***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Successful resuscitation of the injured may be achieved more rapidly and with less fluid using hypertonic crystalloid solutions than with isotonic solutions . This r and omized , double-blind study compared 0.9 % normal saline ( NS ) to 1.8 % hypertonic saline ( HS ) in 20 postoperative coronary artery bypass patients suffering uniform injury . Study solutions were administered to maintain physiologic endpoints : heart rate , blood pressure , and pulmonary capillary wedge pressure . The groups were similar with respect to age , body surface area , operative procedure , intraoperative fluid status , and intraoperative and postoperative red cell transfusion requirements . HS patients required 30 % less fluid than NS patients and were in negative fluid balance during the study ( -1,715 + /- 732 ml/24 hr , HS , vs. + 266 + /- 825 ml/24 hr , NS ; p less than 0.01 ) . In contrast , NS patients were in positive fluid balance after 8 hours . Moreover , HS patients experienced less chest tube drainage than NS patients ( 981 + /- 88 ml , HS , vs. 1,700 + /- 285 ml , NS ; p less than 0.01 ) . Systemic and pulmonary hemodynamic measurements , oxygen delivery , oxygen consumption , and shunt fraction did not differ between the two groups . Serum sodium and osmolality increased in the HS group and peaked at 12 hours ( 145.4 + /- 1.4 mEq/L and 308.7 + /- 2.0 mOsm/kg , respectively ) and correlated with the volume of HS infused ( correlation coefficient = 0.81 ) . No deaths occurred and no complication was attributed the hypertonicity of the solution . We conclude that 1.8 % hypertonic saline is a safe alternative to isotonic crystalloid therapy in the fluid management of postoperative patients . Decreased third-space losses may occur with HS as suggested by the lower thoracic losses in the HS group ; 1.8 % NaCl may be the preferred solution in situations where excess free water administration is not desired , and where interstitial edema is detrimental to function and /or survival Background : Previous studies found hypertonicity to affect immune responses in intact laboratory animals and in human blood cell cultures . In this study , the authors investigated the cellular immune response to surgery after preoperative infusion of hypertonic saline in humans . Methods : Sixty-two women scheduled to undergo abdominal hysterectomy were r and omly assigned to single-blinded infusion of 4 ml/kg NaCl , 7.5 % ; 4 ml/kg NaCl , 0.9 % ; or 32 ml/kg NaCl , 0.9 % , over 20 min . Blood was collected at baseline , during surgery , and 1 , 24 , and 48 h after surgery for the determination of leukocyte and differential counts , flow cytometric phenotyping of mononuclear cells , and natural killer cell activity against K 562 tumor cells . Phytohemagglutinin-induced lymphocyte proliferation , plasma elastase , and neutrophil chemotaxis were measured at the same time points except during surgery . The authors tested cell-mediated immune function in vivo by delayed-type hypersensitivity reaction in the skin . Results : Surgery induced well-known changes in the cellular immune response , which were unrelated to the tonicity or volume of the infused fluids . Conclusion : Infusion of a clinical ly relevant dose of hypertonic saline did not seem to modify the postoperative cellular immune response after elective abdominal hysterectomy OBJECTIVE To compare the effects of 7.5 % hypertonic saline ( HS ) and 0.9 % normal saline ( NS ) on perioperative weight gain in cardiac surgical patients . DESIGN Prospect i ve , r and omized study . SETTING University teaching hospital . PARTICIPANTS Patients ( n = 72 ) scheduled for elective coronary artery bypass graft surgery . INTERVENTIONS Patients were r and omly assigned to receive either 7.5 % HS ( 36 patients ) or 0.9 % NS ( 36 patients ) as a single dose of 4 mL/kg over 30 minutes during the postoperative rewarming phase in the intensive care unit . MEASUREMENTS AND MAIN RESULTS Weight gain until the first postoperative morning was significantly greater in the NS group than in the HS group ( 1.9 plus minus 1.4 kg , median , 2.1 kg ; 0.8 plus minus 1.5 kg , median , 0.8 kg ; p = 0.005 ) . One-hour diuresis after the fluid infusion was significantly