Feasibility experimental study on plugging leakage in goaf based on two-phase foam.

Air leakage in goaf often leads to coal spontaneous combustion (CSC), which not only directly affects the safety production of mines but also causes significant environmental damage. Therefore, effectively sealing the airflow in goaf is crucial for preventing CSC. Feasibility experiments on using two-phase foam to seal air leakage in goaf were conducted, leveraging the advantages of large flow rate, wide diffusion range, and good accumulation characteristics of two-phase foam. The research results indicate that continuous injection of foam into loose media with maintained ventilation can completely seal the air leakage, with the foam capable of withstanding wind pressures of nearly 600 Pa. When the foam is used for one-time sealing with a length of 2 m, it remains effective for 60 min, and the sealing effectiveness improves with longer distances sealed against air leakage. Numerical simulation analysis and field measurements of airflow leakage in mine working faces reveal that effectively sealing the airflow passage in the goaf behind the corner of the return airway is crucial for preventing CSC. Two methods are proposed for sealing external airflow during coal mining: foam injection using a point drilling method near the heading and an incremental buried pipe injection method. Finally, the feasibility of two-phase foam sealing technology for goaf airflow leakage is analyzed from multiple perspectives including sealing effectiveness, practicality, economy, foaming process, and engineering implementation. The research findings provide new insights into goaf sealing technology, aiding in addressing safety and environmental issues caused by spontaneous combustion in goaf areas.

Risk factor evaluation of cuff pressure of >30 cmH2O to stop air leakage during mechanical ventilation: A prospective observational study.

AIM: The commonly recommended endotracheal tube cuff pressure is 20-30 cmH2O. However, some patients require a cuff pressure of >30 cmH2O to prevent air leakage. The study aims to determine the risk factors that contribute to the endotracheal tube cuff pressure of >30 cmH2O to prevent air leakage. DESIGN: A multi-centre prospective observational study. METHODS: Eligible patients undergoing mechanical ventilation in the intensive care unit of three hospitals between March 2020 and July 2022 were included. The endotracheal tube cuff pressure to prevent air leakage was determined using the minimal occlusive volume technique. The patient demographics and clinical information were collected. RESULTS: A total of 284 patients were included. Among these patients, 55 (19.37%) patients required a cuff pressure of >30 cmH2O to prevent air leakage. The multivariate logistic regression results revealed that the surgical operation (odds ratio [OR]: 8.485, 95% confidence interval [CI]: 1.066-67.525, p = 0.043) was inversely associated with the endotracheal tube cuff pressure of >30 cmH2O, while the oral intubation route (OR: 0.127, 95% CI: 0.022-0.750, p = 0.023) and cuff inner diameter minus tracheal area (OR: 0.949, 95% CI: 0.933-0.966, p < 0.001) were negatively associated with the endotracheal tube cuff pressure of >30 cmH2O. Therefore, a significant number of patients require an endotracheal tube cuff pressure of ＞30 cmH2O to prevent air leakage. Several factors, including the surgical operation, intubation route, and difference between the cuff inner diameter and tracheal area at the T3 vertebra, should be considered when determining the appropriate cuff pressure during mechanical ventilation.

Re-appraisal of bronchus-first right upper lobectomy as an alternative routine procedure.

OBJECTIVES: Postoperative air leakage is a major complication of lung resection, particularly right upper lobectomy. However, various surgical procedures can reduce postoperative complications and shorten the drainage period. The current study aimed to analyse the utility of bronchus-first right upper lobectomy as an alternative routine procedure. METHODS: We retrospectively analysed the data of 225 (53.7%) patients who underwent bronchus-first right upper lobectomy and 194 (46.3%) patients who underwent the conventional bronchus-last right upper lobectomy at our institution from 2015 to 2022. In patients with incomplete fissures who underwent bronchus-first right upper lobectomy, the bronchus was dissected 1st, followed by the pulmonary artery and vein, and then, the interlobar fissure was divided. We compared the outcomes of 2 procedures and analysed the surgical utility of bronchus-first right upper lobectomy. RESULTS: The surgical outcomes and postoperative morbidity comparing bronchus-first and bronchus-last procedure were as follows: median operation time (min) 103/126 (P < 0.001), median bleeding amount (ml) 28/55 (P = 0.003), incomplete lobulation rate (%) 35.1/24.2 (P = 0.02), incidence of prolonged air leakage (%) 2.2/3.1 (P = 0.76) and rate of fellow surgeon's operation (%) 28.0/4.6 (P < 0.001). The procedure was associated with a decreased incidence of prolonged air leakage. The 4-year overall survival rates did not significantly differ between the 2 groups (P = 0.24). CONCLUSIONS: Bronchus-first right upper lobectomy can prevent postoperative air leakage in patients with incomplete fissure. Additionally, as an alternative routine procedure, it is associated with a shorter surgical duration and a lower volume of blood loss regardless of interlobar fissure and operator's experience.

