Editor | Prof. Dr. V. Bonhomme CO-Editors | Dr. Y. Kremer — Prof. Dr. M. Van de Velde ACTA ANAESTHESIOLOGICA JOURNAL OF THE BELGIAN SOCIETY OF ANESTHESIOLOGY, RESUSCITATION, PERIOPERATIVE MEDICINE AND PAIN MANAGEMENT (BeSARPP) BELGICA Indexed in EMBASE l EXCERPTA MEDICA ISSN: 2736-5239 Suppl. 1 202071 Master Theses www.besarpp.be Cover-1 -71/suppl.indd 1 12/01/2021 12:37 ACTA ANÆSTHESIOLOGICA BELGICA 2020 – 71 – Supplement 1 EDITORS Editor-in-chief : Vincent Bonhomme, CHU Liège, av. de l’Hôpital 1, B-4000 Liège Co-Editors : Marc Van de Velde, KU Leuven, Herestraat 49, B-3000 Leuven Yves Kremer, CU Saint-Luc, av. Hippocrate, B-1200 Woluwe-Saint-Lambert Associate Editors : Margaretha Breebaart, UZA, Wilrijkstraat 10, B-2650 Edegem Christian Verborgh, UZ Brussel, Laarbeeklaan 101, B-1090 Jette Fernande Lois, CHU Liège, av. de l’Hôpital 1, B-4000 Liège Annelies Moerman, UZ Gent, C. Heymanslaan 10, B-9000 Gent Mona Monemi, CU Saint-Luc, av. 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Phone : +32 4 321 7117 ; Email : [email protected] erratum2014(2).indd 2 4/08/14 14:04 Cover-2-Suppl.2020-nieuw kopie.indd 1 12/01/2021 12:38 (Acta Anaesth. Belg., 2020, 71, 1-6) Near-infrared spectroscopy for monitoring tissue oxygenation in breast reconstruction E. THYS (*), J. DE PUYDT (*), F. THIESSEN (*), T. TONDU (**), V. SALDIEN (*) Abstract : Background : A breast reconstruction with a monly performed after mastectomies. The success deep inferior epigastric artery perforator flap (DIEP-flap) ratio of this type of surgery is high, more than 95 %. is commonly performed microvasculared procedure. It Nevertheless, a free flap failure can occur (1). The flap can is crucial to detect vascular complications as early as be jeopardized by vascular complications, which usually possible to maximize the chance on a successful flap occur in the first hours after surgery (2). The survival of revision. Near-infrared spectroscopy (NIRS) measures the free flap depends on the continuous arterial inflow the tissue oxygen saturation (StO2), by using infrared and the venous outflow through the new microvascular light and can be an interesting tool to monitor flap anastomoses. Thrombosis, vasospasm, kinking of the perfusion. vessels or external compression on blood vessels can Objective : The aim of this study is to determine whether cause ischemia of the flap. It is essential to recognize NIRS is suitable to assess tissue perfusion after DIEP- these complications as early as possible to maximize flap reconstruction. successful flap revision. Ischemia of the flap can become Methods : The trial was designed as a single cohort irreversible due to the no-reflow phenomenon (1). The interventional pilot study (approved by the Ethics key to enhance the flap success rate is early detection of Committee of the University Hospital of Antwerp - complications. Internal reference number : 18/12/173 ; Belgian regis- A DIEP-flap is commonly used to perform an tration number : B300201836129). autologous breast reconstruction. It uses tissue from All patients scheduled for uni- or bilateral breast the lower abdominal wall to reconstruct the breast. The reconstruction by means of a DIEP-flap were included, deep inferior epigastric artery and vein are responsible if no exclusion criteria were present. The StO2 was for the regional perfusion of the skin and subcutaneous measured during the first 12 hours postoperatively. The fatty tissue below the umbilicus and above the pubic StO2 measurements were performed using a sensor area. In the first phase, the plastic surgeon dissects the positioned on the free flap and one on the native tissue. flap. In a second phase, the vessels are microsurgically Results : Twelve women underwent a uni- or bilateral anastomosed to the internal mammary artery and vein. It DIEP-flap breast reconstruction. In this study, the mean only uses skin and subcutaneous fatty tissue. The muscles StO2 values of the flap and of the native tissue were 90.16 of the abdomen are left unaffected (3). ± 4.63 % (mean ± SD) and 91.52 ± 2.23 % (mean ± SD), Clinical examination is still the gold standard for respectively. The mean difference in StO2 mea urements flap monitoring. Skin color, temperature and Doppler between the free flap and the native tissue was 1.36 ± signals are frequently examined (4). Clinical monitoring 3.46 % (mean ± SD). This difference was not statistically is subjective, intermittent, labor intensive and requires significant, according to the Wilcoxon signed-ranks test. experience. There is also a time delay between the In one patient, the StO2 value of the free flap tissue had occurrence of vascular problems and the clinical signs fallen to 52%, due to a hematoma. The