Many times when there is a serious medical case, we see the doctors advising intravenous fluids to be given. Why? It’s a part of fluid therapy. The human body consists of around 55 to 60 % of water, a newborn baby has water content of around 95% whereas an obese person has water content of 40%. When water or fluid in your body decreases than the needed ratio, you start feeling lightheadedness, fatigue and weakness. Some times severe fluid loss can lead to convulsions or even coma. So as to boost up the level of fluids in our body, intravenous fluids are registered.
Intravenous fluids are balanced electrolyte solutions (salt) which are administered inside the venous circulation. Mostly these intravenous fluids are composed of infusion of crystalline substances like potassium chloride, sodium chloride or even glucose.
The most prominent intravenous fluids used in the clinical world are Crystalloids and Colloids. Crystalloids are the sterile water solutions constituting electrolytes so as to adjust the mineral content of plasma in humans. These crystalloid solutions are available in varied range of formulations and can be hypotonic, hypertonic as well as isotonic. The most prominent example of crystalloids type of intravenous fluid is 0.9% normal saline. This was created to accommodate the electrolyte and also the mineral concentration inside the human plasma. LR is another alternative to normal saline which is very close to the human plasma in electrolyte concentration and also constitutes a little measure of lactate. Colloids are based on crystalloid solutions and hence are composed of both electrolytes as well as water. But along with these two components colloids also contain a colloidal substance that cannot spread freely in the presence of semipermeable membrane. The most common example of this type of intravenous fluid is human serum albumin that carries a molecular weight of 69000 d and is considered as the biggest substance in human blood in context with the colloid osmotic pressure. Albumin too comes in different formulations like isotonic formulation (5%) and hyperoncotic formulation (25%). Hetastarches another colloid formulation is composed of 10% of pentastarch and 6% hetastarch.
When the colloid solutions are administered they improve or maintain the osmotic pressure in the patients whereas when the crystalloid solutions are administered the osmotic pressure is slightly decreased due to hemodilution. Another major difference from a non-clinical perspective is that crystalloid intravenous fluids are comparatively cheaper than the colloid intravenous fluids. This is one reason why crystalloid intravenous fluids are more used as it lessens the pharmacy expenditure. Also many hospitals and doctors are unaware of the edge colloid intravenous fluids have over crystalloid fluids.
All normal medicines carry some amount of side effects and risk. Similarly intravenous fluids too carry some amount of risk and it is presumed by the doctors while choosing the type of fluid. According to the SAFE study conducted by Australia and New Zealand Intensive Care Society's Clinical Trials Group (ANZICS-CTG) some specific analysis came to light. Patients traumatically injured and in requirement of fluid resuscitation died if they were given colloid intravenous fluids, especially in cases of traumatic brain injury. While in contrast, in case of administration of the same intravenous fluid to the sepsis patients, the death rate showed a noteworthy declining graph. So, its all depending upon the choice of intravenous fluid selected by the doctor. Also contamination of these fluids has taken more lives in recent times, especially in pregnant women.
Nowadays, though more attention is being given to fluid resuscitation and its consequences due to which this branch of science involving fluid administration is rapidly growing. So, as to alter the inflammatory responses of the intravenous fluids nowadays, the crystalloid intravenous solutions also include ethyl pyruvate. This also helps to improve survival in cases of sepsis and shock. Recently, scientists have discovered new biological influences of colloids such as the albumin has been found out to be an antioxidant improver in case of critically diseased patients. Also starch solutions have been found to influence microcirculation. The latest clinical researches have also revealed that use of specific colloidal intravenous fluid for administration can help in checking the inflammatory injury to lungs due to shock. Albumin, the most common colloid solution is also being used more popularly especially for improving conditions in spontaneous bacterial peritionitis, ascites as well as acute injury to lungs.