Background: Few studies have investigated the relationship between serum total carbon dioxide (CO2) concentration and bicarbonate ion (HCO3-) concentration in patients undergoing hemodialysis. We determined the agreement and discrepancy between serum total CO2and HCO3- concentrations and the diagnostic accuracy of serum total CO2 for the prediction of low (HCO3- < 24 mEq/L) and high (HCO3- ≥ 24 mEq/L) bicarbonate concentrations in hemodialysis patients. Methods: One hundred forty-nine arteriovenous blood samples from 84 hemodialysis patients were studied. Multiple linear regression analysis was used to determine factors correlated with HCO3- concentration. Diagnostic accuracy of serum total CO2 was evaluated using receiver operating characteristic curve analysis and a 2 × 2 table. Agreement between serum total CO2 and HCO3- concentrations was assessed using Bland-Altman analysis. Results: Serum total CO2 concentration was closely correlated with HCO3- concentration (β = 0.858, P < 0.001). Area under the curve of serum total CO2 for the identification of low and high bicarbonate concentrations was 0.989. Use of serum total CO2 to predict low and high bicarbonate concentrations had a sensitivity of 100%, specificity of 50.0%, positive predictive value of 96.5%, negative predictive value of 100%, and accuracy of 96.6%. Bland-Altman analysis showed moderate agreement between serum total CO2 and HCO3- concentrations. Discrepancies between HCO3- and serum total CO2 concentrations (serum total CO2 - HCO3- ≤ -1) were observed in 89 samples. Conclusion Serum total CO2 concentration is closely correlated with HCO3- concentration in hemodialysis patients. However, there is a non-negligible discrepancy between serum total CO2 and HCO3- concentrations.

Background: Few studies have investigated the relationship between serum total carbon dioxide (CO2) concentration and bicarbonate ion (HCO3-) concentration in patients undergoing hemodialysis. We determined the agreement and discrepancy between serum total CO2and HCO3- concentrations and the diagnostic accuracy of serum total CO2 for the prediction of low (HCO3- < 24 mEq/L) and high (HCO3- ≥ 24 mEq/L) bicarbonate concentrations in hemodialysis patients. Methods: One hundred forty-nine arteriovenous blood samples from 84 hemodialysis patients were studied. Multiple linear regression analysis was used to determine factors correlated with HCO3- concentration. Diagnostic accuracy of serum total CO2 was evaluated using receiver operating characteristic curve analysis and a 2 × 2 table. Agreement between serum total CO2 and HCO3- concentrations was assessed using Bland-Altman analysis. Results: Serum total CO2 concentration was closely correlated with HCO3- concentration (β = 0.858, P < 0.001). Area under the curve of serum total CO2 for the identification of low and high bicarbonate concentrations was 0.989. Use of serum total CO2 to predict low and high bicarbonate concentrations had a sensitivity of 100%, specificity of 50.0%, positive predictive value of 96.5%, negative predictive value of 100%, and accuracy of 96.6%. Bland-Altman analysis showed moderate agreement between serum total CO2 and HCO3- concentrations. Discrepancies between HCO3- and serum total CO2 concentrations (serum total CO2 - HCO3- ≤ -1) were observed in 89 samples. Conclusion Serum total CO2 concentration is closely correlated with HCO3- concentration in hemodialysis patients. However, there is a non-negligible discrepancy between serum total CO2 and HCO3- concentrations.

Since students who would like to study Kampo medicine more have no opportunity to communicate each other in Northern Japanese Universities, we newly started joint study conferences held by medical students in 2013. The objectives of this paper are to report on these annually held student-based Kampo study conferences in the Hokkaido and Tohoku areas, and the ways each university studies Kampo medicine. In the conference, the students reported on their club activities. Then they studied the history of Kampo medicine and simulation of abdominal diagnosis, and performed group work on case reports together. The number of student participants in these conferences has tripled over 3 years from 18 to 58 (for a total of 111 participants). All members were satisfied with the content. And this reflects medical students' need for a wider perception of Kampo medicine, rather than a limited one gained in their university club activities. We hope this conference will play a major role in other nationwide student-based Kampo study conferences in the years to come.

BACKGROUND: We investigated the relationship between serum total carbon dioxide (CO₂) and bicarbonate ion (HCO₃⁻) concentrations in pre-dialysis chronic kidney disease (CKD) patients and devised a formula for predicting low bicarbonate (HCO₃⁻< 24 mmol/L) and high bicarbonate (HCO₃⁻ ≥ 24 mmol/L) using clinical parameters. METHODS: In total, 305 samples of venous blood collected from 207 pre-dialysis patients assessed by CKD stage (G1 + G2, 46; G3, 50; G4, 51; G5, 60) were investigated. The relationship between serum total CO₂ and HCO₃⁻ concentrations was analyzed using Pearson’s correlation coefficient. An approximation formula was developed using clinical parameters correlated independently with HCO₃⁻ concentration. Diagnostic accuracy of serum total CO₂ and the approximation formula was evaluated by receiver operating characteristic curve analysis and a 2 × 2 table. RESULTS: Serum total CO₂ correlated strongly with HCO₃⁻ concentration (r = 0.91; P < 0.001). The following approximation formula was obtained by a multiple linear regression analysis: HCO₃⁻ (mmol/L) = total CO₂ − 0.5 × albumin − 0.1 × chloride − 0.01 × (estimated glomerular filtration rate + blood glucose) + 15. The areas under the curves of serum total CO₂ and the approximation formula for detection of low bicarbonate and high bicarbonate were 0.981, 0.996, 0.993, and 1.000, respectively. This formula had superior diagnostic accuracy compared with that of serum total CO₂ (86.6% vs. 81.3%). CONCLUSION: Serum total CO₂ correlated strongly with HCO₃⁻ concentration in pre-dialysis CKD patients. An approximation formula including serum total CO₂ showed superior diagnostic accuracy for low and high bicarbonate compared with serum total CO₂.
Acid-Base Equilibrium ; Bicarbonates ; Carbon Dioxide ; Carbon ; Glomerular Filtration Rate ; Humans ; Linear Models ; Renal Insufficiency, Chronic ; ROC Curve