Dead Spaces in Your Body

Dead Space, Okay this is not a Video Game commercial. This is the real Dead Space in our body.Are you curious about this ?. I hope your answer is yes, because i want to share for you an amazing miracle in our body, Dead Space.

It sounds creepy, but the meaning of dead space in here is not creepy at all. Dead space means the volume of a breath that does not participate in gas exchange. It is ventilation without per fusion. The dead spaces is in our respiratory system. Take a look figure 1.

Figure 1.

As you can see, the dead space exist in your respiratory track. The total of dead space is 150 mL from total air in the lung. Maybe you curious why this dead space so important. Okay, we will discuss it.

I hope you know what is Snorkeling or scuba diving. Snorkeling is the practice of swimming on or through a body of water while equipped with a diving mask, a shaped tube called a snorkel and usually fins. Snorkeling is a popular recreational activity, particularly at tropical resort locations. The primary appeal is the opportunity to observe underwater life in a natural setting without the complicated equipment and training required for scuba diving. At the same time, scuba diving is a mode of underwater diving in which a diver uses a self-contained underwater breathing apparatus  (scuba) to breathe underwater. when you learn about that underwater sport, the basic thing in respiratory system (dead spaces) is a must to know.

as you know, breathing in underwater is a main point when you apply for the underwater sport. Than, The ultimate goal of breathing is to continually renew air in the gas exchange areas of our lungs – to get oxygen in and carbon dioxide out. This process lead you to tidal volume and dead space volume. The volume of dead space air in every one is a fixed amount and is increased during SCUBA diving with the addition of the regulator second stage. We can see (Figure 1) that the volume of our dead space air takes up a proportion of our tidal volume. Since the volume of dead space air is fixed, the proportion of dead space air increases if our tidal volume decreases (i.e. we take smaller breaths) and vice versa. The higher the proportion of dead space air, the less gas exchange occurs in our lungs. This lack of gas exchange causes a build up of carbon dioxide which stimulates our breathing rate. The scuba driver ultimately end up breathing at a higher rate and use more air. You can imagine when that happen, right?. That explanation explain us more that what we imagine. That’s also why the scuba driver will practice to optimize the lung function especially in tidal volume and maintain the total amount of dead space. Now, do you understand the simple purpose of dead space ?

There is other purposes of dead space. They are

  1. making a bicarbonate-buffered blood and interstitial possible, it is because Carbon dioxide is retained inside the lung.
  2. increasing the affinity of hemoglobin for oxygen and improving O2 and stabilize the body temperature.
  3. allowing mucosiliary transport, because Particulate matter (gas) is trapped on the mucus that lines the conducting airways.
  4. improving the quality of airway mucus and humidify it.

The total dead space (also known as physiological dead space) is the sum of the anatomical dead space plus the alveolar dead space. To make it clear, let’s take a look in the Figure 2. Anatomical dead space is that portion of the airways (such as the mouth and trachea to the bronchioles) which conducts gas to the alveolar. No gas exchange is possible in these spaces. Alveolar dead space is sum of the volumes of those alveolar which have little or no blood flowing through their adjacent pulmonary capillaries, i.e., alveolar that are ventilated but not perfused, and where, as a result, no gas exchange can occur. Alveolar dead space is negligible in healthy individuals, but can increase dramatically in some lung diseases due to ventilation-perfusion mismatch. The ratio of physiologic dead space to tidal volume is usually about 1/3.


There is a formula to count the dead space, but i am not going to discuss it in here. Maybe in other topics.

Sometimes, dead spaces will increase in number of volume. This situation cause by this following situation. They are:

  1. General anesthesia – multifactorial, including loss of skeletal muscle tone and bronchoconstrictor tone
  2. Anesthesia apparatus/circuit
  3. Artificial airway
  4. Neck extension and jaw protrusion (can increase it twofold)
  5. Positive pressure ventilation (i.e. increased airway pressure)
  6. Upright posture as opposed to supine (because of decreased perfusion to the uppermost alveolar)
  7. Pulmonary embolus, PA thrombosis, hemorrhage, hypotension, surgical manipulation of pulmonary artery tree – anything that decreases perfusion to well-ventilated alveolar
  8. Emphysema (blebs, loss of alveolar septa and vasculature)
  9. Age
  10. Anti-cholinergic drugs

From this short article,we can conclude that dead spaces are exist in the human respiratory system. It has functions to keep respiratory system works. Sometimes dead space can increase, depend on the situation or the case. The Nurse should aware about this condition and decide to make a good decision for the patient.

My resources for this article are come from:


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