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Biomedical subjects

Rong-chang Chen

Publications and source records attributed to Rong-chang Chen.

14 recordsLinked to original sources
PubMed2006

[The relationship between mouth pressure or tracheal pressure and esophagus pressure and diaphragmatic pressure].

OBJECTIVE: To investigate the relationship between mouth pressure (Pmo) or tracheal pressure (Ptr) and esophagus pressure (Pes) or transdiaphragmatic pressure. METHODS: Seventeen patients were involved in the study. Maximal inspiratory pressure (MIP), maximal transdiaphragmatic pressure (Pdi(max)), maximal esophagus pressure (Pes(max)), twitch mouth pressure (TwPmo), twitch transdiaphragmatic pressure (TwPdi) and twitch esophagus pressure (TwPes) were measured before narcotization as a normal procedure for the abdominal operation and twitch tracheal pressure (TwPtr(nar)), twitch esophagus pressure (TwPes(nar)) and twitch transdiaphragmatic pressure (TwPdi(nar)) were dynamically monitored during narcotization. RESULTS: (1) The correlation coefficient (r) values between Pdi(max) and MIP, TwPdi and TwPmo, TwPdi(nar) and TwPtr(nar), Pes(max) and MIP, TwPes and TwPmo, TwPes(nar) and TwPtr(nar) were 0.976 +/- 0.030, 0.816 +/- 0.155, 0.923 +/- 0.446, 0.981 +/- 0.185, 0.829 +/- 0.168 and 0.955 +/- 0.292, respectively. (2) The coefficient variation (CV) of MIP, Pes(max), Pdi(max), TwPmo, TwPes and TwPdi were (14.2 +/- 4.7)%, (15.2 +/- 4.3)%, (15.5 +/- 4.1)%, (30.4 +/- 15.9)%, (10.8 +/- 5.1)% and (9.9 +/- 4.0)%, respectively. The CV of TwPmo was the highest (compare with others, all P < 0.05) and that of TwPes and TwPdi was the lowest (compare with others, all P < 0.05). There was no significant difference among MIP, Pes(max) and Pdi(max) (P > 0.05). (3) The r value between the changing values of TwPtr(nar) and TwPdi(nar) or TwPes(nar) during narcotization were 0.839 or 0.894 (P = 0.000, respectively). CONCLUSION: The measurement of MIP and TwPmo should be repeated and the highest value should be chosen in order to reduce the possibility of underestimating the function of diaphragm, which could be dynamically monitored by TwPtr(nar).

Abdomen↗
PubMed2006

[Investigation of proximal femoral marrow with magnetic resonance imaging in recovered patients with severe acute respiratory syndrome].

OBJECTIVE: To determine the effect of corticosteroid treatment and severe acute respiratory syndrome (SARS) infection itself on the marrow conversion in the proximal femoral marrow in the recovered patients of health care workers with SARS. METHODS: The distribution of proximal femoral marrow on MR imaging of 148 health care workers with recovered SARS including 106 cases treated with varied dosage of steroids and 42 cases without steroid, and 97 age and sex matched health adults as controls were observed. The index of marrow conversion (signal intensity of the femoral neck and intertrochanteric area divided by signal intensity of the greater trochanter multiplied by 100%) was quantitatively measured and compared between SARS patients treated with steroid and without steroid and the normal control group. RESULTS: In 106 cases treated with steroid of the 148 health care workers, femoral head osteonecrosis was found in 4 cases, bilateral femoral marrow edema in 2 cases, femoral marrow infarction in 1 case. The index of marrow conversion in the normal controls, in SARS patients treated without and with steroids was (79.4 +/- 6.8)%, (86.9 +/- 7.4)%, (88.6 +/- 5.9)%, respectively. There was significantly statistical difference between groups (P < 0.05). CONCLUSION: In addition to fat conversion in the proximal femoral marrow due to steroid treatment, the infection of SARS itself may promote an excessively conversion of the red marrow to yellow marrow of the femoral neck in SARS patients.

