Automated thermographic detection of blood vessels for DIEP flap reconstructive surgery.

PURPOSE: Inadequate perfusion is the most common cause of partial flap loss in tissue transfer for post-mastectomy breast reconstruction. The current state-of-the-art uses computed tomography angiography (CTA) to locate the best perforators. Unfortunately, these techniques are expensive and time-consuming and not performed during surgery. Dynamic infrared thermography (DIRT) can offer a solution for these disadvantages. METHODS: The research presented couples thermographic examination during DIEP flap breast reconstruction with automatic segmentation approach using a convolutional neural network. Traditional segmentation techniques and annotations by surgeons are used to create automatic labels for the training. RESULTS: The network used for image annotation is able to label in real-time on minimal hardware and the labels created can be used to locate and quantify perforator candidates for selection with a dice score accuracy of 0.8 after 2 min and 0.9 after 4 min. CONCLUSIONS: These results allow for a computational system that can be used in place during surgery to improve surgical success. The ability to track and measure perforators and their perfused area allows for less subjective results and helps the surgeon to select the most suitable perforator for DIEP flap breast reconstruction.

Tissue perfusion in DIEP flaps using Indocyanine Green Fluorescence Angiography, Hyperspectral imaging, and Thermal imaging.

Flap necrosis continues to occur in skin free flap autologous breast reconstruction. Therefore, we investigated the benefits of indocyanine green angiography (ICGA) using quantitative parameters for the objective, perioperative evaluation of flap perfusion. In addition, we investigated the feasibility of hyperspectral (HSI) and thermal imaging (TI) for postoperative flap monitoring. A single-center, prospective observational study was performed on 15 patients who underwent deep inferior epigastric perforator (DIEP) flap breast reconstruction (n=21). DIEP-flap perfusion was evaluated using ICGA, HSI, and TI using a standardized imaging protocol. The ICGA perfusion curves and derived parameters, HSI extracted oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) values, and flap temperatures from TI were analyzed and correlated to the clinical outcomes. Post-hoc quantitative analysis of intraoperatively collected data of ICGA application accurately distinguished between adequately and insufficiently perfused DIEP flaps. ICG perfusion curves identified the lack of arterial inflow (n=2) and occlusion of the venous outflow (n=1). In addition, a postoperatively detected partial flap epidermolysis could have been predicted based on intraoperative quantitative ICGA data. During postoperative monitoring, HSI was used to identify impaired perfusion areas within the DIEP flap based on deoxyHb levels. The results of this study showed a limited added value of TI. Quantitative, post-hoc analysis of ICGA data produced objective and reproducible parameters that enabled the intraoperative detection of arterial and venous congested DIEP flaps. HSI appeared to be a promising technique for postoperative flap perfusion assessment. A diagnostic accuracy study is needed to investigate ICGA and HSI parameters in real-time and demonstrate their clinical benefit.

Projected augmented reality in DIEP flap breast reconstruction: Projecting perforators on the skin using dynamic infrared thermography.

BACKGROUND: Dynamic infrared thermography (DIRT) is a quick and non-invasive technique for perforator mapping in free flaps that provides real-time information. After a cold challenge, areas best supplied with blood become visible hotspots on color-coded maps, indicating perforators. This study presents a proof of principle for a new and innovative feature of DIRT, where projected augmented reality is used to directly display thermal images on the patient's abdomen prior to the deep inferior epigastric artery perforator (DIEP) flap breast reconstruction. METHODS: A self-aligning projection device prototype (Anatomy Projector) equipped with an integrated thermal camera was used to obtain thermal information and project the color-coded map directly on the patient's abdomen before DIEP flap breast reconstruction. Projected DIRT hotspots were verified using a hand-held Doppler, and compared to the vascularity on computed tomography angiography (CTA), and intraoperative perforator measurements following a Cartesian grid. RESULTS: A total of 514 DIRT hotspots were projected in 50 patients, among them 97.3% could be verified using Doppler. The positive predictive value for CTA was 74.5%. Intraoperative measurements yielded 132 perforators in 71 flaps, among them 75 perforators (56.8%) correlated with projected DIRT hotspots, and half of them (54.7%) appeared within the first 5 emerging hotspots. CONCLUSION: This study showed that real-time display of thermal data in DIEP flap breast reconstruction is feasible via projected augmented reality. Projection facilitates convenient marking of hotspots, and a high resemblance to Doppler and CTA data was observed. Further research should assess the added value of projecting thermal images intraoperatively and in other fields of plastic surgery.

