Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Immersion”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources
PubMed2006

Cold-water immersion in a 22-year-old service member.

Cold-water immersion can include aspects of both hypothermia and near drowning. We present a case of a 22-year-old active duty service member who became a victim of cold-water immersion in Alaska. His rescue by the U.S. Coast Guard and subsequent treatment in a small community emergency room are reviewed using a case management format. Care of the cold-water immersion patient with limited resources is highlighted and the potential complications of cold-water immersion are emphasized. Disturbances in acid base balance, pulmonary function, and cardiac rhythm are discussed. Changes in some of the hematological indices seen in the cold-water immersion patient are reported for the first time.

Adult↗
PubMed1998

Heat balance at -5 degrees C after cold water immersion.

Two different possible behaviors at -5 degrees C after cold water immersion were studied. A test subject wearing winter clothing walked (5 km/h) on a treadmill for 45 minutes at -5 degrees C and at a wind velocity of 3 m/s with dry clothing, immediately after a thorough immersion in 5 degrees C water, or after immersion and wringing, freezing, and beating of the clothing (to remove ice). A marked heat debt (ca. 1000 kJ) was measured at the end of the cold water immersion. Attempts to dry the clothing caused an additional heat debt of ca. 300 kJ. After 45 minutes walking, the difference in heat depth between the treatments was nearly the same as before the exercise. The difference in clothing weight was only 0.9 kg between the two treatments after walking. Beating frozen clothing items could remove ice corresponding to only 0.7% of the wet weight of the clothing. Results suggest that after cold water immersion in winter, the undressing procedure could not be recommended. Instead, after initially removing boots, mittens, and hat, the subject should start walking. The water accumulated in boots and mittens should be poured out when necessary.

Adult↗
PubMed1999

The effect of water immersion on postural and visual orientation.

BACKGROUND: The subjective visual vertical (SVV) and the subjective horizontal body position (SHP) perceptually dissociate and may therefore be based on a differential participation of graviceptive references. This study focuses primarily on the effects that are caused by an alteration of somatosensory information on the skin surface induced by water immersion. We expect the SHP to be selectively affected during water immersion while the SVV remains unchanged. METHODS: Four diving subjects took part in the experiments. An underwater apparatus (UWA) allowed for a determination of the SHP and the SVV during water immersion. On land, the adjustments of the SHP and SVV were made in a tilt chair apparatus (TCA). RESULTS: Three of four subjects show a significant head-upward shift between 7 degrees and 20.3 degrees of the SHP when tested under water (p < 0.02). The adjustments of the SVV were compared within corresponding physical roll inclinations and did not differ with the exception of one subject who showed a significant change of the SVV toward the physical vertical. CONCLUSIONS: The SHP and SVV perceptually dissociate on land and, as we determined for the first time, also under water. Water immersion leads to an increased roll tilt perception as measured by the SHP. However, a systematic influence on SVV could not be observed under water thus supporting the assumption that the SVV and SHP depend on gravitoreceptive information that is selectively altered during water immersion.

Adult↗
PubMed1997

Effects of three days of dry immersion on heart rate and blood pressure variabilities during head-up tilting in humans.

In this study we examined the effects of 3 days of dry immersion on heart rate variability (HRV) and blood pressure variability (BPV) in response to head-up tilting in 4 healthy young subjects aged 21 to 36 years. Resting value of the high-frequency (HF) power of BPV and HRV decreased, while the low-frequency (LF)/HF ratio of HRV and blood pressure increased after the dry immersion. The HF power of HRV decreased, while the LF/HF ratio of HRV and heart rate increased during head-up tilting before and after dry immersion. All powers of BPV and BP were unchanged during head-up tilting. The values of the decrease in the HF power of HRV and the increase in the LF/HF ratio during head-up tilting after dry immersion were larger than those before. These results suggest that 3 days of dry immersion altered the autonomic balance toward the sympathetic dominant at rest, and that cardiac function may play a crucial role in BP maintenance during head-up tilting compared with vasoconstrictor function.

Adult↗
PubMed2000

[Multiple organ dysfunction syndrome after open chest wound and seawater immersion: experimental study].

