Spectral characterization of intraoperative renal perfusion using hyperspectral imaging and artificial intelligence

Accurate intraoperative assessment of organ perfusion is a pivotal determinant in preserving organ function e.g. during kidney surgery including partial nephrectomy or kidney transplantation. Hyperspectral imaging (HSI) has great potential to objectively describe and quantify this perfusion as opposed to conventional surrogate techniques such as ultrasound flowmeter, indocyanine green or the subjective eye of the surgeon. An established live porcine model under general anesthesia received median laparotomy and renal mobilization. Different scenarios that were measured using HSI were (1) complete, (2) gradual and (3) partial malperfusion. The differences in spectral reflectance as well as HSI oxygenation (StO2) between different perfusion states were compelling and as high as 56.9% with 70.3% (± 11.0%) for "physiological" vs. 13.4% (± 3.1%) for "venous congestion". A machine learning (ML) algorithm was able to distinguish between these perfusion states with a balanced prediction accuracy of 97.8%. Data from this porcine study including 1300 recordings across 57 individuals was compared to a human dataset of 104 recordings across 17 individuals suggesting clinical transferability. Therefore, HSI is a highly promising tool for intraoperative microvascular evaluation of perfusion states with great advantages over existing surrogate techniques. Clinical trials are required to prove patient benefit.

Crystalloid volume versus catecholamines for management of hemorrhagic shock during esophagectomy - assessment of microcirculatory tissue oxygenation of the gastric conduit in a porcine model using hyperspectral imaging - an experimental study

INTRODUCTION

Oncologic esophagectomy is a two-cavity procedure with considerable morbidity and mortality. Complex anatomy and the proximity to major vessels constitute a risk for massive intraoperative hemorrhage. Currently, there is no conclusive consensus on the ideal anesthesiologic countermeasure in case of such immense blood loss. The objective of this work was to identify the most promising anesthesiologic management in case of intraoperative hemorrhage with regards to tissue perfusion of the gastric conduit during esophagectomy using hyperspectral imaging (HSI).

MATERIAL AND METHODS

An established live porcine model (n=32) for esophagectomy was used with gastric conduit formation and simulation of a linear stapled side-to-side esophagogastrostomy. After a standardized procedure of controlled blood loss of about 1 L per pig, the four experimental groups (n=8 each) differed in anesthesiologic intervention i.e. (I) permissive hypotension, (II) catecholamine therapy using noradrenaline, (III) crystalloid volume supplementation and (IV) combined crystalloid volume supplementation with noradrenaline therapy. HSI tissue oxygenation (StO2) of the gastric conduit was evaluated and correlated with systemic perfusion parameters. Measurements were conducted before (T0) and after (T1) laparotomy, after hemorrhage (T2) and 60 minutes (T3) and 120 minutes (T4) after anesthesiologic intervention.

RESULTS

StO2 values of the gastric conduit showed significantly different results between the four experimental groups with 63.3% (±7.6%) after permissive hypotension (I), 45.9% (±6.4%) after catecholamine therapy (II), 70.5% (±6.1%) after crystalloid volume supplementation (III) and 69.0% (±3.7%) after combined therapy (IV). StO2 values correlated strongly with systemic lactate values (r=-0.67; CI -0.77 to -0.54), which is an established prognostic factor.

CONCLUSION

Crystalloid volume supplementation (III) yields the highest StO2 values and lowest systemic lactate values and therefore appears to be the superior primary treatment strategy after hemorrhage during esophagectomy with regards to microcirculatory tissue oxygenation of the gastric conduit.

Optimization of anastomotic technique and gastric conduit perfusion with hyperspectral imaging and machine learning in an experimental model for minimally invasive esophagectomy

INTRODUCTION

Esophagectomy is the mainstay of esophageal cancer treatment, but anastomotic insufficiency related morbidity and mortality remain challenging for patient outcome. Therefore, the objective of this work was to optimize anastomotic technique and gastric conduit perfusion with hyperspectral imaging (HSI) for total minimally invasive esophagectomy (MIE) with linear stapled anastomosis.