Simultaneous Co-surgeon Deep Inferior Epigastric Perforator (DIEP) Flap Breast Reconstructions: Feasibility and Clinical Outcomes.

BACKGROUND: A co-surgeon model is known to be favorable in microvascular breast reconstruction, but simultaneous co-surgeon deep inferior epigastric perforator (DIEP) flap cases have not been well-studied. The authors hypothesize that performing two simultaneous co-surgeon bilateral DIEP flap reconstructions results in non-inferior clinical outcomes and may improve patient access to care. METHODS: A single-institution, retrospective cohort study was performed utilizing record review to identify all cases of co-surgeon free-flap breast reconstructions over a 38-month period. Patients who underwent simultaneous bilateral DIEP flap breast reconstructions with the same two co-surgeons were identified. The control group consisted of subjects who underwent non-simultaneous reconstruction by the same co-surgeons within the same, preceding, or following month of those in the study group. Primary outcome variables were 90-day postoperative complications, while secondary outcomes were operating time, ischemia time, and length of stay. Descriptive statistics, univariate and multivariable regression analyses were performed. RESULTS: Overall, 137 subjects were identified and 64 met the inclusion criteria (n = 28 study, n = 36 control). There were no statistically significant differences between groups in body mass index, radiation, trainee experience, flap perforator number, immediate/delayed reconstruction, or length of stay. There were also no statistically significant differences in complications, including flap loss, anastomosis revision, take-back to the operating room, or re-admission. Operative time was longer in the simultaneous DIEP group (540.5 vs. 443.5 min, p < 0.01), but ischemia time was shorter in the simultaneous group (64.0 vs. 80.5 min, p < 0.01). CONCLUSIONS: A simultaneous co-surgeon approach to bilateral DIEP flap reconstruction may improve access to care and does not result in a higher complication rate compared with non-simultaneous bilateral DIEP flaps.

The influence of a previous implant-based breast reconstruction on postoperative sensation of the deep inferior epigastric artery perforator flap.

BACKGROUND: Implants and DIEP flaps have different outcomes regarding postoperative breast sensation. When compared to the preoperative healthy breast, implant-based breast reconstruction (IBBR) negatively influences postoperative breast sensation. However, it is currently unknown whether a prior IBBR also influences postoperative sensation of a replacing DIEP flap. The goal of this cohort study is to evaluate the influence of an IBBR on the postoperative sensation of a replacing DIEP flap. METHODS: Women were included if they received a DIEP flap reconstruction after mastectomy, with or without prior tissue expander (TE) and/or definitive breast implant. Sensation was measured at four intervals in 9 areas of the breast with Semmes-Weinstein monofilaments: T0 (preoperative, implant/no reconstruction), T1 (2-7 months postoperative, DIEP), T2 (± 12 months postoperative, DIEP), Tmax (maximum follow-up, DIEP). Linear mixed-effects models were used to investigate the relationship between an implant/TE prior to the DIEP flap and recovery of breast sensation. RESULTS: 142 women comprising 206 breasts were included. 48 (23.3%) breasts did, and 158 (76.7%) breasts did not have a TE/IBBR prior to their DIEP. No statistically significant or clinically relevant relationships were found between a prior implant/TE and recovery of DIEP flap breast sensation for the flap skin, native skin, or total breast skin at T1, T2, or Tmax. There were also no relationships found after adjustment for the confounders radiation therapy, BMI, diabetes, age, flap weight, follow-up, and nerve coaptation. CONCLUSIONS: An implant/TE prior to a DIEP flap does not influence the recovery of postoperative breast sensation of the DIEP flap.

Effect of corticosteroids on ischemia-reperfusion injury of deep inferior epigastric perforator flap after re-exploration for anastomosis thrombosis: A prospective randomized trial.

