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PubMed2000

Effects of reduced salinity on survival, growth, reproductive success, and energetics of the euryhaline polychaete Capitella sp. I.

Physiological adjustment to water of reduced salinity requires energy expenditure. In this study we sought to determine the fitness costs associated with such adjustment in the euryhaline polychaete Capitella sp. I, and the extent to which such costs could be explained by increased rates of energy expenditure. In a series of experiments conducted at 20 degrees C, salinity was reduced from 30 per thousand to either 25, 20, 15, 12, or 10 per thousand within 72 h after the larvae had been induced to metamorphose. Juveniles were reared on fine, organic-rich sediment. Over the next 15-30 days, we determined survival, growth, fecundity, and rates of respiration and feeding (via fecal pellet production). Larval salinity tolerance was also determined. Juvenile survival at salinities as low as 12-15 per thousand was comparable to that at 30 per thousand. The lower limit of salinity tolerance was 10-12 per thousand at 20 degrees C for both larvae and juveniles. Juveniles grew significantly more slowly at 12-15 per thousand in six of the seven experiments. Fecundity, however, was generally highest at intermediate salinities of 20-25 per thousand, and comparable at 30 and 15 per thousand. No individuals released embryos at 12 per thousand over the approximately 30-day observation periods in any of the three experiments in which the worms were reared at this low salinity. Reduced growth rates were not explained by differences in rates of respiration at different salinities: at reduced salinity, respiration rates were either statistically equivalent to (P>0.10) or significantly below (P<0.05) those recorded for animals maintained at 30 per thousand. Lower growth rates at lower salinities were best explained by reduced feeding rates. Further studies are required to determine whether digestive efficiency, growth hormone concentrations, or reproductive hormone concentrations are also altered by low salinity in this species.

Journal Article↗

PubMed2001

Biological perchlorate reduction in high-salinity solutions.

Perchlorate (ClO4-) has been detected in numerous ground and surface waters, and has recently been added to the drinking water Candidate Contaminant List in the United States. Perchlorate can be removed from drinking water using ion exchange, but this results in the production of highly saline (7-12%) perchlorate-contaminated brines. Perchlorate-degrading microbial enrichments capable of growth in highly saline water were obtained by screening six salt water environments including marine and lake surface waters, salt marshes, subtidal sediments, and a biofilm/sludge from a seawater filter. Perchlorate reduction was obtained in three of these samples (seawater, saline lake water, and biofilm/sludge) at a salinity of 3%. The salinity range of two of these cultures was extended through serial transfers into media having higher salt concentrations (3-7%). Growth rates were measured over a salinity range of 1-15%. The maximum growth rate measured for the saline lake-water enrichment was 0.060+/-0.003 d(-1) (doubling time of 11.6+/-0.8 d) at a salinity of 5%. Growth rates decreased to 0.037+/-0.002 d(-1) at a salinity of 11%, and no growth was observed at salinities of 13 or 15%. These results demonstrate for the first time that biological perchlorate reduction is possible in solutions having a salinity typical of ion exchange brines.

Biodegradation, Environmental↗

PubMed2003

The toxicity of metal mixtures to the estuarine mysid Neomysis integer (Crustacea: Mysidacea) under changing salinity.

