PubMed Health⌕ Search

Biomedical subjects

D R Baldwin

Publications and source records attributed to D R Baldwin.

At least 19 recordsLinked to original sources
PubMed2005

Under utilisation of the 2-week wait initiative for lung cancer by primary care and its effect on the urgent referral pathway.

The '2-week wait' scheme for referral of patients with cancer to secondary care coincided with the introduction of Department of Health (DoH) Guidelines on referral of patients with suspected lung cancer. The aim of this study was to examine the impact of this process on the urgent referral pathway for lung cancer. Medical records of all patients referred with suspected lung cancer were reviewed for the year prior to introduction of the 2-week wait and DoH guidelines and for the subsequent 24 months. A total of 1044 patients were referred, of which 650 (62%) were found to have malignancy. In the first and second years of the 2-week wait scheme, only 57 and 58% were referred via the scheme. Department of Health guidelines were followed in all but a small number. Median wait time increased from 7 to 9 days. The proportion of all urgent referrals seen within 2 weeks fell from 84 to 71%. The proportion of non-2-week wait urgent referrals being seen within 2 weeks was only 75.5% in the first year of the scheme and fell further to 60.9% in the second year. The absolute number of referrals rose and the proportion having cancer fell from 78% before the scheme to 46% in the second year. During this time, there was no change in stage at presentation. Symptoms were not helpful in discriminating benign from malignant disease and haemoptysis was actually more common in the benign group. However, over 50% of patients in the benign group were appropriate to be seen in secondary care. The 2-week wait scheme has so far failed to reduced waiting times for lung cancer. The findings of this study suggest that this is partly due to continued usage of urgent referral routes outside the 2-week wait scheme and secondly due to a large increase in referrals, probably generated by the introduction of the DoH guidelines. Some adjustment to the guidelines may be appropriate to reflect more emphasis on the early performance of a chest X-ray and the use of direct access to other imaging modalities such as CT. Patients referred outside the 2-week wait are disadvantaged and thus practitioners would be wise to refer all their patients through the 2-week wait system.

Adult↗
PubMed2002

Interpretation of occupational peak flow records: level of agreement between expert clinicians and Oasys-2.

BACKGROUND: Oasys-2 is a validated diagnostic aid for occupational asthma that interprets peak expiratory flow (PEF) records as well as generating summary plots. The system removes inconsistency in interpretation, which is important if there is limited agreement between experts. A study was undertaken to assess the level of agreement between expert clinicians interpreting serial PEF measurements in relation to work exposure and to compare the responses given by Oasys-2. METHOD: 35 PEF records from workers under investigation for suspected occupational asthma were available for review. Records included details of nature of work, intercurrent illness, drug therapy, predicted PEF, rest periods, and holidays. Simple plots of PEF and the Oasys-2 generated plots were available. Experts were advised that approximately 1 hour was available to review the records. They were asked to score each work-rest-work (WRW) period and each rest-work-rest (RWR) period for evidence of occupational effect. At the end of each record scores of 0-100% were given for evidence of "asthma" and "occupational effect" for the whole record. Kappa values were calculated for each scored period and for the opinions on the whole record. The scores were converted into four groups (0-25%, 26-50%, 51-75%, 76-100%) and two groups (0-50% and 51-100%) for analysis. This is relevant to scores produced by Oasys-2. Agreement between Oasys-2 scores and each expert was calculated. RESULTS: 24 of 35 records were analysed by seven experts in the allotted time. For whole record occupational effect, median kappa values were 0.83 (range 0.56-0.94) for two groups and 0.62 (0.11-0.83) for four groups. For asthma, median kappa values were 0.58 (0-0.67) and 0.42 (0.15-0.70) for two and four groups respectively. For all WRW and RWR periods kappa values were 0.84 (0.42-0.94) and 0.70 (0.46-0.87) respectively. Agreement between Oasys-2 and individual experts showed a median kappa value of 0.75 (0.50-0.92) for two groups and 0.50 (0.39-0.70) for four groups. Kappa values for the median expert score v Oasys-2 were 0.75 for two groups and 0.67 for four groups. Agreement was poor for records with intermediate probability, as defined by Oasys-2. CONCLUSION: Considerable variation in agreement was seen in expert interpretation of occupational PEF records which may lead to inconsistencies in diagnosis of occupational asthma. There is a need for an objective scoring system which removes human variability, such as that provided by Oasys-2.

