Adding value to daily chest X-rays in the ICU through education, restricted daily orders and indication-based prompting.

BACKGROUND: Chest X-rays (CXRs) are traditionally obtained daily in all patients on invasive mechanical ventilation (IMV) in the intensive care unit (ICU). We sought to reduce overutilisation of CXRs obtained in the ICU, using a multifaceted intervention to eliminate automated daily studies. METHODS: We first educated ICU staff about the low diagnostic yield of automated daily CXRs, then removed the 'daily' option from the electronic health records-based ordering system, and added a query (CXR indicated or not indicated) to the ICU daily rounding checklist to prompt a CXR order when clinically warranted. We built a report from billing codes, focusing on all CXRs obtained on IMV census days in the medical (MICU) and surgical (SICU) ICUs, excluding the day of admission and days that a procedure warranting CXR was performed. This generated the number of CXRs obtained every 1000 'included' ventilator days (IVDs), the latter defined as not having an 'absolute' clinical indication for CXR. RESULTS: The average monthly number of CXRs on an IVD decreased from 919±90 (95% CI 877 to 963) to 330±87 (95% CI 295 to 354) per 1000 IVDs in the MICU, and from 995±69 (95% CI 947 to 1055) to 649±133 (95% CI 593 to 697) in the SICU. This yielded an estimated 1830 to 2066 CXRs avoided over 2 years and an estimated annual savings of $191 600 to $224 200. There was no increase in reported adverse events. CONCLUSION: ICUs can safely transition to a higher value strategy of indication-based chest imaging by educating staff, eliminating the 'daily' order option and adding a simplified prompt to avoid missing clinically indicated CXRs.

Effects of electrode size and spacing on the resolution of intracardiac electrograms.

BACKGROUND: Electrogram fractionation can result when multiple groups of cardiac cells are excited asynchronously within the recording region of a mapping electrode. The spatial resolution of an electrode thus plays an important role in mapping complex rhythms. METHODS: We used a computational model, validated against experimental measurements in vitro, to determine how spatial resolution is affected by electrode diameter, electrode length, interelectrode distance (in the case of bipolar recordings), and height of the electrode above a dipole current source. RESULTS: We found that increases in all these quantities caused progressive degradation in two independent measures of spatial resolution, with the strongest effect being due to changes in height above the tissue. CONCLUSION: Our calculations suggest that if electrodes could be constructed to have negligible dimensions compared with those in use today, we would increase resolution by about one order of magnitude at most.

A Removable Precision Device for In-Vivo Mechanical Compression of Rat Tail Intervertebral Discs.

The rat tail intervertebral disc has emerged as an important model to examine the mechanisms for mechanically induced degeneration and remodeling. Previous methods used to apply high precision axial compressive loading to a rat tail intervertebral disc in vivo either required anesthesia, or the permanent mounting of a loading device to the animal, and were not well described in the literature. Therefore, a new device to apply compressive loading to the rat tail intervertebral disc was developed and validated. The rat tail compressive loading system utilized a pneumatically driven device weighing 18 g, and was capable of delivering a 12.6 N sinusoidal or square waveform at frequencies up to 1.0 Hz. The system improved on previous methods in its modular construction, relative ease of fabrication, compatibility with existing tail model technology and overall cost effectiveness. The removable system eliminated the need for anesthesia and through a modular, cost effective, design allowed for the simultaneous loading of multiple animals. This system expanded the ability to accurately, ethically, and efficiently apply dynamic compressive loads to the rat tail intervertebral disc for extended periods of time in order to address questions related to disc mechanobiology.