Astrid Chiari - Academia.edu (original) (raw)

Papers by Astrid Chiari

Gynäkologisch-geburtshilfliche Rundschau, 1995

Regional Anesthesia & Pain Medicine, 1996

Ophthalmologica, 1992

ABSTRACT

Journal of Computer Assisted Tomography, 1999

Our goal was to demonstrate the feasibility of an in vivo noninvasive method for imaging spinal c... more Our goal was to demonstrate the feasibility of an in vivo noninvasive method for imaging spinal cord cholinergic terminals using (+)-4-[18F]fluorobenzyltrozamicol ([18F]FBT) and PET. In vitro and in vivo experiments in rats were conducted to demonstrate the specific binding characteristics, localization, and time course of [3H]FBT binding in the spinal cord. PET imaging was then performed on seven rhesus monkeys. The rat studies demonstrate high specific binding in the spinal cord with a distribution coinciding with the known distribution of cholinergic terminals. In vivo tracer concentrations in the spinal cord and basal ganglia were of the same magnitude. With use of [18F]FBT and PET in the rhesus monkey, the spinal cord was clearly visualized, with tracer concentration in the spinal cord being approximately one-fourth of that seen in the basal ganglia. This work demonstrates the feasibility of imaging cholinergic terminals in vivo in the spinal cord using [18F]FBT and PET.

Blood Coagulation & Fibrinolysis, 2010

Drug monitoring of low molecular weight heparin is generally not recommended, but could be reason... more Drug monitoring of low molecular weight heparin is generally not recommended, but could be reasonable in critically ill patients, whose risk for bleeding or thrombosis shows a high interpatient variability. Anti-Xa assays are not available around the clock even in central hospitals, whereas rotational thrombelastometry (ROTEM) becomes increasingly used at the bedside. Prothrombinase-induced clotting time (PiCT) reagent allows determination of factor Xa-inhibition in plasma. The aim of our study was to evaluate enoxaparin determination in whole blood with the ROTEM using specific test modifications, including PiCT. After ethics committee's approval, citrated whole blood obtained from overall 16 healthy volunteers was incubated with enoxaparin at 16 different anti-Xa concentrations. Main endpoint was the clotting time (CT) in ROTEM representing initial activation of clot formation. CT was determined in the new PiCT-ROTEM test, in a low-tissue factor-activated modification (LowTF-ROTEM) as well as in the commercially available heparin-sensitive ROTEM assays (HEPTEM and INTEM). In the absence of enoxaparin, CT values were 168.6 W 6.1 s (PiCT-ROTEM), 247.3 W 18.6 s (LowTF-ROTEM), and-6.2 W 7.9 s (INTEM-HEPTEM). A linear dependency (P < 0.01) between anti-Xa concentration and CT was found for PiCT-ROTEM, LowTF-ROTEM, and for INTEM-HEPTEM with correlation coefficients of 0.93 for PiCT-ROTEM, 0.94 for LowTF-ROTEM, and 0.81 for INTEM-HEPTEM. This in-vitro experiment demonstrates a strong correlation between enoxaparin anti-Xa concentrations and specific ROTEM tests. These promising assays should be further evaluated for monitoring anticoagulation in high-risk patients in clinical studies.

Anaesthesia, 1995

Haemodynamic and hormonal responses to tracheal intubation can be profound and associated with se... more Haemodynamic and hormonal responses to tracheal intubation can be profound and associated with serious cardiovascular and cerebral side eflects. The Augustine Guide, a device enabling blind oral intubation, has been introduced recently. The aim of our study was to compare the haemodynamic and hormonal stress response of this method with direct laryngoscopy. Thirty jive patients (ASA 1 and 2) were randomly assigned to undergo either direct laryngoscopy (n = I7), or blind oral intubation (n = 18). Haemodynamic responses and concentrations of adrenaline, noradrenaline and prolactin were determined prior to induction, before intubation and Smin after intubation. The median duration of intubation was 22s for direct laryngoscopy us 46s for blind oral intubation @ < 0.05). Between the groups, no signijicant dixerences were observed for heart rate, systolic or mean arterial blood pressure. Serum levels of adrenaline decreased slightly after induction and remained unaltered after intubation in both groups. Noradrenaline (1.01 us 0.66nmoI.l-') and prolactin (5.2 us 2.9nmol.l-') levels were signijicantly higher after direct laryngoscopy compared to blind oral intubation. Although blind oral intubation took signijican fly longer to perform than direct laryngoscopy, hormonal stress response was less pronounced. Blind oral intubation should therefore not be withheld from patients with impaired cardiovascular reserve.

