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Biomedical subjects

G M Hall

Publications and source records attributed to G M Hall.

At least 37 records · Page 2Linked to original sources
PubMed2001

Relationship of the functional recovery after hip arthroplasty to the neuroendocrine and inflammatory responses.

We studied the relationship between the neuroendocrine and inflammatory responses to hip arthroplasty and functional recovery in 102 patients undergoing elective arthroplasty for osteoarthritis. Blood samples were collected for up to 7 days after surgery and analysed for concentrations of norepinephrine, epinephrine, cortisol, interleukin-6 and C-reactive protein. The primary outcome measures were milestones in hospital, times to walk 10 and 25 m, pain on discharge from hospital, and function 1 and 6 months after surgery. Walking distances in hospital were significantly delayed in patients with greater interleukin 6 and C-reactive protein concentrations, but few neuroendocrine measures had significant correlations with functional recovery in hospital. Multivariate analysis showed that the interleukin 6 concentration on day 1 was the unique predictor of time to walk 10 and 25 m, and that the day 2 concentration of C-reactive protein was the unique predictor of pain on discharge from hospital. No significant correlations were found between the inflammatory and neuroendocrine variables and recovery at 1 and 6 months. We conclude that the inflammatory response affects immediate functional recovery after hip arthroplasty.

Adult↗
PubMed2000

Comparison of 1% ropivacaine with 0.75% bupivacaine and 2% lidocaine for peribulbar anaesthesia.

We have compared the efficacy of 1% ropivacaine with a mixture of 0.75% bupivacaine and 2% lidocaine for peribulbar anaesthesia in cataract surgery. We used the time to adequate block for surgery, and ocular and eyelid movement scores at 8 min after block as clinical end-points. Ninety patients were allocated randomly to receive 7-10 ml of a mixture of equal parts of 0.75% bupivacaine and 2% lidocaine or an equal volume of 1% ropivacaine alone. Hyaluronidase 15 iu ml-1 was added to both solutions. There were no differences between groups in clinical end-points. Median time at which the block was adequate to start surgery was 8 min (interquartile range 4-10 min) in each group. Median eyelid movement scores were similar in both groups, but the bupivacaine and lidocaine mixture produced a significantly decreased ocular movement score at 2, 4 and 6 min (P < 0.05). There was no difference between groups in the incidence of minor complications. Based on clinical end-points, time to adequate block for surgery and median ocular and eyelid movement scores at 8 min, 1% ropivacaine as the sole agent for peribulbar anaesthesia was comparable with a mixture of 0.75% bupivacaine and 2% lidocaine.

Adult↗
PubMed2000

Existence of bistability and correlation with arrhythmogenesis in paced sheep atria.

INTRODUCTION: Studies of the electrical dynamics of cardiac tissue are important for understanding the mechanisms of arrhythmias. This study uses high-frequency pacing to investigate the dynamics of sheep atria. METHODS AND RESULTS: A 504-electrode mapping plaque was affixed to the right atrium in six sheep. Cathodal pacing stimuli were delivered to the center of the plaque. Pacing period (Tp) was decreased from 275 +/- 25 msec to 75 +/- 25 msec and then increased to 230 +/- 70 msec in steps of either 5 or 10 msec. In all 21 trials in six sheep, the atrium responded 1:1 at longer Tps and 2:1 at shorter Tps. As Tp was decreased, the response switched to 2:1 at a particular Tp. Conversely, as Tp was increased, the response switched back to 1:1 at a particular Tp. Over 21 trials, the 1:1-to-2:1 and 2:1-to-1:1 transitions occurred at 119.5 +/- 18.8 msec and 130.0 +/- 19.1 msec, respectively. This hysteretic behavior yielded bistability windows, 10.5 +/- 7.2 msec wide, wherein 1:1 and 2:1 responses existed at the same Tp. In 15 trials and in all animals, idiopathic wavefronts emanating from outside the mapped region passed through the mapped region. In 13 of those trials, the idiopathic wavefronts occurred at Tps within the bistability window or within 35 msec of its upper or lower limit. CONCLUSION: Bistability windows and idiopathic wavefronts were observed and found to be correlated with each other, suggesting a connection between bistability and arrhythmogenesis.

