Choices in fluid type and volume during resuscitation: impact on patient outcomes

Tangential flow filtration facilitated fractionation of polymerized human serum albumin: Insights into the effects of molecular size on biophysical properties

Human serum albumin (HSA) is currently used as a plasma expander (PE) to increase blood volume during hypovolemic conditions, such as blood loss. However, its effectiveness is suboptimal in septic shock and burn patients due to their enhanced endothelial permeability, resulting in HSA extravasation into the tissue space leading to edema, and deposition of toxic HSA-bound metabolites. Hence, to expand HSA's applicability toward treating patients with compromised endothelial permeability, HSA has been previously polymerized to increase its molecular size thus compartmentalizing the polymerized HSA (PolyHSA) molecules in the vascular space. Previous studies bracketed PolyHSA between 100 kDa and 0.2 μm. In this research, PolyHSA was synthesized at two cross-link densities 43:1 and 60:1 (i.e., molar ratios of glutaraldehyde to HSA) and subsequently fractionated via tangential flow filtration (TFF) into two narrower brackets: bracket A (500 kDa and 0.2 μm) and bracket B (50-500 kDa). PolyHSA within the same size bracket at different cross-link densities exhibited similar solution viscosity, zeta potential, and osmolality but differed in hydrodynamic diameter. At the same cross-link density, the PolyHSA A bracket showed higher viscosity, lowered zeta potential, and a larger hydrodynamic diameter compared with the PolyHSA B bracket while maintaining osmolality. Interestingly, PolyHSA 43:1 B, PolyHSA 60:1 A, and PolyHSA 60:1 B brackets exhibited colloid osmotic pressure similar to HSA, indicating their potential to serve as PEs.

A Systematic Review and Meta-Analysis of Prehospital Plasma Administration for Hemorrhagic Shock

Introduction

Hemorrhagic shock demands swift intervention. Management involves the rapid infusion of blood products to restore circulation and uphold tissue perfusion. The aim of this study was to evaluate the effectiveness of prehospital plasma administration in trauma patients, comparing outcomes with normal saline. This was a meta-analysis of randomized controlled trials.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline, searches were conducted in PubMed, MEDLINE, and the Cochrane Central Register of Controlled Trials from August 1, 2018, to April 4, 2023. The PubMed search string included terms related to blood plasma, prehospital care, emergency medical services, and hemorrhagic shock: (Blood Plasma [MeSH Terms] OR fresh frozen plasma [MeSH Terms] OR plasma OR fresh frozen plasma OR FFP) AND (Prehospital OR emergency care, prehospital [MeSH Terms] OR prehospital emergency care [MeSH Terms] OR prehospital OR prehospital OR EMS OR emergency medical service [MeSH Terms]) AND (hemorrhagic shock [MeSH Terms] OR hemorrhage OR hemorrhage OR hemorrhagic shock OR hemorrhagic shock). Results from the trials were pooled using a random effects model, presented as risk ratios with 95% confidence intervals.

Results

In the analysis of 760 patients from three studies, outcomes included mortality at 24 h and 28 days, multi-organ failure (MOF), acute lung injury, and vasopressor use within 24 h. Patients were divided into plasma (363) and normal saline (397) groups.

Conclusion

There is no distinction between prehospital plasma administration and normal saline concerning mortality at 24 and 28 days or the need for vasopressors within 24 h. Moreover, plasma administration did not appear to influence rates of acute lung injury or MOF.

Fluid resuscitation in children with severe infection and septic shock: a systematic review and meta-analysis

This study aimed to evaluate the current evidence on various aspects of fluid therapy such as type, volume, and timing of fluid bolus administration in children with septic shock. Systematic review and meta-analysis of clinical trials including children less than 18 years of age admitted to the pediatric emergency and intensive care unit with severe infection and shock requiring fluid resuscitation. The intervention included balanced crystalloids (BC) vs normal saline (NS), colloids vs NS, restricted vs liberal fluid bolus, and slow vs fast fluid bolus. The primary outcome was mortality rate. Of the 219 citations retrieved, 12 trials (3526 children with severe infection with or without malaria and shock) were included. The pooled results found no significant difference in the mortality rate between groups comparing balanced crystalloids (BC) vs normal saline (NS), colloids vs NS, restricted vs liberal fluid bolus, and slow vs fast fluid bolus. The risk of acute kidney injury (AKI) was significantly less in the BC group compared to the NS group. The certainty of evidence for mortality was of "moderate certainty" in the BC vs NS group, and was of "very low certainty" for the other two groups.

CONCLUSIONS

The current meta-analysis found no significant difference in the mortality rate between the types of resuscitation fluid, and their speed or volume of administration. However, a significantly decreased risk of AKI was found in the BC group. More evidence is needed regarding the speed and volume of administration of fluid boluses in critically ill children.Prospero registration: CRD42020209066.

WHAT IS KNOWN

• Balanced crystalloids (BC) may be better than normal saline (NS) for fluid resuscitation in critically ill children.

WHAT IS NEW

• BC are better than NS for fluid resuscitation in critically ill children as they decrease AKI and hyperchloremia.

Comparison of noninvasive cardiac output and stroke volume measurements using electrical impedance tomography with invasive methods in a swine model

Pulmonary artery catheterization (PAC) has been used as a clinical standard for cardiac output (CO) measurements on humans. On animals, however, an ultrasonic flow sensor (UFS) placed around the ascending aorta or pulmonary artery can measure CO and stroke volume (SV) more accurately. The objective of this paper is to compare CO and SV measurements using a noninvasive electrical impedance tomography (EIT) device and three invasive devices using UFS, PAC-CCO (continuous CO) and arterial pressure-based CO (APCO). Thirty-two pigs were anesthetized and mechanically ventilated. A UFS was placed around the pulmonary artery through thoracotomy in 11 of them, while the EIT, PAC-CCO and APCO devices were used on all of them. Afterload and contractility were changed pharmacologically, while preload was changed through bleeding and injection of fluid or blood. Twenty-three pigs completed the experiment. Among 23, the UFS was used on 7 pigs around the pulmonary artery. The percentage error (PE) between COUFS and COEIT was 26.1%, and the 10-min concordance was 92.5%. Between SVUFS and SVEIT, the PE was 24.8%, and the 10-min concordance was 94.2%. On analyzing the data from all 23 pigs, the PE between time-delay-adjusted COPAC-CCO and COEIT was 34.6%, and the 10-min concordance was 81.1%. Our results suggest that the performance of the EIT device in measuring dynamic changes of CO and SV on mechanically-ventilated pigs under different cardiac preload, afterload and contractility conditions is at least comparable to that of the PAC-CCO device. Clinical studies are needed to evaluate the utility of the EIT device as a noninvasive hemodynamic monitoring tool.

Multiple Electrolytes Solution Versus Saline as Bolus Fluid for Resuscitation in Pediatric Septic Shock: A Multicenter Randomized Clinical Trial

OBJECTIVE

To determine if initial fluid resuscitation with balanced crystalloid (e.g., multiple electrolytes solution [MES]) or 0.9% saline adversely affects kidney function in children with septic shock.

DESIGN

Parallel-group, blinded multicenter trial.

SETTING

PICUs of four tertiary care centers in India from 2017 to 2020.

PATIENTS

Children up to 15 years of age with septic shock.

METHODS

Children were randomized to receive fluid boluses of either MES (PlasmaLyte A) or 0.9% saline at the time of identification of shock. All children were managed as per standard protocols and monitored until discharge/death. The primary outcome was new and/or progressive acute kidney injury (AKI), at any time within the first 7 days of fluid resuscitation. Key secondary outcomes included hyperchloremia, any adverse event (AE), at 24, 48, and 72 hours, and all-cause ICU mortality.