Patients undergoing breast reconstruction with the deep inferior epigastric perforator (DIEP) flap are at risk of arterial and venous thrombosis, necessitating flap salvage surgery. However, this carries the risk of ischemia-reperfusion injury (IRI) and potential significant partial or complete flap loss. The objective of this study was to evaluate the potential benefit of corticosteroids in reducing IRI related complications in DIEP flaps that are returned to the operation theater for attempted salvage after venous or arterial failure. A double-blinded prospective randomized study was conducted between January 2012 and January 2023 on patients scheduled for secondary unilateral breast reconstruction using the DIEP flap technique. Patients were included if they developed post-operative venous or arterial flap thrombosis and experienced DIEP flap IRI following operative take-back and anastomosis revision. The treatment group (TG) received a 5-day course of corticosteroids, while the control group (CG) did not receive any specific treatment. Forty-six patients were enrolled in the study. In the CG, two cases of total flap loss and eight cases of partial flap necrosis were observed, while the TG had only 1 case of partial flap necrosis (p < 0.05). The complete resolution of clinical signs of IRI occurred within 13 ± 2.1 days for the TG and 21 ± 3.5 days for the CG (p = 0.00001). The TG had a significantly shorter hospital stay (11.13 ± 0.38 days) compared with the CG (15.47 ± 1.27 days; p < 0.0001). Targeted corticosteroid therapy following a salvage procedure for vascular thrombosis in DIEP flaps has shown promise as an effective treatment for subsequent IRI. This approach may be considered as a viable option for managing IRI in free flaps. However, further studies involving a larger number of patients are required to substantiate our hypothesis.

Secondary solution for breast reconstruction following total DIEP flap loss: A single-center experience after 3270 DIEP flaps.

BACKGROUND: Total deep inferior epigastric perforator (DIEP) flap failure is a significant concern in autologous breast reconstruction. Literature on secondary reconstruction options following total flap failure is limited. This study outlines the outcomes of patients who underwent reconstruction post-DIEP flap failure at our institution. METHODS: We conducted a retrospective analysis of patients receiving autologous breast reconstruction between 2004 and 2021. We aimed to identify causes of total DIEP flap failure, outcomes of revision surgery, and outcomes of secondary breast reconstruction procedures. RESULTS: From 2004 to 2021, 3456 free flaps for breast reconstruction were performed, with 3270 being DIEP flaps for 2756 patients. DIEP flap failure was observed in 40 cases (1.22%). Bilateral reconstructions had a higher failure rate (2.31%) than unilateral (0.72%). The primary cause was intraoperative complications during flap harvest (18 cases), followed by insufficient arterial perfusion (seven cases). Other causes included postoperative hematoma (seven cases), venous congestion (six cases), and late-onset fat necrosis (two cases). Post-failure, five patients received a second free flap with three cases of repeated flap failure. Twenty patients received implant-based reconstruction with two cases of reconstruction failure, while seven patients received a pedicled latissimus dorsi (LD) flap reconstructions with no cases of reconstruction failure. Eight patients declined further reconstruction. CONCLUSION: A second free flap post-DIEP failure was associated with a high risk of reconstruction failure, suggesting the need for careful patient selection. Implant-based and pedicled LD flap seem to be reliable secondary reconstruction options.

Alternative Flap Options for Upper Extremity Reconstruction.

For major upper limb defects, a wide range of established pedicled and free flap options can be used. These include the latissimus dorsi/thoracodorsal artery perforator, lateral arm, posterior interosseous artery, rectus abdominis, gracilis, and anterolateral thigh flaps. Technical proficiency is essential, and favorable success rates in terms of functional and esthetic outcomes can be achieved. Herein, alternative flap options (both pedicled and free) are introduced and discussed through a few illustrative case examples.

DIEP Flap for Head and Neck Reconstruction: An Underutilized Option!

Background The deep inferior epigastric artery perforator (DIEP) flap is a workhorse flap for breast reconstruction. Its use for head and neck (HN) reconstruction is rare. Abdomen provides a donor site abundant in skin and subcutaneous tissue, amenable to primary closure; sizeable, robust, and consistent perforators and a long, sizeable pedicle for comfortable microvascular anastomosis. Its offers all the donor variables needed for HN reconstruction in abundance. Methods It is a quasiexperimental design study. DIEP flap use for HN reconstruction in our series was opportunistic, that is, when donor site matched the defect. Cases that had very thick thighs and lesser bulk in abdomen and cases that had very thin thighs but much more bulk in abdomen were considered for reconstruction using DIEP flap. Results The DIEP flap was done in 11 cases for HN reconstruction. There were two re-explorations during postoperative period: one flap loss and another had partial necrosis. Conclusion Abdomen is an excellent donor site option for HN reconstruction in selected cases, especially when harvested as a perforator flap.

