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Biomedical subjects

K W Lindsay

Publications and source records attributed to K W Lindsay.

At least 19 recordsLinked to original sources

Continuing education: the British experience.

The methods used to assess proficiency in neurosurgical trainees and consultant staff are reviewed. Under the auspice of the Surgical Royal Colleges trainees undergo a formal assessment 6 monthly by their trainer, annually by a local training committee and in their 3rd year of training by the Specialist Advisory Committee (SAC) in Neurosurgery. This committee supervises all neurosurgical training in the UK and Ireland and recommends trainees for the Certificate of Completion of Training if their training assessments and operative experience are satisfactory and if they have passed the Intercollegiate Specialty Examination in Neurosurgery. Assessing proficiency of consultant staff in the UK poses greater difficulty. For several years neurosurgeons have registered Continuing Medical Education (CME) credits on a voluntary basis. Such action is insufficient to reassure the public of professional competence. The General Medical Council (GMC) have submitted proposals for revalidation based on- (i) the maintenance of a 'folder' including details of performance, CME and complaints, (ii) annual appraisals carried out internally, (iii) a 5 yearly external assessment which if satisfactory would lead to revalidation by the GMC. Team working will be encouraged and consultants made responsible for the quality of service of their professional colleagues. A national comparative audit of subarachnoid haemorrhage should permit comparison of outcomes between neurosurgical units.

Clinical Competence↗

Definition of initial grading, specific events, and overall outcome in patients with aneurysmal subarachnoid hemorrhage. A survey.

BACKGROUND AND PURPOSE: Scientific communication in medicine can be effective only if reports are based on unequivocal criteria for clinical conditions or specific diagnoses. METHODS: We reviewed all articles about subarachnoid hemorrhage published in nine neurosurgical or neurological journals from 1985 through 1992 and assessed the presence and the precision of definitions used for reporting the initial grade, the specific complications of rebleeding, delayed cerebral ischemia, and hydrocephalus, and the overall outcome. We identified 184 articles reporting direct observations in at least 10 patients on one or more of these conditions. RESULTS: Of 161 articles reporting the initial condition, only 19% used an unequivocal grading system (World Federation of Neurological Surgeons Scale or Glasgow Coma Scale); this proportion did not increase after 1988, when the World Federation of Neurological Surgeons Scale was introduced. The specific outcome events of rebleeding, ischemia, and hydrocephalus (283 instances) were sufficiently defined in only 31% of instances, incompletely in 22%, and not at all in 47%. The proportions were similar when the results were analyzed according to the type of complication, the year of publication, or per study. The four exclusively neurosurgical journals featured suitable definitions for any of the three outcome events in 20% of 209 instances, whereas the five mainly neurological journals published fewer articles about subarachnoid hemorrhage (74 instances of outcome events) but more often with precise criteria (65%). Overall outcome was adequately reported in 63% of all articles, with an increase over the years (54% in 1985 through 1988, 71% in 1989 through 1992). CONCLUSIONS: Reports about subarachnoid hemorrhage require closer scrutiny before publication to ascertain whether the conclusions about specific outcome events are based on unequivocal criteria.

Bias↗

Amount of blood on computed tomography as an independent predictor after aneurysm rupture.

BACKGROUND AND PURPOSE: After admission to the hospital of patients with aneurysmal subarachnoid hemorrhage, we assessed the predictive value of the extent of the hemorrhage on computed tomography in addition to that of clinical grading scales for poor outcome, infarction, and rebleeding. METHODS: We studied 471 consecutive patients with aneurysmal subarachnoid hemorrhage and used logistic regression with step-wise forward selection of variables. RESULTS: On admission, poor outcome was predicted by a low Glasgow Coma Scale score (odds ratio, 0.8; 95% confidence interval, 0.7-0.9); treatment with fluid restriction (2.5; 1.6-4.0); age over 52 (2.6; 1.7-3.9); loss of consciousness at ictus (1.7; 1.1-2.6); or a large amount of subarachnoid blood (2.0; 1.3-3.1). Delayed infarction was predicted by a large amount of subarachnoid blood (1.8; 1.2-2.6) or treatment with tranexamic acid (1.6; 1.1-2.4). Rebleeding was predicted by treatment with tranexamic acid (0.4; 0.3-0.7; protective effect); age over 52 (1.9; 1.2-3.0); loss of consciousness at ictus (1.7; 1.1-2.7); or admission to a neurosurgery service (0.6; 0.3-0.9; protective effect). Comparison of the observed and predicted outcome events showed that inclusion of the amount of subarachnoid blood into a predictive model added little to the prediction of poor outcome in general, but much to the prediction of delayed cerebral ischemia. CONCLUSIONS: The total amount of subarachnoid blood on the initial computed tomogram has independent predictive power for the occurrence of delayed cerebral ischemia.