Asthma↗
PubMed2002

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND: Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography. METHODS: Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later. RESULTS: 33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy. CONCLUSION: Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

Adult↗
PubMed2000

Glucose uptake increases relative to oxygen consumption during short-term hibernation.

BACKGROUND: Although glucose uptake is increased in chronically hypoperfused, viable myocardium, the dynamic changes in glucose uptake relative to oxygen consumption in "short-term" models of hibernation have not been fully explored. METHODS: 14 anesthetized swine were instrumented with an hydraulic occluder and flow probe on the proximal LAD artery. Blood flow was reduced approximately 30% for 1 hour. Myocardial blood flow and uptake of oxygen, free fatty acids, glucose and lactate were determined in the LAD region at baseline and at 10, 30, and 60 minutes of ischemia. Transmural biopsies for ATP and creatine phosphate (CP) were obtained in the LAD region prior to and at 15 and 45 minutes of ischemia. In 5 animals, glycogen was assayed at baseline and at the end of 60 minutes of ischemia. RESULTS: In the LAD region, myocardial oxygen consumption was reduced from 2.06 +/- 0.16 micromol/min/gram to 1.46 +/- 0.13 micromol/min/gram (P < 0.05). By 15 minutes of ischemia, transmural creatine phosphate fell from 7.48 +/- 0.76 micromol/g-wet weight at baseline to 6.19 +/- 0.32 micromol/g-wet weight (P < 0.05) but normalized by 45 minutes of ischemia (7.39 +/- 0.56 micromol/g-wet weight; NS). Between 10 and 60 minutes of constant flow reduction, glucose uptake as a percentage of MVO2 increased from 3 +/- 2% to 10 +/- 2% (P < 0.05) while lactate uptake increased from -9 +/- 9% to -1 +/- 2% (P < 0.05). Glycogen decreased from 27.8 +/- 3.7 at baseline to 16.9 +/- 1.2 micromol/g-wet weight at end-ischemia. CONCLUSIONS: In this model of short-term hibernation, glucose and lactate uptake increase relative to oxygen consumption during sustained ischemia, and temporally coincide with the recovery of bioenergetics. The findings are consistent with the notion that glycolytically derived ATP is important for the maintainance of energy supply during sustained ischemia.

Animals↗
PubMed2000

Questionnaire survey of male infertility in cystic fibrosis.

Most male cystic fibrosis (CF) patients are infertile due to obstructive azospermia but little is known about the best time to counsel patients on infertility. All male patients attending the Adult Nottingham CF unit were invited to complete an anonymous questionnaire on infertility. The response rate was 60%. The median age that the patients first became aware of male infertility was 17 years (range 13-24) but the preferred age of receiving this information was 14 years (range 8-16). Patients first learnt about male infertility from the CF team (six patients), parents (five), from written information (two) or unexpectedly (five). Five out of 18 patients had undergone seminal analysis at a median age of 26 years but 17/18 patients felt that this should be offered routinely. Our survey has shown that patients would like infertility discussions at a younger age and routine seminal analysis.

Adolescent↗
PubMed1999

Development of an expert system for the interpretation of serial peak expiratory flow measurements in the diagnosis of occupational asthma. Midlands Thoracic Society Research Group.

If asthma is due to work exposures there must be a relation between these exposures and the asthma. Asthma causes airway hyperresponsiveness and obstruction; the obstruction can be measured with portable meters, which usually measure peak expiratory flow, or sometimes forced expiratory volume in 1 second (FEV1). These can be measured serially (for instance 2 hourly) over several weeks at and away from work. Once occupational asthma develops, the asthma will be induced by many non-specific triggers common to non-occupational asthma. The challenge is to identify changes in peak expiratory flow due to work among other non-occupational causes. Standard statistical tests have been found to be insensitive or non-specific, principally because of the variable period for deterioration to occur after exposure, and the sometimes prolonged time for recovery to occur, such that days away from work may initially have lower measurements than days at work. A computer assisted diagnostic aid (Oasys) has been developed to separate occupational from non-occupational causes of airflow obstruction. Oasys-2 is based on a discriminant analysis, and achieved a sensitivity of 75% and a specificity of at least 94%; therefore peak expiratory flow monitoring combined with Oasys-2 analysis is better to confirm than to exclude occupational asthma. A neural network version in development has improved on this. Both have been based on expert interpretation of peak flow measurements plotted as daily maximum, mean, and minimum, with the first reading at work taken as the first reading of the day. Oasys has been evaluated with independent criteria against measurements made in a wide range of occupational situations. Oasys is sufficiently developed to be the initial method for the confirmation, although less so for exclusion of occupational asthma.

