RAS Mutation Decreases Overall Survival After Optimal Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy of Colorectal Peritoneal Metastasis: A Modification Proposal of the Peritoneal Surface Disease Severity Score.

BACKGROUND: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are currently the most accepted treatment for peritoneal metastases from colorectal cancer. Restrictive selection criteria are essential to obtain the best survival benefits for this complex procedure. The most widespread score for patient selection, the peritoneal surface disease severity score (PSDSS), does not include current biological factors that are known to influence on prognosis. We investigated the impact of including RAS mutational status in the selection criteria for these patients. METHODS: We studied the risk factors for survival by multivariate analysis using a prospective database of consecutive patients with carcinomatosis from colorectal origin treated by CRS and HIPEC in our unit from 2009 to 2017. The risk factors obtained were validated in a multicentre, international cohort, including a total of 520 patients from 15 different reference units. RESULTS: A total of 77 patients were selected for local análisis. Only RAS mutational status (HR: 2.024; p = 0.045) and PSDSS stage (HR: 2.90; p = 0.009) were shown to be independent factors for overall survival. Early PSDSS stages I and II associated to RAS mutations impaired their overall survival with no significant differences with PSDSS stage III overall survival (p > 0.05). These results were supported by the international multicentre validation. CONCLUSIONS: By including RAS mutational status, we propose an updated RAS-PSDSS score that outperforms PSDSS alone providing a quick and feasible preoperative assessment of the expected overall survival for patients with carcinomatosis from colorectal origin undergone to CRS + HIPEC.

Validation in colorectal procedures of a useful novel approach for the use of C-reactive protein in postoperative infectious complications.

AIM: Our aim was to validate a novel use of C-reactive protein (CRP) measurement to identify postoperative infectious complications in patients undergoing colorectal surgery, and to compare the predictive value in this setting against white blood cell (WBC) count and neutrophil-to-lymphocyte ratio (NLR). METHOD: This was a retrospective study of CRP, NLR and WBC measurements in patients undergoing colorectal surgery. CRP, NLR and WBC were recorded on the second postoperative day and on the day of infectious complication (patients who developed infectious complications) or within 3 days prior to discharge (subjects with no complications). The test for detecting infectious complications consisted of comparing the value of the inflammatory marker on the day on which a complication was suspected against the value recorded on the second postoperative day. The test was considered positive if a given value was higher than the registered peak at postoperative day 2. Factors influencing the postoperative peak CRP were also studied. RESULTS: A total of 254 patients were retrospectively studied. Patients whose CRP value was higher than on the second postoperative day had a diagnostic accuracy for infectious complications of up to 94.4% and sensitivity, specificity, positive predictive value and negative predictive value of up to 97.4%, 93.4%, 85.7% and 99.1%, respectively. Poorer results were observed when WBC count and NLR were used rather than CRP measurement. Multiple linear regression analysis showed that surgical procedure and approach, as well as additional resections, were independent factors for 48 h peak CRP. CONCLUSION: C-reactive protein is a better parameter than WBC count and NLR for detecting infectious complications. Our proposed methodology presents good diagnostic accuracy and performance and could potentially be used for any surgical procedure.

Prediction models of donor arrest and graft utilization in liver transplantation from maastricht-3 donors after circulatory death.

Shortage of organs for transplantation has led to the renewed interest in donation after circulatory-determination of death (DCDD). We conducted a retrospective analysis (2001-2009) and a subsequent prospective validation (2010) of liver Maastricht-Category-3-DCDD and donation-after-brain-death (DBD) offers to our program. Accepted and declined offers were compared. Accepted DCDD offers were divided into donors who went on to cardiac arrest and those who did not. Donors who arrested were divided into those producing grafts that were transplanted or remained unused. Descriptive comparisons and regression analyses were performed to assess predictor models of donor cardiac arrest and graft utilization. Variables from the multivariate analysis were prospectively validated. Of 1579 DCDD offers, 621 were accepted, and of these, 400 experienced cardiac arrest after withdrawal of support. Of these, 173 livers were transplanted. In the DCDD group, donor age < 40 years, use of inotropes and absence of gag/cough reflexes were predictors of cardiac arrest. Donor age >50 years, BMI >30, warm ischemia time >25 minutes, ITU stay >7 days and ALT ≥ 4× normal rates were risk factors for not using the graft. These variables had excellent sensitivity and specificity for the prediction of cardiac arrest (AUROC = 0.835) and graft use (AUROC = 0.748) in the 2010 prospective validation. These models can feasibly predict cardiac arrest in potential DCDDs and graft usability, helping to avoid unnecessary recoveries and healthcare expenditure.