OBJECTIVE: To evaluate the effect of seawater immersion on multiple organ dysfunction syndrome (MODS) after chest trauma. METHODS: Twenty health dogs were divided into two groups. Right open pneumothorax was induced in both control group (n = 10) and experimental group (n = 10). After induction of chest trauma, animals in the experimental group were immersed in artificial seawater. Blood samples were taken at seven different intervals for assessing blood gas, plasma level of TNFalpha, and IL-1 beta. Changes of serum alanine aminotransferase (ALT), aspartate amino-transferase (AST), creatine kinase (CK) lactate dehydrogenase (LDH) and creatinine (Cr) were measured. At the end of study, lung was harvested for assessing lung water content and ratio of wet weight and dry weight. RESULTS: A significant elevation of ALT, AST, CK and LDH was observed in both groups. Organ functional parameters in the experimental group were consistent with the failure standard at 30 minutes after seawater immersion, and those in the control group at 4 hours. Post-trauma mortality and incidence of MODS were much higher in the experimental group than those in the control group (P < 0.01). The plasma levels of TNFalpha and IL-1 beta significantly increased at 30 minutes and reached the highest level at 60 minutes after seawater immersion. The time of peak level appeared earlier in the experimental group than that in the control group. CONCLUSION: Seawater immersion after open chest trauma results in high incidence of MODS and high mortality rate due to progressive dysfunction of multiple organs.

Animals↗
PubMed2001

[Phase structure of the ejection period in the human cardiac function before and after 3-day water immersion].

Impedance cardiography was applied to 15 normal male volunteers before and after 3-d water immersion. Determined were parameters of central circulation and dependence of the ejection period on length of the cardiac cycle. Though the ejection period over the whole range of cardiac cycle lengths was shorter than "due" values determined as pre-immersion baseline, cardiac output after immersion was equal to and even slightly above baseline value. According to experimental results, this seems to be linked with little if any dependence of the fast ejection phase, hemodynamically most effective, on heart rate and volume loading which remained same as in the baseline period during all post-immersion tests. In contrast, the reduced ejection period, a variable of the ventricular blood evacuation, is materially dependent on heart rate and volume loading predetermining at large absolute and relative shortening of the ejection period after immersion.

Circadian Rhythm↗
PubMed2002

"DRY" immersion induces neural and contractile adaptations in the human triceps surae muscle.

The effects of 7-days of simulated spaceflight, achieved with the technique of "dry" water immersion, on human triceps surae muscle function have been investigated in six subjects. After immersion, the maximal voluntary contraction (MVC) was reduced by 19% (p<0.01), and the electrically evoked (150 Hz) maximal tetanic contraction (Po) was reduced by 8% (p>0.05). The difference between Po and MVC expressed as a percentage of Po and referred to as force deficiency has also been calculated. The force deficiency increased by 44% (p<0.01) after immersion. The decrease in Po was associated with increased maximal rates of tension development (7.2%) and of tension relaxation. The twitch time-to-peak was not significantly changed, and half relaxation and total contraction time were decreased by 5% and 3%, respectively, but the twitch tension (Pt) was not significantly changed and the Pt/Po ratio was decreased by 9%. The 60-s intermittent contractions (50 Hz) decreased tetanic force to 57% (p<0.05) of initial values, but force reduction was not significantly different in the two fatigue tests: fatigue index was 36.2 +/- 5.4% vs. 38.6 +/- 2.8%, respectively (p>0.05). While identical force reduction was present in the two fatigue test it would appear that concomitant electrical failure was considerably different. Comparison of the electrical and mechanical responses alterations recorded during voluntary contractions, and in contractions evoked by electrical stimulation of the motor nerve, suggests that immersion not only modifies the peripheral processes associated with contraction, but also changes central and/or neural command of the contraction. At peripheral sites, it is proposed that the intracellular processes of contraction play a role in the contractile impairment recorded during immersion.

Adaptation, Physiological↗
PubMedDate not supplied

[Blood plasma volume dynamics in monkeys during immersion].

