Can ketamine be used for procedural sedation in a hypotensive, non‑fasted female patient?

Ketamine for Procedural Sedation in a Hypotensive, Non-Fasted Patient

Yes, ketamine is the optimal sedative choice for this patient—it uniquely preserves protective airway reflexes despite non-fasted status and provides hemodynamic stability in hypotension, unlike propofol or benzodiazepines which would be contraindicated.

Why Ketamine is Ideal for This Clinical Scenario

Non-Fasted Status: Ketamine's Unique Airway Protection

Ketamine, unlike other sedatives, helps preserve protective airway reflexes, making it the preferred agent when fasting guidelines cannot be followed. 1

• The 2019 multidisciplinary consensus guideline explicitly states: "When such a delay [for fasting] is not feasible, consider the use of dissociative sedation, as unlike other sedatives ketamine can be safely administered." 1
• No aspiration events have been reported with ketamine alone (except in compromised neonates), despite its association with vomiting and laryngospasm. 1
• Non-compliance with fasting guidelines was not identified as a risk factor for aspiration in either anesthesia or procedural sedation literature. 1
• Propofol is the most common sedative associated with aspiration during procedural sedation, making it a poor choice for non-fasted patients. 1

Hypotension: Ketamine's Hemodynamic Advantages

Ketamine provides cardiovascular stimulation rather than depression, making it superior to all other sedatives in hypotensive patients. 2

• A 2022 ICU study demonstrated that ketamine resulted in significantly less clinically significant hypotension compared to propofol or dexmedetomidine (34.6% vs 63.5%, P<0.001). 2
• Ketamine produced a smaller absolute decrease in systolic blood pressure (26.5 mm Hg vs 42.0 mm Hg, P<0.001) compared to propofol/dexmedetomidine. 2
• In multivariate analysis, receipt of propofol or dexmedetomidine was the only independent predictor of negative hemodynamic events (OR 3.3,95% CI 1.7-6.1). 2
• However, caution is warranted: Patients with shock index ≥0.9 (pulse rate/SBP) showed blunted hypertensive responses to ketamine, with 26% developing hypotension versus only 2% in low shock index patients. 3

Practical Dosing and Administration

Intravenous Route (Preferred if IV Access Available)

• Initial dose: 1-2 mg/kg IV administered slowly over 60 seconds. 4
• The FDA label specifies that rapid administration may result in respiratory depression and enhanced vasopressor response—slow administration is critical in hypotensive patients. 4
• Average dose of 2 mg/kg produces 5-10 minutes of surgical anesthesia within 30 seconds. 4

Intramuscular Route (If No IV Access)

• Dose: 4-5 mg/kg IM produces adequate sedation in 3-4 minutes, lasting 12-25 minutes. 1
• A reduced-dose protocol of 2 mg/kg IM has shown 87% efficacy for severe agitation with no intubations required. 5
• IM ketamine can be safely administered without IV access, which is particularly valuable when vascular access is difficult in hypotensive patients. 1

Critical Safety Monitoring Requirements

Airway Management Preparedness

• Emergency airway equipment (bag-valve mask, oral/nasal airways) must be immediately available. 4
• Providers must have expertise in airway management, as laryngospasm occurred in 0.9% (4/431) of pediatric cases and apnea in 0.5% (2/431). 1
• Brief apnea around the time of injection is common, though ketamine is generally a respiratory stimulant. 6
• Laryngospasm and airway obstruction are reported but significant cardiorespiratory adverse events are rare. 6

Hemodynamic Monitoring

• Continuously monitor blood pressure, heart rate, and oxygen saturation throughout the procedure and recovery. 1
• In hypotensive patients, calculate the shock index (pulse/SBP) before administration—if ≥0.9, expect blunted hypertensive response and prepare for potential hypotension. 3
• Have vasopressors immediately available if shock index is elevated. 3

Antisialagogue Consideration

• The FDA label recommends administering an antisialagogue prior to induction due to potential for increased salivation. 4
• However, this may be omitted in urgent situations where procedural sedation cannot be delayed.

Common Pitfalls to Avoid

Dosing Errors

• Never administer the 100 mg/mL concentration IV without proper dilution—dilute with equal volume of sterile water or normal saline. 4
• Avoid rapid IV push in hypotensive patients, as this increases risk of respiratory depression and exaggerated vasopressor response. 4

Emergence Reactions

• Dysphoric emergence phenomena occur in 10-20% of adult patients. 6
• Administer a benzodiazepine (e.g., midazolam 1-2 mg IV) if clinically indicated for prevention of neuropsychological manifestations during emergence. 4
• Benzodiazepines are effective in both preventing and managing these reactions. 6

Contraindications in This Patient

• None of the absolute contraindications apply: Ketamine is specifically recommended when fasting cannot be achieved and in hemodynamically unstable patients. 1
• The combination of hypotension and non-fasted status makes propofol, benzodiazepines, and dexmedetomidine all relatively contraindicated. 1, 2

Post-Procedure Recovery

• Most adverse events (92%) occur during the procedure, with serious events occurring a median of 2 minutes after final medication dosing. 1
• No primary serious adverse effects occurred >25 minutes after final medication administration in pediatric studies. 1
• Continue monitoring for at least 30 minutes after the procedure, as respiratory depression can occur up to 30 minutes post-administration. 7