2013 EMS Understanding pain


Published on

This is a detailed lecture on introduction to pain management for EMS providers. It was originally written for the new AEMT class, but would serve as a start for any medic class as well. NOTE: It does not include drug doses for opioids and benxo's, as this was written for AEMT, but that would be an easy fix for any Medic Program. Estimated time for delivary 2 hours.

Published in: Health & Medicine
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide
  • In 1975, well after the time of Descartes, the International Association for the Study of Pain sought a consensus definition for pain, finalizing "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage" as the final definition.[17] It is clear from this definition that while it is understood that pain is a physical phenomena, the emotional state of a person, as well as the context or situation associated with the pain also impacts the perception of the nociceptive or noxious event. For example, if a human experiences a painful event associated with any form of trauma (an accident, disease, etc.), a reoccurrence of similar physical pain will not only inflict physical trauma but also the emotional and mental trauma first associated with the painful event. Research has shown that should a similar injury occur to two people, one person who associates large emotional consequence to the pain and the other person who does not, the person who associates a large consequence on the pain event will feel a more intense physical pain that the person who does not associate a large emotional consequence with the pain.
  • As long as humans have experienced pain, they have given explanations for its existence and sought soothing agents to dull or cease the painful sensation. Archaeologists have uncovered clay tablets dating back as far as 5,000 BC which reference the cultivation and use of the opium poppy to bring joy and cease pain. In 800 BC, the Greek writer Homer wrote in his epic, The Odyssey, of Telemachus, a man who used opium to soothe his pain and forget his worries.[1] While some cultures researched analgesics and allowed or encouraged their use, others perceived pain to be a necessary, integral sensation. Physicians of the 19th century used pain as a diagnostic tool, theorizing that a greater amount of personally perceived pain was correlated to a greater internal vitality, and as a treatment in and of itself, inflicting pain on their patients to rid the patient of evil and unbalanced humors.[2] This article focuses both on the history of how pain has been perceived across time and culture, but also how malleable an individual's perception of pain can be due to factors like situation, their visual perception of the pain, and previous history with pain.Portriat is of Rene’ Descartes
  • Henry Knowles Beecher (February 4, 1904[1] – July 25, 1976[2]) was an important figure in the history of anesthesiology and medicine, receiving awards and honors during his career. His1966 article on unethical practices in medical experimentation within the New England Journal of Medicine was instrumental in the implementation of federal rules on human experimentation and informed consent.[3] A 1999 biography—written by Vincent J. Kopp, M.D. of UNC Chapel Hill and published in an American Society of Anesthesiologists newsletter—describes Beecher as an influential figure within the development of medical ethics and research techniques, though he has not been without controversy.[4] He has been implicated in human experiments with the OSS/CIA in the 1950’s and 60’s as wellAn opportunity to do this was made possible during the prolonged action on the Venafro andCassino Fronts and later at the Anzio Beachhead and in France.
  •  In 1965, the Canadian psychologist Ronald Melzack and the British physiologist Patrick Wall proposed that the Cartesian model be replaced with what they called the gate-control theory of pain. Melzack and Wall argued that before pain signals reach the brain they must first go through a gating mechanism in the spinal cord which could ratchet them up or down. ... Melzack and Wall’s most startling suggestion was that what controlled the gate was not just signals from sensory nerves but also emotions and other “output” from the brain. ... Ref: Melzack R. The puzzle of pain. New York: Basic Books; 1973. ISBN 465067794.Gate control theory[edit]Ronald Melzack and Patrick Wall introduced their "gate control" theory of pain in the 1965 Science article "Pain Mechanisms: A New Theory".[15] The authors proposed that both thin (pain) and large diameter (touch, pressure, vibration) nerve fibers carry information from the site of injury to two destinations in the dorsal horn of the spinal cord: transmission cells that carry the pain signal up to the brain, and inhibitory interneurons that impede transmission cell activity. Activity in both thin and large diameter fibers excites transmission cells. Thin fiber activity impedes the inhibitory cells (tending to allow the transmission cell to fire) and large diameter fiber activity excites the inhibitory cells (tending to inhibit transmission cell activity). So, the more large fiber (touch, pressure, vibration) activity relative to thin fiber activity at the inhibitory cell, the less pain is felt. The authors had drawn a neural "circuit diagram" to explain why we rub a smack.