Arterial stiffness, endothelial function and microcirculatory reactivity in healthy young males

Large (C1) and small (C2) arterial stiffness has been suggested to parallel endothelial reactivity and has led researchers to suggest parameters of arterial stiffness may be alternative measures to brachial sonographic assessments of flow-mediated dilatation (FMD). However, past studies comparing these measures can be criticized. In addition to %FMD responses, we recorded concurrent hyperaemic responses of the microcirculation and both were compared with C1 and C2. Twenty-nine subjects 18-30 years of age were investigated. Radial blood pressure was recorded with a tonometer. Pulse waveform analysis was performed to calculate C1 and C2. These were compared with %FMD responses and responses of finger flux measured by laser Doppler fluxmetry (LDF); pulsatile finger volume measured by photoplethysmography (PPG); and palm skin temperature measured by infrared thermography (Tpalm) (i.e. microcirculatory responses). Responses were determined as % changes from control. We only found weak relationships between C1 and %FMD (r=0.4, P=0.04); C2 and %PPG (r=0.38, P=0.07); and C2 and %LDFdorsal (r=-0.38; P=0.04). Responses of %FMD weakly parallel those of C1. Neither C2 nor C1 are viable indicators of endothelial or microcirculatory reactivity (i.e. hyperaemic or venous constriction) in healthy, resting young males. These findings refute the claims that C1 and C2 are substitute measures to sonographic assessments of brachial FMD.     

Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews

BACKGROUND AND OBJECTIVES: Studies of diagnostic accuracy most often report pairs of sensitivity and specificity. We demonstrate the advantage of using bivariate meta-regression models to analyze such data. METHODS: We discuss the methodology of both the summary Receiver Operating Characteristic (sROC) and the bivariate approach by reanalyzing the data of a published meta-analysis. RESULTS: The sROC approach is the standard method for meta-analyzing diagnostic studies reporting pairs of sensitivity and specificity. This method uses the diagnostic odds ratio as the main outcome measure, which removes the effect of a possible threshold but at the same time loses relevant clinical information about test performance. The bivariate approach preserves the two-dimensional nature of the original data. Pairs of sensitivity and specificity are jointly analyzed, incorporating any correlation that might exist between these two measures using a random effects approach. Explanatory variables can be added to the bivariate model and lead to separate effects on sensitivity and specificity, rather than a net effect on the odds ratio scale as in the sROC approach. The statistical properties of the bivariate model are sound and flexible. CONCLUSION: The bivariate model can be seen as an improvement and extension of the traditional sROC approach.     

Long term outcome in subfertile couples with isolated cervical factor

Objective

A previous randomized clinical trial (RCT) compared immediate treatment with intrauterine insemination (IUI) to expectant management for six months in subfertile couples with an isolated cervical factor. That study showed higher ongoing pregnancy rates in couples receiving intrauterine insemination. The current study compared the long-term effectiveness and costs of this intervention.

Study design

We followed all couples (N = 99) who were previously included in the RCT for three years after randomization and registered pregnancies and treatments. After the initial trial period, couples in both groups were offered further treatment according to local protocol. The primary outcome was an ongoing pregnancy after three years.

Results

After three years, there were 36 ongoing pregnancies in the immediate IUI group (N = 51 couples) and 38 ongoing pregnancies in the expectant management group (N = 48 couples). The ongoing pregnancy rates were 71% and 79% respectively (RR 0.89 (95% confidence interval (CI) 0.7–1.1)).

Conclusions

In couples with an isolated cervical factor, a treatment strategy including immediate treatment with IUI does not result in higher ongoing pregnancy rates on the long term. Initial expectant management is therefore justified in these couples and identifying a cervical factor by a post-coital test is unnecessary.     

Congenital left atrial appendage ostial stenosis in an extremely premature infant diagnosed by transthoracic echocardiography

Congenital left atrial appendage ostial stenosis is a very rare congenital cardiac condition. We present the case of an extremely premature infant with congenital left atrial appendage ostial stenosis diagnosed by transthoracic echocardiographic imaging.     

A failure in the medication delivery system—how disclosure and systems investigation improve patient safety

A recent medication error at Vanderbilt University Medical Center contributed to the death of a patient. The ensuing criminal indictment of the administering nurse has shaken the medical community. This has led to clinical staff questioning whether they can disclose patient safety incidents without fear of criminal prosecution. However, because of the publicity of this case, hospitals can benefit from the lessons learned and mitigate the risk of this and similar events at their facilities. To uncover the most impactful and relevant safety recommendations, the Vanderbilt case is examined from a systems investigation perspective using the available public information gathered from media reports, the Tennessee Bureau of Investigation report, and Vanderbilt's corrective action plan submitted to CMS. We present an example of how hospitals can benefit from disclosure: Henry Ford Health used the Vanderbilt case study as part of its medication safety continuous improvement initiatives, which are underpinned by available medication safety recommendations from the Institute for Safe Medication Practices. Using this experience and the lessons learned from the Vanderbilt case, a proactive action plan is presented for hospitals nationwide to prevent the recurrence of this medication error. Without disclosure, these analyses and safety recommendations would not have been possible.     

Transfusion of red blood cells in venoarterial extracorporeal membrane oxygenation: A multicenter retrospective observational cohort study

Background

Evidence-based recommendations for transfusion in patients with venoarterial extracorporeal membrane oxygenation (VA ECMO) are scarce. The current literature is limited to single-center studies with small sample sizes, therefore complicating generalizability. This study aims to create an overview of red blood cell (RBC) transfusion in VA ECMO patients.

Methods

This international mixed-method study combined a survey with a retrospective observational study in 16 centers. The survey inventoried local transfusion guidelines. Additionally, retrospective data of all adult patients with a VA ECMO run >24 h (January 2018 until July 2019) was collected of patient, ECMO, outcome, and daily transfusion parameters. All patients that received VA ECMO for primary cardiac support were included, including surgical (i.e., post-cardiotomy) and non-surgical (i.e., myocardial infarction) indications. The primary outcome was the number of RBC transfusions per day and in total. Univariable logistic regressions and a generalized linear mixed model (GLMM) were performed to assess factors associated with RBC transfusion.

Results

Out of 419 patients, 374 (89%) received one or more RBC transfusions. During a median ECMO run of 5 days (1st–3rd quartile 3–8), patients received a median total of eight RBC units (1st–3rd quartile 3–17). A lower hemoglobin (Hb) prior to ECMO, longer ECMO-run duration, and hemorrhage were associated with RBC transfusion. After correcting for duration and hemorrhage using a GLMM, a different transfusion trend was found among the regimens. No unadjusted differences were found in overall survival between either transfusion status or the different regimens, which remained after adjustment for potential confounders.

Conclusion

RBC transfusion in patients on VA ECMO is very common. The sum of RBC transfusions increases rapidly after ECMO initiation, and is dependent on the Hb threshold applied. This study supports the rationale for prospective studies focusing on indications and thresholds for RBC transfusion.