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G B Smith

Publications and source records attributed to G B Smith.

At least 37 records · Page 2Linked to original sources
PubMed1999

Analysis of intensive care populations to select possible candidates for high dependency care.

OBJECTIVES: To identify the proportion, and range across intensive care units, of intensive care patients who might potentially be managed on a high dependency unit (HDU) using three different classification systems. METHODS: 8095 adult patients admitted to 15 intensive care units in the south of England between 1 April 1993 and 31 December 1994 were studied. Patients were identified as potential HDU admissions if their APACHE III derived risk of hospital mortality was < or =10%, if they were categorised as a low risk monitor (LRM) patient using the Wagner risk stratification method, or if they did not require advanced respiratory support (ARS). RESULTS: 4146 patients (51.2%) had an APACHE III derived risk of hospital death of < or =10%, 1687 (20.8%) were classified as LRM, and 3860 (47.7%) did not receive ARS. The values for each intensive care unit ranged from 32.8-63.3% (APACHE III group), 7.2-29.9% (LRM group), and 14.4-68.2% (ARS group). No matter which of the three methods was used, there were significant differences between the 15 units (p<0.0001) with regard to the number of potential HDU patients identified within the scored population. CONCLUSIONS: The percentage of intensive care patients who might be more appropriately managed in a HDU varies considerably between hospitals, and depends upon both local circumstances and the method used to define a high dependency patient. However, whichever method is used, it appears that significant numbers of patients of low dependency status currently fill intensive care beds in the units studied. If these analyses are correct, the perceived national shortage in intensive care beds might be improved by the development of HDUs.

APACHE↗
PubMed1999

Comparison of outcome from intensive care admission after adjustment for case mix by the APACHE III prognostic system.

STUDY OBJECTIVES: To evaluate the acute physiology, age, chronic health evaluation III (APACHE III) scoring system in the context of general adult ICUs in the United Kingdom. DESIGN: Prospective, noninterventional, cohort study. SETTING: Seventeen general adult ICUs in a discrete area of southwest England. PATIENTS: 12,793 patients admitted between April 1, 1993 and December 31, 1995. MEASUREMENTS: Sociodemographic and severity-of-illness data were collected for all patients admitted to the study units. Formal goodness-of-fit tests were applied and observed mortality was compared with that predicted by using the APACHE III system. RESULTS: For the group of ICUs as a whole, the risk-adjusted standardized mortality ratio (SMR) was 1.23 (95% confidence intervals, 1.12-1.25). For 11 out of 17 ICUs, the SMR was significantly greater than unity (p < 0.05). Calibration, as tested by Hosmer-Lemeshow statistics, was poor (H2 = 312.54; C2 = 332.85; df = 8; p < 0.01); however, model discrimination was good with a total correct classification rate of 82.9% and an area under the receiver operating characteristic curve of 0.89. CONCLUSIONS: The excess mortality observed after case-mix adjustment using the APACHE III system in this study may be the result of either poor intensive care performance as compared with the United States or a failure of the APACHE III equation to fit the UK data.

APACHE↗
PubMed1998

Conserved active site aspartates and domain-domain interactions in regulatory properties of the sugar kinase superfamily.

The structures of the sugar kinase/heat shock 70/actin superfamily of enzymes show that the active site is located in a deep cleft between two domains whose relative movement defines a domain closure conformational change thought to be involved in the catalytic and regulatory properties of members of the superfamily. To investigate the role of the domain closure in the regulatory behavior, site-directed mutagenesis is used to alter specific domain-domain interactions in Escherichia coli glycerol kinase (EC 2.7.1.30; ATP:glycerol 3-phosphotransferase), a member of this superfamily. Two active site aspartate residues are conserved throughout the superfamily, one (Asp245 in glycerol kinase) which is proposed to act as a general base during catalysis and one (Asp10 in glycerol kinase) which interacts with the Mg(II) ion of the bound Mg(II)-nucleotide complex. Each of these residues participates in domain-domain interactions that are mediated by the bound substrates. The enzymes containing the substitutions Asp245 to Asn (D245N) or Asp10 to Asn (D10N) were purified by affinity chromatography, and the effects of the substitutions on the catalytic properties and regulation by the allosteric effectors, fructose 1,6-bisphosphate (FBP), and the glucose-specific phosphocarrier protein, IIIGlc (also known as IIAGlc), were determined. Each of the residues participates in catalysis; kcat/Katp is decreased 300-fold by the D245N substitution and 100-fold by the D10N substitution. Affinity labeling with the glycerol analog 1,3-dichloroacetone shows that the level of activity seen for the D245N mutant enzyme is not due to deamidation of the substituted asparagine. Each of the substitutions has little effect on regulation by FBP and the apparent affinity for IIIGlc, and the D245N substitution does not affect the extent of inhibition by IIIGlc. However, the D10N substitution decreases the maximum extent of inhibition by IIIGlc from 100 to 60%, thus changing the action of IIIGlc to that of a partial inhibitor. The different sensitivities of the extents of FBP and IIIGlc inhibition to perturbation of a domain-domain interaction mediated by Asp10 suggest that the relations of the actions of these allosteric effectors to the domain closure conformational change are different.

