A challenge for healthcare system resilience after an earthquake: The crowdedness of a first-aid hospital by non-urgent patients.

After a violent earthquake, the supply of medical services may fall short of the rising demand, leading to overcrowding in hospitals, and, consequently, a collapse in the healthcare system. This paper takes the emergency care system in Taiwan as the research context, where first-aid hospitals are ranked to three levels, advanced, intermediate, and general, and, currently, emphasizes on a general emergency responsibility hospital. Having limited capacity and capability, a general emergency responsibility hospital treats minor and moderate injuries, from which the majority of earthquake-induced casualties suffer. The purpose of this study is to analyze the impact of this group of earthquake-induced non-urgent patients on the performance of a hospital. A patient flow model was built to represent patients' paths throughout emergency care. Based on the model, discrete event simulation was applied to simulate patients' trajectories and states of a hospital under four seismic scenarios, where patient visits are 1.4, 1.6, 1.9, and 2.3 times the normal number. A healthcare performance index, Crowdedness Index (CI), is proposed to measure crowdedness on a daily basis, which is defined as the ratio of the average waiting time for treatment to the recommended maximal waiting time. Results of simulations rendered the establishment of empirical equations, describing the relation between the maximum CIs and the patient growth ratios. In the most severe case in this study, the maximum CI exceeds 92 and it takes 10 days to recover from the quality drop. This highlights the problem a general emergency responsibility hospital may encounter if no emergency response measure is implemented. Findings are provided pertaining to the predication of a recovery curve and the alarming level of patient increase, which are supportive information for preparedness planning as well as response measure formulation to improve resilience.

Two types of oscillation in unequally compartmentalized granular gases.

Granular oscillation in an unequally two-compartmentalized system is investigated experimentally, yielding two time periods: τ(LS) represents the time period for particles moving from the large to the small compartment, and τ(SL) is the time needed for movement in a reverse direction. We construct the phase diagram for the unequal system, discovering that there exist two different granular oscillation states. In the GOI state, τ(LS)>τ(SL) is observed, and (τ(LS)-τ(SL)) increases as the difference between the two compartment widths is enlarged. In contrast, τ(LS)<τ(SL) is found in the GOII state, where the total number of particles is considerably lower than that in the GOI state. A flux model, accompanied by a proposed generalized granular temperature, is adopted to quantitatively calculate the observed time periods for both granular oscillation states. We find that the proposed temperature in each compartment is crucial in discriminating τ(LS) from τ(SL), and this is supported by the molecular dynamics analysis of mean kinetic energy of particles in a single compartment.

Intruder-induced change in condensation temperature of granular gases.

The process from a gaseous state to a clustering state for a compartmentalized monodisperse granular gas is accompanied by a drop in the granular temperature to a condensation point. We show experimentally that adding an intruder generally results in a decrease in the condensation point, and a heavier intruder makes this decrease more pronounced. However, once the Brazil nut effect (the intruder on the top of clustering grains) occurs, the condensation point will rise. Through the balance of particle fluxes and the hydrodynamic balance of driving forces, we analytically calculated the condensation point for the monodisperse gases and the intruder-fluid mixtures. The analytical results match the experimental data.

Fractal dimension analysis of periapical reactive bone in response to root canal treatment.

OBJECTIVE: Mathematical morphology and box counting were used to extract trabecular pattern and to evaluate changes of reactive bone following root canal treatment. STUDY DESIGN: Periapical radiographs were digitized and processed with mathematical morphology operations known as skeletonization. The trabecular patterns resulting from this skeletonization process were further analyzed with fractal dimension (FD) analysis using the box-counting method. Two groups of regions of interest (ROI) were selected from 19 subjects for the analysis. RESULTS: Seventeen patients in one group and 13 patients in the other showed decreased FD in the reactive bone region after clinically successful root canal treatment (RCT). Significant changes in FD were noted 6 months after RCT (P < .05). Kappa analysis indicated significant reproducibility between the 2 groups of ROIs. CONCLUSIONS: Mathematical morphology combined with box counting showed decrease of FD in reactive bone regions after clinically successful endodontic treatment.

Outcomes from out-of-hospital cardiac arrest in Metropolitan Taipei: does an advanced life support service make a difference?

