Does a patient with CT evidence of a high-grade small bowel obstruction, soft abdominal distention, and mild diffuse tenderness require placement of a nasogastric (NG) tube prior to induction of anesthesia with a rapid sequence intubation (RSI) technique?

NG Tube Placement Prior to RSI in High-Grade SBO

Yes, place an NG tube prior to induction of anesthesia with RSI technique in this patient with CT-confirmed high-grade small bowel obstruction, even with relatively benign physical examination findings. 1

Rationale for NG Tube Placement

The Society of Critical Care Medicine explicitly advises NG decompression when the benefit outweighs the risk in patients undergoing RSI who are at high risk of regurgitation of gastric contents. 1 Your patient meets multiple high-risk criteria:

• CT evidence of high-grade SBO creates a mechanical obstruction preventing normal gastric emptying, regardless of current symptom severity 1
• Gastric decompression reduces intragastric pressure and volume, thereby lowering the likelihood and severity of emesis and pulmonary aspiration during RSI 1
• High-grade SBO patients have fluid and gas accumulation proximal to the obstruction, creating a "full stomach" scenario even without active vomiting 2

Why Physical Exam Findings Are Misleading

The relatively benign presentation (soft abdomen, mild tenderness, no active vomiting) does not eliminate aspiration risk in this scenario:

• CT findings take priority over physical examination when determining aspiration risk in bowel obstruction 1
• Point-of-care ultrasound literature demonstrates increased regurgitation risk with estimated gastric fluid volume greater than 1.5 mL/kg, which is likely present in high-grade SBO regardless of distension severity 1
• The absence of severe symptoms does not indicate an empty stomach in mechanical obstruction 2

Clinical Decision Algorithm

Proceed with NG tube placement if:

• CT confirms high-grade SBO (>90% diagnostic accuracy) 1
• Patient requires emergency surgery
• RSI is planned for airway management

The NG tube should be placed BEFORE induction to:

• Decompress gastric contents accumulated proximal to the obstruction 1
• Minimize aspiration risk during the vulnerable period of RSI when airway reflexes are abolished 1
• Remove the mechanical barrier to gastric emptying that persists regardless of symptom severity 2

Important Caveats

Weigh complications of NG insertion against benefits:

• Nasal bleeding, gagging/vomiting during insertion, esophageal perforation, and inadvertent tracheal placement can occur 1
• However, in confirmed high-grade SBO requiring emergency surgery, the aspiration risk during RSI substantially outweighs insertion complications 1

If the patient actively vomits or gags during NG insertion:

• This paradoxically confirms the need for decompression
• Consider brief delay with head-up positioning and suction availability
• Do not abandon the attempt—the aspiration risk during RSI remains high without decompression 1

Why This Recommendation Differs from Routine Practice

While research shows that routine NG decompression in SBO may increase pneumonia risk and hospital length of stay in the postoperative setting 3, this evidence applies to patients managed conservatively or after surgery is completed. The pre-induction period during RSI represents a uniquely high-risk window where airway protective reflexes are pharmacologically abolished, making aspiration prevention paramount. 1

The 2023 SCCM guidelines specifically address this pre-induction period and recommend NG decompression based on aspiration risk, not routine practice. 1 High-grade SBO with planned emergency surgery meets their criteria for "benefit outweighs risk." 1