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Biomedical subjects

A Aloy

Publications and source records attributed to A Aloy.

At least 37 records · Page 2Linked to original sources
PubMed1996

Application of SHFJV for surgical procedures.

Using SHFJV in combination with the jet laryngoscope it is possible to ventilate patients for laryngeal surgery with out the necessity for any kind of endotracheal tube or catheters. This technique can also safely be applied in patients with underlying pulmonary or cardiac disease or in obese patients. Patients with laryngeal stenosis can be ventilated from above the stenosis eliminating the danger of barotrauma. The laser can be used at any time the surgeon desires without any additional protective measures. The SHFJV can be used for tracheobronchial stent insertion. Only in cases were the glottis can not be visualized through the jet laryngoscope sufficient ventilation is not ensured and therefore transtracheal high frequency ventilation is the technique of choice.

Adolescent↗
PubMed1995

[Laryngeal surgery with a 3-D technique. Early results with the jet-laryngoscope in superimposed high-frequency jet ventilation].

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 paCO2 was 40.9 +/- 2.4 mmHg. The mean airway pressure was 19 +/- 5.3 mmHg prior to insertion of the endoscope and 12.3 +/- 6.9 mmHg after insertion. The mean positive end-expiratory pressure values increased from 2 +/- 0.6 to 3.6 +/- 2.3 mmHg. Reduction of the working pressure resulted in restoration of the initial inspiratory pressures and tidal volumes. CONCLUSIONS. In the clinical application of 3-D endoscopy via a jet laryngoscope, it was possible to achieve sufficient ventilation, inspection of the surgical field, and performance of the surgical procedure. A CO2 laser was used without changing the ventilation regime. Although technical alterations would be desirable for its application to microlaryngeal surgery, it is presently possible to safely use the 3-D endoscope via the jet laryngoscope for microlaryngeal surgery, presenting the surgeon with new possibilities in voice-improving microsurgery of the larynx.

Aged↗
PubMed1995

[Preliminary experiences with superimpoposed high-frequence jet ventilation in intensive care].

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 performed using a specially designed ventilator. SHFJV versus conventional mechanical ventilation (CMV) was were applied in three groups of patients. Group 1 (Gr 1) included patients without pulmonary insufficiency; group 2 (Gr 2) patients had moderate and those in group 3 (Gr 3) had severe pulmonary insufficiency. RESULTS. In Gr 1 and Gr 2, SHFJV was associated with a significant decrease in mean airway pressure (mPAW 12.9 vs. 13.3 mm Hg, P < 0.05). In Gr 3 oxygenation was significantly better with SHFJV (mean paO2 140.1 vs. 109.9 mm Hg, P < 0.05; mean FiO2 0.66 vs. 0.86, P < 0.05). Other parameters, such as maximum airway pressure (Pmax) and mean Paw, were significantly lower with SHFJV than CMV (mean Pmax 29.6 vs. 40.1 mm Hg, mean Paw 18 vs. 21.9 mm Hg, P < 0.05). Intrapulmonary shunt fractions showed a significant decrease with SHFJV (24.6 vs. 34.4, P < 0.05). CONCLUSIONS. Significant differences were observed primarily in Gr 3 patients, indicating that patients with severe pulmonary insufficiency may benefit from SHFJV. SHFJV may thus represent an alternative mode of ventilation in critically ill patients.

Adolescent↗
PubMed1995

[Flow pattern of respiratory gases in superimposed high-frequency jet ventilation (SHFJV) with the jet laryngoscope].

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 tidal volume and entrainment of inspiratory gas. This demonstrates that it is possible to apply a HFJV technique in patients even with an open system. During expiration, the velocity of the low-frequency gas stream is decreased by the opposing flow of the high-frequency jet stream, leading to the buildup of positive end-expiratory pressure. The pulsations of the high-frequency jet stream induce continuous alveolar ventilation. The positioning of the jet nozzles in the jet laryngoscopy has the result that the velocities are already decreased at the tip of the laryngoscope and decrease further with distance from the nozzles. This prevents possible damage to the laryngeal mucosa.

Air Pressure↗
PubMed1995

[Superimposed high-frequency jet ventilation (SHFJV) in the administration of NO. Technical basis and early clinical results with ARDS].

