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Disorders of Ventilation and Gas Exchange Hypoxemia Hypercapnia Pneumothorax ( spontaneous vs. traumatic - tension vs. open ) Extrinsic (Atopic) Asthma vs. Intrinsic (Nonatopic) Asthma Emphysema ( type A - pink puffer patient vs. type B - blue bloater patient) Cor pulmonale Cystic Fibrosis

Answer 1

1) Hypoxemia

Hypoxemia refers to the low level of oxygen in blood, and the more general term hypoxia is an abnormally low oxygen content in any tissue or organ, or the body as a whole.Hypoxemia can cause hypoxia (hypoxemic hypoxia), but hypoxia can also occur via other mechanisms, such as anemia.

Hypoxemia is usually defined in terms of reduced partial pressure of oxygen (mm Hg) in arterial blood, but also in terms of reduced content of oxygen (ml oxygen per dl blood) or percentage saturation of hemoglobin (the oxygen-binding protein within red blood cells) with oxygen, which is either found singly or in combination.

While there is general agreement that an arterial blood gas measurement which shows that the partial pressure of oxygen is lower than normal constitutes hypoxemia, there is less agreement concerning whether the oxygen content of blood is relevant in determining hypoxemia. This definition would include oxygen carried by hemoglobin. The oxygen content of blood is thus sometimes viewed as a measure of tissue delivery rather than hypoxemia.

Hypercapnia

Hypercapnia is when there is too much carbon dioxide (CO2) in the blood. This is normally caused by hypoventilation of the body which leads to CO2 retention. Hypercapnia is defined as PaCO2 greater than 4.2kPa on an arterial blood gas (ABG).Hypercapnia can eventually cause hypoxaemia due to reduced respiratory drive.However; hypercapnia can conversely be caused by long term hypoxaemia which causes the body to compensate leading to increased CO2 in the blood. This is known as type 2 respiratory failure.

2) Pneumothorax

Pneumothorax” is the medical term for a collapsed lung. Pneumothorax occurs when air enters the space around your lungs (the pleural space). Air can find its way into the pleural space when there’s an open injury in your chest wall or a tear or rupture in your lung tissue, disrupting the pressure that keeps your lungs inflated.

Causes of ruptured or injured chest or lung walls can include lung disease, injury from a sport or accident, assisted breathing with a ventilator, or even changes in air pressure that you experience when scuba diving or mountain climbing. Sometimes the cause of a pneumothorax is unknown.

The change in pressure caused by an opening in your chest or lung wall can cause the lung to collapse and put pressure on the heart.

The condition ranges in severity. If there’s only a small amount of air trapped in the pleural space, as can be the case in a spontaneous pneumothorax, it can often heal on its own if there have been no further complications.

Traumatic pneumothorax

Traumatic pneumothorax occurs after some type of trauma or injury has happened to the chest or lung wall. It can be a minor or significant injury. The trauma can damage chest structures and cause air to leak into the pleural space.

Examples of injuries that can cause a traumatic pneumothorax include:

• trauma to the chest from a motor vehicle accident
• broken ribs
• a hard hit to the chest from a contact sport, such as from a football tackle
• a stab wound or bullet wound to the chest
• medical procedures that can damage the lung, such as a central line placement, ventilator use, lung biopsies, or CPR

Changes in air pressure from scuba diving or mountain climbing can also cause a traumatic pneumothorax. The change in altitude can result in air blisters developing on your lungs and then rupturing, leading to the lung collapsing.

Quick treatment of a pneumothorax due to significant chest trauma is critical. The symptoms are often severe, and they could contribute to potentially fatal complications such as cardiac arrest, respiratory failure, shock, and death.

Spontaneous pneumothorax (Nontraumatic pneumothorax)

This type of pneumothorax doesn’t occur after injury. Instead, it happens spontaneously, which is why it’s also referred to as spontaneous pneumothorax.

