SELF – LEARNING MODULE ADDED NURSING COMPETENCY FOR MONITORING AND CARE OF THE PATIENT RECEIVING NEURAXIAL ANALGESIA. Originally developed by Susan Warman , BN., Helen Gourlay,BN /MN. ,and Janet Walker, BN. January 1997
Originally developed by Susan Warman, BN., Helen Gourlay,BN/MN. ,and Janet Walker, BN. January 1997
Revised Dec 2005 by Nancy Schuttenbeld -Acute Pain Nurse for RVH, Reviewed by Dr. Rick Chisholm, Anesthesiology, Marie Chase- Learning Services.
Pain TransmissionUnderstanding of the transmission of pain is essential to the management of pain. There are three main types of pain: Acute pain, cancer pain and chronic nonmalignant pain. Pain is also classified by pathophysiology as nociceptive pain (stimuli from somatic and visceral structures) and neuropathic pain (stimuli abnormally processed by the nervous system).Nociceptive pain is normal processing of stimuli that damages normal tissue or has the potential to do so, if prolonged. This pain is usually responsive to nonopioids and or opioids. Acute pain is mainly nociceptive and is classified as either somatic (referring to pain of the musculoskeletal system) or visceral pain (referring to pain arising from the body’s internal organs).Nociception is the term used to describe how pain becomes conscious. Four basic processes are involved: Transduction = The sensation of pain by cell damage or injury.Transmission = Occurs in the dorsal horn of the spinal cord (substance P is released here).Perception= This is how we interpret the pain (a conscious experience).Modulation= Refers to changing or inhibiting pain impulses. (response to pain) Substance “P” foun4. Modulation3. Perception2. Transmission1. Transductiond in the dorsal horn.Narcotics such as morphine are thought to bind to opiate receptors in the dorsal horn. This blocks substance P and as a result blocks the transmission of pain.When opiates are delivered into the epidural space the drug moves slowly across the meninges, through the CSF and finally to the opiate receptors in the dorsal horn – the pain relief results from the drug levels in the spinal cord.Delivering the narcotic to the opiate receptors in the spinal cord assists in decreasing the side effects that occur when using other routes of parenteral narcotics. The duration of action is longer as the narcotic must diffuse out of the CSF to the bloodstream and then be eliminated as usual by the liver and kidneys. Monitoring for LATE side effects should continue up to 12 hours post injection. Most of the late side effects you will see are thought to be due to spread through the CSF to the brain (rostral spread).Venous, CSF and epidural spaces lie within close proximity. If a bolus dose of a medication is inadvertently injected intravenously or intrathecally (CSF) the effects of the narcotic will be more profound.