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PubMedDate not supplied

Blood lead level and blood pressure during pregnancy in South Central Los Angeles.

In many studies in which the relationship between blood pressure and blood lead level has been examined, investigators have found significant--but small--associations. There was only one previous report of a significant association of blood lead with blood pressure in pregnant women. We measured blood lead level and sitting blood pressure of 1,627 women in their third trimester of pregnancy. We eliminated subjects with known causes of hypertension. Most women (98.4%) were normotensive. We controlled for body mass index, age, and stress--among other factors--and constructed multiple-regression models of lead association with diastolic and systolic blood pressures. Immigrants (73% of total) had significantly higher blood lead levels and different blood pressures than nonimmigrants, suggesting that analysis be stratified by "immigrant, nonimmigrant" status. Positive relationships between blood lead level and blood pressure were found only for immigrants (p < or = .001). From the 5th to 95th blood-lead percentiles (0.9-6.2 microg/dl) in immigrants, systolic blood pressure increased 2.8 mm Hg, and diastolic blood pressure increased 2.4 mm Hg. Higher prior lead exposure of immigrants (97.7% from Latin countries) than nonimmigrants might explain the differential effect of these low levels of blood lead on blood pressure in nonimmigrants. Perhaps some immigrants are at higher risk than nonimmigrants for lead-associated elevated blood pressure during pregnancy, despite blood lead levels within the currently considered acceptable range.

Adult↗
PubMed1996

Conventional and ambulatory blood pressure measurement in older patients with isolated systolic hypertension:second progress report on the ambulatory blood pressure monitoring project in the Syst-Eur trial.

OBJECTIVES: To compare clinic and ambulatory blood pressure measurement and the reproducibility of these measurements in older patients with isolated systolic hypertension.PATIENTS: A total of 477 patients aged >/= 60 years with isolated systolic hypertension on clinic measurement were monitored during the placebo run-in phase of the Syst-Eur trial. METHODS: The time-weighted 24 h blood pressure, clock time day and night blood pressure, the cumulative sum-derived crest and trough blood pressure and the high and low blood pressure levels of the square-wave model were computed. The daily alteration between the high and low blood pressure spans was quantified using the clock time day-night difference, the cumulative sum-derived circadian alteration magnitude, the Fourier amplitude and the difference between the high and low blood pressure levels of the square-wave model. RESULTS: The daytime ambulatory systolic blood pressure was, on average, 21 mmHg lower than the clinic blood pressure, whereasthe diastolic blood pressure was, on average, similar with both techniques of measurement. In the 132 patients who underwent repeat measurements, clinic blood pressure levels and the parameters describing the difference betgween the daily high and low blood pressure spans were equally reproducible. However, both were less reproducible than the ambulatory blood pressure levels. The repeatability coefficients, expressed as percentages of near maximum variation, were 50 and 51% for the clinic systolic and diastolic blood pressures, 30 and 33% for the mean 24 h systolic and diastolic blood pressures and between 44 and 54% for the parameters describing the daily alteration between the high and low blood pressure spans. CONCLUSION: In older patients with isolated systolic hypertension, clinic and ambulatory systolic blood pressure may differ greatly; the prognostic significance of this difference remains to be elucidated. Furthermore, the level of blood pressure in these patients is more reproducible by ambulatory measurement than it is by clinic measurement.

Journal Article↗
PubMed2004

Blood and bioidentity: ideas about self, boundaries and risk among blood donors and people living with hepatitis C.