Dynamics of blood plasma volume (PV) was studied with indirect methods (hematocrit count, hemoglobin, total protein and high-molecular protein) during 9-d immersion of monkeys Macaca mulatta. The animals were donned in waterproof suits, motor restrained in space seat liners and immersed down to the xiphisternum. Two monkeys were immersed in the bath at one time. The suits were changed every day under ketamine (10 mg/kg of body mass). There were two groups with 12 animals in each. The first group was kept in the bath 3 days and the second--9 days. Prior to the experiment, the animals had been trained to stay in the seat liner put down into the dry bath. It was shown that already two days of exposure to the hydrostatic forces (approximately 15 mm Hg) and absence of negative pressure breathing reduced PV by 18-20% on the average in all animals. Subsequent PV dynamics was individual by character; however, PV deficit persisted during 4 days of immersion in the whole group. In this period, albumin filtration was increased significantly, whereas high-molecular protein filtration was increased to a less degree. During the remaining days in immersion PV regained normal values. Ten days of readaptation (reclined positioning of monkeys brought back into cage) raised VP beyond baseline values. This phenomenon can be attributed to the necessity to provide appropriate venous return and sufficient blood supply of organs and tissues following extension of blood vessels capacity.

Albumins↗
PubMed2004

Is water immersion useful for analyzing gravity resistance responses in terrestrial plants?

Water immersion has been used as a simulator of microgravity for analyzing gravity responses in semiaquatic plants such as rice. To examine whether or not water immersion for a short experimental period is a useful microgravity simulator even in terrestrial plants, we analyzed effects of water immersion on the cell wall rigidity and metabolisms of its constituents in azuki bean epicotyls. The cell wall rigidity of epicotyls grown underwater was significantly lower than that in the control. Water immersion also caused a decrease in molecular mass of xyloglucans as well as the thinning of the cell wall. Such changes in the mechanical and chemical properties of the cell wall underwater were similar to those observed in microgravity conditions in space. These results suggest that water immersion for a short period is a useful system for analyzing gravity resistance responses even in terrestrial plants.

Cell Wall↗
PubMedDate not supplied

[The effect of immersion in distilled water on the engorged larvae and nymphs of Amblyomma dubitatum Neumann, 1899 (Acari: Ixodidae)].

To evaluate the effect of the immersion of engorged larvae and nymphs of Amblyomma dubitatum experimentally fed on rabbits, the ticks were collected and formed control groups, without immersion, and groups witch were immersed by 24, 48, 72, 96 hours and, for engorged larvaes, by eight weeks, in test tubes containing distilled water. During all experiment ticks were kept at 27 +/- 1 degrees C, 80 +/- 10% RU and scotophase The parameters evaluated were: pre-ecdysis, ecdysis and moulting periods; and ecdysis and mortality percentages. When compared with the control group, the effect (p<0,05) of immersion varied intra and inter stages. Apparently, immersion was less deleterious to A. dubitatum in comparison with A. cajennense and R. sanguineus from neotropical region, thus reflecting a long host relations with the capybara, its primary host.

Animals↗
PubMed2006

[Survival in cold water. Physiological consequences of accidental immersion in cold water].

This survey addresses the immediate physiological reactions to immersion in cold water: cold shock response, diving reflex, cardiac arrhythmias and hypothermia. Cold shock response is the initial sympathetic reaction to immersion in cold water. The diving reflex is elicited by submersion of the face. Afferent and efferent nerves are the trigeminal and vagal nerves. Cardiac arrhythmias occur immediately after immersion. If the immersion persists, hypothermia becomes an issue. Hypothermia is delayed by habituation to immersion in cold water as well as insulating garments, subcutaneous fat and a large lean body mass.

Accidents↗
PubMed1991

Physiological responses of the human extremities to cold water immersion.

