Pulse pressure variation guided goal-direct fluid therapy decreases postoperative complications in elderly patients undergoing laparoscopic radical resection of colorectal cancer: a randomized controlled trial.

OBJECTIVE: The use of goal-directed fluid therapy (GDFT) has been shown to reduce complications and improve prognosis in high-risk abdominal surgery patients. However, the utilization of pulse pressure variation (PPV) guided GDFT in laparoscopic surgery remains a subject of debate. We hypothesized that utilizing PPV guidance for GDFT would optimize short-term prognosis in elderly patients undergoing laparoscopic radical resection for colorectal cancer compared to conventional fluid therapy. METHODS: Elderly patients undergoing laparoscopic radical resection of colorectal cancer were randomized to receive either PPV guided GDFT or conventional fluid therapy and explore whether PPV guided GDFT can optimize the short-term prognosis of elderly patients undergoing laparoscopic radical resection of colorectal cancer compared with conventional fluid therapy. RESULTS: The incidence of complications was significantly lower in the PPV group compared to the control group (32.8% vs. 57.1%, P = .009). Additionally, the PPV group had a lower occurrence of gastrointestinal dysfunction (19.0% vs. 39.3%, P = .017) and postoperative pneumonia (8.6% vs. 23.2%, P = .033) than the control group. CONCLUSION: Utilizing PPV as a monitoring index for GDFT can improve short-term prognosis in elderly patients undergoing laparoscopic radical resection of colorectal cancer. REGISTRATION NUMBER: ChiCTR2300067361; date of registration: January 5, 2023.

Comparison of anaesthesia strategies on postoperative nausea and vomiting in laparoscopic sleeve gastrectomy: a randomised controlled trial.

BACKGROUND: Intra-operative anaesthesia management should be optimised to reduce the occurrence of postoperative nausea and vomiting in high-risk patients; however, a single intervention may not effectively reduce postoperative nausea and vomiting in such patients. This study assessed the effect of an optimised anaesthetic protocol versus a conventional one on postoperative nausea and vomiting in patients who underwent laparoscopic sleeve gastrectomy. METHODS: A single-centre randomised trial was conducted at Peking University Shenzhen Hospital from June 2021 to December 2022. Among 168 patients who underwent laparoscopic sleeve gastrectomy, 116 qualified, and 103 completed the study with available data. Patients were categorized into the conventional group (received sevoflurane and standard fluids) and the optimised group (underwent propofol-based anaesthesia and was administered goal-directed fluids). The primary endpoints were postoperative nausea and vomiting incidence and severity within 24 h. RESULTS: Postoperative nausea and vomiting assessment at 0-3 h post-surgery revealed no significant differences between groups. However, at 3-24 h, the optimised anaesthetic protocol group showed lower postoperative nausea and vomiting incidence and severity than those of the conventional group (P = 0.005). In the conventional group, 20 (37.04%) patients experienced moderate-to-severe postoperative nausea and vomiting, compared to six (12.25%) patients in the optimised group (odds ratio = 0.237; 95% CI = 0.086, 0.656; P = 0.006). No significant differences were noted in antiemetic treatment, moderate-to-severe pain incidence, anaesthesia recovery, post-anaesthetic care unit stay, or postoperative duration between the groups. While the total intra-operative infusion volumes were comparable, the optimised group had a significantly higher colloidal infusion volume (500 mL vs. 0 mL, P = 0.014) than that of the conventional group. CONCLUSIONS: The incidence and severity of postoperative nausea and vomiting 3-24 h postoperatively in patients who underwent laparoscopic sleeve gastrectomy were significantly lower with propofol-based total intravenous anaesthesia and goal-directed fluid therapy than with sevoflurane anaesthesia and traditional fluid management. Total intravenous anaesthesia is an effective multimodal antiemetic strategy for bariatric surgery. TRIAL REGISTRATION: This trial was registered with the Chinese Clinical Trial Registry (ChiCTR-TRC- 2,100,046,534, registration date: 21 May 2021).

Goal-directed fluid therapy during post-resection phase in low central venous pressure assisted laparoscopic hepatectomy: a randomized controlled superiority trial.