Effectiveness of autologous fibrin glue in preventing post-thoracotomy air leaks: a randomized controlled trial.

Introduction: Post-thoracotomy air leaks remain a significant challenge in thoracic surgery. Aim: This randomized controlled trial assessed the efficacy of autologous fibrin glue in reducing air leaks following thoracotomy procedures. Material and methods: Conducted as a single-center, single-blind, randomized clinical trial, the study enrolled adult patients undergoing lung resection or decortication at a thoracic surgery clinic. Participants were randomly assigned to either the intervention group, receiving autologous fibrin glue application during surgery, or the control group, undergoing standard surgical procedures without glue application. Key inclusion criteria were adult patients undergoing elective thoracotomy for lung resection or decortication, while exclusion criteria included patients with severe comorbidities or contraindications to fibrin glue. Results: A total of 40 patients were enrolled and randomized equally to the two groups. The group treated with autologous fibrin glue demonstrated a significant reduction in the duration of air leakage and chest tube drainage, along with a shorter hospital stay, compared to the control group. There were no statistically significant differences in postoperative complications between the groups. Conclusions: The application of autologous fibrin glue during thoracotomy procedures significantly reduces postoperative air leaks and hospitalization duration without increasing complication rates. This finding suggests a beneficial role of fibrin glue in thoracic procedures requiring lung resection or decortication.

Maximum resistance pressure at the time of lung tissue rupture after porcine lung transection using automatic linear staplers with different reinforcement methods.

PURPOSES: Polyglycolic acid (PGA) sheets, fibrin glue, and staple line reinforcement are frequently used to prevent air leakage during lung resection. However, the optimal staple-line reinforcement method remains unclear. METHODS: Cranial lung lobes of pigs were used to evaluate different staple line reinforcement methods (n = 6). Ventilator-assisted manometry was used to measure the maximum resistance pressure at the time of rupture of the lung tissue after stapling. RESULTS: The mean maximum resistance pressures at the time of lung tissue rupture after using the stapler alone, stapler with PGA sheet and fibrin glue, and stapler with reinforcement were 38.0 cmH2O, 51.3 cmH2O, and 62.7 cmH2O, respectively. A significant increase in the maximum resistance pressure was observed with stapler reinforcement (P < 0.001), while the differences between the other groups were not statistically significant (P = 0.055, P = 0.111). A histological assessment revealed disruption of alveolar structures near the needle-stitching site in the stapler alone, and in the stapler with PGA sheet and fibrin glue groups. Pleural rupture near the staple line was observed in the stapler with reinforcement group. CONCLUSIONS: The maximum resistance pressure before air leakage was significantly higher when using a stapler with reinforcement than when using a stapler alone.

Safety and efficacy of new staple-line reinforcement in lung resection: a prospective study of 48 patients.

PURPOSE: To evaluate the safety and efficacy of new staple-line reinforcement (SLR) in pulmonary resection through a prospective study and to compare the results of this study with historical control data in an exploratory study. METHODS: The subjects of this study were 48 patients who underwent thoracoscopic lobectomy. The primary endpoint was air leakage from the staple line. The secondary endpoints were the location of air leakage, duration of air leakage, and postoperative pulmonary complications. RESULTS: The incidence of intraoperative air leakage from the staple line was 6.3%. Three patients had prolonged air leakage as a postoperative pulmonary complication. No malfunction was found in patients who underwent SLR with the stapling device. When compared with the historical group, the SLR group had a significantly lower incidence of air leakage from the staple line (6.3% vs. 28.5%, P < 0.001) and significantly shorter indwelling chest drainage time (P = 0.049) and length of hospital stay (P < 0.001). CONCLUSIONS: The use of SLR in pulmonary resection was safe and effective. When compared with conventional products, SLR could control intraoperative air leakage from the staple line and shorten time needed for indwelling chest drainage and the length of hospital stay.

