Small Volume Fluid Challenge as a Predictor of Fluid Responsiveness in Patients With Circulatory Failure

Transthoracic Echocardiography Guided Small Volume Fluid Challenge as a Predictor of Fluid Responsiveness in Patients With Circulatory Failure: An Observational Study

Assessment of intravascular volume status is difficult in critically ill patients. Evidence suggests that only 50% of hemodynamically unstable patients respond to a fluid challenge. Moreover, if cardiopulmonary function cannot compensate for the increase in preload, fluid loading may compromise microvascular perfusion and oxygen delivery and cause or aggravate peripheral and pulmonary edema. Inappropriate fluid expansion can increase morbidity and mortality thus making it important to accurately assess fluid responsiveness in critically ill patients. The volume responsiveness can be defined as a 15% increase in stroke volume (SV) or cardiac output (CO) after a 500-ml infusion. This study tested whether echocardiographic parameters can predict fluid responsiveness in critically ill patients following a low volume 100-ml crystalloid solution infusion over 1 minute.

Fifty-four adult patients with circulatory failure were recruited for the study. As a routine work in adult critical care unit at Menoufia University hospital for patients with circulatory failure, a 100 ml bolus of normal saline solution was given to the patient over 1 minute through a central venous catheter or jugular cannula. For prediction of responders, echocardiographic parameters were recorded1 minute after bolus administration. The remaining 400 ml of normal saline solution was infused at a constant rate over 10 minutes, and echocardiographic parameters were recorded again. The mean echocardiographic measurements over three consecutive respiratory cycles were recorded along with heart rate HR, systolic, diastolic and mean arterial pressures, central venous pressure, and Temperature also mechanical ventilation parameter (tidal volume, respiratory rate and PEEP) for each patient. Patients with an increase in CO after a 100 ml or total 500-ml infusion over 10 minutes (ΔCO500) of 15% or more were classified as responders (Rs) and those without an increase in CO was classified as non-responders

Inclusion Criteria:

• Patients with acute circulatory failure
• Mechanically ventilated & sedated.(Tidal volume 6-8 ml/ kg, PEEP 5 mmHg, Richmond Agitation-Sedation Scale RASS (R) Score from zero to -3).
• Systemic inflammatory response syndrome
• Septic shock
• Controlled massive hemorrhage

Exclusion Criteria:

• Age of less than 18 years
• Cardiomyopathy
• Pulmonary edema
• Morbid obesity
• Pregnancy
• Increased intracranial tension
• Valvular heart disease
• Myocardial ischemia or infarction before the study