A World of Hurt

Joan, a 60-year-old female, is supine on the floor, with her right hip supported by a pillow. "I broke my hip," she says calmly. "As long as I don't try to move it doesn't hurt." She tells you she tripped on an area rug in her kitchen and landed directly on her right hip. She reports pain and tenderness to palpation and has normal distal sensation and circulation. As we discuss options to minimize her pain during movement, I think about how pain signals are transmitted from the injury area to the brain and wonder how we can accurately assess Joan's pain.

Pain is the leading emergency medicine complaint, and its underlying causes are often of secondary concern to the patient.¹ Patients expect EMS to acknowledge their pain, assess it and treat it. The first step in improving assessment and treatment is to understand the pathophysiology and assessment of pain.²

WHAT IS PAIN?
The desire for pain relief often supercedes a patient's desire to identify and resolve the cause of pain. A position paper by the National Association of EMS Physicians says, "The NAEMSP believes that the relief of pain and suffering of patients must be a priority for every emergency medical services system."³

Understanding the underlying process or pathophysiology increases the likelihood an EMT will act on that knowledge. It is easy to say "give aspirin to any adult patient with chest pain"; however, understanding the cause of pain, like ischemic cardiac tissue; knowing how to assess the pain and differentiate it from among other potential causes, such as cardiac chest pain/pressure vs. respiratory tightness and shortness of breath; and understanding that aspirin inhibits platelet aggregation leads to faster and more effective treatment.

Pain is defined by the patient, not the caregiver. The International Association for the Study of Pain states that pain is "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage."⁴

Pain is a protective mechanism whenever body tissue is damaged. The pain stimulus triggers a cascade of emotional, physical and sensory reactions to communicate and lessen the pain.²

There is no predictable relationship between tissue damage and pain. Patients often report pain significantly higher or lower than what we might expect based on observable damage.⁵ Pain is a personal experience. Two patients with an identical injury or illness may have very different pain response and tolerance.

According to the American Pain Society, "Low back pain, arthritis and migraine headache alone account for pain in tens of millions of Americans."⁴ Annually, 25 million Americans have acute pain from injury or surgery, and 50 million suffer from chronic pain.⁴ Chronic pain is the most common cause of long-term disability, and symptoms often persist for years.

RESPONDING TO PAIN
For many patients, the impact and costs of pain, especially traumatic pain, begin with prehospital pain assessment and treatment. Research has documented that prehospital personnel can fail to recognize and properly treat pain.²

Most prehospital pain is nociceptive. Nociception includes four steps: transduction, transmission, perception and modulation.⁴ Transduction is the conversion of energy in a pain receptor from a noxious stimulus into a nerve impulse.^2,4,5 Pain receptors are arranged on free nerve endings in the superficial layers of the skin and walls of internal organ tissues. They are activated by chemical, mechanical or thermal noxious stimuli. For example, a nail through the foot is a noxious mechanical stimulus that causes damage to the skin and muscle tissues. Damaged foot tissue releases sensitizing substances that activate nociceptors. An action potential is created at the nociceptor, initiating an electrical charge that sends a nerve impulse to the brain.⁵

During transduction, the chemicals that stimulate the nerve impulse also begin the process of inflammation and repair of damaged tissue.² Inflammation leads to the swelling, redness and warmth we associate with an injury.

Transmission is movement of the nerve impulse generated by transduction to the spinal cord and brain.⁴ The signal is first transmitted by peripheral nerves to the spinal cord and then to brain structures that perceive pain.

There are two types of nociceptive transmission: fast warning, or fast pain, and slow warning, or slow pain.² Fast warning is a near instantaneous spinal reflex that pulls the body away from the pain stimulus. For example, when a child touches a hot stove, part of the transmission is reflexively interpreted at the spinal cord and an immediate fast warning is sent to pull away before the brain receives and processes the slow warning signal.^2,6 After the reflexive fast warning, the slow warning is still transmitted to the brain for processing. Slow warnings initiate emotional response, create pain memories, and begin sending signals to minimize pain transmission.²

Perception is becoming pain conscious. Pain is processed in several brain structures, each of which controls a different type of response. For example, one structure warns us to remove the noxious stimulus, another structure communicates the location and characteristics of the pain, and a third determines an emotional response.⁵ The intensity of pain perception often is related to the severity or rate of tissue destruction.²

Pain perception has multiple manifestations: behavioral, sensory and emotional.³ Modulation inhibits nociceptive impulses. Once pain is perceived, the brain releases substances that interfere with transmission of pain impulses, blocking the pathway for signal transmission to the brain.⁵ This is a remarkable compensation mechanism. The brain acknowledges pain, but acts quickly to block transmission of pain impulses so it can process other information and direct recovery behaviors and processes.

