This lesson will discuss two causes of respiratory failure, one of which occurs in adults and one of which occurs in infants.
You’ll also find out how too much alcohol can lead to one of these respiratory problems.
Struggling to Get Some Air
I think that we can begin this lesson by agreeing on something very understandable: difficulty breathing is no fun. It doesn’t matter whether it’s because you have asthma, you’re under water and can’t breathe, or some other reason; it’s always a very distressing time that can throw even the coolest cat into a big panic. But while you can use an asthma inhaler or get yourself out from under the water to finally get a good breath, the conditions we will be going over are, unfortunately, not so easily remedied and oftentimes have a very high fatality rate.
Acute Respiratory Distress Syndrome
One of these conditions is known as acute (adult) respiratory distress syndrome, or ARDS. This is a life-threatening condition that decreases the lungs’ ability to provide oxygen for the body as a result of damage to the alveoli and capillaries of the lungs. The alveoli are the air sacs of the lungs that inflate as you take a deep breath.
It is here that oxygen enters into the surrounding capillaries at the blood/air barrier and carbon dioxide leaves the body in order to be exhaled.When either the capillaries or the cells that make up the alveoli are damaged, the blood/air barrier of the lungs is compromised, and this leads to fluid leaking out of the body and into the alveoli, something we term ‘pulmonary edema.’ Since fluid in the alveoli causes impaired gas exchange by the lungs, the person’s blood becomes devoid of oxygen (termed ‘hypoxemia’), something that’s not conducive to life.Just think of the blood/air barrier as a very thin and fragile filter that separates a glass box filled with water (representative of your blood) on the left side and air on the right side. If anything damages this membrane from either the side where the air is or from the side where the water is, holes will develop in this membrane, and that will cause fluid to begin leaking into places where air used to be.You might be wondering what can lead to acute respiratory distress syndrome.
Well, the alveolar epithelium, made up of something called type I and type II alveolar cells, may be damaged as a result of something such as aspiration pneumonia. This is the inhalation of a foreign substance into the lungs. For instance, if gastric acid is inhaled into the lungs, then this can cause damage to the alveolar epithelium, leading to pulmonary edema and therefore acute respiratory distress syndrome.Hopefully, you’ve learned somewhere along the line that a drunk friend that passes out at a party should be put on their side instead of their back.
This is because if they vomit, the chances that they will inhale their vomit (and hence stomach acid) are much lower if they are lying on their side. The other side of the coin, or membrane, here, is a damaged endothelium. Damage to the capillary endothelium can result from something like sepsis, which refers to a serious condition that involves an infection causing massive inflammatory mediator release and subsequent damage throughout the entire body.
Infant Respiratory Distress Syndrome
What’s really terrible about respiratory distress syndrome is that it can also affect neonates, or newborns. The specific form of respiratory distress syndrome that affects neonates as a result of a lack of pulmonary surfactant is known as infant (neonatal) respiratory distress syndrome. Pulmonary surfactant is a lipoprotein formed by type II alveolar cells that reduces alveolar surface tension, keeps the alveoli from collapsing, and thereby makes it easier for the lungs to inflate during inhalation.
Infant respiratory distress syndrome is primarily seen in premature children born without enough surfactant. This leads to something known as a non-compliant lung. This term refers to the fact that the lungs are difficult to inflate as a result of this lack of pulmonary surfactant. This lack of surfactant in premature babies is the most common cause of respiratory failure in the days following birth. In order to help prevent the deadly consequences of this condition, synthetic surfactant can be placed inside of a baby’s lungs in order to help them breathe. In other cases, some parents have cows to thank for their children’s survival.
That’s right, pulmonary surfactant harvested from cows is used to save babies.
Acute Respiratory Failure
While you mull that over as you munch on that same cow during dinner, I think you can appreciate that both the adult and neonatal form of respiratory distress can lead to respiratory failure. Respiratory failure can cause hypoxemia (low blood oxygen), hypercapnia (high blood CO2), or both.
The causes of respiratory failure can be very sudden in onset, like aspiration pneumonia, or may occur over a long period of time due to something like chronic obstructive pulmonary disease.Diagnosis is made via arterial blood gases that measure the extent of the hypoxemia or hypercapnia, chest X-rays to help figure out the root cause of the problem, via pulmonary function tests, and an echocardiogram to look at the heart to make sure it’s not a contributory factor to the problems. Treatment always has to be specific to the underlying cause of respiratory failure.
Respiratory failure can occur as a result of acute (adult) respiratory distress syndrome, or ARDS. This is a life-threatening condition that decreases the lungs’ ability to provide oxygen for the body as a result of damage to the alveoli and capillaries of the lungs. ARDS can occur as a result of aspiration pneumonia, which refers to the inhalation of a foreign substance into the lungs, or sepsis, which refers to a serious condition that involves an infection causing massive inflammatory mediator release and subsequent damage throughout the entire body, to name just a couple of possibilities.Respiratory failure can also occur as a result of infant (neonatal) respiratory distress syndrome.
This is the specific form of respiratory distress syndrome that affects neonates as a result of a lack of pulmonary surfactant. Neonates are newborns, and pulmonary surfactant is a lipoprotein formed by type II alveolar cells that reduces alveolar surface tension, keeps the alveoli from collapsing, and thereby makes it easier for the lungs to inflate during inhalation.
Following this lesson, you should have the ability to:
- Define acute respiratory distress syndrome (ARDS), neonates and pulmonary surfactant
- Explain what causes ARDS
- Identify the causes of infant respiratory distress syndrome
- Describe the diagnosis and treatment of respiratory failure