Last updated: April 13, 2023
The distribution of blood pressure and blood flow in the vascular system is governed by physical principles. The propagation of the pressure pulse in large arteries depends upon the elastic properties of the arteries. The knowledge of hemodynamics is very important for a thorough understanding of the functioning of the circulatory system. Hemodynamics refers to arterial pressure or cardiac output (i.e., the basic measure of cardiovascular function). It is the study that is concerned with the flows and distribution of pressures in circulatory systems1.
Hemodynamically unstable patients have abnormal or unstable blood pressure that results in improper circulation and organs of the body do not receive adequate blood flow. Hemodynamic instability is characterized by chest pain, confusion, hypotension (i.e., low blood pressure), abnormal heart rate, loss of consciousness, restlessness, shortness of breath, cold hands, arms, legs, or feet, etc2. In most prehospital care systems like ATLS (advanced trauma life support systems), high volume IV fluid therapy is accepted as a standard treatment for hemodynamic instability.
IV fluid resuscitation is a therapy used as a life-saving intervention for the treatment of patients following severe trauma, or a major surgery, and for the treatment of sepsis. Fluid resuscitation promptly restores, or maintains organ perfusion, expands blood volume, and can be a life-saving intervention for hemodynamically unstable patients3.
The use of resuscitation fluids is the most common intervention in medicine. However, there is always uncertainty about which fluid to use and how to administer it. IV fluid administration is just like any other pharmacological prescription. The main indications for intravenous fluid administration include:
The R.O.S.E (Resuscitation, Optimization, Stabilization, Evacuation) conceptual model briefs a dynamic approach to fluid therapy, maximizing benefits, and minimizing harm accurately. In particular categories of critical patients (i.e., with burns or trauma) fluid therapy should be applied even more carefully, considering the importance of their particular aims that are avoiding the consequence of fluid overload while maintaining peripheral oxygen delivery.
The duration of the IV fluid therapy is very crucial and the volume should be abated as soon as the shock is resolved. Starting triggers for fluid resuscitation are very obvious, however, clinicians are usually less aware of the stopping triggers. The ultimate step in fluid therapy is the withdrawal of the fluids when they are no longer needed. This reduces the risk of fluid overload and other deleterious effects4.
Fluid administration is one of the keystones for hemodynamic resuscitation of critically ill patients. However, the administration of too much fluid can result in harmful consequences on various organs, e.g., renal function wound healing, and worsening gas exchange. Hypertonic saline (HTS) should be considered for hemodynamically unstable patients. The addition of colloids should also be considered within prescribed limits for each solution in such patients5.
It is important to note that a particular patient will have a particular need and baseline fluid depending upon multiple factors including, comorbid disease, age, and current diagnosis. In addition to this, it is essential to consider the indices of fluid tolerance such as lung water, hemoglobin levels, CVP, and oxygenation. Fluid requirements vary throughout the course of illness. The fluids must be prescribed on the basis of individual patients. The prescription must be regularly tailored and reviewed according to the evolving changes in the clinical stage to avoid any dangerous situation.
The prescription of IV fluid therapy is considered one of the most common acts for hospitalized patients, however, many aspects of this practice are surprisingly complex. To avoid fluid-induced harm or related mishaps, it is recommended to carefully evaluate the chosen solution, make a phase-wise approach for its administration, and take the clinical course of the disease or surgical procedure into account. Fluids should be administered with immense care as is done in the case of other drugs, every possible effort should be made to avoid unnecessary administration of the fluid to the patient.
IV fluid resuscitation is considered as a life-saving intervention for hemodynamically unstable patients. The patients showing symptoms like chest pain, confused behavior, hypotension (i.e., low blood pressure), abnormal heart rate, loss of consciousness, restlessness, shortness of breath, etc., are considered as hemodynamically unstable and should be promptly treated with fluid therapy. In IV fluid therapy the point of prime importance is giving the right fluid in the right dose to the right patient at the right time. Any mistake can cause fluid-induced harm and even can be life-threatening.