What is the recommended approach for a fluid response test in a clinical setting?

From the Guidelines

The recommended approach for a fluid response test in a clinical setting is to administer an initial fluid resuscitation of 30 mL/kg of crystalloid within the first 3 hours, with further fluid administration guided by frequent reassessment of hemodynamic status. This approach is based on the most recent guidelines for the management of sepsis and septic shock, which emphasize the importance of early and effective fluid resuscitation in stabilizing sepsis-induced tissue hypoperfusion or septic shock 1.

Key Considerations

• The use of dynamic over static variables is suggested to predict fluid responsiveness, where available 1.
• Initial fluid resuscitation should be titrated to the clinical response, and not solely guided by a predetermined protocol 1.
• The goal of fluid resuscitation is to improve tissue perfusion, and clinical endpoints such as mean arterial pressure, skin color and capillary refill, mental status, or urinary output should be used to guide fluid administration 1.

Hemodynamic Assessment

• A thorough clinical examination and evaluation of available physiologic variables, including heart rate, blood pressure, arterial oxygen saturation, respiratory rate, temperature, urine output, and others, should be performed to assess the patient's response to fluid resuscitation 1.
• Echocardiography may be useful in assessing the causes of hemodynamic issues, but its availability and applicability may influence its routine use 1.

Limitations of Static Measurements

• The use of central venous pressure (CVP) alone to guide fluid resuscitation can no longer be justified, as it has limited ability to predict a response to a fluid challenge when the CVP is within a relatively normal range 1.
• Other static measurements of right or left heart pressures or volumes also have limited utility in predicting fluid responsiveness 1.

From the FDA Drug Label

Emergency Treatment of Hypovolemic Shock Plasbumin-25 is hyperoncotic and on intravenous infusion will expand the plasma volume by an additional amount, three to four times the volume actually administered, by withdrawing fluid from the interstitial spaces, provided the patient is normally hydrated interstitially or there is interstitial edema. The recommended approach for a fluid response test in a clinical setting is to monitor the patient's hemodynamic response and observe the usual precautions against circulatory overload. The patient should be normally hydrated interstitially or have interstitial edema for the fluid response test to be effective. Additionally, the total dose should not exceed the level of albumin found in the normal individual, i.e., about 2 g per kg body weight in the absence of active bleeding 2.

• Key considerations:
  • Monitor hemodynamic response
  • Observe precautions against circulatory overload
  • Ensure normal hydration or interstitial edema
  • Do not exceed recommended dose
• Main goal: Expand plasma volume and maintain plasma colloid osmotic pressure.

From the Research

Fluid Response Test Approach

The recommended approach for a fluid response test in a clinical setting involves assessing the patient's ability to increase their stroke volume in response to fluid administration.

• Dynamic methods, such as pulse pressure variation (PPV) and stroke volume variation (SVV), are commonly used to assess fluid responsiveness 3.
• Fluid challenge techniques, including passive leg raising, mini-fluid challenge, and 10-s fluid challenge, can also be used to overcome the limitations of dynamic methods 3.
• The choice of fluid for resuscitation depends on various factors, including the patient's condition, the type of shock, and the presence of comorbidities 4, 5, 6.

Factors Influencing Fluid Responsiveness

Several factors can influence fluid responsiveness, including:

• Heart failure 7
• Hypothermia 7
• Immunocompromise 7
• Hyperlactemia 7
• Coagulopathy 7
• Delayed initiation of fluid resuscitation 7

Fluid Choice

The choice of fluid for resuscitation is crucial, and different fluids have distinct advantages and disadvantages.

• Crystalloids, such as balanced fluids (e.g., Ringer's lactate), may be preferable to normal saline due to the reduced risk of hyperchloremic acidosis 5, 6.
• Colloids, such as albumin, may be effective but are often more expensive 5.
• Hydroxyethyl starch solutions have been associated with detrimental effects on renal function 5.