Ergonomic problems with the Hawksley Random Zero Sphygmomanometer and their effect on recorded blood pressure levels.
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Biomedical subjects
Publications and source records attributed to R M Conroy.
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Stool samples were collected during August 1994 from seventy rural Maasai children under the age of five years who were living in the Maasailand region of the Kenyan Rift Valley. Microbiological analysis was carried out on these samples to identify which intestinal pathogens were present among the infant population of the Maasai. Of the samples studied 54% were pathogen positive. The most common pathogen isolated was Giardia lamblia which was detected in 31% of the samples. Other pathogens that were detected include: Entamoeba histolytica (23%), Enteropathogenic Escherichia coli (13%), Strongyloides stercoralis (4%), Blastocystis hominis (3%) and Cryptosporidium sp (3%). Although all samples were screened for Campylobacter and rotavirus, neither pathogen was detected. Water samples were taken from all the water sources in the study area and analysed microbiologically. Results showed that all the sources were contaminated with the faecal E. coli whose populations ranged from 14 CFU/100 ml to greater than 1800 CFU/100ml.
OBJECTIVES: The purpose of this study was to test the hypothesis that in occlusions of the superficial femoral artery, removal of atherosclerotic plaque would result in a higher long-term patency rate compared to balloon dilatation alone. A secondary hypothesis was that long term patency would be proportional to the amount of plaque removed. METHODS: A randomized controlled study of patients with occluded superficial femoral arteries was performed comparing balloon dilatation alone versus a 2.7 mm or a larger (4.0 mm or 4.7 mm) transcutaneous extraction catheter (TEC) atherectomy device followed by balloon dilatation. The effect of these devices on plaque area was assessed directly by intravascular ultrasound imaging. RESULTS: The mean occlusion length was 19.4 cm +/- 11.7 cm. The mean lumen area increased from 4.7 mm2 to 15.1 mm2, primarily due to balloon dilatation, but the mean atheroma area of 19.8 mm2 did not change with either size of TEC device. Although the initial procedure success rate was high (79%), the 6 month patency was only 45%. There was no difference in 6 month patency between the 3 groups. CONCLUSIONS: The data indicate that the TEC atherectomy devices do not remove a significant amount of atherosclerotic plaque in occluded superficial femoral arteries. The 6 month patency is no different with these atherectomy devices than with balloon dilatation alone. The larger (4.0 mm or 4.7 mm) TEC device does not remove any more tissue than the smaller (2.7 mm) device. The use of intravascular ultrasound to quantitate the effects of this atherectomy device provides important insights into the mechanism of action and lack of efficacy of the TEC atherectomy catheter.
Small-diameter portacaval H-grafts (partial shunts) effectively abolish bleeding from esophageal varices. Goals are 1) to prevent variceal hemorrhage by subtotal portal decompression, and 2) to minimize postshunt encephalopathy by maintaining substantial residual pressure and prograde flow in the portal vein. To reduce spontaneous shunting of portal blood away from the liver, we advocate ablation of collateral vessels after partial shunts. Others have performed partial shunts without collateral ablation. We postulated that ablation of collateral vessels would augment portal perfusion pressure and preserve prograde portal flow after partial shunts. In 15 patients undergoing 8 or 10 mm portacaval H-grafts, portal pressure was measured intraoperatively before and after ligation of principal venous collaterals. In another 13 patients, collateral embolization was performed during postoperative portography. The degree of portal perfusion was scored. Pressure measurements demonstrated a mean rise in portal pressure of 2.8 cm saline after ligation (P = 0.025). Angiographic perfusion scores after embolization improved by a mean of 0.57 points on a 4 point scale (P = 0.032). We conclude that intraoperative collateral ligation augments residual portal pressures and that postoperative collateral embolization improves portal flow patterns. Since both observed effects have been associated with decreased postshunt encephalopathy rates, ablation of collateral vessels must be an integral component of the partial portacaval shunt.
