Prehospital Pain Management

Michelle Welsford

Greg Soto

Introduction

When it comes to managing acute pain emergency prehospital practitioners, similar to emergency department (ED) personnel, are often falling short.
Inadequate analgesia, referred to as oligoanalgesia, remains a major problem in both prehospital and Emergency Department (ED) care.
Inadequate pain control takes several forms:
- Delayed or nonreceipt of analgesia
- Use of ineffective analgesia (e.g., non-steroidal anti-inflammatory drugs (NSAIDs) where opioids are indicated)
- Underdosing analgesics
- Failure to combine analgesics
- Failure to use adjuncts
Two important reasons not to delay analgesia in the field are as follow:
- Analgesia administration is associated with decreased need for subsequent opioids.
- If analgesia is delayed until ED arrival, time to administration can be significantly delayed (up to 2 hours in one study).
Pain is associated with increased morbidity:
- Increased patient suffering from the unpleasant experience.
- Can lead to delayed wound healing.
- Increased metabolic rate.
- Altered immune response.
- Lowered pain threshold for subsequent painful experiences.
- Increased association with PTSD.
The goal of prehospital pain management is to start the pain relief (not necessarily eliminate) – without significant complications.
Several important emergency medical service (EMS) advocacy groups have called for improvements in prehospital pain management.
- The National Association of EMS Physicians, the American College of Emergency Physicians, and the EMS Outcomes Project have all advocated for this.

Reasons for Oligoanalgesia

Reasons cited for inadequate pain management in the out-of-hospital setting include:
- Poor understanding of pain
- Underestimation of pain
- Poor assessment (poor understanding of available pain assessment tools)
- Provider biases – barriers such as sex, age, race, ethnicity, language, and socioeconomic status
- Fears related to opioid dependence and drug-seeking behavior
- Poor choice of analgesic
- Inadequate protocols
- Online medical control physician attitudes and practices
  - Concern of on scene delay

Pain Assessment Tools

Patients may not receive analgesia if they are not questioned regarding their pain.
Emergency providers often underestimate a patient’s analgesic requirements.
- Have also been found to discredit patients’ pain based on their own beliefs.
Pain should be assessed and reassessed to ensure appropriate treatment.
There are multitudes of pain scales tested and used in hospitals but pain scales used prehospital need to be simple, quick, and reliable.
The verbal rating scale (VRS) and numerical rating scale (NRS) have both been validated in the ED for adults and have been shown to be easy, quick, discriminating, and reliable.
- The NRS is likely the most commonly used tool for pain assessment and reporting in prehospital care because it does not require any equipment or charts.
- Provider verbally asks the patient to rate their pain on a scale of 0–10.
For children, there are several scales including the pictorial Faces Pain Scale, and for younger children observational/behavioral scales can be used (see Chapters 13 and 22).

Patient Monitoring for Analgesia Administration

In addition to assessing the patient’s perception of pain, it is important for prehospital providers to undertake a full assessment.
- This includes:
  - Vital signs prior to analgesia administration (blood pressure, heart rate, respiratory rate, SpO₂, and ECG rhythm).
  - Continually reassess the patient’s pain scores.
  - Repeat vital signs periodically following analgesia administration.
It has been established that prehospital providers do not consistently document pain encountered in the field.
It is important to document:
- Initial pain score – identifies need for analgesia.
- Response to initial treatment.
- Ongoing need for further treatment.
Knowledge of the side effects of the specific agents will also guide the reassessments so that these can be recognized early and managed (e.g., respiratory depression, hypotension, or nausea and vomiting with opioids).

Contraindications and Cautions for Analgesia Administration

There are several relative contraindications to administration of analgesics in the field:
- Hypotension
- Hemodynamic instability
- Allergies
- Comorbidities that can lead to complications with specific agents (e.g., renal failure and NSAIDs)
Extra caution with above contraindications is necessary in the prehospital setting since there is:
- Less availability of backup
- Fewer reversal agents available
- Fewer agents to counteract complications
There are also some medical conditions that are best treated with other therapies rather than only analgesics.
- For example, ongoing cardiac ischemia where treating with analgesics alone may prevent administration of other more suitable medications.