BMC Neurology, Dec 22, 2022

Background: The efficacy of recanalization treatment in patients with ischemic stroke due to larg... more Background: The efficacy of recanalization treatment in patients with ischemic stroke due to large vessel occlusion (LVO) is highly time dependent. We aimed to investigate the effects of an optimization of prehospital and intrahospital pathways on time metrics and efficacy of endovascular treatment in ischemic stroke due to LVO. Methods: Patients treated with mechanical thrombectomy (MT) at the Hospital of St. John of God Vienna, Austria, between 2013 and 2020 were extracted from the Austrian Stroke Unit Registry. Study endpoints including time metrics, early neurological improvement and functional outcome measured by modified Rankin Scale (mRS) at 3 months were compared before and after optimization of prehospital and intrahospital pathways. Results: Two hundred ninety-nine patients were treated with MT during the study period, 94 before and 205 after the workflow optimization. Workflow optimization was significantly associated with time metrics improvement (door to groin puncture time 45 versus 31 min; p < 0.001), rates of neurological improvement (NIHSS ≥ 8: 30 (35%) vs. 70 (47%), p = 0.04) and radiological outcome (TICI ≥ 2b: 71 (75%) versus 153 (87%); p = 0.013). Functional outcome (mRS 0-2: 17 (18%) versus 57 (28%); p = 0.067) and mortality (34 (37%) versus 54 (32%); p = 0.450) at 3 months showed a non-significant trend in the later time period group. Conclusion: The implementation of workflow optimization was associated a significant reduction of intrahospital time delays and improvement of neurological and radiological outcomes.

Journal of Clinical Anesthesia, 2017

Study objective: Several factors such as lack of unidirectional, turbulent free laminar airflow, ... more Study objective: Several factors such as lack of unidirectional, turbulent free laminar airflow, duration of surgery, patient warming system, or the number of health professionals in the OR have been shown or suspected to increase the number of airborne bacteria. The objective of this study was to perform a multivariate analysis of bacterial counts in the OR in patients during minor orthopedic surgery. Design: Prospective, randomized pilot study.

Acta anaesthesiologica Scandinavica. Supplementum

Regional Anesthesia and Pain Medicine, 2006

The Journal of pharmacology and experimental therapeutics, 2000

Nitric oxide has been shown to react under physiologic conditions with norepinephrine (NE) to pro... more Nitric oxide has been shown to react under physiologic conditions with norepinephrine (NE) to produce 6-nitro-norepinephrine (6-NO(2)-NE), a compound that enhances NE release in the brain. Previous studies suggest that 6-NO(2)-NE is formed in the spinal cord and stimulates spinal NE release to produce analgesia. The purpose of the current studies was to examine the mechanisms by which 6-NO(2)-NE stimulates NE release in the spinal cord. Crude synaptosomes were prepared from spinal cords of male Sprague-Dawley rats and loaded with [(3)H]NE. Incubation of synaptosomes with 6-NO(2)-NE resulted in a release of NE, with a threshold of 1 microM 6-NO(2)-NE and a maximum effect of 30% fractional release. NE transporter inhibitors desipramine and nomifensine blocked NE release from 6-NO(2)-NE, and desipramine exhibited an IC(50) of 9.6 microM. NE release from 6-NO(2)-NE was dependent on external Na(+), but not Ca(2+) or the activity of guanylate cyclase. 6-NO(2)-NE also blocked uptake of [(3...

The International Journal of Artificial Organs, 2014

Purpose Veno-venous extracorporeal membrane oxygenation (vv-ECMO) is pivotal in the treatment of ... more Purpose Veno-venous extracorporeal membrane oxygenation (vv-ECMO) is pivotal in the treatment of patients suffering from acute respiratory distress syndrome (ARDS). Comparative data with different oxygenator models have not yet been reported. The aim of this retrospective investigation was therefore to assess whether different oxygenator types might influence changing frequency, infection incidence, and mortality in patients on vv-ECMO. Methods 42 patients undergoing vv-ECMO between 1998 and 2009 were identified. In 20 out of these patients, a polypropylene (PP) microporous hollow fiber membrane oxygenator, and in 22 patients a nonmicroporous polymethylpentene (PMP) diffusion membrane oxygenator was used. Infection incidence, changing frequency, and mortality were documented. Results In the PMP group, an oxygenator change was necessary less often than in the PP group (p<0.001). The incidence of bacterial, viral, or fungal growth was similar in the groups, thus independent of the ...

