Predicting Mortality Prior to Interhospital Hospital for "Unseen" General Surgery Patients: Development, Validation and Feasibility Trial of a Mortality Risk Calculator.

OBJECTIVE: Develop and validate a mortality risk calculator that could be utilized at the time of transfer, leveraging routinely collected variables that could be obtained by trained non-clinical transfer personnel. SUMMARY BACKGROUND DATA: There are no objective tools to predict mortality at the time of inter-hospital transfer for Emergency General Surgery (EGS) patients that are "unseen" by the accepting system. METHODS: Patients transferred to general or colorectal surgery services from January 2016 through August 2022 were retrospectively identified and randomly divided into training and validation cohorts (3:1 ratio). The primary outcome was admission-related mortality, defined as death during the index admission or within 30 days post-discharge. Multiple predictive models were developed and validated. RESULTS: Among 4,664 transferred patients, 280 (6.0%) experienced mortality. Predictive models were generated utilizing 19 routinely collected variables; the penalized regression model was selected over other models due to excellent performance using only 12 variables. The model performance on the validating set resulted in an area under the receiver operating characteristic curve, sensitivity, specificity, and balanced accuracy of 0.851, 0.90, 0.67, and 0.79, respectively. After bias correction, Brier score was 0.04, indicating a strong association between the assigned risk and the observed frequency of mortality. CONCLUSION: A risk calculator using twelve variables has excellent predictive ability for mortality at the time of interhospital transfer among "unseen" EGS patients. Quantifying a patient's mortality risk at the time of transfer could improve patient triage, bed and resource allocation, and standardize care.

Tumor Size Combined With CA-19 Level Improves Prediction of Survival of Patients With Pancreatic Adenocarcinoma Undergoing Perioperative Chemotherapy and Resection.

BACKGROUND AND OBJECTIVE: Five-year survival in pancreatic adenocarcinoma is less than 20%. While previous studies have postulated that a carbohydrate antigen 19-9 (CA19-9) threshold could predict outcome of resection, the role for CA19-9 in decision-making remains unclear. This study aims to assess whether CA19-9 levels combined with tumor size improve prediction of post-resection survival. METHOD: A retrospective analysis was conducted on 109 patients with pancreatic adenocarcinoma who underwent perioperative chemotherapy followed by resection. The primary outcome of mortality was, divided into short (<1 year) or prolonged (>2 years). Univariate and multivariable analyses compared the tumor size-adjusted CA19-9 between the outcome groups. RESULTS: Twenty-seven (24.78%) and eighty-two (75.23%) patients were in the short survival and prolonged-survival groups, respectively. The mean CA19-9 was significantly greater in the short vs prolonged group (P < .001). Analyzing CA19-9 level by tumor size, the association of high CA19-9 and short survival was significant for small (≤2 cm) and large tumor (>4 cm), but not for intermediate-size tumors (2-4 cm). Adjusting for preoperative variable did not change this association. CONCLUSION: CA 19-9 in combination with tumor size better identifies patients with prolonged post-resection survival. This prediction is most accurate in patients with either small (≤2 cms) or large (>4 cms) tumors compared to intermediate-size tumors.

Orthotopic forelimb transplantation in a Yucatan minipig model: Anatomic and in vivo study.

INTRODUCTION: Above elbow transplants represent 19% of the upper extremity transplants. Previous large-animal models have been too distal or heterotopic, did not use immunosuppression and had short survival. We hypothesize that an orthotopic forelimb transplant model, under standard immunosuppression, is feasible and can be used to address questions on peri-transplant ischemia reperfusion injury, and post-transplantation vascular, immunologic, infectious, and functional outcomes. MATERIALS AND METHODS: Four forelimbs were used for anatomical studies. Four mock transplants were performed to establish technique/level of muscle/tendon repairs. Four donor and four recipient female Yucatan minipigs were utilized for in-vivo transplants (endpoint 90-days). Forelimbs were amputated at the midarm and preserved through ex vivo normothermic perfusion (EVNP) utilizing an RBC-based perfusate. Hourly perfusate fluid-dynamics, gases, electrolytes were recorded. Contractility during EVNLP was graded hourly using the Medical Research Council scale. EVNP termination criteria included systolic arterial pressure ≥115 mmHg, compartment pressure ≥30 mmHg (at EVNP endpoint), oxygen saturation reduction of 20%, and weight change ≥2%. Indocyanine green (ICG) angiography was performed after revascularization. Limb rejection was evaluated clinically (rash, edema, temperature), and histologically (BANFF classification) collecting per cause and protocol biopsies (POD 1, 7, 30, 60 and endpoint). Systemic infections were assessed by blood culture and tissue histology. CT scan was used to confirm bone bridging at endpoint. RESULTS: Animals 2, 4 reached endpoint with grade 0-I rejection. Limbs 1, 3 presented grade III rejection on days 6, 61. CsA troughs averaged 461 ± 189 ng/mL. EVNLP averaged 4.3 ± 0.52 h. Perfusate lactate, PO2 , and pH were 5.6 ± 0.9 mmol/L, 557 ± 72 mmHg and 7.5 ± 0.1, respectively. Muscle contractions were 4 [1] during EVNLP. Transplants 2, 3, 4 showed bone bridging on CT. CONCLUSION: We present preliminary evidence supporting the feasibility of an orthotopic, mid-humeral forelimb allotransplantation model under standard immunosuppression regimen. Further research should validate the immunological, infectious, and functional outcomes of this model.

