Conventional parameters are often inadequate to describe the dynamic flow changes in microcirculation. We used a novel approach to characterize oscillatory flow conditions in a canine model of hemorrhagic shock. Microcirculation in the ileal mucosal villi was visualized using intravital microscopy with the orthogonal polarization spectral imaging technique. The distribution of red blood cell velocity (RBCV) was estimated from the relative time periods of observed RBCV, and the average RBCV (A-RBCV) and its SD were then computed from the first and second moments of the RBCV distribution, respectively. Hemorrhagic shock (for 60 min) was followed by resuscitation with saline, hypertonic saline-Dextran solution (HSD, 7.2% NaCl-10% Dextran, 4 mL/kg), or HSD supplemented with the selective endothelin-A receptor antagonist ETR-p1/fl peptide (100 nmol/kg), respectively. The macrohemodynamic derangement (70% decrease in cardiac index and ileal blood flow) during shock was associated with the appearance of flow motion in the villi and an enhanced endothelin-1 release. The calculated A-RBCV was decreased by 40%. At resuscitation onset, continuous flow periods were transiently seen in 33%, 40%, and 50% of the experiments after saline, HSD, and HSD + ETR p1/fl treatment, respectively. HSD with or without endothelin-A antagonist treatment resulted in an increased relative duration of high-flow periods (by 20%) and a significant, 20% to 40% rise in A-RBCV. These results demonstrate that time-wise variability of RBCV should be used for the analysis of oscillatory flow conditions. The probabilistic estimation of A-RBCV provides a quantitative basis for comparison of the effectiveness of different resuscitation or vasoactive strategies.

Background The potential advantages of hydroxyapatite (HA)-coated cementless total knee arthroplasty (TKA) implants are bone stock preservation and biological fixation. Studies comparing the outcomes of HA-coated cementless, non HA-coated cementless (uncemented) and cemented TKA implants reported contradictory data. Our aim was to provide a comparison of the effects of HA coating of tibial stem on the stability and functionality of TKA implants. Methods A systematic literature search was performed using MEDLINE, Scopus, EMBASE and the CENTRAL databases up to May 31st, 2019. The primary outcome was Maximum Total Point Motion (MTPM) of the tibial stem. This parameter is determined by radiosterometric analysis and refers to the migration pattern of the prosthesis stems. The clinical outcomes of the implanted joints were evaluated by the Knee Society Knee Score (KSS) and the Knee Society Function Score (KFS). Weighted mean difference (WMD) with 95% confidence interval (CI) were calculated with the random-effects model. Results Altogether, 11 randomized controlled trials (RCTs) with 902 patients for primary TKA implants were included. There was a statistically significant difference in the MTPM values with the use of HA-coated and uncoated uncemented implants (WMD = +0.28, CI: +0.01 to +0.56, P<0.001). However, HA-coated stems showed significantly higher migration when compared with the cemented prostheses (WMD =-0.29, CI:-0.41 to-0.16, P<0.001). The KSS values of HA-coated implants were significantly higher than those for the uncemented PLOS ONE

ObjectivesHeart rate (HR) is one of the physiological variables in the early assessment of trauma-related haemorrhagic shock, according to Advanced Trauma Life Support (ATLS). However, its efficiency as predictor of mortality is contradicted by several studies. Furthermore, the linear association between HR and the severity of shock and blood loss presented by ATLS is doubtful. This systematic review aims to update current knowledge on the role of HR in the initial haemodynamic assessment of patients who had a trauma.DesignThis study is a systematic review and meta-regression that follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations.Data sourcesEMBASE, MEDLINE, CENTRAL and Web of Science databases were systematically searched through on 1 September 2020.Eligibility criteriaPapers providing early HR and mortality data on bleeding patients who had a trauma were included. Patient cohorts were considered haemorrhagic if the inclusion criteria of the studies contained transfusion and/or positive focused assessment with sonography for trauma and/or postinjury haemodynamical instability and/or abdominal gunshot injury. Studies on burns, traumatic spinal or brain injuries were excluded. Papers published before January 2010 were not considered.Data extraction and synthesisData extraction and risk of bias were assessed by two independent investigators. The association between HR and mortality of patients who had a trauma was assessed using meta-regression analysis. As subgroup analysis, meta-regression was performed on patients who received blood products.ResultsFrom a total of 2017 papers, 19 studies met our eligibility criteria. Our primary meta-regression did not find a significant relation (p=0.847) between HR and mortality in patients who had a trauma with haemorrhage. Our subgroup analysis included 10 studies, and it could not reveal a linear association between HR and mortality rate.ConclusionsIn accordance with the literature demonstrating the multiphasic response of HR to bleeding, our study presents the lack of linear association between postinjury HR and mortality. Modifying the pattern of HR derangements in the ATLS shock classification may result in a more precise teaching tool for young clinicians.

