The Effect of Intraoperative Goal Directed Restricted Fluid Therapy on Extravascular Lung Water

The Effect of Intraoperative Goal Directed Restricted Fluid Therapy Guided by Stroke Volume Variation Versus Standard Fluid Therapy on Extravascular Lung Water in Major Abdominal Operations: a Randomized Controlled Study

The aim of this study is to compare the use of Goal Directed fluid therapy guided by Stroke volume variation plus a restricted fluid management approach to standard fluid management in patients undergoing major abdominal operations.

Perioperative fluid management has an important impact on patient outcome. Under-resuscitation leads to hypoperfusion and over-resuscitation leads to tissue oedema. Intraoperative goal directed fluid therapy (GDT) has been reported to improve patient outcome in high risk surgical patients. GDT aims to optimize oxygen delivery through various strategies. The main three GDT strategies are:

1. Stroke volume optimization with fluids
2. Stroke volume variation (SVV) and pulse pressure variation (PPV) optimization with fluids.
3. Oxygen delivery index with fluids and inotropes Although GDT was recommended by professional societies in Europe and United Kingdom, these recommendations were recently challenged in many randomized controlled trials and meta-analysis.The effect of GDT on intraoperative fluid requirements was previously reported, however; its effect on extravascular lung water is not well studied.

Electrical cardiometry is a recent non-invasive technology for cardiac output measurement. Electrical cardiometry drive CO measurement from thoracic electrical bioimpedance. Good correlation was reported between CO measurements derived from electrical cardiometry and continuous thermodilution monitoring system.

Although many protocols for GDT have been reported in major abdominal operations, till now there is no consensus about the optimum protocol nor the optimum goals to achieve during fluid management. Major abdominal operations are characterized by major fluid shifts. Moreover, patients undergoing these operations are prone to impaired organ functions due to tissue oedema. Traditional standard care in major abdominal operations usually includes 6 ml/Kg/h balanced crystalloids (to restore insensible losses and maintenance requirements) in addition to replacement of blood losses. We hypothesize that the use of a more restricted fluid approach (2ml/Kg/h) + GDT guided by cardiometry will improve fluid management and decrease extra-vascular lung water.

The aim of this study is to compare the use of Goal Directed fluid therapy guided by Stroke volume variation plus a restricted fluid management approach to standard fluid management in patients undergoing major abdominal operations.

Inclusion Criteria:

• Patients scheduled for major abdominal operations

Exclusion Criteria:

• Patients with arrhythmias, pulmonary hypertension or impaired cardiac contractility.
• Patients with impaired liver or kidney function.
• Patients with BMI above 40.