Clinical medicine and biotechnology increasingly utilise and transform human bodily tissues in novel ways. Today more and more tissues--blood, whole organs, ova, embryos, sperm, skin, bone, heart valves, cellular material, bone marrow and corneas--can be transferred between donors and recipients. Hence more and more people in developed nations have the experience of giving a fragment of their body to another, or receiving such a fragment as part of some kind of therapy. These systems for the circulation of tissues raise the question of what we have termed 'bioidentity'. Bioidentity describes our common-sense understanding of our bodies as 'ours', as both supporting and being included in our social and subjective identities. Within this framework, how are we to understand the status of detachable bodily fragments like blood, ova or organs? As parts of our bodies do they retain a trace of our identity after donation, or are they detachable things? What is our relationship, if any, to the patient who receives our tissues as part of their treatment? This paper investigates the specific case of blood transfusion and donation. It draws upon in depth interviews with 55 people who have specific experience with blood. They either have hepatitis C (are HCV+) acquired by transfusion or intravenous drug use, or have donated blood or received a blood transfusion but are free of hepatitis C (are HCV-). We analyse this material according to the themes--Donated Blood as 'Self', Blood as Alienable, Blood as Communal Substance, and Contaminated Gifts and the Blood of Strangers. We find that, generally speaking the HCV+ and HCV- groups share very similar ideas about blood donation and transfusion. For a minority of both groups, blood was understood as a decisive site of self irrespective of location, but for the remainder donated blood was either ambiguous with regard to identity, a shared substance, or not considered to have any lingering relationship to the self once given. However both groups regarded blood as strongly imbued with 'risk identity'. In particular the HCV+ interviewees regarded their blood as a dangerous personal attribute, one that they must be careful to withhold from circulation, whereas the blood donors felt obliged to donate their blood precisely because they considered it clean and risk free.

Adult↗
PubMed2001

Comparison of blood counts in venous, fingertip and arterial blood and their measurement variation.

We compared routine blood pictures in venous, fingertip and arterial blood and their measurement variation. A pair of venous and fingertip blood samples were simultaneously collected from 24 volunteers, and another pair of venous and arterial samples from another 12 volunteers. The volunteers were healthy adults, aged 20-22 years, with males and females in equal numbers. Three aliquots of blood were taken from each person for three measurements of blood counts, including haemoglobin concentration and haematocrit, using an automatic haematology analyser. Compared to arterial blood, there was a significant increase of erythrocyte count (2.7%) and haematocrit (3.1%) in the venous blood. The total and large leucocyte counts were significantly higher (9.2% and 12.6%, respectively) in the fingertip blood than in the venous blood. There were a decreasing number of leucocytes in the fingertip blood with repeated sampling. The intermeasurement variation for total leucocyte or haemoglobin measurement was significantly larger as measured with the fingertip blood or arterial blood than with the venous blood. The intermeasurement coefficients of variation of haemoglobin (1.3%) and small leucocyte ratio or platelet (approximately 4.0%) measurements with venous and arterial blood were the smallest and largest, respectively. Volume of arterial plasma was diminished by 2-3% after microcirculation. Elevation of total leucocyte count in the fingertip blood was mainly due to the increase of granulocytes. Measurement with venous blood was of better precision than with fingertip or arterial blood.

Adult↗
PubMed2001

Recent advances in blood pressure measurement technology: normalized blood pressure measurement with a double-cuff sphygmotonometer.

BACKGROUND: In our previous studies of 24-h blood pressure measurement, basal blood pressure (minimum sleep-time blood pressure) showed the strongest correlation with hypertensive target-organ damage. We have currently devised a new accurate method of blood pressure measurement that entails recording casual blood pressure waves by means of a double-cuff sphygmotonometer, and attempted to normalize casual blood pressure to basal blood pressure. METHODS: The double-cuff sphygmotonometer records the arterial pressure wave, from which, using the formula (P0 = phi(-1)(i) x Pi), we attempted a normalization of casual blood pressure (Pi) to values close to those of the basal blood pressure (P0). True basal blood pressure was measured by an indirect ambulatory blood pressure monitoring device (TM2425, A&D Co. Ltd., Tokyo, Japan). The subjects were 54 normotensive volunteers and 156 out-patients with essential hypertension [63 with World Health Organization (WHO)-II stage and 93 with WHO-I stage, including 47 subjects with white-coat hypertension] not receiving medication. RESULTS: The coefficient of correlation (r) between normalized diastolic blood pressure (Pd0') and true diastolic basal blood pressure (Pd0) was 0.82 (mean difference = 1 +/- 9.8 mmHg), that between normalized systolic blood pressure (Ps0') and true systolic basal blood pressure (Ps0) being 0.78 (1 +/- 13 mmHg) in 210 subjects. When an office mean blood pressure (MBP) of 116 mmHg was taken as the standard for identifying the WHO-I group, the sensitivity was 70% (65/93) and the specificity 67% (42/63), but when an MBP0 [MBP0' = (Ps0'-Pd0')/3 + Pd0'] of 89 mmHg was the standard, the sensitivity was 82% (76/93) and the specificity 90% (57/63), both significantly higher than the corresponding values for office MBP (P < 0.05). CONCLUSION: We devised a new double-cuff sphygmotonometer and normalizing function (phi(-1)) and, using these methods, calculated the normalized blood pressure in hypertensive out-patients, which may make it possible to identify degrees of severity of hypertension in terms of WHO stages.

