Could retrograde reperfusion combined with washout technique broaden the applicability of marginal grafts in liver transplantation? Intra-operative and short-term outcomes of a prospective cohort

INTRODUCTION

many revascularization techniques were designed to reduce the imbalance of ischemia-reperfusion injury. This study's objective is to evaluate retrograde reperfusion (RR) compared to sequential anterograde reperfusion (AR), with and without the washout technique (WO).

METHOD

this prospective cohort study collected data from 94 deceased donor orthotopic liver transplants and divided it into three groups: RR with WO (RR+WO), AP with WO (AR+WO), and AP without WO (AR). This study did not assign the reperfusion technique to the participants. The primary outcome considered the early graft dysfunction, and secondary outcomes included post-reperfusion syndrome (PRS), post-reperfusion lactate, surgery fluid balance, and vasoactive drug dose during the surgery.

RESULTS

87 patients were submitted to the final analysis-29 in the RR+WO group, 27 in the AR+WO group, and 31 in the AR group. Marginal grafts prevalence was not significantly different between the groups (34% vs. 22% vs. 23%; p=0.49) and early graft dysfunction occurred at the same rate (24% vs. 26% vs. 19%; p=0.72). RR+WO reduced serum post-reperfusion lactate (p=0.034) and the incidence of significant PRS (17% vs. 33% vs. 55%; p=0.051), but norepinephrine dosing >0.5mcg/kg/min were not different during the surgery (20,7% vs. 29,6% vs. 35,5%, p=0.45).

CONCLUSIONS

primary outcome was not significantly different between the groups; however, intraoperative hemodynamic management was safer using the RR+WO technique. We theorized that the RR+WO technique could reduce the incidence of PRS and benefit marginal graft survival following diseased donor orthotopic liver transplantation.

Understanding the Connection Between Common Stroke Comorbidities, Their Associated Inflammation, and the Course of the Cerebral Ischemia/Reperfusion Cascade

Despite the enormous progress in the understanding of the course of the ischemic stroke over the last few decades, a therapy that effectively protects neurovascular units (NVUs) and significantly improves neurological functions in stroke patients has still not been achieved. The reasons for this state are unclear, but it is obvious that the cerebral ischemia and reperfusion cascade is a highly complex phenomenon, which includes the intense neuroinflammatory processes, and comorbid stroke risk factors strongly worsen stroke outcomes and likely make a substantial contribution to the pathophysiology of the ischemia/reperfusion, enhancing difficulties in searching of successful treatment. Common concomitant stroke risk factors (arterial hypertension, diabetes mellitus and hyperlipidemia) strongly drive inflammatory processes during cerebral ischemia/reperfusion; because these factors are often present for a long time before a stroke, causing low-grade background inflammation in the brain, and already initially disrupting the proper functions of NVUs. Broad consideration of this situation in basic research may prove to be crucial for the success of future clinical trials of neuroprotection, vasculoprotection and immunomodulation in stroke. This review focuses on the mechanism by which coexisting common risk factors for stroke intertwine in cerebral ischemic/reperfusion cascade and the dysfunction and disintegration of NVUs through inflammatory processes, principally activation of pattern recognition receptors, alterations in the expression of adhesion molecules and the subsequent pathophysiological consequences.

Cerebral Edema in Patients With Large Hemispheric Infarct Undergoing Reperfusion Treatment: A HERMES Meta-Analysis

BACKGROUND AND PURPOSE

Whether reperfusion into infarcted tissue exacerbates cerebral edema has treatment implications in patients presenting with extensive irreversible injury. We investigated the effects of endovascular thrombectomy and reperfusion on cerebral edema in patients presenting with radiological evidence of large hemispheric infarction at baseline.

METHODS

In a systematic review and individual patient-level meta-analysis of 7 randomized controlled trials comparing thrombectomy versus medical therapy in anterior circulation ischemic stroke published between January 1, 2010, and May 31, 2017 (Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration), we analyzed the association between thrombectomy and reperfusion with maximal midline shift (MLS) on follow-up imaging as a measure of the space-occupying effect of cerebral edema in patients with large hemispheric infarction on pretreatment imaging, defined as diffusion-magnetic resonance imaging or computed tomography (CT)-perfusion ischemic core 80 to 300 mL or noncontrast CT-Alberta Stroke Program Early CT Score ≤5. Risk of bias was assessed using the Cochrane tool.

RESULTS

Among 1764 patients, 177 presented with large hemispheric infarction. Thrombectomy and reperfusion were associated with functional improvement (thrombectomy common odds ratio =2.30 [95% CI, 1.32-4.00]; reperfusion common odds ratio =4.73 [95% CI, 1.66-13.52]) but not MLS (thrombectomy β=-0.27 [95% CI, -1.52 to 0.98]; reperfusion β=-0.78 [95% CI, -3.07 to 1.50]) when adjusting for age, National Institutes of Health Stroke Score, glucose, and time-to-follow-up imaging. In an exploratory analysis of patients presenting with core volume >130 mL or CT-Alberta Stroke Program Early CT Score ≤3 (n=76), thrombectomy was associated with greater MLS after adjusting for age and National Institutes of Health Stroke Score (β=2.76 [95% CI, 0.33-5.20]) but not functional improvement (odds ratio, 1.71 [95% CI, 0.24-12.08]).

CONCLUSIONS

In patients presenting with large hemispheric infarction, thrombectomy and reperfusion were not associated with MLS, except in the subgroup with very large core volume (>130 mL) in whom thrombectomy was associated with increased MLS due to space-occupying ischemic edema. Mitigating cerebral edema-mediated secondary injury in patients with very large infarcts may further improve outcomes after reperfusion therapies.

Implications of liver donor age on ischemia reperfusion injury and clinical outcomes

The aging process causes detrimental changes in a variety of organ systems. These changes include: lesser ability to cope with stress, impaired repair mechanisms and decreased cellular functional reserve capacity. Not surprisingly, aging has been associated with increased susceptibility of donor heart and kidneys grafts to ischemia reperfusion injury (IRI). In the context of liver transplantation, however, the effect of donor age seems to be less influential in predisposing the graft to IRI. In fact, a widely comprehensive understanding of IRI in the aged liver has yet to be agreed upon in the literature. Nevertheless, there have been many reported implications of increased liver donor age with poor clinical outcomes besides IRI. These other poor outcomes include: earlier HCV recurrence, increased rates of acute rejection and greater resistance to tolerance induction. While these other correlations have been identified, it is important to re-emphasize the fact that a unified consensus in regard to liver donor age and IRI has not yet been reached among researchers in this field. Many researchers have even demonstrated that the extent of IRI in aged livers can be ameliorated by careful donor selection, strict allocation or novel therapeutic modalities to decrease IRI. Thus, the goals of this review paper are twofold: 1) To delineate and summarize the conflicting data in regard to liver donor age and IRI. 2) Suggest that careful donor selection, appropriate allocation and strategic effort to minimize IRI can reduce the frequency of a variety of poor outcomes with aged liver donations.

[Preventive measures of acute renal failure]

Many conditions can lead to acute renal failure. Some of them are intrinsic renal diseases whose natural history cannot be anticipated. On the other hand, others correspond to external aggressions driven by various hemodynamic or toxic events. To some extent, these can be partially prevented by relatively simple measures. The recognition of these situations which may benefit from a preventive strategy can significantly reduce morbidity or mortality associated with the incidence of acute renal failure.