A comparative study of surgical outcomes for secondary spontaneous pneumothorax and the postoperative survival prognostic factor: interstitial vs. non-interstitial pneumonia.

PURPOSE: To investigate the surgical outcomes and postoperative survival prognostic factors of intractable secondary spontaneous pneumothorax. METHODS: A total of 95 patients who underwent thoracoscopic surgery for intractable secondary spontaneous pneumothorax between April 2010 and March 2020 were included in this study. These patients were classified into interstitial pneumonia and non-interstitial pneumonia groups, and a comparative study was performed on surgical outcomes and postoperative survival prognostic factors. RESULTS: There was no difference in the 1-year overall survival rate between the two groups. However, the 3-year overall survival rate was significantly lower in the interstitial pneumonia group than in the non-interstitial pneumonia group. The differences in short-term surgical outcomes (persistent air leakage, postoperative complications, etc.) were not significant between the two groups. Univariate analysis revealed that the drainage period, the development of postoperative complications, and recurrence were significant independent postoperative survival prognostic factors for all cases. Postoperative complications were the only associated postoperative survival prognostic factor for interstitial pneumonia pneumothorax in the multivariate analysis. CONCLUSION: The development of postoperative complications can cause poor postoperative survival prognosis of intractable secondary spontaneous pneumothorax due to interstitial pneumonia.

Effectiveness of pleurodesis for postoperative air leaks after lung resection.

BACKGROUND: Pleurodesis is often performed for air leaks; however, the ideal materials and timing of the procedure remain controversial. We investigated the efficacy of pleurodesis using different materials and timing. METHODS: We retrospectively reviewed 913 consecutive patients who underwent segmentectomy or lobectomy for non-small cell lung cancer between 2014 and 2021. Pleurodesis efficacy was assessed on the day of chest tube removal. RESULTS: Eighty-six patients (9%) underwent pleurodesis for postoperative air leaks. Pleurodesis was performed on a median of postoperative day (POD) 5. Talc was the most frequently used material (n = 52, 60%), followed by autologous blood patches (n = 20, 23%), OK-432 (n = 12, 14%), and others (n = 2, 2%). No difference existed in the number of days from initial pleurodesis to chest tube removal among the three groups (talc, 3 days; autologous blood patch, 3 days; OK-432, 2 days; P = 0.55). No difference in patient background, except for sex, was observed between patients who underwent pleurodesis within 4 PODs and those who underwent pleurodesis on POD 5 or later. Drainage time was significantly shorter in patients who underwent pleurodesis within 4 PODs (median, 7 vs. 9 days; P = 0.004). CONCLUSIONS: The efficacies of autologous blood patch, talc, and OK-432 would be considered comparable and early postoperative pleurodesis could shorten drainage time. Prospective studies are required.

Postoperative management using a digital drainage system for massive air leakage after pulmonary resection.

PURPOSE: To elucidate clinical outcomes using a digital drainage system (DDS) for massive air leakage (MAL) after pulmonary resection. METHODS: A total of 135 consecutive patients with pulmonary resection air leakage of > 100 ml/min on the DDS were evaluated retrospectively. In this study, MAL was defined as ≥ 1000 ml/min on the DDS. We analyzed the clinical characteristics and surgical outcomes of patients with MAL compared with non-MAL (101-999 ml/min). Using the DDS data, the duration of the air leak was plotted with the Kaplan‒Meier method and compared using the log-rank test. RESULTS: MAL was detected in 19 (14%) patients. The proportions of heavy smokers (P = 0.04) and patients with emphysematous lung (P = 0.03) and interstitial lung disease (P < 0.01) were higher in the MAL group than in the non-MAL group. The MAL group had a higher persistence rate of air leakage at 120 h after surgery than the non-MAL group (P < 0.01) and required significantly more frequent pleurodesis (P < 0.01). Drainage failure occurred in 2 (11%) and 5 (4%) patients from the MAL and non-MAL groups, respectively. Neither reoperation nor 30-day surgical mortality was observed in patients with MAL. CONCLUSIONS: MAL was able to be treated conservatively without surgery using the DDS.

Effect of hydrocolloid dressings on preventing air leakage when applying negative pressure wound therapy to the perineum, buttocks, and sacrococcygeal region.