An immediate chemical reaction from a pain stimulus releases endorphins and enkephalins.² These are the natural equivalents to pain medication and bind with the same receptors that opioids like morphine bind with to reduce or mask pain. These natural pain relievers usually wear off in 20 to 30 minutes.²

ASSESSING PAIN
The Joint Commission on Accreditation of Healthcare Organizations has identified effective pain management as a priority.¹ Although JCAHO standards directly influence hospital-based ambulance services, these core principles of pain assessment are applicable to patient care in any context:⁴

• Assess all patients for pain.
• Patients have the right to pain assessment and management.
• Pain is always subjective.
• Physiological and behavioral signs of pain (e.g., tachycardia, grimacing) are neither sensitive nor specific.
• Use patient-appropriate assessment tools.
• Give special consideration to patients with difficulty communicating.
• Pain can exist with no evident cause.
• A uniform pain threshold does not exist.
• Different patients experience different levels of pain in response to comparable stimuli. Patients with chronic pain may be more sensitive.
• Unrelieved pain has adverse physical and psychological consequences.
• Pain is an unpleasant sensory and emotional experience.

Patient self-reporting is the most reliable indicator of the existence and intensity of pain.³ Accept and respect a self-report, unless there are obvious reasons for doubt.^4,5 Pain perception is most influenced by the patient's own previous experience, not your previous experience seeing similar injuries, wounds or illness.³ Pain cannot be judged by the amount of tissue damage, skeletal deformity or vital signs changes.

Start your pain assessment by reassuring the patient that you are identifying and treating the source of his pain. Patients might be reluctant to report pain due to low expectations of relief, fear of addiction to pain medications, dislike of medication side effects and not wanting a needlestick.⁴ Reassure them that the temporary discomfort of an IV or IM needle should lead to significant reduction of their primary pain.

Pain assessment and treatment also vary significantly between demographic groups. Those differences can be attributed to acceptability of pain expression based on age, cultural and gender norms, and EMT inferences about what is painful and what is not.

Some cultures encourage pain expression, others discourage it.² One study of the adequacy of analgesia in urban emergency departments produced some disturbing results.⁴ Hispanic patients with long-bone fractures were half as likely as non-Hispanic white patients to receive pain medication. Another study found black patients with isolated long-bone fractures were less likely to receive adequate analgesia when compared to white patients with similar injuries.²

Gender stereotypes also shape pain expressions. A male snowmobile rider broke his arm. It was severely angulated and CSM was impaired. In front of his companions, the patient was stoic and rated his pain very low--2 of 10. Once inside the privacy of the ambulance, however, his eyes filled with tears, and he reported a higher pain rating.

We can assist patients in communicating their pain perception with a pain assessment tool that identifies its presence, describes its intensity and questions changes over time and after treatment.

Many EMTs find the OPQRST mnemonic a useful memory device to learn about a patient's pain and to determine if it is somatic or visceral, but do not limit yourself to just six questions. Each letter is the start of a conversation:⁷

• Onset: Did your pain start suddenly, or did it gradually get worse? What were you doing when the pain started? Somatic pain is more likely to start suddenly.
• Provokes/Palliates: Is there anything that makes your pain better or worse? Movement worsens somatic pain; anxiety and exertion worsen visceral pain.⁷
• Quality: How would you describe your pain? Use an open-ended question without giving choices. If you ask, "Is the pain sharp or dull?" you limit the patient's response, when neither may be applicable.⁷ Somatic pain is more likely to be sharp and stabbing; visceral pain is more likely to be an ache or pressure.
• Radiates: Where does it hurt the most? From that point, does your pain go anywhere else? Somatic pain is localized; visceral pain is diffuse and radiates.
• Severity: Rate your pain on a scale of 1 to 10. (Our treatment goal is to lessen the patient's perceived pain.)
• Time: When did your pain start, or how long have you had this pain? Somatic pain starts at the time of injury. Neuropathic pain might persist for weeks or months before a patient's life becomes so dysfunctional that he seeks care.⁷

PAIN-ASSESSMENT SCALES
The numerical, verbal and visual analog scales are one-dimensional pain-rating scales for adults. Every EMS service should choose a pain-assessment tool, train to use it and document its use in the field.³

The numerical rating scale is the most commonly used.⁴ It is easy to use and can be used prior to and repeatedly after treatment. Ask patients to "rate your pain on a scale from 1 to 10, with 1 being no pain at all and 10 being the worst pain you can imagine."

