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PubMed1995

Reference materials and reference measurement systems in laboratory medicine. Prothrombin time standardization: the problem of the control plasma.

The prothrombin time of fresh normal pooled plasma and the mean normal prothrombin time are currently recommended as the denominator term in the expression of prothrombin time ratios and International Normalised Ratio (INR) values. Fresh normal pooled plasma is also required for correct extrapolation of percent prothrombin time activity values. To avoid collection and measurement of a relevant number of normal individual samples for calculation of the mean normal prothrombin time or the necessity for a fresh plasma pool, lyophilised normal control plasma is made available by the manufacturers of thromboplastin reagents. The Verband der Diagnostica- und Diagnostikgerätehersteller (VDGH) has adopted a lyophilised normal pooled plasma (R82A) which was calibrated in two studies against fresh normal plasma pools and fresh individual normal plasmas, using a variety of plain and combined thromboplastins. Both studies concluded that plasma R82A could be used as a substitute for normal plasma, but a correction should be made for plain thromboplastin reagents. These data have been confirmed in an IFCC collaborative international study organised by the IFCC Working Group Standardisation of Coagulation Tests. In the latter study, in addition to plain and combined thromboplastin reagents, the recently introduced recombinant thromboplastins were evaluated and they showed a significant deviation from the sensitivity observed with extracted thromboplastins. Recombinant thromboplastins are under consideration as future international reference thromboplastins; the results of the IFCC collaborative study call for additional experimentation before this is accomplished.

Blood↗

PubMed1994

Resistance to activated protein C: evaluation of three functional assays.

Resistance to Activated Protein C (APC) was evaluated using 3 different methods: two of them were based on the prolongation of the Activated Partial Thromboplastin Time (APTT) using 2 different APTT reagents in the presence of APC, whereas the third method was based on the prolongation of prothrombin time when APC is added. The three methods were significantly correlated. APTT-based assays were sensitive to factor XII deficiency, whereas thromboplastin-based assay was sensitive to factor VII deficiency (< 0.5 UI/ml), which surestimates the response to APC. In contrast, an increase in factor VIII (F. VIII) level is associated with a decreased response to APC, when APTT-based assays are used, whereas thromboplastin-based assay is unmodified. During pregnancy, a decreased response to APC is observed, which is not only due to the increase in F. VIII, since thromboplastin-based assay is also modified. In Protein S (PS) immuno-depleted plasma, the low response to APC is corrected by addition of free PS: the thromboplastin-based assay was the most sensitive one to PS deficiency. However, in patients with congenital PS deficiency, there was no correlation between APC-resistance and free PS level. In patients with lupus anticoagulant, discrepancies were observed between the 3 methods, but with a high frequency of low response to APC. For the 3 assays, there was a good differentiation and correlation between normal and pathological results, the thromboplastin-based assay being perhaps the most discriminating. However, 3 unrelated thrombophilic patients showed normal results using thromboplastin-based assay, although they were APC-resistant using APTT-based assays. For 2 patients, this discrepancy can be explained by high levels of F. VIII. For the last patient, an abnormal F. VIII, resistant to APC can be suspected.

Adult↗

PubMed1996

Calibration verification of the International Normalized Ratio.

The International Normalized Ratio (INR) system for reporting the prothrombin time (PT) is essentially a calibration activity intended to standardize PT reporting across various reagent/instrument systems. However, complete standardization of PT reporting through the INR has been difficult to achieve for a variety of reasons, including inaccurate assignment of thromboplastin International Sensitivity Indexes (ISIs) and specific (local) reagent/instrument effects. Until now, the individual laboratory has not been able to easily verify the accuracy of its INR. Using standard lyophilized plasmas with INR values assigned against IRP RBT/90 rabbit thromboplastin, the authors present a method that allows a laboratory to locally verify its range of accuracy for the INR. The method is illustrated on a single coagulometer with two thromboplastin lots of differing sensitivity (Pacific Hemostasis Thromboplastin-DS and Thromboplastin-D from rabbit sources, with respective International Sensitivity Indexes of 1.20 and 1.97). In this illustration of the method, the accuracy of Thromboplastin-DS was superior to that of Thromboplastin-D. Interpretation of the data and cautions regarding the use of standard plasmas for calibration verification are discussed. Using this method, a reportable range of accuracy at a given error tolerance can be established locally for INR measurements within a laboratory. Laboratories of any size can apply this method to study the accuracy of their INR reagent/instrument systems, thus performing calibration verification. When used in conjunction with assessments of assay precision, this method can help laboratories to select better reagent/instrument systems and thereby produce more accurate and more clinically meaningful INR results.

Animals↗

PubMed2002

[Introduction of international normalized ratio of prothrombin time to evaluate multiple depletions of coagulation factors].