Asthma↗
PubMed1999

Comparison of two new methods for the measurement of lung volumes with two standard methods.

BACKGROUND: The two most commonly used methods for the measurement of lung volumes are helium dilution and body plethysmography. Two methods have been developed which are both easier and less time consuming to perform. Mathematical modelling uses complex calculations from the flow-volume loop to derive total lung capacity (TLC), and the nitrogen balance technique uses nitrogen from the atmosphere to calculate lung volume in a similar way to helium dilution. This study was designed to compare the two new methods with the two standard methods. METHODS: Sixty one subjects were studied, 23 with normal lung function, 17 with restrictive airway disease, and 21 with obstructive ventilatory defects. Each subject underwent repeated measurements of TLC by each of the four methods in random order. Reproducible values were obtained for each method according to BTS/ARTP guidelines. Bland-Altman plots were constructed for comparisons between the methods and paired t tests were used to assess differences in means. RESULTS: Bland-Altman plots showed that the differences between body plethysmography and helium dilution fell into clinically acceptable ranges (agreement limits +/-0.9 l). The agreement between mathematical modelling or the nitrogen balance technique and helium dilution or body plethysmography was poor (+/-1.8-3.4 l), especially for subjects with airflow obstruction. CONCLUSIONS: Neither of the new methods agrees sufficiently with standard methods to be useful in a clinical setting.

Adult↗
PubMed1999

How do general practitioners respond to reports of abnormal chest X-rays?

General practitioners (GPs) in the UK have long had direct access to hospital radiological services, which in theory shortens investigation time and improves the quality of service. Chest X-rays (CXRs) account for a substantial proportion of requests, and we investigated what happened when an abnormality was detected. In one year, 204 GPs in the Nottingham area requested CXRs in 605 patients. 362 were reported normal, 165 abnormal but hospital follow-up not indicated and 71 abnormal with radiological follow-up or hospital referral indicated (mass lesion suspicious of tumours 27, infective shadowing 35, other 9). 64 of the 71 were seen in hospital within three months, and in those with suspected cancer the median time to follow-up was 20 days. These results show that GPs do act on the results of abnormal CXRs, but only 37% of those with a mass suspicious of cancer were seen in hospital within two weeks as recommended by the British Thoracic Society. Time might be saved if GPs agreed to direct referral from the radiology department to respiratory physicians.

Adolescent↗
PubMed1998

Effect of two types of mandibular advancement splints on snoring and obstructive sleep apnoea.

Snoring and obstructive sleep apnoea (OSA) both seem at least to be associated with narrowing of the upper airway and sleep-induced loss of muscle-tone. Mandibular advancement splints (MAS) have been proposed as a relatively simple method to increase oro- and hypo-pharyngeal dimensions thereby increasing the size of the airway. However, data on their effectiveness are conflicting and there are no clear indications as to which design is most effective or when they should be used. The effects of two designs of splint (types A and B) have been evaluated in 14 and nine subjects, respectively, using the Epworth Sleepiness Score (ESS) and domiciliary sleep monitoring on separate nights. Both splints reduced the median ESS (type A from 12 to 4.5; P = 0.003, type B from 7 to 4; P = 0.005). The apnoea-hypopnoea index was not affected by type A, but was reduced from 7.1 to 0.8; P = 0.005 by type B splints. There was evidence of a small improvement in overnight oxygen saturation for type B splints (P = 0.02). The splints were well tolerated and continued to be used nightly by 18 subjects. Mandibular advancement splints may offer a simple and effective alternative for the treatment of snoring and mild OSA in selected patients. Splint design may have considerable bearing on efficacy.

Adult↗
PubMed1998

Comparative clinical and physiological features of Maori, Pacific Islanders and Europeans with sleep related breathing disorders.