The mortality of patients with acute respiratory distress syndrome (ARDS) is still above 50% despite continuous progress in intensive care medicine. Recent therapy regimens such as the extra corporeal life support (ECLS), permissive hypercarbia, high-frequency ventilation techniques and inhaled nitric oxide (NO) are being applied. All of the above techniques are aimed at different parts of the problems caused by ARDS. This study was designed to evaluate the possible additive benefits of superimposed high-frequency jet ventilation (SHFJV) and inhaled NO. METHODS. In experiments on a lung simulator it was demonstrated that it is possible to administer exact amounts of NO using a computer-controlled system with a feedback loop (Pulmonox) using the SHFJV. Applying the therapeutic reference point of 20 ppm of NO, the deviation was +/- 3 ppm at this setting. CASE REPORT. After successfully concluding our experiments, this combined therapy concept was applied in a patient with terminal ARDS. Under CMV, paO2 was 69.4 mm Hg and the oxygen saturation 88.3% with a F1O2 of 1.0. Significant improvement was observed within 30 min after starting SHFJV with inhaled NO (paO2 282.9 mm Hg; oxygen saturation 99.5%). There were no differences observed in hemodynamic parameters between CMV and SHFJV. Although the pulmonary status of the patient improved, the patient died due to therapy-resistant hemodynamic failure. CONCLUSION. It will take further studies to judge whether the success of this new ventilation strategy is reproducible and if the improvement of the oxygenation is more pronounced when adding inhaled NO to SHFJV than when each technique is applied separately.

Anesthetics, Inhalation↗
PubMed1995

[Behavior of cerebral blood flow velocity in conventional ventilation and superimposed high frequency jet ventilation].

OBJECTIVE: 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. METHODS: 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 which correlates closely to the cerebral blood flow, was measured continuously with transcranial Doppler ultrasound. RESULTS: CMV: Increased hyperventilation leads to a statistically significant increase in paO2 (121.3 to 147.2 mmHg, p < 0.05), SaO2 (98.5% to 99.2%, p < 0.05) and decrease in BFV (systole 115.9 to 89.6 cm/s, diastole 44.6 to 31.8 cm/s, p < 0.05). Heart rate, mean arterial blood pressure, ICP and ventilation parameters did not show any statistically significant differences. SHFJV: During SHFJV the parameters demonstrated similar patterns as during CMV. However, none of the changes were statistically significant (paO2 111.9 to 125.9 mmHg, SaO2 97.9 to 98.8, BFV systole 106 to 95 cm/s, diastole 52.7 to 42.4 cm/s, n.s.). After calculating the mean BFV according to the Markwalder formula to a standard paCO2 of 40 mmHg CMV and SHFJV were compared to one another. No statistical difference was seen between the two different ventilation techniques. CONCLUSION: In patients with increased ICP, pulmonary complications such as pneumonia or ARDS are frequently observed. Since there are indications that SHFJV is of benefit in pulmonary insufficiency, the study was conducted to demonstrate that SHFJV can be safely applied in patients with increased ICP.

Adolescent↗
PubMed1995

[Ventilation during tracheotomy in extensive, 90% laryngeal stenosis using superimposed high frequency jet ventilation via the jet laryngoscope].

In a 35-year old male patient with laryngeal carcinoma an acute respiratory insufficiency with early hypoxaemia developed due to massive laryngeal stenosis. An endotracheal intubation was not possible since the available lumen was too small. Tracheotomy using local anaesthesia was not possible since spontaneous respiration with a Venturi mask applying 100% oxygen was not sufficient and the patient was becoming restless and agitated due to the hypoxaemia. Transcutaneous jet ventilation was considered to be too risky since the needle would have to pass highly vascularised tumour tissue and the detection of such a small rest lumen would have been quite difficult. Ventilating the patient using a percutaneous catheter would have been very risky as well since, due to the massive stenosis, a sufficient expiration would not be likely and therefore was considered to carry a high risk of barotrauma. The patient was ventilated under general anaesthesia via a specially designed endoscopy tube with integrated jet nozzles applying superimposed high frequency jet ventilation above the stenosis. Since it was possible to achieve sufficient ventilation during the inspection of the larynx the jet laryngoscope was left in place and the supporting apparatus was covered with sterile drapes. The tracheotomy was performed using the superimposed high frequency jet ventilation. Throughout the procedure oxygenation and ventilation were adequate. The laryngectomy performed several days later revealed a cauliflower type protrusion into the tracheal lumen and a 5 cm long stenosis of the larynx with a lumen of 3 mm.