Laparoscopic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for limited peritoneal metastasis. The PSOGI international collaborative registry.

INTRODUCTION: A laparoscopic approach for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (L-CRS+HIPEC) in highly selected patients has been reported in small cohorts with a demonstrable reduction in length of stay and post-operative morbidity. This study aims to analyse individual patient data from these international centres collected through the Peritoneal Surface Oncology Group International (PSOGI) L-CRS+HIPEC registry. METHODS: An international registry was designed through a networking database (REDCAP®). All centres performing L-CRS+HIPEC were invited through PSOGI to submit data on their cases. Patient's characteristics, postoperative outcomes and survival were analysed. RESULTS: Ten international centres contributed a total of 143 L-CRS+HIPEC patients during the study period. The most frequent indication was low grade pseudomyxoma peritonei in 79/143 (55%). Other indications were benign multicyst mesothelioma in 21/143(14%) and peritoneal metastasis from colon carcinoma in 18/143 (12,5%) and ovarian carcinoma in 13/143 (9%). The median PCI was 3 (2-5). The median length of stay was 6 (5-10) days, with 30-day major morbidity rate of 8.3% and 30-day mortality rate of 0.7%. At a median follow-up of 37 (16-64) months 126/143 patients (88.2%) were free of disease. CONCLUSIONS: Analysis of these data demonstrates that L-CRS+HIPEC is a safe and feasible procedure in highly selected patients with limited peritoneal disease when performed at experienced centres. While short to midterm outcomes are encouraging in patients with less invasive histology, longer follow up is required before recommending it for patients with more aggressive cancers with peritoneal dissemination.

The anatomy, paleobiology, and evolutionary relationships of the largest extinct side-necked turtle.

Despite being among the largest turtles that ever lived, the biology and systematics of Stupendemys geographicus remain largely unknown because of scant, fragmentary finds. We describe exceptional specimens and new localities of S. geographicus from the Miocene of Venezuela and Colombia. We document the largest shell reported for any extant or extinct turtle, with a carapace length of 2.40 m and estimated mass of 1.145 kg, almost 100 times the size of its closest living relative, the Amazon river turtle Peltocephalus dumerilianus, and twice that of the largest extant turtle, the marine leatherback Dermochelys coriacea. The new specimens greatly increase knowledge of the biology and evolution of this iconic species. Our findings suggest the existence of a single giant turtle species across the northern Neotropics, but with two shell morphotypes, suggestive of sexual dimorphism. Bite marks and punctured bones indicate interactions with large caimans that also inhabited the northern Neotropics.

Planning Generational Change in a Liver Transplant Team.

Liver transplantation (LT) is a demanding and stressful practice. It requires full dedication and great personal sacrifice. It carries with it a long, difficult learning curve. We present the current situation with one LT team and carried out a critical analysis on the current problems in LT units with regard to access to leadership the future generational changes. An LT team has several similarities with a family-owned company. A generation change planning in liver transplantation may address 3 important aspects: the succession of the leader; establishment and reinforcement of the talent pool; and accessibility to the working group. An LT team is manned by highly qualified personnel. The ideal scenario is when the successor surgeon is accepted by every member in a joint agreement; all the surgeons on the team have the potential to be the next team leader; and the working group presents a high level of personal effort and a motivated attitude. There is an ongoing problem in LT units, however-the growing lack of interest from young surgeons to be part of a transplant team. There are many reasons for this, but it primarily involves the high level of dedication required. The formation of a good transplant team, with a pool of high-quality young surgeons and the realization of a proper generational change, could improve its operation and its results in the future.

Laparoscopic Living Donor Hepatectomy for Pediatric Liver Transplantation: the First 7 Cases in Spain.

