Mid-term Results of Chimney and Periscope Grafts in Supra-aortic Branches in High Risk Patients.

PURPOSE: Report mid-term outcomes of thoracic endovascular aneurysm repair (TEVAR) with chimney and periscope grafts (CPG) in supra-aortic branches (SAB). METHODS: Retrospective analysis, from October 2009 to May 2014, of patients with aneurysms requiring TEVAR with zone 0/1/2 proximal landing in association with at least one CPG in the SAB. All patients were considered at high risk for conventional surgery. Peri-operative mortality and morbidity, retrograde type A dissection, maximum aortic transverse diameter (TD) and its post-operative evolution, endoleak, survival, freedom from cardiovascular re-interventions, and CPG freedom from occlusion during the follow-up were analysed. RESULTS: Forty-one patients (28.05% EuroScore II) with thoraco-abdominal aortic aneurysm (17%), arch aneurysm (39%), descending aneurysm (34%), and aneurysm extending from the arch to the visceral aorta (10%) were included. Fifteen (37%) patients were treated non-electively. Fifty-nine SABs were treated with the CPG technique: one, two, three, and four CPG were employed in 71%, 19%, 5%, and 5% of patients, respectively. The proximal landing was in zone 0 in 49% of patients, zone 1 in 17%, and zone 2 in 34%. Technical success was 95%. Peri-operative complications and neurological events were registered in six (14.6%) patients and there were 5 deaths (12%). At a median follow-up of 21.2 (mean 22, SD 18; range 0-65) months, type I/III endoleaks were registered in three (7%) cases and re-intervention in six (15%) patients. A significant aneurysm sac shrinkage (p<.001) was reported at mean follow-up and no significant aneurysm sac increase (>5 mm). The estimated 2 year survival, freedom from re-intervention, freedom from endoleak, and freedom from branch occlusion were 75%, 77%, 86%, and 96%, respectively. CONCLUSION: The chimney and periscope grafts technique was shown to be safe in aortic aneurysm disease involving the supra aortic branches, even in an emergency setting using off the shelf devices. Mid-term follow-up results in this high risk population are good, but longer follow-up is mandatory before this technique is used in intermediate-risk patients.

Postconditioning with a volatile anaesthetic in alveolar epithelial cells in vitro.

Acute lung injury is a common complication in critically ill patients. The present study examined possible immunomodulating effects of the volatile anaesthetic sevoflurane on lipopolysaccharide (LPS)-stimulated alveolar epithelial cells (AEC) in vitro. Sevoflurane was applied after the onset of injury, simulating a "postconditioning" scenario. Rat AEC were stimulated with LPS for 2 h, followed by a 4-h co-exposure to a CO(2)/air mixture with sevoflurane 2.2 volume %; control cells were exposed to the CO(2)/air mixture only. Cytokine-induced neutrophil chemoattractant-1, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, as well as the potential protective mediators inducible nitric oxide synthase (iNOS)2 and heat shock protein (HSP)-32, were analysed. Additionally, functional assays (chemotaxis, adherence and cytotoxicity assay) were performed. A significant reduction of inflammatory mediators in LPS-stimulated, sevoflurane-exposed AEC was found, leading to reduced chemotaxis, neutrophil adherence and neutrophil-induced AEC killing. While iNOS2 was increased in the sevoflurane group, blocking experiments with iNOS2 inhibitor did not affect sevoflurane-induced decrease of inflammatory mediators and AEC killing. Interestingly, sevoflurane treatment also resulted in an enhanced expression of HSP-32. The data presented in the current study provide strong evidence that anaesthetic postconditioning with sevoflurane mediates cytoprotection in the respiratory compartment in an in vitro model of acute lung injury.

Hypoxia attenuates effector-target cell interaction in the airway and pulmonary vascular compartment.

Leucocyte infiltration is known to play an important role in hypoxia-induced tissue damage. However, little information is available about hypoxia and interaction of effector (neutrophils) with target cells (alveolar epithelial cells, AEC; rat pulmonary artery endothelial cells, RPAEC). The goal of this study was to elucidate hypoxia-induced changes of effector-target cell interaction. AEC and RPAEC were exposed to 5% oxygen for 2-6 h. Intercellular adhesion molecule-1 (ICAM-1) expression was determined and cell adherence as well as cytotoxicity assays were performed. Nitric oxide and heat shock protein 70 (HSP70) production was assessed in target cells. Under hypoxic conditions enhanced ICAM-1 production was found in both cell types. This resulted in an increase of adherent neutrophils to AEC and RPAEC. The death rate of hypoxia-exposed target cells decreased significantly in comparison to control cells. Nitric oxide (NO) concentration was enhanced, as was production of HSP70 in AEC. Blocking NO production in target cells resulted in increased cytotoxicity in AEC and RPAEC. This study shows for the first time that target cells are more resistant to effector cells under hypoxia, suggesting hypoxia-induced cell protection. An underlying mechanism for this phenomenon might be the protective effect of increased levels of NO in target cells.