Upper Extremity Infections in the Transplant Population.

PURPOSE: As the duration of lifetime survival after organ transplantation continues to increase, the consequences of long-term immunosuppression, such as opportunistic and rare infections, are a high-risk reality. This study examined upper extremity infections in the transplant population to determine the current clinical risk profile, management, and outcomes. METHODS: An institutional database of 16,640 patients who underwent transplantation was queried for upper extremity infections from 2005 to 2017, defined as the presence of infection from the shoulder to the fingertips. The resulting data were analyzed using multivariable linear and logistic regression modeling. RESULTS: A total of 230 eligible patients experienced upper extremity infections at a mean age of 54.1 ± 15.3 years, occurring, on average, 7.9 ± 8.6 years after transplantation. The most commonly transplanted organ was the kidney (51.3%), followed by the liver (20%). The most common location of infection was the forearm (31.7%), digits (27.4%), and upper arm (17%). The most common types of infection were cellulitis (69.1%), abscess (33.5%), joint sepsis (6.5%), infectious tenosynovitis (3.9%), and osteomyelitis (1.3%). Patients taking an antifungal medication, those who had a joint infection, or those who had undergone lung transplantation had an approximately 2.5-day longer stay in the hospital. For every 1-year increase in age at the time of transplantation, the time from transplantation to infection decreased by 0.21 years. Those who had undergone bone marrow transplantation or those who were taking tacrolimus were expected to have approximately 8- and 6-year decreases, respectively, in the time from transplantation to infection. CONCLUSIONS: Upper extremity infections should be individually evaluated and treated because of the heterogeneity of transplant type, immunosuppression medications, the age of the patient, and infection characteristics. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

How much narcotics are really needed after bariatric surgery: results of a prospective study.

BACKGROUND: To mitigate the opioid crisis, physicians are reevaluating opioid prescribing patterns. OBJECTIVES: To evaluate outcomes of maximal opioid reduction on top of an existing Enhanced Recovery after Surgery (ERAS) pathway in our The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program-accredited bariatric surgery program. SETTING: Academic tertiary care hospital, United States. METHODS: Patients undergoing primary bariatric operation were studied from July 2017 to April 2019, (standard ERAS cohort), and compared to patients from April 2019 to February 2021 (standard ERAS with Sparing Opioid Use Postoperatively protocol) (SOUP cohort). The primary endpoint was reduction of perioperative opioid use. RESULTS: Of 367 patients, 212 (57.8%) and 155 (42.2%) were in the ERAS and SOUP cohorts, respectively. Roux-en-Y gastric bypass was 48.6% (n = 103) versus 54.2% (n = 84) and sleeve gastrectomy was 51.4% (n = 109) versus 45.8% (n = 71) for ERAS versus SOUP, respectively (P = .29). The SOUP cohort of patients required a low median inpatient morphine equivalent dose of 4 mg [0-6.2]. The ERAS cohort was discharged on a higher morphine equivalent dose than the SOUP cohort at 186.7 mg ± 92.9 versus 37.6 ± 32.3 (P < .05), and median consumption of the standard 5 mg oxycodone tablet was 1.5 tablets [0-4]. The SOUP cohort patients rated their pain satisfaction score on a scale of 1 to 10 at 9.1 points (standard deviation ± 1.8). The SOUP cohort had a shorter length of stay (P < .05), with comparable readmission rates. CONCLUSIONS: An opioid-sparing protocol can be implemented after bariatric surgery with high overall satisfaction with pain control.

Long term assessment of antibiotic prophylaxis and biliary microbiome in pancreaticoduodenectomy.

