A Slow-Exchange Interstitial Fluid Compartment in Volunteers and Anesthetized Patients: Kinetic Analysis and Physiology.

BACKGROUND: Physiological studies suggest that the interstitial space contains 2 fluid compartments, but no analysis has been performed to quantify their sizes and turnover rates. METHODS: Retrospective data were retrieved from 270 experiments where Ringer's solution of between 238 and 2750 mL (mean, 1487 mL) had been administered by intravenous infusion to awake and anesthetized humans (mean age 39 years, 47% females). Urinary excretion and hemoglobin-derived plasma dilution served as input variables in a volume kinetic analysis using mixed-models software. RESULTS: The kinetic analysis successfully separated 2 interstitial fluid compartments. One equilibrated rapidly with the plasma and the other equilibrated slowly. General anesthesia doubled the rate constants for fluid entering these 2 compartments (from 0.072 to 0.155 and from 0.026 to 0.080 min -1 , respectively). The return flows to the plasma were impeded by intensive fluid therapy; the rate constant for the fast-exchange compartment decreased from 0.251 to 0.050 when the infusion time increased from 15 to 60 minutes, and the rate constant for the slow-exchange compartment decreased from 0.019 to 0.005 when the infused volume increased from 500 to 1500 mL. The slow-exchange compartment became disproportionately expanded when larger fluid volumes were infused and even attained an unphysiologically large size when general anesthesia was added, suggesting that the flow of fluid was restrained and not solely determined by hydrostatic and oncotic forces. The dependence of the slow-exchange compartment on general anesthesia, crystalloid infusion rate, and infusion volume all suggest a causal physiological process. CONCLUSIONS: Kinetic analysis supported that Ringer's solution distributes in 2 interstitial compartments with different turnover times. The slow compartment became dominant when large amounts of fluid were infused and during general anesthesia. These findings may explain why fluid accumulates in peripheral tissues during surgery and why infused fluid can remain in the body for several days after general anesthesia.

Albumin Infusion and Blood Loss After Cardiac Surgery.

BACKGROUND: In the recent ALBICS (ALBumin In Cardiac Surgery) trial, 4% albumin used for cardiopulmonary bypass priming and volume replacement increased perioperative bleeding compared with Ringer acetate. In the present exploratory study, albumin-related bleeding was further characterized. METHODS: Ringer acetate and 4% albumin were compared in a randomized, double-blinded fashion in 1386 on-pump adult cardiac surgery patients. The study end points for bleeding were the Universal Definition of Perioperative Bleeding (UDPB) class and its components. RESULTS: The UDPB bleeding grades were higher in the albumin group than the Ringer group: "insignificant" (albumin vs Ringer: 47.5% vs 62.9%), "mild" (12.7% vs 8.9%), "moderate" (28.7% vs 24.4%), "severe" (10.2% vs 3.2%), and "massive" (0.9% vs. 0.6%; P < .001). Patients in the albumin group received red blood cells (45.2% vs 31.5%; odds ratio [OR], 1.80; 95% CI, 1.44-2.24; P < .001), platelets (33.3% vs 21.8%; OR, 1.79; 95% CI, 1.41-2.28; P < .001), and fibrinogen (5.6% vs 2.6%; OR, 2.24; 95% CI, 1.27-3.95; P < .05), and underwent resternotomy (5.3% vs 1.9%; OR, 2.95; 95% CI, 1.55-5.60, P < .001) more often than patients in the Ringer group. The strongest predictors of bleeding were albumin group allocation (OR, 2.18; 95% CI, 1.74-2.74) and complex (OR, 2.61; 95% CI, 2.02-3.37) and urgent surgery (OR, 1.63; 95% CI, 1.26-2.13). In interaction analysis, the effect of albumin on the risk of bleeding was stronger in patients on preoperative acetylsalicylic acid. CONCLUSIONS: Perioperative administration of albumin, compared with Ringer's acetate, resulted in increased blood loss and higher UDBP class. The magnitude of this effect was similar to the complexity and urgency of the surgery.

Hydration with Lactated Ringer's solution combined with rectal diclofenac in the prevention of pancreatitis after endoscopic retrograde cholangiopancreatography. / Hidratación con Ringer Lactato combinado con diclofenaco rectal en la prevención de pancreatitis poscolangiopancreatografía retrógrada endoscópica.

