Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BLOOD”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1994

The impact of autologous blood ordering and blood procurement practices on allogeneic blood exposure in elective orthopedic surgery patients.

The contribution of autologous blood ordering and blood procurement practices on subsequent allogeneic blood exposure in elective orthopedic surgery must be understood to address the role of aggressive autologous blood procurement in blood conservation strategies. The authors examined the relationship between autologous blood ordering, blood collection, and subsequent allogeneic blood transfusion in orthopedic surgical patients. Of 263 consecutive autologous blood donors reviewed, 179 (68%) successfully donated the number of units requested (blood ordering cohort). Of these, 17 (9.5%) received allogenic blood. Of 84 patients unable to donate the units requested, 23 (27%) received allogeneic blood (blood procurement cohort). Allogeneic blood exposure in the blood ordering cohort occurred at the same prevalence for patients asked to donate < or = 3 units or > or = 4 units (10[6.8%] of 146 patients and 7[6%] of 116 patients, respectively). In contrast, only 3 (2%) of 146 patients asked to donate < or = 3 units received allogeneic blood in the blood procurement cohort, compared with 20 (17%) of 116 patients asked to donate > or = 4 units (P < .01). The greatest prevalence of allogeneic blood exposure occurred in 13 (35%) of 37 anemic (hematocrit level 39% at first donation) patients in the blood procurement cohort who could not donate > or = 4 units as requested. The study indicated that both blood ordering and blood procurement practices in autologous blood donation programs are important factors in blood conservation efforts to minimize allogeneic blood exposure.

Adult↗
PubMed2000

Differences between blood flow as indicated by the hemodialysis blood roller pump and blood flow measured by an ultrasonic sensor.

BACKGROUND/AIM: The ultrasonic transit time is currently the best method for measuring the blood flow rate in the extracorporeal hemodialysis circuit. The purpose of this study was to analyze the differences between blood flow as indicated by the hemodialysis blood roller pump (prescribed blood flow) and by an ultrasonic flowmeter (delivered blood flow). METHODS: The ultrasonic blood flow was measured in 20 patients on chronic hemodialysis who were dialyzed through an arteriovenous fistula. During each dialysis session the ultrasonic blood flow was measured at three different blood roller pump flow rates (300, 350, and 400 ml/min). In order to analyze the influence of inflow and outflow pressures on blood flow, this study was conducted during nine consecutive dialysis sessions during which needles of different sizes were used. RESULTS: The ultrasonic flow was always lower than indicated by the blood roller pump: 265+/-12, 304+/-15, and 341+/- 19 ml/min for blood roller pump flow rates of 300, 350, and 400 ml/min, respectively (variability: -11.6, -13.1, and -14.8%, respectively). An univariate regression analysis showed that the reduction in flow recorded ultrasonically correlated with both venous blood line pressure (r = -0.2679, p<0.001) and negative arterial blood line pressure (r = 0. 6773, p<0.001). By multivariate analysis, only the arterial blood line pressure has a predictive value. When all measurements were grouped by arterial blood line pressure ranges, the variability between ultrasonic blood flow and blood roller pump flow was found to be similar in those groups with the same arterial blood line pressure, regardless of the blood roller pump flow rate. CONCLUSIONS: The blood flow indicated by the dialysis blood roller pump is always greater than the delivered blood flow, and this difference is in turn conditioned by the negative pressure induced by the blood roller pump in the arterial blood line.

Blood Flow Velocity↗
PubMed2003

The use of peridialysis blood pressure and intradialytic blood pressure changes in the prediction of interdialytic blood pressure in haemodialysis patients.

