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Biomedical subjects

R Gottschall

Publications and source records attributed to R Gottschall.

14 recordsLinked to original sources
PubMed2000

Catalytic methanol oxidation over copper: observation of reaction-induced nanoscale restructuring by means of in situ time-resolved X-ray absorption spectroscopy

The catalytically active copper phase for the partial oxidation of methanol is studied by means of time-resolved extended X-ray absorption fine structure (EXAFS) spectroscopy combined with the detection of the catalytic turnover. It is found that the active form of the copper is a strained nanocrystalline form of the metal. The metal is no longer made up from large crystallites but contains a defect structure in which oxygen is already intercalated.

Journal Article↗
PubMed1998

Role of fiberoptic bronchoscopy in conjunction with the use of double-lumen tubes for thoracic anesthesia: a prospective study.

BACKGROUND: Fiberoptic bronchoscopy has been recommended to verify the position of double-lumen tubes (DLT), but this remains controversial. The authors studied the role of bronchoscopy for placing and monitoring right- and left-sided DLTs after blind intubation and after positioning the patient. METHODS: Two hundred patients having thoracic surgery requiring DLT insertion were prospectively studied. "Blind" tracheal intubations were done with 163 left-sided and 37 right-sided disposable polyvinyl chloride Robertshaw tubes. Bronchoscopy was performed by a different anesthesiologist after intubation and conventional clinical verification of correct placement and after patient positioning for thoracotomy. A DLT was considered malpositioned when it had to be moved >0.5 cm to correct its position. Critical malpositions were those that might have affected patient safety or influenced the surgical procedure if left uncorrected. RESULTS: After "blind" DLT intubation, clinical evidence of malpositioning was found in 28 patients. This was confirmed by fiberoptic assessment. In 172 patients in whom placement was judged correct by clinical assessment, malpositioning was detected by bronchoscopy in 79 cases, 25 of which were critical. After patient positioning, DLTs were found to be displaced in 93 patients, 48 of which were critical. Right-sided DLTs were significantly more likely to be malpositioned than were left-sided DLTs. Two complications were related to unsatisfactory lung separation in the 200 patients studied. CONCLUSIONS: After blind intubation and patient positioning, more than one third of DLTs required repositioning. Routine bronchoscopy is therefore recommended after intubation and after patient positioning.

Adolescent↗
PubMed1998

[Value of aspiration of tracheal secretions and bronchoalveolar lavage in diagnosis of nosocomial pneumonia in ventilated patients].

The diagnostic value of endotracheal aspirates with quantitative assessment and bronchoalveolar lavage (BAL) was investigated in 104 mechanically ventilated patients in an anaesthesiologic/surgical intensive care unit. Patients were either considered as "pneumonia positive" (77 patients) according to clinical, radiological or laboratory criteria or "pneumonia negative" (27 patients). Using a threshold of 10(5) colony forming units (cfu) per ml for endotracheal aspirates and 10(4) cfu/ml for BAL-fluid, the results were similar for both techniques (sensitivity 74% and 77% respectively; specifity 63%). In our investigation, in 80% of the cases microbial growth was observed in either both or neither of the techniques. Therefore 20% of the patients had positive results in only one of the two diagnostic procedures. As a consequence of the presented study, quantitative assessment of endotracheal aspirates as a cost-effective, low-invasive and simple technique could be helpful in diagnosing nosocomial pneumonia in mechanically ventilated patients. Performance of BAL is indicated in patients with clinical signs of nosocomial pneumonia and negative results in endotracheal aspirates (< 10(5) cfu/ml). Nevertheless, diagnostic uncertainty will remain in about 15% of all cases, even when both techniques are applied. The primary use of invasive bronchoscopic techniques, such as BAL, in diagnosis of nosocomial pneumonia has to be considered critically.

Bronchoalveolar Lavage Fluid↗
PubMed1995

[Capnography for bronchoscopy with rigid technique using high frequency jet ventilation (HFJV)].

