[Ventilator weaning after long-term ventilation--the concept of a regional ventilator weaning center]

Long-term mechanical ventilation implies a significant number of weaning failures. The basis of this unweanability is chronic fatigue of the inspiratory muscles which is due to depletion of energy store (e.g. glycogen). Considering this pathophysiological principle, the decisive therapeutic option during weaning from long-term mechanical ventilation consists of resting the respiratory muscles. The commonly used assisted ventilation modes only partially relieve the respiratory muscles because the work of breathing is done both during the trigger phase and during the inspiratory cycle. The essential characteristic of our weaning concept includes the repeated determination of the spontaneous breathing frequency in awake patients, which is followed by controlled intermittent positive pressure ventilation with a slightly higher respiratory rate. Ideally, this results in total suppression of the activity of the breathing centre, and in subsequent relief and recovery of the respiratory muscles by replenishing the energy stores. The close succession of relief and training periods avoids inactivity-induced atrophy of the respiratory muscles and permits regeneration. Additionally, our weaning concept avoids increases in inspiratory work during the phases of spontaneous breathing. This means that high-resistance small-caliber endotracheal tubes have to be replaced by large tubes. Moreover, transtracheal oxygen insufflation during spontaneous breathing decreases anatomic dead space. This reduces minute ventilation and, therefore, the work of breathing. In patients still exhibiting chronic fatigue of the respiratory muscle pump after successful weaning, intermittent home ventilation is initiated via a breathing mask. Apart from the concept described above, successful weaning from the respirator after long-term ventilation is based upon dedicated patient care and depends on the architectural characteristics of the intensive care unit.

[Value of transtracheal oxygen insufflation in the weaning period after long-term ventilation]

BACKGROUND

In many cases, respiratory muscle failure is the reason for unsuccessful weaning attempts after long-term ventilation. Therapeutic measures must therefore be aimed at unloading the respiratory pump. In this present study we examined whether, in particular, the transtracheal O2-insufflation (TTO2) results in a change of breathing patterns and unloads the respiratory muscles.

PATIENTS AND METHODS

We examined 6 patients (5 males, age 65.6 +/- 3.9 years, diagnosis: chronic obstructive lung disease), who received long-term mechanical ventilation in outward intensive care units. Baseline resting data (arterial blood gas analysis, the breathing frequency and the minute volume) were obtained with the patients breathing room air for 1 hour. After receiving TTO2 with a flow of 21/min for another 1-hour-period the measurements were repeated.

RESULTS AND CONCLUSION

In our study we could show that the TTO2 leads to an impressive decrease in inspiratory work of breathing-relative to the minute ventilation by about 28%. Therefore TTO2 is of great importance in the weaning phase subsequent to prolonged mechanical ventilation due to the respiratory muscle failure.

[Increase in hypercapnia in exercise--an unloading strategy?]

BACKGROUND

Chronic hypercapnia seems to preserve the overloaded respiratory pump from manifest muscle failure. In order to get information about the regulation of the ventilation under exercise we investigated clinical stable hypercapnic patients.

PATIENTS AND METHODS

Twenty-one patients (20 males, 53.7 +/- 13.2 years) with obesity-hypoventilation syndrome (8), chronic obstructive lung disease (4), scoliosis (3), myopathy (2) and post-Tbc (2) were examined. Ventilation parameters (fb, Vt, VO2), respiratory muscle strength (PImax, PEmax), arterial blood gases (pO2, pCO2), respiratory quotient (RQ) and lactate were measured at rest and at the end of 5 minutes of maximal bicycle exercise. The control group consisted of 10 healthy persons.

RESULTS AND CONCLUSIONS

A significant augmentation of the pre-existing hypercapnia under exercise (reflecting hypoventilation in relation to the predicted value) was observed in all patients with chronically overloaded respiratory muscles. This mechanism seems to be wise because it protects the respiratory pump from failure.

[Effect of a face mask on work of breathing in patients with chronic obstructive respiratory disease]

Resistive loading associated with breathing through a face mask (surgeons' paper mask) increases work of breathing significantly after a prolonged period of wearing. The additional resistive breathing due to a face mask may be intolerable for patients with preexisting overloaded respiratory muscle pump and contribute to inspiratory muscle fatigue.

