Stefania Barbieri

Perioperative thrombotic complications in liver transplantation

Although the perioperative bleeding complications and the major side effects of blood transfusion have always been the primary concern in liver transplantation (OLT), the possible cohesion of an underestimated intrinsic hypercoagulative state during and after the transplant procedure may pose a major threat to both patient and graft survival. Thromboembolism during OLT is characterized not only by a complex aetiology, but also by unpredictable onset and evolution of the disease. The initiation of a procoagulant process may be triggered by various factors, such as inflammation, venous stasis, ischemia-reperfusion injury, vascular clamping, anatomical and technical abnormalities, genetic factors, deficiency of profibrinolytic activity, and platelet activation. The involvement of the arterial system, intracardiac thrombosis, pulmonary emboli, portal vein thrombosis, and deep vein thrombosis, are among the most serious thrombotic events in the perioperative period. The rapid detection of occlusive vascular events is of paramount importance as it heavily influences the prognosis, particularly when these events occur intraoperatively or early after OLT. Regardless of the lack of studies and guidelines on anticoagulant prophylaxis in this setting, many institutions recommend such an approach especially in the subset of patients at high risk. However, the decision of when, how and in what doses to use the various chemical anticoagulants is still a difficult task, since there is no common consensus, even for high-risk cases. The risk of postoperative thromboembolism causing severe hemodynamic events, or even loss of graft function, must be weighed and compared with the risk of an important bleeding. In this article we briefly review the risk factors and the possible predictors of major thrombotic complications occurring in the perioperative period, as well as their incidence and clinical features. Moreover, the indications to pharmacological prophylaxis and the current treatment strategies are also summarized.

Epidural Anesthesia and Analgesia in Liver Resection and Living Donor Hepatectomy

Parenteral analgesics are still diffusely administered for postoperative pain after major liver resection, while epidural analgesia is widely criticized because of possible changes in the postoperative coagulation profile. The safety of regional anesthesia in liver resections is based on appropriate timing of needle placement and catheter removal and on the individuals skill in performing both the puncture and the catheterization. In the absence of liver failure or in cases of only moderate hepatic dysfunction, the risk of neurologic complications and spinal hematomas does not appear greater than when an epidural is performed for routine abdominal or thoracic surgery. Various anesthetic strategies have been adopted to prevent bleeding during liver resection, such as fluid restriction, diuretic administration, and vasodilator drugs. Lowering central venous pressure (CVP) seems to play a prominent role in prevention of bleeding since an elevated CVP may be associated with increased blood loss at various phases of liver resection. However, a low CVP may not be tolerated by all patients: intraoperative hemodynamic instability may, in fact, easily ensue because of the cardiovascular depressant effects of anesthetics, surgical blood losses, and manipulation of the inferior vena cava. We suggest combining intraoperative epidural anesthesia with general (light) anesthesia as a useful strategy to keep the CVP low during liver resection without vasodilators or diuretics. Epidural anesthesia does not lead to changes in intravascular volume, but only promotes redistribution of blood, decreasing both venous return and portal vein pressure, thus contributing to reduced hepatic congestion and surgical blood loss.

Risk factors for central pontine and extrapontine myelinolysis after liver transplantation: A single-center study

Background Central pontine and extrapontine myelinolysis (CPM/EPM) are severe neurologic complications after liver transplantation. Methods The present work retrospectively evaluated single-center prevalence of CPM/EPM and associated risk factors: cause of liver disease, hepatic encephalopathy, preoperative, intraoperative, and perioperative blood components use, serum levels, and variation of Na+, Cl−, and K+ and immunosuppression were compared between CPM/EPM patients and control group of transplanted patients without neurologic complications. Results Among 997 transplants, CPM/EPM were diagnosed in 11 patients (1.1%), of whom four were CPM, one was EPM, and six were associated CPM and EPM. Control group consisted of 44 transplanted patients. Central pontine and extrapontine myelinolysis patients experienced higher intraoperative and perioperative serum Na+/24 hr variations compared to controls (16.69±5.17 vs. 9.8±3.4 mEq/L, P = 0.001). Maximum peak of intraoperative or perioperative serum Na+ was significantly higher in patients compared to controls (151.5±3.3 vs. 140.8±6.2 mEq/L, P⩽0.001), but no difference in preoperative serum Na+ was detected. Three patients presented hypernatremia as isolated risk factor. Conclusion Extrapontine myelinolysis can be found isolated or associated with CPM in up to two of three liver transplanted patients with myelinolysis. A marked variation of perioperative serum Na+ remains the main risk factor even in patients without preexisting hyponatremia; however, isolated hypernatremia may be solely responsible in some cases.