INTRODUCTION: Surgical site infections (SSI) can represent a major complication of pancreaticoduodenectomy (PD). We summarize the outcomes of process improvement efforts to reduce the SSI rates in PD that includes replacing Cefazolin with Ceftriaxone-Metronidazole as antibiotic prophylaxis. Additional efforts included current assessment of biliary microbiome and potential prophylactic failures based on bile cultures and suspected antibiotic allergies. METHOD: A single-center review of PD patients from January-2012 to March-2021. Study groups were divided into Pre and Post May-2015 (Group 1 and 2, respectively) when Ceftriaxone-Metronidazole prophylaxis and routine intraoperative cultures were standardized. Univariate and multivariable analyses were conducted to assess groups' differences and association with SSI. RESULTS: Six hundred ninety patients identified [267(38.7%) and 423(61.3%) in Group 1 and Group2, respectively]. After antibiotic change, SSI rates decreased from 28.1% to 16.5% (incisional: 17.6%-7.5%, organ-space or abscess: 17.2%-13.0%), Group 1 and Group 2, respectively, P<0.001. Ceftriaxone-Metronidazole was used in 75.9% of patients Group 2. When adjusting for other covariates, an SSI-decrease was associated only with Ceftriaxone-Metronidazole (OR 0.34, P<0.001). CONCLUSIONS: Ongoing process improvement has resulted in decreased SSIs with Ceftriaxone-Metronidazole prophylaxis. The benefit of Ceftriaxone-Metronidazole is independent of the biliary microbiome. Improving prophylaxis for those with suspected penicillin allergy is warranted.

Development of a reproducible porcine model of infected burn wounds.

Severe burns are traumatic and physically debilitating injuries with a high rate of mortality. Bacterial infections often complicate burn injuries, which presents unique challenges for wound management and improved patient outcomes. Currently, pigs are used as the gold standard of pre-clinical models to study infected skin wounds due to the similarity between porcine and human skin in terms of structure and immunological response. However, utilizing this large animal model for wound infection studies can be technically challenging and create issues with data reproducibility. We present a detailed protocol for a porcine model of infected burn wounds based on our experience in creating and evaluating full thickness burn wounds infected with Staphylococcus aureus on six pigs. Wound healing kinetics and bacterial clearance were measured over a period of 27 d in this model. Enumerated are steps to achieve standardized wound creation, bacterial inoculation, and dressing techniques. Systematic evaluation of wound healing and bacterial colonization of the wound bed is also described. Finally, advice on animal housing considerations, efficient bacterial plating procedures, and overcoming common technical challenges is provided. This protocol aims to provide investigators with a step-by-step guide to execute a technically challenging porcine wound infection model in a reproducible manner. Accordingly, this would allow for the design and evaluation of more effective burn infection therapies leading to better strategies for patient care.

Clinical significance of donor lung weight at procurement and during ex vivo lung perfusion.

BACKGROUND: Elevated donor lung weight may adversely affect donor lung transplant suitability and post-transplant outcomes. The objective of this study is to investigate the impact of lung weight after procurement and ex vivo lung perfusion (EVLP) on transplant suitability, post-transplant graft dysfunction, and clinical outcomes and define the donor lung weight range most relevant to clinical outcomes. METHODS: From February 2016 to August 2020, 365 human lung donors to a single transplant center were retrospectively reviewed. 239 were transplanted without EVLP, 74 treated with EVLP (50 went on to transplant), and 52 declined for transplant without EVLP consideration. Donor lung weights were measured immediately after procurement and, when performed, after EVLP. Lung weights were adjusted by donor height and divided into 4 quartiles. RESULTS: Donor lungs in the highest weight quartile at donor hospital had a significantly lower transplant suitability rate after EVLP, higher rates of primary graft dysfunction grade 3 at 72 hours, and longer intensive care unit/hospital stay. For lungs treated with lung perfusion, the highest lung weight quartile at the end of lung perfusion was associated with a significantly lower transplant suitability rate, higher incidence of primary graft dysfunction grade 3 at 72 hours, and longer intensive care unit/hospital stay, compared to the other categories. CONCLUSIONS: Donor lung weight stratified by quartile categories can assist decision-making regarding need for EVLP at the donor hospital as well as during EVLP evaluation. Caution should be used when considering donor lungs in the highest weight quartile for transplantation.

Ex Vivo Normothermic Perfusion of Human Upper Limbs.