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BACKGROUND: Patients undergoing percutaneous recanalization of chronically occluded superficial femoral arteries were studied to determine which factors correlated with 1-year patency. Immediate change in ankle:brachial index (ABI), length of occlusion, tibial run-off, and the performance of supplemental catheter atherectomy were evaluated. METHODS: Eligible patients had at least one patient tibial run-off vessel and the absence of limb-threatening ischemia. Recanalization was performed via passage of a guidewire followed by balloon angioplasty. Tibial run-off was scored based on a modification of the angiogram scoring system of the Society for Vascular Surgery and the International Society for Cardiovascular Surgery. Supplemental transcutaneous extraction catheter atherectomy was randomly assigned to a sub-group of patients after initial experience with the recanalization technique. Clinical follow-up was employed to determine patency. RESULTS: Forty-two of 57 attempts (74%) at recanalization were immediately successful. Overall 1-year patency was 40% in 40 limbs that could be followed. In limbs with balloon angioplasty alone (n = 23), patency was 43% compared with 35% in those having supplemental atherectomy. Tibial run-off did not vary significantly between patent and occluded groups. When ABI increased by 0.3 or more, patency was 56% compared with 26% when the ABI increase was less than or equal to 0.1 (P = 0.13). Occlusion length averaged 18.1 +/- 10.6 cm for all limbs and did not vary significantly between early successes and failures. Limbs with short occlusions (less than or equal to 5 cm, n = 8) had 63% patency compared with 38% patency for limbs with long occlusions (greater than 25 cm, n = 16), but the difference was not significant by analysis of variance. CONCLUSIONS: An initial change in ABI was most predictive for patency, whereas no correlation with tibial run-off was demonstrated. Atherectomy did not increase patency. Short occlusions were more likely to remain patent than long ones, but overall patency was lower than described in other series.
The first European trial of iodixanol (Nycomed Imaging AS) in adult intravenous urography is reported. Iodixanol is a new non-ionic, dimeric contrast medium of low osmolality. A double-blind, randomized, three group parallel study comparing iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (Niopam) was undertaken. A total of 173 of 180 patients entered completed the trial. Efficacy was evaluated with regard to overall diagnostic information and pyelographic density 5 min after contrast medium administration. Efficacy was found to increase with increasing iodine concentration, with no significant difference between the three contrast media. The incidence of adverse events was low, with no significant difference between the groups. Discomfort occurred less frequently with iodixanol than with iopamidol. We conclude that iodixanol is a safe and efficacious contrast medium for use in intravenous urography.
We combined a database of paired blood pressure measurements taken using the Hawksley random-zero sphygmonanometer and a standard mercury sphygmomanometer and a database of paired measurements made on a SpaceLabs 90202 ambulatory blood pressure recorder and standard sphygmomanometer to determine how the SpaceLabs 90202 would have fared if it had been assessed against the Hawksley random-zero sphygmomanometer instead of a standard sphygmomanometer. The pooled database contained 255 triplicate readings. Using the standard sphygmomanometer as gold standard, the Spacelabs had a median error of 2 mm/Hg for both systolic and diastolic. Against the Hawksley random-zero sphygmomanometer, median error was -3 mm systolic and -6 mm diastolic. The proportion of errors > 10 mm rose from 11% (systolic) and 9% (diastolic) with the standard sphygmomanometer to 16% and 29% with the Hawksley random-zero sphygmomanometer. Because it underestimates systolic and diastolic pressures, the use of the Hawksley random-zero sphygmomanometer as a gold standard may have resulted in misleading conclusions about performance of some automated BP recorders.
The Hawksley random zero sphygmomanometer is used in all aspects of blood pressure research, from clinical trials to evaluation of new blood pressure recorders. It is designed to reduce observer bias in blood pressure measurement. The problem is that it also underestimates blood pressure. Furthermore, this was first reported more than two decades ago. In this paper Rónán Conroy and colleagues explore the consequences of using an inaccurate instrument for important research and why prestigious organisations like the World Health Organisation continue to use it.
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OBJECTIVE: To assess parent-child agreement of child disability and pain. METHODS: Twenty children with juvenile chronic arthritis aged between 8 and 16 years and their mothers were assessed using a recently developed measure of child disability and pain. RESULTS: Results demonstrated a high level of agreement between children and their mothers with respect to disability. However, there was no correlation between the children's and their mothers' assessment of pain. CONCLUSION: This suggests that parents of children with chronic arthritis give accurate information regarding disability, but not regarding pain.
We report on the 15-year prognosis of 720 male and 246 female 28-day survivors of a first myocardial infarction or episode of unstable angina who were aged under 60 years at the time of admission to the study. Women were on average 1.9 years older than men, had higher cholesterol levels, a higher prevalence of hypertension and angina prior to admission and a higher proportion were lifetime non-smokers. Women were more likely to be admitted with unstable angina rather than infarction. When adjusted for age, smoking status, angina, hypertension and the difference in prevalence of infarction, women had a relative risk of death of 1.054 in a 15-year life table mortality analysis. Prognostic differences between the sexes reported may be the result of failure to allow for differences in other prognostic factors.
