Pain Management

2. Pain Management Consultant Professor : Dr Yekefallah SeyedehHedyehBanihashemi & MahtabSalehi Master students of critical care nursing (entrance Mehr 92) Automn 1392

3. objective • Explain the pain definition & its pathophysiology • Know different pain theories especially Gate-control • Describe different types of pain • Explain pain treatment (Drug & Nondrug) • Assess patient’s pain & know different assessment tools • Determine nursing process • Know geriatric & pediatric consideration

4. Pain It is an unpleasant sensory & emotional experience associated with actual or potential tissue damage .

5. Are these sentences true or false? 1. The best judges of the existence and severity of patient’s pain are the physicians and nurses caring for the patients . False

6. 2. Patients should not receive analgesic until the cause of pain is diagnosed. False

7. 3. Pain makes anxiety worse . True

8. 4. Patients who are knowledgable about opioid analgesics and who make regular efforts to obtain them are drug seeking (Addicted) False

9. 5. Critically ill patients , especially those who appear to be unconscious or have received a neuromuscular blocking agents , do feel pain and recall painfull episodes in ICU. True

10. 6. Patients with PTSD (Post Traumatic Stress Disorder) show low sensitivity to acute pain and rarely have chronic pain . False

11. Pain pathophysiology There are four basic processes involved in acute pain : • Transduction • Transmission • Perception • Modulation

12. C fibres Primary afferent fibres Small diameter Unmyelinated Slow conducting Pain quality Diffuse Dull Burning Aching Referred to as ‘slow’ or second’ pain • A-delta fibres Primary afferent fibres Large diameter Myelinated Fast conducting Pain quality Well-localised Sharp Stinging Pricking Referred to as ‘fast’ or ‘first’ pain

13. Transduction • Transduction begins when the free nerve endings (nociceptors) of C fibres and A-delta fibres of primary afferent neurones respond to noxious stimuli. Nociceptors are exposed to noxious stimuli when tissue damage and inflammation occurs as a result of, for example, trauma, surgery, inflammation, infection, and ischemia.

14. … transduction • The cause of stimulation may be internal, such as pressure exerted by a tumour or external, for example, a burn. This noxious stimulation causes a release of chemical mediators from the damaged cells including: prostaglandin bradykinin serotonin substance P potassium histamine

15. Transmission • The transmission process occurs in three stages. The pain impulse is transmitted: • from the site of transduction along the nociceptorfibres to the dorsal horn in the spinal cord; • from the spinal cord to the brain stem; • through connections between the thalamus, cortex and higher levels of the brain.

16. … transmission • In order for the pain impulses to be transmitted across the synaptic cleft , excitatory neurotransmitters are released , these neurotransmitters are: • adenosine triphosphate; • glutamate; • calcitonin gene-related peptide; • bradykinin; • nitrous oxide; • substance P.

17. Perception • Perception of pain is the end result of the neuronal activity of pain transmission and where pain becomes a conscious multidimensional experience. • The multidimensional experience of pain has affective-motivational, sensory-discriminative, emotional and behavioural components. • When the painful stimuli are transmitted to the brain stem and thalamus, multiple cortical areas are activated and responses are elicited.

18. … perception • The reticular system: - This is responsible for the autonomic and motor response to pain and for warning the individual to do something, for example, automatically removing a hand when it touches a hot saucepan. - It also has a role in the affective-motivational response to pain such as looking at and assessing the injury to the hand once it has been removed form the hot saucepan.

19. … peception • Limbic system This is responsible for the emotional and behavioural responses to pain for example, attention, mood, and motivation

20. … perception • Somatosensory cortex • This is involved with the perception and interpretation of sensations. It identifies the intensity, type and location of the pain sensation and relates the sensation to past experiences, memory and cognitive activities. • It identifies the nature of the stimulus before it triggers a response, for example, where the pain is, how strong it is and what it feels like.

21. Modulation • The modulation of pain involves changing or inhibiting transmission of pain impulses in the spinal cord. • The multiple, complex pathways involved in the modulation of pain are referred to as the descending modulatory pain pathways (DMPP) and these can lead to either an increase in the transmission of pain impulses (excitatory) or a decrease in transmission (inhibition). • Inhibitory neurotransmitters include: • endogenous opioids (enkephalins and endorphins); • serotonin (5-HT); • norepinephirine (noradrenalin); • gamma-aminobutyric acid (GABA); • neurotensin; • acetylcholine; • oxytocin.

22. Pain theories • Specificity theory • Pattern theory • Intensity theory • Gate control theory

23. Gate control theory • Proposed by Ronald Melzack and Patrick Wall during the early 1960s • Gate control theory suggests that the spinal cord contains a neurological "gate" that either blocks pain signals or allows them to continue on to the brain • Pain signals traveling via small nerve fibers are allowed to pass through, while signals sent by large nerve fibers are blocked. • Gate control theory is often used to explain phantom or chronic pain.

26. Phantom pain

27. Phantom pain • Phantom pain sensations are described as perceptions that an individual experiences relating to a limb or an organ that is not physically part of the body. • Limb loss is a result of either removal by amputation or congenital limb deficiency. • Sensations are recorded most frequently following the amputation of an arm or a leg, but may also occur following the removal of an internal organ .

28. … phantom pain There are various types of sensations that may be felt: • Sensations related to the phantom limb's posture, length and volume e.g. feeling that the phantom limb is behaving just like a normal limb like sitting with the knee bent or feeling that the phantom limb is as heavy as the other limb. • Sensations of movement (e.g. feeling that the phantom foot is moving). • Sensations of touch, temperature, pressure and itchiness. Many amputees report of feeling heat, tingling, itchiness, and pain.