[Intermittent self-ventilation. Therapy of chronic respiratory pump fatigue]

Chronic fatigue of the respiratory pump may be due either to constant overexertion of otherwise healthy muscles of respiration (e.g. due to chronic obstructive lung disease, scoliosis) or to certain neuromuscular diseases (e.g. Duchenne type muscular dystrophy). Intermittent self-ventilation (ISV) is employed--in particular at night--in order to prevent imminent exhaustion of the respiratory muscles. The relief provided by ISV gives the muscles a chance to recover. The muscles of respiration can be largely rested by the use of volume-controlled ventilation (IPPV), or partially rested by-BiPAP ventilation (Stimotron). Two main approaches to ventilation are available: non-invasive via a breathing mask or, if this is not possible, invasive ventilation via a tracheostomy. In addition to the commercially available standard nasal masks, we more often make use of custom-made so-called Grafschaft nose-and-mouth masks. The early provision of support for the muscles of respiration can obviate, or at least delay, the need for emergency intubation and subsequent assisted ventilation in an icu in endangered patients.

[Evaluation of a portable device for measuring maximal inspiratory pressure (Pimax)]

Pimax measurement is useful for quantifying the fatigue of the respiratory muscles (the "respiratory pump" of the mechanics of respiration), for controlling the therapeutic effect of artificial respiration performed at home, and assessment of the possibility of relieving a patient from artificial respiration. So far, such measurement had required complicated set-ups. A portable alternative is now available for Pimax measurement (MPM, distributed by Medanz, Starnberg, Germany). In a prospective study we compared the Pimax values measured via the mouth pressure measuring instrument under test, with the standard laboratory method. Statistical comparison of the measured data yielded a high degree of correlation (r = 0.97) with slight scatter of the individual data around the identity line. The portable instrument tested in this manner thus represents a mobile method yielding reliable Pimax values both on an inpatient and an outpatient basis.

A new oxygen applicator for simultaneous mouth and nose breathing

We have developed a new O2 applicator to try to overcome the problems of long-term oxygen therapy that ensures a sufficient oxygen supply for both nasal and oral breathing and prevents mucosal irritation. Placed on the upper lip, it is unobtrusive. The principle is as follows: due to an enlarged outlet area, turbulence occurs and the oxygen is reduced. Thus, an oxygen cloud is formed that can be inhaled by both mouth or nose. The efficiency of our O2 applicator was compared with a face mask in six healthy subjects and patients with COPD. A similar increase in PO2 was found up to an oxygen flow of 2 L/min for nasal and oral breathing. Mild hypercapnia resulted in three patients with COPD only when a face mask was used and only when patients breathed through the nose. All patients preferred the new applicator.

[Imaging of the normal anatomy of the hand using high resolution magnetic resonance tomography and surface coils]

Magnetic resonance imaging can visualize the soft tissue and the bone marrow of the hand. High spatial resolution requires the use of a surface coil. Signal-to-noise contrast was measured and compared for 3 different coils. Optimal results were obtained with a surface coil with a diameter of 8.5 cm. The wrist and the fingers of 10 volunteers each were examined. Images with a high spatial resolution and a good signal/noise contrast were obtained, enabling the delineation of small structures like Gynon's channel and the median nerve.

A double-blind study of two dosage regimens of lomefloxacin in bacteriologically proven exacerbations of chronic bronchitis of gram-negative etiology