Age Factors↗

Treatment of acute hydrocephalus after subarachnoid hemorrhage with serial lumbar puncture.

Computed tomography demonstrated acute hydrocephalus less than or equal to 72 hours after subarachnoid hemorrhage in 24 (23%) of 104 patients. Of these 24 patients, six (25%) had no impairment of consciousness. In nine (11%) of the remaining 80 patients, acute hydrocephalus developed within 1 week after subarachnoid hemorrhage. With the exception of three patients, all 104 patients received antifibrinolytic treatment. Delayed clinical deterioration from acute hydrocephalus occurred in seven (29%) of the 24 patients with acute hydrocephalus on admission and in six (8%) of the remaining 80 patients. Serial lumbar puncture was performed in 17 patients. Twelve (71%) of the 17 patients treated with serial lumbar puncture, including 10 (77%) of the 13 patients with delayed deterioration from acute hydrocephalus after admission, achieved improvement in the level of consciousness. Four of these 17 patients (4% of all 104 patients) required an internal shunt. No patient deteriorated from coning following serial lumbar puncture. The rebleeding rate within 12 days after subarachnoid hemorrhage in hydrocephalic patients with serial lumbar puncture was not higher than the rate in those without hydrocephalus (two [12%] of 17 versus nine [13%] of 71). Neither meningitis nor ventriculitis was observed. We conclude that if neither a hematoma with a mass effect nor an obstructive element exists, cerebrospinal fluid drainage with serial lumbar puncture is a good alternative to ventricular drainage in patients with acute hydrocephalus after subarachnoid hemorrhage.

Acute Disease↗

Computed tomography in the diagnosis of malignant brain tumours: do all patients require biopsy?

A proportion of patients with computed tomographic (CT) scan appearances of malignant brain tumour undergo conservative management, despite the absence of histological confirmation of the diagnosis. Concern that this policy risked misdiagnosing a benign tumour prompted us to examine the accuracy of CT scanning in diagnosing malignant lesions. The study was designed to determine whether within a group of 300 patients with intracerebral mass lesions of known pathology, two sub-groups existed: one with appearances so specific for malignant glioma that biopsy was unnecessary, and the other in which the appearances were characteristic of malignancy, though not specific for glioma. Three neuroradiologists independently reviewed the CT scans, together with brief clinical details. When diagnosing malignant tumours, all made errors: nine benign lesions were considered to be malignant. When diagnosing malignant glioma, one neuroradiologist made errors, but the other two adopted a more cautious approach and were accurate. The restricted a "certain" diagnosis to about one in five scans considered to show malignant tumour. Those diagnosed specifically as malignant glioma were intrinsic, irregular, mixed density lesions, exhibiting variable enhancement and infiltrating the peri-ventricular tissues, especially the corpus callosum. Using these criteria, they could correctly identify a small proportion of patients with malignant gliomas. In all other patients, biopsy remains the only means of obtaining a definitive diagnosis.

Biopsy↗

Short-term tranexamic acid treatment in aneurysmal subarachnoid hemorrhage.

