A 2-month-old infant is admitted with hypertrophic pyloric stenosis and is scheduled for pyloromyotomy. The infant has been vomiting for the past week and shows signs of dehydration. What is the priority nursing intervention before surgery?

Gastric decompression via nasogastric tube is the priority preoperative intervention to prevent aspiration and reduce gastric distension before pyloromyotomy. Other interventions are important but secondary to immediate aspiration risk.

Core Nursing Explanation Key Concept Analysis: This question assesses the priority preoperative nursing care for an infant with Hypertrophic Pyloric Stenosis (HPS). HPS is characterized by hypertrophy of the pyloric muscle, leading to gastric outlet obstruction. The key pathophysiological problem is that ingested formula cannot pass into the duodenum, resulting in Projectile, non-bilious vomiting. This leads to significant fluid and electrolyte losses, specifically a loss of hydrogen and chloride ions, causing a Hypochloremic, hypokalemic metabolic alkalosis. The priority before the corrective surgery (pyloromyotomy) is managing the immediate risk of Aspiration from a persistently full and distended stomach.

Answer Rationale: Key Point! The priority intervention is Insert nasogastric tube for gastric decompression. The infant's stomach is chronically full due to the obstruction. This poses a significant aspiration risk, especially during induction of anesthesia for surgery. Decompressing the stomach via an NG tube is a direct, immediate action to mitigate this life-threatening risk. It also provides comfort and allows for accurate assessment of residual gastric contents.

Distractor Analysis:
• Watch out for confusion! Option 1: While correcting the fluid and electrolyte deficit is critically important, it is not the priority in the immediate preoperative context. Administering oral fluids to an obstructed stomach is contraindicated as it will likely be vomited, worsening dehydration and aspiration risk. Fluid resuscitation must be done intravenously.
• Option 2: Positioning is a supportive measure but does not address the root cause of the aspiration risk—the full stomach. Prone positioning is not standard for aspiration prevention in this acute setting and may not be safe for an unstable infant.
• Option 4: Continuous cardiac monitoring is important for detecting arrhythmias related to electrolyte imbalances (like hypokalemia). However, this is a monitoring intervention, not an immediate, active intervention to treat the primary problem (gastric distension and aspiration risk). Monitoring follows correction and stabilization.

Related Concepts: The nursing process dictates addressing the most immediate life-threatening issue first (Airway, Breathing, Circulation). Here, the risk to the airway (aspiration) is paramount. Preoperative care for HPS follows a strict sequence: 1) NPO (Nothing by mouth), 2) NG decompression, 3) IV fluid and electrolyte correction, and then 4) surgery.
Concept Summary • Disease: Hypertrophic Pyloric Stenosis – Gastric outlet obstruction in infants. • Classic Symptom: Projectile, non-bilious vomiting. • Metabolic Imbalance: Hypochloremic, hypokalemic metabolic alkalosis. • Diagnostic Test: Palpable "olive" mass in RUQ, ultrasound confirmation. • Definitive Treatment: Pyloromyotomy. • Pre-op Priority: NPO & Gastric decompression (NG tube) to prevent aspiration.
Side-by-Side Comparison!

Intervention	Rationale & Priority	Why It's Not the Top Priority Here
NG Tube Insertion	Directly addresses the immediate aspiration risk from gastric distension. Essential for safe anesthesia.	N/A - This is the correct priority.
IV Fluid/Electrolyte Correction	Corrects dehydration and metabolic alkalosis. Crucial for physiological stability.	Must be done IV, not PO. Important but follows securing the airway risk.
Cardiac Monitoring	Monitors for arrhythmias from electrolyte imbalances (e.g., hypokalemia).	A monitoring tool, not an active treatment for the primary immediate threat.

