Marco Marano1, Stefano Marano2, F John Gennari3. 1. Hemodialysis Unit, Maria Rosaria Clinic, Pompeii, Naples, Italy. 2. Department of Information and Electrical Engineering and Applied Mathematics, University of Salerno, Fisciano, Salerno, Italy. 3. University of Vermont, UVM Medical Center, 1 South Prospect St., Burlington, VT, USA.
Abstract
Background: Acid-base assessments in hemodialysis patients have been limited almost entirely to measurements of total CO 2 concentration, and assumptions have been made about the presence of acid-base disorders. To gain a fuller understanding of the acid-base status of stable hemodialysis patients, we analyzed measurements of pCO 2 , pH and HCO 3 - obtained in a cohort of chronic stable hemodialysis patients over a 5-year period. Methods: We reviewed acid-base measurements taken pre-dialysis from fistula blood in 53 outpatients receiving hemodialysis thrice weekly between 2008 and 2012. In these patients, pH and pCO 2 were measured using an onsite blood gas analyzer, and HCO 3 - was computed. Relevant clinical and laboratory data were obtained from medical records. Factors affecting serum HCO 3 - were identified. Simple and mixed acid-base disorders were diagnosed using accepted rules. Results: Serum HCO 3 - was affected by age, normalized protein catabolic rate, interdialytic weight gain and length of interval between treatments. As expected, metabolic acidosis was the most common acid-base disorder, but respiratory acid-base disturbances, as simple or complex disorders, were found in 41% of the measurements. Respiratory alkalosis was seen more frequently than respiratory acidosis, but the latter disorder was more commonly associated with serious comorbidities. Conclusions: Respiratory acid-base disorders are an important component of the acid-base abnormalities seen in hemodialysis patients and are not identified by measuring total CO 2 concentration; hence, complete acid-base measurements are needed to determine the components of hemodialysis patients' acid-base status that are contributing to mortality risk.
Background: Acid-base assessments in hemodialysis patients have been limited almost entirely to measurements of total CO 2 concentration, and assumptions have been made about the presence of acid-base disorders. To gain a fuller understanding of the acid-base status of stable hemodialysis patients, we analyzed measurements of pCO 2 , pH and HCO 3 - obtained in a cohort of chronic stable hemodialysis patients over a 5-year period. Methods: We reviewed acid-base measurements taken pre-dialysis from fistula blood in 53 outpatients receiving hemodialysis thrice weekly between 2008 and 2012. In these patients, pH and pCO 2 were measured using an onsite blood gas analyzer, and HCO 3 - was computed. Relevant clinical and laboratory data were obtained from medical records. Factors affecting serum HCO 3 - were identified. Simple and mixed acid-base disorders were diagnosed using accepted rules. Results: Serum HCO 3 - was affected by age, normalized protein catabolic rate, interdialytic weight gain and length of interval between treatments. As expected, metabolic acidosis was the most common acid-base disorder, but respiratory acid-base disturbances, as simple or complex disorders, were found in 41% of the measurements. Respiratory alkalosis was seen more frequently than respiratory acidosis, but the latter disorder was more commonly associated with serious comorbidities. Conclusions: Respiratory acid-base disorders are an important component of the acid-base abnormalities seen in hemodialysis patients and are not identified by measuring total CO 2 concentration; hence, complete acid-base measurements are needed to determine the components of hemodialysis patients' acid-base status that are contributing to mortality risk.
Authors: Javier Enrique Cely; Oscar G Rocha; María J Vargas; Rafael M Sanabria; Leyder Corzo; Roberto E D'Achiardi; Eduardo A Zúñiga Journal: Int J Nephrol Date: 2018-11-18
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