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Query: UMLS:C0042571 (vertigo)
 7,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sudden incapacitations can affect a pilot and even a whole crew during a flight, preventing them from performing their task in complete safety. In some cases, they could even cause an accident. Our study examines the causes of sudden in-flight incapacitation in Air France pilots and flight engineers from 1968-88. Ten cases were reported out of a population of 1,800 cockpit crew, each flying an average of 600 h/year. These incapacitations were due to cardiac disorders (1 atrial fibrillation, 1 sinus tachycardia), epileptic attacks (2 generalized seizures), duodenal hemorrhages (2 cases), infection (1 case of severe vertigo due to viral labyrinthitis), metabolic disorders (1 case of hypoglycemia), and sometimes disorders affecting the whole crew (1 case of hypoxia due to a pressurization deficiency, 1 case of CO2 intoxication caused by the inadequate packaging of a container refrigerated in dry ice). Seven times out of ten, incapacitations occurred during cruising, twice during approach, and once on the ground before starting up, with closed doors (CO2 intoxication). Two of these incapacitations led to flight diversions. None of them caused an accident. In this series, incapacitations of a cardiac nature were rarer and less serious than those caused by gastrointestinal or neurological disorders. Prevention is based on detection during systematic medical check-ups, and on crews being trained to recognize subtle incapacitations early and to ensure that the flight continues safely when such a case occurs.
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PMID:Clinical aspects of inflight incapacitations in commercial aviation. 231 81

Stimulated by positive reports of patients who were treated with CO2-gas injections during a sanatorium stay in the CSSR and after evaluation of the literature, we began with the CO2-gas injection in our patients in 1983. The following disturbances and groups of diseases were included as indication to this form of therapy: 1. Cervico-cranial syndrome, in particular pains in the neck, contractions of the neck, headache including migraine and vertigo 2. Cervico-brachial syndrome 3. Lumbalgia with and without root-irritation syndrome 4. Other pain conditions at the apparatus of locomotion (by degenerative changes, muscular contractions and others). Before the beginning of the therapy the diagnoses were clinically and paraclinically clarified. The therapeutic mechanism is explained by the physiological irritation, which is evoked by the high CO2-concentrations in the tissue and leads to an increase of the blood supply in the adequate region. The results of the therapy are convincing.
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PMID:[CO2 gas injection--indications and results]. 312 16

Vertigo related to acidosis in Meniere's disease has been reported. This study was undertaken to ascertain whether acidosis has any effect on vertigo. Since patients with Meniere's disease usually show unilateral vestibular dysfunction, unilateral intratympanic injection of streptomycin sulfate (SM) was used to induce unilateral vestibular dysfunction in rabbits. Intratympanic SM injections induced vestibular destruction and elicited severe spontaneous nystagmus and ataxia. Then symptoms of acute vestibular upset gradually subsided and eventually disappeared completely. Three weeks after SM injections, in compensated rabbits, NH4Cl injection or CO2 inhalation was used to induce acidosis. Intravenous NH4Cl injection or CO2 inhalation induced nystagmus and ataxia again. In normal rabbits, no nystagmus was induced by NH4Cl injection or by CO2 inhalation. These results suggest that acidosis might be a cause of recurrence of vertigo in patients with unilateral vestibular dysfunction.
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PMID:Effect of experimental acidosis on nystagmus in rabbits. 820 92

We investigated the influence of unilateral VA occlusion on blood regulation in the brainstem and the inner ear, using laser-Doppler flowmetry in rat. Chemical control was evaluated by blood flow response to CO2 inhalation, and autoregulation by that to induced hypotension. The results were as follows: i) Unilateral VA occlusion impairs chemical control and autoregulation of brainstem blood flow and affects autoregulation in the inner ear. ii) Unilateral VA occlusion damages the potential for blood flow regulation more strongly in the brainstem than in the inner ear. These results suggest that occlusive disease within the vertebro-basilar system leads to the impairment of blood flow regulation in both the brainstem and the inner ear-more strongly in the brainstem-possibly contributing to symptoms such as vertigo and hearing disturbance, at least in certain groups of patients when hemodynamic factors such as systemic hypotension are added.
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PMID:The influence of unilateral vertebral artery occlusion on brainstem and inner ear blood flow in rat. 874 94

The purpose of this study was to compare the effectiveness of mechanical and laser-assisted posterior semicircular canal occlusion (PCO) for the treatment of intractable benign paroxysmal positional vertigo (BPPV). Twelve consecutive patients with intractable BPPV underwent PCO by three surgeons, six with mechanical PCO and six with CO2 laser-assisted PCO. PCO eliminated positional vertigo in all patients treated with the laser and five of six patients treated without the laser. Dysequilibrium was present in all patients immediately postoperatively. This resolved in all patients treated with the CO2 laser but in only two of six patients treated without the laser (p = 0.03). Patients were hospitalized for dysequilibrium for an average of 5.2 and 2.8 days for the mechanical and laser-assisted groups, respectively. Preoperative and postoperative hearing was not significantly different between the groups. No clinically significant postoperative hearing loss was encountered in either group. These results suggest that PCO is an effective treatment for intractable BPPV. The incidence of dysequilibrium that persists following PCO may be reduced by using the CO2 laser to seal the membranous canal prior to occluding the bony canal.
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PMID:Mechanical versus CO2 laser occlusion of the posterior semicircular canal in humans. 881 19