Water quality criteria are mainly based on data obtained in toxicity tests with single toxicants. Several authors have demonstrated that this approach may be inadequate as the joint action of the chemicals is not taken into account. In this study, the combined effects of six metals on the European estuarine mysid Neomysis integer (Leach, 1814) were examined. Acute 96-h toxicity tests were performed with mercury, copper, cadmium, nickel, zinc and lead, and this as single compounds and as a mixture of all six. The concentrations of the individual metals of the equitoxic mixtures were calculated using the concentration-addition model. The 96-h LC50's for the single metals, at a salinity of 5 per thousand, ranged from 6.9 to 1140 microg/l, with the following toxicity ranking: Hg>Cd>Cu>Zn>Ni>Pb. Increasing the salinity from 5 to 25 per thousand resulted in lower toxicity and lower concentrations of the free ion (as derived from speciation calculations) for all metals. This salinity effect was strongest for cadmium and lead and could be attributed to complexation with chloride ions. The toxicity of nickel, copper and zinc was affected to a smaller extent by salinity. The 96-h LC50 for mercury was the same for both salinities. In order to evaluate the influence of changing salinity conditions on the acute toxicity of metal mixtures, tests were performed at different salinities (5, 10, 15 and 25 per thousand ). The 96-h LC50 value (1.49 T.U.) of the metal mixture, at a salinity of 5 per thousand, was clearly lower than the expected value (6 T.U.) based on the non-additive hypothesis, thus confirming the additive effect of these metals in the marine/estuarine environment. Changing salinity had a profound effect on the toxicity of the mixture. The toxicity clearly decreased with increasing salinity until 15 per thousand. Higher salinities (25 per thousand ) had no further influence on the 96-h LC50 of the mixture which is situated at a value between 4.4 and 4.6. Finally, the relative sensitivity to the selected metals was compared with the relative sensitivity of the commonly used mysid Americamysis (=Mysidopsis) bahia.

Animals↗

PubMed2003

The effects of rapid salinity change on in vivo arginine kinase flux in the juvenile blue crab, Callinectes sapidus.

The effect of acclimation salinity and salinity changes on the concentration of high-energy phosphate metabolites and arginine kinase (AK) flux was examined in vivo in juvenile blue crabs using 31P-nuclear magnetic resonance (NMR). Crabs were acclimated for 7 days to a salinity of 5 or 35 per thousand and then placed in a flow apparatus that could sustain the animals while NMR spectra were acquired. Crabs were subjected to either hyperosmotic salinity changes, where an animal acclimated to 5 per thousand was exposed to a salinity of 35 per thousand, or hyposmotic changes, which involved the reciprocal exchange. Neither acclimation salinity nor salinity change had a significant effect on the concentrations of arginine phosphate, inorganic phosphate or ATP. 31P-NMR saturation transfer experiments were used to determine the effect of salinity on the forward and reverse flux of the AK reaction. There was no significant effect of acclimation salinity or salinity change on the flux rate through this reaction. This is in contrast to previous results, which showed that AK flux in isolated muscle was sensitive to prevailing osmotic conditions (Holt and Kinsey, J. Exp. Biol. 205 (2002) 1775-1785). The present study indicates that the integrated osmoregulatory capacity of the intact animal is sufficient to preserve cellular energy status and enzyme function during acute salinity changes.

Acclimatization↗

PubMed1997

The effect of epidural saline injection on analgesic level during combined spinal and epidural anesthesia assessed clinically and myelographically.

UNLABELLED: An epidural injection of physiological saline solution after spinal anesthesia may produce a higher level of analgesia than spinal anesthesia alone because of a volume effect. The purpose of this study was to clarify the volume effect caused by epidural injection of saline after spinal anesthesia. Twenty patients undergoing combined spinal and epidural anesthesia for elective surgery whose analgesic levels did not reach the surgical regions 10 min after spinal anesthesia at the L4-5 interspace were randomly assigned to two groups. The control group (n = 10) received no epidural saline injection. The saline group (n = 10) received 10 mL of saline through an epidural catheter at the L2-3 or L3-4 interspace 10 min after spinal anesthesia. In the saline group, the levels of analgesia 15 and 20 min after spinal anesthesia were significantly higher than those in the control group (P < 0.05). Next, we examined the volume effect of epidural injection of saline with myelography using two adult volunteers. In both volunteers, the upper level of the contrast medium, which was injected in the lumbar subarachnoid space, began to increase concurrently with lumbar epidural injection of saline, reaching from L3 to L1 and from L2 to T12. The diameter of the subarachnoid space diminished to less than 25% after injection of saline. We conclude that lumbar epidural injection of saline increases the analgesic level 10 min after spinal anesthesia, probably because of a volume effect. IMPLICATIONS: In this study, using surgical patients and volunteers, we determined that a lumbar epidural injection of physiological saline solution 10 min after spinal anesthesia produces a higher analgesic level than spinal anesthesia alone because of a volume effect.