Ischemia–reperfusion injury in patients with fatty liver and the clinical impact of steatotic liver on hepatic surgery

Hepatic steatosis is one of the most common hepatic disorders in developed countries. The epidemic of obesity in developed countries has increased with its attendant complications, including metabolic syndrome and non-alcoholic fatty liver disease. Steatotic livers are particularly vulnerable to ischemia/reperfusion injury, resulting in an increased risk of postoperative morbidity and mortality after liver surgery, including liver transplantation. There is growing understanding of the molecular and cellular mechanisms and therapeutic approaches for treating ischemia/reperfusion injury in patients with steatotic livers. This review discusses the mechanisms underlying the susceptibility of steatotic livers to ischemia/reperfusion injuries, such as mitochondrial dysfunction and signal transduction alterations, and summarizes the clinical impact of steatotic livers in the setting of hepatic resection and liver transplantation. This review also describes potential therapeutic approaches, such as ischemic and pharmacological preconditioning, to prevent ischemia/reperfusion injury in patients with steatotic livers. Other approaches, including machine perfusion, are also under clinical investigation; however, many pharmacological approaches developed through basic research are not yet suitable for clinical application.

[Anesthetic management of intra-aortic balloon occlusion (IABO) for seven cases of placenta accreta--a six year experience at our institute]

We studied retrospectively amount of bleeding, clamping time, and the presence or absence of ischemia-reperfusion injury in all seven cases of IABO performed for placenta accreta from 2007 to 2012 at our hospital. We also examined rSO2 change before and after clamping in four cases in which lower-limb rSO2 monitoring was performed with NIRS (near-infrared spectroscopy). There was no case suspected of ischemia-reperfusion injury during and after clamping with the amount of bleeding around 1,580-10,973 ml (mean 4,536 ml) and clamping time of 10-83 min (mean 44 min). No significant decrease was observed in lower-limb rSO2 with 73.5 ± 5.9% before clamping and 70.8 ± 5.6% (mean ± SD) after clamping.

Step-by-step vascular control for extracapsular resection of complex giant liver hemangioma involving the inferior vena cava

Massive hemorrhage remains an important clinical problem in extracapsular resection of giant liver hemangiomas (GLHs), especially for those involving the proximal hepatic veins and/or inferior vena cava. Between July 2004 and March 2012, 87 patients with a complex GLH scheduled for surgical treatment were included in this study. All patients were underwent vascular preparation (Step 1), advanced hepatic artery clamping (Step 2), and stepwise vascular occlusion (Step 3). Intraoperative blood loss, blood transfusion volume, degree of ischemia-reperfusion injury, and postoperative complications were recorded. No patients required urgent vascular preparation to manage intraoperative bleeding. In total, 87, 64, and 21 patients had portal triad (PT), infrahepatic inferior vena cava (IVC), and suprahepatic IVC preparation; and 17, 43, and 11 patients had PT, PT and suprahepatic IVC, and all three (PT, infra-, and suprahepatic IVC) occlusions. The PT, infrahepatic IVC, and SIVC occlusion times were 12.1 ± 3.7 minutes, 7.9 ± 2.4 minutes, and 3.2 ± 1.4 minutes, respectively. Mean blood loss was 291.9 ± 124.5 mL, and only four patients received blood transfusions. No patients had life-threatening complications or died (Clavien-Dindo Grade 4, 5). Compared with paralleled studies, this technique has an advantage to decrease the blood loss in less liver ischemia time. For complex GLH resections, the described step-by-step vascular control technique was efficacious and feasible for controlling intraoperative bleeding.

Phytochemicals: countering risk factors and pathological responses associated with ischaemia reperfusion injury

Plant derived non-nutritive molecules, known as phytochemicals, have been investigated for their ability to provide protection against inflammation. Emerging studies of several vasculopathies (e.g. atherosclerosis, hypertension) provide novel data to support these anti-inflammatory effects and offer evidence for involvement of host pathways. Fundamental mechanisms of action are common amongst these compounds, and furthermore, the administration of these phytochemicals activates host defence pathways innately present to protect cells from oxidative stress. This review will elucidate the real benefit of therapeutic intervention with these phytochemicals for vasculopathies, and associated ischaemia reperfusion injury in both the heart and brain.

Visceral ischaemia and organ dysfunction after hybrid repair of complex thoraco-abdominal aneurysms

BACKGROUND

The visceral hybrid repair of thoracoabdominal aneurysms (TAAAs) is a feasible and relatively safe alternative to traditional open repair in a cohort of patients at high surgical risk, averting the need for thoracotomy and supra-coeliac aortic cross clamping. The visceral ischaemia-reperfusion syndrome and organ dysfunction following visceral debranching is still unkown. This study investigates the relationship between visceral ischemia and multi system organ dysfunction.

PATIENTS AND METHODS

18 consecutive patients undergoing elective, urgent and emergent hybrid repair of TAAAs between February 2005 and October 2007 were prospectively analyzed. Preoperative organ dysfunction and intraoperative risk factors (operating time, extent of the aneurysm, number of visceral vessels by passed) were assessed and compared with postoperative organ dysfunction (pulmonary, hepatic, renal, pancreatic and haematological disorders). Blood sampling for neutrophil CD 11b quantification was performed at baseline, on postoperative days 1, 3, 7 and before discharge.

RESULTS

Perioperative Multi System Organ Dysfunction (MSOD) was diagnosed in 22.2% of patients (n = 4/18). Three of these patients died within 30 days (16.7%, n = 3/18). No relationship between preoperative organ dysfunction, blood loss, or operative time and postoperative organ dysfunction was observed. A significant correlation between the visceral retrograde revascularization and postoperative neutrophil expression in MSOD patients regardless of preoperative neutrophil baseline, TAAA extent and number of vessels by passed was present.

CONCLUSIONS

Upregulation of neutrophils may be responsible for the higher incidence of MSOD and it may be an important marker predicting a severe multiple organ failure following visceral debranching in hybrid procedures.

Does reperfusion injury still cause significant mortality after lung transplantation?

OBJECTIVES

Severe reperfusion injury after lung transplantation has mortality rates approaching 40%. The purpose of this investigation was to identify whether our improved 1-year survival after lung transplantation is related to a change in reperfusion injury.

METHODS

We reported in March 2000 that early institution of extracorporeal membrane oxygenation can improve lung transplantation survival. The records of consecutive lung transplant recipients from 1990 to March 2000 (early era, n = 136) were compared with those of recipients from March 2000 to August 2006 (current era, n = 155). Reperfusion injury was defined by an oxygenation index of greater than 7 (where oxygenation index = [Percentage inspired oxygen] x [Mean airway pressure]/[Partial pressure of oxygen]). Risk factors for reperfusion injury, treatment of reperfusion injury, and 30-day mortality were compared between eras by using chi(2), Fisher's, or Student's t tests where appropriate.

RESULTS

Although the incidence of reperfusion injury did not change between the eras, 30-day mortality after lung transplantation improved from 11.8% in the early era to 3.9% in the current era (P = .003). In patients without reperfusion injury, mortality was low in both eras. Patients with reperfusion injury had less severe reperfusion injury (P = .01) and less mortality in the current era (11.4% vs 38.2%, P = .01). Primary pulmonary hypertension was more common in the early era (10% [14/136] vs 3.2% [5/155], P = .02). Graft ischemic time increased from 223.3 +/- 78.5 to 286.32 +/- 88.3 minutes in the current era (P = .0001). The mortality of patients with reperfusion injury requiring extracorporeal membrane oxygenation improved in the current era (80.0% [8/10] vs 25.0% [3/12], P = .01).