Adolescent↗
PubMed2006

[Expiratory flow limitation detected by negative expiratory pressure in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To evaluate the relationship between expiratory flow limitation (EFL) and chronic dyspnea and the effect of bronchodilator on EFL in patients with chronic obstructive pulmonary disease (COPD). METHODS: Thirty-three ambulatory patients with COPD (46 - 78 yrs; male 31, female 2) were included in this study. The severity of chronic dyspnea was rated according to the dyspnea scale proposed by the Medical Research Council (MRC). EFL was measured by applying negative pressure at the mouth during tidal expiration before and after bronchodilation test (inhalation of 400 microg salbutamol). RESULTS: EFL was detected in 12 (36%) of the 33 COPD patients in both seated and supine positions and in 11 (33%) only in supine position. There was a significant difference in the percent predicted forced expired volume in one second (FEV(1%)pred) between subgroups of the patients with or without EFL (t = 7.601, P < 0.01). The mean values of FEV(1%)pred in non-EFL group and EFL group was (66 +/- 16)% and (31 +/- 10)%, respectively, and the value was lowest in patients who showed EFL both in seated and supine positions [(24 +/- 7)%]. Both three-point EFL and five-point EFL were significantly correlated with FEV(1) (r = -0.836 and -0.818, respectively, all P < 0.01). There was a significant correlation between MRC dyspnea scale and three-point EFL and five-point EFL (r = 0.903 and 0.912, respectively, all P < 0.01). In the multiple regression analysis, five-point EFL was a better predictor of dyspnea than FEV(1) (regression coefficient was 0.679 and -0.265, respectively, P < 0.01 and 0.029, respectively). EFL persisted after salbutamol in all of the 23 patients with EFL under baseline conditions. CONCLUSIONS: EFL as measured by negative expiratory pressure (NEP) technique may be more useful in the evaluation of dyspnea in COPD patients than routine lung function measurements. The EFL in COPD patients is irreversible after bronchodilator administration.

Aged↗
PubMed2006

[Retrospective discriminant analysis of the clinical diagnostic criteria for serious contagious severe acute respiratory syndrome].

OBJECTIVE: To analyze the clinical diagnostic criteria for serious severe acute respiratory syndrome (SARS) in Guangdong retrospectively discriminant with SARS database, and to screen out the sensitive warning factors in predicting the outcome. METHODS: Four hundred and two SARS patients were selected based on the diagnostic criteria for SARS from Ministry of Health, China. Of them, 358 SARS patients were selected as their clinical manifestations conformed to the diagnostic criteria of serious SARS. The study subjects were divided into two groups. One group consisted of the patients with serious SARS (358 patients), and they either underwent invasive or non-invasive mechanical ventilation or died of the disease. The remaining 44 SARS patients constituted the non-serious SARS group. Taking the lowest value of oxygen index (OI) as the main index, the OI was categorized into 3 classes, namely< or =200 mm Hg (1 mm Hg=0.133 kPa) as 1,200-300 mm Hg as 2, and >300 mm Hg as 3. According to this index, the seriousness and the prognosis were analyzed. RESULTS: OI less than 300 mm Hg were identified as the unequivocal serious SARS patients, and the mistake judgement rate was 6.800%. Furthermore mortality and complications were compared with Logistic regression, and questionable SARS patients were excluded. The results showed that the patients identified with OI less than 300 mm Hg had worse outcome than the original ones diagnosed with criteria of Ministry of Health. CONCLUSION: OI less than 300 mm Hg in patients with ALI meet the diagnostic criteria of serious SARS better, and it can be taken as a prognostic criterion in clinic.

China↗
PubMed2006

[Phrenic nerve conduction of obstructive sleep apnea-hypopnea syndrome patients].