Antifibrinolytic treatment for 4 weeks after a subarachnoid hemorrhage has been shown to have no effect on outcome since a reduction in the rate of rebleeding was offset by an increase in ischemic events. To determine if a shorter course (4 days) of antifibrinolytic treatment before the expected onset of ischemic complications might reduce the rate of rebleeding yet avoid ischemic complications, we prospectively studied a series of 119 patients with subarachnoid hemorrhage; 479 patients with subarachnoid hemorrhage from our previous randomized double-blind study (238 treated with placebo, 241 with long-term tranexamic acid) served as historical control groups. At 3 months' follow-up, the outcome of patients treated with short-term tranexamic acid was not different from that of patients treated with long-term tranexamic acid. The rate of rebleeding (24 of 119, 20%) was near that with placebo (56 of 238, 24%). In contrast, the rate of cerebral infarction (33 of 119, 28%) was almost identical to that after long-term tranexamic acid (59 of 241, 24%), although mortality from cerebral infarction was reduced. Compared with historical control groups, treatment with tranexamic acid for 4 days fails to reduce the incidence of rebleeding but still increases the rate of cerebral infarction.

Cerebral Angiography↗

Effect of fludrocortisone acetate in patients with subarachnoid hemorrhage.

In this study with randomized controls, we administered fludrocortisone acetate to 46 of 91 patients with subarachnoid hemorrhage in an attempt to prevent excessive natriuresis and plasma volume depletion. Fludrocortisone significantly reduced the frequency of a negative sodium balance during the first 6 days (from 63% to 38%, p = 0.041). A negative sodium balance was significantly correlated with decreased plasma volume during both the first 6 days (p = 0.014) and during the entire 12-day study period (p = 0.004). Although fludrocortisone treatment tended to diminish the decrease in plasma volume, the difference was not significant (p = 0.188). More patients in the control group developed cerebral ischemia (31% vs. 22%) and, consequently, more control patients were treated with plasma volume expanders (24% vs. 15%), which may have masked the effects of fludrocortisone on plasma volume. Fludrocortisone therefore reduces natriuresis and remains of possible therapeutic benefit in the prevention of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Clinical Trials as Topic↗

Outcome of aneurysmal subarachnoid hemorrhage in patients 66 years of age and older.

The outcome at three months after aneurysmal SAH in a group of older patients and a group of younger patients is compared. The patients were admitted within 72 hours of their SAH. Of 61 patients 66 years of age and older, comprising 13% of the whole patient group, 52% died, 12% remained dependent and 36% became independent. In the younger group, 55% had an independent outcome (p less than 0.01). In contrast to what we expected in the older patient group, not extracranial, but intracranial events (re-bleeds, infarcts, hydrocephalus) were by far the most frequent cause of deterioration.

Age Factors↗

Antifibrinolytic agents in subarachnoid haemorrhage.

For many years clinicians have used antifibrinolytic agents to try to reduce rebleeding after subarachnoid haemorrhage. Early studies of their effectiveness produced conflicting results. This paper re-evaluates the available trials and considers benefits in the light of potential complications. Present evidence conclusively demonstrates that epsilon-aminocaproic acid and tranexamic acid administered in standard dosage, reduce the risk of rebleeding but, as a result of an increased incidence of ischaemic complications, do not benefit patients' outcome.

Antifibrinolytic Agents↗

Differences in the management of ruptured intracranial aneurysms: a survey of practice amongst British neurosurgeons.

British consultant neurosurgeons in post for at least one year were sent a postal questionnaire about the way in which they managed patients with ruptured aneurysms; 87% replied. Wide differences were evident in almost all aspects of treatment, before, during and after surgery. A consensus of opinion appeared in only a few areas: the employment of magnification during surgery, the use of clipping as the preferred method of surgical treatment, and a general reluctance to operate on patients with a depressed conscious level within a week of haemorrhage.

Age Factors↗

Distant extradural haematoma complicating removal of frontal tumours.

The authors report two patients who developed occipito-parietal extradural haematomas following removal of large frontal meningiomas. In both, CT scanning aided diagnosis and subsequent management. Although rare, this complication should be considered when patients deteriorate or fail to improve after removal of frontally situated tumours or inexplicable brain swelling is encountered at the time of original surgery.

Adult↗