[5] They pictured not only a signal traveling from the site of injury to the inhibitory and transmission cells and up the spinal cord to the brain, but also a signal traveling from the site of injury directly up the cord to the brain (bypassing the inhibitory and transmission cells) where, depending on the state of the brain, it may trigger a signal back down the spinal cord to modulate inhibitory cell activity (and so pain intensity). The theory offered a physiological explanation for the previously observed effect of psychology on pain perception.[16]Gate control theory expressed in simplified form proposes that when pain (C and A-delta) fibers are stimulated, pain impulses are passed presynaptically in the SG and are transmitted to thebrain, and they will be perceived and will continue to be felt as pain as long as the stimulus persists. Relief of pain is dependent on stimulation of the large myelinated A-beta fibers which normallytransmit the perceptions of touch and pressure. A-beta fiber stimulation results in an inhibitory effect setup in the same area of the SG where pain fibers synapse with a decrease in transmission orclosing the gate to pain. Cessation of large fiber stimulation would remove the inhibition of pain in the SG and open the gate to the transmission and perception of pain. This theory seems to explain relief of pain by electrical stimulation of large nerve fibers but does not rule out the possibility of undetected postsynaptic control mechanisms.
  • Visual input and pain perception[edit]Additional research has shown that the experience of pain is shaped by a plethora of contextual factors, including vision. Researchers have found that when a subject views the area of their body that is being stimulated, the subject will report a lowered amount of perceived pain.[18] For example, one research study used a heat stimulation on their subjects' hands. When the subject was directed to look at their hand when the painful heat stimulus was applied, the subject experienced an analgesic effect and reported a higher temperature pain threshold. Additionally, when the view of their hand was increased, the analgesic effect also increased and vice versa. This research demonstrated how the perception of pain relies on visual input.The use of fMRI to study brain activity confirms the link between visual perception and pain perception. It has been found that the brain regions that convey the perception of pain are the same regions that encode the size of visual inputs.[19] One specific area, the magnitude-related insula of the insular cortex, functions to perceive the size of a visual stimulation and integrate the concept of that size across various sensory systems, including the perception of pain. This area also overlaps with the nociceptive-specific insula, part of the insula that selectively processes nociception, leading to the conclusion that there is an interaction and interface between the two areas. This interaction tells the individual how much relative pain they are experiencing, leading to the subjective perception of pain based on the current visual stimulus.Humans have always sought to understand why they experience pain and how that pain comes about. While pain was previously thought to be the work of evil spirits, it is now understood to be a neurological signal. However, the perception of pain is not absolute and can be impacted by various factors in including the context surrounding the painful stimulus, the visual perception of the stimulus, and an individual's personal history with pain.
  • Dr. Frederick Lenz whose findings suggest that all pain is "in the head" and that sometimes, as in two cited cases, a physical injury isn't needed to make a pain system go haywire. This is the newest theory of pain and is being advanced by Melzack, among others... Describes new anti-pain drugs, some originally developed as anti-epileptics, including one from the venom of the Conus sea snail, Ziconotide, and another from an Ecuadorian poison frog, ABT-594... Some forms of chronic pain behave astonishingly like social epidemics... Writer concludes that a compassionate approach toward chronic pain means investigating its social coordinates, not just its physical ones. For the solution to chronic pain may lie more in what goes on around us than in what is going on inside us. Of all the implications of the new theory of pain, this one seems to be the oddest and the most far-reaching: it has made pain political.
  • It is believed that the psychology of a competitive culture, the discipline needed to be a professional ballet performer, and the high rate of chronic pain and chronic injuries raise the tolerance.
  • JCAHO recognized that the undertreatment of pain is an important public health problem, and attempts to address the problem through the implementation of systemic reforms. The JCAHO pain standards affirm that:1. Patients have the right to appropriate assessment and management of pain.2. Institutions must respect and support patients’ rights to pain management. And,3. Patients have a right to expect that their pain reports will be believed and to receive a quick response to reports of pain.
