Assuntos
Oxigenação por Membrana Extracorpórea/métodos , Pneumopatias/terapia , Transplante de Pulmão , Adulto , Idoso , Fibrose Cística/mortalidade , Fibrose Cística/terapia , Feminino , Seguimentos , Humanos , Hipertensão Pulmonar/terapia , Tempo de Internação , Pneumopatias/mortalidade , Transplante de Pulmão/mortalidade , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/mortalidade , Doença Pulmonar Obstrutiva Crônica/terapia , Enfisema Pulmonar/mortalidade , Enfisema Pulmonar/terapia , Fibrose Pulmonar/mortalidade , Fibrose Pulmonar/terapia , Testes de Função Respiratória , Estudos Retrospectivos , Análise de Sobrevida , Resultado do TratamentoRESUMO
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.
Assuntos
Diafragma/fisiopatologia , Pulmão/cirurgia , Enfisema Pulmonar/cirurgia , Adulto , Idoso , Feminino , Seguimentos , Volume Expiratório Forçado/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Contração Muscular/fisiologia , Pressão Parcial , Enfisema Pulmonar/fisiopatologia , Espirometria/métodos , Estatísticas não Paramétricas , Fatores de Tempo , Capacidade Pulmonar Total/fisiologia , Capacidade Vital/fisiologiaRESUMO
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.