Reducing adverse drug events: lessons from a breakthrough series collaborative

BACKGROUND: In January 1996, 38 hospitals and health care organizations (for a total of 40 hospitals) in the United States came together in an Institute for Healthcare Improvement (IHI; Boston) Breakthrough Series collaborative to reduce adverse drug events-injuries related to the use or nonuse of medications. METHODS: The participants were taught the Model for Improvement, a method for rapid-cycle change and evaluation, and were then coached on how to identify their own problem areas and develop changes in practice for rapid-cycle testing. These changes could be implementation of one or more known medication error prevention practices or new practices developed. RESULTS: During a 15-month period the 40 hospitals conducted a total of 739 tests of changes. Process changes accounted for 63% of the cycles; the remainder consisted of preliminary data gathering, consensus-building, or education cycles. Eight types of changes were implemented by seven or more hospitals, with a success rate of 70%. These changes included non-punitive reporting, ensuring documentation of allergy information, standardizing medication administration times, and implementing chemotherapy protocols. DISCUSSION: Success in making significant changes was associated with strong leadership, effective processes, and appropriate choice of intervention. Successful teams were able to define, clearly state, and relentlessly pursue their aims, and then chose practical interventions and moved early into changing a process. They did not spend months collecting data before beginning a change. Changes that were most successful were those that attempted to change processes, not people. Health care organizations committed to patient safety need not regard current performance limits as inevitable.     

Voluntary pacing and energy cost of off-road cycling and running

PURPOSE: The purposes of this study were (1) to compare self-chosen speed of off-road cyclists and runners on a hilly course, (2) to compare the energy expenditure of off-road cyclists and runners on the same terrain, and (3) to describe changes in energy expenditure over the course of the exercise period. METHODS: Runners and cyclists performed three laps on a 2.75 km gravel course in a single exercise bout. The course was divided into 13 segments differing in grade and length. Position on the course and heart rate were recorded every few seconds. Speed was computed for each course segment on each lap; energy expenditure was estimated using recorded heart rates and exercise-specific maximal oxygen uptake measurements made prior to participation in the study. RESULTS: There were significant relationships between grade and speed for both runners (r = 0.64) and cyclists (r = 0.44). The differences between cyclists and runners were greatest on downhill segments. Energy expenditure rates were not significantly different for runners (71.6% VO2 peak) and cyclists (68.5% VO2 peak). CONCLUSIONS: Off-road cycling and running are comparable in energy demands. Variation in skill levels may account for the increased variability in speed among cyclists on downhill terrain.     

Blood speed imaging with an intraluminal array

In applications in which Doppler processing is not possible, such as side-looking intravascular imaging systems, decorrelation methods can be used to estimate blood speed. Here, a method is presented measuring relative blood speed using an FIR filter bank to estimate temporal decorrelation rates. It can be implemented in a modern commercially available ultrasound imaging system with no additional hardware. Both simulations and experiments using an intraluminal scanner appropriate for coronary artery applications have tested the system. In this study, the FIR filter bank is contrasted with previous methods, and its utility is further demonstrated with real-time color flow images from a pig model.     

All-digital ring-wedge detector applied to image quality assessment

In the automatic assessment of image quality we obtained a high accuracy in the classification of image degradations in a manner that is widely independent of scene content. Using an all-digital ring-wedge detector system combined with neural-network software, we conducted several experiments in which the end goal is to classify images according to numerical quality scales. Experiments are presented to stress the importance of both local and global image quality assessment. Two databases of degraded images were prepared. One uses five levels of Gaussian blur to simulate depth of field. The other was prepared with lossy compression and recovery with artifacts generated by a JPEG (Joint Photographic Experts Group) compression algorithm. In quantitative terms our best sorting of Gaussian blur without knowledge of the original scene was to an accuracy of 96%. For degradation using JPEG we obtained an accuracy of 95% without knowledge of the original and 98% when the original scene is available as a reference.     

Closed-loop stimulation of hypoglossal nerve in a dog model of upper airway obstruction

Electrical stimulation of upper airway (UAW) muscles has been under investigation as a treatment method for obstructive sleep apnea (OSA). Particular attention has been given to the electrical activation of the genioglossal muscle, either directly or via the stimulation of the hypoglossal nerve (HG), since the genioglossus is the main tongue protrusor muscle. Regardless of the stimulation site or method, an implantable electrical stimulation device for OSA patients will require a reliable method for detection of obstructive breaths to apply the stimulation when needed. In this paper, we test the hypothesis that the activity of the HG nerve can be used as a feedback signal for closed-loop stimulation of the HG nerve in an animal model of UAW obstruction where a force is applied on the submental region to physically narrow the airways. As an advantage, the method uses a single electrode for both recording and stimulation of the HG nerve. Simple linear filtering techniques were found to be adequate for producing the trigger signal for the electrical stimulation from the HG recordings. Esophageal pressure, which was used to estimate the size of the UAW passage, returned to the preloading values during closed-loop stimulation of the HG nerve. The data demonstrate the feasibility of the closed-loop stimulation of the HG nerve using its activity as the feedback signal.     