OBJECTIVE: To investigate the significance of phrenic nerve conduction time (PNCT) and diaphragm compound muscle action potential (CMAP) detection in the assessment of severity and response to treatment in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients. METHODS: Sixteen healthy volunteers (control group), 8 primary snorers (snorer group), 14 mild-moderate OSAHS patients (mild-moderate group) and 18 severe OSAHS patients (severe group) were recruited for the study from January to July in 2005. Multi-pair esophageal electrodes were used to measure PNCT and CMAP of diaphragm in response to unilateral magnetic stimulation. The study was repeated in 5 OSAHS patients after effective nCPAP treatment for at least 2 months. RESULTS: The PNCT in severe OSAHS group was (8.9 +/- 1.2), (7.9 +/- 1.5) ms respectively, which was significantly longer than those in the control group (6.5 +/- 0.7), (6.0 +/- 0.5) ms, snorer group (6.5 +/- 1.2), (6.0 +/- 0.8) ms and mild-moderate group (7.3 +/- 1.0), (6.3 +/- 0.7) ms. The amplitude of diaphragm CMAP was (1.4 +/- 0.4), (1.4 +/- 0.3) mV in mild-moderate group and (0.9 +/- 0.4), (1.1 +/- 0.6) mV in severe group, which was significantly lower than those in the control group (2.3 +/- 0.9), (2.1 +/- 0.9) mV and snorer group (1.9 +/- 0.5), (2.1 +/- 0.7) mV, and severe patients have significantly lower CMAP than mild-moderate patients. The PNCT and CMAP of both sides for all subjects correlated significantly with oxygen desaturation index and apnea-hypopnea index. The PNCT shortened significantly after effective nCPAP treatment, which was (8.6 +/- 0.6) ms, (7.4 +/- 0.5) ms for left side and (7.8 +/- 0.6) ms, (6.5 +/- 0.5) ms for right side. CONCLUSION: PNCT and CMAP detection with multi-pair esophageal electrodes in response to unilateral magnetic stimulation may be useful for the severity assessment and evaluation of response to effective treatment in OSAHS patients.

Action Potentials↗
PubMed2005

Evaluation by indirect immunofluorescent assay and enzyme linked immunosorbent assay of the dynamic changes of serum antibody responses against severe acute respiratory syndrome coronavirus.

BACKGROUND: Severe acute respiratory syndrome coronavirus (SARS-CoV) is a newly emerging virus that gives rise to SARS patients with high rates of infectivity and fatality. To study the humoral immune responses to SARS-CoV, the authors evaluated IgG and IgM specific antibodies in patients' sera. METHODS: Two methods, enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescent assay (IFA), were used to detect specific serum IgG and IgM against SARS-CoV in 98 SARS patients and 250 controls consisting of patients with pneumonia, health-care professionals and healthy subjects. The serum antibody profiles were investigated at different times over one and a half years in 18 of the SARS patients. RESULTS: The sensitivity and specificity of ELISA for detecting IgG against SARS-CoV were 100.0% and 97.2% and for IgM 89.8% and 97.6% respectively; the figures using IFA for IgG were 100.0% and 100.0% and for IgM 81.8% and 100.0% respectively. During the first seven days of the antibodies trace test, no IgG and IgM were detected, but on day 15, IgG response increased dramatically, reaching a peak on day 60, remaining high up to day 180 and decreasing gradually until day 540. On day 15, IgM was detected, rapidly reached a peak, then declined gradually until day 180 when IgM was undetectable. CONCLUSION: The detection of antibodies against SARS virus is helpful in the clinical diagnosis of SARS.

Adult↗
PubMed2005

[Changes in pulmonary function in severe acute respiratory syndrome patients during convalescent period].

OBJECTIVE: To investigate the changes and pattern of pulmonary function in severe acute respiratory syndrome (SARS) patients during convalescent period. METHODS: Pulmonary function tests were performed in 26 SARS convalescent patients regularly every 3 months after their discharge from hospital. The significance of changes in pulmonary function indexes was analyzed. RESULTS: Restrictive pulmonary ventilation function and diffusing dysfunction of the lung were found in one third of the patients during third to sixth month from onset. There was a little improvement in forced vital capacity (FVC), one second forced expiratory volume (FEV(1.0)), functional residual capacity (FRC) and residual volume (RV) as convalescent period was prolonged, but no difference was found between different stages (3-6 months, 6-9 months, 9-12 months, 12-15 months and 15-17 months). Meanwhile, the FEV(1.0)/FVC showed no significant change. However, there was an obvious improvement in total lung capacity (TLC) and diffusing capacity of the lung for carbon monoxide (DLCO) with the elapse of time, and also a significant difference was found between the later stage and the earlier stage. CONCLUSION: Pulmonary dysfunction is found among some SARS patients after convalescence presenting mainly as restrictive ventilatory function and diffusing capacity abnormality. These dysfunctions would improve gradually with the elapse of time.

