2. Objectives
• Be able to provide a definition for pain
• Have an understanding of pain assessment
and pain assessment tools
• Have a knowledge of analgesic drugs and
side effects of drugs
• Have an understanding of routes of drug
administration
4. “Pain is an unpleasant sensory and emotional
experience associated with actual or potential tissue
damage or described in terms of such damage.”
IASP (1979)
Definition of pain
• Implies emotional component.
• Pain can exist without tissue
damage.
5. PATHOPHYSIOLOGY OF PAIN
• Involves four physiological processes:
- Transduction
- Transmission
- Modulation
- Perception
6.
7.
8.
9. Pain Language
• Acute pain: lasts less than 6 months, subsides
once the healing process is accomplished.
• Chronic pain: involves complex processes and
pathology. Usually involves altered anatomy and
neural pathways. It is constant and prolonged,
lasting longer than 6 months, and sometimes, for
life.
10. Why Treat Pain?
• Basic human right!
• ↓ pain and suffering
• ↓ complications of unreleived pain
• ↓ chronic pain development
• ↑ patient satisfaction
• ↑ speed of recovery → ↓ length of stay → ↓
cost
• ↑ productivity and quality of life
11. Barriers to Effective Pain
Management
● Multidisciplinary factors
- lack of knowledge
- failure to recognize multi - faceted nature of pain
- poor interpretation of information
● Patient factors
- unwillingness to report pain
- non compliance with treatment
- lack of knowledge / information
13. Pain may be undertreated
Physicians may have concern that pain medications will:
- worsen hemodynamic instability
- produce harmful or long-lasting metabolites in the setting of
multiple organ dysfunction
- Impair the ability to examine a patient’s mental status.
However, these concerns must be balanced against harmful effects
of undertreatment of pain.
14. Adverse effects of unrelieved PainAdverse effects of unrelieved Pain
CardiovascularCardiovascular Heart Rate
Blood Pressure
Increased
myocardial o2
demand
Hypercoagulation
Unstable angina
Myocardial
infarction
DVT
PE
RespiratoryRespiratory Lung Volumes
Decreased cough
Retension of secretion
Atelectasis
Pneumonia
Hypoxemia
GIGI Gastric Emptying
Bowel Motility
Constipation
Anorexia
Ileus
National Pharmaceutical Council (2001). Macintyre & Schug (2007).Cohen et al (2004)
15. Adverse effects of unrelieved PainAdverse effects of unrelieved Pain
NeuroendocrineNeuroendocrine Altered release of
multiple
hormones
Hyperglycemia
Wt loss/ muscle
wasting
Impaired wound
healing
Impaired immune
function
MSKMSK Muscle spasm
Impaired muscle
mobility &
function
Immobility
Weakness
Fatigue
PsychologicalPsychological Anxiety
Fear
Sleep deprivation
Post traumatic stress
disorder
19. Pain Assessment
“One of the most important functions of the
nurse is to alleviate the suffering of people
who are experiencing pain”
Schofield P(1995)
20. Why we assess pain ?
• To establish degree and nature of pain
• To ensure patient comfort
• To evaluate effectiveness of analgesia
• To help alleviate anxiety
• To decide on type of analgesia
• To aid recovery and prevent complications
21. When should pain be measured
• Usually asked when pt. are resting .
• Better indicator is assessment of pain during
coughing , deep breathing or movement .
• Regular reassessment .
22. How to assess pain
• Communication with patient is essential
• Observe for changes in physiological signs
• Consider pain as 5th vital sign
• Use a pain scoring system
30. In patients who are unable to self-report and in
whom motor function is intact and behaviors are
observable.
The Behavioral Pain Scale (BPS) and the
Critical-Care Pain Observation Tool (CPOT)
are the most valid and reliable behavioral pain
scales for monitoring pain in
• Medical ICU
• Postoperative,
• Trauma (except for brain injury)
In patients who are unable to self-report and in
whom motor function is intact and behaviors are
observable.
