The problem of hospital patients’ delayed discharge or ‘bed blocking’ has long been a challenge f... more The problem of hospital patients’ delayed discharge or ‘bed blocking’ has long been a challenge for healthcare managers and policymakers. It negatively affects the hospital performance metrics and has other severe consequences for the healthcare system, such as affecting patients’ health. In our previous work, we proposed the phase-type survival tree (PHTST)-based analysis to cluster patients into clinically meaningful patient groups and an extension of this approach to examine the relationship between the length of stay in hospitals and the destination on discharge. This paper describes how PHTST-based clustering can be used for modelling delayed discharge and its effects in a stroke care unit, especially the extra beds required, additional cost, and bed blocking. The PHTST length of stay distribution of each group of patients (each PHTST node) is modelled separately as a finite state continuous-time Markov chain using Coxian-phase-type distributions. Delayed discharge patients wai...
Journal of Clinical Speech and Language Studies, 2008
Background: The high prevalence of swallowing problems and aspiration in stroke patients has been... more Background: The high prevalence of swallowing problems and aspiration in stroke patients has been well documented. A reliable swallowing assessment that can accurately determine potential aspiration risk is necessary. The most recent adjunct to the clinical bedside assessment has been the use of pulse oximetry. Purpose: This study examines whether the use of oxygen saturation levels as measured by pulse oximetry can reliably predict the presence of aspiration or penetration of acute dysphagic stroke patients. Methods: This prospective study compared results of pulse oximetry in 20 people with dysphagia post stroke with normal controls. Fiberoptic Endoscopic Evaluation of the Swallow (FEES) was used to confirm the presence of aspiration or penetration. The FEES and pulse oximetry readings were taken simultaneously. Investigators evaluated the results of each test independently to avoid bias. Results: The results confirmed that saturation levels are lower in people with dysphagia post...
In our previous work we proposed a special class of survival distribution called Mixture distribu... more In our previous work we proposed a special class of survival distribution called Mixture distribution survival trees, which are constructed by approximating different nodes in the tree by distinct types of mixture distributions to achieve more improvement in the likelihood function and thus the improved within node homogeneity. We proposed its applications in modelling hospital length of stay and clustering patients into clinically meaningful patient groups, where partitioning was based on covariates representing patient characteristics such as gender, age at the time of admission, and primary diagnosis code. This paper proposes extended Mixture distribution survival trees and demonstrates its applications to patient pathway prognostication and to examine the relationship between hospital length of stay and/or treatment outcome. 5 year retrospective data of patients admitted to Belfast City Hospital with a diagnosis of stroke is used to illustrate the approach. KeywordsStochastic mo...
Medical Research Society measured in the lead showing maximal elevation on a 12 lead ECG taken on... more Medical Research Society measured in the lead showing maximal elevation on a 12 lead ECG taken on admission and from the same lead at 3.5 hours. ST segment shift was expressed as the fractional chan,ge STl-ST2/STl (Hogg KJ et a1 BHJ 1988;60:275). A fractional change of r0.05 was taken as evidence of reperfusion. 12 patients reperfused. Levels of A and NA in reperfused (R) and nonreperfused (NR) were: Adrenaline Noradrenaline R NR R NR Baseline 1.73k0.37 1.56k0.4 4.27k0.62 4.52k0.57 4 hours 0.62k0.16 1.15k0.45 2.76?0.44* 5.39k0.84 (meankSEM; *p < 0.01 compared with non reperfused) In patients with evidence of reperfusion there was a decline in levels of NA at 4 hours in contrast to a small rise in those not reperfusing. Patients who reperfused showed no reduction in cumulative creatine kinase release, pulse rate or blood pressure compared with those who did not. We conclude that ECG evidence of early reperfusion is accompanied by a reduction in sympathetic activation. An early reduction in sympathetic activlty may be one of the beneficial effects of early reperfusion.
