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Biomedical subjects

Chee-Fah Chong

Publications and source records attributed to Chee-Fah Chong.

16 recordsLinked to original sources
PubMed2007

Silent myocardial ischemia in coronary artery disease patients under aspirin therapy presenting with upper gastrointestinal hemorrhage.

AIM: To identify the risk factors for myocardial ischemia in patients undergoing aspirin therapy for coronary artery disease (CAD) presenting with upper gastrointestinal hemorrhage and to ascertain the impacts on mortality and length of hospital stay. METHODS: Adults with CAD under aspirin therapy (100 mg once daily) presenting to the emergency department with upper gastrointestinal hemorrhage were retrospectively recruited and divided into group A (ischemia) and group B (non-ischemia). Charts were reviewed for various demographic, laboratory and outcome data. Electrocardiograms were interpreted blindly by a senior cardiologist. RESULTS: A total of 152 patients, 72.4% men and 27.6% women, were analyzed. Of these, 31 patients had ischemia and were placed in group A and 121 patients did not have ischemia and were in group B. Independent multivariate predictors of myocardial ischemia were history of triple vessel disease (odds ratio [OR], 9.24; 95% confidence interval [CI], 2.00-42.72), lower diastolic blood pressure (OR, 1.09; 95% CI, 1.02-1.16), lower hematocrit (OR, 1.41; 95% CI, 1.16-1.70), and higher blood urea nitrogen (OR, 0.94; 95% CI, 0.89-0.98). Patients with myocardial ischemia had significantly longer hospital length of stay (8.7 +/- 4.0 days vs 5.4 +/- 1.7 days; P < 0.001) and higher in-hospital mortality (16.1%vs 2.5%; P < 0.01) than did those without myocardial ischemia. CONCLUSION: Myocardial ischemia is a relatively common complication in CAD patients under aspirin therapy presenting with upper gastrointestinal hemorrhage. A history of CAD with triple vessel disease, higher blood urea nitrogen, lower diastolic blood pressure and lower hematocrit may help identify patients who are at increased risk of myocardial ischemia, which tends to be associated with higher in-hospital mortality and increased length of hospital stay.

Aged↗
PubMed2006

Development of a personal digital assistant-based wireless application in clinical practice.

PURPOSE: Our study aims to develop a personal digital assistant (PDA)-based wireless application in medical information processing by using Bluetooth and IEEE 802.11b wireless standards and SyncML codes. METHODS: In this study, an "integrated database access module" is used to provide a unified integrated access interface while consistency of wireless data transmission is achieved by using the standardized SyncML protocol. A prototype of the system has been developed, implemented, and tested for its mobility, usability, stability, and performance with questionnaire survey. RESULTS: Response time for browsing/searching was usually less than 3s. The average time intervals needed for data transmissions were 68.6+/-8.5s for Bluetooth and 47.0+/-4.8s for 802.11b. The five-point Likert scale (from 1=least to 5=most) questionnaire survey of 30 medical professionals yielded a high degree of satisfaction with the system's mobility (4.18+/-0.89), usability (4.69+/-0.90), stability (3.81+/-0.94), and performance (3.97+/-0.88). CONCLUSION: The results of our study suggested that PDA applications which exploit wireless communication are convenient and feasible in clinical practice.

Computers, Handheld↗
PubMed2005

Esophageal rupture due to Sengstaken-Blakemore tube misplacement.

The author presents three cases of esophageal rupture during the treatment of massive esophageal variceal bleeding with Sengstaken-Blakemore (SB) tube. In each case, simple auscultation was used to guide SB tube insertion, with chest radiograph obtained only after complete inflation of the gastric balloon. Two patients died of hemorrhagic shock and one died of mediastinitis. The author suggests that confirmation of SB tube placement by auscultation alone may not be adequate. Routine chest radiographs should be obtained before and after full inflation of the gastric balloon to confirm tube position and to detect tube dislocation.

Adult↗
PubMed2005

Applying an artificial neural network to predict total body water in hemodialysis patients.

BACKGROUND: Estimating total body water (TBW) is crucial in determining dry weight and dialytic dose for hemodialysis patients. Several anthropometric equations have been used to predict TBW, but a more accurate method is needed. We developed an artificial neural network (ANN) to predict TBW in hemodialysis patients. METHODS: Demographic data, anthropometric measurements, and multifrequency bioelectrical impedance analysis (MF-BIA) were investigated in 54 patients. TBW measured by MF-BIA (TBW-BIA) was the reference. The predictive value of TBW based on ANN and five anthropometric equations (58% of actual body weight, Watson formula, Hume formula, Chertow formula, and Lee formula) was evaluated. RESULTS: Predictive TBW values derived from anthropometric equations were significantly higher than TBW-BIA (31.341 +/- 6.033 liters). The only non-significant difference was between TBW-ANN (31.468 +/- 5.301 liters) and TBW-BIA (p = 0.639). ANN had the strongest Pearson's correlation coefficient (0.911) and smallest root mean square error (2.480); its peak centered most closely to zero with the shortest tails in an empirical cumulative distribution plot when compared with the other five equations. CONCLUSION: ANN could surpass traditional anthropometric equations and serve as a feasible alternative method of TBW estimation for chronic hemodialysis patients.

Adult↗
PubMed2005

Low plasma vasopressin/norepinephrine ratio predicts septic shock.

