Airway mucus and epithelial function in a canine model of single lung autotransplantation

Early rehabilitation after lung transplantation with extracorporeal membrane oxygenation (ECMO) of COVID-19 patient: a case report

Even when severe acute respiratory syndrome coronavirus 2-related coronavirus disease 2019 (COVID-19) is treated with first-line drugs, it progresses and leads to irreversible loss of lung function in some critically ill patients, and lung transplantation is an effective treatment for end-stage chronic pulmonary disease. This case report mainly describes the rehabilitation of a 66-year-old female patient with severe COVID-19 after bilateral lung transplantation. The old patient had a body mass index of 31.2 kg/m². She underwent bilateral lung transplantation due to severe and irreversible injury of both lungs. Long-term mechanical ventilation and extracorporeal membrane oxygenation (ECMO) treatment and preoperative and postoperative high-dose corticosteroid therapy and due to the size of the donor lung does not match the size of the recipient’s diseased lung, and the right middle lobe of the graft is removed before transplantation. Weaning from the ventilator failed due to weak neuromuscular drive, and muscle strength. A full, personalized pulmonary rehabilitation program was initiated with the help of the physical therapists, the respiratory therapy, the doctors, the nurses and psychotherapist team based on the functional levels. The rehabilitation intervention was conducted on postoperative day 4, This included posture management, airway clearance techniques, respiratory training, muscle strength training, transfer training, daily therapeutic bronchoscopy and psychological support. The ECMO was removed successfully on the fifth day. the patient’s physical function, muscle strength and the quality of life has been improved. The good prognosis after rehabilitation indicates that early rehabilitation intervention is effective and feasible and safety for patients after lung transplantation.

Management Strategies for Complex Bronchopleural Fistula

The management of complex bronchopleural fistula remains a major therapeutic challenge for the thoracic surgeon. Although the incidence of bronchopleural fistula following lung resection has decreased in recent years to 1% to 2%, when it occurs, it is associated with significant morbidity and mortality. Using illustrative cases, the epidemiology and pathophysiology of bronchopleural fistula are reviewed and operative strategies are discussed. Algorithms for the diagnosis and treatment are suggested on the basis of cases described in the literature. The best way to prevent a fistula is to rigorously follow the surgical techniques described, with minimal devascularization of the bronchus and prophylactic coverage of the stump in high-risk patients. Successful management of a fistula is combined with treatment of the associated empyema cavity. Definitive repair should be accomplished expeditiously, minimizing the number of procedures performed. When treatment is protracted, secondary complications are more likely and survival is adversely affected. The first step should be control of active infection and adequate drainage of the hemithorax, followed by timely repair of the bronchopleural fistula when possible and reinforcement of the stump with vascularized tissue. If a residual cavity is present it must also be obliterated with a pedicled muscle flap.

The effects on mucociliary clearance of prednisone associated with bronchial section

OBJECTIVE

Infections have been and remain the major cause of morbidity and mortality after lung transplantation. Because mucociliary clearance plays an important role in human defense mechanisms, the influence of drugs on the mucociliary epithelium of patients undergoing lung transplantation must be examined. Prednisone is the most important corticosteroid used after lung transplantation. The aim of this study was to evaluate the effects of bronchial transection and prednisone therapy on mucociliary clearance.

METHODS

A total of 120 rats were assigned to 4 groups according to surgical procedure or drug therapy: prednisone therapy (1.25 mg/kg/day); bronchial section and anastomosis + prednisone therapy (1.25 mg/kg/day); bronchial section + saline solution (2 ml/day); and saline solution (2 ml/day). After 7, 15, or 30 days, the animals were sacrificed, and the lungs were removed from the thoracic cavity. The in situ mucociliary transport velocity, ciliary beat frequency and in vitro mucus transportability were evaluated.

RESULTS

Animals undergoing bronchial section surgery and anastomosis had a significant decrease in the ciliary beat frequency and mucociliary transport velocity 7 and 15 days after surgery (p<0.001). These parameters were normalized 30 days after the surgical procedure. Prednisone improved mucous transportability in the animals undergoing bronchial section and anastomosis at 15 and 30 days (p<0.05).