We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid inpu... more We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid input in patients during the acute phase of a first stroke. Fifteen consecutive patients were studied (median age 79) and their blood sampled on days 0, 1, 2, 3, 7 and 14. Plasma osmolality was related to fluid input over days 0-3 (p = 0.0013) and AVP over 14 days (p less than 0.001). Patients with a poor outcome had higher AVP concentrations (p = 0.02). Those on intravenous fluids received a higher volume (p less than 0.01) and had a lower plasma osmolality (p = 0.04). The results of this preliminary study indicate that a standard regime for fluid input is inappropriate.
About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some ki... more About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some kind [1]. The patient with a perceptual disorder may ignore his surroundings on the affected side of his body; he may even deny ownership of his weak limbs. The major perceptual disorders in stroke are: neglect (also called unilateral visual neglect), disordered spatial orientation, and denial. Any combination of these abnormalities can occur, and none can be reliably diagnosed on the basis of any single test.
About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some ki... more About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some kind [1]. The patient with a perceptual disorder may ignore his surroundings on the affected side of his body; he may even deny ownership of his weak limbs. The major perceptual disorders in stroke are: neglect (also called unilateral visual neglect), disordered spatial orientation, and denial. Any combination of these abnormalities can occur, and none can be reliably diagnosed on the basis of any single test.
We studied the relation of reactive hyperglycemia, stress hormone response, and outcome in 23 con... more We studied the relation of reactive hyperglycemia, stress hormone response, and outcome in 23 consecutive elderly patients (median age 80 [range 75-92] years) following an acute first stroke. The median delay from the onset of the stroke to the first blood sample (day 0) was ...
Background: after stroke, visual impairment may exacerbate the impact of other impairments on ove... more Background: after stroke, visual impairment may exacerbate the impact of other impairments on overall disability and negatively influence rehabilitation. Objective: to examine the visual status of patients after stroke and determine whether this can be improved by simple interventions. Design: prospective study. Setting: stroke rehabilitation unit in a Belfast teaching hospital. Subjects: 77 consecutive patients admitted for rehabilitation after acute stroke. Methods: full optometric and ophthalmic assessment within 2 weeks of admission. Results: of 70 patients with glasses, 19 did not have their glasses in hospital before prompting and 18 had glasses in unacceptable condition. Twenty patients had impaired visual acuity (6/12 or worse) with existing glasses (if helpful); 11 of these improved to better than 6/12 with refractive correction. Conclusions: stroke professionals need to enquire about patients ’ spectacles and assess their condition. Patients with reduced visual acuity in t...
Background: Although Thrombolysis has been licensed in the UK since 2003, it is still administere... more Background: Although Thrombolysis has been licensed in the UK since 2003, it is still administered only to a small percentage of eligible patients. Aim: We consider the impact of investing the impact of thrombolysis on important acute stroke services, and the effect on quality of life. The concept is illustrated using data from the Northern Ireland Stroke Service. Design: Retrospective study. Methods: We first present results of survival analysis utilizing length of stay (LOS) for discharge destinations, based on data from the Belfast City Hospital (BCH). None of these patients actually received thrombolysis but from those who would have been eligible, we created two initial groups, the first representing a scenario where they received thrombolysis and the second comprising those who do not receive thrombolysis. On the basis of the survival analysis, we created several subgroups based on discharge destination. We then developed a discrete event simulation (DES) model, where each group is a patient pathway within the simulation. Coxian phase type distributions were used to model the group LOS. Various scenarios were explored focusing on cost-effectiveness across hospital, community and social services had thrombolysis been administered to these patients, and the possible improvement in quality of life, should the proportion of patients who are administered thrombolysis be increased. Our aim in simulating various scenarios for this historical group of patients is to assess what the cost-effectiveness of thrombolysis would have been under different scenarios; from this we can infer the likely cost-effectiveness of future policies. Results: The cost of thrombolysis is offset by reduction in hospital, community rehabilitation and institutional care costs, with a corresponding improvement in quality of life. Conclusion: Our model suggests that provision of thrombolysis would produce moderate overall improvement to the service assuming current levels of funding.
