PubMed HealthSearch

Biomedical subjects

E Harzendorf

Publications and source records attributed to E Harzendorf.

16 recordsLinked to original sources

[Use of high frequency ventilation in patients with respiratory insufficiency].

High frequency ventilation is very common today for treatment of patients with respiratory insufficiency in the ICU as well as intraoperatively. This special kind of artificial ventilation is suitable for patients with decreased lung volume and reduced thoracic and lung compliance. Favourable results in the treatment of ARDS are described. During high frequency ventilation the same degree of oxygenation and CO2-elimination can be reached as with conventional mechanical ventilation. The resulting lower peak and mean airway pressure is advantageous. Therefore the barotrauma of the lung is reduced during high frequency ventilation. For these reasons high frequency ventilation is an alternative method for ventilation of patients with so called "stiff lungs" with reduced thoracic and lung compliance.

Acid-Base Equilibrium

[Equipment combination for the use of normal frequency and high frequency jet ventilation].

Over the last eight years high-frequency ventilation has been extensively evaluated both in the clinical and laboratory settings. Two types of jet ventilators for application of normofrequency and high-frequency jet ventilation have been developed. A combined equipment is described with gas mixer, heater-humidifier, monitoring, membrane solenoid valve and a special injection system.

High-Frequency Jet Ventilation

[Theoretical and experimental studies of the diagnostic relevance and comparability of mechanical oscillation parameters].

The practical application of the forced oscillation technique for the analysis of the mechanics of respiration is hampered by the fact that the measured frequency-dependent impedance values R(f) and X(f) cannot be related directly to the parameters airway resistance Raw and pulmonary compliance CL. Furthermore, various derived oscillatory parameters are employed which are not directly comparable even with one another. In order to be able to estimate the diagnostic relevance and comparability of the impedance curves R(f) and X(f), their form-specific characteristics R = R(5)-R(20) and X(5), as also the equipment-specific parameters Ros (Siregnost FD5) and Rfo (custo vit), the relationships of these oscillatory parameters to Raw and CL were simulated in a structural model of the respiratory system, and tested in the real system. It was shown that already from frequencies of f greater than 10Hz upwards, R(f) no longer reacts to an increase in resistance in the peripheral region of the lung, and at 20 Hz indicates only the upper airway component of a global obstruction demonstrated body-plethysmographically with Raw. The diagnostic information on peripheral airway obstruction is contained in both components R(f) and X(f) of the respiratory impedance; with increasing obstruction and increasing frequency, it progressively reverts to the X(f) curve. Therefore, by including X(f) in the resistance evaluation for the parameters Ros and Rfo, the underevaluation of R(f) as compared with Raw can in part be compensated for, although an overe stimation at low Raw values with Ros and a large scatter of the Rfo values in the case of large Raw figures has to be accepted.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance

[Experiences with the use of oscillating high frequency ventilation].

Our investigations have demonstrated that the effect of oscillatory high-frequency ventilation (HFO) on gas exchange in dogs is directly proportional to the oscillatory flow amplitude VM. Because of the equation: VM = PM/Z, gas exchange is increasing with rising oscillatory amplitude of the ventilation pressure PM and decreasing with rising impedance Z of the respiratory system. This system consists of endotracheal tube and the lungs of the dog investigated. The impedance Z = square root of R2 + X2 (resistance R and reactance X) achieves a minimal value near at the resonant frequency (reactance X = 0, in healthy intubated dogs near at 5 Hz) and increases with rising oscillatory frequency. Thus the oscillatory high-frequency ventilation is most effective near to the resonant frequency of the respiratory system. The results presented allow the conclusion that the application of high-frequency ventilation can be optimized by monitoring the respiratory mechanics parameters.

Animals

[Animal experiment studies of morphologic changes in the trachea and lung in high frequency ventilation].

Prolonged high frequency ventilation (24 hrs) in dogs leads to morphological changes in the trachea as well as in the bronchi. Erosive changes of tracheal epithelium were observed whereas small bronchi and bronchioli exhibited luminal obstructions by mucus plugs, caused by hypersecretion of goblet cells. Using histochemical methods degenerative changes of bronchiolar epithelium were observed.

Animals

[CT-guided sclerosing therapy of kidney cysts. Report of experience with 100 patients].

Due to its diagnostic accuracy as well as safe and accurate puncture technique CT can be used advantageously for percutaneous sclerosing therapy of renal cysts. CT-guided sclerosing therapy with pantopaque emulsions was carried out in 100 patients on an outpatient basis with altogether 107 solitary renal cysts. There were indications in all cases. Continuous follow-up of cyst involution in 96 patients with 103 cysts pointed out a reliable sclerosing effect in 95.1% of them. Major complications were neither registered in the puncture technique nor in the late urographic examinations.

Adolescent

[Results and assessment of ventilation and perfusion scintigraphic studies following left-sided homologous lung transplantation in the dog].

Left-sided homologous lung transplantations (LTP) were carried out in 18 mongrel dogs. Exhalation and perfusion scannings took place for interpreting the ventilation and perfusion in the postoperative course. The per cent Xe133 storage and the exhalation per minute show the significant reduction of the ventilation in the transplants dependent on the duration of the postoperative interval. The compensation behaviour of the ventilation of the non-operated lung shows the compartment analysis. The perfusion index QL/QR with Tc99m decreased progressively in the postoperative course.--These investigation methods are slightly invasive. They allow the synoptic recording of the relationships between ventilation and perfusion. A differential diagnosis of complications after lung transplantations is not possible, however.

Animals

[Diagnostic value of chest x-ray film in recognizing complications following homologous lung transplantation in the dog].

The postoperative controls of the course after unilateral homologous lung transplantation were interpreted by chest X-ray films of 86 dogs. Radiomorphologic findings in the transplanted lung had developed 69% of the surviving animals in the end of the 5th and 80% on the 9th postoperative day. The descriptive phenomena of the chest X-ray films were compared with the post-mortem findings concerning their etiology. Phenomena caused by rejection, by operation, and in a third group by rejection and operation could be separated statistically as to the temporal occurrence. - In that manner the partial or total shadow of the graft is a sign of rejection after the 5th postoperative day and the pneumothorax is a sign for a postoperative complication before the 5th day, on the other hand a phenomenon for the rejection after this time. - The radiologic findings are restricted by imperfect position of the animals during the radiograph and by overshadowing bony parts of the thorax. The diagnostic value of the chest X-ray film is reduced much, because the differential diagnosis to the radiomorphologic findings requires additional diagnostic methods for instance scintiscanning, angiography, bronchospirometry, and biopsy.

Animals

[Further development of the program system for lung function diagnostics running on minicomputer C 8205 (author's transl)].

Starting from the level of 1972 the development is characterized in view of -- general technical, psychological and economical problems -- completion of the program library and the -- technique of semi-on-line data collection. The last point describes experiences using the system of VEB Funkwert Erfurt. Different levels of automatization in lung function labs are discussed.

Computers