PURPOSE: The purpose of this prospective single blinded randomized controlled trial was to find out whether goal-directed fluid therapy (GDFT) strategy in post-transection period in low central venous pressure (CVP) assisted laparoscopic hepatectomy (LH) has more benefit than traditional fluid strategy. METHODS: Between April 2020 and Dec 2021, patients who were scheduled for laparoscopic liver resection surgery were eligible to participate in the study. Patients were randomly divided into two groups: control group that received traditional fluid strategy in post-transection period in low CVP assisted laparoscopic hepatectomy and GDFT strategy group that received GDFT strategy in post-transection period. The primary outcome parameter is the incidence of postoperative complications. Secondary outcome parameters include perioperative clinical outcomes, postoperative clinical outcomes, length of hospital stay after surgery, postoperative lactic acid, fluids and vasoactive medications during the operation. RESULTS: A total of 159 patients in the control group and 160 patients in the GDFT were included. Two groups had no significant difference in the incidence of postoperative complications including pneumonia (P = 0.34), acute kidney injury (P = 0.72), hepatic insufficiency (P = 0.25), pleural effusion (P = 0.08) and seroperitoneum (P = 1.00), respectively. The amount of perioperative urine output is fewer in GDFT group than in the control group (P = 0.0354), while other perioperative variables and postoperative variables were comparable between two groups. CONCLUSIONS: The results show the implementation of GDFT strategy is not associated with fewer postoperative complications. GDFT strategy did not result in improved outcomes in low CVP-assisted laparoscopic hepatectomy.

Clinical outcomes of a prospective randomized comparison of bioreactance monitoring versus pulse-contour analysis in a stroke-volume based goal-directed fluid resuscitation protocol in brain-dead organ donors.

Eighty percent of brain-dead (BD) organ donors develop hypotension and are frequently hypovolemic. Fluid resuscitation in a BD donor is controversial. We have previously published our 4-h goal-directed stroke volume (SV)-based fluid resuscitation protocol which significantly decreased time on vasopressors and increased transplanting four or more organs. The SV was measured by pulse-contour analysis (PCA) or an esophageal doppler monitor, both of which are invasive. Thoracic bioreactance (BR) is a non-invasive portable technology that measures SV but has not been studied in BD donors. We performed a randomized prospective comparative study of BR versus PCA technology in our fluid resuscitation protocol in BD donors. Eighty-four donors (53.1%) were randomized to BR and 74 donors to PCA (46.8%). The two groups were well matched based on 24 demographic, social, and initial laboratory factors, without any significant differences between them. There was no difference in the intravenous fluid infused over the 4-h study period [BR 2271 ± 823 vs. PCA 2230 ± 962 mL; p = .77]. There was no difference in the time to wean off vasopressors [BR 108.8 ± 61.8 vs. PCA 150.0 ± 68 min p = .07], nor in the number of donors off vasopressors at the end of the protocol [BR 16 (28.6%) vs. PCA 15 (29.4%); p = .92]. There was no difference in the total number of organs transplanted per donor [BR 3.25 ± 1.77 vs. PCA 3.22 ± 1.75; p = .90], nor in any individual organ transplanted. BR was equivalent to PCA in clinical outcomes and provides a simple, non-invasive, portable technology to monitor fluid resuscitation in organ donors.

Goal-Directed Fluid Therapy and major postoperative complications in elective craniotomy. A retrospective analysis of a before-after multicentric study.

BACKGROUND: Goal-Directed Fluid Therapy (GDFT) is recommended to decrease major postoperative complications. However, data are lacking in intra-cranial neurosurgery. METHODS: We evaluated the efficacy of a GDFT protocol in a before/after multi-centre study in patients undergoing elective intra-cranial surgery for brain tumour. Data were collected during 6 months in each period (before/after). GDFT was performed in high-risk patients: ASA score III/IV and/or preoperative Glasgow Coma Score (GCS) < 15 and/or history of brain tumour surgery and/or tumour greater size ≥ 35 mm and/or mid-line shift ≥ 3 mm and/or significant haemorrhagic risk. Major postoperative complication was a composite endpoint: re-intubation after surgery, a new onset of GCS < 15 after surgery, focal motor deficit, agitation, seizures, intra-cranial haemorrhage, stroke, intra-cranial hypertension, hospital-acquired related pneumonia, surgical site infection, cardiac arrythmia, invasive mechanical ventilation ≥ 48 h and in-hospital mortality. RESULTS: From July 2018 to January 2021, 344 patients were included in 3 centers: 171 in the before and 173 in the after (GDFT) period. Thirty-six (21.1%) patients displayed a major postoperative complication in the Before period, and 50 (28.9%) in the After period (p = 0.1). In the propensity score analysis, we matched 48 patients in each period: 9 (18.8%) patients in the After period and 14 (29.2%) patients in the Before period displayed a major perioperative complication (p = 0.2). Sixty-two (35.8%) patients received GDFT in the After period, with great heterogeneity among centers (p < 0.05). CONCLUSIONS: In our before-after study, GDFT was not associated with a decrease in postoperative major complications in elective intra-cranial neurosurgery.