Algorithms↗
PubMed1999

The use of fibrin tissue adhesive to reduce blood loss and the need for blood transfusion after total knee arthroplasty. A prospective, randomized, multicenter study.

BACKGROUND: Total knee arthroplasty is associated with major postoperative blood loss of approximately 800 to 1200 milliliters, and blood transfusion is frequently required. With the increased concern about the risks of blood transfusion, various methods of blood conservation in orthopaedic surgery have been studied. The most appropriate solution, however, is to reduce the loss of blood during and after an operation. The present prospective, controlled, randomized study was designed to evaluate the hemostatic efficacy of the use of fibrin tissue adhesive in patients managed with total knee arthroplasty. METHODS: Fifty-eight patients who were scheduled to have a total knee arthroplasty were randomly divided into two groups: a control group, in which the standard means of hemostasis were applied, and a treatment group, in which the standard means to control local bleeding were applied and a fibrin tissue adhesive was sprayed on the internal aspects of the operative field before skin closure. All operations were performed in a bloodless field with use of a pneumatic tourniquet. All patients received low-molecular-weight heparin as thromboprophylaxis twelve hours before the operation and every twelve hours postoperatively. Blood loss during the operation was evaluated by measuring the volume in the suction apparatus and by estimating the amount of lost blood in the swabs at the end of the operation. The apparent postoperative lost blood was determined by measuring the volume in the suction-drain bottles. All blood transfusions were recorded. RESULTS: The mean apparent postoperative blood loss (and standard deviation) in the fibrin-tissue-adhesive group was 360+/-287.7 milliliters compared with 878+/-403.0 milliliters in the control group, with a mean difference of 518 milliliters (p<0.001). The decrease in the level of hemoglobin was 25+/-10 grams per liter in the treatment group compared with 37+/-12 grams per liter in the control group (p<0.001). Sixteen patients (55 percent) in the control group required a blood transfusion and eight (28 percent) required two units of blood, whereas only five (17 percent) of the patients in the fibrin-tissue-adhesive group required a blood transfusion and only one (3 percent) required two units (p = 0.004). The number of adverse events was comparable between the two groups. None of the adverse events were considered to be related to the use of fibrin tissue adhesive. One death, which was due to massive pulmonary embolism, was reported in the control group. No seroconversion was reported at three and six months after the operation. CONCLUSION: The use of fibrin tissue adhesive in total knee arthroplasty seems to be an effective and safe means with which to reduce blood loss and blood-transfusion requirements. Furthermore, the importance of these findings was enhanced by a significant reduction in blood loss, in the postoperative decrease in the level of hemoglobin, and in blood-transfusion requirements despite preoperative thromboprophylaxis with low-molecular-weight heparin.

Aged↗
PubMed2005

[Change of free hemoglobin content after mixing type B whole blood with different amounts of type O whole blood].

To investigate the changes of free hemoglobin (FHb) content after mixing type B whole blood with different amounts of type O whole blood at room temperature and at 37 degrees C, two lots of type B whole blood stored at 4 degrees C for 24 hours were randomly taken as recipient blood, and were packed as 60 ml respectively. Type O blood was taken as donor blood. 60 ml type B whole bloods were mixed with different amounts of type O whole blood, i.e. with 9, 12, 15 and 18 ml. The mixed blood was packed into 100 ml plastic blood bags and stored at 37 degrees C or room temperature, shaken once every 15 minutes. Free hemoglobin content was determined for the harvested samples at 1, 2, 4, 8 and 12 hours after store. The results showed that there was no significant elevation of FHb within 12 hours after mixing B whole blood with different amounts of type O whole blood. In another lot, there was obvious difference in FHb after 1 hour store along with the prolongation of store at either room temperature or 37 degrees C. In one lot, there was no difference of FHb (P > 0.05) during 1 - 8 hours of store at room temperature or 37 degrees C, but significant difference at 12 hours of store (P < 0.001). In another lot, there was no difference of FHb (P > 0.05) within 1 hour of store at room temperature and at 37 degrees C, but significant difference during 2 approximately 8 hours of store (P < 0.001). It is concluded that the FHb would not change significantly within 12 hours after type B blood was mixed with 1 200 ml of type O whole blood, but when the mixed blood was placed at room temperature or at 37 degrees C for 8 hours, the FHb content approaches, even exceeds 170.4 mg/L which was observed in the blood stored for 2 days. It suggests that freshly collected blood must be put into refrigerator of 2 approximately 4 degrees C for storing as soon as possible, so as to decrease the catabolism of erythrocyte and the releasing of FHb and other metabolites which are deleterious to the recipients.

