Objective To compare negative expiratory pressure (NEP)technique with conventional test in detecting expiratory flow limitation (EFL)in chronic obstructive pulmonary diseases( COPD) patients. Methods EFL was measured with NEP technique and conventional method respectively in 72 COPD patients;EFL was measured with NEP technique in 20 COPD patients who failed to perform conventional test. Results EFL was detected in 54 of the 72 COPD patients. NEP test was successfully performed on the 20 patients, and 19 of them were found with EFL. The level of forced expired volume in one second percentage( FEV_1 % ) of the patients with 2-score group (46. 92 ± 12. 74) % and 3-score group (33. 35 ± 8.96)% were significantly lower than that of the 1-score group(63. 60 ±16.65)%. Area under curve of NEP technique and conventional test in ROC is 0. 903 and 0. 761 respectively. Conclusions As compared with conventional test, EFL detected with NEP technique is more reliable in evaluating dyspnea of COPD patients. It is simple and doesn't require any cooperation of the patients. NEP technique can be applied in COPD patients who fail to receive conventional test.

BACKGROUND: Stellate ganglion block (SGB) has become a technique frequently used in the field of pain management for its wide indication spectrum. Its ameliorative effect on cephal-facial pain may be achieved by regulating the cerebrovascular diastolic and systolic functions and intensifying cerebral perfusion.OBJECTIVE: To observe the influence of SGB on the blood velocity of anterior cerebral artery (ACA), middle cerebral artery (MCA), posterior cerebral artery (PCA) and vertebral artery with three-dimensional transcranial Doppler (TCD) in patients with caphal-facial diseases caused by is chemia or vascular spasm.DESIGN: A before-after control observation.SETTINGS: Department of Pain Management, Guizhou Provincial Orthopaedic Hospital; Department of Anesthesiology, the First Affiliated Hospital of Guangzhou Medical College; Department of Anesthesiology, the Second Affiliated Hospital of Sun Yat-sen University.PARTICIPANTS: Twenty patients of 18-50 years old were selected from the Department of Pain Management of Guizhou Provincial Orthopaedic Hospital from March 2004 to December 2005, including 6 cases of migraine,3 of cluster headache, 4 of muscle tension-type headache, 2 of nervous tinnitus and earache, and 5 of derangement of temporomandibular joint.METHODS: Unilateral SGB was performed by means of paratracheal anterior technique, with the following compound prescription: lidocaine (20 g/L)2.5 mL and dexamethasone 1 mg in normal saline with a total volume of 10 mL. SGB was performed once a day for 7 consecutive days as one course.MAIN OUTCOME MEASURES: The changes of blood velocity of ACA,MCA, PCA and vertebral artery were observed with three-dimensional TCD before SGB and at 30 minutes after SGB.RESULTS: All the 20 patients finished the treatment and entered the analysis of results. After treatment, the blood velocities of ACA, MCA and PCA of the blocked side were increased remarkably as compared with those before treatment [(76.20±3.83), (61.95±2.50) cm/s; (83.65±2.36),(77.55±2.69) em/s; (65.20±2.99), (58.70±2.2.35) cm/s; P ＜ 0.01], but that of vertebral artery had no significant change before and after treatment [(47.20±2.04), (45.55±2.23) cm/s, P ＞ 0.05]. CONCLUSION: The blood velocities of the blocked side are obviously increased after treatmeut, the increased blood velocities of ACA, MCA and PCA have important clinical significance for the blood supply of cerebral hemisphere, especially the anterior 2/3 part, but had little great influence on vertebral artery, indicating that SGB has great pertinence to the caphalfacial diseases caused by ischemia or vascular spasm, and can ameliorate the cerebral blood perfusion.