Introduction
The main concept of fluid therapy has been extended to include the four “D's, such as drug, dose, duration, and de-escalation. The drug is selected based on the different compounds, such as crystalloids versus colloids, synthetic versus blood-derived, balanced versus unbalanced, and intravenous versus oral. The concentrations of other metabolically active substances like lactate, acetate, malate, and others, as well as the osmolality, tonicity, pH, and electrolyte composition, are all equally significant factors. When determining the type and quantity of fluid for a given patient at a given time, clinical factors must be taken into account. Fluid administration is only indicated in the following four situations such as resuscitation, maintenance, replacement, and nutrition or a combination of these.
What Is the Importance of Duration in Fluid Therapy?
The longer the delay in fluid administration, greater the organ damage, ischemia-reperfusion injury, and subsequent microcirculatory hypoperfusion. Murphy and colleagues examined the effects of early adequate versus early conservative and late conservative versus late liberal fluid administration in sepsis patients and discovered that early adequate and late conservative fluid management resulted in the best prognosis. Data from various studies combined show that late conservative is possibly more crucial than early adequate fluid therapy.
How to Choose the Right Dose?
Choosing the right dose, as with other drugs, necessitates consideration of the pharmacokinetics and pharmacodynamics of intravenous fluids. Pharmacokinetics is the study of how the body reacts to a drug, resulting in a specific plasma and effect site concentration. The intravenous fluid shows pharmacokinetics that is affected by distribution volume, osmolality, toxicity, oncoticity, and kidney function. Finally, the half-life time is determined by the fluid type but also by the condition of the patient and the clinical context.
How Does the De-escalation of Fluids in Sepsis Patients Work?
Resuscitation can be withheld or withdrawn at the end of fluid therapy if there is no longer a need for it. Fluid therapy for antibiotics should be administered as soon as possible, and the volume should be tapered once the shock has subsided. However, several physicians initiate fluid resuscitation using certain triggers but are unaware of triggers to stop it, thereby increasing the risk of fluid overload. In spite of the lack of strong evidence, intravenous fluids are being administered for a shorter duration.
Fluid responsiveness denoted a condition in which a patient responds to the administration of fluids with a significant rise in stroke volume and cardiac output or their surrogates. It is generally accepted that a threshold of 15 percent is best used to define cardiac output because it shows the least significant change in measurements. Fluid responsiveness implies that the slope of the Frank-Starling relationship is steep. Studies have shown that fluid responsiveness in intensive care units occurs in only half of the patients receiving fluid challenges. The negative effects of fluids must also be considered in their pharmacodynamics.
Why Is Fluid Balance Important?
The total of all fluid intakes and outputs over a 24-hour period is known as the daily fluid balance, and the total of all daily fluid balances over an extended period of time is known as a cumulative fluid balance. Both resuscitation and maintenance fluids are included in intakes. In addition to insensible losses, which are challenging to quantity, outputs should ideally also include urine, ultrafiltration fluids, third space, or gastrointestinal losses. Only daily requirements should be met with maintenance fluids, and their prescription should take into account for these additional sources of fluid and electrolytes. Therefore, specific intravenous maintenance fluids should be stopped when a patient already receives their daily requirements for water, glucose, and electrolytes from another source (parenteral or enteral nutrition, medication solutions).
How Does De-escalation Is Achieved?
The de-escalation of fluids is achieved by
First Phase: Resuscitation
The patient will have the “ebb” phase of shock after the initial shock. It can be sepsis, burns, pancreatitis (inflammation of the pancreas), or trauma. Severe circulatory shock is a life-threatening phase, and it can occur in minutes and is characterized by significant vasodilation, resulting in low mean arterial pressure and microcirculatory impairment. It may be associated with either high or low cardiac output. In general, fluid resuscitation is administered within three to six hours after the onset of therapy in accordance with an early, adequate, and goal-directed fluid management plan.
Second Phase: Optimization
The second hit happens within hours and is related to ischemia and reperfusion. Fluid accumulation at this stage reflects the severity of the illness and could be considered a “biomarker” of organ failure. Fluid responsiveness indices are once again critical, as fluid administration should be stopped when these indices become negative. Second, consider the clinical context. Obviously, more fluid is required in peritonitis septic shock than in pneumonia septic shock.
Third Phase: Stabilization
With successful treatment, stabilization should occur shortly after the optimization phase. It differs from the previous two in that there is no shock or threat of shock. The emphasis is now on organ support, and this phase corresponds to the point at which a patient has reached a stable and steady state. Fluid therapy is no longer required for ongoing maintenance in the presence of normal fluid losses and replacement fluids if the patient is experiencing ongoing losses due to unresolved pathologic conditions. Because maintaining a positive daily fluid balance is highly linked to a higher mortality rate in septic patients.
Fourth Phase: Evacuation or De-Escalation
After the second hit, the patient may either recover further, entering the flow phase with the spontaneous evacuation of the excess fluids that have been administered previously or, as is the case in many critically ill patients, the patient remains in a “no-flow” state followed by a third hit, usually resulting from globally increased permeability syndrome with ongoing fluid accumulation due to capillary leak. In any case, the patient enters a phase of “de-resuscitation.” It specifically refers to late goal-directed fluid removal and late conservative fluid management. Late goal-directed fluid removal entails aggressive and active fluid removal using diuretics and renal replacement therapy with net ultrafiltration.
Late conservative fluid management refers to a moderate fluid management strategy used after the initial treatment to avoid or reverse fluid overload. Recent research has found that two consecutive days of negative fluid balance within the first week of an intensive care unit stay is a strong and independent predictor of survival.
Conclusion
Fluid administration during the early hemodynamic resuscitation of septic shock patients continues to be a significant therapeutic challenge. Evaluation of fluid status and recommendation of fluid administration or removal are two of the most frequently performed interventions in critically ill patients. De-resuscitation is not supposed to be performed too quickly, or too long, or in an aggressive manner. Concerning the type, amount, and timing of intravenous fluid administration, there are still a lot of unanswered questions.
