Dr. Ghiamat MD Anesthesiologist

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

“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

No ideal sedative. Fear of side effects. Fear of addiction. Inadequate training

Patient experiences relief from pain without sedation.

Level of Consciousness Awake

AnalgesiaAnxiolysisHypnosis

“Conscious

Sedation”

Deep

Sedation

General Anesthesia

The Spectrum of Sedation

Patients may travel quickly in either direction along this spectrum!

Protective

ReflexesPotential

Loss

Potential

LossPresent Total LossPresent

ED/Transport Mgmt

Continuous Pulse Oximetry

Emergency meds, O2

suction and airway

equipment available

Personnel #2

(Monitors Patient)

Personnel #1

(Performs Procedure)

Vital Signs Baseline Q 5 min. Q 15 min.

*Consent

*H & P

*Records meds.

& Dosages

*Discharge

Instructions

Before Procedure

During

Procedure

After

Procedure

Sedation Protocol

* = Present

*

*

* *

* *

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 sedationwithout 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 Mandatory involvement of a constant threat to life Anesthesiology Department

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

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 – administration needs to be planned, long onset, may be sedating.

• Local anaesthetics - can producevery effective localised analgesia,but long acting numbness follows:– Topical creams– Injections

• 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)

2. Injected agents: Opioids (i.e. morphine)

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.

Action◦ Mild analgesia.◦ Sedation, amnesia.◦ Anxiolytic◦ Detached attitude towards pain.

Side Effects◦ N. & V.◦ Agitation◦ Diffusional Hypoxia

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

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.

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

◦ Impaired mental status.◦ Pregnancy◦ Pneumothorax◦ Bowel obstruction.◦ Children < 5 years.◦ Full stomach.

Toxicity: Blood disorders (megalobalstic Bone

marrow changes, agranulocytosis) Interference with DNA

Morphine , Pethidine & Fentanyl:

Powerful analgesia but addictive and subject to abuse

It needs skilled supervision for administration and needle stick injury

Morphine , Pethidine & Fentanyl:

Powerful analgesia but addictive and subject to abuse

It needs skilled supervision for administration and needle stick injury

Action

◦ Moderate to severe analgesia.◦ Rapid onset of action◦ Sedation, Euphoria,…

Side Effects◦ Nausea , Vomiting & Constipation◦ Tolerance and dependency◦ Respiratory Depression ◦ Hypotension, tachycardia, palpitation,…

Acute respiratory depression Head Injury ( Increased Intracranial

Pressure) Phaechromocytoma ( risk of presser

response to histamine release)

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

Methoxy Flourane (MEOF) (Penthrox)

Only volatile anesthesia with significant analgesic properties

Analgesia effect dose do not cause drowsiness or unconsciousness.

Onset of action after 6-8 breaths

Inhaled Concentration is 0.1-0.4% (Low)

Respiratory & Cardiovascular effect are minimal

No need of closed supervision.

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

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.

In Australia two million administration of MEOF for the management of pre-hospital pain relief in Ambulance Services in 30 years.

• 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