Risk Factors for Prolonged Air Leak After Pulmonary Resection: A Systematic Review and Meta-analysis

Characterisation of pulmonary air leak measurements using a mechanical ventilator in a bench setup

Prolonged air leakage (AL) following pulmonary resections leads to prolonged hospital stay and post-operative complications. Intra- and postoperative quantification of AL might be useful for improving treatment decisions, but these measurements have not been characterised. AL calculations based on inspiratory and expiratory tidal volumes were investigated in an Intensive Care Unit mechanical ventilator circuit (Servo-I). AL was also measured by a digital chest drainage system. This study shows that AL measurements increase in accuracy when corrected for baseline deviations (R: 0.904 > 0.997, p < 0.001). Bland-Altman analysis revealed a funnel-shape, indicative of a detection threshhold. Corrected measurements were most accurate when averaged over five breaths and AL was >500 mL/min, with an estimated mean systemic bias of 7.4% (95%-limits of agreement [LoA]: 1.1%-13.7%) at 500 mL/min air leak. Breath-by-breath analysis showed most accurate results at AL >20 mL/breath (R: 0.989-0.991, p < 0.001) at tidal volumes between 350-600 mL. The digital drain had a mean systemic bias of -11.1% (95%-LoA: -18.9% to -3.3%) with homogenous scatter in Bland-Altman analysis and a strong correlation to the control measurement over a large range (0-2000mL/min, R: 0.999, p < 0.001). This study indicates that the Servo-I can be used for air leak quantification in clinically relevant ranges (>500 mL/min), but is unsuited for small leak detection due to a detection threshold. Researchers and clinicians should be aware of varying accuracy and interoperability characteristics between AL measurement devices.

Proof-of-principle of a lung sealant based on functionalized polyoxazolines: experiments in an ovine acute aerostasis model

OBJECTIVES

More effective lung sealants are needed to prevent prolonged pulmonary air leakage (AL). Polyoxazoline-impregnated gelatin patch (N-hydroxysuccinimide ester functionalized poly(2-oxazoline)s; NHS-POx) was promising for lung sealing ex vivo. The aim of this study is to confirm sealing effectiveness in an in vivo model of lung injury.

METHODS

An acute aerostasis model was used in healthy adult female sheep, involving bilateral thoracotomy, amputation lesions (bronchioles Ø > 1.5 mm), sealant application, digital chest tube for monitoring AL, spontaneous ventilation, obduction and bursting pressure measurement. Two experiments were performed: (i) 3 sheep with 2 lesions per lung (N = 4 NHS-POx double-layer, N = 4 NHS-POx single-layer, N = 4 untreated) and (ii) 3 with 1 lesion per lung (N = 3 NHS-POx single-layer, N = 3 untreated). In pooled linear regression, AL was analysed per lung (N = 7 NHS-POx, N = 5 untreated) and bursting pressure per lesion (N = 11 NHS-POx, N = 7 untreated).

RESULTS

Baseline AL was similar between groups (mean 1.38-1.47 l/min, P = 0.90). NHS-POx achieved sealing in 1 attempt in 8/11 (72.7%) and in 10/11 (90.9%) in >1 attempt. Application failures were only observed on triangular lesions requiring 3 folds around the lung. No influences of methodological variation between experiments was detected in linear regression (P > 0.9). AL over initial 3 h of drainage was significantly reduced for NHS-POx [median: 7 ml/min, length of interquartile range: 333 ml/min] versus untreated lesions (367 ml/min, length of interquartile range: 680 ml/min, P = 0.036). Bursting pressure was higher for NHS-POx (mean: 33, SD: 16 cmH2O) versus untreated lesions (mean: 19, SD: 15 cmH2O, P = 0.081).

CONCLUSIONS

NHS-POx was effective for reducing early AL, and a trend was seen for improvement of bursting strength of the covered defect. Results were affected by application characteristics and lesion geometry.

Autologous mesenchymal stromal cells embedded with Tissucol Duo® for prevention of air leak after anatomical lung resection: results of a prospective phase I/II clinical trial with long-term follow-up

BACKGROUND

Prolonged air leak (PAL) is the most frequent complication after pulmonary resection. Several measures have been described to prevent the occurrence of PAL in high-risk patients, however, the potential role of mesenchymal stem cells (MSCs) applied in the parenchymal suture line to prevent postoperative air leak in this setting has not been fully addressed.

OBJECTIVE

To analyse the feasibility, safety and potential clinical efficacy of the implantation of autologous MSCs embedded in Tissucol Duo® as a prophylactic alternative to prevent postoperative prolonged air leak after pulmonary resection in high-risk patients.