CONCLUSION

Improved early survival after lung transplantation is due to less severe reperfusion injury, as well as improvements in survival with extracorporeal membrane oxygenation.

Circulating biochemical markers of brain damage in infants complicated by ischemia reperfusion injury

Hypoxia-ischemia constitutes a risk in infants by altering cerebral blood flow regulatory mechanisms and causing loss of cerebral vascular auto-regulation. Hypotension, cerebral ischemia, and reperfusion are the main events involved in vascular auto-regulation leading to cell death and tissue damage. Reperfusion could be critical since organ damage, particularly of the brain, may be amplified during this period. An exaggerated activation of vasoactive agents of calcium mediated effects could be responsible for reperfusion injury, which, in turns, leads to cerebral hemorrhage and damage. These dramatic phenomena represent a common repertoire in infants complicated by perinatal acute or chronic hypoxia or cardiovascular disorders treated by risky procedures such as open heart surgery and cardiopulmonary by-pass (CPB). To date, despite accurate perinatal and intra-operative monitoring, the post-insult period is crucial, since clinical symptoms and monitoring parameters may be of no avail and therapeutic window for pharmacological intervention (6-12 hours) may be limited, at a time when brain damage is already occurring. Therefore, the measurement of circulating biochemical markers of brain damage, such as vasoactive agents and nervous tissue peptides is eagerly awaited in clinical practice to detect high risk infants. The present review is aimed at investigating the role as circulating biochemical markers such as adrenomedullin, a vasoactive peptide; S100B, a calcium binding protein, activin A, a glycoprotein; neuronal specific enolase (NSE), a dimeric isoenzyme; glial fibrillary acid protein (GFAP), a astroglial protein, in the cascade of events leading to ischemia reperfusion injury in infants complicated by perinatal asphyxia or cardiovascular disorders requiring risky therapeutic strategies such as CPB and/or extracorporeal membrane oxygenation.

Laparoscopic Partial Nephrectomy with “On-Demand” Clamping Reduces Warm Ischemia Time

OBJECTIVES

To investigate the impact of "on-demand" clamping during laparoscopic partial nephrectomy on warm ischemia time.

METHODS

We retrospectively reviewed 39 consecutive patients with renal tumors who had undergone transperitoneal laparoscopic partial nephrectomy from April 2002 to May 2006. Median tumor size was 2.3 cm. In all cases, the hilum was dissected early and extracorporeal clamping performed. The pedicle was clamped only in case of excessive bleeding, and it was released immediately after the closure of the renal defect with knot-tying sutures over Surgicel bolsters.

RESULTS

Median operative time was 120 min. Renal clamping was required in 31 of 39 patients and in this subgroup the median warm ischemia time was 9 min. Median operative blood loss was 150 ml. Eight patients required blood transfusion and among these two were converted to open surgery. Positive surgical margin was observed in one case. Renal cell carcinoma was present in 22 (54.4%) specimens. No recurrence was observed after a median follow-up of 15 mo.

CONCLUSIONS

This novel technique using extracorporeal clamping significantly decreases warm ischemia time, avoiding clamping of the pedicle in selected cases. Our study underlines the feasibility of performing laparoscopic partial nephrectomy with extracorporeal hilar clamping, allowing the shortest ischemia time ever published.

Brain death activates donor organs and is associated with a worse I/R injury after liver transplantation

The majority of transplants are derived from donors who suffered from brain injury. There is evidence that brain death causes inflammatory changes in the donor. To define the impact of brain death, we evaluated the gene expression of cytokines in human brain dead and ideal living donors and compared these data to organ function following transplantation. Hepatic tissues from brain dead (n = 32) and living donors (n = 26) were collected at the time of donor laparotomy. Additional biopsies were performed before organ preservation, at the time of transplantation and one hour after reperfusion. Cytokines were assessed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and cytometric bead array. Additionally, immunohistological analysis of tissue specimens was performed. Inflammatory cytokines including IL-6, IL-10, TNF-alpha, TGF-beta and MIP-1alpha were significantly higher in brain dead donors immediately after laparotomy compared to living donors. Cellular infiltrates significantly increased in parallel to the soluble cytokines IL-6 and IL-10. Enhanced immune activation in brain dead donors was reflected by a deteriorated I/R injury proven by elevated alanin-amino-transferase (ALT), aspartat-amino-transferase (AST) and bilirubin levels, increased rates of acute rejection and primary nonfunction. Based on our clinical data, we demonstrate that brain death and the events that precede it are associated with a significant upregulation of inflammatory cytokines and lead to a worse ischemia/reperfusion injury after transplantation.

Effects of ischemic liver preconditioning on hepatic ischemia/reperfusion injury in the rat

To minimize bleeding during major liver resections or liver transplantation, surgical measures have been adopted that induce ischemia-reperfusion injury (I/R) which may significantly contribute to morbidity and mortality of partial liver resections. Several methods have sought to minimize I/R hepatic lesions. The present project assessed the protective role of ischemic preconditioning (IPC) in rat livers. The IPC was accomplished by clamping the hepatic pedicle for 5 minutes, followed by a 5-minute reperfusion (R) period before a 2-hour ischemia. Thereafter, reperfusions of 1, 3, and 24 hours were compared among IPC and control groups without IPC. Liver biopsy and blood samples were measured for mitochondrial respiratory control ratio (RCR), serum aspartate aminotransferase (AST), and alanine aminotransferase (ALT). IPC protected liver mitochondrial function. Serum aminotransferase levels were significantly lower among animals undergoing IPC compared with groups without IPC. Thus, we verified the effects of IPC for hepatocellular protection against I/R lesions.

Upper extremity palsy following cervical decompression surgery results from a transient spinal cord lesion

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To test the hypothesis that spinal cord lesions cause postoperative upper extremity palsy.

SUMMARY OF BACKGROUND DATA

Postoperative paresis, so-called C5 palsy, of the upper extremities is a common complication of cervical surgery. Although there are several hypotheses regarding the etiology of C5 palsy, convincing evidence with a sufficient study population, statistical analysis, and clear radiographic images illustrating the nerve root impediment has not been presented. We hypothesized that the palsy is caused by spinal cord damage following the surgical decompression performed for chronic compressive cervical disorders.

METHODS

The study population comprised 857 patients with chronic cervical cord compressive lesions who underwent decompression surgery. Anterior decompression and fusion was performed in 424 cases, laminoplasty in 345 cases, and laminectomy in 88 cases. Neurologic characteristics of patients with postoperative upper extremity palsy were investigated. Relationships between the palsy, and patient sex, age, diagnosis, procedure, area of decompression, and preoperative Japanese Orthopaedic Association score were evaluated with a risk factor analysis. Radiographic examinations were performed for all palsy cases.

RESULTS

Postoperative upper extremity palsy occurred in 49 cases (5.7%). The common features of the palsy cases were solely chronic compressive spinal cord disorders and decompression surgery to the cord. There was no difference in the incidence of palsy among the procedures. Cervical segments beyond C5 were often disturbed with frequent multiple segment involvement. There was a tendency for spontaneous improvement of the palsy. Age, decompression area (anterior procedure), and diagnosis (ossification of the posterior longitudinal ligament) are the highest risk factors of the palsy.

