مشروع إعداد طبيب حكيم ناجح- المعهد العربي للتنمية المهنية المستدامة دورة الطوارئ و التخدير و الرعاية 8-4-2014

1. Acute Pain Management
Presented by
Dr. Hussein Sabri, FRCA, DA, DM
Professor Of Anesthesia & Intensive Care
Ain-Shams University – Cairo

2. Pain - definition
”an unpleasant sensory and emotional experience
with actual or potential tissue damage or described
in terms of such damage” (IASP, 1986)
“Pain is defined as an unpleasant sensation ,
which stimulates pain receptors e.g Bradykinin
,Histamine , Serotonin , K ions and prostaglandins”

3. Acute Pain Management
= Introduction
= Pathophysiology Of Pain
= Modalities in use
= Drugs in common use
= Epidural & intra-thecal techniques
= TENS
= Patient Controlled Analgesia
=Acute Pain management Service

4. Acute Pain Management
What do we mean by “ Acute Pain Management ” ?
Surgical as :
= Post Operative Pain
= Trauma
= Burns & Others . . . . . . . . . . . .
Medical as :
= Acute Myocardial Infarction
= Acute Pancreatitis
= Acute Herpes Zoster & Others . . . .

5. Acute Pain Management
Reasons often cited for poor analgesia
a = A belief that pain is not harmful to the patient/or that it
is a normal consequence of surgery & injury
b = Concerns that pain relief will obscure a surgical diagnosis
or mask the signs of surgical complications
c = A tendency to underestimate a patient’s pain and not
recognize the variability in patients’ perception of pain
d = Lack of frequent and regular assessment of pain and any
pain relieving measures
e = Fears that the patient will become addicted to Opioids

6. Acute Pain Management
Reasons often cited for poor analgesia – cont.
f = Concerns of a high risk of respiratory depression with
Opioids
g = Inadequate preoperative patient education regarding
postoperative analgesia
h = Patient reluctance to request analgesia
i = Lack of understanding of the enormous interpatient
variability in Opioids requirements
j = Lack of recognition that age is a better predictor of
Opioids requirement than weight in the adult patient

7. Acute Pain Management
Reasons often cited for poor analgesia – cont.
k = Prolonged dosing intervals and a belief that Opioids must
not be given often than every 4 hours
l = Insufficient flexibility in dosing schedules (dose /
intervals)
m = Lack of understanding of the need to titrate analgesics
to meet the needs of each patient
n = Lack of accountability for pain management and
considering the link ( . ) regional anesthesia & post op.
pain relief

8. Acute Pain Management
Why Should Acute Pain Management be improved ?
Possible harmful effects of under treated severe acute pain
Cardiovascular Tachycardia,hypertension, PVR,
myocardial.VO2, angina, DVT
Respiratory lung volumes, atelectasis
cough,Sp.ret, infection, O2
Gastrointestinal gastric & bowel motility
Genitourinary urinary retention
Neuro-endocrine Catabolic hormones
/metabolic Anabolic hormones
Musculo-skeletal m.spasm,immobility
Psychological Anxiety, fear, sleeplessness

9. Pathophysiological Aspects
Pain Mechanisms
Tissue damage caused by injury, disease or inflammation
releases endogenous chemicals, called algogenic, algesic or pain-
producing substances, into the extra cellular fluid that surround the
nociceptors.
These substances include H+, K+, serotonin, histamine,
prostaglandins, bradykinin, substance P (sP ), many others.
They play a causal role in pain associated with inflammation,
trauma, bone tumours, ischemia, and a variety of other
pathophysiologic conditions.

10. Pathophysiological Aspects – cont.
Pain Mechanisms – cont.
In addition to direct excitatory action on the membrane of
nociceptors, these agents may have an indirect excitatory action by
altering the local microcirculation.
The algesic substance can cause increased capillary
permeability and either vasoconstriction or vasodilatation.

11. Pathophysiological Aspects – cont.
Location Of Algesic Substances
Serotonin, histamine, K+, H+ prostaglandins and other members
of the arachidonic acid cascade are located in tissues; Kinins are in
plasma; and sP is in nerve terminals
Histamine is found in platelets, basophils, and the granules of
mast cells, Serotonin is present in mast cells and platelets.
Release of these amines may be induced by mechanical injury,
noxious heat, radiation, and certain by-products of tissue damage,
most notably neutrophil lysosomal materials, thrombin collagen, and
epinephrine.