Herein we report on laparoscopic donor hepatectomy (left lateral sectionectomy) for pediatric living donor liver transplantation by using a pure laparoscopic approach. Seven laparoscopic living donor procedures were performed during the period March 2016 to February 2017 at our institution. The average age of donors was 33.3 years. Preoperative liver function was normal in all donors. Four donors required 1 or more Pringle maneuver(s). The etiology was biliary atresia (n = 3), metabolic disorders (n = 2) (OTC deficiency), Alagille syndrome (n = 1), and neonatal ductopenia (n = 1). The graft was implanted orthotopically in 6 patients; we performed an auxilliary transplantation in a patient with an OTC deficiency. The time of donor surgery was 363 minutes. Dindo-Clavien complications among donors were type I (n = 1), type IIa (n = 1), and type IIb (n = 2). The mean hospital stay for the recipients was 14 days. The mean donor stay was 3.7 days. Perioperative donor and recipient mortality was 0%. Graft survival was 87.5% with 1 graft loss secondary to inadequate venous outflow. In conclusion, we can propose the laparoscopic approach in experienced centers as a "standard of practice" due to its minimal complication rate and short hospital stay.

Use of Peritoneovenous Shunt for the Management of Refractory Ascites.

BACKGROUND: Guidelines for the management of refractory ascites (RA) recommend transjugular intrahepatic portosystemic shunting (TIPS), diuretics, and paracentesis as the main strategies, discouraging use of surgical peritoneovenous shunts (PVSs). However, PVSs, including both Denver (DS) or saphenoperitoneal (SPS) modalities, may still have indications. Herein we report our experience with PVSs in the context of modern surgical and anesthetic management. METHODS: In our unit, PVSs are offered to patients with ascites refractory to diuretics in which TIPS are contraindicated. Heart function and spontaneous bacterial peritonitis must be assessed before surgical indication. RESULTS: Seven procedures were performed on 5 patients (6-DS, 1-SPS) in 2013. Their mean age was 61 (range, 54-68) years. In 3 patients, the indication was RA without options for liver transplant; 2 patients were on the waiting list for liver transplantation, which were performed to improve renal function and quality of life (QOL). The median hospital stay was 6.5 (range, 3-12) days. All patients were alive after 12 months. One patient died 2 years after the first DS and another later died due to liver insufficiency with patency of the DS. The ascites was well-controlled in 4 of 5 patients at up to 48 months of follow-up. Decreases in diuretics doses, proper weight maintenance, and a dramatic improvement in QOL (measured by a modified Ascites Symptom Inventory-7 [ASI-7] test) were observed after the procedures. CONCLUSION: PVSs are useful for the treatment of patients with RA who develop resistance to common therapies, leading to a major improvement in QOL. These surgical procedures should be included in the armamentarium of experienced liver surgeons.

Rescue of Discarded Grafts for Liver Transplantation by Ex Vivo Subnormothermic and Normothermic Oxygenated Machine Perfusion: First Experience in Spain.

BACKGROUND: Ex vivo machine perfusion (MP) has been reported as a possibly method to rescue discarded organs. The main aim of this study was to report an initial experience in Spain using MP for the rescue of severely marginal discarded liver grafts, and to, secondarily, define markers of viability to test the potential applicability of these devices for the real increase in the organ donor pool. METHODS: The study began in January 2016. Discarded grafts were included in a research protocol that consisted of standard retrieval followed by 10 hours of cold ischemia. Next, either normothermic (NMP) or controlled subnormothermic (subNMP) rewarming was chosen randomly. Continuous measurements of portal-arterial pressure and resistance were screened. Lactate, pH, and bicarbonate were measured every 30 minutes. The perfusion period was 6 hours, after which the graft was discarded and evaluated as potentially usable, but never implanted. Biopsies of the donor and at 2, 4, and 6 hours after ex vivo MP were obtained. RESULTS: A total of 4 grafts were included in the protocol. The first 2 grafts were perfused by NMP and grafts 3 and 4 by subNMP. The second and third grafts showed a clear trend toward optimal recovery and may have been used. Lactate dropped to levels below 2.5 mmol/L with stable arterial and portal pressure and resistance. Clear biliary output started during MP. Biopsies showed an improvement of liver architecture with reduced inflammation at the end of the perfusion. CONCLUSION: This preliminary experience has demonstrated the potential of MP devices for the rescue of severely marginal liver grafts. Lactate and biliary output were useful for viability testing of the grafts. The utility of NMP or subNMP protocols requires further research.

