I was educated at the university of vienna. My scientific focus is the lung and its ventilation during respiratory insufficiency. I developed the tubusless superposed high frequency jet ventilation (SHFJV). It enables the surgeon to operate on the larynx without an endotracheal tube. I am concerned with the possible flow mechanisms in the lung, particularly under mechanical ventilation. I give a lecture at the Technical University of Vienna. The title is: Fundamentals of respiratory physiology and ventilation therapy.
Single-frequency high-frequency jet ventilation (HFJV) is an established ventilatory technique du... more Single-frequency high-frequency jet ventilation (HFJV) is an established ventilatory technique during laryngotracheal surgery. This study describes the clinical use of combined HFJV, characterised by the simultaneous application of a low-frequent (LF) and a high-frequent (HF) jet stream. Two jet streams with different pulsatile frequency (HF approx. 10 Hz, LF 10-30 bpm) and adjustable driving pressures were applied supraglottically by means of a special jet laryngoscope in patients undergoing elective laryngotracheal surgery during total intravenous anaesthesia. HFJV was performed using a pneumatic or electronic jet respirator connected to the central gas supply. 134 patients were submitted to tubeless HFJV applying the double-jet technique using the jet-laryngoscope. Duration of HFJV was < or = 30 min in 60 patients (45%), between 30 and 60 min in 49 patients (36%), and > or = 60 min in 25 patients (19%). Classification into 3 groups according to weight ((I < 65 kg, II = 6...
To evaluate right ventricular dimensions and function by echocardiography in anesthetized patient... more To evaluate right ventricular dimensions and function by echocardiography in anesthetized patients during superimposed high-frequency jet ventilation (HFJV). Prospective clinical study. University hospital operating room. 20 ASA physical status I patients undergoing elective minor otorhinolaryngological surgery, and undergoing conventional mechanical ventilation with subsequent superimposed HFJV. Two-dimensional transesophageal echocardiography with a 5-MHz multiplane transducer to determine right ventricular dimensions and function from a mid-esophageal view. Insertion of a radial artery catheter for monitoring blood pressure and blood gases. Heart rate, mean arterial blood pressure, and right ventricular end-diastolic and end-systolic volumes determined by echocardiography, stroke volume, and ejection fraction. Measurements were performed after 10 minutes of conventional positive pressure ventilation (control) and after 10 minutes of subsequent superimposed HFJV at similar peak an...
Surgery by three-dimensional (3D) endoscopy is being used routinely in abdominal surgery and, in ... more Surgery by three-dimensional (3D) endoscopy is being used routinely in abdominal surgery and, in special cases, in thoracic surgery; however, it has not been reported as being used in microlaryngeal surgery. METHODS. We inserted a 3-D endoscope into a jet laryngoscope and studied the pressure properties at the tip of the laryngoscope as well as intrapulmonary pressures while applying superimposed high-frequency jet ventilation. The studies were conducted initially using a lung simulator, and then in seven patients undergoing microlaryngeal surgery. RESULTS. Due to the rather large 3-D endoscope, the diameter of the jet laryngoscope was reduced by between 25.2% and 70.9%, depending on its size. The measurements on the lung simulator revealed that reduction of laryngoscope diameter leads to an increase in the following parameters: expiratory resistance, tidal volume, and peak inspiratory pressure. The mean FiO2 was 0.74 +/- 0.1; the mean paO2 was 169.2 +/- 80.4 mmHg; and the mean paCO...
High-frequency ventilation techniques have been applied for a number of years for laryngeal surge... more High-frequency ventilation techniques have been applied for a number of years for laryngeal surgery in order to ventilate patients without endotracheal tubes or catheters. A further development of high-frequency jet ventilation (HFJV) is the technique of superimposed HFJV (SHFJV), which was achieved by combining low- and high-frequency jet streams. Although good clinical results were observed, which have been published in the past, the clinical details of development of SHFJV have not been previously published. METHODS. In order to understand and study the mechanism of superimposition of a high-frequency jet stream, extensive experiments on a lung simulator at defined measuring points, which represented the operating field in microlaryngeal surgery and the trachea, were conducted prior to the clinical application of SHFJV. RESULTS. The measurements demonstrated that superposition of the two jet streams led to greater velocity during inspiration, and therefore produced an increase in...