OBJECTIVE: It is uncertain which blood pressure values (pre- or post-haemodialysis) best represent the average daily blood pressure in haemodialysis patients. The purpose of this study was to verify the power of peridialysis blood pressure to predict interdialytic blood pressure, and to ascertain the influence of blood pressure fluctuations during dialysis on this predictive ability. METHODS AND RESULTS: We performed ambulatory blood pressure monitoring during the interdialytic period on 60 stable haemodialysis patients (mean age 53 +/- 16 years, 33 male) between two mid-week haemodialysis sessions. Pre- and post-haemodialysis blood pressures were 154/82 and 142/77 mmHg, respectively, and 44-h interdialytic blood pressure was 136/77 mmHg. Overall, post-haemodialysis blood pressure values correlated with interdialytic ambulatory blood pressure marginally better than did pre-haemodialysis values (r = 0.52 versus 0.61 for pre- and post-dialysis systolic pressure, respectively; r = 0.67 versus 0.72 for pre- and post-dialysis diastolic pressure, respectively). The average of the pre- and post-haemodialysis values showed a slightly better correlation with interdialytic blood pressure (r = 0.65 and 0.75 for systolic and diastolic pressure, respectively). When we stratified patients according to systolic blood pressure behaviour during dialysis, pre-dialysis blood pressure was the stronger predictor of interdialytic blood pressure in the quartile with greatest intradialytic blood pressure fall (r = 0.67 versus 0.44 for pre- and post-dialysis systolic blood pressure, respectively), whereas post-dialysis values were substantially better in the group with a rise in systolic pressure during dialysis (r = 0.26 versus 0.59 for pre- and post-dialysis systolic blood pressure, respectively). CONCLUSIONS: These data demonstrate that peridialysis blood pressure values are of limited accuracy in predicting interdialytic blood pressure, post-dialysis values are minimally better predictors than pre-dialysis blood pressures, and the average of pre- and post-haemodialysis values is marginally better than both. In addition, blood pressure fluctuations during dialysis have a sizable impact on this predictive ability. Clinical decisions related to blood pressure management and research design in haemodialysis hypertension should take these factors into account.

Blood Pressure↗
PubMed2006

Effects of cell saver autologous blood transfusion on blood loss and homologous blood transfusion requirements in patients undergoing cardiac surgery on- versus off-cardiopulmonary bypass: a randomised trial.

OBJECTIVE: Off-pump CABG is potentially associated with reduced intraoperative blood loss and homologous blood transfusion in comparison to on-pump CABG. In this randomised controlled study we investigated the effects of autologous cell saver blood transfusion on blood loss and homologous blood transfusion requirements in patients undergoing CABG on- versus off-CPB. METHODS: Eighty patients were randomised into one of four groups: (A) on-CPB with cell saver blood transfusion (CSBT), (B) on-CPB without CSBT, (C) off-pump with CSBT and (D) off-pump without CSBT. Volume of intraoperative autologous blood transfusion, postoperative mediastinal blood loss and homologous blood transfusion requirements were measured. Homologous blood was transfused when haemoglobin concentration fell below 8 g/dl postoperatively. Pre- and postoperatively prothrombin time and partial thromboplastin time were measured. RESULTS: Preoperative patient characteristics were well matched among the four groups. The amount of salvaged mediastinal blood available for autologous transfusion was significantly higher in the on-pump group (A) compared to the off-CPB group (C) (433+/-155 ml vs 271+/-144 ml, P=0.001). Volume of homologous blood transfusion was significantly higher in group B vs groups A, C and D (595+/-438 ml vs 179+/-214, 141+/-183 and 230+/-240 ml, respectively, P<0.005). The cell saver groups (A and C) received significantly less homologous blood than the groups without cell saver (160+/-197 ml vs 413+/-394 ml, respectively, P<0.005). Patients undergoing off-CPB surgery received significantly less homologous blood than those undergoing on-CPB CABG irrespective of cell saver blood transfusion (184+/-214 ml vs 382+/-397 ml, P<0.05). Postoperative blood loss was similar in the four groups (842+/-276, 1023+/-291, 869+/-286 and 903+/-315 ml in groups A to D, respectively, P>0.05). Clotting test results revealed no significant difference between the groups. There was no significant difference in postoperative morbidity between groups. CONCLUSION: Off-pump CABG is associated with significant reduction in intraoperative mediastinal blood loss and homologous transfusion requirements. Autologous transfusion of salvaged washed mediastinal blood reduced homologous transfusion significantly in the on-CPB group. Cell saver caused no significant adverse impact on coagulation parameters in on- or off-CPB CABG. Postoperative morbidity and blood loss were not affected by the use of CPB or autologous blood transfusion. We recommend the use of autologous blood transfusion in both on- and off-pump CABG surgery.

Aged↗
PubMed1980

Separation of blood cells from normal blood and blood of patients with various malignant blood diseases using separation media.