Model for end-stage liver disease can predict very early outcome after liver transplantation.

Postoperative Model for End-stage Liver Disease (MELD) values have never been assessed to predict very early (<1 week) death after liver transplantation (OLT). We retrospectively reviewed 275 consecutive OLTs performed in 252 recipients reported in a prospective database. We calculated the MELD score (pre-MELD) and consecutive postoperative MELD (post-MELD) scores computed daily during the first postoperative week and on days 15 and 30 after OLT. Post-MELD scores from nonsurviving recipients displayed on a scatterplot of immediate probability of death were adjusted to the best goodness-of-fit curve, and, finally, depicted graphically as a receiver operating characteristic (ROC) curve. Nonsurviving recipients showed higher post-MELD scores: day 1: 23.5 versus 16.6 (P = .05); day 3: 25.1 versus 12.5 (P = .000); day 5: 25.7 versus 11.8 (P = .000); and day 7: 22.1 versus 10.2 (P = .000). Overall comparisons were performed using a time-dependent general linear regression model, revealing higher post-MELD scores for nonsurviving recipients, irrespective of postoperative time (P = .002). The best goodness-of-fit curve was displayed when adjusting to a theoretical exponential regression curve calculated as follows: Probability of dying within the first week (%) = 3.36 x e(0.079 x (post-MELD)) (r = .89; P = .000). The area under the ROC curve was 0.783 (95% confidence interval, 0.630-0.935; P = .001). The model had a positive predictive value of 82.3%, a negative predictive value of 33.1%, and an accuracy of 79.2%. In conclusion, this study corroborated the suggestion that the MELD score may serve as a reliable tool to assess very early death after OLT.

Factors affecting survival and tumor recurrence in patients transplanted for hepatocellular carcinoma and coexistent hepatitis C virus.

A better understanding of tumor factors influencing patient and graft survival and recurrence of hepatocellular carcinoma (HCC) associated with hepatitis C virus (HCV) cirrhosis may be useful to maximize the benefits of liver transplantation (OLT). Sixty-three adults underwent OLT for end-stage liver disease secondary to HCV with concomitant HCC. The outcome measures were patient and graft survival, as well as recurrence-free survival, computed using a stepwise Cox proportional hazards regression analysis. Kaplan-Meier 1-, 3-, and 5-year patient survival rates were 82%, 80%, and 69%, respectively, they were better for incidentally discovered HCC compared with preoperatively diagnosed HCC (P = .04). The overall recurrence-free survival rates were 81%, 76%, and 61% at 1, 3, and 5 years, respectively. Univariate analysis showed that nonincidental HCC (P = .04), pTNM stage (P = .012) and vascular invasion (P = .003) correlated with recipient mortality. Vascular invasion (odds ratio [OR] = 2.12; P = .001) and pTNM (OR = 1.50; P = .008) were independent predictors of overall survival. A combination of tumor vascular invasion with advanced pTNM was associated with a dismal prognosis (log-rank = 21.89; P = .0001). Tumor grading (OR = 1.2; P = .04), pTNM (OR = 3.7; P = .001) and vascular invasion (OR = 1.6; P = .002) were independent predictors of recurrence. In conclusion, advanced pTNM and the presence of vascular invasion are strong predictors of poor survival and tumor recurrence.

Anti-TNF-alpha treatment and bile duct drainage restore cellular immunity and prevent tissue injury in experimental obstructive jaundice.