CONCLUSIONS

The results of the present study support our hypothesis that the etiology of the palsy is a transient disturbance of the spinal cord following a decompression procedure. It appears to be caused by reperfusion after decompression of a chronic compressive lesion of the cervical cord. We recommend that physicians inform patients and surgeons of the potential risk of a spinal cord deficit after cervical decompression surgery.

Preservation of the liver graft with Celsior solution

INTRODUCTION

We studied the evolution of the liver graft with preservation in Celsior (CS) compared with University of Wisconsin solution (UW).

MATERIAL AND METHODS

A randomized prospective clinical study in 80 liver transplants (OLTs) from May 2001 to October 2003, compared CS (group I; n = 40) and UW (group II; n = 40). The characteristics of the donors were homogeneous, with no significant differences in 15 variables. CS was perfused with 4 L through the aorta, 2 L through the portal vein, and 1 L, through the portal vein on the back table; and the UW, as 3 L, 2 L, and 1 L, respectively. All OLTs were performed using the piggyback technique.

RESULTS

Group I experienced reperfusion syndrome (n = 2; 5.9%), primary graft nonfunction (n = 0); vascular complications (n = 0); biliary anastomosis stenosis (n = 8; 22.9%), intensive care unit (ICU) days (n = 4.1 +/- 1), death within 30 days (n = 1; 3.1%). The patient and graft survivals at 1, 3, 6, 12, and 24 months were 93.7%, 93.7%, 90.2%, 85.7%, 85.7%, and 94.3%, 88.5%, 85.2%, 78%, 78%, respectively. For group II; the reperfusion syndrome occured in 6 patients (17.6%); primary graft nonfunction (n = 0); vascular complications (n = 0), biliary anastomosis stenosis (n = 3; 8.6%), ICU days (n = 4.9 +/- 2.4) and death within 30 days (n = 1; 3.1%); The patient and graft survival at 1, 3, 6, 12, and 24 months were 96.9%, 93.5%, 89.8%, 79.8%, 79.8% and 94.3%, 88.3%, 84.9%, 75.5%, 66.1%, respectively.

CONCLUSIONS

CS offers the similar safety to UW for preservation of liver grafts within these ischemia times.

Retrograde reperfusion via vena cava lowers the risk of initial nonfunction but increases the risk of ischemic-type biliary lesions in liver transplantation--a randomized clinical trial

Initial nonfunction (INF) and biliary complications such as ischemic-type biliary lesion (ITBL) remain two major complications in clinical orthotopic liver transplantation (OLT). The influence of ischemia and reperfusion injury (I/R) as a significant risk factor for both complications is widely unquestioned. A new reperfusion technique that reduces I/R injury should lead to a reduction in both INF and ITBL. One hundred and thirty two OLT patients were included in this study and randomized into two groups. Group A underwent standard reperfusion with anterograde simultaneous arterial and portal reperfusion and group B received retrograde reperfusion via the vena cava before sequential anterograde reperfusion of portal vein and hepatic artery. Serum transaminase level as a surrogate parameter for I/R injury and serum bilirubin level as a parameter for graft function were significantly reduced during the first week after OLT in group B. INF rate was 7.7% in group A and 0% in group B (P = 0.058). ITBL incidence was 4.55% in group A versus 12.3% in group B (P = 0.053). Retrograde reperfusion seemed to be beneficial for hepatocytes, but was detrimental for the biliary epithelium. The unexplained increased incidence of ITBL after retrograde reperfusion will be focus of further investigation.

Interstitial Lactic Acidosis in the Graft During Organ Harvest, Cold Storage, and Reperfusion of Human Liver Allografts Predicts Subsequent Ischemia Reperfusion Injury

BACKGROUND

The impact of the process of liver transplantation on glucose metabolism in the graft was studied using microdialysis.

METHODS

Microdialysis catheters were inserted into 15 human livers to monitor metabolic changes that took place during organ harvest, the process of backtable preparation of the graft, and following implantation in the recipient where it remained in situ for 48 hours. The cannula was perfused with isotonic solution and hourly samples of perfusate were collected and analyzed.

RESULTS

Six livers showed serum biochemical evidence of ischemia/reperfusion (IR) injury with 24 hours aspartate transaminase (AST) levels >2000 IU/L (Group A) whereas the remaining patients showed little evidence of IR injury (Group B). In Group A, lactate levels in the donor microdialysate rose to >6 mM (P < 0.05), were significantly higher during backtable preparation of the liver (>15 mM; P < 0.03), and took longer to normalize in the recipient following implantation (18 vs. 8 hours, P < 0.03) than lactate levels of the livers of patients in Group B who did not develop ischemia reperfusion injury. No significant differences were observed in glucose, pyruvate, or glycerol concentrations between the two groups.

CONCLUSIONS

Interstitial lactic acidosis in the donor allograft is associated with significant reperfusion injury on implantation.

Risk factors for reperfusion injury after lung transplantation

OBJECTIVE

To assess the influence of recipient's and donor's factors as well as surgical events on the occurrence of reperfusion injury after lung transplantation.

DESIGN AND SETTING

Retrospective study in the surgical intensive care unit (ICU) of a university hospital.

METHODS

We collected data on 60 lung transplantation donor/recipient pairs from June 1993 to May 2001, and compared the demographic, peri- and postoperative variables of patients who experienced reperfusion injury (35%) and those who did not.

RESULTS

The occurrence of high systolic pulmonary pressure immediately after transplantation and/or its persistence during the first 48 h after surgery was associated with reperfusion injury, independently of preoperative values. Reperfusion injury was associated with difficult hemostasis during transplantation (p=0.03). Patients with reperfusion injury were more likely to require the administration of catecholamine during the first 48 h after surgery (p=0.014). The extubation was delayed (p=0.03) and the relative odds of ICU mortality were significantly greater (OR 4.8, 95% CI: 1.06, 21.8) in patients with reperfusion injury. Our analysis confirmed that preexisting pulmonary hypertension increased the incidence of reperfusion injury (p<0.01).

CONCLUSIONS

Difficulties in perioperative hemostasis were associated with reperfusion injury. Occurrence of reperfusion injury was associated with postoperative systolic pulmonary hypertension, longer mechanical ventilation and higher mortality. Whether early recognition and treatment of pulmonary hypertension during transplantation can prevent the occurrence of reperfusion injury needs to be investigated.

Evolving Techniques and Perspectives in Lung Transplantation

Lung transplantation is currently a suitable option for patients with end-stage lung disease. Since the early 1980s the surgical technique and immunosuppressive protocols have been progressively modified to improve results and favor long-term survival. The original heart-lung transplantation under cardiopulmonary bypass is now rarely performed and single or bilateral lung transplantation is the procedure of choice. Bilateral transplantation is performed with two single lung transplants performed in sequence. Extracorporeal support is rarely employed and in most cases it is instituted through the femoral approach. Also, the surgical approach has been modified and the original clam shell incision has been replaced by two small anterior thoracotomies. The use of marginal donors has been increasingly proposed to enlarge the number of organs potentially available for transplantation. Immunosuppressive protocols have evolved to patient-specific regimens that can be quickly modified if required by the clinical status. Induction is now more aggressive and also rescue protocols for obliterative bronchiolitis can contribute to improved outcomes. Overall, lung transplantation is now performed with encouraging long-term results.

