***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Ninety‐seven parturients undergoing elective Caesarean section were allocated  r and omly to have their legs elevated to approximately 30 ° on pillows or elevated and wrapped with elasticated Esmarch b and ages or neither ( controls ) following spinal anaesthesia . All patients received intravenous crystalloid ( 20 ml.kg−1 over 20 min ) prior to spinal injection and were placed in the left lateral tilt position . Significant hypotension was treated with intravenous ephedrine in 5 mg bolus doses . Leg wrapping result ed in a significant reduction in the incidence ofpostspinal hypotension in comparison to the control group ( 18 % compared to 53 % , p = 0.004 ) . This represents a five‐fold reduction in the likelihood ofpostspinal hypotension ( odds ratio 5.3 , 95 % CI 1.7–16.3 ) . Leg elevation alone did not significantly reduce the incidence of hypotension ( 39 % ) . There was no significant difference in the time of onset of hypotension between the groups . For those patients requiring ephedrine , there was no significant difference in mean dose requirements between the groups . The use of leg compression immediately postspinal provides a simple means of reducing the accompanying hypotension and should be used more widely Seventy-eight pregnant women at term , scheduled for elective cesarean section , were enrolled in this multicenter trial to compare the analgesic efficacy and side effect profile of a spinal block with hyperbaric bupivacaine alone ( Group B ) or combined with 75 [ micro sign]g of clonidine ( Group BC ) or with clonidine 75 [ micro sign]g and fentanyl 12.5 [ micro sign]g ( Group BCF ) . Intraoperatively , clonidine increased the spread of the sensory block and decreased pain ( pain scores 23 + /- 7 mm vs 17 + /- 6 and 2 + /- 1 mm for Group B versus Groups BC and BCF ; P < 0.05 ) and analgesic supplementation . This improved analgesia was best with the clonidine-fentanyl combination ( Group BC versus Group BCF ; P < 0.05 ) . Postoperative analgesia was prolonged only in Group BCF ( 215 + /- 79 min vs 137 + /- 35 and 183 + /- 80 min for Group BCF versus Groups B and BC ; P < 0.05 ) . Blood pressure and heart rate changes were not significantly different among groups , whereas sedation and pruritus were significantly more frequent in Group BCF . Nausea and vomiting were decreased in Groups BC and BCF . Apgar scores and umbilical artery blood pH were not different among groups . We conclude that adding a small dose of intrathecal clonidine to bupivacaine increases the quality of intraoperative analgesia and decreases pain during cesarean section . Combining clonidine with fentanyl further improved analgesia . Implication s : In this study , we demonstrate improved intraoperative spinal analgesia by adding 75 [ micro sign]g of clonidine to bupivacaine ; side effects were not increased . The combination of clonidine and fentanyl further improved analgesia but moderately increased sedation and pruritus . ( Anesth Analg 1998;87:609 - 13 Abstract Purpose . This study aim ed to compare low-molecular weight hydroxyethyl starch containing 1 % dextrose ( HES ) infusion and lactated Ringer 's solution ( LR ) in the prevention of hypotension associated with spinal anesthesia for cesarean section . Methods . Sixty-seven patients scheduled for cesarean section under spinal anesthesia were r and omly allocated to receive either LR ( n= 35 ) or HES ( n= 32 ) infusion before cesarean delivery . Infusion of the fluid was started immediately after arrival at the operating room , through two fully open i.v . routes of 18 or 16 gauge . The two groups were compared in terms of the incidence of hypotension ; ephedrine dose ; cord and maternal blood gas , hemoglobin , and glucose ; and Apgar scores . Results . Intravenous fluid volume until delivery in the LR group was significantly greater than that in the HES group ( 1298 ± 503 and 973 ± 339 ml , respectively ) in spite of the similar periods of intravenous infusion ( 18.1 ± 3.9 and 18.2 ± 4.1 min ) . The incidence of hypotension , and the ephedrine dose , blood gas analyses , and Apgar scores were not significantly different between the groups . The ephedrine dose correlated with the anesthesia level by spinal anesthesia ( P < 0.05 ) . Conclusion . This study did not show an advantage of HES compared with LR in the prevention of hypotension or in the reduction of ephedrine dose during cesarean section under spinal anesthesia . The anesthesia level , rather than the choice of intravenous fluid solution , might be related to the ephedrine dose We r and omized women having elective Caesarean section to receive either no preload ( control group , n=33 ) or 4 % gelatin solution ( Gelofusine ) 15 ml kg(-1 ) ( colloid group , n=35 ) i.v . before spinal anaesthesia . Intravenous metaraminol was titrated at 0.25 - 0.75 mg min(-1 ) to maintain systolic arterial pressure ( SAP ) in the target range 90 - 100 % of baseline after the spinal injection . The control group required more  vasopressor  in the first 10 min [ median 1.7 ( range 0 - 2.9 ) mg vs 1.4 ( 0 - 2.8 ) , P=0.02 ] at a greater maximum infusion rate [ 0.5 ( 0 - 0.75 ) vs 0.25 ( 0 - 0.5 ) mg min(-1 ) , P=0.0005 ] and had a lower minimum SAP [ 90 ( 51 - 109 ) vs 101 ( 75 - 127 ) mm Hg , P=0.006 ] than the colloid group . Nausea was less frequent in the colloid group ( 6 vs 24 % ) but neonatal outcome was similar in the two groups . Colloid preload improved haemodynamic stability but did not affect neonatal outcome when arterial pressure was maintained with an infusion of metaraminol during spinal anaesthesia for Caesarean section Abstract We have routinely applied an extra-strong graduated compression stocking to cesarean section patients to reduce the incidence of spinal anesthesia hypotension . Because bupivacaine has recently become available in Japan , we compared the incidence of spinal hypotension using either 2.0 ml of hyperbaric 0.3 % dibucaine or 0.5 % bupivacaine . There were 98 full-term parturients wearing the stocking who received 2.0 ml injection of dibucaine or bupivacaine for elective cesarean section . When systolic blood pressure decreased to 90–100 mm Hg or to less than 70 % of the pre-anesthesia value , ephedrine was injected intravenously . There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the dibucaine and bupivacaine groups . Although the demographic data and various data related to anesthesia or surgery were similar in the groups , the fluid volume and the dose and incidence of ephedrine injection during anesthesia showed significant differences : the mean dose was 3.6 and 1.5 mg and the incidence was 41 % and 19 % in the dibucaine and bupivacaine groups , respectively . Spinal anesthesia using bupivacaine results in a lower incidence of spinal hypotension compared with dibucaine and , in combination with fitting the extra-strong stockings onto both legs , is clinical ly useful for cesarean sections Maternal and neonatal catecholamine concentrations , following the use of either phenylephrine or ephedrine to treat a drop in maternal blood pressure after spinal anaesthesia for caesarean delivery , were compared . Patients were r and omly assigned to one of two groups : Group 1 patients ( n = 20 ) were treated with ephedrine given as 5 mg intravenous bolus injections ; Group 2 patients ( n = 20 ) were treated with phenylephrine given as 40 μg intravenous bolus injections , for decreases in maternal systolic blood pressure to maintain maternal systolic blood pressure above 100 mmHg . Maternal vein ( MV ) , umbilical vein ( UV ) , and umbilical artery ( UA ) blood sample s were taken at the time of delivery . Sample s were analyzed for catecholamine concentrations and blood gas values The value of intravenous crystalloid administration in preventing spinal-induced hypotension in the parturient has recently been question ed . Also , the association between increasing crystalloid volume and decreasing postpartum colloid osmotic pressure ( COP ) raises concern regarding the risk of maternal and fetal pulmonary edema . To study the dose-response effect of varying amounts of crystalloid volume prior to spinal anesthesia , we