There are two major types of spontaneous pneumothorax: primary and secondary. Primary spontaneous pneumothorax (PSP) occurs in people who have no known lung disease, often affecting young males who are tall and thin. Secondary spontaneous pneumothorax (SSP) tends to occur in older people with known lung problems.

Some conditions that increase your risk of SSP include:

• chronic obstructive pulmonary disease (COPD), such as emphysema or chronic bronchitis
• acute or chronic infection, such as tuberculosis or pneumonia
• lung cancer
• cystic fibrosis, a genetic lung disease that causes mucus to build up in the lungs
• asthma, a chronic obstructive airway disease that causes inflammation

Spontaneous hemopneumothorax (SHP) is a rare subtype of spontaneous pneumothorax. It occurs when both blood and air fill the pleural cavity without any recent trauma or history of lung disease.

Tension pneumothorax

It is a life-threatening condition that can occur with chest trauma when air is trapped in the pleural cavity leading to a cascading impact including a rapid deterioration of a patient's ability to maintain oxygenation.

Tension pneumothorax is more likely to occur with trauma involving an opening in the chest wall. Recognizing and treating it quickly is important. This is particularly true for combat and SWAT team medics who are working in tactical environments and may often encounter thoracic trauma.

The military has collected vast amounts of data regarding tension pneumothorax and subsequent treatment. In the combat setting, tension pneumothorax is the second leading cause of death, and often it is preventable.

With time, more and more information is becoming available that will likely improve survival for patients in the urban prehospital setting. This article discusses the injury process that often leads to a tension pneumothorax as well as prehospital treatment.

Any open chest wound has a high probability of developing a tension pneumothorax. The medical provider needs to be keenly aware of the signs, symptoms and treatment of a tension pneumothorax.

TENSION PNEUMOTHORAX: INJURY OVERVIEW

A pneumothorax means air in the chest cavity. This occurs when air, either from the lungs or outside the body, enters the pleural space that is normally occupied by the lung. It is called a closed pneumothorax when the chest wall is intact. With an intact chest wall, a pneumothorax can be caused by several things, but the most frequently encountered cause is from trauma resulting in a rib fracture that punctures a lung, releasing air into the pleural space. The signs and symptoms for a closed pneumothorax are:

• Chest pain
• Tachypnea
• Dyspnea

Open pneumothorax

An open pneumothorax occurs when there is an opening in the chest wall, which can be the result of penetrating trauma such as a gunshot wound or stabbing. This opening allows air to move from the outside of the body, through the opening in the chest wall, and directly into the pleural space. The larger the hole, or holes, in the chest wall, the greater the amount of air that can enter the pleural space.

Remember, the opening can also be on the patient's back in the case of an entry or exit wound. The provider needs to check both the front, back, and sides of the patient for penetrating trauma. Additionally, if the patient is wearing body armor, it is important to check for atypical entry and exit sites that may occur from deflections due to the armor. The signs and symptoms are similar to a closed pneumothorax with the addition of sucking or gurgling sounds that may occur over the opening.

3) Asthma

Asthma is a chronic lung condition in which the airways narrow and become inflamed, which leads to wheezing, coughing, and chest tightness. Extrinsic asthma and intrinsic asthma are subtypes of asthma.

Intrinsic vs. extrinsic asthma

Intrinsic and extrinsic asthma are two subtypes of asthma, which people more commonly refer to as allergic and nonallergic asthma.

Both types cause the same symptoms. The difference between the two subtypes is what causes and triggers asthma symptoms. The treatments are similar for each type, although the prevention strategies differ

In people with extrinsic asthma, allergens trigger the respiratory symptoms. Common triggers for extrinsic asthma include:

• pollen
• mold
• dust mites
• pet dander
• cockroaches
• rodents

In some cases, a person is allergic to more than one substance, and several allergens trigger asthma symptoms.

