Pain Management in the Emergency DepartmentJordan B. Barnett, MD FACEP

Associate Director

Department of Emergency Medicine

Northeastern Hospital/Temple University Hospital System

Overview

• Excess of 60% of all Emergency Department patients present with conditions associated with Pain

• In adequate analgesia frequent complaint in the Emergency Department

• Agency for Health Care Policy and Research Guidelines for acute pain management = guide

Definitions

• Pain: noxious sensation transmitted by specialized nervous structures to the brain where its perception is modulated by cognition and emotion

• Analgesia: Relief of perception of pain without production of a sedated state

• Anxiolysis: Reduction of apprehension without Altered Mental Status

More Definitions• Neurolepsis: Quiescence, indifference to

surroundings, reduced motor activity

• Dissociation: Amnesia, analgesia, sedation and maintenance of muscle tone (ketamine)

• Sedation: Controlled reduction of environmental awareness

• General Anesthesia: presence of sensory, mental, reflex and motor blockade and concurrent loss of all protective reflexes

Experience of Pain

• Determined by medical condition

• developmental level

• emotional and cognitive state

• personal concerns

• family issues and attitudes

• culture

• environment

Cornerstone of Pain Management

• Psychological and Physical aspects need to be address by both pharmacological and non pharmacological modalities

How to Medicate?

• Oral - limited in the ER because emergency operative often mandate NPO status and GI absorption can be poor due to underlying condition

• Repeated intramuscular doses of narcotic anaglesia is only indicated in sickle cell patients

• IV, Regional, topical

Pathophysiology of Pain

• Mediators of inflammation

• Modulated by neurocognitive factors and emotional experience

• Peripheral pain system (nociceptors, C fibers, A-delta fibers, free nerve endings)

• Substance P, Neurokinin A, and calcitonin gene-related peptide that are coreleased with glutamate within the spinal cord

More Pathophysiology (sorry!)

• Dorsal horn of spinal cord (eg. Dorsal root ganglion, inhibitory interneurons, and ascending pain tracts) integrates and modulates pain and other sensory stimuli

• Supraspinal centers (eg. Hypothalmic centers, thalamic nuclei, the limbic and reticular activating systems) integrate and process pain information.

Assessment and Reassessment of Pain

• Location, quality severity

• Pain is dynamic - reassess

• Awake, cooperative patient versus those who cannot communicate.

• Cognitively impaired, psychotic, elderly

• Cultural background

Pediatric Pain Evaluation

• Age-appropriate

• Developmentally specific techniques

• Involvement of parents or caregiver

Elderly

• Visual , hearing, motor, and cognitive impairments = barriers

Ethnicity

• Different cultural concepts of pain and on the characteristics of culturally appropriate pain-related behaviors

• Interplay between the ethnicity of patient and physician

Gender Related Issues

• Women are more likely to express pain and to seek treatment

• Physicians are more likely to underestimate and undertreat pain in female patients.

Approaches to Pain Assessment

• Non-Self Report Measurement (Respiratory and cardiovascular changes as well as changes in expression and movements)

• Self-Report Measurement (Numerical or adjective ratings and visual analogue scales)

Pain Assessment Tools

• Self report tools mainstay of pain assessment

• Adjective rating scale (simple, descriptive pain intensity scale presented graphically or verbally as linear list of pain descriptors)

• Numerical Rating Scale (ie. Cardiac pain assessment from 0-10)

• Visual Analogue Scale

Modalities of Pain Management

• Systemic, regional, local

• Nonpharmacologic-cognitive-behavioral

Pharmacologic Agents

• NSAIDS for mild pain

• Systemic opiods and/or NSAIDS for Moderate to severe pain

• Local or regional neural blockade helps minimize use of narcotic agents

Nonopiods

• Acetaminophen (paracetamol) for mild to moderate pain

• Enhanced when it is combined with codeine

• Not effect platelet aggregation

• Not antiinflammatory

• Hepatotoxic

NSAIDS

• Aspirin, Naproxen, Indomethacin, Ibuprofen, Ketorolac

• Decrease levels of inflammatory mediators

• Do not cause sedation or respiratory depression

• No interference with bowel or bladder function

NSAID Adverse Side Effects

• Platelet dysfunction

• Impaired coagulation

• Gastrointestinal irritation

• bleeding

• Use with care if thrombocytopenia, coagulopathies GERD

• Acute Renal failure possible

Opioid Agents

• Moderate to severe acute pain

• Response variable and dependant on age, body mass, previous or chorinic exposure to opioids

• No real difference in efficacy between the phenathrene derivatives (morphine) vs phenylpiperidieine (meperidine) and diphenylheptane (methadone)

Routes of Opiate Administration• Codeine Hydromorphone, oxycodone,

Morphine, and meperidine can be administerd orally (fentanyl Lollipops!)

