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DR FATMA AL DAMMAS DR FATMA AL DAMMAS The management of pain is a multidisciplinary team effort involving physicians, psychologists, nurses, and physical therapists. Copyright © 2003 American Society of Anesthesiologists. All rights reserved Anesthesiologists are physicians and are experts in the diagnosis and treatment of acute and chronic pain disorders. Copyright © 2003 American Society of Anesthesiologists. All rights reserved Causes of Post-Operative Pain • • • • • • • • • incisional deep positional IV site tubes respiratory rehab surgical others skin and subcutaneous tissue cutting, coagulation, trauma bed sore, nerve compression & traction needle trauma, extravasation, venous irritation drains, nasogastric tube, ETT from ETT, coughing, deep breathing physiotherapy, movement, ambulation complication of surgery cast, dressing too tight, urinary retention CAUSES OF VARIATION IN ANALGESIC REQUIREMENTS • • • • • Site and type of surgery Age, gender Psychological factors Pharmacokinetic variability Pharmacodynamic variability Site and type of surgery • general upper abdominal surgery produces greater pain than lower abdominal surgery • operation on the richly innervated digits associated with severe pain. • The type of pain differ with different types of surgery. Age, gender and body weight • analgesic requirements of males and females are identical for similar types of surgery. • There is a reduction in analgesic requirements with advancing age. Psychological factors • The patient’s personality affects pain perception and response to analgesic drugs. • Patients with a less anxiety exhibit less postoperative pain and require smaller doses of opioid than patients who rate highly on anxiety scales. TREATMENT OF PAIN GOALS OF THERAPY • • • • • • Decrease the frequency and / or severity of the pain General sense of feeling better Increased level of activity Return to work Decreased health care utilization Elimination or reduction in medication usage Copyright © 2003 American Society of Anesthesiologists. All rights reserved Pain • Pain is subjective and difficult to quantify PAIN • An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage. ( International association of study of pain) CLASSIFICATION OF PAIN PAIN ACUTE SOMATIC SUPERFICIAL CHRONIC VISCERAL DEEP TRUE VISCERAL DE AFFERENTATION SYMPATHETICALLY PAIN MEDIATED PAIN TRUE PARIETAL REFERED VISCERAL REFERED PARIETAL TYPES OF PAIN According to duration Acute Chronic TYPES OF PAIN According to Pathophysiology • Nociceptive; Due to activation, sensitization of peripheral nociceptors. • Neuropathic: Due to injury or acquired abnormalities of peripheral OR central nervous system. TYPES OF PAIN According to Etiology • Post operative OR • cancer pain TYPES OF PAIN According to Type of the organ affected –Toothache –Earache –Headache –Low backache 4 PAIN PATHWAY 1.Transduction-changing of the noxious stimuli in sensory nerve ending to impulse. 2.Transmission-movement of impulse from site of transduction. 3.Perception –recognizing, defining and responding. 4.Modulation-involves activation of the descending pathway that exert inhibitory effect on pain transmission. 1 2 3 ACUTE PAIN • Caused by noxious stimulation due to injury, a disease process or abnormal function of muscle or viscera • It is nearly always nociceptive • Nociceptive pain serves to detect, localize and limit the tissue damage. TYPES OF ACUTE PAIN • Somatic OR • Visceral SOMATIC PAIN • Superficial OR • Deep SUPERFICIAL SOMATIC PAIN • Nociceptive input from skin, subcutaneous tissue and mucous membranes • Well localized and described as sharp, pricking, burning and throbbing DEEP SOMATIC PAIN • Arise from Muscles, Tendons and Bones • Dull, aching quality and is less well localized • Intensity and Duration of stimulus affects the degree of localization VISCERAL PAIN • Due to disease process, abnormal function of internal organ or its covering e.g Parietal pleura, Pericardium or Peritoneum SUBTYPES OF VISCERAL PAIN – True localized visceral pain – Localized parietal pain – Referred Visceral pain – Referred parietal pain TRUE VISCERAL PAIN • Dull, diffuse and