Can ketamine be used as a bronchodilator?

From the Guidelines

Ketamine can be used as a bronchodilator, though it's not a first-line treatment for this purpose. Ketamine has bronchodilatory properties that work by relaxing smooth muscle in the airways through multiple mechanisms, including NMDA receptor antagonism and sympathomimetic effects. It's most commonly considered in specific clinical scenarios such as status asthmaticus or severe bronchospasm that is unresponsive to conventional treatments. When used for bronchodilation, ketamine is typically administered intravenously at doses of 0.1-0.5 mg/kg as a bolus, followed by an infusion of 0.5-2 mg/kg/hour if needed. The bronchodilatory effects typically begin within minutes of administration. However, ketamine has important side effects to consider, including increased secretions, potential for hallucinations or emergence phenomena, tachycardia, and increased blood pressure. These effects limit its routine use as a bronchodilator. In clinical practice, ketamine is generally reserved for emergency situations when standard bronchodilators like beta-agonists, anticholinergics, and corticosteroids have failed to adequately control severe bronchospasm 1.

Key Points to Consider

• Ketamine is not a first-line treatment for bronchodilation due to its side effects and the availability of more effective and safer alternatives.
• The use of ketamine as a bronchodilator is typically reserved for severe cases of bronchospasm that are unresponsive to conventional treatments.
• The administration of ketamine for bronchodilation should be done with caution, considering its potential side effects and the need for close monitoring.
• Standard bronchodilators such as beta-agonists, anticholinergics, and corticosteroids should be used as the primary treatment for bronchospasm, with ketamine considered only when these treatments have failed.

Clinical Scenarios for Ketamine Use

• Status asthmaticus: Ketamine may be considered in cases of status asthmaticus that are unresponsive to conventional treatments.
• Severe bronchospasm: Ketamine may be used in cases of severe bronchospasm that are unresponsive to conventional treatments.
• Emergency situations: Ketamine may be considered in emergency situations where standard bronchodilators are not effective or available.

Important Considerations

• Side effects: Ketamine has important side effects to consider, including increased secretions, potential for hallucinations or emergence phenomena, tachycardia, and increased blood pressure.
• Monitoring: Close monitoring is necessary when using ketamine as a bronchodilator, due to its potential side effects.
• Alternative treatments: Standard bronchodilators such as beta-agonists, anticholinergics, and corticosteroids should be used as the primary treatment for bronchospasm, with ketamine considered only when these treatments have failed.

From the FDA Drug Label

Ketamine is a potent bronchodilator suitable for anesthetizing patients at high risk for bronchospasm. Ketamine can be used as a bronchodilator. It is suitable for anesthetizing patients at high risk for bronchospasm 2.

• Key points:
  • Ketamine has bronchodilatory effects
  • Suitable for patients at high risk for bronchospasm
  • Mechanism of action is primarily due to antagonism of N-methyl-D-aspartate (NMDA receptors) in the central nervous system, but its bronchodilatory effects make it useful in this context.

From the Research

Ketamine as a Bronchodilator

• Ketamine has been studied as a potential bronchodilator in various clinical settings, including acute asthma exacerbation and chronic obstructive pulmonary disease (COPD) 3, 4.
• The use of ketamine as a bronchodilator has been shown to improve respiratory parameters, such as peak expiratory flow and oxygen saturation, in pediatric patients with acute asthma exacerbation 3.
• Ketamine infusion has also been used to treat bronchospasm in critically ill patients, resulting in improved sedation, increased arterial pressure, and diminished bronchospasm 4.
• However, the effectiveness of ketamine as a bronchodilator compared to other bronchodilators, such as salmeterol and ipratropium bromide, is not well established 5, 6.
• The most common side effects of ketamine use as a bronchodilator include increased tracheobronchial secretions and hallucinations, which can be managed with discontinuation or additional medication 3.

Comparison with Other Bronchodilators

• Salmeterol has been shown to have a longer duration of action and superior bronchodilator efficacy compared to ipratropium bromide in patients with COPD 5.
• Intravenous salbutamol has been shown to improve outcome, including earlier discharge, in children with severe acute asthma, but the addition of ipratropium bromide provided no significant further benefit 6.
• Ketamine's unique mechanism of action, as an antagonist of the N-methyl-D-aspartate receptor, may provide an alternative option for patients who do not respond to standard bronchodilator therapy 7.

Clinical Use

• The use of ketamine as a bronchodilator should be considered in carefully selected cases and closely monitored for adverse events 3.
• Further research is needed to fully evaluate the effectiveness and long-term effects of ketamine as a bronchodilator in various clinical settings 3, 7.