Prothrombin time(PT) is utilized in worldwide as a global coagulation test reflected multiple depletions of coagulation factors in diseases such as severe liver dysfunction and Disseminated Intravascular Coagulation(DIC). However, standardization of regents and result reporting methods are not established yet except International Normalized Ration(INR) for control of oral anticoagulant therapy(OAT). We evaluated whether INR is capable for defect of multiple coagulation factors except OAT, using absorbed plasma and different origins of thromboplastin; human recombinant, human placenta, cultured human cell and rabbit brain. PTs of individual 90 samples(group MC) absorbed with BaSO4 and/or bentnite and 60 samples(group W) from patients with OAT were measured with 20 normal plasmas with respective reagents. Sensitivities of four reagents to plasma of group W and MC were determined respectively against human recombinant thromboplastin(ISI = 1.03). Both of human thromboplastin showed that sensitivity to absorbed plasma was very close to OAT plasma, whereas reductions of sensitivity to 84% and 66% for absorbed plasma were revealed in both of rabbit thromboplastins. Correlations of INRs calculated by two different sensitivities, one is to absorbed plasma and another to OAT plasma, indicated that discrepancy of sensitivities was emphasized as large slopes(1.50 and 2.76) of regression lines and large intercepts in rabbit thromboplastins, although slopes closed to 1.0 with small intercepts in both of human thromboplastins. We concluded that use of human thromboplastin was the first priority to introduce INR system for evaluation of multiple coagulation factors depletions.

Adult↗

PubMedDate not supplied

[Control of anticoagulant therapy with coumarin derivatives. Evolution of the tests used and their standardization].

Levels of hypocoagulabity induced with coumarin derivatives (aconocoumarin) were determined in 10 patients Quick's test was used to calibrate commercially available thromboplastin reagents against a reference reagent. The results were then standardised in the form of a correct prothrombin ratio. It was found that comparable results could be obtained, even with poorly sensitive thromboplastins, by determining a thromboplastin sensitivity index and using it to convert the prothrombin ratio obtained with each thromboplastin into a "correct" ratio, i.e. one that allowed for the depressed sensitivity of the thromboplastin concerned. It was found that thrombotest was more sensitive than the commercial thromboplastins; it was also superior to the reference reagent in expressing the level of drug-induced hypocoagulability. Attention is drawn to the soundness of expressing prothrombin times in terms of the correct ratio to cut out the effect of variations in sensitivity on the part of commercial thromboplastins. At the same time, stress is laid on the superiority of thrombotest in the monitoring of oral anticoagulant therapy.

Acenocoumarol↗

PubMed1981

New evidence for intrinsic blood coagulation in chickens.

Coagulation of blood in chickens is considered the result of an extrinsic clotting system initiated, as in mammals, by tissue thromboplastin released from injured tissues. Blood coagulation in mammals depends principally on an intrinsic mechanism in which thromboplastin is generated from blood itself. Only a negligible role, if any, has been ascribed to an intrinsic system in chickens. A reevaluation of intrinsic coagulation in chickens was undertaken in this study. Whole blood of chickens was found to clot over 30% faster when contacted by suitable surface activators such as kaolin or glass than when such contact was omitted. Plasma recalcification times were significantly (P less than .02) shortened by contact activators. Clotting functions were measurable both by partial thromboplastin time and activated partial thromboplastin time, tests that bypass extrinsic factors. Intrinsic thromboplastin could be generated from dilute whole chicken blood although at a slower rate than that reported for human blood. Modification of whole blood thromboplastin generation techniques permitted measurement of activities that seem analogous to human intrinsic factors VIII and IX but not XI or XII. These data provide evidence of a functioning intrinsic clotting mechanism in chickens. A complete description and role for this mechanism remains to be defined.

Animals↗

PubMed1993

Comparison of the behavior of normal factor IX and the factor IX Bm variant Hilo in the prothrombin time test using tissue factors from bovine, human, and rabbit sources.

A subset of hemophilia B patients have a prolonged bovine-brain prothrombin time. These CRM+ patients are classified as having hemophilia Bm. The prolongation of the prothrombin time has been reported only with bovine brain (referred to as ox brain in some literature) as the source of thromboplastin; prothrombin times determined with thromboplastin from rabbit brain or human brain are not reported to be prolonged. Factor IX from a hemophilia Bm patient (factor IX Hilo) was isolated. The activity of factor IX Hilo was compared to that of normal factor IX in prothrombin time assays when the thromboplastin source was of bovine, rabbit, or human origin. Factor IX, either normal or Hilo, prolonged a prothrombin time regardless of the tissue factor source. However, unless thromboplastin was from a bovine source, this prolongation required high concentrations of factor IX. Further, factor IX normal was as effective as factor IX Hilo in prolonging the prothrombin time when rabbit or human thromboplastin was used. With bovine thromboplastin, factor IX Hilo was significantly better than factor IX normal at prolonging the prothrombin time. The amount of prolongation was dependent on the amount of factor IX Hilo added. In addition, the prolongation was dependent on the concentration of factor X present in the sample. The prothrombin time changed as much as 20 seconds when the factor X concentration was varied from 50% to 150% to normal (fixed concentration of factor IX Hilo). These results demonstrate the difficulty of classifying the severity of a hemophilia Bm patient based on the bovine brain prothrombin time unless both the factor IX and factor X concentrations are known.