Effect of perioperative goal-directed fluid therapy on postoperative complications after thoracic surgery with one-lung ventilation: a systematic review and meta-analysis.

BACKGROUND: An understanding of the impact of goal-directed fluid therapy (GDFT) on the outcomes of patients undergoing one-lung ventilation (OLV) for thoracic surgery remains incomplete and controversial. This meta-analysis aimed to assess the effect of GDFT compared to other fluid therapy strategies on the incidence of postoperative complications in patients with OLV. METHODS: The Embase, Cochrane Library, Web of Science, and MEDLINE via PubMed databases were searched from their inception to November 30, 2022. Forest plots were constructed to present the results of the meta-analysis. The quality of the included studies was evaluated using the Cochrane Collaboration tool and Risk Of Bias In Non-Randomized Study of Interventions (ROBINS-I). The primary outcome was the incidence of postoperative complications. Secondary outcomes were the length of hospital stay, PaO2/FiO2 ratio, total fluid infusion, inflammatory factors (TNF-α, IL-6), and postoperative bowel function recovery time. RESULTS: A total of 1318 patients from 11 studies were included in this review. The GDFT group had a lower incidence of postoperative complications [odds ratio (OR), 0.47; 95% confidence interval (95% CI), 0.29-0.75; P = 0.002; I 2, 67%], postoperative pulmonary complications (OR 0.48, 95% CI 0.27-0.83; P = 0.009), and postoperative anastomotic leakage (OR 0.51, 95% CI 0.27-0.97; P = 0.04). The GDFT strategy reduces total fluid infusion. CONCLUSIONS: GDFT is associated with lower postoperative complications and better survival outcomes after thoracic surgery for OLV.

Comparison of two techniques of goal directed fluid therapy in elective neurosurgical patients - a randomized controlled study.

BACKGROUND: Goal directed fluid therapy (GDFT) may be a rational approach to adopt in neurosurgical patients, in whom intravascular volume optimization is of utmost importance. Most of the parameters used to guide GDFT are derived invasively. We postulated that the total volume of intraoperative intravenous fluid administered during elective craniotomy for supratentorial brain tumours would be comparable between two groups receiving GDFT guided either by the non-invasively derived plethysmography variability index (PVI) or by stroke volume variation (SVV). METHODS: 60 ASA category 1, 2 and 3 patients between 18 and 70 years of age were randomized to receive intraoperative fluid guided either by SVV (SVV group; n = 31) or PVI (PVI group; n = 29). The total volume of fluid administered intraoperatively was recorded. Serum creatinine was measured before the surgery, at the end of the surgery, 24 h after surgery and on the fifth post-operative day. Arterial cannulation was performed before induction in all patients. Serum lactate was measured before induction, once in 2 h intraoperatively, at the end of the surgery and 24 h after the surgery. Brain relaxation score was assessed by the surgeon during dural opening and dural closure. Patients were followed up till discharge or death. The duration of mechanical ventilation and the duration of hospital stay was noted for all patients. RESULTS: The volume of fluid given intraoperatively was significantly higher in the SVV group (p = 0.005). The two groups were comparable with respect to serum lactate and serum creatinine measured at pre-determined time intervals. Brain relaxation score was also comparable between the groups. SVV and PVI displayed moderate to strong correlation intraoperatively. The duration of mechanical ventilation and the length of the hospital stay were comparable between the two groups. CONCLUSIONS: PVI and SVV are equally effective in guiding GDFT in adults undergoing elective craniotomy for supratentorial brain tumours.

Intraoperative Blood Pressure Lability Acts as a Key Mediator in the Impacts of Goal-Directed Fluid Therapy on Postoperative Complications in Patients Undergoing Major Spine Surgery.

