NSG 7404 Week 10 Lecture 2 PDF

NSG 7404 Week 10 Lecture 2 Weekly Topics/Objectives Definitions and Classification of Chronic Pain; AP&P Special Issues in Chronic Pain Evaluation of Patients Suffering from Chronic Pain Pain Syndromes and Interventions Selected Patho: Risk Factors for Acute Pain Transformation --> Chron...

NSG 7404 Week 10 Lecture 2 Weekly Topics/Objectives Definitions and Classification of Chronic Pain; AP&P Special Issues in Chronic Pain Evaluation of Patients Suffering from Chronic Pain Pain Syndromes and Interventions Selected Patho: Risk Factors for Acute Pain Transformation --> Chronic Pain, Other Pain Syndromes Pain Syndromes and Interventional/Medical Therapy ** Limited to what I selected from Ch. 47 in M&M ** Persistence of Acute Pain Risk Factors: CP After Surgery or Injury Overall estimates approximate CP after major surgery to have a prevalence of 20-50% Highest prevalence after traumatic injuries CP is one of the common complications of surgery Anesthetic techniques may reduce the incidence of CP after surgery Particularly opioid minimization and regional/neuraxial technique usage CP is cited as a complication from “minor” surgery as well Hernia repair = approximately 10 – 35% C-section = approximately 10 – 15% (highly variable intervals in literature) Most common long-term complication after inguinal hernia repair is chronic pain (Jenkins, 2010) Cited in studies after vasectomy & cosmetic breast surgery with a prevalence of approximately 15% Incidence of Persistent Postoperative Pain Persistent postoperative pain affects millions of patients each year Potential large contributor to CP burden in healthcare and to economic productivity Prevention of postoperative CP is now considered one of the most important areas of research in the perioperative care of patients CP ~ Preoperative Risk Stratification Preoperative depression Preop pain and anxiety/fear levels Especially high if preop pain > 1 month duration Repeat surgery, traumatic acute injury Surgical approach (level of invasiveness) Near or within a nerve plexus Large incision, significant degree of retraction Length of surgery Planned anesthetic technique Female gender Preoperative opioid exposure, especially chronic use Younger age in adult populations Genetic vulnerability (SNPs)…if known Lack of social support network CP ~ Pre-incisional Pain after surgery is a highly specific Risk Stratification entity: a combination of both an inflammatory response & a nociceptive overload response Peripheral and central neuronal sensitization contribute to both Both are related to the initial intensity of nociceptive input from incision, and any other periods of high-level tissue injury perioperatively High dose opioids, especially potent opioids** is a high-risk situation for development of OIH and STT sensitization It is our obligation to understand /prepare for effective analgesic efforts especially during the highest intensity periods for noxious stimuli CP ~ Postoperative Risk Stratification Poor analgesia, especially in the first 24 hours ** Overall (median) severity of pain over the first 5-7 days is more predictive for CP risk than any single max pain score Rad therapy to affected area Neurotoxic chemo treatment exposure Altered immune function (elevated inflammatory response) Depression/Anxiety/Social isolation Variable response to opioid therapy due gender differences or genetic vulnerability Gabapentin and Pregabalin* Great meds for pre-emptive analgesic regimens or for neuropathic pain Originally designed as anti-epileptic agents, still used for this as well Blocks VG Ca2+ channels to decrease NT release, neuronal excitability & transmission Stimulates endogenous descending inhibition of pain Inhibits descending facilitation of pain via specific serotonin receptors Inhibits certain inflammatory mediators Positively influences the affective response to pain stimuli Has potential for physical dependence and patients should be weaned off Can lead to seizures if suddenly discontinued after long course of therapy  Postoperative CP Risk Mitigation Effective anxiolysis preoperatively, effective analgesia preoperatively Cox inhibitors preop (?) and anti-inflammatory meds perioperatively No evidence for