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PubMed1988

Effect of smoke inhalation injury on thromboxane levels and platelet counts.

Thirteen goats with chronic lung lymph fistula suffering from smoke inhalation injury were studied for a 6-h period. All animals were found to have acute respiratory failure after injury, the arterial TXA2 (thromboxane A2) levels had increased by 5 min after injury, they peaked at 2 h, and then subsequently declined. Peripheral platelet counts decreased progressively within 2 h, then gradually recovered but were still lower than baseline values at 6 h after injury. EVLW (extravascular lung water), Q1 (lung lymph flow rate) and L/P (total lymph protein/plasma protein concentration), all increased and peaked at 2 h after injury. A negative linear correlation was observed between the TXA2 levels and the platelet counts. Furthermore, differences between the venous and arterial platelet counts were markedly increased. All these observations suggested that the increased TXA2 triggered the formation of platelet microaggregates which were then trapped in the microvasculatures of viscera such as the lung. This might be one of the causes of the decreased platelet counts in peripheral blood. Both TXA2 levels and platelet counts were closely correlated with EVLW, suggesting that TXA2 may indirectly cause the increased pulmonary microvascular permeability by promoting platelet aggregation and microaggregate formation in the pulmonary microvasculature. This may be one of the reasons for the developing pulmonary oedema in goats following smoke inhalation injury.

Animals↗

PubMed1996

[Amrinone administration exerts no deleterious effect on platelet counts and blood transfusion volume during CABG].

The purpose of this study was to examine retrospectively the effect of amrinone on platelet counts and blood transfusion volume during CABG. Patients were divided into two groups. Amrinone group included 40 patients and for comparison another group included 33 patients who had undergone CABG without amrinone. Anesthesia and surgical procedures were standardized and similar for all patients. Platelet counts and hematocrit levels were measured in the arterial blood before CPB, at the end of CPB (after treatment with amrinone in amrinone group), 1 day, 3 days, and 7 days after surgery. Time course of changes in platelet counts was the same between the groups at the following points: before CPB, after CPB, 1 day, 3 days, and 7 days after surgery. We administered amrinone to patients who underwent CABG. The titrated dose of amrinone (about 29mg.kg-1) has not affected the time course of changes in platelet counts and blood transfusion volume.

Aged↗

PubMed2005

Analysis of outcome of laparoscopic splenectomy for idiopathic thrombocytopenic purpura by platelet count.

Laparoscopic splenectomy (LS) is now performed routinely in patients with idiopathic thrombocytopenic purpura (ITP) refractory to the medical treatment. Low preoperative platelet count was deemed to be a contraindication for a laparoscopic approach; however, there is no data reporting the outcome in those patients. We aimed to evaluate the influence of the preoperative platelet count on the operative and postoperative course and complication rate. Retrospective cohort study that was conducted in tertiary care university-affiliated medical center and included 110 consecutive patients who underwent LS. All patients were divided into three groups by their preoperative platelet counts: 50 x 10(9)/L (n = 80). The outcome and the influence of preoperative factors predictive of complications, blood transfusion, and length of stay were compared between the groups. Patients with a platelet count of 20 x 10(9)/L before surgery. Patients with counts >20 x 10(9)/L can safely undergo LS.

Blood Transfusion↗

PubMed1988

Effect of dipyridamole on blood glucose and liver cyclic AMP levels and platelet count during endotoxaemia in mice.

1. Blood glucose, liver cyclic AMP (cAMP) levels, and platelet count were studied at different times during a 12 h interval after intravenous (i.v.) endotoxin injection (40 mg/kg) in mice. 2. Blood glucose and liver cAMP levels showed a progressive decrease in endotoxic mice and the decrease was significant after 8 and 12 h. 3. Dipyridamole (50 mg/kg) administered intraperitoneally (i.p.) 7 h post-endotoxin improved blood glucose and liver cAMP levels. 4. Platelet counts were decreased after 1 h in endotoxic mice and remained decreased up to 8 h. Dipyridamole administered soon after endotoxin improved platelet counts in endotoxic mice and increased survival rate to 100%.

Animals↗

PubMed2006

Measuring the concerns of cancer patients with low platelet counts: the Functional Assessment of Cancer Therapy--thrombocytopenia (FACT-Th) questionnaire.