ABO Blood-Group System↗
PubMed1989

Cardiovascular responses in the laboratory and in the natural environment: is blood pressure reactivity to laboratory-induced mental stress related to ambulatory blood pressure during everyday life?

Cardiovascular activity recorded at rest and during mental stress in the laboratory was studied in relation to ambulatory recorded cardiovascular activity at work and at home. Fifty-five Type A men (M = 42.4 years) underwent a standardized laboratory mental stress protocol in which systolic blood pressure, diastolic blood pressure, and heart rate were recorded at baseline and during a 15 min mental arithmetic task (MAT). On a subsequent day, ambulatory blood pressure and heart rate were recorded at 20 minute intervals for 12-14 hr during normal activities at home and at work. Subjects completed a behavioral diary concurrently with each cuff inflation. High and Low groups were identified based upon a median split of their cardiovascular response levels at baseline and during the MAT. Subjects with high systolic blood pressure levels during the MAT had high systolic blood pressure at home, at work, during physical activity, and when they reported being 'stressed'. Baseline systolic blood pressure in the laboratory was less consistently related to ambulatory systolic pressure across ambulatory conditions. Diastolic blood pressure at baseline was related to ambulatory diastolic blood pressure at work, at home, and when resting. Diastolic blood pressure during the MAT was associated with higher diastolic pressure at work and at home. Heart rate at baseline and during the MAT was related to heart rate at work and during physical activity. Change scores derived by subtracting mean values during the MAT from baseline resting levels were not associated with ambulatory blood pressures or heart rates under any daily conditions. In the best case, systolic blood pressure measured during the MAT was related to systolic blood pressure during physical activity, to systolic blood pressure and heart rate during mental stress, to systolic and diastolic blood pressure at rest, and to systolic blood pressure and heart rate at work but not at home. We conclude that levels of blood pressure and heart rate measured in the laboratory, but not reactivity (i.e, change scores) during the MAT, are related to blood pressure and heart rate levels recorded in the natural environment, especially in the work setting.

Activities of Daily Living↗
PubMed1999

Diagnosis of catheter-related bacteraemia: a prospective comparison of the time to positivity of hub-blood versus peripheral-blood cultures.

BACKGROUND: A method of diagnosing catheter-related infection (CRI) without removing the catheter would be useful. An earlier positivity of central compared with peripheral venous-blood cultures may be associated with catheter-related bacteraemia. We evaluated prospectively the differential time to positivity (DTP) of paired blood cultures drawn simultaneously via the catheter hub and from a peripheral venous site. METHODS: Over a 14-month period in an intensive-care unit of a cancer referral centre, simultaneous hub-blood and peripheral-blood cultures (a mean of two per patient) were obtained from patients with a suspected CRI. According to clinical criteria and quantitative culture of the catheter tip, cases were classified as CRI or sepsis of other origin. At least one pair of hub-blood and peripheral-blood cultures was obtained within 48 h before catheter removal, and we recorded the DTP between hub-blood and peripheral-blood cultures with an automatic device for detection of blood culture positivity. FINDINGS: We analysed 93 catheters removed because of suspicion of CRI. In 28 episodes, the same micro-organisms were found in both hub-blood and peripheral-blood cultures. A diagnosis of definite bacteraemic CRI was made in 16 of the 17 patients in whom a positive hub-blood culture was detected at least 2 hours earlier than peripheral-blood culture. About half (9/17) of these episodes occurred in long-term (>30 days) devices. CRI was excluded in ten of the 11 patients with a DTP lower than 2 h. The DTP of paired blood cultures was significantly greater in patients with CRI than in others (p<10(-4)). A cut-off DTP value of 120 min had 91% specificity and 94% sensitivity for the diagnosis of CRI. Three of 17 episodes with only hub-blood culture positive were associated with CRI. INTERPRETATION: This prospective study suggests that measurement of the differential time to positivity between hub-blood and peripheral-blood cultures is a simple and reliable tool for in-situ diagnosis of catheter-related sepsis in cancer patients. Further studies are needed to confirm these data for short-term catheters.