• Codeine can be given orally and intramuscularly. IV dangerous

• Opiates combined with anxiolytic as an adjunct which provides pain relief at lower doses

• Transdermal patches

Narcotic Side Effects

• Confusion

• Respiratory Depression

• Hypotension

• Urinary Retention

• Pruritus

Other Agents

• Ketamine and nitrous oxide used widely for analgesic therapy

• Ketamine, a phenylcyclidine derivative produces analgesia and dissociative anesthesia

• Nitrous oxide is a fast onset short acting analgesic for brief minor procedures

Choosing a Route to Administer a Pharmacologic Agent

• Oral, rectal, intravenous, intramuscularly transmucosally, transdermally, inhalation, epidural

• IV versus intermittent IM injections

• IM injections are painful, and may deter patients from requesting medication

• Oral administration is convenient and inexpensive

Analgesic Dosage, Precautions and Comorbidity

• Titrate opiods to desired effect. Respiratory depression and hypotension possible side effects

• Relative potency tables

• Use cautiously if AMS, hemodynamic instability, respiratory dysfunction, or multisystem trauma.

Analgesic Dosage, Precautions and Comorbidity continued

• Extremes of age at risk for inadequate and pharmacotherapy complications

• Elderly at risk for drug-drug interactions

• Drug-disease interactions

• Altered Hepatic and Renal functions

• Patients with respiratory insufficency and COPD, cystic fibrosis, NMD

• MAOIs and demerol, TCAs with morphine

Cognitive-Behavioral and Physical Therapies for Analgesia

and Anxiolysis

• Heat and Cold application

• Immobilization and elevation

• Reassurance, explanation, relaxation

• Music, psychoprophylaxis, biofeedback, guided imagery, hypnosis, distraction

• TENS, acupuncture, electroacupressure.

Specific Situations

• Situations where management approach is complex or controversial

• Abdominal Pain: withholding analgesics in the setting of abdominal pain

• Migraine: Wide range of drugs

Disposition

• Inpatient vs outpatient

• Safety of discharging patients home on narcotics with conditions necessitating acute pain management is dependent on the precautions of a disease process which could be masked by the medications. Knowledge of the underlying pathologic diagnosis and home environment.

Local Anesthesia

• Local

• Regional

Local Anesthetic Agents

• Las are all synthetic drugs derived from cocaine

• Hydrophillic and hydrophobic region and a amide or ester linkage

• Las are weak bases

• Amides mostly used (lidocaine, bupicacaine)

LAs mechanism

• Decrease the rate and degree of depolarization and repolarization, decrease conduction velocity and prolong the refractory period of the neural action potential.

• Las bind to receptor sites on the voltage gated sodium channels

• Lipid solubility and pKa

Additives for Local Anesthetics

• Buffering: Increases the amount of uncharged drug available and decreases pain of infiltration.

• Epinephrine: longer duration of anesthesia, provides wound hemostatsis and lowers systemic absorption. Increases pain of infiltration. Not to be used in end-arterial fields

Toxicity of Local Anesthetics

• Determined by total dose and mode delivered

• Systemic Uptake

• Amide more common then esther for Toxicity

• Patients with atypical plasma cholinesterase

• Accidental venous injection

Serious Toxicity

• Usually involves CNS or cardiovascular

• Results in CNS from combination of central excitatory and depressant activity of Local Anesthetic ranging from perioral tingling and numbness to confusion, seizure and coma

• Cardiovascular relates to Sodium blockade and resultant myocardial depression

True allergic reactions

• Rare

• Due to metabolite para-aminobenzoic acid for esthers and the perservative methylparaben

