Volatile anaesthetics and the atmosphere: atmospheric lifetimes and atmospheric effects of halothane, enflurane, isoflurane, desflurane and sevoflurane.

The atmospheric lifetimes of the halogenated anaesthetics halothane, enflurane, isoflurane, desflurane and sevoflurane with respect to reaction with the hydroxyl radical (OH.) and UV photolysis have been determined from observations of OH. reaction kinetics and UV absorption spectra. Rate coefficients for the reaction with OH radicals for all halogenated anaesthetics investigated ranged from 0.44 to 2.7 x 10(-14) cm3 molec-1 s-1. Halothane, enflurane and isoflurane showed distinct UV absorption in the range 200-350 nm. In contrast, no absorption in this wavelength range was detected for desflurane or sevoflurane. The total atmospheric lifetimes, as derived from both OH. reactivity and photolysis, were 4.0-21.4 yr. It has been calculated that up to 20% of anaesthetics enter the stratosphere. As a result of chlorine and bromine content, the ozone depletion potential (ODP) relative to chlorofluorocarbon CFC-11 varies between 0 and 1.56, leading to a contribution to the total ozone depletion in the stratosphere of approximately 1% for halothane and 0.02% for enflurane and isoflurane. Estimates of the greenhouse warming potential (GWP) relative to CFC-12 yield values of 0.02-0.14, resulting in a relative contribution to global warming of all volatile anaesthetics of approximately 0.03%. The stratospheric impact of halothane, isoflurane and enflurane and their influence on ozone depletion is of increasing importance because of decreasing chlorofluorocarbons globally. However, the influence of volatile anaesthetics on greenhouse warming is small.

[High-frequency jet ventilation and the function of the right heart--an animal experimental study]. / Hochfrequenz-Jet-Ventilation (HFJV) und Funktion des rechten Herzens--Eine tierexperimentelle Studie.

In a controlled study, 10 dogs with normal and severely damaged lungs were subjected to nuclide angiocardiographic investigations into the function of the right ventricle. The pulmonary injury was produced by infusion of oleic acid (OA) into the right atrium during controlled ventilation (IPPV). The angiocardiographic examinations were performed using 133Xenon in the first pass technique. The study compared HFJV (HFJV 100, HFJV 300) with IPPV in the non-damaged lung as well as HFJV 300 with IPPV and CPPV (PEEP 1.0 kPa) after injury by OA. Whereas for the non-damaged lung no different right ventricular (RV) function between IPPV and HFJV was observed, the RV functional parameters after OA injury under HFJV showed, as opposed to CPPV, more favourable values on the whole. This became clear in particular in the significantly higher ejection fraction (RVEF) during HFJV. The RV function which is influenced during CPPV in terms of a favourable oxygenation is the consequence of an increased mean pressure in the airways with subsequent rise in the RV afterload and decrease in the RV preload. In contrast, the more favourable RV haemodynamics during HFJV are associated with a comparatively lower mean airway pressure and a significantly worse oxygenation. As the RV function also during HFJV has to be seen in direct dependence on the mean airway or intrapulmonary pressure necessary for sufficient oxygenation, the employment of this form of ventilation in the presence of an acute respiratory insufficiency has no impact on the RV haemodynamics different from the other compared forms of ventilation.

[Functional scintigraphic studies of perfusion and ventilation during high frequency jet ventilation (HFJV)]. / Funktionsszintigraphische Untersuchungen von Perfusion und Ventilation unter Hochfrequenz-Jet-Ventilation (HFJV).

In a controlled study, functional-scintigraphic investigations into perfusion and ventilation were performed on 10 dogs with non-damaged and extremely severely damaged lungs. The pulmonary damage was produced by injecting oleic acid (OA) into the right atrium of the heart under controlled ventilation (IPPV). The scintigraphic examinations were carried out using 133Xenon. The study compared HFJV (HFJV100, HFJV300) with IPPV in the non-damaged lung as well as HFJV300 with IPPV and CPPV (PEEP 1 kPa) after damage by OA. With the aid of the present radionuclide investigations, new insights can be gained into the largely unclear regional conditions of the gas exchange under HFJV in both the healthy and the damaged lung. Results from controlled studies on the distribution of ventilation and perfusion under HFJV have not been reported to date. The functional-scintigraphic examination with 133Xe on dogs shows, based on specific conditions of the gas exchange and special anatomic conditions of the lungs, a ventilation distribution that differs fundamentally from all other forms of ventilation, including HFOV, preference being given to apical pulmonary segments. This refers to the normal and the damaged lungs alike. However, ventilation-specific changes in pulmonary perfusion do not occur. The resulting deviating regional VA/Q relationship are obviously not of crucial influence upon the gas exchange. Rather, it is influenced and determined by damage-induced intraregional functional-structural alterations in the lung.

[The measurement of bronchial mucociliary clearance using 99mTc for evaluating the success of the salt water cure]. / Messung der bronchialen mukoziliaren Clearance mittels 99mTc zur Objektivierung des Erfolges der Solekur.

We found a highly significant improvement in the pulmonary mucociliary clearance in the peripheral region of the lungs four weeks after saline spring treatment. We examined the possibility of applying the saccharin sky-blue test for evaluating the success of spa treatment.