Five subjects immersed their hands and feet twice during 1 hour sessions in a calorimeter bath, filled with water at 25 degrees C. Before immersion the hand (33.0 +/- 2.2 degrees C) was warmer than the foot (30.6 +/- 2.1 degrees C) and so was the blood flow: respectively 5.8 +/- 5.2 versus 0.7 +/- 0.3 ml.min-1.100 mo tissue-1 as determined by strain gauge plethysmography and 10.8 +/- 5.1 versus 6.7 +/- 5.3 by the doppler method. At the end of the immersion period the blood flow had decreased a factor of 2.9 (doppler) and 4.3 (plethysmography). The local heat transfer, determined by heat flux transducers, was highest immediately after immersion. The maximum was higher at the ventral sides than at the dorsal sides of the hand (225 +/- 93 versus 186 +/- 61 W.m-2 and the foot (178 +/- 53 versus 160 +/- 57 W.m-2). The total heat transferred to the water by hand or foot during the 60 minutes of immersion, determined by calorimetry, was 47 +/- 21 and 36 +/- 36 kJ respectively and was not statistically different due to considerable interindividual differences. Interindividual differences were also found for heat flux, rectal and local skin temperature and blood flow. These differences will have to be taken into account if a comparison is made with data from subjects with local cold injuries.

Adolescent↗
PubMed1990

A comparison of bed rest and immersion for treating the edema of pregnancy.

Bed rest and immersion both lead to a mobilization of extravascular fluid and thus reduce edema. This study compared three treatments for edema in healthy pregnant women in the third trimester: lateral supine bed rest at room temperature, sitting in a bathtub of waist-deep water at 32 +/- 0.5C with legs horizontal, and sitting immersed in shoulder-deep water at 32 +/- 0.5C with legs extended downward. Post-treatment diuresis was selected as the indicator of extravascular fluid mobilization. The mean (+/- SD) diuresis was 105 +/- 48, 161 +/- 155, or 242 +/- 161 mL/hour for bed rest, bathtub, and immersion tank, respectively (P less than .008, tank versus bed rest; P less than .05, tank versus bath). In all treatments, mean arterial pressure (MAP) declined from a baseline value of 88 +/- 9 to 77 +/- 10 mmHg 25 minutes into treatment and 77 +/- 11 mmHg at 50 minutes (both P less than .0001 compared with pre-treatment). Shoulder-deep immersion produced the greatest decline in MAP. Sodium clearance increased from 0.7 to 1.0 mEq/minute in all treatments (P less than .01). Serum sodium, potassium, creatinine, osmolarity, total protein, 6-keto prostaglandin F1 alpha, and plasma volume did not change significantly after the treatments. Serum prolactin declined significantly from 137.8 +/- 44 to 124 +/- 31 ng/mL after treatment; there was no difference among treatments. Immersion appears to be a safe and more rapid method than bed rest to mobilize extravascular fluid during pregnancy.

Adult↗
PubMed1986

A simple method for estimation of gastric mucus and effects of antiulcerogenic agents on the decrease in mucus during water-immersion stress in rats.

In the present study Corne's technique that has been commonly used to quantify the gastric mucus in situ using the dye, Alcian blue, has been improved. Furthermore, the effects of antiulcerogenic agents on the decrease in gastric mucus gel during water-immersion stress were also studied. In order to increase the extraction of dye-recovery, we used 30% dioctyl sodium sulfosuccinate (docusate sodium, DSS) instead of 0.5 mol/l MgCl2 used in Corne's technique. The control values of the dye-recovery extracted with DSS were about 5 times higher than those with MgCl2. Indomethacin (20 mg/kg s.c.) failed to influence dye-recovery with DSS and MgCl2, while reserpine (5 mg/kg i.p.) significantly decreased the dye-recovery in both extractions. Water-immersion stress for 2 h decreased the dye-recovery with DSS but the dye-recovery with MgCl2 decreased only 15 min after water-immersion. These results suggest that extraction with DSS reflects the mucus gel secretion, and that dye-recovery with DSS is more sensitive to alteration of mucus gel than that with MgCl2. Bombesin (10 micrograms/kg), secretin (100 U/kg) and mild irritants increased the dye-recovery with DSS. Cimetidine remarkably reduced the mucus secretion and failed to improve the decrease in mucus during water-immersion stress. Pirenzepine and atropine dose-dependently prevented the decrease in the dye-recovery during water-immersion stress.

Alcian Blue↗
PubMed1986

Increases in circulating atrial natriuretic factor during immersion-induced central hypervolaemia in normal humans.

