pain mangement lecture for 3rd year mbbs

Pain control and postoperative analgesia

DR.NADIR MEHMOOD

Asst professor

Department ofSurgery, RMC

Objectives• Define pain and its types.• Explain the physiology of pain• Explain pain as the “fifth vital sign”• Enumerate factors influencing pain• Enlist pain control strategies• Elaborate rules for pharmacotherapy• Introduce some pharmacological approaches to treating

pain. • Algorithms for pain management• Describe nursing interventions for pain control• Enumerate complementary (non pharmacological

therapies used to control pain)

“Pain is a Sensory and Emotional experience,

associated with actual or potential tissue

damage or described in terms of such

damage”

(IASP)

Definition of pain?

Pain Types• NOCICEPTIVE PAIN

– results from ongoing activation of mechanical, thermal, or chemical nociceptors

– typically opioid-responsive– eg. pain related to mechanical instability

• NEUROPATHIC PAIN

– spontaneous or evoked pain that occurs in the absence of ongoing tissue damage,Dysfunction of the nervous system

– Abnormality in the processing of sensations– Associated with medical conditions rather than tissue damage

– typically opioid-resistant***– eg. pain secondary to nerve root injury

• Phantom Pain

Phantom Pain

• Occurs after the loss of a body part from amputation

• Patient “feels” pain in the amputated part for years after the amputation has occurred

• May be controlled

Accessed 11 February 2009 fromhttp://www.pc.rhul.ac.uk/staff/J.Zanker/PS1061/L6/phantom.gif

Time-based classification of pain

• Acute: short-term; usually due to nociception (tissue damage); resolves with healing.

• In back pain, Acute = < 4 wks Sub-acute = 4-12 weeks

Chronic = > 12 weeks• Chronic pain: pain lasting > 3-6 months

• Persisting pain (NHMRC: acute pain guidelines)

“pain is whatever the experiencing person says it is,

existing whenever he says it does.” (McCaffery & Pasero, 1989).

“It is not the responsibility of clients to prove that they are in pain; it is the physician’s responsibility to believe them.” (Crisp & Taylor, 2005).

Factors Influencing Pain• Age• Gender• Culture• Meaning of pain• Attention• Anxiety• Fatigue• Previous experience• Coping style• Family and social support

Causes of Acute Pain Post-operative

Burns

Trauma

Infective / Inflammatory conditions

Ischaemic pain

Visceral pain

Obstetric - Labor

Causes of Post-Operative Pain

Incisional skin and subcutaneous tissue Deep cutting, coagulation, trauma Positional nerve compression, traction & bed sore. IV site needle trauma, extravasation, venous irritation Tubes drains, nasogastric tube, ETT Respiratory from ETT, coughing, deep breathing Rehab physiotherapy, movement, ambulation Surgical complication of surgery Others cast, dressing too tight, urinary retention

Causes of Chronic Pain

Cancer pain Cancer related From cancer therapy Cancer unrelated

Non-cancer Nociceptive Neuropathic Idiopathic

Basics of Pain Management

• 1st step: is the good pain assessment.

• Pain medications must be taken:

when the pain is first perceived.

• Doses of opioids are increased:

with the patient’s report of pain

• Adjuvant medications are used for:

opioid non-responsive & neuropathic pain.

• Non-pharmacologic approaches are always a part of any pain management protocol.

The “Costs” of Uncontrolled Pain Stress response Hypothalamo-Pituitary-Adrenal axis:

Disturbed cytokine cascade. Impairment of immune function. Increased catabolism. Negative nitrogen balance.

Pain Chronicity. Cardiovascular Respiratory GIT Neuro-psychiatric Impairment of mobility, Gait disturbances.

Physiological effects of Pain• Increased catabolic demands: poor wound healing,

weakness, muscle breakdown• Decreased limb movement: increased risk of DVT/PE• Respiratory effects: shallow breathing, tachypnea,

cough suppression increasing risk of pneumonia and atelectasis

• Increased sodium and water retention (renal)• Decreased gastrointestinal mobility• Tachycardia and elevated blood pressure

Psychological effects of Pain

• Negative emotions: anxiety, depression• Sleep deprivation• Existential suffering: may lead to patients

seeking active end of life.

Immunological effects of Pain

• Decrease natural killer cell counts• Effects on other lymphocytes not yet defined.

The ‘fifth’ Vital Sign

• Assessed in all patients

• Patient/client right to appropriate assessment and management of pain

Acute Pain Management

Goal

• To provide patients with a level of pain control that allows them to actively participate in recovery– This level will be individual to each patient

• To minimize nausea and vomiting• To minimize other side effects of analgesics– Sedation– Ileus– Weakness– Hypotension

Why all this is vital??

