Anaemia among intensive care unit survivors and association with days alive and at home: an observational study

Anaemia is highly prevalent at the time of intensive care unit discharge and is persistent for a high proportion of intensive care unit survivors. Whether anaemia is a driver of impaired recovery after critical illness is uncertain. The aim of this study was to test the hypothesis that, in adult intensive care survivors, anaemia at the time of intensive care unit discharge independently predicts decreased days at home-90. This retrospective cohort study was conducted in a tertiary intensive care unit in Perth, Western Australia. All patients aged ≥ 16 years, discharged alive from their index intensive care unit admission and without documented treatment limitations were included. Median (IQR [range]) age of the 6358 participants was 61 (46–72 [16–95]) years and included 3385 (53.2%) unplanned admissions. Intensive care unit discharge with a haemoglobin concentration < 100 g.l^-1 occurred in 2886 (45.4%) patients, a threshold that identified a cohort with significantly lower days at home-90 (median (IQR [range]) 80 (64–85 [0–90]) days vs. 85 (77–88 [0–90]) days (median difference 5 days, 95%CI 4.4–5.5, p < 0.0001). The association followed a severity-response relationship with more severe anaemia predicting lower days at home-90. When accounting for prespecified covariates including admission haemoglobin concentration and red blood cell transfusion, anaemia at intensive care unit discharge remained a significant predictor of decreased days at home-90, relative risk 0.96 (0.93–0.98), p < 0.002. These findings support the need for interventional trials investigating whether this risk is modifiable.     

DVPV系统三维影像及虚拟现实导航在泌尿外科复杂手术的应用

目的探讨DVPV数字化手术辅助影像导航技术在泌尿外科复杂手术中的应用价值。方法应用DVPV系统的三维可视化数字重建、虚拟现实应用、全息医疗专业影像平台,在普通CT或MRI数据的基础上进行三维图像重建,术前制定最优的手术方案,术中通过虚拟现实眼镜观看病灶影像并为手术操作进行导航。记录手术操作时间、疗效与围手术期并发症。结果 7例手术均顺利完成。3例肾血管平滑肌瘤(2例为较大体积,1例为肾门肿瘤)被完整切除,患侧肾脏均被保留。无损伤肾门血管和肾盂,平均出血量30 ml,平均手术时间105 min。在肾结石病例中,术中影像导航下避开肾脏重要血管,切开肾皮质的薄弱处取净鹿角型结石,手术时间120 min,出血量约50 ml。大体积中叶前列腺癌用腹腔镜技术完成根治术,出血量约75 ml。前列腺巨大囊性肿物行经直肠穿刺抽液+肿物活检术。肾上腺肿瘤用腹腔镜切除。全部患者平均住院日4.5 d,术中术后无并发症,恢复良好。结论 DVPV数字化手术影像导航系统有助于术前疾病评估,明确病变位置,术中虚拟现实影像导航,可提高医师操作的精准性,降低手术出血量、操作难度与风险,缩短手术时间,让患者获益。     

Effect of different pressure magnitudes on hypertrophic scar in a Chinese population

Introduction

This study aimed to investigate the effect of different pressure magnitudes on treatment outcomes of hypertrophic scars, and determine pressure loss over time.

Methods

A randomized clinical trial was adopted. 53 hypertrophic scar samples from 17 Chinese participants were recruited and randomly assigned into a high pressure group (20–25 mmHg) and low pressure group (10–15 mmHg) for a five-month intervention program. The scars were assessed objectively before intervention and monthly after intervention for thickness, color (redness, yellowness and lightness) and scar pliability. Pressure magnitude at each assessment was also measured. Two-way repeated ANOVA was used to compare for differences between groups.

Results

The results showed that both levels of pressure produced reduction in scar thickness and redness, but the improvement in the high pressure group was statistically better than that of the counterpart (both p < 0.05). Monthly pressure measurement revealed that pressure loss in the high pressure group was more severe. However, no major changes in other color parameters and pliability were observed for both the groups.

