From the Research
Early ECG changes in non-bilious vomiting due to gastric outlet obstruction primarily reflect electrolyte disturbances, especially hypokalemia and metabolic alkalosis, which can lead to flattened or inverted T waves, the appearance of U waves, ST segment depression, and prolonged QT intervals. These changes are a result of persistent vomiting, leading to loss of potassium-rich gastric contents and subsequent activation of the renin-angiotensin-aldosterone system due to volume depletion, as well as metabolic alkalosis from the loss of hydrochloric acid in gastric secretions, further promoting potassium excretion by the kidneys 1. The severity of these ECG changes generally correlates with the degree of electrolyte disturbance, particularly potassium levels. Some key points to consider in the management of these patients include:
- Correction of the underlying obstruction
- Addressing fluid and electrolyte imbalances
- Potassium repletion to prevent cardiac complications, as hypokalemia can cause atrial premature complexes, and atrial fibrillation may occur 1. In the context of gastric outlet obstruction, it is essential to focus on the most critical aspect of management, which is correcting the underlying cause of the obstruction and addressing the resulting electrolyte imbalances, rather than solely focusing on the ECG changes. Given the options provided, the most appropriate answer is D) T wave sagging, as it is a common ECG finding associated with hypokalemia, which is a frequent electrolyte disturbance in patients with gastric outlet obstruction, as evidenced by the ECG changes described in the study 1.