STUDY DESIGN

Phase I/II single-arm prospective clinical trial.

METHODS

Six patients with high risk of PAL undergoing elective pulmonary resection were included. Autologous bone marrow-derived MSCs were expanded at our Good Manufacturing Practice (GMP) Facility and implanted (embedded in a Tissucol Duo® carrier) in the parenchymal suture line during pulmonary resection surgery. Patients were monitored in the early postoperative period and evaluated for possible complications or adverse reactions. In addition, all patients were followed-up to 5 years for clinical outcomes.

RESULTS

The median age of patients included was 66 years (range: 55-70 years), and male/female ratio was 5/1. Autologous MSCs were expanded in five cases, in one case MSCs expansion was insufficient. There were no adverse effects related to cell implantation. Regarding efficacy, median air leak duration was 0 days (range: 0-2 days). The incidence of PAL was nil. Radiologically, only one patient presented pneumothorax in the chest X-ray at discharge. No adverse effects related to the procedure were recorded during the follow-up.

CONCLUSIONS

The use of autologous MSCs for prevention of PAL in patients with high risk of PAL is feasible, safe and potentially effective.

TRIAL REGISTRATION NO

EudraCT: 2013-000535-27.

CLINICALTRIALS

gov idenfier: NCT02045745.

Evaluating and developing sealants for the prevention of pulmonary air leakage: A systematic review of animal models

Sealants may provide a solution for pulmonary air leakage (PAL), but their clinical application is debatable. For sealant comparison, standardized animal models are lacking. This systematic review aims to assess methodology and quality of animal models for PAL and sealant evaluation. All animal models investigating lung sealing devices (e.g., staplers, glues, energy devices) to prevent or treat PAL were retrieved systematically from Embase, Pubmed and Web of science. Methodological study characteristics, risk of bias, reporting quality and publication bias were assessed. A total of 71 studies were included (N  =  75 experiments, N  =  1659 animals). Six different species and 18 strains were described; 92% of experiments used healthy animals, disease models were used in only six studies. Lesions to produce PAL were heterogenous, and only 11 studies used a previously reported technique, encompassing N  =  5 unique lesions. Clinically relevant outcomes were used in the minority of studies (imaging 16%, air leak 10.7%, air leak duration 4%). Reporting quality was poor, but revealed an upward trend per decade. Overall, high risk of bias was present, and only 18.7% used a negative control group. All but one study without control groups claimed positive outcomes (95.8%), in contrast to 84.3% using positive or negative control groups, which also concluded equivocal, adverse or inconclusive outcomes. In conclusion, animal studies evaluating sealants for prevention of PAL are heterogenous and of poor reporting quality. Using negative control groups, disease models and quantifiable outcomes seem important to increase validity and relevance. Further research is needed to reach consensus for model development and standardization.

Predictors of Long-Term Survival of Thoracoscopic Lobectomy for Stage IA Non-Small Cell Lung Cancer: A Large Retrospective Cohort Study

The standard of care for patients with early-stage non-small cell lung cancer (NSCLC) is anatomical lung resection with lymphadenectomy. This multicenter, retrospective, cohort study aimed to identify predictors of 5-year survival in patients after thoracoscopic lobectomy for stage IA NSCLC. The study included 1249 patients who underwent thoracoscopic lobectomy for stage IA NSCLC between 17 April 2007, and December 28, 2016. The 5-year survival rate equaled 77.7%. In the multivariate analysis, higher age (OR, 1.025, 95% CI: 1.002 to 1.048; p = 0.032), male sex (OR, 1.410, 95% CI: 1.109 to 1.793; p = 0.005), chronic obstructive pulmonary disease (OR, 1.346, 95% CI: 1.005 to 1.803; p = 0.046), prolonged postoperative air leak (OR, 2.060, 95% CI: 1.424 to 2.980; p < 0.001) and higher pathological stage (OR, 1.271, 95% CI: 1.048 to 1.541; p = 0.015) were related to the increased risk of death within 5 years after surgery. Lobe-specific mediastinal lymph node dissection (OR, 0.725, 95% CI: 0.548 to 0.959; p = 0.024) was related to the decreased risk of death within 5 years after surgery. These findings provide valuable insights for clinical practice and may contribute to improving the quality of treatment of early-stage NSCLC.

Repeated Pulmonary Metastasectomy: Third Operations and Beyond

BACKGROUND

For extrathoracic malignant neoplasms that have metastasized to the lungs, previous investigations have demonstrated both oncologic and survival benefits after pulmonary and repeated metastasectomy. Little is known about the feasibility of incrementally increasing numbers of subsequent metastasectomy procedures.