INTERVENTIONS

MES solution ( n = 351) versus 0.9% saline ( n = 357) for bolus fluid resuscitation during the first 7 days.

MEASUREMENTS AND MAIN RESULTS

The median age was 5 years (interquartile range, 1.3-9); 302 (43%) were girls. The relative risk (RR) for meeting the criteria for new and/or progressive AKI was 0.62 (95% CI, 0.49-0.80; p < 0.001), favoring the MES (21%) versus the saline (33%) group. The proportions of children with hyperchloremia were lower in the MES versus the saline group at 24, 48, and 72 hours. There was no difference in the ICU mortality (33% in the MES vs 34% in the saline group). There was no difference with regard to infusion-related AEs such as fever, thrombophlebitis, or fluid overload between the groups.

CONCLUSIONS

Among children presenting with septic shock, fluid resuscitation with MES (balanced crystalloid) as compared with 0.9% saline resulted in a significantly lower incidence of new and/or progressive AKI during the first 7 days of hospitalization.

The effect of restrictive fluid management on outcomes among geriatric hip fractures: a retrospective cohort study at five level I trauma centers

Restrictive fluid management (RFM) for hemodynamically unstable trauma patients has reduced mortality rates. The objective was to determine whether RFM benefits geriatric hip fracture patients, who are usually hemodynamically stable.

Design

Retrospective propensity-matched study.

Setting

Five Level I trauma centers (January 1, 2018-December 12, 2018).

Patients

Geriatric patients (65 years or older) with hip fractures were included in this study. Patients with multiple injuries, nonoperative management, and preoperative blood products were excluded.

Intervention

Patients were grouped by fluid volume (normal saline, lactated Ringer, dextrose, electrolytes, and medications) received preoperatively or ≤24 hours of arrival; patients with standard fluid management (SFM) received ≥150 mL and RFM <150 mL of fluids.

Main Outcome Measurements

The primary outcomes were length of stay (LOS), delayed ambulation (>2 days postoperatively), and mortality. Paired Student t-tests, Wilcoxon paired rank sum tests, and McNemar tests were used; an α value of < 0.05 was considered statistically significant.

Results

There were 523 patients (40% RFM, 60% SFM); after matching, there were 95 patients per arm. The matched patients were well-balanced, including no difference in time from arrival to surgery. RFM and SFM patients received a median of 80 mL and 1250 mL of preoperative fluids, respectively (P < 0.001). Postoperative fluid volumes were 1550 versus 2000 mL, respectively, (P = 0.73), and LOSs were similar between the two groups (5 versus 5 days, P = 0.83). Mortality and complications, including acute kidney injuries, were similar. Delayed ambulation rates were similar overall. When stratified by preinjury ambulation status, SFM was associated with delayed ambulation for patients not walking independently before injury (P = 0.01), but RFM was not (P = 0.09).

Conclusions

RFM seems to be safe in terms of laboratory results, complications, and disposition. SFM may lead to delayed ambulation for patients who are not walking independently before injury.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Unraveling the Contribution of Fluid Therapy to the Development of Augmented Renal Clearance in a Piglet Model

Augmented renal clearance (ARC) observed in the critically ill pediatric population has received an increased attention over the last years due to its major impact on the disposition and pharmacokinetics of mainly renally excreted drugs. Apart from an important inflammatory trigger, fluid administration has been suggested to contribute to the development of ARC. Therefore, the primary objective of this study was to evaluate the effect of continuous intravenous fluid administration on renal function using a conventional piglet animal model and to quantify the impact of fluid administration on the pharmacokinetics of renally excreted drugs. At baseline, twenty-four piglets (12 treatment/12 control; 7 weeks old, all ♂) received the marker drugs iohexol (64.7 mg/kg body weight (BW)) and para-aminohippuric acid (10 mg/kg BW) to quantify glomerular filtration rate and effective renal plasma flow, respectively. In addition, the hydrophilic antibiotic amikacin (7.5 mg/kg BW) was administered. Following this baseline measurement, the treatment group received fluid therapy as a constant rate infusion of 0.9% saline at 6 mL/kg/h over 36 h. After 24 h of fluid administration, the marker drugs and amikacin were administered again. When comparing both groups, a significant effect of fluid administration on the total body clearances of iohexol (p = 0.032) and amikacin (p = 0.0014) was observed. Clearances of iohexol and amikacin increased with on average 15 and 14%, although large interindividual variability was observed. This led to decreased systemic exposure to amikacin, which was manifested as decrease in area under the plasma concentration-time curve from time 0 h to infinity from 34,807 to 30,804 ng.h/mL. These results suggest that fluid therapy is a key factor involved in the development of ARC and should be taken into account when administering mainly renally excreted drugs. However, further research is necessary to confirm these results in children.

Resuscitation fluid practices in Brazilian intensive care units: a secondary analysis of Fluid-TRIPS

Objective

To describe fluid resuscitation practices in Brazilian intensive care units and to compare them with those of other countries participating in the Fluid-TRIPS.

Methods

This was a prospective, international, cross-sectional, observational study in a convenience sample of intensive care units in 27 countries (including Brazil) using the Fluid-TRIPS database compiled in 2014. We described the patterns of fluid resuscitation use in Brazil compared with those in other countries and identified the factors associated with fluid choice.

Results

On the study day, 3,214 patients in Brazil and 3,493 patients in other countries were included, of whom 16.1% and 26.8% (p < 0.001) received fluids, respectively. The main indication for fluid resuscitation was impaired perfusion and/or low cardiac output (Brazil: 71.7% versus other countries: 56.4%, p < 0.001). In Brazil, the percentage of patients receiving crystalloid solutions was higher (97.7% versus 76.8%, p < 0.001), and 0.9% sodium chloride was the most commonly used crystalloid (62.5% versus 27.1%, p < 0.001). The multivariable analysis suggested that the albumin levels were associated with the use of both crystalloids and colloids, whereas the type of fluid prescriber was associated with crystalloid use only.

Conclusion

Our results suggest that crystalloids are more frequently used than colloids for fluid resuscitation in Brazil, and this discrepancy in frequencies is higher than that in other countries. Sodium chloride (0.9%) was the crystalloid most commonly prescribed. Serum albumin levels and the type of fluid prescriber were the factors associated with the choice of crystalloids or colloids for fluid resuscitation.

Intravenous Fluid Management in Critically Ill Adults: A Review

TOPIC

This article reviews the management of intravenous fluids and the evaluation of volume status in critically ill adults.

CLINICAL RELEVANCE

Intravenous fluid administration is one of the most common interventions in the intensive care unit. Critically ill patients have dynamic fluid requirements, making the management of fluid therapy challenging. New literature suggests that balanced salt solutions may be preferred in some patient populations.

PURPOSE OF PAPER

The bedside critical care nurse must understand the properties of various intravenous fluids and their corresponding impact on human physiology. The nurse's clinical and laboratory assessments of each patient help define the goals of fluid therapy, which will in turn be used to determine the optimal patient-specific selection and dose of fluid for administration. Nurses serve a vital role in monitoring the safety and efficacy of intravenous fluid therapy. Although this intervention can be lifesaving, inappropriate use of fluids has the potential to yield detrimental effects.

CONTENT COVERED

This article discusses fluid physiology and the goals of intravenous fluid therapy, compares the types of intravenous fluids (isotonic crystalloids, including 0.9% sodium chloride and balanced salt solutions; hypotonic and hypertonic crystalloids; and colloids) and their adverse effects and impact on hemodynamics, and describes the critical care nurse's essential role in selecting and monitoring intravenous fluid therapy.

