Feasibility of Goal-Directed Fluid Therapy in Patients with Transcatheter Aortic Valve Replacement - An Ambispective Analysis.

INTRODUCTION: Goal-directed fluid therapy (GDFT) has been shown to reduce postoperative complications. The feasibility of GDFT in transcatheter aortic valve replacement (TAVR) patients under general anesthesia has not yet been demonstrated. We examined whether GDFT could be applied in patients undergoing TAVR in general anesthesia and its impact on outcomes. METHODS: Forty consecutive TAVR patients in the prospective intervention group with GDFT were compared to 40 retrospective TAVR patients without GDFT. Inclusion criteria were age ≥ 18 years, elective TAVR in general anesthesia, no participation in another interventional study. Exclusion criteria were lack of ability to consent study participation, pregnant or nursing patients, emergency procedures, preinterventional decubitus, tissue and/or extremity ischemia, peripheral arterial occlusive disease grade IV, atrial fibrillation or other severe heart rhythm disorder, necessity of usage of intra-aortic balloon pump. Stroke volume and stroke volume variation were determined with uncalibrated pulse contour analysis and optimized according to a predefined algorithm using 250 ml of hydroxyethyl starch. RESULTS: Stroke volume could be increased by applying GDFT. The intervention group received more colloids and fewer crystalloids than control group. Total volume replacement did not differ. The incidence of overall complications as well as intensive care unit and hospital length of stay were comparable between both groups. GDFT was associated with a reduced incidence of delirium. Duration of anesthesia was shorter in the intervention group. Duration of the interventional procedure did not differ. CONCLUSION: GDFT in the intervention group was associated with a reduced incidence of postinterventional delirium.

Effect of different targets of goal-directed fluid therapy on intraoperative hypotension and fluid infusion in robot-assisted laparoscopic gynecological surgery: a randomized non-inferiority trial.

Carotid corrected flow time (FTc) and tidal volume challenge pulse pressure variation (VtPPV) are useful clinical parameters for assessing volume status and fluid responsiveness in robot-assisted surgery, but their usefulness as goal-directed fluid therapy (GDFT) targets is unclear. We investigated whether FTc or VtPPV as targets are inferior to PPV in GDFT. This single-center, prospective, randomized, non-inferiority study included 133 women undergoing robot-assisted laparoscopic gynecological surgery in the modified head-down lithotomy position. Patients were equally divided into three groups, and the GDFT protocol was guided by FTc, VtPPV, or PPV during surgery. Primary outcomes were non-inferiority of the time-weighted average of hypotension, intraoperative fluid volume, and urine output. Secondary outcomes were optic nerve sheath diameter (ONSD) pre- and post-operatively and creatinine and blood urea nitrogen preoperatively and on day 1 post-operatively. No significant differences were observed in intraoperative hypotension index, infusion and urine volumes, and ONSD post-operatively between the FTc and VtPPV groups and the PPV group. No differences in serum creatinine and urea nitrogen levels were identified between the FTc and VtPPV groups preoperatively, but on day 1 post-operatively, the urea nitrogen level in the FTc group was higher than that in the PPV group (4.09 ± 1.28 vs. 3.0 ± 1.1 mmol/L, 1.08 [0.59, 1.58], p < 0.0001), and the difference from the preoperative value was smaller than that in the PPV group (- 2 [- 2.97, 1.43] vs. - 1.34 [- 1.9, - 0.67], p = 0.004). FTc- or VtPPV-guided protocols are not inferior to that of PPV in GDFT during robot-assisted laparoscopic surgery in the modified head-down lithotomy position.Trial registration: Chinese Clinical Trial Registry (ChiCTR2200064419).

Evaluating the efficacy of different volume resuscitation strategies in acute pancreatitis patients: a systematic review and meta-analysis.