To evaluate if low plasma vasopressin and high norepinephrine concentrations predict grave prognosis of sepsis, a prospective sample of consecutive patients visiting the emergency department of a university teaching hospital who met the American College of Chest Physicians criteria of sepsis or severe sepsis was enrolled. Besides septic workup, we measured serum vasopressin and norepinephrine concentrations to correlate the impending outcome. One hundred eighty-two patients aged 27 to 99 years met the inclusive criteria and were classified as those with septic shock (n = 72), severe sepsis (n = 56), and those with sepsis only (n = 54) according to the outcome within 6 hours. Thirty healthy subjects were included as control. The plasma vasopressin level at baseline was significantly lower for those who finally developed septic shock (septic shock group, 3.6 +/- 2.5 pg/mL; 95% confidence interval [CI], 3.0-4.2 pg/mL; severe sepsis group, 21.8 +/- 4.1 pg/mL, 95% CI, 20.7-22.9 pg/mL; sepsis group, 10.6 +/- 6.5 pg/mL, 95% CI, 8.8-12.4 pg/mL, P < .001), whereas the norepinephrine level was highest for the same group (septic shock group, 3650 +/- 980 pg/mL, 95% CI, 3420-3880 pg/mL; severe sepsis group, 3600 +/- 1000 pg/mL, 95% CI, 3330-3870 pg/mL; sepsis group, 1720 +/- 320 pg/mL, 95% CI, 1630-1810 pg/mL). The vasopressin/norepinephrine ratio was significantly lower for the patients with final diagnosis of septic shock (P < .001). The mean interval between the time of samples drawn and the time of the most severe occurring sequelae was 2.4 +/- 0.8 hours. Receiver operating characteristic analysis revealed that the vasopressin/norepinephrine ratio 1 x 10(-3) had a sensitivity of 97% (95% CI, 90%-99%) and a specificity of 85% (95% CI, 78%-91%) for detecting impending septic shock. Low serum vasopressin/norepinephrine ratio can predict impending septic shock.

Adult↗
PubMed2004

Establishing a clinical decision rule of severe acute respiratory syndrome at the emergency department.

STUDY OBJECTIVE: In the absence of reliable rapid confirmatory tests during severe acute respiratory syndrome (SARS) endemics, we designed a 2-phase cohort study to establish a scoring system for SARS and to evaluate whether it could improve the sensitivity and specificity of the World Health Organization (WHO) criteria. METHODS: According to the clinical characteristics and initial laboratory findings of 175 suspected cases defined by the WHO criteria (20 confirmed as cases of SARS) in 3 university teaching hospitals in Taipei between March 1 and April 20, 2003, the scoring system for SARS was designed by multivariate analysis and stepwise logistic regression as the simple arithmetic sum of point values assigned to 7 parameters. We thereafter applied the scoring system for SARS to the consecutive 232 patients (the validation group) who met the WHO criteria of suspected cases from April 21 to May 22, 2003. Final diagnosis of SARS was determined by the results of real-time polymerase chain reaction and paired serum. RESULTS: The scoring system for SARS was defined as radiographic findings of multilobar or bilateral infiltrates (3 points), sputum monocyte predominance (3 points), lymphocytopenia (2 points), history of exposure (1 point), lactate dehydrogenase more than 450 U/L (1 point), C-reactive protein more than 5.0 mg/dL (1 point), and activated partial prothrombin time more than 40 seconds (1 point). Of the validation group, 60 patients (group A) were confirmed as having cases of SARS, and the other 172 (group B) patients tested negative for SARS. The total points of the scoring system for SARS at initial presentation were significantly higher in the SARS group (median 9; range 6 to 11) than in the non-SARS group (median 4; range 3 to 7; P<.001). At the cutoff value of 6 points, the sensitivity and specificity of the scoring system for SARS in diagnosing SARS were 100% and 93%, respectively. The positive and negative predictive values of the scoring system for SARS were 83% and 100%, respectively. CONCLUSION: The scoring system for SARS can provide a rapid and reliable clinical decision to help emergency physicians detect cases of SARS more accurately in the endemic area.

Blood Cell Count↗
PubMed2003

Stratification of adverse outcomes by preoperative risk factors in coronary artery bypass graft patients: an artificial neural network prediction model.

We constructed and internally validated an artificial neural network (ANN) model for prediction of in-hospital major adverse outcomes (defined as death, cardiac arrest, coma, renal failure, cerebrovascular accident, reinfarction, or prolonged mechanical ventilation) in patients who received "on-pump" coronary artery bypass grafting (CABG) surgery. We retrospectively analyzed a 5-year CABG surgery database with a final study population of 563 patients. Predictive variables were limited to information available before the procedure, and outcome variables were represented only by events that occurred postoperatively. The ANN's ability to discriminate outcomes was assessed using receiver-operating characteristic (ROC) analysis and the results were compared with a multivariate logistic regression (LR) model and the QMMI risk score (RS) model. A major adverse outcome occurred in 12.3% of all patients and 18 predictive variables were identified by the ANN model. Pairwise comparison showed that the ANN model significantly outperformed the RS model (AUC = 0.886 vs.0.752, p = 0.043). However, the other two pairs, ANN vs. LR models (AUC = 0.886 vs. 0.807, p = 0.076) and LR vs. RS models (AUC = 0.807 vs. 0.752, p = 0.453) performed similarly well. ANNs tend to outperform regression models and might be a useful screening tool to stratify CABG candidates preoperatively into high-risk and low-risk groups.

Cardiopulmonary Bypass↗