[Bronchial asthma and chronic obstructive pulmonary disease with acute exacerbation: preclinical differential diagnostic and emergency treatment]. / Asthma bronchiale und chronisch obstruktive Lungenerkrankung mit akuter Exazerbation: Präklinische Differenzialdiagnostik und Notfalltherapie.

Chronic obstructive pulmonary disease (COPD) and bronchial asthma are the most common causes of obstructive pulmonary diseases and acute dyspnoea. In the preclinical emergency situation a distinction between bronchial asthma and exacerbated COPD is difficult because symptoms are similar. Although the preclinical measures differ only marginally, a differential diagnosis from other causes of respiratory obstruction and acute dyspnoea, such as cardiac decompensation, anaphylaxis, aspiration of foreign bodies, tension pneumothorax and inhalation trauma is necessary because alternative treatment options are required. In the treatment of COPD and bronchial asthma inhalative bronchodilatory beta(2)-mimetics are the first choice especially for serious obstructive emergencies because there is an unfavorable relationship between effect and side-effects for the intravenous route. Dosable aerosols, nebulization and if necessary, continuous nebulization, are appropriate application forms even for serious obstructive crises with the need of a respirator. In these cases a minimal inspiratory flow in patients is not required. Theophylline only plays a minor role to beta(2)-mimetics and anticholinergics as a bronchodilator in asthma and COPD guidelines, even in serious obstructive diseases. For severe asthma attacks the administration of magnesium is a possible additional option. Systemic intravenous administration of steroids has an anti-inflammatory effect and for this reason is the second column of treatment for both diseases. Invasive ventilation remains a last resort to ensure respiratory function and indications for this are given in patients with clinical signs of impending exhaustion of breathing.

Tremor analysis in two normal cohorts.

OBJECTIVE: Quantitative tremor analyses using almost identical methods were compared between two independent large normal cohorts, to separate robust measures that may readily be used diagnostically from more critical ones needing lab-specific normalization. METHODS: Hand accelerometry and surface EMG from forearm flexors and extensors were recorded with (500 and 1000 g) and without weight loading under postural conditions in 117 and 67 normal volunteers in two different specialty centers for movement disorders in Germany. RESULTS: Tremor amplitude (total power) and frequency fell within a similar range but differed significantly. A significant reduction of tremor frequency under 1000 g weight load (>1 Hz), and a lack of rhythmic EMG activity at the tremor frequency in around 85-90% of the recordings were robust findings in both centers. CONCLUSIONS: The differences in frequency and total power indicate that these measures critically depend on the details of the recording conditions being slightly different between the two centers. Thus each lab needs to establish its own normative data. We estimate that at least 25 normal subjects have to be recorded to obtain normal values. The reduction of tremor frequency under load and lacking tremor-related EMG activity were well reproducible allowing a differentiation of physiological from low amplitude pathological tremor. SIGNIFICANCE: This study provides a framework for more standardized tremor analyses in clinical neurophysiology.

Effects of ambient cold and depth on lung function in humans after a single scuba dive.

This study evaluated the subacute respiratory effects of diving, to try to separate the effects of ambient temperature from those of depth. In the first experiment 10 healthy men made a compressed-air dive to 50 m that exposed them to cold. They were compared with 10 matched control subjects who underwent the same dive profile but were exposed to a comfortable temperature. In the second experiment 16 healthy subjects made randomized cold dives to both 50 m and 10 m. Pulmonary function tests were made before, after 1 h, and 24 h after the dives. In the first experiment there was an increase in residual volume (P < 0.05) and a decrease in forced expiratory volume at 1 s (FEV1), in forced vital capacity (FVC) and in mid-expiratory flow at 75% of FVC (MEF75) 1 h after the cold dives (P < 0.05). In the second experiment significant increases in specific airways resistance (sR(AW)) (P < 0.05) and decreases in FEV1 (P<0.01), in MEF75 (P<0.05), and in mid-expiratory flow at 25% of FVC (P<0.05), were obtained after the 50 m-dives, whereas SR(AW) increased after the 10 m-dives (P<0.05). The respiratory pattern observed 1 h after cold dives to 50 m indicated airway narrowing. The changes after cold dives to 10 m, however, were of minor magnitude. Both cold and depth seemed to contribute to the adverse effects of a single compressed-air dive on pulmonary function.

Neurologic outcome of controlled compressed-air diving.

The authors compared the neurologic, neuropsychological, and neuroradiologic status of military compressed-air divers without a history of neurologic decompression illness and controls. No gross differences in the neuropsychometric test results or abnormal neurologic findings were found. There was no correlation between test results, diving experience, and number and size of cerebral MRI lesions. Prevalence of cerebral lesions was not increased in divers. These results suggest that there are no long-term CNS sequelae in military divers if diving is performed under controlled conditions.

Magnetic resonance signal abnormalities and neuropsychological deficits in elderly compressed-air divers.

We investigated the association between MR signal abnormalities of the central nervous system, neuropsychologic performance and exposure indices in 20 experienced elderly compressed-air divers who had no history of neurological decompression illness (DCI). Results of MRI of the brain and psychometric testing were compared with 20 matched healthy commercial employees who never dived: 60% of the divers and 45% of the controls had hyperintense MR abnormalities. Among divers, both the number and the size of abnormalities correlated with hours diving in the deep air-diving range of 40-60 m (p < 0.05). Divers' mental flexibility and visual tracking performance were decreased in comparison with controls (p < 0.05 and p < 0.01). Divers thus are at risk of detrimental long-term effects of compressed-air diving on the central nervous system even in the absence of a history of neurological DCI.