Differential counts of normal and leukemic cells separated from human peripheral blood were compared using three different separation media a) Verografin, b) Verografin-Ficoll, c) Isopaque-Ficoll (Lymphoprep), density 1.077 g/ml. In the separation the solution of Verografin (SPOFA) or Verografin-Ficoll yields analogous cell counts to Isopaque-Ficoll solution. The separation of leukemic cells is similar on all three separation media with considerable packing of some cells of the myeloid line. The blood cells separated from peripheral blood of normal donors on three various separation media correlate also in T and B lymphocyte counts, as demonstrated by the results of E and EAC rosette tests.

Cell Separation↗
PubMed2003

Fasting blood glucose is independently associated with resting and exercise blood pressures and development of elevated blood pressure.

OBJECTIVE: To assess whether fasting blood glucose is independently related to blood pressure at rest and during exercise, and to development of elevated blood pressure. DESIGN: Cross-sectional and prospective cohort study of 2014 apparently healthy middle-aged men. METHODS: The baseline survey included carefully standardized blood pressure measurements at rest and during exercise testing, an intravenous glucose tolerance test and a panel of fasting blood tests, including fasting blood glucose. Results from 7-years follow-up provided data on development of elevated blood pressure. RESULTS: Strong associations were found between quartiles of fasting blood glucose and baseline resting and/or exercise levels of blood pressure, and also development of elevated blood pressure over 7 years. Physical fitness, calculated from an exercise test, had a strong modulating effect on blood pressure at all levels of fasting blood glucose. In multivariate models - after adjusting for intravenous glucose tolerance, physical fitness, age, body mass index, triglycerides and cholesterol - fasting blood glucose was strongly associated with blood pressure at rest (coefficient = 2.83, P = 0.0004) and during exercise (coefficient = 6.57, P < 0.0001), and further to development of treated hypertension and/or elevated blood pressure [odds ratio (OR), 1.17; 95% confidence interval (CI), 1.05-1.31]. CONCLUSION: In healthy non-diabetic and non-hypertensive men, strong associations were found between fasting blood glucose and blood pressure at rest and during exercise and to development of elevated blood pressure after 7-years follow-up. Fasting glucose metabolism deserves scrutiny when studying the pathogenesis of hypertension.

Adult↗
PubMed1998

Rheological properties and function of blood cells in stored bank blood and salvaged blood.

The technique involving filtration of diluted blood enables the separate analysis of the flow properties of different cell subpopulations. This study was designed to assess the changes occurring in the flow properties and function of blood cells in stored bank blood and salvaged blood compared to patient blood in a given clinical situation. We measured hydrogen peroxide production by neutrophils and the filterability, through 5 microm Nucleopore filters, of isolated red blood cells and of diluted blood. Samples were obtained from patients undergoing aortic surgery and blood intended for transfusion: either salvaged during surgery or stored bank blood. Both salvaged and bank blood were much less filterable than patient blood, with reduced deformability of both red and white blood cells. However, salvaged blood contained highly activated neutrophils with a prolonged transit time of the 'fast-flowing' cells in the analysis compared to bank blood. Bank blood contained significantly more particles which acted as pore-blockers. Cells in bank and salvaged blood therefore have markedly abnormal flow and biochemical properties compared to patient blood.

Blood Banks↗
PubMed1989

[Blood routine tests in capillary blood compared to those of venous blood].

When the venipuncture is difficult, should the blood routine tests be performed on capillary blood? Are there any differences in blood routine tests between capillary blood and venous blood? Many studies have been made of infants before our study, but there are few studies of adults. For the purposes of this study, we compared blood routine tests in capillary blood with those of venous blood in adults. Capillary blood and venous blood were drawn at the same time from 50 adults to estimate the values of blood routine tests. Specifically, blood specimens were drawn to estimate RBC, WBC, Hb, Hct, MCV, MCH and MCHC values by coulter counter model S7, while platelet value was estimated by ULTRA FLO 100. The results are presented follows: (1) The differences are non-significant in RBC, WBC, Hb and MCH between the venous blood [453.74 +/- 85.4) x 10(4)/cmm, 8290 +/- 4074/cmm 13.53 +/- 2.42 (gm%), 30.23 +/- 2.55 (pg] and the capillary blood [463.14 +/- 94.57) x 10(4)/cm 8182 +/- 4268/cm, 13.82 +/- 2.61 (gm%), 30.12 +/- 2.21 (pg]. p greater than 0.05. (2) The values of the Hct and MCV in capillary blood (44.02 +/- 7.78 (%), 95.34 +/- 7.33 (fl] are significantly higher than those of venous blood (40.64 +/- 6.83 (%), 89.94 +/- 6.94 (fl]. p less than 0.05. (3) The values of the platelet and MCHC in venous blood (29.29 +/- 10.5) x 10(4)/cmm, 33.17 +/- 1.09 (%] are significantly higher than those of capillary blood (18.44 +/- 8.1) x 10(4)/cmm, 31.38 +/- 1.01 (%]. p less than 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

