Transcript Introduction to Emergency Medicine - Home

Introduction to
Emergency Medicine
Dr. Tarek Atia

Book: The new manual of basic emergency
procedures; Firs aid and updated CPR

By: Professor Mohamed A. Seraj
 2nd edition
A-2
Subspecialty of Emergency Medicine

Pediatric Emergency Medicine

Toxicology

Sports Medicine

Undersea and Hyperbaric Medicine
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
Scope to emergency medicine

What make case emergency:
1.
If acute
2.
Life threatening
3.
Chance of permanent morbidity.

Asking question:
I) Multiple casualty
 Within
 Take
capability of the hospital.
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.
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.




So, there are two types of care:
I) Pre-hospital care:
• Consist of two types of supports:
1)Basic life support:
• Without intervention.
2)Advanced life support.
Like: intubations, Intra Venous line.
With intervention.
Very useful in cardiac patient.
Harmful in trauma patient. Because this take the golden hour
waiting for the ambulance.

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).

–
Approach to ER pt:
History:
– Allergy
– Medication
– Past
illness/pregnancy.
– Last meal.
– Event/ environment.
SMPLE Hx
Primary survey:
•
Airway
•
Breathing
•
Circulation
ABCDE STEP
BY STEP
•
Disability (CNS).
•
Exposure/ Environment: expose pt totally.
Then cover with the blanket.
Investigation:


ECG monitoring.
Urinary and gastric catheter: v-important. Good
urinary out put means proper fluid infusion.
–
Monitoring.
•
X-ray: vital x-ray only. (Pelvis, chest, cervical).
•
Diagnostic studies.
- 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.

Don’t forget:
–
Records.
–
Consent for treatment.
–
Forensic evidence. (Bullet, knife, clothes).
–
Assume pt has cervical injury.
–
Finally don’t be panic…
ANATOMY AND PHYSIOLOGY
OF THE CARDIOVASCULAR
SYSTEM
ANATOMY OF THE CARDIOVASCULAR
SYSTEM:
- It is composed of:
 The Heart
 The blood vessels
Arteries
Capillaries
Veins
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.
- 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.
THE
VASCULAR
SYSTEM
It 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
the heart.
pressure back to
Pulmonary Circulation
Pulmonary Circulation
Systemic Circulation
Aorta and Major Arteries
Arteries of the Head and Neck
Arteries of the Brain
PHYSIOLOGY OF THE HEART
1- 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.
Functions

To purify the blood through the pulmonary capillary
system

To provide oxygenated blood to all tissues, through
the systemic capillary system.

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.
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.
Extrinsic Innervation of the Heart
 The heart is stimulated by the
sympathetic cardioacceleratory
center
 The heart is inhibited by the
parasympathetic
cardioinhibitory center
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
Electrocardiography (ECG)
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
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.
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
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.
Phases of the Cardiac Cycle
Figure 17.18a
Phases of the Cardiac Cycle
Heart Sounds
 Heart sounds
(lub-dup) are associated
with closing of heart
valves
At Rest

Heart 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
THE
RESPIRATORY
SYSTEM
The respiratory system has 4 components
–
The Airway
–
The neuromuscular system
–
The Alveoli
–
The vascular system, arteries, capillaries & veins
1. THE AIRWAY
Upper airway
-Nose and mouth
-Pharynx
-Larynx
 Lower airway
-Trachea
-Bronchi (right and left)
-Bronchioles

2. NEUROMUSCULAR SYSTEM
Comprises 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
A- Respiratory centre in the brain &Nerves
Muscles of respiration
Chest cage
Chest cage
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.
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.
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.
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
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.
Inspired Air
Expired
O2
21%
16%
CO2
0.03%
4%
N2
79%
79%
Humidity
Less
More
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.