Adult↗

PubMed2005

Effects of epidural saline injection on cerebrospinal fluid volume and velocity waveform: a magnetic resonance imaging study.

BACKGROUND: The phenomenon of epidural "top-up" (increased spread of local anesthetic due to epidural fluid injection) is explained partly by an epidural volume effect. This study was designed to investigate the change in cerebrospinal fluid (CSF) volume and velocity waveform induced by epidural saline injection. METHODS: (1) Lumbar epidural catheters were placed in 28 patients. Magnetic resonance images were obtained for measurements of lumbosacral CSF volume and velocity waveform. Saline was injected into the epidural space through the catheter to three groups of randomly assigned patients: 5-ml saline (n = 10), 10-ml saline (n = 9), and 15-ml saline (n = 9) groups. A repeat image series was performed after epidural injection to compare CSF volume and velocity waveform before and after epidural injection. (2) We also examined the time course of dural sac compression after epidural saline injection in a separate series. Seven axial images at disk levels from T11-T12 to L5-S1 were obtained before injection and 1, 3, 5, 10, 15, 20, 25, and 30 min after 10-ml saline injection to compare each dural area before and after injection. RESULTS: (1) Saline injected through the epidural catheter compressed the dural sac with variability of the extent of compression, resulting in a significantly decreased CSF volume in all patients (P <== 0.001). The mean reductions in CSF volume were 2.0 +/- 1.0 ml in the 5-ml group, 4.4 +/- 1.4 in the 10-ml group, and 7.2 +/- 2.6 in the 15-ml group. There were significant differences among the three groups (P < 0.05 approximately 0.001). After the saline injection, the synchronization between the CSF velocity waveform and the cardiac cycle disappeared in significantly more patients in the 10-ml group (7 of 9 patients) than in the other groups (P < 0.05). However, there was no significant relation between measures of CSF velocity waveform and dural area in any patient. (2) The maximum reduction of the sum of the total of seven disk areas occurred 5 min after epidural saline injection; thereafter, dural compression was gradually restored but did not return to the value before injection for 30 min. CONCLUSIONS: These findings indicate that the reduction in CSF volume was injection-volume dependent, dural compression lasted at least 30 min after saline injection, and the changes of the CSF flow dynamics did not correlate with the degree of dural sac compression.

Adult↗

PubMed2002

Minimizing diaphragmatic injury during radio-frequency ablation: efficacy of subphrenic peritoneal saline injection in a porcine model.

PURPOSE: To investigate if a targeted subphrenic peritoneal infusion of normal saline to separate liver from diaphragm before radio-frequency (RF) ablation could minimize or eliminate diaphragmatic injury. MATERIALS AND METHODS: With a 2-cm-diameter, eight-prong RF needle electrode, 37 hepatic dome RF lesions were created in 10 pigs. Seventeen lesions were created before (non-saline group) and 20 lesions after (post-saline group) intraperitoneal infusion of approximately 500 mL of normal saline. Ten non-saline lesions were created deep (centered 1-2 cm from the liver surface) and seven superficially (centered within 1 cm of the capsule). All 20 post-saline lesions were created superficially. Helical enhanced computed tomography was performed 24-48 hours after ablation. The pigs were killed immediately, and the diaphragm was visually inspected and sectioned. Diaphragmatic injury was graded as 0, no injury; 1, injury up to one-third thickness; 2, injury to two-thirds thickness; 3, full-thickness injury. Representative grade 3 injuries and all partial injuries underwent gross and histologic analysis. RESULTS: All 10 deep non-saline RF lesions caused grade 0 injury. All seven superficial non-saline lesions caused grade 3 injury. Of the 20 superficial post-saline lesions, 13 (65%) caused grade 0 injury; four (20%), grade 1; and three (15%), grade 3. The post-saline group caused significantly less diaphragmatic injury (P <.05). CONCLUSION: Intraperitoneal saline infusion may reduce the frequency and severity of diaphragmatic injury when adjacent liver is treated with RF ablation.