Capillaries↗
PubMed2000

Postoperative blood salvage and reinfusion in spinal surgery: blood quality, effectiveness and impact on patient blood parameters.

Although reinfusion of salvaged shed blood has become popular in major orthopaedic procedures, this blood saving technique is still controversial. In an effort to assess the functional and metabolic status of shed blood erythrocytes and the impact of postoperative shed blood reinfusion on allogenic blood requirements and patient's blood parameters, analyses of perioperative blood samples were performed in 28 consecutive orthopaedic patients undergoing spinal fusion, in which postoperative shed blood was collected and reinfused with the ConstaVac CBC II device. In comparison with a previous series of 31 patients, this procedure reduced allogenic blood requirements by almost 30% (P < 0.05), without any increase in postoperative complications. Postoperative shed blood presented lower haematological values and higher plasma-free haemoglobin (PFHB) levels than preoperative blood, without any disturbance in morphology, median corpuscular fragility (MCF) or erythrocyte adenosine triphosphate (ATP) and diphosphoglycerate (DPG) content. Serum concentrations of enzymes--glutamate-oxalacetate aminotransferase (GOT), glutamate-piruvate aminotransferase (GPT), creatine kinase (CK), lactate dehydrogenase (LDH)--and inflammatory cytokines (IL-1beta, IL-6) were elevated in shed blood. After reinfusion, there was no alteration in coagulation parameters or cytokine levels. Serum levels of some enzymes increased at the end of surgery and remained elevated at postoperative day 2 (CK) or 7 (GOT, LDH), with a higher increase if postoperative autotransfusion was used as a blood saving method. Therefore, caution should be taken when these serum enzyme levels are used for diagnosis. In conclusion, salvaged shed blood in orthopaedic procedures of the spine seems to be an excellent source of red cells which are not significantly damaged, keeping a normal functional and metabolic status, and reduces allogenic blood requirements without significant side effects.

Blood Cell Count↗
PubMed1998

Normal values for ambulatory blood pressure and differences between casual blood pressure and ambulatory blood pressure: results from a Danish population survey.

OBJECTIVE: To determine normal values for 24 h ambulatory blood pressure in a Danish population and to study the relationship to casual blood pressure. STUDY POPULATION: A random sample of 2656 Danish men and women participated in a population survey. The participants were selected in age groups and were aged 41-42, 51-52, 61-62 or 71-72 years during the survey. METHODS; Casual blood pressure (standard mercury sphygmomanometer) and 24 h ambulatory blood pressure (Takeda TM-2421) were measured successfully in 2082 subjects. All subjects under antihypertensive treatment (247) were excluded, restricting the study population to 1835 participants. RESULTS: Casual and 24 h ambulatory blood pressure were correlated (P < 0.0001) in all age and sex groups. Casual systolic/diastolic blood pressures were 129.6+/-17.8/82.6+/-10.3 for men and 125.1+/-18.2/79.7+/-9.9 mmHg for women. Twenty-four-hour average blood pressures were 130.8+/-14.2/75.3+/-8.6 for men and 122.4+/-14.9/69.6+/-8.3 mmHg for women. A multivariate linear logistic regression model confirmed that a high casual blood pressure (odds ratios 11/7 for systolic/diastolic blood pressure; P=0.001) was the major determinant of a lower ambulatory than casual blood pressure; age and sex were less important. CONCLUSION: The relationship between casual blood pressure on the one hand and the difference in casual and 24 h ambulatory blood pressure on the other hand suggests that ambulatory blood pressure represents a regression towards the mean compared to casual blood pressure. Any definition of an upper normal level of 24 h ambulatory blood pressure that is derived from a correlation between casual and ambulatory measurements will be inaccurate, and must await long-term studies of the relationship between ambulatory blood pressure and subsequent cardiovascular events.