METHODS

We conducted a retrospective review of patients who underwent ≥3 pulmonary resection procedures for recurrent, metachronous metastatic disease of nonlung primary malignant neoplasms at a single institution between 1992 and 2020. Primary outcomes collected pertained to safety and feasibility, including estimated blood loss (EBL), hospital length of stay, and details of postoperative complications.

RESULTS

There were 117 patients who met inclusion criteria, having undergone at least 3 metastasectomy operations, with 55 (47.1%) undergoing a fourth operation and 20 (17.1%) undergoing a fifth operation. EBL did not differ between first and second operations (106.6 mL vs 102.5 mL; P = .76). It was, however, significantly greater at third operations (102.5 mL vs 238.7 mL; P = .000016). We noted an increase in wound complications between the second and third operations (0.9% vs 6.8%; P = .02) and incremental increases in likelihood of prolonged air leak with each subsequent operation. The need for reoperation was low for all and similar between operations. Importantly, hospital length of stay was similar for all procedures, as were the frequencies of hospital readmission.

CONCLUSIONS

Third-time redo pulmonary metastasectomy can be performed safely and feasibly in select patients. Further repeated resection should remain a therapeutic option for patients, although risks for potentially longer operating time, greater EBL, and prolonged air leaks may be anticipated.

Usefulness of free pericardial fat pads as pledgets for air leaks in pulmonary resection

PURPOSE

Intraoperative control of air leaks is important for preventing prolonged air leaks after surgery. The usefulness of suturing free pericardial fat pads (FPFPs) as pledgets for repairing air leaks was investigated.

METHODS

A total of 111 patients who underwent anatomical lung resection and required suture repair for intraoperative air leaks were retrospectively reviewed. Mattress sutures were performed using polyglycolic acid (PGA) sheets (PGA group; n = 60) in the early period (April 2014 to March 2018) and FPFPs (FPFP group; n = 51) in the late period (April 2018 to March 2021) as pledgets.

RESULTS

More patients had a history of smoking in the FPFP group than in the PGA group. The duration of air leakage was significantly shorter (mean 1.2 vs. 3.5 days, p = 0.002) and prolonged air leakage (> 5 days) was less frequently observed (23.3% vs. 5.9%, p = 0.016) in the FPFP group than in the PGA group. The FPFP group had fewer cases requiring pleurodesis and with recurrent air leaks than in the PGA group. In one case in the FPFP group, fat necrosis with fibrosis and fibrous adhesion to the visceral pleura was found on a pathological examination.

CONCLUSION

Parenchymal repair using FPFPs as pledgets can reduce prolonged air leaks after surgery.

Clinical and Economic Burden Associated with Prolonged Air Leaks Among Patients Undergoing Thoracic Resection: A Retrospective Database Analysis

Purpose

Prophylactic use of lung sealants among patients undergoing thoracic resection has been reported for the management of intraoperative air leaks and is associated with a lower incidence of prolonged air leak (PAL) and a shorter length of stay (LOS). This study estimated the incremental economic and clinical burden of PAL among patients with lung sealants used during thoracic resection in the United States.

Patients and Methods

This retrospective analysis examined hospital data (Premier Healthcare Database) for adults (age ≥18 years) with inpatient thoracic resection between October 2015 - March 2021 (first admission=index) and lung sealant used during their procedure. Follow-up extended through 90 days post-discharge. Patients were grouped by presence/absence of PAL (ie, diagnosis of post-procedural air leak or post-procedural pneumothorax with associated LOS exceeding 5 days). Outcomes included intensive care unit (ICU) days, total index hospital costs, all-cause 30-, 60-, and 90-day readmission, discharge status, and in-hospital mortality. Generalized linear models quantified associations between PAL and outcomes, accounting for hospital-level clustering, and patient, procedure, and hospital/provider characteristics.

Results

Among the 9727 patients included for study (51.0% female, 83.9% white, mean age 66 years), 12.5% had PAL, which was associated with significant incremental increases in ICU days (0.93 days, p<0.001) and total hospital cost ($11,119, p<0.001). PAL also decreased the likelihood of discharge to home (from 91.3% to 88.1%, p<0.001) and increased the risk of readmission within 30, 60, and 90 days by up to 34.0% (from 9.3% to 12.6%;11.7% to 15.4%;13.6% to 17.2%, respectively), all p<0.01. Absolute risk of mortality was low, but two times higher in patients with PAL versus those without PAL (2.4% vs 1.1%, p=0.001).

