What is the role of gastric decompression in cardiac arrest?

Role of Gastric Decompression in Cardiac Arrest

Gastric decompression should be performed in cardiac arrest patients who demonstrate gastric distention or are at high risk of regurgitation of gastric contents, as this can improve ventilation and reduce the risk of aspiration.

Rationale for Gastric Decompression

Gastric decompression serves two critical functions during cardiac arrest management:

1. Improving ventilation effectiveness

   • Positive-pressure ventilation during CPR can lead to gastric insufflation due to decreased pulmonary compliance and decreased lower esophageal sphincter tone 1
   • Gastric distention can elevate the diaphragm, restrict lung movement, and decrease respiratory system compliance 2
   • Severe gastric distention can cause ventilatory compromise that impedes effective resuscitation 1

2. Reducing aspiration risk

   • Positive-pressure ventilation in an unprotected airway may cause gastric insufflation and aspiration of gastric contents 2
   • Aspiration during cardiac arrest can lead to severe pulmonary complications if ROSC is achieved 3
   • Experimental evidence shows that aspiration occurs in a significant proportion of cases during CPR with various airway management techniques 4

When to Consider Gastric Decompression

Gastric decompression should be prioritized in the following scenarios:

• When visible gastric distention is present
• In patients with known risk factors for regurgitation:
  • Recent food intake
  • Gastroesophageal reflux disease
  • Bowel obstruction
  • Pregnancy
• When ventilation becomes difficult during resuscitation
• When gastric contents are detected in the oropharynx

Implementation of Gastric Decompression

Nasogastric Tube Decompression

The 2023 Society of Critical Care Medicine guidelines advise:

• NGT decompression when the benefit outweighs the risk in patients who are at high risk of regurgitation of gastric contents 2
• When the stomach is decompressed with an NGT, the intragastric pressure and gastric content volume may be decreased, lowering the likelihood and severity of emesis and pulmonary aspiration 2

Assessment Techniques

• Clinical assessment of abdominal distention
• Point-of-care ultrasound can help determine the need for and effectiveness of NGT 2
• Increased risk of regurgitation is present when ultrasound shows:
  • Solid gastric contents
  • Estimated total gastric fluid volume >1.5 mL/kg (with patient in right lateral decubitus position)
  • Presence of clear fluids (with patient in both supine and lateral decubitus positions) 2

Potential Complications and Considerations

• Complications of NGT insertion include nasal bleeding, gagging and vomiting, esophageal perforation, and tracheal placement 2
• Cricoid pressure has been traditionally used to reduce gastric inflation and aspiration risk, but evidence is mixed:
  • May reduce gastric inflation during bag-mask ventilation 2
  • Can impede ventilation in many patients and cause complete obstruction in up to 50% of patients 2
  • Can interfere with placement of supraglottic airways or intubation 2
  • The routine use of cricoid pressure in cardiac arrest is not recommended (Class III, LOE C) 2

Advanced Airway Management Considerations

• Endotracheal intubation offers superior protection against regurgitation and pulmonary aspiration compared to supraglottic airway devices or bag-valve ventilation 4
• If advanced airway placement is delayed or unsuccessful, gastric decompression becomes even more important when using bag-mask ventilation 2
• Airway management is required during prolonged cardiac arrest to facilitate ventilation and reduce the risk of gastric regurgitation and aspiration 2

Special Circumstances

In rare cases, cardiac arrest can be directly caused by gastric pathology:

• Acute intrathoracic gastric volvulus can cause cardiac arrest due to decreased venous return from mediastinal shift 5
• In such cases, immediate gastric decompression may be lifesaving and directly address the cause of arrest

Summary

Gastric decompression plays an important role in cardiac arrest management by improving ventilation effectiveness and reducing aspiration risk. While not explicitly mentioned in all resuscitation algorithms, it should be considered when gastric distention is present or when the patient is at high risk for regurgitation. The decision to perform gastric decompression should balance the potential benefits against the risks and time required for the procedure during the critical minutes of a resuscitation.