Conclusion

High pressure was demonstrated to be more effective for scar management, but it was also more prone to higher pressure loss. Pressure therapy integrated with regular monitoring of the interface pressure is suggested to improve its therapeutic efficacy.     

Dynamic changes of indoleamine 2,3-dioxygenase of Kupffer cells in rat liver transplant rejection and tolerance

Aims

To study the dynamic changes and the immunologic role of indoleamine 2, 3-dioxygenase (IDO) in Kupffer cells (KCs) after rat liver transplantation.

Methods

Animals were randomly divided into two groups: a rejection group (REJ; LEW to BN) and a tolerance group (TOL; BN to LEW). Liver morphological changes were observed optically with hematoxylin/eosin staining. KCs were isolated from recipients. mRNA and protein expressions of IDO were detected by real-time polymerase chain reaction and Western blotting at 1, 3, 5, and 7 days after transplantation.

Results

The levels of IDO mRNA and protein in KCs of TOL groups were similar to those in REJ groups at day 1 posttransplantation. However, the expression of IDO mRNA and protein time-dependently increased to much higher levels in the TOL than the in REJ groups at 3, 5, and 7 days posttransplantation (P < .05). The peak was observed at 7 days.

Conclusions

The IDO level of KCs was closely associated with immune tolerance induction. IDO-mediated immune modulation appears to be an attractive means to assess transplant tolerance induction.     

Convergence Rate Analysis for Deep Ritz Method

Using deep neural networks to solve PDEs has attracted a lot of attentions recently. However, why the deep learning method works is falling far behind its empirical success. In this paper, we provide a rigorous numerical analysis on deep Ritz method (DRM) [47] for second order elliptic equations with Neumann boundary conditions. We establish the first nonasymptotic convergence rate in $H^1$ norm for DRM using deep networks with ${\rm ReLU}^2$ activation functions. In addition to providing a theoretical justification of DRM, our study also shed light on how to set the hyperparameter of depth and width to achieve the desired convergence rate in terms of number of training samples. Technically, we derive bound on the approximation error of deep ${\rm ReLU}^2$ network in $C^1$ norm and bound on the Rademacher complexity of the non-Lipschitz composition of gradient norm and ${\rm ReLU}^2$ network, both of which are of independent interest.     

Magnesium chloride and ruthenium red attenuate the antiallodynic effect of intrathecal gabapentin in a rat model of postoperative pain

BACKGROUND: Gabapentin, a gamma-aminobutyric acid analog anticonvulsant, has been shown to possess antinociceptive effects in animal models and clinical trials. An endogenous binding site of [3H]gabapentin has been revealed to be the alpha(2)delta subunit of voltage-dependent Ca2+ channels. Magnesium chloride, ruthenium red, and spermine have been shown to modulate [3H]gabapentin binding to this binding site in vitro. In this study, the authors examined whether intrathecal magnesium chloride, ruthenium red, or spermine could affect the antiallodynic effect of intrathecal gabapentin in a rat model of postoperative pain. METHODS: Under isoflurane anesthesia, male Sprague-Dawley rats received an incision over the plantar surface of the right hind paw to produce punctate mechanical allodynia. Withdrawal thresholds to von Frey filament stimulation near the incision site were measured before incision, 2 h after incision, and every 30 min after intrathecal coadministration of gabapentin with normal saline or different doses of magnesium chloride, ruthenium red, or spermine for 2 h. RESULTS: Intrathecal gabapentin (30, 100, 200 microg) dose-dependently reduced incision-induced allodynia. Hexahydrated magnesium chloride (5, 10, 20 microg) and ruthenium red (0.2, 2, 20 ng) noncompetitively inhibited the antiallodynic effect of gabapentin. Spermine at doses not inducing motor weakness (30, 60 microg) did not affect the antiallodynic effect of gabapentin. The antiallodynic effect of intrathecal morphine (1.5 microg) was not affected by hexahydrated magnesium chloride (20 microg), ruthenium red (20 ng), or spermine (60 microg). CONCLUSIONS: These results provide behavioral evidence to support that the alpha(2)delta subunit of Ca2+ channels may be involved in the antiallodynic action of intrathecal gabapentin in the postoperative pain model.     