OBJECTIVE: Different measures are recommended to reduce pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). We conducted a study in patients with ERCP treated with rectal diclofenac or lactated Ringer's solution, or both interventions, to assess whether there is a decrease in the number of cases of post-ERCP pancreatitis. MATERIAL AND METHODS: A mixed cohort study involving 1,896 patients from 2009 to 2018. Up to June 2012 without treatment (Group I). Subsequently, 100mg of rectal diclofenac (Group II). Since 2016, lactated Ringer's solution 200ml/hour during the procedure and 4hours after it, in addition to 500ml over 30minutes when the pancreas was cannulated (Group III). Since 2017, lactated Ringer's solution plus Diclofenac (Group IV). There were 725 patients in group I, and 530, 227 and 414 patients in groups II, III and IV, respectively. Factors predisposing to post-ERCP pancreatitis and post-ERCP pancreatitis cases that were defined by consensus criteria have been collected. RESULTS: There were 65 cases of post-ERCP pancreatitis (3.4%); 2.9%, 3.4%, 3.1% and 4.3% in groups I, II, III and IV, respectively (P=.640). In group I, there was 4.2% of post-ERCP pancreatitis in naïve papillae and 4%, 4.9% and 6.3% in groups II, III and IV, respectively (P=.585). The severity of post-ERCP pancreatitis and adverse effects were similar in all groups. 38.4% were high-risk patients. There were also no differences in post-ERCP pancreatitis in this group (P=.501). CONCLUSION: In this work, no benefit was obtained with diclofenac plus hydration in reducing the number and severity of cases of post-ERCP pancreatitis nor with the other prophylactic measures.

The Effects of Acute and Chronic Inflammation on the Dynamics of Fluid Shift of Ringer's Solution and Hemodynamics during Surgery.

The aim of this study was to investigate the influences of acute and chronic inflammation on the dynamics of fluid shift of Ringer's solution and hemodynamics in patients during surgery. Thirty-seven patients with the American Society of Anesthesiologists (ASA) grades I-II were enrolled and allocated to two study groups according to the type of disease and operation and inflammation, including patients undergoing emergency appendectomy (Acute group, n = 19) and patients undergoing elective cholecystectomy (Chronic group, n = 18). All of the patients were administered 15 mL/kg of Ringer's lactated (LR) solution at a constant rate over 35 min before the induction of anesthesia. Plasma dilution (PD), volume expansion (VE), volume expansion efficiency (VEE), and extravascular volume (EVV) were calculated based on the concentration of hemoglobin within 2 h post-infusion. Heart rate (HR), arterial blood pressure and urine output were also recorded. PD and VE peaked at the end of infusion, while VEE peaked at the beginning of infusion in all of the patients. After infusion, PD, VE and VEE in the Acute group were all higher than those in the Chronic group (p < 0.05). PD and VE were higher during anesthesia or surgery than during awake or non-surgery (p < 0.001). The mean arterial pressure (MAP) and diastolic pressure (DBP) in the Acute group were significantly lower (p < 0.001) and HR was significantly higher (p < 0.001) than in the Chronic group during the study periods. It was suggested that patients with acute inflammation be treated with individualized fluid therapy during surgery.

Protective Effects of Cold Ringer's Solution Perfusion in Abdominal Aortic Surgery Requiring Renal Artery Clamp.

BACKGROUND/AIM: Treating abdominal aortic aneurysms (AAA) of the juxtarenal artery with renal artery clamps burdens the kidneys. We investigated the outcomes of intra-operative renal artery perfusion using the cold Ringer's solution method for renal protection. PATIENTS AND METHODS: We enrolled 290 AAA patients who underwent open aortic repair. Surgical outcomes were investigated based on renal protection. RESULTS: We evaluated 231 patients requiring infrarenal artery clamp (Group I), and 59 patients requiring perfusion in addition to the clamp (Group J). Patient demographics, acute kidney injury (AKI) incidence (Group I: 11.7% and Group J: 20.3%), hospital mortality (Group I: 1.3% and Group J: 1.7%), and 30-day mortality (Group I: 0.4% and Group J: 0%) were not different between the groups. The AKI incidence was low (13%) in cases requiring a renal artery clamp for ≥45 min (n=40). CONCLUSION: Perfusion with cold Ringer's solution offers renal protection and may improve surgical outcomes.

The effects of intravenous dextrose 5%, Ringer's solution, and oral intake on the duration of labor stages in nulliparous women: a double-blind, randomized, controlled trial.