BACKGROUND: Ischemia-reperfusion injury remains a primary concern in upper extremity transplantation. Ex vivo normothermic perfusion (EVNP) enables near-physiological organ preservation, avoiding the deleterious effects of hypoxia and cooling. We investigated the effectiveness of human limb EVNP compared with static cold storage (SCS). METHODS: Twenty human upper extremities were procured. Ten were perfused at 38 °C with an oxygenated red blood cell-based solution, and contralateral limbs served as SCS control (4 °C). EVNP was terminated with systolic arterial pressure ≥115 mm Hg, compartment fullness, or a 20% decline in oxygen saturation. Weight, contractility, compartment pressure, tissue oxygen saturation, and uptake rates were assessed. Perfusate fluid dynamics, gases, electrolytes, and metabolites were measured. Myocyte injury scores and liquid chromatography-mass spectrometry analysis were performed. RESULTS: EVNP duration was 41.6 ± 9.4 h. Vascular resistance averaged 173.0 ± 29.4 mm Hg × min/L. Weight change and compartment pressures were 0.4 ± 12.2% ( P = 0.21) and 21.7 ± 15.58 mm Hg ( P = 0.003), respectively. Arterial and venous carbon dioxide partial pressure, oxygen saturation, and pH were 509.5 ± 91.4 mm Hg, 15.7 ± 30.2 mm Hg, 87.4 ± 11.4%, and 7.3 ± 0.2, respectively. Oxygen uptake rates averaged 5.7 ± 2.8 mL/min/g. Lactate reached 20 mmol/L after 15 (interquartile range = 6) h. Limb contractility was preserved for 30.5 (interquartile range = 15.8) h ( P < 0.001) and negatively correlated with perfusate potassium (ρ = -0.7, P < 0.001). Endpoint myocyte injury scores were 28.9 ± 11.5% (EVNP) and 90.2 ± 11.8% (SCS) ( P < 0.001). A significant increase in taurine ( P = 0.002) and decrease in tryptophan ( P = 0.002) were detected. Infrared thermography and indocyanine green angiography confirmed the presence of peripheral perfusion. CONCLUSIONS: EVNP can overcome the limitations of cold preservation by extending preservation times, enabling limb quality assessment, and allowing limb reconditioning before transplantation.

Lessons learned and keys to success: Provider experiences during the implementation of virtual oncology tumor boards in the era of COVID-19.

BACKGROUND AND OBJECTIVES: The COVID-19 pandemic required rapid adaptation of multidisciplinary tumor board conferences to a virtual setting; however, there are little data describing the benefits and challenges of using such a platform. METHODS: An anonymous quality improvement survey was sent to participants of tumor board meetings at a large academic institution. Participants answered questions pertaining to the relative strengths and weaknesses of in-person and virtual settings. RESULTS: A total of 335 responses (23.3% response rate) were recorded, and 253 met inclusion criteria. Respondents represented 25 different tumor board meetings, with colorectal, breast, and liver (18.6%, 17.0%, and 13.0%, respectively) being the most commonly attended. Virtual tumor boards were equivalent to in-person across 9 of 10 domains queried, while a virtual format was preferred for participation in off-site tumor boards. The lack of networking opportunities was ranked by physicians to be a significant challenge of the virtual format. Consistent leadership and organization, engaged participation of all attendees, and upgrading technology infrastructure were considered critical for success of virtual meetings. CONCLUSIONS: The implementation of virtual tumor board meetings has been associated with numerous challenges. However, improving several key aspects can improve participant satisfaction and ensure excellent patient care.

Correlation between physical status measures and frailty score in patients undergoing pancreatic resection.

BACKGROUND: This study aimed to assess the correlation between validated measures of physical status in a prehabilitation regimen with an established frailty score and analyze changes in these measures after completion of a directed prehabilitation program among patients undergoing elective pancreatic resection. METHODS: Adult patients undergoing pancreatic resection from 2019-2021 were enrolled in a pilot prehabilitation program. Three validated measures of physical status were used: the 6-minute walk test, grip strength, and chair-stand test. The prehabilitation program comprised 7,500 steps, 30 grip strength exercises, and 100 chair-stand exercises daily. Patients' frailty score was calculated using the Modified Johns Hopkins Frailty score. Changes in physical status measures after prehabilitation and postoperative outcomes were compared. RESULTS: Thirty-two patients with a median age of 69.0 years (interquartile range = 59.5-76.3 years) were included. Patients' median duration of participation was 21.5 days (interquartile range = 16-29 days). There was a negative correlation between increasing frailty score and baseline the 6-minute walk test (R2 = 0.17) and chair-stand test (R2 = 0.18). Patients' mean the 6-minute walk test decreased at the end of the prehabilitation program, while grip strength and chair-stand test were unchanged. When stratified by low or intermediate and high frailty scores, the differences in the 6-minute walk test and chair-stand test were unchanged. Hospital duration of stay, complications, and 90-day readmission rates were not different between frailty groups (P > .05). CONCLUSION: Correlation of physical status measures with frailty score suggests only one of these measures is sufficient to estimate patients' preoperative physical status. A longer, more comprehensive prehabilitation program or an expedited operation are likely the best strategies to improve patient outcomes.

