The correlation between Corrected Flow Time (FTc) Based on Esophageal Doppler Monitoring and Pleth Variability Index (PVI) in the Fluid Therapy in Patients undergoing Total Abdominal Hysterectomy

Background: The occurrence of bleeding during major surgeries is common and requires timely and accurate management in the prevention and treatment of hypovolemia and hemodynamic instability during and after surgery. This study evaluated the correlation and agreement between the two protocols determining the status of the hypovolemia during hysterectomy. Methods: This study was a randomized single-blinded clinical trial. The study population included 30 patients undergoing Total Abdominal Hysterectomy in Shariati Hospital in Tehran between 2015 and 2016. The patients were randomly assigned to two groups using a randomized table of numbers, so that in the FTc group, fluid therapy was performed based on the FTc index and in the PVI group based on the PVI index. The changes in FTc and PVI values were recorded every 5 minutes and the changes in the two indicators from the beginning to the end of the treatment were evaluated. At the beginning and end of the surgery, an arterial blood gas analysis (ABG) was also performed. The amount of bleeding during operation and urinary output were recorded in two groups. Results: There was no significant difference across the two groups in total fluid intake during surgery, mean volume of blood loss, mean urine output, and duration of surgery. The arterial blood gas status was also similar in both groups at the beginning and the end of the operation. We found a strong adverse correlation between FTC and PVI indices at the different time points evaluated within the surgery. In total, there was a strong correlation between the mean FTC and the mean PVI during the first hour (r=-0.765, P < 0.001) and the second hour (r=-0.941, -P < 0.001) of operation. Considering the cut-off point of 350msec for the FTC and 13% for the PVI in predicting hypovolemia, the agreement between the two protocols in fluid therapy during the first hour after surgery was 79.8% and 76.6%. Conclusion: There is a strong and significant correlation between the two FTC (with a cut off of 350) and PVI (with a cut point of 13%) to predict need for fluid therapy.

Effects of Fluid Therapy on Mesenteric Microcirculation Using New Probe-Based Confocal Laser Endomicroscopy (Cellvizio®) in a Porcine Model of Endotoxic Shock

<b><i>Background:</i></b> Microcirculatory alterations have been observed at the early phase of sepsis, although macrocirculation seems preserved. The aim of this study was to analyze the effect of crystalloid fluid therapy on mesenteric microcirculation, assessed by using the confocal laser endomicroscope Cellvizio®, in an endotoxic porcine model. <b><i>Methods:</i></b> It is a prospective endotoxic shock (lipopolysaccharide infusion) experimental trial. Piglets were divided into 3 groups: 6 in the sham group (no LPS injection, no fluid), 9 in the control group (LPS infusion, no fluid), and 6 in the crystalloids group (LPS infusion and fluid resuscitation with crystalloids). Fluid resuscitation consisted in a fluid bolus of 20 mL/kg 0.9% saline over 30 min followed by a 10 mL/kg/h fluid rate over 4 h. Mesenteric microcirculation was assessed using a confocal laser endomicroscope (Cellvizio®). Blood flow within capillaries was visually assessed according to the point of care microcirculation (POEM) score. <b><i>Results:</i></b> At baseline, the 3 groups were similar regarding hemodynamic, biological, and microcirculatory parameters. At T360, the POEM score significantly decreased in the control and crystalloids groups, whereas it remained unchanged in the sham group (respectively, 1.62 ± 1.06, 1.2 ± 0.45, and 5.0 ± 0, <i>p</i> = 0.011). There was no significant difference in cardiac output at T360 between the sham and crystalloids groups (3.1 ± 0.8 vs. 2.3 ± 0.6, <i>p</i> = 0.132) or between the control and crystalloids groups (2.0 ± 0.6 vs. 2.3 ± 0.6, <i>p</i> = 0.90). <b><i>Conclusion:</i></b> There was no significant improvement of microcirculatory alterations after crystalloids resuscitation despite improvement in macrocirculatory parameters in early experimental sepsis.

Norepinephrine in Goal-Directed Fluid Therapy during General Anesthesia in Elderly Patients Undergoing Spinal Operation: Determining Effective Infusion Rate to Enhance Postoperative Functions