Bacteremia↗
PubMedDate not supplied

Relationship of blood lead levels to blood pressure in battery workers.

The effect of lead exposure on blood pressure in the modern industrial setting is controversial. In this study, we followed 67 workers in a lead-battery plant for 6-10 y, and blood pressure and blood lead levels were measured every 6 mo. Weight, height, alcohol intake, cigarette smoking, and age were recorded. Partial correlation coefficients showed that initial systolic blood pressure, age, and body mass index (i.e., weight/height squared) accounted for 25%, 30.9%, and 20.2%, respectively, of the variance in systolic blood pressure (p < .001 in all cases). Conversely, average blood lead levels (13 +/- 3 tests/worker) accounted for only 0.4% of the variance (not significant). Repeated-measures analysis of variance showed a small--but significant--association between blood lead levels and systolic blood pressure. There was a negative correlation between blood lead levels and diastolic blood pressure. There were 18 men with average blood lead levels that were less than 30 micrograms/dl (average = 25 +/- 3 micrograms/dl), and 32 men had levels of 40 micrograms/dl or more (average = 47 +/- 6 micrograms/dl). The mean final systolic blood pressure, adjusted for age, and initial systolic blood pressure were 117 +/- 13 mm Hg and 114 +/- 11 mm Hg, respectively. We concluded that blood lead levels had no clinically significant effect on blood pressure in lead-battery workers. The main predictors of the follow-up systolic blood pressure were age, body mass index, and initial systolic blood-pressure measurements.

Adult↗
PubMed1993

The association of blood lead and blood pressure in population surveys.

Several reports from large population surveys have indicated that blood lead is positively related to blood pressure. We assessed this relation in 1,703 men (median blood lead = 83 micrograms per liter) and 1,661 women (median blood lead = 60 micrograms per liter), age 28 to 67 years, who participated in the first follow-up examination of the MONICA Augsburg cohort study in 1987-1988. Crude analyses confirmed a strong, positive association of blood lead concentrations with systolic and diastolic blood pressure. We identified age, body mass index, hematocrit, and alcohol consumption as the quantitatively most important confounders of this association. Adjustment for these variables, in particular for hematocrit and alcohol consumption, considerably reduced the magnitude of the blood lead effect on blood pressure. There were no indications for marked nonlinearity or threshold effects. After control of confounders, a difference of 100 micrograms per liter in blood lead levels, corresponding to rather extreme positions in the lower and upper end of the population blood lead distribution, related to estimated blood pressure increases of less than 3 mmHg. The appropriateness of treating hematocrit and alcohol consumption as confounders of the blood lead-blood pressure relation is discussed on the basis of current pathophysiologic concepts. We conclude that hematocrit should always be taken into account as a relevant confounder. On the other hand, the interrelation of alcohol consumption, blood lead, and blood pressure is presently not clearly understood; that is, its appropriate analytic handling cannot be determined. The consequences of these considerations on estimates of the blood lead effect on blood pressure may be both over- and underestimations.

Adult↗
PubMed1999

Effects of benidipine hydrochloride on 24-hour blood pressure and blood pressure response to mental stress in elderly patients with essential hypertension.