Several experimental studies of obstructive jaundice (OJ) have shown the presence of immunosuppressive state associated with the rise of tumor necrosis factor-alpha (TNF-alpha) concentration in plasma. The present study evaluates the impact of anti-TNF- alpha administration or bile duct drainage on the inflammatory response, liver injury and renal insufficiency in obstructed rats. OJ was induced by the ligation of bile duct in Wistar rats. The parameters were determined at 14 and 21 days after OJ. Two additional groups of animals were treated with anti-TNF-alpha antibodies or submitted to bile duct drainage at 14 days, and sacrificed 21 days after OJ. Cholestasis decreased glucose, and enhanced urea, creatinin, bilirubin and transaminases. Cholestasis increased the number of different inflammatory cells (T and B lymphocytes, and monocytes-macrophages) but reduced the expression of the corresponding cellular activation markers. This low responsiveness of the inflammatory cells was related to a decreased free radical production and phagocytic activity of cells. Anti-TNF-alpha and bile duct drainage reduced tissue injury, and prevented the reduction of the number and activity of T lymphocytes and phagocytic cells observed at the advanced stages of cholestasis. In conclusion, anti-TNF- alpha and bile duct drainage improved cell immunodeficiency, and reduced liver injury, cholestasis and renal insufficiency in experimental OJ.

Contribution of marginal donors to liver transplantation for hepatitis C virus infection.

The use of marginal liver donors can affect the outcomes of liver transplantation in patients with hepatitis C virus (HCV) infection. There are no firm conclusions about which donor criteria are important for allocation of high-risk grafts to recipients with HCV cirrhosis. We performed 120 consecutive liver transplantations for HCV infection between 1995 and 2005. Marginal donor criteria were considered to be: age >70 years, macrovesicular steatosis >30%, moderate-to-severe liver preservation injury, high inotropic drug dose (dopamine >15 microg/kg/min; epinephrine, norepinephrine, or dobutamine at any doses), peak serum sodium >155 mEq/L, any hypotensive episode <60 mm Hg and >1 hour, cold ischemia time >12 hours, ICU hospitalization >4 days, bilirubin >2 mg/dL, AST and/or ALT >200 UI/dL. Graft survival with donors showing these marginal criteria was compared with optimal donors using Kaplan-Meier analysis and the log-rank test. Independent predictors of survival were computed with the Cox proportional hazards model. Fifty-six grafts (46%) were lost during follow-up irrespective of the Model for End-Stage Liver Disease (MELD) scores of the recipients in each category. Upon univariate analysis, grafts with moderate-to-severe steatosis (P = .012), those with severe liver preservation injury (P = .007) and prolonged cold ischemia time (P = .0001) showed a dismal prognosis at 1, 3, and 5 years. Upon multivariate analysis, fat content (P = .0076; OR = 4.2) and cold ischemia time >12 hours (P = .034; OR = 7.001) were independent predictors of graft survival. Among HCV recipients, marginal liver donors worked similar to those from "good" donors, except for those with fatty livers >30%, especially when combined with a prolonged cold ischemia time.

Adjuvant chemotherapy for prevention of recurrence of invasive hepatocellular carcinoma after orthotopic liver transplantation.

UNLABELLED: Orthotopic liver transplantation (OLT) is the best treatment for nonresectable hepatocellular carcinoma (HCC), but tumor recurrence reduces long-term and medium-term survival. The effectiveness of adjuvant chemotherapy to prevent tumor recurrence has not been fully established. METHODS: Three hundred eighty-seven consecutive patients, including 43 with HCC superimposed on liver cirrhosis, underwent OLT. Twelve patients with one or more prognostic criteria for HCC recurrence were entered into a prospective prophylaxis protocol with monthly cycles of cisplatin (60 mg/m(2)) and adriamycin (30 mg/m(2)), beginning the fourth week post-OLT for a maximum of seven sessions. RESULTS: The 5-year survival of the non-HCC patients was 65.7% and that of the HCC patients was 60.46% (P = NS). Chemotherapy was reasonably well tolerated, but the 9 patients with hepatitis C- or B-associated cirrhosis showed viral and histological recurrence of the primary disease. A high proportion of patients (7 of 12) developed tumor recurrence during the first year after OLT. Six of these patients died, all but one due to HCC relapse. Five patients remain healthy and tumor free at 58 to 130 months. Post-OLT adjuvant chemotherapy does not avoid tumor recurrence and its fatal consequences but may contribute to prolonged tumor-free survival among a significant proportion of patients with high-risk HCC. However, the uncertain implications on viral recurrence and the lack of control groups do not allow post-OLT chemotherapy to be recommended outside controlled clinical trials, which are clearly warranted.