Comparison of the trometamol-balanced solution with two other crystalloid solutions for fluid resuscitation of a rat hemorrhagic model

Currently, the optimal resuscitation fluid remains debatable. Therefore, in the present study, we designed a trometamol-balanced solution (TBS) for use as a resuscitation fluid for hemorrhagic shock. Hemorrhagic shock was induced in 18 male Wistar-Kyoto rats, which were assigned to normal saline (NS), Ringer's solution (RS), and TBS groups. During the hemorrhagic state, their hemodynamic parameters were recorded using an Abbott i-STAT analyzer with the CG4+ cartridge (for pH, pressure of carbon dioxide, pressure of oxygen, total carbon dioxide, bicarbonate, base excess, oxygen saturation, and lactate), the CG6+ cartridge (for sodium, potassium, chloride, blood glucose, blood urea nitrogen, hematocrit, and hemoglobin), and enzyme-linked immunosorbent assay kits (calcium, magnesium, creatinine, aspartate aminotransferase, alanine aminotransferase, bilirubin, and albumin). Similar trends were found for the parameters of biochemistries, electrolytes, and blood gas, and they revealed no significant changes after blood withdrawal-induced hemorrhagic shock. However, the TBS group showed more effective ability to correct metabolic acidosis than the NS and RS groups. TBS was a feasible and safe resuscitation solution in this study and may be an alternative to NS and RS for resuscitation in hemorrhagic shock patients without liver damage.

Superior Survival Outcomes of a Polyethylene Glycol-20k Based Resuscitation Solution in a Preclinical Porcine Model of Lethal Hemorrhagic Shock

OBJECTIVE

To compare early outcomes and 24-hour survival after LVR with the novel polyethylene glycol-20k-based crystalloid (PEG-20k), WB, or hextend in a preclinical model of lethal HS.

BACKGROUND

Posttraumatic HS is a major cause of preventable death. Current resuscitation strategies focus on restoring oxygen-carrying capacity (OCC) and coagulation with blood products. Our lab shows that PEG-20k is an effective non-sanguineous, LVR solution in acute models of HS through mechanisms targeting cell swelling-induced microcirculatory failure.

METHODS

Male pigs underwent splenectomy followed by controlled hemorrhage until lactate reached 7.5-8.5 mmol/L. They were randomized to receive LVR with PEG-20k, WB, or Hextend. Surviving animals were recovered 4 hours post-LVR. Outcomes included 24-hour survival rates, mean arterial pressure, lactate, hemoglobin, and estimated intravascular volume changes.

RESULTS

Twenty-four-hour survival rates were 100%, 16.7%, and 0% in the PEG-20k, WB, and Hextend groups, respectively (P = 0.001). PEG-20k significantly restored mean arterial press, intravascular volume, and capillary perfusion to baseline, compared to other groups. This caused complete lactate clearance despite decreased OCC. Neurological function was normal after next-day recovery in PEG-20k resuscitated pigs.

CONCLUSION

Superior early and 24-hour outcomes were observed with PEG-20k LVR compared to WB and Hextend in a preclinical porcine model of lethal HS, despite decreased OCC from substantial volume-expansion. These findings demonstrate the importance of enhancing microcirculatory perfusion in early resuscitation strategies.

The Need for a Physiological Classification of Hemorrhagic Shock

Classifications mean to conceptualize in a cluster and rapidly summarize the assessment and management of a clinical scenario. In the specific case of a hemorrhagic shock (HS), a classification should serve the purpose of allowing a rapid clinical assessment of the shock level and the earliest or right timing of source control, possibly also on whether to apply damage control surgery (DCS) strategy or not. ATLS® classification of HS is not sensitive and specific enough to help decision-making in reference to the timing of management, based only on the amount of blood loss that may be or may not rightly estimated, for example, blood loss on the floor in penetrating injuries before theatre. Moreover, it focuses also on other parameters, which are taken singularly, instead of the individual generalized physiological response to hemorrhage, which is the core by definition of the derangement we call "shock." It is unhelpful, difficult, and impractical to apply as well. A new classification, which may well be called as the "physiological HS classification" or "therapeutic HS classification," was proposed since 2010, following the new developments on microcirculation and an already going-on sensible praxis among some trauma surgeons. It bases on some physiological considerations such as the significance of fluid-blood resistant hypotension, body natural hemostatic mechanisms, the right definition of shock, and the relevance that hemorrhage-triggered ischemia-reperfusion toxemia and systemic inflammatory response have in critical illness scenarios as secondary insults from ischemia, which is what we mean to prevented with DCS. The key factor remains the persistence of hypotension, following fluid challenge.

The Effect of Fluid Loading and Hypertonic Saline Solution on Cortical Cerebral Microcirculation and Glycocalyx Integrity

BACKGROUND

Fluid loading and hyperosmolar solutions can modify the cortical brain microcirculation and the endothelial glycocalyx (EG). This study compared the short-term effects of liberal fluid loading with a restrictive fluid intake followed by osmotherapy with hypertonic saline (HTS) on cerebral cortical microcirculation and EG integrity in a rabbit craniotomy model.

METHODS

The experimental rabbits were allocated randomly to receive either <2 mL/kg/h (group R, n=14) or 30 mL/kg/h (group L, n=14) of balanced isotonic fluids for 1 hour. Then, the animals were randomized to receive 5 mL/kg intravenous infusion of either 3.2% saline (group HTS, n=14) or 0.9% saline (group normal saline, n=13) in a 20-minute infusion. Microcirculation in the cerebral cortex based on sidestream dark-field imaging, a morphologic index of glycocalyx damage to sublingual and cortical brain microcirculation (the perfused boundary region), and serum syndecan-1 levels were evaluated.

RESULTS

Lower cortical brain perfused small vessel density (P=0.0178), perfused vessel density (P=0.0286), and total vessel density (P=0.0447) were observed in group L, compared with group R. No differences were observed between the HTS and normal saline groups after osmotherapy. Cerebral perfused boundary region values (P=0.0692) and hematocrit-corrected serum syndecan-1 levels (P=0.0324) tended to be higher in group L than in group R animals.

CONCLUSIONS

Liberal fluid loading was associated with altered cortical cerebral microcirculation and EG integrity parameters. The 3.2% saline treatment did not affect cortical cerebral microcirculation or EG integrity markers.

Population Kinetics of 0.9% Saline Distribution in Hemorrhaged Awake and Isoflurane-anesthetized Volunteers

BACKGROUND

Population-based, pharmacokinetic modeling can be used to describe variability in fluid distribution and dilution between individuals and across populations. The authors hypothesized that dilution produced by crystalloid infusion after hemorrhage would be larger in anesthetized than in awake subjects and that population kinetic modeling would identify differences in covariates.

METHODS

Twelve healthy volunteers, seven females and five males, mean age 28 ± 4.3 yr, underwent a randomized crossover study. Each subject participated in two separate sessions, separated by four weeks, in which they were assigned to an awake or an anesthetized arm. After a baseline period, hemorrhage (7 ml/kg during 20 min) was induced, immediately followed by a 25 ml/kg infusion during 20 min of 0.9% saline. Hemoglobin concentrations, sampled every 5 min for 60 min then every 10 min for an additional 120 min, were used for population kinetic modeling. Covariates, including body weight, sex, and study arm (awake or anesthetized), were tested in the model building. The change in dilution was studied by analyzing area under the curve and maximum plasma dilution.

RESULTS

Anesthetized subjects had larger plasma dilution than awake subjects. The analysis showed that females increased area under the curve and maximum plasma dilution by 17% (with 95% CI, 1.08 to 1.38 and 1.07 to 1.39) compared with men, and study arm (anesthetized increased area under the curve by 99% [0.88 to 2.45] and maximum plasma dilution by 35% [0.71 to 1.63]) impacted the plasma dilution whereas a 10-kg increase of body weight resulted in a small change (less than1% [0.93 to 1.20]) in area under the curve and maximum plasma dilution. Mean arterial pressure was lower in subjects while anesthetized (P < 0.001).