Background and Objective: Intraoperative hypotension is a common complication in general anesthesia that could result in different serious complications particularly in elderly patients. This Randomized Clinical Trial (RCT) aims to determine effective continuous infusion rate of norepinephrine to prevent intraoperative hypotension during spinal surgery under general anesthesia in elderly patients. Methods: This RCT was conducted on elderly patients (n= 108) undergoing general anesthesia for posterior lumbar spinal fusion. The patients were randomly divided into 0.030, 0.060, and 0.090 μg.kg-1.min-1 groups of norepinephrine infusion rates. The outcomes were assessed at entrance to operation room (T0), 15 mins after anesthesia induction (T1), 60 mins following surgery (T2), and immediately after surgery (T3). The intraoperative and postoperative complications and rehabilitation outcomes were comparatively assessed. Results: All three groups significantly reduced the incidence of delayed wound healing (0.030 vs. 0.060 vs. 0.090 μg.kg-1.min-1; 33.3% vs. 10% vs. 10%, P=0.024) and wound infection (26.7% vs. 6.7% vs. 6.7%, P=0.031). Intraoperative total fluid volume and colloids volume in the 0.030 group were significantly higher than 0.060 and 0.090 groups (P=0.005, P=0.003, and P=0.01, respectively). The 0.060 and 0.090 groups significantly increased mean-arterial-pressure than the 0.030 group at T2 and T3. Both 0.060 and 0.090 infusion rates significantly reduced intraoperative hypotension than 0.030 dosage (P=0.01 and P=0.003, respectively). The bradycardia incidence in the 0.090 group was significantly higher than the 0.030 (P=0.026) and 0.060 groups (P=0.038). The 0.060 group decreased the first intake by 1.4 hours (P=0.008) and first flatus by 1.1 hours (P=0.004) and postoperative hospital stay by 1 day (P=0.066). Conclusion: The 0.060 µg·kg-1·min-1 norepinephrine infusion combined with goal-directed fluid therapy exhibited adequate intraoperative management and postoperative outcomes.

Intravenous Maintenance Fluid Therapy in the Pediatric Acute and Critical Care Setting: A European Practice Survey. Intravenous Maintenance Fluids in Pediatric Practice: A European Survey

Background: The ideal fluid for intravenous maintenance fluid therapy (IV-MFT) in acutely and critically ill children is controversial and evidence based clinical practice guidelines are lacking. The current prescribing practices remains unknown.Aim: We aimed to describe the current practices and choice of pediatric acute care clinicians in prescribing IV-MFT in the context of acutely and critically ill children with regards to the amount, tonicity, composition, use of balanced fluid and prescribing strategies in various clinical contexts. Method: A cross-sectional electronic survey was emailed in April-May 2021 to pediatric critical care physicians across European and Middle East countries. The survey instrument was developed by an expert multi-professional panel within ESPNIC. The survey instrument included their practice of prescribing the IV-MFT: indication, amount, tonicity, use of balance solutions & composition of IV-MFT.Results: 154 respondents from 35 European and Middle East countries participated in this survey (response rate 64%). Respondents were staff physicians or nurse practitioners in charge of critically ill children. They all indicated that they routinely use a predefined formula to prescribe the amount of an IV-MFT. The use of balanced solution was preferred in case of altered serum Na and Cl levels or metabolic acidosis. 42% of responders (65/153) believed that balanced solutions should always be used. In terms of the indication and the composition of IV-MFT prescribed, responses were heterogenous among centers. 70% of the respondents (n=107) believed there was a gap between the current practice in their unit and what they considered ideal IV-MFT due to the lack of guidelines and inadequate training of health care professionals.Conclusion: Our study showed considerable variability in clinical prescribing practice of IV-MFT in PICUs across Europe and the middle east. There is an urgent need to develop evidence-based guidelines for IV-MFT prescription in acutely and critically ill children.

Hyperspectral Imaging for the Evaluation of Microcirculatory Tissue Oxygenation and Perfusion Quality in Haemorrhagic Shock: A Porcine Study

Background: The ultimate goal of haemodynamic therapy is to improve microcirculatory tissue and organ perfusion. Hyperspectral imaging (HSI) has the potential to enable noninvasive microcirculatory monitoring at bedside. Methods: HSI (Tivita® Tissue System) measurements of tissue oxygenation, haemoglobin, and water content in the skin (ear) and kidney were evaluated in a double-hit porcine model of major abdominal surgery and haemorrhagic shock. Animals of the control group (n = 7) did not receive any resuscitation regime. The interventional groups were treated exclusively with either crystalloid (n = 8) or continuous norepinephrine infusion (n = 7). Results: Haemorrhagic shock led to a drop in tissue oxygenation parameters in all groups. These correlated with established indirect markers of tissue oxygenation. Fluid therapy restored tissue oxygenation parameters. Skin and kidney measurements correlated well. High dose norepinephrine therapy deteriorated tissue oxygenation. Tissue water content increased both in the skin and the kidney in response to fluid therapy. Conclusions: HSI detected dynamic changes in tissue oxygenation and perfusion quality during shock and was able to indicate resuscitation effectivity. The observed correlation between HSI skin and kidney measurements may offer an estimation of organ oxygenation impairment from skin monitoring. HSI microcirculatory monitoring could open up new opportunities for the guidance of haemodynamic management.