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P Mitchell

Publications and source records attributed to P Mitchell.

At least 19 recordsLinked to original sources
PubMed2006

Side errors in neurosurgery.

Eight cases of neurosurgical operations being performed on the wrong side were studied. Safeguards of confidentiality were used. In seven cases side marking was not done and the surgeons felt that had it been done, the mistake would have or may have been prevented. In all but one case the surgeon's normal side check was omitted. Distracting circumstances contributed to the checks being omitted in these seven cases. In the one case where the check was carried out the mistake was made because the patient had been marked on the wrong side. In no case was the mistake made because of ambiguous or absent site data in the imaging or notes. It is concluded that to prevent these mistakes emphasis should be placed on ensuring that the preoperative site check is completed more than on ensuring that unambiguous side information is available in the notes and imaging.

Diagnostic Imaging↗
PubMed2006

Effect of primary-care spirometry on the diagnosis and management of COPD.

Primary-care spirometry has been promoted as a method of facilitating accurate diagnosis of chronic obstructive pulmonary disease (COPD). The present study examined whether improving rates of diagnosis lead to improvements in pharmacological and nonpharmacological management. From 1999 to 2003, the current authors provided an open-access spirometry and reversibility service to a local primary-care area, to which 1,508 subjects were referred. A total of 797 (53%) had pre-bronchodilator airflow obstruction (AFO). Of the subjects who underwent reversibility testing, 19.3% were no longer obstructed post-bronchodilator. The results and records of a subgroup of 235 subjects with post-bronchodilator AFO were examined. Of the 235 subjects, 130 received a new diagnosis, most commonly COPD. The patients with COPD were significantly undertreated before spirometry and testing led to a significant increase in the use of anticholinergics (37 versus 18%), long-acting beta-agonists (25 versus 8%) and inhaled steroids (71 versus 52%). More than three quarters of smokers received smoking cessation advice but very few were referred for pulmonary rehabilitation. In conclusion, primary-care spirometry not only increases rates of chronic obstructive pulmonary disease diagnosis, but it also leads to improvements in chronic obstructive pulmonary disease treatment. The use of bronchodilator reversibility testing in this setting may be important to avoid misdiagnosis.

Adult↗
PubMed2006

Retinal vascular calibre and the risk of coronary heart disease-related death.

OBJECTIVE: To examine whether retinal vascular calibre independently predicts risk of coronary heart disease (CHD) -related death. METHODS: In a population-based cohort study of 3654 Australians aged > or = 49 years, retinal arteriolar and venular calibres were measured from baseline retinal photographs and the arteriole to venule ratio (AVR) was calculated. CHD-related death was confirmed from the Australian National Death Index. RESULTS: Over nine years, 78 women (4.1%) and 114 men (7.8%) had incident CHD-related deaths. In people aged 49-75 years, wider venules were associated with CHD death, with relative risk (RR) 1.8 (95% confidence interval (CI) 1.1 to 2.7) and RR 2.0 (95% CI 1.1 to 3.6) per standard deviation (SD) increase in venular calibre for men and women, respectively, after adjustment for traditional risk factors. Additionally, in women aged 49-75 years, smaller AVR and narrower arterioles were associated with CHD death (RR 1.5, 95% CI 1.1 to 2.2, and RR 1.9, 95% CI 1.0 to 3.5 per SD decrease in AVR and arteriolar calibre, respectively, after adjustment). These associations were not observed in people aged > 75 years. CONCLUSIONS: These findings suggest that microvascular disease processes may have a role in CHD development in middle-aged people, particularly in women. Retinal photography may be useful in cardiovascular risk prediction.

Aged↗
PubMed2006

Lack of evidence of disease contamination in ovarian tissue harvested for cryopreservation from patients with Hodgkin lymphoma and analysis of factors predictive of oocyte yield.

