Intraoperative fluid therapy by lactated Ringer's solution with various concentrations of potassium

Lactated Ringer's solutions, whose concentration of potassium was 10 or 20 mEq.l-1, were infused into 10 and 9 patients undergoing surgical operations under general anesthesia, respectively. Effects of these fluid therapies on serum potassium and blood sugar were studied comparing with the effect of infusion of regular lactated Ringer's solution. A decrease in serum potassium concentration seen with the regular lactated Ringer's solution during the surgery was minimized with the lactated Ringer's solutions of 10 or 20 mEq.l-1 of potassium. With the lactated Ringer's solutions of higher concentrations of potassium, an increase in blood sugar level, which was noted with the regular lactated Ringer's solution, was not observed although all the lactated Ringer's solutions contained 0.7% of glucose. Furthermore, base excess remained at a normal level in patients of high potassium groups, but it decreased in patients of the regular potassium group. Lactated Ringer's solutions of high potassium levels are useful to maintain serum potassium and glucose levels at more normal levels during surgical procedures under general anesthesia.     

Effects of lactated Ringer's solutions on human leukocytes

BACKGROUND: The standard lactated Ringer's (LR) solution contains racemic lactate, an equal mixture of D(-)- and L(+)-isomers. The aim of this study was to investigate whether racemic LR solution (containing both isomers, dl-LR) differs from LR containing L-isomer only (L-LR). METHODS: Blood from 20 volunteers was incubated for 30 minutes with lactated Ringer's solutions containing the DL- or L-form of lactate, Hank's balanced salt solution, normal saline, and ketone Ringer's (lactate replaced with ketone bodies). Neutrophil "oxidative burst" was measured using flow cytometry. Gene expression of 23 genes associated with leukocyte function was determined with cDNA array technique. The arraying procedure was repeated four times to obtain four sets of data. RESULTS: Compared with the L-LR and ketone Ringer's, DL-LR causes an increased production of reactive oxygen species by neutrophils and affects expression of leukocyte genes known to be involved in inflammation, cell migration, and apoptosis. CONCLUSION: Lactated Ringer's solution in commonly used formulation (racemic mixture, DL-LR) influences neutrophil function and leukocyte gene expression.     

Comparative study on the effects of acetated Ringer's solution,lactated Ringer's solution,Ringer's solution,and 5% glucose-acetated Ringer's solution on canine hemorrhagic shock

The abilities of acetated Ringer's solution (AR), lactated Ringer's solution (LR), Ringer's solution (R), and 5% glucose-acetated Ringer's solution (AR-D) to improve canine hemorrhagic shock were investigated. All solutions studied were infused at 1 ml·kg⁻¹·min⁻¹ for 90 min after base excess (BE) reached about −13 mEq·l⁻¹ by maintaining the mean blood pressure (MBP) at 40 mmHg. MBP, renal blood flow (RBF), vertebral blood flow (VBF), and urinary output significantly increased after the start of infusion of AR, LR, R, and AR-D. The VBF and urinary output were particularly improved with AR-D. The arterial blood level of HCO ₃ ⁻ and BE were also increased after the start of infusion of AR, LR, and AR-D but not of R. AR infusion improved BE more effectively than LR. Although AR-D, AR, and LR increased HCO ₃ ⁻ , the blood pH did not increase in AR-D. The value of plasma acetate increased after the start of infusion of AR and AR-D but not of LR, and R. On the other hand, plasma lactate and pyruvate levels were higher with LR than with AR. The increase in the lactate/pyruvate ratio induced by LR was larger than that by AR. The plasma norepinephrine and epinephrine levels decreased after the start of all infusions. Plasma insulin and glucose levels were markedly increased after the start of AR-D infusion but were not affected by AR, LR, and R. These results indicate that the effectiveness of various infusion solutions such as AR, LR, R, and AR-D during canine hemorrhagic shock varies. AR-D may be useful for increasing both peripheral blood flow and urine output. AR may also be useful for improvement in metabolic acidosis and surgical diabetes induced by hemorrhagic shock.     

Are lactated Ringer's solution and normal saline solution equal with regard to coagulation?

