Publications (118) View all
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Article: Item response analysis on an examination in anesthesiology for medical students in Taiwan: A comparison of one- and two-parameter logistic models.
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ABSTRACT: BACKGROUND: Student examinations are an essential component of medical education and item analyses are important to assess test quality. Among miscellaneous psychometric theories used for test analyses, item response theory is more flexible and versatile than other theories. This study aimed to apply item response models to analyze an anesthesiology examination for medical and dental students. METHODS: This examination included 50 items that were administered to 170 5(th)- and 6(th)-year medical and dental students. One- and two-parameter logistic (1-PL and 2-PL) item response models were used to conduct item analyses of the examination. Fit statistics were examined to exclude misfit items and evaluate test reliability. Goodness-of-fit analyses were used to select the model having the better fit to data. Examinee's ability and item difficulty were estimated and then expressed on the common scale. Potentially differential items were detected using logistic regression. RESULTS: The goodness-of-fit analysis revealed that, in our case, the 1-PL model was more suitable for item response analyses. No misfit item was noted and the test reliability was 0.81 (1-PL model). The mean examinee's ability was set at 0 by definition [standard deviation (SD) = 0.61] and the mean item difficulty was -2.08 (SD = 1.93). There were 24 items with a difficulty level lower than the least able examinee, and three items had a difficulty level higher than the most able examinee. Four potentially differential items were identified. CONCLUSION: Item response models are useful for medical test analyses and provide valuable information about model comparisons and identification of differential items other than test reliability, item difficulty, and examinee's ability.Journal of the Chinese Medical Association 04/2013; · 0.79 Impact Factor -
Article: Patient-machine interactions of intravenous patient-controlled analgesia in bilateral versus unilateral total knee arthroplasty: A retrospective study.
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ABSTRACT: BACKGROUND: Continuous passive motion after a major knee surgery optimizes functional prognosis, but causes severe pain. In this study, we assessed the effect of intravenous patient-controlled analgesia (IVPCA) on postoperative pain management in unilateral and bilateral total knee arthroplasty (TKA). METHODS: Data were collected retrospectively from a single medical center from March 2003 to October 2007. All patients who had undergone TKA were given general anesthesia, and the type of surgery that each patient received was planned according to individual needs. A total of 223 patients qualified for this study, with 174 patients in the unilateral TKA group. Data on patient demography, pain scores, and side effect scores were collected. Total dose consumption, demand, delivery doses, demand-to-delivery ratio, and infusion rate were collected from PCA machines and analyzed. RESULTS: The patient pain score and patient satisfaction showed no significant difference between the unilateral and bilateral TKA groups. The incidence of sedation (p < 0.001), nausea (p = 0.013), and vomiting (p = 0.044) during the postoperative 24-48-hour period was higher in the bilateral TKA group. Compared with the patients in the unilateral group, those in the bilateral group showed significantly greater dose consumption during the postoperative 6-12-, 12-18-, and 18-24-hour periods. They also showed more demand for medication during the postoperative 12-18- and 18-24-hour periods and received more bolus doses during the postoperative 12-18-, 18-24-, and 30-36-hour periods. In addition, there was also a significantly higher demand-to-delivery ratio for patients in the bilateral group during the postoperative 6-12-, 12-18-hour periods. CONCLUSION: In this study, we successfully demonstrated that our IVPCA protocol can provide adequate analgesia for patients after both bilateral and unilateral TKA. However, sedation, nausea, and vomiting occurred more frequently during the postoperative 24-48-hour period in patients who underwent bilateral than unilateral TKA. This may due of the increased number of bolus doses administered to the patients in the bilateral TKA group during the postoperative 12-18, 18-24, and 30-36-hour periods. Therefore, the initial infusion rates for patients undergoing bilateral TKA could be set at a lower threshold in order to reduce the incidence of these side effects.Journal of the Chinese Medical Association 04/2013; · 0.79 Impact Factor -
Article: Fluid management guided by stroke volume variation failed to decrease the incidence of acute kidney injury, 30-day mortality, and 1-year survival in living donor liver transplant recipients.