Ovarian cryopreservation is a promising technique to preserve fertility in women with Hodgkin lymphoma (HL) treated with chemotherapy. Thus, the aim of this study was to examine harvested ovarian tissue for subclinical involvement by HL by morphology/immunohistochemistry, and to define patient and treatment factors predictive of oocyte yield. This was a retrospective analysis of 26 ovarian tissue samples harvested for cryopreservation from women with HL. Histology, immunohistochemistry and follicle density (number mm(-3)) was examined. Disease status and preharvest chemotherapy details were obtained on 24 patients. The median age was 22 years (range 13-29). Seven of 24 patients had infradiaphragmatic disease at time of harvest. Nine of 20 patients had received chemotherapy preharvest (ABVD (Adriamycin), Bleomycin, Vinblastine and Dacarbazine) = 7, other regimens = 2). The seven receiving ABVD showed no difference in follicle density compared to patients not receiving treatment (n = 14); (median = 1555 vs 1620 mm3 P = 0.97). Follicle density measurement showed no correlation with patient age (R2 = 0.0001, P = 0.99). There was no evidence of HL involvement in the 26 samples examined (95% CI = 0-11%). In conclusion, subclinical involvement of HL has not been identified in ovarian tissue, even when patients have infradiaphragmatic disease. Furthermore, the quality of tissue harvested does not appear to be adversely affected by patient's age or prior ABVD chemotherapy.

Adolescent↗
PubMed2006

Early age-related maculopathy in eyes after cataract surgery.

PURPOSE: To assess age-related maculopathy (ARM) in eyes of patients who had undergone cataract surgery for at least a year. METHODS: Consecutive patients aged 60+ years who had undergone cataract surgery at Westmead Hospital, Sydney, Australia, during 2001-2003 were examined in 2004. Interview using standardized questionnaires and stereo retinal photography was performed. Retinal photographs were graded using the Wisconsin ARM grading system. The proportions with ARM were compared between surgical and nonsurgical eyes, and between this surgical cohort and the Blue Mountains Eye Study (BMES) population. RESULTS: Of the 622 eligible patients, 454 (73%) were re-examined, with a mean follow-period of 2.8 years. Surgical eyes had a higher proportion of early ARM compared to nonsurgical eyes (15.2 vs10.3%, P=0.07) and to the early ARM prevalence found in BMES participants of similar age (14.5 vs6.9%, P<0.01), which persisted after age standardization to the BMES population (9.7 vs6.9%, P<0.05). CONCLUSIONS: We found an increased prevalence of early ARM in surgical eyes of patients 1-3 years after cataract surgery. Whether this increased early ARM prevalence leads to an increased prevalence of late ARM in the long-term warrants further investigation.

Aged↗
PubMed2006

The significance of crossovers after randomization in the STICH trial.

INTRODUCTION: Of all forms of stroke, spontaneous intracerebral haemorrhage (ICH) causes the highest morbidity and mortality. The Surgical Trial in Intracerebral Haemorrhage (STICH) found no difference in outcomes between patients randomized to surgical or conservative treatment. PATIENTS AND METHODS: Of 530 patients randomized to initial conservative treatment, 140 crossed over to surgery. This study examines the variables associated with crossover. RESULTS: Dominant features of the crossover group were: male, (p = 0.04), right-sided clot (p = 0.03), lobar clot (p = 0.003), clot volume (median 64 mL for crossovers vs. 38 mL for others, p < 0.00001), midline shift (median 6 mm for crossovers vs. 3 mm for others, p < 0.00001), superficial clot (median 1.3 mm for crossovers vs. 11.5 mm for others, p < 0.00001), and randomization within 12 hours of ictus (p < 0.0005). Thalamic location (p = 0.002) was under-represented. Intraventricular haemorrhage, hydrocephalus, and focal deficits were not associated with crossover. Craniotomy was the method of evacuation in 85% of crossover patients. CONCLUSIONS: Crossover to surgery was more likely when ICH had these features: Right side, lobar location, superficial, large volume, big shift, and early randomization. Crossovers formed a worse prognostic group compared to non-crossovers. Surgery did not affect trial results, which were analyzed by intention-to-treat.

Bias↗
PubMed2006

Decompressive craniectomy in traumatic brain injury: the randomized multicenter RESCUEicp study (www.RESCUEicp.com).

The RESCUEicp (Randomized Evaluation of Surgery with Craniectomy for Uncontrollable Elevation of intracranial pressure) study has been established to determine whether decompressive craniectomy has a role in the management of patients with traumatic brain injury and raised intracranial pressure that does not respond to initial treatment measures. We describe the concept of decompressive craniectomy in traumatic brain injury and the rationale and protocol of the RESCUEicp study.

Biomedical Research↗
PubMed2006

In-vivo measurement of brain relaxation after lobectomies.