Crystalloids represent an attractive strategy to alleviate intravascular volume deficits. Crystalloid hemodilution was associated with hypercoagulability in in vitro and in vivo studies. The influence of different crystalloids on coagulation in the surgical patient is not well studied. In a prospective, randomized study in patients undergoing major abdominal surgery, we used either lactated Ringer's solution (RL) (n = 21) or 0.9% saline solution (SS) (n = 21) exclusively for intravascular volume replacement over 48 h to maintain central venous pressure between 8 and 12 mm Hg. Activated thrombelastography (TEG) using different activators (intrinsic TEG, extrinsic TEG, heparinase TEG, aprotinin TEG) was used to measure coagulation time, clot formation time, and maximum clot firmness. Measurements were performed after induction of anesthesia (T0), immediately after surgery (T1), 5 h after surgery (T2), and on the morning of the first (T3) and second (T4) postoperative days. RL 18,750 +/- 1890 mL and 17,990 +/- 1790 mL of SS were infused during the study period. Acidosis was seen only in the SS-treated group. Blood loss was not different between the groups. Fibrinogen and antithrombin III decreased similarly at T1 and T2 in both groups, most likely because of hemodilution. Differences in TEG data from normal baseline were seen only immediately after surgery and 5 h thereafter, indicating mild hypercoagulability in the intrinsic TEG (RL, from 147 +/- 130 s to 130 +/- 11 s; SS, from 146 +/- 12 s to 131 +/- 12 s). There were no differences in coagulation between RL- and SS-treated patients. We conclude that in major abdominal surgery intravascular volume replacement with crystalloids resulted in only moderate and abbreviated changes in coagulation. No differences in activated TEG and blood loss were seen between an RL- and an SS-based intravascular volume replacement regimen. IMPLICATIONS: In 42 patients undergoing major abdominal surgery, either lactated Ringer's solution or 0.9% saline solution were exclusively used for volume therapy for 48 h. Activated thrombelastography revealed some mild hypercoagulability after surgery. No differences in coagulation were seen between the two intravascular volume replacement strategies.     

In vitro effects of different medium molecular hydroxyethyl starch solutions and lactated Ringer's solution on coagulation using SONOCLOT

Hydroxyethyl starch (HES) solutions are widely used to replace intravascular volume. HES solutions differ from each other with regard to molecular weight and mode of hydroxyl substitution (degree of hydroxylation, C2:C6 hydroxyethyl ratio, concentration), factors which may have varying effects on coagulation. We studied, in vitro, three different HES preparations (molecular weight/degree of hydroxylation/concentration/C2:C6 ratio of substitution 70.000/0. 5/6%/3.2; Pharmacia & Upjohn Co., Erlangen, Germany; 130.000/0. 4/6%/11.2 and 200.000/0.5/6%/4.6; Fresenius Co., Bad Homburg, Germany) and, for comparison, lactated Ringer's solution (RL) at 33% and 66% dilution with whole blood. The influence of hemodilution was measured by using routine laboratory variables and SONOCLOT (Sonoclot II Coagulation and Platelet Function Analyzer, Sienco Co.) analysis, using a viscoelastic test, on the cellular as well as on the plasmatic hemostatic system. For statistical analysis of quantitative data, we used nonparametric analysis of variance and adequate post hoc tests. Qualitative data were analyzed by using the nonparametric Kruskal-Wallis test. A P value below 0.05 was considered significant. In contrast to the control group with RL, the liquid phase of coagulation (activated clotting time) was slightly affected by the 33% diluted HES solutions. HES 70.000, 130. 000, and 200.000 interfered significantly with the early stage of coagulation as expressed by the clot rate (gel/fibrin formation). Clot maturation and speed of maturation (time to peak) were strongly affected by HES 70.000 at all grades of dilution. HES 130.000 showed a faster clot formation process compared with the other HES solutions. HES 130.000 diluted 33% showed a better clot retraction as compared with the other HES solutions. In conclusion, in vitro hemodilution comparing different medium molecular weight HES solutions reveals that HES 130.000 seems preferable regarding some aspects of clot formation and retraction. RL affected clot formation only minimally, except for the early activation of clotting, which was measured by a shortened activated clotting time. IMPLICATIONS: We investigated the effect of different hydroxyethyl starch (HES) solutions (70.000, 130.000, 200.000) on coagulation. Regarding clot formation and retraction, HES 130.000 had some advantages over the other tested HES solutions. Lactated Ringer's solution affected coagulation only minimally, except for the early stage of clot formation.     

Concurrent expansion of plasma volume and left ventricular end-diastolic volume in patients after rapid infusion of 5% albumin and lactated Ringer's solution