Animals↗

PubMedDate not supplied

Pressor hyperresponsiveness in saline-infused rabbits.

Conscious rabbits infused intravenously (i.v.) with isotonic saline at 1.5 to 1.8 ml/min for 24 hours had greater pressor responses to norepinephrine (NE) than did normal control rabbits. Infusion of the angiotension II (ANG II) antagonist [Sar1, Ile8] ANG II did not decrease the exaggerated pressor responses to NE in saline-infused rabbits. Measurements of cardiac output (CO) as well as the pressor responses to NE before and after saline infusion revealed that, although saline infusion increased the CO and decreased total peripheral resistance (TPR), CO did not change during NE infusion either before or after saline infusion, but NE produced significantly greater increases in mean arterial pressure (MAP) and TPR after saline infusion than before the saline infusion. The cross-circulation of blood at 10 ml/min for 5 minutes between saline-infused donor rabbits and normal recipient rabbits resulted in pressor hyperresponsiveness to NE in the normal recipients. Similar cross-circulation experiments between pairs of normal rabbits did not alter the pressor responses to NE. These studies provided direct evidence that expansion of body fluid volumes by saline infusion results in pressor and vascular hyperresponsiveness. There was no evidence to indicate that ANG II was involved in the mechanisms producing this pressor hyperresponsiveness. Some circulating hormonal factor, however, was involved in mediating the pressor hyperresponsiveness following saline infusion. The results of this study are compatible with the concept that natriuretic hormone may play a role in promoting pressor hyperresponsiveness in saline-expanded animals.

Angiotensin II↗

PubMed2004

Differences in the effects of salinity on larval growth and developmental programs of a freshwater and a euryhaline mosquito species (Insecta: Diptera, Culicidae).

The effects of salinity on growth and development of the euryhaline Ochlerotatus taeniorhynchus and the freshwater Aedes aegypti are compared. O. taeniorhynchus grow larger, and have greater intrinsic growth rates, than A. aegypti. Females of each species attain greater mass, take longer to develop, and have greater growth rates than do males. In O. taeniorhynchus, pupal mass, larval stage duration and growth rates (dry mass) increase with salinity, whereas growth rates (wet mass) remain constant across salinities, reflecting a decrease in percent body water. The pupal mass (wet or dry) of O. taeniorhynchus is determined primarily by effects of salinity on the rate of assimilation of dry mass, because the latter contributes very strongly to final pupal mass in both species. In contrast, the duration of A. aegypti larval stage follows a upsilon-shaped curve, with most rapid development at intermediate salinities. Growth rates of A. aegypti decrease with increasing salinity, and percent body water is constant across salinities. As for O. taeniorhynchus, duration of A. aegypti larval stage increases at high salinity. However, this increase in larval stage duration cannot compensate for the decrease in growth rate at high salinity, resulting in an overall decrease in both wet and dry pupal mass at high salinity. Thus, salinity has fundamentally different effects on developmental programs and phenotypic plasticity in the two species investigated.

Aedes↗

PubMed2006

Sub-lethal and chronic salinity tolerances of three freshwater insects: Cloeon sp. and Centroptilum sp. (Ephemeroptera: Baetidae) and Chironomus sp. (Diptera: Chironomidae).