12. Peripheral Nociceptor System
Somatic Structures: A. Skin
= Nociceptors : Distinct types, activated by tissue damage
= Free nerve endings : transmit transduced stimuli to the dorsal
horn of the Spinal cord or the Medulla
1- A- delta (high threshold mechanoceptors)
2- A-delta ( myelinated mechano-thermal nociceptors)
3- C- polymodal nociceptors
B. Muscles, Joints, Fasciae & other deep structures
by C- group IV-N. fibers & !! A-delta group III-N. fibers
Visceral Structures:
By C- and A-delta afferent fibers activated by disease,
inflammation, contraction, ischemia, rapid distention & others…

13. Peripheral Nociceptor System
Augmentation of nociceptors:
A. Sensitization: Repeated stimulation of most sensory organs
lead to fatigue ( less responsive )
*** But the Polymodal high threshold C-fibers show the
opposite response ----- prolonged , enhanced response
B. lowering of threshold: by pain producing substances
C. Segmental reflex responce
Inhibition of nociceptors: by counter irritation of the skin
e.g. Rubbing , Vibration , electrical stimulation or Acupuncture

14. Pathophysiological Aspects – cont.
Neurochemistry of endogenous opiate system
= Endorphins: 3 classes of Opioids:
1- Enkephalins
2- Dynorphins
3- β-endorphins
= Opiate Receptors: = ( mu ) – for morphine
= (Kappa)
= ( sigma )
= (epsilon )
= ( delta )

15. Pain is better managed with combination of
- Medications
- Educational programs
- Physical therapy
- Social interventions
- Psychological methods
- Complementary therapies
Pain can be treated

16. Acute Pain Management
Modalities in use
¤ Medications ( Opioids, NSAID, … ) given via :
= Oral = IM = IV = Rectal = TD = Transmucosal
= Intrathecal = Epidural = PCA / Accufusser
¤ Regional Analgesic techniques :
Epidural / Intrathecal / Nerve blocks / Intra-Articular
¤ Transcutaneous Electrical Nerve Stimulation ( TENS )
¤ Acupuncture ¤ Heat Application
¤ Cryoanalgesia ¤ Ultrasonic stim.

17. Pharmacological Aspects
Opioids & Non-steroidal Anti-inflammatory
Analgesics

18. Pharmacological Aspects
Opioids
# Morphine like substances
# Opium contains > 25 diff.alkaloids
# Opium contain 2 alkaloid types:
= Phenanthrene series ( morphine , codeine ) the only analgesic
= Benzylisoquinoline series ( as Papaverine … )
# Classification: a) Naturally occurring opium alkaloids as
Morphine , Codeine, Papaverine
b) Semi synthetic as Oxy & Hydromorphone,
& Heroin
c) Synthetic Opioids as Meperidine, Fentanyl,
Alfentanil, Sufentanil, Methadone, Naloxone,..

19. Pharmacological Aspects
Effects Of Opioids - cont
# ANALGESIA
= Possible side effects
# EFFECTS ON THE RESPIRATORY SYSTEM
= Respiratory depression
= Post-operative hypoxemia
# NAUISIA & VOMITING
= stimulation of the CTZ
# On CNS :
= Miosis, Sedation, Euphoria, Muscle rigidity
= Confusion

20. Pharmacological Aspects
Effects Of Opioids - cont
¤ = Antiemetics: Antidopaminergic ( Droperidol-Prochlorperazine-
Metoclopramide), Antiserotinergic ( Ondansetron ),
Anticholinergic,
Antihistamines
# EFFECTS ON THE CARDIOVASCULAR SYSTEM
Morphine vascular sympathetic tone ---- vasodilatation
# EFFECTS ON GIT & GUT : Altered smooth muscle activity
# PRURITUS – Histamine release / !! Centrally mediated
# ALLERGY

21. Pharmacological Aspects
Commonly used Opioid Agonists – cont
receptor agonists
¤ Morphine – new oral slow release formulation
¤ Papaveretum – a mixture of opium alkaloids
¤ Codeine – low affinity for Opioid receptors– good antitussive
¤ Diamorphine ( Heroin ) – no analgesic activity / is a prodrug
¤ Meperidine ( Pethidine ) – some atropine like actions
¤ Fentanyl & its analogues – Highly lipid soluble synthetic
¤ Tramadol – Centrally acting – ceiling dose 600 mg

22. Pharmacological Aspects – cont.
Nonsteroidal Antiinflamatory Drugs
= Often chemically unrelated
= Do not demonstrate tolerance
= All have analgesic properties
By inhibiting the formation of prostaglandins
= Cross the Blood Brain Barrier
= Salicylates : half life with ing dose
One week is needed to achieve steady state conc. When
the dose is 3 g / day