Background and objectives: Childbirth consists of a three-stage period beginning with uterine contractions and ending in the expulsion of the placenta. The present study was conducted to compare the effects of Ringer's solution, dextrose solution 5%, and oral intake on the duration of total labor and labor stages (primary outcome) and the frequency of oxytocin administration and prolonged labor (secondary outcome) in nulliparous women with spontaneous vaginal delivery.Materials and methods: The present randomized clinical trial was conducted on 201 nulliparous women in labor assigned with a randomized block design to three groups, each receiving either Ringer's solution plus oral fluids, dextrose solution 5% solution plus oral fluids or oral fluids alone. The solutions were intravenously administered at a rate of 125 ml/h in the groups receiving the solutions and the subjects in the oral fluids group could consume liquids of their choice (water, orange juice, and apple juice). The duration of total labor and labor stages (the active stage, the second, and third stages of labor) were recorded by the researcher in minutes. Furthermore, the frequency of oxytocin administration and prolonged labor were recorded by the researcher by using a checklist. Data were analyzed using the Kruskal-Wallis test, Mann-Whitney's U-test, chi- square test and Fisher exact test.Results: The mean (±SD) duration of total labor was 301.2 (±50.0) minutes in the Ringer group, 171.9 (±36.4) in the dextrose 5% group, and 524.8 (±103.4) in the oral fluids group, suggesting a statistically significant intergroup difference (p < .001). The mean (±SD) duration of the active stage of labor was 276.7 (±91.3) minutes in the Ringer group, 150.6 (±78.5) in the dextrose 5% group, and 302.4 (±136.8) in the oral fluids group, suggesting a statistically significant intergroup difference (p < .001). A significant difference was also observed between the three groups in terms of the duration of the third stage of labor (p < .001); however, no significant differences were observed in terms of the duration of the second stage of labor (p = .058). Furthermore, a significant difference was observed between the three groups in terms of the need for oxytocin administration (p ≤ .001) and the frequency of prolonged labor (p = .001).Conclusion: The results suggest that the consumption of dextrose solution by nulliparous women reduces the duration of labor, the need for oxytocin administration and the frequency of prolonged labor compared to when Ringer's solution and oral fluids are used.

Assessment of Fluid Responsiveness in Prone Neurosurgical Patients Undergoing Protective Ventilation: Role of Dynamic Indices, Tidal Volume Challenge, and End-Expiratory Occlusion Test.

BACKGROUND: In patients in the prone position, the reliability of pulse pressure variation and stroke volume variation (PPV and SVV) and the use of functional hemodynamic tests to predict fluid responsiveness have not previously been established. Perioperatively, in this setting, optimizing fluid management can be challenging, and fluid overload is associated with both intraoperative and postoperative complications. We designed this study to assess the sensitivity and specificity of baseline PPV and SVV, the tidal volume (VT) challenge (VTC) and the end-expiratory occlusion test (EEOT) in predicting fluid responsiveness during elective spinal surgery. METHODS: The study protocol was started during a period of intraoperative hemodynamic stability after prone positioning and before the administration of any vasopressor: (1) at baseline, the controlled ventilation was set at 6 mL/kg of predicted body weight (PBW) (T0); (2) patients underwent the first EEOT (EEOT6) by interrupting the mechanical ventilation for 30 seconds; (3) the ventilation was set again at 6 mL/kg PBW for 1 minute (T1); (4) the VTC was applied by increasing the VT up to 8 mL/kg PBW for 1 minute; (5) the ventilation was kept at 8 mL/kg PBW for 1 minute (T2); (6) a second EEOT (EEOT8) was performed; (7) the VT was reduced back to 6 mL/kg PBW for 1 minute (T3); (8) a fluid challenge of 250 mL of Ringer's solution was infused over 10 minutes. After each step, a complete set of hemodynamic measurements was recorded. RESULTS: Neither PPV and SVV values recorded at T3 nor the EEOT6 or the EEOT8 predicted fluid responsiveness. The change in PPV after VTC application predicted fluid responsiveness with an area under the curve of 0.96 (95% confidence interval, 0.87-1.00), showing a sensitivity of 95.2% and a specificity of 94.7%, using a cutoff increase of 12.2%. The change in SVV after VTC application predicted fluid responsiveness with an area under the curve 0.96 (95% confidence interval, 0.89-1.00) showing a sensitivity of 95.2% and a specificity of 94.7%, using a cutoff increase of 8.0%. A linear correlation between stroke volume index changes after fluid challenge administration and the changes in PPV and SVV after VTC application was observed (r = 0.71; P < .0001 and r = 0.68; P < .0001, respectively). CONCLUSIONS: In prone elective neurosurgical patients, the baseline values of PPV and SVV and the EEOT fail to predict fluid responsiveness, while the VTC is a very reliable functional hemodynamic test and could be helpful in guiding intraoperative fluid therapy.