Animals↗
PubMed2000

Rapid methods for testing the efficacy of sterilization-grade filter membranes.

The validation of sterilization-grade membranes is integral to ensuring the efficient and safe use of microfiltration systems. Here validation refers to the production of sterile filtrate for sterilizing-grade membranes under challenge test conditions. Current validation methods require 48 h of culture for results to become available, which creates time delays within the manufacturing process and quality control (QC) backlogs. This work compares four methods for the production of filter challenge test data, to the desired test sensitivity, within 24 h using bioluminescent and fluorescent recombinant strains of the test organism Brevundimonas diminuta. These methods should provide a way to implement more rapid QC test regimens for filters.

Alphaproteobacteria↗
PubMed2000

Hip and knee arthroplasty: a comparison and the endocrine, metabolic and inflammatory responses.

Changes in circulating levels of catecholamines, cortisol, glucose, interleukin-6 and C-reactive protein and in the leucocyte count were investigated for 7 days after surgery in 158 patients undergoing hip or knee arthroplasty. We compared the responses to the two operations, and also examined the effects of pathology (osteoarthritis and rheumatoid arthritis) on the changes associated with knee arthroplasty. Exploratory factor analysis was applied to the data to identify the variables and sampling times that could be used in future to provide a concise description of the response. Patients undergoing knee arthroplasty showed significantly greater changes in noradrenaline, adrenaline and glucose levels, but not in cortisol levels, compared with those undergoing hip arthroplasty. Interleukin-6 and C-reactive protein concentrations were also significantly greater in knee patients than hip patients; however, when corrected for pathology, many of these differences were not significant. Minimal effects of pathology (chronic inflammation with rheumatoid arthritis) were found on the hormonal changes in knee patients. In particular, there was little evidence to support the inference from animal data that the hypothalamic-pituitary-adrenal axis is impaired. The expected increases in interleukin-6 and C-reactive protein concentrations were found in the rheumatoid arthritis patients. Exploratory factor analysis showed that the response could be separated into six components, accounting for 60% of the total variance, and identified the variables and sampling times indicative of each. In conclusion, there are differences in the hormonal, but not inflammatory, responses to hip and knee arthroplasty. Little evidence was found for an important effect of pathology on the changes associated with knee surgery. Factor analysis provided a useful summary of the data.

Aged↗
PubMed1999

Why do patients feel positive about patient-controlled analgesia?

We studied 200 patients to identify the aspects of their experience of patient-controlled analgesia (PCA) that made them feel 'extremely positive' about this technique. After PCA had been withdrawn, patients completed a questionnaire which included the following topics: pre-operative information, pain relief, the degree of control that PCA afforded the patient, side-effects and safety. Multiple regression analysis identified three factors of their experience which were associated uniquely with feeling 'extremely positive' about PCA: having better pain relief, not worrying about 'giving oneself too much drug' and not experiencing feeling 'peculiar in the head'. Control over pain relief, although highly correlated with feeling 'extremely positive' about PCA, was unimportant when these variables were controlled. Because of the well-recognised difficulties in measuring satisfaction with analgesic regimens, we suggest that a satisfaction score based on these variables would be a significant advance on existing methods.

Analgesia, Patient-Controlled↗
PubMed1999

The systematic assessment of short-term functional recovery after major joint arthroplasty.

Despite extensive information about long-term recovery from major joint arthroplasty, little attention has been given to the measurement of functional recovery in the immediate postoperative period. Therefore assumptions about the importance of physical therapy during this period remain untested. We devised a way of recording functional recovery before discharge, based primarily on the achievement of objective milestones. This was incorporated into routine physiotherapy practice and applied to sequential patients undergoing elective hip (n = 163) or knee (n = 66) replacement. Six months later, we followed up 160 patients, of whom 145 completed questionnaires to assess subjective physical and emotional state and functional recovery. The method was sensitive to known influences on pace of recovery, including type of arthroplasty (hip vs knee) and surgeons' differing requirements for mobilization. In addition, we were able to confirm and quantify sources of variation in functional recovery which previously were suspected but unconfirmed: in particular, the timing of early mobilization. Outcome at 6 months was unrelated to objective functional recovery in hospital, although fatigue and wellbeing at this time were predicted by physiotherapists' subjective assessment of patients' motivation before discharge. The findings can be used to inform patients and as a source of comparison data for the assessment of functional recovery in other centres. More importantly, the procedure reported may be applied to quantify functional recovery in routine practice and thereby expose variability in recovery to scientific scrutiny.