PURPOSE: The specific concerns of people with low platelet counts (thrombocytopenia) have not been characterized well in the literature and as a result proper measurement of patient-reported concerns is lacking. We report on the development and validation of questions specifically targeted to patients with thrombocytopenia that can be added to the more general concerns in the Functional Assessment of Cancer Therapy-General. MATERIALS AND METHODS: An 18-item FACT-Thrombocytopenia Subscale (ThS) was rated and evaluated by thrombocytopenic patients at baseline during a validation study of 40 thrombocytopenic and 43 nonthrombocytopenic cancer patients. To evaluate responsiveness, patients completed a battery of self-report measures including the FACT-Th and were followed up for change in platelet count over 2 weeks. RESULTS: All subscales and aggregated scores showed high internal consistency at initial assessment and at retesting. Convergent and divergent validity were demonstrated by predicted relationships between FACT-Th subscales and mood, mental and physical component scores of the SF-36, and social desirability. The ThS differentiated patients with low platelets from those with normal platelet counts and good performance from poor performance status patients. CONCLUSION: The FACT-Th is a reliable and valid measure for assessing the impact of thrombocytopenia on patients' lives. It can distinguish cancer patients with and without thrombocytopenia and is responsive to increase in platelet count over time. The FACT-Th may therefore prove useful as a measure of self-reported symptoms and concerns related to thrombocytopenia in clinical trials evaluating new pharmacologic agents and/or platelet transfusion practice.

Adult↗

PubMed1981

Automated platelet counting--a re-evaluation of the sedimentation method.

Platelet counting by means of the Coulter Thrombocounter, using the Thrombofuge method for specimen preparation has been evaluated in order to determine the cause of discrepancies in results obtained in interlaboratory quality assessment surveys. The method was assessed for accuracy, precision, drift and carry-over. When the method was used, as in routine practice, some discrepancies occurred; an important source of error was identified as being due to the level of sedimented plasma layer from which samples are removed. When the method was performed strictly in accordance with the manufacturer's instructions results were generally satisfactory and comparable to those obtained with the whole blood reference method, although, even with this standardized technique, the Thrombo-fuge tended to give higher platelet counts than the reference method with counts above 200 X 10(9)/l. This discrepancy to be independent of PCV, MCV or other identifiable factors.

Blood Platelets↗

PubMed1996

Estimation of the lower limits of manual and automated platelet counting.

Most evaluators of automated or manual methods for platelet counting focus on characteristics such as imprecision, linearity, and carry over. The limits of the analytical procedure are usually not assessed. The limits of the different techniques are neither discussed in the literature nor do manufacturers of analytical systems supply these data. A new procedure is presented to assess the performance of the manual as well as the automated platelet count. This procedure allows, with defined statistical confidence (eg, 95%), the determination of (1) the limit of platelet detection (LD) at which signals of platelets can be discriminated from the system noise; (2) the lower limit of quantification (LLQ), at which a certain imprecision is not surpassed; and (3) the power of definition (PD) that defines the number of values that can be discriminated in a certain interval. For each value, the PD allows calculation of the two adjacent (lower and higher) values that are significantly (P > or = 0.95) different. For the manual count, LD was found to be 1.6 x 10(9) plt/L and the LLQ 6.9 x 10(9) plt/L. For the automated count with the Technicon H1, LD was 4.3 x 10(9) plt/L and LLQ 13.8 x 10(9) plt/L (CVmax = 15%). The PD in the range 20 to 100 x 10(9) plt/L is 8 for the automated and 7 for the manual count.

Analysis of Variance↗

PubMed2001

Serum aminotransferase levels and platelet counts as predictors of degree of fibrosis in chronic hepatitis C virus infection.

OBJECTIVE: In patients with chronic hepatitis C virus (HCV) infection, liver fibrosis stage is a prognostic factor for therapy outcome. So far, a liver biopsy is necessary to determine disease stage accurately. We sought to develop a simple, noninvasive method of accurately predicting the degree of liver fibrosis in chronic HCV infection. METHODS: We retrospectively studied 211 consecutive patients with chronic HCV, who received a liver biopsy at the Liver Center of the University of California, San Diego. A total of 58 of these patients had a positive history of alcohol abuse, and we analyzed them separately in a sensitivity analysis. AST/ALT ratio and platelet counts were determined in all patients. Fibrosis was staged using the METAVIR score. RESULTS: Both AST/ALT ratio and platelet counts correlated significantly with the disease stage (r = 0.190, p = 0.006, and r = -0.543, p < 0.00, respectively). In a sensitivity analysis, there was no correlation between AST/ALT ratio and disease stage for patients with a history of alcohol abuse. For patients without history of alcohol abuse, the correlation between disease stage, AST/ALT ratio, and platelet counts was r = 0.297, p < 0.00, and r = 0.560, p < 0.00, respectively. In these patients, AST/ALT ratio > or =1 in combination with a platelet count of <150,000/mm3 can identify patients with severe fibrosis or cirrhosis (stages 3 and 4) with a positive predictive value of 93.1%. Sensitivity, specificity, and negative predictive value were 41.2%, 99.1%, and 85.0%, respectively. In patients with ALT/AST ratio of <1 or platelet counts of >150,000/mm3, these laboratory parameters cannot predict liver fibrosis stage. CONCLUSION: AST/ALT ratio in combination with platelet counts may obviate a liver biopsy for fibrosis staging in some patients with chronic HCV infection.