INTRODUCTION: Acute pancreatitis poses a significant health risk due to the potential for pancreatic necrosis and multi-organ failure. Fluid resuscitation has demonstrated positive effects; however, consensus on the ideal intravenous fluid type and infusion rate for optimal patient outcomes remains elusive. METHODS: A comprehensive literature search was conducted using PubMed, Embase, the Cochrane Library, Scopus, and Google Scholar for studies published between 2005 and January 2023. Reference lists of potential studies were manually searched to identify additional relevant articles. Randomized controlled trials and retrospective studies comparing high (≥ 20 ml/kg/h), moderate (≥ 10 to < 20 ml/kg/h), and low (5 to < 10 ml/kg/h) fluid therapy in acute pancreatitis were considered. RESULTS: Twelve studies met our inclusion criteria. Results indicated improved clinical outcomes with low versus moderate fluid therapy (OR = 0.73; 95% CI [0.13, 4.03]; p = 0.71) but higher mortality rates with low compared to moderate (OR = 0.80; 95% CI [0.37, 1.70]; p = 0.55), moderate compared to high (OR = 0.58; 95% CI [0.41, 0.81], p = 0.001), and low compared to high fluids (OR = 0.42; 95% CI [0.16, 1.10]; P = 0.08). Systematic complications improved with moderate versus low fluid therapy (OR = 1.22; 95% CI [0.84, 1.78]; p = 0.29), but no difference was found between moderate and high fluid therapy (OR = 0.59; 95% CI [0.41, 0.86]; p = 0.006). DISCUSSION: This meta-analysis revealed differences in the clinical outcomes of patients with AP receiving low, moderate, and high fluid resuscitation. Low fluid infusion demonstrated better clinical outcomes but higher mortality, systemic complications, and SIRS persistence than moderate or high fluid therapy. Early fluid administration yielded better results than rapid fluid resuscitation.

Comparison of Dynamic Measures in Intraoperative Goal-Directed Fluid Therapy of Patients with Morbid Obesity Undergoing Laparoscopic Sleeve Gastrectomy.

INTRODUCTION: Obesity increases the risk of morbidity and mortality during surgical procedures. Goal-directed fluid therapy (GDFT) is a new concept for perioperative fluid management that has been shown to improve patient prognosis. This study aimed to investigate the role of the Pleth Variability Index (PVI), systolic pressure variation (SPV), and pulse pressure variation (PPV) in maintaining tissue perfusion and renal function during GDFT management in patients undergoing laparoscopic sleeve gastrectomy (LSG). MATERIALS AND METHODS: Two hundred ten patients were enrolled in our prospective randomized controlled clinical trial. Demographic data, hemodynamic parameters, biochemical parameters, the amount of crystalloid and colloid fluid administered intraoperatively, and the technique of goal-directed fluid management used were recorded. Patients were randomly divided into three groups: PVI (n = 70), PPV (n = 70), and SPV (n = 70), according to the technique of goal-directed fluid management. Postoperative nausea and vomiting, time of return of bowel movement, and hospital stay duration were recorded. RESULTS: There was no statistically significant difference between the number of crystalloids administered in all three groups. However, the amount of colloid administered was statistically significantly lower in the SPV group than in the PVI group, and there was no significant difference in the other groups. Statistically, there was no significant difference between the groups in plasma lactate, blood urea, and creatinine levels. CONCLUSION: In LSG, dynamic measurement techniques such as PVI, SPV, and PPV can be used in patients with morbid obesity without causing intraoperative and postoperative complications. PVI may be preferred over other invasive methods because it is noninvasive.

Easy method to determine fluid responsiveness in septic shock patients: end-tidal CO2 - a prospective observational study.

BACKGROUND: In critically ill patients, especially those with septic shock, fluid management can be a challenging aspect of clinical care. One of the primary steps in treating patients with hemodynamic instability is optimizing intravascular volume. The Passive Leg Raising (PLR) maneuver is a reliable test for assessing fluid responsiveness, as demonstrated by numerous studies and meta-analyses. However, its use requires the measurement of cardiac output, which is often complex and may necessitate clinician experience and specialized equipment. End-Tidal Carbon Dioxide (ETCO2) measurement is relatively easy and is generally stable under steady metabolic conditions. It depends on the body's CO2 production, diffusion of CO2 from the lungs into the bloodstream, and cardiac output. If the other two parameters (metabolic conditions and minute ventilation) are constant, ETCO2 can provide information about cardiac output. The aim of the present study is to investigate the sensitivity of ETCO2 measurement in demonstrating fluid responsiveness. METHODS: All patients diagnosed with septic shock and meeting the inclusion criteria were subjected to a passive leg raising test, and cardiac outputs were measured by echocardiography. An increase in cardiac output of 15% or more was considered indicative of the fluid responder group, while patients with an increase below 15% or no increase were classified as the non-responder group. Patients' intensive care unit admission diagnoses, initial laboratory parameters, tidal volume, minute volume before and after the PLR maneuver, mean and systolic blood pressure, heart rate, Pulse Pressure Variation (PPV) values, and ETCO2 values were recorded. RESULTS: Before and after the ETCO2 test, there was no statistically significant difference between the two groups. However, the change in ETCO2 (ΔETCO2) was significantly higher in the responder group. In the non-responder group, ΔETCO2 was 2.57% (0.81), whereas it was 5.71% (2.83) in the responder group (p<0.001). Receiver Operating Characteristic (ROC) analysis was performed for ΔETCO2, baseline Stroke Volume Variation (SVV), ΔSVV, baseline Heart Rate (HR), ΔHR, baseline PPV, and ΔPPV to predict fluid responsiveness. ΔETCO2 predicted fluid responsiveness with a sensitivity of 85% and a specificity of 86% when it was 4% or higher. When ΔETCO2 was 5% or higher, it predicted fluid responsiveness with a specificity of 99.3% and a sensitivity of 75.5%, with an Area Under the Curve (AUC) of 0.89 (95% confidence interval, 0.828-0.961). CONCLUSION: This study demonstrates that in septic patients, ETCO2 during the PLR test can indicate fluid responsiveness with high sensitivity and specificity and can be used as an alternative to cardiac output measurement.