Ex vivo normothermic preservation of amputated limbs with a hemoglobin-based oxygen carrier perfusate.

BACKGROUND: Ex vivo normothermic limb perfusion (EVNLP) preserves amputated limbs under near-physiologic conditions. Perfusates containing red blood cells (RBCs) have shown to improve outcomes during ex vivo normothermic organ perfusion, when compared with acellular perfusates. To avoid limitations associated with the use of blood-based products, we evaluated the feasibility of EVNLP using a polymerized hemoglobin-based oxygen carrier-201 (HBOC-201). METHODS: Twenty-four porcine forelimbs were procured from Yorkshire pigs. Six forelimbs underwent EVNLP with an HBOC-201-based perfusate, six with an RBC-based perfusate, and 12 served as static cold storage (SCS) controls. Ex vivo normothermic limb perfusion was terminated in the presence of systolic arterial pressure of 115 mm Hg or greater, fullness of compartments, or drop of tissue oxygen saturation by 20%. Limb contractility, weight change, compartment pressure, tissue oxygen saturation, oxygen uptake rates (OURs) were assessed. Perfusate fluid-dynamics, gases, electrolytes, metabolites, methemoglobin, creatine kinase, and myoglobin concentration were measured. Uniformity of skin perfusion was assessed with indocyanine green angiography and infrared thermography. RESULTS: Warm ischemia time before EVNLP was 35.50 ± 8.62 minutes (HBOC-201), 30.17 ± 8.03 minutes (RBC) and 37.82 ± 10.45 (SCS) (p = 0.09). Ex vivo normothermic limb perfusion duration was 22.5 ± 1.7 hours (HBOC-201) and 28.2 ± 7.3 hours (RBC) (p = 0.04). Vascular flow (325 ± 25 mL·min-1 vs. 444.7 ± 50.6 mL·min-1; p = 0.39), OUR (2.0 ± 1.45 mL O2·min-1·g-1 vs. 1.3 ± 0.92 mL O2·min-1·g-1 of tissue; p = 0.80), lactate (14.66 ± 4.26 mmol·L-1 vs. 13.11 ± 6.68 mmol·L-1; p = 0.32), perfusate pH (7.53 ± 0.25 HBOC-201; 7.50 ± 0.23 RBC; p = 0.82), flexor (28.3 ± 22.0 vs. 27.5 ± 10.6; p = 0.99), and extensor (31.5 ± 22.9 vs. 28.8 ± 14.5; p = 0.82) compartment pressures, and weight changes (23.1 ± 3.0% vs. 13.2 ± 22.7; p = 0.07) were not significantly different between HBOC-201 and RBC groups, respectively. In HBOC-201 perfused limbs, methemoglobin levels increased, reaching 47.8 ± 12.1% at endpoint. Methemoglobin saturation did not affect OUR (ρ = -0.15, r2 = 0.022; p = 0.45). A significantly greater number of necrotic myocytes was found in the SCS group at endpoint (SCS, 127 ± 17 cells; HBOC-201, 72 ± 30 cells; RBC-based, 56 ± 40 cells; vs. p = 0.003). CONCLUSION: HBOC-201- and RBC-based perfusates similarly support isolated limb physiology, metabolism, and function.

Metabolic Profiling of Skeletal Muscle During Ex-Vivo Normothermic Limb Perfusion.

