5 things EMS providers need to know about opioid overdose and respiratory compromise

Timely recognition, airway management, administration of naloxone (Narcan), and continuous assessment of oxygenation and ventilation can be lifesaving for patients who overdose on opioids. Here are five things every EMT and paramedic needs to know about caring for patients who overdose on opioids:

1. Opioids cause respiratory compromise and naloxone can reverse it

Opioid overdose is the leading cause of death among people from 25 to 60 years of age, accounting for more deaths than motor vehicle collisions, and has been declared a public health crisis [1]. Opioids are substances that include illicit drugs (most notably heroin), and prescribed medications (including hydrocodone, oxycodone, morphine, fentanyl and methadone).

All opioids stimulate specific receptors in the brain, which decreases perception of pain and causes a feeling of euphoria. When overstimulated, opioid receptors desensitize the brainstem to rises in CO2, which causes respiratory depression, loss of protective airway reflexes and respiratory arrest. Cardiac arrest from opioid overdoses is usually secondary to respiratory arrest.

Naloxone reverses narcotic overdoses by binding to opioid receptors, which blocks stimulation from the opioid substance. If administered in time, this restores the patient’s airway reflexes, respiratory drive and level of consciousness. Because of the time-sensitive importance of administering naloxone, the rise in opioid-related deaths has prompted wider distribution of naloxone for bystanders and first responders to administer.

The major drawback of naloxone is that it can trigger withdrawal symptoms in patients addicted to narcotics, including agitation, tachycardia, vomiting and pulmonary edema. Withdrawal symptoms are usually mild and short lasting, but some patients can become violent after receiving naloxone. Violent reactions are usually after intravenous naloxone is administered at too high a dose or too quickly [2]. Remember the goal of treatment is to restore respiratory drive and airway reflexes, prevent respiratory and cardiac arrest, and avoid causing severe opioid withdrawal [1].

2. Address circulation and ventilation before administering naloxone

Initial care for patients with a suspected narcotic overdose is the same as for any other patient with decreased mental status. They may present drowsy, even falling asleep mid-sentence, and require frequent verbal or tactile stimuli for arousal. They may also be unconscious with slow or agonal respirations, diaphoretic and cyanotic. Opioid usage also causes pupils to constrict, but coingestion of another substance or anoxic brain injury may cause pupils to dilate. Once respiratory depression occurs, assisted ventilation and naloxone are vital to prevent permanent brain damage or death [2].

First check the pulse of an unconscious patient. If a pulse is not detected start chest compressions and attach the defibrillator. The 2015 American Heart Association guidelines recommend standard ACLS practices for cardiac arrest secondary to opioid overdose, and makes no recommendation regarding the administration of naloxone [1]. Follow local protocols regarding if or when to administer naloxone to a patient in cardiac arrest.

For unconscious patients with a pulse, open the airway, assess respiratory rate and assist ventilation with a bag-valve mask. Consider placing an oral or nasal adjunct, but remove it before giving naloxone to prevent gagging after the patient is aroused.

Assess waveform capnography and pulse-oximetry to guide ventilation rate and to determine if ventilations are effective. Waveform capnography provides real-time feedback on respiratory rate, and amount of carbon dioxide (CO2) in exhaled air at the end of each breath (end-tidal CO2, or ETCO2). Use this feedback to monitor airway patency, circulation and how fast to assist ventilation. ETCO2 can be measured using nasal prongs or an adaptor between the mask and bag. If the airway is open and there is adequate mask seal, a rectangular waveform will appear after each assisted breath when air is exchanged in the lungs.

ETCO2 is normally between 35 and 45 mm Hg, but it is common for ETCO2 to be high, perhaps over 100 mm Hg, when their ventilation is first assisted. Use capnography as a guide to ventilate patients at 10-12 breaths/minute, and allow their ETCO2 to gradually return to normal. It is important to avoid ventilating patients too quickly, as this can decrease blood flow to the brain and reduce cardiac output.

Patients who overdose on opioids may also be bradycardic and hypotensive, and detection of a pulse can be difficult. Waveform capnography can help determine when patients have spontaneous circulation and when chest compressions are needed. A patient must have some circulation if a capnography waveform appears with ventilation, even if a pulse cannot be detected, and the AHA recommends that naloxone be administered in these circumstances [1].