1. The aim of this study was to investigate the analgesic effect and its duration of a new sustained-release preparation of tramadol in an experimental pain model based on pain-related chemosomatosensory evoked potentials (CSSEPs) and subjective intensity estimates of painful phasic and tonic stimuli. 2. Twenty volunteers participated in a randomised, double-blind, three-fold cross-over study. Measurements were obtained before and 0.5, 1, 4, 6, and 12 h after administration of the drug (100 mg, 200 mg and placebo orally). CSSEPs were recorded after stimulation of one nostril with phasic, painful CO2 pulses. The other nostril was stimulated with a constant stream of dry air, which produced a tonic painful sensation. Subjects rated the perceived intensity of phasic and tonic stimuli via visual analogue scales. In order to test for nonspecific effects, acoustic evoked potentials (AEPs) were recorded, the spontaneous EEG was analysed in the frequency domain, the subject's vigilance was assessed in a tracking task, and the side effects of the drug were monitored. 3. The sustained-release preparation of tramadol produced a significant dose-related decrease in CSSEP amplitudes when compared with placebo. The reduction in amplitudes outlasted the observation period of 12 h, demonstrating the prolonged duration of the analgesic effect. 4. A dose-related significant decrease could be observed for the estimates of tonic pain. Similar to the decrease of amplitudes of the CSSEP, the reduction of the ratings of tonic pain outlasted the observation period of 12 h. The observed slight decrease in the estimates of phasic pain under medication did not reach a statistically significant level when compared with placebo. No significant effect could be demonstrated for the perception of the phasic and the tonic pain as determined by the McGill-Questionnaire. 5. A significant dose-related increase in the estimates of the side effects 'drowsiness', 'vertigo' and 'sickness' but not for 'tiredness' could be demonstrated.
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PMID:Dose dependent time course of the analgesic effect of a sustained-release preparation of tramadol on experimental phasic and tonic pain. 883 37

Sudden hearing loss is an entity of unknown cause. Different theories of its etiology and treatment have been proposed. The objective of our report is to evaluate the efficacy of the therapeutic protocol used in our department in patients with sudden hearing loss. We made a retrospective study of 24 patients who had experienced sudden hearing loss from January 1994 to March 1998. We studied the parameters of age, sex, days of hospitalization, vestibular symptoms, otoscopy, personal history, radiology study, and successive audiograms. The treatment protocol consists of low-dose steroids, pentoxyphylline, and carbogen, and a concentration of 5% CO2 and 95% O2. Treatment was effective, with a recovery rate of 83%. The factors of tinnitus or vertigo, the state of hearing in the opposite ear, and age did not influence the recovery of hearing. However, the form of the audiogram and initial hearing were important prognostic factors.
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PMID:[Sudden deafness: efficacy of a therapeutic protocol]. 1114 84

The aim of this study was to audit the introduction of the use of the CO2 laser into our department and to compare hearing outcomes and complication rates in patients who underwent either laser or mechanical stapedectomy. We found that the use of laser is at least as safe as the traditional approach with regards the rate of post-operative complications. One patient in the laser group suffered prolonged post-operative tinnitus, whilst one patient in the traditional group suffered prolonged post-operative vertigo. There was no evidence, however, of improved Air-Bone Gap closure compared to the traditional approach (Pre- and Post-Op Air Bone Gaps of 34 +/- 3 and 9 +/- 2 for laser stapedectomy versus 35 +/- 4 and 13 +/- 2 for traditional stapedectomy (mean +/- SEM)). In summary, therefore, CO2 laser surgery for otosclerosis is a safe surgical procedure resulting in similar hearing outcomes to that obtained following mechanical stapes surgery.
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PMID:A comparison of CO2 laser versus traditional stapedectomy outcomes. 1977 3

Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax), sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea) an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient.Instead of the hypoxia altitude simulation test (HAST), which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil) or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists) including mechanical aids to reduce periodical or insufficient ventilation during altitude exposure (added dead space, continuous or bilevel positive airway pressure, non-invasive ventilation) call for further randomized controlled trials of combined applications.
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PMID:Fit for high altitude: are hypoxic challenge tests useful? 2295 73

The aims of this study were to examine selected respiratory and gasometric parameters during hyperventilation with and without isocapnia and to identify the possible mechanism by which isocapnic hyperventilation might be useful in the elimination of volatile substances, including CO. Ten healthy non-smoking volunteers were studied, and each underwent two procedures. During one session, CO2 was added to the respiratory circuit, and during the other session, only 100% O2 was used. The volunteers were coached to hyperventilate until the appearance of side effects. Isocapnic hyperventilation significantly increased alveolar minute ventilation and partial pressure of oxygen in arterialized capillary blood (paO2); to the best of our knowledge, these findings have not previously been reported. Isocapnic hyperventilation was associated with only mild side effects, such as dyspnea, increased respiratory effort and headache, in 30% of subjects. Side effects, including vertigo, paresthesias and muscle tremor, were present in 70% of the volunteers during hyperventilation with 100% O2, and these side effects forced them to limit their respiratory rates and tidal volumes. These increases in alveolar ventilation and the partial pressure of oxygen in the blood may play crucial roles in decreasing the half-time of carboxyhemoglobin, which is the primary goal of the treatment of CO poisoning.
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PMID:Hyperventilation with and without maintenance of isocapnia: a comparison of selected gasometric and respiratory parameters. 2502 Feb 13


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