Surgical Critical Care: Acid-Base Disorders – Physiologic Changes
Acidosis
Pulmonary Changes
- Increased Respiratory Rate
- Right-Shift of Oxygen-Hemoglobin Dissociation Curve – Decreased Affinity
Cardiovascular Changes
- Net Increased Cardiac Output
- Acidosis Directly Decreases Contractility
- However, Sympathoadreal Effects Cause Increased Preload, Heart Rate & Contractility
- Increased Risk of Arrhythmia
- Decreased Systemic Vascular Resistance & Arterial Vasodilation
- Decreased Responsiveness to Catecholamines
Hematologic Changes
- Coagulopathy – Impaired Clotting Factor Function
- Increased Red Blood Cell Size
- Decreased Red Blood Cell Rheology (Flow) – Contributes to Rouleaux Formation
- Impaired Platelet Aggregation – Effect of Hyperchloremia
Renal Changes
- Decreased Bicarbonate Secretion
- Increased Renal Ammonia Production & Secretion
- Diuresis
Electrolyte Changes
- Hyperkalemia – Intracellular Shifts
- Hypercalcemia – Decreased Calcium Binding to Albumin & Increased Renal Wasting
Other Changes
- Cerebral Vasodilation & Increased Intracranial Pressure
- Nausea & Vomiting
Alkalosis
Pulmonary Changes
- Decreased Respiratory Rate
- Left-Shift of Oxygen-Hemoglobin Dissociation Curve – Increased Affinity
Cardiovascular Changes
- Increased Contractility
- Increased Risk of Arrhythmia
- Increased Systemic Vascular Resistance & Arterial Vasoconstriction
Hematologic Changes
- Minimal Effects on Coagulation
Renal Changes
- Increased Bicarbonate Secretion
Electrolyte Changes
- Hypokalemia – Intracellular Shifts
- Hypocalcemia – Increased Calcium Binding to Albumin
Other Changes
- Cerebral Vasoconstriction & Decreased Intracranial Pressure