Predesigned chimeric deep inferior epigastric perforator and inguinal lymph node flap for combined breast and lymphedema reconstruction: A comprehensive algorithmic approach.

The combined use of a deep inferior epigastric perforator (DIEP) flap coupled with vascularized inguinal lymph nodes (VILNs) for simultaneous breast and lymphedema reconstruction has already been well established, and promising results have been reported. However, a standardized approach for the planning and shaping of this combined flap is still lacking. We aimed to propose a comprehensive algorithmic approach for delayed unilateral breast and lymphedema reconstruction using a predesigned abdominal flap associated with inguinal lymph node transfer. We present in detail the preoperative measurements and surgical technique of the chimeric flap, which combines a predesigned DIEP template and a preselected inguinal lymph node flap, based on the preoperative computed tomography angiography and SPEC-CT findings, respectively; four different flap types are described according to the location of the pedicles of the two flap components. Our results of a series of 34 consecutive female patients with unilateral mastectomy and arm lymphedema, who underwent this combined predesigned reconstructive procedure, are retrospectively analyzed and reported. We recorded a high survival rate of the chimeric flaps in our series, with only one case of partial ischemic loss of a DIEP skin island. In the majority of our patients, the pedicles of the combined flaps were located in opposite positions. After a mean 35-month follow-up, we recorded a 47% mean volume difference reduction of the lymphedematous compared to the unaffected arm; no donor-site lymphedema was documented. Self-evaluation questionnaires showed high patient satisfaction rates regarding breast reconstruction. This algorithmic approach provides standardized guidance for accurate design and transfer of the DIEP-VILN chimeric flap while achieving highly satisfactory outcomes for both breast and lymphedema reconstruction.

Challenges in Autologous Breast Reconstruction: A Review of Recommendations.

Breast reconstruction is an integral part of breast cancer treatment and offers significant psychosocial benefits for patients undergoing mastectomy as a part of their treatment plan. Autologous breast reconstruction (ABR) utilizes a patient's own tissue to reconstruct the mastectomy defect, obviating the need for the implantation of a foreign object. As the field of plastic surgery progresses, ABR has become an excellent option for the recreation of a native breast mount. With that said, there are patient populations who present unique challenges when optimizing an aesthetic ABR result. We aim to discuss these challenging groups, including patients with both high and low body mass index (BMI), patients with a history of massive weight loss, patients who require post-mastectomy radiation therapy (PMRT), and patients electing for unilateral procedures where the surgeon attempts to match the reconstructed breast with the native breast. In our discussion, we review the literature recommendations for management as well as our experiences with our own patient cases. Ultimately, we believe this procedure can be performed in a wide variety of patient types and can be offered to those who may not be considered the "ideal" candidate.

The efficacy of sensory nerve coaptation in DIEP flap breast reconstruction - Preliminary results of a double-blind randomized controlled trial.

BACKGROUND: Sensory nerve coaptation has great potential to restore sensation after autologous breast reconstruction. However, blinded and randomized studies are lacking. We therefore present the preliminary results of our ongoing double-blinded randomized controlled trial that compares sensory recovery of innervated versus non-innervated DIEP flaps. METHODS: Patients who underwent DIEP flap breast reconstruction between July 2019 and February 2022 were included and randomized. The anterior cutaneous branch of the second or third intercostal nerve was coapted. Pre- and postoperative sensory testing was performed with Semmes-Weinstein Monofilaments, Pressure Specified Sensory Device, and a thermostimulator, for tactile and temperature thresholds. RESULTS: This interim analysis comprised 41 patients contributing 29 innervated and 38 non-innervated breasts. At 24 months of follow-up, the mean monofilament value of the flap skin was lower in innervated than in non-innervated flaps (4.48 vs. 5.20, p = 0.003). Touch thresholds were lower the center of the innervated flaps (47.8 vs. 71.2 g/mm2, p = 0.036), and heat pain was more often imperceptible in non-innervated flaps (42.1% vs. 10.3%, p = 0.004). No adverse events were associated with sensory nerve coaptation. CONCLUSIONS: These preliminary results indicate superior sensibility and recovery of protective sensation in innervated compared with non-innervated DIEP flaps. Although the results of the completed trial must be awaited to establish the full clinical impact, including highly anticipated quality of life outcomes, we encourage continuation of scientific and clinical efforts in this promising technique.

Beyond the Breast: Body Contouring in the Context of Abdominally Based Microsurgical Breast Reconstruction.