Objective Although goal-directed fluid therapy (GDFT) has been proven to be effective in reducing the incidence of postoperative complications, the underlying mechanisms remain unknown. The aim of this study was to examine the mediating role of intraoperative hemodynamic lability in the association between GDFT and the incidence of postoperative complications. We further tested the role of this mediation effect using mean arterial pressure, a hemodynamic indicator. Methods This secondary analysis used the dataset of a completed nonrandomized controlled study to investigate the effect of GDFT on the incidence of postoperative complications in patients undergoing posterior spine arthrodesis. We used a simple mediation model to test whether there was a mediation effect of average real variability between the association of GDFT and postoperative complications. We conducted mediation analysis using the mediation package in R (version 3.1.2), based on 5,000 bootstrapped samples, adjusting for covariates. Results Among the 300 patients in the study, 40% (120/300) developed postoperative complications within 30 days. GDFT was associated with fewer 30-day postoperative complications after adjustment for confounders (odds ratio: 0.460, 95% CI: 0.278, 0.761; P = 0.003). The total effect of GDFT on postoperative complications was -0.18 (95% CI: -0.28, -0.07; P < 0.01). The average causal mediation effect was -0.08 (95% CI: -0.15, -0.04; P < 0.01). The average direct effect was -0.09 (95% CI: -0.20, 0.03; P = 0.17). The proportion mediated was 49.9% (95% CI: 18.3%, 140.0%). Conclusions The intraoperative blood pressure lability mediates the relationship between GDFT and the incidence of postoperative complications. Future research is needed to clarify whether actively reducing intraoperative blood pressure lability can prevent postoperative complications.

Current Commonly Used Dynamic Parameters and Monitoring Systems for Perioperative Goal-Directed Fluid Therapy: A Review.

Goal-directed fluid therapy (GDFT) is usually recommended in patients undergoing major surgery and is essential in enhanced recovery after surgery (ERAS) protocols. This fluid regimen is usually guided by dynamic hemodynamic parameters and aims to optimize patients' cardiac output to maximize oxygen delivery to their vital organs. While many studies have shown that GDFT benefits patients perioperatively and can decrease postoperative complications, there is no consensus on which dynamic hemodynamic parameters to guide GDFT with. Furthermore, there are many commercialized hemodynamic monitoring systems to measure these dynamic hemodynamic parameters, and each has its pros and cons. This review will discuss and review the commonly used GDFT dynamic hemodynamic parameters and hemodynamic monitoring systems.

Impact of Goal-Directed Fluid Therapy on Postoperative Outcomes in Colorectal Surgery: An Evidence-Based Review.

PURPOSE: To investigate the effects of goal-directed fluid therapy (GDFT) or conventional fluid therapy (CFT) in improving postoperative outcomes in patients undergoing colorectal surgeries. DESIGN: Evidence-Based Review. METHODS: Following the guidelines outlined in the PRISMA statement, a comprehensive search was conducted using PubMed, Elsevier ScienceDirect, Oxford Academic, EBSCO, Google Scholar, Cochrane Library, and gray literature. Only randomized controlled studies and preappraised evidence such as systematic review with meta-analysis examining the effects of GDFT and CFT in colorectal surgery were included. The quality appraisal of the literature was conducted using the proposed algorithm described in the Johns Hopkins Nursing Evidence-Based Practice Evidence Level and Quality Guide. FINDINGS: Two systematic reviews with meta-analyses and four randomized controlled trials (RCT) involving 2018 patients were included in this review. Overall, the use of GDFT did not shorten the hospital length of stay (LOS), reduce 30-day mortality, lower overall morbidity rates, or decrease incidence of postoperative ileus. Additionally, the return of bowel function was not improved using GDFT or CFT. However, when GDFT was implemented within enhanced recovery after surgery (ERAS) programs, there was a significant reduction in hospital LOS. . When GDFT was used in a non-ERAS patient care setting, there was a significant reduction in overall morbidity rate and faster time to first flatus. All studies included in the review were categorized as Level I and rated Grade A, implying strong confidence in the true effects of GDFT on all outcome measures in the review. CONCLUSIONS: The benefits of GDFT in colorectal surgery are still unclear. Considerable heterogeneity based on the types of GDFT devices, patient outcome parameters, and fluid protocols limit the application to clinical practice. Furthermore, there was limited data on the effects of GDFT in high-risk patients for colorectal surgery.

Do pulmonary artery catheters have a role in the 21st century intensive care unit?

Use of pulmonary artery catheters on general intensive care units has declined. Reasons for this decline are explored and the evidence for and against their use is re-examined. We conclude that the growing consensus for a lack of benefit is not justified, and use of pulmonary artery catheters can still be appropriate.

Ultrasound Hepatic Vein Ratios Are Associated With the Development of Acute Kidney Injury After Cardiac Surgery.