UNLABELLED: Recent studies have suggested that there is a familial association of sleep apnoea syndrome and that this is not entirely explained by inheritance of known risk factors. Maori (M) and Pacific Islanders (PI) have many of the body habitus features associated with sleep apnoea and therefore might be expected to exhibit more severe disease than Europeans (E). OBJECTIVE: To compare the clinical and physiological characteristics of the different ethnic groups and to determine if race was an independent predictor of severity of sleep apnoea. METHODOLOGY: A prospective evaluation of patients attending the Sleep Disordered Breathing Clinic which serves the whole of Auckland (population 1.1 million), New Zealand was conducted for the period July 1994 to August 1995. The evaluation included history including a 26 question questionnaire, Epworth sleepiness score, examination, and where indicated, full polysomnography. RESULTS: A total of 233 patients (154 E, 48 M and 33 PI), underwent full polysomnography. Forty-one (85%) of the M and 31 (94%) of PI had obstructive or mixed sleep apnoea compared with only 74 (49%) of the E (P < 0.0001; chi 2). There were few racial differences in the responses to the sleep questionnaire. M and PI were shown to have much greater neck and waist circumference and body mass indices. Severity parameters (apnoea-hypopnoea index, wake and minimum oxygen saturation, and apnoea duration) were greater for both M and PI compared with E (P < 0.001; Mann-Whitney U-test). Stepwise regression identified neck size, body mass index and age as independent predictors of severity. CONCLUSION: When other factors were controlled for, race was not an important independent predictor of severity of sleep apnoea.

Adult↗
PubMed1998

Coronary bypass grafting for single-vessel coronary artery disease: a 17-year review with short- and long-term follow-up.

STUDY OBJECTIVES: We reviewed our short- (30 days) and long-term (up to 17 years) experience with surgical revascularization for patients with angiographically documented isolated single-vessel coronary artery disease. DESIGN: Retrospective study of single-vessel coronary artery bypass procedures performed from January 1980 through June 1996. During this time, 100 consecutive patients underwent a single-vessel coronary artery bypass. All patients were men with a mean age of 59+/-9 years (range, 35 to 78 years) and a mean ejection fraction of 56+/-8% (range, 35 to 77%). The vessels bypassed included the left anterior descending in 66 (66%), right coronary artery in 31 (31%), and the obtuse marginal in 3 (3%). RESULTS: Short-term results reveal no deaths and six (6.0%) complications. Long-term follow-up by chart review and telephone survey was available in 87 (87%) patients at a mean of 46.9 months (range, 12 to 151 months). Cumulative freedom from angina and repeated revascularization was 93% and 98% at 1 year and 55% and 81% at 10 years, respectively (Kaplan-Meier). CONCLUSION: Single-vessel coronary artery bypass for isolated single-vessel disease can be performed with minimal morbidity and no mortality and provides excellent long-term relief of angina.

Adult↗
PubMed1997

Principals of design and evaluation of an information system for a department of respiratory medicine.

OBJECTIVES: To evaluate a departmental computer system. DESIGN: a. Direct comparison of the time taken to use a manual system with the time taken to use a computer system for lung function evaluation, loan of equipment and production of correspondence. b. Analysis of the accuracy of data capture before and after the introduction of the computer system. c. Analysis of the comparative running costs of the manual and computer systems. SETTING: Within a department of respiratory medicine serving a hospital of 1323 beds. MAIN OUTCOME MEASURES: a. Time taken to perform functions with the assistance of computerised methods, in comparison to the manual method used alone. b. Accuracy of data capture. c. Relative running costs. RESULTS: a. The computer system (CS) was significantly faster than the manual system (MS) for lung function evaluation (CS = 7.63 min/test, MS = 12.25 min/test), loan of equipment (CS = 0.40 min/loan, MS = 2.07 min/loan), and checking for overdue equipment (CS = 0.49 s/record, MS = 9 s/record). The production of correspondence was slightly slower with the computer (CS = 9.30 min/letter, MS = 8.54 min/letter). b. All outpatient episodes, but only 43 of 65 (66%) of in-patient episodes, were captured. Lung function and managerial report data were accurate using both manual and computerised methods. The manual system for equipment loans was inefficient, and use of the computer resulted in the recovery of 221 nebulisers. c. Development costs for 1988-1990 were high (72,178 pounds). Only 1200 pounds to 1845 pounds per year was recovered directly from staff time saved by the computer but larger savings resulted from changes in work practice (4049-4765 pounds). After 10 years the projected deficit is 10,000 pounds per annum in running costs. CONCLUSIONS: In comparison with the manual methods, the computer system has shown significant advantages which provide accurate information, with significant favourable effects on working practices. In evaluating computer systems used in clinical practice it is essential to ensure that the projected work practice benefits are achieved without unacceptable costs in staff time, inaccurate data and high financial outlay.