In people with intrinsic asthma, allergies are not responsible for the symptoms. Instead, the following triggers cause symptoms:

• cold
• humidity
• stress
• exercise
• pollution
• irritants in the air, such as smoke
• respiratory infections, such as colds, the flu, and sinus infections

In some cases, intrinsic asthma can occur with no known cause.

• Extrinsic asthma occurs when the immune system overreacts to a harmless substance, such as pollen or dust. The body releases an antibody called immunoglobin E (IgE). The release of this antibody leads to inflammation and asthma symptoms.
• Intrinsic asthma occurs when something other than allergens triggers an immune system response. People are not always able to identify the trigger.

4) Emphysema

Emphysema is a lung condition that causes shortness of breath. In people with emphysema, the air sacs in the lungs (alveoli) are damaged. Over time, the inner walls of the air sacs weaken and rupture — creating larger air spaces instead of many small ones. This reduces the surface area of the lungs and, in turn, the amount of oxygen that reaches your bloodstream.

When exhale, the damaged alveoli don't work properly and old air becomes trapped, leaving no room for fresh, oxygen-rich air to enter.

Most people with emphysema also have chronic bronchitis. Chronic bronchitis is inflammation of the tubes that carry air to your lungs (bronchial tubes), which leads to a persistent cough.

Emphysema and chronic bronchitis are two conditions that make up chronic obstructive pulmonary disease (COPD). Smoking is the leading cause of COPD. Treatment may slow the progression of COPD, but it can't reverse the damage

Chronic bronchitis (blue bloaters)

• Patients may be obese.
• Frequent cough and expectoration are typical
• Use of accessory muscles of respiration is common
• Coarse rhonchi and wheezing may be heard on auscultation
• Patients may have signs of right heart failure (cor pulmonale), such as edema and cyanosis.

Emphysema (pink puffers)

• Patients may be very thin with a barrel chest
• They typically have little or no cough or expectoration
• Breathing may be assisted by pursed lips and use of accessory respiratory muscles; they may adopt the tripod sitting position
• The chest may be hyper resonant, and wheezing may be heard; heart sounds are very distant.

Emphysema (Pink Puffers)

Thin Appearance

Increased CO2 retention

Minimal Cyanosis

Purse Lip Breathing

Dyspnea

Hyper-resonance on Chest Percussion

Orthopneic

Barrel Chest

Exertional Dyspnea

Prolonged Expiratory Time

Speaks in short jerky sentences

Anxious

Use of accessory Muscles to Breath

Chronic bronchitis (blue bloaters)

Airway flow problem

Color is dusky to cyanotic

Recurrent productive cough

Hypoxia

Hypercapnia

Respiratory acidosis

High hemoglobin

Increased respiratory rate

Dyspnea on exertion

Digital clubbing

Cardiac enlargement

Bilateral lower extremity edema

5) Cor pulmonale

It is defined as an alteration in the structure and function of the right ventricle (RV) of the heart caused by a primary disorder of the respiratory system. Pulmonary hypertension is often the common link between lung dysfunction and the heart in cor pulmonale. Right-sided ventricular disease caused by a primary abnormality of the left side of the heart or congenital heart disease is not considered cor pulmonale, but cor pulmonale can develop secondary to a wide variety of cardiopulmonary disease processes. Although cor pulmonale commonly has a chronic and slowly progressive course, acute onset or worsening cor pulmonale with life-threatening complications can occur.

6) Cystic fibrosis

It is an inherited disorder that causes severe damage to the lungs, digestive system and other organs in the body.

Cystic fibrosis affects the cells that produce mucus, sweat and digestive juices. These secreted fluids are normally thin and slippery. But in people with CF, a defective gene causes the secretions to become sticky and thick. Instead of acting as lubricants, the secretions plug up tubes, ducts and passageways, especially in the lungs and pancreas.

Although cystic fibrosis is progressive and requires daily care, people with CF are usually able to attend school and work. They often have a better quality of life than people with CF had in previous decades. Improvements in screening and treatments mean that people with CF now may live into their mid- to late 30s or 40s, and some are living into their 50s.