Zusammenfassung. Operationen in 3-D-Technik werden in der Abdominalchirurgie und in der Thoraxc... more Zusammenfassung. Operationen in 3-D-Technik werden in der Abdominalchirurgie und in der Thoraxchirurgie bereits in Einzelfällen eingesetzt, in der mikrolaryngealen Chirurgie bislang aber noch nicht verwendet. Ein 3-D-Endoskop wurde durch das Jet-Laryngoskop eingeführt, und unter Beatmung mittels der superponierten Hochfrequenz-Jet-Ventilation (SHFJV) wurde das Druckverhalten an der Rohrspitze und intrapulmonal zunächst experimentell registriert und anschließend diese Technik klinisch bei 7 Patienten angewendet. Messungen am Lungensimulatur zeigten, daß es durch Einengung des Querschnitts des Jet-Laryngoskops zu einer Zunahme des exspiratorischen Widerstands und zu einer Zunahme des Tidalvolumens und des Beatmungsspitzendrucks kommt. Durch Reduktion des Arbeitsdrucks können der Ausgangsdruck und das ursprünglich eingestellte Tidalvolumen exakt beibehalten werden. In der klinischen Anwendung waren Beatmung, Inspektion und Operation durch das Jet-Laryngoskop bei allen Patienten problemlos möglich, der CO2-Laser konnte ohne Änderung des Beatmungsregimes eingesetzt werden. Obwohl für den Routineeinsatz im HNO-Bereich spezielle technische Veränderungen angestrebt werden müssen, konnte das 3-D-Endoskop in der vorliegenden Form in Verbindung mit der SHFJV bereits klinisch erprobt werden und bietet dem Operateur neue Möglichkeiten in der stimmverbessernden Larynxmikrochirurgie. Mittels SHFJV ist eine sichere Beatmung des Patienten möglich.
The study aimed to evaluate whether superimposed high-frequency jet ventilation (SHFJV) is a usef... more The study aimed to evaluate whether superimposed high-frequency jet ventilation (SHFJV) is a useful tool in intensive care medicine to ventilate patients with pulmonary insufficiency. Methods. SHFJV is the simultaneous application of low-and high-frequency jet ventilation ...
Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with ... more Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with decreased cerebral perfusion present a special problem on developing respiratory insufficiency, since kinetic therapy or extracorporal life support are contraindicated. Superimposed High Frequency Jet Ventilation (SHFJV) has been shown to be of benefit in ventilating patients with pulmonary insufficiency. The aim of this study was to evaluate if SHFJV could be safely applied in patients with critical cerebral blood flow; if so, SHFJV might be beneficial when pulmonary insufficiency occurs concomitantly. The study was performed in 14 patients (3 with pulmonary insufficiency) applying first moderate hyperventilation (paCO2 31 to 36 mmHg) followed by increased hyperventilation (paCO2 27 to 30 mmHg) with CMV and SHFJV and measuring intracranial pressure (ICP), cerebral perfusion pressure (CPP) and blood flow velocity (BFV) of the middle cerebral artery. BFV of the middle cerebral artery whic...
Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with ... more Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with decreased cerebral perfusion present a special problem on developing respiratory insufficiency, since kinetic therapy or extracorporal life support are contraindicated. Superimposed High Frequency Jet Ventilation (SHFJV) has been shown to be of benefit in ventilating patients with pulmonary insufficiency. The aim of this study was to evaluate if SHFJV could be safely applied in patients with critical cerebral blood flow; if so, SHFJV might be beneficial when pulmonary insufficiency occurs concomitantly. The study was performed in 14 patients (3 with pulmonary insufficiency) applying first moderate hyperventilation (paCO2 31 to 36 mmHg) followed by increased hyperventilation (paCO2 27 to 30 mmHg) with CMV and SHFJV and measuring intracranial pressure (ICP), cerebral perfusion pressure (CPP) and blood flow velocity (BFV) of the middle cerebral artery. BFV of the middle cerebral artery whic...