Graft ischemic time and outcome of lung transplantation: a multicenter analysis

RATIONALE

The effect of graft ischemic time on early graft function and long-term survival of patients who underwent lung transplantation remains controversial. Consequently, graft ischemic time has not been incorporated in the decision-making process at the time of graft acceptance.

OBJECTIVES

To investigate the relationship between graft ischemic time and (1) early graft function and (2) long-term survival after lung transplantation.

MEASUREMENTS AND MAIN RESULTS

The data from 752 patients who underwent single lung transplantation (n = 258), bilateral lung transplantation (n = 247), and heart-lung transplantation (n = 247) in seven French transplantation centers during a 12-year period were reviewed. Independent data quality control was done to ensure the quality of the collected variables. Mean graft ischemic time was 245.8 +/- 96.4 minutes (range 50-660). After adjustment on 11 potential confounders, graft ischemic time was associated with the recipient Pa(O2)/FI(O2) ratio recorded within the first 6 hours and with long-term survival in patients undergoing single or double lung transplantation but not in patients undergoing heart-lung transplantation. The relationship between graft ischemic time and survival appears to be of cubic form with a cutoff value of 330 minutes. These results were unaffected by the preservation fluid employed.

CONCLUSIONS

The results of this large cohort of patients suggest a close relationship between graft ischemic time and both early gas exchange and long-term survival after single and double lung transplantation. Such relationship was not found in patients undergoing heart-lung transplantation. The expected graft ischemic time should be incorporated in the decision-making process at the time of graft acceptance.

Reperfusion injury in renal transplantation: comparison of LD, HBD and NHBD renal transplants

Comparison of reperfusion injury in kidneys transplanted from LD, HBD or NHBD donors is presented in the paper. Central venous blood samples (taken during perioperative period) was assessed for free radicals, total antioxidant activity and various markers of tissue injury. There was demonstrable ischemia reperfusion injury occurring at the time of revascularization, which was particularly notable in kidneys transplanted from NHBD donors.

Recent trends in lung transplantation: the University of Minnesota experience

The number of transplants performed at our center continues to grow--partly as a result of the use of expanded donors and partly as a result of referrals from programs that have closed. We also anticipate having a more active living-donor lobar transplant program. The major acute problems that we encounter after transplantation are reperfusion injury and pneumonia. Improvements in perioperative mortality and morbidity will come with better lung preservation techniques and with an improved understanding of and an ability to modify the reperfusion process. BOS continues to be a major long-term problem for lung transplant patients. Although we do not understand the underlying pathogenesis of BOS, we are optimistic that BOS-free survival rates will increase with improvements in our ability to detect acute rejection as well as by avoidance of chronic injury to the lung from processes like GERD. Ongoing genetic analysis being conducted at our center will likely provide information about important biomarkers that define these processes.

Liberalization of donor criteria in lung transplantation

Donor shortage remains a major obstacle to widespread application of lung transplantation. In region 5, including California, Nevada, New Mexico, Utah, and Arizona, the United Network of Organ Sharing (UNOS) database median waiting time for lung transplant candidates in 2000-2001 exceeded 17 months. The purpose of this study was to determine the impact of liberalization of donor criteria on median waiting time and short-term outcome of lung transplantation. From September 1999 to October 2002, 42 patients underwent lung transplantation from nonstandard donors. The donors were classified as nonstandard due to (1) infiltrate on chest radiograph (n = 33), (2) PaO2 < 300 on FiO2 1.0 and PEEP 5 (n = 3), (3) PaO2 < 100 on FiO2 0.4 and PEEP 5 (n = 3), (4) purulent sputum on bronchoscopy (n = 22), and (5) smoking history greater than 50 pack-years (n = 1). Perioperative characteristics and short-term outcome of this group was analyzed. The median waiting time for this cohort was 114 days (range, 10-1267), as compared with the national UNOS database median waiting time of 24 months between 1996 and 2001. The incidence of ischemia reperfusion injury was 2.3 per cent. None of the recipients developed pneumonia. The median ventilator support time was 2 days (range, 1-95). The median ICU stay and hospital stay were 4 days (range, 2-103) and 14 days (range, 5-194), respectively. The 3-month survival was 97.6 per cent. Selective liberalization of donor lung criteria can decrease the waiting time and is associated with favorable short-term outcome. Utilization of nonstandard lungs can expand the donor pool.

Reperfusion injury after detorsion of unilateral ovarian torsion in rabbits

OBJECTIVE

To determine if reperfusion injury takes place in ovarian tissue following the detorsion of the torsioned ovary.

STUDY DESIGN

Fifty-four New Zealand mature nonpregnant female rabbits were divided into six groups. One group served to determine the basal values of thiobarbituric acid reacting substance (TBARS) and another group was sham. In the third and fourth groups, ovarian torsions and subsequent oophorectomy were performed in 1 and 3h, respectively. In the fifth and sixth groups, detorsions were carried out after unilateral ovarian torsion lasting 1 and 3h, respectively, then oophorectomies of the detorsioned ovaries were performed 2h after detorsion. The level of TBARS in ovarian tissues was determined in all subjects. Statistical analysis was performed using analysis of variance and Duncan's multiple range test. Differences were considered to be significant if P<0.05.

RESULTS

The levels of TBARS were not different in the basal and sham groups (P>0.05), while ovarian torsion caused significant increase in TBARS in the ovary (P<0.05), and detorsion caused a further significant increase in ovarian TBARS (P<0.05).

CONCLUSION

Reperfusion injury in ovarian tissue, following the detorsion after the torsion of the ovary lasting up to 3h was demonstrated biochemically in this study.

Hemorrhagic transformation is related to the duration of occlusion and treatment with tissue plasminogen activator in a nonembolic stroke model

The availability of reperfusion therapy for acute ischemic stroke patients has made the causes and significance of hemorrhagic transformation an area of intense interest and controversy. Ninety-two male Wistar rats underwent transient middle cerebral artery occlusion (MCAO) of between 1 and 6 h. Forty animals received 10 mg kg-1 of recombinant tissue plasminogen activator (rtPA), infused over 20 min, starting 5 min before reperfusion. At 18-24 h, the animals were sacrificed. The presence of hemorrhagic transformation (HT) on stained sections was recorded and total ischemic lesion area was quantified using image analysis software. Seventeen animals (11 with HT) were subjected to immunohistochemical analysis for detection of endothelial barrier antigen (EBA), quantified in three sections, in eight different fields per section. Chi-squared analysis and logistic regression were used to assess the contribution of rtPA and duration of occlusion to HT development. Nested, repeated measures analyses of variance were performed to assess the changes in EBA caused by ischemia and associated with HT. Fifty-nine animals developed HT that was significantly associated with occlusion duration (p < 0.0001) and ischemic lesion size (p = 0.0007). The presence of rtPA accelerated HT development. Statistically significant side-to-side differences in the presence of EBA were found in the striatum (core of the infarct) of animals with HT (p < 0.001) and without HT (p < 0.001), but only in animals with durations of occlusion of 2 h or more. Duration of occlusion is an important predictor of HT in transient MCAO in the rat and is closely associated with EBA expression.

Causes of postreperfusion syndrome in living or cadaveric donor liver transplantations

OBJECTIVE

The postreperfusion syndrome (PRS) occurrence was evaluated in patients undergoing liver transplantation in our institution to determine the relationship between PRS and associated variables.