Stroke disease is the third leading cause of death in the UK, placing a heavy burden on society a... more Stroke disease is the third leading cause of death in the UK, placing a heavy burden on society at a cost of 7 billion pounds per year. Prolonged length of stay in hospital is considered to be an inefficient use of hospital resources. In this paper we present results of survival analysis that utilise length of stay and destination as outcome measures, based on data from the Belfast City Hospital. Survival probabilities were determined using Kaplan-Meier survival curves and log rank tests. Multivariate Cox proportional hazards models were also fitted to identify independent predictors of length of stay including age, gender and diagnosis. Elderly patients showed a decreased hazard ratio of discharge. However, gender was not a significant hazard risk for length of stay in hospital. Those patients with a diagnosis of cerebral haemorrhage showed an increased hazard ratio and hence were most likely to have a shorter length of stay and to die in hospital. Those who were eventually discharged to a Private Nursing Home had the lowest probability of early discharge. On the basis of these results we have created several groups, stratified by age, gender diagnosis and destination. These groups are then used to form the basis of a simulation model where each group is a patient pathway within the simulation. Various scenarios are explored with a particular focus on the potential efficiency gains if length of stay in hospital, prior to discharge to a Private Nursing Home, can be reduced.
Your article is protected by copyright and all rights are held exclusively by Springer Science+Bu... more Your article is protected by copyright and all rights are held exclusively by Springer Science+Business Media, LLC. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.
Results Almost 80% of surviving patients (n=691) were discharged home and a small number (n=55) ... more Results Almost 80% of surviving patients (n=691) were discharged home and a small number (n=55) were readmitted. Approximately 17% (113/649) were randomized. There were no statistically significant differences in hospital duration, costs, or outcome measures at baseline and ...
Osteitis pubis has been reported following pelvic surgery, childbirth and in athletes. We describ... more Osteitis pubis has been reported following pelvic surgery, childbirth and in athletes. We describe a case involving an elderly woman, in which none of the predisposing factors were present. Difficulties in diagnosis, with particular reference to the elderly, are highlighted.
The problem of hospital patients’ delayed discharge or ‘bed blocking’ has long been a challenge f... more The problem of hospital patients’ delayed discharge or ‘bed blocking’ has long been a challenge for healthcare managers and policymakers. It negatively affects the hospital performance metrics and has other severe consequences for the healthcare system, such as affecting patients’ health. In our previous work, we proposed the phase-type survival tree (PHTST)-based analysis to cluster patients into clinically meaningful patient groups and an extension of this approach to examine the relationship between the length of stay in hospitals and the destination on discharge. This paper describes how PHTST-based clustering can be used for modelling delayed discharge and its effects in a stroke care unit, especially the extra beds required, additional cost, and bed blocking. The PHTST length of stay distribution of each group of patients (each PHTST node) is modelled separately as a finite state continuous-time Markov chain using Coxian-phase-type distributions. Delayed discharge patients wai...
Journal of Clinical Speech and Language Studies, 2008
Background: The high prevalence of swallowing problems and aspiration in stroke patients has been... more Background: The high prevalence of swallowing problems and aspiration in stroke patients has been well documented. A reliable swallowing assessment that can accurately determine potential aspiration risk is necessary. The most recent adjunct to the clinical bedside assessment has been the use of pulse oximetry. Purpose: This study examines whether the use of oxygen saturation levels as measured by pulse oximetry can reliably predict the presence of aspiration or penetration of acute dysphagic stroke patients. Methods: This prospective study compared results of pulse oximetry in 20 people with dysphagia post stroke with normal controls. Fiberoptic Endoscopic Evaluation of the Swallow (FEES) was used to confirm the presence of aspiration or penetration. The FEES and pulse oximetry readings were taken simultaneously. Investigators evaluated the results of each test independently to avoid bias. Results: The results confirmed that saturation levels are lower in people with dysphagia post...