Allosteric Regulation↗
PubMed1998

The effect of lead time bias on severity of illness scoring, mortality prediction and standardised mortality ratio in intensive care--a pilot study.

The effect of lead time bias on severity of illness scoring, mortality prediction and standardised mortality ratios was examined in a pilot study of 76 intensive care (ICU) patients using APACHE II, APACHE III and SAPS II scoring systems. The inclusion of data collected in the period prior to ICU admission increased severity of illness scores and estimated risk of hospital mortality significantly for all three scoring systems (p < 0.01) by up to 14 points and 42.7% (APACHE II), 50 points and 26.3% (APACHE III) and 23 points and 33.4% (SAPS II), respectively. Standardised mortality ratios fell from 0.99 to 0.79 (APACHE II), 0.96 to 0.84 (APACHE III) and 0.75 to 0.64 (SAPS II), but these changes failed to reach statistical significance. Lead time bias had most effect in medical patients and on emergency admissions, and least effect in patients admitted from the operating theatre. These trends suggest that mortality ratios may not necessarily reflect intensive care unit performance and indicate that a larger study of the effect of lead time bias, case mix, pre-ICU care or post-ICU management on standardised mortality ratios is indicated.

Adolescent↗
PubMed1998

Human glutathione S-transferase P1 polymorphisms: relationship to lung tissue enzyme activity and population frequency distribution.

The association between glutathione S-transferase (GST) activity as measured by 1-chloro-2,4-dinitrobenzene (CDNB) conjugation and genotype at exon 5 and exon 6 of the human GSTP1 gene was investigated in normal lung tissue obtained from 34 surgical patients. These samples were genotyped for previously identified polymorphisms in exon 5 (Ile105Val) and exon 6 (Ala114Val) by PCR-RFLP and direct sequencing. GST enzyme activity was significantly lower among individuals with the 105 Val allele. Homozygous Ile/Ile samples (n = 18) had a mean cytosolic CDNB conjugating activity of 74.9 +/- 3.8 nmol/mg per min; heterozygotes (n = 13) had a mean specific activity of 62.1 +/- 4.2 nmol/mg per min and homozygous Val/Val (n = 3) had a mean specific activity of 52.5 +/- 4.5 nmol/mg per min. The CDNB conjugating activity measured for the Ile/Ile genotype group was significantly different from that observed in the Ile/Val group (P = 0.03), and from Ile/Val and Val/Val genotypes combined (P = 0.009). Mean GST activity values were consistently lower in individuals with genotypes containing the 105 valine allele, regardless of smoking exposure. Genotypes at codon 114 were also assessed but the mean GST activity was not significantly lower in individuals with the 114 valine allele. A new haplotype, present in two samples who were homozygous 105Ile and had a 114Val, was identified and proposed as GSTP1*D. Frequencies of the exon 5 and exon 6 polymorphisms were determined in samples obtained from European-Americans, African-Americans and Taiwanese. The differences observed were highly significant suggesting the possibility of GSTP1 genotype-associated, ethnic differences in cancer susceptibility and chemotherapeutic response.

Asian People↗
PubMed1998

Selecting outcomes tools in geropsychiatric home care.

Mental health services are rapidly shifting from acute-based care to community-based care. More adults over the age of 65 years are being treated in the home or community for chronic mental illness. As care moves to the community, funding and regulatory sources are demanding a greater focus on measuring quality of care by assessing and evaluating outcomes. This article outlines the selection of outcome assessment instruments used in geropsychiatric home care.

Aged↗
PubMed1997

The teaching of cardiopulmonary resuscitation in schools in Hampshire.

