Electrocardiographic findings in 130 hospitalized neonatal calves with diarrhea and associated potassium balance disorders

Abstract

BackgroundHyperkalemia in neonatal diarrheic calves can potentially result in serious cardiac conduction abnormalities and arrhythmias.ObjectivesTo document electrocardiographic (ECG) findings and the sequence of ECG changes that are associated with increasing plasma potassium concentrations (cK+) in a large population of neonatal diarrheic calves.AnimalsOne hundred and thirty neonatal diarrheic calves (age ≤21 days).MethodsProspective observational study involving calves admitted to a veterinary teaching hospital.ResultsHyperkalemic calves (cK+: 5.8‐10.2, blood pH: 6.55‐7.47) had significantly (P < .05) longer QRS durations as well as deeper S wave, higher T wave, and higher ST segment amplitudes in lead II than calves, which had both venous blood pH and cK+ within the reference range. The first ECG changes in response to an increase in cK+ were an increase in voltages of P, Ta, S, and T wave amplitudes. Segmented linear regression indicated that P wave amplitude decreased when cK+ >6.5 mmol/L, S wave amplitude voltage decreased when cK+ >7.4 mmol/L, QRS duration increased when cK+ >7.8 mmol/L, J point amplitude increased when cK+ >7.9 mmol/L, and ST segment angle increased when cK+ >9.1 mmol/L. P wave amplitude was characterized by a second common break point at cK+ = 8.2 mmol/L, above which value the amplitude was 0.Conclusions and Clinical ImportanceHyperkalemia in neonatal diarrheic calves is associated with serious cardiac conduction abnormalities. In addition to increased S and T wave amplitude voltages, alterations of P and Ta wave amplitudes are early signs of hyperkalemia, which is consistent with the known sensitivity of atrial myocytes to increased cK+.

Measurement of urine pH and net acid excretion and their association with urine calcium excretion in periparturient dairy cows

“…We used mixed-models segmented linear regression (Gonçalves et al, 2016;Trefz et al, 2018) to characterize the urine [NH 4 + ]-NAE relationship for all urine samples, adjusting for the effect of cow, with μ 0 representing the random background coefficient assuming the distribution of random effects to be normal with mean (μ 0 ) = 0 and variance = s2e. A mixed models approach was used because up to 10 data points were obtained from each cow.…”

Intravenous and Oral Fluid Therapy in Neonatal Calves With Diarrhea or Sepsis and in Adult Cattle

“…Although isotonic and containing a sodium concentration of 154 mmol/L which is beneficial in calves with diarrhea as they are frequently hyponatremic ( 25 ), the effective SID of the solution is 0 mmol/L and consequently the solution is acidifying when administered intravenously ( Figure 5 ). Moreover, 0.9% NaCl solution does not contain potassium, and neonatal calves with diarrhea have been thought for many years to be potassium deficient ( 59 ), despite some calves having hyperkalemia ( 9 , 45 , 60 , 61 ). The assumption that diarrheic calves have whole body depletion of potassium has been recently challenged in a study of calves with acute diarrhea and marked dehydration and acidemia, in that diarrheic calves had similar skeletal muscle potassium concentrations to healthy calves ( 62 ).…”

Clinical utility of plasma progesterone and blood and plasma glucose concentrations in predicting parturition in Holstein cows

“…We used mixed-model segmented nonlinear regression (PROC NLMIXED, SAS 9.4, SAS Institute Inc., Cary, NC; Gonçalves et al, 2016;Trefz et al, 2018) to characterize the plasma [prog]-time relationship during the last 3 d of gestation and the first 24 h after parturition. This permitted adjustment for the effect of cow on the model estimates, because up to 4 data points were obtained from each cow.…”