OBJECTIVES AND METHODS: Rapid bronchoscopy in general anaesthesia still has its precise indications, where the high frequency jet ventilation technique offers several advantages. The monitoring of ventilation, however, has been rather unsatisfactory up to date. We therefore studied capnography in 60 bronchoscopies during HFJV (rate: 100/min; I:E = 0.33; driving pressure: 0.08-0.14 MPa) using a rigid bronchoscope with a distally located sampling port. Continuous capnograms were recorded. End-tidal partial pressures of carbon dioxide (petCO2), however, were obtained from 2-3 single breaths by intermittently reducing the jet-frequency to 10-12/min. After 6 min (MP1: whole group; n = 60) and 18 min of HFJV (MP2: n = 34 of this group) petCO2 values were regularly obtained and compared to pCO2 in synchronously drawn capillary blood samples (pcCO2). The jet driving pressure initially adjusted to body weight, however, was only corrected according to petCO2, aiming at 34 mmHg. RESULTS: During HFJV, sinusoidal capnograms permitted the identification of every single jet impulse. With instruments being passed through the bronchoscope, however, these curves were substantially distorted. Mean pcCO2 at MP1 (37.8 +/- 6.7 mmHg) and MP2 (37.2 +/- 6.7 mmHg) demonstrated normal ventilation to light hyperventilation. Differences from mean petCO2 obtained during low frequency breathing were 3.3 mmHg at MP1 and 4.4 mmHg at MP2 (p < 0.05). There were strong correlations between the individual pairs of pcCO2 and petCO2 from MP1 (r = 0.80) and MP2 (r = 0.75) as well as between the pairs of dpcCO2 and dpetCO2 from both MPs (r = 0.77). The accuracy of the ventilator setting according to petCO2 with reference to pcCO2 was 73% for MP1 and 74% for MP2 (sensitivity: 75%/79%; specificity: 72%/67%). CONCLUSIONS: Capnography in rigid bronchoscopy during HFJV proved a clinically applicable addition to monitoring. Its routine use is strongly recommended in interventional bronchoscopy. The true petCO2 values obtained by intermittent single low frequency jet breathing permit estimates of gas exchange sufficiently exact for clinical purposes and for adjustment of the ventilator setting. Wave forms of the continuously recorded capnogram during HFJV are a warning of impeded ventilation or airway obstruction and, thus, of the danger of barotrauma or hypoventilation. Besides contributing to patient safety, this monitoring method might improve the acceptance of HFJV for bronchoscopy. Furthermore, it can also be applied to rigid bronchoscopy with common ventilation.

Adult↗
PubMed1993

[Connector for double-lumen tubes in thoracic surgery interventions].

The junction between double-lumen endotracheal tube (DLT) and anaesthetic circuit is of crucial importance to modern anaesthesiological management in thoracic surgery. We present a connector which allows for all the essential procedures, such as clinical control of DLT position, use of fiberoptic bronchoscope (FOB) to control or correct DLT position, application of differential lung ventilation patterns or simple suction manoeuvres by easy handling, minimal interference, and avoidance of disconnection or clamping.

Bronchoscopes↗
PubMed1989

[Building and performance of the Jena system for normal frequency injector (jet) ventilation in endoscopic treatments].

Experiences with three variants of use of normofrequency injector (jet)-ventilation during endoscopic procedures in laryngo-tracheobronchial area are reported. The used simple instruments and the efficiency of the method with regard to the gas exchange of the patients are described. Moreover, experimental investigations of the Kleinsasser laryngoscopic equipment at the lung model were performed. Problems of the supervision and non-endoscopic applications of the method are mentioned.

Anesthesia↗
PubMed1989

[The use of the jet ventilation technic in surgical interventions on the trachea].

Based on our own experiences and on comparisons with the literature, we demonstrated the possibilities and problems of jet ventilation technique during surgical interventions at the trachea. This method has been applied 28 times and in two cases surgical manipulations caused complications in the form of bronchial bleedings, with the occurrence of hypoventilation in one case. Due to the essentially improved prerequisites for the surgeon and optimal ventilation, the procedure of jet ventilation presents a true enrichment of the anaesthesiological repertoire, provided the indications are well established and the cooperation between surgeon and anaesthetist is good. On the other hand, however, owing to insufficiencies in the adequate monitoring if this form of ventilation, a comparably higher risk for the patient has to be taken into account.

Adult↗
PubMed1988

[Behavior of respiratory tract, esophagus and pulmonary artery pressure in bronchoscopies in normofrequent jet ventilation in comparison with Friedel's ventilation technics].

The dynamics of selected physiological respiratory parameters were studied in a total of 29 patients. During slight hyperventilation and good oxygenation by both Friedel's and jet ventilation (driving pressure 0.3 and 0.4 MPa, respectively), comparably low respiratory tract pressures were observed. Transmission to intrathoracic (44-46%) and mean pulmonary artery pressure (11-13%) indicates only a low-grade ventilation-induced hemodynamic influence. By contrast, clear increases in pulmonary artery pressure due to intubation were recorded. Thus, the employed normofrequent jet ventilation with its continuous open-tube ventilation which is independent of the undisturbed bronchological examination possesses beneficial properties from a cardiorespiratory view.

Adult↗