Lomefloxacin has been shown to produce high and sustained concentrations in serum and bronchial mucosa after once-daily administration. This study was designed to assess whether a dose response exists for 400 mg lomefloxacin given once daily or twice daily for 10 days in the treatment of acute bacterial exacerbations of chronic bronchitis of gram-negative etiology. A total of 100 adult patients with acute exacerbations of chronic bronchitis were enrolled at 10 study sites in Germany. Patients with confirmed bacterial pathogens in the baseline sputum culture (once-daily group n = 49, twice-daily group n = 47) were eligible for analysis of bacteriologic and clinical efficacy. The eradication rates for the most frequently isolated baseline pathogens, Haemophilus influenzae, Pseudomonas aeruginosa, and Klebsiella pneumoniae, were at least 75% for both treatment regimens. Overall, once-daily treatment eradicated baseline pathogens in 42 of 49 (85.7%) patients, while twice-daily treatment eradicated pathogens in 43 of 47 (91.5%). This difference was not statistically significant (p = 0.226). Clinically, 47 of 49 (95.9%) patients in the once-daily group and 46 of 47 (97.9%) in the twice-daily group were cured or improved (p = 0.307). Both regimens were well tolerated; there were no differences in the incidence (six patients in each group), types, or severity of adverse events, nor was there clinical evidence of theophylline interaction. The results of this study demonstrate that once-daily treatment with 400 mg lomefloxacin is as effective as twice-daily dosing with 400 mg in patients with acute bacterial exacerbations of chronic bronchitis.

[Problems of the reproducibility of the inhaled dosage exemplified with the Pari provocation test I apparatus]

The unspecific bronchial provocation test--usually performed with histamine, metacholine or carbachol--is used to determine whether bronchial hyperreactivity is present, and to what degree. Epidemiological studies have shown, that an overlap exists between "healthy" and "sick". There are several reasons for this, the most important being the insufficient reproducibility of intrabronchial deposition and the fact that the total provocation dose is often unknown. The following factors must be taken into account to improve this situation: 1. Only those devices where the particle spectrum is not influenced by the inspiration flow (without additional airstream) should be used to produce aerosols. 2. The air current containing aerosols is vapour saturated when liquid aerosols are produced. As the vapour is derived from the nebulizing solution it forms part of the weight or volume loss, this can be up to 50% of the total weight/volume loss. The aerosol output is far more constant and practically independent of the vapour saturation and the temperature. The intrabronchial dose can therefore not be calculated according to the weight loss of the nebulizer, as this is incorrect. 3. The evaporation of the nebulizing solution leads to an increase in the concentration of the test substance, especially towards the end of the evaporation process. Thus, the volume of the nebulizing solution should always be as large as possible or renewed early. 4. The slower the inhalation maneuver, the less the reproducibility of the intrabronchial deposition is impaired. The intrabronchial deposition varies least, when a slow inspiratory vital capacity maneuver is carried out (inspiration time greater than 8 s). Exhalation should be normal or even rapid, as aerosol deposition is thus increased, due to airway collapse. Breath-holding at the end of inspiration, for about 3-4 seconds, is favourable. 5. The anatomy of the glottic region varies greatly interindividually, influencing intrabronchial deposition. To reduce this to a minimum, the average diameter of the particles should not exceed 2 microns. On the other hand, the diameter of particles should not be under 1 micron, as the inhaled amount of substance is then markedly reduced (volume approximately d3). 6. Reservoirs, storaging the aerosol before inhalation, increase reproducibility, since they stabilize the aerosol due to vapour saturation. Plastic reservoirs must either be of antistatic material, or made antistatic by being filled repeatedly. The reproducibility of intrabronchial deposition is in the range of +/- 15% for the PARI-Provokationstest device I, (determined by radioactive labelling).(ABSTRACT TRUNCATED AT 400 WORDS)

[Aerosol deposit sample in aspecific bronchial provocation test: a nuclear medicine study for quantification]

A method of standardization of inhalation bronchial provocation tests is induced. The distribution of radioactivity of in- and exhaled 99mTc human albumin (Venticoll) enables an exact calculation of intrabronchial aerosol deposition. The investigations were carried out at twelve normal test persons by using the device of bronchial provocation tests of PARI. Linearity exists between nebulized aerosol quantity in the bag and bronchial aerosol deposition. The intrabronchial aerosol deposition is calculated about 100 mg after emptying the ten liter-bag. Slowly inspiratory maneuvers of vital capacity produce a precision of the inhaled aerosol of about 15 percent.