The impact of goal-directed fluid therapy on postoperative pulmonary complications in patients undergoing thoracic surgery: a systematic review and meta-analysis.

BACKGROUND: Pulmonary complications after thoracic surgery are common and associated with significant morbidity and high cost of care. Goal-directed fluid therapy (GDFT) could reduce the incidence of postoperative pulmonary complications (PPCs) and facilitate recovery in patients undergoing major abdominal surgery. However, whether GDFT could reduce the incidence of PPCs in patients undergoing thoracic surgery was unclear. The present meta-analysis was designed to assess the impact of Goal-directed Fluid Therapy on PPCs in patients undergoing thoracic surgery. METHODS: Randomized controlled trials (RCTs) comparing GDFT with other conventional fluid management strategies in adult patients undergoing thoracic surgery were identified. Databases searched included PubMed, Web of Science, Embase, and Cochrane Library databases. Review Manager 5.4 (The Cochrane Collaboration, Oxford, UK) software was used for statistical analysis. Heterogeneity was analyzed using I2 statistics, and a standardized mean difference with 95% CI and P value was used to calculate the treatment effect for outcome variables. The primary study outcomes were the incidence of PPCs. Secondary outcomes were the total volume infused, the length of hospitalization, the incidence of cardiac complications, and the incidence of renal dysfunction. Subgroup analysis was planned to verify the definite role of GDFT. RESULTS: A total of 6 RCTs consisting of 680 patients were included in this meta-analysis, which revealed that GDFT did not reduce the incidence of PPCs in patients undergoing thoracic surgery (RR, 0.57; 95% CI 0.29-1.14). However, GDFT decreased the total intra-operative fluid input (MD, - 244.40 ml; 95% CI - 397.06 to - 91.74). There was no statistical difference in the duration of hospitalization (MD; - 1.31, 95% CI - 3.00 to 0.38), incidence of renal dysfunction (RR, 0.62; 95% CI 0.29-1.35), and incidence of cardiac complications (RR, 0.62; 95% CI 0.27-1.40). CONCLUSIONS: The results of this meta-analysis indicate that GDFT did not reduce the postoperative incidence of pulmonary complications in individuals undergoing thoracic surgery. However, considering the small number of contributing studies, these results should be interpreted with caution.

Faster discharge with lactated ringers than normal saline in first 72 h of acute pancreatitis: A multicenter randomized trial.

OBJECTIVES: Data driven strategies for acute pancreatitis (AP) in pediatrics are limited; adult data suggests lactated ringers (LR) compared to normal saline (NS) resulted in favorable outcomes, but has not been studied in pediatrics. Our objective was to evaluate the efficacy of LR during the first 48 h of an AP episode compared with NS. STUDY DESIGN: A multisite randomized controlled clinical trial, from 2015 to 2020 (Clinical Trials.gov NCT03242473). Patients were randomized to exclusively LR or NS for the first 48 h. Primary outcomes were serial C-reactive protein (CRP) values. Secondary outcomes included other lab values, time to feeds, length of stay (LOS), systemic inflammatory response syndrome (SIRS) development, and progression to severe AP (SAP). RESULTS: We studied 76 patients (38 LR, 38 NS). CRP at 24 and 48 h were not significantly different between LR or NS group. Additionally, there were no differences in trends of BUN, amylase, lipase, SIRS status, or SAP development between the LR and NS group at 24 and 48 h. A higher proportion of LR patients (32%, 12/38) were discharged before 48 h compared to NS (13%, 5/38). The LR group had a significantly higher rate of discharge within the first 72 h compared to the NS group (p = 0.02). CONCLUSION: The use of LR was associated with a faster rate of discharge during the intervention period and in the first 72 h, but no other differences compared to NS. This reduction in length of hospitalization has significant implications for patients and healthcare costs.