Increased salinity in rivers and streams is a serious environmental concern, and in Australia there is growing information about the acute tolerances to salinity for freshwater macroinvertebrates, but much less information about chronic and sub-lethal tolerances. The effects of increased salinity on the growth and survival of two mayflies, Cloeon sp. and Centroptilum sp. and one midge Chironomus sp. are reported. In both mayfly species survival was variable. Complete mortality was observed in salinities with electrical conductivity of 10 mS cm(-1) and higher. Salinities causing chronic mortality in mayflies were measured as 21-day LC50, and ranged from 0.90 to 2.7 mS cm(-1). Growth rates were not significantly different between treatments. In Chironomus, salinity affected the mean number emerging as flying adults as well as the time to emergence. An inverted 'U' shape response was observed for percentage emergence, with the greatest numbers emerging at intermediate salinities (0.65-5.0 mS cm(-1)). No emergence occurred at salinities of 20 mS cm(-1) and higher. Time to emergence was delayed by 15-88% with increased salinity, however the size of emerged adults was the same for all treatments. Growth rates were reduced with increased salinity, showing a slow, steady reduction up to 10 mS cm(-1) then a steep decline between 10 and 15 mS cm(-1). The implications of altered growth rates and changes in developmental times are discussed. This study illustrates the variability in responses to increased salinity, and highlights the need to continue studying sub-lethal and chronic exposures in a range of freshwater invertebrates, in order to predict impacts of salinisation on freshwater biodiversity.

Animals↗

PubMed1998

Effect of cyclical salinity changes on cell volume and function in geukensia demissa gills

We acclimated the estuarine mussel Geukensia demissa to a regime of sinusoidal salinity cycling (12 h cycle between 100 % and 60 % seawater) and correlated changes in the volume of gill cells with changes in several indicators of the functional status of gill cells (rate of O2 consumption, ATP content and amino acid transport). There was no indication of short-term volume regulation in the gill cells of mussels acclimated to salinity cycling. When exposed to cycling salinity, cell water space consistently increased to approximately 3 ml g-1 dry mass during the cycle troughs (60 % seawater) and returned to approximately 2 ml g-1 dry mass at the cycle peaks (100 % seawater). In mussels acclimated for 2 weeks to cycling salinity, the gill contents of betaine, taurine and K+ were unchanged (approximately 240, 230 and 160 micromol g-1 dry mass, respectively) between the 60 % and 100 % seawater portions of the salinity cycle. The changes in cell volume did not appear to be associated with large perturbations in the functional status of cells. The rate of O2 consumption was approximately 100 microl O2 g-1 dry mass min-1, and ATP content was approximately 30 micromol g-1 protein, in all salinities to which mussels were exposed. Rates of uptake of taurine, leucine and phenylalanine decreased by approximately 50 % during the first sinusoidal decrease to 60 % seawater, but recovered following re-exposure to 100 % seawater. Uptake rates of all three amino acids were unaffected by any subsequent salinity cycles. These results suggest (1) that the regulation of gill cell volume is normally absent from mussels exposed to repeated, gradual salinity changes, and (2) that any effects of changes in cell volume are not severe enough to justify the energetic expenditure that would be associated with repeated regulation of cell volume. Unlike the response of gill cells to cycling salinity, there was a decrease in the solute contents of ventricles during the salinity troughs compared with the salinity peaks, suggesting that the presence of short-term volume regulation may be more critical in the ventricle.

Journal Article↗

PubMed2003

Influence of salinity on the bioaccumulation and photoinduced toxicity of fluoranthene to an estuarine shrimp and oligochaete.