glucocorticoid use beyond nausea prophylaxis or stress dosing Regional or neuraxial (SAB/epidural) anesthetic techniques Parenteral local anesthetics (lidocaine) Multimodal analgesic regimen Continuous surgical wound local anesthetic infiltration (On-Q infusion, etc.) NMDA receptor antagonists (ketamine, N2O, dextromethorphan) Anticonvulsants: gabapentin and pregabalin (recall MOA?) Alpha2 agonists (clonidine and dexmedetomidine) parenteral, or as block adjuncts The ability of the surgical team to plan for and execute less invasive or altered techniques (more precise dissection to spare large nerves or plexuses) Further research efforts continue into other cellular or chemical targets Balanced, Preemptive Multimodal Analgesia Analgesics that act on distinct and varied pain pathway components, to increase efficacy and decrease undesired side effects Goal of preemptive analgesia is to prevent the induction of CNS plasticity Initiated prior to procedural trauma Modalities or their effects outlive the continued generation of noxious stimuli, or at least the most intense period of the same Better pre-emptive modalities modify noxious afferent input before cortical perception…. Best modalities modify/minimize noxious afferent input prior to transmission into the SC  Clinical Example… C-section Protocol Preop visit with family present, with full explanations Gabapentin 600 mg po preop; Bicitra 30 ml preop Zofran 4-8 mg IV once entering the OR during positioning, monitors being applied* SAB w/ 0.75% hyperbaric marcaine plus or minus IT narcotics or dexmedetomidine If epidural present and running, conversion to anesthetic vs. analgesic intervention Ofirmev 1000 mg IV after SAB level established, and q 6 hours postop x 24 hours Block supplementation with ketamine/propofol if needed for prolonged surgery Toradol 30 mg IV after case nearing completion, and q 6 hours postop x 24 hours TAP/QL block in the OR when case complete: 20 ml Ropivacaine 0.2% each side Meds for breakthrough postop pain typically included incremental dosing of narcotics, IV/PO G, Han J, Wang Y, Zheng J. Effects of prophylactic ondansetron on spinal anesthesia-induced hypotension: a meta-analysis. Int J Obstet Anesth. 2015;24(4):335-343. doi:10.1016/j.ijoa.20 Selected Pain Syndromes Brief Descriptions and Implications  Entrapment Syndromes Can involve sensory, motor or mixed nerves, wherever the nerves course through a narrow passage Genetic predisposition, micro- or microtrauma or adjacent inflammatory processes With sensory nerves, pain and numbness occurs distal to the entrapment Occasionally the pain can also be somewhat proximal to the entrapment level With motor nerves, entrapment produces muscle weakness to motor units innervated Occasionally motor nerve entrapment can also produce pain EMG/nerve conduction studies, or neural blockade* of involved nerve(s) are diagnostic Treated with analgesics, anti-inflammatory meds, plus or minus immobilization Some entrapments are commonly treated with surgical interventions Median nerve (carpal tunnel syndrome): Ulnar nerve (cubital tunnel) Some entrapments respond very well to physical therapy interventions Piriformis Syndrome (sciatic nerve compressed in sciatic notch) Carpal and Cubital Tunnel Release Myofascial Pain Syndromes Aching muscle pain, muscle spasm, weakness, stiffness; occasionally autonomic dysfunction can be associated with these syndromes Many patients have defined trigger points in several distinct areas : treated with massage, medication, ultrasound therapy, PT, trigger point injections Fibromyalgia Low Back Pain Degenerative Disc Disease Discogenic pain from nucleus pulposus herniation (90% occur at L4-5 or L5-S1) Radicular pain (usually unilateral) results from compression of nerve roots r/t herniated material Disc height loss  bone spur formation from vertebral body rims  spinal stenosis Best therapy for DDD in spine… ? (surgery, injections, multimodal therapy) ? ** Typical Presentation of Lumbar Radiculopathies Diabetic Neuropathy Major cause of M&M in diabetics: most common cause of neuropathic pain Can be generalized, symmetric, focal, or multifocal Can affect peripheral sensory or motor nerves Can affect cranial or autonomic nerves, as well as the enteric nervous