Subject(s)
Extracorporeal Membrane Oxygenation/methods , Lung Diseases/therapy , Lung Transplantation , Adult , Aged , Cystic Fibrosis/mortality , Cystic Fibrosis/therapy , Female , Follow-Up Studies , Humans , Hypertension, Pulmonary/therapy , Length of Stay , Lung Diseases/mortality , Lung Transplantation/mortality , Male , Middle Aged , Pulmonary Disease, Chronic Obstructive/mortality , Pulmonary Disease, Chronic Obstructive/therapy , Pulmonary Emphysema/mortality , Pulmonary Emphysema/therapy , Pulmonary Fibrosis/mortality , Pulmonary Fibrosis/therapy , Respiratory Function Tests , Retrospective Studies , Survival Analysis , Treatment OutcomeABSTRACT
Preoperative prediction of a successful outcome following lung volume reduction surgery (LVRS) for emphysema is imperfect. One mechanism could be improvement in respiratory muscle function yet controversy exists regarding the magnitude and mechanism of such an improvement. Therefore, we measured diaphragm strength in 18 patients before and after LVRS. Mean (S.D.) FRC fell from 6.53 to 5.40 l (p = 0.0001). Mean sniff transdiaphragmatic pressure increased from 76 to 87 cm H2O (14%, p < 0.03) and mean twitch transdiaphragmatic pressure (Tw Pdi) increased by 2.5 cm H2O at 3 months (12%, p = 0.03). There was a highly significant increase in twitch esophageal pressure (Tw Pes) (60%, p < 0.0001), which was maintained at 12 months (46% increase, p = 0.0004). No change was observed in quadriceps twitch tension in nine subjects in whom it was measured. After LVRS the ratio Tw Pes:Tw Pdi increased from 0.24 to 0.37 at 3 months (p = 0.0003) and 0.36 at 12 months (p = 008). Low values of Sn Pdi, Sn Pes, Tw Pes and a high RV/TLC ratio were the preoperative variables most predictive of improvement in shuttle walking distance. We conclude that LVRS improves diaphragm function primarily by alteration of lung volume. Patients with poor diaphragm function and high RV/TLC ratio preoperatively are most likely to benefit from the procedure.
Subject(s)
Diaphragm/physiopathology , Lung/surgery , Pulmonary Emphysema/surgery , Adult , Aged , Female , Follow-Up Studies , Forced Expiratory Volume/physiology , Humans , Male , Middle Aged , Muscle Contraction/physiology , Partial Pressure , Pulmonary Emphysema/physiopathology , Spirometry/methods , Statistics, Nonparametric , Time Factors , Total Lung Capacity/physiology , Vital Capacity/physiologyABSTRACT
Lung volume reduction surgery (LVRS) results in functional improvements in most patients. The mechanisms behind the improvements are not clear. We hypothesized that reduced inequalities in ventilation to perfusion ratio (V/Q) may be a contributing explanation. Nine patients who underwent LVRS were investigated by ventilation and perfusion scintigrams before and after surgery. In addition, 8 healthy subjects were investigated once. The relative ventilation, perfusion and V/Q were calculated in 1 x 1 cm lung elements. Normal range of the element count-rate was determined by the corresponding results in the normal subjects. Results of this small study show a significant effect of LVRS on V/Q, with reduction of shunt-like elements. We conclude that the functional improvement after LVRS to some extent may be explained by decreased V/Q inequality.