Adult↗

PubMed1994

Effect of recombinant human erythropoietin on platelets in patients with anemia of renal failure: correlation of platelet count with erythropoietic activity and iron parameters.

We examined the effect of treatment with rHuEpo on platelet counts in 61 hemodialysis patients and correlated them with changes in erythropoietic activity, iron status and inflammation. Platelets (10(9)/1) increased from 220 +/- 80 to 245 +/- 102 after 14 days and stabilized at that level up to day 90 (p < 0.0001). The increment was similar in complete or partial responders but was not observed in failures. Serum transferrin receptor (sTfR, a measure of total erythropoiesis) and Het rose much more progressively, but relative platelet increments correlated with relative increases in sTfR and Hct. Relative platelet increments correlated inversely with relative changes of SeFe or transferrin saturation, but not with their absolute values, nor with baseline ferritin or its progressive decrease. Although baseline platelet count was 12% higher in patients with inflammation and correlated with serum haptoglobin, relative increases were similar in patients with or without inflammation. In conclusion, rHuEpo produced a clinically minor but consistent elevation of platelet counts. These modifications were not related primarily to modifications in iron stores, functional iron deficiency, or inflammation, but paralleled the expansion of erythropoietic activity. The results suggest that rHuEpo has a small positive effect on platelet production, but it cannot be ruled out that this could be partially mediated through functional iron deficiency.

Anemia↗

PubMed2002

Antithrombin III activity and platelet count are more likely to decrease in twin pregnancies than in singleton pregnancies.

BACKGROUND: It is not known whether antithrombin III activity and platelet count are more likely to decrease in women with twin pregnancies than singleton pregnancies. METHODS: We enrolled 56 consecutive women with twin pregnancies and 692 consecutive women with singleton pregnancies. Antithrombin III activity and platelet count were determined at 26-31 weeks and again at 32-40 weeks of gestation. Thrombin-antithrombin complex, and plasmin-alpha2 plasmin inhibitor complex were measured simultaneously in some women. RESULTS: In twin pregnancies, both antithrombin III activity (111 +/- 8.2%) and platelet count (244 +/- 60 x 109/l) at 28.6 +/- 1.0 weeks decreased over time to 91 +/- 12% and 205 +/- 59 x 109/l, respectively, at 35.2 +/- 1.2 weeks; these decreases were significantly greater than in singleton pregnancies. However, a small number of women with singleton pregnancies had a significant decrease in antithrombin III activity in the absence of preeclampsia. The serum thrombin-antithrombin complex was significantly higher in twin pregnancies than in singleton pregnancies (9.7 +/- 4.2 ng/ml vs. 6.7 +/- 4.4 ng/ml, respectively, p < 0.01), and this increase correlated significantly with the decrease in antithrombin III activity in twin pregnancies (r = -0.459, p < 0.001). CONCLUSIONS: Antithrombin III activity and platelet count show a greater decrease in twin than in singleton pregnancies, perhaps due to a greater increase in thrombin generation.

Adult↗

PubMedDate not supplied

Changes in cardiopulmonary variables and platelet count during anesthesia for total hip replacement in dogs.

Changes in cardiopulmonary function and platelet count were determined in 22 dogs of various breeds that underwent total hip replacement with cemented femoral prostheses. In 11 dogs (group I) polymethylmethacrylate (PMMA) was inserted without venting the reamed and lavaged femoral canal. In a second group of 11 dogs (group II) a urethral catheter (ID: approximately 2.7 mm) was placed into the medullary cavity before the insertion of PMMA. The application of PMMA resulted in a decrease in end-tidal carbon dioxide tension (PETCO2) until 5 minutes after insertion of bone cement. Increases in arterial to end-tidal pCO2 gradient [P(a-ET)CO2] and physiological dead space (VD/VT) were recorded between 2 minutes before and 5 minutes after insertion of PMMA in 12 dogs. A significant decrease in platelet count occurred in both groups of dogs. Decreases in arterial pO2 (PaO2), arterial/alveolar oxygen tension ratio (PaO2/PAO2), and percent O2 saturation of hemoglobin in arterial blood (SaO2) were not statistically significant. No significant differences could be detected between data obtained from both groups of dogs. An increase in femoral intramedullary pressure caused by the insertion of PMMA and subsequent pulmonary microembolism by medullary contents has been considered the most likely cause for changes in pulmonary function. The lack of statistically significant differences in cardiopulmonary variables and platelet count between the two groups of dogs could have been related to inefficient pressure reduction by the method used.