Flow rate, syringe size and architecture are critical to start-up performance of syringe pumps.

BACKGROUND AND OBJECTIVE: Significant start-up delays are inherent to syringe infusion pumps, particularly at low infusion rates, as routinely used in children's anaesthesia and intensive care. Such delays are mainly the result of engagement of gears in the mechanical drive or compliance of the syringe assembly. The purpose of the present study was to determine the effect of flow rate, syringe size and syringe architecture on fluid delivery during infusion start-up. METHODS: Elapsed time from infusion start to achievement of steady-state flow was gravimetrically determined for various infusion rates (0.1, 0.5, 1 mL h-1), different syringe sizes (10-, 20-, 30-, 50-mL) and syringes of two different brands (BD and Codan). Four measurements for each condition were performed with two identical Alaris Asena GH syringe infusion pumps (total of eight experiments). Statistical analysis was done by two-way ANOVA with Bonferroni's post-test; P < 0.05 was considered significant. RESULTS: Start-up time was from 3.6 +/- 0.9 min (BD 10-mL syringe, 1.0 mL h-1) to 74.5 +/- 26.6 min (BD 50-mL syringe, 0.1 mL h-1). Overall, the start-up time markedly increased with lower flow rate (0.1 mL h-1 vs. 1 mL h-1; P < 0.0001), larger syringe size (50 mL vs. 10 mL; P < 0.01), and the BD brand in comparison with the Codan syringes (P < 0.01). CONCLUSIONS: Highest possible flow rate, smaller sized syringes and syringe plungers with reduced compressibility should be preferred in order to avoid significant start-up delays in fluid delivery.

Accurate continuous drug delivery at low infusion rate with a novel microvolumetric infusion pump (MVIP): pump design, evaluation and comparison to the current standard.

Infusion devices for continuous and precise drug administration are indispensable tools in anaesthesia and critical care medicine. Problems such as start-up delays, non-continuous flow and susceptibility to hydrostatic pressure changes at low infusion rates resulting in accidental bolus release or prolonged flow interruption are inherent to current infusion technology. In order to improve precise drug delivery, an innovative technical concept has been realised in a novel microvolumetric infusion pump (MVIP) device. The MVIP principle includes repeated filling and emptying of a non-compliant microsyringe without the use of valves. The performance of the MVIP prototype has been evaluated and compared with standard syringe infusion pump assemblies. The novel MVIP concept has thereby proven to eliminate most problems during infusion start-up, steady state flow and vertical pump displacement, and has the potential of revolutionising infusion technology and setting a new dimension in patient safety.

Warming of infusion syringes caused by electronic syringe pumps.

PURPOSE: To evaluate inadvertent warming of the infusion syringe in four different types of electronic syringe pumps. METHODS: Ambient temperature and syringe surface temperature were simultaneously measured by two electronic temperature probes in four different models of commercially available syringe pumps. Experiments were performed at an infusion rate of 1 ml h(-1) using both battery-operated and main power-operated pumps. Measurements were repeated four times with two pumps from each of the four syringe pump types at a room temperature of approximately 23 degrees C. Differences among the four syringe pump brands regarding ambient to syringe temperature gradient were compared using ANOVA. A P-value of less than 0.05 was considered statistically significant. RESULTS: Syringe warming differed significantly between the four syringe brands for both the battery-operated and main power-operated mode (ANOVA, P< 0.001 for both modes). Individual differences between syringe surface and ambient temperature ranged from 0.3 to 1.9 degrees C for battery operation and from 0.5 to 11.2 degrees C during main-power operation. CONCLUSION: Infusion solutions can be significantly warmed by syringe pumps. This has potential impact on bacterial growth and the stability of drug solutions and blood products infused, as well as on the susceptibility to hydrostatic pressure changes within the infusion syringe.

Infusion pump performance with vertical displacement: effect of syringe pump and assembly type.