STUDY OBJECTIVE: To examine the effects of plasma volume expansion on plasma volume, left ventricular end-diastolic volume (LVEDV), and cardiac index (CI) after rapid fluid infusion, as knowledge of the degree of concordance between plasma and cardiac preload expansion could optimize LVEDV expansion without administering excessive fluid. DESIGN: Randomized, double-blinded study. SETTING: Academic community hospital. PATIENTS: 20 patients undergoing elective coronary artery bypass surgery. INTERVENTIONS: Patients were administered either 5% albumin (5 mL/kg) or lactated Ringer's solution (25 mL/kg) over 30 minutes, just before incision. MEASUREMENTS: Serial measurements of plasma volume, LVEDV by transesophageal echocardiography, and CI were recorded. MAIN RESULTS: Albumin expanded plasma volume and LVEDV to a similar degree (11.3% and 13.2%). In contrast, lactated Ringer's solution increased plasma volume more than LVEDV (21.7% vs 14.4%; P = 0.0005). Increased LVEDV significantly but poorly correlated with increased CI (r(2) = 0.2, P < 0.0001) for both fluids. However, LVEDV expansion was brief and returned to baseline or less within 30 minutes for both fluids despite continued plasma volume expansion and increased CI. Correspondingly, rates of decline from peak expansion were significantly faster for LVEDV than plasma volume expansion for both albumin (-1.9% + 1.9%/min vs -0.1% + 0.1%/min; P = 0.0008) and lactated Ringer's (-1.1% + 0.8%/min vs -0.4% + 0.2%/min; P = 0.006). CONCLUSIONS: Intravenous fluids increased LVEDV to a lesser extent and duration than did plasma volume expansion. Monitoring of LVEDV was a poor guide for fluid administration to maximize CI.     

The effects of lactated Ringer's solution infusion on cardiac output changes after spinal anesthesia

We evaluated the effects of an infusion of lactated Ringer's (LR) solution on changes in cardiac output (CO) after spinal anesthesia. Seventy-five patients scheduled for lower extremity surgery under spinal anesthesia were studied. We measured CO (impedance cardiography method) and blood pressure for 25 min before and 30 min after spinal anesthesia. Patients were randomly assigned to three groups. In the No Infusion group, no LR solution was given during the period of measurements. The LR Before group received 12 mL/kg of LR solution within 20 min before spinal anesthesia. The LR After group received 12 mL/kg of LR solution within 20 min starting immediately after spinal anesthesia. After spinal anesthesia, CO decreased by 13.9% in the No Infusion group. In the LR Before group, CO increased after the infusion by 20% and returned to baseline value 30 min after spinal anesthesia. In the LR After group, CO increased after spinal anesthesia, and 30 min after spinal anesthesia, CO was 11.3% above baseline. We conclude that the decrease in CO after spinal anesthesia can be prevented by the infusion of an LR solution, with CO reaching the highest value while the infusion is running. IMPLICATIONS: We studied the effects of lactated Ringer's solution infusion on cardiac output changes after spinal anesthesia. If the patients received no infusion, cardiac output decreased after spinal anesthesia. However, if the patients received lactated Ringer's solution infusion, cardiac output was maintained.     

A prospective randomized study of hydroxyethyl starch, albumin, and lactated Ringer's solution as priming fluid for cardiopulmonary bypass

The ideal priming fluid for cardiopulmonary bypass is not known. We designed a study to determine whether there are important differences in the clinical effects of hydroxyethyl starch versus albumin when used in priming fluid, and in the clinical effects of colloid versus crystalloid priming fluid. We prospectively randomized 83 adult patients undergoing coronary artery bypass or valve replacement. All patients were managed by standardized protocol, and they received one of three priming fluids for bypass: hydroxyethyl starch (HES), 26 patients; albumin (ALB), 28 patients, and lactated Ringer's solution (LRS), 29 patients. The groups were stratified by body weight and type of operation. We measured 41 variables relating to operative time factors, fluid balance, bleeding, and organ function (renal, cardiac, and pulmonary) at several time intervals. The LRS group had a significantly lower colloid osmotic pressure than the other two groups, and the HES group had a substantially higher blood viscosity. Although the prothrombin time was significantly lower in the LRS group (p less than 0.05), the differences were very small and not clinically important. The platelet count in the HES group was significantly lower than in the other two groups immediately after bypass, but it was not different by the time the patients left the operating room. There were no differences among the groups in chest tube drainage, blood bank usage, or fluid balance. Postoperatively, the pulmonary shunt fraction was significantly greater in the LRS group. Body weight increased more in the LRS than in the HES and ALB groups (p = 0.01). No adverse reaction to the prime solutions was noted. The differences between the HES and ALB groups--prothrombin time, platelet count, and blood viscosity--had no apparent clinical effects; thus, the two may be considered clinically equivalent. The greater somatic and pulmonary fluid accumulation in the LRS group suggests that colloid is preferable to crystalloid in priming fluid.     

A case of anaphylactoid reactions to lactated Ringer's solution with 5% maltose

A 27-years-old man was admitted for correction of nasal fracture. He presented with circulatory collapse and generalised erythema on induction of general anesthesia and during preparation of intradermal test for identifying the offending agent. As both of these responses occurred during intravenous infusion of lactated Ringer's solution with 5% maltose, anaphylactoid responses to this intravenous solution were strongly suspected.     

Cardiovascular effects of 6% hetastarch and lactated Ringer's solution during spinal anesthesia.