Single-frequency high-frequency jet ventilation (HFJV) is an established ventilatory technique du... more Single-frequency high-frequency jet ventilation (HFJV) is an established ventilatory technique during laryngotracheal surgery. This study describes the clinical use of combined HFJV, characterised by the simultaneous application of a low-frequent (LF) and a high-frequent (HF) jet stream. Two jet streams with different pulsatile frequency (HF approx. 10 Hz, LF 10-30 bpm) and adjustable driving pressures were applied supraglottically by means of a special jet laryngoscope in patients undergoing elective laryngotracheal surgery during total intravenous anaesthesia. HFJV was performed using a pneumatic or electronic jet respirator connected to the central gas supply. 134 patients were submitted to tubeless HFJV applying the double-jet technique using the jet-laryngoscope. Duration of HFJV was < or = 30 min in 60 patients (45%), between 30 and 60 min in 49 patients (36%), and > or = 60 min in 25 patients (19%). Classification into 3 groups according to weight ((I < 65 kg, II = 6...
To evaluate right ventricular dimensions and function by echocardiography in anesthetized patient... more To evaluate right ventricular dimensions and function by echocardiography in anesthetized patients during superimposed high-frequency jet ventilation (HFJV). Prospective clinical study. University hospital operating room. 20 ASA physical status I patients undergoing elective minor otorhinolaryngological surgery, and undergoing conventional mechanical ventilation with subsequent superimposed HFJV. Two-dimensional transesophageal echocardiography with a 5-MHz multiplane transducer to determine right ventricular dimensions and function from a mid-esophageal view. Insertion of a radial artery catheter for monitoring blood pressure and blood gases. Heart rate, mean arterial blood pressure, and right ventricular end-diastolic and end-systolic volumes determined by echocardiography, stroke volume, and ejection fraction. Measurements were performed after 10 minutes of conventional positive pressure ventilation (control) and after 10 minutes of subsequent superimposed HFJV at similar peak an...
Surgery by three-dimensional (3D) endoscopy is being used routinely in abdominal surgery and, in ... more Surgery by three-dimensional (3D) endoscopy is being used routinely in abdominal surgery and, in special cases, in thoracic surgery; however, it has not been reported as being used in microlaryngeal surgery. METHODS. We inserted a 3-D endoscope into a jet laryngoscope and studied the pressure properties at the tip of the laryngoscope as well as intrapulmonary pressures while applying superimposed high-frequency jet ventilation. The studies were conducted initially using a lung simulator, and then in seven patients undergoing microlaryngeal surgery. RESULTS. Due to the rather large 3-D endoscope, the diameter of the jet laryngoscope was reduced by between 25.2% and 70.9%, depending on its size. The measurements on the lung simulator revealed that reduction of laryngoscope diameter leads to an increase in the following parameters: expiratory resistance, tidal volume, and peak inspiratory pressure. The mean FiO2 was 0.74 +/- 0.1; the mean paO2 was 169.2 +/- 80.4 mmHg; and the mean paCO...
High-frequency ventilation techniques have been applied for a number of years for laryngeal surge... more High-frequency ventilation techniques have been applied for a number of years for laryngeal surgery in order to ventilate patients without endotracheal tubes or catheters. A further development of high-frequency jet ventilation (HFJV) is the technique of superimposed HFJV (SHFJV), which was achieved by combining low- and high-frequency jet streams. Although good clinical results were observed, which have been published in the past, the clinical details of development of SHFJV have not been previously published. METHODS. In order to understand and study the mechanism of superimposition of a high-frequency jet stream, extensive experiments on a lung simulator at defined measuring points, which represented the operating field in microlaryngeal surgery and the trachea, were conducted prior to the clinical application of SHFJV. RESULTS. The measurements demonstrated that superposition of the two jet streams led to greater velocity during inspiration, and therefore produced an increase in...