Very little data exists on the visco-elastic properties of the living human brain tissue and collection of such data is vital for mechanical modelling. The purpose of this study was to measure the rate of relaxation of brain that has been compressed by tumour after surgical decompression. Seven patients who underwent a lobectomy for an intracranial space occupying lesion were included in the study. All underwent two CT scans within the first 24 h after the surgery. Volumes of the residual void on the serial CT scan were calculated using tools in the image acquisition software. There was a rapid expansion of the brain to fill up the void space in the first 24 h after surgery. The average rate of relaxation of the compressed brain is 2.25(0.76 - 6.64) ml/h. The graphs plotted for the volume of the void space against the time after surgery when the CT scans were done can be used to further explore the dynamics of brain relaxation. The rate of brain relaxation in the first 24 h after removal of a mass lesion averages 2.25(0.76 - 6.64) ml/h in this study. Further studies using more frequent data collection would allow for more accurate definition of the rate of relaxation.

Aged↗
PubMed2006

Actions taken to cope with depression in patients seeking specialist care.

OBJECTIVE: To assess the rates and perceived effectiveness of actions used to cope with depression and the factors influencing these in an outpatient sample seeking help for depression. METHOD: One hundred and seventy-six patients (74 male, 102 female) aged 16-82 years (M = 42, SD = 14.4 years) with a major depressive episode (DSM-IV criteria) were assessed using a number of measures that covered sociodemographics, history of psychiatric illness, actions taken to alleviate depression and their perceived effectiveness. Logistic regression analyses assessed age, gender and illness characteristics associated with the use and perceived effectiveness of strategies adopted to manage depression. RESULTS: Medical interventions were used and perceived to be effective in alleviating depressive symptoms by most of the sample, as were self-help and complementary therapies. Sociodemographic and illness-related characteristics had a significant influence, with younger age and having experienced an episode of anxiety disorder found to be the strongest predictors for the use of coping strategies. Being female was the strongest predictor for their effectiveness. CONCLUSION: A range of actions for depression, including medical and complementary interventions, were used and found to be helpful in a sample that had sought professional help for depression. Gender, age, depression and anxiety factors were all found to predict the use and perceived effectiveness of these strategies.

Adaptation, Psychological↗
PubMed2006

Prevalence of mitochondrial DNA haplogroups in an Australian population.

Mitochondrial DNA (mtDNA) haplogroups are 'neutral polymorphisms' in the mtDNA genome, which have accumulated and persisted along maternal lineages as the human population has migrated worldwide. Three ethnically distinct lineages of human mtDNA populations have been identified: European, characterized by nine haplogroups H, I, J, K, T, U, V, W and X; African, characterized by superhaplogroup L and Asian, characterized by superhaplogroup M. We studied the prevalence of mtDNA haplogroups in participants of the Blue Mountains Eye Study, a large population-based survey of vision conducted between 1991 and 2000 of non-institutionalized permanent residents aged 49 years or older from two suburban postcode areas, west of Sydney, Australia. Total DNA isolated from either hair follicles or blood was available for 3377 of the 3509 participants (96.2%) to determine mtDNA haplogroups by polymerase chain reaction/restriction fragment length polymorphism analysis. Approximately 94.2% of samples could be assigned to one of the nine major European haplogroups, whereas a further 1.2% included the African (L) and Asian (M) superhaplogroups. The five principal haplogroups represented were H (42.9%), U (14.1%), J (10.7%), T (9.2%) and K (8.1%), which together included 85% of this population.

DNA, Mitochondrial↗
PubMed2006

Prevalence and associations of anisometropia and aniso-astigmatism in a population based sample of 6 year old children.