Use of inferior vena cava guided fluid therapy in the treatment of septic shock: A randomised controlled trial.

INTRODUCTION: By administering inferior vena cava (IVC) directed fluid, it is possible to avoid the use of additional fluid and fluid overload in patients with septic shock (SS) and sepsis-induced hypoperfusion (SIH). METHODOLOGY: In patients with SIH and SS, we conducted prospective observational research on fluid therapy. A time-motion trace of the IVC diameter was created using M-mode imaging. The ability to predict fluid responsiveness was based on the IVC collapsibility index (cIVC) > 40%. Participants were randomised into 2 groups using a permuted block-of-four randomization list, with the investigators being blinded prior to patient allocation. They were split equally between the usual-care (UC) group, which received sepsis-guided fluid treatment, and the interventional ultrasound-guided fluid therapy (UGFT) group. RESULTS: The average age of the participants was 63.2 years (62.8 years for the UGFT group and 63.7 years for the UC group). Co-morbid health conditions were practically the same in both arms at baseline. Prior to enrolment, both groups received the same quantity of fluid as part of resuscitation (UGFT arm received 2.4 0.6 L, UC group received 2.2 0.7 L). The UGFT group outperformed the UC group with a P value of 0.02 due to a significantly lower positive fluid balance after 72 hours of ICU discharge (-1.37 L), which rendered the UGFT group superior to the UC group. Even after accounting for the fluids consumed before enrolment, there was still a sizable difference in the fluids infused. When the pre-enrolment fluids were counted at 72 hours, UGFT participants still displayed a decreased positive fluid balance. However, there was no discernible difference in the 30-day mortality rate overall (6.3% difference, UGFT: 15.7%, and UC: 22.0%). CONCLUSIONS: In contrast to the UC group, the UGFT arm of our study demonstrated a statistically significant benefit of Point of Care USG (POCUS) guided fluid therapy during resuscitation in sepsis in reducing the positive fluid balance in 72 hours, preventing fluid overload, and reducing the need for dialysis and invasive ventilation. However, there was no statistically significant variation in the 30-day mortality rate.

Revised one-bag IV fluid protocol for pediatric DKA: a feasible approach and retrospective comparative study.

BACKGROUND: This study compared the effectiveness of the traditional and revised one-bag protocols for pediatric diabetic ketoacidosis (DKA) management. METHODS: This single-center retrospective cohort study included children diagnosed with DKA upon admission between 2012 and 2019. Our institution reevaluated and streamlined the traditional one-bag protocol (revised one-bag protocol). The revised one-bag protocol rehydrated all pediatric DKA patients with dextrose (5 g/100 ml) containing 0.45% NaCl at a rate of 3500 ml/m2 per 24 h after the first 1 h bolus of normal saline, regardless of age or degree of dehydration. This study examined acidosis recovery times and the frequency of healthcare provider interventions to maintain stable blood glucose levels. RESULTS: The revised one-bag protocol demonstrated a significantly shorter time to acidosis recovery than the traditional protocol (12.67 and 18.20 h, respectively; p < 0.001). The revised protocol group required fewer interventions for blood glucose control, with an average of 0.25 dextrose concentration change orders per patient, compared to 1.42 in the traditional protocol group (p < 0.001). Insulin rate adjustments were fewer in the revised protocol group, averaging 0.52 changes per patient, vs. 2.32 changes in the traditional protocol group (p < 0.001). CONCLUSION: The revised one-bag protocol for pediatric DKA is both practical and effective. This modified DKA management achieved acidosis recovery more quickly and reduced blood glucose fluctuations compared with the traditional one-bag protocol. Future studies, including randomized controlled trials, should assess the safety and effectiveness of the revised protocol in a broad range of pediatric patients with DKA.