CONCLUSIONS

In awake and anesthetized subjects subjected to controlled hemorrhage, plasma dilution increased with anesthesia, female sex, and lower body weight. Neither study arm nor body weight impact on area under the curve or maximum plasma dilution were statistically significant and therefore no effect can be established.

0.9% saline versus Plasma-Lyte as initial fluid in children with diabetic ketoacidosis (SPinK trial): a double-blind randomized controlled trial

BACKGROUND

Acute kidney injury (AKI) is an important complication encountered during the course of diabetic ketoacidosis (DKA). Plasma-Lyte with lower chloride concentration than saline has been shown to be associated with reduced incidence of AKI in adults with septic shock. No study has compared this in DKA.

METHODS

This double-blind, parallel-arm, investigator-initiated, randomized controlled trial compared 0.9% saline with Plasma-Lyte-A as initial fluid in pediatric DKA. The study was done in a tertiary care, teaching, and referral hospital in India in children (> 1 month-12 years) with DKA as defined by ISPAD. Children with cerebral edema or known chronic kidney/liver disease or who had received pre-referral fluids and/or insulin were excluded. Sixty-six children were randomized to receive either Plasma-Lyte (n = 34) or 0.9% saline (n = 32).

MAIN OUTCOMES

Primary outcome was incidence of new or progressive AKI, defined as a composite outcome of change in creatinine (defined by KDIGO), estimated creatinine clearance (defined by p-RIFLE), and NGAL levels. The secondary outcomes were resolution of AKI, time to resolution of DKA (pH > 7.3, bicarbonate> 15 mEq/L & normal sensorium), change in chloride, pH and bicarbonate levels, proportion of in-hospital all-cause mortality, need for renal replacement therapy (RRT), and length of ICU and hospital stay.

RESULTS

Baseline characteristics were similar in both groups. The incidence of new or progressive AKI was similar in both [Plasma-Lyte 13 (38.2%) versus 0.9% saline 15 (46.9%); adjusted OR 1.22; 95% CI 0.43-3.43, p = 0.70]. The median (IQR) time to resolution of DKA in Plasma-Lyte-A and 0.9% saline were 14.5 (12 to 20) and 16 (8 to 20) h respectively. Time to resolution of AKI was similar in both [Plasma-Lyte 22.1 versus 0.9% saline 18.8 h (adjusted HR 1.72; 95% CI 0.83-3.57; p = 0.14)]. Length of hospital stay was also similar in both [Plasma-Lyte 9 (8 to 12) versus 0.9% saline 10 (8.25 to 11) days; p = 0.39].

CONCLUSIONS

The incidence of new or progressive AKI and resolution of AKI were similar in both groups. Plasma-Lyte-A was similar to 0.9% Saline in time to resolution of DKA, need for RRT, mortality, and lengths of PICU and hospital stay.

TRIAL REGISTRATION

Clinical trial registry of India, CTRI/2018/05/014042 (ctri.nic.in) (Retrospectively registered).

Prophylactic plasma transfusion for patients without inherited bleeding disorders or anticoagulant use undergoing non-cardiac surgery or invasive procedures

BACKGROUND

In the absence of bleeding, plasma is commonly transfused to people prophylactically to prevent bleeding. In this context, it is transfused before operative or invasive procedures (such as liver biopsy or chest drainage tube insertion) in those considered at increased risk of bleeding, typically defined by abnormalities of laboratory tests of coagulation. As plasma contains procoagulant factors, plasma transfusion may reduce perioperative bleeding risk. This outcome has clinical importance given that perioperative bleeding and blood transfusion have been associated with increased morbidity and mortality. Plasma is expensive, and some countries have experienced issues with blood product shortages, donor pool reliability, and incomplete screening for transmissible infections. Thus, although the benefit of prophylactic plasma transfusion has not been well established, plasma transfusion does carry potentially life-threatening risks.

OBJECTIVES

To determine the clinical effectiveness and safety of prophylactic plasma transfusion for people with coagulation test abnormalities (in the absence of inherited bleeding disorders or use of anticoagulant medication) requiring non-cardiac surgery or invasive procedures.

SEARCH METHODS

We searched for randomised controlled trials (RCTs), without language or publication status restrictions in: Cochrane Central Register of Controlled Trials (CENTRAL; 2017 Issue 7); Ovid MEDLINE (from 1946); Ovid Embase (from 1974); Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCOHost) (from 1937); PubMed (e-publications and in-process citations ahead of print only); Transfusion Evidence Library (from 1950); Latin American Caribbean Health Sciences Literature (LILACS) (from 1982); Web of Science: Conference Proceedings Citation Index-Science (CPCI-S) (Thomson Reuters, from 1990); ClinicalTrials.gov; and World Health Organization (WHO) International Clinical Trials Registry Search Platform (ICTRP) to 28 January 2019.

SELECTION CRITERIA

We included RCTs comparing: prophylactic plasma transfusion to placebo, intravenous fluid, or no intervention; prophylactic plasma transfusion to alternative pro-haemostatic agents; or different haemostatic thresholds for prophylactic plasma transfusion. We included participants of any age, and we excluded trials incorporating individuals with previous active bleeding, with inherited bleeding disorders, or taking anticoagulant medication before enrolment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included five trials in this review, all were conducted in high-income countries. Three additional trials are ongoing. One trial compared fresh frozen plasma (FFP) transfusion with no transfusion given. One trial compared FFP or platelet transfusion or both with neither FFP nor platelet transfusion given. One trial compared FFP transfusion with administration of alternative pro-haemostatic agents (factors II, IX, and X followed by VII). One trial compared the use of different transfusion triggers using the international normalised ratio measurement. One trial compared the use of a thromboelastographic-guided transfusion trigger using standard laboratory measurements of coagulation. Four trials enrolled only adults, whereas the fifth trial did not specify participant age. Four trials included only minor procedures that could be performed by the bedside. Only one trial included some participants undergoing major surgical operations. Two trials included only participants in intensive care. Two trials included only participants with liver disease. Three trials did not recruit sufficient participants to meet their pre-calculated sample size. Overall, the quality of evidence was low to very low across different outcomes according to GRADE methodology, due to risk of bias, indirectness, and imprecision. One trial was stopped after recruiting two participants, therefore this review's findings are based on the remaining four trials (234 participants). When plasma transfusion was compared with no transfusion given, we are very uncertain whether there was a difference in 30-day mortality (1 trial comparing FFP or platelet transfusion or both with neither FFP nor platelet transfusion, 72 participants; risk ratio (RR) 0.38, 95% confidence interval (CI) 0.13 to 1.10; very low-quality evidence). We are very uncertain whether there was a difference in major bleeding within 24 hours (1 trial comparing FFP transfusion vs no transfusion, 76 participants; RR 0.33, 95% CI 0.01 to 7.93; very low-quality evidence; 1 trial comparing FFP or platelet transfusion or both with neither FFP nor platelet transfusion, 72 participants; RR 1.59, 95% CI 0.28 to 8.93; very low-quality evidence). We are very uncertain whether there was a difference in the number of blood product transfusions per person (1 trial, 76 participants; study authors reported no difference; very low-quality evidence) or in the number of people requiring transfusion (1 trial comparing FFP or platelet transfusion or both with neither FFP nor platelet transfusion, 72 participants; study authors reported no blood transfusion given; very low-quality evidence) or in the risk of transfusion-related adverse events (acute lung injury) (1 trial, 76 participants; study authors reported no difference; very low-quality evidence). When plasma transfusion was compared with other pro-haemostatic agents, we are very uncertain whether there was a difference in major bleeding (1 trial; 21 participants; no events; very low-quality evidence) or in transfusion-related adverse events (febrile or allergic reactions) (1 trial, 21 participants; RR 9.82, 95% CI 0.59 to 162.24; very low-quality evidence). When different triggers for FFP transfusion were compared, the number of people requiring transfusion may have been reduced (for overall blood products) when a thromboelastographic-guided transfusion trigger was compared with standard laboratory tests (1 trial, 60 participants; RR 0.18, 95% CI 0.08 to 0.39; low-quality evidence). We are very uncertain whether there was a difference in major bleeding (1 trial, 60 participants; RR 0.33, 95% CI 0.01 to 7.87; very low-quality evidence) or in transfusion-related adverse events (allergic reactions) (1 trial; 60 participants; RR 0.33, 95% CI 0.01 to 7.87; very low-quality evidence). Only one trial reported 30-day mortality. No trials reported procedure-related harmful events (excluding bleeding) or quality of life.