Adult↗
PubMed2005

[Measurement of diaphragm compound muscle action potential with magnetic stimulation of the phrenic nerve and multipara esophageal electrode in intensive care unit].

OBJECTIVE: To investigate whether magnetic stimulation of the phrenic nerve and multipara esophageal electrode can be used to measure diaphragm compound muscle action potential (CMAP) in intensive care unit (ICU). METHODS: Ten normal subjects and 10 patients in ICU were studied. A newly designed multipara esophageal catheter with 5 pairs of electrodes was used to record the diaphragm CMAP elicited by magnetic stimulation and transcutaneous electrical stimulation of the phrenic nerve. RESULTS: Good quality CMAPs were obtained from normal subjects and patients in ICU. In normal subjects, the phrenic nerve conduction time (PNCT) and amplitude of the diaphragm CMAP measured with electrical stimulation [(7.2 +/- 0.8) ms, (1.52 +/- 0.40) mV] were similar to those measured with magnetic stimulation [(7.1 +/- 0.8) ms, (1.56 +/- 0.38) mV, all P > 0.05, pooled left and right values]. The amplitude of the diaphragm CMAP in patients [(0.73 +/- 0.38) mV] was much smaller than that in normal subjects [(1.58 +/- 0.38) mV, P < 0.01, pooled left and right values]. CONCLUSION: This study suggests that magnetic stimulation combined with a multipara esophageal electrode could be a useful technique in assessing diaphragm function in ICU.

Action Potentials↗
PubMed2004

[Report on the investigation of lower extremity osteonecrosis with magnetic resonance imaging in recovered severe acute respiratory syndrome in Guangzhou].

OBJECTIVE: To report the occurrence of lower extremity avascular abnormalities in 124 cases of recovered severe acute respiratory syndrome (SARS) health care workers of four hospitals in Guangzhou and preliminary investigate the correlation with the treatment of steroid. METHODS: 124 health care workers with recovered SARS from four hospitals in Guangzhou were examined with MR imaging of the lower extremity including bilateral hips and knees. In 124 health care workers, 38 cases have not treated with steroid, while 86 cases have treated with varied dosage. The imaging protocol was consisted of screening and full examination. Coronal T1-weighted imaging and short tau inversion recovery sequence were defined as the screening examination. The full examination was defined as images from the screening examination plus three additional imaging sequences: transverse and coronal T2-weighted imaging and short tau inversion recovery sequence. RESULTS: In 86 health care workers, 5 cases were found positive in the lower extremity. Osteonecrosis was found in 3 cases. One was involved in bilateral femoral head, and another was unilateral femoral head, and the remaining one was bilateral femoral heads and unilateral femoral condyle and tibial condyle. Bilateral femoral and tibial marrow edema were found in one case. Femoral infarction with significant calcification occurred in one health care worker. Logistic regression analysis indicated that the presence of avascular abnormalities was related with maximum daily dosage. CONCLUSION: Osteonecrosis definitely exists in the minority of health care workers with recovered SARS in Guangzhou, who had treated with steroid. The maximum daily dosage of steroid may significantly influence on the occurrence of avascular abnormalities.

Adolescent↗
PubMed2003

[Management of critical severe acute respiratory syndrome and risk factors for death].

OBJECTIVE: To investigate the management of critical severe acute respiratory syndrome (SARS) and possible risk factors for death. METHODS: Thirty-three patients with SARS referred to Guangzhou Institute of Respiratory Disease (GIRD) between December 2002 and March 2003 were studied retrospectively. Paired t-test using statistical software SPSS 10.0 was employed to compare the respiratory frequency and pulse O(2) saturation (SpO(2)) before and after noninvasive ventilation with continuous positive airway pressure (CPAP) on the 33 patients. Among them, 18 patients who presented with SpO(2) of 90% - 93% at rest under O(2) inhalation 5 L/min were further recorded for their SpO(2) during slight physical movement and CPAP. The possible death-related risk factors including age, underlying diseases, leucocytosis, thrombocytopenia, and lymphopenia were analyzed by the Mantel-Haenszel chi(2) test. RESULTS: The respiratory frequencies were significantly decreased and SpO(2) was improved in the 33 patients after one hour of noninvasive ventilation. The SpO(2) in the latter 18 patients fell during slight physical movement and improved one hour after CPAP (p < 0.01). The RRs of the five death predictors concerning thrombocytopenia, age (> 50 yrs, underlying diseases, leucocytosis, and lymphopenia were 25.83, 8.57, 6.40, 1.64, and 1.17, respectively, with the 95% CI of 3.64 - 183.59, 1.94 - 37.83, 1.75 - 23.33, 0.38 - 7.05 and 0.16 - 8.48, respectively. Management with corticosteroids effectively ameliorated and suppressed the development of pulmonary fibrosis. CONCLUSIONS: Noninvasive ventilation relieves dyspnea and SpO(2) in patients with critical SARS, and should also be employed in those with SpO(2) of 90% - 93% at rest under O(2) inhalation 5 L/min. Noninvasive as an add-on management may probably cut down on the dosage and duration of corticosteriod therapy. Among 5 possible risk factors, 3 were recognized as death-related, turning out to be thrombocytopenia, age (> 50 yrs) and underlying diseases.