With continued advances in abdominally based microsurgical breast reconstruction, the operative goal is no longer the creation of a simple breast mound but rather the formation of an aesthetically pleasing breast. While a substantial body of work has been dedicated to accomplishing this result, a similar progression has yet to be reflected in the literature with regard to the contour and shape of the abdominal donor site. Operative advances including muscle, fascial, and nerve preservation have been effective in minimizing the physiologic donor site morbidity of this procedure but have focused less on its cosmesis. Additionally, the published techniques aimed at the aesthetics of the abdomen have focused on the initial procedure and have not utilized the multistage process of breast reconstruction. In this paper, we will describe our approach to optimize the aesthetic result of the abdomen in abdominally based microsurgical breast reconstruction.

MRA for Preoperative Planning and Postoperative Management of Perforator Flap Surgeries: A Review.

Perforator flap magnetic resonance angiography (MRA) has emerged as a widely accepted and preferred modality for perforator flap mapping at several institutions. Autologous perforator flaps are a type of reconstructive microsurgical technique that involves transferring skin and fat from one part of the patient's body to another to replace tissue lost due to trauma, cancer resection, or other reasons. Autologous perforator flaps are based on a specific perforating blood vessel perfusing the transferred tissue. Hence, the surgery relies on the precise identification and mapping of perforating vessels to ensure successful outcomes. With its superior soft tissue contrast and multiplanar imaging capabilities, MRA has shown great potential in providing accurate and detailed visualization of perforator anatomy, size, and course. This review article summarizes the current literature on perforator flap MRA, including its technical considerations, imaging protocols, postprocessing, and reporting, specifically for autologous breast reconstructions. The advantages and limitations of MRA in evaluating perforator flaps are discussed, including its role in preoperative planning, intraoperative guidance, and postoperative assessment. Anatomy, brief surgical technique, specific technical modifications, and reporting of most commonly performed autologous breast flaps are described. Recent advancements in Perforator flap surgery and MRA techniques are discussed. Additionally, we examine the emerging role of artificial intelligence and machine learning in improving the accuracy and efficiency of perforator flap MRA interpretation. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 5.

Pedicle stabilization with fibrin sealant in DIEP flap breast reconstruction.

Microsurgical procedures are nowadays routinely performed worldwide in reconstructive surgery. The deep inferior epigastric artery perforator (DIEP) flap has become the gold standard in breast reconstruction due to its excellent outcomes and lower donor site morbidity. However, complications, including flap failure, still occur in DIEP flap breast reconstruction. Often, according to our experience, these complications result from pedicle disorders, which can be attributed to postoperative mobilization. In the present study, we evaluated the efficacy and safety of using a fibrin sealant as a method for pedicle stabilization to prevent pedicle mobilization in the postoperative period. With our technique, after the flap insetting and microsurgical anastomosis, the pedicle was stabilized by applying a fibrin sealant (TISSEEL™) around and over the entire pedicle. Our study included a homogeneous series of 70 patients who received a delayed DIEP flap breast reconstruction. A retrospective study was conducted to evaluate this novel technique compared to the conventional method. In our experience, the fibrin glue allowed us to reduce the strain for correct pedicle positioning and all subsequent efforts to avoid displacements in the postoperative period. Our preliminary results suggest that this method may lead to a reduction in overall complications attributable to pedicle disorders.

A systematic review of the scientific evidence of venous supercharging in autologous breast reconstruction with abdominally based flaps.

BACKGROUND: Abdominally based free flaps are commonly used in breast reconstruction. A frequent complication is venous congestion, which might contribute to around 40% of flap failures. One way to deal with it is venous supercharging. The primary aim of this study was to investigate the scientific evidence for the effects of venous supercharging. METHODS: A systematic literature search was conducted in PubMed, CINAHL, Embase, and Cochrane library. The included articles were critically appraised, and certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. RESULTS: Thirty-six studies were included. Most studies had serious study limitations and problems with directness. Three studies report 'routine' use of venous supercharging and performed it prophylactically in patients who did not have clinical signs of venous congestion. Seventeen studies report on flap complications, of which one is a randomised controlled trial demonstrating statistically significant lower complication rates in the intervention group. The overall certainty of evidence for the effect of a venous supercharging on flap complications, length of hospital stay and operative time, in patients without clinical signs of venous congestion, is very low (GRADE ⊕ ⊕ ⊝ ⊝), and low on and surgical takebacks (GRADE ⊕ ⊕ ⊝ ⊝). Twenty-one studies presented data on strategies and overall certainty of evidence for using radiological findings, preoperative measurements, and clinical risk factors to make decisions on venous supercharging is very low (GRADE ⊕ ⊝ ⊝ ⊝). CONCLUSION: There is little scientific evidence for how to predict in which cases, without clinical signs of venous congestion, venous supercharging should be performed. The complication rate might be lower in patients in which a prophylactic venous anastomosis has been performed. TRIAL REGISTRATION: PROSPERO (CRD42022353591).