In our previous work we proposed a special class of survival distribution called Mixture distribu... more In our previous work we proposed a special class of survival distribution called Mixture distribution survival trees, which are constructed by approximating different nodes in the tree by distinct types of mixture distributions to achieve more improvement in the likelihood function and thus the improved within node homogeneity. We proposed its applications in modelling hospital length of stay and clustering patients into clinically meaningful patient groups, where partitioning was based on covariates representing patient characteristics such as gender, age at the time of admission, and primary diagnosis code. This paper proposes extended Mixture distribution survival trees and demonstrates its applications to patient pathway prognostication and to examine the relationship between hospital length of stay and/or treatment outcome. 5 year retrospective data of patients admitted to Belfast City Hospital with a diagnosis of stroke is used to illustrate the approach. KeywordsStochastic mo...
Medical Research Society measured in the lead showing maximal elevation on a 12 lead ECG taken on... more Medical Research Society measured in the lead showing maximal elevation on a 12 lead ECG taken on admission and from the same lead at 3.5 hours. ST segment shift was expressed as the fractional chan,ge STl-ST2/STl (Hogg KJ et a1 BHJ 1988;60:275). A fractional change of r0.05 was taken as evidence of reperfusion. 12 patients reperfused. Levels of A and NA in reperfused (R) and nonreperfused (NR) were: Adrenaline Noradrenaline R NR R NR Baseline 1.73k0.37 1.56k0.4 4.27k0.62 4.52k0.57 4 hours 0.62k0.16 1.15k0.45 2.76?0.44* 5.39k0.84 (meankSEM; *p < 0.01 compared with non reperfused) In patients with evidence of reperfusion there was a decline in levels of NA at 4 hours in contrast to a small rise in those not reperfusing. Patients who reperfused showed no reduction in cumulative creatine kinase release, pulse rate or blood pressure compared with those who did not. We conclude that ECG evidence of early reperfusion is accompanied by a reduction in sympathetic activation. An early reduction in sympathetic activlty may be one of the beneficial effects of early reperfusion.
We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid inpu... more We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid input in patients during the acute phase of a first stroke. Fifteen consecutive patients were studied (median age 79) and their blood sampled on days 0, 1, 2, 3, 7 and 14. Plasma osmolality was related to fluid input over days 0-3 (p = 0.0013) and AVP over 14 days (p less than 0.001). Patients with a poor outcome had higher AVP concentrations (p = 0.02). Those on intravenous fluids received a higher volume (p less than 0.01) and had a lower plasma osmolality (p = 0.04). The results of this preliminary study indicate that a standard regime for fluid input is inappropriate.
About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some ki... more About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some kind [1]. The patient with a perceptual disorder may ignore his surroundings on the affected side of his body; he may even deny ownership of his weak limbs. The major perceptual disorders in stroke are: neglect (also called unilateral visual neglect), disordered spatial orientation, and denial. Any combination of these abnormalities can occur, and none can be reliably diagnosed on the basis of any single test.
About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some ki... more About 25% of patients who fail to recover fully from stroke have a perceptual disorder of some kind [1]. The patient with a perceptual disorder may ignore his surroundings on the affected side of his body; he may even deny ownership of his weak limbs. The major perceptual disorders in stroke are: neglect (also called unilateral visual neglect), disordered spatial orientation, and denial. Any combination of these abnormalities can occur, and none can be reliably diagnosed on the basis of any single test.
We studied the relation of reactive hyperglycemia, stress hormone response, and outcome in 23 con... more We studied the relation of reactive hyperglycemia, stress hormone response, and outcome in 23 consecutive elderly patients (median age 80 [range 75-92] years) following an acute first stroke. The median delay from the onset of the stroke to the first blood sample (day 0) was ...
Background: after stroke, visual impairment may exacerbate the impact of other impairments on ove... more Background: after stroke, visual impairment may exacerbate the impact of other impairments on overall disability and negatively influence rehabilitation. Objective: to examine the visual status of patients after stroke and determine whether this can be improved by simple interventions. Design: prospective study. Setting: stroke rehabilitation unit in a Belfast teaching hospital. Subjects: 77 consecutive patients admitted for rehabilitation after acute stroke. Methods: full optometric and ophthalmic assessment within 2 weeks of admission. Results: of 70 patients with glasses, 19 did not have their glasses in hospital before prompting and 18 had glasses in unacceptable condition. Twenty patients had impaired visual acuity (6/12 or worse) with existing glasses (if helpful); 11 of these improved to better than 6/12 with refractive correction. Conclusions: stroke professionals need to enquire about patients ’ spectacles and assess their condition. Patients with reduced visual acuity in t...