measured maternal hemodynamic variables and maternal and fetal COP in three groups of healthy parturients receiving spinal anesthesia for elective cesarean delivery . Fifty-five parturients were r and omized in a double-blind fashion to receive one of 10 , 20 , or 30 mL/kg of crystalloid volumes prior to induction of spinal anesthesia . Measurements included mean arterial blood pressure ( MAP ) , cardiac index ( CI ) , and systemic vascular resistance index ( SVRI ) recorded using noninvasive thoracic impedance monitoring until delivery . Maternal and neonatal COP were measured . All groups showed declines in MAP and SVRI from baseline at 5 min after spinal anesthesia , but the amount of decline did not differ among groups . Total ephedrine and additional intravenous ( IV ) fluid administered did not differ among groups . The 20- and 30- mL/kg groups showed a larger decline in maternal COP than the 10-mL/kg group ; no differences in neonatal COP were seen with varying preload . We conclude that increasing the amount of IV crystalloid administered to 30 mL/kg in the healthy parturient does not significantly alter maternal hemodynamics or ephedrine requirements after spinal anesthesia and has no apparent benefit . ( Anesth Analg 1996;83:299 - 303 Purpose To study how the body h and les fluid given intravenously during the onset of spinal anaesthesia  in women scheduled for Caesarean section . Methods The effect of spinal anaesthesia on the volume kinetics of a constant-rate infusion of 25 ml · kg−1 of Ringer ’s solution ( n = 11 ) and 10 ml · kg−1 of dextran 3 % 60 ( n = 8) was studied before elective Caesarean section , Measurements of the blood haemoglobin concentration and urine excretion served as input variables in calculations of the size(s ) of the body fluid spaces exp and ed by the infused fluid . The blood glucose level was also monitored . Results When a one-volume kinetic model were fitted to the data , spinal anaesthesia reduced the size of the exp and ed body fluid space by 30 % ( Ringer ’s ) and 58 % ( dextran ) ( P < 0.02 ) When a two-volume model was statistically justified , anaesthesia reduced the rate of fluid equilibration between the two exp and ed body fluid spaces by 47 % and 19 % , respectively ( P < 0.04 ) The baseline volume for the primary ( central ) fluid space was smaller than the expected plasma volume ; 1.5 l for Ringer ’s solution and 0.9 l for dextran . Only small changes in the blood glucose concentration were found . Conclusion The onset of spinal anaesthesia induces acute changes in the body ’s h and ling of infused fluid that can be described by volume kinetic analysis .RésuméObjectifÉtudier le devenir des liquides administrés par voie intraveineuse durant l’induction de l’anesthésie rachidienne chez des parturientes subissant une césarienne . MéthodesLes effets de la rachianesthésie sur la cinétique volumétrique d’une infusion à débit constant de 25 ml · kg−1 de solution de Ringer ( n= 11 ) ou de 10 ml · kg−1 de dextran 60 en solution à 3 % ( n = 8) ont été étudiés avant la césarienne élective . Les mesures du taux d’hémoglobine sanguin et du débit urinaire ont servi comme entrées variables dans le calcul de l’expansion volémique par le liquide infusé des différents compartiments corporels . La glycémie a aussi été mesurée . RésultatsLorsque les données étaient rapportées à un modèle cinétique à un seul compartiment , l’anesthésie rachidienne entraînait une réduction du compartiment corporel déjà distendu de 30 % pour le Ringer et de 58 % pour le dextran ( P 0.02 ) . Lorsqu’un modèle à deux compartiments apparaissait justifié d’un point de vue statistique , l’anesthésie entraînait une réduction du taux d’équilibration entre les deux compartiments corporels déjà distend 
    Output:
    
REVIEW ER 'S CONCLUSIONS No studied intervention has been shown to eliminate the need to treat maternal hypotension during spinal anaesthesia for caesarean section .
We are unable to draw any conclusions regarding adverse effects of the studied interventions , due to their probable low incidence and the small number of women studied .