AUTHORS' CONCLUSIONS

Review findings show uncertainty for the utility and safety of prophylactic FFP use. This is due to predominantly very low-quality evidence that is available for its use over a range of clinically important outcomes, together with lack of confidence in the wider applicability of study findings, given the paucity or absence of study data in settings such as major body cavity surgery, extensive soft tissue surgery, orthopaedic surgery, or neurosurgery. Therefore, from the limited RCT evidence, we can neither support nor oppose the use of prophylactic FFP in clinical practice.

A Double-Blind, Randomized Control Trial of Rapidly Infused High Strong Ion Difference (SID) Fluid Versus Hartmann's Solution on Acid-Base Status in Sepsis Patients in the Emergency Department

BACKGROUND

Balanced fluids are preferred in initial resuscitation of septic patients based on several recent studies. The Stewart's concept on acid-base balance predicts that high strong ion difference (SID) fluid thus will increase the pH level. To date, the impact of high SID fluid in septic patient with metabolic acidosis remains uncertain. We conducted single center, randomized, double-blind trial to compare the effect of high SID fluid vs. Hartmann's solution on acid-base status in selected sepsis patients in the Emergency Department.

METHODS

Septic patient with hyperlactatemia and metabolic acidosis were randomized to receive either high SID fl uid or Hartmann's solution during initial fl uid resuscitation. The primary outcome measures the pH and bicarbonate levels difference pre- and post- resuscitation.

RESULTS

One hundred and sixty-two patients underwent randomization, 81 were assigned each to receive high SID fluid or Hartmann's solution. Both groups had similar baseline characteristics. High SID group received 23.5 mL/kg and the Hartmann's group received 22.7 mL/kg (p = 0.360). High SID fluid increased the mean (± SD) pH by 0.107 (± 0.09) vs. Hartmann's solution by 0.014 (± 0.12), p ≤ 0.001. Mean bicarbonate level increased signifi cantly in high SID group compared to Hartmann's (4.30 ± 3.76 vs. 1.25 ± 3.33, p ≤ 0.001). High SID group had higher post resuscitation lactate clearance than Hartmann's group (25.4 ± 28.3% vs. 12.0 ± 34.1%, p = 0.009). Shorter hospital stay was observed in highSID group 8.04 ± 5.96 days vs. Hartmann's group 12.18 ± 12.41 days (p = 0.048). Both groups showed no difference in incidence of pulmonary oedema, acute kidney injury and mortality.

CONCLUSIONS

Initial resuscitation using high SID fluid in selected septic patient improves pH and bicarbonate levels. The high SID group had better post resuscitation lactate clearance and shorter hospital stay.

The role of endothelial glycocalyx in health and disease

The endothelium is the largest organ in the body and recent studies have shown that the endothelial glycocalyx (eGCX) plays a major role in health and disease states. The integrity of eGCX is vital for homoeostasis and disruption of its structure and function plays a major role in several pathologic conditions. An increased understanding of the numerous pathophysiological roles of eGCX may lead to the development of potential surrogate markers for endothelial injury or novel therapeutic targets. This review provides a state-of-the-art update on the structure and function of the eGCX, emphasizing the current understanding of interorgan crosstalk between the eGCX and other organs that might also contribute to the pathogenesis of kidney diseases.

Optimal crystalloid volume ratio for blood replacement for maintaining hemodynamic stability and lung function: an experimental randomized controlled study

BACKGROUND

Crystalloids are first line in fluid resuscitation therapy, however there is a lack of evidence-based recommendations on the volume to be administered. Therefore, we aimed at comparing the systemic hemodynamic and respiratory effects of volume replacement therapy with a 1:1 ratio to the historical 1:3 ratio.

METHODS

Anesthetized, ventilated rats randomly included in 3 groups: blood withdrawal and replacement with crystalloid in 1:1 ratio (Group 1, n = 11), traditional 1:3 ratio (Group 3, n = 12) and a control group with no interventions (Group C, n = 9). Arterial blood of 5% of the total blood volume was withdrawn 7 times, and replaced stepwise with different volume rations of Ringer's acetate, according to group assignments. Airway resistance (Raw), respiratory tissue damping (G) and tissue elastance (H), mean arterial pressure (MAP) and heart rate (HR) were assessed following each step of fluid replacement with a crystalloid (CR1-CR6). Lung edema index was measured from histological samples.

RESULTS

Raw decreased in Groups 1 and 3 following CR3 (p < 0.02) without differences between the groups. H elevated in all groups (p < 0.02), with significantly higher changes in Group 3 compared to Groups C and 1 (both p = 0.03). No differences in MAP or HR were present between Groups 1 and 3. Lung edema was noted in Group 3 (p < 0.05).

CONCLUSIONS

Fluid resuscitation therapy by administering a 1:1 blood replacement ratio revealed adequate compensation capacity and physiological homeostasis similar with no lung stiffening and pulmonary edema. Therefore, considering this ratio promotes the restrictive fluid administration in the presence of continuous and occult bleeding.

Renal Dysfunction after Living-Donor Liver Transplantation: Experience with 500 Cases

Introduction. The possible risk factors for chronic kidney disease in transplant recipients have not been thoroughly investigated after living-donor liver transplantation. Material and Methods. A retrospective cohort study of consecutive adults who underwent living-donor liver transplantation between May 2004 and October 2016, in a single center, was conducted. Kidney function was investigated successively for all the patients throughout the study period, with 12 months being the shortest follow-up. Postoperative renal dysfunction was defined in accordance with the Chronic Kidney Disease Epidemiology Collaboration criteria. The patients' demographic data, preoperative and intraoperative parameters, and outcomes were recorded. A calcineurin inhibitor-based immunosuppressive regimen, either tacrolimus or cyclosporine, was used in all the patients. Results. Of the 413 patients included in the study, 33 (8%) who survived for ≥1 year experienced chronic kidney disease 1 year after living-donor liver transplantation. Twenty-seven variables were studied to compare between the patients with normal kidney functions and those who developed chronic kidney disease 1 year after living-donor liver transplantation. Univariate regression analysis for predicting the likelihood of chronic kidney disease at 1 year revealed that the following 4 variables were significant: operative time, P < 0.0005; intraoperative blood loss, P < 0.0005; preoperative renal impairment, P = 0.001; and graft-to-recipient weight ratio (as a negative predictor), P < 0.0005. In the multivariate regression analysis, only 2 variables remained as independent predictors of chronic kidney disease at 1 year, namely, operative time with a cutoff value of ≥714 minutes and graft-to-recipient weight ratio as a negative predictor with a cutoff value of <0.91. Conclusion. In this study, prolonged operative time and small graft-to-recipient weight ratio were independent predictors of chronic kidney disease at 1 year after living-donor liver transplantation.