  • Other contraindications Altered/decreased level of consciousnessHead injuriesChest injuries (blunt or penetrating)Intoxication or drug ingestionMaxillofacial injuriesPsychiatric problemsCOPD, emphysema, or any condition that may compromise respiratory efforts including: CHF, respiratory tract burns, other trauma < 12 years of age or less than 75 poundsOB patient not in the process of deliveryRespiratory distressBowel obstruction or traumatic abdominal injuryInner ear pain
  • Male and female incidence is equal, with an average age range from 30 to 50 years old. These patients generally share common risk factors of heavy lifting or twisting, obesity, and poor conditioning
  • 2013 EMS Understanding pain

    1. 1. Non-Traumatic Pain Advanced EMT Class
    2. 2. What is pain? • "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage" • - 1975 , International Association for the Study of Pain
    3. 3. “There is a common belief that wounds are inevitably associated with pain, and, further, that the more extensive the wound the worse the pain. Observation of freshly wounded men in the combat zone showed this generalization to be misleading…..” LTC Henry K Beecher, Medical Corps, Army of the United States
    4. 4. Objectives • Review types of Pain • Discuss assessment of Pain • Review and Discuss common non-traumatic (and non-cardiac) causes of pain • Review common treatment modalities
    5. 5. Pain and EMS • Approximately 15% of EMS calls are for a primary complaint of pain… • Many more have it as a secondary complaint • Whether our patients are suffering from a traumatic, medical or psychological condition, a common thread throughout many of our calls is pain. • Definition from the International Association for the Study of Pain: “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage…”
    6. 6. Pain Serves a Purpose • It tells us something is wrong with our body that we can’t see otherwise • Appendicitis • Internal bleeding • It helps us avoid dangerous things • We touch a hot stove, we feel pain, we pull away • It helps us protect damaged body parts • We shield injuries from accidental contact with other people or things
    7. 7. The Bad Side of Pain • While pain serves an important purpose, it also presents a barrier to normal functioning • Pain negatively affects: • Attention • Memory • Mental flexibility • Problem solving • Information processing speed • Stress levels
    8. 8. Pathophysiology…and psychology …of pain
    9. 9. Pain….. • Rene’ Descartes • Cartesian Theory of pain • French Philosopher that first proposed that pain was a disturbance that passed down along nerve fibers until the disturbance reached the brain.
    10. 10. What Causes Pain? • Pain signals are sent to our brain by nociceptors (no-si-sep-tors) • A nociceptor responds to damaging stimuli (heat, pressure, etc.) by sending nerve signals to the spinal cord and brain. • This process, called nociception (no-si-sep-shun), is what causes the feeling of pain.
    11. 11. The Pain Pathway (tutorvista.com)
    12. 12. Is it this simple? • In everyday medicine, doctors see pain in Cartesian terms—as a physical process, a sign of tissue injury. • We have known that this is not the “full picture” since the early 1900’s.
    13. 13. Pain has a psychological and a social- situational aspect • Lt. Col. Henry K. Beecher (WWII) wrote: “ Pain in wounded men in battle”. Studied 225 soldiers at a various forward aid stations at multiple major engagements. • 58 % with severe injuries reported only slight or no pain • On 27 % felt enough pain to request pain medication • This flys in the face of traditional Cartesian understanding of pain. • Proposed that there were THREE main components of pain… • Mental Distress • Thirst, dehydration, and discomfort • Pain from injuries • Goes on to write that medical treatment has been mainly focused on the painful injury, and ignoring the psychological and social aspects.
    14. 14. Gate- Control Theory • Builds on the Cartesian theory of pain, but states that the pain impulses go through “gates” in the spinal chord. These gates have the ability to mute, eliminate, or amplify pain. • They also state that there are physiological and psychological factors that influence these “gates”. Melzack R. The puzzle of pain. New York: Basic Books; 1973. ISBN 465067794.