Dynamic monitoring tools for patients admitted to the emergency department with circulatory failure: narrative review with panel-based recommendations.

Intravenous fluid therapy is commonly administered in the emergency department (ED). Despite the deleterious potential of over- and under-resuscitation, professional society guidelines continue to recommend administering a fixed volume of fluid in initial resuscitation. Predicting whether a specific patient will respond to fluid therapy remains one of the most important, but challenging questions that ED clinicians face in clinical practice. Surrogate parameters (i.e. blood pressure and heart rate), are widely used in usual care to estimate changes in stroke volume (SV). Due to their inadequacy in estimating SV, noninvasive techniques (e.g. bioreactance, echocardiography, noninvasive finger cuff technology), have been proposed as a more accurate and readily deployable method for assessing flow and preload responsiveness. Dynamic monitoring systems based on cardiac preload challenge and assessment of SV, by using noninvasive and continuous methods, provide more accurate, feasible, efficient, and reasonably accurate strategy for prediction of fluid responsiveness than static measurements. In this article, we aimed to analyze the different methods currently available for dynamic monitoring of preload responsiveness.

Coexistence of a fluid responsive state and venous congestion signals in critically ill patients: a multicenter observational proof-of-concept study.

BACKGROUND: Current recommendations support guiding fluid resuscitation through the assessment of fluid responsiveness. Recently, the concept of fluid tolerance and the prevention of venous congestion (VC) have emerged as relevant aspects to be considered to avoid potentially deleterious side effects of fluid resuscitation. However, there is paucity of data on the relationship of fluid responsiveness and VC. This study aims to compare the prevalence of venous congestion in fluid responsive and fluid unresponsive critically ill patients after intensive care (ICU) admission. METHODS: Multicenter, prospective cross-sectional observational study conducted in three medical-surgical ICUs in Chile. Consecutive mechanically ventilated patients that required vasopressors and admitted < 24 h to ICU were included between November 2022 and June 2023. Patients were assessed simultaneously for fluid responsiveness and VC at a single timepoint. Fluid responsiveness status, VC signals such as central venous pressure, estimation of left ventricular filling pressures, lung, and abdominal ultrasound congestion indexes and relevant clinical data were collected. RESULTS: Ninety patients were included. Median age was 63 [45-71] years old, and median SOFA score was 9 [7-11]. Thirty-eight percent of the patients were fluid responsive (FR+), while 62% were fluid unresponsive (FR-). The most prevalent diagnosis was sepsis (41%) followed by respiratory failure (22%). The prevalence of at least one VC signal was not significantly different between FR+ and FR- groups (53% vs. 57%, p = 0.69), as well as the proportion of patients with 2 or 3 VC signals (15% vs. 21%, p = 0.4). We found no association between fluid balance, CRT status, or diagnostic group and the presence of VC signals. CONCLUSIONS: Venous congestion signals were prevalent in both fluid responsive and unresponsive critically ill patients. The presence of venous congestion was not associated with fluid balance or diagnostic group. Further studies should assess the clinical relevance of these results and their potential impact on resuscitation and monitoring practices.

Resuscitation With Early Adrenaline Infusion for Children With Septic Shock: A Randomized Pilot Trial.

OBJECTIVES: In children with septic shock, guidelines recommend resuscitation with 40-60 mL/kg of fluid boluses, yet there is a lack of evidence to support this practice. We aimed to determine the feasibility of a randomized trial comparing early adrenaline infusion with standard fluid resuscitation in children with septic shock. DESIGN: Open-label parallel randomized controlled, multicenter pilot study. The primary end point was feasibility; the exploratory clinical endpoint was survival free of organ dysfunction by 28 days. SETTING: Four pediatric Emergency Departments in Queensland, Australia. PATIENTS: Children between 28 days and 18 years old with septic shock. INTERVENTIONS: Patients were assigned 1:1 to receive a continuous adrenaline infusion after 20 mL/kg fluid bolus resuscitation (n = 17), or standard care fluid resuscitation defined as delivery of 40 to 60 mL/kg fluid bolus resuscitation prior to inotrope commencement (n = 23). MEASUREMENTS AND MAIN RESULTS: Forty of 58 eligible patients (69%) were consented with a median age of 3.7 years (interquartile range [IQR], 0.9-12.1 yr). The median time from randomization to inotropes was 16 minutes (IQR, 12-26 min) in the intervention group, and 49 minutes (IQR, 29-63 min) in the standard care group. The median amount of fluid delivered during the first 24 hours was 0 mL/kg (IQR, 0-10.0 mL/kg) in the intervention group, and 20.0 mL/kg (14.6-28.6 mL/kg) in the standard group (difference, -20.0; 95% CI, -28.0 to -12.0). The number of days alive and free of organ dysfunction did not differ between the intervention and standard care groups, with a median of 27 days (IQR, 26-27 d) versus 26 days (IQR, 25-27 d). There were no adverse events reported associated with the intervention. CONCLUSIONS: In children with septic shock, a protocol comparing early administration of adrenaline versus standard care achieved separation between the study arms in relation to inotrope and fluid bolus use.

