Fluid Optimization

Tailor Fluid Management with NICOM to Optimize Resuscitation 

Appropriate fluid administration plays a pivotal role in the management of patients who are experiencing significant hemodynamic challenges.

Suboptimal fluid resuscitation may lead to low perfusion state, while overly-aggressive fluid resuscitation can lead to volume overload and heart failure exacerbation^(1-2).

Hemodynamic Monitoring provides an insight into the patient’s cardiac status and organ perfusion. This insight enables a tailored approach to fluid management and drug titration which in turn implies providing better oxygen delivery to the tissues in patients who tolerate fluids, obviating excess fluids with edema and delayed extubation in those that don’t, and better usage of inotropes and drugs that improve tissue perfusion and oxygenation.

Given that cardiac output has traditionally required the use of invasive and costly pulmonary artery catheters whose benefit was sometimes outweighed by inherent risks, other proxies have been utilized. Central Venous Pressure (CVP) is the most widely used to serve as a rough guide to determine whether a patient requires fluids or conversely is well-hydrated or even congested. However, abundant literature has validated that CVP is unable to predict patient’s volume status and response to fluids and therefore should not be used to guide clinical decisions regarding fluid management ^(2-3). In addition, CVP is invasive, requiring insertion of a catheter into the patient’s large neck vein.

Patients who are particularly prone to complications arising from suboptimal fluid management and who benefit greatly from fluid optimization are:

• Peri-operative patients: Pre-op/intra-op/post-op and step-down, especially patients in high-risk due to underlying morbidity
• General and Surgical Intensive Care Unit: Sepsis, Shock, Transplant, Acute Renal Failure, Multi-Organ Failure
• Emergency Department: Sepsis, Shock, Trauma, Acute MI, Heart Failure, COPD

Passive leg raising (PLR) is a bedside maneuver that mobilizes the equivalent of approximately 250 ml of blood sequestered in the calf veins back to the heart. It is quick, safe and reversible. It provides information that very quickly helps to guide therapy.

A positive PLR test (increase of ≥10% in SVI or CI) implies that there is sufficient cardiac reserve to pump the increased preload forward; in other words, a positive test indicates that the patient is on the ascending limb of the Starling curve⁽²⁾ and hence fluid responsive. In cases where PLR is not possible, an alternative method to PLR is assessing change in Cardiac Index following the administration of 250ml fluid bolus. "Passive leg raising induced changes in cardiac output reliably predict fluid responsiveness”. Several studies validate the high sensitivity and specificity of NICOM based PLR. 

To view publications about Fluid Optimization click here

To understand the impact of PLR in hemodynamic monitoring it may be helpful to discuss specific clinical example

A 48 Year-old-female was admitted with Osteomyelitis and Cellulitis. Received Vancomycin and developed acute renal failure. Her urine output decreased, creatinine levels peaked at 7.4. Nephrology was consulted for dialysis.

A passive leg raising (PLR) challenge was performed, with a 34% increase in CI following leg raising which indicated that the patient was fluid responsive. IV fluids were given.

Following hydration the patient improved markedly and was later discharged with a creatinine level of 0.8, without any dialysis.

In this case by conducting a PLR while monitoring the patient with the NICOM the clinicians were able to choose the optimal management for the patient. Both in terms of clinical outcome as this patient might end up with permanent kidney damage necessitating lifelong dialysis or renal transplantation and in terms of cost.