[Pneumologic aspects of diving medicine].
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Barotrauma↗
Biomedical subjects
K Tetzlaff
Publications and source records attributed to K Tetzlaff.
MR imaging of the central nervous system in diving-related decompression illness.
PURPOSE: This investigation was conducted to determine whether MR imaging showed cerebral or spinal damage in acute diving-related decompression illness, a term that includes decompression sickness (DCS) and arterial gas embolism (AGE). MATERIAL AND METHODS: A total of 16 divers with dysbaric injuries were examined after the initiation of therapeutic recompression. Their injuries comprised: neurological DCS II n = 8; AGE n = 7; combined cerebral-AGE/spinal-DCS n = 1. T1- and T2-weighted images of the brain were obtained in 2 planes. In addition, the spinal cord was imaged in 7 subjects. The imaging findings were correlated with the neurological symptoms. RESULTS: MR images of the head showed ischemic cerebrovascular lesions in 6/8 patients with AGE but showed focal hyperintensities in only 2/8 divers with DCS. Spinal cord involvement was detected in 1/7 examinations, which was the combined cerebral-AGE/spinal-DCS case. There was agreement between the locations of the documented lesions and the clinical manifestations. CONCLUSION: MR readily detects cerebral damage in AGE but yields low sensitivity in DCS. A negative MR investigation cannot rule out AGE or DCS. However, MR is useful in the examination of patients with decompression illness.
Adult↗
Computed tomography of the chest in diving-related pulmonary barotrauma.
Arterial gas embolism due to barotrauma of the lungs is a severe complication in compressed air diving. Precipitating factors are often missed on plain chest radiology. This study was conducted to detect occult lung disease predisposing to the development of pulmonary barotrauma in conditions associated with a change in ambient pressure. During the past 4 years, 11 patients who have suffered pulmonary barotrauma with or without subsequent development of cerebral or spinal arterial gas embolism underwent computed tomography of the chest several days post-injury. Examinations were conducted either using the conventional technique (n = 7) or, more recently, in the spiral mode (n = 4). Chest radiographs were available in all cases. In five patients CT revealed subpleural emphysematous blebs or cysts that were not detected by conventional radiography. Follow-up studies performed in two of these cases several months post-injury showed that the cystic lesions did not resolve. We assume that the lung cysts or blebs are preexisting conditions which caused pulmonary barotrauma. Computed tomography of the chest, preferably in the spiral mode, is recommended in any case of suspected pulmonary barotrauma in order to evaluate the possibility of pre-existing pathology and to predict future fitness to dive.
Adult↗
Risk factors for pulmonary barotrauma in divers.
STUDY OBJECTIVES: Pulmonary barotrauma (PBT) of ascent is a feared complication in compressed air diving. Although certain respiratory conditions are thought to increase the risk of suffering PBT and thus should preclude diving, in most cases of PBT, risk factors are described as not being present. The purpose of our study was to evaluate factors that possibly cause PBT. DESIGN: We analyzed 15 consecutive cases of PBT with respect to dive factors, clinical and radiologic features, and lung function. They were compared with 15 cases of decompression sickness without PBT, which appeared in the same period. RESULTS: Clinical features of PBT were arterial gas embolism (n=13), mediastinal emphysema (n=1), and pneumothorax (n=1). CT of the chest (performed in 12 cases) revealed subpleural emphysematous blebs in 5 cases that were not detected in preinjury and postinjury chest radiographs. A comparison of predive lung function between groups showed significantly lower midexpiratory flow rates at 50% and 25% of vital capacity in PBT patients (p<0.05 and p<0.02, respectively). CONCLUSIONS: These results indicate that divers with preexisting small lung cysts and/or end-expiratory flow limitation may be at risk of PBT.
Adult↗
Mathematical model for the calculation of oxygen concentrations in a closed circuit oxygen rebreathing apparatus.
BACKGROUND: Closed circuit oxygen rebreathing diving apparatus are used by armed forces in special tasks because of their advantages of long endurance, low noise and minimal gas escape. There is little knowledge about the administered oxygen concentrations in these systems. Closed circuit oxygen rebreathing apparatus are also used as a first aid device for the treatment of severe disorders. Because of similar constructive components, these rebreathing apparatus are comparable to the Dräger LAR V model. HYPOTHESIS: This study was conducted to measure the oxygen concentrations in the LAR V and estimate the correlation between oxygen concentration and pre-breathing purges. METHOD: Subjects were 12 males who performed the pre-breathing procedure. The oxygen concentrations in the breathing loop were measured after each purge. RESULTS: The oxygen concentrations depended on the volume of the apparatus dead space, the total capacity of the divers breathing system respective to the volume of the breathing purges and the number of pre-breathing purges. The maximum oxygen concentration was reached after eight purges (O2 = 85%). An equation to estimate the oxygen concentration inside the LAR V and first aid rebreather was derived. CONCLUSIONS: The results indicated that the present purging procedure (three purges) before diving is normally not sufficient to remove the nitrogen totally from the deadspace of the LAR V, the divers airways and lungs. Only a small modification (six purges) is necessary to improve the safety of the diver in case of a diving apparatus malfunction during the mission profile.