Maintaining a vacuum when applying negative pressure wound therapy (NPWT) is the key to its function, which is a challenge in the perineum, buttocks, and sacrococcygeal region. A retrospective cohort study was conducted to assess the effect of hydrocolloid dressings on preventing air leakage when applying NPWT in these regions. There were 61 patients in Group A (without the aid of hydrocolloid dressings) and 65 patients in Group B (with the aid of hydrocolloid dressings). The hydrocolloid dressing-assisted NPWT significantly reduced the incidence of air leakage compared with conventional NPWT placement (24.6% vs. 7.7%; risk ratio, 3.20; 95% confidence interval, 1.24-8.27; p = 0.009), while decreasing the number of open NPWT applications (2.2 vs. 1.7; difference, 0.43; 95% confidence interval, 0.19-0.66; p < 0.001), shortening hospital stays (20.1 vs. 16.1; difference, 4.07; 95% confidence interval, 1.68-6.46; p = 0.01), and reducing the incidence of adverse skin events (18.0% vs. 4.6%; risk ratio, 3.91; 95% confidence interval, 1.14-13.34; p = 0.017). These findings support the routine use of hydrocolloid dressing-assisted NPWT placement in the perineum, buttocks, and sacrococcygeal region.

Which bioabsorbable sheet is optimal for combined application with fibrin sealant against alveolar air leakage?

Background: There are few basic comparative data on the sealing effect of various bioabsorbable sheets in combination with fibrin sealant (FS), which is a more effective tool for the control of alveolar air leakage than the single use of FS alone. The objective of this study was to investigate which bioabsorbable sheet had the best sealing effect against alveolar air leakage when used in combination with FS, in terms of material quality, weaving pattern, and/or thickness. Methods: Standardized 20 mm × 30 mm pleural defects were covered with three pieces of the following sheets using the Rub + Soak B technique in an ex vivo porcine lung model. Seal-breaking burst pressure (SBBP) was compared between groups. Experiment 1: 0.15 mm-thick (Group 1), 0.3 mm-thick (Group 2) and 0.5 mm-thick (Group 3) non-woven polyglycolic acid (PGA) felt were compared. Experiment 2: 0.15 mm-thick non-woven PGA felt (Group 1), 0.15 mm-thick meshed oxidised regenerated cellulose (ORC) (Group 4); 0.11 mm-thick woven PGA (Group 5) and 0.18 mm-thick knitted PGA (Group 6) were compared. Experiment 3: TachoSil® alone (Group 7), TachoSil® combined with FS (Group 8) and 0.15 mm-thick non-woven PGA felt (1 piece) (Group 9) were compared. Results: In Experiment 1, SBBP was significantly higher in Group 1 than in Group 3. The SBBP in Group 2 was significantly higher than that in Group 3. In Experiment 2, SBBP in Group 4 was significantly lower than that in Groups 1, 5, and 6. In Experiment 3, SBBP in Group 7 was significantly lower than that in Groups 8 and 9. Conclusions: Regarding the sheet thickness of PGA felt, the 0.15 mm was the most effective. Regarding the material quality, the ORC was the least suitable. TachoSil® combined with FS was comparable to the most effective 0.15 mm-thick non-woven PGA felt.

A retrospective analysis of treatment selection and risk factors of treatment failure and recurrence in patients with spontaneous pneumothorax.