OBJECTIVE: The effects of a new dihydropyridine calcium antagonist, benidipine hydrochloride, on 24-hour blood pressure and blood pressure response to mental arithmetic test were investigated. SUBJECTS: Ten elderly patients with essential hypertension (mean age: 65+/-4 years; 7 male and 3 female). METHOD: After a control period of 4 weeks, 4 mg benidipine was administered once daily in the morning for 12 weeks. Ambulatory blood pressure was monitored using a non-invasive automatic portable device with the cuff-oscillometric method at the end of both the control and treatment periods. RESULTS: Benidipine administration significantly decreased 24-hour blood pressure, while little change was noted in heart rate. Daytime blood pressure decreased significantly, from 148.2+/-11.5/90.8+/-8.8 to 133.8+/-9.2/82.5+/-10.8 mmHg. However, no significant decrease in nighttime diastolic blood pressure was noted, and the decrease in nighttime systolic blood pressure was small (from 129.8+/-9.9/77.1+/-7.6 to 121.8+/-10.1/74.7+/-9.1 mmHg). No significant changes were observed in diurnal variability of blood pressure and heart rate. The decrease in systolic blood pressure by benidipine administration showed a significant positive correlation with systolic blood pressure before treatment in the 24-hour and daytime periods. Single cosinor analysis showed that benidipine administration significantly decreased MESOR of both systolic and diastolic blood pressure, without an increase in amplitude. Both systolic and diastolic blood pressure during mental arithmetic test were significantly decreased after treatment with benidipine, and the increase in systolic blood pressure induced by mental arithmetic test was also significantly attenuated. CONCLUSIONS: These findings indicate that administration of benidipine once daily in the morning effectively decreases blood pressure and attenuates blood pressure response to mental stress. Neither reflex tachycardia, deterioration of diurnal blood pressure change, nor excessive lowering of nighttime blood pressure was observed after benidipine administration. It is suggested that benidipine is a potent and long-lasting calcium antagonist which may be useful for the treatment of elderly hypertensive patients with cardiovascular disease.

Administration, Oral↗
PubMed2002

Preoperative blood volume deficit influences blood transfusion requirements in females and males undergoing coronary bypass graft surgery.

STUDY OBJECTIVE: To evaluate whether preoperative blood volume and postoperative blood loss influence blood transfusion in females and males undergoing coronary artery bypass graft (CABG) surgery. DESIGN: Prospective study. SETTING: Anesthesiology department of a teaching hospital. PATIENTS: 57 CABG patients (21 females and 36 males). MEASUREMENTS: Blood volume was determined using the radioactivity dilution method. Preoperatively, each patient received intravenous (IV) injection of 1 mL Albumin I(131) tracer having 25 microcuries of radioactivity. Five-milliliter blood samples were collected at different intervals. From these samples, hematocrit (Hct) value, preoperative total blood volume, red blood cell (RBC) volume, and plasma volume were determined. Postoperatively, some consenting patients received another 1 mL dose of the tracer, and the postoperative blood volumes were determined. If a patient received a blood transfusion, the units of packed red blood cells (PRBCs), platelets, or fresh frozen plasma (FFP) transfused were recorded. For each patient we recorded the gender, age, weight, height, body surface area (BSA), preoperative Hct, duration of surgery, and discharge Hct. RESULTS: Preoperatively, the mean total blood volume, RBC volume, and plasma volume, respectively, were 2095 mL/m(2), 631 mL/m(2), and 1,465 mL/m(2) in females; and 2,580 mL/m(2), 878 mL/m(2), and 1,702 mL/m(2) in males. The preoperative blood volumes were significantly lower (p < 0.01) in females than in males. There was no significant difference between males and females in the extent of blood loss during CABG. Intraoperatively, females received PRBC transfusion of 1.38 units, significantly more (p < 0.01) than the 0.39 units received by males. During the entire hospital stay, females received 4.33 units of PRBC, significantly more than (p < 0.02) the 1.33 units received by males. Significantly more (p < 0.01) females (12 of 21) received intraoperative PRBC transfusion than did males (6 of 36). Multiple logistic regression analysis of the data showed that PRBC transfusion was significantly correlated with the preoperative total blood volume and RBC volume. CONCLUSION: The greater need for blood transfusion in females than in males during CABG is primarily attributable to significantly lower preoperative total blood volume and RBC volume in females.

Aged↗
PubMed1997

Prediction of mortality by ambulatory blood pressure monitoring versus screening blood pressure measurements: a pilot study in Ohasama.