Administration, Inhalation↗
Pulmonary barotrauma of a diver using an oxygen rebreathing diving apparatus.
A 22-yr-old healthy male diver performed a dive using a closed circuit oxygen rebreathing apparatus according to normal procedure. After the dive he developed clinical symptoms of mediastinal emphysema. A chest X-ray taken 1 d after the dive showed a discrete "tram track" sign in the left paracardial region. Spiral volumetric computed tomography of the chest 4 d postinjury detected a small subpleural emphysematous bulla next to the left ventricle, the pneumomediastinum being absorbed in the meantime. Clinical outcome of pulmonary decompression barotrauma in the case of oxygen rebreathing may be different from that in compressed air diving, due to the altered gas physics. The necessity for computed tomography of the chest is emphasized, preferably using the spiral mode, in any case of suspected pulmonary barotrauma.
Adult↗
[Diving-associated pulmonary barotrauma as a rare differential diagnosis in internal medicine-pneumologic ambulatory care].
Arterial gas embolism due to pulmonary barotrauma (PBT) is a well known fatal complication in compressed air diving. Pulmonary damage is often missed in conventional diagnostic radiology. We present two cases of PBT in recreational divers, in which pre and post accidental chest x-rays were negative but chest-CT showed peripheral bullae in the lower lung lobes preferably responsible for PBT, Chest-CT is recommended in any case of suspected PBT to evaluate the possibility of preexisting pathology in order to predict further diving fitness.
Adult↗
[Subjective stress factors and dyspnea in asthma patients over time].
The share of psychological factors involved in the disease pattern of asthma bronchiale is considered to be about one to two thirds, according to the literature. It is only rarely that a distinction is made between causative psychogenetic factors and such factors that exercise an influence on the course of the pattern of symptoms. The aim of the present study was to cover prospectively the possible--including the psychological--parameters influencing the pattern of symptoms of asthma in relation to time. To this end a symptom diary was kept for 35 asthma patients for an average time of 8 weeks. The entries were made daily. The points noted and counted were the concurrent occurrence of dyspnoea and various subjective influencing factors such as everyday stress, weather, etc. or their coincidence with a time lag of one day. There were surprisingly few links between dyspnoea and mental stress/stressors in relation to time. On the other hand, there was a high coincidence in relation to impairment of the quality of life and to a lesser extent also in relation to subjectively experienced weather and local conditions. The results show that stress factors--contrary to the aetiological beliefs held by laymen--are not represented by a simple relationship between psyche and asthma as time-concurrent or time-lagging coincidences to shortness of breath. However, clarification of complex socio-psychosomatic linkups in the psychogenesis of asthma bronchiale were not the subject of this study.
Adaptation, Psychological↗
Modification of the closed circuit underwater breathing apparatus LAR V makes it suitable for cardiopulmonary resuscitation (CPR).
UNLABELLED: This pilot study was carried out in order to determine whether or not a modified closed circuit underwater oxygen rebreathing device could serve as an adjunct for ventilation during CPR in remote locations. As a control a common self-inflating bag valve ventilation device was used. METHODS: A total of 20 combat divers were enrolled, of whom 18 met the criteria to be included in two-rescuer CPR manikin training. A modified LAR V (Drager, Germany), a closed circuit underwater breathing apparatus, that uses pure oxygen, and a conventional Ambu Mark III bag were used for artificial mask-ventilation in a randomised crossover design. A total of ten cycles of CPR were analysed. RESULTS: Of the divers, 17 were able to ventilate with the modified LAR V. The median tidal volumes were lower with LAR V versus Ambu (725 vs 800 ml; P = 0.04) and median total time required was significantly longer with LAR V versus Ambu (90 vs 68.5 s; P = 0.004). Gastric inflation was associated only with the Ambu. CONCLUSIONS: This modification of the LAR V makes it suitable for CPR performed by military divers when conventional ventilatory devices are not available. It would be necessary, however, to teach the proper use of the modified ventilation mode and to provide repeated training.
Cardiopulmonary Resuscitation↗