23. Pharmacological Aspects – cont.
Drug ( Generic ) Drug ( brand ) T ½ β (h)
Acetaminophen Novalgin 2.8
Aspirin(Salicylates) 0.25
Diclofenac Voltaren 1-2
Ibuprophen Brufen 2-2.5
Indomethacin Indocid 6
Ketoprophen 1.5
Ketorolac Ketolac 5.5
Piroxycam Feldene 48.5
** T ½ β (h): elimination half life
NSAID - Pharmacokinetics

24. Pharmacological Aspects – cont.
NSAID – Hazards & Toxicity
= Inter patient diff. in drug responsiveness
= The least toxic: coated, buffered aspirin, salicylate
= The most toxic is the taken in lowest doses
= GIT bleeding
= Renal toxicity
= Hematologic toxicity
= Hepatic toxicity

25. Pre-emptive Analgesia
Analgesics given to patients prior to the onset of pain
aiming to prevent changes in the spinal cord that
occur with repetitive painful stimuli from the site of
injury.
Benefits were shown only in animal studies but not in
clinical human studies – long term benefits may occur

26. Epidural & Intrathecal Analgesia
Epidural Analgesia
One of the most effective techniques available for the
management of acute pain
¤ Advantages :
¤ Safety Precautions ( When used on the ward )

27. Epidural & Intrathecal Analgesia
Drugs in common use
¤ Local Anesthetics:
= Xylocaine : 2 – 0.5 %
= Bupivacaine ( Marcaine) : 0.5, 0.25, 0.125, 0.1, 0.625 %
= Ropivacaine Hcl ( Naropin ) : 0.75 , 0.2 %
¤ Opiates:
= Morphine: 2-4 mg
= Fentanyl : 50 -200 m
¤ Others: As Clonidine, NSAID, Neostigmine, Ketamine, …

28. Epidural & Intrathecal Analgesia
Intrathecal Analgesia
¤ Local Anesthetics:
= Xylocaine : 2 %
= Bupivacaine ( Marcaine) : 0.5, 0.25, 0.125, 0.1, 0.625 %
¤ Opiates:
= Morphine: 2-4 mg
= Fentanyl : 50 -200 m
¤ Others: As Medazolame, Clonidine, NSAID, Neostigmine,
Ketamine, …

34. D
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35. Celiac Ganglion Block

36. Lumbar Sympathetic Block

37. Intercostal Nerve Block

38. Pain management in Trauma Patients
¤ Thoracic Injuries:
= Intercostal nerve blocks +/- parentral opiates
= Intra-pleural injection + catheter
= Thoracic epidural using local anesthetics ( Bupivacaine
0.25 % ) or narcotics ( morphine 2 mg or fentanyl 50 g )
¤ Pain management of intra abdominal injuries
= Aggressive pain management benefit upper abdominal &
high risk patients
= Low or mid thoracic epidural unless contra indicated

39. Pain management in Trauma Patients
¤ Pain management of extremity injuries [ Blunt / Penetrating ]
( Bony disruption, major somatic nerves, vascular injury, soft
tissue injury as in crush injuries )
= Sympathetic blocks : provide pain relieve & improve outcome
= Brachial plexus – Stellate ganglion – Lumbar sympathetic
= Catheter technique – use dilute solutions of LA
= narcotic addition is not indicated ( no opiate receptors )
= Tachyphylaxis to LA can occur - conc.
= Max. Bupivacaine dose = 0.4 mg /kg / hour
= In Reflex sympathetic dystrophy – after crush injuries –
sympathetic blockade remains the treatment of choice
= the same for Causalgia ( due partial somatic nerve injury )

40. Pain management in Trauma Patients
¤ Headinjured patients and pain management:
= In severe head injuries , pain management that interferes
with neurological monitoring should be avoided
= Neurological side effect with sedatives & Opioids !!!
¤ Pain management Paradigm for the trauma patient :
should be designed
¤ Contraindication to epidurals in trauma patients :
= Coagulation abnormalities / Sepsis / severe mental affection

41. Acute Pain Management Service “APMS”
* Started by Reddy in USA 1984
* Nurse based , Anesthesiologist supervised model
* Role :
- Education ( initial, update ) : to Anesthesiologists, Surgeons,
pharmacists, nurses, patients & families, medical & nursing
students, ………….
- Introduction of more advanced analgesic techniques as PCA
- Improving traditional analgesic treatment regimens
- Standardization of : Equipment, policies, medications
- 24 – hour availability
- Regular audit of activity and continuous quality improvement
- Clinical research.

42. ThankYou
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45. ThankYou
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