N-Dimethylisopropyl propranolol (DMP) is a quaternary derivative which lacks significant beta-adrenergic blocking and local anesthetic effects. It has been reported, nonetheless, to be effective in treating experimental arrhythmias and in limiting the extent of ST-segment elevations following experimental coronary occlusion. The present study examined the effects of DMP on the hemodynamics and myocardial oxygen demands of anesthetized dogs. After a single dose of 3 mg/kg, heart rate fell from 146 +/- 8 to 124 +/- 6 beats/min (P less than 0.0025), and aortic systolic pressure fell from 151 +/- 11 to 141 +/- 9 mm Hg (0.05 less than P less than 0.10), resulting in a 16.8% reduction in the tension-time index. Stroke volume was reduced by 10% despite a 54% increase in left ventricular end-diastolic pressure, suggesting a negative inotropic effect. This was supported by a decrease in maximum extrapolated contractile element velocity from 9.10 +/- 1.05 to 6.61 +/- 65 units/sec (P less than 0.0025). Myocardial oxygen consumption was reduced from 12.0 +/- 1.4 to 9.9 +/- 1.5 ml/min/100 g tissue (P less than 0.05). Myocardial oxygen extraction was unchanged, indicating that the decrease in oxygen consumption resulted from a reduction in myocardial oxygen demand. When heart rate and systolic pressure were artificially restored to control levels, after the administration of DMP, myocardial oxygen consumption remained significantly below the control level. DMP, therefore, appeared to reduce myocardial oxygen demands primarily by its negative inotropic effect. This drug may have application in the treatment of ischemic heart disease.

An elastohydrodynamic lubrication model is presented for the coupled problem of a hydrodynamic lubricating fluid in an elastic structure that includes distributed structural inertia. The problem is formulated and the governing equations solved with the finite element method for an illustrative journal bearing subject to dynamic loading. Inertia effects are demonstrated through comparisons with an existing quasi-static model. While it is true that structural inertia can be neglected without significant loss of accuracy for many journal bearing applications, the new model presented does capture effects of distributed structural inertia where such effects are important and exhibits improvements over existing methods with respect to numerical stability.

Purpose: The purpose of this study is to identify gaps in support for parents of children with Hypoplastic Left Heart Syndrome. Design and methods: Using a mixed-methods approach, the researchers first studied the parental and care team experience through interviews of Hypoplastic Left Heart Syndrome mothers and members of the inter-professional care team and then conducted an international survey of 690 Hypoplastic Left Heart Syndrome primary caregivers to validate the qualitative findings. Results: Parental and care team interviews revealed three main gaps in parental support, including lack of open communication, unrealistic parental expectations, and unclear inter-professional team roles. Survey results found that parents whose children were diagnosed with Hypoplastic Left Heart Syndrome after birth indicated significant dissatisfaction with the care team’s open communication and welcoming of feedback (p = 0.008). As parents progress through the stages of surgical intervention, they also indicate significant dissatisfaction with the care team’s anticipation of parental emotional needs and provision of coping resources (p = 0.003). Conclusions: Parental support interventions should focus on providing resources to help parents cope, helping the care team model open communication, and welcoming feedback on the parental experience. Practice implications: Interventions should be piloted with parents who are in the later stages of the surgical intervention timeline or whose children were diagnosed after birth as they are the populations who perceived the least support within this study.

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Certificates of Confidentiality (CoC) can be obtained from the National Institutes of Health (NIH) to protect researchers from forced disclosure of their participants’ personally identifiable information. We recently applied for an NIH CoC and it was approved. In this article, we describe an NIH CoC and why you might want one. Then we share our experiences in getting one, including one unexpected snag, and what we learned about CoCs that surprised us.