The Use of Intraosseous Infusion in the Early Resuscitation of Patients With Extremely Severe Burns.

According to research, shock, the most common complication of extremely severe burns, is also the leading cause of mortality among patients with such burns. The case fatality rate reaches 83.45% when the total burn area exceeds 90%. The American Heart Association in 2020 recommended the intraosseous (IO) access after the peripheral access and prior to the central venous access when venous cannulation is either difficult or delayed. The use and experience with intraosseous infusion in extremely severe burns are still limited. We report efficacy and safety results from 19 burn patients treated with IO infusion between June 2020 and December 2022. In these patients, the mean injury time of burns was 1.55 ± 1.10 hours, the mean burn surface area was 86.24% ± 11.33%, the mean catheterization time was 49.68 ± 10.11 seconds, and the mean emergency retention time was 2.75 ± 1.74 hours, the mean actual fluid supplement amount was 5,533.68 ± 3,077.19 mL, the mean hourly urine volume of the patient was 93.31 ± 60.94 mL, the mean emergency detention time was 4.16 ± 2.97 hours, and the mean duration of hospitalization was 34.50 ± 25.38 days. The results demonstrated a clinically meaningful improvement and higher response rate vs peripheral venous cannulation and an acceptable safety profile in those patients.

Perioperative Fluid and Vasopressor Therapy in 2050: From Experimental Medicine to Personalization Through Automation.

Intravenous (IV) fluids and vasopressor agents are key components of hemodynamic management. Since their introduction, their use in the perioperative setting has continued to evolve, and we are now on the brink of automated administration. IV fluid therapy was first described in Scotland during the 1832 cholera epidemic, when pioneers in medicine saved critically ill patients dying from hypovolemic shock. However, widespread use of IV fluids only began in the 20th century. Epinephrine was discovered and purified in the United States at the end of the 19th century, but its short half-life limited its implementation into patient care. Advances in venous access, including the introduction of the central venous catheter, and the ability to administer continuous infusions of fluids and vasopressors rather than just boluses, facilitated the use of fluids and adrenergic agents. With the advent of advanced hemodynamic monitoring, most notably the pulmonary artery catheter, the role of fluids and vasopressors in the maintenance of tissue oxygenation through adequate cardiac output and perfusion pressure became more clearly established, and hemodynamic goals could be established to better titrate fluid and vasopressor therapy. Less invasive hemodynamic monitoring techniques, using echography, pulse contour analysis, and heart-lung interactions, have facilitated hemodynamic monitoring at the bedside. Most recently, advances have been made in closed-loop fluid and vasopressor therapy, which apply computer assistance to interpret hemodynamic variables and therapy. Development and increased use of artificial intelligence will likely represent a major step toward fully automated hemodynamic management in the perioperative environment in the near future. In this narrative review, we discuss the key events in experimental medicine that have led to the current status of fluid and vasopressor therapies and describe the potential benefits that future automation has to offer.

Nurse-Driven Fluid Responsiveness Evaluation in Patients With Septic Shock: A Quality Improvement Initiative.