BACKGROUND AND OBJECTIVES: The purpose of this prospective, randomized, double-blinded study was to compare the hemodynamic effects of 6% hetastarch with lactated Ringer's solution and to determine the main reasons for hemodynamic impairment following spinal anesthesia in elderly patients undergoing emergent hip surgery. METHODS: After receiving institutional approval and informed consent, we enrolled 24 ASA physical status III patients for this study. Hemodynamics were recorded with pulmonary artery and arterial catheters and an electrocardiogram. Following fluid administration with either 500 mL 6% hetastarch (group H) or 1500 mL lactated Ringer's solution (group R), spinal anesthesia was administered with 3.0 mL 0.5% bupivacaine (isobaric). Hemodynamic measurements were recorded prior to fluid administration, before spinal anesthesia, and 10, 20, and 30 minutes following spinal anesthesia and reported as relative changes relating to baseline. RESULTS: Although the hemodynamic measurements after spinal anesthesia remained stable in group H throughout the observation period, blood pressure, central venous pressure, pulmonary artery (PA) wedge pressure and systemic vascular resistance decreased significantly in group R (blood pressure: -7 +/- 10 vs - 14 +/- 8% 30 minutes after spinal anesthesia, P < .05 to group R; central venous pressure: 51 +/- 106 vs -26 +/- 27% 10 minutes, 63 +/- 89 vs -36 +/- 30% 20 minutes and 73 +/- 112 vs -33 +/- 29% 30 minutes after spinal anesthesia, P < .01 to group R; PA wedge pressure: 40 +/- 37 vs -5 +/- 40% 10 minutes, 40 +/- 35 vs -23 +/- 32% 20 minutes and 38 +/- 36 vs -23 +/- 32% 30 minutes after spinal anesthesia, P < .01 to group R; systemic vascular resistance: -10 +/- 16 vs -18 +/- 7% 20 minutes and -10 +/- 15 vs - 19 +/- 12% 30 minutes after spinal anesthesia, P < .05 to group R). CONCLUSIONS: Six percent hetastarch minimizes the hemodynamic responses during spinal anesthesia in elderly patients undergoing emergent hip surgery. In this study population, spinal anesthesia-induced hemodynamic impairment is caused by decreases in cardiac filling pressures and systemic vascular resistance.     

Effects of University of Wisconsin and lactated Ringer's solutions to ischemia-reperfusion injury in isolated cremaster flap

Ischemia-reperfusion (I/R) injury is a topic that has been much-discussed by various researchers during the last decade in plastic surgery. Though much progress has occurred, the problem is not totally solved yet. In particular, the pathophysiology of reperfusion injury in skeletal muscle has not been clearly elucidated. The aims of this study are to assess the effects of a variety of perfusants on the microcirculation after reperfusion injury and to better understand the pathophysiology of reperfusion injury. Isolated cremaster flaps were performed in 44 rats, preserving the femoral artery and vein in order to cannulate with microtubes. There were 2 control and 2 experiment groups. In one of the control groups and in both experimental groups, 2 h of ischemia were applied by clamping the iliac vessels. Immediately after this, the muscle was locally perfused and washed with lactated Ringer's (LR) and University of Wisconsin (UW) solutions, given from the femoral artery and drained by the femoral vein in the two respective experimental groups. The effects of these solutions to I/R injury were shown at the microcirculatory level via measuring and determining preischemic and postischemic diameters of arterioles and venules, tissue perfusion, capillary density, velocity of red blood cells, and leukocyte sticking. Both tested perfusion solutions were found to be harmful in all parameters. This study demonstrates that both LR and UW solutions aggravate I/R injury.     

The volume kinetics of acetated Ringer's solution during laparoscopic cholecystectomy

We studied the distribution and elimination of an IV infusion of 20 mL/kg of acetated Ringer's solution (approximately 1500 mL) over 60 min in 12 women undergoing laparoscopic cholecystectomy. A plasma dilution of 4.2% developed during the induction of general anesthesia, even though fluid was withheld. The additional plasma dilution induced by the subsequent volume expansion was slightly larger than expected from previous volunteer experiments and averaged 18%. The diuretic response to intravascular fluid administration was small, and only 20% of the infused fluid had been excreted 4 h later. Volume kinetic analysis showed that the IV fluid expanded a central body fluid space by 3.2 L. The clearance constants for distribution and elimination averaged 115 mL/min and 6.8 mL/min, respectively. These data represent a half-life of the fluid in the patients that is 17 times longer (median, 4.5 h) than the half-life of the plasma dilution (16 min), indicating a strong tendency to the formation of peripheral edema. A nomogram based on the kinetic variables suggests that infusion rates should be relatively rapid early on during surgery but slower later. This strategy creates a constant plasma dilution at any desired level without causing undue peripheral accumulation of fluid.