Effect of acute volume overload on echocardiographic indices of right ventricular function and dyssynchrony assessed by use of speckle tracking echocardiography in healthy dogs.

OBJECTIVE To determine the relationship between acute volume overload and echocardiographic indices of right ventricular (RV) function and dyssynchrony in healthy dogs. ANIMALS 7 healthy Beagles. PROCEDURES Right heart catheterization and echocardiography were performed in 7 healthy anesthetized Beagles at baseline and after induction of volume overload. Volume overload was induced by IV infusion of lactated Ringer solution (150 mL/kg/h for 90 minutes). Echocardiographic indices of RV function, including peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, RV Tei index, RV longitudinal strain (RVLS), and systolic RV longitudinal strain rate (RVLSR), were obtained by use of speckle tracking echocardiography (STE). In addition, SD of the systolic shortening time of the right ventricle for the 6 segments (RV-SD6) was determined with STE. RESULTS Volume overload significantly increased the RV end-diastolic pressure, compared with the baseline value. Echocardiographic indices of RV function, except for septal RVLSR, were significantly enhanced by volume overload. In contrast, RV-SD6 did not change with volume overload. Although echocardiographic indices of RV function, except for septal RVLSR, were correlated with RV end-diastolic pressure, RV-SD6 was not correlated. CONCLUSIONS AND CLINICAL RELEVANCE Echocardiographic indices of RV function, including RVLS and RVLSR, were affected by acute short-term volume overload. Therefore, results for assessment of RV function by use of STE in dogs with clinical conditions associated with right-sided chronic volume overload, such as tricuspid and pulmonic regurgitation, should be interpreted with caution.

A Clinical Trial of the Effect of Warm Intravenous Fluids on Core Temperature and Shivering in Patients Undergoing Abdominal Surgery.

PURPOSE: This study was conducted to investigate the effect of warm intravenous fluids on shivering and core temperature of patients undergoing abdominal surgery. DESIGN: This study was a two-group clinical-control trial. METHODS: Ringer's solution at normal room temperature and serum at 38°C were infused in the control and intervention groups, respectively. Shivering, core temperature, SpO2, and vital signs were measured at admission to the operating room and postanesthesia care unit (PACU) and 30 minutes after the admission to the PACU. FINDINGS: There was a significant difference between the two groups in terms of shivering, core temperature, and pulse rate at the time of admission to the PACU and 30 minutes after. CONCLUSIONS: Ringer's solution at 38°C instead of room temperature can be used to reduce the incidence of postanesthetic hypothermia and shivering in patients undergoing abdominal surgery. Using this method in addition to other nursing care is recommended preoperatively.

Prophylactic Effects of Ephedrine, Ondansetron and Ringer on Hemodynamic Changes during Cesarean Section under Spinal Anesthesia - a randomized clinical trial.

BACKGROUND: Hemodynamic change during spinal anaesthesia for cesarean section is prevalent. OBJECTIVE: Comparing the prophylactic effects of ephedrine, ondansetron and ringer on hemodynamic changes in patients undergoing cesarean section with spinal anaesthesia. MATERIAL AND METHODS: This randomized clinical trial was carried out on pregnant women undergoing elective cesarean sec-tion referred to teaching hospitals of Mashhad, Iran. Patients allocated to three groups of intravenous ondansetron (O) (4 mg, 5 min),intramuscular ephedrine (E) (25 mg, 25 min) and ringer (R) (500 ml, 20 min) prior to spinal anaesthesia. Anaesthesia inducted with 10-15 mg of bupivacaine. Vital signs were recorded every 3 minutes for 18 minutes including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate (PR), pulse oximetry (SpO2). RESULTS: Ninety patients with a mean age of 29.4 ± 5.4 years were studied in three groups of O (n = 30), E (n = 30), R (n = 30). Results showed a statistically significant difference in the incidence rate of hypotension 12 minutes after spinal anaesthesia in the three groups, but no statistically significant difference was found in the rest of minutes among the three groups. Dur-ing follow-up minutes, bradycardia was observed in only one patient (1.1%) of Group O and no cases of this sign were observed in other minutes and other groups. CONCLUSION: Intramuscular administration of ephedrine 25 minutes prior to the spinal anaesthesia leads to better prevention of systolic blood pressure changes compared with intravenous ondansetron and ringer, while administration of ondansetron and ringer had the same effects on reducing hemodynamic changes.

