Delphi Process for Validation of Fluid Treatment Algorithm for Critically Ill Pediatric Trauma Patients

INTRODUCTION

While intravenous fluid therapy is essential to re-establishing volume status in children who have experienced trauma, aggressive resuscitation can lead to various complications. There remains a lack of consensus on whether pediatric trauma patients will benefit from a liberal or restrictive crystalloid resuscitation approach and how to optimally identify and transition between fluid phases.

METHODS

A panel was comprised of physicians with expertise in pediatric trauma, critical care, and emergency medicine. A three-round Delphi process was conducted via an online survey, with each round being followed by a live video conference. Experts agreed or disagreed with each aspect of the proposed fluid management algorithm on a five-level Likert scale. The group opinion level defined an algorithm parameter's acceptance or rejection with greater than 75% agreement resulting in acceptance and greater than 50% disagreement resulting in rejection. The remaining were discussed and re-presented in the next round.

RESULTS

Fourteen experts from five Level 1 pediatric trauma centers representing three subspecialties were included. Responses were received from 13/14 participants (93%). In round 1, 64% of the parameters were accepted, while the remaining 36% were discussed and re-presented. In round 2, 90% of the parameters were accepted. Following round 3, there was 100% acceptance by all the experts on the revised and final version of the algorithm.

CONCLUSIONS

We present a validated algorithm for intavenous fluid management in pediatric trauma patients that focuses on the de-escalation of fluids. Focusing on this time point of fluid therapy will help minimize iatrogenic complications of crystalloid fluids within this patient population.

Pilot randomized controlled trial of restricted versus liberal crystalloid fluid management in pediatric post-operative and trauma patients

BACKGROUND

Intravenous (IV) fluid therapy is essential in the treatment of critically ill pediatric surgery and trauma patients. Recent studies have suggested that aggressive fluids may be detrimental to patients. Prospective studies are needed to compare liberal to restricted fluid management in these patients. The primary objective of this pilot trial is to test study feasibility-recruitment and adherence to the study treatment algorithm.

METHODS

We conducted a two-part pilot randomized controlled trial (RCT) comparing liberal to restricted crystalloid fluid management in 50 pediatric post-operative (1-18 years) and trauma (1-15 years) patients admitted to our pediatric intensive care unit (PICU). Patients were randomized to a high (liberal) volume or low (restricted) volume algorithm using unblinded, blocked randomization. A revised treatment algorithm was used after the 29th patient for the second part of the RCT. The goal of the trial was to determine the feasibility of conducting an RCT at a single site for recruitment and retention. We also collected data on the safety of study interventions and clinical outcomes, including pulmonary, infectious, renal, post-operative, and length of stay outcomes.

RESULTS

Fifty patients were randomized to either liberal (n = 26) or restricted (n = 24) fluid management strategy. After data was obtained on 29 patients, a first study analysis was performed. The volume of fluid administered and triggers for intervention were adapted to optimize the treatment effect and clarity of outcomes. Updated and refined fluid management algorithms were created. These were used for the second part of the RCT on patients 30-50. During this second study period, 54% (21/39, 95% CI 37-70%) of patients approached were enrolled in the study. Of the patients enrolled, 71% (15/21, 95% CI 48-89%) completed the study. This met our a priori recruitment and retention criteria for success. A data safety monitoring committee concluded that no adverse events were related to study interventions. Although the study was not powered to detect differences in outcomes, after the algorithm was revised, we observed a non-significant trend towards improved pulmonary outcomes in patients on the restricted arm, including decreased need for and time on oxygen support and decreased need for mechanical ventilation.

CONCLUSION

We demonstrated the feasibility and safety of conducting a single-site RCT comparing liberal to restricted crystalloid fluid management in critically ill pediatric post-operative and trauma patients. We observed trends in improved pulmonary outcomes in patients undergoing restricted fluid management. A definitive multicenter RCT comparing fluid management strategies in these patients is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04201704 . Registered 17 December 2019-retrospectively registered.