AIM: To study the distribution of anisometropia and aniso-astigmatism in young Australian children, together with clinical and ocular biometry relations. METHOD: The Sydney Myopia Study examined 1765 predominantly 6 year old children from 34 randomly selected Sydney schools during 2003-4. Keratometry, cycloplegic autorefraction, and questionnaire data were collected. RESULTS: Spherical equivalent (SE) anisometropia (> or =1 dioptre) prevalence was 1.6% (95% confidence interval (CI) 1.1% to 2.4%). Aniso-astigmatism (>or =1D) prevalence was 1.0% (CI: 0.6% to 1.6%). Both conditions were significantly more prevalent among moderately hyperopic (SE > or =2.0D) than mildly hyperopic (SE 0.5-1.9D) children. Myopic children (SE < or =-0.5D) had higher anisometropia prevalence. Neither condition varied by age, sex, or ethnicity. In multivariate analyses, anisometropia was significantly associated with amblyopia, odds ratio (OR) 29, (CI: 8.7 to 99), exotropia (OR 7.7, CI: 1.2 to 50), and neonatal intensive care unit (NICU) admission (OR 3.6, CI: 1.1 to 12.6). Aniso-astigmatism was significantly associated with amblyopia (OR 8.2, CI: 1.4 to 47), maternal age >35 years (OR 4.0, CI: 1.3 to 11.9), and NICU admission (OR 4.6, CI: 1.2 to 17.2). Anisometropia resulted from relatively large interocular differences in axial length (p<0.0001) and anterior chamber depth (p = 0.0009). Aniso-astigmatism resulted from differences in corneal astigmatism (p<0.0001). CONCLUSION: In this predominantly 6 year old population, anisometropia and aniso-astigmatism were uncommon, had important birth and biometry associations, and were strongly related to amblyopia and strabismus.

Amblyopia↗
PubMed2006

Impaired cerebral autoregulation and 6-month outcome in children with severe traumatic brain injury: preliminary findings.

The objective of this study was to describe the incidence of impaired cerebral autoregulation and to describe the relationship between impaired cerebral autoregulation and outcome after severe pediatric traumatic brain injury (TBI). We prospectively examined cerebral autoregulation in 28 children<or=17 (10+/-5) years with a Glasgow coma scale score<9 within the first 72 h of pediatric intensive care unit admission. Children with isolated focal TBI were excluded. Glasgow outcome scores (GOS) were collected at hospital discharge, as well as 3 and 6 months after severe TBI. GOS<4 reflected poor outcome. Cerebral autoregulation was impaired in 12/28 children. An autoregulatory index<0.4 was associated with GOS<4 at 6 months (p=0.005). Impaired cerebral autoregulation, early after severe pediatric TBI, was associated with a poor 6-month outcome.

Adolescent↗
PubMed2006

An overview of the prevalence of 25-hydroxy-vitamin D inadequacy amongst elderly patients with or without fragility fracture in the United Kingdom.

BACKGROUND: Many studies have investigated the prevalence of 25-hydroxy-vitamin D inadequacy throughout the world and found a high prevalence of 25-hydroxy-vitamin D inadequacy in older patients, particularly those with fragility fracture. SCOPE: To review the findings from vitamin D audits from six units across the UK and compare with previously published data from around the world. Results from four units have been previously published (Belfast, Glasgow, London and Medway) and this paper presents new data from Southampton and Carshalton, and further sub-analysis of the data from Medway. FINDINGS: Three audits of patients attending metabolic bone clinics (Carshalton, Medway and Southampton) identified 954 patients, of which overall 49% had a prior fragility fracture. Mean 25-hydroxy-vitamin D levels ranged from 47.7 nmol/L to 62.4 nmol/L. Of these patients 72.9-88.9% had a 25-hydroxy-vitamin D level < 80 nmol/L, 68.8-83.3% < 70 nmol/L and 37.5-59.1% < 50 nmol/L. The mean age of patients ranged from 60.0 to 67.5 years. Sub-analysis of the data by fracture status revealed that patients with fracture had lower mean levels of 25-hydroxy-vitamin D compared with patients without fracture. This was statistically significant in the sub-analysis of the Medway data (45.3 nmol/L versus 49.9 nmol/L, p < 0.005). Three audits identified 330 patients with fragility fracture. Audits from Glasgow and Belfast specifically identified patients with fragility fracture. A subgroup of patients with fracture aged over 50 years from the Medway audit was also included in this group. Mean levels of 25-hydroxy-vitamin D ranged from 40.0 nmol/L to 52.3 nmol/L. 83.7-96.4% of patients had a 25-hydroxy-vitamin D level < 80 nmol/L, 73.3-89.7% < 70 nmol/L and 55.8-73.2% < 50 nmol/L. The mean age of patients ranged from 65.3 to 68.6 years. The audits carried out in Belfast and Medway were also divided by supplementation status. Mean 25-hydroxy-vitamin D levels were 48.1 nmol/L in Belfast and 40.5 nmol/L in Medway in the patients not receiving supplements and 53.8 nmol/L and 59.9 nmol/L, respectively in the patients receiving supplements. The difference was statistically significant in the Medway audit (p < 0.0001), but not in the smaller Belfast audit (p = 0.216). As would be expected, the prevalence of 25-hydroxy-vitamin D inadequacy was higher in the patients not receiving supplements, for example at the 70 nmol/L threshold: 82.6% versus 67.1% in Belfast and 89.6% versus 72.7% in Medway. Three audits specifically identified 694 patients with hip fracture (Belfast, Glasgow and London). Mean levels of 25-hydroxy-vitamin D ranged from 24.7 nmol/L to 36.1 nmol/L. Of these patients 90.7-99.0% had a 25-hydroxy-vitamin D level < 80 nmol/L, 88.4-98.0% < 70 nmol/L and 81.6-92.7% < 50 nmol/L. The mean age of patients ranged from 73.4 to 80.5 years. CONCLUSION: Inadequate 25-hydroxy-vitamin D levels are extremely common in the elderly and particularly so in patients with fragility fracture - specifically in those with hip fracture. Although the differing audit specifications and assay techniques used make direct comparisons difficult, the data do provide a snapshot of 25-hydroxy-vitamin D status across the UK and are consistent with those previously observed elsewhere in Europe and the rest of the world.