Conclusion

This analysis demonstrates that despite the prophylactic use of lung sealants, PAL continues to put a burden on the healthcare system, highlighting an unmet need for improved sealant technology.

Promising Effects of Digital Chest Tube Drainage System for Pulmonary Resection: A Systematic Review and Network Meta-Analysis

Objective: The chest tube drainage system (CTDS) of choice for the pleural cavity after pulmonary resection remains controversial. This systematic review and network meta-analysis (NMA) aimed to assess the length of hospital stay, chest tube placement duration, and prolonged air leak among different types of CTDS. Methods: This systemic review and NMA included 21 randomized controlled trials (3399 patients) in PubMed and Embase until 1 June 2021. We performed a frequentist random effect in our NMA, and a P-score was adopted to determine the best treatment. We assessed the clinical efficacy of different CTDSs (digital/suction/non-suction) using the length of hospital stay, chest tube placement duration, and presence of prolonged air leak. Results: Based on the NMA, digital CTDS was the most beneficial intervention for the length of hospital stay, being 1.4 days less than that of suction CTDS (mean difference (MD): −1.40; 95% confidence interval (CI): −2.20 to −0.60). Digital CTDS also had significantly reduced chest tube placement duration, being 0.68 days less than that of suction CTDSs (MD: −0.68; 95% CI: −1.32 to −0.04). Neither digital nor non-suction CTDS significantly reduced the risk of prolonged air leak. Conclusions: Digital CTDS is associated with better outcomes than suction and non-suction CTDS for patients undergoing pulmonary resections, specifically 0.68 days shorter chest tube duration and 1.4 days shorter hospital stay than suction CTDS.

Risk factors for prolonged air leak and need for intervention following lung resection

OBJECTIVES

Prolonged air leak (PAL; >5 days) following lung resection is associated with postoperative morbidity. We investigated factors associated with PAL and PAL requiring intervention.

METHODS

Retrospective review of all patients undergoing lobectomy, segmentectomy or wedge resection from 2016 to 2019 at our institution. Bronchoplastic reconstructions and lung-volume reduction surgeries were excluded. Incidence and risk factors for PAL and PAL requiring intervention were evaluated.

RESULTS

In total, 2384 patients were included. PAL incidence was 5.4% (129/2384); 22.5% (29/129) required intervention. PAL patients were more commonly male (56.6% vs 39.7%), older (mean age 69 vs 65 years) and underwent lobectomy or thoracotomy (all P < 0.001). Patients with PAL had longer length of stay (9 vs 3 days), more discharge needs and increased odds of complication (all P < 0.050).Twenty-nine patients required intervention (9 chest tubes; 4 percutaneous drains; 16 operations). In 50% of operative interventions, an air leak source was identified; however, the median time from intervention to resolution was 13 days. Patients requiring intervention had increased steroid use, lower diffusion capacity for carbon monoxide and twice the length of stay versus PAL patients (all P < 0.050).On univariable analysis, forced expiratory volume in 1 s (FEV1) <40%, diffusion capacity for carbon monoxide <50%, steroid use and albumin <3 had increased odds of intervention (P < 0.050).

CONCLUSIONS

Age, gender and operative technique were related to PAL development. Patients with worse forced expiratory volume in 1 s or diffusion capacity for carbon monoxide, steroid use or poor nutrition were less likely to heal on their own, indicating a population that could benefit from earlier intervention.

Suction Versus Nonsuction Drainage After Uniportal Video-Assisted Thoracoscopic Surgery: A Propensity Score-Matched Study

Background

Uniportal video-assisted thoracoscopic surgery (UniVATS) was utilized with a rapid growth. The evidence is sparse, however, on whether to add external suction to water-seal drainage for chest drainage after UniVATS. This retrospective propensity score-matched study aimed to identify the necessity of adding external suction to chest drainage after UniVATS.

Methods

Patients with lung cancer who underwent UniVATS were included from our prospectively maintained database. Patients were divided into two cohorts based on the addition of external suction to postoperative water-seal drainage or not. Propensity score-matched analysis was performed to identify the impact of suction on chest tube duration, incidence of persistent air leak, hospital stay, and hospitalization cost. Multivariable model with interaction terms was constructed to identify impact of covariables on effect of suction.