The Behavioral Pain Scale (BPS) and the
Critical-Care Pain Observation Tool (CPOT)
are the most valid and reliable behavioral pain
scales for monitoring pain in
• Medical ICU
• Postoperative,
• Trauma (except for brain injury)
Identifying and Treating PainIdentifying and Treating Pain
Patients who can
self report
Numerical scale
Guideline do not suggest that vital signs be used alone for pain
assessment in adult ICU patients.
Guideline suggest that vital signs may be used as a cue to begin
further assessment of pain in these patients,
Assess pain ≥ 4 times per shift & as needed
31. Pain is a more terrible lord of
mankind than even death
37. What is the “Best Way” to manage
acute pain?
• FIRST , DO NO HARM
Therefore , the “best way” is a BALANCE
Patient
Safety
Effective
Analgesic
Modalities
38. How do we do it?
• Multimodal analgesia : Several analgesics with
different mechanisms of action , each working at
different sites in the nervous system
• Acetaminophen
• Non-steroidal anti-inflammatory drugs
(NSAIDs)
• Opioids
• NMDA Antagonists
• Local anaesthetics
• Non-pharmacologic methods
39. Methods of administration
• Epidural Analgesia
• Patient Controlled Analgesia [ intra - venous ]
• Intra Muscular Injection
• Sub Cutaneous
• Oral
• Rectal [ suppositories ]
• Transdermal
• Inhalation [ gas ]
• Regional Nerve Blocks e.g. Paravertebral, Brachial Plexus block.
• Wound Infiltration
40. Opioid
Opioid is a blanket term used for any drug
which binds to the opioid receptors in the
CNS.
43. PARACETAMOL
Mechanism of action: ? Selective inhibition of
prostaglandin synthesis in CNS
Analgesic and antipyretic
Oral , rectal and intravenous prep
Useful adjunct
44. NSAIDS
• Work at site of tissue injury to prevent the formation
of the nociceptive mediators Prostaglandins.
• Can decrease opioid use ~30% therefore decreasing
opioid-related side effects
• NSAIDs should be the first-line drug for treatment
of mild to moderate pain & should be used in
combination with opioids for more severe pain .
• Adv. : no sedation , resp. depression , N&V.
– Side effects : GI upset , gastric ulcers , decrease
renal medullary blood flow , reversible inhibition of
platelet function
45. NSAIDS
• Newer NSAIDS selectively (primarily) inhibit
cyclooxygenase-2 (COX-2) which is induced by
surgical trauma with minimal effect on COX-1
which is responsible for GI and platelet side effects
• Equivalent analgesic efficacy with non-selective
COX-inhibitors
• No effects on platelets!
• Much reduced incidence of upper GI S/E compared
to non-selective
• Duration of action about 24 hr.
46. NMDA Receptor Antagonists
• Ketamine :
- Ketamine 0.15 - 0.3 mg/kg IV with induction of
general anesthesia has pre-emptive analgesic effects
- less pain and less opioid use post-op
- Low dose (0.25-0.5 mg/kg) IV bolus followed by
infusion of 2-4 µg/kg/min , can provide significant
analgesia.
- Ketamine as co-analgesic , combined 1:1 with
morphine IV PCA . Better analgesia , less S/E
47. Dexmedetomidine :
- Highly selective- Highly selective αα22 agonist.agonist.
- Does not depress the respiratory drive.- Does not depress the respiratory drive.
- Causes- Analgesia dose-dependent , sedation- Causes- Analgesia dose-dependent , sedation
(“(“Cooperative sedationCooperative sedation”), anxiolysis.”), anxiolysis.
- Reduction in Sympathetic tone.- Reduction in Sympathetic tone.
- Useful adjunct to both opioid & non-opioidUseful adjunct to both opioid & non-opioid
analgesicanalgesic.
- Side effects : Bradycardia , Hypotension
- Dose : Loading dose – 1 µg/kg i.v. over 10 min ,
followed by infusion of 0.2-0.7 µg/kg/hr.