MATERIAL AND METHODS

A live porcine model (n = 58) for MIE was used with gastric conduit formation and simulation of linear stapled side-to-side esophagogastrostomy. Four main experimental groups differed in stapling length (3 vs. 6 cm) and simulation of anastomotic position on the conduit (cranial vs. caudal). Tissue oxygenation around the anastomotic simulation site was evaluated using HSI and was validated with histopathology.

RESULTS

The tissue oxygenation (ΔStO₂) after the anastomotic simulation remained constant only for the short stapler in caudal position (-0.4 ± 4.4%, n.s.) while it was impaired markedly in the other groups (short-cranial: -15.6 ± 11.5%, p = 0.0002; long-cranial: -20.4 ± 7.6%, p = 0.0126; long-caudal: -16.1 ± 9.4%, p < 0.0001). Tissue samples from avascular stomach as measured by HSI showed correspondent eosinophilic pre-necrotic changes in 35.7 ± 9.7% of the surface area.

CONCLUSION

Tissue oxygenation at the site of anastomotic simulation of the gastric conduit during MIE is influenced by stapling technique. Optimal oxygenation was achieved with a short stapler (3 cm) and sufficient distance of the simulated anastomosis to the cranial end of the gastric conduit. HSI tissue deoxygenation corresponded to histopathologic necrotic tissue changes. The experimental model with HSI and ML allow for systematic optimization of gastric conduit perfusion and anastomotic technique while clinical translation will have to be proven.

Robotic colorectal resection in combination with a multimodal enhanced recovery program - results of the first 100 cases

PURPOSE

In Germany, colorectal robot-assisted surgery (RAS) has found its way and is currently used as primary technique in colorectal resections at our clinic. We investigated whether RAS can be extensively combined with enhanced recovery after surgery (ERAS®) in a large prospective patient group.

METHODS

Using the DaVinci Xi surgical robot, all colorectal RAS from 09/2020 to 01/2022 were incorporated into our ERAS® program. Perioperative data were prospectively recorded using a data documentation system. The extent of resection, duration of the operation, intraoperative blood loss, conversion rate, and postoperative short-term results were analyzed. We documented the postoperative duration of Intermediate Care Unit (IMC) stay and major and minor complications according to the Clavien-Dindo classification, anastomotic leak rate, reoperation rate, hospital-stay length, and ERAS® guideline adherence.

RESULTS

One hundred patients (65 colon and 35 rectal resections) were included (median age: 69 years). The median durations of surgery were 167 min (colon resection) and 246 min (rectal resection). Postoperatively, four patients were IMC-treated (median stay: 1 day). In 92.5% of the colon and 88.6% of the rectum resections, no or minor complications occurred postoperatively. The anastomotic leak rate was 3.1% in colon and 5.7% in rectal resection. The reoperation rate was 7.7% (colon resection) and 11.4% (rectal resection). The hospital stay length was 5 days (colon resection) and 6.5 days (rectal resection). The ERAS® guideline adherence rate was 88% (colon resection) and 82.6% (rectal resection).

CONCLUSION

Patient perioperative therapy per the multimodal ERAS® concept is possible without any problems in colorectal RAS, leading to low morbidity and short hospital stays.

Thrombotischer Verschluss der extrakorporalen Zirkulation während hepatischer Chemosaturation trotz zielgerechter Antikoagulation