INTRODUCTION: Ex vivo normothermic limb perfusion (EVNLP) provides several advantages for the preservation of limbs following amputation: the ability to maintain oxygenation and temperature of the limb close to physiological values, a perfusion solution providing all necessary nutrients at optimal concentrations, and the ability to maintain physiological pH and electrolytes. However, EVNLP cannot preserve the organ viability infinitely. We identified evidence of mitochondrial injury (swelling, elongation, and membrane disruption) after 24 hours of EVNLP of human upper extremities. The goal of this study was to identify metabolic derangements in the skeletal muscle during EVNLP. MATERIALS AND METHODS: Fourteen human upper extremities were procured from organ donors after family consent. Seven limbs underwent EVNLP for an average of 41.6 ± 9.4 hours, and seven contralateral limbs were preserved at 4°C for the same amount of time. Muscle biopsies were performed at 24 hours of perfusion, both from the EVNLP and control limbs. Perturbations in the metabolic profiles of the muscle during EVNLP were determined via untargeted liquid chromatography-mass spectrometry (MS) operated in positive and negative electrospray ionization modes, over a mass range of 50 to 750 Da. The data were deconvoluted using the XCMS software and further statistically analyzed using the in-house statistical package, MetaboLyzer. Putative identification of metabolites using exact mass within ±7 ppm mass error and MS/MS spectral matching to the mzCloud spectral library were performed via Compound Discoverer v.2.1 (Thermo Scientific, Fremont, CA, USA). We further validated the identity of candidate metabolites by matching the fragmentation pattern of these metabolites to those of their reference pure chemicals. A nonparametric Mann-Whitney U-test was used to compare EVNLP and control group spectral features. Differences were considered significantly different when P-value < 0.05. RESULTS: We detected over 13,000 spectral features of which 58 met the significance criteria with biologically relevant putative identifications. Furthermore we were able to confirm the identities of the ions taurine (P-value: 0.002) and tryptophan (P-value: 0.002), which were among the most significantly perturbed ions at 24 hours between the experimental and control groups. Metabolites belonging to the following pathways were the most perturbed at 24 hours: neuroactive ligand-receptor interaction (P-values: 0.031 and 0.036) and amino acid metabolism, including tyrosine and tryptophan metabolism (P-values: 0.015, 0.002, and 0.017). Taurine abundance decreased and tryptophan abundance increased at 24 hours. Other metabolites also identified at 24 hours included phenylalanine, xanthosine, and citric acid (P-values: 0.002, 0.002, and 0.0152). DISCUSSION: This study showed presence of active metabolism during EVNLP and metabolic derangement toward the end of perfusion, which correlated with detection of altered mitochondrial structure, swelling, and elongation.

Wide posterior gluteal-thigh propeller flap for reconstruction of perineal defects.

INTRODUCTION: With increasing popularity of minimally invasive approaches to abdominoperineal resection (APR), thigh-based flaps are becoming the preferred option for reconstruction. The gluteal-thigh flap provides sufficient bulk, albeit with a high complication rate. We reevaluated the vascularization and design of the gluteal-thigh flap. The purpose of this study is to highlight the importance of the vascularization of the posterior thigh skin by the descending branch of the inferior gluteal artery (IGA) and the profunda femoris artery (PFA) perforators to design a more reliable and versatile gluteal thigh flap. This flap is indicated in selected cases in which use of vertical rectus abdominis musculocutaneous flap is not feasible. METHODS: Eleven fresh cadavers were used. The course, distribution, and diameter of IGA and PFA perforators were recorded. A wide posterior gluteal-thigh propeller flap (WPGTPF) was designed including the distance between the ischiatic tuberosity and greater trochanter; and extending it to within 8 cm of the popliteal fossa to improve flap reliability. Ten patients (mean age of 58.7 ± 10.6 years) underwent APR due to anal cancer (2) and rectal cancer (8); the approach was open in 3, laparoscopic in 6, and robotic in 1. All 10 patients received unilateral flap with a width of 12 ± 3.3 cm and surface of 405.5 ± 175.9 cm2 . RESULTS: The descending branch of the IGA was dominant in 72.7% of the specimens. In 22.7% of the specimens, the pedicle of the flap derived from the first or second PFA perforators. In one case, there was a double vascularization. Descending branch of the IGA was mapped at 46 ± 7.96 mm on the X-axis (horizontal line from the ischial tuberosity [IT] to the greater trochanter) and -12.1 ± 17.9 mm on the Y-axis (vertical line from the IT to the Medial Femoral condyle). Its average caliber measured 2.18 ± 0.3 mm. The first and second PFA perforators were located at 101.6 ± 17.9 mm and 104.5 ± 15.5 mm on the X-axis; 35.9 ± 27.1 mm and 89.2 ± 37.6 mm on the Y-axis. Their average diameters were 1.84 ± 0.41 mm and 1.48 ± 0.3 mm. In two cases, the flap was based on the first PFA perforator, the rest were on the descending branch of the IGA. Neither complete nor partial flap necrosis was observed. One patient developed coccyx osteomyelitis treated and resolved with bone debridement and one patient developed a seroma of the lateral thigh that was treated conservatively. Three patients underwent a debulking procedure by a combination of liposuction and resection to improve the gluteal symmetry. All ten flaps survived completely. CONCLUSIONS: Harvest of a wide flap that includes the PFA perforators and implementation of the propeller design increase the survival and versatility of the flap.

