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?
1Administer oral electrolyte solution to correct fluid deficit
2Position the infant prone to prevent aspiration
3Insert nasogastric tube for gastric decompression✓ 정답
4Begin continuous cardiac monitoring for arrhythmias
해설
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.
Understanding the Clinical Picture
A 2-month-old infant with hypertrophic pyloric stenosis (HPS) presents with a history of projectile, non-bilious vomiting over the past week. The pathophysiology involves hypertrophy of the pyloric muscle, leading to gastric outlet obstruction. Persistent vomiting results in the loss of hydrochloric acid from the stomach. This sequence causes a specific set of metabolic derangements: hypochloremic, hypokalemic metabolic alkalosis. The accompanying dehydration can range from mild to severe, and the infant is at risk for electrolyte imbalances that may predispose them to cardiac arrhythmias. However, the immediate preoperative priority targets the root cause of ongoing fluid and electrolyte loss: the gastric distention and obstruction.
Prioritizing Preoperative Nursing Interventions
The question asks for the priority nursing intervention before surgery. Using clinical reasoning, the nurse must first address the physiological problem that is actively causing deterioration and could lead to immediate life-threatening complications, such as aspiration.
Analysis of the Correct Answer Option 3: Insert nasogastric tube for gastric decompression.
This is the correct priority action. In hypertrophic pyloric stenosis, the stomach is obstructed and often remains full of gastric contents and secretions that cannot pass into the duodenum. This poses a high risk of aspiration, especially in a dehydrated and weak infant. Decompressing the stomach with a nasogastric (NG) tube immediately reduces this risk and allows for accurate measurement of ongoing gastric losses. This step is a fundamental component of preoperative stabilization, as highlighted in case reports discussing anesthetic preparation for pyloromyotomy, where ensuring an empty stomach is critical before induction [3]. The consensus statement on pediatric anesthesia also underscores the importance of managing the unique physiological vulnerabilities of infants, where aspiration risk is a primary safety concern .
Analysis of Incorrect Options Option 1: Administer oral electrolyte solution to correct fluid deficit.
This is contraindicated. The infant has a gastric outlet obstruction, meaning any oral intake will not pass into the small intestine for absorption and will instead accumulate in the stomach, worsening distention and dramatically increasing the risk of vomiting and aspiration. Fluid and electrolyte correction in HPS is achieved exclusively through intravenous (IV) fluid therapy, not oral routes.
Option 2: Position the infant prone to prevent aspiration.
This is an unsafe practice. Current safe-sleep and aspiration-prevention guidelines for infants recommend the supine position for sleep. For an infant with active vomiting and a full stomach, the prone position does not reliably protect the airway and is associated with an increased risk of sudden infant death syndrome (SIDS). The correct nursing action to prevent aspiration is to place the infant in a semi-upright or side-lying position if vomiting occurs, but the definitive intervention is gastric decompression via an NG tube.
Option 4: Begin continuous cardiac monitoring for arrhythmias.
While this is an important intervention, it is not the priority. The severe electrolyte imbalances (hypokalemia) that result from prolonged vomiting can indeed lead to cardiac arrhythmias, making monitoring necessary. However, cardiac monitoring is a diagnostic and surveillance measure. It does not treat the underlying cause of the electrolyte loss. The priority is to stop the ongoing loss of gastric acid by decompressing the stomach, which is the source of the problem. The emergency medicine curriculum for pediatric gastrointestinal emergencies reinforces that stabilization begins with addressing the immediate anatomical and physiological insult . Once the NG tube is placed and IV fluid replacement is started, continuous cardiac monitoring is then established as part of comprehensive care.
References (research sources)
[3]
A rare occurrence of pyloric stenosis in an infant with osteogenesis imperfecta: Anesthetic implications.Research articleJagtap SR, Bakhshi RG, Jain A. (2014) · DOI: 10.4103/0970-9185.130064
Clinical Priority: Preoperative Management of Hypertrophic Pyloric Stenosis
A 2-month-old infant with hypertrophic pyloric stenosis (HPS) and dehydration is scheduled for pyloromyotomy. The immediate preoperative priority is to eliminate the risk of aspiration by decompressing the stomach. This directly addresses the ongoing physiological threat from gastric outlet obstruction.
Step 1: Immediate Gastric Decompression
Insert a nasogastric (NG) tube and connect to low intermittent suction to evacuate retained gastric contents and secretions.
Verify NG tube placement via auscultation, pH testing of aspirate, and measurement of tube length at the nares.
Maintain NPO status strictly; nothing by mouth until after surgical correction.
Step 2: Fluid and Electrolyte Resuscitation
After decompression, initiate intravenous (IV) fluid therapy as prescribed, typically with isotonic solutions (e.g., 0.9% sodium chloride) to correct dehydration.
Monitor serum electrolytes closely, particularly chloride and potassium, to correct the characteristic hypochloremic, hypokalemic metabolic alkalosis.
Add potassium to IV fluids only after adequate urine output is established to prevent hyperkalemia.
Step 3: Continuous Monitoring and Safety
Place the infant in a semi-upright or side-lying position to further reduce aspiration risk; prone positioning is contraindicated.
Initiate continuous cardiac monitoring to detect arrhythmias secondary to electrolyte imbalances (hypokalemia, hypocalcemia).
Monitor vital signs, intake and output, and daily weights to assess hydration status and response to therapy.
Nursing Rationale
The airway and breathing take precedence over circulation in this scenario. Gastric decompression directly protects the airway from aspiration of pooled gastric contents. Once the airway risk is mitigated, fluid and electrolyte correction can proceed safely. Surgery is scheduled only after metabolic alkalosis and dehydration are corrected to minimize perioperative risks.
Hypertrophic Pyloric Stenosis — A condition in infants where the pyloric muscle thickens, causing gastric outlet obstruction and projectile non-bilious vomiting.
Pyloromyotomy — A surgical procedure to incise the thickened pyloric muscle, relieving the obstruction in hypertrophic pyloric stenosis.
Gastric Decompression — The removal of stomach contents via a nasogastric tube to relieve distention and reduce the risk of aspiration.
Hypochloremic Hypokalemic Metabolic Alkalosis — An electrolyte and acid-base imbalance caused by loss of hydrochloric acid and potassium from persistent vomiting, common in pyloric stenosis.