Respiratory Emergencies.1
Medical Emergency I
Dr. Maha Al Sedik
2015
Objectives:
1- Physiology of respiration.
2- Respiratory cycle.
3- internal and external respiration.
4- Blood circulation.
5- Cellular respiration.
6- Hypoventilation.
7- Hyperventilation.
Physiology of respiration
Story of breathing:
 Breathing means inhalation (breathe in) and exhalation (breathe
out).
 Oxygen enter the alveoli and pass into the capillaries
(bloodstream) to be used by the body ( inspiration).
 Waste (carbon dioxide) produced by the body to exit the
capillaries into the alveoli ( expiration ).
 The body requires a certain amount of oxygen for all activities.
 As workload increases, oxygen demand and use increase.
 As a result, waste production increases.
Respiratory Cycle
Inspiration
(breathing in)
Expiration
(breathing
out)
Inspiration:
1. Diaphragm & intercostal (rib) muscles contract.
2. Diaphragm moves downward.
3. Ribs move upward & outward, expanding chest cavity size.
4. Larger chest size allows air to flow into lungs.
Expiration:
Passive process allowing muscles to relax
1. Diaphragm rises.
2. Ribs move downward & inward, decreasing chest cavity size.
3. Smaller chest size allows air to flow out of lungs.
Process of respiration:
I- External respiration
 Gas exchange between blood and air at alveoli
 O2 (oxygen) in air diffuses into blood
 CO2 (carbon dioxide) in blood diffuses into air
II - Internal respiration
 Gas exchange in capillaries between blood and tissue cells
 O2 in blood diffuses into tissues
 CO2 waste in tissues diffuses into blood
External respiration
Internal respiration
Important rules
Rules:
1- My right is the heart and lung left.
2- My left is the heart and lung right.
3- Artery carries the blood Away from heart.
4- Veins carries the blood to heart.
Sup. And inf.
Vena cava
Tissue
Pulmonary artery
Lung
Heart
Aorta
Pulmonary
veins
Right atrium : takes
blood from the body
through vena cava.
Gives blood to right
ventricle.
Left atrium : takes
blood
from
lung
through
pulmonary
veins.
Gives blood to left
ventricle
Right ventricle:
Takes blood from right
atrium .
Gives blood to lung
through
pulmonary
artery.
Left ventricle: takes
blood from left atrium .
Gives blood to body
through Aorta
START
 Pulmonary artery carries deoxygenated blood
 Pulmonary veins carries oxygenated blood
 Pulmonary artery arises from right ventricle
 Pulmonary veins end at left atrium
 98% of inspired oxygen attached to the hemoglobin in RBC.
 Exchange of oxygen and carbon dioxide.
alveoli
cells
Cellular Respiration:
 Oxygen (O2) is used by the cells
 O2 needed in conversion of glucose to cellular energy (ATP).
 Carbon dioxide (CO2) is produced as a waste product
 The body’s cells die if either the respiratory or cardiovascular
system fails.
Cellular respiration
Hypoventilation
Impaired ventilation is caused by a variety of factors.
Causes:
 Conditions that impair lung function
• Pneumonia
• Pulmonary edema
• Asthma
• COPD
 Conditions that impair mechanics of breathing
• High cervical fracture
• Flail chest: ( fracture in more than 1 rib in more than one
position).
• Obesity hypoventilation syndrome.
 Conditions that impair neuromuscular apparatus
• Head trauma
• Intracranial infections
• Brain tumors
• Serious spinal cord injury
The hypoventilation will lead to:
 Carbon dioxide accumulates in the blood when the lungs fail to
work properly.
 Combines with water to form bicarbonate ions and hydrogen
ions.
 Results in acidosis.
 It also leads to hypoxia.
Hypoxia : low oxygen to cells
Causes of hypoxia:
Hypoxic hypoxia: not enough oxygen.
Anemic hypoxia: not enough hemoglobin.
Stagnant hypoxia: not enough perfusion.
Cyanosis
Hyperventilation
 Occurs when people breathe in excess by increasing rate
and/or depth of respiration.
 Releases more carbon dioxide than normal.
 Results in alkalosis.
 Triggered
by
emotional
distress
or
panic:
hyperventilation or hyperventilation syndrome.
hysterical
When do you consider hyperventilation normal?
Hyperventilation in a patient with acidosis may be the
body’s attempt to raise the pH level.
Treatment of hyperventilation may include:
 Sedation
 Psychological support:
• Breathing with the patient
• Having the patient count to two between breaths.
• Distraction techniques.
• Having the patient sing a song.
Reference:
AAOS Emergency Care in the Streets 7th Edition, Caroline
Jones & Bartlett, 2012; ISBN 13: 978-1-469-0922-1
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