Diagnostic modalities for detection of pulmonary embolism in clinical routine: a European survey

A questionnaire asking for routinely performed modalities to diagnose deep venous thrombosis (DVT) and pulmonary embolism (PE) was sent to 2,500 departments in 23 European countries. Five-hundred-seventy (23%) were received back and evaluated according to hospital size and regional differences. Countries were grouped into: Anglo-Scandinavian (a), German-speaking (g), and Roman (r). Contrast venography is most frequently performed (94%) to diagnose DVT, independent of hospital size and without regional differences. With exception of Doppler ultrasound (71%), noninvasive DVT tests are rarely performed (6-28%). To diagnose PE, pulmonary angiography (PA) and ventilation-perfusion (V-P) scintigraphy are performed in 71%, digital subtraction angiography in only 50%. Frequencies of PE tests strongly depend on hospital size (PA: small hospitals 53-66%, large 83-89%; V-P: small hosp. greater than 80%, large greater than 90%, with 2 exceptions: small German hospitals = 48%, primarily performing only P-scans and large Roman hospitals = 59%, primarily performing PA). Regional differences were also significant (PA: r = 85%, a = 74%, g = 63%, V-P: a = 95%, r = 66%, g = 63%, respectively).

[The value of 3D-CT in maxillary surgical diagnosis and therapy planning]

In 25 patients in whom oral surgery was required, we examined what additional information can be obtained via three-dimensional CT compared with conventional transverse CT scans. We showed that D-3 CT facilitated the spatial orientation by complex osseous destructions. Better therapy planning and postoperative control was therefore feasible. However, CT diagnosis continued to be based on transverse scans.

Acute and long-term amiloride inhalation in cystic fibrosis lung disease. A rational approach to cystic fibrosis therapy

Cystic fibrosis (CF) is the most common inherited fatal disorder among Caucasians. Bronchial mucus in CF contains more potassium and less sodium, which may be due to increased sodium absorption, resulting in a reduced airway water content. We studied 23 patients with CF after inhalation of normal saline or amiloride (10(-3) M), a sodium transport blocker. Mucociliary clearance (MC) and cough clearance (CC) were determined with a gamma camera that traced the movement of 99mTc-labeled, hardened erythrocytes over a 1-h period after the patients inhaled these particles as an aerosol. Before and after each investigation pulmonary function tests (PFT) and blood pressure (BP) were measured. Sputum thread formation was measured by means of a filancemeter. Six of the patients also completed a 3-wk trial of amiloride inhalation therapy. MC increased significantly (p less than 0.001) after acute amiloride inhalation (bronchial deposition, 0.07 mg amiloride) compared with that in the saline control. CC also increased, but not as much as MC. After 3 wk of amiloride inhalation (2 times a day) clearance values (both MC and CC) were markedly enhanced (p less than 0.01); after a similar period of saline inhalation, clearance values were not different from baseline. Sputum filance values also decreased significantly after amiloride inhalation. There were no adverse effects of the amiloride inhalation compared with saline. We conclude that amiloride inhalation administered as a single dose or as long-term therapy is able to increase MC and CC in CF airways and that the effect of 10(-3) M amiloride inhalation on MC lasts at least 40 min. (ABSTRACT TRUNCATED AT 250 WORDS)

[Double kidney with ectopic ureteral orifice: a case report]

An ectopic ureteric opening is a relatively rare malformation, diagnosed mostly in young age because of typical signs and symptoms and more often found in female patients. The diagnosis of this malformation in adults is unusual and can be difficult because of untypical signs and symptoms, as represented in the following case report.

[New technics for producing inhalation aerosols--initial experiences and results with the piezoelectric inhalation device]

In the treatment of chronic obstructive airway diseases, the inhalative application of medicaments with a bronchodilatory effect is given preference throughout the world. In addition to inhalation solutions and powder capsules, so-called metered-dose aerosols have formed an established part of the treatment plan for approximately 30 years now. With the piezoelectric inhalation device, a fully portable ultrasonic atomiser that is small enough to fit within the pocket, has been developed for the first time. In this device, the piezoelectric effect is utilised to produced, pressure-free, microfine aerosols. Within it, an accurately metered volume containing the therapeutic dose is applied to an atomising element oscillating in the ultrasonic range. The particle spectrum generated with the piezo-system corresponds, in terms of size, to that of metered aerosol devices, and the mean particle diameter is approximately 2.1 microns. The atomisation process takes approximately one second.