patient underwent (2). Because of these disadvantages, a more objective a successful re-exploration of the free flap. and continuous method is desirable. Conclusion : Our data showed that NIRS is an easy, tissue-specific, objective and sensitive way to monitor Ellen THYS, MD ; Joris DE PUYDT, MD ; Filip THIESSEN, MD ; tissue oxygenation in a continuous manner, after free flap Thierry TONDU, MD ; Vera SALIDEN, MD, PhD breast reconstructions. (*) Department of Anesthesiology, University Hospital Ant- werp, 2650 Edegem, Belgium (**) Plastic Surgery Unit, University Hospital Antwerp, 2650 Keywords : Breast reconstruction ; oximetry ; Near Edegem, Belgium infrared spectroscopy ; non-invasive monitoring. Corresponding author : Department of Anesthesiology, Uni- versity Hospital Antwerp, Wilrijkstraat 10, 2650 Edegem, Belgium. E-mail : [email protected] INTRODUCTION Paper submitted on Mar 13, 2020 and accepted on May 26, Breast reconstructions with deep inferior epigastric 2020. artery and vein perforator flaps (DIEP-flaps) are com- Conflict of interest : none. © Acta Anæsthesiologica Belgica, 2020, 71, Spplement 1 01-Thys.indd 1 12/01/2021 12:08 2 E. THYS et al. Near-infrared spectroscopy (NIRS) is an easy-to- use, continuous, objective and noninvasive method. It provides real-time information about oxygen delivery. NIRS was first described in 1977 (5). NIRS uses infrared light waves to detect oxygen content of tissue. Near- Fig. 1. – Study design. a. NIRS in unilateral DIEP-flap infrared light waves are used to measure the level of breast reconstruction ; b. NIRS in bilateral DIEP-flap breast oxygen the hemoglobin of the tissue contains (= tissue reconstruction. oxygen saturation, StO2). The tissue oxygen saturation (StO2) measurements are based on the principles of received verbal and written information about this study optical spectrometry and the law of Lambert-Beer. during the preoperative consultation. If no exclusion Infrared light of five different wavelengths is emitted on criteria were present, the patients were included in our the flap. The flap reflects a part of the light waves on two study. The study design is illustrated in figure 1. ® ® detectors. These detectors measure the StO2. It reflects the In our study, the Foresight device and the Foresight microperfusion and the oxygen consumption in the free pediatric sensors (CASMED, Brandford, CT, USA) were flap. Changes in blood pressure and the supplementation used. The StO2 measurement depth is determined by the of oxygen to the patient influence the results (6). NIRS distance between the emitting and receiving source. The can detect ischemia and hypoxia. The continuous data Foresight® pediatric sensors infrared light penetrates up are a quantitative and objective parameter to evaluate to a depth of 0.75 to 2 cm in the tissue. The width of the tissue oxygenation. The method is currently used to measurement is 4 cm. The near infrared light consists of detect cerebral and regional tissue ischemia (7-12) during five different wavelengths (690, 730, 770, 810 and 870 multiple surgical procedures ; cardiac surgery, carotid nm). An algorithm analyzes the reflected light waves. endarterectomy, the detection of ischemia in shock, the Demographic patient details (age, body mass detection of compartment syndrome, pediatrics, etc. (10, index, diabetes mellitus, cardiovascular comorbidities, 13). substance abuse, ASA score, hemoglobin) were obtained During plastic surgery, NIRS has been used as an from the digital patient record. early predictor of vascular complications (14, 15). But Anesthesia was performed according to the there still is a lack of information about the predictability standard of care treatment and adapted to provide of data provided by Foresight® in monitoring of free optimal flap perfusion. The patients received analgesia, flaps. The technology is easy to use and inexpensive. It vasodilators and fluid titrated on an individual basis. does not harm the patient or the free flap. During surgery heart rate, non-invasive and invasive blood pressure, pulse oxygen saturation, temperature, METHODOLOGY respiratory rate, operation time and adverse events (need for blood transfusion or inotropic medication, pulse Our trial was designed as a single cohort oxygen desaturation <90 % or allergic/anaphylactic interventional pilot study. The study was conducted reaction) were recorded. with the approval of the Ethics Committee of the The self-adherent disposable Foresight® sensors University Hospital of Antwerp (Internal reference were placed in the center of the free flap on a surface number : 18/12/173 ; Belgian registration number : area of 16 cm², at the end of the surgery. Another sensor B300201836129).