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is of major medical and public health significance. It also serves as a good indicator in assessing the performance of local emergency medical services system (EMS). There have been arguments for and against the benefits of advanced life support (ALS) over basic life support with defibrillator (BLS-D) for treating OHCA. AIMS OF THE STUDY: The study was conducted to characterise the outcomes of cardiac arrest victims in an Asian metropolitan city; to evaluate the impacts of ALS versus BLS-D services; and to explore the possible patient and arrest factors that may be associated with the observed differences in the outcomes between the two pre-hospital care models. MATERIALS AND METHODS: Taipei is an Asian metropolitan city with an area of 272 km(2) and a population of 2.65 million. The fire-based BLS-D EMS system was in the process of phasing in ALS capability. While there were 40 BLS-D teams in the 12 city districts, two ALS teams were set up in the central part of the city. In this prospective study, all adult non-traumatic OHCA from September 2003 to August 2004 were included. Patient, arrest, care, and outcome variables for OHCA victims were collected from prehospital run sheets, automatic defibrillators, and emergency department and hospital records. RESULTS: Among 1423 OHCA included in the analysis, 1037 (73%) received BLS-D service, and 386 (27%) received ALS services. The initial shockable rhythms and early bystander CPR were strongly associated with better survival for victims of cardiac arrests. Compared to BLS-D, ALS patients had similar age, sex, witness status, the rate of bystander CPR, and response timeliness but more patients in asystole (84% versus 72%, p=0.005). Patients treated by ALS were more likely to result in significantly higher rates of return of spontaneous circulation (29% versus 21%; OR=1.51 (95% CI 1.15-2.00); p=0.002) and survival to emergency department/intensive care unit admission (23% versus 15%; OR=1.66 (95% CI 1.22-2.24); p=0.001), but there was no difference in the rate of survival to hospital discharge (7% versus 5%; OR=1.39 (95% CI 0.84-2.23); p=0.17). The outcome difference from ALS services was more pronounced among patients in asystole and without bystander CPR. CONCLUSIONS: In this metropolitan EMS in Asia, the implementation of ALS services improved the intermediate, but not the final outcomes. Communities with larger populations and lower incidence of initial shockable rhythms than the OPALS study should also prioritise their resources in setting up and optimising systems of basic life support and early defibrillations. Further studies are warranted to configure the optimal care model for combating cardiac arrest.

Digital imaging analysis with mathematical morphology and fractal dimension for evaluation of periapical lesions following endodontic treatment.

OBJECTIVE: To see if a method for digitizing trabecular pattern of bone could be used to quantitatively evaluate changes in bone pattern following endodontic treatment of teeth with periapical osteolytic lesions. STUDY DESIGN: Periapical radiographs were digitized and further processed with mathematical morphology operations known as skeletonization. The trabecular patterns resulting from this skeletonization process were further analyzed with fractal dimension analysis using box-counting. RESULTS: The periapical area in digitized radiographic images showed fractal behavior. Twenty-five of 27 patients showed increase of the fractal dimension after root canal treatment. Significant changes of the box-counting could be noted 3 months after root canal treatment (P < .05). CONCLUSIONS: Mathematical morphology operation and box-counting might be helpful in early detection of changes of periapical trabecular pattern after root canal treatment.

A pilot study applying digital radiography for estimating ratio of supported single-root surface area.

BACKGROUND: The prognosis of a tooth with periodontitis is affected by the amount of supporting bone. A key factor in retaining a tooth is the ratio of supported root surface. Currently, root surfaces cannot be accurately measured using conventional dental radiographs, which only measure the length of bone support on proximal surfaces. METHODS: Eight extracted, single-rooted teeth were 3-dimensionally digitized using a contact technique for true surface area measurements. Root length, projection area, and pixel values were then measured on digital radiographs. The accuracy of the ratio estimation of supported surface area from linear, area, and pixel values was calculated and compared. RESULTS: The mean error from linear estimation was 7.9%; the mean error from area estimation was 1.0%; and the mean error from pixel value estimation was 1.3%. One-way analysis of variance (ANOVA) showed significant differences in all estimations while Scheffé's analysis further revealed significant differences only in the linear estimation. CONCLUSIONS: A three-dimensional digitizing device could be used as a non-destructive method of measuring root surface area. The ratio of supported single-root surface area could be estimated with high accuracy from the projected area data acquired on the digital dental radiographs. The thickness data as reflected from the pixel values in the digital images did not improve the estimation accuracy. Estimations using only length data yielded significantly less accuracy. Digital dental x-ray images provide the potential for estimating the ratio of supported root surface efficiently.