Effects of three infusion fluids with different sodium chloride contents on steady-state serum concentrations of bromide in dogs.

Potassium bromide overdose (bromism) in the management of canine epilepsy has been known. However, a protocol to reduce bromide concentrations rapidly has not been previously established. The effects of three infusion fluids with different chloride contents on the steady-state serum concentrations of bromide in beagles were determined. After stabilization of the serum bromide concentrations, seven dogs were infused with saline (Na+ 154 mmol/L; Cl- 154 mmol/L), lactated Ringer's (Na+ 131 mmol/L; Cl- 110 mmol/L), or maintenance solutions (Na+ 35 mmol/L; Cl- 35 mmol/L) at a rate of 2 or 10 ml kg-1  hr-1 for 5 hr. Serum and urine were collected hourly, and the bromide concentrations were measured. When saline and lactated Ringer's solutions were infused at a rate of 10 ml kg-1  hr-1 for 5 hr, serum bromide concentrations were decreased by 14.24% and urine bromide concentrations by 17.63%, respectively. Of all compositions of infusion fluids, only sodium and chloride contents were associated with the decreased serum concentrations and the increased renal clearance of bromide. In summary, saline and lactated Ringer's solutions reduced serum bromide concentrations in a sodium chloride-dependent manner in dogs were found when infused at 10 ml kg-1  hr-1 for 5 hr.

The effect of various doses of infusion solutions on the endothelial glycocalyx layer in laparoscopic cholecystectomy patients.

BACKGROUND: The endothelial glycocalyx is located on the luminal side of blood vessels and maintains vessel integrity. This study analysed how various dosages of infusion affected the secretion of atrial natriuretic peptide (ANP) and potential glycocalyx damage in patients undergoing laparoscopic cholecystectomy. We hypothesised that the liberal administration of Ringer's solution during the operation can cause iatrogenic hypervolemia with releasing of ANP and glycocalyx damage. METHODS: The study included 90 patients with American Society of Anesthesiologists' (ASA) class I and II, in good cardiopulmonary health, who were assigned to one of three groups: Restrictive group, which received 1 mL/kg/hr intraoperatively and six hours postoperatively; Low liberal group, which received 5 mL/kg/hr of Ringer's solution intraoperatively and six hours postoperatively and High liberal group, which received 15 mL/kg/hr intraoperatively and 10 mL/kg/hr six hours postoperatively. We measured patients' concentrations of glycocalyx constituents, ANP, markers of kidney and liver function, C-reactive protein (CRP), and albumine at three time points. We also measured noinvasive hemodynamics, the correlation between ANP secretion and the concentration of glycocalyx components. RESULTS: We found a significantly higher concentrations of hyaluronic acid and syndecan-1 and more ANP secretion in the High liberal group than in the other groups. We also observed a positive correlation between ANP secretion and glycocalyx constituent concentration. Markers of kidney and liver function were normal, suggesting preservation of splanchnic perfusion and global hemodynamics. CONCLUSIONS: Measuring the endothelial glycocalyx constituents in circulating blood could be a marker of intraoperative volume overload during laparoscopic operations.

Are we close to the ideal intravenous fluid?

The approach to i.v. fluid therapy for hypovolaemia may significantly influence outcomes for patients who experience a systemic inflammatory response after sepsis, trauma, or major surgery. Currently, there is no single i.v. fluid agent that meets all the criteria for the ideal treatment for hypovolaemia. The physician must choose the best available agent(s) for each patient, and then decide when and how much to administer. Findings from large randomized trials suggest that some colloid-based fluids, particularly starch-based colloids, may be harmful in some situations, but it is unclear whether they should be withdrawn from use completely. Meanwhile, crystalloid fluids, such as saline 0.9% and Ringer's lactate, are more frequently used, but debate continues over which preparation is preferable. Perhaps most importantly, it remains unclear how to select the optimal dose of fluid in different patients and different clinical scenarios. There is good reason to believe that both inadequate and excessive i.v. fluid administration may lead to poor outcomes, including increased risk of infection and organ dysfunction, for hypovolaemic patients. In this review, we summarize the current knowledge on this topic and identify some key pitfalls and some areas of agreed best practice.