CONCLUSION

Bronchial section and anastomosis decrease mucociliary clearance in the early postoperative period. Prednisone therapy improves mucus transportability in animals undergoing bronchial section and anastomosis.

J. Maxwell Chamberlain Memorial Paper. Early fundoplication prevents chronic allograft dysfunction in patients with gastroesophageal reflux disease

BACKGROUND

Chronic allograft dysfunction limits the long-term success of lung transplantation. Increasing evidence suggests nonimmune mediated injury such as due to reflux contributes to the development of bronchiolitis obliterans syndrome. We have previously demonstrated that fundoplication can reverse bronchiolitis obliterans syndrome in some lung transplant recipients with reflux. We hypothesized that treatment of reflux with early fundoplication would prevent bronchiolitis obliterans syndrome and improve survival.

METHODS

A retrospective analysis of 457 patients who underwent lung transplantation from April 1992 through July 2003 was conducted. Patients were stratified into four groups: no history of reflux, history of reflux, history of reflux and early (< 90 days) fundoplication and history of reflux and late fundoplication.

RESULTS

Incidence of postoperative reflux was 76% (127 of 167 patients) in pH confirmed subgroups. In 14 patients with early fundoplication, actuarial survival was 100% at 1 and 3 years when compared with those with reflux and no intervention (92% +/- 3.3, 76% +/- 5.8; p < 0.02). Further, those who underwent early fundoplication had improved freedom from bronchiolitis obliterans syndrome at 1 and 3 years (100%, 100%) when compared with no fundoplication in patients with reflux (96% +/- 2.5, 60% +/- 7.5; p < 0.01).

CONCLUSIONS

Reflux is a frequent medical complication after lung transplantation. Although the number of patients undergoing early fundoplication is small, our results suggest early aggressive surgical treatment of reflux results in improved rates of bronchiolitis obliterans syndrome and survival. Further research into the mechanisms and treatment of nonalloimmune mediated lung allograft injury is needed to reduce rates of chronic lung failure.

Improved lung allograft function after fundoplication in patients with gastroesophageal reflux disease undergoing lung transplantation

OBJECTIVES

Bronchiolitis obliterans is the greatest limitation to the long-term applicability of lung transplantation. Although alloimmune events are important, nonimmune events, such as gastroesophageal reflux, might contribute to lung injury and the development of bronchiolitis obliterans syndrome.

METHODS

We retrospectively studied the 396 patients who underwent lung transplantation at the Duke Lung Transplant Program from April 1992 to April 2002. Reflux was assessed for using an ambulatory 24-hour esophageal pH probe.

RESULTS

Reflux assessment with an esophageal pH probe was obtained in 128 patients after lung transplantation. Abnormal pH study results were present in 93 (73%) patients. Forty-three patients underwent a surgical fundoplication. There was no in-hospital or 30-day mortality in the patients undergoing fundoplication. At the time of fundoplication, 26 patients met the criteria for bronchiolitis obliterans syndrome. After fundoplication, 16 patients had improved bronchiolitis obliterans syndrome scores, with 13 of these patients no longer meeting the criteria for bronchiolitis obliterans syndrome. In patients at least 6 months after lung transplantation and 6 months after fundoplication, the forced expiratory volume in 1 second improved by an average of 24% (mean forced expiratory volume in 1 second before fundoplication, 1.87 L; mean forced expiratory volume in 1 second after fundoplication, 2.19 L/sec; P <.0002). Overall actuarial survival was significantly better in patients who had either normal pH studies or who had fundoplication.

CONCLUSIONS

Gastroesophageal reflux disease is very common after lung transplantation and appears to contribute to mortality and development of bronchiolitis obliterans syndrome. Fundoplication in lung transplant recipients with gastroesophageal reflux disease is associated with significant improvements in lung function, particularly if performed before the late stages of bronchiolitis obliterans syndrome.

