Biomedical subjects

W W Tsai

Publications and source records attributed to W W Tsai.

3 recordsLinked to original sources

PubMed1996

Urinary PCO2 for hemodynamically unstable patients.

BACKGROUND: Gastric intramural pH (pHi) derived from gastric PCO2 has been successfully used to assess splanchnic ischemia for patients with unstable hemodynamics, but with some limitations. Urinary bladder, also an easily accessible hollow viscus, should provide as a useful route for the same purpose. However, no study has used urinary PCO2 to evaluate the adequacy of perfusion in critically ill patients. METHODS: Fifty patients admitted to intensive care unit were included and divided into hemodynamically stable and unstable groups. Several parameters such as arterial pressure, dopamine dosage, heart rate, serum lactate, arterial blood gas, urinary PCO2, and concentrations of Na, K and Cl in urine were measured. Patients with some other renal or pre-renal conditions that might affect urinary PCO2 were excluded. RESULTS: Urinary PCO2 was markedly higher (78.6 +/- 9.9 vs. 43.1 +/- 1.7 mmHg, p < 0.0001) in unstable group. Serum anion gap level, dopamine dosage and heart rate were significantly higher and PaO2/FiO2 ratio as well as mean arterial pressure was lower in unstable group. Serum lactate, arterial pH and other parameters failed to distinguish between groups. Dopamine dosage significantly correlated with urinary PCO2 (r = 0.5357, p = 0.0149) in unstable group. CONCLUSIONS: With careful selection of patients, urinary PCO2 can effectively differentiate hemodynamically unstable patients from stable ones. It also correlates significantly with dopamine dosage in patients with unstable hemodynamics.

Aged↗

PubMed1994

Revised estimates of diagnostic test sensitivity and specificity in suspected biliary tract disease.

BACKGROUND: The purpose of this study was to estimate the sensitivity and specificity of diagnostic tests for gallstones and acute cholecystitis. METHODS: All English-language articles published from 1966 through 1992 about tests used in the diagnosis of biliary tract disease were identified through MEDLINE. From 1614 titles, 666 abstracts were examined and 322 articles were read to identify 61 articles with information about sensitivity and specificity. Application of exclusion criteria based on clinical and methodologic criteria left 30 articles for analysis. Cluster-sampling methods were adapted to obtain combined estimates of sensitivities and specificities. Adjustments were made to estimates that were biased because the gold standard was applied preferentially to patients with positive test results. RESULTS: Ultrasound has the best unadjusted sensitivity (0.97; 95% confidence interval, 0.95 to 0.99) and specificity (0.95; 95% confidence interval, 0.88 to 1.00) for evaluating patients with suspected gallstones. Adjusted values are 0.84 (0.76 to 0.92) and 0.99 (0.97 to 1.00), respectively. Adjusted and unadjusted results for oral cholecystogram were lower. Radionuclide scanning has the best sensitivity (0.97; 95% confidence interval, 0.96 to 0.98) and specificity (0.90; 95% confidence interval, 0.86 to 0.95) for evaluating patients with suspected acute cholecystitis; test performance is unaffected by delayed imaging. Unadjusted sensitivity and specificity of ultrasound in evaluating patients with suspected acute cholecystitis are 0.94 (0.92 to 0.96) and 0.78 (0.61 to 0.96); adjusted values are 0.88 (0.74 to 1.00) and 0.80 (0.62 to 0.98). CONCLUSIONS: Ultrasound is superior to oral cholecystogram for diagnosing cholelithiasis, and radionuclide scanning is the test of choice for acute cholecystitis. However, sensitivities and specificities are somewhat lower than commonly reported. We recommend estimates that are midway between the adjusted and unadjusted values.

Acute Disease↗

PubMedDate not supplied

Point-of-care versus central laboratory testing: an economic analysis in an academic medical center.

A cost-effectiveness study was conducted to determine time and labor costs for point-of-care (POC) versus central laboratory testing. A prospective, observational time and motion study was carried out at a teaching hospital located in Philadelphia, Pennsylvania. The cohort consisted of 210 patients presenting to the emergency department who were triaged at the urgent or emergent level during a 4-week period. Patients who had blood drawn for a seven-chemistry profile (Chem-7), which includes analysis of sodium, potassium, chloride, carbon dioxide, blood urea nitrogen, glucose, and creatinine, or for cell blood count (CBC) tests as part of regular care, also had an additional split sample drawn for POC analysis of sodium, potassium, chloride, blood urea nitrogen, glucose, and/or hematocrit. Blood drawn for POC analysis did not require additional needlestick(s), nor did it alter regular care procedures. Physicians and all emergency department staff participating in the care of the patients were blinded to POC test results. Main outcome measures included test turn-around time (TAT), physician determination of impact of rapid TAT and laboratory values on therapeutic approach, and cost per test for POC versus central laboratory testing. POC TAT was a mean of 8 minutes (time from blood drawn to results shown on the POC device display). Central laboratory TAT was a mean of 59 minutes (time from blood drawn to entry of results into mainframe computer). Therapeutic TAT was a mean of 1 hour and 25 minutes (time from blood drawn to analysis in central laboratory, to when the physician viewed test results). After therapeutic course of care was decided for the patient, physicians reported that POC testing, independent of other rate-limiting steps, would have resulted in earlier therapeutic action for 40 of 210 (19.0%) patients. The cost per test for Chem-7 and CBC tests was $11.14 and $9.48, respectively. The cost per test for POC analysis ranged from $14.37 to $16.67, depending on the POC test volume (estimated volume based on 20% to 50% of emergency department patients that had either Chem-7 or CBC test done applied over the useful life of the POC testing equipment) and the personnel (nurse or emergency department technician) who performed the test. With an increasing volume of POC tests performed per unit time, costs for POC testing would be reduced substantially. POC test costs are volume dependent under current reimbursement mechanisms for emergency department patient care services, for example, fee-for-service payment.(ABSTRACT TRUNCATED AT 400 WORDS)

Academic Medical Centers↗