OBJECTIVE: The authors investigated the use of hepatic venous and right-heart ultrasound parameters in predicting cardiac surgery-associated acute kidney injury (AKI). DESIGN: This was a prospective, contextual, descriptive two-center study. Blood tests,clinical and ultrasound data were obtained preoperatively, and postoperative day one, and day four. The hepatic vein, inferior vena cava, and right-heart Doppler ultrasound parameters were obtained and analyzed. SETTING: The sites of the study were Johannesburg, South Africa, and Aarhus, Denmark. PARTICIPANTS: Adult patients who satisfied inclusion criteria, between August 2019 and January 2020, were included, with a total of 152 participants. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The median (interquartile range) age of patients was 68 (55-73) years, predominantly male, and the majority were hypertensive. Of 152 patients analyzed, 54 (35%) patients developed AKI. Among these, 37 (69%) were classified as Kidney Disease: Improving Global Outcomes (KDIGO) stage I, 11 (20%) as stage II, while six (11%) were stage III. Age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.00-1.10 p = 0.031), The European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (AOR 1.43, 95% CI 1.14-1.80, p = 0.005], and preoperative serum creatinine (AOR 1.04, 95% CI 1.01-1.08, p = 0.013) were predictive of AKI. Those who developed AKI had experienced longer cardiopulmonary bypass (CPB) times (p < 0.001). Preoperatively, hepatic vein S-wave measurements were significantly higher in patients with AKI (p < 0.05). On postoperative day one (D1), the hepatic vein flow ratios of patients with AKI were significantly decreased, driven by low S waves and high D waves, and accompanied by significantly elevated central venous pressure (CVP) levels. CVP levels on D1 postoperatively were predictive of AKI (AOR 1.31, 95% CI 1.11-1.55, p = 0.001). Measurements of right ventricular (RV) base, tricuspid annular plane excursion (TAPSE), and inferior vena cava were not associated with the development of AKI (p > 0.05). CONCLUSION: There was an association between the development of AKI and a decrease in hepatic flow ratios on D1, driven by low S-wave and high D-wave velocities. The presence of venous congestion was reflected by significantly elevated CVP values, which were independently associated with AKI on D1. RV base and TAPSE measurements were, however, not associated with AKI. These parameters may reflect perioperative circumstances, including prolonged CPB times and potential fluid management, which can be modified in this period.

The Impact of Individualized Hemodynamic Management on Intraoperative Fluid Balance and Hemodynamic Interventions during Spine Surgery in the Prone Position: A Prospective Randomized Trial.

Background and Objectives: The effect of individualized hemodynamic management on the intraoperative use of fluids and other hemodynamic interventions in patients undergoing spinal surgery in the prone position is controversial. This study aimed to evaluate how the use of individualized hemodynamic management based on extended continuous non-invasive hemodynamic monitoring modifies intraoperative hemodynamic interventions compared to conventional hemodynamic monitoring with intermittent non-invasive blood pressure measurements. Methods: Fifty adult patients (American Society of Anesthesiologists physical status I−III) who underwent spinal procedures in the prone position and were then managed with a restrictive fluid strategy were prospectively randomized into intervention and control groups. In the intervention group, individualized hemodynamic management followed a goal-directed protocol based on continuously non-invasively measured blood pressure, heart rate, cardiac output, systemic vascular resistance, and stroke volume variation. In the control group, patients were monitored using intermittent non-invasive blood pressure monitoring, and the choice of hemodynamic intervention was left to the discretion of the attending anesthesiologist. Results: In the intervention group, more hypotensive episodes (3 (2−4) vs. 1 (0−2), p = 0.0001), higher intraoperative dose of ephedrine (0 (0−10) vs. 0 (0−0) mg, p = 0.0008), and more positive fluid balance (680 (510−937) vs. 270 (196−377) ml, p < 0.0001) were recorded. Intraoperative norepinephrine dose and postoperative outcomes did not differ between the groups. Conclusions: Individualized hemodynamic management based on data from extended non-invasive hemodynamic monitoring significantly modified intraoperative hemodynamic management and was associated with a higher number of hemodynamic interventions and a more positive fluid balance.

Effect of different levels of stroke volume variation on the endothelial glycocalyx of patients undergoing colorectal surgery: A randomized clinical trial.