Aerosols for systemic treatment

The development of a new group of drugs (polypeptides) have recently increased the interest of alternative administration to the enteral route because of its proteolytic activity and the catabolism of the "first-pass effect." Aside from the "needle," the administration in the respiratory tract via aerosol is the method with the best efficiency. But several problems prohibited its spreading: (1) the accuracy and the reproducibility of the inhaled dose (range ca. 1:4); (2) the small amount of inhaled drug in relation to the dose in the aerosol delivery system (range ca. 1%-10%); (3) the fear of allergic reactions of the respiratory system; (4) the variability of the drug transport into the systemic circulation. New approaches and data raise hopes in reducing the problems: (1) aerosol delivery systems with defined particle spectrum and storage systems; slow vital capacity inhaling maneuver; (2) delivery systems that nebulizes nearly the total amount of drug; (3) all studies with the inhalation application of insulin, heparin, ergotamin, ribavirin, aminoglycosides, and "cigarette smoke" do not reveal any relevant allergic reaction; (4) many studies were performed in the last 10 years on the influence of substances and especially of diseases on the transport of molecules through the respiratory tract. Only a few of them are relevant (exogen allergic alveolitis, active sarcoidosis, active smoking). Aerosols for (exogen allergic alveolitis, active sarcoidosis, active smoking). Aerosols for systemic drug treatment seems to be a gained alternative to the "syringe."

[The value and consequences of nocturnal pulse oximetry in severe heart failure, suspected myocardial infarct and acute cerebral ischemia]

On extensive clinical monitoring of nocturnal oxygen saturation (Minolta Pulsox 7) we observed three groups with an increased risk of nocturnal hypoxemia. The hypoxemia was classified in terms of severity, frequency and duration into six groups of findings. The degree of oxygen desaturation was positively correlated to the severity of disease. In the group of patients with heart failure (NYHA III-IV) (n = 13) four had severe hypoxemia, and a history of previous cardiac infarction; three of them wore a pacemaker. Decrease in saturation after acute cerebral ischemia was seen in particular in patients with oropharyngeal disorders (dysphasia and dysphagia). In the group with suspected myocardial infarction (n = 16) we measured frequent short drops in saturation in ten patients, eight of whom were heavy snorers. Because of its simplicity, non-invasiveness and high information yield, especially in acute patients, pulse oximetry is important for clinical diagnosis, with immediate consequences for many patients.

[3-dimensional reconstructions of the skull, axial and extremity skeleton]

In a prospective study, 150 threedimensional reconstructions of patients with bone diseases were analyzed. It could be seen that 3 D images were relevant for therapeutic considerations in diseases of craniofacial bones, and to a lesser degree for other skeletal regions. In no case was the 3 D reconstruction the only important factor for the therapeutic decision. The study demonstrated that 3 D imaging of the pelvic bones, especially for necroses of the femoral head, is severely limited without the possibility of computer-aided disarticulation.

[Clinical and computed tomographic follow-up of conservatively treated disk prolapse]

Of a total of 238 patients suffering from root compression syndrome, 41 successfully conservatively treated patients were followed up both clinically and via CT. At follow-up time they were all largely free from complaints. 71% showed unchanged prolapse on CT examination. 29% had a moderate or marked regression of disk prolapse. All unchanged cases of prolapse were medial prolapses. The reason for regression of the sequestered disk tissue is discussed controversially and has not been satisfactorily clarified to date. Improvement of findings in unchanged prolapse is mainly explained by the adaptability of the root if there is enough space for shifting.

