Changes in ventilatory mechanics and diaphragmatic function after lung volume reduction surgery in patients with COPD.

BACKGROUND: Lung volume reduction (LVR) has recently been used to treat severe emphysema. About 25% of the volume of each lung is removed with this method. Little is known about the mechanism of functional improvement so a study was undertaken to investigate the changes in ventilatory mechanics and diaphragmatic function in eight patients after LVR. METHODS: Measurements of work of breathing (WOB), intrinsic positive end expiratory pressure (PEEPi), dynamic compliance (Cdyn), and arterial carbon dioxide tension (PaCO2) were performed on the day before surgery and daily for seven days after surgery, as well as one, three, and six months after surgery. All measurements were performed on spontaneously breathing patients, simultaneously assessing oesophageal pressure via an oesophageal balloon catheter and air flow via a tightly adjusted mask. Diaphragmatic function was evaluated by measuring oesophageal and transdiaphragmatic pressure (Pdi) preoperatively and at one, three, and six months postoperatively. RESULTS: Mean forced expiratory volume in one second (FEV1) was 23 (3.6)% predicted, and all patients were oxygen dependent before the-operation. One day after LVR the mean decrease in WOB was 0.93 (95% confidence interval (CI) 0.46 to 1.40) joule/l, the mean decrease in PEEPi was 0.61 (95% CI 0.35 to 0.87) kPa, and the mean increase in Cdyn was 182.5 (95% CI 80.0 to 284.2) ml/kPa. Similar changes were found seven days and six months after surgery. PaCO2 was higher on the day after the operation but was significantly reduced six months later. Pdi was increased three and six months after surgery. CONCLUSIONS: Ventilatory mechanics improved immediately after LVR, probably by decompression of lung tissue and relief of thoracic distension. An improvement in diaphragmatic function three and six months postoperatively also contributes to improved respiratory function after LVR.

[1]  S. Nathan,et al.  Prediction of minimal pressure support during weaning from mechanical ventilation. , 1993, Chest.

[2]  F. Lemaire,et al.  Inspiratory work of breathing during spontaneous ventilation using demand valves and continuous flow systems. , 1988, The American review of respiratory disease.

[3]  O. Brantigan,et al.  Surgical treatment of pulmonary emphysema. , 1957, The American surgeon.

[4]  M. Tobin,et al.  PEEP, auto-PEEP, and waterfalls. , 1989, Chest.

[5]  O. Brantigan,et al.  A surgical approach to pulmonary emphysema. , 1959, The American review of respiratory disease.

[6]  N. D. Broussard,et al.  The Work of Breathing: Potential for Clinical Application and the Results of Studies Performed on 100 Normal Males , 1970, Annals of surgery.

[7]  J. Maurer,et al.  Pleural complications in lung transplant recipients. , 1995, The Journal of thoracic and cardiovascular surgery.

[8]  G. Simonneau,et al.  Diaphragm dysfunction induced by upper abdominal surgery. Role of postoperative pain. , 1983, The American review of respiratory disease.

[9]  T. Wanke,et al.  Dependence of maximal sniff generated mouth and transdiaphragmatic pressures on lung volume. , 1990, Thorax.

[10]  R. G. Fraser,et al.  Bronchial pressures and dimensions in health and obstructive airway disease , 1963 .

[11]  W A Zin,et al.  A simple method for assessing the validity of the esophageal balloon technique. , 2015, The American review of respiratory disease.

[12]  S. J. Cala,et al.  The effect of hyperinflation on respiratory muscle work in acute induced asthma. , 1990, The European respiratory journal.

[13]  J. Cooper,et al.  Bilateral pneumectomy (volume reduction) for chronic obstructive pulmonary disease. , 1995, The Journal of thoracic and cardiovascular surgery.

[14]  J. Marini,et al.  Impact of PEEP on lung mechanics and work of breathing in severe airflow obstruction , 1988 .

[15]  E. J. M. Campbell,et al.  THE RESPIRATORY MUSCLES , 1968 .

[16]  V. Ninane,et al.  Abdominal muscle use during breathing in patients with chronic airflow obstruction. , 1992, The American review of respiratory disease.

[17]  D. Leith,et al.  Dynamic hyperinflation and ventilator dependence in chronic obstructive pulmonary disease. , 2015, The American review of respiratory disease.

[18]  E. Briganti,et al.  Techniques and Results in Bilateral Sequential Single Lung TranspIantation , 1994 .

[19]  H. Schäfers,et al.  Pulmonary retransplantation for obliterative bronchiolitis. Intermediate-term results of a North American-European series. , 1994, The Journal of thoracic and cardiovascular surgery.

[20]  D. Bennett,et al.  The Bicore pulmonary monitor , 1993, Anaesthesia.

[21]  J. Milic-Emili,et al.  Continuous positive airway pressure reduces work of breathing and dyspnea during weaning from mechanical ventilation in severe chronic obstructive pulmonary disease. , 1990, The American review of respiratory disease.

[22]  O. Burghuber,et al.  Effect of lung transplantation on diaphragmatic function in patients with chronic obstructive pulmonary disease. , 1994, Thorax.

[23]  J. Cooper.  Technique to reduce air leaks after resection of emphysematous lung. , 1994, The Annals of thoracic surgery.

[24]  B. Fleury,et al.  Work of breathing in patients with chronic obstructive pulmonary disease in acute respiratory failure. , 2015, The American review of respiratory disease.

[25]  B. Ferris,et al.  The mechanical behavior of the lungs in healthy elderly persons. , 1957, The Journal of clinical investigation.

[26]  M. Tobin,et al.  Respiratory muscles in disease. , 1988, Clinics in chest medicine.

[27]  P. Rock,et al.  Thoracotomy increases peripheral airway tone and reactivity. , 1995, American Journal of Respiratory and Critical Care Medicine.