• Esters more associated with allergic reactions than amides

• If allergy history, use perservative free agent from other class

Specific Agents

• Lidocaine = amide. Commonly used in ED. Decreased metabolism with hepatic failure or CHF

• Bupivacaine - Amide. Longer duration. Cardiotoxic

Topical Anesthetics

• TAC

• EMLA

• LET

• Viscous Lidocaine (stomatitis)

Refrigerant Anesthetic Sprays

• Ethyl Chloride

• Fluori-Methane

• Both only last 30 seconds to 1 minute with superficial anesthesia only

• Skin Ulceration possible from “frostbite”

• Can’t be used on mucosa

Novel Topical Techniques and Agents

• Jet Injector: Compressed air high-pressure jet injectors available to deliver Local Anesthetic agents both in liquid and powder form through epidermis in needle-less fashion

• Iontophoresis: Needleless system. Burning sensation under adhesive electrical pad

• Capsaicin

Regional Procedures

• Nerve Blocks

• Hematoma Blocks

Principles of Conscious Sedation

• Indicated for treatment of severe pain, attenuation of the pain and anxiety associated with procedures, rapid tranquilization, and the need to perform a diagnostic procedure

• Agents used have a narrow therapeutic index

• Airway management and monitoring

Equipment Necessary for Conscious Sedation

• High flow oxygen source

• suction source with large bore catheters

• vascular access equipment

• airway management equipment

• monitoring equipment

• resuscitation drugs

• Reversal Agents

• Adequate staff for monitoring and documentation

Drugs Commonly Used in Conscious Sedation

• Analgesics: Opiods most common. (morphine codeine/meperidine, fentanyl, sufentanil and alfentanil. Strength referenced against morphine. (Mu receptors)

• Anxiolytics: Benzodiazepines (GABA). Versed commonly used.

Anesthetics

• Propofol: Don’t use if egg allergic! Rapid onset and resolution (5-10 min). Cardiovascular depression.

• Ketamine: Dissociative. Emergence reactions (typical in females, over 16, normally dream, with personality disorders). Attenuate with benzos

Adjunctive Agents

• Antiemetic agents are useful in the treatment of nausea and vomiting accompanying opiod therapy.

Antidotal Agents

• Naloxone

• Flumazenil

Discharge• Vital signs stable for at least a half hour

• No evidence of respiratory distress

• Minimal or no nausea, vomiting, or dizziness

• Alter, oriented and able to retain information

• Able to take fluid and medications by mouth

• Ambulation consistent with preprocedure status

JCAHO

• Standard specifies that a uniform standard of care must be provided throughout the accredited institution

• Airway protection

• Guidelines from ACEP and ASA

Management of Patients with Chronic Pain

• Definition: Painful condition that lasts longer than 3 month

• Lasts longer than the reasonable time for an injury to heal or a month beyond the usual course of an acute disease

Types of Chronic Pain

• 1) Pain persisting beyond the normal healing time for a disease or injury

• 2) Pain relating to a chronic degernative disease or persistent neurologic condition

• 3) Cancer related pain

• 4) Pain that emerges or persists without an identifiable cause

Chronic Pain Syndromes

• Myofascial headaches

• Transformed migraine headaches

• fibromyalgia

• Myofascial chest pain

• back pain

• postherpetic neuralgia

• phantom limb pain

Epidemiology

• Affects one third of population at least once during a patient’s lifetime

• 80-90 billion dollars in health care payments and lawsuit settlements annually

• Those who seek medical attention are less physically active, experience more social alienation and more psychologic distress than those who do not seek attention

Causes

• A chronic pathologic process in the musculoskeletal or vascular system

• A chronic pathologic process in one of the organ systems

• a prolonged dysfunction in the peripheral or central nervous system

• a psychological or environmental disorder

Pathophysiology

• Nociceptive pain is associated with ongoing tissue damage

• Neuropathic pain is associated with nervous system dysfunction in the absence of ongoing tissue damage

• Psychogenic pain has no identifiable cause

Nociceptive pain

• Stimulation of nociceptors in tissues or organs by noxious mechanical thermal or chemical stimuli

• Chemical mediators (bradykinins and prostaglandins)