    15. 15. Visual cues affect pain perception • Additional research has shown that the experience of pain is shaped by a plethora of contextual factors, including vision. • Researchers have found that when a subject views the area of their body that is being stimulated, the subject will report a lowered amount of perceived pain. • For example, one research study used a heat stimulation on their subjects' hands. When the subject was directed to look at their hand when the painful heat stimulus was applied, the subject experienced an analgesic effect and reported a higher temperature pain threshold. • Additionally, when the view of their hand was increased, the analgesic effect also increased and vice versa. This research demonstrated how the perception of pain relies on visual input. Mancini, Flavia. "Visual Distortion of Body Size Modulates Pain Perception." Psychological Science. (2010): n. page. Web. 9 Dec. 2011.
    16. 16. Sometimes we don’t even need an injury to make pain occur. • If I say “Pain is all in the head” what do you think that means?
    17. 17. Neuro-Programs? • If Y = Pain response… • What if? • If X then Y • What if Z then Y? • What if (ABC), but not (CBA), then Y? • What if (null) then Y? • Melzack , et al, proposes that acute pain is “Lateral Pain” wich skips along the outside of the brain stem, and chronic pain is “Medial Pain” which passes directly through the brain stem. • The fore he proposes that each type of pain is actually different disease processes with different approaches.
    18. 18. Classifications of Pain (from Mosby’s Paramedic textbook) • Acute – sudden in onset, subsides with treatment • Chronic – persistent or recurrent, hard to treat • Referred – pain felt somewhere other than its origin • Heart attack felt in arm • Spleen rupture felt in shoulder • Gall bladder felt in shoulder blade
    19. 19. Classifications of Pain (from Mosby’s Paramedic textbook) • Somatic – pain in muscles, ligaments, vessels, joints • Superficial – pain in skin, mucous membranes • Visceral – “deep” pain, hard to localize, arises from smooth muscles or organ systems
    20. 20. Referred Pain • Pain that originates in a region other than where it is felt • Arm/Jaw Pain Acute Coronary Syndrome • Pain between Dissecting shoulder blades Thoracic Aortic Aneurysm - Shoulder Pain Liver Injury (Paramedic Care: Principles and Practice)
    21. 21. Some other kinds of pain • Neuropathic – caused by damage or disease to the nervous system • Tingling, burning, electrical “zapping” • “Pins and needles” • Bumping the “funny bone” • Psychogenic – caused by mental, emotional, or behavioral factors • No less hurtful than pain from other sources • Not “all in their head”
    22. 22. Phantom Pain • Phantom – felt after limb is amputated • Nerve endings to stump become “confused” • Signal pain to the brain even though the limb is no longer there.
    23. 23. Inability to Feel Pain • Some people can’t feel pain like they should • Diabetic neuropathy • Spinal cord injury • Congenital disorders • More prone to injury due to lack of “warning” • May be shorter life span due to increased injury risk
    24. 24. Pain Tolerance • Several studies over the years have shown women typically display lower pain tolerance than men. • Unknown whether reason is hormonal, genetic or psychosocial. • Researchers suggest men more tolerant of pain because of “macho” stereotyping, while feminine stereotyping encourages pain expression.
    25. 25. Pain Tolerance • On the other hand, the show “Mythbusters” recently found women to be more tolerant of pain than men, so stereotypical responses may be changing over time.
    26. 26. On the other, other hand…. • Melzack and Walls Ballet Study: • 52 Dancers from British Ballet company • 53 physicaly fit university students • “Cold Compressor” Test • Place hand in room temp water for two minutes-> immerse in ice water-> TIME: Pain felt (Pain THRESHOLD) -> Pain is too much to keep hand in (Pain TOLORANCE) • Results: Males tended to last longer than women in both groups. BUT, dancers tended to last 3x as long as the students. Why?
    27. 27. Placebo effect: • Foolish or simply recruiting the patients mind (the psychological component )in pain management? • Should we lie to our patients? • Should we manage expectations?
    28. 28. Some other things to consider • There is some thought that some panic disorders and some pain disorders (and the chest pain associated with them) originate from the same part of the brain (the Thalamus) • Social factors have been known to strongly effect pain perception and epidemiology. • Satisfying work environment • Marriage/relationships • Stress
    29. 29. KEY POINT: • Pain that arises from a psychological/social origin is no less real to the patient than one arising from a physical injury. Only the effective therapies may be different.