The effect of salinity on the photoinduced toxicity of waterborne fluoranthene to larvae of the grass shrimp (Palaemonetes pugio) and tubificid oligochaete worms (Monopylephorus rubroniveus) was studied in a laboratory system under simulated sunlight. In the grass shrimp toxicity tests, five concentrations of fluoranthene (0, 3.6, 7.3, 13.8, and 29.0 microg/L) and four salinities (6.9, 14.5, 21.2, and 28.6 per thousand) were achieved. In the oligochaete toxicity tests, five concentrations of fluoranthene (0, 0.8, 1.4, 3.3, and 7.7 microg/L) and four salinities (7.1, 13.3, 20.5, and 27.6 per thousand) were achieved. Salinity had no effect on either the photoinduced toxicity or the bioaccumulation of fluoranthene in the grass shrimp. However, the highest level of salinity decreased the median lethal time for the oligochaete. Bioaccumulation of fluoranthene was inversely related to salinity for the oligochaete. Additional experiments demonstrated an inverse relationship between salinity and short-term osmotic weight change in the oligochaete. Weight of the grass shrimp larvae was not affected by salinity. These findings show that salinity can influence the toxicity and bioaccumulation of fluoranthene in some estuarine organisms. The influence of salinity on these populations may be related to physiological responses associated with internal osmotic volume changes. Thus, salinity needs to be taken into account when assessing the risk of photoactivated polycyclic aromatic hydrocarbon (PAH) to at least some estuarine species.

Animals↗

PubMed1999

Salinity as a constraint on growth of oligohaline marsh macrophytes. II. Salt pulses and recovery potential.

The ability of common oligohaline marsh macrophytes of the northern Gulf of Mexico coast to recover from pulses of increased salinity was investigated in a greenhouse experiment with Eleocharis palustris, Panicum hemitomon, Sagittaria lancifolia, and Scirpus americanus monocultures. Components of salinity pulses applied were final salinity reached (6 or 12 g/L), salinity influx rate (3 d or 3 wk), and duration of exposure (1, 2, or 3 mo). After each exposure period, we placed plants into freshwater until the end of the 120-d experiment to determine recovery potential. The four species varied in their ability to recover from the salinity pulses. Within a species, recovery varied with final salinity level and duration of exposure, and to a lesser extent with salinity influx rate. Scirpus americanus, growth of which was stimulated by <3 mo of exposure to 6 g/L, was able to recover even under the most extreme conditions of exposure to 12 g/L salinity for 3 mo. Ability to recover decreased with increased salinity and increased duration of exposure for the remaining three species. Recovery of specific aspects of growth was also suppressed in these species by a rapid salinity influx rate compared to a slow influx rate. The complex variations in recovery patterns displayed by the different species may lead to changes in species dominance following the short-term salinity pulses that can occur during storm events, which in turn may affect marsh plant community composition and structure.

Journal Article↗

PubMed2001

The effect of salinity on different developmental stages of an endemic annual plant, Aster laurentianus (Asteraceae).

Salinity reduces substrate water potential, thereby restricting water and nutrient uptake by plants; salinity may also cause ionic imbalance and toxicity. Because substrate salinity fluctuates through the growing season, a plant may be exposed to different salinity levels, at various stages of development, with potentially significant consequences on population dynamics. Here, we present the results of a study of the effect of substrate salinity on seed germination, seedling emergence, and growth of Aster laurentianus, an annual marsh plant, endemic to the Gulf of St. Lawrence and potentially threatened. Seed germination was reduced in low salt concentration (10 g sea salt/L) and completely inhibited by salinity levels >/=20 g sea salt/L. However, this inhibiting effect was reversible: seeds from the salt treatments germinated readily after being washed in distilled water. Though seedling emergence was diminished at low salinity levels, postemergence survival was little affected. Plant growth was reduced, but net carbon assimilation rate was not affected by high salinity levels. Increased root respiration and respiratory costs associated with salt tolerance might have contributed to lower C accumulation at higher salinity levels. All developmental processes considered are thus negatively affected by substrate salinity, with potentially significant consequences on population abundance and distribution in salt marshes. Yet, the tolerance of this species to high salinity levels after seedling emergence is remarkable. Seed germination represents a major bottleneck in the species life cycle, potentially controlling local distribution and abundance in the natural habitat.

Journal Article↗

PubMedDate not supplied

A comparison of excimer laser (308 nm) ablation of the human lens nucleus in air and saline with a fiber optic delivery system.

