Kelly, Kevin L.

Slow, deep breathing (SDB) is thought to lead to reductions in blood pressure by decreasing vascular‐sympathetic coupling. Venous Occlusion Plethysmography (VOP) is used to assess forearm blood flow (FBF) (ml/min/100 dl tissue). We used this technique to determine the vasodilatory effect of device‐guided (DG) vs self‐paced (SP) slow, deep breathing. We hypothesized that SP would lead to a larger vasodilation response than DG due to a more profound reduction in vascular‐sympathetic coupling, and that this would be correlated with psychological evaluations. Young, healthy male subjects (Mean age: 20 yr; DG: n=10; SP: n=11) rested supine for 20 minutes (baseline), followed by 20 minutes of SP or DG slow, deep breathing, then completed 20 minutes of endogenous breathing (recovery). At baseline, there was no difference in breathing rate between SP and DG (14.36±1.03 vs 15.39±1.29 breaths per minute, p=0.27) and respiratory rate was reduced to 8.36±0.74 breaths per minute (BPM) in the SP group (p<0.01 compared to baseline) and to 6.37±0.10 BPM in the DG group (p<0.01 compared to baseline). Respiratory rates between the two groups differed significantly during SDB (p<0.01 between groups). There was a significant increase in SP FBF compared to baseline at the end of the 20 minute intervention (p<0.05),while the DG group saw no significant increases. In DG, there was a strong negative correlation with the cognitive interference scores to VOP responsiveness (−0.77; R2=0.591), as well as between the cognitive failure score and VOP responsiveness (−0.61; R2=0.3693). In contrast, the SP groups had positive correlations when comparing VOP responsiveness to cognitive interference (0.1; R2=0.093) or cognitive failure (0.30; R2=0.011). For subjects in either breathing group, those who had an increase in FBF in response to SDB also had reductions in STAI anxiety score after the intervention whereas those with a decrease in FBF to SDB had an increase in anxiety score during the slow breathing (p=0.04). Overall, male subjects have a variable vasodilator responses to two types of SDB practices related to underlying psychological metrics. Our data underscores the importance of psychological metrics in physiological outcomes related to SDB practices.

Physiology undergraduate degree programs operate in isolation relative to other biological science programs, with little to no understanding of how other institutions structure their course requirements and other degree requirements. The purpose of this report is to preliminarily describe the collective curriculum of physiology programs represented at the Physiology Majors Interest Group (P-MIG) annual meetings from 2018 to 2019. A short preconference survey was sent to attendees that inquired about degree requirements of their respective physiology programs. The requirement for Physiology I (69.2%) with laboratory (66.7%) and Anatomy I (57.1%) with laboratory (42.9%), or combined Anatomy and Physiology I (16.7%) and laboratory (18.2%), were common requirements, but many programs did not require Physiology II (27.3%) or Anatomy II (11.1%). There was nearly consensus on required prerequisites such as Biology (2 semesters with laboratories, 85.7%), Chemistry (2 semesters with laboratory, 88.9%), Physics (2 semesters with laboratory, 75%), Calculus I (61.1%), and Statistics (Biostatistics 42.9%; General Statistics 13.3%). There was less agreement among programs in regards to Calculus II (20.0%), Organic Chemistry (2 semesters, 55.6%), and Biochemistry I (47%), which may be reflective of individual department focus. There was considerable heterogeneity among physiology program course requirements for disciplinary core courses and upper division electives. This report is meant to generate discussion on physiology program curricula in efforts to improve physiology education for majors and assist P-MIG in determining minimal points of consensus as they write the first set of national curricular guidelines for degree programs.

Medical compression garments are used to treat lymphatic disorders or conditions of poor venous return (e.g. orthostatic intolerance). Conventional compression garments, namely elastic compression sleeves and inflatable compression systems, may aid in relief of these conditions but are also limited in usability. Fixed levels of compression in elastic materials may induce challenges in donning/doffing, complicating patient compliance [1]. Compression levels in inflatable systems are customizable, but these garments are also bulky and require a tethered inflation source [2]. We are interested in developing easy-to-don/-doff compression garments using shape memory alloy (SMA) coil actuators that contract with heat from an applied current which can be wrapped around the body to apply compressive forces. More specifically, we use a spring coil formation as described by Holschuh et al. [3]. Further developed in the Wearable Technology Lab at the University of Minnesota, our current SMA compression garment (SMA-CG) design improves upon the work of Duvall et al. [4] presented in previous year’s (2017) Design of Medical Devices Conference, representing a year’s evolution in active compression garment design that integrate actuators made with SMA.

Current compression garments are often made from a spandex-type elastic material with static levels of compression and can become uncomfortable and difficult to don/doff [1]. This limits their usability, especially for unhealthy or aging populations. The only current alternative to elastic compression stockings are inflatable compression sleeves that are controllable, but highly immobile and must be tethered to an inflation source [2]. Neither design offers a solution that is simultaneously low profile, mobile, and controllable. Here we present the design and development of compression garments with embedded shape-changing materials that can produce controllable compression without the need for a bulky inflation system. This active materials approach enables dynamic control over the degree, timing and location of compression, and allows for graded, synchronized, pulsed, and peristaltic compression patterns, which provide the medical benefit of moving fluid in the body [2]. Such a design combines the best features of both elastic and inflatable compression garments: a slim, low-profile form factor that is easy to don/doff and provides dynamic control. Shape memory alloy (SMA) coil actuators, as described by Holschuh et al., [3] have the ability to apply compressive forces to the body when paired with passive textiles and wrapped circumferentially around the body. These actuators are engineered to contract when heated, creating controllable forces and displacements that are modulated through an applied current. SMA compression garments (SMA-CG) have important applications, from consumer uses to clinical interventions, including: augmenting venous return for conditions of orthostatic intolerance (e.g., postural orthostatic tachycardia syndrome (POTS)); cardiac rehabilitation in heart failure patients; lymphedema venous insufficiency; reducing deep vein thrombosis (DVT) risk; sports performance; and countermeasures for flight or space flight. While the potential uses for this technology are broad, the basic design is similar across many conditions. Key research areas include: 1) identifying and addressing design considerations relevant to prototype development of SMA-CG; 2) determining the compression thresholds needed to dynamically oppose orthostatic changes; and 3) evaluating the effectiveness of the prototypes for augmented venous return by synchronizing compression during cardiac diastole. Here, we focus on the first question: design of SMA-CG prototypes.