<b><i>Purpose:</i></b> The aim was to examine the predictive value of the hypovolemic shock classification currently accepted by the Advanced Trauma Life Support (ATLS) program over the previous one, which used only vital signs (VS) for patient allocation. The primary outcome was 30-day mortality; as secondary outcome, heart rate (HR), systolic blood pressure (SBP), Glasgow Coma Scale (GCS) and base deficit (BD) data were compared and investigated in terms of mortality prediction. <b><i>Methods:</i></b> Retrospective analysis at a level I trauma center between 2014 and 2019. Adult patients treated by trauma teams were allocated into severity classes (I–IV) based on the criteria of the current and previous ATLS classifications, respectively. The prognostic values for the classifications were determined with Fisher’s exact test and χ² test for independence, and compared with the 2-proportion Z test. The individual variables were analyzed with receiver-operating characteristic (ROC) analyses. <b><i>Results:</i></b> A total of 156 patients met the inclusion criteria. Mortality was effectively predicted by both classifications, and there was no statistically significant difference between the predictive performances. According to ROC analyses, GCS, BD and SBP had significant prognostic values while HR change was ineffective in this regard. <b><i>Conclusions:</i></b> The currently used ATLS shock classification does not appear to be superior to the VS-based previous classification. GCS, BD and SBP are useful parameters to predict the prognosis. Changes in HR do not reflect the clinical course accurately; thus, further studies will be needed to determine the value of this parameter in trauma-associated hypovolemic-hemorrhagic shock conditions.

Introduction: We examined the endosteal and periosteal circulations in a patient with fracture non-union who had undergone excessive osteosynthesis applications (two long plates had been placed medially and laterally on the left tibia extending from the proximal 2/7 to the distal 6/7 parts of the bone, while a tibial component of a total knee prosthesis with a long stem had been inserted at the same time). Methods: Concomitant perfusion changes were determined in the anterolateral and anteromedial periosteal sheath of the non-united bone ends and intramedullary nearest the osteosynthesis materials during their surgical removal on re-operation. The blood flow in the periosteum and endosteum was recorded by a laser-Doppler flowmetric device using a novel approach. Control measurements were made at identical points of the right tibia. Results: Considerably lower blood flow values were measured along the tibial periosteal region of the re-operated limb than on the contralateral side (the average perfusion unit (PU) was 76 vs. 106 PU, respectively). Perfusion values were markedly lower in the endosteal region (average values of approx. 30 PU) in the control tibia and were even more diminished in the re-operated tibial endosteum (average 9 PU). Conclusions: Our study was conducted to characterize the microcirculatory changes of a long bone in response to intramedullary implantation and to provide quantitative data on the insufficiency of local perfusion in a patient with fracture non-union. Our results highlight the association between local perfusion failure and the unfavorable outcome (i.e. fracture non-union), confirming that the vital aspects of the microcirculation should not be disregarded when aiming for mechanical stability. Microcirculatory measurements constitute a new area of improvement in planning the adequate treatment for fracture non-unions with an unclear aetiology. Further refinement of the laser-Doppler technique could have potential benefits for bone surgery and postoperative trauma care in the future.