Use of a Mini-fluid Bolus to Identify Fluid Responsiveness

Adult patients whom the Consultant Intensivist decides should receive a fluid challenge as part of their standard care in order to improve haemodynamic parameters will be approached. Reasons for fluid administration include evidence of inadequate tissue perfusion such as raised blood lactate or poor urine output, hypotension or attempts to wean vasopressor dose.

Patients will be identified as suitable for inclusion by the Consultant Responsible for the Intensive Care Unit on each day. As fluid responsiveness is a transient phenomenon which disappears after significant fluid resuscitation it is proposed that patients will be immediately entered into the study so that the study contains a mix of fluid responsive and non-responsive patients in order to get the time critical data required which may be lost if there is a significant delay before study entry. Informed consent will be sought from the patient, or if they are incapacitated by critical illness, their relative will be approached for assent as soon as possible and within 48 hours of study enrollment. This is in line with recommendations for Research involving emergency treatment.

The LiDCOrapid machine will be connected in the same manner as the LiDCOplus machine, currently in use on ICU, in order to obtain the stroke volume measurement. A smartcard is inserted and the patient details entered. Monitoring will continue until fluids are clinically indicated. Patients will be given fluid boluses via either peripheral or central venous catheters.

The following data will be collected for each patient:

Age, Gender, Height, Weight, diagnosis requiring ICU admission, location of venous and arterial catheters, APACHE II scores, Cumulative fluid balance at time of bolus administration, Ventilation status (self-ventilating, non-invasive ventilation, invasive ventilation and mode if appropriate), tidal volume if measured, drugs being infused (sedatives, inotropes, vasoactive drugs, diuretics, muscle relaxants, etc), presence of renal replacement therapy.