introduction to emergency medicine dr. tarek atia
TRANSCRIPT
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Introduction to
Emergency Medicine
Dr. Tarek Atia
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Book: The new manual of basic emergency
procedures; Firs aid and updated CPR
By: Professor Mohamed A. Seraj 2nd edition
A-2
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Subspecialty of Emergency Medicine
Pediatric Emergency Medicine
Toxicology
Sports Medicine
Undersea and Hyperbaric Medicine
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Challenges to Emergency Medicine
Interaction with difficult, intoxicated, or violent patients or
family members
Work in a “fishbowl” without 20/20 hindsight
Finding follow-up or care for uninsured
Limited resources
High stress
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Scope to emergency medicine
What make case emergency:
1. If acute
2. Life threatening
3. Chance of permanent morbidity.
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Asking question:
I) Multiple casualty
Within capability of the hospital.
Take patient with most serious situation.
II) Mass casualty
Beyond capability of the hospital.
Disaster
– Take patient with least serious case .i.e: the least intervention.
Clean the hospital.
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The golden hour:
Expression that time after the accident is of the
highest value.
Because there is high chance to reverse the situation.
THE EARLIER THE BETTER.
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II)Hospital care:
Behavior and treatment different between Emergency Room and word.
Because in ER there is no time (deal with the core of the problem).
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– Approach to ER pt:
History:– Allergy– Medication– Past illness/pregnancy. SMPLE Hx– Last meal.– Event/ environment.
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- Secondary survey: full history and exam and
investigation.
- Tertiary survey: must be seen by consultant next
morning.
- Re-evaluation.
– Definitive care: refer him to specialist.
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Don’t forget:
– Records.
– Consent for treatment.
– Forensic evidence. (Bullet, knife, clothes).
– Assume pt has cervical injury.
– Finally don’t be panic…
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ANATOMY AND PHYSIOLOGY
OF THE CARDIOVASCULAR
SYSTEM
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ANATOMY OF THE CARDIOVASCULAR SYSTEM:
- It is composed of: The Heart The blood vessels
Arteries Capillaries Veins
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THE HEART:
Fist-sized organ situated in the center of the chest,
between the sternum and the spine and above the
diaphragm.
It is surrounded by the lungs except in small area in front
of the heart known as the bare area and the area against
the spine.
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- It has a hollow tough muscular wall
surrounded by the pericardium.
- It is divided into right and left side and each side has 2
chambers, right atrium and ventricle and left atrium
and ventricle.
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THE VASCULAR SYSTEMIt comprises:
Ateries
Thick-walled, carrying blood from the heart under high
pressure.
Capillaries
Thin network of one cell layer.
Veins
Thin-walled vessels that carry blood under low pressure back
to the heart.
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Pulmonary Circulation
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Pulmonary Circulation
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Systemic Circulation
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Aorta and Major Arteries
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Arteries of the Head and Neck
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Arteries of the Brain
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PHYSIOLOGY OF THE HEART1- Heart pumps blood from the rt. ventricle into the pulmonary
artery to the lungs to purify the blood and from the left ventricle
into the aorta to distribute blood to the rest of the body.
2- Arteries carry blood away from the heart
3- veins carry blood back to the heart
4- Exchange of gases takes place in the capillary system throughout
the body.
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Functions
To purify the blood through the pulmonary capillary
system
To provide oxygenated blood to all tissues, through
the systemic capillary system.
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The heart beats 60-80 beats per minute during rest. The amount
of blood pumped by a single beat and known as the stroke
volume is ~70ml.
The heart pumps ~5 lit/min.Cardiac output is equal to stroke
volume multiplied by heart beats/min. That is to say
70x70=4900 (5 liters/min).
The heart can beat faster, up to 180-200 beats/min during
exercise, so it is capable of pumping up to 35 lit. per minute.
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Blood supply to the Myocardium:
Two coronary arteries, right and left, originate from the
first part of the aorta.
They are divided into several branches which encircles
the heart to supply the myocardium.
The coronary arteries are end arteries. There is no
venous coronary artery.
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Extrinsic Innervation of the Heart
The heart is stimulated by the
sympathetic cardioacceleratory
center
The heart is inhibited by the
parasympathetic
cardioinhibitory center
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Conduction system of the Heart
The contraction is known as systole and is followed by a
relaxation period known as diastole.