To complete a verbal rating scale, give the patient a sheet of paper listing five pain levels: no pain, mild pain, moderate pain, severe pain and unbearable pain. Ask the patient to "indicate which phrase best corresponds with your level of pain."³ This rating scale is effective with literate patients who have no vision impairment.

The visual analog scale is a 100 mm ruler marked with "no pain" at the left end and "most intense pain imaginable" at the right end. Patients are asked to indicate their level of pain by sliding a cursor on the ruler to the level that best matches their pain.³

The Wong-Baker Faces Pain Scale (see Figure 1) is a visual rating scale where the patient is shown a lineup of eight faces wearing different expressions and is asked to select the face he feels best reflects his current pain.⁴ The Faces Pain Scale is indicated for adults and children older than age three and is available in English and Spanish versions.

ASSESSMENT CHALLENGES
Underlying illness and disabilities complicate standard patient assessment. Other pain assessment challenges include assessing pain in infants, children and geriatric patients; adults with cognitive disturbances; cultural, educational and language barriers; intubated patients and seriously ill patients.⁴

To overcome communication challenges, be patient and take your time. Patient self-reporting and use of a pain scale appropriate to the patient is most useful. Use your medical knowledge: Is the patient's condition known to be painful? Use behavioral and physiological indicators only when other alternatives are not available. Is the patient exhibiting pain-related behaviors? What insights can family or caregivers report? Finally, check vital signs. Some painful conditions correlate to vital sign changes.

Parents and medical providers consistently underestimate the severity of pain in infants and small children, who are unable to use pain-rating scales. Look for behavioral and physiological clues like grimacing, tears, increased pulse and respiration, and fever to understand the child's pain.⁶

Several pediatric pain assessment tools have been developed to assess pediatric pain. The CRIES pain scale is indicated for neonates, zero to six months, and assesses crying, oxygen required to maintain oxygenation, increased vital signs, expression and sleeplessness.

The FLACC Scale is indicated for infants and children age two months to seven years who are unable to self-report pain. FLACC assigns a score for the child's facial expression, position and movement of legs, amount and control over activity, crying and ability of the parent or care provider to console.

Pain is the most common complaint of older Americans and increases with aging, often due to chronic diseases.⁶ One in five older Americans regularly takes pain medications. Common assessment problems with geriatric patients include hearing and vision loss, complicated underlying illness and difficulty processing information. Before shouting questions at the patient, work slowly to determine mental status, sensory function and cognitive ability. If your patient is unable to self-report pain, use behavioral clues and physiologic measurements for assessment.⁶

A dementia patient who had fallen out of bed answered every question with "yes." Does it hurt? "Yes." Where does it hurt? "Yes." Cognitive deficits from strokes, dementia or head injury alter mental status and may make patients unable to express their pain. Without a reliable self-report from the patient, we used other clues: a large bruise to the upper right chest, increased respiratory rate and effort, restlessness, inability to find a position of comfort, pushing away attempts to palpate the injured area and reduced right chest sounds. If it looks painful and seems like it should be painful, treat it as if it is painful.

A 40-year-old female with 10 self-inflicted, two-inch superficial lacerations to her abdomen is severely depressed and suicidal. She does not complain of pain and is unwilling to discuss pain in relation to her wounds. Emotions affect pain, and pain assessment depends on the emotions of the person experiencing the pain.⁶

In prehospital care, intubated patients are usually unresponsive or significantly sedated. Nonetheless, be aware that serious illness and intubation can compromise a patient's ability to express pain. For a terminal cancer patient, movement from a chair to the ambulance cot or a bump in the road could cause agonizing pain. Take your time if the patient is nonemergent, explain your actions before acting and talk to the patient. Do whatever is most comfortable for them. If you are uncertain about pain assessment for seriously ill patients, contact medical control.

Pain Classification
One of several methods used to classify pain is duration: acute-short duration or chronic-long duration.⁴ Causes of common acute pain are trauma, surgery, childbirth and disease.⁴ Duration for acute pain, while relative to time, really means the lessening of pain as the condition heals.

If you slam your thumb in the car door, there is a three-phase response--behavioral, sensory and emotional--to the acute pain. Before your brain perceives the pain, you reflexively jerk your arm (behavioral response) away from the car door. You cry out and hold your thumb (sensory response), then react (emotional response) by becoming angry at yourself for not moving your hand.