OBJECTIVE: To evaluate the effect of different infusion pump models on continuity of drug delivery during vertical displacement of syringe pumps. DESIGN: Zero-drug delivery time (ZDDT), retrograde aspiration volume, and infusion bolus were recorded using the same syringe in three different models of syringe pump after lowering and elevating the pump. Compliance of each infusion assembly was measured using the occlusion release technique at 38 mmHg. RESULTS: Lowering the pump by 50 cm at an infusion rate of 1 ml/h resulted in ZDDT values ranging from 2.78 +/- 0.29 to 5.99 +/- 1.09 min. Elevating the syringe pump to its original position caused infusion boluses between 44.1 +/- 3.2 and 77.1 +/- 5.1 microl. The results demonstrated that there are large differences between syringe pump models (F = 66.8, df = 2/33, p < 0.0001) and between pumps of the same model (F = 21.3, df = 1/34, p < 0.0001). A similar pattern was found in retrograde aspiration volume and infusion bolus. CONCLUSION: All tested pumps led to clinically relevant flow irregularities during vertical displacement of the syringe pump. Thus, vertical displacement of any syringe pump connected to an infusion line delivering highly potent drugs at low infusion rates should be avoided. The variability across syringe pumps indicates that syringe pump design remains an area of potential further improvement for reducing the risk of adverse patient events.

Diffuse alveolar hemorrhage due to antibasement membrane antibody disease appearing with a polyglandular autoimmune syndrome.

We describe a patient with type 3-C polyglandular autoimmune syndrome who presented with diffuse alveolar hemorrhage and normal renal function. The diagnosis of antibasement membrane antibody disease was established by immunofluorescent staining of transbronchial biopsy specimens. We suggest the incorporation of antibasement membrane antibody disease into the spectrum of diseases that define the polyglandular autoimmune syndromes.

Effects of antileukemia agents on nuclear matrix-bound DNA replication in CCRF-CEM leukemia cells.

The effects of various antileukemic agents on DNA replication associated with the nuclear matrix were investigated in CCRF-CEM leukemia cells. Residual nuclear matrices were prepared by sequential treatment of nuclei with 1.5 M NaCl, DNase I, and Triton X-100 and contained 1-5, 10, and 37% of the total nuclear DNA, protein, and phospholipid, respectively. In control cells pulse-labeled for 45 s with [3H]thymidine, the specific activity of nascent DNA was four-fold greater in the nuclear matrix fraction relative to the specific activity of the high salt-soluble (nonmatrix) DNA fraction. Pulse-labeling and reconstitution experiments indicated that this enrichment of newly replicated DNA on the nuclear matrix did not result from aggregation of nascent DNA with the matrix. A 2-h incubation of tumor cells with either 0.1 microM teniposide (VM-26), 0.2 microM VM-26, or 0.5 microM amsacrine (m-AMSA) reduced the relative specific activity of nascent DNA on the nuclear matrix by 59, 61, and 54%, respectively, compared to control cells. In contrast hydroxyurea and cytosine arabinoside, at concentrations that markedly inhibited total nuclear DNA synthesis, did not decrease the relative specific activity of newly replicated DNA on the matrix. The results provide evidence that the antiproliferative effects of the DNA topoisomerase II inhibitors, VM-26 and m-AMSA, are localized on the nuclear matrix of CCRF-CEM leukemia cells.

Demand and continuous flow intermittent mandatory ventilation systems.

A mechanical lung was used to evaluate the pressure and flow characteristics of four demand and two continuous flow intermittent mandatory ventilation (IMV) systems. The amount of negative pressure required to initiate inspiratory flow and peak expiratory resistance were measured. The inspiratory pressure required to initiate flow in the demand mode was also compared to pressures generated in the assist mode. In addition, the peak expiratory resistance was measured with four commercially available exhalation valves. Results showed that the ventilator manometer measuring internal machine pressures significantly underestimated the amount of negative pressure required to open the demand valve (p less than 0.01). There are major differences in the flow and pressure characteristics among demand and continuous flow IMV systems. Systems that impose high inspiratory elastic threshold loads and expiratory flow resistive loads may have a deleterious effect on the mechanics of breathing, and thereby limit weaning success and eventually impair the recovery of certain patients in respiratory failure. The basic methodology, especially the simple technique of inserting an aneroid manometer in line next to a patient's ET tube, for measuring proximal negative inspiratory force (NIF test) can be easily applied to any and all ventilators at any practitioner's individual institution.

Oral theophylline intoxication. A serious error of patient and physician understanding.

Twenty-two episodes of hospitalization for patients with inadvertent oral theophylline intoxication were reviewed to determine the mechanism of toxicity as well as clinical features and pharmacokinetic values. Toxic effects occurred in older subjects with poorly reversible airflow obstruction and evidence of reduced theophylline clearance. Maximum serum theophylline levels ranged from 22.4 to 104.8 mg/L. Gastrointestinal tract disturbances were the most common toxic effects; three patients had grand mal seizures. Serum theophylline levels were a poor predictor of serious toxic effects. Causes of theophylline intoxication included excessive drug ingestion by the patient, excessive dose prescription by the physician, and unrecognized drug interactions. With appropriate patient selection and education, as well as better understanding of theophylline kinetics and potential drug interactions, inadvertent oral theophylline intoxication can be minimized.