Zusammenfassung. Operationen in 3-D-Technik werden in der Abdominalchirurgie und in der Thoraxc... more Zusammenfassung. Operationen in 3-D-Technik werden in der Abdominalchirurgie und in der Thoraxchirurgie bereits in Einzelfällen eingesetzt, in der mikrolaryngealen Chirurgie bislang aber noch nicht verwendet. Ein 3-D-Endoskop wurde durch das Jet-Laryngoskop eingeführt, und unter Beatmung mittels der superponierten Hochfrequenz-Jet-Ventilation (SHFJV) wurde das Druckverhalten an der Rohrspitze und intrapulmonal zunächst experimentell registriert und anschließend diese Technik klinisch bei 7 Patienten angewendet. Messungen am Lungensimulatur zeigten, daß es durch Einengung des Querschnitts des Jet-Laryngoskops zu einer Zunahme des exspiratorischen Widerstands und zu einer Zunahme des Tidalvolumens und des Beatmungsspitzendrucks kommt. Durch Reduktion des Arbeitsdrucks können der Ausgangsdruck und das ursprünglich eingestellte Tidalvolumen exakt beibehalten werden. In der klinischen Anwendung waren Beatmung, Inspektion und Operation durch das Jet-Laryngoskop bei allen Patienten problemlos möglich, der CO2-Laser konnte ohne Änderung des Beatmungsregimes eingesetzt werden. Obwohl für den Routineeinsatz im HNO-Bereich spezielle technische Veränderungen angestrebt werden müssen, konnte das 3-D-Endoskop in der vorliegenden Form in Verbindung mit der SHFJV bereits klinisch erprobt werden und bietet dem Operateur neue Möglichkeiten in der stimmverbessernden Larynxmikrochirurgie. Mittels SHFJV ist eine sichere Beatmung des Patienten möglich.
The study aimed to evaluate whether superimposed high-frequency jet ventilation (SHFJV) is a usef... more The study aimed to evaluate whether superimposed high-frequency jet ventilation (SHFJV) is a useful tool in intensive care medicine to ventilate patients with pulmonary insufficiency. Methods. SHFJV is the simultaneous application of low-and high-frequency jet ventilation ...
Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with ... more Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with decreased cerebral perfusion present a special problem on developing respiratory insufficiency, since kinetic therapy or extracorporal life support are contraindicated. Superimposed High Frequency Jet Ventilation (SHFJV) has been shown to be of benefit in ventilating patients with pulmonary insufficiency. The aim of this study was to evaluate if SHFJV could be safely applied in patients with critical cerebral blood flow; if so, SHFJV might be beneficial when pulmonary insufficiency occurs concomitantly. The study was performed in 14 patients (3 with pulmonary insufficiency) applying first moderate hyperventilation (paCO2 31 to 36 mmHg) followed by increased hyperventilation (paCO2 27 to 30 mmHg) with CMV and SHFJV and measuring intracranial pressure (ICP), cerebral perfusion pressure (CPP) and blood flow velocity (BFV) of the middle cerebral artery. BFV of the middle cerebral artery whic...
Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with ... more Patients with increased intracranial pressure or vasospasm after subarachnoidal haemorrhage with decreased cerebral perfusion present a special problem on developing respiratory insufficiency, since kinetic therapy or extracorporal life support are contraindicated. Superimposed High Frequency Jet Ventilation (SHFJV) has been shown to be of benefit in ventilating patients with pulmonary insufficiency. The aim of this study was to evaluate if SHFJV could be safely applied in patients with critical cerebral blood flow; if so, SHFJV might be beneficial when pulmonary insufficiency occurs concomitantly. The study was performed in 14 patients (3 with pulmonary insufficiency) applying first moderate hyperventilation (paCO2 31 to 36 mmHg) followed by increased hyperventilation (paCO2 27 to 30 mmHg) with CMV and SHFJV and measuring intracranial pressure (ICP), cerebral perfusion pressure (CPP) and blood flow velocity (BFV) of the middle cerebral artery. BFV of the middle cerebral artery whic...
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