During systole the heart pump blood into the vascular
system, while during diastole the heart is relaxed and
receives venous return and recharges to prepare for the
next beat.
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Electrocardiography (ECG)
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Cardiac Cycle
Cardiac cycle refers to all events associated with blood flow
through the heart
– Systole – contraction of heart muscle
– Diastole – relaxation of heart muscle
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Phases of the Cardiac Cycle
Ventricular filling – mid-to-late diastole
– Heart blood pressure is low as blood enters atria and flows
into ventricles.
– AV valves are open, then atrial systole occurs.
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Phases of the Cardiac Cycle
Ventricular systole
– Atria relax
– Rising ventricular pressure results in closing of AV valves
– Isovolumetric contraction phase
– Ventricular ejection phase opens semilunar valves
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Phases of the Cardiac Cycle
Isovolumetric relaxation – early diastole
– Ventricles relax
– Back-flow of blood in aorta and pulmonary trunk closes
semilunar valves
Dicrotic notch – brief rise in aortic pressure caused by
backflow of blood rebounding off semilunar valves.
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Phases of the Cardiac Cycle
Figure 17.18a
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Phases of the Cardiac Cycle
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Heart Sounds
Heart sounds (lub-dup) are associated with closing of heart valves
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At RestHeart beat/minute = 70x1 = 70
Heart beat/hour = 70x60 = 4,200
Heart beat/day = 4200x24 = 100,800
Heart beat/year = 100,800x365 = 36,792,00
Volume pumped/min = 5lit
Volume pumped/hour = 5x60 = 300 lit
Volume pumped/day =300x24 = 7200 lit
Volume pumped/year = 7200x365 lit =2,628,000lit
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THE RESPIRATORY
SYSTEM
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The respiratory system has 4 components
– The Airway
– The neuromuscular system
– The Alveoli
– The vascular system, arteries, capillaries & veins
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1. THE AIRWAY Upper airway
-Nose and mouth
-Pharynx
-Larynx Lower airway
-Trachea
-Bronchi (right and left)
-Bronchioles
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2. NEUROMUSCULAR SYSTEMComprises of: Respiratory centre in the brain Nerves Muscles of respiration These are:
–Diaphragm
–Intercostal muscles
–Some muscles in the neck and shoulder girdle Chest cage: protects the lungs and the heart
–Spine at the back
–Sternum in front
–ribs around
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A- Respiratory centre in the brain &Nerves
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Muscles of respiration
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Chest cage
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Chest cage
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3. THE ALVEOLI
Minute air sacs, millions in number. They are made
of a very delicate thin membrane of one cell layer
forming a fine network. The capillaries are on the
outer side of the alveoli where exchange of gases
is carried out.
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4. PULMONARY VESSELS
Arteries carry dark blood with low oxygen levels from the
heart to the fine network of capillaries where O2 is picked-up
by the blood and CO2 is expelled in to the alveoli. The
oxygenated blood is the carried out to the left side of the
heart by the veins.
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PHYSIOLOGY OF RESPIRATION:The function of the respiratory system is to pick-up
oxygen from the air and expel carbon dioxide into the
air. Metabolism is a continuous process which needs
oxygen to function and as a result of this process,
carbon dioxide is produced. The Cardiovascular
system transports oxygen from the lungs to the cells
and transports carbon dioxide from the cells to the
lungs for elimination.
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The breathing mechanism is controlled and influenced
by the respiratory centre in the brain and primarily
the rate and depth of breathing is stimulated by
carbon dioxide in the arterial blood. As the level rises,
the respiratory centre sends a continuous parade of
signals via the nerves to respiratory muscles.
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This will result in an increasing rate and depth of breathing
until the level of carbon dioxide falls, then the breathing
rate and depth are returned to normal. This is known as
feedback mechanism between carbon dioxide level and
the rate and depth of breathing.
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Inspired Air Expired
O2 21% 16%
CO2 0.03% 4%
N2 79% 79%
Humidity Less More
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During respiration, 5% of oxygen passes from atmospheric air
into the blood through alveolar and capillary walls and 4% of
carbon dioxide is eliminated from the blood into the expired
air. Inspiration is an active process while expiration is a
passive process.