BACKGROUND: Fluid responsiveness should be assessed in patients with septic shock because only 50% of patients are fluid responsive. Dynamic measures of fluid responsiveness, like pulse pressure variation measured after a passive leg raise maneuver, are recommended to guide fluid administration in patients with sepsis after initial fluid resuscitation. LOCAL PROBLEM: The purpose of the project was to evaluate outcomes after implementing a nurse-driven fluid responsiveness evaluation using passive leg raise and pulse pressure variation measurement in patients with septic shock. METHODS: The project included 30 adult patients with septic shock in a 24-bed medical-surgical intensive care unit at a community hospital. A new nursing process was initiated for bedside fluid responsiveness evaluation (pulse pressure variation measurement after passive leg raise). Staff members received in-person individual training sessions. Preintervention and 20-week postintervention patient outcomes data were collected to estimate the project's impact on incidence of fluid overload and acute kidney injury, duration of mechanical ventilation, and intensive care unit length of stay. Preintervention and postintervention staff satisfaction surveys assessed nurses' perception of the project's value. RESULTS: Before intervention, 24 of 37 patients (65%) met criteria of fluid overload. The project resulted in a 28% decrease in the incidence of fluid overload. Staff satisfaction surveys revealed a significant increase in nurses' feelings of empowerment to positively affect patient outcomes; all nurses agreed that the new process was efficient. CONCLUSION: The results indicate that the project had a positive impact on patient outcomes and nurse autonomy.

Goal-directed colloid versus crystalloid therapy and microcirculatory blood flow following ischemia/reperfusion.

OBJECTIVE: Ischemia/reperfusion can impair microcirculatory blood flow. It remains unknown whether colloids are superior to crystalloids for restoration of microcirculatory blood flow during ischemia/reperfusion injury. We tested the hypothesis that goal-directed colloid - compared to crystalloid - therapy improves small intestinal, renal, and hepatic microcirculatory blood flow in pigs with ischemia/reperfusion injury. METHODS: This was a randomized trial in 32 pigs. We induced ischemia/reperfusion by supra-celiac aortic-cross-clamping. Pigs were randomized to receive either goal-directed isooncotic hydroxyethyl-starch colloid or balanced isotonic crystalloid therapy. Microcirculatory blood flow was measured using Laser-Speckle-Contrast-Imaging. The primary outcome was small intestinal, renal, and hepatic microcirculatory blood flow 4.5 h after ischemia/reperfusion. Secondary outcomes included small intestinal, renal, and hepatic histopathological damage, macrohemodynamic and metabolic variables, as well as specific biomarkers of tissue injury, renal, and hepatic function and injury, and endothelial barrier function. RESULTS: Small intestinal microcirculatory blood flow was higher in pigs assigned to isooncotic hydroxyethyl-starch colloid therapy than in pigs assigned to balanced isotonic crystalloid therapy (768.7 (677.2-860.1) vs. 595.6 (496.3-694.8) arbitrary units, p = .007). There were no important differences in renal (509.7 (427.2-592.1) vs. 442.1 (361.2-523.0) arbitrary units, p = .286) and hepatic (604.7 (507.7-701.8) vs. 548.7 (444.0-653.3) arbitrary units, p = .376) microcirculatory blood flow between groups. Pigs assigned to colloid - compared to crystalloid - therapy also had less small intestinal, but not renal and hepatic, histopathological damage. CONCLUSIONS: Goal-directed isooncotic hydroxyethyl-starch colloid - compared to balanced isotonic crystalloid - therapy improved small intestinal, but not renal and hepatic, microcirculatory blood flow in pigs with ischemia/reperfusion injury. Whether colloid therapy improves small intestinal microcirculatory blood flow in patients with ischemia/reperfusion needs to be investigated in clinical trials.

The effects of respiratory rate and tidal volume on pulse pressure variation in healthy lungs-a generalized additive model approach may help overcome limitations.

Pulse pressure variation (PPV) is a well-established method for predicting fluid responsiveness in mechanically ventilated patients. The predictive accuracy is, however, disputed for ventilation with low tidal volume (VT) or low heart-rate-to-respiratory-rate ratio (HR/RR). We investigated the effects of VT and RR on PPV and on PPV's ability to predict fluid responsiveness. We included patients scheduled for open abdominal surgery. Prior to a 250 ml fluid bolus, we ventilated patients with combinations of VT from 4 to 10 ml kg-1 and RR from 10 to 31 min-1. For each of 10 RR-VT combinations, PPV was derived using both a classic approach and a generalized additive model (GAM) approach. The stroke volume (SV) response to fluid was evaluated using uncalibrated pulse contour analysis. An SV increase > 10% defined fluid responsiveness. Fifty of 52 included patients received a fluid bolus. Ten were fluid responders. For all ventilator settings, fluid responsiveness prediction with PPV was inconclusive with point estimates for the area under the receiver operating characteristics curve between 0.62 and 0.82. Both PPV measures were nearly proportional to VT. Higher RR was associated with lower PPV. Classically derived PPV was affected more by RR than GAM-derived PPV. Correcting PPV for VT could improve PPV's predictive utility. Low HR/RR has limited effect on GAM-derived PPV, indicating that the low HR/RR limitation is related to how PPV is calculated. We did not demonstrate any benefit of GAM-derived PPV in predicting fluid responsiveness.Trial registration: ClinicalTrials.gov, reg. March 6, 2020, NCT04298931.