    30. 30. Assessing Pain
    31. 31. What is pain? "Those who do not feel pain seldom think that it is felt." - Dr Samuel Johnson (1709-1784)
    32. 32. Assessing Pain • The most basic way to characterize pain is the 1-10 scale (some use 0- 10). • All reports/narratives with patients in pain should include a 1-10 rating both before, and after, treatment • 1 (or 0) = no pain • 10= worst pain ever felt
    33. 33. Assessing Pain • For children and others with difficulties understanding the 1-10 scale, you can use the Wong-Baker scale • Also called the “smiley face” scale • They point to the picture that best describes their pain.
    34. 34. Wong-Baker Scale
    35. 35. Assessing Pain - OPQRST • All narratives for pain and injury should include some form of OPQRST • O – Onset (when did pain start) • P – Palliation/Provocation (what makes it better or worse) • Q – Quality (what does it feel like) • R – Radiation (does it move anywhere) • S – Severity (1-10 scale) • T – Time (can be combined with O, or can refer to whether it comes and goes or is steady) • You don’t have to specifically reference each letter in your report. • Like any mnemonic, it’s more to help you remember important assessment questions, than to actually be used word-for-word. • But if the information is relevant, it needs to be included somehow.
    36. 36. Assessing Pain • What does patient look like? • Obvious distress? • Guarding injured limb? • Yelling? • Calm and controlled? • Tense? • Does the patients presentation match the report of pain?
    37. 37. Assessing Pain • Remember DCAP-BTLS? • All painful or injured body parts need to be exposed and examined. • And all examinations need to be documented. • Exception – obvious cardiac chest pain, but if you are putting on EKG leads, you might as well examine and document anyway since you are there.
    38. 38. Assessing Pain – Head-to-Toe • Depending on the mechanism of injury or the nature of the illness, a head-to-toe exam may be called for too. • Document all head-to-toe exams. If it’s not written down, it wasn’t done. • Don’t let severe pain from one part of the body distract you from injuries on other parts of the body.
    39. 39. Assessing Pain - Peds • Sometime starting at the toes and working your way up to the head works better with kids. • May be less likely to freak out. • “No Surprises” Policy – • Kids fear the unknown, and they fear being alone. • Keep it simple and in the “Now” • They fear “Forever” • Kids are the kings and queens of distracting injuries. • They don’t understand why a bloody finger is less important than a deformed leg. • Take extra care in examining a child in pain
    40. 40. Pain Management
    41. 41. Pain Management • Because pain has as many bad aspects as good, our goal in EMS is to control pain whenever possible. • Joint Commission (JCAHO) says pain is 5th vital sign after BP, pulse, respiratory, and temp. • The goal – ZERO PAIN!
    42. 42. Why Zero Pain? • Cardiac chest pain – zero pain means less stress on the patient, lowering pulse and BP, leading to less work for the heart • Musculo-skeletal pain – zero pain means your patient is more cooperative, less disruptive and better able to follow directions
    43. 43. When is zero pain not the goal? • There are a few times in EMS when we don’t want to treat pain • Headache – pain medication can mask symptoms of a more serious head injury • Abdominal pain – pain location is often used for diagnosis of new-onset abdominal pain • Drug-seeking patient – trust your instincts • If you suspect patient is a drug-seeker, let medical control know your suspicions (out of earshot of patient)
    44. 44. When are we extra- cautious with pain control? • Patient is already self medicated • Alcohol • Head Injury/Altered LOC • Borderline Blood Pressure • Elderly
    45. 45. Dr. Kraners theory of pain control and blood pressure • That most opioids are not as vasoactive as previously thought • That it is the pain that is “vaso-active” in keeping blood pressure up. • If we see a severe drop after administering analgesia, perhaps somne of that is the actual underlying blood pressure • If we are relying on the pain response (i.e. adrenalin and nor-epi) to keep blood pressure up, we may be promoting cellular hypo- perfusion through capillary vaso –constriction • Solution- Medicate conservatively and fluid resuscitate unless contraindicated.
    46. 46. EMS and Pain • Prehospital Emergency Care, Jul-Sep 2010… pain in prehospital emergency medicine affects 42% of patients…. Pain management is inadequate, as only one in two patients experiences relief.” • American Journal of Emergency Medicine, Oct 2007… “women are less likely than men to receive prehospital analgesia for isolated extremity injuries… Increasing levels of income were associated with increased rates of analgesia.”
