion further reduced air and blood flow conductance, resulting in CO(2) retention. Results suggest that adaptation of extra-acinar airways and blood vessels lagged behind that of acinar tissue. As more lung units were lost, functional compensation became limited by the disproportionately reduced convective conductance rather than by alveolar diffusion disequilibrium.