Implementation of Fluid Strategies Using Real-time Bioelectrical Analyzer in Surgical Intensive Care Unit (SICU)

Implementation of Fluid Strategies Using Real-time Bioelectrical Analyzer of Postoperative Patients in Surgical Intensive Care Unit (SICU); a Novel Guidance to Set an Ideal Fluid Status of Patient in Acute Postoperative Phase

Precise assessment of postoperative volume status is important to administrate optimal fluid management. Bioelectrical impedance analysis (BIA) which measures the body composition using electric character. Extracellular water (ECW) ratio by BIA represented as the ratio of ECW to total body water (TBW) and is known to reflect the hydration status. Based on this, we aimed to determine whether aggressive fluid control using ECW ratio could improve clinical outcomes through a single blind, randomized controlled trial.

Critically ill patients admitted to an intensive care unit (ICU) after surgery have commonly experienced a large amount of wide organ injury and profuse bleeding resulting in vessel damage during surgery. Severe systemic inflammatory reactions and pathophysiological stress could consequently occur in these patients. For patients in an acute postoperative phase, it is important to maintain organ perfusion by correcting hemodynamic instability through fluid resuscitation.

Bioelectrical impedance analysis (BIA), a non-invasive method, is useful for quantitatively measuring body composition such as body fat and muscle mass. It is also useful for evaluating volume status based on resistance and reactance of cells known to have different electrical conductivity according to biological characteristics of body composition. In our previous study using BIA, the results showed that changes in ECW ratio after surgery were related to conventional parameters of overhydrated status such as daily fluid balance or capillary leak index (CLI). In addition, overhydration with value of ECW ratio above 0.390 on 3rd postoperative day appeared to be a risk factor for postoperative morbidity and mortality.

Herein, we aim to set the ECW ratio as a guideline for postoperative volume status and confirm a hypothesis that active intervention with fluid management to control the ECW ratio by BIA could lower clinical outcomes in patients with fluid imbalance through a prospective randomized controlled study.

Inclusion Criteria:

• Patients admitted to the surgical ICU after surgery under general anesthesia regardless of the type of surgery
• Patients who showed abnormal range of baseline ECW ratio by BIA (less than 0.390 or more than 0.405) that measured at the time of ICU admission

Exclusion Criteria:

• aged under 18 years
• underwent surgery under local or regional anesthesia
• pregnant
• had bone fixation or underwent limb amputation
• had any prosthetic medical devices such as pacemaker or metallic intravascular device
• stayed in ICU for less than 48 hours
• readmitted within 48 hours after ICU discharge
• diagnosed with renal failure and receiving renal replacement therapy
• underwent extracorporeal membrane oxygenation treatment before surgery
• agreed for do-not-resuscitate