---

---

Question

Surgery is a major physiologic stress and often is accompanied by biochemical derangements that effect homeostasis in the post-operative period. Describe the most common clinical scenarios that can cause each of the four main acid-base imbalances in a post-surgical patient.

---

---

Answer

• Metabolic Acidosis
  • Lactic acidosis (HAGMA)
    • Under-resuscitation
    • Blood loss
  • Hyperchloremia (NAGMA)
    • High chloride load from NaCl
• Metabolic Alkalosis
  • Volume contraction and bicarbonate reabsorption
  • GI loss from NG tube suction or emesis
• Respiratory Acidosis
  • Opioid medications causing depressed respiratory drive
• Respiratory Alkalosis
  • Splinting from pain