system Autonomic involvement  CV issues: orthostatic hypotension, unpredictable HR variability GI involvement: delayed gastric emptying, and esophageal motility issues Peripheral polyneuropathy (most common neuropathic syndrome) Stocking and glove distribution Symmetric numbness, paresthesia, dysesthesia or pain Loss of proprioception & sensory dysfunction  injuries, gait problems Treatment options: improved glycemic control, NSAIDS of limited value; TCA plus anti-epileptic agents have shown some good efficacy Pain Syndromes (Sympathetic & SNS Independent) Complex Regional Pain Syndromes CRPS 1 (AKA Reflex Sympathetic Dystrophy): absence of a documented nerve injury CRPS 2 (AKA Causalgia): presence of a documented nerve injury Injury can be minor, although more common with crush injuries, fractures, surgery, severe sprains S/Sx/pathophysiology/interventions and treatment response similar in both Epidemiology: ~ 50K per year in the US, more common in females, childhood to adulthood age ranges Burning neuropathic pain with hyperalgesia/allodynia… intense and prolonged Autonomic signs: changes in sweating (sudomotor changes), piloerection, color, skin temperature, trophic* changes in the skin, hair or nails of involved areas Decreased strength and ROM of affected limbs Exacerbated by movement, and by factors that increase sympathetic tone (fear, anxiety, light, noise, touch) Frequently affects the nerves of the brachial plexus (median nerve especially) Frequently affects the tibial division of the sciatic nerve in the lower extremities Treatment of CRPS Some spontaneous recovery, and some https://www.ted.com/talks/elliot_krane_the_ permanent functional/psych disability mystery_of_chronic_pain?language=en Treated with sympathetic nerve blocks or IV regional sympatholytic blockade TENS unit/oral a blockade therapy (phenoxybenzamine, prazosin) Blocks intermittently continued until cured or response plateau reached Allows for PT which is key to recovery (active movement & desensitization Rx) Psychosocial treatment, biofeedback training 90% likelihood of cure if treatment initiated Please watch this TED talk to within 1 month of symptom onset understand this phenomenon much better!!! Headache Syndromes Tension Headache: squeezing band- Migraine Headache: long-lasting, debilitating, like constriction +/- neck muscle often unilateral or bi-frontal, throbbing severe HA tightness with photophobia, scotoma, N&V Rx: NSAIDs, acetaminophen, caffeine Can be preceded by an aura (transient neurological dysfunction) Sensory, motor, visual or olfactory Cluster Headache: unilateral and Complex patho: vasomotor, autonomic/serotonergic periorbital, multiple attacks in a day control systems, trigeminal nucleus dysfunction, over a period of weeks hormonal influences, muscular origins (?) Can even include a Horner syndrome- Abortive Rx: oxygen, triptans (5-HT agonists), ergot like presentation (ptosis, tearing, nasal alkaloids, IV lidocaine, SPG blocks stuffiness, red eye) Prophylaxis: B-blockers, calcium channel blockers, Rx: oxygen and sphenopalantine valproic acid, amitriptyline, Botox injections ganglion (SPG) blocks New class of medicines for prophylaxis targets Prophylaxis: lithium, corticosteroids, verapamil CGRP production and/or receptor antagonists Sphenopalantine Ganglion Block Sphenopalantine ganglion (SPG) is Indications for SPG Blockade an extracranial parasympathetic ganglion Migraine & Cluster HA, multimodal analgesia for sinus surgery, some forms of trigeminal neuralgia, post dural puncture headache AKA the pterygopalantine ganglion, or Contraindications the nasal ganglion Sensory (facial nerve/trigeminal nerve) Patient refusal, allergy to selected local anesthetics, and autonomic (both PSNS and SNS) anticoagulation Rx, history of facial trauma or input linkages to the trigeminal nerve facial/nasal surgery, suspected skull fracture with occur by traversing the SPG CSF leak, presence of infection Second order projections to secretory Complications control for mucous membranes of the oral and nasopharynx plus lacrimal Epistaxis, lacrimation, hypoesthesia of nearby glands tissues (nose, palate, pharynx) Also sends projections to branches of the Block failure, transient non-sustained relief