Results

The two cohorts matched well on baseline characteristics (nonsuction: 173; suction: 96). Compared with nonsuction group, suction group showed longer median chest tube duration (3 vs. 2 days, p = 0.003), higher incidences of persistent air leak (9.4% vs. 1.2%, p = 0.003), persistent drainage (16.8% vs. 5.8%, p = 0.007), and reduced drainage volume within first 3 postoperative days (386.90 vs. 504.78 ml, p = 0.011). Resection extent was identified to mediate the relationship between suction and chest tube drainage.

Conclusions

These findings discouraged adding external suction to water-seal drainage after UniVATS regarding longer chest tube duration and more persistent air leak. Patients undergoing lobectomy would benefit more from water-seal drainage without external suction compared with those doing sublobectomy.

Predictive factors and economic impact of prolonged air leak after pulmonary resection

OBJECTIVE

Prolonged air leak (PAL) is one of the most common complications after pulmonary resection for lung cancer. This study aimed to identify the factors that predict PAL, and to evaluate the impact of PAL on the development of additional complications and cost of hospitalization.

METHODS

A total of 2278 patients who underwent pulmonary resection other than pneumonectomy for lung cancer from 2014 to 2018 were retrospectively enrolled in this study. PAL was defined as air leak that continued more than 5 days after the operation. Multivariate analyses were conducted to identify significant predictors of PAL, using clinical information. Development of complications other than PAL, and cost of hospitalization care were also analyzed.

RESULTS

PAL was observed in 91 (4.0%) cases. Multivariate logistic regression analysis revealed that the presence of intrathoracic adhesion (odds ratio [OR] 4.476, p < 0.001), smoking history > 20 pack-year (OR 2.441, p = 0.005), male sex (OR 2.269, p = 0.013), and lobectomy or bilobectomy (OR 1.935, p = 0.025) were significant risk factors for PAL. The presence of PAL was related to the development of additional complications (p < 0.001). The cost of hospitalization care in patients with PAL was about 1.3 times higher than that in patients without PAL (p < 0.001).

CONCLUSIONS

PAL is related to additional complications and higher cost of hospitalization care. Surgeons should pay careful attention to minimize the incidence of PAL in patients with risk factors including intrathoracic adhesion, history of heavy smoking, male sex, and lobectomy or bilobectomy.

The Correlation Between Fissureless Technique and Prolonged Air Leak for Patients Undergoing Video-Assisted Right Upper Lobectomy

PURPOSE

We aimed to assess the clinical usefulness of the fissureless technique, which avoided dissection of the lung parenchyma over the pulmonary artery, in preventing prolonged air leak after video-assisted thoracic surgery right upper lobectomy (VATS RUL).

METHODS

Perioperative outcomes, including the frequency of prolonged air leak after fissureless technique or traditional fissure dissection technique, which dissected the lung parenchyma through the fissure, were compared in patients who underwent VATS RUL (n = 213) between January 2016 and March 2020. We adopted our fissural grade to evaluate the degree of fused fissure ranging from II (light incomplete fissure) to IV (severe incomplete fissure), which covered all fissural grades in 213 patients.

RESULTS

Fifty-four and 159 patients underwent fissureless and traditional techniques, respectively. Significant differences in the incidence of prolonged air leak (p = 0.037), time to air leak cessation (p = 0.047), and duration of chest tube placement (p = 0.017) were observed between fissureless and traditional technique groups. On multivariable analysis, traditional technique (p = 0.005), and greater fissural grade (III vs II, p = 0.020; IV vs II, p = 0.001) were significantly associated with prolonged air leak.

CONCLUSIONS

Fissureless technique during VATS RUL can be a superior alternative to the traditional technique to prevent prolonged air leak in treating incomplete fissures.

The Year in Thoracic Anesthesia: Selected Highlights from 2019

THIS special article is the 4th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan; the associate editor-in-chief, Dr. Augoustides; and the editorial board for the opportunity to expand this series, the research highlights of the year that specifically pertain to the specialty of thoracic anesthesia. The major themes selected for 2019 are outlined in this introduction, and each highlight is reviewed in detail in the main body of the article. The literature highlights in this specialty for 2019 include updates in the preoperative assessment and optimization of patients undergoing lung resection and esophagectomy, updates in one lung ventilation (OLV) and protective ventilation during OLV, a review of recent meta-analyses comparing truncal blocks with paravertebral catheters and the introduction of a new truncal block, meta-analyses comparing nonintubated video-assisted thoracoscopic surgery (VATS) with those performed using endotracheal intubation, a review of the Society of Thoracic Surgeons (STS) recent composite score rating for pulmonary resection of lung cancer, and an update of the Enhanced Recovery After Surgery (ERAS) guidelines for both lung and esophageal surgery.