Sustained Delivery of SB-431542, a Type I Transforming Growth Factor Beta-1 Receptor Inhibitor, to Prevent Arthrofibrosis

Fibrosis of the knee is a common disorder resulting from an aberrant wound healing response and is characterized by extracellular matrix deposition, joint contraction, and scar tissue formation. The principal regulator of the fibrotic cascade is transforming growth factor beta-1 (TGF-β1), a factor that induces rapid proliferation and differentiation of resident fibroblasts. In this study, we demonstrate successful inhibition of TGF-β1-driven myofibroblastic differentiation in human fibroblast-like synoviocytes using a small molecule TGF-β1 receptor inhibitor, SB-431542. We also demonstrate successful encapsulation of SB-431542 in poly(D,L-lactide-co-glycolide) (PLGA) as a potential prophylactic treatment for arthrofibrosis and characterize drug release and bioactivity in a three-dimensional collagen gel contraction assay. We assessed the effects of TGF-β1 and SB-431542 on cell proliferation and viability in monolayer cultures. Opposing dose-dependent trends were observed in cell proliferation, which increased in TGF-β1-treated cultures and decreased in SB-431542-treated cultures relative to control (p < 0.05). SB-431542 was not cytotoxic at the concentrations studied (0-50 μM) and inhibited TGF-β1-induced collagen gel contraction in a dose-dependent manner. Specifically, TGF-β1-treated gels contracted to 18% ± 1% of their initial surface area, while gels treated with TGF-β1 and ≥10 μM SB-431542 showed no evidence of contraction (p < 0.0001). Upon removal of the compound, all gels contracted to control levels after 44 h in culture, necessitating sustained delivery for prolonged inhibition. To this end, SB-431542 was encapsulated in PLGA microspheres (SBMS) that had an average diameter of 87.5 ± 24 μm and a loading capacity of 4.3 μg SB-431542 per milligram of SBMS. Functional assessment of SBMS revealed sustained inhibition of TGF-β1-induced gel contraction as well as hallmark features of myofibroblastic differentiation, including α-smooth muscle actin expression and connective tissue growth factor production. These results suggest that SB-431542 may be used to counter TGF-β1-driven events in the fibrotic cascade in the knee cartilage.

P2716Correlation between computed tomography derived ischemia index and conventional fractional flow reserve

Background

Computed tomography (CT) derived ischemia index is a novel tool to determine the significance of coronary artery disease, however, its ability to identify myocardial ischemia has not been examined.

Methods

From Jan. 2013 to Dec. 2015, 14,000 patients underwent ECG-gated CT coronary angiography for suspected coronary artery disease. From Jan. 2013 to Jan. 2016, 483 patients (589 vessels) underwent conventional FFR to assess myocardial ischemia. Among those, FFR was assessed in 148 patients (167 vessels) within 30 days after CT coronary angiography. We further excluded 24 patients with prior stenting or bypass grafting, 3 patients with multiple MDCT or FFR, and 6 patients with insufficient datasets. Finally, we included 117 patients (127 vessels) to assess the correlation between CT derived ischemia index and conventional FFR.

CT derived ischemia index was calculated as follows: left ventricular volume distally to the coronary artery lumen (cm3)/coronary artery lumen area (mm2). Left ventricular volume was automatically determined using Advantage Workstation and divided according to the nearest coronary artery tree. Center of coronary arteries were manually traced and contours of coronary artery lumen were automatically depicted. CT derived ischemia index was calculated at approximately every 0.625mm point of coronary artery. Moving median of consecutive 5 points (approximately 3.125mm) were used to remove outliers. Maximum value of CT derived ischemia index per coronary artery segment was calculated to determine the significance of coronary artery disease.

Results

Mean age was 71.3±10.5 years and 63.8% of patients were male. Coronary angiography was performed to assess conventional FFR at the median of 13 days (IQR 7 to 18 days) after CT. Majority of the target vessel was left anterior descending artery (71.7%), followed by right coronary artery (14.2%), left circumflex artery (13.4%) and left main coronary artery (0.8%). According to the quantitative coronary angiography, minimum lumen diameter was 1.47±0.32mm with percent diameter stenosis of 48.3±10.4%. Median FFR value was 0.83 (IQR 0.76 to 0.88) and positive test for myocardial ischemia (FFR <0.80) was observed in 42 vessels (33.1%). Maximum CT derived ischemia index per segment ranged from 1.825 to 57.296 (median 8.333, IQR 4.911 to 14.484). There was a negative correlation between CT derived ischemia index and FFR (r=−0.319, 95% confidence interval −0.467 to −0.153, P<0.001). Receiver operating characteristic analysis indicated CT derived ischemia index of 9.962 has 76.2% sensitivity and 70.6% specificity for the presence of FFR<0.80 (AUC 0.73, 95% CI 0.64 to 0.82).