Anesthesia, Intravenous↗

PubMed1982

Beta-thromboglobulin and platelet counts - effect of malignancy, infection, age and obesity.

Plasma levels of beta-thromboglobulin (BTG) and platelet count were studied in 69 control subjects, 19 patients with operable abdominal malignancy, and 9 patients with acute bacterial infection. In control subjects there was a significant rise in BTG and fall in platelet count with age, and a negative correlation of BTG with obesity. BTG and platelet count were normal in patients with operable malignancy, but significantly increased in patients with acute bacterial infection. These effects must be considered in studies of BTG and thrombosis.

Adult↗

PubMed1999

Treatment of the Kasabach-Merritt syndrome with pegylated recombinant human megakaryocyte growth and development factor in mice: elevated platelet counts, prolonged survival, and tumor growth inhibition.

Kasabach-Merritt Syndrome (KMS) is seen in children with large vascular tumors. KMS is characterized by very low platelet counts and a consumption of coagulation factors causing life-threatening complications. It has been proposed that thrombopenia in these patients is caused by intratumoral trapping of platelets. The truncated form of the cMpl-receptor ligand thrombopoietin, pegylated human megakaryocyte growth and development factor (Peg-rHuMGDF), is an agent that stimulates platelet production. We hypothesized that stimulation of the platelet production would prevent the life-threatening complications of patients with KMS owing to low platelet counts. In a mouse model of KMS, with tumors derived from a hemangioendothelioma cell line, we studied the effect of Peg-rHuMGDF. Treatment with Peg-rHuMGDF (10 microg/kg/day intraperitoneally) increased platelet counts by 7-8-fold compared with control tumor-bearing mice after 11 d of treatment (p < 0.001, n = 8). Survival was significantly increased, with 50% of treated animals alive at 1 mo versus 0% in untreated controls. Interestingly, we also observed an inhibition of tumor growth by 75% (p < 0.001, n = 8). Hematoxylin and eosin staining showed fresh fibrin clots in the treated tumors, suggesting that higher platelet counts caused intravascular thrombosis of tumor vessels. We conclude that increased platelet production in this model of KMS resulted in an antivascular tumor effect via platelet trapping. Further, we propose that thrombopoietin may be of critical value in preventing life-threatening complications from KMS.

Animals↗

PubMed1997

Safe epidural analgesia in thirty parturients with platelet counts between 69,000 and 98,000 mm(-3).

Regional anesthesia is a popular form of pain relief for the management of labor and delivery. Thrombocytopenia is considered a relative contraindication to the administration of regional anesthesia. Some authorities have recommended that an epidural anesthetic be withheld if the platelet count is <100,000 mm(-3). For the period of March 1993 through February 1996, we reviewed the charts of all parturients who had a platelet count <100,000 mm(-3) during the peripartum period. Eighty women met this criterion. Of these 80, 30 had an epidural anesthetic placed when the platelet count was <100,000 mm(-3) (range 69,000-98,000 mm(-3)), 22 had an epidural anesthetic placed with a platelet count >100,000 mm(-3) that subsequently decreased below 100,000 mm(-3), and 28 did not receive a regional anesthetic. We found no documentation of any neurologic complications in the medical records. We conclude that regional anesthesia should not necessarily be withheld when the platelet count is <100,000 mm(-3).

Analgesia, Epidural↗

PubMed2003

[Platelet count and hematic punction with epidural block in obstetrics].