• Examples include cancer pain, pancreatitis

Neuropathic Pain

• Disease of the central or peripheral nervous system

• Examples include causalgia, postherpetic neuralgia, phantom limb pain

• Responds poorly to analgesics

Psychogenic Pain

• Responds poorly to common analgesics, including narcotics

• Diagnosis of exclusion

• Difficult to establish in the ED

Psychological Characteristics of Chronic Pain Patients

• Drugs: Misuse Narcotics or other meds

• Doctors: Doctor shop

• Dysfunction: Bodily impairment related to the physical and emotional factors

• Dysability: Inability to work

• Dependance: Loss of Self Reliance

• Dramatization: Exaggeration, acting out

• Depression: Despair and Negative attitudes

Substance abuse and Chronic Pain Patients

• 12-24% of patients referred to chronic pain clinics meet DSM III-R criteria for active substance abuse disorder

• Drug Detoxification is often first step in therapeutic plan for new patients referred to pain clinic

Objective Evidence Of Chronic Pain

• Muscle atrophy in the distribution of pain due to disuse

• Skin Temperature changes due to the effects of sympathetic nervous system after disuse

• Trigger points

• These findings do not have to be present

Myofascial Headaches and Transformed Migraine

• Myofascial headache is a variant of tension headache. Presence of trigger points on the scalp. Constant squeezing pain.

• Nausea, vomiting, neck pain may be present

• Transformed migraine: variant of classic migraine which transforms over time into a chronic pain syndrome

Fibromyalgia and Chronic Myofascial Chest Pain

• Classified by American College of Rheumatology as the presence of 11 of 18 specific tender points, non restorative sleep, muscle stiffness, and generalized aching pain lasting longer than 3 months

• Chromic Myofascial chest pain is classically a dull, constant pain associated with trigger points on the chest wall.

Back Pain

• Chronic back pain syndromes divided into myofascial or muscular, articular, and neurogenic types.

Complex Regional Pain

• Complex regional pain type I = reflex sympathetic dystrophy

• Complex regional pain type II- causalgia.

• These disorder 2 weeks or more after injury. Type I occurs because of prolonged immobilization or disuse. Type II occurs because of nerve injury

Post Herpetic Neuralgia

• Follows course of acute episode of herpes zoster.

• Hypersthesia in dermatome

• Pigmentation changes

Phantom Limb Pain

• Usually if pain in extremity before amputation

• Failure to respond to treatment including narcotics is common

Treatment• Opiate use only temporarily relieves the

pain sensations.

• With the exception of CA, the use of narcotics is controversial

• Antidepressants are frequently used used for management of chronic pain. They enhance endogenous inhibitory mechanisms

• Anticonvulsants used for neuropathic pain.

• Muscle relaxants, such as cyclobenzaprine

• Tramadol

Chronic Pain in the Elderly

• Frequent complaint

• Higher complication rates of meds in the elderly

• NSAIDS GI bleeding

• Opiods Sedation/constipation

Management of Patients with Drug Seeking Behavior

• 10 % of patients seeking treatment for drug addiction identify a prescription drug as the principle drug of abuse

• Chronic pain

• Drug addict

• Hustler

• Patients may move from chronic pain patient to addict to hustler as social support deteriorates

Epidemiology

• A study conducted in Portland found that drug seeking patients presented to the ED 12.6 times per year, visited 4.1 different hospitals, and used 2.2 different aliases. Patients who were refused narcotics at one facility were successful 93 percent of the time at another and were later successful at obtaining narcotics at the same facility 71%

COMMON COMPLAINTS

• Back pain,

• Headache, extremity pain

• Dental pain

• Panic Disorder

• Lost prescription

• Falsifying hematuria

Diagnosis

• Medical record

• Suspected but often can’t be confirmed

• Card file violates patient-physician confidentiality

Legal Implications

• DEA licenses physicians to administer controlled substances

• Illegal for patients to forge or alter prescriptions

• In some states concealing previous or recent prescriptions for narcotics when requesting narcotics from doc is illegal

Treatment and Disposition

• Refuse controlled substance

• Referral for counseling

• When confronted, many drug-seeking patients become abusive.

• Documentation in the chart

• If informed of forged scripts, call police

• ANY QUESTIONS?