greater in the HS group compared with the NS group ( 501 plus minus 282 mL and 237 plus minus 173 mL ; p < 0.001 ) . In the linear regression model , the 2 most important factors affecting the perioperative weight gain were the volume of fluid infused postoperatively in the intensive care unit ( 4,098 plus minus 916 mL in the HS group and 4,589 plus minus 1,344 mL in the NS group ) and the total diuresis after surgery ( 3,351 plus minus 1,035 mL in the HS group and 2,942 plus minus 846 mL in the NS group ) . CONCLUSIONS HS had an intense diuretic effect , which reduced intraoperative fluid retention . This effect was confirmed by the lesser increase in body weight measured on the first postoperative morning Hypertonic saline can be used for initial fluid administration before spinal anesthesia . It is effective in small-volume fluid resuscitation . This r and omized double-blinded study compared the effects of 7.5 % hypertonic saline ( HS ) and 0.9 % normal saline ( NS ) in doses containing 2 mmol/kg of sodium in 40 ASA physical status I – II patients undergoing arthroscopy or other lower limb surgery under spinal anesthesia . We infused 1.6 mL/kg of HS or 13 mL/kg of NS for initial fluid administration before spinal anesthesia induced with a 10-mg dose of 0.5 % hyperbaric bupivacaine . Etilefrine was administered to maintain mean arterial pressure at ≥80 % of its control value . Systolic and diastolic blood pressure , heart rate , and cardiac index did not differ between the groups , and the amount of etilefrine administered was similar in the treatment groups . In all our patients , the plasma sodium concentrations were within the normal range after surgery and serum osmolality was within the normal range after spinal anesthesia . The time and the volume of the first micturition were similar in both groups , despite the much smaller amount of infused free water in the HS group . We conclude that 7.5 % HS was as good as NS for the initial fluid administration before spinal anesthesia when the amount of sodium was kept unchanged . Implication s Initial fluid administration with isotonic fluids is often used for the prevention of hypotension before spinal anesthesia . We infused 1.6 mL/kg of hypertonic saline 7.5 % or 13 mL/kg of normal saline for the initial fluid administration and found that , by using hypertonic saline solution , effective initial fluid administration can be achieved without excess free water administration Background : Haemorrhagic shock is treated effectively by infusion of hypertonic saline/colloid solutions . Furthermore , previous studies found hypertonicity to affect immune responses in animals and in human blood cell cultures . It is unknown , however , whether hypertonic saline infusion affects immune responses in humans Objective : To evaluate the magnitude and cause of metabolic acidosis after infusion of 7.5 % sodium chloride 6 % dextran 70 . Design : R and omized , prospect i ve clinical study . Setting : University hospital . Patients : Two groups of 14 patients each , undergoing repair of abdominal aortic aneurysm . Interventions : Patients were r and omly assigned to receive either 250 mL of hypertonic saline dextran ( HSD ) or a conventional fluid regimen with 250 mL of hydroxyethyl starch in normal saline solution ( H-NS ) during the period of aortic clamping . Additionally , normal saline was used in both groups to reach a target pulmonary artery occlusion pressure of 15–18 mmHg . pH , Paco2 , and serum concentrations of sodium , potassium , magnesium , calcium , chloride , lactate , albumin , and phosphate were measured . Strong ion difference was calculated as ( sodium + potassium + magnesium + calcium ) − ( chloride + lactate ) . The amount of weak plasma acid was calculated . Measurements and Main Results : The infusion of HSD result ed in an immediate large increase in serum sodium ( 19 mmol/L ) and chloride ( 22 mmol/L ) , whereas the infusion of H-NS led only to mild increases in serum sodium ( 3 mmol/L ) and chloride ( 6 mmol/L ) . Both HSD and H-NS caused concomitant and equal decreases in the amount of weak plasma acid , strong ion difference , and pH ( 7.28–7.30 ) . The reduction of bicarbonate was also identical and proportional to the extent of dilution