Aorto-right ventricular fistula after transfemoral aortic valve implantation

A 91-year-old female patient presented with worsening exertional dyspnea 1 month after transfemoral aortic valve implantation using an Edwards Sapien valve. She was found to have a paraprosthetic sinus of Valsalva rupture with a left-to-right shunt into the right ventricular cavity. The patient underwent coil closure of the defect with successful shunt elimination.

Impact of percutaneous patent foramen ovale closure on migraine course

Migraine is a neurological disorder characterized by an increased individual susceptibility to respond to certain triggers by a propagating wave of neuronal depolarization that culminates in typical migraine headaches. Patients with a patent foramen ovale or any kind of right-to-left shunt are more likely to have migraine; and patients with migraine with aura are more likely to have a patent foramen ovale than patients without migraine. Nonrandomized reports of patent foramen ovale closure in divers, in patients with paradoxical embolism and in migraine patients with ischemic brain lesions have shown an impressive reduction in migraine headaches during follow-up. To date, the only double-blind, randomized controlled trial with a sham procedure in the control arm failed to show any benefit, probably owing to inadequate patient selection and maybe because of a high residual shunt rate. Two other randomized trials continue to enroll patients with migraine with aura and drug-refractory headaches and their results are awaited.

A new tool for frameless stereotactic placement of ventricular catheters

The accurate position of the ventricular catheter inside the frontal horn of the lateral ventricle is essential to prevent proximal failure in shunt surgery. For optimal placement, endoscopic- and image-guided techniques are available.

Plicated patch repair for acquired Gerbode defect involving the tricuspid valve

Gerbode's defect, a left ventricular-to-right atrial communication, with involvement of the tricuspid valve acquired after bacterial endocarditis can be challenging to repair. We report a modified technique for a shunt closure and reconstruction of the tricuspid valve using a plicated bovine pericardial patch. Combining such a repair with a left ventricular patch resulted in a complete defect closure and competent tricuspid valve without regurgitation.

Outer skull landmark-based coordinates for measurement of cerebral blood flow and intracranial pressure in rabbits

Despite the increased use of intracranial neuromonitoring during experimental subarachnoid hemorrhage (SAH), coordinates for probe placement in rabbits are lacking. This study evaluates the safety and reliability of using outer skull landmarks to identify locations for placement of cerebral blood flow (CBF) and intraparenchymal intracranial pressure (ICP) probes. Experimental SAH was performed in 17 rabbits using an extracranial-intracranial shunt model. ICP probes were placed in the frontal lobe and compared to measurements recorded from the olfactory bulb. CBF probes were placed in various locations in the frontal cortex anterior to the coronary suture. Insertion depth, relation to the ventricular system, and ideal placement location were determined by post-mortem examination. ICP recordings at the time of SAH from the frontal lobe did not differ significantly from those obtained from the right olfactory bulb. Ideal coordinates for intraparenchymal CBF probes in the left and right frontal lobe were found to be located 4.6±0.9 and 4.5±1.2 anterior to the bregma, 4.7±0.7mm and 4.7±0.5mm parasagittal, and at depths of 4±0.5mm and 3.9±0.5mm, respectively. The results demonstrate that the presented coordinates based on skull landmarks allow reliable placement of intraparenchymal ICP and CBF probes in rabbit brains without the use of a stereotactic frame.

Influence of fluid and volume state on PaO(2) oscillations in mechanically ventilated pigs

