Implementing a system for the real-time risk assessment of patients considered for intensive care

BACKGROUND

Delay in identifying deterioration in hospitalised patients is associated with delayed admission to an intensive care unit (ICU) and poor outcomes. For the HAVEN project (HICF ref.: HICF-R9-524), we have developed a mathematical model that identifies deterioration in hospitalised patients in real time and facilitates the intervention of an ICU outreach team. This paper describes the system that has been designed to implement the model. We have used innovative technologies such as Portable Format for Analytics (PFA) and Open Services Gateway initiative (OSGi) to define the predictive statistical model and implement the system respectively for greater configurability, reliability, and availability.

RESULTS

The HAVEN system has been deployed as part of a research project in the Oxford University Hospitals NHS Foundation Trust. The system has so far processed > 164,000 vital signs observations and > 68,000 laboratory results for > 12,500 patients and the algorithm generated score is being evaluated to review patients who are under consideration for transfer to ICU. No clinical decisions are being made based on output from the system. The HAVEN score has been computed using a PFA model for all these patients. The intent is that this score will be displayed on a graphical user interface for clinician review and response.

CONCLUSIONS

The system uses a configurable PFA model to compute the HAVEN score which makes the system easily upgradable in terms of enhancing systems' predictive capability. Further system enhancements are planned to handle new data sources and additional management screens.

Measuring the readership of a health-related Website

A national database of telemedicine was set up with the sponsorship of the British government to provide a source of information to anyone researching the field or proposing a telemedicine project. To monitor the readership of the database we subscribed to a free Internet service called Extreme Tracking. Since the Website was launched there have been over 9000 visits from over 5000 different Internet addresses. The peak was in the week after launch, when it had 400 visitors in four days. Subsequently, the number of visits tailed off slightly, but nine months later the database was still attracting about 800 visits per month. The majority of visits were via links from other Websites. Of the 288 different Websites identified, the one operated by the UK National Health Service (NHS) Information Authority generated the most visits, suggesting that many readers were from within the NHS. The second most common form of referral was from search engines. Most visits were on weekdays and during normal UK working hours. Taken together with the fact that the Internet domain that generated most visits was the ‘.uk’ one, we concluded that most readers were based in the UK and accessed the site as part of their jobs rather than as a spare-time activity. This is encouraging for the take-up of telemedicine in the UK.

Comparison of the National Early Warning Score in non-elective medical and surgical patients

BACKGROUND

The National Early Warning Score (NEWS) is used to identify deteriorating patients in hospital. NEWS is a better discriminator of outcomes than other early warning scores in acute medical admissions, but it has not been evaluated in a surgical population. The study aims were to evaluate the ability of NEWS to discriminate cardiac arrest, death and unanticipated ICU admission in patients admitted to surgical specialties, and to compare the performance of NEWS in admissions to medical and surgical specialties.

METHODS

Hospitalwide data over 31 months, from adult inpatients who stayed at least one night or died on the day of admission, were analysed. The data were categorized as elective or non-elective surgical or medical admissions. The ability of NEWS to discriminate the outcomes above in these different groups was assessed using the area under the receiver operating characteristic curve (AUROC).

RESULTS

There were too few outcomes to permit meaningful comparison of elective admissions, so the analysis was constrained to comparison of non-elective admissions. NEWS performed equally well, or better, for surgical as for medical patients. For death within 24 h the AUROC for surgical admissions was 0·914 (95 per cent c.i. 0·907 to 0·922), compared with 0·902 (0·898 to 0·905) for medical admissions. For the combined outcome of any of death, cardiac arrest or unanticipated ICU admission, the AUROC was 0·874 (0·868 to 0·880) for surgical admissions and 0·874 (0·871 to 0·877) for medical admissions.

CONCLUSION

NEWS discriminated deterioration in non-elective surgical patients at least as well as in non-elective medical patients.

Decision-tree early warning score (DTEWS) validates the design of the National Early Warning Score (NEWS)

AIM OF STUDY

To compare the performance of a human-generated, trial and error-optimised early warning score (EWS), i.e., National Early Warning Score (NEWS), with one generated entirely algorithmically using Decision Tree (DT) analysis.

MATERIALS AND METHODS

We used DT analysis to construct a decision-tree EWS (DTEWS) from a database of 198,755 vital signs observation sets collected from 35,585 consecutive, completed acute medical admissions. We evaluated the ability of DTEWS to discriminate patients at risk of cardiac arrest, unanticipated intensive care unit admission or death, each within 24h of a given vital signs observation. We compared the performance of DTEWS and NEWS using the area under the receiver-operating characteristic (AUROC) curve.

RESULTS

The structures of DTEWS and NEWS were very similar. The AUROC (95% CI) for DTEWS for cardiac arrest, unanticipated ICU admission, death, and any of the outcomes, all within 24h, were 0.708 (0.669-0.747), 0.862 (0.852-0.872), 0.899 (0.892-0.907), and 0.877 (0.870-0.883), respectively. Values for NEWS were 0.722 (0.685-0.759) [cardiac arrest], 0.857 (0.847-0.868) [unanticipated ICU admission}, 0.894 (0.887-0.902) [death], and 0.873 (0.866-0.879) [any outcome].

