By Peter Antevy, MD – Pre-hospital pain control is moving at a rapid pace; it’s time to buckle up for an interesting ride. While Morphine is being laid to rest by many EMS agencies due to its side effect profile, time to peak effect and the inability to be administered intranasally, other medications are moving to the forefront of care. Ask any field provider about morphine and you are not likely to get a positive response. A typical call requiring morphine administration results in a very slow effect (25 minute peak), often leaving the paramedic in a precarious position. Patients remain in absolute agony, as they are being moved and transported to the local hospital. Then right as the transfer of care occurs and the doctor walks in the room the patient finally starts feeling better….and then gives the doctor all the credit. It’s these types of failures that have led EMS agencies to look for a better alternative.

The past few years has seen Fentanyl take a more prominent role in pre-hospital pain control. After all, it is the perfect EMS drug for pain for the same reasons that Midazolam (Versed) is for seizures. Fentanyl and Midazolam both have a very short onset of action. Lipid soluble Fentanyl rapidly crosses the blood brain barrier and leads to rapid clinical benefit. The 2010 paper by Saunders and Adelgais concluded that an intranasal Fentanyl dose of 2 mcg/kg provided effective analgesia for pediatric ED patients with painful orthopedic trauma within 10 minutes of administration. Contrast this with Morphine, the least lipid soluble narcotic available, which peaks 25 minutes after administration. What’s nice about Fentanyl’s rapid onset is that the field provider can address their patient’s pain prior to transport and feel confident that the issue has been addressed appropriately. It’s a win-win scenario and the “fast-on, fast-off” property makes Fentanyl the perfect EMS narcotic.

Note the rapid peak to Fentanyl compared to Morphine

What are the downsides to Fentanyl? Perhaps more than any other narcotic, Fentanyl has a great potential for diversion. Many agencies that have experience with Fentanyl know this first hand and have taken extra precautions to prevent such activity. There is also the respiratory depression that comes along with Fentanyl. An inadvertent decimal point error and your patient (especially pediatric) will become apneic. Take for example a 1-year-old child with a femur fracture. This 10 kg child can receive a Fentanyl dose of 1 mcg/kg IV. That’s 10 mcg in total. What is the volume required for this dose? The drug comes packaged as 50 mcg/mL so the volume is 0.2 mL: a dose easily mistaken for 2 mL in a hurried scenario.  That’s how the phrase “death by decimal point” was coined. On the flip side is the under-dosing of the very same drug. When used via the MAD device the dead space eats up 0.1 mL of the total volume. So when the 1-year old patient requires 0.2 mL, the MAD device takes half and leaves the child with the equivalent of a homeopathic dose. Lastly, let’s not forget the risk of “chest wall rigidity syndrome“, thought mainly to be the result of rapid IV administration of Fentanyl. This anxiety-provoking clinical syndrome may be resistant to Naloxone while at the same time poorly responsive to BVM.  Succinylcholine may be the only answer, yet the field provider may not have access to this medication. Either way, it promises to be stressful irrespective of the provider’s level of airway experience.

While Fentanyl has left the station some time ago, another drug has emerged in adult care and is gaining rapid momentum. Ketamine Hydrochloride has become ‘all the rage’ among EM and retrieval physicians, so much so that one physician (Minh Le Cong) even made it his Twitter handle (@Ketaminh)….very clever! Ketamine has been used in the Pediatric Emergency Department safely, and frequently, for over a decade and a dose of 1 mg/kg slow IVP (at least one minute) is the go-to medication for most short, painful procedures in children. The benefits are clear and include maintenance of airway reflexes and no effect on respiratory rate, all while creating a rapid dissociative state. Furthermore, Ketamine is safely and easily administered IV, IM and IN (dosing recommendations differ based on route of administration).

The new question now is “can Ketamine be used for pre-hospital pain control in adult and pediatric patients?” The answer is clear. Dating back to the early 90’s, studies have repeatedly demonstrated the benefit and safety profile of this once feared drug. In 1997, Humphries et al described the superiority of oral Ketamine over Acetaminophen-codeine plus Diphenhydramine in pediatric burn patients. Ketamine has been extremely successful in treating chronic pain conditions such as Reflex Sympathetic Dystrophy (RSD) and Sickle Cell Disease, specifically in the pediatric population. A comprehensive review of Ketamine use in the pediatric emergency setting was published in 2004 (Emerj Med Journal – full article). It evaluated 97 case series’ which included a total of 11,589 cases of Ketamine use in children. Only 2 cases total required intubation, but interestingly even children receiving up to 100 times the intended dose suffered no adverse events. Laryngospasm was described as “very rare” and having occurred at a greater rate with instrumentation of the oropharynx or hypo-pharynx. Finally the review reported emergence phenomena occurring in up to 10% of cases. The incidence was lower with children under 10 years of age, doses of 2 mg/kg or less (2% incidence), and when Ketamine was provided intramuscularly.