Adult↗
PubMed1994

[Jet ventilation superimposed on a special jet laryngoscope for endoluminal stent insertion in the tracheobronchial system].

BACKGROUND: Stenotic processes of the tracheobronchial system may lead to dyspnoea that can become lift-threatening. To restore sufficient function of the blocked airway, a silicone stent can be inserted. The anaesthesia techniques used for this intervention so far have been complicated. The object of this study was to determine whether the super-imposed high-frequency jet ventilation (SHFJV) via the jet laryngoscope originally designed for microlaryngeal surgery can be utilized for endoluminal stent insertion. METHODS: In 12 patients with acute respiratory insufficiency (ASA 3-5) due to stenosis of the tracheobronchial system, an endoluminal silicone stent was inserted through the jet laryngoscope while the patient was ventilated using SHFJV: RESULTS: A significant rise in paO2 readings prior to the jet ventilation and subsequent measurements was observed. The CO2 elimination was good (average paCO2 31.5 +/- 7.5-53.1 +/- 14 mmHg). Variably high paCO2 readings during stent insertion were related to the respective surgical phases. At the end of the surgical manipulation, all patients had sufficient spontaneous ventilation. CONCLUSIONS: First clinical applications of the jet laryngoscope combined with superimposed jet ventilation for stent insertion demonstrated satisfactory results. Not only were the patients ventilated throughout the procedure, but CO2 elimination was also satisfactory. Superimposed jet ventilation provides a sufficient tidal volume with low ventilation pressures, and therefore oxygenation and CO2 elimination are unproblematic. SHFJV enables the anaesthetist to ventilate the patient nearly continuously with minimal phases of apnoea. The only apnoea phases, as with any other method, occur during surgical manipulation while inserting the stent and thus blocking the airway. We believe that the jet laryngoscope with SHFJV presents a distinct advantage for both anaesthetist and surgeon when inserting stents in the tracheobronchial system.

Acute Disease↗
PubMed1994

[Anesthesia in acute respiratory tract obstructions caused by high degree laryngeal and tracheobronchial stenoses].

UNLABELLED: Stenotic process of the laryngeal and/or tracheobronchial system may lead to dyspnoea which can become life threatening. OBJECTIVE: The object of our study was to determine whether sufficient gas exchange can be ensured in patients with a massive stenosis of the respiratory tract applying the Superimposed High-Frequency-Jet-Ventilation (SHFJV) via the jet laryngoscope. Further, it was to be determined whether SHFJV can be applied for insertion of endoluminal stents into the tracheo-bronchial system. METHOD: SHFJV was applied using the Bronchotron-ventilator (capable of generating simultaneous low frequency and high frequency jets) and the laryngoscope, basically a modified endoscopy tube permitting simultaneous application of two jet modes. SHFJV was performed in 14 patients (including 4 children) suffering from massive laryngeal stenosis and in further 12 patients with stenosis of the tracheo-bronchial system. In all patients total intravenous anaesthesia was performed. RESULTS: In the patients with laryngeal stenosis the average paO2 was 117.5 +/- 43 mmHg, and the mean paCO2 47.3 +/- 11.6 mmHg. In the patients with stenosis of the tracheo-bronchial system the mean paO2 was 125 +/- 77 mmHg and the average paCO2 53.3 +/- 18 mmHg. CONCLUSIONS: The SHFJV technique presents the possibility to ventilate the patients continuously for surgical procedures even with massive stenosis of the respiratory tract. The application of SHFJV via the jet laryngoscope not only enables the anaesthesist to ventilate this group of patients but also helps the surgeon and therefore results in more safety for the patient.

Adult↗
PubMed1994

[Ventilation in laryngeal laser-surgical interventions using superimposed high frequency jet ventilation (SHFJV)--a further revision of jet ventilation technique for laryngeal interventions].