INTRODUCTION: The reference value for and the significance of mild thrombocytopenia associated with pregnancy remain undetermined, and therefore the timing, validity and meaning of coagulation tests before a regional block may vary. OBJECTIVE: To determine whether the incidence of bloody puncture is related to preoperative platelet count performed just before an epidural block, to review the incidence of hemorrhagic complications and to determine whether such complications are related to preoperative platelet count. METHODS: We carried a retrospective study of computer records for 1,168 patients given regional blocks to control pain during labor. A blood sample was obtained to assess the platelet count immediately before the block; we then analyzed the correlation between the incidence of bloody puncture and platelet count, with the patients distributed in 4 groups according to the latter. RESULTS: The platelet count of most patients fell between 150,000 and 250,000/mm3. The second largest group had counts between 100,000 and 150,000 platelets/mm3, which would constitute mild thrombocytopenia in non-pregnant patients. Seventy-two bloody punctures were observed, for an incidence of 6.16%, and the incidence was significantly higher in the group of patients with over 350,000 platelets/mm3 (p < 0.05). No severe obstetrical complications, such as obstetric hysterectomy or severe postpartum bleeding occurred. Nor were there cases of epidural hematoma. CONCLUSIONS: A complete clinical history must be obtained during the anesthetist's interview with the patient in the last month of pregnancy, and detailed information on the risk of regional blocks during labor must be offered. When blood tests at the time of the interview are normal and the clinical history indicates low risk, repeating tests immediately before the block is unjustified, provided the clinical situation does not change.

Adult↗

PubMed1995

Synchronous fluctuation of interleukin-6 and platelet count in cyclic thrombocytopenia and thrombocytosis.

We describe a case of cyclic thrombocytopenia and thrombocytosis, whose cytokine levels, granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-6 (IL-6) in plasma, fluctuated in synchrony with platelet count. The levels of the two cytokines correlated significantly with the platelet count for 11 observations over an 8-month period (r = 0.79, p < 0.01 for GM-CSF and r = 0.87, p < 0.001 for IL-6). No inverse relationship between platelet-associated immunoglobulin G (PAIgG) and platelet count was observed (r = 0.39, p > 0.20). These findings suggest that the fluctuation of platelet count in this case may result from an aberration of the cytokine network regulating megakaryopoiesis and platelet formation.

Adult↗

PubMed2003

Influence of platelet count and activity on thromboelastography parameters.

It has been suggested that thromboelastography TEG) can help in limiting or directing the appropriate use of blood products during surgery. However, the contribution of platelets to the TEG profile has not been studied in detail. Blood was taken from eight healthy subjects and eight patients with peripheral arterial disease (PAD). Immunomagnetic separation was achieved by the addition of Dynabeads labeled with a CD41 murine antibody (to the GPIIb/IIIa receptor) to achieve 90-100% depletion of platelets from blood. This was then titrated with whole blood to achieve platelet counts of approximately 0, 25 and 50% of the original count to compare with whole blood using TEG. Platelet function was also assessed by spontaneous platelet aggregometry (SPA) at baseline and at the 50% dilution. SPA, maximum amplitude (MA) and K time were significantly different in PAD patients compared to controls (P < 0.05). In both controls and PAD patients there was a strong linear correlation between Log10 [platelet count] and MA (r = 0.97 for controls, r = 0.89 for PAD) and K time (r = -0.86 for controls, r = -0.68 for PAD). Correlation between Log10 [platelet count] and R time was poor in both groups. The MA and K TEG parameters may be most useful for assessing platelet transfusion requirements.

Aged↗

PubMed1993

Sustained elevation of platelet counts by long-term azidothymidine treatment of immunosuppressed mice.

Azidothymidine (AZT) has been demonstrated to increase platelet counts in patients suffering from acquired immunodeficiency syndrome (AIDS). However, the ability of long-term AZT treatment to sustain increases in platelet counts is controversial. We have recently demonstrated that AZT elevates the levels of circulating platelets in both normal C57BL/6 mice and mice made immunodeficient by infection with LP-BM5 murine leukemia virus (MAIDS mice). We therefore studied the effect of long-term AZT administration on platelet formation in both normal and MAIDS mice. Peripheral blood indices, levels of femoral and splenic megakaryocyte colony forming units (CFU-MK), and plasma levels of cytokines important in platelet formation-interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF)--were examined. Platelet counts remained elevated throughout a 120-day AZT treatment period. Splenic CFU-MK were not significantly changed in MAIDS mice, except at day 15 when they were elevated. Splenic CFU-MK were significantly decreased in normal mice at days 8 and 120, and increased at day 30. Bone marrow CFU-MK were increased by AZT treatment at all time points tested in both normal and MAIDS mice. Plasma levels of GM-CSF were unchanged by AZT treatment in both normal and MAIDS mice. Plasma levels of IL-6 were unchanged in AZT-treated normal mice but decreased in AZT-treated MAIDS mice. These results indicate that long-term AZT treatment maintains elevated levels of platelets in both normal and MAIDS mice and affects CFU-MK colony formation. Our studies add to a growing body of work suggesting that AZT can ameliorate thrombocytopenia associated with HIV disease.

Animals↗