To manifest enough energy for the body to perform tasks,
cells and tissues must burn food to create energy and alongside ends up
producing carbon dioxide as a waste product. During oxidative metabolism, there
is 20,000 mmol of CO2 produced per day so that’s why the lungs have
a huge responsibility to take care of that waste by expelling it from the
system. The concentration must be very low, in the lungs, so that CO2
can diffuse out from the blood and through the alveolar membrane. CO2
is then cleared from the body by exhaling through the mouth and nose.
Therefore, all the CO2 has now exited the body resulting in a high
concentration gradient between the blood in the capillaries surrounding the
alveoli’s located in the lungs. Oxygen concentration is much higher than the
carbon dioxide concentration in the lungs but in respiring cells, CO2
concentrations are always higher than oxygen and therefore a concentration
gradient is met. The frequency of expiration is dependent on the amount of CO2
produced in tissues and levels of CO2 are detected in the
chemoreceptors found in the medulla.
However, carbon dioxide serves more than to be just
waste; In the bloodstream, the concentration of CO2 plays a crucial
role in preserving a stable pH and helps the body figure out how often it is
needed to breathe. The lungs control the amount of CO2 that is in
our blood through the depth and rate of respiration; The body can combine
carbon dioxide with water to form bicarbonate (HCO3-).
This is an intermediate form of carbonic acid that has lost a proton (hydrogen
cation). If an individual such as an athlete was to breathe in and out at a
rapid rate from exercising or even hyperventilate, this would then result to
reduce the concentration of CO2 building up in the blood, hence
decreasing the concentration of bicarbonate. Consequently, there will be less
H+ ions in the bloodstream and pH will ascend and return to its normal state.
However, this is a short solution for how the body handles a decrease in pH.
There are other types of sources to elevate the
concentration of acid and this can be due to the pulmonary diseases, emphysema
and drugs like barbiturates (Bruno et al, 2012). These can decrease the lungs
capability to remove CO2 resulting in hypercapnia. Hypercapnia can
result in respiratory muscles to be weak and increase proinflammatory of
cytokines and apoptosis (Bruno et al, 2012).
If the pH levels were to drop down below 7.0, this would be respiratory
acidosis and can cause headaches, confusion and lack of concentration. If the
severity of the acidosis becomes much worse, then seizures may occur, and
patients could even fall into a coma. To bring a solution, a patient would need
to restore ventilation (Nessar et al, 2016). On the other hand, there is
respiratory alkalosis when there is increased ventilation which causes more
excretion of carbon dioxide and decreased blood levels. Hyperventilation is the
most common form of acute respiratory alkalosis and this may often derive from
the patient having anxiety attacks.
There are multiple methods of testing for these disorders
and one of them is using an arterial blood gas. This can prove if levels of CO2
are low for being compensated or if there is a low concentration of HCO3-.
Furthermore, this would prove for metabolic acidosis and this method is also
very useful as it indicates all other disorders, but it does not help in
whether the problem was caused by the lung or heart. This test can be
inaccurate as the patient could have had a recent smoke or could have a fever
and this can produce different results and not give a clear understanding. This
examination is best paired with other examination techniques such as the urine
test. Therefore, creatinine, urea or plasma levels can be observed so that it
can be determined if there is an issue with the kidney. This is a great way of
testing as it is cheap and reliable and can be processed back to the doctor
within three days. Using the patient’s own pH levels would be a poor indicator
as it could be affected by mixed disorders or compensation. The best optimal
screening option would be to pair both anion gap and testing for bicarbonate
serum as this can rule out disorders and help clinicians in determining and
recognising what acid-base disorders are present (Narins et al, 1980)
There are more ways to better diagnose a patient by
obtaining their clinical history and examining their physical condition
(Williamson, 1995). But finding acid-base disorders are common in hospitalised
patients so understanding the physiology of the disorders will help aid the
clinician to evaluate and select the correct diagnosis test to identify all