NEW FINDINGS: What is the central question of this study? Massive infusion can destroy the endothelial glycocalyx. We compared the serum concentrations of endothelial glycocalyx components and atrial natriuretic peptide and the outcomes of patients with different levels of stroke volume variation (SVV). What is the main finding and its importance? With a decrease in SVV, the serum concentrations of endothelial glycocalyx components and atrial natriuretic peptide increased, whereas the oxygenation index decreased. When the intraoperative SVV was maintained at 7-10%, the patients had better postoperative recovery and shorter postoperative hospital stays. Therefore, it is advisable to maintain the SVV between 7 and 10%. ABSTRACT: Dynamic haemodynamic parameters, such as stroke volume variation (SVV), can be used for blood volume monitoring. However, studies have determined the SVV threshold but not the optimal level. The endothelial glycocalyx (EG) plays an important role in maintaining vascular permeability. Moreover, rapid and massive infusion can lead to the degradation, shedding and destruction of the EG. We aimed to explore the effects of different SVV values (11-14, 7-10 or 3-6%) on the EG in 54 patients who were scheduled for elective colorectal tumour surgery and to identify the optimal peri-operative fluid therapy strategy. The concentrations of EG degradation products (heparin sulphate, hyaluronic acid and syndecan-1) and atrial natriuretic peptide were higher when the SVV was maintained between 3 and 6% after fluid therapy compared with pre-infusion (P < 0.05). Comparison of postoperative complications and hospitalization time among the three SVV levels was not statistically significant (P > 0.05). The postoperative hospitalization time in patients with SVV of 7-10% was shorter than that in patients with SVV of 3-6%. Infusion of a large volume of fluid, with increasing EG degeneration and atrial natriuretic peptide concentrations, might be related to postoperative outcomes.

Goal-directed fluid therapy in emergency abdominal surgery: a randomised multicentre trial.

BACKGROUND: More than 50% of patients have a major complication after emergency gastrointestinal surgery. Intravenous (i.v.) fluid therapy is a life-saving part of treatment, but evidence to guide what i.v. fluid strategy results in the best outcome is lacking. We hypothesised that goal-directed fluid therapy during surgery (GDT group) reduces the risk of major complications or death in patients undergoing major emergency gastrointestinal surgery compared with standard i.v. fluid therapy (STD group). METHODS: In a randomised, assessor-blinded, two-arm, multicentre trial, we included 312 adult patients with gastrointestinal obstruction or perforation. Patients in the GDT group received i.v. fluid to near-maximal stroke volume. Patients in the STD group received i.v. fluid following best clinical practice. Postoperative target was 0-2 L fluid balance. The primary outcome was a composite of major complications or death within 90 days. Secondary outcomes were time in intensive care, time on ventilator, time in dialysis, hospital stay, and minor complications. RESULTS: In a modified intention-to-treat analysis, we found no difference in the primary outcome between groups: 45 (30%) (GDT group) vs 39 (25%) (STD group) (odds ratio=1.24; 95% confidence interval, 0.75-2.05; P=0.40). Hospital stay was longer in the GDT group: median (inter-quartile range), 7 (4-12) vs 6 days (4-8.5) (P=0.04); no other differences were found. CONCLUSION: Compared with pressure-guided i.v. fluid therapy (STD group), flow-guided fluid therapy to near-maximal stroke volume (GDT group) did not improve the outcome after surgery for bowel obstruction or gastrointestinal perforation but may have prolonged hospital stay. CLINICAL TRIAL REGISTRATION: EudraCT number 2015-000563-14; the Danish Scientific Ethics Committee and the Danish Data Protection Agency (REG-18-2015).

Effect of fluid strategy on stroke volume, cardiac output, and fluid responsiveness in adult patients undergoing major abdominal surgery: a sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial.

