A Prospective Study Evaluating the Use of Intraoperative Stroke Volume Variation Via the FloTrac Device to Guide Fluid and Vasopressor Management in Head and Neck Free Flaps

Medical University of South Carolina (MUSC)

Status: Completed

Conditions: Head and Neck Cancer; Patients Requiring a Free Flap Surgery

Treatments: Device: FloTrac

Study type: Interventional

Funder types: Other

Identifiers

NCT02186938

ENT FloTrac

Details and patient eligibility

About

This study aims to investigate whether the intraoperative use of the FloTrac device to guide fluid and vasopressor management during head and neck free flap surgery improves postoperative outcome. Primary postoperative outcome is length of hospital stay. Secondary postoperative outcomes include days in ICU, days on ventilator, presence of postoperative pulmonary edema, need for postoperative vasopressors or transfusions, 30 day flap complication rate, inpatient postoperative cardiorespiratory complications/events, and overall 30 day flap failure rate.

Full description

Few animal models have shown that intravenous vasopressor administration (including use of pure alpha agonists such as phenylephrine) can decrease blood flow to free musculocutaneous flaps (1-3). This has led to a dogmatic belief that all vasopressors should be avoided intraoperatively during a microvascular free flap reconstruction regardless of patient hemodynamics, even though there is little published evidence that pressors negatively affect free flap outcome (4). As a result, these patients often receive generous amounts of fluids during their intraoperative course to combat periods of hypotension. However, patients receiving head and neck free tissue transfers tend to be older with serious comorbidities related to long term tobacco use such as significant cardiovascular and pulmonary disease. Thus, they often exhibit intraoperative hemodynamic lability with periods of hypotension that may not necessarily be related to hypovolemia. Consistently treating periods of hypotension with more intravenous fluids can lead to serious postoperative complications such as graft failure (4), pulmonary edema, and congestive heart failure. In fact, we have just completed a retrospective review of 248 patients over a 34 month period that received a head and neck free tissue transfer; we discovered that a 1ml/kg/hr increase in intraoperative fluid administration significantly increased 30 day flap complication rate while intraoperative administration of vasopressors did not affect 30 day flap complication or 30 day failure rate.

The FloTrac device is an approved and validated medical device that analyzes the arterial pressure waveform to calculate a stroke volume variation. This stroke volume variation can be used to better guide intraoperative patient therapy with regard to need for fluid vs. pressor management during periods of intraoperative hypotension (5). The use of the FloTrac device for goal directed therapy has been investigated in major abdominal surgery and found to decrease length of hospital stay and complication rate in this surgical population (5-6). Thus, it is possible that the intraoperative use of the FloTrac device can better guide anesthesia providers to provide the necessary therapy for intraoperative hypotension in patients undergoing head and neck freet tissue transfer, thus improving postoperative outcome.

Enrollment: 94 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• adults requiring "free flap" tissue reassignment surgery for head and neck cancer at either MUSC or Vanderbilt Medical Center

Exclusion criteria

• Patients < 55kg or > 140 kg based on literature regarding accuracy of flotrac.
• Patients with sustained intraoperative dysrrhythmias based on literature regarding accuracy of flotrac (ie, atrial flutter, atrial fibrillation).
• Patients with diagnosed NYHA class III-IV failure or documented EF < 30%
• Patients with pulmonary disease preventing administration of goal tidal volumes without excessive inspiratory pressures.

Trial design

Primary purpose: Supportive Care

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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94 participants in 2 patient groups

Usual Care

No Intervention group

Description:

Arterial line (radial, femoral, dorsalis pedis, or brachial), central line for access when needed, intubation vs tracheostomy, general anesthesia. We currently use stroke-volume variability monitoring (FloTrac) in all patients using the arterial line placed for blood pressure monitoring.

Treatment

Experimental group

Description:

The study will use a treatment algorithm for patients in the treatment group. This algorithm will aim to maintain a near-normal blood pressure and use goal directed therapy to achieve this. Currently the standard of care is to use IV fluid exclusively in these patients and anesthesia providers everywhere have been challenging that treatment plan. Our algorithm has an iterative approach assessing volume status, cardiac output and vascular tone in order, with interventions specified for each. Individual treatments have been proven safe and effective in this population, we believe this sequence may be the best current management system. By avoiding excessive fluid administration we expect to decrease ICU length of stay due to the comorbidities caused (pulmonary edema, bowl edema, glycocalyx damage).

Treatment:

Device: FloTrac