METHODS

Of the 185 consecutive liver transplants, pediatric patients, patients with uncompleted data or retransplantations were excluded. The remaining 145 adult patients having 77 cadaveric and 68 living donor right lobe liver transplantations were studied. PRS was defined as a decrease in mean arterial pressure >30% below the baseline value. Logistic regression was used for statistical analyses. A P value <.05 was considered as significant.

RESULTS

Total rate of PRS occurrence was 48.9% (71 patients) for the 145 patients. Logistic regression analyses revealed a significant relationship between the PRS and four of the variables: shorter duration of the anhepatic period, higher mean calcium requirement, higher mean heart rate difference from anhepatic to reperfusion period and lower central venous pressure at the dissection period during operations (P <.05). We could not demonstrate any significant effect of the operation type-surgical technique and duration of operations, blood and fresh frozen plasma volume transfused, demographic variables of the recipients, donor liver factors, other haemodynamic and metabolic variables at specific time periods (P >.05).

CONCLUSIONS

In conclusion, it is important that PRS does not seem to occur in a predictable manner in this study except for the increased calcium requirements during the operations in PRS experienced patients. The clinical parameters as graft ischemia time, the type of the operation, demographic variables of the recipient, hemodynamic or metabolic variables and transfusion needs during the operations seemed to have no contribution to PRS occurrence.

Temporary arterial occlusion in the repair of ruptured intracranial aneurysms: an analysis of risk factors for stroke

OBJECT

This study was performed to further elucidate technical and patient-specific risk factors for perioperative stroke in patients undergoing temporary arterial occlusion during the surgical repair of their aneurysms.

METHODS

One hundred twelve consecutive patients in whom temporary arterial occlusion was performed during surgical repair of an aneurysm were retrospectively analyzed. Confounding factors (inadvertent permanent vessel occlusion and retraction injury) were identified in six cases (5%) and these were excluded from further analysis. The demographics for the remaining 106 patients were analyzed with respect to age, neurological status, aneurysm characteristics, intraoperative rupture, duration of temporary occlusion, and number of occlusive episodes; end points considered were outcome at 3-month follow up and symptomatic and radiological stroke.

CONCLUSIONS

Overall 17% of patients experienced symptomatic stroke and 26% had radiological evidence of stroke attributable to temporary arterial occlusion. A longer duration of clip placement, older patient age, a poor clinical grade (Hunt and Hess Grades IV-V), early surgery, and the use of single prolonged clip placement rather than repeated shorter episodes were associated with a higher risk of stroke based on univariate analysis. Intraoperative aneurysm rupture did not affect stroke risk. On multivariate analysis, only poorer clinical grade (p = 0.001) and increasing age (p = 0.04) were significantly associated with symptomatic stroke risk.

Bench to bedside: brain edema and cerebral resuscitation: the present and future

Sudden cardiac arrest (CA) claims approximately 1,200 lives daily in the United States. Cardiopulmonary resuscitation attempts have so far achieved suboptimal results, and even when restoration of spontaneous circulation (ROSC) is achieved, about 30% of survivors suffer permanent brain damage. This illustrates the need for an improved basic scientific understanding of the pathophysiology of global cerebral injury caused by whole-body ischemia/reperfusion (I/R) injury following CA. Brain edema has been recently documented in experimental CA followed by one hour of ROSC. Brain edema has also been documented in CA and stroke patients by computed tomography or magnetic resonance imaging scanning, and has been shown to predict a poor neurologic outcome. The mechanisms underlying brain edema formation elicited by CA are unclear. New scientific findings of the roles of blood-brain barrier (BBB) permeability, matrix metalloproteinases (MMPs) of a family of proteases, aquaporin 4 (AQP4) of a family of membrane water-channel proteins, and the N-methyl-D-aspartate (NMDA) receptors in the mechanisms underlying CA-elicited brain edema were reviewed. By defining the roles of BBB permeability, MMPs, AQP4, and NMDA receptors in CA-induced brain edema formation, effective new therapeutic strategies to extend cellular and tissue survival, and preserve neurologic function following CA may be feasible.

[Single-lung transplant and primary graft failure]

OBJECTIVE

To quantify primary graft failure (PGF) and its impact on perioperative and early mortality in single-lung transplant (SLT).

METHOD

We analyzed 35 SLT procedures performed using similar techniques. PGF was defined as a PaO2/FiO2 coefficient lower than 200 mmHg during the first 72 hours or ventilation assistance lasting longer than 5 days attributable to primary lung dysfunction. We defined perioperative mortality as occurring within 30 days of surgery and early mortality within 90 days.

RESULTS

Twenty-five men and 10 women received lungs, 22 for pulmonary fibrosis and 13 for emphysema; the mean age was 53.26 10.77 years. Twenty right SLTs were performed and 15 left SLTs. Twenty-nine donors were men and 6 were women, with a mean age of 29.31 12.33 years. Twenty-six died from cranial trauma, 8 from stroke and 1 from a brain tumor. The mean time of intubation was 1.69 1.35 days. The mean PaO2 was 470.71 70.82 mmHg. The mean time of ischemia was 201.77 62.64 minutes. Four patients (11.42%) developed PGF and 3 died during the perioperative period. Two additional patients died within the early postoperative period. Survival was 91.4% at one month and 85.5% at three months. The cause of donor death was the only variable that influenced the development of PGF.

CONCLUSION

We observed a low incidence of PGF and of perioperative and early mortality, with one and three month survival rates similar to those reported internationally.

A comparative study of Euro-Collins, low potassium University of Wisconsin and cold modified blood solutions in lung preservation in acute autotransplantations in the pig

OBJECTIVE

The aim of the study was to assess the quality of lung preservation offered by Euro-Collins solution (EC), Cold Modified Blood solution (CMB) and low potassium University of Wisconsin solution (UWLP).

METHOD

Fifteen right lung auto-transplantations (five for each solution) in the pig (Large White) were performed after 2 h of cold ischaemic storage in physiological solution at 4 degrees C. Right lung biopsies were performed before ischaemia and 30 min after reperfusion, for histoenzymatic, histopathological and electron microscope studies.

RESULTS

After reperfusion, significant alterations were observed in the haemodynamics with only the right lung perfused; pulmonary arteriolar resistance increased by a factor of 5 in the EC group, by a factor of 4 in the CMB group and by a factor of 1.2 in the UWLP group; the right ventricular ejection fraction fell by 60% in the EC group, by 50% in the CMB group and by 31% in the UWLP group. Haemodynamic impairment was lower in the UWLP group (P<0.05; P<0.001) as was ischaemic-reperfusion injury (P<0.05). Oedema was observed in the EC group and extensive alveolar wall damage in the CMB group. Hypoxaemia was observed in all groups but the differences in the degree of hypoxaemia were not significant.

CONCLUSIONS

The authors concluded that UWLP solution was the most effective of the three in this transplant model.

[Lesion caused by ischemia-reperfusion in lung transplantation]

OBJECTIVES

To assess the existence or not of a relation between the characteristics of lung donor and/or recipient and the development of ischemia-reperfusion injury (IRI). We also review the latest experimental findings on the biophysical conditions pf graft preservation.

PATIENTS AND METHOD

A retrospective study of 74 lung transplants performed in our hospital from 1993 to 1998. Donor and recipient screening and anesthetic and surgical techniques were performed following established protocols. Various degrees of IRI were determined according to hemodynamic and gasometric criteria. We analyzed the statistical relation between donor and recipient variables and IRI. Statistical significance was set at p < 0.05.

