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Hyperbaric Chamber (hyperbaric + chamber)
Selected AbstractsEffects of different exposures of hyperbaric oxygen on ligament healing in ratsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2002Yoshimasa Ishii Hyperbaric oxygen (HBO) is a method of augmenting, intermittently, oxygen availability to tissues. We examined the effect of three different HBO exposures on the healing of experimentally induced ligament lacerations in the right hind limb of 44 male Wistar rats. Animals were divided into four groups after ligament injury: (a) control group, animals breathed room air at 1 ATA (atmosphere absolute) in a hyperbaric chamber for 60 min; (b) HBO treatment at 1.5 ATA for 30 min once a day, (c) HBO treatment at 2 ATA for 30 min once a day, (d) 2 ATA for 60 min once a day. At 14 days post-ligament injury, we compared the ligaments of the four treatment groups for gross appearance, histology and expression of pro-,(I) mRNA by northern hybridization. Our results indicate that HBO was effective in promoting ligament healing compared to control (p < 0.01). Of these three exposures, HBO at 2 ATA for 60 min was the most effective, resulting in enhanced extra-cellular matrix deposition as measured by collagen synthesis. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] MR assessment of changes of tumor in response to hyperbaric oxygen treatment,MAGNETIC RESONANCE IN MEDICINE, Issue 2 2006Ken-ichiro Matsumoto Abstract Enhancement of image intensity, using the T1 -weighted spoiled gradient-echo (SPGR) sequence, was measured in SCC tumor implanted in the flank of C3H mice while they were subjected to several types of oxygenation challenges inside a hyperbaric chamber designed and constructed to fit in an MRI resonator. The central portions of the tumor gave a positive enhancement, while the periphery showed signal reduction during both normobaric (NBO) and hyperbaric (HBO) oxygen challenges. In the contralateral normal leg, nearly 70% of the region showed a decrease in intensity, and the rest showed a positive enhancement. The positive signal enhancement was markedly greater under HBO compared to NBO. Calculated R1, R2, and M0 maps from multivariate fitting of images acquired by a multislice multiecho (MSME) sequence with variable TR before, during, and after HBO treatment confirm that the source of SPGR signal enhancement in the tumor is associated with shortening of T1. Magn Reson Med, 2006. Published 2006 Wiley-Liss, Inc. [source] 3351: Influence of atmospheric pressureand temperature changes on the intraocular pressure.ACTA OPHTHALMOLOGICA, Issue 2010S VAN DE VEIRE Purpose Some patients questioned us whether diving and mountaineering can have an effect on their intraocular pressure (IOP). Since the results in the literature concerning mountaineering are often contradictory and the data concerning diving are very limited; we investigated if an increase in atmospheric pressure influences the IOP in a normal population. Since we clinically experienced higher pressures in the summer, we checked the temperature influence on the IOP simultaneously. Methods Twenty-seven healthy volunteers (aged 18 to 44) were placed in a hyperbaric chamber. Their IOP was measured with a Perkins tonometer at baseline (normal atmospheric pressure of 1 Bar and 24°C), after increasing the atmospheric pressure to 2 Bar both at 14°C and 28°C, and finally at baseline again. A multivariate regression analysis was used to evaluate the results of both eyes. Results The IOP significantly decreased from 11.75mmHg to 10.50mmHg at 2 Bar. The IOP decrease remained constant during the atmospheric pressure rise (40 minutes) and was independent of the temperature change. The IOP returned back to the baseline value when exiting from the hyperbaric chamber. Conclusion A small increase of atmospheric pressure to 2 Bar (= equal effect to diving at 10m below sea level) is sufficient to lead to a significant reduction in IOP independent of temperature changes in a healthy young population. The IOP decrease sustains for the whole hyperbaric chamber period. [source] HYPERBARIC OXYGENATION APPLIED IMMEDIATELY AFTER CORONARY OCCLUSION REDUCES MYOCARDIAL NECROSIS AND ACUTE MORTALITY IN RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2009Leonardo Dos Santos SUMMARY 1Because in ischaemia there is a critical lack of O2, it has been reasoned that increasing O2 delivery to the ischaemic myocardium could serve as adjunctive therapy for acute myocardial infarction (MI). Accordingly, in the present study, the effect of early hyperbaric oxygenation (HBO) on mortality and MI size after coronary occlusion was examined in rats. 2After coronary occlusion, male Wistar rats were randomly assigned to receive either HBO for 1 h in a hyperbaric chamber (100% O2 at 253 kPa; n = 106) or ambient O2 as the control (n = 111). The extent of myocardial necrosis was assessed (triphenyltetrazolium) immediately after treatment in the HBO (n = 50) and control (n = 47) groups. The remaining rats were evaluated 24 h after occlusion to enable calculation of MI size and mortality. 3Immediately after therapy, the size of the MI was significantly greater in the control group compared with that in the HBO group (40 ± 3 vs 27 ± 2% of the left ventricle (LV), respectively; P < 0.001). The 24 h mortality of control rats was higher than that of HBO rats (34 vs 16%, respectively; P = 0.02). Control rats that survived 24 h had a larger MI than did HBO rats that survived 24 h (40 ± 4 vs 29 ± 3% of the LV, respectively; P = 0.005). Furthermore, large necrotic areas (> 40% of the LV) were more frequent in control than HBO rats (55 vs 27% of infarcted hearts, respectively; P = 0.01). There was less pulmonary congestion observed in HBO rats compared with control rats. 4In conclusion, early therapy with HBO during the onset of an acute ischaemic event decreases the necrotic area and reduces acute mortality. These data support further investigation of HBO as an adjuvant therapy for acute MI. [source] Cardiovascular changes induced by cold water immersion during hyperbaric hyperoxic exposureCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2007Alain Boussuges Summary The present study was designed to assess the cardiac changes induced by cold water immersion compared with dry conditions during a prolonged hyperbaric and hyperoxic exposure (ambient pressure between 1·6 and 3 ATA and PiO2 between 1·2 and 2·8 ATA). Ten healthy volunteers were studied during a 6 h compression in a hyperbaric chamber with immersion up to the neck in cold water while wearing wet suits. Results were compared with measurements obtained in dry conditions. Echocardiography and Doppler examinations were performed after 15 min and 5 h. Stroke volume, left atrial and left ventricular (LV) diameters remained unchanged during immersion, whereas they significantly fell during the dry session. As an index of LV contractility, percentage fractional shortening remained unchanged, in contrast to a decrease during dry experiment. Heart rate (HR) significantly decreased after 5 h, although it had not changed during the dry session. The changes in the total arterial compliance were similar during the immersed and dry sessions, with a significant decrease after 5 h. In immersed and dry conditions, cardiac output was unchanged after 15 min but decreased by almost 20% after 5 h. This decrease was related to a decrease in HR during immersion and to a decrease in stroke volume in dry conditions. The hydrostatic pressure exerted by water immersion on the systemic vessels could explain these differences. Indeed, the redistribution of blood volume towards the compliant thoracic bed may conceal a part of hypovolaemia that developed in the course of the session. [source] | ||||||||||