BACKGROUND: Photoablation with excimer lasers has demonstrated precise tissue cutting and minimal thermal damage. Potential ophthalmic applications of these lasers include remodelling of the corneal surface, glaucoma treatment, and phacoablation. Ablation of human lens with a 308 nm XeCl excimer laser light delivered through a fiber has been demonstrated in preliminary experiments. Intraocular delivery of laser light must be done in a fluid medium to preserve the integrity of ocular structures. However, little information is available on the effect of the fluid media on the ablation process. Therefore, a series of experiments was conducted to determine whether the ablation of human lens nucleus at 308 nm via a fiber differs in air and saline media. METHODS: Ablation of human lens nuclei (n = 30) was conducted with a XeCI excimer laser (308 nm) coupled to a 600 microns core size fiber. Irradiation was performed at 2.8 mJ/cm2 energy density and 20 Hz. The fiberoptic was brought to contact with the lens nucleus and remained fixed for the duration of irradiation. Variables consisted of the medium (air or saline) and number of pulses delivered (100 to 10,000). Following establishment of the tissue shrinkage ratio, the depth of each crater and the tissue volume removed were measured histologically. The histological features of nucleus ablation in air and in saline were also examined with both light and scanning electron microscopy. RESULTS: Light microscopy revealed that the average zone of thermal damage adjacent to the crater is thinner in the presence of saline (60 microns, SD = 6 microns) than it is in air (90 microns, SD = 12 microns). In both media, the thickness of the zone of thermal damage is greater at the surface than it is at its base. Following irradiation in air, deep sharpedged craters with smooth walls are formed. Craters formed by irradiation in saline are characterized by reduced depth and irregular walls. For the same number of pulses applied (500, 1000, and 2000), the mean depth of ablation per pulse in air (8.6 to 2.7 microns/pulse) was greater by approximately a factor of two than that in saline (4.10 to 1.30 microns/pulse) at P < .01. However, the mean ablated volume removed per pulse was greater in saline (0.00250 to 0.00150 mm3/pulse) than in air (0.00120 to 0.00080 mm3/pulse), for the same number of pulses (1000, 2000) at P < .01. CONCLUSIONS: In comparing the data for the same number of pulses applied in air and in saline, it appears that the depth of crater formed by irradiation in air is deeper than that in fluid. The overall volume ablated is greater in fluid than it is in air at 1000 and 2000 pulses. Additionally, the zone of thermal damage is thinner in the presence of saline than it is in air. Smoother crater shapes were observed following irradiation in air than in saline. These results suggest that under this specific experimental setup, the ablation in saline is different from that in air.

Aged↗

PubMed2005

Cold saline injection attenuates motor-evoked potential in the spinal cord by cortical electrical stimulation in the dog.

Changes in the motor-evoked potential of the spinal cord with transcranial stimulation are monitored for spinal cord function during thoracoabdominal aortic aneurysm surgeries. We examined the effects of changes in motor-evoked potential with cold saline injected into the clamped segment of the aorta, and compared the effects to lidocaine and warm saline injection. Eighteen dogs were divided into three groups according to the injected agents: Warm saline group (37 degrees C, 20 ml), Cold saline group (4 degrees C, 20 ml), and Lidocaine group (5.0 mg/kg of lidocaine in 20 ml of warm saline), (n=6, each group). Changes in the peak-to-peak MEP amplitude and the indirect wave (I wave) amplitude were measured during aortic cross-clamping. In the peak-to-peak MEP amplitude, the cold saline and lidocaine groups attenuated to 80% of the control value but were not significantly changed. In the I wave amplitude, the cold saline group showed a significant attenuation 1 min after injection (p<0.0001) and the lidocaine group 4 min after injection (p=0.0230), when compared with the warm saline group. Attenuation of the I wave amplitude in the cold saline group was significantly larger than that in the lidocaine group (p=0.0003). Changes in the I wave amplitude appeared within 4 min in both the cold saline and lidocaine groups. Cold saline injection into the clamped segment of the aorta is a diagnostic procedure for determining presiding critical arteries in the segment without experiencing the pharmacological side effects observed with lidocaine injection.

