Home About us Contact
|
Home About us Contact | ||
|
|
||
Fluid Shifts (fluid + shift)
Selected AbstractsSIMULATED MICROGRAVITY [BED REST] HAS LITTLE INFLUENCE ON TASTE, ODOR OR TRIGEMINAL SENSITIVITYJOURNAL OF SENSORY STUDIES, Issue 1 2001ZATA M. VICKERS ABSTRACT Anecdotal evidence suggests that astronauts' perceptions of foods in space flight may differ from their perceptions of the same foods on Earth. Fluid shifts toward the head experienced in space may alter the astronauts' sensitivity to odors and tastes, producing altered perceptions. Our objective was to determine whether head-down bed rest, which produces similar fluid shifts, would produce changes in sensitivity to taste, odor or trigeminal sensations. Six subjects were tested three times prior to bed rest, three times during bed rest and two times after bed rest to determine their threshold sensitivity to the odors isoamylbutyrate and menthone, the tastants sucrose, sodium chloride, citric acid, quinine and monosodium glutamate, and to capsaicin. Thresholds were measured using a modified staircase procedure. Self-reported congestion was also recorded at each test time. Thresholds for monosodium glutamate where slightly higher during bed rest. None of the other thresholds were altered by bed rest. [source] Fluid shifts during cardiopulmonary bypass with special reference to the effects of hypothermiaBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2000J. K. Heltne Background Generalized overhydration, oedema and organ dysfunction occurs in patients undergoing open heart surgery using cardiopulmonary bypass (CPB) and hypothermia. Inflammatory reactions induced by contact between blood and the foreign surfaces of the extracorporeal circuit are commonly held responsible for the disturbances in fluid balance (,capillary leak syndrome'). Using the CPB circuit reservoir as a fluid gauge (measuring continuous extracorporeal blood volume), fluid shifts between the intravascular and the extravascular space, and differences between normothermic and moderately hypothermic CPB, were examined. Methods Piglets were placed on CPB (thoracotomy) under general anaesthesia. In the normothermic group (n = 7) the core temperature was kept at 38°C before and during 2 h on CPB, whereas in the hypothermic group (n = 7) the temperature was lowered to 29°C during bypass. In addition to accurate recording of fluid during operation, the extracorporeal blood volume was kept constant by maintaining a certain blood level in the CPB circuit's reservoir. Acetated Ringer was used as priming solution in the CPB, as maintenance fluid and for adding fluid to the reservoir if necessary. Results Cardiac output, serum electrolytes and arterial blood gases were all similar in the two groups. Haematocrit fell significantly following the start of CPB in both groups. The reservoir fluid level fell markedly in both groups necessitating fluid supplementation. This extra fluid requirement was transient in the normothermic group, but persisted in hypothermic animals. At the end of 2 h of CPB the hypothermic animals had received seven times more extra fluid than the normothermic pigs. Conclusion There were strong indications of a greater fluid extravasation induced by hypothermia. The model described, using the PBC circuit reservoir as a fluid gauge, provides the opportunity for further study of fluid volume shifts, their causes and potential ways to manipulate fluid pathophysiology related to hypothermia and to PBC. © 2000 British Journal of Surgery Society Ltd [source] Estimation of Acute Fluid Shifts Using Bioelectrical Impedance Analysis in HorsesJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2007C. Langdon Fielding Background: Multi-frequency bioelectrical impedance analysis (MF-BIA) has been used to evaluate extracellular fluid volume (ECFV), but not fluid fluxes associated with fluid or furosemide administration in horses. If able to detect acute changes in ECFV, MF-BIA would be useful in monitoring fluid therapy in horses. Hypothesis: The purpose of this study was to evaluate the ability of MF-BIA to detect acute fluid compartment changes in horses. We hypothesized that MF-BIA would detect clinically relevant (10,20%) changes in ECFV. Animals: Six healthy mares were used in the study. Methods: This is an original experimental study. Mares were studied in 3 experiments: (1) crystalloid expansion of normally hydrated subjects, (2) furosemide-induced dehydration followed by crystalloid administration, and (3) acute blood loss followed by readministration of lost blood. MF-BIA measurements were made before, during, and after each fluid shift and compared to known changes in volume calculated based on the intravenous fluids that were administered in addition to urinary fluid losses. Mean