BACKGROUND: We designed a prospective sub-study of the larger Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial to measure differences in stroke volume and other haemodynamic parameters at the end of the intraoperative fluid protocols. The haemodynamic effects of the two fluid regimens may increase our understanding of the observed perioperative outcomes. METHODS: Stroke volume and cardiac output were measured with both an oesophageal Doppler ultrasound monitor and arterial pressure waveform analysis. Stroke volume variation, pulse pressure variation, and plethysmographic variability index were also obtained. A passive leg raise manoeuvre was performed to identify fluid responsiveness. RESULTS: Analysis of 105 patients showed that the primary outcome, Doppler monitor-derived stroke volume index, was higher in the liberal group: restrictive 38.5 (28.6-48.8) vs liberal 44.0 (34.9-61.9) ml m-2; P=0.043. Similarly, there was a higher cardiac index in the liberal group: 2.96 (2.32-4.05) vs 2.42 (1.94-3.26) L min-1 m-2; P=0.015. Arterial-pressure-based stroke volume and cardiac index did not differ, nor was there a significant difference in stroke volume variation, pulse pressure variation, or plethysmographic variability index. The passive leg raise manoeuvre showed fluid responsiveness in 40% of restrictive and 30% of liberal protocol patients (not significant). CONCLUSIONS: The liberal fluid group from the RELIEF trial had significantly higher Doppler ultrasound monitor-derived stroke volume and cardiac output compared with the restrictive fluid group at the end of the intraoperative period. Measures of fluid responsiveness did not differ significantly between groups. CLINICAL TRIAL REGISTRATION: ACTRN12615000125527.

Preoperative carbohydrate loading and intraoperative goal-directed fluid therapy for elderly patients undergoing open gastrointestinal surgery: a prospective randomized controlled trial.

BACKGROUND: The effect of a combination of a goal-directed fluid protocol and preoperative carbohydrate loading on postoperative complications in elderly patients still remains unknown. Therefore, we designed this trial to evaluate the relative impact of preoperative carbohydrate loading and intraoperative goal-directed fluid therapy versus conventional fluid therapy (CFT) on clinical outcomes in elderly patients following gastrointestinal surgery. METHODS: This prospective randomized controlled trial with 120 patients over 65 years undergoing gastrointestinal surgery were randomized into a CFT group (n = 60) with traditional methods of fasting and water-deprivation, and a GDFT group (n = 60) with carbohydrate (200 ml) loading 2 h before surgery. The CFT group underwent routine monitoring during surgery, however, the GDFT group was conducted by a Vigileo/FloTrac monitor with cardiac index (CI), stroke volume variation (SVV), and mean arterial pressure (MAP). For all patients, demographic data, intraoperative parameters and postoperative outcomes were recorded. RESULTS: Patients in the GDFT group received significantly less crystalloids fluid (1111 ± 442.9 ml vs 1411 ± 412.6 ml; p < 0.001) and produced significantly less urine output (200 ml [150-300] vs 400 ml [290-500]; p < 0.001) as compared to the CFT group. Moreover, GDFT was associated with a shorter average time to first flatus (56 ± 14.1 h vs 64 ± 22.3 h; p = 0.002) and oral intake (72 ± 16.9 h vs 85 ± 26.8 h; p = 0.011), as well as a reduction in the rate of postoperative complications (15 (25.0%) vs 29 (48.3%) patients; p = 0.013). However, postoperative hospitalization or hospitalization expenses were similar between groups (p > 0.05). CONCLUSIONS: Focused on elderly patients undergoing open gastrointestinal surgery, we found perioperative fluid optimisation may be associated with improvement of bowel function and a lower incidence of postoperative complications. TRIAL REGISTRATION: ChiCTR, ChiCTR1800018227 . Registered 6 September 2018 - Retrospectively registered.

Comparison between pulse pressure variation and systolic pressure variation measured from a peripheral artery for accurately predicting fluid responsiveness in mechanically ventilated dogs.

OBJECTIVE: To compare pulse pressure variation (PPV) and systolic pressure variation (SPV) measured from a peripheral artery to predict fluid responsiveness in anesthetized healthy dogs. STUDY DESIGN: Prospective study. ANIMALS: A total of 39 dogs (13.8-26.8 kg) anesthetized with isoflurane for elective ovariohysterectomy. METHODS: Ventilation was controlled (tidal volume 12 mL kg-1; 40% inspiratory pause). PPV and SPV were recorded from a dorsal pedal artery catheter using an automated algorithm. A fluid challenge (FC) with lactated Ringer's solution (20 mL kg-1 over 15 minutes) was administered once (21 animals) or twice (18 animals) before surgery. Increases in transpulmonary thermodilution stroke volume index > 15% from values recorded before each FC defined responders to volume expansion. Final fluid responsiveness status was based on the response to single FC or second FC. Predictive ability of PPV and SPV was compared by receiver operating characteristic (ROC) curve analysis and by the range of cut-off values associated with uncertain results (gray zone). RESULTS: All animals after the single FC were responders; all animals administered two FCs were nonresponders after the second FC. The area under the ROC curve (AUROC) of PPV (0.968) did not differ from that of SPV (0.937) (p = 0.45). Best cut-off thresholds to discriminate responders from nonresponders were >11.7% (PPV) and >7.4 mmHg (SPV). The gray zone of PPV and SPV was 8.2-14.6% and 7.0-7.4 mmHg, respectively. The percentage of animals with PPV and SPV values within the gray zone was less for SPV (10.2%) than for PPV (30.8%). CONCLUSIONS AND CLINICAL RELEVANCE: PPV and SPV obtained from the dorsal pedal artery are useful predictors of fluid responsiveness in dogs. Using an automated algorithm, SPV may more accurately predict fluid responsiveness than PPV, with responders identifiable by PPV > 14.6% and SPV > 7.4 mmHg.