Aged↗
PubMed2005

Age-related maculopathy and cataract surgery outcomes: visual acuity and health-related quality of life.

PURPOSE: To assess visual acuity (VA) and health-related quality of life (HRQoL) outcomes in patients with and without age-related maculopathy (ARM) after cataract surgery. METHODS: Patients aged 60+ years who had undergone cataract surgery at the Westmead Hospital during 2001-2003 were re-examined 1-3 years after surgery. Tests included VA and assessment of visual- and HRQoL using standardised questionnaires (VF-14, SF-12). Preoperative comorbidity data were collected from medical records. Poor surgical outcomes (VA<6/12; no VA improvement; lowest quintile of VF-14, SF-12 scores) were compared in patients with and without ARM, adjusting for age, sex, preoperative systemic comorbidities, ocular comorbidities and surgical or postoperative complications. RESULTS: Of 622 surviving patients, 454 (73%) were followed up for a mean period of 2.8 years. Similar proportions with VA>or=6/12 were observed in patients with (80.2%) and without (88.8%) pre-existing ARM. Preoperative early ARM was only associated with slightly lower mean VF-14 scores (87.64 with vs 92.58 without ARM, P=0.01). Increasing age and preoperative ocular comorbidities were associated with all poor outcomes measured. Low SF-12 scores were associated with preoperative systemic comorbidities. CONCLUSION: Our study documents favourable cataract surgical outcomes 1-3 years after cataract surgery in patients with preoperative ARM.

Aged↗
PubMed2005

Retinal microvascular signs and risk of stroke and stroke mortality.

OBJECTIVE: The purpose of this study was to assess the relation of retinal microvascular signs and incident stroke and stroke mortality in an older population. METHODS: The authors took retinal photographs on baseline participants (3,654 patients aged 49+ years) of the Blue Mountains Eye Study (1992 to 1994). They assessed the presence of retinopathy (microaneurysms, retinal hemorrhages) in participants without diabetes and retinal arteriolar signs in all participants using standardized grading protocols. Incident stroke/TIA/cerebrovascular death (combined stroke events) were identified at follow-up examinations during 1997 to 1999. RESULTS: During a 7-year period, 859 participants died, 97 (11.3%) of which died of cerebrovascular causes. Of survivors, 24 had confirmed incident stroke, and 11 had incident TIA. Combined stroke events were more frequent in participants with retinopathy (5.7%), with moderate/severe arteriovenous nicking (4.2%), or with focal arteriolar narrowing (7.2%) compared with those without (1.9%). After controlling for age, sex, systolic blood pressure, smoking, and self-rated health, retinopathy was significantly associated with combined stroke events (relative risk [RR] 1.7, 95% CI 1.0 to 2.8) in persons without diabetes. This association was stronger in those without severe hypertension (RR 2.7, CI 1.2 to 6.2) or in persons with two or more retinal microvascular signs (RR 2.7, CI 1.5 to 5.2). Generalized or focal arteriolar narrowing or arteriovenous nicking was not independently associated with combined stroke events after multivariate adjustment. CONCLUSIONS: In older Australians without diabetes, retinopathy signs predict stroke or stroke-related death independent of traditional stroke risk factors.

Age Factors↗