AIDS in the Republic of Ireland has so far mainly been associated with intravenous drug use. However, because of growing public pressure to mount an AIDS campaign aimed at potentially vulnerable sub-groups, we conducted a survey of knowledge and attitudes related to AIDS among 891 Irish schoolchildren in the senior years of secondary school. Although virtually none of the children had received any classroom education on AIDS and no national education programme had been undertaken at the time of the survey, levels of knowledge were high among the pupils studied, and compared favourably with levels found using the same questionnaire among San Franciscan pupils. Higher levels of knowledge were found among urban pupils and, although some sex differences in knowledge emerged, there was no consistent pattern in these. No school surveyed showed sufficient misinformation to warrant a systematic education programme.
Autonomic neuropathy is associated with an increased incidence of silent myocardial infarction and sudden death. The purpose of this study was to investigate the prevalence of silent myocardial ischaemia in diabetic patients with autonomic neuropathy and without. Five standard autonomic function tests were performed on 41 men with diabetes: postural change in blood pressure, postural change in heart rate, heart rate response to deep breathing, heart rate response to Valsalva's manoeuvre, and blood pressure response to sustained handgrip. There were 17 patients with autonomic neuropathy (group A) and 24 with normal autonomic function (group B). All patients underwent 24 hour ambulatory electrocardiographic monitoring to detect silent ischaemia. There was no significant difference in risk factors for coronary artery disease or history of angina pectoris between these groups. The prevalence of silent ischaemia was 64.7% in group A (95% confidence interval (95% CI) 38.33 to 85.79%) and 4.1% in group B (95% CI 0.11 to 21.12%). This represents a relative risk of 42.2 (95% CI 4.5 to 39.4, p less than 0.001). These results are consistent with the concept that autonomic neuropathy may prevent the development of anginal pain and thus obscure the presence of ischaemic heart disease. Twenty four hour ambulatory electrocardiographic monitoring may identify a subgroup of diabetic patients with autonomic neuropathy who have myocardial ischaemia and to whom treatment may be offered.
OBJECTIVE: To investigate the incidence and prognostic significance of fasting hyperglycemia in a large group of patients with a first myocardial infarction. RESEARCH DESIGN AND METHODS: Blood glucose was measured after an 8-h overnight fast in 752 patients with a first myocardial infarction. Three groups of patients were identified: patients with normal fasting blood glucose (92.5%), patients with fasting hyperglycemia but no prior history of glucose intolerance (3%), and patients previously known to have diabetes mellitus (4.5%). RESULTS: The fasting hyperglycemic patients were significantly older and had significantly more in-hospital complications than the normal blood glucose group. Previously known diabetic subjects tended to be older and had more mechanical complications postinfarction than the group with normal blood glucose but the difference did not reach statistical significance. There was no significant difference between the diabetic subjects and patients with fasting hyperglycemia in mean age and in-hospital prognosis. CONCLUSIONS: Fasting hyperglycemia detected after a first myocardial infarction is associated with a poor in-hospital prognosis that was not due to larger infarct size, as reflected in peak levels of cardiac enzymes. The measurement of a fasting blood glucose level provides additional information in identifying high-risk groups of patients postinfarction.
The relationship of coronary artery disease to plasma lipoproteins was examined in 43 men admitted to our unit with suspected ischemic heart disease. Coronary arteriography was performed, and a score reflecting the severity of disease was assigned to the angiogram. Plasma, obtained after a 12-h overnight fast, was assayed for triglycerides, total cholesterol, high-density lipoprotein (HDL) cholesterol, and HDL-3 cholesterol. HDL-2 cholesterol was found by subtraction. The cholesterol contents of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) were quantitated by the Freidwald equation. Men with high coronary scores tended to be older, and subjects with moderate coronary disease had significantly higher total and LDL cholesterol values than those with minimal disease. Age was the only factor to be significantly associated with coronary score and there was no significant association between coronary score and total LDL and HDL cholesterol or its subfractions when the age factor was taken into account.
We investigated the relationship between atrioventricular block and in-hospital mortality in 705 successive patients admitted with a first Q-wave myocardial infarction of the anterior or inferior wall. Second- or third-degree atrioventricular block developed in 61 (8.6 per cent) patients and was more frequent in inferior (12.4 per cent) than anterior infarctions (4.9 per cent). A multiple logistic regression identified three factors which were independently correlated with block: inferior infarction, older age and larger infarct size as determined by cardiac enzymes. Mortality was 27.9 per cent in patients with block and 9.3 per cent in those without; it was significantly higher in both anterior (47.0 per cent vs 11.8 per cent) and inferior (20.4 per cent vs 6.7 per cent) infarction groups. When age, infarct size, infarct site and block were analysed simultaneously as predictors of death, block was a significant independent prognostic factor. The relative risk of death, corrected for age and infarct size, in patients showing block was similar for anterior and inferior infarction. Analysis of deaths revealed a higher incidence of unheralded death in inferior infarcts associated with high-degree block.