Endobronchial donor pre-treatment with ventavis: is a second administration during reperfusion beneficial to optimize post-ischemic function of non-heart beating donor lungs?

BACKGROUND: Lung retrieval from non-heart-beating donors (NHBD) has been introduced into clinical practice successfully. However, because of potentially deleterious effects of warm ischemia on microvascular integrity, use of NHBD lungs is limited by short tolerable time periods before preservation. Recently, improvement of NHBD graft function was demonstrated by donor pre-treatment using aerosolized Ventavis (Schering Inc., Berlin, Germany). Currently, there is no information whether additional application of this approach in reperfusion can further optimize immediate graft function. MATERIAL AND METHODS: Asystolic pigs (n = 5/group) were ventilated for 180-min of warm ischemia (groups 1-3). In groups 2 and 3, 100 microg Ventavis were aerosolized over 30-min using an ultrasonic nebulizer (Optineb). Lungs were then retrogradely preserved with Perfadex and stored for 3-h. After left lung transplantation and contralateral lung exclusion, grafts were reperfused for 6-h. Only in group 3, another dose of 100 microg Ventavis was aerosolized during the first 30-min of reperfusion. Hemodynamics, pO2/FiO2 and dynamic compliance were monitored continuously and compared to controls. Intraalveolar edema was quantified stereologically, and extravascular-lung-water-index (EVLWI) was measured. Statistics comprised ANOVA analysis with repeated measurements. RESULTS: Dynamic compliance was significantly lower in both Ventavis groups, but additional administration did not result in further improvement. Oxygenation, pulmonary hemodynamics, EVLWI and intraalveolar edema formation were comparable between groups. CONCLUSIONS: Alveolar deposition of Ventavis in NHBD lungs before preservation significantly improves dynamic lung compliance and represents an important strategy for improvement of preservation quality and expansion of warm ischemic intervals. However, additional application of this method in early reperfusion is of no benefit.

Mechanical thrombectomy for acute ischemic stroke: thrombus-device interaction, efficiency, and complications in vivo

BACKGROUND AND PURPOSE: Mechanical thrombectomy is a promising new modality of interventional stroke treatment. The various devices differ with regard to where they apply force on the thrombus, taking a proximal approach such as aspiration devices or a distal approach such as basket-like devices. The study compares the in vivo effectiveness and thrombus-device interaction of these 2 approaches. METHODS: Angiography and embolization with a radioopaque whole blood thrombus was performed in 10 swine. Mechanical thrombectomy was performed in 20 cranial vessels using a proximal aspiration device (Vasco35) and a distal basket-like device (Catch) with and without proximal balloon occlusion. Fifty-six retrieval attempts were made. RESULTS: The proximal device allowed fast repeated application with a low risk of thromboembolic events (3%) and vasospasm, but it had a significantly lower success rate (39.4%) in retrieving thrombotic material than the distal device (DD) (82.6%; odds ratio, 7.3; 95% CI, 2.0 to 26.4). The compaction of the thrombus during retrieval with DD increased the risk of vessel wall irritation significantly (P<0.01) and complicated retrieval into the guiding catheter. The number of embolic events was significantly higher with DD (26%; odds ratio, 11.3; 95% CI, 1.35 to 101.6) unless proximal balloon occlusion was used. CONCLUSIONS: The proximal and the distal approaches to mechanical thrombectomy proved to be effective at achieving recanalization of cranial vessels. The proximal device is faster in application and allowed repeated attempts with a low complication rate. The DD is more successful at removing thrombotic material, but its method of application and attendant thrombus compaction increase the risk of thromboembolic events and vasospasms.

Time to admission in acute ischemic stroke and transient ischemic attack

BACKGROUND AND PURPOSE: The effect of thrombolysis depends on the time from stroke onset to treatment and therefore also on the time when patients come to the hospital. This study was designed to analyze the variables that influence the time from symptom onset to admission (TTA) to the stroke unit. METHODS: We evaluated the medical records of 615 consecutive stroke or transient ischemic attack (TIA) patients admitted to our neurological department within 48 hours after symptom onset. RESULTS: The median TTA was 180 minutes. Referral by emergency medical services (EMS; P<0.001), high National Institutes of Health Stroke Scale (NIHSS) scores (P<0.001), strokes in the carotid territory (P<0.001), and strokes not attributable to small vessel disease (P<0.001) were associated with shorter prehospital delays. The TTA was adjusted for travel times (adjTTA), and all these variables remained significantly associated with time to admission. In addition, patients with previous experience with stroke or TIA had longer adjTTA (P=0.028). Regression analysis confirmed the independent association between referral by EMS (P=0.010), high NIHSS scores (P<0.001), carotid territory stroke (P<0.001), and first-ever cerebrovascular event (P=0.022) with shorter adjTTA. CONCLUSIONS: Factors such as NIHSS scores and stroke location influence the time to admission but, unlike referral pathways, cannot be modified. Educational programs and stroke campaigns should therefore not only teach typical and less common stroke symptoms and signs but also that EMS provides the fastest means of transportation to a stroke unit and the best chances to get treatment early.