RESULTS

The incidence of IRI was 70.2% (52 cases), with 12 cases categorized as mild, 22 as moderate and 18 as severe. IRI was significantly related only to the start of extracorporeal circulation.

CONCLUSIONS

The development of IRI in lung transplantation is linked to such donor and/or recipient characteristics as the biophysical conditions of graft preservation. At present, greater prevention of this type of early dysfunction of the lung graft requires not only use of adequate screening criteria for donors and receivers but also adequate measures for graft preservation with the use of drugs and handling that have been shown to be effective.

Lung procurement by low-potassium dextran and the effect on preservation injury. Munich Lung Transplant Group

BACKGROUND

This clinical study was performed to evaluate the effect of low-potassium dextran (LPD) solution on organ function in human lung transplantation.

METHODS

A total of 80 patients were included in this study. Donor lungs were flushed with Euro-Collins (EC) solution in 48 cases or LPD (Perfadex) in 32 cases. Subsequently, single- (EC: n = 31; LPD: n = 15) or double-lung transplantations (EC: n = 17; LPD: n = 17) were performed. The evaluation parameters of transplant function were the reperfusion injury score (grade I to V); the alveolar/arterial oxygen ratio; the duration of respirator therapy; and the length of intensive care treatment and survival.

RESULTS

Incidence and severity of reperfusion injury score were more severe in the EC group (31 of 48: grade I: n = 13; II: n = 8; III: n = 5; IV: n = 2; V: n = 3; LPD group: 17 of 32 patients; grade I: n = 12; II: n = 1; III: n = 3; IV: n = 0 grade V: n = 0), leading to death in three patients. In the LPD group, despite of the use of cardiopulmonary bypass, alveolar/arterial oxygen ratio values were significantly (P = 0.009) better during the early postoperative phase. Thirty-day mortality was 12% in the EC group and 6% in the LPD group. The one-year survival rate was 79% after the use of LPD (vs. EC: 62%).

CONCLUSIONS

Graft preservation using LPD leads to better immediate and intermediate graft function after pulmonary transplantation and also results in better long-term survival.

Endothelin-1 induces production of the neutrophil chemotactic factor interleukin-8 by human brain-derived endothelial cells

Increased levels of endothelin-1 (Et-1), a potent vasoconstrictor, have been correlated with hypertension and neuronal damage in ischemic/reperfusion injury. The presence of polymorphonuclear cells (PMNs) in the brain has been shown to be directly responsible for this observed pathology. To address the question of whether Et-1 plays a role in this process, human brain-derived endothelial cells (CNS-ECs) were cultured with Et-1. The results demonstrate that Et-1 induces production of the neutrophil chemoattractant interleukin-8 (IL-8) twofold to threefold after 72 hours; mRNA was maximal after 1 hour of stimulation. Conditioned culture medium derived from Et-1-stimulated CNS-ECs induced a chemotactic response in the PMN migration assay. The inflammatory cytokines tumor necrosis factor-alpha (TNF) and IL-1beta functioned additively with Et-1 in increasing IL-8 production. In contrast, transforming growth factor-beta (TGF-beta), but not IL-10, completely abolished the effect of Et-1 on IL-8 production. However, Et-1 did not modulate intercellular adhesion molecule-1 (ICAM-1) expression. These data demonstrate that Et-1 may be a risk factor in ischemic/reperfusion injury by inducing increased levels of the neutrophil chemoattractant IL-8.

Randomized controlled trial to evaluate flush and reperfusion techniques in liver transplantation

To determine the impact of different flush and reperfusion techniques on postreperfusion syndrome (PRS) and postoperative graft function, 100 transplants were randomly assigned into four groups as follows: group 1 (n=31), portal vein flush, no vena caval venting; group 2 (n=21), hepatic arterial flush, no vena caval venting; group 3 (n=29), portal vein flush with vena caval venting; and group 4 (n=19), hepatic artery flush with vena caval venting. Donor and recipient characteristics were similar. Extensive intraoperative and postoperative monitoring was performed and measurements were documented immediately before reperfusion and at 1, 5, 15, and 30 min after reperfusion. PRS was defined by three criteria: mean arterial pressure (MAP) <60 mmHg at 1 min after reperfusion, MAP <60 mmHg at 5 min after reperfusion, and a decrease of 30% or more for the MAP percent area under the curve during the initial 5 min after reperfusion (%AUC). Using these definitions, the overall incidence of PRS was 21%, 8%, and 43%, respectively. Group 1 was the most hemodynamically stable; the incidence of PRS in group 1 was 2/31 (7%) at 1 min and 8/31 (25%) using %AUC criteria compared with 7/21 (33%) at 1 min and 12/21 (57%) using %AUC criteria for group 2 (P<0.05). The patients in groups 3 and 4 (vena caval venting) demonstrated smaller percentage increases in serum potassium levels (as determined by %AUC; 4.3+/-6.8 and 0.3+/-5.4, vs. 15.1+/-8.1 for group 1 and 22.9+/-8.2 for group 2). The difference between group 4 and group 2 was statistically significant (P<0.05). The increases in serum potassium did not translate into increased cardiac or hemodynamic instability. Combining all data obtained over the first 30 min after reperfusion, there was no statistically significant difference in hemodynamic or biochemical changes noted among the four groups. Postoperative liver function was similar among the four groups. We conclude that portal vein flush without vena caval venting provided a lower incidence of PRS than any other technique. Vena caval venting decreased the release of potassium into the circulation. Postoperative graft function was not significantly affected by flush and reperfusion techniques.

Ischemia: reperfusion syndrome of the lower limbs

The ischemia-reperfusion syndrome, first described by Haimovici in 1960, is a severe complication following surgery for acute ischemia. We evaluated the incidence of this complication in 264 patients operated on between 1972 and 1981 (1st group) and compared it with another of 392 patients operated on between 1982 and 1991 (2nd group), our aim being to assess the effects of pharmacological prophyiaxis based on preoperative overhydration followed by an intra-arterial bolus of 250 ml 14/1000 HCO3-, containing 1 g dexamethasone and 2500 I.U. sodium heparin, injected into the femoral artery before suturing the arteriotomy. This regimen was based on the measurement of myoglobin and glutathione levels respectively carried out in two subgroups of 25 patients. The results of experimental ischemia-reperfusion syndromes induced in animal using radical scavengers and membrane-protective compounds were also taken into consideration. Following experimental research on sheep, 5 patients in the second group with very severe ischemia due to aortic occlusion received local dialysis in the extracorporeal circulation using hemodialysis or hemofiltration techniques. Mortality was 6.3% in the first group and 5.4% in the second, while the amputation rate was 3% and 1.8% respectively. The overall incidence of the reperfusion syndrome was 3% in the 1st period and 1.8% in the second. Our findings confirm the protective effect of hyper-hydration, radical scavengers and dexamethasone in the ischemia reperfusion syndrome, and indicate that local hemodialysis is a useful adjunct in very severe ischemia.

Lung transplant edema: chest radiography after lung transplantation--the first 10 days

PURPOSE

To determine the imaging spectrum and clinical correlates of lung transplant edema within the first 10 days after lung transplantation.

MATERIALS AND METHODS

The study group consisted of 105 consecutive lung transplant recipients. Lung infiltrates on chest radiographs were scored and characterized. Findings that satisfied the accepted description of reperfusion edema were identified. Lung ischemia times and the clinical or biopsy diagnosis of acute rejection were correlated with radiographic findings.