Animals↗

PubMed1998

A survey of endotracheal suctioning with instillation of normal saline.

BACKGROUND: Instillation of normal saline before suctioning is a common nursing intervention although little research supports the practice. OBJECTIVES: To determine when and how often saline is used during suctioning and to assess the knowledge of nurses and respiratory therapists of the advantages and dangers of using saline during endotracheal suctioning. METHODS: A survey of nurses and respiratory therapists working in adult ICUs was conducted in a large university teaching hospital. RESULTS: Of the 187 respondents, 96 (51%) rarely instill saline before suctioning, whereas 61 (33%) frequently use saline. Fifty-five percent use saline to enhance retrieval of secretions, and 45% use it to stimulate a cough. Nurses and respiratory therapists differ in their use and understanding of saline instillation. Most nurses (64%) rarely use saline before suctioning, whereas most respiratory therapists (71%) frequently use saline. Respiratory therapists (57%) were more aware than were nurses (37%) of the benefit of using normal saline to stimulate a cough. Nurses indicated more adverse effects of instillation of normal saline, specifically oxygen desaturation and increased risk of pulmonary infections, than did respiratory therapists. CONCLUSION: The results of the survey helped determine target areas for educational programs for nurses and respiratory therapists. A protocol is being developed for use by all who do suctioning.

Adult↗

PubMed2005

Nebulised hypertonic saline for cystic fibrosis.

BACKGROUND: Lung disease in cystic fibrosis is characterised by impaired mucociliary clearance. Hypertonic saline has been shown to enhance mucociliary clearance in vitro and this may act to lessen the destructive inflammatory process in the airways. OBJECTIVES: To investigate the effects of treatment with nebulised hypertonic saline on people with cystic fibrosis compared to placebo and or other treatments that enhance mucociliary clearance. SEARCH STRATEGY: 'We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Most recent search of the Trials Register: September 2004. SELECTION CRITERIA: All controlled trials assessing the effect of hypertonic saline compared to placebo or other mucolytic therapy, for any duration or dose regimen in people with cystic fibrosis of any age or severity. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed all identified trials and all data collected. Trial quality was assessed along with allocation concealment. MAIN RESULTS: Fourteen controlled trials were identified. Nine trials met the inclusion criteria involving 235 participants with an age range of 6 years to 46 years. Two short-term trials of immediate effect on mucociliary clearance demonstrated that hypertonic saline increased isotope clearance compared to control. Lung function, measured by improvement in forced expiratory volume at one second (FEV1 litre per minute), was observed in four trials. When 3% to 7% saline was used in a volume of 10 ml twice-a-day, in comparison to placebo, hypertonic saline led to a significant increase in FEV1, weighted mean difference 12.20 (95%CI 4.28 to 20.10). Two further trials compared a similar concentration and volume of hypertonic saline to recombinant deoxyribonuclease. Over a three-week period one trial showed a non-significant difference, mean difference 1.60 (95% CI -7.96 to 11.16). However, in a further trial, after 12 weeks treatment in participants with moderate to severe lung disease, recombinant deoxyribonuclease led to a greater increase in FEV1 than hypertonic saline (5 ml twice-daily), mean difference 8.00 (95%CI 2.00 to 14.00). No serious adverse events were noted. AUTHORS' CONCLUSIONS: Nebulised hypertonic saline improves mucociliary clearance in short-term clinical trials and appears to increase lung function compared to control. In comparison to recombinant deoxyribonuclease it may be less effective at improving lung function after three months. Currently there is insufficient evidence to support the use of hypertonic saline as routine treatment for people with cystic fibrosis.

Administration, Inhalation↗