OBJECTIVE: To compare the prediction of mortality by ambulatory blood pressure monitoring and screening blood pressure measurements in a general population. DESIGN: A prospective cohort study. PATIENTS AND METHODS: We obtained blood pressure data for 1542 subjects (565 men and 977 women) aged > or = 40 years who were followed up for up to 8.1 years (mean 5.1 years). Subjects were subdivided into five groups according to their ambulatory and screening blood pressure levels. The prognostic significance of blood pressure for mortality was examined by the Cox proportional hazards regression model. RESULTS: The association between blood pressure level and mortality was more distinctive for the ambulatory blood pressure than it was for the screening blood pressure. The risk of cardiovascular mortality increased significantly for the highest quintiles of 24 h ambulatory blood pressure, whereas there was no significant association between the screening blood pressure and the cardiovascular mortality. When both 24 h and screening blood pressure values were included in the Cox model, only the systolic ambulatory blood pressure was related significantly to the increased risk of cardiovascular mortality. CONCLUSIONS: The ambulatory blood pressure had a stronger predictive power for mortality than did the screening blood pressure. This appears to have been the first study of the prognostic significance of ambulatory blood pressure monitoring versus screening blood pressure measurements in a general population.

Adult↗
PubMed1999

Task force IV: Clinical use of ambulatory blood pressure monitoring. Participants of the 1999 Consensus Conference on Ambulatory Blood Pressure Monitoring.

OBJECTIVE: To reach a consensus on the clinical use of ambulatory blood pressure monitoring (ABPM). METHODS: A task force on the clinical use of ABPM wrote this overview in preparation for the Seventh International Consensus Conference (23-25 September 1999, Leuven, Belgium). This article was amended to account for opinions aired at the conference and to reflect the common ground reached in the discussions. POINTS OF CONSENSUS: The Riva Rocci/Korotkoff technique, although it is prone to error, is easy and cheap to perform and remains worldwide the standard procedure for measuring blood pressure. ABPM should be performed only with properly validated devices as an accessory to conventional measurement of blood pressure. Ambulatory recording of blood pressure requires considerable investment in equipment and training and its use for screening purposes cannot be recommended. ABPM is most useful for identifying patients with white-coat hypertension (WCH), also known as isolated clinic hypertension, which is arbitrarily defined as a clinic blood pressure of more than 140 mmHg systolic or 90 mmHg diastolic in a patient with daytime ambulatory blood pressure below 135 mmHg systolic and 85 mmHg diastolic. Some experts consider a daytime blood pressure below 130 mmHg systolic and 80 mmHg diastolic optimal. Whether WCH predisposes subjects to sustained hypertension remains debated. However, outcome is better correlated to the ambulatory blood pressure than it is to the conventional blood pressure. Antihypertensive drugs lower the clinic blood pressure in patients with WCH but not the ambulatory blood pressure, and also do not improve prognosis. Nevertheless, WCH should not be left unattended. If no previous cardiovascular complications are present, treatment could be limited to follow-up and hygienic measures, which should also account for risk factors other than hypertension. ABPM is superior to conventional measurement of blood pressure not only for selecting patients for antihypertensive drug treatment but also for assessing the effects both of non-pharmacological and of pharmacological therapy. The ambulatory blood pressure should be reduced by treatment to below the thresholds applied for diagnosing sustained hypertension. ABPM makes the diagnosis and treatment of nocturnal hypertension possible and is especially indicated for patients with borderline hypertension, the elderly, pregnant women, patients with treatment-resistant hypertension and patients with symptoms suggestive of hypotension. In centres with sufficient financial resources, ABPM could become part of the routine assessment of patients with clinic hypertension. For patients with WCH, it should be repeated at annual or 6-monthly intervals. Variation of blood pressure throughout the day can be monitored only by ABPM, but several advantages of the latter technique can also be obtained by self-measurement of blood pressure, a less expensive method that is probably better suited to primary practice and use in developing countries. CONCLUSIONS: ABPM or equivalent methods for tracing the white-coat effect should become part of the routine diagnostic and therapeutic procedures applied to treated and untreated patients with elevated clinic blood pressures. Results of long-term outcome trials should better establish the advantage of further integrating ABPM as an accessory to conventional sphygmomanometry into the routine care of hypertensive patients and should provide more definite information on the long-term cost-effectiveness. Because such trials are not likely to be funded by the pharmaceutical industry, governments and health insurance companies should take responsibility in this regard.

