A patient arrives at the emergency room with low arterial pressure, reduced tissue turgor, and the following arterial blood values:
$\mathrm{pH}=7.69$
$\left[\mathrm{HCO}_{3}{ }^{-}\right]=57 \mathrm{mEq} / \mathrm{L}$
$\mathrm{PCO}_{2}=48 \mathrm{~mm} \mathrm{Hg}$
Which of the following responses would also be expected to occur in this patient?

Question

Quizplus · Accepted Answer

[IX D 2; Table 5.8]. First, the acid-base disorder must be diagnosed. Alkaline $\mathrm{pH}$, with increased $\mathrm{HCO}_{3}{ }^{-}$and increased $\mathrm{Pco}_{2}$, is consistent with metabolic alkalosis with respiratory compensation. The low blood pressure and decreased turgor suggest extracellular fluid (ECF) volume contraction. The reduced $\left[\mathrm{H}^{+}\right]$in blood will cause intracellular $\mathrm{H}^{+}$to leave cells in exchange for extracellular $\mathrm{K}^{+}$. The appropriate respiratory compensation is hypoventilation, which is responsible for the elevated $\mathrm{Pco}_{2} . \mathrm{H}^{+}$excretion in urine will be decreased, so less titratable acid will be excreted. $\mathrm{K}^{+}$secretion by the distal tubules will be increased because aldosterone levels will be increased secondary to ECF volume contraction.

A Patient Arrives at the Emergency Room with Low Arterial pH=7.69\mathrm{pH}=7.69pH=7.69

A Patient Arrives at the Emergency Room with Low Arterial $\mathrm{pH}=7.69$