New method for easy labeling of beta-2-agonists in the metered dose inhaler with technetium 99m

The actual deposition pattern of micronized drugs from metered dose inhalers (MDI) is incompletely known because there are no methods available to label the drugs (beta 2-agonists) with gamma-emitters. Indirect measurements of the distribution of the drug in man differed greatly due to the method used. Our method uses the better solubility of 99mTcO4- in the beta 2-agonist-micronized drug in relation to the propellant with surfactant. The principle is to extract the 99mTcO4- from the original water phase into the liquid phase of the propellant with ethyl methyl ketone. For labeling the micronized drug particles, the original MDI must be cooled to -60 degrees C and some labeled propellant (including surfactant) with high specific activity of 99mTcO4- is added through an aperture in the bottom of the container. The aperture is sealed with a screw. After rewarming the MDI, more than 90% of the added 99mTcO4- is dissolved in the beta 2-agonist-micronized drug in relation to its volume. This is proved by comparing the distribution of the radioactivity component with chemical analysis. The pattern of deposition of both MDIs - placebo and beta 2-agonist-micronized drug - was shown to be similar in healthy volunteers. With a labeled MDI a preliminary study with 2 different inhaling maneuvers was performed in 7 volunteers: inhaling from residual volume after a pause of 2 s the intrabronchial deposition was 18.7%, and inhaling at 50% of vital capacity maneuver the intrabronchial deposition was 33.0%. The data obtained with actual measurement of the inhaled drug from MDI suggest greater intrabronchial deposition than was assumed before in the literature.

Deposition of aerosols and bronchial clearance measurements

A special inhalative device is described for reproducible deposition patterns of radioactive aerosols to measure mucociliary and tussive clearance and to evaluate the effect of drugs on the bronchial tree. Additive actions on mucus transport exist between beta 2-agonists and theophylline, but not in combination with inhalative quaternary ammonium compounds (ipatropium and oxitropium bromide). Mucolytics are generally less effective on mucociliary clearance than beta 2-agonists and theophylline, positive, negative and nonresponders are often seen due to the different viscoelastic properties of the mucus. Mucus transport is more than mucociliary clearance. Two-phase gas/liquid movement and coughing are also important transport mechanisms for bronchial mucus. Therefore, bronchodilators enhance mucus transport by increasing airway patency, which increases total and regional air flow and improves cough clearance.

[A new biopsy needle for transcutaneous histology procurement]

The new Vacu-Cut biopsy needle differs from previous types by its simpler manipulation and the production of a stronger vacuum to extract the tissue core. This vacuum is caused by withdrawal of a stylet through an air-tight sealing membrane. The instrument is a hollow needle with an inner cutting-edge and a diameter of 0.95 mm. 49 patients with suspected lesions of the pulmonary parenchyma were biopsied transcutaneously under x-ray monitoring. The biopsy material allowed a clearcut diagnosis in 44 patients, including 2 repeat biopsies; the success rate was thus 86% of all biopsies performed. 7 attempts (14%) did not yield useful material as the lesions were too small (diameter below 2.5 cm) or were not penetrated. In 35% of all biopsies small pneumothoraces were observed after a few hours. In two cases transitory hemoptysis occurred.

[Course of conservatively treated acute lumbar root compression syndrome. A computer tomography controlled study]

Of 129 patients with an acute lumbar root compression syndrome due to disc herniation 21, who were symptom-free, were examined by computed tomography (CT) on average 276 days after a three-step regimen of conservative treatment. In no instance had there been a deterioration of the original findings. In 14 patients the CT picture continued to demonstrate disc herniation, although the patients were without symptoms. In two patients a moderate, in five a marked regression of herniation was demonstrated by CT. Clinical improvement without change in the CT picture points to the compression syndrome not being explainable solely in mechanical terms. As a matter of fact, a possible cause may be a disturbance of radicular blood supply resulting in oedematous root swelling which is usually masked in the CT by prolapsed disc tissue. There is as yet no easy explanation for regression in case of prolapsed, perhaps even sequestered, disc tissue. It is possible that there have been reparative processes, such as have been described histopathologically in form of ingrown vessels. More plausibly would be a separation of the herniated and/or sequestered disc tissue in form of an asymptomatic sliding into the terminal caudal region.