Expiratory flow limitation in compressed air divers and oxygen divers.

Divers are exposed to dense gases under hyperbaric and hyperoxic conditions and, therefore, may be at risk of developing respiratory disease. Long-term effects on respiratory function have been found in commercial divers who perform deep dives. This study was conducted to detect possible lung function changes in scuba divers who dive in shallow water using compressed air or oxygen as a breathing gas. A cross-sectional sample of 180 healthy male divers (152 air divers and 28 oxygen divers) and 34 healthy male controls underwent a diving medical examination including body plethysmography, diffusion capacity measurement and a cold-air isocapnic hyperventilation test (CAIH). Air divers and oxygen divers had a lower mid-expiratory flow at 25% of vital capacity (MEF25) than controls (p<0.01 and p<0.05, respectively). Oxygen divers also had a decreased mid-expiratory flow at 50% of vital capacity (MEF50) (p<0.05). Divers' groups and controls did not differ with respect to age, smoking or medical history. The prevalence of airway hyperresponsiveness to CAIH was 1.4% (n=3 divers). MEF25 and MEF50 were inversely related to years of diving (p<0.01 and p<0.001, respectively). The pattern of lung function changes obtained in scuba divers is consistent with small airways dysfunction and the association between diving exposure and lung function changes may indicate long-term effects on respiratory function.

Atopy, airway reactivity and compressed air diving in males.

A decline in expiratory flow rates in divers has recently been attributed to chronic exposure to hyberbaric air. Airway hyperresponsiveness (AHR) to stimuli due to a hyperbaric environment may play a certain role in this context. The aim of this study was to determine the prevalence of AHR in compressed air divers and to assess the value of bronchial challenges for prediction of fitness to dive. A cross-sectional sample of 59 healthy male volunteers--28 divers and 31 diving candidates (controls)--who had been found fit to dive in a diving medical examination underwent additional allergy screening (skin prick and serum IgE) and a histamine bronchial challenge. Pre- and postchallenge body plethysmography was completed to assess AHR. AHR to histamine was significantly increased among divers and positively related to diving experience whereas divers and controls did not differ significantly with respect to age, anthropometric data, current smoking habits, skin prick reaction, and elevated serum IgE. Our results indicate an increased prevalence of AHR to nonspecific inhalation stimuli in experienced divers. Bronchial challenge tests may be helpful to detect asthmatics in the medical assessment of fitness to dive and for follow-up examinations during a diver's career.

Development of spatial memory and spatial orientation in preschoolers and primary school children.

The present study addresses the question of what kind of information children use when orientating in new environments, if given proximal and distal landmarks, and how spatial memory develops in the investigated age groups. Ten 5-year-old, ten 7-year-old and ten 10-year-old children were presented with the 'Kiel Locomotor Maze', containing features of the Radial Arm Maze and the Morris Water Maze, in order to assess spatial memory and orientation. Children had to learn to approach baited locations only. Task difficulty was equated with respect to the children's age. Training was given until the children reached criterion. During testing, the maze configuration and response requirements were systematically altered, including response rotation, cue rotation, cue deletion and response rotation with cue deletion in order to assess the spatial strategies used by the children. During training and testing, working-memory errors (WM), reference-memory errors (RM) and working-reference memory errors (WR) were recorded. As expected, no difference between age groups appeared during training, thus confirming comparable task difficulty across age groups. During testing, age groups differed significantly with regard to the orientation strategy used. The 5-year-olds were bound to a cue strategy, orientating towards local, proximal cues. The 10-year-olds mastered all tasks, thus displaying a place strategy, being able to use distal cues for orientation, and were even able to do so after being rotated 180 degrees. The 7-year-olds proved to be at an age of transition: five of them were bound to a cue strategy, five children were able to adopt a place strategy. The differences in the orientation strategies used by children of different age groups was reflected by the sum of errors they made, also by RM. WM were found to be rare, especially in older children. We conclude that preschoolers use a cue strategy, that the development of place strategies occurs during primary school age and seems to be complete by the age of 10 years.

Retest reliability of spatiotemporal gait parameters in children and adults.

The objective of the study was to assess the retest-reliability of ten different gait parameters in healthy children (n=12; age 6-7 years) and adults (n=12; age 21-35 years) during free-speed locomotion on a simple walkway. Further the intra-subject variability of the stride dimensions was checked. On two occasions, spatial gait parameters were measured by footprint analysis, temporal dimensions were recorded using video-analysis. For spatial gait parameters, correlation coefficients (ICC, Pearson's r) between the test and the retest results were found to be high in adults and satisfying in children. The temporal parameters were less consistent. Generally the within-trial variability was higher in children than in adults. Conclusions: (i) The retest reliability for the measurement of the spatial gait parameters can be judged as high. (ii) For gait analysis in children it should be taken into account that gait parameters are more variable from trial to trial than in adults. Copyright 1997 Elsevier Science B.V.