Verbrennungen, 2009

Die intensivmedizinische Behandlung Brandverletzter setzt eine sehr hohe Spezialisierung sowohl v... more Die intensivmedizinische Behandlung Brandverletzter setzt eine sehr hohe Spezialisierung sowohl von chirurgischer als auch von intensivmedizinischer Seite voraus. Aus diesem Grund werden in den Guidelines der European Burns Association (EBA) unter anderem die Behandlung von mindestens 75 Brandverletzten pro Jahr und Zentrum gefordert. Im Folgenden sollen die Besonderheiten in der Behandlung Brandverletzter zusammengefasst werden, wobei jede einzelne Besonderheit für sich

Resuscitation, 2011

Background: The SimBaby high-fidelity patient simulator is a widely used paediatric simulator for... more Background: The SimBaby high-fidelity patient simulator is a widely used paediatric simulator for the training of standard and critical airway management scenarios. Furthermore this simulator is frequently used for the evaluation of different airway devices and techniques. However, the anatomic structures of the SimBaby have not been compared to actual patients' anatomy. Methods: The CT radiographic measures of the upper airway anatomy of two SimBaby simulators were compared to MRI images of the upper airway of 20 children aged 1-11 months who underwent routine MRI scans under sedation for diagnostic purposes. Various distances of the tongue, soft palate and pharynx, cross sectional areas and volumes of anatomic structures of the upper airway including the retroglossal airspace were compared. Results: The SimBaby's retroglossal airspace volume greatly differed from the measurements in patients (SimBaby 5.3 ± 0.4 vs. 1.9 ± 0.8 cm 3 in infants, p < 0.01). Furthermore the distance from the alveolar process of the mandible to the posterior pharyngeal wall was larger in the SimBaby than in infants (5.8 ± 0.1 vs. 4.5 ± 0.5 cm, p < 0.001) and dimensions of the epiglottis and pharynx were larger in the Simbaby. Conclusion: The anatomic features of the SimBaby do not adequately simulate the upper airway anatomy of infants. These results imply inadequate realism of this simulator for airway training and compromise the validity of comparative trials of different airway devices with the SimBaby as airway model.

Regional Anesthesia and Pain Medicine, 2008

Continuous spinal anesthesia via a spinal catheter allows adjusting the duration and extent of an... more Continuous spinal anesthesia via a spinal catheter allows adjusting the duration and extent of anesthesia to surgical needs, maintenance of hemodynamic stability, and good postoperative analgesia. This study was designed to determine the median effective local anesthetic dose of plain ropivacaine and bupivacaine administered intrathecally for interstitial brachytherapy of the lower abdomen using the Dixon up-and-down method. Forty patients were randomly allocated to receive either intrathecal bupivacaine 5 mg per mL or ropivacaine 10 mg per mL via a 24-gauge spinal catheter at the L3-4 interspace. The initial dose was 10 mg of bupivacaine or 20 mg of ropivacaine; the dosing intervals were 1 mg and 2 mg, respectively. Doses for subsequent patients were determined by the response of the previous patient in that group. Successful anesthesia was defined as a loss of sensation to a cold stimulus at the T6 level and full motor blockade within 20 minutes after administration of the local anesthetic. The median effective local anesthetic dose for intrathecal bupivacaine was 11.2 mg (95% confidence interval [CI], 10.3-12.1) and 22.6 mg for ropivacaine (95% CI, 20.5-24.6). A relative analgesic potency ratio of 0.50 (95% CI, 0.44-0.56) was calculated between the median effective local anesthetic dose of intrathecal bupivacaine and ropivacaine. Bupivacaine and ropivacaine are appropriate for continuous spinal anesthesia for interstitial radiation therapy procedures of the lower abdomen. In the dose-ranges investigated, intrathecal ropivacaine is approximately half as potent as bupivacaine.

Pain, 2001

Positron emission tomography (PET) imaging of spinal cord in monkeys with a cholinergic tracer de... more Positron emission tomography (PET) imaging of spinal cord in monkeys with a cholinergic tracer demonstrates increased spinal cholinergic activity in response to an analgesic dose of morphine, and this PET result correlates with measurement of acetylcholine spillover into spinal cord extracellular space induced by morphine, as measured by microdialysis. Previous studies in rats, mice, and sheep demonstrate activation of spinal cholinergic neurons by systemic opioid administration, and participation of this cholinergic activity in opioid-induced analgesia. Testing the relevance of this observation in humans has been limited to measurement of acetylcholine spillover into lumbar cerebrospinal¯uid. The purpose of this study was to apply a recently developed method to image spinal cholinergic terminals non-invasively via PET and to test the hypothesis that the tracer utilized would re¯ect changes in local cholinergic activity. Following Animal Care and Use Committee approval, seven adult male rhesus monkeys were anesthetized on three separate occasions. On two of the occasions PET scans were performed using [ 18 F] (1)-4-¯uorobenzyltrozamicol ([ 18 F]FBT), which selectively binds to the vesicular acetylcholine (ACh) transporter in the presynaptic cholinergic terminals. PET scans were preceded by injection of either saline or an analgesic dose of IV morphine (10 mg/kg). On the third occasion, microdialysis catheters were inserted in the spinal cord dorsal horn and acetylcholine concentrations in dialysates determined before and after IV morphine injection. Morphine increased cholinergic activity in the spinal cord, as determined by blood¯ow corrected distribution volume of [ 18 F]FBT in the cervical cord compared to the cerebellum. Morphine also increased acetylcholine concentrations in microdialysates from the cervical cord dorsal horn. The one animal which did not show increased spinal cholinergic activity by PET from this dose of morphine also did not show increased acetylcholine from this morphine dose in the microdialysis experiment. These data con®rm the ability to use PET to image spinal cholinergic terminals in the monkey spinal cord and suggest that acute changes in cholinergic activity can be imaged with this non-invasive technique. Following preclinical screening, PET scanning with [ 18 F]FBT may be useful to investigate mechanisms of analgesic action in normal humans and in those with pain.