Prediction of fluid responsiveness in ventilated patients

Fluid administration is the first-line therapy in patients with acute circulatory failure. The main goal of fluid administration is to increase the cardiac output and ultimately the oxygen delivery. Nevertheless, the decision to administer fluids or not should be carefully considered, since half of critically ill patients are fluid unresponsive, and the deleterious effects of fluid overload clearly documented. Thus, except at the initial phase of hypovolemic or septic shock, where hypovolemia is constant and most of the patients responsive to the initial fluid resuscitation, it is of importance to test fluid responsiveness before administering fluids in critically ill patients. The static markers of cardiac preload cannot reliably predict fluid responsiveness, although they have been used for decades. To address this issue, some dynamic tests have been developed over the past years. All these tests consist in measuring the changes in cardiac output in response to the transient changes in cardiac preload that they induced. Most of these tests are based on the heart-lung interactions. The pulse pressure or stroke volume respiratory variations were first described, following by the respiratory variations of the vena cava diameter or of the internal jugular vein diameter. Nevertheless, all these tests are reliable only under strict conditions limiting their use in many clinical situations. Other tests such as passive leg raising or end-expiratory occlusion act as an internal volume challenge. To reliably predict fluid responsiveness, physicians must choose among these different dynamic tests, depending on their respective limitations and on the cardiac output monitoring technique which is used. In this review, we will summarize the most recent findings regarding the prediction of fluid responsiveness in ventilated patients.

Next-generation, personalised, model-based critical care medicine: a state-of-the art review of in silico virtual patient models, methods, and cohorts, and how to validation them

Critical care, like many healthcare areas, is under a dual assault from significantly increasing demographic and economic pressures. Intensive care unit (ICU) patients are highly variable in response to treatment, and increasingly aging populations mean ICUs are under increasing demand and their cohorts are increasingly ill. Equally, patient expectations are growing, while the economic ability to deliver care to all is declining. Better, more productive care is thus the big challenge. One means to that end is personalised care designed to manage the significant inter- and intra-patient variability that makes the ICU patient difficult. Thus, moving from current "one size fits all" protocolised care to adaptive, model-based "one method fits all" personalised care could deliver the required step change in the quality, and simultaneously the productivity and cost, of care. Computer models of human physiology are a unique tool to personalise care, as they can couple clinical data with mathematical methods to create subject-specific models and virtual patients to design new, personalised and more optimal protocols, as well as to guide care in real-time. They rely on identifying time varying patient-specific parameters in the model that capture inter- and intra-patient variability, the difference between patients and the evolution of patient condition. Properly validated, virtual patients represent the real patients, and can be used in silico to test different protocols or interventions, or in real-time to guide care. Hence, the underlying models and methods create the foundation for next generation care, as well as a tool for safely and rapidly developing personalised treatment protocols over large virtual cohorts using virtual trials. This review examines the models and methods used to create virtual patients. Specifically, it presents the models types and structures used and the data required. It then covers how to validate the resulting virtual patients and trials, and how these virtual trials can help design and optimise clinical trial. Links between these models and higher order, more complex physiome models are also discussed. In each section, it explores the progress reported up to date, especially on core ICU therapies in glycemic, circulatory and mechanical ventilation management, where high cost and frequency of occurrence provide a significant opportunity for model-based methods to have measurable clinical and economic impact. The outcomes are readily generalised to other areas of medical care.

Preoperative fluid management in traumatic shock: A retrospective study for identifying optimal therapy of fluid resuscitation for aged patients

Fluid resuscitation was used on aged patients with traumatic shock in their early postoperative recovery. The present study aimed to assess whether different fluid resuscitation strategies had an influence on aged patients with traumatic shock.A total of 219 patients with traumatic shock were recruited retrospectively. Lactated Ringer and hydroxyethyl starch solution were transfused for fluid resuscitation before definite hemorrhagic surgery. Subjects were divided into 3 groups: group A: 72 patients were given aggressive fluid infusion at 20 to 30 mL/min to restore normal mean arterial pressure (MAP) of 65 to 75 mm Hg. Group B: 72 patients were slowly given restrictive hypotensive fluid infusion at 4 to 5 mL/min to maintain MAP of 50 to 65 mm Hg. Group C: 75 patients were given personalized infusion to achieve MAP of 75 to 85 mm Hg. Preoperative infusion volume, preoperative MAP, optimal initial points for surgery, postoperative shock time and mortality rates at 6 and 24 hours after surgery were determined.No significant difference in clinical characteristics was found among the 3 groups. Amount of preoperative infusion was considerably lower in the restrictive group (P < .01, compared with group A). A significant difference in preoperative infusion volume was found between the personalized and other 2 groups (P < .01, compared with groups A and B). Patients in the personalized resuscitation group achieved a higher preoperative MAP (P < .01 compared with Group B; P < .05, compared with group A) and required less prepared time for surgery (P < .01 compared with groups A and B). In addition, a lower mortality rate at 6 and 24 hours after operation was observed in the subjects with personalized therapy (P < .05, compared with group B).Personalized management of fluid resuscitation in traumatized aged patients with appropriate volume and speed of fluid transfusion, suggesting increased survival rate and less prepared time for surgery.

Volume-replacement ratio for crystalloids and colloids during bleeding and resuscitation: an animal experiment

Background

Fluid resuscitation remains a cornerstone in the management of acute bleeding. According to Starling's “Three-compartment model”, four-times more crystalloids have the same volume effect as colloids. However, this volume-replacement ratio remains a controversial issue as it may be affected by the degradation of the endothelial glycocalyx layer, a situation often found in the critically ill. Our aim was to compare colloid and crystalloid based fluid resuscitation during an experimental stroke volume index (SVI) guided hemorrhage and resuscitation animal model.

Methods

Anesthetized and mechanically ventilated pigs were randomized to receive a colloid (Voluven®,HES, n=15) or crystalloid (Ringerfundin®,RF, n=15) infusion. Animals were bled till baseline SVI (Tbsl) dropped by 50% (T0), followed by resuscitation until initial SVI was reached (T4) in four steps. Invasive hemodynamic measurements, blood gas analyses and laboratory tests were performed at each assessment points. Glycocalyx degradation markers (Syndecan-1/hematocrit ratio, Glypican/hematocrit ratio) were determined at Tbsl, T0 and T4.

Results

Similar amounts of blood were shed in both groups (HES group: 506±159 mls blood, RF group: 470±127 mls blood). Hemodynamic changes followed the same pattern without significant difference between the groups. Animals received significantly less resuscitation fluid in the HES compared to the RF-group: 425 [320-665], vs 1390 [884-1585] mls, p <0.001. The volume replacement ratio was 0.92 [0.79-1.54] for HES; and 3.03 [2.00-4.23] for the RF-group (p <0.001). There was no significant difference between the groups in the glycocalyx degradation markers.

Conclusion

In this moderate bleeding-resuscitation animal model the volume-replacement ratio for crystalloids and colloids followed similar patterns as predicted by Starling's principle, and the glycocalyx remained intact. This indicates that in acute bleeding events, such as trauma or during surgery, colloids may be beneficial as hemodynamic stability may be achieved more rapidly than with crystalloids.

Damage Control for Vascular Trauma from the Prehospital to the Operating Room Setting

Early management of vascular injury, starting at the field, is imperative for survival no less than any operative maneuver. Contemporary prehospital management of vascular trauma, including appropriate fluid and volume infusion, tourniquets, and hemostatic agents, has reversed the historically known limb hemorrhage as a leading cause of death. In this context, damage control (DC) surgery has evolved to DC resuscitation (DCR) as an overarching concept that draws together preoperative and operative interventions aiming at rapidly reducing bleeding from vascular disruption, optimizing oxygenation, and clinical outcomes. This review addresses contemporary DCR techniques from the prehospital to the surgical setting, focusing on civilian vascular injuries.

