Can ketamine be used as an induction of anesthesia in trauma patients with hemodynamic instability?

From the Guidelines

Ketamine is a suitable choice for anesthesia induction in trauma patients with hemodynamic instability, as it maintains or slightly increases blood pressure and heart rate through sympathetic stimulation. The recommended dose for induction is 1-2 mg/kg IV given slowly over 1-2 minutes, as suggested by the guidelines for safe transfer of the brain-injured patient 1. When using ketamine in trauma, consider combining it with a benzodiazepine (such as midazolam 1-2 mg IV) to reduce the risk of emergence reactions. Be aware that ketamine should be used cautiously in patients with severe hypertension or those with known or suspected increased intracranial pressure, though recent evidence suggests its safety even in traumatic brain injury has been underestimated 1. Ketamine's dissociative properties provide analgesia along with anesthesia, which is beneficial in painful traumatic injuries. The medication has minimal effects on respiratory drive and preserves airway reflexes better than other induction agents, offering an additional safety margin during the critical induction phase in trauma patients. Some studies have compared ketamine with other induction agents, such as etomidate, and found no significant difference in mortality or peri-intubation hemodynamics 1. However, the choice of induction agent should be individualized based on the patient's specific condition and the clinician's experience. Key benefits of ketamine include:

• Maintaining hemodynamic stability
• Providing analgesia and anesthesia
• Preserving airway reflexes and respiratory drive
• Being a suitable option for patients with traumatic brain injury. Overall, ketamine is a valuable option for anesthesia induction in trauma patients with hemodynamic instability, and its use should be considered on a case-by-case basis.

From the FDA Drug Label

Hemodynamic Instability: Monitor vital signs and cardiac function during ketamine hydrochloride administration. (5.1)

Ketamine can be used as an induction of anesthesia in trauma patients with hemodynamic instability, but monitoring of vital signs and cardiac function is required during administration 2. It is essential to be cautious and closely monitor the patient's condition due to the potential for hemodynamic instability. Ketamine hydrochloride injection should be administered by or under the direction of physicians experienced in the administration of general anesthetics, maintenance of a patent airway, and oxygenation and ventilation 2.

From the Research

Use of Ketamine in Trauma Patients

• Ketamine can be used as an induction of anesthesia in trauma patients with hemodynamic instability, as it has been shown to maintain or improve cardiovascular performance in severely ill patients 3, 4.
• The drug has been traditionally contra-indicated in the presence of brain injury, but its adverse effects on intracranial pressure or cerebral blood flow are attenuated or reversed by controlled ventilation, subsequent anesthesia, and the greater general hemodynamic stability conferred by the drug 3.
• Ketamine's strong analgesic effect at subanesthetic doses allows it to be used as an analgesic during postoperative intensive care or as an analgesic-plus-sedative for patients receiving mechanical ventilation 5.

Hemodynamic Effects of Ketamine

• Ketamine induction of general anesthesia exerts beneficial stimulatory effects on the cardiovascular system, with significant elevations in pulse rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure 4.
• The drug has an excellent hemodynamic profile, making it the agent of choice for patients with unstable hemodynamics, such as shocked or hypotensive patients 6.
• However, ketamine's clinical uses can cause significant cardiovascular stimulations that may be deleterious in patients with cardiovascular diseases 7, 4.

Safety and Efficacy of Ketamine

• Ketamine usage has been associated with a lower risk of respiratory depression and relatively more conserved airway reflexes 6.
• The drug produces bronchodilation, allowing for secure induction of anesthesia in patients with life-threatening asthma and intense acute bronchial constriction 6.
• However, various side effects along with no confirmatory data on long-term treatment demand great caution when using ketamine for treating complex chronic pains 6.