Adrenal Cortex Hormones↗
PubMed2003

[Severe acute respiratory syndrome in 78 patients: a retrospective study].

OBJECTIVE: To analyze the clinical features of severe acute respiratory syndrome (SARS) and the diagnosis and treatment of the disease. METHODS: Seventy-eight patients with SARS referred to the Guangzhou Institute of Respiratory Diseases (GIRD), China from December 22, 2002 to March 2003 were studied retrospectively. The data reviewed included those of clinical manifestations, laboratory investigation and roentgenology. RESULTS: The patients consisted of 42 men and 36 women, aged 20 - 75 years (mean 37.5 +/- 11.6 years), including 44 infected health-care professionals. Clinical symptoms of these patients were fever (100%), coughing (88%), and dyspnea (80%). Routine blood test revealed WBCs <4.0 x 10(9)/L in 12 patients (15%), (4.0 -10.0) x 10(9)/L in 49 (63%), and over 10.0 x 10(9)/L in 17 (22%) [average (7.6 +/- 5.0) x 10(9)/L]. The level of neutrophilic granulocyte was 0.75 +/- 0.13 and that of lymphocyte was 0.18 +/- 0.11. Chest X-ray and CT scanning revealed changes related to pneumonia. The transmission of the disease was likely via close contact with contagious droplets. The prevalences of acute lung injury (ALI,37 patients) and acute respiratory distress syndrome (ARDS, 21 of the 37 patients) were considerably high among the patients. Seven patients who developed ARDS complicated with MODS died. CONCLUSIONS: A history of close contact, fever, X-ray signs of pneumonia and normal or lowered WBC counts are favorable for the diagnosis of SARS. Recognition of ALI as the important index for critical SARS and comprehensive supportive management are of paramount importance in decreasing the mortality of patients with SARS.

Adult↗
PubMed2003

[Roentgenography and CT appearance in patients with severe acute respiratory syndrome].

OBJECTIVE: To evaluate the appearance and dynamic change of chest roentgenography and CT in patients with severe acute respiratory syndrome (SARS). METHODS: Serial roentgenography and CT of 61 confirmed SARS patients were analyzed. RESULTS: The onset symptom was fever in all patients. In the early phase of SARS, the main abnormal appearance was single or bilateral localized patchy clouding opacity on roentgenography, which progressed rapidly. The area of opacity peaked at about 2 weeks, involving the majority area of the lung in 57% of the patients. The area involved was correlated with the severity of clinical symptoms. The opacity disappeared gradually in 5 weeks in 84% of the patients. Lungs complicated infection were found in 6 patients with a prolonged duration of the illness. Among the 61 patients, 4 died. CT scan was performed in 16 SARS patients in the recovery phase, of whom 13 showed lung fibrosis. CONCLUSIONS: Lung infiltration in early phase develops rapidly and involves most area of the lung in advanced phase in most SARS patients. Lungs fibrosis was found in some patients in the recovery phase.

Adult↗
PubMed2002

[A computer processing system for bronchoscopes images].

A new equipment of a computer multimedia system combined with a bronchoscope is presented here, which is able to provide active images with a high definition, image capture, synchronized video recording and playback during bronchoscopy. Its operation is easy and its quality is reliable. It is an advanced product for endoscopies and is worth while to be applied to clinical application.

Algorithms↗