• Pain is a miserable experience• Pain increases sympathetic output– Increases myocardial oxygen demand– Increases BP, HR

• Pain limits mobility– Increases risk for DVT/PE– Increases risk for pneumonia, atelectasis

secondary to splinting

Principles of Assessment

• Assess and reassess• Use methods appropriate to cognitive status and context• Assess intensity, relief, mood, and side effects• Use verbal report whenever possible• Document in a visible place• Expect accountability• Include the family

Assessment

• Location• Intensity• Onset • Duration• Radiation• Exacerbation• Alleviation

Good assessment = Successful management

Pain Assessment

N

R

S

Pain Assessment Tools

• In Adults: Self Report Measurement Scales, such as Numerical Scales

Pain Assessment Tools

• In Pediatric Patients:– Physiologic and Behavioral Indicators of

Pain ( Infants, Toddlers, Nonverbal or Critically Ill Children)

– Face Scale (Age 3-10 yrs)– Visual Analogue Scales (Age 10-18)

• Subjective:• Pain Scores:

• Unidimentional Acute pain• VRS, VAS & NRS.• Facial expression.

• Multidimentional Chronic pain• McGill & Pain Inventory.

• Objective:– Behavioral: refusal to move, cough & deep breath– Physiological: PR, RR, ABP, sweatiness & dilated pupils– Neuro-endocrinal: RBS, Stress hormones

Pain Assessment

Numeric Rating Scale (NRS)

Visual Analogue Scale (VAS)

0 10

Pain Scores

Wong-Baker “Faces Scale”

Verbal scale

NoPain

Mild ModerateSeverePain

–Pharmacotherapy– Anesthetic approaches– Implantable devices– Neurostimulation approaches– Alternative approaches– Surgical approaches– Rehabilitative approaches– Lifestyle changes– Psychological approaches

Pain Control Strategies

Drug Strategies• Non Opioid Analgesics:– NSAA– NSAIDs

• Non-selective COX inhibitors• Selective COX-2 inhibitors

• Opioids– Weak Opioids.– Strong opioids.– Mixed agonist – antagonists

• Adjuvants– Antidepressants– Anticonvulsants– Substance P inhibitors– NMDA (N-methyl-D-aspartate receptor) inhibitors– LA– Drugs for Headache– Drugs for Bone pain– Others .

• Alternative medicine:– Acupuncture– TENS– Cupping– Chiropractice

• Physical Therapy– ice, heat, massage

• Exercise• Psychological therapy

– Cognitive-behavioral therapy– Relaxation techniques– Biofeedback– Hypnosis

Non-Drug Strategies

Routes of Administration

• PO• PR• IV • IM• Transdermal• Transmucosal• Epidural• Intrathecal

WHO step Ladder

1 mild

2 moderate

3 severe

Morphine

Hydromorphone

Methadone

Pethidine

Fentanyl

Oxycodone

± Adjuvants

Codeine

Hydrocodone

Oxycodone

Dihydrocodeine

Tramadol

± Adjuvants

ASA

Acetaminophen

NSAIDs

± Adjuvants

Pain

Step 1±Nonopioid± Adjuvant

Pain persisting or increasing

Step 2Opioid for mild to moderate pain

±Nonopioid ± Adjuvant

Pain persisting or increasing

Pain persisting or increasing

Step 3Opioid for moderate to severe pain

±Nonopioid ±Adjuvant

Invasive treatments

Opioid Delivery

Quality of Life

Modified WHO Analgesic Ladder

Proposed 4th Step

The WHOLadder

Deer, et al., 1999

How do we do it?

• Multimodal analgesia: Several analgesics with different mechanisms of action, each working at different sites in the nervous system

OPIOIDS Efficacy is limited by Side-Effects

• The harder we “push” with single mode analgesia, the greater the degree of side-effects

Analgesia

Side-effects

Multimodal Analgesia• Lower doses of each drug can be used therefore

minimizing side effects• With the multimodal analgesic approach there is additive

or even synergistic analgesia, while the side-effects profiles are different and of small degree (Pasero & Stannard, 2012).

Analgesia

Side-effects

Systemic Analgesia

• Opioids– Potent analgesics– Drug of choice for moderate to severe pain– Unfortunately, they are often the only drug

ordered– Side effects:

Epidural Infusions

• Used for major surgery ie. Oncologic surgery, thoracotomy

• Ideally placed pre-operatively and used in combination with a GA for surgery and continued ~ 2 days

• Usually patient is tolerating diet and ambulation to chair when epidural is D/C

• Advantages:

– Patients can titrate their own analgesia

– Improved:• Pain relief• Pulmonary function.

– Decreased:• Total daily dose.• Over sedation.• Postoperative complications.

Routes of Administrations - PCA

Miscellaneous Adjuvant Analgesics

• Pamidronate (Aredia)• Zoledronic acid (Zometa)• Strontium-89 (Metastron)• Calcitonin (Calcimar) Not in cancer ? arthritis• Capsaicin (Zostrix) scheduled in neuropathic pain• Clonidine (Catapres) all forms• Cannabinoid (Marinol)

Analgesics for Neuropathic Pain• Tricyclic antidepressants

– nortriptaline (1st choice)• Anticonvulsants

– Gabapentin, Carbamazepine, Pregaba• Local anesthetics

– Parenteral, oral, topical• Topical capsaicin• Opioids for selected patients

Multidisciplinary Pain Clinic Personnel

• Physicians

– Neurosurgeon– Orthopedic surgeon– Anesthesiologist– Neurologist– Physiatrist– Internal medicine– Psychiatrist– Addictionologist

• Nurses• Psychologists

• Physical Therapist• Occupational Therapist• Vocational counselor• Social worker• Dietician• Recreational staff• Administrative support staff

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