Anesthetic considerations for nontransplant procedures in lung transplant patients

Lung transplantation has become an accepted option for many patients with end-stage pulmonary diseases. Anesthesia and surgery following lung transplantation may be required for various diseases that may affect both systemic organs and the transplanted graft. When a patient with a lung transplant undergoes surgery, there is the potential for interference with lung function, depending on the type of intervention and its anatomical site. Accurate preoperative evaluation, an understanding of the physiology of the transplanted lung, proper airway instrumentation, individualized management of intraoperative ventilation, and fluid balance are essential for a positive perioperative outcome.

Prehospital airway management with the laryngeal mask airway in polytraumatized patients

In Italy, as in most industrialized countries, trauma represents the first cause of death in populations aged less than 40 years, and the third overall cause of death in every age group, with an incidence of about 120 cases for every 100,000 inhabitants.1 Traumatic events (road, industrial or domestic accidents, or assaults) inflict an enormous social cost due to the fact that they often affect patients in the most productive age groups. Furthermore, in many injured patients, disabling conditions remain permanent, aggravating the negative consequences on both a human level and a social level. The distribution curve of trauma deaths appears to demonstrate a three-part pattern. The first peak concerns deaths happening within a few seconds or minutes of the traumatic event. The causes are such things as severe cranial and spinal injuries and lacerations of the great vessels—injuries that are life-threatening and usually quickly fatal in spite of the actual level of medical technology available. These are unavoidable deaths, and as a consequence an increase in survival under such circumstances can be achieved only through the adoption of preventive measures. The second peak of mortality incidence finds its place in the first hours after trauma. It concerns primarily hypoxia and hypovolemia deriving from injuries to the viscera and vessels that are potentially lethal but can often be managed through rapid treatment.2,3 Finally, the third peak, chronologically located after some days and weeks from the trauma, concerns all deaths caused by multiorgan insufficiency, infections, and multiple functional inability. Timely and appropriate management of the airway is of fundamental importance in the prevention of the second peak of mortality. It is likely that alternatives to the endotracheal tube, such as the laryngeal mask airway (LMA), can be extremely important when, for whatever reason, it is not possible to carry out laryngoscopy or proceed with a blind endotracheal intubation of the patient. This article reports six cases of difficult intubation in polytraumatized patients where laryngoscopy was unsuccessful. In each of these cases an LMA was rapidly inserted on scene by the anesthesiologist of Padua’s SUEM 118 (Servizio Urgenza Emergenza Medica, Medical Urgency and Emergency Service).

Central Nervous System Infectious Complications Early After Liver Transplantation

Infectious complications contribute to significant patient morbidity and mortality in orthotopic liver transplant (OLT) recipients. Early central nervous system (CNS) involvement (within the first month after OLT) by infectious disease is essentially set off by aggressive surgical procedures, severe morbid conditions of the pretransplant period, initial graft dysfunction, permanence of intravascular catheters, and prolonged mechanical ventilation. The type and severity of CNS infection may be determined by many factors, such as posttransplant adverse events; prolonged or repeated surgery with massive intraoperative transfusions, net state of immunosuppression, recurrence of infections by immunomodulating viruses, and retransplantation. Bacteria, viruses, and fungi can spread to the CNS just as they affect the abdomen, blood stream, respiratory tract, urine, drainages, etc. Because immunosuppressive drugs may modify the clinical presentation of CNS infections, it is very important to maintain vigilance and attend to minor neurologic symptoms. Special attention should therefore be given to cerebral investigation in patients with prolonged pulmonary contamination, unresponsive fever, and heavy corticosteroid therapy, primarily when they became disoriented, develop seizures, or exhibit focal neurologic signs. Clinical response to medical therapy may sometimes be poor because of chronic encapsulation of the pathogen, development of resistance, and/or catastrophic hemorrhagic complications.

Hemodynamic profile of portopulmonary hypertension

Portopulmonary hypertension (PPHTN) refers to the development of pulmonary arterial hypertension in the setting of portal hypertension with or without chronic hepatic failure. This syndrome is characterized by marked alternations of pulmonary vascular tone and obstruction of pulmonary arterial blood flow. An increased pulmonary blood flow, which is a hallmark of the hyperdynamic circulation of cirrhotic patients, seems to be present in almost all patients who develop PPHTN. The elevations of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) along with the transpulmonary gradient (TPG) have been considered in diagnosing PPHTN. Only a high TPG reflects the severity of obstruction to pulmonary blood flow and differentiates an elevated PAP with concomitant elevated PVR from the situation where the increase in PAP is due only to the hyperdynamic flow and elevated volume. A considerable risk for cardiovascular death arises when PAP increases significantly; this may occur in rapidly evolving syndromes, in very advanced disease, or during a complicated liver transplantation. The distinction between PPHTN and elevated PAP in the context of a hyperdynamic state is of great importance; a PAP increase of hyperkinetic origin, as opposed to PPHTN, is apparently not associated with a high risk for adverse effects during and following liver transplantation.