meningeal and cerebral blood vessels SPG Blocks Transnasal Topical Approach The SPG lies posterior to the middle turbinate in the pterygopalantine fossa Supine position w/head tilted back or slight T-berg: use padded nasal swabs with hollow shaft posts (culture swab) Consider pre-procedure Afrin Soak swabs in high concentration of fast acting local anesthetics (LAs) 2-4% lidocaine, viscous is okay Insert until resistance is met in posterior NP Swabs need to remain in contact with posterior NP for 10-30 minutes Additional LA doses may be added (1-3 ml) into swab shaft Pain relief should occur within 5-10 minutes Transnasal Injection Approach Transoral Injection Approach Infrazygomatic Injection Approach (fluoro or CT guidance needed) Trigeminal Neuralgia (tic douloureux) Unilateral neuralgia usually in V2/V3 trigeminal nerve distribution Electric shock-like sensation, +/- facial spasm Often lasting seconds to minutes, occurring multiple times per day, Pain can be quite severe and unpredictable Known triggers may be found with careful H&P Entrapment or compression of nerve projections is typically the cause Can also be complication of Multiple Sclerosis Medical Rx: Tegretol, dilantin, baclofen Ablative Rx: glycerol injection, radiofrequency, balloon compression of the Gasserian (trigeminal) sensory ganglion Cancer Pain Multiple causes: cancer lesion, neural compression or infection, chemotherapy or radiation, pre-existing pain syndrome Oral analgesics, intrathecal delivery systems (opioids or other meds) IT Ziconotide: decreases the release of sP from presynaptic terminals in the dorsal SC Parenteral therapy for refractory pain or for patients who cannot take or absorb oral medications Plan can include interventional radiologic procedures  ganglionic blocks Analgesic plan should consist of scheduled regular multimodal analgesics with a well- planned breakthrough pain regimen Opioids Still a great option for short-term control of acute pain or palliative care Understanding relative strengths of opioid agents is imperative Dose minimization with the use of multimodal co-analgesics Prevention of tolerance/addiction Monitoring for OIH s/sx Interventional Therapies ~ Medications Interventional Therapies ~ Procedural Diagnostic & Therapeutic (U/S or fluoro) * Somatic Blocks Sympathetic Nerve Blocks Stellate Ganglion Block (head/neck arm/upper chest pain) Trigeminal Nerve Block Thoracic SNS Chain Block Paravertebral Nerve Blocks (pneumothorax complication risk is high) Facet Blocks Celiac Plexus Block (abdominal visceral S-I Joint pain, especially Ca) Pudendal Nerve Block Lumbar SNS Block Bier Block (IV Regional) Neuraxial E-stimulation or medication pumps may also be used Other Techniques Epidural Steroid Injections Radiofrequency Ablations/Cryoneurolysis Chemical Neurolysis Neuromodulation TENS SC Stimulation Peripheral Nerve Stimulation ** Deep Brain Stimulation Vertebral Augmentation (Kyphoplasty) Radical Treatment Options (FYI only- not for exam) Ketamine Coma for Refractory Chronic Pain https://painopolis.com/ketamine-coma-therapy-for-rsd- crps/ https://www.sciencedirect.com/science/article/pii/S088 7617707001230 https://www.cureus.com/articles/69692-use-of-ketamin e-infusions-for-treatment-of-complex-regional-pain-syn drome-a-systematic-review https://www.ncbi.nlm.nih.gov/pmc/articles/PMC399284 0/ Interdisciplinary Modalities/Team Members Therapeutic/diagnostic blocks Physical Therapy Anesthesia or IR Occupational Therapy provider Acupuncture/Massage Therapy Pharmacologic Rx Psychological treatment Intrathecal drug Rx Cognitive Rx, biofeedback, relaxation training E-stim (TENS and SC stim) Minimally invasive spinal Trigger point injections procedures Epidural steroids/LA Botulinum toxin injections Social work consult http://www.aafp.org/afp/20000301/1331.html What matters to anesthesia?  Know pre-existent pain and anxiety levels & Rx  Continue baseline meds for CP where possible  Account for any unusual pathology or procedural risks for acute, poorly controlled pain  Understand the procedural periods of high- level noxious stimulus generation and PLAN for those  Plan for multimodal and multi-technique co- analgesics and pre-emptive temperance of pain Questions? Grateful Memories… Thank you!!