JMIR Publications

ABSTRACT

Background:

Breast reconstruction is an integral part of breast cancer care. There are two main types of breast reconstruction: alloplastic (using implants), and autologous (using patient’s own tissue). The latter creates a more natural breast mound and avoids long-term need for surgical revision – more often associated with implant-based surgery. The deep inferior epigastric perforator (DIEP) flap is considered the gold standard approach in autologous breast reconstruction. However, complications do occur with DIEP flap surgery and can stem from poor flap tissue perfusion/oxygenation. Hence, the development of strategies to enhance flap perfusion (e.g., goal-directed perioperative fluid therapy) is essential. Current perioperative fluid therapy is traditionally guided by subjective criteria which leads to wide variations in clinical practice.

Objective:

The main objective of this trial is to determine whether the use of minimally invasive cardiac output (CO) monitoring for guidance of intravenous fluid administration, combined with low-dose dobutamine infusion (via a treatment algorithm), will increase tissue oxygenation in patients undergoing DIEP flap surgery.

Methods:

With appropriate institutional ethics board/Health Canada approvals and registration on Clinicaltrials.gov, DIEP flap surgical patients are randomly assigned to receive CO monitoring for guidance of intraoperative fluid therapy in addition to a low-dose dobutamine infusion (which potentially improves flap oxygenation) versus the current standard of care. The primary outcome is tissue oxygenation measured via near-infrared spectroscopy at the perfusion zone furthest from the perforator vessels 45 minutes after vascular re-anastomosis of the DIEP flap. Low-dose (2.5 g/kg/hr) dobutamine infusion continues for up to 4 hours postoperatively provided there are no associated complications (i.e., persistent tachycardia). Flap oxygenation, hemodynamic parameters, and any medication-associated side-effects/complications are monitored for up to 48 hours postoperatively. Complications, rehospitalizations, and patient satisfaction are also collected until 30 days postoperatively.

Results:

Funding and regulatory approvals were obtained in 2019 but recruitment interrupted by the COVID-19 pandemic. As of October 4th, 2023, 34 participants had been completed. Because of the significant delays with the pandemic, the expected completion date was extended.. We expect the study to be completed and ready for potential news release (as appropriate) and publication by July, 2024. No patients have suffered any adverse effects/complications with participation in this study and none have been lost to follow-up.

Conclusions:

CO-directed fluid therapy in combination with a low-dose dobutamine infusion via a treatment algorithm has the potential to improve DIEP flap tissue oxygenation and thereby, reduce complications following DIEP flap breast reconstruction surgery. However, given that investigators remain blinded to group randomization, no comment can be made regarding the efficacy of this intervention for improving tissue oxygenation at this time. Nevertheless, no patients have been withdrawn for safety concerns thus far, and compliance remains high. Clinical Trial: Clinicaltrials.gov (NCT04020172, July 15, 2019)