Adult↗
PubMed2006

The effect of repeated blood donations on the iron status of Iranian blood donors attending the Iranian blood transfusion organization.

OBJECTIVE: Blood donation leads to substantial iron loss, as about 0.5 mg iron is lost per each milliliter of blood donated. If not compensated for efficiently, the iron loss may eventually lead to anemia, though non-anemic iron deficiency per se may be problematic. The aim of this study was to evaluate the effects of blood donation, and its frequency over a year's time, on iron status of Iranian male blood donors attended blood transfusion stations of the Iranian Blood Transfusion Organization (IBTO). DESIGN AND SETTING: A cross-sectional, descriptive, and analytic study was conducted. 91 male volunteer blood donors aged from 20 to 50 years attending three IBTO stations located in central areas of Tehran, and 63 apparently healthy controls that were matched for age, gender, monthly income, height, and weight, were included in the study. Blood donors were divided into 4 groups according to the frequency of blood donation per year; i.e. 1, 2, 3, and 4 with 20, 30, 26, and 15 persons in each group, respectively. Just before blood donation, 10 mL venous blood sample was taken and divided into heparinized and non-heparinized tubes for determination of hemoglobin (Hb), hematocrit (Hct), serum iron (SI), total iron binding capacity (TIBC), ferritin, transferrin saturation (TS), and mean corpuscular hemoglobin concentration (MCHC). Dietary assessment was also done using 3 different questionnaires; i.e. general health, food frequency, and 24hr recall. RESULTS: The levels of Hb, Hct, and iron status indices were all significantly lower in the subjects than in controls and a gradual but significant decrease in iron status indices in each time of blood donation was found. Serum ferritin showed significant correlations with age (r = 0.33, p < 0.001) and body-mass index (BMI) (r = 0.26, p = 0.03) only in the control group. Frequency of blood donation per year was also inversely correlated with Hb (r = -0.67, p < 0.001), Hct (r = -0.65, p < 0.001), MCHC (r = -0.56, p < 0.001), serum ferritin (r = -0.38, p < 0.001), SI (r = -0.62, p < 0.001), and TS (r = -0.61, p < 0.001), but was directly correlated with TIBC (r = 0.56, p < 0.001). Interestingly in blood donors, but not in healthy controls, serum ferritin levels showed weak but statistically significant correlations with daily intake of iron (r = 0.17, p < 0.05) and energy (r = 0.20, p = 0.03). CONCLUSION: Though repeated blood donations might diminish iron status, it could be safe to donate 2-3 U/year without an appreciable incidence of iron deficiency, provided that the pre-donation Hb and ferritin values are >/= 14.7 g/dL and 58.9 mug/L, respectively. The male volunteers with Hb >/= 14.2 g/dL and serum ferritin >/= 57.2 mug/L could donate 1-2 U/year and those with Hb >/= 13.1 g/dL and serum ferritin >/= 35.3 mug/L could donate just once a year. Volunteers who undergo (repeated) blood donation should receive special nutritional care, especially in terms of iron and energy.

Adult↗
PubMed2005

Development of a new method for monitoring blood purification: the blood flow analysis of the head and foot by laser Doppler blood flowmeter during hemodialysis.

The management of blood pressure in hemodialysis patients greatly affects not only their quality of life, but also the duration of dialysis (dialysis life). Approximately 25% of dialysis patients suffer from continuous low blood pressure; however, the relationship between blood pressure and blood flow during dialysis has not been established. We hypothesized that with complete extracorporeal circulation, blood purification methods might affect blood flow, resulting in a change in blood pressure. The purpose of this study was to develop a noninvasive continuous monitoring method (NICOMM) as a microcirculation monitor by devising a laser-Doppler flowmeter (LDF) system with a wavelength of 780 nm. The aim was to use this system to simultaneously measure blood flow rate in both the head and the foot during dialysis and to determine the effectiveness of NICOMM by measuring blood flow and arterial distensibility. When exhibiting a significant decline in blood pressure at 240 min after the initiation of hemodialysis, a drop in blood flow in parallel with the blood pressure fall was recorded by the LDF. However, no changes were observed, in the readings by a continuous hematocrit monitor (Crit-Line monitor, CLM). Furthermore, a significant correlation was registered between mean arterial blood pressure and blood flow rate in the earlobe tissue from 180 min after the initiation of hemodialysis to the completion of hemodialysis (p < 0.001, r = 0.78). Comparisons were made by measuring vascular dehydration using the CLM. NICOMM showed more stable readings than the CLM in monitoring blood flow in response to changes in blood pressure.