ABSTRACT Varying pulmonary shunt fractions during the respiratory cycle cause oxygen oscillations during mechanical ventilation. In artificially damaged lungs, cyclical recruitment of atelectasis is responsible for varying shunt according to published evidence. We introduce a complimentary hypothesis that cyclically varying shunt in healthy lungs is caused by cyclical redistribution of pulmonary perfusion. Administration of crystalloid or colloid infusions would decrease oxygen oscillations if our hypothesis was right. Therefore, n = 14 mechanically ventilated healthy pigs were investigated in 2 groups: crystalloid (fluid) versus no-fluid administration. Additional volume interventions (colloid infusion, blood withdrawal) were carried out in each pig. Intra-aortal PaO(2) oscillations were recorded using fluorescence quenching technique. Phase shift of oxygen oscillations during altered inspiratory to expiratory (I:E) ventilation ratio and electrical impedance tomography (EIT) served as control methods to exclude that recruitment of atelectasis is responsible for oxygen oscillations. In hypovolemia relevant oxygen oscillations could be recorded. Fluid and volume state changed PaO(2) oscillations according to our hypothesis. Fluid administration led to a mean decline of 105.3 mmHg of the PaO(2) oscillations amplitude (P < 0.001). The difference of the amplitudes between colloid administration and blood withdrawal was 62.4 mmHg in pigs not having received fluids (P = 0.0059). Fluid and volume state also changed the oscillation phase during altered I:E ratio. EIT excluded changes of regional ventilation (i.e., recruitment of atelectasis) to be responsible for these oscillations. In healthy pigs, cyclical redistribution of pulmonary perfusion can explain the size of respiratory-dependent PaO(2) oscillations.

A review of full-body radiography in nontraumatic emergency medicine

This paper reports on the application of full-body radiography to nontraumatic emergency situations. The Lodox Statscan is an X-ray machine capable of imaging the entire body in 13 seconds using linear slit scanning radiography (LSSR). Nontraumatic emergency applications in ventriculoperitoneal (VP) shunt visualisation, emergency room arteriography (ERA), detection of foreign bodies, and paediatric emergency imaging are presented. Reports show that the fast, full-body, and low-dose scanning capabilities of the Lodox system make it well suited to these applications, with the same or better image quality, faster processing times, and lower dose to patients. In particular, the large format scans allowing visualisation of a greater area of anatomy make it well suited to VP shunt monitoring, ERA, and the detection of foreign bodies. Whilst more studies are required, it can be concluded that the Lodox Statscan has the potential for widespread use in these and other nontraumatic emergency radiology applications.

Congenital hypothyroidism in a kitten resulting in decreased IGF-I concentration and abnormal liver function tests

A 7-month-old male kitten was presented with chronic constipation and retarded growth. Clinical examination revealed disproportional dwarfism with mild skeletal abnormalities and a palpable thyroid gland. The presumptive diagnosis of congenital hypothyroidism was confirmed by low serum total thyroxine (tT(4)) concentration prior to and after the administration of thyroid stimulation hormone (TSH), increased endogenous TSH concentration and abnormal thyroid scintigraphic scan. The kitten had abnormal liver function tests and decreased insulin-like growth factor 1 (IGF-1) concentration, both of which returned to normal in correspondence with an improvement of the clinical signs after 6 weeks of thyroxine therapy. Congenital hypothyroidism is a rare disease that may present with considerable variation in clinical manifestation. In cases in which clinical signs are ambiguous, disorders such as portosystemic shunt and hyposomatotropism have to be taken into account as differential diagnosis. As hypothyroidism may be associated with abnormal liver function tests and low IGF-1 concentrations, test results have to be interpreted carefully.

Cranioplasty after decompressive craniectomy: the effect of timing on postoperative complications

Decompressive craniectomy (DC) due to intractably elevated intracranial pressure mandates later cranioplasty (CP). However, the optimal timing of CP remains controversial. We therefore analyzed our prospectively conducted database concerning the timing of CP and associated post-operative complications. From October 1999 to August 2011, 280 cranioplasty procedures were performed at the authors' institution. Patients were stratified into two groups according to the time from DC to cranioplasty (early, ≤2 months, and late, >2 months). Patient characteristics, timing of CP, and CP-related complications were analyzed. Overall CP was performed early in 19% and late in 81%. The overall complication rate was 16.4%. Complications after CP included epidural or subdural hematoma (6%), wound healing disturbance (5.7%), abscess (1.4%), hygroma (1.1%), cerebrospinal fluid fistula (1.1%), and other (1.1%). Patients who underwent early CP suffered significantly more often from complications compared to patients who underwent late CP (25.9% versus 14.2%; p=0.04). Patients with ventriculoperitoneal (VP) shunt had a significantly higher rate of complications after CP compared to patients without VP shunt (p=0.007). On multivariate analysis, early CP, the presence of a VP shunt, and intracerebral hemorrhage as underlying pathology for DC, were significant predictors of post-operative complications after CP. We provide detailed data on surgical timing and complications for cranioplasty after DC. The present data suggest that patients who undergo late CP might benefit from a lower complication rate. This might influence future surgical decision making regarding optimal timing of cranioplasty.