errors between MF-BIA estimated change and known volume change were compared using nonparametric analysis of variance. Estimated ECFV pre- and post-fluid administration similarly were compared. The level of statistical significance was set at P < .05. Results: Results of the study revealed a statistically significant change in ECFV and total body water during crystalloid expansion and dehydration. Statistically significant changes were not observed during blood loss and administration. Mean errors between MF-BIA results and measured net changes were small. Conclusions and Clinical Importance: MF-BIA represents a practical and accurate means of assessing acute fluid changes during dehydration and expansion of ECFV using isotonic crystalloids with potential clinical applications in equine critical care. [source] Effects of immersion water temperature on whole-body fluid distribution in humansACTA PHYSIOLOGICA, Issue 1 2004J. M. Stocks Abstract Aim:, In this study, we quantified acute changes in the intracellular and extracellular fluid compartments during upright neutral- and cold-water immersion. We hypothesized that, during short-term cold immersion, fluid shifts would be wholly restricted to the extracellular space. Methods:, Seven males were immersed 30 days apart: control (33.3 ° SD 0.6 °C); and cold (18.1 ° SD 0.3 °C). Posture was controlled for 4 h prior to a 60-min seated immersion. Results:, Significant reductions in terminal oesophageal (36.9 ° ± 0.1 °,36.3 ° ± 0.1 °C) and mean skin temperatures (30.3 ° ± 0.3 °,23.0 ° ± 0.3 °C) were observed during the cold, but not the control immersion. Both immersions elicited a reduction in intracellular fluid [20.17 ± 6.02 mL kg,1 (control) vs. 22.72 ± 9.90 mL kg,1], while total body water (TBW) remained stable. However, significant plasma volume (PV) divergence was apparent between the trials at 60 min [12.5 ± 1.0% (control) vs. 6.1 ± 3.1%; P < 0.05], along with a significant haemodilution in the control state (P < 0.05). Plasma atrial natriuretic peptide concentration increased from 18.0 ± 1.6 to 58.7 ± 15.1 ng L,1 (P < 0.05) during cold immersion, consistent with its role in PV regulation. We observed that, regardless of the direction of the PV change, both upright immersions elicited reductions in intracellular fluid. Conclusion:, These observations have two implications. First, one cannot assume that PV changes reflect those of the entire extracellular compartment. Second, since immersion also increases interstitial fluid pressure, fluid leaving the interstitium must have been rapidly replaced by intracellular water. [source] Lactoferrin and anti-lactoferrin antibodies: Effects of ironloading of lactoferrin on albumin extravasation in different tissues in ratsACTA PHYSIOLOGICA, Issue 1 2000Erga Lactoferrin is a cationic iron-binding protein, which is released from activated neutrophils in concert with reactive oxygen species. In vitro, lactoferrin has both anti- and proinflammatory effects; many of them dependent on iron-binding. In vivo, only iron-free lactoferrin reduced inflammatory hyperpermeability in the lung. We therefore examined whether 1 mg iron-free (Apo-Lf) or iron-saturated lactoferrin (Holo-Lf) alone or followed by anti-lactoferrin antibodies (aLf) affected permeability evaluated by extravasation of radiolabelled bovine serum albumin (CBSA) in different tissues of anaesthetized rats. Fifteen minutes after i.v. injection of Lf, aLf or saline was given and circulatory arrest was induced 20 min thereafter. Measurements were performed in control, after Apo-Lf, Holo-Lf, Apo-Lf + aLf, Holo-Lf + aLf and aLf alone (n=6,8 in each group). No intergroup differences were found for plasma volume and haematocrit at the start and end of the 37 min extravasation period or for total tissue water in any of the six different tissues studied, excluding larger transcapillary fluid shifts. However, increases in CBSA were seen without differences in tissue intravascular volume. Iron-free lactoferrin and aLf alone did not change CBSA significantly. Iron-saturated lactoferrin significantly increased CBSA in skin (neck), trachea and left ventricle of the heart to 249 ± 9, 284 ± 16 and 160 ± 7% of control, respectively. When followed by aLf, both Apo- and Holo-Lf increased CBSA significantly in four and five of the tissues studied, respectively. However, no significant effect was seen for Holo-Lf + aLf compared with Holo-Lf alone. In conclusion, iron-saturated, but not iron-free lactoferrin increased CBSA, whereas antilactoferrin increased CBSA compared with lactoferrin alone only when following iron-free lactoferrin. [source] Calcium Channel Blocker-Related Peripheral Edema: Can It Be Resolved?JOURNAL OF CLINICAL HYPERTENSION, Issue 4 2003Domenic A. Sica MD Calcium