Clinic for Ruminants, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Clinic for Ruminants with Ambulatory and Herd Health Services at the Centre for Clinical Veterinary Medicine, LMU Munich, Oberschleißheim, Germany.
J Vet Intern Med. 2021 Jan;35(1):644-654. doi: 10.1111/jvim.16031. Epub 2021 Jan 15.
Marked strong ion (metabolic) acidosis in neonatal diarrheic calves usually is corrected by IV administration of NaHCO . The distribution space for IV-administered bicarbonate, called the apparent bicarbonate space (ABS), appears to depend on initial plasma bicarbonate concentration (cHCO ) and varies considerably in calves.
To determine whether ABS was associated with initial plasma cHCO and other acid-base variables.
Twenty-five neonatal diarrheic calves with acidemia and metabolic acidosis.
Prospective observational study using a convenience sample. Calves received NaHCO (10 mmol/kg) and glucose (1.4 mmol/kg) IV in a crystalloid solution at 25 mL/kg over 60 minutes. The ABS (L/kg) was calculated at 4 time points over 2 hours after the end of the infusion. The relationship between ABS and initial acid-base variables was characterized using nonlinear, linear, and stepwise regression.
The median value for ABS calculated from the initial plasma cHCO increased from 0.53 L/kg (range, 0.40-0.79) at the end of IV infusion to 0.96 L/kg (range, 0.54-1.23) 120 minutes later. Data obtained at the end of infusion provided the best fit to initial plasma cHCO and jugular venous blood Pco , such that: ABS = 0.41 + 1.06/cHCO and ABS = 0.87-0.0082 × Pco .
The observed median value for ABS of 0.53 L/kg in our study was similar to the empirically used value of 0.6. However, ABS values varied widely and were increased in calves with severe metabolic acidosis. We therefore recommend calculating ABS using the initial plasma cHCO or venous blood Pco , if respective measurements are available.
新生腹泻犊牛的明显强离子（代谢）酸中毒通常通过 IV 给予碳酸氢钠来纠正。IV 给予的碳酸氢盐的分布空间，称为表观碳酸氢盐空间（ABS），似乎取决于初始血浆碳酸氢盐浓度（cHCO），并且在犊牛中变化很大。
确定 ABS 是否与初始血浆 cHCO 和其他酸碱变量相关。
25 头患有酸中毒和代谢性酸中毒的新生腹泻犊牛。
使用便利样本进行前瞻性观察研究。犊牛在 60 分钟内以 25 mL/kg 的速度接受 IV 输注结晶溶液中的碳酸氢钠（10 mmol/kg）和葡萄糖（1.4 mmol/kg）。在输液结束后 2 小时内的 4 个时间点计算 ABS（L/kg）。使用非线性、线性和逐步回归来描述 ABS 与初始酸碱变量之间的关系。
从 IV 输注结束时的初始血浆 cHCO 计算得出的 ABS 的中位数从 0.53 L/kg（范围 0.40-0.79）增加到 120 分钟后的 0.96 L/kg（范围 0.54-1.23）。输液结束时获得的数据与初始血浆 cHCO 和颈静脉血 Pco 拟合最好，即：ABS = 0.41+1.06/cHCO 和 ABS = 0.87-0.0082×Pco。
在我们的研究中，观察到的 ABS 中位数为 0.53 L/kg，与经验使用的 0.6 相似。然而，ABS 值差异很大，并且在代谢性酸中毒严重的犊牛中增加。因此，如果有相应的测量值，我们建议使用初始血浆 cHCO 或静脉血 Pco 计算 ABS。
