Effects of pH on Potassium

Lorch

Zitzl

et al. 2015

BackgroundNeonatal diarrheic calves have a clear negative potassium balance because of intestinal losses and decreased milk intake but in the presence of acidemia, they usually show normokalemic or hyperkalemic plasma concentrations.ObjectivesTo assess whether marked hypokalemia occurs in response to the correction of acidemia and dehydration and to identify factors that are associated with this condition.AnimalsEighty‐three calves with a clinical diagnosis of neonatal diarrhea.MethodsProspective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate, 0.9% saline and 40% dextrose infusion solutions.ResultsThe proportion of hypokalemic calves after 24 hours of treatment (19.3%) was twice as great as it was on admission to the hospital. Plasma K+ after 24 hours of treatment was not significantly correlated to venous blood pH values at the same time but positively correlated to venous blood pH values on admission (r = 0.51, P < .001). Base excess on admission (Odds ratio [OR] = 0.81, 95% confidence interval [CI] = 0.70–0.94), duration of diarrhea (OR = 1.37, 95% CI = 1.05–1.80), milk intake during hospitalization (OR = 0.54, 95% CI = 0.37–0.79) and plasma sodium concentrations after 24 hours (OR = 1.12, 95% CI = 1.01–1.25) were identified to be independently associated (P < .05) with a hypokalemic state after 24 hours of treatment.Conclusions and Clinical ImportanceFindings of this study suggest that marked depletion of body potassium stores is evident in diarrheic calves that suffered from marked metabolic acidosis, have a low milk intake and a long history of diarrhea.

Section: Discussionmentioning

confidence: 99%

Risk Factors for the Development of Hypokalemia in Neonatal Diarrheic Calves

Lorch

Zitzl

et al. 2015

“…Interestingly, there are also studies that documented a potassium‐lowering effect of sodium bicarbonate in acidotic humans 44, 45. As an explanation for the existent discrepancies a recent review article39 discussed that the potassium‐lowering effect of sodium bicarbonate depends on the presence of metabolic acidosis and more importantly on the degree of intracellular acidosis as intracellular Na + entry by Na + –H + exchange and Na + ‐bicarbonate cotransport is greater when intracellular pH and

{HCO}_{3}^{-}

are reduced. This would explain why sodium bicarbonate has a marked potassium‐lowering effect in acidemic neonatal diarrheic calves.…”

Section: Discussionmentioning

confidence: 99%

Effect of Intravenous Small‐Volume Hypertonic Sodium Bicarbonate, Sodium Chloride, and Glucose Solutions in Decreasing Plasma Potassium Concentration in Hyperkalemic Neonatal Calves with Diarrhea

Constable

Lorenz

2017

BackgroundHyperkalemia is a frequently observed electrolyte imbalance in dehydrated neonatal diarrheic calves that can result in skeletal muscle weakness and life‐threatening cardiac conduction abnormalities and arrhythmias.HypothesisIntravenous administration of a small‐volume hypertonic NaHCO3 solution is clinically more effective in decreasing the plasma potassium concentration (cK) in hyperkalemic diarrheic calves than hypertonic NaCl or glucose solutions.AnimalsTwenty‐two neonatal diarrheic calves with cK >5.8 mmol/L.MethodsProspective randomized clinical trial. Calves randomly received either 8.4% NaHCO3 (6.4 mL/kg BW; n = 7), 7.5% NaCl (5 mL/kg BW; n = 8), or 46.2% glucose (5 mL/kg BW; n = 7) IV over 5 minutes and were subsequently allowed to suckle 2 L of an electrolyte solution. Infusions with NaHCO3 and NaCl provided an identical sodium load of 6.4 mmol/kg BW.ResultsHypertonic NaHCO3 infusions produced an immediate and sustained decrease in plasma cK. Hypertonic glucose infusions resulted in marked hyperglycemia and hyperinsulinemia, but cK remained unchanged for 20 minutes. Between 30 and 120 minutes after initiation of treatment, the most marked decrements in cK from baseline occurred in group NaHCO3, which were significantly (P < .05) larger during this period of time than in calves in group NaCl, but not group glucose. After 120 minutes, the mean decrease in cK from baseline was −26 ± 10%, −9 ± 8%, and −22 ± 6% in groups NaHCO3, NaCl, and glucose, respectively.Conclusions/Clinical ImportanceSmall‐volume hypertonic NaHCO3 infusions appear to have clinical advantages for the rapid resuscitation of hyperkalemic diarrheic calves, compared to hypertonic NaCl or glucose solutions.

“…First, our findings strongly suggest the presence of a compartmental shift of potassium ions in response to intravenous administration of hypertonic sodium bicarbonate. Based on the current understanding of cellular transport processes involved in extrarenal K + balance, increases in extracellular HCO 3 − concentration enhance cellular Na + uptake by a Na + ‐HCO 3 − cotransport and Na + ‐H + exchange which consequently stimulates Na + , K + ‐ATPase activity and consequently net cellular K + uptake 22. Secondly, administration of undiluted 8.4% sodium bicarbonate solution resulted in a profound osmotically driven plasma volume expansion as indicated by marked decreases of total protein concentrations.…”

Section: Discussionmentioning

confidence: 99%

“…This is particularly based on the results of studies in dogs with experimentally induced hyperkalemia24 and human patients with end‐stage renal disease25, 26 where alkalinization after intravenous administration of sodium bicarbonate was reported to be ineffective in lowering blood K + concentrations. However, it was discussed that the plasma potassium‐lowering effect of sodium bicarbonate depends on the presence of a metabolic acidosis and more importantly on the degree of intracellular acidosis 22. This could also explain the finding of a study,13 where the plasma potassium‐lowering effect of orally administered sodium bicarbonate solutions in non‐acidemic calves was predominantly related to plasma volume expansion rather than to increases in base excess.…”

Section: Discussionmentioning

confidence: 99%

Effects of Alkalinization and Rehydration on Plasma Potassium Concentrations in Neonatal Calves with Diarrhea

Lorch

Zitzl

et al. 2015

BackgroundIncreased plasma potassium concentrations (K+) in neonatal calves with diarrhea are associated with acidemia and severe clinical dehydration and are therefore usually corrected by intravenous administration of fluids containing sodium bicarbonate.ObjectivesTo identify clinical and laboratory variables that are associated with changes of plasma K+ during the course of treatment and to document the plasma potassium‐lowering effect of hypertonic (8.4%) sodium bicarbonate solutions.AnimalsSeventy‐one neonatal diarrheic calves.MethodsProspective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate (250–750 mmol), 0.9% saline (5–10 L), and 40% dextrose (0.5 L) infusion solutions.ResultsInfusions with 8.4% sodium bicarbonate solutions in an amount of 250–750 mmol had an immediate and sustained plasma potassium‐lowering effect. One hour after the end of such infusions or the start of a sodium bicarbonate containing constant drip infusion, changes of plasma K+ were most closely correlated to changes of venous blood pH, plasma sodium concentrations and plasma volume (r = −0.73, −0.57, −0.53; P < .001). Changes of plasma K+ during the subsequent 23 hours were associated with changes of venous blood pH, clinical hydration status (enophthalmos) and serum creatinine concentrations (r = −0.71, 0.63, 0.62; P < .001).Conclusions and Clinical ImportanceThis study emphasizes the importance of alkalinization and the correction of dehydration in the treatment of hyperkalemia in neonatal calves with diarrhea.