Cryosurgical monitoring using bioimpedance measurements--a feasibility study for electrical impedance tomography

The effectiveness of cryosurgery in treating tumors is highly dependent on knowledge of freezing extent, and therefore relies heavily on real-time imaging techniques for monitoring. Electrical impedance tomography (EIT), which utilizes tissue impedance variation to construct an image, is very well suited to cryosurgery since frozen tissue impedance is much higher than that of unfrozen tissue. In this study, we explore cryosurgical monitoring as a previously uninvestigated application for EIT. The feasibility of bio-impedance measurements to detect ice front propagation is demonstrated by freezing planar tissue samples one-dimensionally while measuring impedance along a linear array. The experimental results compare favorably to a simple finite element model designed to provide an electrical field visualization tool.     

Glycogen concentrations in bovine longissimus dorsi muscle

The aim of this study was to assess the effect of location within bovine longissimus dorsi (thoracis et lumborum) muscle (LTL) when determining glycogen concentration. Six locations in Angus heifers were sampled post mortem (EXP-1) and eight locations in live Charolais crossbred steers were biopsied (EXP-2). In EXP-1, there was more glycogen in the animals' left LTL (64.1±1.6 mmol/kg) versus the right LTL (57.0±1.6 mmol/kg) (P<0.05). Locations along the cranial-caudal axis within LTL did not differ in glycogen concentration. Results for EXP-2 did not confirm the sidedness effect. Instead, it showed that glycogen concentration was lower at the cranial sampling locations near the 10th rib (89±2.5 mmol/kg) than at the middle (97±2.0 mmol/kg) or caudal locations (96±1.9 mmol/kg) (P<0.005). Taking lactate accumulation into account (glycolytic potential) rendered those differences insignificant. Nevertheless, the tendency remained clear. The potential for dilution of glycogen by intramuscular fat deposits is discussed. The results indicate that one needs to be cautious in performing repeated sampling on bovine LTL.     

Characterization of polyphosphates by electrospray mass spectrometry

Electrospray ionization mass spectrometry (ESI-MS) was applied for the characterization of inorganic polyphosphates [orthophosphate, pyrophosphate, tripolyphosphate, trimetaphosphate, and tetrapolyphosphatel. The high selectivity of ESI-MS allows the detection of different polyphosphate species without preseparation by ion chromatography or capillary electrophoresis. Furthermore, ESI-MS does not require the incorporation of UV-absorbing chromophores into the analytical method for the detection of phosphates, unlike conventional UV-chromatographic methods. Limits of detection by ESI-MS were estimated to range from approximately 1 to 10 ng/mL. The quantification of polyphosphate samples as single-component and multicomponent mixtures was investigated. Linear signal response for single-component samples ranged from the limit of detection to approximately 10 microg/mL Quantification of polyphosphate in streamwater is demonstrated using the standard addition method. The effect of multi-polyphosphate components and salts on signal response was also studied. For concentrations less than 2.0 microg/mL, signal response from a tetrapolyphosphate sample was comparable to those obtained from tetrapolyphosphate-tripolyphosphate mixtures. Signal response obtained from tetrapolyphosphate in the presence of tripolyphosphate or NH4NO3 at higher concentrations (approximately 50 microg/mL and 35 microg/mL, respectively) was significantly lower relative to single-component standards (approximately 40%-70%).     

Ultrasound measurement of brachial flow-mediated vasodilator response

Brachial artery flow-mediated vasodilation is increasingly used as a measure of endothelial function. High resolution ultrasound provides a noninvasive method to observe this flow-mediated vasodilation by monitoring the diameter of the artery over time following a transient flow stimulus. Since hundreds of ultrasound images are required to continuously monitor brachial diameter for the 2-3 min during which the vasodilator response occurs, an automated diameter estimation is desirable. However, vascular ultrasound images suffer from structural noise caused by the constructive and destructive interference of the backscattered signals, and the true boundaries of interest that define the diameter are frequently obscured by the multiple-layer structure of the vessel wall. These problems make automated diameter estimation strategies based on the detection of the vessel wall boundary difficult. We obtain a robust automated measurement of the vasodilator response by automatically locating the artery using a variable window method, which gives both the lumen center and width. The vessel wall boundary is detected by a global constraint deformable model, which is insensitive to the structural noise in the boundary area. The ambiguity between the desired boundary and other undesired boundaries is resolved by a spatiotemporal strategy. Our method provides excellent reproducibility both for interreader and intrareader analyzes of percent change in diameter, and has been successfully used in analyzing over 4000 brachial flow-mediated vasodilation scans from several medical centers in the United States.     

Determination of end groups of synthetic polymers by matrix-assisted laser desorption/ionization: high-energy collision-induced dissociation

Matrix-assisted laser desorption/ionization has been combined with high-energy collision-induced dissociation for the analysis of poly(ethylene glycols) with butanoyl, benzoyl and acetyl end groups, using novel technology comprising a magnetic-sector mass spectrometer and ion buncher with an in-line quadratic-field ion mirror. High-energy (>8 keV) collision-induced dissociation facilitated unambiguous end-group determination of these polymers, providing masses of end groups and structural information. The high-energy collision-induced dissociation also provided information regarding repeat units.