in midline • Frequently associated with abnormal sympathetic activity causing nausea, vomiting, sweating and changes in heart rate and blood pressure. PARIETAL PAIN • Sharp, often described as stabbing sensation either localized to the area around the organ or referred to a distant site. PATTERNS OF REFERRED PAIN Lungs T2 – T6 Heart T1 –T4 Aorta T1 –L2 Esophagus T3 – T8 Pancreas & Spleen T5 –T10 Stomach, liver and gall bladder T6 –T9 Adrenals T6 – L1 Small intestine T6 – T9 Colon T10 – L1 Ureters T10 – T12 Uterus T11 – T12 Bladder and prostate S2 – S4 Urethra & Rectum S2 – S4 Kidneys, Ovaries & Testis T10 – L1 SYSTEMIC RESPONCES TO ACUTE PAIN Efferent limb of the pain pathway is • Sympathetic nervous system • Endocrine system. Cardiovascular effects Tachycardia Hypertension Increased systemic vascular resistance RESPIRATORY SYSTEM • • • • • Increased oxygen demand and consumption Increased minute volume Splinting and decreased chest excursion Atelactasis, increased shunting, hypoxemia Reduced vital capacity, retention of secretions and chest infection GASTROINTESTINAL AND URINARY EFFECTS • • • • • Increased sympathetic tone Decreased motility, ileus and urinary retention Hypersecretion of stomach Increased chance of aspiration Abdominal distension leads to decreased chest expansion ENDOCRINE EFFECTS • Increase secretion of Catecholamine, Cartisol and Glucagon • Decreased secretion of Insulin and testosterone HEMATOLOGICAL EFFECTS 1. Increased platelet adhesiveness 2. Reduced fibrinolysis and hypercoagulatability IMMUNE EFFECTS Leukocytosis Lymphopenia Depression of reticuloendothetial system GENERAL SENSE OF WELL-BEING • Anxiety • Sleep disturbances • Depression There are many different techniques,nonpharmacological &pharmacological , both regional and non-regional to provide post op analgesia. Nonpharmacologic Approaches to Relieve Pain and Prevent Suffering hydrotherapy intradermal water blocks movement and Positioning touch and massage acupuncture transcutaneous electrical nerve stimulation (TENS aromatherapy heat and cold music and audioanalgesia. J Midwifery Womens Health 49(6):489-504, 2004. © 2004 Elsevier Science, Inc. PHARMACOLEGICAL WHO Ladder An essential principle in using medications to manage pain is to individualize the regimen to the patient WHO analgesic guidelines • Oral medications whenever possible • Dose “by the clock” – but always have “as needed”medications for breakthrough pain • Titrate the dose • Use appropriate dosing intervals • Be aware of relative potencies • Treat side effects Pharmacological approach • Acetamenophen • NSAIDs • Tramal • Opioids • Adjuvents therapy – – – – – – – – Anticonvulsantants Antideperssants NMDA antagonists Muscle relaxants Clonidine Corticosteroids Local Anesthetics Sedatives Acetaminophen • • • • The most widely used analgesic Non acidic and a phenol derivative Readily crosses the BBB. Its action mainly in the CNS, where prostaglandin inhibition produces analgesia and antipyresis. • Its peripheral and anti-inflammatory effects are weak. Acetaminophen • Doses of 10 to 15 mg/kg every 4 hours up to a daily maximum of 100 mg/kg • For the treatment of mild to moderate pain. Perfalgan Making paracetamol (hydrophobic) soluble Use of hydrophilic ingredients (mannitol and disodium phosphate) Ensuring its stability in solution - By controlling hydrolysis Use of a pH buffer (disodium phosphate and sodium hydroxide) - By preventing oxidation Addition of cysteine hydrochloride Oxygen-free manufacturing process Perfalgan 1g indications Short-term treatment of moderate pain, especially following surgery Short-term treatment of fever Alone or in combination In adults or children over 33kg How to handle Perfalgan 1. Take the cap off 2. Link the bottle to a drip with an air intake 3. Hook the bottle with the built-in calliper How to infuse Perfalgan First administration in the operating theatre Frequency of administration: 15-minute infusion every 4 to 6 hours Dosages - Adolescents and adults weighing more than 50kg: 1 g / 4 times a day - Children weighing more than 33kg, adolescents and adults weighing less than 50kg: 15 mg/kg (4 times a day ) NSAIDs NSAIDs • The NSAIDs are