In order to maximise the number of potential providers of cardiopulmonary resuscitation (CPR) in the community, it has been suggested that a programme of basic life support (BLS) training should be included within the school curriculum. Using a questionnaire sent to 275 schools in south east Hampshire (representing 71,716 pupils), we discovered that BLS was taught at only 26% of schools which replied. The age at which teaching commenced ranged from 7-16 years (mode = 10 years). We estimated that almost 5000 children might currently be trained annually in these schools. Consequently, each year approximately 40% of children in south east Hampshire schools might be exposed to BLS training. On average, schools offering BLS tuition were larger, had more teaching staff and employed a higher proportion of staff who were themselves BLS providers. The majority of BLS teaching was undertaken by school staff (50.9% of schools) and members of the Red Cross, The St. John Ambulance Brigade or statutory ambulance service (30.9%). One school utilised members of the local fire brigade. Only one school offering BLS training to its pupils did not have a staff member trained in CPR.

Adolescent↗
PubMed1997

The laryngeal mask airway and the tracheal route for drug administration.

We undertook a study to observe if a preformed curved plastic cannula, the Trachojet, could be passed blindly down a laryngeal mask airway into the trachea in 100 anaesthetized patients. Using air aspiration and a fibreoptic scope to confirm placement of the cannula, it passed into the trachea in only 27% of patients. The air aspiration technique used for detecting tracheal cannulation was 100% successful when the cannula was inserted fully. We conclude that it may not be possible to gain access to the trachea with a Trachojet for drug administration if a laryngeal mask airway is used to maintain the patient's airway.

Administration, Oral↗
PubMed1997

Prediction of outcome from intensive care: a prospective cohort study comparing Acute Physiology and Chronic Health Evaluation II and III prognostic systems in a United Kingdom intensive care unit.

OBJECTIVE: To evaluate the ability of two prognostic systems to predict hospital mortality in adult intensive care patients. DESIGN: Prospective cohort study. SETTING: A mixed medical and surgical intensive care unit (ICU) in the United Kingdom. PATIENTS: A total of 1,144 patients consecutively admitted to the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Acute Physiology and Chronic Health Evaluation (APACHE) II and III prognostic systems were applied to assess probabilities of hospital mortality, which were compared with the actual outcome. The overall goodness-of-fit of both models was assessed. Hospital death rates were higher than those predicted by each system. Risk estimates showed a strong positive correlation between both systems (nonsurvivors r2 = 0.756, p < .0001; survivors r2 = 0.787, p < .0001). Calibration of APACHE II (chi 2 = 98.6, Lemeshow-Hosmer) was superior to that of APACHE III (chi 2 = 129.8, Lemeshow-Hosmer). The total correct classification rate of APACHE III was greater for all decision criteria applied; the best overall total correct classification rate was 80.6% for APACHE III and 77.9% for APACHE II (both for a decision criterion of 40%). The areas under the receiver operating characteristic curves were 0.806 and 0.847 for APACHE II and III, respectively, confirming the better discrimination of APACHE III. When patients were classified by diagnostic categories, risk predictions did not fit uniformly across the spectrum of disease groups. For both models, mortality ratios were highest for trauma patients and lowest for the group with respiratory disease. APACHE II predictions for patients with gastrointestinal disease were significantly better. Risk estimates for surgical admissions were superior with APACHE II (MR = 1.27) compared with APACHE III (MR = 1.56), but were similar for medical patients (1.22 vs. 1.28 for APACHE II and III, respectively). Bias induced by factors reflecting the clinical practice in an individual ICU (e.g., admission criteria, treatment before admission) may have considerable impact on risk estimates. The identification of such factors appears to be a prerequisite for the meaningful interpretation of observed and predicted death rates on the individual ICU level. CONCLUSIONS: Both predictive models demonstrated a similar degree of overall goodness-of-fit. APACHE II showed better calibration, but discrimination was better with APACHE III. Hospital mortality was higher than predicted by both models, but was underestimated to a greater degree by APACHE III. Risk estimates by both models showed considerable variation across the disease spectrum of ICU patients. Risk predictions for surgical patients and patients with gastrointestinal disease were better with APACHE II. Factors reflecting the clinical practice of an individual ICU are not accounted for by APACHE II and III. Overall, the performance of APACHE III was not superior to that of its predecessor for a cohort of United Kingdom ICU patients; for certain diagnostic categories, APACHE III performed worse than APACHE II despite an improved system of disease classification.

APACHE↗