due to infusion of HSD and H-NS . This induced metabolic acidosis was corrected spontaneously in both groups 24 hrs after surgery . Conclusion : Both the intravenous administration of 7.5 % sodium chloride and the conventional fluid regimen with saline-based 6 % hydroxyethyl starch solution result ed in a metabolic acidosis of equal extent . This suggests dilution of plasma buffers or a decrease in strong ion difference to be the primary cause of metabolic acidosis We tested hypertonic saline solution ( HS ) to determine its effectiveness in surgical procedures for prostatic hypertrophy . We r and omly selected 40 patients undergoing elective transurethral resection of the prostate for either infusion of  HS ( 3 % NaCl ) at 4ml·kg−1·min−1 ( HS group ) or lactated Ringer 's solution ( LR ) at 8 ml·kg−1·min−1 ( LR group ) . Anesthesiologists regulated the intraoperative infusion rate as needed to maintain blood pressure . There were no differences in systolic blood pressure , heart rate , central venous pressure , or arterial blood oxygenation between the two groups . In the HS group , plasma sodium , chloride , and osmolality , measured in the recovery room , were significantly increased ; however , they returned to preanesthetic levels the day after surgery . In the LR group , in contrast , plasma sodium decreased significantly and this lower value persisted for 1 day . An osmolar gap exceeding 10mOsm·kg−1 was observed in 2 patients in the HS group , but plasma sodium remained at normal values . However , in the 1 patient in the LR group whose osmolar gap exceeded 10mOsm·kg−1 , plasma sodium was 115 mEq·I−1 . HS , at a low dose , is useful in the intraoperative management of transurethral resection of the prostate AIM To investigate the effects of 7.5 % hypertonic saline on positive fluid balance and negative fluid balance , after radical surgery for gastrointestinal carcinoma . METHODS Fifty-two patients with gastrointestinal carcinoma undergoing radical surgery were studied . The patients were assigned to receive either Ringer lactate solution following 4 mL/kg of 7.5 % hypertonic saline ( the experimental group , n = 26 ) or Ringer lactate solution ( the control group , n = 26 ) during the early postoperative period in SICU . Fluid infusion volumes , urine outputs , fluid balance , body weight change , PaO2/FiO2 ratio , anal exhaust time as well as the incidence of complication and mortality were compared between the two groups . RESULTS Urine outputs on the operative day and the first postoperative day in experimental group were significantly more than in control group ( P<0.000001 , P = 0.000114 ) . Fluid infusion volumes on the operative day and the first postoperative day were significantly less in experimental group than in control group ( P = 0.000042 , P = 0.000415 ) . The volumes of the positive fluid balance on the operative day and during the first 48 h after surgery , in experimental group , were significantly less than in control group ( P<0.000001 ) . Body weight gain post-surgery was significantly lower in experimental group than in control group ( P<0.000001 ) . The body weight fall in experimental group occurred earlier than in control group ( P<0.000001 ) . PaO2/FiO2 ratio after surgery was higher in experimental group than in control group ( P = 0.000111 ) . The postoperative anal exhaust time in experimental group was earlier than in control group ( P = 0.000006 ) . The overall incidence of complications and the incidence of pulmonary infection were lower in experimental group than in control group ( P = 0.0175 , P = 0.0374 ) . CONCLUSION 7.5 % hypertonic saline has an intense diuretic effect and causes mobilization of the retained fluid , which could reduce fluid infusion volumes and positive fluid balance after radical surgery for gastrointestinal carcinoma , as well as , accelerate the early appearance of negative fluid balance after the surgery , improve the oxygen diffusing capacity of the patients ' alveoli , and lower the overall incidence of complications and pulmonary infection after the surgery We have compared the haem 
    Output:
    
HS reduces the volume of intravenous fluid required to maintain patients undergoing surgery but transiently increases serum sodium .