Optimizing the management of patients with BCLC stage-B hepatocellular carcinoma: Modern surgical resection as a feasible alternative to transarterial chemoemolization.

OBJECTIVE: To analyse the impact of liver resection (LR) in patients with Hepatocellular Carcinoma (HCC) within the Barcelona-Clinic-Liver-Cancer (BCLC)-B stage. METHODS: Analysis of patients with BCLC-B HCC treated with LR or transarterial chemoembolization (TACE) between 2007 and 2012 in our hospital. Survival/recurrence analyses were performed by log-rank tests and Cox multivariate models. Further analyses were specifically obtained for the HCC subclassification (B1-2-3-4) proposed recently. RESULTS: Eighty patients were treated (44-TACE/36-LR). Number of nodules was [1.8(1.1)], being multinodular in 50% of cases. Although resected patients had a higher hospital stay than those who underwent TACE (14 ± 13 vs 7 ± 6; P = 0.004), the rate and severity of complications was lower measured by Dindo-Clavien scale (P < 0.05). Overall survival was 40% with a median follow-up of 29.5 months (0.07-96.9). Five-years survival rates were 62.9%, 28.1% and 15.4%, respectively (P = 0.004) for B1, B2 and B3-4 stages. Cox model showed that only total bilirubin [OR = 2.055(1.23-3.44)] and BCLC subclassification B3-4 [OR = 2.439(1.04-5.7)] and B2 [OR = 2.79(1.35-5.77)] vs B1 were independent predictors of 5-years-survival. In B1 patients, surgical approach led a significant decrease in 5-years recurrence-rate (25% vs 60%; P = 0.018). In the surgical subgroup analysis, better results were observed if well/moderate differentiation combined with no microvascular-invasion (VI) in 5-years-survival (84.6%; P = 0.001) and -recurrence (23.1%; P = 0.041), respectively. These survival and recurrence trends were remarkable in B1 stages. CONCLUSIONS: Management of Intermediate BCLC-B HCC stage should be more complex and include updated criteria regarding B-stage subclassifications, VI and tumour differentiation. Modern surgical resection would offer improved survival benefit with acceptable safety in selected BCLC-B stage patients.

Monitoring of blood gases during prolonged experimental cardiopulmonary bypass and their relationship to brain pH, PO2, and PCO2.

Eight adult goats under went 5 hr of normothermic cardiopulmonary bypass (CPB) with pulsatile (n = 3) and nonpulsatile flow (n = 5). PaCO2 was maintained at 30-40 mmHg and blood flow rate at 50 ml/min/kg. Brain tissue pH, PO2, and PCO2, arterial and venous blood gases, and other systemic variables were monitored. No significant differences in brain electrochemistry between pulsatile and nonpulsatile perfusion were observed owing to the large variability of the results and the small number of experiments. The overall data for brain tissue pH, PO2, and PCO2 were analyzed and compared to the results of arterial and venous pH, PO2, and PCO2. Brain acidosis developed at the onset of bypass, and the values for brain tissue pH dissociated from those of blood pH, suggesting that hemodilution and the initial body response to CPB are involved in its development. Brain hypercapnia also developed during CPB, the values of brain tissue PCO2 dissociated from those of blood PCO2, and brain hypercapnia appears to be secondary to brain acidosis. Brain tissue PO2 closely followed the values of PvO2, suggesting that PvO2 can be an indicator of brain tissue PO2 during normothermic CPB and must be monitored during the procedure. Brain tissue acidosis is evidently related to neurologic dysfunction after CPB, and must be addressed. Replacement of the priming solution with whole blood or artificial blood, reduction of the priming volume, and application of vigorous pulsatile flow appear feasible interventions to mitigate brain tissue acidosis during CPB.

Achievement of physiologic pulsatile flow on cardiopulmonary bypass with a 24 French cannula.