Management of the Critically Ill Adult With Congenital Heart Disease

Survival of adults with congenital heart disease (CHD) has improved significantly over the last 2 decades, leading to an increase in hospital and intensive care unit (ICU) admissions of these patients. Whereas most of the ICU admissions in the past were related to perioperative management, the incidence of medical emergencies from long-term sequelae of palliative or corrective surgical treatment of these patients is rising. Intensivists now are confronted with patients who not only have complex anatomy after congenital cardiac surgery, but also complex pathophysiology due to decades of living with abnormal cardiac anatomy and diseases of advanced age. Comorbidities affect all organ systems, including cognitive function, pulmonary and cardiovascular systems, liver, and kidneys. Critical care management requires an in-depth understanding of underlying anatomy and pathophysiology in order to apply contemporary concepts of adult ICU care to this population and optimize patient outcomes. In this review, the main CHD lesions and their common surgical management approaches are described, and the sequelae of CHD physiology are discussed. In addition, the effects of chronic comorbidities on the management of critically ill adults are explored, and the adjustments of current ICU management modalities and pharmacology to optimize care are discussed.

Closed-Loop- and Decision-Assist-Guided Fluid Therapy of Human Hemorrhage

OBJECTIVES

We sought to evaluate the efficacy, efficiency, and physiologic consequences of automated, endpoint-directed resuscitation systems and compare them to formula-based bolus resuscitation.

DESIGN

Experimental human hemorrhage and resuscitation.

SETTING

Clinical research laboratory.

SUBJECTS

Healthy volunteers.

INTERVENTIONS

Subjects (n = 7) were subjected to hemorrhage and underwent a randomized fluid resuscitation scheme on separate visits 1) formula-based bolus resuscitation; 2) semiautonomous (decision assist) fluid administration; and 3) fully autonomous (closed loop) resuscitation. Hemodynamic variables, volume shifts, fluid balance, and cardiac function were monitored during hemorrhage and resuscitation. Treatment modalities were compared based on resuscitation efficacy and efficiency.

MEASUREMENTS AND MAIN RESULTS

All approaches achieved target blood pressure by 60 minutes. Following hemorrhage, the total amount of infused fluid (bolus resuscitation: 30 mL/kg, decision assist: 5.6 ± 3 mL/kg, closed loop: 4.2 ± 2 mL/kg; p < 0.001), plasma volume, extravascular volume (bolus resuscitation: 17 ± 4 mL/kg, decision assist: 3 ± 1 mL/kg, closed loop: -0.3 ± 0.3 mL/kg; p < 0.001), body weight, and urinary output remained stable under decision assist and closed loop and were significantly increased under bolus resuscitation. Mean arterial pressure initially decreased further under bolus resuscitation (-10 mm Hg; p < 0.001) and was lower under bolus resuscitation than closed loop at 20 minutes (bolus resuscitation: 57 ± 2 mm Hg, closed loop: 69 ± 4 mm Hg; p = 0.036). Colloid osmotic pressure (bolus resuscitation: 19.3 ± 2 mm Hg, decision assist, closed loop: 24 ± 0.4 mm Hg; p < 0.05) and hemoglobin concentration were significantly decreased after bolus fluid administration.

CONCLUSIONS

We define efficacy of decision-assist and closed-loop resuscitation in human hemorrhage. In comparison with formula-based bolus resuscitation, both semiautonomous and autonomous approaches were more efficient in goal-directed resuscitation of hemorrhage. They provide favorable conditions for the avoidance of over-resuscitation and its adverse clinical sequelae. Decision-assist and closed-loop resuscitation algorithms are promising technological solutions for constrained environments and areas of limited resources.

Changes in Radial Artery Pulse Pressure During a Fluid Challenge Cannot Assess Fluid Responsiveness in Patients With Septic Shock

BACKGROUND

Arterial blood pressure is the most common variable used to assess the response to a fluid challenge in routine clinical practice. The aim of this study was to evaluate the accuracy of the change in the radial artery pulse pressure (rPP) to detect the change in cardiac output after a fluid challenge in patients with septic shock.

METHODS

Prospective observational study including 35 patients with septic shock in which rPP and cardiac output were measured before and after a fluid challenge with 400 mL of crystalloid solution. Cardiac output was measured with intermittent thermodilution technique using a pulmonary artery catheter. Patients were divided between responders (increase >15% of cardiac output after fluid challenge) and nonresponders. The area under the receiver operating characteristic curve (AUROC), Pearson correlation coefficient and paired Student t test were used in statistical analysis.

RESULTS

Forty-three percent of the patients were fluid responders. The change in rPP could not neither discriminate between responders and nonresponders (AUROC = 0.52; [95% confidence interval: 0.31-0.72] P = .8) nor correlate (r = .21, P = .1) with the change in cardiac output after the fluid challenge.

CONCLUSIONS

The change in rPP neither discriminated between fluid responders and nonresponders nor correlated with the change in cardiac output after a fluid challenge. The change in rPP cannot serve as a surrogate of the change in cardiac output to assess the response to a fluid challenge in patients with septic shock.

Postoperative acute kidney injury in living donor liver transplantation recipients

PURPOSE

There are many risk factors for postoperative acute kidney injury in liver transplantation. The aim of this study is to investigate the risk factors for postoperative acute kidney injury in living donor liver transplantation recipients.

METHODS

220 living donor liver transplantation recipients were retrospectively evaluated in the study. According to the Kidney Disease Improving Global Outcomes Guidelines, acute kidney injury in postoperative day 7 was investigated for all patients. The patient's demographic data, preoperative and intraoperative parameters, and outcomes were recorded.

RESULTS

Acute kidney injury was found in 27 (12.3%) recipients. In recipients with acute kidney injury, female population, model for end-stage liver disease score, norepinephrine requirement, duration of mean arterial pressure less than 60 mmHg, the usage of gelatin and erythrocyte suspension and blood loss were significantly higher than recipients with nonacute kidney injury (for all p<0.05). In multivariate analyses, the likelihood of acute kidney injury on postoperative day 7 were increased 2.8-fold (1.1-7.0), 2.7-fold (1.02-7.3), 3.4-fold (1.2-9.9) and 5.1-fold (1.7-15.0) by postoperative day 7, serum tacrolimus level ≥10.2 ng dL-1, intraoperative blood loss ≥14.5 mL kg-1, the usage of gelatin >5 mL kg-1 and duration of MAP less than 60 mmHg ≥5.5 minutes respectively (for all p<0.05).

CONCLUSIONS

In living donor liver transplantation recipients, serum tacrolimus levels, intraoperative blood loss, hypotension period and the usage of gelatin may be risk factors for acute kidney injury in the early postoperative period.

Prophylactic plasma transfusion for patients undergoing non-cardiac surgery

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To determine the clinical effectiveness and safety of prophylactic plasma transfusion for people with confirmed or presumed coagulopathy requiring non-cardiac surgery.

Passive Leg Raising: Simple and Reliable Technique to Prevent Fluid Overload in Critically ill Patients

Background:

Dynamic measures, the response to stroke volume (SV) to fluid loading, have been used successfully to guide fluid management decisions in critically ill patients. However, application of dynamic measures is often inaccurate to predict fluid responsiveness in patients with arrhythmias, ventricular dysfunction or spontaneously breathing critically ill patients. Passive leg raising (PLR) is a simple bedside maneuver that may provide an accurate alternative to guide fluid resuscitation in hypovolemic critically ill patients.

Methods:

Pertinent medical literature for fluid responsiveness in the critically ill patient published in English was searched over the past three decades, and then the search was extended as linked citations indicated.

Results:

Thirty-three studies including observational studies, randomized control trials, systemic review, and meta-analysis studies evaluating fluid responsiveness in the critically ill patient met selection criteria.