Rapid regression of macroprolactinomas by the new dopamine partial agonist terguride

Two patients with macroprolactinomas were treated with the partial dopamine agonist, terguride. The prolactin (Prl) levels were lowered very effectively and in both cases the clinical symptoms improved markedly during the first days of treatment. Computerized tomography (CT) and magnetic resonance imaging (MRI) follow-up studies showed distinct tumour shrinkages which were first documented by MRI within 2 weeks of treatment. Tumour residues were, however, still demonstrable by MRI after more than one year respectively 3 months of therapy. In principal, results from both imaging techniques were comparable with the exception of the one year follow-up study of patient 1. In CT no residual tumour mass was visible whereas MRI showed only little reduction when compared to the 30th week scan. Throughout the treatment terguride was well tolerated without any side effects up to a maximal daily dosage of 3 mg given orally. Presumably the partial agonistic features of terguride contributed to the good tolerance of the treatment as compared to that of full dopamine agonists like bromocriptine of lisuride. Thus, these preliminary results indicate that terguride may be a beneficial alternative in the treatment of prolactinomas and other hyperprolactinaemic states.

Mucociliary clearance in smokers

The mucociliary clearance characteristics and the correlation between the extent of smoking and bronchial mucociliary dysfunction were studied in 71 smokers (15 without chronic bronchitis, 16 with simple and 40 with obstructive chronic bronchitis). Mucociliary clearance (MC) was measured with 99mTc-tagged human erythrocytes. Lung function values were determined by whole body plethysmography. All three smoking groups had significantly (p less than 0.001) lower TMC60.min rates (total MC in 60 min) on the average than the predicted values. The mean TMC60.min rates of heavy smokers with simple and obstructive chronic bronchitis were significantly (p less than 0.001) lower than that of light smokers without chronic bronchitis. There was no significant difference between the TMC60.min rates of smokers with simple and obstructive chronic bronchitis. The decrease in the MC rates was more pronounced in the central than in the peripheral airways. A significant (p less than 0.001) correlation was found between the extent of smoking (pack years) and the decrease of MC. The results suggest that the decrease of MC is an early functional abnormality in smokers, which precedes the development of symptoms of chronic bronchitis as well as functional detectability of airways obstruction.

CT of the postoperative lumbar spine: the value of intravenous contrast

Sixty-five patients with recurrent radicular complaints after operation for lumbar disc herniation underwent CT examination before and after intravenous contrast application (volume: 1.5-2.0 ml/kg body weight; flow rate: 0.35 ml/s). Postsurgical hypertrophic scar tissue showed definite contrast enhancement, whereas disc herniation remained unenhanced. Intravenous contrast application is recommended in patients previously operated upon for disc herniation.

[Magnetic resonance tomography in syringomyelia]

Thirteen patients with a clinical diagnosis of syringomyelia were examined by nuclear tomography (0.35 T magnet) in the spin-echo mode. In all thirteen patients, the T1 images (SE 400/35) showed a longitudinal cavity with a signal intensity of CSF. The shape and extent of the syrinx could be adequately demonstrated in 12 of the 13 examinations. Downward displacement of the cerebellar tonsils was seen in eight cases. The examination took between half and one hour. Advantages of magnetic resonance tomography (nuclear tomography) include the absence of artifacts, images in the line of the lesion and its non-invasiveness.

[Diagnosis of kidney diseases with magnetic resonance tomography including the use of nuclear magnetic resonance contrast media]

Magnetic resonance imaging of normal and pathological kidneys and the method of examination are demonstrated. The anatomy of the kidneys is excellently displayed by means of magnetic resonance imaging which can also distinguish between the renal cortex and renal medulla. Renal tumors and cysts can easily be recognized and differentiated by means of magnetic resonance imaging and the extension of the tumor (staging) can be defined. The principles of magnetic resonance imaging contrast media are described as well as the primary results obtained from administration of contrast media in volunteers. At the present time, ultrasound and computed tomography are the first imaging methods in recognition and differentiation of space occupying lesions of the kidneys. Magnetic resonance imaging should only be utilised in complicated cases, e.g. haemorrhagic cysts or when computed tomographic results show a suspected tumor invasion of the renal vein or tumor thrombus in the vena cava.