Conclusions

A novel tool of CT derived ischemia index has a significant negative correlation with conventional FFR in lesions with mild to moderate stenosis. Larger multicenter prospective studies are needed to fully determine the impact of CT derived ischemia index.

Increased Bone Morphogenetic Protein Signaling in the Cutaneous Vasculature of Patients with Calciphylaxis

BACKGROUND

The objective of this study was to investigate the role of bone morphogenetic protein (BMP) signal transduction in the pathogenesis of calciphylaxis.

METHODS

Skin biopsy specimens were obtained from 18 patients with, and 12 patients without, calciphylaxis. Tissue sections were stained with antibodies directed against BMP effector proteins phosphorylated-SMAD (p-SMAD) 1/5/9, inhibitor of DNA 1 (Id1), inhibitor of DNA 3 (Id3), and Runx2. The intensity of staining was scored semi-quantitatively as strong versus weak or absent.

RESULTS

Of the 18 patients with calciphylaxis (mean age: 59 ± 8 years), 9 were women and 15 had end-stage renal disease. Of the 12 control patients (mean age: 57 ± 10 years), 8 were women and 8 had end-stage renal disease. Strong staining for p-SMAD 1/5/9 was detected in blood vessels from all calciphylaxis patients. In 1 patient with calciphylaxis, strong staining for p-SMAD 1/5/9 was detected in a blood vessel that did not have evidence of calcification. Id1 and Id3 immunoreactivity was detected in blood vessels from all 12 patients with calciphylaxis that were tested. Runx2 staining was detected in all 6 patients with calciphylaxis who were tested. p-SMAD 1/5/9 immunoreactivity was weak or absent in blood vessels of 10 of the 12 control samples.

CONCLUSIONS

The BMP signal transduction pathway is activated in the cutaneous vasculature of calciphylaxis patients. The ability to detect p-SMAD 1/5/9, Id1, and Id3 in cutaneous vasculature may assist in the diagnosis of calciphylaxis. As BMP signaling inhibitors become available, this pathway may serve as a future therapeutic target for calciphylaxis.

Development of recombinant viral insecticides by expression of an insect-specific toxin and insect-specific enzyme in nuclear polyhedrosis viruses

As supplements to classical chemical insecticides, two approaches to develop recombinant baculovirus insecticides are described. In one approach an insect-specific toxin is expressed leading to a dramatic reduction in time to death. In the second approach an insect juvenile hormone esterase is expressed which leads to a reduction in feeding. Modifications of the wildtype esterase led to viruses which reduced the time to death as effectively as did the toxin-expressing virus. In both cases existing recombinant viruses are viewed as leads, and approaches to further improvement in the engineered viruses are suggested. Many of these approaches are based on analogy with the development of classical synthetic insecticides. Using these viruses as examples, the potential utility and limitations of recombinant viruses and other biological insecticides are discussed.

Intramolecular deuterium isotope effect and enantiotopic differentiation in oxidative demethylation of chiral [monomethyl-d3]methoxychlor in rat liver microsomes

Intramolecular deuterium kinetic isotope effects on the O-demethylation of methoxychlor [2,2-bis-(4-methoxyphenyl)-1,1,1-trichloroethane] were measured in liver microsomes taken from rats treated with phenobarbital or beta-naphthoflavone and from untreated rats. The substrates were (R)-, (S)- and racemic [monomethyl-d3]methoxychlor, and the ratio of [d3]- to [d0]-mono-O-demethylated metabolites was measured by GC-MS selected-ion monitoring. The magnitude of the observed ratio of [d3]- to [d0]-metabolites in each microsomal preparation was largest on the reaction of the (S)-substrate, followed by racemic substrate, and then (R). Each value is a composite of the intramolecular kinetic isotope effect and enantiotopic differentiation during the reaction. Each intramolecular isotope effect value estimated from these values was smaller than the reported intrinsic value. A relatively slow intramolecular interchange of two methoxyl groups in the methoxychlor molecule in the enzyme-substrate complex was indicated during the reaction. There also was evidence of high enantiotopic differentiation.