Are diabetic patients on insulin (intravenous insulin) at risk for aspiration during anesthesia?

Diabetic Patients on Insulin and Aspiration Risk During Anesthesia

Diabetic patients on insulin are not inherently at higher risk for aspiration during anesthesia unless they have additional risk factors such as diabetic autonomic neuropathy or are taking medications like GLP-1 receptor agonists that delay gastric emptying. 1

Risk Assessment for Diabetic Patients

Diabetes alone does not automatically classify a patient as high risk for aspiration. The following factors should be evaluated:

Primary Risk Factors

• Diabetic autonomic neuropathy (DAN): Can lead to delayed gastric emptying and presence of undigested food particles despite fasting 2
• Medications affecting gastric emptying:
  • GLP-1 receptor agonists (e.g., semaglutide, liraglutide) significantly delay gastric emptying 1
  • Intravenous insulin itself is not identified as a specific aspiration risk factor

Additional Risk Factors to Consider

• Duration of diabetes (>10 years increases risk of autonomic neuropathy) 2
• Emergency surgery (higher risk than elective procedures) 1
• Upper gastrointestinal symptoms
• Obesity
• Procedures using sedation without airway protection 1

Practical Management Approach

Pre-operative Assessment

1. Screen for autonomic neuropathy using cardiovascular autonomic function tests in long-standing diabetics 2
2. Medication review: Identify patients on GLP-1 receptor agonists
3. Fasting guidelines: Standard fasting times (6 hours for solids, 2 hours for clear liquids) are generally appropriate for uncomplicated diabetic patients 3, 4

Intraoperative Management

For patients with identified risk factors:

1. Airway management options:

   • Consider tracheal intubation rather than supraglottic airway device
   • Consider modified rapid sequence induction in high-risk patients 1
   • Head-up positioning for induction

2. Additional protective measures:

   • Consider prokinetic administration (e.g., erythromycin 3 mg/kg 1-2 hours before induction) 1
   • Consider gastric ultrasound to assess residual gastric volume before induction 1
   • Use of orogastric or nasogastric tubes before induction and extubation 1

Important Caveats

1. Evidence limitations: The true risk of aspiration in fasting patients with diabetes is not well established, with limited and sometimes contradictory data 5

2. Avoid excessive fasting: Prolonged fasting can lead to poor glycemic control, increased insulin resistance, and patient discomfort 3, 6

3. Point-of-care gastric ultrasound: Can be valuable for risk stratification in uncertain cases 1

4. Balanced approach: While taking appropriate precautions for high-risk patients, recognize that the overall incidence of clinically significant aspiration is low (1.4-6.0 per 100,000 anesthetics for elective general surgery) 4

Summary

Intravenous insulin administration alone does not significantly increase aspiration risk during anesthesia. Risk assessment should focus on identifying diabetic autonomic neuropathy, use of medications that delay gastric emptying (particularly GLP-1 receptor agonists), and other patient-specific factors. Standard fasting guidelines are appropriate for most diabetic patients, with additional precautions for those with identified risk factors.