RESUMO
BACKGROUND: Medicine treatment of chronic respiratory failure achieved little effect. Interfering chronic respiratory failure of chronic cor pulmonale with noninvasive positive pressure ventilation (NIPPV) may be an effective measure to eliminate symptom and physical sign of patients.OBJECTIVE: To investigate the effect of nocturnal noninvasive positive pressure ventilation (NIPPV) on respiratory muscle function, pulmonary function of chronic respiratory failure patients with stable chronic cor pulmonale at high altitude area (HACCP).DESIGN: A completely randomized grouping design and randomized control trial.SETTING: Center of Respiratory Medicine, the 4th Hospital of Lanzhou Military Area Command of Chinese PLA.PARTICIPANTS: Totally 60 HACCP patients with chronic respiratory failure in stable stage, 38 male and 22 female, were admitted to Department of Respiratory Disease, the 4th hospital of Chinese PLA from October 2002 to November 2004. All cases, after informed consent was obtained,were randomly divided into two groups, including treatment group and control group with 30 cases in each group.METHODS: [1] Treatment group: Fitted with ventilator with pressure support ventilation (PSV) mode or positive end-expiratory pressure (PEEP)mode from 22:00 to next 7:00 every night. Before and after 5 weeks therapeutics, pulmonary function, arterial blood gas, respiratory muscle function and 6-minute walking distance (6MWD) were measured. Control group:Those were either assessed in inpatient objects stabled at least 1 week as control group before discharged and 5 weeks thereafter. [2] 6-minute walking distance (6MWD) test: Patients made their effects to walk 6 minutes in20 meters long corridor, or could not go on because of dyspnea, walking distance was determined. Using electronic diaphragmatic function meter,oral maximal inspiratory pressure (PImax) and maximal expiratory pressure(PEmax) were determined, then maximal transdiaphragmatic pressure (Pdimax) was measured with airway block method. With blood gas analyzer,partial pressure of oxygen in arterial blood (PaO2) and partial pressure of carbon dioxide in arterial blood (PaCO2) were assessed. With electronic spirometre, forced expiratory volume in one second (FEV1) expressed as percentage predicted (FEV1%), FEV1 forced vital capacity (FVC) ratio(FEV1/FVC) were assessed. [3] Differences between the groups in response to rehabilitation were identified using the unpaired Student's t test, while changes within groups were measured using the paired Student's t test.MAIN OUTCOME MEASURES: Respiratory muscular function, pulmonary function, arterial blood gas and 6-minute walking distance in two groups before and after intervention.RESULTS: All 60 chronic respiratory failure patients with stable chronic cor pulmonale were involved in-the analysis of results. Every parameters of blood gas and pulmonale function in two groups were similar before intervention (P ＞ 0.05). After 5-week intervention, PaO2, FEV1%, FEV1/FVC,PImax, PEmax, Pdimax and 6MWD were higher than before in treatment group and those in control group (P ＜ 0.05-0.01). PaCO2 after therapy was lower than before in treatment group and that in control group after treatment (P ＜ 0.01).CONCLUSION: Nocturnal NIPPV can markedly improve the arterial blood gas and pulmonary function, and increase respiratory muscle strength.