Sleep-disordered breathing and acute ischemic stroke: diagnosis, risk factors, treatment, evolution, and long-term clinical outcome

BACKGROUND AND PURPOSE: Sleep-disordered breathing (SDB) is frequent in stroke patients. Risk factors, treatment response, short-term and long-term outcome of SDB in stroke patients are poorly known. METHODS: We prospectively studied 152 patients (mean age 56+/-13 years) with acute ischemic stroke. Cardiovascular risk factors, Epworth sleepiness score (ESS), stroke severity/etiology, and time of stroke onset were assessed. The apnea-hypopnea index (AHI) was determined 3+/-2 days after stroke onset and 6 months later (subacute phase). Continuous positive airway pressure (CPAP) treatment was started acutely in patients with SDB (AHI > or =15 or AHI > or =10+ESS >10). CPAP compliance, incidence of vascular events, and stroke outcome were assessed 60+/-16 months later (chronic phase). RESULTS: Initial AHI was 18+/-16 (> or =10 in 58%, > or =30 in 17% of patients) and decreased in the subacute phase (P<0.001). Age, diabetes, and nighttime stroke onset were independent predictors of AHI (r2=0.34). In patients with AHI > or =30, age, male gender, body mass index, diabetes, hypertension, coronary heart disease, ESS, and macroangiopathic etiology of stroke were significantly higher/more common than in patients with AHI <10. Long-term incidence of vascular events and stroke outcome were similar in both groups. CPAP was started in 51% and continued chronically in 15% of SDB pts. Long-term stroke mortality was associated with initial AHI, age, hypertension, diabetes, and coronary heart disease. CONCLUSIONS: SDB is common particularly in elderly stroke male patients with diabetes, nighttime stroke onset, and macroangiopathy as cause of stroke; it improves after the acute phase, is associated with an increased poststroke mortality, and can be treated with CPAP in a small percentage of patients.

Ischemic muscle necrosis leading to life-threatening hyperkalemia. Case report and review of the literature

Objective: Description of a cat with ischemic muscle necrosis that suffered from cardiopulmonary arrest due to hyperkalemia. Pathogenesis, clinical signs and therapy of ischemic muscle necrosis are discussed and possible causes, symptoms and treatment of hyperkalemia are shown. Material and methods: case report of a four-year-old male castrated domestic shorthair cat. Results: The cat was successfully resuscitated and hyperkalemia was treated with different treatment modalities. Conclusion: Ischemic muscle necrosis can lead to severe live-threatening hyperkalemia which has to be anticipated, monitored and treated adequately. Aggressive fluid therapy might be responsible for a higher risk of hyperkalemia in predisposed cases. Clinical relevance: Potassium concentrations and acid-base disturbances must be closely monitored in patients with ischemic muscle necrosis

Microwave remote sensing of stratospheric trace gases using digital Fast Fourier Transform spectrometers

The Institute of Applied Physics observes middle atmospheric trace gases, such as ozone and water vapour, by microwave radiometry. We report on the comparison of measurements using a novel digital Fast Fourier Transform and accousto optical spectrometers. First tests made on ground are presented as well as first experience about the use of such spectrometers under aircraft conditions.

Early recurrent ischemic stroke in stroke patients undergoing intravenous thrombolysis

BACKGROUND: We assessed the incidence of early recurrent ischemic stroke in stroke patients treated with intravenous tissue-type plasminogen activator (tPA) and the temporal pattern of its occurrence compared with symptomatic intracranial hemorrhage (ICH). METHODS AND RESULTS: Prospectively collected, population-based data for 341 consecutive acute stroke patients (62% men; mean age, 66 years) treated with tPA according to the National Institute of Neurological Disorders and Stroke study protocol at 8 medical centers in Switzerland (3 academic and 5 community) between January 2001 and November 2004 were retrospectively analyzed. The primary outcome measure was neurological deterioration > or = 4 points on the National Institutes of Health Stroke Scale occurring within 24 hours of tPA treatment and caused either by recurrent ischemic stroke (defined as the occurrence of new neurological symptoms suggesting involvement of initially unaffected vascular territories and evidence of corresponding ischemic lesions on cranial computed tomography scans, in the absence of ICH) or by ICH. Early recurrent ischemic stroke was diagnosed in 2 patients (0.59%; 95% confidence interval, 0.07% to 2.10%) and symptomatic ICH in 15 patients (4.40%; 95% confidence interval, 2.48% to 7.15%). Both recurrent ischemic strokes occurred during thrombolysis, whereas symptomatic ICHs occurred 2 to 22 hours after termination of tPA infusion. CONCLUSIONS: Recurrent ischemic stroke is a rare cause of early neurological deterioration in acute stroke patients undergoing intravenous thrombolysis, with a different temporal pattern compared with that of symptomatic ICH.