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2016/12/11 - Medical Tidbits: Medication Assisted Intubation

In this month’s medical tidbit …


When dealing with intubations there are many “Terms” used that include RSI (rapid sequence intubation or resuscitation sequence intubation) / DSI (delayed sequence intubation) / MAI (medication assisted intubation).   Of these terms the one the seems to fit best (or at least encompasses the other terms) with the retrieval medicine concept is the medication assisted intubation.   So much of what we do in the pre-hospital and interfacility transport depends on a number of extenuating circumstances that cannot be predicted before we are able to intubate the patient.  This can include current medical problems / abnormal lab values / EKG changes / co-morbidities, etc. 


As we perform the process of medication assisted intubation and take into account all of the potential factors along with assessing the patient for the potential of difficulty with ventilating (not bagging --- thanks Eric) and intubating (looking at the LEMON law) we have to determine which of the sedation medications will be best.  


In the new guidelines the process has been streamlined to think of the number “3”.   Ketamine dose is now 3 mg / kg, etomidate is 0.3 mg / kg, fentanyl induction dose is 3 mcg / kg with versed induction dose of 0.3 mg / kg.   This will help take out some of the guessing game at 3 o’clock in the morning in the back of an ambulance with the temperature of 28 degrees outside and ensure that we are properly sedating the patient before intubation. (new guidelines coming out will reflect this change)


see NWOEMS guidelines



As explained in the guidelines the whole intention of performing medication assisted intubation is to ensure that we are successful at first pass intubations.   There are a number of situations where this is critical and a single hypoxic event can be catastrophic for the patient (TBI and stroke patients are the main ones).   In conversation with Dr Case and several other critical care physicians their belief is that a paralytic agent for these types of patients is essential to ensure the first pass intubation.   So the devil is in the details with this process --- sedating the patient and then visualizing with the laryngoscope can cause patients to have laryngospasms which in turn will cause the hypoxic event … can give additional sedation to help with the laryngospasms or paralyze the patient.   There are times (obese patients) that paralyzing the patient we think might be unrealistic, but that is usually the best thing to ensure the first pass success.


So which medication do we choose .. and do we actually need additional sedation medications?   (1) of the key quality improvement measures that we have been looking at is the addition of pain medication for the paralyzed trauma patient.    All would agree that we should ensure that these patients receive some form of pain medication.   the truth is that is not always the case.  So when looking at our sedation medications ketamine has risen to the top because of its pain medication properties along with being an excellent induction agent for intubation.   Rapid onset along with a cardioprotective profile (increase in heart rate and blood pressure) makes it an ideal candidate for so many of our intubation types.   The increased heart rate of course is ketamine’s downfall for patients with rapid heart rate (adults w/ HR > 140) that need to be intubation that are also hypotensive.   Of course if you talk to some of the neurosurgeons and anesthesiologist they will tell you that ketamine is a BAD drug in the TBI patient because it will cause an increase in ICP.  Yes all of the studies out there indicate that this is a transient phenomenon with no long term sequela and the benefit of reduction is the risk of hypotension (which has been shown to increase morbidity) pushes ketamine to the top.   Coming into a close second remains our tried and true sedation medication etomidate.  The dose is the 0.3 mg / kg (in line with the rules of 3 for sedation).    Etomidate like ketamine has the cardiovascular protective properties with very little side effects.  The important feature of etomidate that is not helpful is the aspect that etomidate does not have any pain relieving properties.   So we as retrievalist have to remember to give some fentanyl to the paralyzed / intubated patient.   Fentanyl and versed as induction agents are part of the guidelines as a sort of last resort .. we have to other medications to give and need to intubate someone.   The major downside to using these agents in the time consideration (which leads us back to the notion of MAI versus RSI).   In order to get good quality sedation for these medications we have to use very large doses and allow for the medications to work.   This process can take minutes to work (not a rapid process) and the patient might truly ever be sedated.


In the end … first pass success is the key … first pass success is the key … first pass success is the key.   How do we get there … choose the proper sedation medication and if necessary have an additional medication ready.   Paralyze the patient (specially some of the patients that we would be concerned about paralyzing) … this will help facilitate the intubation process.   Have all of the potential adjunct intubation equipment available and do not forget to ensure pain medication was given when we use sedation only medications.


Until next month … remember what you do really does matter … share the care; work as a team