Early failure of precoated femoral components in primary total hip arthroplasty

BACKGROUND: In an effort to decrease the rate of aseptic loosening, certain cemented femoral components were designed to have a roughened or textured surface with a methylmethacrylate precoating. Reports differ as to whether this step has increased or decreased the rate of failure. This study was designed to evaluate this issue. METHODS: Five hundred and fourteen hips treated with a cemented Harris Precoat stem (Zimmer, Warsaw, Indiana) were evaluated clinically and radiographically and compared with 254 hips treated with an uncoated Harris Design-2 stem (Howmedica, East Rutherford, New Jersey). Prostheses that had been removed at revision were examined. The cementing and surgical techniques were identical and the population demographics were similar for these two groups. RESULTS: The mean durations of follow-up were 8.4 and 13.5 years for the Precoat and uncoated Design-2 stems, respectively. At those times, at least forty-nine (9.5%) of the 514 Precoat components and at least ten (3.9%) of the 254 uncoated Design-2 stems had failed (p = 0.006). Five Precoat stems fractured, and no uncoated Design-2 stems fractured. Component failure was associated with use in young, active, heavy men with a diagnosis of avascular necrosis and generally with the use of smaller components. The cementing technique was satisfactory in the majority of the patients, and there were no qualitative differences in cementing technique between the hips that failed and those that did not. The mechanisms of failure of the Precoat prostheses included bone-cement loosening, focal osteolysis, stem fracture, and prosthesis-cement debonding. Fractures of smaller components occurred as a result of fatigue failure and were associated with good distal fixation but proximal stem loosening. CONCLUSIONS: The rate of failure of roughened, precoated, cemented femoral components was considerably higher and occurred earlier than that of femoral components that were neither textured nor precoated with methylmethacrylate. Younger patients with avascular necrosis had a higher risk of failure; however, this factor alone did not completely explain the differences in outcome between these two components. The causes of aseptic loosening are multifactorial and may be related to component design and size as well as to precoating and surface finish.     

Transverse plane pelvic rotation in adolescent idiopathic scoliosis: primary or compensatory?

Several studies have suggested that the pelvis is involved in the etiology or pathogenesis of adolescent idiopathic scoliosis (AIS). The purpose of this retrospective, cross-sectional radiographic study is to identify any correlation between the transverse plane rotational position of the pelvis in stance and operative-size idiopathic or congenital scoliosis deformities, using Scheuermann’s kyphosis and isthmic spondylolisthesis patients for comparison. The hypothesis tested was that the direction of transverse pelvic rotation is the same as that for a thoracic scoliosis. As a group, AIS patients had a significant transverse plane pelvic rotation in the same direction as the thoracic curve. When subdivided into the six Lenke curve patterns, this was true for the groups with a major thoracic curve: thoracic (1), double thoracic (2) and double curve patterns (3). It was not true for patterns with a major thoracolumbar/lumbar curve: single thoracolumbar/lumbar (5) and double thoracic-thoracolumbar/lumbar (6). Nor was it true for triple (4) curves. The Lenke 1 and 2 major thoracic curves without compensatory thoracolumbar/lumbar curves did not have the predicted pelvic rotation. All congenital scoliosis patients studied had main thoracic curves and significant transverse plane pelvic rotation in the same direction as the thoracic curve. There was no transverse plane pelvic rotation in the Scheuermann’s kyphosis or isthmic spondylolisthesis patients. We interpret these findings as consistent with a compensatory rotation of the pelvis in the same direction as the main thoracic curve in most patients with a compensatory thoracolumbar/lumbar curve as well as in patients with main thoracic congenital scoliosis.