Background: Conservative observation with/without oxygen supplementation, aspiration, or tube drainage is selected as an initial treatment for spontaneous pneumothorax. In this study, we examined the efficacy of initial management for cessation of air leak and prevention of recurrence, with consideration of the degree of lung collapse. Methods: Spontaneous pneumothorax in patients who underwent initial management in our institute between January 2006 and December 2015 were included in this retrospective, single-institutional study. Multivariate analyses were conducted to identify risk factors related to the treatment failure after initial treatment and those related to ipsilateral recurrence after last treatment. Results: Of 668 episodes of 522 patients, 198 events were initially treated by observation, 22 by aspiration, and 448 by tube drainage. Successive outcome for cessation of air leak in initial treatment was achieved in 170 (85.9%), 18 (81.8%), and 289 (64.5%) events, respectively. In the multivariate analysis for predicting failure after first treatment, previous episode of ipsilateral pneumothorax [odds ratio (OR) 1.9; 95% confidence interval (CI): 1.3-2.9; P<0.01], high degree of lung collapse (OR 2.1; 95% CI: 1.1-4.2; P=0.032), and bulla formation (OR 2.6; 95% CI: 1.7-4.1; P<0.0001) were the significant risk factors for treatment failure. Recurrence of ipsilateral pneumothorax was observed in 126 (18.9%) cases: 18 of 153 cases (11.8%) in the observation group, 3 of 18 cases in the aspiration group (16.7%), 67 of 262 cases in the tube drainage group (25.6%), 15 of 63 cases in the pleurodesis group (23.8%), and 23 of 170 cases in the surgery group (13.5%). In the multivariate analysis for predicting recurrence, previous episode of ipsilateral pneumothorax was a significant risk factor [hazard ratio (HR) 1.8; 95% CI: 1.2-2.5; P<0.001]. Conclusions: Predictive factors for failure after initial treatment were recurrence of ipsilateral pneumothorax, high degree of lung collapse, and radiological evidence of bullae. The predictive factor for recurrence after the last treatment was the previous episode of ipsilateral pneumothorax. Observation was superior to tube drainage in success rate to cease air leak and recurrence rate, although this effect was not statistically significant.

The role of new staplers in reducing the incidence of air leak.

Surgical staplers play an important role in the contemporary minimally invasive thoracic surgery including resection of lung tissue. However, staple line failure resulting in postoperative air leaks is a common complication after lung surgery, that if persist more than five days are defined as prolonged air leaks (PALs). PALs are associated with increased length of stay, patient morbidity and mortality, and hospital costs. To reduce the incidence of PALs, stapler devices underwent in the last years ongoing development aimed at improving device-to-tissue interaction. This clinical practice review explores the most important aspects of the evolution of surgical staplers, based on the review of the available literature. Modern staple cartridges entail small bumps to engage tissue and minimize tissue movement during compression and firing. Staplers with graduated staple heights are advocated to generate less stress on tissue during compression and clamping, thus affording greater perfusion into the staple line. However, air leaks may occur from an appropriate staple line with complete pleural coverage and perfusion due to enlarged staple canals after lung inflation, particularly in case of emphysema. To buttress staple line, thus prevent air leaks in high-risk patients, several types of tissue coverage (bovine pericardium, polytetrafluoroethylene, knitted calcium alginate, bioabsorbable polyglycolic acid) have been successfully developed in the last years. Finally, the most advanced stapler technology is represented by the new energy powered staplers, able to eliminate the manual firing force, monitor tissue compression during firing, and making automatic adjustments to optimize the staple line.

A Study of Aluminum Honeycomb Structures under Dynamic Loading, with Consideration Given to the Effects of Air Leakage.

Aluminum honeycomb structures are used in the construction of protective materials due to the positive relationship between their mass and their energy-absorbing properties. Applying such materials in the construction of large machinery, such as military vehicles, requires the development of a new method of finite element modeling, one that considers conditions with high strain rates, because a material model is currently lacking in the available simulation software, including LS-DYNA. In the present study, we proposed and verified a method of numerically modeling honeycomb materials using a simplified Y element. Results with a good level of agreement between the full core model and the Y element were achieved. The obtained description of the material properties was used in the subsequent creation of a homogeneous model. In addition, we considered the influence of increases in pressure and the leakage of the air entrapped in the honeycomb cells. As a result, we were able to attain a high level of accuracy regarding the stress values across the entire range of progressive failure, from the loss of stability to full core densification, and across a wide range of strain rates.

[Diagnosis and treatment of bronchopleural fistula after anatomical lung resections]. / Khirurgiya bronkhoplevral'nogo svishcha posle anatomicheskikh rezektsii legkikh.