Journal of Psychopharmacology, 2009

Preoperative anxiety can increase postoperative pain and is therefore important to avoid. Differe... more Preoperative anxiety can increase postoperative pain and is therefore important to avoid. Different approaches have already been tested for preoperative anxiolysis. Gabapentinoids might be a useful alternative to benzodiazepines. Pregabalin is used for treating generalized anxiety disorders and shows a favourable pharmacokinetic profile after oral administration; however, its anxiolytic effect preoperatively in healthy outpatients is still unclear. In this randomised, double-blind, placebo-controlled trial the anxiolytic effect of pregabalin in 40 outpatients undergoing standardised general anaesthesia and postoperative pain therapy for minor orthopaedic surgery was analysed. Patients received preoperatively either 300 mg pregabalin or placebo orally. The primary outcome was anxiety before anaesthesia induction, the secondary outcome the postoperative pain, both assessed using a visual analogue scale from 0 to 100. Without any side effects pregabalin reduced preoperative anxiety com...

Canadian Journal of Anesthesia/Journal canadien d'anesthésie, 2010

Purpose To determine the effect of topically applied lidocaine on perioperative airway complicati... more Purpose To determine the effect of topically applied lidocaine on perioperative airway complications when using a laryngeal mask airway device (LMAD) in children either with or without a history of recent or ongoing upper respiratory tract infection (URI). Methods In a randomized controlled double-blind trial, 34 children with a history of recent or ongoing URI and 32 non-URI children-all of whom were younger than age ten and scheduled to undergo minor surgical procedureswere randomly assigned to either a lidocaine or a placebo group. In the lidocaine group, an LMAD was lubricated with lidocaine gel before insertion, and a clear lubricating gel was used in the placebo group. The following data were recorded after standardized anesthesia induction and airway management: postoperative complications, such as coughing, desaturation, laryngospasm, and increased oral secretions, as well as length of stay in the postanesthetic recovery unit. Results Children with URI had a lower overall perioperative complication rate if they received a lidocaine gel (35%) rather than placebo (94%) (P \ 0.01). Also, the incidence of postoperative coughing was less (12% vs 53%; P = 0.03). In non-URI patients, lidocaine did not significantly reduce the rate of airway complications compared with placebo (17% vs 24%, respectively). Conclusion Lubrication of the LMAD with lidocaine gel reduces the incidence of airway complications in children with an upper respiratory tract infection.

British Journal of Anaesthesia, 2009

Background. Fluid management guided by oesophageal Doppler monitor has been reported to improve p... more Background. Fluid management guided by oesophageal Doppler monitor has been reported to improve perioperative outcome. Stroke volume variation (SVV) is considered a reliable clinical predictor of fluid responsiveness. Consequently, the aim of the present trial was to evaluate the accuracy of SVV determined by arterial pulse contour (APCO) analysis, using the FloTrac TM /Vigileo TM system, to predict fluid responsiveness as measured by the oesophageal Doppler. Methods. Patients undergoing major abdominal surgery received intraoperative fluid management guided by oesophageal Doppler monitoring. Fluid boluses of 250 ml each were administered in case of a decrease in corrected flow time (FTc) to ,350 ms. Patients were connected to a monitoring device, obtaining SVV by APCO. Haemodynamic variables were recorded before and after fluid bolus application. Fluid responsiveness was defined as an increase in stroke volume index .10%. The ability of SVV to predict fluid responsiveness was assessed by calculation of the area under the receiver operating characteristic (ROC) curve. Results. Twenty patients received 67 fluid boluses. Fifty-two of the 67 fluid boluses administered resulted in fluid responsiveness. SVV achieved an area under the ROC curve of 0.512 [confidence interval (CI) 0.32-0.70]. A cutoff point for fluid responsiveness was found for SVV 8.5% (sensitivity: 77%; specificity: 43%; positive predictive value: 84%; and negative predictive value: 33%). Conclusions. This prospective, interventional observer-blinded study demonstrates that SVV obtained by APCO, using the FloTrac TM /Vigileo TM system, is not a reliable predictor of fluid responsiveness in the setting of major abdominal surgery.