    47. 47. Why are we not treating pain adequately? • Biases and prejudices? • Poor patients, patients we think are faking it, patients who are “whiners” • Fear of medication administration? • Giving narcotics is a big responsibility, especially if we are not comfortable with our skills and math ability • Administrative and logistical hurdles? • Narcotics control procedures cumbersome • Push back from chain of command for being bothered with narcotics procedures.
    48. 48. Discussion Questions • Why don’t we relieve pain? • Obstacles to pain management • Options for ALS providers
    49. 49. Why are we not treating pain adequately? • Our own emotional reaction to someone in pain? • Our anxiety can cloud our judgment regarding treatment • A screaming patient makes even the best medic second-guess • Past issues with medical control regarding medication administration? • In the old days, paramedics often got hassled for attempting ALS pain management. Sometimes, they still do.
    50. 50. Non Pharmacological Treatment of Pain
    51. 51. Pain pharmacology/treatment • Pain medications/treatments address two components of pain: • The actual sensation of pain • The emotional response to pain • We carry medications and treatments on the ambulance that address both components • Don’t forget BLS treatments… often just as effective as ALS medications, and easier too.
    52. 52. Cold Packs • Cold packs often a forgotten element of pain management. • Remember the “Gate Control Theory”? • In addition to reducing swelling, there is a theory that cold “Opens” the gate for cold sensation impulses, decreasing the actual pain impulses that get through. • Reduce swelling and pain in strains, sprains and fractures. • When possible, do not put directly on injured area. • Can cause tissue damage • Wrap in pillow case or gauze first
    53. 53. Splinting • Splinting used to stabilize damaged bone ends, or injured muscles/ligaments. • But also useful in reducing pain caused by movement of injured areas. • Whether a commercial splint, or a pillow and tape… a splint is powerful weapon against pain. • Traction splint significantly reduces pain of femur fracture by easing muscular contraction • Check distal pulses, movement and feeling (“MSC”, “CMS”, “PMS”) before/after splinting.
    54. 54. Distraction? • Conversation • Music • Video
    55. 55. Pharmacological Interventions
    56. 56. The Ideal Analgesic • Safe with few side effects • Effective and rapid acting • Easy to administer, store, and carry • Of short duration and easily reversible • Not easily abused
    57. 57. Opioids/Opiates • Scrolls describing its use date back almost 5000 years • Bind with opioid receptors in the brain and elsewhere • Alters perception of pain • Alters emotional response to painful stimulus Drugandalcoholrehab.net
    58. 58. Opioids • Commonly carried by EMS • Chief alkaloid of opium • Carried by prehospital crews because • It’s cheap • It’s been around a long time • It works without too much fuss • It’s easy to treat if we give too much of it • Ventilation and Narcan
    59. 59. Common Opioids • Morphine • Fentanyl • Dilaudid • Demerol
    60. 60. Opioid side-effects • Respiratory depression • Nausea/vomiting • Constipation • CNS depression • Careful administration can prevent many of these side-effects
    61. 61. Benzodiazepines/Sedatives • Benzo’s are used in many EMS systems for drug- assisted intubation, seizure control and chemical restraint. • Some systems also order a benzodiazipine as muscle relaxant in long bones fractures, back injuries, and hip fractures. • Also to reduce anxiety in patient with pain. • Versed (A type of benzo) given to reduce pain of cardioversion and pacing, as well as to induce amnesia.
    62. 62. Benzodiazepines/Sedatives • Benzo’s are sedatives, similar to opioids but working through a different mechanism. • GABA • Same mechanism that Alcohol causes its sedative effects.