29. The perception of phantom pain

31. Pathophysiology • mechanisms of phantom pain are often separated into peripheral, spinal, and central mechanisms. • Neuromas formed from injured nerve endings at the stump site are able to fire abnormal action potentials, and were historically thought to be the main cause of phantom limb pain. • Although stump neuromas contribute to phantom pains, they are not the sole cause. This is because patients with congenital limb deficiency can sometimes, although rarely, experience phantom pains.

32. Stump pain • Stump pain that occurs immediately after amputation is acute nociceptive pain and usually resolves after a few weeks as the wound heals. • Infection or wound dehiscence may prolong postoperative pain in some cases. • Stump pain can persist for much longer than the initial period of wound healing, lasting months or years, and occurs in 13--71%of cases.

33. Phantom pain • The precise incidence of phantom pain is not known. recent evidence suggests rates of approximately 50--78%. • Phantom pain normally occurs within the first week after amputation. • Phantom pain has been described in various terms (e.g.shooting, burning, cramping and aching) and is characteristically localized in the distal area of the phantom limb.

34. Phantom pain treatment It includes : • Pharmacological therapy • Noninvasive therapy • Minimally invasive therapy • Surgery

35. Pharmacological therapy • Antidepressants.Tricyclic antidepressants often can relieve the pain caused by damaged nerves. Examples include amitriptyline and nortriptyline (Pamelor). • Anticonvulsants. Epilepsy drugs — such as gabapentin (Gralise, Neurontin), pregabalin (Lyrica), and carbamazepine (Carbatrol, Tegretol) — are often used to treat nerve pain. They work by quieting damaged nerves to slow or prevent uncontrolled pain signals. • Narcotics.Opioid medications, such as codeine and morphine, may be an option for some people, they may help control phantom pain.

36. Noninvasive therapy • Nerve stimulation. In a procedure called transcutaneous electrical nerve stimulation (TENS) , a device sends a weak electrical current via adhesive patches on the skin near the area of pain. This may interrupt or mask pain signals, preventing them from reaching your brain.

37. Electric artificial limb. A type of artificial limb called a myoelectric prosthesis has motors controlled by electrical signals that occur during voluntary muscle activation in the remaining limb. Using a myoelectric prosthesis may reduce phantom pain.

38. Mirror box. This device contains mirrors that make it look like an amputated limb exists. The mirror box has two openings one for the intact limb and one for the stump. The person then performs symmetrical exercises, while watching the intact limb move and imagining that he or she is actually observing the missing limb moving. Studies have found that this exercise helps relieve phantom pain in a significant number of people.

39. Acupuncture. It's thought that acupuncture stimulates your central nervous system to release the body's natural pain-relieving endorphins. Acupuncture is generally considered safe when performed correctly.

40. Minimally invasive therapy • Injection. Sometimes injecting pain-killing medications local anesthetics, steroids or both into the stump can provide relief of phantom limb pain. • Spinal cord stimulation. Your doctor inserts tiny electrodes along your spinal cord. A small electrical current delivered to the spinal cord can sometimes relieve pain. • Intrathecal delivery system. This procedure allows medication to be delivered directly into the spinal fluid.

41. Surgical therapy • Brain stimulation. Deep brain stimulation and motor cortex stimulation are similar to spinal cord stimulation except that the current is delivered within the brain. A surgeon uses a magnetic resonance imaging (MRI) scan to position the electrodes correctly.

42. Stump revision or neurectomy. If phantom pain is triggered by nerve irritation in the stump, surgical resection or revision can sometimes be helpful. But cutting nerves also carries the risk of making the pain worse.

43. Newer approaches to relieve phantom pain • Virtual reality goggles The computer program for the goggles mirrors the person's intact limb, so it looks like there's been no amputation. The person then moves his or her virtual limb around to accomplish various tasks, such as batting away a ball hanging in midair. Although this technique has been tested on only a few people, it appears to help relieve phantom pain

44. Researchers at University of California, San Diego, reported results of a new study that found amputees find relief from phantom limb pain by simply watching someone else rub their hands together. • The researchers believe the act of watching another person rub their hands together activates the amputee’s brains cells, essentially fooling the brain into thinking the amputee’s missing hand is being massaged. 

46. THE EFFECT OF ACUPRESSURE ON PHANTOM PAIN IN CLIENT WITH EXTREMITIES AMPUTATION • Z. Pouresmail *, A. SaberiShaheedBeheshti University of Medical Sciences, Tehran, Iran • Analyzing statistical tests, indicates that acupressure treatment can decrease intensity of phantom pain (p < 0.0001) and decrease amount of medications (p < 0.005) and both of hypothesis were accepted.

47. Pulsed Radiofrequency of Lumbar Dorsal Root Ganglion for Chronic Postamputation Phantom Pain • FarnadImani 1*, Helen Gharaei 1, MehranRezvani 1 • Global clinical improvement was good in one patient, with a 40% decrease in pain on the visual analogue scale (VAS) in 6 months, and moderate in the second patient, with a 30% decrease in pain scores in 4 months. • PRF of the dorsal root ganglia at the L4 and L5 nerve roots may be an effective therapeutic option for patients with refractory phantom pain.

49. Phantom limb pain after amputation in diabetic patients does not differ from that after amputation in nondiabetic patients • There is a commonly held belief that diabetic amputees experience less phantom limb pain than nondiabetic amputees because of the effects of diabetic peripheral neuropathy • Participants with diabetes were further divided into those with long-duration diabetes (>10 years) and those with short-duration diabetes . • Our findings suggest that there is no large difference in the prevalence, characteristics, or intensity of PLP when comparing diabetic and nondiabetic amputees . • prevalence in DM group (82.0%) and the ND group (89.4%) (P = 0.391)