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ABSTRACT: Low central venous pressure (CVP) produced by fluid restriction has been applied to liver transplant recipients in order to decrease blood loss. However, CVP is not reliable for monitoring intravascular volume and ventricular filling. In addition, doubts remain over the association between fluid restriction and acute kidney injury (AKI). We tested the utility of stroke volume variation (SVV), derived from the FloTrac/Vigileo system, as a decision-making tool in fluid management. We examined the differences in fluid administration, urine output, postoperative AKI, and 30-day and 1-year survival rates between liver transplant recipients with fluid management guided by SVV and CVP. We retrospectively collected data on our liver transplant recipients with a Model for End-stage Liver Disease score less than 30 and serum creatinine lower than 1.5 mg/dL from 2007 to 2010. Recipients in 2007 and 2008 who received CVP-guided fluid management served as the control group. Recipients in 2009 and 2010 who received fluid administration triggered by SVV were recruited as the study group. The estimated blood loss, urine output, and fluid administered during the operation were recorded. Renal function was assessed using the RIFLE criteria on postoperative days 1 and 5. We also recorded the 30-day and 1-year survival. Significantly more diuretic use and urine output were noted in the control group in spite of similar fluid administration. However, there was no significant difference in blood loss, AKI, or 30-day and 1-year survival rates. The outcomes of living donor liver transplant patients who had fluid therapy guided by an SVV less than 10% were similar to those of patients who were given fluids to reach a CVP of 10 mmHg. Our findings suggest that the two measures of vascular filling are similar in liver transplant recipients with demographic characteristics similar to those of our patients.Journal of the Chinese Medical Association 12/2012; 75(12):654-9. · 0.79 Impact Factor -
Article: Use of higher thromboelastogram transfusion values is not associated with greater blood loss in liver transplant surgery.
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ABSTRACT: Plasma-containing products are given during the pre-anhepatic stage of liver transplant surgery to correct abnormal thromboelastogram (TEG) values and prevent blood loss due to coagulation defects. However, evidence suggests that abnormal TEG results do not always predict bleeding. We questioned what effect using higher TEG values to initiate treatment would have on blood loss. A single transfusion protocol was used for all patients who underwent liver transplantation between 2007 and 2010. Thirty-eight patients received coagulation products when standard TEG cutoff values were exceeded, whereas another 39 patients received coagulation products when the TEG values were 35% greater than normal. The results of postoperative coagulation tests for total blood loss and the use of blood products were compared for the 2 groups. When the critical TEG values for transfusion were higher, significantly fewer units of fresh frozen plasma (5.58 ± 6.49 versus 11.53 ± 6.66 U) and pheresis platelets (1.84 ± 1.33 versus 3.55 ± 1.43 U) were used. There were no differences in blood loss or postoperative blood product use. In conclusion, the use of higher critical TEG values to initiate the transfusion of plasma-containing products is not associated with increased blood loss. Further testing is necessary to identify what TEG value predicts bleeding due to a deficit in coagulation factors. Liver Transpl 18:1254-1258, 2012. © 2012 AASLD.Liver Transplantation 06/2012; 18(10):1253-7. · 3.39 Impact Factor -
Article: Effect of propofol on vascular reactivity in thoracic aortas from rats with endotoxemia.
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ABSTRACT: This study examined the effect of propofol on thoracic aortas isolated from endotoxic rats to assess endothelium-dependent and -independent relaxant responses. Adult male Wistar rats were assigned randomly to one of two groups, a saline control group or an experimental group treated with lipopolysaccharide (LPS, 10 mg/kg intravenously). At 6 hours after saline or LPS infusion, the thoracic aorta was excised and cut into 3-mm rings. Aortic rings with or without endothelium were suspended in organ baths for isometric tension recording. Both norepinephrine (NE)-induced vascular contraction and acetylcholine-induced vasodilation were attenuated in aortas from LPS-treated rats. Furthermore, preincubation with propofol caused a rightward shift in the NE concentration-response curve for aortas from LPS-treated rats compared to sham controls. The slow and sustained, but not the initial fast, contractile response to NE was significantly suppressed by propofol in LPS-treated aortas. In addition, vascular relaxation induced by propofol in LPS-treated aortas was partially suppressed by inhibitors of either nitric oxide (NO) synthase or soluble guanylate cyclase, but not by potassium channel inhibitors. These data suggest that propofol reduces the sensitivity to NE in aortic rings from endotoxic rats. This appears to be caused by (i) blockade of the extracellular calcium influx rather than a reduction in intracellular calcium release and (ii) an increased response to, at least in part, NO-cGMP in rat aortas.Journal of the Chinese Medical Association 06/2012; 75(6):262-8. · 0.79 Impact Factor