channel blocker (CCB)-related edema is quite common in clinical practice and can effectively deter a clinician from continued prescription of these drugs. Its etiology relates to a decrease in arteriolar resistance that goes unmatched in the venous circulation. This disproportionate change in resistance increases hydrostatic pressures in the precapillary circulation and permits fluid shifts into the interstitial compartment. CCB-related edema is more common in women and relates to upright posture, age, and the choice and dose of the CCB. Once present it can be slow to resolve without intervention. A number of strategies exist to treat CCB-related edema, including switching CCB classes, reducing the dosage, and/or adding a known venodilator such as a nitrate, an angiotensin-converting enzyme inhibitor, or an angiotensin-receptor blocker to the treatment regimen. Angiotensin-converting enzyme inhibitors have been best studied in this regard. Diuretics may alter the edema state somewhat, but at the expense of further reducing plasma volume. Traditional measures such as limiting the amount of time that a patient is upright and/or considering use of graduated compression stockings are useful adjunctive therapies. Discontinuing the CCB and switching to an alternative antihypertensive therapy will resolve the edema. [source] SIMULATED MICROGRAVITY [BED REST] HAS LITTLE INFLUENCE ON TASTE, ODOR OR TRIGEMINAL SENSITIVITYJOURNAL OF SENSORY STUDIES, Issue 1 2001ZATA M. VICKERS ABSTRACT Anecdotal evidence suggests that astronauts' perceptions of foods in space flight may differ from their perceptions of the same foods on Earth. Fluid shifts toward the head experienced in space may alter the astronauts' sensitivity to odors and tastes, producing altered perceptions. Our objective was to determine whether head-down bed rest, which produces similar fluid shifts, would produce changes in sensitivity to taste, odor or trigeminal sensations. Six subjects were tested three times prior to bed rest, three times during bed rest and two times after bed rest to determine their threshold sensitivity to the odors isoamylbutyrate and menthone, the tastants sucrose, sodium chloride, citric acid, quinine and monosodium glutamate, and to capsaicin. Thresholds were measured using a modified staircase procedure. Self-reported congestion was also recorded at each test time. Thresholds for monosodium glutamate where slightly higher during bed rest. None of the other thresholds were altered by bed rest. [source] Fluid shifts during cardiopulmonary bypass with special reference to the effects of hypothermiaBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2000J. K. Heltne Background Generalized overhydration, oedema and organ dysfunction occurs in patients undergoing open heart surgery using cardiopulmonary bypass (CPB) and hypothermia. Inflammatory reactions induced by contact between blood and the foreign surfaces of the extracorporeal circuit are commonly held responsible for the disturbances in fluid balance (,capillary leak syndrome'). Using the CPB circuit reservoir as a fluid gauge (measuring continuous extracorporeal blood volume), fluid shifts between the intravascular and the extravascular space, and differences between normothermic and moderately hypothermic CPB, were examined. Methods Piglets were placed on CPB (thoracotomy) under general anaesthesia. In the normothermic group (n = 7) the core temperature was kept at 38°C before and during 2 h on CPB, whereas in the hypothermic group (n = 7) the temperature was lowered to 29°C during bypass. In addition to accurate recording of fluid during operation, the extracorporeal blood volume was kept constant by maintaining a certain blood level in the CPB circuit's reservoir. Acetated Ringer was used as priming solution in the CPB, as maintenance fluid and for adding fluid to the reservoir if necessary. Results Cardiac output, serum electrolytes and arterial blood gases were all similar in the two groups. Haematocrit fell significantly following the start of CPB in both groups. The reservoir fluid level fell markedly in both groups necessitating fluid supplementation. This extra fluid requirement was transient in the normothermic group, but persisted in hypothermic animals. At the end of 2 h of CPB the hypothermic animals had received seven times more extra fluid than the normothermic pigs. Conclusion There were strong indications of a greater fluid extravasation induced by hypothermia. The model described, using the PBC circuit reservoir as a fluid gauge, provides the opportunity for further study of fluid volume shifts, their causes and potential ways to manipulate fluid pathophysiology related to hypothermia and to PBC. © 2000 British Journal of Surgery Society Ltd [source] | ||||||||||