CONCLUSIONS

The decision-tree technique independently validates the composition and weightings of NEWS. The DT approach quickly provided an almost identical EWS to NEWS, although one that admittedly would benefit from fine-tuning using clinical knowledge. We believe that DT analysis could be used to quickly develop candidate models for disease-specific EWSs, which may be required in future.

STAT-HI: A socio-technical assessment tool for health informatics implementations

This paper proposes a socio-technical assessment tool (STAT-HI) for health informatics implementations. We explore why even projects allegedly using sound methodologies repeatedly fail to give adequate attention to socio-technical issues, and we present an initial draft of a structured assessment tool for health informatics implementation that encapsulates socio-technical good practice. Further work is proposed to enrich and validate the proposed instrument. This proposal was presented for discussion at a meeting of the UK Faculty of Health Informatics in December 2009.

Theory of deep minima in (e,2e) measurements of triply differential cross sections

Deep minima in He(e,2e)He+ triply differential cross sections are traced to vortices in atomic wave functions. Such vortices have been predicted earlier, but the present calculations show that they have also been observed experimentally, although not recognized as vortices. Their observation in (e,2e) measurements shows that vortices play an important role in electron correlations related to the transfer of angular momentum between incident and ejected electrons. The vortices significantly extend the list of known features that summarize the general picture of electron correlations in impact ionization.

Measuring clinical performance using routinely collected clinical data

Following the well-publicized problems with paediatric cardiac surgery at the Bristol Royal Infirmary, there is wide public interest in measures of hospital performance. The Kennedy report on the BRI events suggested that such measures should be meaningful to the public, case-mix-adjusted, and based on data collected as part of routine clinical care. We have found that it is possible to predict in-hospital mortality (a measure readily understood by the public) using simple routine data-age, mode of admission, sex, and routine blood test results. The clinical data items can be obtained at a single venesection, are commonly collected in the routine care of patients, are already stored on hospital core IT systems, and so place no extra burden on the clinical staff providing care. Such risk models could provide a metric for use in evidence-based clinical performance management. National application is logistically feasible.

Developing a theoretical model of clinician information usage propensity

Based on qualitative research, we developed the theoretical construct "clinician information usage propensity" as a hypothetical indicator of attitudes and behaviour towards clinical information and systems. We devised a survey to validate the construct and had 146 responses. Principal components analysis extracted four factors accounting for 47.2% of the variance: beliefs about clinical judgement, beliefs about information quality, cultural resistance and cognitive approach. The components were reasonably consistent with the model but two factors (beliefs about information quality, cognitive approach) had low reliability (alpha<0.6). Cultural resistance was the main factor and correlated with gender, grade and age group. Female clinicians showed significantly higher cultural resistance and preference for narrative; hospital doctors generally had higher cultural resistance than general practitioners. As only 47.2% of the variance was explained, further work is needed to refine the instrument to remove redundancy, improve sensitivity on the identified components and allow the construct to be explored as a form of technology adoption model. We posit that beliefs about clinical judgement merit further attention in medical informatics research.

Double-electron transfer in H(-) + H(+) collisions

Absolute cross sections for double-electron transfer in H(-) + H(+) collisions have been measured for center-of-mass energies from 0.5 to 12 keV. Clear oscillations in the cross section are observed shedding new light on earlier measurements. Calculations based on a diabatic approach are shown to reproduce this behavior, but require a larger diabatic ion-pair splitting than previously assumed.

(e,3e) on helium at low impact energy: the strongly correlated three-electron continuum

Double ionization of the helium atom by slow electron impact (E(0)=106 eV) is studied in a kinematically complete experiment. Because of a low excess energy E(exc)=27 eV above the double ionization threshold, a strongly correlated three-electron continuum is realized. This is demonstrated by measuring and calculating the fully differential cross sections for equal energy sharing of the final-state electrons. While the electron emission is dominated by a strong Coulomb repulsion, also signatures of more complex dynamics of the full four-body system are identified.

Theory of the absorption and circular dichroism spectra of helical molecular aggregates

A theory of the electronic circular dichroism (CD) and optical rotatory dispersion (ORD) of infinite aggregates exhibiting cylindrical symmetry is presented in which, to the authors' knowledge, for the first time vibrational structure is included explicitly. It is shown that, with the coherent exciton scattering approximation in the Green function approach, the detailed vibrational structure of the aggregate absorption. CD and ORD bands can be calculated from a knowledge of the electronic coupling and the monomer absorption line shape alone. Detailed model calculations for a single helix are made and the results are used to expose the origin of different spectral features. A good reproduction of experimental J-aggregate spectra is obtained, using the same electronic interaction to fit both absorption and CD spectral line shapes. The theory allows some prediction of aggregate geometry to be made, but it is shown that an unambiguous geometrical assignment can only be made where experimental spectra for light of different propagation directions with respect to the cylinder axis are available.