Computer Systems↗
PubMed1997

The effects of voluntary exercise and immobilization on humoral immunity and endocrine responses in rats.

This research examined the effect of type of stressor (physical vs. psychological) on humoral immunity and neuroendocrine responses in male and female rats. Eighty adult Sprague-Dawley rats were assigned to one of the four stress conditions (n = 20 animals/group): 1. Voluntary running (high physical/low psychological stress); 2. immobilization (low physical/high psychological stress); 3. mixed stress (running and immobilization); and 4. cage control group. The experimental manipulations were conducted over a 6-week period for 4 h/day. Five weeks after the start of the study, all animals were immunized with 1 ml of a 10% suspension of sheep red blood cells (SRBC) in saline and sacrificed 1 week later. Data analyses revealed no main effect of stress on any of the immune or endocrine parameters. However, strong gender differences emerged within the stress conditions on these physiological parameters. The stressed female rats displayed an enhanced antibody response to SRBC and a higher percentage of peripheral blood lymphocytes than their male counterparts. However, there were no significant differences between the male and female control animals with respect to these variables. Female rats consistently displayed elevated levels of plasma corticosterone and adrenal norepinephrine across all conditions. In addition, female rats displayed heavier relative organ weights (adrenal and spleen). Taken together, the notion of differential immunity with respect to physical or psychological stress is not supported by the present study.

Animals↗
PubMed1997

Stress and illness in adolescence: issues of race and gender.

There is an abundance of information on the association between stressful life events and illness within the adult population. In contrast, research on this relationship among adolescents is limited. This study evaluated the role of individual differences (gender and race) on the stress-illness relationship within the adolescent population. Participants were 119 adolescents (54 females and 65 males), recruited from two public high schools located in the southeast, who were administered four questionnaires designed to measure levels of stress, anxiety, and illness. Overall, correlational analysis revealed that stress and anxiety were positively correlated with reported illness. However, racial and gender differences did emerge. Although no gender differences were found with regard to the experience of stress, African-American athletes reported a higher frequency of stressful life events than did their Euro-American counterparts. Further, African-American adolescents reported a lower frequency of illness than did the Euro-Americans. Females reported more illnesses than did males. Possible explanations for individual differences in reported stress and illness are discussed.

Adolescent↗
PubMed1996

Myocardial glucose metabolism and ATP levels are decreased two days after global ischemia.

We hypothesized that following reversible myocardial ischemia recovery of glucose metabolism would be prolonged and would parallel recovery of high energy phosphate levels. Normothermic ischemia was achieved in dogs by aortic cross-clamping for 20 min on cardiopulmonary bypass. Glucose uptake was determined by [18F]fluorodeoxyglucose uptake and positron emission tomography (PET) 1 week pre-ischemia and at 2 and 7 days post-ischemia (n = 8). Oxygen consumption (MVO2) and glucose uptake were also measured by Fick. In a separate group of animals, adenosine triphosphate (ATP) and creatine phosphate (CP) levels were measured by left ventricular/septal biopsies at baseline, 2 days, and 7 days (n = 6). Glucose uptake, as measured by PET, was reduced to 15% of baseline at 2 days post-ischemia and returned to normal by 7 days post-ischemia (P < 0.05). These results were confirmed by Fick measures of glucose uptake. ATP levels were reduced to 49% of pre-ischemic levels at 2 days and returned to baseline by 7 days (P < 0.05). CP and MVO2 levels were normal at 2 and 7 days following ischemia. We conclude that reduced glucose uptake in the presence of intact oxidative metabolism suggests that glucose is not the favored substrate for ATP production following ischemia.

Adenosine Triphosphate↗