Colgajo DIEP pediculado para reconstrucción de úlceras isquiáticas y trocantéricas sin opción a colgajo local / DIEP pedicled flap for reconstruction of ischial and trochanteric ulcers without local flap option

Introducción y objetivo: El colgajo DIEP pediculado ofrece una alternativa reproducible en el manejo de úlceras isquiáticas y trocantéricas en las que no hay tejido sano periférico disponible para la realización de un colgajo local. Describimos la técnica quirúrgica y presentamos 2 casos clínicos en los que empleamos este procedimiento. Material y método: Previo rastreo con ultrasonido doppler de las arterias perforantes periumbilicales, trazamos una isla cutánea vertical de 10 x15 cm, disecamos el pedículo hasta la unión con la arteria epigástrica inferior profunda que disecamos lo más proximal posible. Realizamos un túnel subcutáneo hasta el área a tratar para el paso sin tensión del pedículo vascular y colocamos el colgajo en su área receptora, suturándolo en dos planos. Resultados: Describimos 2 casos en los que obtuvimos excelentes resultados funcionales con baja morbilidad del área donadora. Conclusiones: En nuestra experiencia, el colgajo DIEP pediculado fue una adecuada opción reconstructiva en pacientes con úlceras isquiáticas y trocantéricas en quienes los tejidos periféricos no permitían reconstrucción con colgajos locales, ya que presenta una baja morbilidad en la zona donadora y un pedículo relativamente largo que le permite alcanzar la zona del defecto.(AU)

Background and objective: The pedicled DIEP flap offers a reproducible alternative in the management of ischial and trochanteric ulcers where healthy peripheral tissue is not available for the realization of a local flap. We describe the surgical technique and present 2 clinical cases in which this procedure has been used, offering a reproducible alternative in the treatment of these conditions. Methods: A doppler ultrasound scan of the periumbilical perforating arteries is carried out, tracing a 10 x 15 cm vertical skin island. The pedicle is dissected down to the junction with the deep inferior epigastric artery, which is dissected as proximal as possible. A subcutaneous tunnel is made to the area to be treated for the passage without tension of the vascular pedicle and the flap is placed in its receiving area, suturing it in two planes. Results: We present 2 clinical cases in which we obtained excellent functional results and low morbidity in the donor area. Conclusions: In our experience, the pedicled DIEP flap was an adequate reconstructive option in patients with ischial and trochanteric ulcers in whom peripheral tissues do not allow reconstruction with local flaps, since it has low morbidity in the donor area and a relatively long pedicle that allows it to reach the defect area.(AU)

Dobutamine and Goal-Directed Fluid Therapy for Improving Tissue Oxygenation in Deep Inferior Epigastric Perforator (DIEP) Flap Breast Reconstruction Surgery: Protocol for a Randomized Controlled Trial.

BACKGROUND: Breast reconstruction is an integral part of breast cancer care. There are 2 main types of breast reconstruction: alloplastic (using implants) and autologous (using the patient's own tissue). The latter creates a more natural breast mound and avoids the 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 (eg, 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 guiding 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 and Health Canada approval, patients undergoing DIEP flap surgery are randomly assigned to receive CO monitoring for the 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 reanastomosis of the DIEP flap. Low dose (2.5 µg/kg/hr) dobutamine infusion continues for up to 4 hours postoperatively, provided there are no associated complications (ie, 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 the study recruitment was interrupted by the COVID-19 pandemic. As of October 4, 2023, 34 participants have been recruited. Because of the significant delays associated 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 from participating 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 reduce complications following DIEP flap breast reconstruction surgery. However, given that the 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. TRIAL REGISTRATION: Clinicaltrials.gov NCT04020172; https://clinicaltrials.gov/study/NCT04020172.