What is the incidence of laryngospasm in adults receiving ketamine sedation?

Frequency of Laryngospasm in Adults During Ketamine Sedation

Laryngospasm during ketamine sedation in adults is exceedingly rare, occurring at a rate of approximately 1 in 883 sedations (4.2 per 1,000 sedations), and when it does occur, it is typically idiosyncratic and unpredictable rather than associated with specific clinical factors. 1

Incidence Data from High-Quality Evidence

The most robust data comes from a 2016 systematic review and meta-analysis of 9,652 adult procedural sedations in emergency departments, which identified only one case of laryngospasm in 883 ketamine sedations 1. This represents:

• Incidence rate: 4.2 per 1,000 sedations (0.42%) 1
• This makes laryngospasm one of the rarest serious adverse events with ketamine, far less common than hypoxia (40.2 per 1,000) or vomiting (16.4 per 1,000) 1

Context: Adult vs. Pediatric Populations

While the question specifically asks about adults, it's important to note the contrast with pediatric data, as this informs our understanding of ketamine's safety profile:

• In pediatric emergency department settings, laryngospasm rates are similarly low at 0.9-1.4% 2
• However, in higher-risk pediatric populations (gastroenterology procedures, ASA status III or greater), rates increased to 8.2% overall and 14% in preschoolers 2
• The adult data suggests comparable or potentially lower rates than standard pediatric ED use 1, 3

Clinical Characteristics of Ketamine-Associated Laryngospasm

Unpredictable Nature

Laryngospasm with ketamine appears to be idiosyncratic rather than dose-dependent or associated with specific patient factors 4. A case-control study of 8,282 ketamine sedations (including 22 laryngospasm cases) found:

• No statistical association with age, dose, oropharyngeal procedures, underlying physical illness, route of administration, or coadministered anticholinergics 4
• Coadministered benzodiazepines showed only a borderline association that was considered anomalous 4

Rare Case Reports

• One case report describes severe refractory laryngospasm occurring despite deep anesthesia with ketamine and neuromuscular blockade with succinylcholine, suggesting a possible idiosyncratic ketamine effect 5
• This represents an extremely unusual presentation, as laryngospasm typically occurs during light anesthesia 5

Comparative Safety Profile

Overall Adverse Event Context

When considering laryngospasm within ketamine's broader safety profile in adults 3:

• Emergence phenomena (dysphoric reactions) are the most common adverse events at 10-20% 3
• Pharyngeal reflexes are generally preserved 3
• Brief apnea around the time of injection is common but typically self-limited 3
• Significant cardiorespiratory adverse events are rare and typically do not affect outcomes 3

Drug Combination Effects

When propofol and ketamine are combined, the incidences of multiple adverse events (including agitation, apnea, hypoxia, bradycardia, hypotension, and vomiting) are lower compared to each medication separately 1. However, specific data on laryngospasm rates with combination therapy were not provided in the available evidence.

Clinical Implications and Preparedness

Essential Preparedness

Despite the rarity of laryngospasm, all clinicians administering ketamine must be prepared for its rapid identification and management 4. This includes:

• Having airway management equipment immediately available 3
• Capability to provide positive pressure ventilation 2
• Knowledge of laryngospasm management techniques 6

Knowledge Gaps Among Providers

A survey of pediatric hospitalists revealed that 95% could identify laryngospasm when it occurred, and 82-84% chose appropriate initial management strategies 6. However, as the clinical scenario deteriorated, only 66-71% selected optimal management approaches 6, highlighting the need for ongoing training in managing this rare complication.

Anticholinergic Prophylaxis

Given no evidence that anticholinergics decrease the risk of laryngospasm, their routine coadministration appears unnecessary 4. Their use should be based on other clinical indications (such as managing hypersalivation) rather than laryngospasm prevention.

Special Considerations

Aspiration Risk Context

The 2020 international consensus statement on fasting notes that aspiration has not been previously reported with ketamine monotherapy except in compromised neonates 2. This unique dissociative state helps maintain protective airway reflexes 2, which may contribute to the low laryngospasm rate despite preserved airway reflexes.

High-Risk Scenarios

While laryngospasm appears idiosyncratic in typical ED procedural sedation, clinicians should maintain heightened vigilance in:

• Patients with active upper airway pathology 7
• Procedures involving airway instrumentation 4
• Patients with increased upper airway secretions 7