Die perkutane hepatische Chemosaturation ist eine Behandlungsoption bei nichtresektablen primären oder sekundären Lebertumoren. Dabei wird der Bereich der Lebervenenmündung der Vena cava inferior (VCI) mittels 2 Ballons von der Zirkulation isoliert, sodass die systemische Verteilung des über die Leberarterie applizierten Chemotherapeutikums Melphalan verhindert wird. Nach Passage der Leber und venöser Drainage aus der retrohepatischen VCI durchläuft das chemosaturierte Blut 2 parallel geschaltete extrakorporale Filter. Anschließend wird das gereinigte Blut jugulär rückgeführt. Das Verfahren geht oft mit einer ausgeprägten hämodynamischen Instabilität einher, deren Ursache nicht abschließend geklärt ist. Zusätzlich stellt das Gerinnungsmanagement eine Herausforderung dar. Die Autoren berichten von einem Fall, bei dem sich trotz ausreichender „activated clotting time“ (ACT) ein Thrombus im rückführenden Schenkel der extrakorporalen Zirkulation bildete. Gezielte Problemsuche und -lösung waren parallel zur hämodynamischen Stabilisierung und interdisziplinären Zusammenarbeit notwendig, um die Intervention erfolgreich durchzuführen und der Patientin eine sichere Therapie zukommen zu lassen.

When to operate after SARS-CoV-2 infection? A review on the recent consensus recommendation of the DGC/BDC and the DGAI/BDA

Since the eruption of the worldwide SARS-CoV-2 pandemic in late 2019/early 2020, multiple elective surgical interventions were postponed. Through pandemic measures, elective operation capacities were reduced in favour of intensive care treatment for critically ill SARS-CoV-2 patients. Although intermittent low-incidence infection rates allowed an increase in elective surgery, surgeons have to include long-term pulmonary and extrapulmonary complications of SARS-CoV-2 infections (especially "Long Covid") in their perioperative management considerations and risk assessment procedures. This review summarizes recent consensus statements and recommendations regarding the timepoint for surgical intervention after SARS-CoV-2 infection released by respective German societies and professional representatives including DGC/BDC (Germany Society of Surgery/Professional Association of German Surgeons e.V.) and DGAI/BDA (Germany Society of Anesthesiology and Intensive Care Medicine/Professional Association of German Anesthesiologists e.V.) within the scope of the recent literature. The current literature reveals that patients with pre- and perioperative SARS-CoV-2 infection have a dramatically deteriorated postoperative outcome. Thereby, perioperative mortality is mainly caused by pulmonary and thromboembolic complications. Notably, perioperative mortality decreases to normal values over time depending on the duration of SARS-CoV-2 infection.

Maternal and Child Health Pipeline Training Programs: A Description of Training Across 6 Funded Programs

Purpose

The HRSA-funded maternal and child health pipeline training programs (MCHPTPs) are a response to the critical need to diversify the MCH workforce, as a strategy to reduce health disparities in MCH populations. These MCHPTPs support students from undergraduate to graduate education and ultimately into the MCH workforce.

Description

The models and components of training across the six MCHPTPs funded in 2016–2021 are summarized, to examine the design and delivery of undergraduate pipeline training and the insights gained across programs.

Assessment

Strategies that emerged across training programs were organized into three themes: recruitment, support for student persistence (in education), and pipeline-to-workforce intentionality. Support for student persistence included financial support, mentoring, creating opportunity for students to develop a sense of belonging, and the use of research as a tool to promote learning and competitiveness for graduate education. Finally, the link to Maternal and Child Health Bureau (MCHB) long-term training and other MCHB opportunities for professional development contributed significant nuance to the pipeline-to-workforce objectives of these programs.

Conclusions

The MCHPTPs not only increase the diversity of the MCH workforce, they also actively prepare the next generation of MCH leaders. The intentional connection of undergraduates to the infrastructure and continuum of MCH training, underscores the comprehensive impact of this funding.

[First 18 months as certified ERAS® center for colorectal cancer : Lessons learned and results of the first 261 patients]

BACKGROUND

Enhanced recovery after surgery (ERAS®) describes a multimodal, interdisciplinary and interprofessional treatment concept that optimizes the postoperative convalescence of the patient through the use of evidence-based measures.

GOAL OF THE WORK

The aim of this article is to present the experiences of our center certified by the ERAS® Society for colorectal resections 18 months after successful implementation.