External Approach to Buccal Fat Excision in Facelift: Anatomy and Technique.

BACKGROUND: Masculinization of the face is a common finding in facelift patients. It is attributed to deflation and decent of the midface-jowls coupled with skin laxity. Fullness is evident lateral to the jowl in a small percentage due to prominent buccal fat pad (BFP). OBJECTIVES: The authors sought to examine the anatomy of the BFP, triangulate the prominent BFP with surgical landmarks, and describe an external approach to excise the BFP during facelift surgery. METHODS: Eighteen cadaveric dissections were performed. Facelift flap was elevated and the prominent buccal extension of the BFP protruding through the superficial-musculo-aponeurotic-system was identified. Measurements were taken from the BFP to surgical landmarks: zygomatic arch, tragus, and gonial angle. The locations of the facial nerve, parotid duct, and vascular pedicle relative to the BFP were calculated. RESULTS: BFP was 4.1 cm inferior to the zygomatic arch, 7.5 cm anterior the tragus, and 4.5 cm medial the gonial angle. The middle facial artery supplied the BFP on the inferior-lateral quadrant in 61% and inferior-medial quadrant in 39% of specimens . In all specimens, the parotid duct traversed the BFP superiorly, and the buccal branches of the facial nerve traversed the capsule superficially. CONCLUSIONS: The buccal extension of the BFP can pseudoherniate in the aging face. Excision may improve lower facial contour. Measurements from facial landmarks may help surgeons identify the buccal extension of the BFP intraoperatively. The surgeon must be careful of the vascular pedicle, parotid duct, and the facial nerve. The external approach safely excises buccal fat during facelift dissection while avoiding intraoral incisions and unnecessary contamination.

The Effect of Blood Transfusion in Lung Donors on Recipient Survival.

BACKGROUND: Blood transfusion can have detrimental effects on the pulmonary system, leading to lung injury and respiratory decompensation with subsequent increased morbidity and mortality in surgical and critically ill patients. How much of this effect is carried from a lung donor to transplant recipient is not fully understood, raising questions regarding transplant suitability of lungs from transfused donors. METHODS: United Network for Organ Sharing data were reviewed. Lung transplants from adult donors and known donor transfusion status were included; multiorgan transplants and retransplants were excluded. Recipient mortality was evaluated based on donor and recipient characteristics using a Kaplan-Meier survival estimate, Cox proportional hazards, and logistic regression models. We further assessed whether recipient mortality risk modified the donor transfusion effect. RESULTS: From March 1996 to June 2017, 20,294 transplants were identified. Outcome analysis based on transfusion status showed nonsignificant difference in 1-year mortality (P = .214). Ninety-day recipient mortality was significantly higher with transfusion of >10 units (U) vs 1-10 U or no transfusion (8.5%, 6.1%, and 6.0%, respectively, P = .005). Multivariable analysis showed increased 90-day mortality with transfusion of >10 U compared to no transfusion (odds ratio 1.62, P < .001), whereas 1-10 U showed no difference (odds ratio 1.07, P = .390). When stratified by recipient transplant risk, transfusion of >10 U was associated with increased mortality even with the lowest-risk recipients, while transfusion of 1-10 U showed no mortality increase even in the highest-risk recipients. CONCLUSIONS: Donor transfusion of >10 U of blood was associated with increased 90-day recipient mortality even in low-risk transplants. This risk should be considered when evaluating donor lungs.

Leukoreduction in ex vivo perfusion circuits: comparison of leukocyte depletion efficiency with leukocyte filters.