Blood Pressure↗
PubMed2001

Assessment of blood pressure in patients with Type 2 diabetes: comparison between home blood pressure monitoring, clinic blood pressure measurement and 24-h ambulatory blood pressure monitoring.

AIMS: To compare a home blood pressure (BP) monitoring device and clinic BP measurement with 24-h ambulatory BP monitoring in patients with Type 2 diabetes mellitus (DM). METHODS: Fifty-five patients with type 2 DM had BP measured at three consecutive visits to the DM clinic by nurses using a stethoscope and mercury sphygmomanometer (CBP). Twenty-four-hour ambulatory BP was measured using a Spacelabs 90207 automatic cuff-oscillometric device (ABPM). Subjects were then instructed in how to use a Boots HEM 732B semiautomatic cuff-oscillometric home BP monitoring device and measured BP at home on three specified occasions on each of 4 consecutive days at varying times (HBPM). RESULTS: Correlations between HBPM and ABPM were r = 0.88, P < 0.001 for systolic BP and r = 0.76, P < 0.001 for diastolic BP, with correlations between CBP and ABPM being systolic r = 0.59, P < 0.001, diastolic r = 0.47, P < 0.001. HBPM agreed with ABPM more closely compared with CBP (CBP +10.9/+3.8 (95% confidence intervals (CI) 6.9, 14.8/1.6, 6.1) vs. HBPM +8.2/+3.7 (95% CI 6.0, 10.3/2.0, 5.4)). The sensitivity, specificity and positive predictive value of HBPM in detecting hypertension were 100%, 79% and 90%, respectively, compared with CBP (85%, 46% and 58%, respectively). CONCLUSIONS: In patients with Type 2 DM, home BP monitoring is superior to clinic BP measurement, when compared with 24-h ambulatory BP, and allows better detection of hypertension. It would be a rational addition to the annual review process. Diabet. Med. 18, 431-437 (2001)

Adult↗
PubMed2003

Reducing unnecessary cross-matching: a patient-specific blood ordering system is more accurate in predicting who will receive a blood transfusion than the maximum blood ordering system.

UNLABELLED: Most blood transfusions are given in the operating room. Adoption of the Maximum Surgical Blood Ordering Schedule in the 1970s reduced the amount of blood unnecessarily cross-matched, but the national cross-match-to-transfusion ratio remains at approximately two-to-one. We tested the ability of a patient-specific blood ordering system (PSBOS) to more accurately predict potential operative transfusion. All adult patients who had blood cross-matched before surgery (February through June 1999) for elective operative procedures at the University of Michigan Hospital were identified. Complex surgeries were excluded. Surgeons estimated the expected blood loss for their surgeries, and the expected postoperative hematocrit was calculated using the patient's blood volume, the surgeon-defined expected blood loss, and preoperative hematocrit. Lowest tolerated hematocrit was set at 21% except in patients with coronary artery disease or who were ASA physical status III or more (28%). Sensitivity, specificity, positive predictive value, and negative predictive value of the PSBOS were calculated. Our analysis included 178 cases in which blood was cross-matched before surgery, representing 69 different surgeries and 42 surgeons. Only 16% of patients received an intraoperative transfusion. Of the 156 patients that PSBOS predicted would not require an operating room transfusion, 139 were not transfused. Of the 21 patients PSBOS predicted would be transfused, 11 were. The sensitivity of the algorithm as tested was 41%, the specificity 93%, the positive predictive value was 55%, and the negative predictive value was 89%. We conclude that PSBOS, which includes patient and surgeon variables in transfusion prediction, is more accurate than the Maximum Surgical Blood Ordering Schedule, which uses only surgical procedure. IMPLICATIONS: Currently, many units of blood set aside for surgery are never required, resulting in extra work and expense for blood banks. A formula that included patient weight and hematocrit and typical surgery blood loss was used to predict who would require transfusions. We reduced the predicted number of patients who had blood set aside from 178 to 21.

