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ICU Pain Management. Bryan Sloane June 2009. Pain Management . Managing pain is especially important in critically ill and trauma patients. Pain form an injury or illness can increase blood pressure, heart rate, and increase blood glucose; all of which can lead to serious complications.
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ICU Pain Management Bryan Sloane June 2009
Pain Management • Managing pain is especially important in critically ill and trauma patients. Pain form an injury or illness can increase blood pressure, heart rate, and increase blood glucose; all of which can lead to serious complications. • Definition: Analgesic is a pain killer derives from Greek an- ("without") and algos ("pain")
How is pain measured? • A visual analog scale is used for conscious patients. The patient chooses a number between 1 and 10 for the amount of pain they are having, with 1 being the lowest amount of pain and 10 being the highest.
Pain Assessment cont. • Pain is measured for unconscious patients by observing their level of agitation and movement. Vial signs can also be an indication of pain levels if they exceed the patients baseline vitals for their injury/illness.
How is pain controlled • Medications like Analgesics, antidepressants, and antiseizue medications. • Acupuncture, Placebo, other alternative practices • Transcutaneous Electrical Nerve Stimulation (TENS) • Surgery, Physical and aquatic therapy, Psychological support
How pain works • Nociceptor Receptors in the skin and internal organs are sensitive to painful stimuli. The receptors are free nerve endings connected to small diameter myelinated A nerve fibers and unmyelinated C nerve fibers. When these receptors are activated, they send a signal to the spinal cord that is processed as pain.
Gate Control Theory • Patrick Wall and Ronald Melzack in 1965 • pain is a function of the balance between the information traveling into the spinal cord through large nerve fibers and information traveling into the spinal cord through small nerve fibers • Large nerve fibers carry non-nociceptive information and small nerve fibers carry nociceptive information. If the relative amount of activity is greater in large nerve fibers, there should be little or no pain. However, if there is more activity in small nerve fibers, then there will be pain.
Analgesic Medications • Most common are Non-steroidal anti-inflammatory (NSAIDS) • inhibit cyclooxygenases, leading to a decrease in prostaglandin production. This reduces pain and also inflammation • Opiates and morphinomimetics • Morphine, the standard of Opiate Pain Control
Morphine • Main effect is binding to and activating µ-opioid receptors in the Brain • Increase Dopamine production in neurons in the ventral tegmental area (VTA), which project to the nucleus accumbens (NA) • Very addictive, similar in molecular structure to Heroin
Molecular Similarities between Morphine and Heroin • Only difference is acetyl groups (Rx Drug on Left, illegal drug on right)
Fentanyl • potency is approximately 81 times that of morphine • Works via the same pathway • Both can be delivered by Patient Controlled Analgesia (PCA) when patient awake and alert. PCA consists of a self-activating infusion pump programmed to deliver a set number of pain medication in an hour.
Alternative Therapy • Acupuncture • 1. Stimulation of large diameter nerve fibers that inhibit pain • 2. Could be placebo effect. Causes release of endorphins • 3. Some types of acupuncture may stimulate small diameter nerve fibers and inhibit spinal cord pain mechanisms (opposite of gate theory)
Other Therapies • Hypnosis • 1. May activate the pain-inhibitory pathway from the brain to the spinal cord (not opiate pathway) • 2. May act somewhere in the brain to shift a patient's attention away from the pain. • PT • relieve pressure/compression on nerves/tissue through movement • Nitric Oxide Gas (NO) • Laughing gas, administered with oxygen, has potential in prehospital use, already used in other countries.
Sources • Chudler, Eric. "Pain." Neruoscience. Jan. 2009. Washington University. 8 June 2009. • Erdek, Michael, and Peter Pronovost. "Improving assessment and treatment of pain in the critically ill." Journal for Quality in Healthcare 16 (2004): 59-64. • Drugs.com