The role of atrial natriuretic factor (ANF) in modulating volume and circulatory homeostasis remains uncertain, and there has been as yet no systematic analysis of the factors promoting ANF release in humans. Since immersion in water to the neck provides a 'volume stimulus' identical to that induced by 2 litres of saline, without plasma compositional change, immersion to the neck was used to assess the ANF response to acute central blood-volume expansion. Using a radio-immunoassay that reliably detected ANF in human plasma extracts, more than 80% of plasma immunoreactive (ir) ANF was shown to elute as a single peak on reverse-phase high performance liquid chromatography, with a retention time identical to that of the synthetic 28-residue alpha-human (alpha-h) ANF. The response of plasma irANF to 3 h of immersion in water to the neck was evaluated in four sodium-replete normal subjects; the immersion produced a prompt and marked increase in irANF in each subject, and recovery was associated with a prompt return to pre-study levels. Concurrently, there was a marked natriuresis and a profound suppression of plasma renin and aldosterone. These findings support the hypothesis that an increase in plasma ANF contributes to the hormonal and renal effects of immersion in water to the neck, suggesting that ANF has an important physiological role in modulating volume homeostasis in humans.

Adult↗
PubMed1988

Hyperresponsiveness to water immersion in sodium retaining cirrhotics: the role of atrial natriuretic factor.

Cirrhotics do not respond uniformly to head-out water immersion (HWI). Some cirrhotics have an exaggerated natriuresis while others are unresponsive. We studied the humoral and urinary responses to HWI in 5 cirrhotics and compared this to 5 normals on the same 20 mM sodium intake. These cirrhotics had a documented tendency to salt and water retention but had minimal or no evidence of significant ascites. Plasma levels of atrial natriuretic factor (ANF) increased during immersion in both groups. However, the rise in plasma ANF from baseline during each hour of immersion was significantly greater in the cirrhotics (p less than 0.01), than in the normal volunteers. In these cirrhotics, HWI not only corrected the pre-immersion tendency to sodium retention, but by 3 hours had produced an exaggerated natriuretic response (p less than 0.05). It is possible that the greater risk of ANF in cirrhotics is responsible for this natriuretic response. However the reason for the larger rise in cirrhotics is unclear; presumably either a greater central redistribution of plasma volume occurs in cirrhotics following immersion, or there may be greater sensitivity of the ANF release system in cirrhotics.

Aldosterone↗
PubMed1988

The effects of cold immersion and hand protection on grip strength.

The maximal voluntary grip strength (MVGS) of male volunteers was examined following a series of five intermittent 2 min cold water (5 degrees C) immersions of the unprotected hand or forearm. MVGS changes due to wearing a protective glove were also investigated. The surface electrical activity over the hand flexor muscles was recorded, as was the skin temperature of the hand and forearm. MVGS decreased significantly (p less than 0.01) following hand immersions (16%) and forearm immersion (13%). The majority of these reductions occurred during the first 2-min period of immersion. The effect of wearing a glove after unprotected hand cooling also produced significant (p less than 0.01) MVGS reductions which averaged 14%. These reductions were in addition to those caused by hand cooling. We conclude that both hand and forearm protection are important for the maintenance of hand-grip strength following cold water immersion.

Adult↗
PubMed1987

Plasma volume and endocrine responses to water immersion with intermittent positive-pressure breathing in men.

The effect of intermittent positive-pressure breathing (PB), induced by expiring against a resistance of 12.5 mm Hg, on plasma volume and endocrine responses to standing water immersion, was studied in seven male subjects, 28-49 years of age. The men were immersed to the neck (35 +/- 0.5 degrees C) for 90 min with PB from 30 to 60 min. Compared to control values, the hematocrit and hemoglobin concentration decreased (p less than 0.001) during immersion while plasma osmolality was unchanged, indicating an isotonic increase in plasma volume (hemodilution) which peaked after 75 min at +15.5% of the preimmersion plasma volume. This hemodilution was not significantly affected by PB. Plasma renin activity and vasopressin and aldosterone concentrations decreased progressively throughout immersion (p less than 0.001) and were unaffected by PB. The magnitude of these hormonal decreases was accentuated by preexisting, presyncopal symptoms in four subjects. It is concluded that intermittent PB as 12.5 mm Hg failed to compensate for the negative-pressure breathing of standing subjects immersed in water to the neck.

Adult↗