Antihypertensive Agents↗
PubMed1986

Haematological, immunological and endocrinological aspects of chronic high frequency blood sampling in rats with replacement by fresh or preserved donor blood.

Haematological, immunological and endocrinological aspects of blood transfusions with either freshly collected or preserved donor blood were investigated in chronically cannulated unrestrained rats. Three anticoagulant preservatives were tested: citrate, citrate-dextrose and citrate-phosphate-dextrose-adenine (CPDA-1). Prolactin was used as an indicator of stress in endocrine studies. The repeated collection of 4 ml blood at 2-week intervals did not affect normal blood composition. Whole blood of rats could be stored in citrate, citrate-dextrose or CPDA-1 for 8, 22 or 35 days, respectively. Blood transfusions with fresh or preserved donor blood of F1 (R X U) rats did not affect normal blood composition nor did it induce immunological responses in F1 rats. Frequent blood sampling for several hours at highest rates of 1 sample/min did not affect prolactin secretion when blood volume reduction was replaced by blood transfusions with fresh donor blood. However, compensation with preserved blood affected prolactin secretion significantly. Blood transfusions did not affect health, behaviour, cyclicity or pseudopregnancy. The application of blood transfusion in chronically cannulated rats appeared to be quite simple. Its advantages are the possibility of following individual secretion patterns of blood-bound substances, the repeated use of animals and the reduction of the number of animals.

Animals↗
PubMed2004

[Experimental hemorheology study on group a whole blood added with group O whole blood].

The study was to investigate the hemorheologyic changes of group A blood recipient transfused with large amounts of group O whole blood, by erythrocyte count, sympexis index, erythrocyte deformation index, erythrocyte rigid index and whole blood reduced viscosity, 60 ml of group A whole blood were added with 9, 12, 15 and 18 ml of group O whole blood (which corresponds to the 4 000 ml whole blood added with 600, 800, 1 000 and 1 200 ml whole blood). The mixed blood was incubated at 37 degrees C with mixing at 80 times per minute. Samples were taken from the mixed blood at 30 minutes, 2, 4, 8, 12 and 24 hours after culture, and the hemorheology of the mixed whole blood was determined by FASCO-series type 3020B automatic rheograph apparatus. The results showed that there were no differences of erythrocyte count, sympexis index, erythrocyte deformation index, erythrocyte rigid index and whole blood reduced viscosity among all different kinds of mixed whole blood, and there was no difference of sympexis index at different times, but there were obvious differences of erythrocyte count, erythrocyte deformation index, erythrocyte rigid index and whole blood reduced viscosity. It is concluded that blood transfusion of 1,200 ml group O whole blood to a recipient with 50 kg of body weight but with different blood type in emergent situation may exert no harm to the erythrocytes of recipient in a short term.

ABO Blood-Group System↗
PubMed1994

Hemoglobin blood substitutes in extended preoperative autologous blood donation: an experimental study.

BACKGROUND: The risks of homologous blood transfusion have stimulated interest in developing possible alternatives. In this study we examined the efficacy of using a hemoglobin-derived blood substitute to augment and extend preoperative autologous blood donation. METHODS: In an ovine model, two experimental groups (n = 6 each) of animals donated either 45% or 80% or more of calculated blood volume, which was replaced with a polymerized bovine hemoglobin solution. Two control groups (n = 6 each) either did not donate or donated 45% of calculated blood volume, which was replaced with a 6% hetastarch solution. Twenty-four hours after blood donation, sheep underwent a measured surgical stress with standardized intraoperative blood loss; donated blood was reinfused. RESULTS: Extended autologous blood donation and replacement with this blood substitute were efficacious in supporting oxygen consumption; there was no systemic toxicity. After the postoperative replacement of autologous blood, animals that donated 80% or more of red cell mass exhibited overall blood conservation with a final hematocrit of 25.7% +/- 3.6%, compared with 20.5% +/- 2.0% (p < 0.05) and with 21.5% +/- 1.1% (p < 0.05) in both control groups. CONCLUSIONS: This study suggests that the benefits of a blood substitute can be combined with autologous blood donation to (1) safely increase the amount of autologous blood donated while supporting oxygen consumption, (2) avoid the need for advanced preoperative donation, and (3) decrease the need for homologous blood transfusion.

Animals↗