Metabolic acidosis/alkalosis

Respiratory alkalosis

Causes:

· characterised by decreases in PCO₂ (< 35 mm Hg) leading to decreased carbonic acid 2^o:

i) increased respiratory rate & depth 2^o

a) increased temperature [RR increases 10/min for each 1^o F]

b) hypoxia at high altitude

c) anxiety & tension

d) pain

e) CNS trauma

f) drugs eg aspirin

Metabolic alkalosis

Causes:

· characterized by

i) excessively high levels of base

a) antacid ingestion

· ii) depressed concentrations of acid

a) excessive output of stomach contents

eg vomiting, gastric suction

Signs & Symptoms

· excitation of CNS: hyperirritability & hightened reflexes

· elevation of respiratory rate & depth (Kussmaul respirations)

· tachycardia & arrhythmia

· hypocalcemia 2^o decreased ionisation in ECF-> carpopedal spasms, tetany, arrhythmias

· hypokalemia 2^o retention of H⁺ in kidneys in exchange for K⁺