weak organic acids (PKa3 to 5.5) • Act mainly in the periphery • Bind extensively to plasma albumin (95% to 99% bound) • Do not readily cross the BBB • Extensively metabolized by the liver • Have low renal clearance «10% . NSAIDs NSAIDs are powerful inhibitors of prostaglandin synthesis through their effect on cyclooxygenase (COX) The adverse effects of NSAIDs in surgical patients • • • • • • gastrointestinal hemorrhage renal dysfunction or failure hematoma formation asthma in susceptible individuals anaphylaxis decreased healing of gastrointestinal anastomoses Tramal® (Tramadol) is a centrally acting analgesic with opioid and non-opioid activity for moderate to severe pain associated with acute and chronic conditions Dual mode of action of Tramadol Two complementary mechanisms of action: Opioid action: weak µ-receptor agonist Monoaminergic action: weak, indirect 2-receptor agonist Tramal® presentations (I) Prolonged-release tablets 100 mg, 150 mg, 200 mg Ampoules Capsules Drops Soluble tablets Suppositories Adverse events (AEs) • Most common reported AEs: headache, nausea, vomiting, dizziness and somnolence Moore RA, McQuay HJ. Pain 1997 Opioids TERMINOLOGY • Opiates are drugs derived from opium, • Opioid applies to substances with morphine-like activity • Endorphin is endogenous opioid peptides. CLASSIFICATION OF OPIOIDS • There are alternative classifications Agonist A drug that, when bound to the receptor, stimulates the receptor to the maximum level; by definition the intrinsic, .activity of a full agomstis unity. Morphine Antagonist A drug that, when bound to the receptor, fails completely to produce any stimulation of that receptor; by definition, the intrinsic activity of a pure antagonist is zero. Naloxone Partial agonist A drug that, when bound to the receptor, stimulates the receptor to a level below the maximum level; by definition the intrinsic, . activity of a partIal agonist lies between zero and unity. Buprenorphine (partial mu agonist) Mixed agonistantagonist A drug that acts simultaneously on different subtypes, with the potential for agonist action on one or more subtypes and antagonist action on one Nalbuphine (partial mu or more subtypes agonist, kappa agonist, delta antagonist) Transdermal therapeutic systems Advantages – constant blood levels – long duration of effect – avoidance of the gastrointestinal tract (no first-pass effect) – high patient compliance Disadvantages – risk of dermal irritation MORPHINE • • • • Oldest ,safe . Water soluble , works longer. No upper limit to dose. Metabolized by liver and extra hepatic site ,excreted by kidney. • Metabolite M6G very potent. • Causes respiratory depression, nausea, vomiting,pruritus and urinary retention Demerol • • • • • Most commonly used opioid 10mg is equal to 1mg of morphine fat soluble therefore short duration of action. Metabolite nor meperidine is a potent CNS stimulant. Side effects same as other opioids. Therapeutic approaches Therapeutic approaches in side effects of opioid therapy Side-effect Incidence Tolerance First step Second step Constipation Ca. 95% - Laxatives Change the mode of administration Nausea/ vomiting Ca. 30% Anti-emetics Opioid rotation Sedation Ca. 20% Opioid rotation Application close to the spinal cord Pruritus Ca. 2% - Opioid rotation Antihistamines Hallucinations Ca. 1% - Opioid rotation Haloperidol Co Analgesics Classification – – – – – – – Anticonvulsantants Antideperssants Muscle relaxants Clonidine Corticosteroids Local Anesthetics Sedatives Methods of Acute Postoperaive Pain Relief Methods of Acute Postoperaive Pain Relief • • • • • • Intramuscular Intravenous - Intermittent Bolus Intravenous-Continuous Infusion Patient Control Analgesia (PCA) Epidural analgesia Peripheral Blocks POSTOPERATIVE PAIN MANAGEMENT POSTOPERATIVE PAIN MANAGEMENT • Pain management continues to be a challenge to anaesthetist . • PCA ; epidural and nerve block are advance in analgesia that may assist this challenge. • Post op Pain management can be evaluated in terms of its ability to meet 2 main goals: To relieve postoperative pain. To relieve patient of inhibition of respiratory movement without sedation. IMPORTANCE OF POSTOPERATIVE