Conclusions:

PLR coupled with real-time SV monitors is considered a simple, noninvasive, and accurate method to determine fluid responsiveness in critically ill patients with high sensitivity and specificity for a 10% increase in SV. The adverse effect of albumin on the mortality of head trauma patients and chloride-rich crystalloids on mortality and kidney function needs to be considered when choosing the type of fluid for resuscitation.

Fluid Resuscitation: Principles of Therapy and "Kidney Safe" Considerations

Fluid resuscitation in the acutely ill must take into consideration numerous elements, including the intravenous solution itself, the phase of resuscitation, and the strategies toward volume management which are paramount. With the advancement in the understanding and implementation of aggressive fluid resuscitation has also come a greater awareness of the resultant fluid toxicity, especially in those that suffer acute kidney injury, and the realization that there is continued ambiguity with regard to volume mitigation and removal in the resuscitated patient. As such, the discussion regarding intravenous solutions continues to evolve especially as it pertains to their effect on kidney and metabolic function, electrolytes, and ultimately patient outcome. In the section below, we review the foundations of fluid resuscitation in the critically ill patient and the different solutions available in this context, including their composition, physiologic properties, and safety and efficacy including the available data regarding "renal-safe" options.

Low-volume resuscitation with normal saline is associated with microvascular endothelial dysfunction after hemorrhage in rats, compared to colloids and balanced crystalloids

Background

Restoration of endothelial glycocalyx (EG) barrier may be an essential therapeutic target for successful resuscitation. The aim of this study was to compare in vivo the effects of resuscitation with normal saline (NS) to lactated Ringer’s solution (LR), 5% albumin and fresh frozen plasma (FFP) on their ability to maintain EG and barrier function integrity, mitigate endothelial injury and inflammation, and restore vascular homeostasis after hemorrhagic shock.

Methods

Anesthetized rats (N = 36) were subjected to hemorrhagic shock (bled 40% of total blood volume), followed by resuscitation with 45 ml/kg NS or LR, or 15 ml/kg 5% albumin or FFP. Microhemodynamics, EG thickness, permeability, leukocyte rolling and adhesion were assessed in >180 vessels from cremaster muscle, as well as systemic measures.

Results

After hypotensive resuscitation, arterial pressure was 25% lower than baseline in all cohorts. Unlike FFP, resuscitation with crystalloids failed to restore EG thickness to baseline post shock and shedding of glycocalyx proteoglycan was significantly higher after NS. NS decreased blood flow and shear, and markedly increased permeability and leukocyte rolling/adhesion. In contrast, LR had lesser effects on increased permeability and leukocyte rolling. Albumin stabilized permeability and white blood cell (WBC) rolling/adhesion post shock, comparable to FFP.

Conclusions

Resuscitation with NS failed to inhibit syndecan-1 shedding and to repair the EG, which led to loss of endothelial barrier function (edema), decline in tissue perfusion and pronounced leukocyte rolling and adhesion. Detrimental effects of NS on endothelial and microvascular stabilization post shock may provide a pathophysiological basis to understand and prevent morbidity associated with iatrogenic resuscitation after hemorrhagic shock.

Strategies for Intravenous Fluid Resuscitation in Trauma Patients

Intravenous fluid management of trauma patients is fraught with complex decisions that are often complicated by coagulopathy and blood loss. This review discusses the fluid management in trauma patients from the perspective of the developing world. In addition, the article describes an approach to specific circumstances in trauma fluid decision-making and provides recommendations for the resource-limited environment.

Severe Snakebite Envenoming in Intensive Care

Snakebites by exotic venomous snakes can cause serious or even life-threatening envenoming. In Europe and North America most victims are breeders, with a few snakebites from wild native American rattlesnakes. The envenomed victims may present in organ and/or system failure with muscle paralysis, respiratory failure, circulatory instability, acute kidney injury, severe coagulation disorder, and local disability - compartment syndrome and necrosis. Best managed by close collaboration between clinical toxicology and intensive care, most severe envenomings are managed primarily by intensive care physicians. Due to the low incidence of severe envenoming, the clinical course and correct management of these cases are not intrinsically familiar to most physicians. This review article summarizes the clinical syndromes caused by severe envenoming and the therapeutic options available in the intensive care setting.

Use of intravenous fluids/solutions: a narrative review

OBJECTIVE

Intravenous fluids are broadly categorized into colloids and crystalloids. The aim of this review is to present under a clinical point of view the characteristics of intravenous fluids that make them more or less appropriate either for maintaining hydration when enteral intake is contraindicated or for treating hypovolemia.

METHODS

We considered randomized trials and meta-analyses as well as narrative reviews evaluating the effects of colloids or crystalloids in patients with hypovolemia or as maintenance fluids published in the PubMed and Cochrane databases.

RESULTS

Clinical studies have not shown a greater clinical benefit of albumin solutions compared with crystalloid solutions. Furthermore, albumin and colloid solutions may impair renal function, while there is no evidence that the administration of colloids reduces the risk of death compared with resuscitation with crystalloids in patients with trauma, burns or following surgery. Among crystalloids, normal saline is associated with the development of hyperchloremia-induced impairment of kidney function and metabolic acidosis. On the other hand, the other commonly used crystalloid solution, the Ringer's Lactate, has certain indications and contraindications. These matters, along with the basic principles of the administration of potassium chloride and bicarbonate, are meticulously discussed in the review.

CONCLUSIONS

Intravenous fluids should be dealt with as drugs, as they have specific clinical indications, contraindications and adverse effects.

Intravenous Fluids in AKI: A Mechanistically Guided Approach

Acute kidney injury (AKI) has been associated with an increased risk of death and morbidity in many clinical scenarios. The prevention and treatment of AKI therefore has been advocated as a high-priority research focus. However, nearly all strategies tested in this setting have failed to prevent or cure AKI and fluid loading remains a cornerstone of preventive and curative treatment of AKI. Concerns have been raised, however, regarding both the efficacy and safety of fluid loading to prevent or reverse AKI. In this review, we address the question of the best use of fluid loading based on current preclinical and clinical data in a mechanistically guided approach. Impacts of fluid resuscitation on renal hemodynamics, from macrocirculation to microcirculation, with physiological end points as well as renal consequences of different fluids available are discussed. Finally, the complex relationship between renal hemodynamics is discussed.

Prediction of fluid responsiveness: an update

In patients with acute circulatory failure, the decision to give fluids or not should not be taken lightly. The risk of overzealous fluid administration has been clearly established. Moreover, volume expansion does not always increase cardiac output as one expects. Thus, after the very initial phase and/or if fluid losses are not obvious, predicting fluid responsiveness should be the first step of fluid strategy. For this purpose, the central venous pressure as well as other “static” markers of preload has been used for decades, but they are not reliable. Robust evidence suggests that this traditional use should be abandoned. Over the last 15 years, a number of dynamic tests have been developed. These tests are based on the principle of inducing short-term changes in cardiac preload, using heart–lung interactions, the passive leg raise or by the infusion of small volumes of fluid, and to observe the resulting effect on cardiac output. Pulse pressure and stroke volume variations were first developed, but they are reliable only under strict conditions. The variations in vena caval diameters share many limitations of pulse pressure variations. The passive leg-raising test is now supported by solid evidence and is more frequently used. More recently, the end-expiratory occlusion test has been described, which is easily performed in ventilated patients. Unlike the traditional fluid challenge, these dynamic tests do not lead to fluid overload. The dynamic tests are complementary, and clinicians should choose between them based on the status of the patient and the cardiac output monitoring technique. Several methods and tests are currently available to identify preload responsiveness. All have some limitations, but they are frequently complementary. Along with elements indicating the risk of fluid administration, they should help clinicians to take the decision to administer fluids or not in a reasoned way.