Noninvasive Ventilation in Postoperative Care of Lung Transplant Recipients

Noninvasive positive pressure ventilation (NIPPV), which provides consolidated treatment of both acute and chronic respiratory failure, is increasingly being used in the postoperative care of lung transplant patients. Graft- and patient-related respiratory insufficiency requiring mechanical ventilation are common features in the postoperative period; they may persist for hours to days. Prolonged intubation, particularly in these immunocompromised patients, has been considered one of the main predisposing factors for developing nosocomial pneumonia. It has been associated with increased length of intensive care unit (ICU) stay as well. Noninvasive mechanical ventilation is nowadays an attractive choice to shorten weaning time and avoid reintubation following lung transplantation. Rapid extubation plus prompt NIPPV application is a useful strategy for lung recipients who do not completely fulfill the criteria for safe extubation. Unloading respiratory muscles, decreasing respiratory rate and sensation of dyspnea, improving ventilation/perfusion abnormalities, decreasing the heart rate, and improving hemodynamics are among the recognized benefits. Adding a noninvasive inspiratory support plus positive end-expiratory pressure (PEEP) to lung transplant recipients has been helpful to prevent airway injury and infections, avoiding the need for reintubation in cases of extubation failure, facilitating nocturnal sedation, treating the post-reimplantation syndrome and postoperative phrenic nerve dysfunction, and preventing reintubation in cases of readmission to the ICU. In our practice, the helmet system has emerged as the preferred interface; in cases of dyshomogeneous dorsobasal lung infiltrates, it allows effective ventilatory support in the prone position as well.

Noninvasive Ventilation in Adult Liver Transplantation

Noninvasive ventilation (NIV) has proven to be a safe and effective technique in the treatment of respiratory failure complicating various medical and surgical diseases. In recent years, a growing interest has emerged in its adoption for ventilatory assistance in immunocompromised patients, such as those undergoing bone marrow, liver, lung, cardiac, and kidney transplantation. Weaning from the ventilator after liver transplantation can take longer because of unsatisfactory gas exchange during various attempts of T-piece trials. Rapid extubation followed by an immediate NIV application should be considered in this setting to shorten and accelerate the weaning process in those recipients who do not completely fulfill the criteria for safe extubation. By adding the pressure support (PS) mode with a continuous positive end expiratory pressure (PEEP), NIV could prevent the loss of vital capacity and impede severe lung derecruitment following extubation. Clinical experience has shown that properly delivered NIV mostly benefits moderately dyspneic recipients in acute respiratory failure, while it appears less promising and efficient in patients ventilated for extended periods of time. It has proven safe and efficient mainly as (1) a tool to promote an early ventilatory discontinuation and extubation; (2) a prophylactic strategy for preventing postoperative pulmonary complications; and (3) a simple method to start with in cases of acute hypoxic and/or hypercapnic respiratory failure. The improvements in arterial hypoxemia, the decreased ventilatory demand provided with an inspiratory support, as well as the scarcity of hemodynamic repercussions are among the major benefits of this method.

Liver Autotransplantation for the Treatment of Unresectable Hepatic Metastasis: An Uncommon Indication—A Case Report

Ex situ ex vivo liver surgery represents a method to expand the surgical indications to treat otherwise unresectable liver tumors. We report the case of a 38-year old woman with hepatic metastasis from a pancreatoblastoma that was judged to be unresectable due to the involvement of the three hepatic veins. To treat the primary tumor, she underwent a pancreaticoduodenectomy, adjuvant chemotherapy, and thermal ablation of a liver metastasis. After appropriate preoperative study and with the permission of the ethics committee, she underwent ex situ ex vivo liver resection. The hepatectomy was performed by removing the whole liver en bloc with the retrohepatic vena cava. The inferior vena cava was reconstructed by interposition of a prosthetic graft. The ex situ ex vivo hepatic resection, a left hepatic lobectomy included the lesion in segments 1-5-7-8. The two hepatic veins were reconstructed using patches of saphenous vein. The organ was preserved continuously for 6 hours using hypothermic perfusion with 4°C Celsior solution. The liver was then reimplanted performing an anastomosis between the reconstructed hepatic veins and the caval prostheses. The patient was discharged at postoperative day 22 and is currently disease-free at 8 months after surgery and 44 months after the initial diagnosis. Ex situ, ex vivo liver surgery offers an additional option for patients with both primary and secondary liver tumors considered to be unresectable using traditional surgical approaches.