Evaluating the impact of external forces on peripheral intravenous catheter movement using ultrasound: A randomized pilot study

BACKGROUND

A major contributor to peripheral intravenous catheter (PIVC) failure may be related to PIVC movement within the vein which is associated with vein wall damage. The magnitude of PIVC movement against the vein wall has not previously been quantified. This study aimed to examine PIVC movement within the vein when minor forces were applied to the PIVC.

METHODS

This was a prospective, pilot trial including healthy volunteers in an outpatient research laboratory. The primary objective was to examine the in movement (millimeters) of the PIVC using ultrasound with external pull forces (4, 5, and 6 lbs; 1.8, 2.3, and 2.7 kg, respectively) applied to the PIVC in random order.

RESULTS

Participants (N = 11) were aged 40.36 ± 16.10 years with 54.55% being Male. Mean ± SD PIVC movement for 4, 5, and 6 lbs of force was 4.65 ± 1.88, 3.88 ± 2.28, and 5.25 ± 2.06 mm, respectively. There was substantial PIVC movement when a force was applied to the PIVC, but no statistically significant difference between 4, 5, and 6 lb forces (p > 0.05).

CONCLUSION

When external pull forces were applied to the PIVC, substantial PIVC movement within the vein occurred in a healthy population. Strategies that reduce PIVC movement and/or remove or limit external pull forces from the PIVC are needed. Future studies on hospitalized patients are warranted to quantify vein wall injury and PIVC failure due to PIVC movement from various pull forces.

Application of dGNSS in Alpine Ski Racing: Basis for Evaluating Physical Demands and Safety

External forces, such as ground reaction force or air drag acting on athletes' bodies in sports, determine the sport-specific demands on athletes' physical fitness. In order to establish appropriate physical conditioning regimes, which adequately prepare athletes for the loads and physical demands occurring in their sports and help reduce the risk of injury, sport-and/or discipline-specific knowledge of the external forces is needed. However, due to methodological shortcomings in biomechanical research, data comprehensively describing the external forces that occur in alpine super-G (SG) and downhill (DH) are so far lacking. Therefore, this study applied new and accurate wearable sensor-based technology to determine the external forces acting on skiers during World Cup (WC) alpine skiing competitions in the disciplines of SG and DH and to compare these with those occurring in giant slalom (GS), for which previous research knowledge exists. External forces were determined using WC forerunners carrying a differential global navigation satellite system (dGNSS). Combining the dGNSS data with a digital terrain model of the snow surface and an air drag model, the magnitudes of ground reaction forces were computed. It was found that the applied methodology may not only be used to track physical demands and loads on athletes, but also to simultaneously investigate safety aspects, such as the effectiveness of speed control through increased air drag and ski-snow friction forces in the respective disciplines. Therefore, the component of the ground reaction force in the direction of travel (ski-snow friction) and air drag force were computed. This study showed that (1) the validity of high-end dGNSS systems allows meaningful investigations such as characterization of physical demands and effectiveness of safety measures in highly dynamic sports; (2) physical demands were substantially different between GS, SG, and DH; and (3) safety-related reduction of skiing speed might be most effectively achieved by increasing the ski-snow friction force in GS and SG. For DH an increase in the ski-snow friction force might be equally as effective as an increase in air drag force.

The Influence of External Forces on Wrist Proprioception

Proprioception combines information from cutaneous, joint, tendon, and muscle receptors for maintaining a reliable internal body image. However, it is still a matter of debate, in both neurophysiology and psychology, to what extent such body image is modified or distorted by a changing haptic environment. In particular, what is worth investigating is the contribution of external forces on our perception of body and joint configuration. The proprioceptive acuity of fifteen young participants was tested with a Joint Position Matching (JPM) task, performed with the dominant wrist under five different external forces, in order to understand to what extent they affect proprioceptive acuity. Results show that accuracy and precision in target matching do not change in a significant manner as a function of the loading condition, suggesting that the multi-sensory integration process is indeed capable of discriminating different sub-modalities of proprioception, namely the joint position sense and the sense of force. Furthermore, results indicate a preference for target undershooting when movements are performed in a viscous or high resistive force field, rather than passive or null fields in which subjects did not show any predominance for under/over estimation of their position.

Subnanometer Two-Dimensional Graphene Oxide Channels for Ultrafast Gas Sieving

Two-dimensional (2D) materials with atomic thickness and extraordinary physicochemical properties exhibit unique mass transport behaviors, enabling them as emerging nanobuilding blocks for separation membranes. Engineering 2D materials into membrane with subnanometer apertures for precise molecular sieving remains a great challenge. Here, we report rational-designing external forces to precisely manipulate nanoarchitecture of graphene oxide (GO)-assembled 2D channels with interlayer height of ∼0.4 nm for fast transporting and selective sieving gases. The external forces are synergistic to direct the GO nanosheets stacking so as to realize delicate size-tailoring of in-plane slit-like pores and plane-to-plane interlayer-galleries. The 2D channels endow GO membrane with excellent molecular-sieving characteristics that offer 2-3 orders of magnitude higher H2 permeability and 3-fold enhancement in H2/CO2 selectivity compared with commercial membranes. Formation mechanism of 2D channels is proposed on the basis of the driving forces, nanostructures, and transport behaviors.