    63. 63. Common Benzo’s • Diazepam (Valium) • Midazolam (Versed) • Lorazepam (Ativan) Not used in EMS: • Clonazepam (Xanex) Prince Valium, from the Princess Bride
    64. 64. Anesthetics • Anesthetics are CNS depressants. • Act on nervous tissue • Two main anesthetics in EMS system • Tetracaine – local anesthetic • 1 to 2 drops as needed for (closed) eye injury • Nitrous oxide – inhaled anesthetic • Broken bones, non-respiratory burns, kidney stones • 50/50 concentration with oxygen • Contraindications – AMS, shock, abd trauma, facial injuries, COPD, head injury
    65. 65. Nitronox-Properties • Blended mixture of 50% nitrous oxide and 50% oxygen • Also known as “laughing gas” • Produces sedation and analgesia • Colorless, odorless, heavier than air • Nonexplosive, nonflammable • Readily diffuses through membranes (rapid onset, short duration after inhalation is stopped) • Provides a sedative effect which decreases the patients perception of pain • May partially act on opiate receptor systems to cause mild analgesia
    66. 66. Nitrous Oxide • Drug Name: Nitrous Oxide, N2O • Trade Name: Entonox, Nitronox • Class: Inhaled gas, dissociative anesthetic • Mechanism of Action: • The pharmacological mechanism of action of N2O in medicine is not fully known. It appears to have multiple , diverse, neurochemical effects in the body, mainly in the central nervous system. It produces its analgesic, hallucinogenic, and euphoric effects through effects on dopamine, opioid, GABA and seratonin receptors. • It is absorbed, and eliminated via the respiratory system. It does not accumulate for any significant period, but tolerance has been known to develop similar to opioids. •
    67. 67. Nitrous Oxide • Indications: • Painful injuries • Contraindications: • Inability of the patient to hold mouthpiece or control their own airway. • Hypoxia • Suspected bowel obstruction • Abdominal Injury • Suspected Pneumothorax, • inner/Middle ear disorders • SCUBA diving within previous 24 hours.
    68. 68. Nitrous Oxide • Precautions: • Psychiatric Emergencies • Use of opioids, alcohol, and benzodiazepines • While it has been used in pregnancy and during labor, thereis some evidence that it may increase the incidence of spontaneous abortion. use only with medical control approval in pregnant patients. • Dosage: • Adults: Self administered at pre-set levels. • Pediatrics: Self administered at pre-set levels. • EMS Nitronox typically comes in a 50/50 mixture
    69. 69. Nitrous Oxide • PEARLS: • Nitrous Oxide typically comes pre-mixed with 50% Oxygen. It is typically administered via a demand valve, mouth peice or a mask. • Nitrous Oxide is ineffective in up to 20% of the population. • Nitrous oxide is more soluble than oxygen and nitrogen, so will tend to diffuse into any air spaces within the body. This makes it dangerous to use in patients with pneumothorax or who have recently been scuba diving, and there are cautions over its use with any suspected bowel injury or obstruction. • Its analgesic effect is strong (equivalent to morphine ) and characterised by rapid onset and offset (i.e. it is very fast-acting and wears off very quickly). • Cautious use in enclosed spaces 
    70. 70. Nitronox Administration • ALWAYS SELF – ADMINISTERED BY PATIENT WHO IS AWAKE, ALERT, AND COOPERATIVE! • Instruct patient to inhale deeply through the patient-held demand valve • Patient determines number of inhalations and duration of therapy required for adequate pain relief
    71. 71. Delivery Unit • Supplied in carrying case containing 2 cylinders, 1 nitrous oxide and 1 oxygen • Mixing valve ensures premixed 50:50 delivery of gas • Demand valve prevents free flow of gas when not in use by patient • Negative pressure required to open demand valve (good seal and patient effort)
    72. 72. Delivery Unit (cont.) • If oxygen tank runs out- audible alarm and no gas delivery • If nitrous oxide tank runs out- audible alarm with 100% oxygen delivery to patient
    73. 73. Take a break…
    74. 74. Some specific examples
    75. 75. Chest Pain • Initial treatment does include aspirin • But not for pain, for better cardiac outcome • ZERO pain comes from: • Nitro – vasodilates, reduces workload of heart • If initial nitro doesn’t reduce pain, repeat x2 in 5 minute increments if BP > 90 systolic and IV established • Opioids – reduces muscle pain, reduces stress, reduces workload of heart (reduces preload)
    76. 76. Isolated Extremity Injury • First control bleeding with direct pressure and elevation. • Splint fractures, sprains and strains • BLS – a cold pack can reduce swelling and pain • ALS – nitrous oxide can help with fractures • If patient is able to self-administer w/injuries • ALS – Opioids • No opioids if hypotension from blood loss.