Aged↗
PubMed1999

Etomidate and the osteocalcin response to gynaecological surgery.

Circulating osteocalcin is a good marker of osteoblastic activity and decreases significantly after stressful physiological states such as major surgery. Glucocorticoids are known to inhibit osteoblastic activity and result in a decline in circulating osteocalcin. We used etomidate to inhibit the cortisol response to routine gynaecological surgery to determine if this would prevent the postoperative decline in osteocalcin. Twenty-four patients were allocated randomly to receive either thiopental or etomidate for induction of anaesthesia; all other aspects of anaesthesia and perioperative management were standardized. In the thiopental group, circulating cortisol increased significantly at 2 and 6 h after the start of surgery and plasma osteocalcin concentrations decreased significantly to almost 50% of baseline values at 48 h. Etomidate abolished the cortisol response to surgery, and circulating osteocalcin concentrations did not change after operation. There was a significant difference in osteocalcin concentration between the groups at 48 h. We conclude that the cortisol response to surgery is associated with a postoperative decrease in circulating osteocalcin.

Adult↗
PubMed1999

Diabetes mellitus and anaesthesia.

Diabetes mellitus is the most common endocrinological problem encountered by an anaesthetist and its prevalence will increase greatly in the next decade. This review focuses on the relevance of a new classification and diagnostic criteria for diabetes and the results of the important UK prospective diabetes study group trial. Other key areas of interest are the acute treatment of non-insulin-dependent diabetes (type 2), the management of coronary heart disease and vascular reactivity in patients with diabetes.

Journal Article↗
PubMed1998

Patients' reactions to attempts to increase passive or active coping with surgery.

It is generally regarded as valuable for patients to exercise control over aspects of their medical treatment. Although psychological and other interventions are commonly used with the aim of increasing patients' ability or willingness to control events, it is not known whether patients experience these procedures in the way assumed. The present study compared responses to (i) a psychological intervention designed to increase patients' readiness to exercise control and cope actively and (ii) a comparable intervention intended to induce acceptance and passive coping. Hip or knee arthroplasty patients were visited preoperatively by a researcher who administered the active (N = 15) or passive (N = 15) intervention in a dialogue with the patient. Patients' verbal responses to the interventions were analyzed qualitatively to identify the range of reactions to each type of intervention. Patients readily accepted the passive message on the grounds of doctors' and nurses' authority and the value of the patients' emotional detachment from their surgery. Few responses to the active message indicated acceptance that patients have control over their care and its outcomes; instead, recipients typically interpreted it in terms of the need for obedience to medical and nursing authority. In conclusion, patients do not automatically accept messages intended to change ways of coping. In particular, the attempt to increase patients' readiness to take control over aspects of care can be perceived by patients in an opposite way to that intended. This and previous studies suggest that patient control over aspects of treatment is a professional and theoretical construction that often means little to patients.

Adaptation, Psychological↗
PubMed1998

Patient-controlled analgesia: an assessment by 200 patients.

Two hundred patients completed a questionnaire about their experiences of patient-controlled analgesia. The questionnaire covered the following topics: pre-operative information, reasons for pressing and not pressing the button, pain relief, side-effects, safety, advantages and disadvantages of patient-controlled analgesia, worries associated with its use and control over pain. A high level of satisfaction with the device, together with a view that it afforded control over pain, emerged from replies to simple, general questions. However, more detailed questions revealed side-effects and fears that constrained its use and hence patients' ability to control pain. Control is predominantly a feature of the professional's view of patient-controlled analgesia, rather than the patient's experience of this analgesic technique.

Adolescent↗