Absorption spectra of quantum aggregates interacting via long-range forces

We present a simple formula by which the shape of the absorption spectrum of an aggregate of quantum "monomers" (cold atoms, molecules, quantum dots, nanoparticles, etc.) interacting via dipole-dipole forces can be calculated from the averaged spectrum of the quantum monomer itself. Spectral broadening, due to a wide variety of causes, is included explicitly so that the formula is applicable not only to the idealization of a discrete spectrum but also to the practical situation of a continuously broadened spectrum. In simple cases, analytic results are obtained showing the strong dependence of the aggregate spectrum on the precise nature of the broadening of the quantum monomer spectrum. The formula is compared with results of exact diagonalization of model aggregate Hamiltonians and with experiment.

The ISABEL user survey

ISABEL is a web-based clinical decision-support system for use by health care professionals. The Web site has been developed by the ISABEL Medical Charity. The system has come to the attention of the Department of Health, which is examining its potential effectiveness in the wider clinical context and exploring options for promoting its wider use in the NHS. The objectives of the work reported here were to review the existing use of ISABEL and to identify impediments to its development. A questionnaire was sent by e-mail to selected users of the system. Based on an analysis of the results (n=518), we found ISABEL to be a useful tool with many users. We believe that there is evidence of its success sufficient to support its continued availability and development. However, the largest hurdles to its increased use are systemic ones within the NHS and the way services are delivered.

Vibronic energies and spectra of molecular dimers

We consider three distinct methods of calculating the vibronic levels and absorption spectra of molecular dimers coupled by dipole-dipole interactions. The first method is direct diagonalization of the vibronic Hamiltonian in a basis of monomer eigenstates. The second method is to use creation and annihilation operators leading in harmonic approximation to the Jaynes-Cummings Hamiltonian. The adiabatic approximation to this problem provides insight into spectral behavior in the weak and strong coupling limits. The third method, which serves as a check on the accuracy of the previous methods, is a numerically exact solution of the time-dependent Schrodinger equation. Using these methods, dimer spectra are calculated for three separate dye molecules and show good agreement with measured spectra.

Shape-amplitude representation of N-particle photofragmentation processes

The general form of the multiparticle photofragmentation matrix element in dipole approximation is derived. Using two noncolinear momentum vectors to create a coordinate system enables the extraction of shape amplitudes depending only on lengths and mutual angles of the momentum vectors, i.e., on body fixed quantities, defining the fragmentation configuration. This is in contrast to previous parametrizations and, in particular, allows selection rules to be derived in a simpler and more transparent way.

Elimination of body-frame singularities in the separation of three collective angles in quantum N-body problems

The appearance of body-frame singularities in gauge potentials when three collective angles are separated by means of Wigner D-functions is a fundamental difficulty in the quantum N-body problem. We show that the use of the overcomplete basis of minimal multipolar harmonics allows these singularities to be avoided at the expense of increasing the dimension of the resulting system of coupled equations describing the internal motion of the system.

Measuring the readership of a health-related Website

A national database of telemedicine was set up with the sponsorship of the British government to provide a source of information to anyone researching the field or proposing a telemedicine project. To monitor the readership of the database we subscribed to a free Internet service called Extreme Tracking. Since the Website was launched there have been over 9000 visits from over 5000 different Internet addresses. The peak was in the week after launch, when it had 400 visitors in four days. Subsequently, the number of visits tailed off slightly, but nine months later the database was still attracting about 800 visits per month. The majority of visits were via links from other Websites. Of the 288 different Websites identified, the one operated by the UK National Health Service (NHS) Information Authority generated the most visits, suggesting that many readers were from within the NHS. The second most common form of referral was from search engines. Most visits were on weekdays and during normal UK working hours. Taken together with the fact that the Internet domain that generated most visits was the '.uk' one, we concluded that most readers were based in the UK and accessed the site as part of their jobs rather than as a spare-time activity. This is encouraging for the take-up of telemedicine in the UK.

Selection rules and isotope effects in the full fragmentation of the hydrogen molecule

Selection rules predicting zeros in cross sections for full fragmentation of the hydrogen molecule into specific momentum configurations are presented. Isotope effects are predicted to arise from these selection rules and from the correlated motion of nuclei and electrons in the final state.

Internet developments and their significance for healthcare

This paper reviews some recent developments in the technology of the Internet, and shows how they may affect the way in which healthcare is provided. Starting with a brief technical history of the Internet, the paper discusses some of the technical developments that have taken place or been proposed in recent years, and speculates on the realities of their adoption within the next five years. The paper also discusses trends in public accessibility to the Internet and the development of Internet services. Finally, the impact of the technological developments on the way in which new healthcare services may be provided is discussed. Our conclusions are that the growth rate in Internet access and the improvements in performance resulting from the new technologies will make the Internet the focus of many new healthcare developments, in particular in the areas of telemedicine and in communication between patient and healthcare professionals. Increasingly, the Internet will be used to convey more 'real-time' information.