MATERIAL AND METHODS

Since the beginning of the certification 261 patients have been treated in our clinic according to the specifications of the ERAS® concept. As a comparison group the last 50 patients prior to implementation were evaluated in terms of compliance with ERAS® requirements, length of hospital stay and readmission rate, the need for care in an intensive or intermediate care ward, the number of necessary reoperations and the complication rate.

RESULTS

Compliance increased from 39.3% preERAS® to 81.1% after ERAS® implementation (p < 0.001). At the same time the length of stay of ERAS® patients was reduced from 7 days to 5 days (p = 0.001). While the rate of surgical complications was the same between the two groups (p = 0.236), nonsurgical complications occurred significantly less frequently in the ERAS® cohort (p = 0.018).

DISCUSSION

There are well-known stumbling blocks in implementing and maintaining an ERAS® concept; however, it is worthwhile for the patient to circumnavigate this and establish ERAS® as the standard treatment path.

Bedside hyperspectral imaging indicates a microcirculatory sepsis pattern - an observational study

INTRODUCTION

Microcirculatory alterations are key mechanisms in sepsis pathophysiology leading to tissue hypoxia, edema formation, and organ dysfunction. Hyperspectral imaging (HSI) is an emerging imaging technology that uses tissue-light interactions to evaluate biochemical tissue characteristics including tissue oxygenation, hemoglobin content and water content. Currently, clinical data for HSI technologies in critical ill patients are still limited.

METHODS AND ANALYSIS

TIVITA® Tissue System was used to measure Tissue oxygenation (StO2), Tissue Hemoglobin Index (THI), Near Infrared Perfusion Index (NPI) and Tissue Water Index (TWI) in 25 healthy volunteers and 25 septic patients. HSI measurement sites were the palm, the fingertip, and a suprapatellar knee area. Septic patients were evaluated on admission to the ICU (E), 6 h afterwards (E+6) and three times a day (t3-t9) within a total observation period of 72 h. Primary outcome was the correlation of HSI results with daily SOFA-scores.

RESULTS

Serial HSI at the three measurement sites in healthy volunteers showed a low mean variance expressing high retest reliability. HSI at E demonstrated significantly lower StO2 and NPI as well as higher TWI at the palm and fingertip in septic patients compared to healthy volunteers. StO2 and TWI showed corresponding results at the suprapatellar knee area. In septic patients, palm and fingertip THI identified survivors (E-t4) and revealed predictivity for 28-day mortality (E). Fingertip StO2 and THI correlated to SOFA-score on day 2. TWI was consistently increased in relation to the TWI range of healthy controls during the observation time. Palm TWI correlated positively with SOFA scores on day 3.

DISCUSSION

HSI results in septic patients point to a distinctive microcirculatory pattern indicative of reduced skin oxygenation and perfusion quality combined with increased blood pooling and tissue water content. THI might possess risk-stratification properties and TWI could allow tissue edema evaluation in critically ill patients.

CONCLUSION

HSI technologies could open new perspectives in microcirculatory monitoring by visualizing oxygenation and perfusion quality combined with tissue water content in critically ill patients - a prerequisite for future tissue perfusion guided therapy concepts in intensive care medicine.

[Perioperative fluid management in major abdominal surgery]

Intravascular fluid administration belongs to the cornerstones of perioperative treatment with a substantial impact on surgical outcome especially with respect to major abdominal surgery. By avoidance of hypovolemia and hypervolemia, adequate perioperative fluid management significantly contributes to the reduction of insufficient tissue perfusion as a determinant of postoperative morbidity and mortality. The effective use of intravascular fluids requires detailed knowledge of the substances as well as measures to guide fluid therapy. Fluid management already starts preoperatively and should be continued in the postoperative setting (recovery room, peripheral ward) considering a patient-adjusted and surgery-adjusted hemodynamic monitoring. Communication between all team members participating in perioperative care is essential to optimize fluid management.