Use of aortic flow indexes derived from transthoracic echocardiography to evaluate response to a fluid challenge in anesthetized dogs.

OBJECTIVE: To evaluate the ability of transthoracic echocardiographic aortic flow measurements to discriminate response to a fluid challenge (FC) in healthy anesthetized dogs. STUDY DESIGN: Prospective experimental study. ANIMALS: A total of 48 isoflurane-anesthetized dogs (14.2-35.0 kg) undergoing elective surgery. METHODS: Fluid responsiveness was evaluated before surgery by FC (lactated Ringer's 10 mL kg-1 intravenously over 5 minutes). Percentage increases in transpulmonary thermodilution stroke volume (ΔSVTPTD) >15% from values recorded before FC defined responders to volume expansion. A group of 24 animals were assigned as nonresponders (ΔSVTPTD ≤15%). When ΔSVTPTD was >15% after the first FC, additional FC were administered until ΔSVTPTD was ≤15%. Final fluid responsiveness status was based on the response to the last FC. Percentage increases after FC in aortic flow indexes [velocity time integral (ΔVTIFC) and maximum acceleration (ΔVmaxFC)] and in mean arterial pressure (ΔMAPFC) were compared with ΔSVTPTD. RESULTS: After one FC, 24 animals were responders. For nonresponders, ΔSVTPTD was ≤15% after one, two and three FCs in eight/24, 15/24 and one/24 animals, respectively. The FC that defined responsiveness increased ΔSVTPTD by 29 (18-53)% in responders and by 8 (-3 to 15)% in nonresponders [mean (range)]. The area under the receiver operating characteristics curve (AUROC) of ΔVTIFC (0.901) was larger than the AUROCs of ΔVmaxFC (0.774, p = 0.041) and ΔMAPFC (0.519, p < 0.0001). ΔMAPFC did not predict responsiveness (p = 0.826). Best cut-off thresholds for discriminating responders, with respective zones of diagnostic uncertainty (gray zones) were >14.7 (10.8-17.6)% for ΔVTIFC and >8.6 (-0.3 to 14.7)% for ΔVmaxFC. Animals within the gray zone were 17% (ΔVTIFC) and 50% (ΔVmaxFC). CONCLUSIONS AND CLINICAL RELEVANCE: Changes in VTI induced by FC can determine responsiveness with reasonable accuracy in dogs and could play an important role in goal-directed fluid therapy.

A stroke volume-based fluid resuscitation protocol decreases vasopressor support and may increase organ yield in brain-dead donors.

Brain-dead donors are frequently hypovolemic and hypotensive requiring vasopressor support. We studied a stroke volume-based fluid resuscitation and vasopressor weaning protocol prospectively on 64 hypotensive donors, with a recent control cohort of 30 hypotensive donors treated without a protocol. Stroke volume was measured every 30 minutes for 4 hours by pulse contour analysis or esophageal Doppler. A 500 mL saline fluid bolus was infused over 30 minutes and repeated if the stroke volume increased by 10%. No fluid was infused if the stroke volume did not increase by 10%. Vasopressors were weaned every 10 minutes if the mean arterial pressure was greater than 65 mm Hg. The protocol group received 1937 ± 906 mL fluid compared to 1323 ± 919 mL in the control group (P = .003). Mean time on vasopressors was decreased from 957.6 ± 586.2 to 176.3 ± 82.2 minutes (P<.001). Donors in the protocol group were more likely to donate four or more organs than donors in the control group (OR = 4.114, 95% Confidence Interval (CI) = 1.003-16.876). While more organs were transplanted per donor in the protocol group (3.39 ± 1.52) than in the control group (2.93 ± 1.44) (P = .268), the difference did not reach statistical significance. A goal-directed fluid resuscitation protocol decreased organ ischemia and may increase organs transplanted.