PubMed Health⌕ Search

Biomedical subjects

L Brock

Publications and source records attributed to L Brock.

At least 19 recordsLinked to original sources
PubMed1996

Observer variation in the interpretation of intra-arterial angiograms and the risk of inappropriate decisions about carotid endarterectomy.

OBJECTIVE: To determine how often observer variation in the interpretation of intra-arterial angiograms might alter the decision whether or not to refer patients for carotid surgery. METHODS: A prospective study was carried out in a consecutive series of 99 patients with transient ischaemic attacks and minor strokes. Interpretable angiographic films were available for 179 carotid artery bifurcations. Stenosis of the internal carotid artery was measured using mm scales, independently by three different radiologists (A, B, and C), using the European Carotid Surgery Trial method. RESULTS: An analysis of the grouped data showed good to moderate agreement by kappa statistics for radiologists A v B, B v C, and A v C of 0.68, 0.60, and 0.70 respectively. The mean absolute difference in the estimate of stenosis by each of the different radiologists (interobserver variation) was 9.5% and for each radiologist on two separate occasions (intraobserver variation) 8.4%. The degree of observer error was smallest among severely stenosed arteries. Although the absolute differences were small, "clinically important" differences which could change the treatment recommended from surgery to no surgery (or vice versa) occurred between radiologists A and B, B and C, and A and C in: seven (3.9%), six (3.4%), and 11 (6.1%) vessels respectively. CONCLUSIONS: Because observer variation affects all of the imaging methods (Doppler, duplex, contrast arteriography, and MR angiography) used to select patients with transient ischaemic attack and stroke, these findings are likely to be widely relevant. Any centre assessing patients with cerebrovascular disease will need to implement strict quality control measures in the interpretation of angiograms (and other vascular imaging procedures) to minimise observer error and thereby reduce the number of inappropriate decisions made to refer for carotid artery surgery or not.

Carotid Artery Diseases↗
PubMed1995

The incidence of first Hickman catheter-related infection and predictors of catheter removal in cancer patients.

OBJECTIVE: To describe the incidence and types of first Hickman catheter-related infection (HCRI) in cancer patients and to identify indicators for catheter removal. DESIGN: Retrospective cohort study. SETTING: A regional, tertiary, referral cancer center and its supportive care university teaching hospital. PATIENTS AND METHODS: A retrospective review was conducted of 316 consecutive adult oncology patients who underwent Hickman catheter placement from 1986 to 1990 at a regional oncology center. HCRI was determined on the basis of clinical information incriminating the Hickman catheter as the source of infection. Patient characteristics and data about HCRIs (exit site cellulitis, tunnel infection with concomitant exit site cellulitis, bloodstream infection, and exit site cellulitis with bloodstream infection) were abstracted from patient medical records. Subsequently, univariate and multivariate analyses for the risk of HCRI and catheter removal were completed. RESULTS: The incidence of first HCRI was 5.98 infections per 1,000 catheter days. Overall, 156 (49%) of 316 patients developed their first HCRI prior to catheter removal. The median time to HCRI was 90 days. Male gender (P = .0004) and hematologic malignancy (P = .0001) emerged as significant risk factors for HCRI in the univariate analysis. A cox model verified that male gender (P = .02) and hematologic malignancy (P = .004) were associated with an enhanced risk of HCRI. There were 35 exit site infections (23%), three infections of the tunnel and the exit site (2%), 80 bloodstream infections (51%), and another 38 bloodstream infections with concomitant exist site infections (24%). The incidence of bloodstream infection was 3.05 per 1,000 catheter days. Gram-positive pathogens outnumbered gram-negatives and fungi, with Staphylococcus epidermidis being most common. Fifty (32%) of 156 HCRIs resulted in catheter removal. Predictors of Hickman catheter removal in the univariate analysis were bloodstream infection (P = .046) and pathogen type (P = .006). Multiple regression analysis suggested that having a gram-negative (P = .014) or fungal (P = .057) pathogen was the most important factor for catheter removal. CONCLUSIONS: These data suggest that first HCRIs occur more commonly in male patients with hematologic malignancies than in patients with solid tumors. The removal of Hickman catheters in oncology patients probably is predicated on the causative pathogen, but further investigations are necessary to delineate this issue.

Adult↗
PubMed1980

Retention of wooden foreign bodies in the orbit.

Two cases of retention of wooden foreign bodies in the orbit are presented. Both patients had a draining fistula. A brain abscess developed in one and a foreign body granuloma in the other. In both cases computerized tomography was very helpful in localizing the foreign bodies and the sequelae. In such cases a subperiosteal surgical approach provides good exposure and minimizes the damage to the orbital contents. A high degree of suspicion of penetration of the orbit is essential in tree branch injuries of the eyelids.

Adult↗
PubMed1975

The importance of environmental conditions, especially temperature, in the operating room and intensive care ward.

Although most patients are essentially well enough to be able to resist or to adapt to unfavourable ambient conditions, this may not be so with an ill patient or one who is having or has had a serious operation. The climatic conditions necessary in the operating room to give an optimal environment are discussed. These are second in importance only to control of infectivity. Air-conditioning in operating suites should be obligatory; there is even official acceptance of this. Earlier recommendations that the operating room should be heated to up to 80 degree F (27-9 degree C) are obsolete. The temperature most favoured by surgeons is 18-5-21 degree C; some prefer a range of 21-22 degre C. The critical ambient temperature desirable is 21 degree C. For infants and children this may be increased up to 24 degree C. It is difficult or impossible to achieve climatic conditions in the operating room that are acceptable to all. The needs of the patient are of special importance and are largely neglected; he alone is unable to speak for himself. The disposition of air inlets in the operating room is fully discussed. Climatic conditions in the intensive care unit are of great importance and are discussed. The need for full air-conditioning is absolute although this is often ignored. The delivery of conditioned air within the intensive care unit is also fully presented, especially the need to avoid direct chilling of the patient. The advantages of horizontal laminar air flow are presented.

Air Conditioning↗
PubMed1975

Observations on peripheral and central temperatures with particular reference to the occurrence of vasoconstriction.

The importance is emphasized of the inadequacy of the term 'body temperature', but that both core temperature and the peripheral temperature must be considered. The assessment of vasoconstriction is informative, and advantage should be taken of the exact information that can be provided by an electro-thermometer as opposed, for example, to a touch of the hand. The core temperature is taken from the rectum, the nasopharynx or tympanic membrane, and the peripheral temperature from the great toe. If the peripheral temperature falls the loss of body heat is prevented and the core temperature rises. If this is not understood or not recognized misguided attempts may be made to try to reduce the raised central temperature by cooling the skin. This can result in a further rise of central temperature. The recognition of peripheral vasoconstriction enables a proper assessment to be made of its basic cause and of the necessary treatment. The most important cause is hypovolaemia from blood loss and a detailed account is given of how this should be recognized, especially by a study of the gradient between central and peripheral temperatures. Such studies should be a routine in any severe illness, whether medical or surgical, in which circulatory deterioration is likely, especially after major operations or injuries. Study of the temperature of the heel (hindfoot) as well as of the toe (forefoot) can indicate a selective shutdown of peripheral circulation that reveals an especially critical circulatory state.

Adult↗
PubMed1975

Hypovolaemia and phaeochromocytoma.

The state of shock which frequently follows removal of a phaeochromocytoma is due to the hypovolaemia resulting from prolonged excessive secretion of vasoconstrictor substances and should be treated with intravenous fluids. The gradient between central and peripheral temperatures provides a reliable guide to the hypovolaemic state. Two illustrative cases are described.

Humans↗