Background: Although Thrombolysis has been licensed in the UK since 2003, it is still administere... more Background: Although Thrombolysis has been licensed in the UK since 2003, it is still administered only to a small percentage of eligible patients. Aim: We consider the impact of investing the impact of thrombolysis on important acute stroke services, and the effect on quality of life. The concept is illustrated using data from the Northern Ireland Stroke Service. Design: Retrospective study. Methods: We first present results of survival analysis utilizing length of stay (LOS) for discharge destinations, based on data from the Belfast City Hospital (BCH). None of these patients actually received thrombolysis but from those who would have been eligible, we created two initial groups, the first representing a scenario where they received thrombolysis and the second comprising those who do not receive thrombolysis. On the basis of the survival analysis, we created several subgroups based on discharge destination. We then developed a discrete event simulation (DES) model, where each group is a patient pathway within the simulation. Coxian phase type distributions were used to model the group LOS. Various scenarios were explored focusing on cost-effectiveness across hospital, community and social services had thrombolysis been administered to these patients, and the possible improvement in quality of life, should the proportion of patients who are administered thrombolysis be increased. Our aim in simulating various scenarios for this historical group of patients is to assess what the cost-effectiveness of thrombolysis would have been under different scenarios; from this we can infer the likely cost-effectiveness of future policies. Results: The cost of thrombolysis is offset by reduction in hospital, community rehabilitation and institutional care costs, with a corresponding improvement in quality of life. Conclusion: Our model suggests that provision of thrombolysis would produce moderate overall improvement to the service assuming current levels of funding.
Stroke disease is the third leading cause of death in the UK, placing a heavy burden on society a... more Stroke disease is the third leading cause of death in the UK, placing a heavy burden on society at a cost of 7 billion pounds per year. Prolonged length of stay in hospital is considered to be an inefficient use of hospital resources. In this paper we present results of survival analysis that utilise length of stay and destination as outcome measures, based on data from the Belfast City Hospital. Survival probabilities were determined using Kaplan-Meier survival curves and log rank tests. Multivariate Cox proportional hazards models were also fitted to identify independent predictors of length of stay including age, gender and diagnosis. Elderly patients showed a decreased hazard ratio of discharge. However, gender was not a significant hazard risk for length of stay in hospital. Those patients with a diagnosis of cerebral haemorrhage showed an increased hazard ratio and hence were most likely to have a shorter length of stay and to die in hospital. Those who were eventually discharged to a Private Nursing Home had the lowest probability of early discharge. On the basis of these results we have created several groups, stratified by age, gender diagnosis and destination. These groups are then used to form the basis of a simulation model where each group is a patient pathway within the simulation. Various scenarios are explored with a particular focus on the potential efficiency gains if length of stay in hospital, prior to discharge to a Private Nursing Home, can be reduced.
Your article is protected by copyright and all rights are held exclusively by Springer Science+Bu... more Your article is protected by copyright and all rights are held exclusively by Springer Science+Business Media, LLC. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.
Results Almost 80% of surviving patients (n=691) were discharged home and a small number (n=55) ... more Results Almost 80% of surviving patients (n=691) were discharged home and a small number (n=55) were readmitted. Approximately 17% (113/649) were randomized. There were no statistically significant differences in hospital duration, costs, or outcome measures at baseline and ...
Osteitis pubis has been reported following pelvic surgery, childbirth and in athletes. We describ... more Osteitis pubis has been reported following pelvic surgery, childbirth and in athletes. We describe a case involving an elderly woman, in which none of the predisposing factors were present. Difficulties in diagnosis, with particular reference to the elderly, are highlighted.
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Papers by Ken Fullerton