ANALGESIA • Pain relief is desirable not only for humane and moral reasons,but also because pain relief improves the patients physiological and psychological status Pain Assessment: the 6 N’s • 3. Number?: What is the severity of the pain? Visual analog scale Pain as bad as it could possibly be No pain Descriptive intensity scale No pain Mild pain Moderate pain Severe Worst possible pain pain Numerical intensity scale 0 1 2 3 4 5 6 7 8 9 10 11 of 16 Pain Intensity Rating Scales • Pain Faces Scale 0 2 4 6 8 10 No hurt Hurts just a little bit Hurts a little bit more Hurts even more Hurts a whole lot Hurts as much as you can imagine • Brief Pain Inventory Shade areas of worst pain Put an X on area that hurts most (Cleeland, 1991; Wong et al, 2001) Pre-emptive analgesia The administration of analgesic agents prior to an injury in order to prevent development of central nervous system hyperexcitability or sensitization PATIENT CONTROLLED ANALGESIA • PCA is based on the belief that patients are the best judges of their pain. • They should be allowed an active role in controlling their pain. PCA • PCA are modified infusion pumps that allow patient to self administer a small dose of opioid when pain is present , thus allowing patients to titrate their level of analgesia against the amount of pain they are experiencing. PCA • PCA is well tolerated. • Offer flexibility in dose size and dose interval in individual patients. • Therapeutic serum level can be reached relatively quickly because the drug is administered into the vascular system directly. PCA • Patient can secure an early therapeutic serum level with repeated doses titrated to individual pain needs. • A steady state plasma level occurs because the elimination of the drug from the plasma is balanced by the patients self administered drug injection. Relationship of mode of delivery of analgesia to serum analgesic level • IM and IV PCA PCA • PCA allows patient control over their pain and therefore gives greater satisfaction. • PCA also eliminates the lag time between pain sensation and administration of analgesia. PAIN CYCLE I.M PRN ANALGESIA PATIENT FEELS PAIN Sedation Drug Absorbed I.M Given Calls Nurse Nurse Screen Meds Prepared PAIN CYCLE I.M PRN ANALGESIA PATIENT FEELS PAIN Sedation Calls Nurse absorbed Nurse screen I.M Given Meds prepared BENEFITS • Decreased nursing time • Increased patient satisfaction. • Used in a variety of medical and post-op surgical conditions. • Decreased narcotic usage. • Decreased level of sedation. • Earlier ambulation. BENEFITS • • • • • Decreased overall pain scores reported by patients. Increased compliance to post op care. Less anxiety. More autonomy regarding pain control. Improved rest and sleep pattern PCA FEATURES. • Drug concentration. • Drug reservoir volume. • Demand dose-amount patient will receive each time patient self administer. • Delay(lockout)-period of time no drug is available to the demand button. • Basal-continuous infusion of drug/hour,is optional. DRUG CONCENTRATIONS • Morphine =1mg/1ml. (0.1 -0.2 mg/kg). • Tramadol =10mg/1ml. (1-2 mg/kg ). • Fentanyl = 10 mcg/1ml. (10 mcg/kg). • Demerol = 10mg/1ml. (1-2 mg/kg). Epidural Analgesia INSERTION OF EPIDURAL CATHETER • The site is dependent upon the area of pain • Fixing the catheter Incision Level Thoracic Upper abdo Lower abdo Pelvic Lower extremity T4-T6 T6-T8 T8-T10 T8-T10 L1-L4 MEDICATION COMMONLY USED • OPIOIDS-Fentanyl +Morphine (affect the pain transmission at the opioid receptors) • L.A.-Bupivacaine(marcaine) (inhibits the pain impulse transmission in the nerves with which it comes in contact) Epidural Analgesia • Mode of administration – intermittent opioid bolus – PCA opioid – continuous infusion - LA+opioid • Advantages – most effective analgesia – systemic effect of opioid minimal – pre-empty analgesia – reduce incidence of thromboembolism Epidural Analgesia - Side Effects • From the technique – – – – dural puncture epidural haematoma epidural abscess nerve root trauma • From LA – hypotension – paraesthesia – motor weakness • From opioid – delay resp depress – urinary retention – pruritus Caudal Anaesthesia Brachial Plexus Block IVRA (BIER’S BLOCK)