BACKGROUND: Leukodepletion of whole blood-based perfusates remains a challenge in experimental models of ex vivo perfusion. This study investigated the leukoreduction efficacy of the commonly used LeukoGuard LG Arterial and BC2 Cardioplegia filters. METHODS: Eleven liters of washed porcine blood was used to evaluate the filtration efficiency of LG (n = 6) and BC2 (n = 5) filters. Filter efficacy was tested by passing 1 L of washed blood through each filter. Complete blood count was performed to detect a reduction of white blood cells, red blood cells, and hemoglobin concentration. RESULTS: The BC2 Cardioplegia filter showed a significant reduction in white blood cell count (13.16 ± 4.2 × 103 cells/µL pre-filtration, 0.62 ± 0.61 cells/µL post-filtration, p = 0.005), red blood cell count (9.18 ± 0.16 × 106 cells/µL pre-filtration, 9.02 ± 0.16 × 106 cells/µL post-filtration, p = 0.012) and hemoglobin concentration (15.89 ± 0.66 g/dL pre-filtration, 15.67 ± 0.83 g/dL post-filtration, p = 0.017). Platelet reduction in the LG filter group was statistically significant (13.23 ± 13.98 × 103 cells/µL pre-filtration, 7.15 ± 3.31 × 103 cells/µL post-filtration, p = 0.029), but no difference was seen in the BC2 group. There was no significant difference in white blood cell count in the LG filter group (10.12 ± 3.0 × 103 cells/µL pre-filtration, 10.32 ± 2.44 × 103 cells/µL post-filtration, p = 0.861). CONCLUSION: Our results suggest that the LG filter should not be used in ex vivo perfusion circuits for the purpose of leukodepletion. The BC2 filter can be used in EVP circuits with flow rates of less than 350 mL/min. Alternatively, perfusate may be leukodepleted before perfusion.

Extended ex vivo normothermic perfusion for preservation of vascularized composite allografts.

Ischemia and reperfusion injury remains a significant limiting factor for the successful revascularization of amputated extremities. Ex vivo normothermic perfusion is a novel approach to prolong the viability of the amputated limbs by maintaining physiologic cellular metabolism. This study aimed to evaluate the outcomes of extended ex vivo normothermic limb perfusion (EVNLP) in preserving the viability of amputated limbs for over 24 hours. A total of 10 porcine forelimbs underwent EVNLP. Limbs were perfused using an oxygenated colloid solution at 38°C containing washed RBCs. Five forelimbs (Group A) were perfused for 12 hours and the following 5 (Group B) until the vascular resistance increased. Contralateral forelimbs in each group were preserved at 4°C as a cold storage control group. Limb viability was compared between the 2 groups through assessment of muscle contractility, compartment pressure, tissue oxygen saturation, indocyanine green (ICG) angiography and thermography. EVNLP was performed for 12 hours in group A and up to 44 hours (24-44 hours) in group B. The final weight increase (-1.28 ± 8.59% vs. 7.28 ± 15.05%, P = .548) and compartment pressure (16.50 ± 8.60 vs. 24.00 ± 9.10) (P = .151) were not significantly different between the two groups. Final myoglobin and CK mean values in group A and B were: 875.0 ± 325.8 ng/mL (A) versus 1133.8 ± 537.7 ng/mL (B) (P = .056) and 53 344.0 ± 16 603.0 U/L versus 64 333.3 ± 32 481.8 U/L (P = .286). Tissue oxygen saturation was stable until the end in both groups. Infra-red thermography and ICG-angiography detected variations of peripheral limb perfusion. Our results suggest that extended normothermic preservation of amputated limbs is feasible and that the outcomes of prolonged EVNLP (>24 hours) are not significantly different from short EVNLP (12 hours).

Ex-Vivo Normothermic Limb Perfusion With a Hemoglobin-Based Oxygen Carrier Perfusate.

INTRODUCTION: Ex-vivo normothermic limb perfusion (EVNLP) has been proven to preserve limb viability better than standard cold storage. Perfusates containing packed red blood cells (pRBC) improve outcomes when compared to acellular perfusates. Limitations of pRBC-based perfusion include limited availability, need for cross match, mechanical hemolysis, and activation of pro-inflammatory proteins. Hemoglobin-based oxygen carrier (HBOC)-201 (Hemopure) is a solution of polymerized bovine hemoglobin, characterized by low immunogenicity, no risk of hemolytic reaction, and enhanced convective and diffusive oxygen delivery. This is a preliminary study on the feasibility of EVNLP using HBOC-201 as an oxygen carrier. MATERIALS AND METHODS: Three porcine forelimb perfusions were performed using an established EVNLP model and an HBOC-201-based perfusate. The perfusion circuit included a roller pump, oxygenator, heat exchanger, and reservoir. Electrolytes, limb temperature, weight, compartment pressure, nerve conduction, and perfusion indicated by indocyanine green angiography and infra-red thermography were monitored. Histological evaluation was performed with hematoxylin and eosin and electron microscopy. RESULTS: Three limbs were perfused for 21.3 ± 2.1 hours. Muscle contractility was preserved for 10.6 ± 2.4 hours. Better preservation of the mitochondrial ultrastructure was evident at 12 hours in contrast to crystallization and destruction features in the cold-storage controls. CONCLUSIONS: An HBOC-201-EVNLP produced outcomes similar to RBC-EVNLP with preservation of muscle contractility and mitochondrial structure.