RESULTS

Lung infiltrates compatible with reperfusion edema were seen in 97% of transplanted lungs without a demonstrable correlation with lung ischemia times. Lung scores between groups of patients treated and not treated for acute rejection were not statistically significantly different.

CONCLUSION

The spectrum of findings attributable to lung transplantation or reperfusion edema is variable and diminishes the use of chest radiography as an early postoperative modality for monitoring acute rejection.

Ischemia-reperfusion injury of the spinal cord: protective effect of the hydroxyl radical scavenger dimethylthiourea

PURPOSE

This study was undertaken to evaluate whether neurologic outcome after aortic cross-clamping in rabbits could be improved with perioperative infusion of the hydroxyl radical scavenger dimethylthiourea and, if so, to determine whether it is effective during the period of ischemia, reperfusion, or both.

METHODS

In 41 New Zealand White rabbits, a snare occlusion device was placed at operation around the infrarenal aorta and tunneled into a subcutaneous position. Animals were then allowed to recover and, 48 hours later, randomized into four groups. In each group, the infrarenal aorta was occluded by tightening the snare in the awake animal. In groups 1, 2, and 3, cross-clamp time was 21 minutes. Group 1 (control) animals received saline solution, whereas group 2 (preclamp 21) received dimethylthiourea 750 mg/kg intravenously just before aortic clamping. In group 3 (prerep 21), dimethylthiourea was given just before reperfusion. Group 4 received dimethylthiourea before clamping, with cross-clamp time extended to 31 minutes. A second dose of saline solution or dimethylthiourea was given 12 hours after clamping in controls and the three treatment groups, respectively. Animals were observed for 5 days, and final neurologic recovery was graded by an independent observer. Animals were then killed, and their spinal cords were removed for histologic examination.

RESULTS

Complete paraplegia and marked histologic spinal cord injury at 5 days were seen in 91% (10/11) of group 1 (control) animals, whereas all animals in group 2 (preclamp 21) showed neurologic recovery (p < 0.0001). In group 3 (prerep 21), the final paraplegia rate was 50% (5 of 10), in group 4 (preclamp 31), 100% (10 of 10).

CONCLUSIONS

Our results suggest that hydroxyl radicals play an important role in ischemia-reperfusion injury of the spinal cord and that treatment with dimethylthiourea can prevent paraplegia after 21 minutes of aortic cross-clamping in rabbits.

Amelioration of post-ischemic lung reperfusion injury by prostaglandin E1

To reduce ischemia-reperfusion injury, a number of clinical lung transplant programs employ prostaglandin E1 (PGE1) or prostacyclin (PGI2) before donor lung flush and harvest. The effect of prostaglandins on the reperfusion component of this ischemia-reperfusion complex is unknown. We investigated the effect of PGE1 given only during the period of reperfusion, on ischemic lung injury in an in situ rabbit model. To examine the mechanisms involved, we measured pulmonary hemodynamics as well as myeloperoxidase, circulating platelet, and tumor necrosis factor (TNF) values. Two hours of warm ischemia of the left lung was produced in anesthetized New Zealand white rabbits. The animals were randomly allocated into four groups based on treatment received only during reperfusion: PGE1, PGI2, nitroprusside (NP), or no treatment (controls). After 2 h of reperfusion, PaO2 in the PGE1 group was significantly higher (423 +/- 52.7 mm Hg) than in all other groups (PGI2, 239 +/- 43.4, p < 0.05; NP, 146 +/- 14.2 p < 0.01; controls, 74 +/- 19.1 mm Hg, p < 0.01), despite similar pulmonary vascular resistance in the PGE1 and NP groups. Although lower than in the PGE1 group, PaO2 in the PGI2 group was still significantly higher than that in controls. Wet/dry lung weight ratios were significantly lower in the PGE1 and PGI2 groups (6.5 +/- 0.2 [p < 0.01] and 6.9 +/- 0.6 [p < 0.05], respectively, versus 8.2 +/- 0.1 in controls). There were no significant differences in plasma TNF levels, platelet sequestration across the lungs, or lung myeloperoxidase activity in the four groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in cerebral hemodynamics and oxygenation in the first 24 hours after birth asphyxia

OBJECTIVE

To investigate whether or not postasphyctic cerebral hypoperfusion and decreased cerebral metabolism occur in the perinatally asphyxiated neonate, as has been reported in adults and newborn animals.

METHODS

Using near-infrared spectroscopy, we monitored changes in oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), total hemoglobin (HbO2 + HbR, which represents changes in cerebral blood volume [CBV]), and cytochrome oxidase (Cytaa3, which indicates changes in oxidation level of this intracerebral mitochondrial enzyme). Thirty-one neonates (gestational age > 34 weeks), divided into three groups, were monitored between 2 and 12 hours or between 12 and 24 hours of life. Group I consisted of healthy newborns: N = 8 (2 to 12 hours) and N = 5 (12 to 24 hours). Patients in group II were moderately asphyxiated newborns but neurologically normal in the first 24 hours of life: N = 6 (2 to 12 hours) and N = 3 (12 to 24 hours). Group III consisted of severely asphyxiated newborns with an abnormal neurologic behavior within 24 hours after birth: N = 5 (2 to 12 hours) and N = 4 (12 to 24 hours).

RESULTS

From 2 to 12 h, CBV levels in groups I and II were stable. In group III CBV decreased in all infants. This decrease in CBV was associated with a drop in both HbO2 and HbR. Cytaa3 was stable in groups I and II, but showed a marked decrease in two of the five infants of group III. There was a positive relationship between CBV and mean arterial blood pressure in groups II and III. Between 12 and 24 hours, all groups showed stable CBV and Cytaa3 patterns. A positive relation existed now between transcutaneous PCO2 and CBV in groups II and III.

CONCLUSIONS

CBV, HbO2, HbR, and Cytaa3 decreased in the first 12 hours of life in severely asphyxiated neonates who subsequently developed neurologic abnormalities. We therefore suggest that posthypoxic-ischemic reperfusion injury of the brain during early neonatal life occurs in neonates with severe birth asphyxia.

The reflush effect--a prospective analysis of late perfusion

This prospective randomized trial examines the effect of a "reflush" with preservation solution immediately prior to renal allograft implantation, using hyperosmolar citrate (HOC, n = 10) or phosphate-buffered sucrose (PBS140, n = 10) versus no reflush (n = 10). All kidneys had been stored in HOC. The HOC reflush did not alter the postpreservation intra- or extracellular electrolyte milieu, whereas the PBS140 reflush resulted in an apparent overall loss of both sodium and potassium from the kidney (P < 0.0005). A small amount of calcium was released into the venous effluent in both reflush groups. A similar amount of lactic acid was released into the venous effluent of the two reflush groups, reflected by a lower pH (P < 0.0005), and there was a similar loss of lactate dehydrogenase and creatine phosphokinase. An analysis of procoagulant activity in the first urine produced was performed as a marker of reperfusion injury. The median value was higher in the No Reflush group at 457.5 units, compared with 263.0 and 209.0 units for the PBS140 and HOC Reflush groups, respectively (P = 0.06). Reflushing the kidneys reduced the postoperative dialysis requirement (from 40% to 15%), but by the end of the first posttransplant week there was no significant difference between the renal functional analyses of the three groups, and there was no difference at one year. The proposed mechanism for the early renal functional improvement is a reduction in the calcium paradox and free radical formation, by release of calcium and ATP breakdown products into the venous effluent prior to implantation.