Anatomy, Physiology & Pharmacology Points • Anatomy: The Pylorus is the muscular valve between the stomach and duodenum. Hypertrophy blocks this passage.
• Physiology: Vomiting loses gastric acid (HCl), leading to loss of H+ (causing alkalosis) and Cl- (hypochloremia). Potassium is also lost in urine and vomitus.
• Pharmacology: Pre-op medications are typically given IV. No oral medications are administered due to the obstruction.
Memory Tips • Acronym: For HPS priorities, think "Decompress, then Rehydrate (Drip), then Operate."
• Mnemonic: "Projectile Vomiting = Pyloric Problem. Prevent Aspiration First!"
High-Frequency NCLEX Topics This is a classic NCLEX pediatric surgery question. It tests:
1. Priority Setting (Airway risk vs. fluid deficit).
2. Understanding of pathophysiology linked to intervention (obstruction → NG tube).
3. Knowing that oral intake is contraindicated in obstructive GI conditions.
Watch Out for Question Variations! • The question could shift to: "Which electrolyte imbalance should the nurse monitor for?" (Answer: Hypokalemia, Hypochloremia, Metabolic Alkalosis).
• Or: "What is the most important postoperative nursing intervention?" (Answer: Gradually resume feedings as ordered, monitor for vomiting).
• Or: "The nurse palpates the infant's abdomen. What finding is characteristic of HPS?" (Answer: A firm, olive-shaped mass in the right upper quadrant).

Nursing Clinical Practice Guide Clinical Scenario: You are the nurse admitting 2-month-old "Leo" to the pediatric surgical unit. His parents report he has been vomiting forcefully after every feeding for 5 days. He is fussy, has sunken fontanelles, and few wet diapers. The surgeon confirms HPS via ultrasound and schedules a pyloromyotomy for tomorrow morning.

Nursing Intervention Strategy:
1. Immediate Action (Priority): Insert a Nasogastric (NG) tube to intermittent low suction. Measure and document the character and amount of gastric output (will be undigested formula). Keep the infant NPO.
2. Assessment: Obtain vital signs, weight, assess for signs of dehydration (skin turgor, mucous membranes, fontanelles), and monitor strict I&O (Intake and Output).
3. Collaborative Care: Initiate IV access and administer isotonic IV fluids (e.g., Normal Saline with potassium chloride) as prescribed to correct dehydration and electrolyte imbalances. Monitor lab values (Electrolytes, BUN, Creatinine).
4. Pre-op Preparation: Provide parent education about the surgery and the reason for the NG tube and IV. Position the infant on the right side or upright to facilitate gastric emptying by gravity, per protocol.

Patient Safety and Precautions:
• Never attempt to give oral fluids or medications.
• Secure the NG tube well to prevent dislodgement and check placement before any irrigation.
• Monitor for complications of NG suction, such as electrolyte imbalance or mucosal injury.
• Post-operatively, follow the specific feeding advancement protocol (e.g., start with small amounts of clear fluids or electrolyte solution, then advance to formula).
Nursing Procedure & Medication Flow NG Tube Insertion in an Infant (Key Steps):
1. Measure tube length (nose to ear lobe to xiphoid process).
2. Lubricate the tip.
3. Insert gently through the nostril; if the infant gags or coughs, stop and check placement.
4. Confirm placement by aspirating gastric contents and checking pH (gastric pH < 5). Key Point! A chest X-ray is the gold standard for initial placement confirmation in infants.
5. Secure the tube and connect to ordered suction (often intermittent low suction).

IV Fluid Administration: Use an infusion pump for precise rate control. Rehydration is typically done over 24-48 hours to avoid fluid overload.
A Word from Your Senior Nurse "In pediatric nursing, especially with surgical infants, your vigilance is their lifeline. That NG tube isn't just a piece of plastic—it's what keeps their airway safe from silent aspiration. When you see 'projectile vomiting' in an infant, let your mind immediately go to 'obstruction' and 'NPO.' Connecting the pathophysiology (the blocked pylorus) to your nursing action (decompressing the stomach) is what makes you more than a task-doer; it makes you a thinking nurse who understands the 'why' behind every intervention. This deep understanding is exactly what the NCLEX tests and what will make you invaluable at the bedside."