Drug Profile: Ketamine

Ketamine 

By Adam Thompson, EMT-P

Since my beginning in the world of prehospital medicine, which wasn't too long ago, I have heard more and more about a particular drug.  I have attended critical care and emergency medicine conferences and the same has been true.  Ketamine seems to have become a favorite amongst many physicians.  I have never administered the drug myself, but it has made its way into some prehospital standing orders, and with reason.  

Ketamine Hydrochloride

Non-barbiturate anesthetic 

Mechanism of action:

• Creates a state of dissociation from reality.  
• Catecholamines (epinephrine & norepinephrine) are released.  
• Spinal reflexes are reduced.

Indications:

• Indicated for anesthesia when cardiovascular depression must be avoided.  
• A commonly used induction agent to facilitate endotracheal intubation.

Contraindications:

• Hypersensitivity to Ketamine
• Increased intracranial pressure
• Hypertension
• Aneurysm
• Thyrotoxicosis (hyperthyroid)
• Congestive heart failure
• Angina
• Psychotic disorders
• Pregnancy

So there are a lot of contraindications that happen to be conditions that we see commonly.  But think about what they are, and what the side effects are of the other drugs that we administer for similar indications.  Almost every other medication decreases blood pressure.  Ketamine actually increases it, so it has its place.  

Side Effects:

• Hallucinations
• Vivid dreams
• Hypertension
• Increased cardiac output
• Tachycardia
• Paradoxical direct myocardial depression
• Increased ICP
• Tonic-clonic movements

Overdose:

      With high doses or rapid administration, respiratory depression may occur.

Dosage:

• Oral: Pediatric 6 - 10 mg/kg
• Intramuscular: 3 - 8 mg/kg
• Intravenous: Pediatric 0.5 - 2 mg/kg, Adult 1 - 4.5 mg/kg

Onset is about 1-2 minutes if given I.V., and 3-8 minutes if given I.M.

Some research:

The effect of combined treatment with morphine sulphate and low-dose ketamine in a prehospital setting [1] 

Conclusion 

We conclude that morphine sulphate with addition of small doses of ketamine provide adequate pain relief in patients with bone fractures, with an increase in systolic blood pressure, but without significant side effects.

Anesthesia in prehospital emergencies and in the emergency department. [2]

Abstract

PURPOSE OF REVIEW: Recently, notable progress has been made in the field of anesthesia drugs and airway management. RECENT FINDINGS: Anesthesia in prehospital emergencies and in the emergency department is reviewed and guidelines are discussed. SUMMARY: Preoxygenation should be performed with high-flow oxygen delivered through a tight-fitting face mask with a reservoir. Ketamine may be the induction agent of choice in hemodynamically unstable patients. The rocuronium antagonist sugammadex may have the potential to make rocuronium a first-line neuromuscular blocking agent in emergency induction. Experienced healthcare providers may consider prehospital anesthesia induction. Moderately experienced healthcare providers should optimize oxygenation, hasten hospital transfer and only try to intubate a patient whose life is threatened. When intubation fails twice, ventilation should be performed with an alternative supraglottic airway or a bag-valve-mask device. Lesser experienced healthcare providers should completely refrain from intubation, optimize oxygenation, hasten hospital transfer and ventilate patients only in life-threatening circumstances with a supraglottic airway or a bag-valve-mask device. Senior help should be sought early. In a 'cannot ventilate-cannot intubate' situation, a supraglottic airway should be employed and, if ventilation is still unsuccessful, a surgical airway should be performed. Capnography should be used in every ventilated patient. Clinical practice is essential to retain anesthesia and airway management skills.

Pre-hospital use of ketamine for analgesia and procedural sedation [3]

Abstract

The safe delivery of adequate analgesia and appropriate sedation is a priority in prehospital care. The use of ketamine is described for analgesia and sedation in 1030 trauma patients in a physician-led prehospital trauma service. Ketamine was mainly used in awake non-trapped patients with blunt trauma for procedural sedation and analgesia. Detailed database searches did not demonstrate loss of airway, oxygen desaturation or clinically significant emergence reactions after ketamine administration. Ketamine is relatively safe when used by physicians in prehospital trauma care.

Ketamine for prehospital use: new look at an old drug. [4]

Abstract

INTRODUCTION: Ketamine has been used extensively for analgesia and anesthesia in many situations, including disaster surgery where extra personnel and advanced monitoring are not available. There are many features of ketamine that seem to make it an ideal drug for prehospital use. The reported use of ketamine in the prehospital environment is limited, however. The purpose of this study is to review the experience in the use of ketamine in a regional air ambulance service and suggest indications for its use in the prehospital setting. METHODS: This was a retrospective study of all patients transported by a regional aeromedical program. Patients were included in this study if the crew had used ketamine at any time during the flight. Data regarding the transport collected included patient age, type of transport, indications for ketamine use, and adverse reactions. RESULTS: During the period studied, ketamine was used in 40 patients. The age range was 2 months to 75 years. The indications and situations requiring use were varied and included both trauma and medical patients. Hypotension with need for analgesia, agitation or combativeness and intact airway, or pain unresponsive to narcotic medications were the most common indications for use. Ketamine was used both intravenous and intramuscular, even without intravenous access. There were no adverse reactions. CONCLUSIONS: Ketamine is an ideal drug for use in many prehospital situations. Our experience suggests that it is safe, effective, and may be more appropriate than drugs currently used by prehospital providers.