Literature Review: Overdose Reversal and Refusal of Transport

Wampler DA, Molina DK, McManus J, et al. No deaths associated with patient refusal of transport after naloxone-reversed opioid overdose. Prehosp Emerg Care 15(3): 320–4, Jul–Sep 2011.

Abstract

Naloxone is widely used in the treatment and reversal of opioid overdose. Most emergency medical services (EMS) systems administer naloxone by standing order, and titrate only to reverse respiratory depression without fully reversing sedation. Some EMS systems routinely administer sufficient naloxone to fully reverse the effects of opioid overdose. Frequently patients refuse further medical evaluation or intervention, including transport. Objectives—The purpose of this study was to evaluate the safety of this practice and determine whether increased mortality is associated with full reversal of opioids. As a component of a comprehensive quality assurance initiative, we assessed mortality during the 48 hours after patients received naloxone to reverse opioid overdose followed by patient-initiated refusal of transportation. Methods—The setting was a large urban fire-based EMS system. Investigators provided the Bexar County [TX] Medical Examiner’s Office (MEO) with a list of patients who were treated by the San Antonio Fire Department with naloxone, and not transported. Inclusion criteria were administration of naloxone and patient-initiated refusal. Patient dispositions also included aid only, referral to the MEO, or referral to law enforcement. The list was then compared with the MEO database. A chart review was completed on all patients treated and subsequently presented to the MEO within two days. A secondary time period of 30 days was also assessed.

Results—The list identified 592 patients treated with naloxone and not transported to the emergency department. Five-hundred fifty-two patients received naloxone and refused transport or were not transported. The remaining 40 patients all presented to EMS in cardiac arrest, [received naloxone] during the course of resuscitation, and [had subsequent resuscitative efforts] terminated in the field. None of the patients receiving naloxone with a subsequent patient-initiated refusal were examined at the MEO within the two-day end point. The 30-day assessment revealed that nine individuals were treated with naloxone and subsequently died, but the shortest time interval between date of service and date of death was four days. Conclusion—The primary outcome was that no patients who were treated with naloxone for opioid overdose and then refused care were examined by the MEO within a 48-hour time frame.

Comment

EMS treatment protocols typically require that all patients with opioid overdoses treated with naloxone be transported for observation and retreatment if needed. The most serious concern is that since the half-life of naloxone is shorter than the opioid’s, respiratory depression may recur once the naloxone effect goes away. The San Antonio Fire protocol is to give a relatively large dose of naloxone: 2 mg IM, followed by 2 mg IV and later, with patient consent, an additional 2 mg IM. At that dose, even with its shorter half-life, naloxone’s physiological effects seemed to last long enough to protect the patients in this study population. This is consistent with previous reports on opioid overdose patients from San Diego and San Francisco.

Opioid overdoses can also cause non-cardiac pulmonary edema (NCPE), an unusual but not rare complication due to an increased pulmonary capillary permeability that can cause hypoxia and death. NCPE typically occurs soon after the event and resolves within 24 hours, so by looking at deaths at 48 hours and 30 days, any that could have been due to NCPE should have been found.

We still do not have enough information to know which (if any) patients with what type of opioid (e.g., heroin, methadone, morphine), time, dose and method of administration can be safely treated and not transported. More research is needed before recommending any change in treatment protocols. It is reassuring, though, to know that opioid OD patients who refuse transportation after receiving naloxone seem, in the short term at least, unlikely to have lethal complication.

Angelo Salvucci, Jr., MD, FACEP, is medical director for the Santa Barbara County and Ventura County (CA) EMS agencies and a member of EMS World's editorial advisory board.