Adolescent↗
PubMed2001

Lack of hypercapnic increase in cerebral blood flow at high blood viscosity in conscious blood-exchanged rats.

BACKGROUND: The hypothesis of a compensatory dilation of cerebral vessels to maintain cerebral blood flow at a high blood viscosity was tested during hypercapnia in the study after replacement of blood by hemoglobin solutions of defined viscosities. If compensatory vasodilation exists at normocapnia at a high blood viscosity, vasodilatory mechanisms may be exhausted when hypercapnia is added, resulting in a lack of increase in cerebral blood flow at hypercapnia. METHODS: In conscious rats, blood was replaced by ultrapurified cross-linked hemoglobin solutions that had defined and shear rate-independent low or high viscosities (low- and high-viscosity groups). Blood viscosity differed threefold between both groups (1.2 vs. 3.6 mP x s). Thereafter, rats inhaled either a normal or an increased concentration of carbon dioxide in air. Cerebral blood flow was determined by the iodo[14C]antipyrine method. RESULTS: During normocapnia, global and local cerebral blood flows did not differ between both groups. With increasing degrees of hypercapnia, global and local cerebral blood flows were gradually elevated in the low-viscosity group (2.8 ml x mmHg(-1) CO2 x 100 g(-1) x min(-1)), whereas they remained unchanged in the high-viscosity group. CONCLUSIONS: Changes in blood viscosity do not result in changes of cerebral blood flow as long as cerebral vessels can compensate for these changes by vasodilation or vasoconstriction. However, such vascular compensatory adjustments may be exhausted in their response to further pathophysiologic conditions in blood vessels that have already been dilated or constricted as a result of changes in blood viscosity.

Animals↗
PubMed1997

Whole blood viscosity, blood pressure and cardiovascular risk factors in healthy blood donors.

Whole blood viscosity contributes to the total peripheral resistance and has been suggested to be a risk factor for cardiovascular disease. Whole blood viscosity was measured using a direct technique in 105 healthy blood donors and in addition to establishing our reference values, the relationship to blood pressure and other cardiovascular risk factors was assessed. Whole blood viscosity correlated with systolic blood pressure (r = 0.29, p = 0.003), cholesterol (r = 0.21, p = 0.034), cholesterol/HDL cholesterol ratio (r = 0.33, p = 0.01), triglycerides (r = 0.37, p < 0.0005), body mass index (r = 0.29, p = 0.003) and waist-hip ratio (r = 0.30, p = 0.002). Subjects with systolic blood pressure > 130 mmHg (n = 16) had higher whole blood viscosity (p = 0.017) than those with lower blood pressure. Whole blood viscosity was significantly lower in women (n = 52) than in men at all shear rates (0.045 > p > 0.001). These results suggest that even in a population of healthy normotensive blood donors of a wide age range and either gender, there are positive correlations between directly assessed whole blood viscosity and a number of the components of the metabolic cardiovascular syndrome including systolic blood pressure, weight and blood lipids.

Adult↗
PubMed1999

Superficial blood flow, blood volume, and blood velocity in colorectal tubular adenomas and adenocarcinomas.

To clarify differences in the vasculature of benign and malignant colorectal tumors, we compared blood flow (which has been examined in previous studies) as well as blood volume and blood velocity in two types of human colorectal tumors. We measured blood flow and blood volume with an endoscopic laser-Doppler flowmeter in the lesions and the normal mucosa near the lesions of 79 tubular adenomas with mild dysplasia and 38 adenocarcinomas. Blood velocity was defined as blood flow per blood volume. The ratio of each value in the lesions to that in the neighboring normal mucosa was defined as the relative value, and the mean relative values in the two groups were compared. The relative blood flow was 1.89 +/- 0.64 in the tubular adenomas and 1.49 +/- 0.66 in the adenocarcinomas (P < 0.005), and the relative blood volume was 1.10 +/- 0.14 and 0.90 +/- 0.13, respectively (P < 0.001). The relative blood velocity was approximately 1.7 in both groups (NS). This study demonstrated that the superficial blood flow in adenocarcinomas is increased due to increased blood velocity, despite blood volume being decreased.

Adenocarcinoma↗