OBJECTIVE: To assess the factors causing air leakage after anatomical lung resections and present a rational tactical approach for timely establishing the cause and level of bronchial fistula. MATERIAL AND METHODS: We analyzed 723 patients who underwent anatomical lung resection (pneumonectomy - 136 patients, anatomical lobectomy and segmentectomy - 513, video-assisted anatomical resection - 74 patients). RESULTS: In 506 (69.9%) cases, complete lung inflation after surgery was observed within 24-48 hours. Persistent air discharge for more than 3 days was observed in 141 (19.5%) patients. Prolonged air leakage for more than 7 postoperative days occurred in 50 (6.9%) patients. Air discharge for more than 10 days was considered abnormal and observed in 20 (2.8%) patients. Redo surgeries were performed in 49 patients with bronchopleural fistula at the level of segmental bronchi. Forty-two patients after primary thoracoscopy and 6 ones after primary thoracotomy underwent video-assisted resection of the lung with bronchopleural fistula after previous surgery. In 11 patients, re-thoracotomy was performed: middle lobectomy after previous right-sided upper lobectomy in 2 patients, lung resection after previous segmentectomy in 8 cases and atypical resection of bulla after previous right-sided lower lobectomy in 1 case. CONCLUSION: Surgical approach for persistent postoperative air leakage involves various surgical interventions. The best option is minimally invasive thoracoscopic procedure. This method is valuable to visualize bronchopleural fistula, eliminate air leakage, additionally reinforce pulmonary suture and perform targeted adequate drainage of the pleural cavity.

Airtightness evaluation of Canadian dwellings and influencing factors based on measured data and predictive models.

The airtightness of buildings has a significant impact on buildings' energy efficiency, maintenance and occupant comfort. The main goal of this study is to provide an evaluation of the air leakage characteristics of dwellings in different regions in Canada. This study evaluated the key influencing factors on airtightness performance based on a large set of measured data (73,450 dwellings located in Canada with 11 measurement parameters for each). Machine learning models based on multivariate regression (MVR) and Random Forest Ensemble (RFE) were developed to predict the air leakage value. The RFE model, which shows better results than MVR, was used to evaluate the effect of the ageing of buildings. Results showed that the maximum increase in air leakage occurs during the first year after construction - approximately 25%, and then 3.7% in the second year, after which the increase rate becomes insignificant and relatively constant - approximately 0.3% per year. The findings from this study can provide significant information for building designs, building performance simulations and strengthening standards and guidelines policies on indoor environmental quality.

A novel method for the bronchial occlusion of prolonged air leakage using customized endobronchial plugs.

Background: The management of prolonged air leakage (PAL) is a significant clinical challenge, particularly for patients who are unfit for surgical treatment. The use of endoscopic interventions with occlusive devices has been reported previously; however, local availability and cost may represent potential hurdles, especially in developing countries. In this study, we presented a conical endobronchial plug of our design and evaluated the efficacy of making use of that in the treatment of PAL as a novel method. Methods: This retrospective study included a total of 23 patients with PAL who were not suitable for surgery and underwent bronchial occlusion using customized plugs. The responsible bronchi were identified by the balloon occlusion test or by end-tidal carbon dioxide detection. In each case, the plug was grasped at the knot of the tip with forceps and then inserted into the target bronchus with a flexible bronchoscope. Results: Of the 23 patients with intractable pneumothorax, 1 to 3 plugs (median =1) were successfully inserted into the affected bronchi of each patient for bronchial occlusion. Air leakage showed complete cessation in 13 patients (56.5%) and reduction in seven patients (30.4%). A total of 20 patients (87.0%) experienced successful removal of the drainage tube following plug occlusion or presented with additional pleurodesis. Complications included expectoration of the plug (n=1) and fever (n=1); no other severe complications were observed. Conclusions: Bronchial occlusion using customized endobronchial plugs appears to be an effective and simple option for the management of PAL in patients who are not suitable for surgery, especially in developing countries, as the customized plug is a cost-effective alternative.

Efficacy of oxidized regenerated cellulose combined with fibrin glue in reducing pulmonary air leakage after segmentectomy in a porcine lung model.