    77. 77. Back Pain • Though the yearly prevalence is stable at 15% to 20%, nearly 80% of adults will experience back pain at some point during their lifetime, with 31% of patients annually requiring time off from work • Varies from acute, to chronic, and acute exacerbation of chronic pain
    78. 78. Back Pain • Muscle strain and spasm • Lumbar • Diffuse right and/or left • Palpable tetany of muscles • Classic Presentation: Doesn’t want to move… • Sciatica • “Sciatic Pattern” • May or may not be associated with muscle spasms
    79. 79. Kidney Stones • Classic presentation: • Sudden Onset • Flank Pain • “Cant find position of comfort” – Squirmy • Severely decreased urine • Hematuria
    80. 80. Generic Abdominal Pain • Regarding Abdominal Pain: Narcotic analgesia was historically considered contraindicated in the pre-hospital setting for abdominal pain of unknown etiology. It was thought that analgesia would hinder the ER physician or surgeon's evaluation of abdominal pain. It is now becoming widely recognized that severe pain actually confounds physical assessment of the abdomen and that narcotic analgesia rarely diminishes all of the pain related to the abdominal pathology. • It would seem to be both prudent and humane to "take the edge off of the pain" in this situation with the goal of reducing, not necessarily eliminating the discomfort. Additionally, in the practice of modern medicine the exact diagnosis of the etiology of abdominal pain is rarely made on physical examination. • Advancement in technology and availability has made laboratory, x-ray, ultrasound, CT scan, & occasionally MRI essential in the diagnosis of abdominal pain. • Therefore medication of abdominal pain is both humane and appropriate medical care. • NOTE: Nitrous is not a good option for Abdominal Pain management
    81. 81. Chronic Pain
    82. 82. Chronic Painwww.webmd.com • Defined as pain that lasts longer than six months. • Can be mild or excruciating, episodic or continuous, inconvenient or incapacitating. • May originate with an initial trauma/injury or infection, or an ongoing medical cause. • Or can have no cause at all • No past injury or illness
    83. 83. Patients With Chronic Pain • Higher rates of depression and anxiety. • Sleep disturbance and insomnia common. • Substance abuse highly prevalent in chronic pain population. • Drug-seeking behaviors • Chicken or egg? • Chronic pain may contribute to decreased physical activity. • Fear of making pain worse.
    84. 84. The Patient With Chronic Pain
    85. 85. Common Causes of Chronic Pain • Arthritis • Back Pain • Cancer • Chronic Fatigue Syndrome • Clinical depression • Fibromyalgia • Headache • Irritable Bowel Syndrome • Sciatica • Lumbar spinal stenosis and cervical spinal stenosis
    86. 86. Chronic Pain Treatmentsfrom National Institute of Neurological Disorders and Stroke • Medications • Opioids • Benzo’s • Anti-depressants • Anti-Epileptics • Acupuncture • Local electrical stimulation • Surgery • Placebos • Psychotherapy • Relaxation • Biofeedback
    87. 87. Chronic Pain and EMS • Patients with chronic pain call EMS for many reasons • Pain recently got worse • Pain recently changed or moved • Pain now accompanied by new swelling, heat or deformity • Patient hopes EMS can provide pain medications that MD cannot or will not (Pain contract)
    88. 88. EMS Treatment of Chronic Pain • The EMS provider should remember that chronic pain is still a medical disorder • Not all in their head • Not all patients with chronic pain are drug-seekers • Not all patients with chronic pain are “whiners” • Do not make light of their condition
    89. 89. Finishing up…. • Pain scale is a Vital Sign. • Pain has many causes, all real, just not all physical • Addressing all potential causes leads to more effective pain management. • Pain management should be a part of initial patient care for extremity injuries. • Waiting to “get to the ambulance” for pain management is outside the standard of care. Treat the “stable patient” where you find them. • Failure to give pain medication in the field may delay administration for an hour or more in the hospital—proximity to the hospital should not prevent medicating.
    90. 90. Questions?