Effects of Bronchial Transection and Reanastomosis on Mucociliary System

STUDY OBJECTIVES

The mechanisms involved in the impairment of mucociliary function after lung transplantation are not completely understood. The purpose of the present study was to isolate the effects of unilateral bronchial transection and reanastomosis in a rat model.

DESIGN

In situ bronchial mucociliary transport (MCT) was determined proximal and distal to the bronchial anastomosis, as well as in the right bronchus, in 48 rats classified into six groups: intact rats, and rats at 1 day, 2 days, 7 days, 15 days, and 30 days after bronchial transection and reanastomosis of the left main stem bronchus. In vitro mucus transportability and mucus contact angle were studied in another group of eight rats after 1 week of surgery.

RESULTS

Distal to the anastomosis site, left bronchus in situ MCT (mean +/- SD) was 0.26 +/- 0.19 mm/min for the intact group, and 0.11 +/- 0.13 mm/min, 0.07 +/- 0.04 mm/min, 0.03 +/- 0.04 mm/min, 0.07 +/- 0.12 mm/min, and 0.05 +/- 0.06 mm/min for 1 day, 2 days, 7 days, 15 days, and 30 days after surgery, respectively (all significantly reduced, p < 0.05). No intergroup differences were found proximal to the anastomosis (p = 0.30). When comparing the left and right bronchi, differences were detected in both distal (p < 0.0001) and proximal sides (p = 0.0001). No significant differences in mucus transportability in vitro were found (p = 0.15). Mucus contact angle of the left bronchus (52.8 +/- 20.5 degrees ) was significantly greater than that of the mucus from the right bronchus (34.4 +/- 12.9 degrees; p < 0.05).

CONCLUSIONS

We conclude that bronchial transection and reanastomosis lead to a marked impairment of MCT in distal airways, which can in part be explained by alterations in the surface properties of mucus.

YM-40461, a potent surfactant secretagogue, improves mucociliary clearance in SO2-exposed guinea pigs

The effects of the new pulmonary surfactant secretagogue YM-40461, 1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl) urea, on tracheal mucociliary transport (MCT) were assessed using guinea pigs with acute bronchitis. Acute bronchitis was induced by SO2 gas exposure (400 ppm for 3 h). MCT velocity was measured by means of the dye gelatin technique. YM-40461 at doses of 1-10 mg/kg, p.o. induced recovery of MCT function, with an ED50 value of 2.4 mg/kg. Maximal recovery (78.0+/-12.5%) was observed 2 h in the animals treated with 10 mg/kg of YM-40461. Ambroxol and bromhexine showed less effect on the MCT dysfunction than YM-40461. An artificial surfactant (Surfacten) also aided recovery. YM-40461 at a dose of 10 mg/kg, p.o. significantly improved surfactant production without affecting mucus secretion. These results show that YM-40461 ameliorates MCT dysfunction caused by SO2 exposure by activation of pulmonary surfactant secretion.

A comparison of a new mucolytic N-acetylcysteine L-lysinate with N-acetylcysteine: airway epithelial function and mucus changes in dog

A newly synthesized mucolytic agent, N-acetylcysteine L-lysinate (Nacystelyn) was studied. Tracheal mucus velocity (TMV), transepithelial potential difference (PD), rheological properties, and ion content of collected airway secretions were evaluated in six healthy mongrel dogs after placebo, Nacystelyn (NAL) and acetylcysteine (NAC) metered dose inhaler (MDI) aerosols. Although TMV was increased and viscoelasticity decreased after both treatments, the treatment effect with NAL was significantly greater. Furthermore, NAL increased the negative PD and CI- content of secretions in the trachea, an effect not observed after NAC. Both compounds increased ciliary beat frequency (CBF) on the frog palate at a concentration range similar to that approximated in dog airways. The increased mucociliary clearance could be partially explained by favourable rheological changes combined with stimulation of CBF. Since both compounds break disulfide bonds in mucus polymers, the greater change in mucus rheology and clearance rate after NAL, without change in water content, could be explained by the increase in CI- content. Nacystelyn appears to combine different modes of action which synergistically cause an increase in the clearance rate of airway secretions.