Analgesics for Field and EAnalgesics for Field and

Report
Dr. Ghiamat MD Anesthesiologist
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The standard pre-hospital and immediate medical
treatment is focused on basic life support:
A – Airway
B – Breathing
C – Circulation
• One further element of patient care must be
addressed:
Pain management
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“Brutane”, until recently, was the analgesic
and sedative most often used:
◦ total immobilization by several adults and a
papoose via brute strength.
Paris PM. Amer J Emerg Med 1989
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No ideal sedative.
Fear of side effects.
Fear of addiction.
Inadequate training
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Patient experiences relief from pain without
sedation.
The Spectrum of Sedation
Patients may travel quickly in either direction along this spectrum!
Level of
Consciousness
Awake
Analgesia
Anxiolysis
Hypnosis
Protective
Reflexes
Present
Present
“Conscious
Deep
Sedation”
Sedation
Potential
Potential
Loss
Loss
ED/Transport Mgmt
General
Anesthesia
Total Loss
Sedation Protocol
Before
Procedure
Vital Signs
Baseline
Personnel #1
*Consent
(Performs Procedure)
*H & P
Personnel #2
(Monitors Patient)
*
During
After
Procedure
Procedure
Q 5 min.
Q 15 min.
*
*Records meds.
*Discharge
& Dosages
Instructions
Continuous Pulse Oximetry
*
*
Emergency meds, O2
*
*
suction and airway
equipment available
* = Present
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There must be a documented evaluation of
the patient’s anesthetic risk prior to
administration of conscious sedation using
the ASA rating.
ASA Classification Physical status classification of the American Society of Anesthesiologists
ASA CLASSIFICATION
MEDICAL DESCRIPTION OF PATIENT
COMMENTS
ASA I
No known systemic disease
May have consious sedation
without additional consultation.
ASA II
Mild systemic disease
May have conscious sedation
without additional consultation.
ASA III
Severe systemic disease(s)
Anesthesia consultation at
physicians's discretion
ASA IV
Severe systemic disease that is
a constant threat to life
Mandatory involvement of
Anesthesiology Department
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The early treatment of pain is important
Pain that is not relieved can have profound
effects on the patient
The effective management of pain helps to
promote:
• Feelings of well-being
• An environment where patients feel able to comply with
uncomfortable procedures
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Current analgesic alternatives may be less
than ideal due to:
Limited efficacy
Inconvenient administration – starve or
premed?
Length of onset or duration of action
Adverse reactions (e.g., respiratory
depression)
Narrow Therapeutic Window
Increasing tolerance requiring larger doses
(e.g. opioids)
•
Oral medications / sedatives –
•
Local anaesthetics - can produce
administration needs to be planned,
long onset, may be sedating.
very effective localised analgesia,
but long acting numbness follows:
– Topical creams
– Injections
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Inhaled analgesics:
– Nitrous Oxide – heavy equipment,
cleaning/sterilising, analgesia ceases on
cessation of inhaling the gas. Occupational
Health and Safety concerns for administrators in
closed environments?
– Methoxyflurane (trade name: Penthrox®) - vide
infra.
• IM
/ IV analgesia - usually
narcotics.
Unpredictable delayed onset of analgesia.
Side effects (nausea, vomiting, respiratory and
cardiovascular depression especially in the
shocked and/or injured). May require i/v access.
• IV
sedation – requires i/v access and
monitoring.
• General anaesthesia?
Used in Pre hospital, emergency and hospital
settings with a very rapid onset of action:
1. Inhaled Agents:
Nitrous Oxide & Oxygen
Penthrox (Inhaled methoxyflurane)
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2. Injected agents: Opioids (i.e. morphine)
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Nitrous oxide, commonly known as "laughing
gas",
Colorless, odorless gas.
Used 50/50 mixture with O2.
Safe and effective.
Wash-out with 100% O2 for 5 minutes.
Patient controlled titration. (Demand Valve)
Onset of action, 3 - 5 minutes.
Duration 3 - 5 minutes.
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Action
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Mild analgesia.
Sedation, amnesia.
Anxiolytic
Detached attitude towards pain.
Side Effects
◦ N. & V.
◦ Agitation
◦ Diffusional Hypoxia
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It diffuse into gas filled cavities ( e.g., the
intestines, thorax, middles ears) which
increases the volume and pressure in the
spaces.
Therefore, contraindicated in patients at risk
of pnumothrox, bowel obstruction, head
injury with impaired consciousness and
decompression sickness
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It causes the depression of myocardial
contractility and increase myocardial work
load.
It is associated with increase rate of mortality
with in patients with CAD.
Unintentional loss of consciousness.
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Low solubility in Blood and tissues and
rapidly eliminated from the body
Pollution exceeds recommended levels in
enclosed environment
In fact it has more than several hundred times
pollution effect than Methoxyflourane
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Impaired mental status.
Pregnancy
Pneumothorax
Bowel obstruction.
Children < 5 years.
Full stomach.
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Toxicity:
Blood disorders (megalobalstic Bone
marrow changes, agranulocytosis)
Interference with DNA
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Morphine , Pethidine & Fentanyl:
Powerful analgesia but addictive and subject
to abuse
It needs skilled supervision for administration
and needle stick injury
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Morphine , Pethidine & Fentanyl:
Powerful analgesia but addictive and subject
to abuse
It needs skilled supervision for administration
and needle stick injury
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Action
◦ Moderate to severe analgesia.
◦ Rapid onset of action
◦ Sedation, Euphoria,…
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Side Effects
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Nausea , Vomiting & Constipation
Tolerance and dependency
Respiratory Depression
Hypotension, tachycardia, palpitation,…
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Acute respiratory depression
Head Injury ( Increased Intracranial Pressure)
Phaechromocytoma ( risk of presser response
to histamine release)
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Difficulty of Intranasal administration:
Necessary to have titrated dose
Patient Positions (trauma patients…)
IV administration: satisfactory analgesia but
needs a 5- 10 minutes of each doses interval.
Continuous supervision is must
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Methoxy Flourane (MEOF) (Penthrox)
Only volatile anesthesia with significant analgesic
properties
Analgesia effect dose do not cause drowsiness or
unconsciousness.
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Onset of action after 6-8 breaths
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Inhaled Concentration is 0.1-0.4% (Low)
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Respiratory & Cardiovascular effect are
minimal
No need of closed supervision.
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Powerful, effective, simple, safe analgesia
No preliminary fasting or premedication
Rapid onset – analgesia begins in six breaths
1-1.5 minutes to establish
self administered intermittently
Stable cardio-respiratory systems
No vomiting, over-sedation
Simple equipment – easy to train and administer
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Almost all patients find Penthrox acceptable
Side effects rare and non-threatening
Occasionally drowsy if little stimulation – instantly
rousable
Very effective for children – they like its taste
Clinical observation only – no other monitoring
Quickly back to normal (driving/machinery not
recommended)
 Methoxyflurane has been clinically
demonstrated over many years to be a
simple, safe and effective agent for the relief
of pain and suffering.
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In Australia two million administration of
MEOF for the management of pre-hospital
pain relief in Ambulance Services in 30 years.
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Reduction or elimination of pain and
associated anxiety
Reduction of movement and reaction to
treatment
Improved health outcomes
WIN : WIN situation for both the patient and
clinician
“Few things a doctor does are more
important than relieving pain. Pain is soul
destroying…the quality of mercy is
essential to the practice of medicine; here
of all places it should not be strained.”
Angell M. Nejm, 1982

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