Experience with a gravitational valve in the management of symptomatic overdrainage in children with shunts

Symptomatic overdrainage in children with shunt-treated hydrocephalus represents one of the more difficult shunt-related diseases and may require repeated surgery. Gravity-assisted valve design has become a standard device to avoid overdrainage in many European pediatric hydrocephalus centers. However, the use of a gravitational valve for relieving symptoms associated with overdrainage has not yet been addressed. The goal of this study was to evaluate the effectiveness of a gravitational valve in the treatment of symptomatic overdrainage in children with shunts.

Connective tissue growth factor level is increased in patients with liver cirrhosis but is not associated with complications or extent of liver injury

Connective tissue growth factor (CTGF) is a profibrotic protein whose systemic levels are increased in liver cirrhosis. Here, association of CTGF with stages of liver injury and complications of cirrhotic liver disease has been analyzed in patients with different aetiologies of hepatic injury. CTGF is significantly increased in portal venous serum (PVS), hepatic venous serum (HVS) and systemic venous serum (SVS) of 46 patients with liver cirrhosis compared to eight liver-healthy controls. In patients´ blood samples CTGF in HVS is about 6% higher than PVS levels indicating that CTGF produced in the liver is released to the circulation. CTGF is not associated with stages of liver cirrhosis defined by CHILD-PUGH or MELD score nor with secondary complications of portal hypertension (varices, ascites, spontaneous bacterial peritonitis). Transforming growth factor β (TGFβ) induces CTGF synthesis in hepatocytes and a positive association of systemic TGFβ1 and SVS and HVS CTGF is found. Three months after placing transjugular intrahepatic portosystemic shunt (TIPS) hepatic venous pressure gradient is reduced whereas CHILD-PUGH score, TGFβ1 and CTGF are not altered in serum of 15 patients. Current data show that the cirrhotic liver releases little CTGF but SVS, HVS and PVS CTGF levels are not associated with residual liver function and complications of cirrhosis.

Respiratory function during anesthesia: effects on gas exchange

Anaesthesia causes a respiratory impairment, whether the patient is breathing spontaneously or is ventilated mechanically. This impairment impedes the matching of alveolar ventilation and perfusion and thus the oxygenation of arterial blood. A triggering factor is loss of muscle tone that causes a fall in the resting lung volume, functional residual capacity. This fall promotes airway closure and gas adsorption, leading eventually to alveolar collapse, that is, atelectasis. The higher the oxygen concentration, the faster will the gas be adsorbed and the aleveoli collapse. Preoxygenation is a major cause of atelectasis and continuing use of high oxygen concentration maintains or increases the lung collapse, that typically is 10% or more of the lung tissue. It can exceed 25% to 40%. Perfusion of the atelectasis causes shunt and cyclic airway closure causes regions with low ventilation/perfusion ratios, that add to impaired oxygenation. Ventilation with positive end-expiratory pressure reduces the atelectasis but oxygenation need not improve, because of shift of blood flow down the lung to any remaining atelectatic tissue. Inflation of the lung to an airway pressure of 40 cmH2O recruits almost all collapsed lung and the lung remains open if ventilation is with moderate oxygen concentration (< 40%) but recollapses within a few minutes if ventilation is with 100% oxygen. Severe obesity increases the lung collapse and obstructive lung disease and one-lung anesthesia increase the mismatch of ventilation and perfusion. CO2 pneumoperitoneum increases atelectasis formation but not shunt, likely explained by enhanced hypoxic pulmonary vasoconstriction by CO2. Atelectasis may persist in the postoperative period and contribute to pneumonia.