In laser surgery of the larynx the surgeon and the anaesthesist have to compete for the limited space available. The surgeon requiring good visibility and an undisturbed operating area whereas the anesthetist has to ensure sufficient ventilation of the patient. Further, complications of anaesthesia and laser must be avoided. These requirements are met by using the jet-tube (jet-laryngoscope) with two integrated nozzles applying simultaneously low- and high-frequency jet-ventilation giving the surgeon total access to the area operated on, and at the same time enables safe ventilation of the patient. Of 334 operations with the tubeless ventilation technique 76 cases were laser surgical interventions. In 6 patients stenoses were enlarged. The average duration of the jet-ventilation was 25 +/- 10 minutes. The maximum duration of a laser surgical intervention was 140 minutes. The age distribution of the patients was 18 months to 82 years. In all patients pulmonary gas exchange was satisfactory. We believe that the advantage of the tubeless jet-ventilation is: optimal visibility and surgical freedom for the surgeon, no time limitation, even in very severe stenoses. Since no volatile anaesthetics or any type of endotracheal tube are applied there is no danger of interaction with the laser when using the SHFJV via the jet-laryngoscope. Application of the tubeless jet-ventilation technique is however limited if patients suffer from severe pulmonary obstruction; likewise highly obese patients and patients in whom massive bleeding occurs are not amenable to tubeless jet-ventilation.

Adult↗
PubMed1994

[Tubeless superimposed high frequency jet ventilation in high grade laryngeal stenoses].

UNLABELLED: Massive stenosis of the larynx may present a potentially life-threatening situation for the patient, requiring immediate measures to ensure a patient's airway. The aim of this prospective study was to evaluate potential benefits of Superimposed High Frequency Jet Ventilation (SHFJV) in patients requiring microlaryngeal surgery due to massive stenosis of the larynx. PATIENTS AND METHODS: 23 patients (age range 1.5 to 90 years) with laryngeal stenosis grade 2 and 3 according to the Cotton scale were ventilated using SHFJV. The duration of the SHFJV was 12 to 116 minutes. SHFJV was performed using a Bronchotron Respirator via a jet-laryngoscope. RESULTS: Arterial blood gases demonstrated paO2 between 71 and 295 mmHg and paCO2 of 28 to 81 mmHg. The mean FiO2 applied was 61.75 +/- 19.26. The airway pressure was measured at the tip of the jet-laryngoscope and was between 6 and 15 mmHg, and PEEP was 1 to 5 mmHg. In 13 patients a CO2 laser was utilised during surgery. DISCUSSION: In all patients SHFJV was performed without problems. Since the ventilation is delivered above any possible stenosis the danger of barotrauma is minimised. The surgeon obtains optimal visibility of the larynx and is not obstructed in the surgical procedure. SHFJV enables both the surgeon and the anesthetist to perform their respective duties and therefore increases the safety of the patient in the management of such a difficult problem as massive stenosis of the larynx.

Adolescent↗
PubMed1994

[3-D endoscopy for laryngeal interventions in tubeless superimposed high frequency jet ventilation. A clinical trial].

UNLABELLED: Surgery by 3-dimensional (3D) endoscopy is being used routinely in abdominal surgery and, in special cases, in thoracic surgery; however, it has not been reported to be used in laryngeal surgery. METHODS: We inserted a 3-D endoscope into a jet laryngoscope and studied the pressure properties at the tip of the jet laryngoscope as well as the intrapulmonary pressures while applying SHFJV. The studies were conducted initially using a lung simulator, and then in 6 patients undergoing endoscopic laryngeal surgery. RESULTS: Due to the rather large 3-D endoscope the diameter of the jet laryngoscope was reduced between 25.2% and 70.9% depending on the size of the jet laryngoscope. The measurements on the lung simulator revealed that the reduction of the diameter of the jet laryngoscope 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 airway pressure was 19 +/- 5.3 mmHg prior to the insertion of the endoscope and 12.3 +/- 6.9 mmHg after the insertion. The mean PEEP values increased from 2 +/- 0.6 to 3.6 +/- 2.3 mmHg. Reduction of the working pressure resulted in regaining the initial inspiratory pressures and tidal volumes. CONCLUSIONS: In the clinical application of 3-D endoscopy via a jet laryngoscope it was possible to achieve sufficient ventilation, inspection of the surgical field and performance of the surgical procedure. A CO2 laser was used without changing the ventilation regime.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