In 1990, the NIH formally recognized the need for investigation of the problem of damaging the effects of cardiopulmonary bypass, issuing RFA HL-90-12-H, which emphasized production of neurologic defects in the very young and the elderly. The authors were at that time involved in comparison of pulsatile flow to steady flow cardiopulmonary bypass in large ungulates. The world literature recognizes five damaging effects of steady flow cardiopulmonary bypass that can be mitigated by pulsatile flow: metabolic acidosis, interstitial fluid accumulation, elevated systemic vascular resistance, arteriovenous shunting, and impaired brain oxygenation. To maximize the beneficial effect of pulsatile flow, however, it is necessary that its morphology be physiologic. It has been stated in the past that this goal may not be possible using standard size aortic cannulas. The purpose of this publication is to describe a method by which this feat has been achieved in 150 pound ungulates undergoing prolonged cardiopulmonary bypass.

Oxygen transport and consumption during experimental cardiopulmonary bypass using oxyfluor.

To evaluate a perfluorocarbon based oxygen carrier (Oxyfluor), a porcine model of cardiopulmonary bypass (CPB) was implemented. Swine (30 kg) were subjected to 2 h of normothermic CPB using Oxyfluor (OF group, n = 8) or Ringer's lactate (RL group, n = 13) as the prime. Mean arterial pressure (MAP) was kept at 50 mm Hg, flow rate at 80 ml x min(-1) x kg(-1), and PaCO2 at 35 mm Hg. Hemodynamic, hematologic, fluid balance, and blood gasimetry variables were measured. Total body oxygen delivery (DO2), consumption (VO2), and the fractional contribution to delivery (FCD) and to consumption (FCC) of the red blood cells (RBC), PFC, and plasma phases were calculated. Mixed venous PO2 (PvO2) was significantly higher at 30 min and 1 h on CPB in the OF group than in the RL group. FCCRBC was significantly lower at 30 min, 1 h, and 90 min on CPB in the OF group than in the RL group. PvjO2, Ca-vO2, Ca-vj O2, and VO2 were slightly higher in the OF group than in the RL group. Tissue fluid accumulation was not alleviated with Oxyfluor, and tissue and brain acidosis were significantly increased in the OF group. This study presented evidence that Oxyfluor improved tissue oxygenation and total body oxygen consumption during experimental CPB. In addition, Oxyfluor reduced FCCRBC, increasing oxygen transport reserve of the RBC phase, which can be useful to reduce hypoxic events during CPB. Further research should be conducted to optimize PFC-OCs for use in CPB and to reduce secondary effects.

Changes in brain pH, PO2, PCO2, cerebral blood flow, and blood gases induced by a hyperosmolar oxyreplete hemosubstitute during cardiopulmonary bypass.

Eleven goats (mean weight, 69 +/- 16 kg) underwent 5 hrs of normothermic nonpulsatile cardiopulmonary bypass (CPB) using as priming fluid either a Ringer's based crystalloid priming solution (CP, n = 5) of a hyperosmolar oxyreplete hemosubstitute (HS, n = 6). The HS contained 20% w/v perfluorocarbon (perfluorodecalin), its osmolarity was 800-900 mOsm/1, and the administered dose of perfluorocarbon was 30-50 ml/kg. Otherwise, the experimental procedure was identical for both groups. PaCO2 was maintained above 35 mmHg and blood flow rate at 65 ml/kg. Brain tissue pH, PO2, and PCO2, cerebral blood flow (CBF), arterial and venous blood gases, and other systemic variables were monitored. During CPB, PVO2 and brain tissue PO2 were increased significantly in the HS group. The CBF per kilogram of weight also was significantly higher in the HS group. Metabolic acidosis developed in both groups and, surprisingly, brain tissue pH and pHV were lower in the HS group. The mean values of PVCO2 and brain tissue PCO2 indicate that brain tissue hypercapnia also occurred in both groups. The HS provided long-term stability and compatibility with electrolytes, and did not cause major complications or allergic reactions during CPB. Perfluorocarbon based HSs improve tissue oxygenation, eliminate the risk of infection due to homologous transfusions, do not require blood type matching, have a shelf life longer than that of blood, and, therefore, they can be an important factor in diminishing the incidence of complications after CPB.