For patients who are breathing adequately after opioid ingestion, the risk of withdrawal symptoms from naloxone outweighs any benefit from giving it. Waveform capnography and pulse-oximetry should also be used to monitor patients who are conscious but drowsy to detect deterioration. A decrease in respiratory rate and period of apnea can be immediately detected with the loss of a waveform, and a drop in pulse-oximetry indicates that the patient is not inhaling deeply enough for adequate oxygenation. Patients often breathe spontaneously with verbal or tactile stimuli, and naloxone should be given to patients who do not respond or require frequent arousal.

3. When giving naloxone, think intranasal administration first

Naloxone can be administered intravenously (IV), intramuscularly (IM), intranasally (IN), subcutaneous (SQ), endotracheal and via nebulizer. The most common routes for EMS administration are intranasal, intramuscular and intravenous, which has several advantages over the other routes for the initial dose.

Route, dose, and pharmacokinetics of Naloxone [2]:

Using a nasal atomizer, a standard dose of naloxone can be assembled and administered in less time than it takes to obtain intravenous access. Given the high prevalence of hepatitis C and HIV among intravenous opioid abusers, intranasal naloxone administration does not carry the risk of an accidental needlestick that comes with giving it intravenously or intramuscularly. Patients respond approximately 80 percent of the time to both intravenous and intranasal naloxone, but the onset of intranasal naloxone is longer, the recovery is more gradual, and there is less risk of patient agitation and withdrawal symptoms.

Because ventilation and oxygenation should be addressed before naloxone administration, other benefits of intranasal administration outweigh the added time needed to restore spontaneous respiration and airway reflexes. A higher dose of naloxone may be needed to reverse longer-lasting oral or transdermal opioids than for heroin. Even if a second intravenous dose is needed later, there is no downside to giving an initial dose intranasal before attempting intravenous access.

4. Use capnography to assess response to naloxone

It is easy to lose track of time while caring for a patient who is not breathing effectively and the decision about when to administer subsequent doses of naloxone can be difficult. Waveform capnography detects spontaneous respirations and normalization of ETCO2 indicates that the patient’s ventilation is improving. These signs may be seen before a visible chest rise or change in responsiveness, and are an indication to hold off on subsequent doses of naloxone and avoid the risk of withdrawal symptoms.

Approximately 20 percent of opioid overdose patients do not respond to naloxone. This may be from a high opioid dose, brain damage after a prolonged downtime, or use of other medications. When this occurs, continue to assist ventilation, consider placing an advanced airway device before moving the patient, and use capnography to guide ventilation rate and airway placement.

5. Additional assessment and transport considerations

For patients who respond to naloxone, monitor for return of respiratory depression. Attempt to determine what was ingested, ingestion time, amount taken (look at pill bottles or ask about bags of heroin), and if any other substances were ingested.

The decision about whether opioid overdose patients who respond to naloxone should be transported to the hospital is controversial. If allowed by protocol, a thorough assessment should be done on a patient who wishes to refuse transport after receiving naloxone, including pulse-oximetry and capnography, to document their ventilation and oxygen status before ending patient contact.

Longer acting oral and transdermal opioids can outlast naloxone, and a repeated naloxone dose may be needed 20-60 minutes after initial administration [2]. Use continuous waveform capnography and pulse-oximetry to identify when more naloxone is needed.

Use pulse-oximetry to determine if and how much oxygen should be administered. It should be titrated to maintain a pulse-ox reading of 92 percent, but not higher, as excessive oxygen may cause tissue damage from reperfusion injury.

Care for opioid overdoses requires more than just naloxone administration. Applying waveform capnography and pulse-oximetry helps determine when naloxone is needed for an opioid overdose, whether airway management is effective, and when a patient’s condition changes after naloxone administration.

Read next: How to treat sudden cardiac arrest, opioid overdose

References:

1. Lavonas EJ, Drennan IR, Gabrielli A, Heffner AC, Hoyte CO, Orkin AM, Sawyer KN, Donnino MW. Part 10: special circumstances of resuscitation: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Cardiovascular Care. Circulation. 2015;132(suppl 2):S501–S518.

2. McEvoy, M. Naloxone: Drug Whys. EMS1. 2015, October 22.

This article was originally posted Jan. 8, 2016. It has been updated.