Objectives: Pulmonary air leakage is a common complication following lung resection. We have designed a new method combining oxidized regenerated cellulose and fibrin glue to cover the intersegmental plane in clinical lung segmentectomy to prevent postoperative air leakage. In this study, an excised porcine lung segmentectomy model was created to validate its adhesive strength and effect on reducing air leakage. Methods: In the pre-experiment, six different larger lung segments were separated using electrocautery on the fresh isolated porcine lungs (n = 5 in each group). The air leakage degree and operation time of the lung segments were comprehensively evaluated to select the most suitable target segment for establishing the ex vivo porcine lung segmentectomy models. In the experiment, according to the different materials covered on the intersegmental plane, these models were randomly divided into four groups: group A used fibrin glue and oxidized regenerated cellulose (ORC) mesh (n = 20); group B used fibrin glue and polyglycolic acid (PGA) sheet (n = 20); group C used fibrin glue (n = 20); group D was the blank control group (n = 20). The minimum air leakage pressure (MALP) of the selected target segment in each group was measured using a stepwise increase of airway pressure, and histological assessment was performed on the sealed area samples from the four groups. Results: The operation time of the a segment of the right cranial lobe (R1a) was shorter than that of other segments (p < 0.05), and there was no significant difference in the air leakage pressures between the six isolated segments (p = 0.76); thus, R1a was chosen for segmentectomy. In addition, the MALP was significantly higher in group A (41.8 ± 4.5 cmH2O) than in groups C (28.1 ± 2.3 cmH2O) and D (17.3 ± 1.2 cmH2O) (both p < 0.001). The MALP of group B (69.5 ± 5.2 cmH2O) was significantly higher than that of group A (p < 0.001), whereas that of group C was significantly higher than that of group D (p < 0.001). Histological examination confirmed that the combined use of fibrin glue and ORC or PGA patch adhered more firmly to the intersegmental plane than that of fibrin glue alone, although some gaps could be seen between the fibrin glue and the surface of the lung segments in group C. Conclusion: The application of ORC combined with fibrin glue on the intersegmental plane has a good sealing performance in the ex vivo porcine lung segmentectomy model, suggesting that ORC may be an effective alternative material to replace PGA sheet to combine with fibrin glue for preventing air leakage after segmentectomy.

Alaska pollock gelatin sealant shows long-term efficacy and safety in a pulmonary air leakage rat model.

OBJECTIVES: Postoperative prolonged air leakage is a frequent complication following lung resection. We have shown the high adhesive quality of a newly developed sealant based on a hydrophobically modified Alaska pollock-derived gelatin (ApGltn) sealant in acute in vivo settings. The purpose of this study was to investigate the long-term efficacy and safety of ApGltn sealant using rats as a preclinical model. METHODS: An air leakage rat model with a 5-mm pleural defect was created, to which ApGltn sealant or fibrin sealant was applied. In both groups, the rats were evaluated on days 1, 7, 14 and 28. In the ApGltn sealant group, days 56 and 84 were added to evaluate absorption as sealant was still present on day 28. The number of rats in each subgroup was 4 (for a total of 40). Lung specimens and blood samples were obtained for histological and haematological assessment. RESULTS: No findings suggesting infection or air leakage were observed. ApGltn sealant was absorbed from day 56 to day 84. Histologically, although neutrophil and lymphocyte infiltrations on the lung side did not differ between groups, those on the sealant side were significantly less in the ApGltn sealant group. Blood sample tests revealed no significant findings suggesting inflammation or organ damage in either group. CONCLUSIONS: ApGltn sealant showed long-term sealing efficacy and safety with mild inflammation in a pulmonary air leakage rat model. ApGltn sealant is expected to be a safe and effective sealant for clinical applications.

A combination of polyglycolic acid fabric and fibrin glue prevents air leakage from a lung defect.

OBJECTIVES: Air leakage after lung resection is a common morbidity that may lengthen hospital stay. Applying sealant to a lesion is an effective prophylaxis in clinical practice. This study aimed to examine the effect of a combination of a bioabsorbable polyglycolic acid (PGA) fabric and fibrin glue (FG) on air sealing by measuring the in vitro mechanical strength and degradation of the fabric, and in vivo histological changes after implantation. METHODS: A defect was created in the canine left upper lung lobe, and then filled with a fibrinogen solution and covered with a PGA sheet spray-coated with fibrinogen and thrombin. After 1 and 4 weeks, air leakage from the lesion was examined in vivo under airway pressure. Tissue samples were harvested for histological assessment. RESULTS: The mechanical strength of the PGA fabric remained at 80-90% of the baseline level for 1 week in phosphate-buffered saline, and then rapidly decreased to zero thereafter. Air leakage from the lung defect was prevented by the combination of PGA fabric and FG at 1 and 4 weeks. Histological examinations showed that PGA bundles persisted with a non-specific inflammatory response for 2 weeks and then gradually broke into sparse yarns surrounded by collagen fibres and capillaries by 8 weeks. The lung defect was filled with FG at 1 week and by granulation tissue thereafter. CONCLUSIONS: These results provide evidence for the efficacy of a combination of PGA fabric and FG for the prevention of air leakage in the critical period after lung surgery.