Case summary:

An ALS crew was dispatched to a middle-aged woman with concern for an overdose.  The patient’s husband reported he had just arrived home from the grocery store and found the patient unresponsive and does report that the patient has a history of opioid use disorder.  The crew assessed the patient and found her to be unresponsive, apneic and with a weak radial pulse.  The crew immediately started BVM ventilation with 100% O2.  The crew noted the patient had pinpoint pupils.  While the patient was being bagged, an IV was placed and 2mg of IV naloxone was administered.  The crew then obtained a full set of vitals and noted that the patient started breathing on her own but was hypoventilating so they continued support with BVM

Vitals: BP 168/99,  HR 81,  RR 6,  Sat 84% NRB,  glucose 304

And additional 2mg of IV Narcan was administered 4 minutes after the first dose given she was still hypoventilating.  Shortly after this dose, the patients respiration rate normalized but she remained unconscious.  The patient was extricated to the ambulance and reassessed with her new vitals as follows.

Vitals: BP 142/99,  HR 109,  RR 16,  Sat 99% on O2,  ETCO2 33

While in route, the patient became more alert and eventually was oriented x4.  She did admit to taking an unknown pill.  She was assessed for trauma and none was identified.  Crew arrived at the hospital and her care was handed off.

While this is a common scenario, the crew handled it perfectly and this highlights some important aspects of opioid overdose care that we will discuss below.

Highlights of the case:

Priority in opioid overdose is BVM

Opioids function by stimulating the mu opioid receptor in the brain which causes pain relief, but also decreases a patient’s respiratory drive due to its effect on the brain stem.  This leads to hypoventilation which in turn leads to elevated CO2 levels.  It is the elevated CO2 level that causes the patient to become unconscious, not the opioid itself.  For naloxone to wake a patient up, it needs to be administered, absorbed, circulate through the blood stream, cross into the brain, block the opioid from binding to the brain stem, then the patient needs to increase his/her respiratory rate and blow off enough CO2 to wake up.  This takes time and while we are waiting for this all to take place, the patient can become more hypoxic and arrest.  Alternatively, we can immediately initiate BVM ventilation and reverse both the hypoxia and hypercapnia.  You can wake a patient up from an opioid overdose without giving any naloxone simply by bagging them down to a normal CO2 level.  Once you have initiated BVM ventilation, then you can work on treating with naloxone.  This crew prioritized BVM over all other care for a hypoventilating patient.  Once they were managing the airway and breathing, then they focused on getting naloxone on board.

IV naloxone is often faster than IN naloxone

It is important to know how long it takes naloxone to work since we do not want to give an additional dose until we have allowed the first dose to work.  Giving too much naloxone increases the risk of opioid withdrawal which is miserable for patients.  Giving too much naloxone also increases the risk of non-cardiogenic pulmonary edema as well.  The onset of naloxone based on its route of administration is as follows:

·         IV: ~2m

·         IM: 2-5m

·         IN: 8-13m

As you can see, IN naloxone takes quite a while to begin to function.  If you are trained to place an IV, it is often faster to get naloxone to begin functioning in the brain by placing an IV and administering it via that IV than to immediately administer it intranasally. 

The goal of naloxone is to treat hypoventilation from opioid use, not wake the patient up.

The indication for naloxone is to treat hypoventilation in the setting of suspected opioid overdose.  If a patient is ventilating normally but is unconscious, naloxone is not indicated.  This is true even if you are 100% sure the patient used an opioid.  In these situations, we should place the patient on ETCO2 and monitor ventilations during transport.  If the patients respiratory rate dips below 10 or the patient’s ETCO2 rises above 45, give the smallest dose of naloxone possible to improve the ventilation to a normal range.  This would ideally be via an IV since it has the quickest onset and is therefore the easiest to titrate.  This is exactly how this crw handled their patient.  They gave just enough IV naloxone to normalize the ventilation and then monitored the patient using ETCO2.  The patient woke up on her own after she blew off enough CO2.