Effect of carotid corrected flow time combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients: a prospective cohort study.

BACKGROUND: Hypotension often occurs following the induction of general anesthesia in elderly patients undergoing surgery and can lead to severe complications. This study assessed the effect of carotid corrected flow time (FTc) combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients. MATERIALS AND METHODS: The prospective cohort study was divided into two parts. The first part (Part I) consisted of 112 elderly patients. Carotid FTc was measured using Color Doppler Ultrasound 5 min before anesthesia induction. Hypotension was defined as a decrease of greater than 30% in systolic blood pressure (SBP) or a decrease of greater than 20% in mean arterial pressure (MAP) from baseline, or an absolute SBP below 90 mmHg and MAP below 60 mmHg within 3 min after induction of general anesthesia. The predictive value of carotid FTc was determined using receiver operating characteristic (ROC) curve. The second part (Part II) consisted of 65 elderly patients. Based on the results in Part I, elderly patients with carotid FTc below the optimal cut-off value received perioperative fluid therapy at a volume of 8 ml/kg of balanced crystalloids (lactated Ringer's solution) in 30 min before induction. The effect of carotid FTc combined with perioperative fluid therapy was assessed by comparing observed incidence of hypotension after induction. RESULTS: The area under the ROC for carotid FTc to predict hypotension after induction was 0.876 [95% confidence interval (CI) 0.800-0.952, P <0.001]. The optimal cut-off value was 334.95 ms (sensitivity of 87.20%; specificity of 82.20%). The logistic regression analysis revealed that carotid FTc is an independent predictor for post-induction hypotension in elderly patients. The incidence of post-induction hypotension was significantly lower ( P <0.001) in patients with carotid FTc less than 334.95 ms who received perioperative fluid therapy (35.71%) compared to those who did not (92.31%). CONCLUSIONS: Carotid FTc combined with the perioperative fluid therapy could significantly reduce the incidence of hypotension after the induction of general anesthesia in elderly patients.

Mean systemic filling pressure and venous return to assess the effects of passive leg raising and volume expansion in acute circulatory failure patients: a posthoc analysis of a multi-centre prospective study.

BACKGROUND: The main aim of the study was to investigate the behaviours of the mean systemic filling pressure (Pmsf), calculated by the mathematical method, and its derived variables of venous return after volume expansion (VE) and passive leg raising (PLR), with analysis according to fluid and PLR responsiveness. METHODS: This was a post-hoc analysis of a multicentre prospective study. We included 202 mechanically ventilated patients with acute circulatory failure. Pmsf, dVR (difference between Pmsf and central venous pressure [CVP]), and resistance to venous return (RVR) were calculated before/after PLR and before/after VE. Fluid- and PLR-responsiveness were defined according to the increase in cardiac index (CI) >15% after VE and >10% after PLR, respectively. RESULTS: Pmsf increased significantly after VE and PLR in both fluid and PLR-responder and non-responder groups. In fluid-responder patients, the increase in dVR was significantly higher than in non-responder group (1.5 [IQR:1.0-2.0] vs. 0.3 [IQR:-0.1-0.6] mmHg, p < 0.001) because of the larger increase in CVP relative to Pmsf in the non-responder group. The same findings were observed after PLR. RVR significantly decreased only in the fluid-responder and PLR-responder groups after VE and PLR. CONCLUSIONS: Venous return, derived from the mathematical model, increased in preload-dependent patients after VE and PLR because of the larger increases in Pmsf relative to CVP and the decreases in RVR. In preload-independent patients, VR did not change because of the larger rise in CVP compared to Pmsf after VE and PLR. These findings agree with the physiological model of circulation described by Guyton.

What every intensivist should know about the IVC.

Assessment of the IVC by point-of-care ultrasound in the context of resuscitation has been a controversial topic in the last decades. Most of the focus had been on its use as a surrogate marker for fluid responsiveness, with results being equivocal. We review its important anatomical aspects as well as the physiological rationale behind ultrasound assessment and propose a new way to do so, as well as explain its central role in the concept of fluid tolerance.