Vomiting which saline we give
Reading File
Finding Sources
Reading File
Reading File
Vomiting → Normal Saline (0.9% NaCl)
In vomiting, we give Normal Saline (0.9% NaCl / Isotonic Saline).
Why Normal Saline?
Prolonged vomiting causes loss of:
- H⁺ (hydrogen ions)
- Cl⁻ (chloride ions)
- K⁺ (potassium, secondarily)
- Fluid volume
This results in Hypochloremic, Hypokalemic Metabolic Alkalosis.
Since chloride is the primary ion lost, it must be replaced with a chloride-rich solution — which is Normal Saline (contains 154 mEq/L of Na⁺ and 154 mEq/L of Cl⁻).
Treatment Steps
| Step | Action |
|---|---|
| 1st | Volume resuscitation with Normal Saline (0.9% NaCl) |
| 2nd | Potassium replacement — only after adequate urine output is established |
Potassium is replaced after confirming urine output because giving K⁺ before adequate renal function risks hyperkalemia.
Why not Lactated Ringer's (LR)?
LR does not contain enough chloride to correct hypochloremic alkalosis. Normal saline is preferred specifically because of its high chloride content.
Sources:
- Schwartz's Principles of Surgery, 11th Ed — on metabolic alkalosis from vomiting: "Treatment includes replacement of the volume deficit with isotonic saline and then potassium replacement once adequate urine output is achieved."
- Sleisenger & Fordtran's Gastrointestinal and Liver Disease — "The loss of fluid, hydrogen ions, and chloride ions in the vomitus leads to hypochloremic, hypokalemic metabolic alkalosis. The patient should be volume resuscitated with normal saline followed by potassium replacement once urine output is adequate."
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