Chronic pain, like acute pain, is not based on a set time length. Rather, chronic pain extends beyond the expected healing period, is disproportionate to observable causes, and is persistent and disruptive to normal life. Chronic pain results from injury, disease, cancer, arthritis, fibromyalgia and nerve damage.⁴

Another pain classification scheme is based on pathophysiology. Pain pathophysiology is either nociceptive or neuropathic.^4,5 Nociceptive pain originates from damage to somatic-musculoskeletal tissue or visceral-internal organ tissue.⁵ Nociceptors are the body's pain receptors and are found in both somatic and visceral tissue.

Somatic pain activates pain receptors in the skin and deep musculoskeletal tissues. Common causes are trauma, burns, sprains, wounds or muscle strains.⁷ The patient is usually able to localize the source of pain.

Visceral pain is caused by ischemia, infiltration, compression, distention, torsion or stretching of organs.⁷ Examples are appendicitis or myocardial infarction. Visceral pain is often poorly localized, such as a heart attack that causes radiating left arm pain, with accompanying symptoms of nausea, vomiting and diarrhea.⁷

Neuropathic pain is a result of nervous system injury or impairment and is categorized as centrally or peripherally generated.^4,5 Unlike nociceptive pain, it is much more difficult to identify a cause of neuropathic pain during a prehospital patient assessment, as there may be a significant delay between the onset of pain and perception. The pain reported is often disproportionate to exam findings, and may be severe and unrelenting.^5,7

Causes of centrally generated pain include stroke, brain tumors and spinal cord injury that damages the central nervous system.⁴ Symptoms include burning, numbness and tingling, and reduced or increased sensation.

Peripherally generated pain is pain along one or more peripheral nerve pathways caused by damage to the nerve or affected nerves. The pain is either continuous or comes in shock-like waves. Causes of peripherally generated pain include diabetes, toxins like alcohol or chemotherapy, infection or trauma, like a "pinched nerve."⁴

CONCLUSION
Assess every patient's pain by measuring vital signs, completing a physical examination, collecting history information, observing the patient's pain-related behaviors and using valid pain assessment tools. Combine assessment findings with an understanding of how the body communicates pain to help alleviate your patient's suffering.

References

1. Abbuhl FB, Reed DB. Time to analgesia for patients with painful extremity injuries transported to the emergency department by ambulance. Prehosp Emerg Care 7(4), Oct/Dec 2003.

2. Bledsoe BE, Myers J. Pain and comfort: The pathophysiology of pain and prehospital treatment options. JEMS 28(6), 2003.

3. Alonso-Serra HM, Wesley K. Position Paper: Prehospital Pain Management. Prehosp Emerg Care 7(4), Oct/Dec 2003.

4 American Pain Society. Pain: Current understanding of assessment, management, and treatments. American Pain Society. Glenview, Illinois. www.ampainsoc.org/ce/npc/.

5. McCaffery M, Pasero C. Pain: Clinical Manual, 2nd Edition. St. Louis, MO: Mosby, 1999.

6. Upchurch J. The face of pain: How to assess and manage patient pain in the field. JEMS 28(6), 2003.

7. Wesley K. Pain: Understanding and Treating It. EMS Professionals. Wisconsin EMS Association. Nov/Dec 2000. www.wisconsinems.com/docs/Pain.htm.

8. Rodenberg H. Improving pain control in the field. www.jems.com/jems/exclus03/e0103.html.

9. National Institutes of Health Pain Consortium. Wong-Baker Faces Pain Rating Scale. https://painconsortium.nih.gov/pain_scales/Wong-Baker_Faces.pdf, July 2003.

10. National Institutes of Health Pain Consortium. CRIES Pain Scale. https://painconsortium.nih.gov/pain_scales/CRIESPainScale.pdf, July 2003.

11. National Institutes of Health Pain Consortium. FLACC Scale. https://painconsortium.nih.gov/pain_scales/FLACCScale.pdf, July 2003.

Greg Friese, MS, NREMT-P, is president of Emergency Preparedness Systems LLC, which helps clients rapidly deploy emergency education. Greg and EPS associates have authored and edited dozens of RapidCE.com online education programs. Friese is also a Wilderness Medical Associates lead instructor. Contact him at gfriese@eps411.com.

Randal F. Wojciehoski, DPM, DO, is an emergency physician at Saint Michael's Hospital-Ministry Health Care in Stevens Point, WI. As a syndicated newspaper columnist and author of To Your Health With Dr. Wojo, he has also authored or coauthored a variety of articles on emergency medicine. Contact him through his website, www.drwojo.com.

Amanda Friese, RN, BSN, is an emergency department registered nurse at Saint Michael's Hospital in Stevens Point, WI.