[Oesophageal and fundic variceal bleeding]

Oesophageal and fundic varices belong to the most frequent complications of cirrhosis and portal hypertension. Due to their significant morbidity and mortality, bleedings from oesophageal or fundic varices represent a challenge for the emergency medical team as well as for the gastroenterologist. The patient with a variceal bleeding should be accurately monitored and his/her hemodynamic parameters should be maintained stable with the administration of plasma expanders and blood units when indicated. An antibiotic prophylaxis in this setting--norfloxacin or ceftriaxon--has been demonstrated to significantly reduce morbidity and mortality. Additionally, the early administration of vasoactive compounds, such as terlipressin, somatostatin or octreotide, is associated with beneficial effects in reducing the bleeding. An upper gastrointestinal endoscopy should be generally performed within the first twelve hours from the beginning of the bleeding in order to obtain an accurate diagnosis and to provide an adequate treatment. Endoscopic procedures to control the bleeding include the rubber band ligation, the treatment of the varix with a sclerosing agent or the injection of tissue glue into the varix. In case of recurrent bleeding, beyond the above methods, different techniques, such as the transjugular porto-caval shunt, surgical shunt procedures, as well as embolisation of splanchnic blood vessels, represent additional therapeutic options. However, they are associated with very high mortality rates and their indication has to be discussed case by case by an interdisciplinary team of experts. Future therapies include the optimisation and the improvement of the current medical and endoscopic armamentarium, as well as the application of treatments to novel targets, such as the coagulation cascade.

The hepato-pulmonary syndrome--where do we stand in the year 2006?

The hepato-pulmonary syndrome (HPS) is characterized by a combination of liver disease and pulmonary gas exchange abnormalities with arterial hypoxemia, intrapulmonary vasodilatation and arteriovenous shunting in the absence of intrinsic cardiopulmonary disease. The course of the disease is typically progressive. The mortality rate correlates with the pulmonary shunt volume and the degree of hypoxemia at room air. While the patho-physiology of HPS is still not fully understood, a multifactorial etiology is favored. Apart from functional intrapulmonary arteriovenous shunts which appear to represent a major factor in the development of HPS, both ventilation-perfusion mismatch and limited oxygen diffusion contribute to the HPS. Regarding its clinical appearance, pulmonary and hepatic symptoms have to be distinguished. Contrast echocardiography is the primary diagnostic tool. Symptomatically, hypoxemia can be treated with oxygen. So far, the only successful treatment approach which has been tested in larger patient groups, is liver transplantation. Given this background, the aim of this review is to critically discuss current concepts of this serious complication of liver diseases.

Biofilm-related infections of cerebrospinal fluid shunts

Cerebrospinal fluid (CSF) shunts carry a high risk of complications. Infections represent a major cause of shunt failure. Diagnosis and therapy of such infections are complicated by the formation of bacterial biofilms attached to shunt surfaces. This study correlated the pathophysiology and clinical course of biofilm infections with microscopical findings on the respective shunts. Surface irregularities, an important risk-factor for shunt colonisation with bacteria, were found to increase over time because of silicone degradation. Scanning electron-microscopy (SEM) documented residual biological material (dead biofilm), which can further promote extant bacterial adhesion, on newly manufactured shunts. Clinical course and SEM both documented bacterial dissemination against CSF flow and the monodirectional valve. In all cases, biofilms grew on both the inner and outer surfaces of the shunts. Microscopy and conventional culture detected all bacterial shunt infections. Analyses of 16S rDNA sequences using conserved primers identified bacteria in only one of three cases, probably because of previous formalin fixation of the samples.