Animals↗

PubMed1980

Lupus anticoagulant after measles.

A 2 2/12 years old boy developed a "lupus anticoagulant" after measles. Fibrinogen concentration and activity of factors II, V, VII, VIII, IX, X, XI and XII were normal, but partial thromboplastin time and thromboplastin time were prolonged. Thrombin time was within the normal range. Mixing normal plasma with the patient's plasma immediately prolonged the partial thromboplastin time, and incubation of the sample did not increase the inhibition. The immunglobulin fraction prepared from the patient's plasma on DEAE-sephacel also prolonged the partial thromboplastin time in cross mixing experiments. The thrombocyte count and thrombocyte functions were normal. In spite of the pathological partial thromboplastin and thromboplastin times, surgery was performed without excessive bleeding during the operation and without delayed wound healing.

Blood Coagulation Disorders↗

PubMed1995

Pharmacokinetics and pharmacodynamics of subcutaneous heparin during the early third trimester of pregnancy.

OBJECTIVE: Our purpose was to study the pharmacokinetics and pharmacodynamics of heparin administered subcutaneously during the early third trimester of pregnancy. STUDY DESIGN: We gave subcutaneous heparin (143 units/kg) to six pregnant women (mean gestational age 27.1 +/- 1.2 weeks) and to six women who were not pregnant, who served as controls. We serially measured plasma heparin concentrations and activated partial thromboplastin times over 10 hours and compared the time courses of these two measures in the two groups. We calculated the mean peak plasma heparin concentration, time to peak plasma heparin concentration, peak activated partial thromboplastin time, and time to peak activated partial thromboplastin time and compared these variables in the two groups. RESULTS: Plasma heparin concentrations changed significantly over time in both pregnant and nonpregnant subjects. However, the peak plasma heparin concentration in pregnant subjects was significantly lower than in controls (0.11 +/- 0.017 units/ml vs 0.23 +/- 0.036 units/ml) and the time to peak plasma heparin concentration was significantly shorter in the pregnant patients compared with the nonpregnant controls (113 +/- 20 minutes vs 222 +/- 20 minutes). The peak activated partial thromboplastin time (30.3 +/- 1.7 seconds) was significantly lower and time to peak activated partial thromboplastin time (137 +/- 31 minutes) significantly shorter in the pregnant women compared with nonpregnant controls (50 +/- 4.0 seconds; 230 +/- 26 minutes). CONCLUSIONS: Subcutaneous administration of heparin to pregnant patients results in lower plasma heparin concentrations and clinically insignificant prolongation of the activated partial thromboplastin time compared with equivalent doses administered to nonpregnant women. These findings have important implications for the dosing and monitoring of subcutaneous heparin in pregnant women.

Anticoagulants↗

PubMed1993

Prothrombin fragment F1 + 2 concentrations for monitoring anticoagulation therapy with heparin.

We have compared the activated partial thromboplastin time with measurement of prothrombin fragment F1 + 2 concentrations (ELISA assay) during a 24-h period in a group of patients (n = 10) who had undergone elective coronary angioplasty and were anticoagulated post-procedure with heparin 1000 U/h. Four hours after the procedure all the patients were adequately anticoagulated according to activated partial thromboplastin time (median ratio 4.7:1) and the prothrombin fragment F1 + 2 concentration was significantly lower than pre-angioplasty values (0.5 vs 1.4 nmol/l, p = 0.04). At 24 h the median activated partial thromboplastin time ratio was still higher than the pre-procedure value (1.35 vs 0.9, p < 0.01), but the prothrombin fragment F1 + 2 concentration had risen to 2.1 nmol/l, with more variability in individual results within the patient group for the prothrombin fragment F1 + 2 concentration than for activated partial thromboplastin time (interquartile ranges (Q1, Q3) prothrombin fragment F1 + 2, 1.2-2.5; activated partial thromboplastin time, 1.2-1.5). The activated partial thromboplastin time is the standard method of monitoring the anticoagulant effect of heparin but may not fully reflect the functional coagulation status and accurately identify individual patients with less than adequate anticoagulation. Prothrombin fragment F1 + 2 concentrations may provide a more reliable indicator in individual patients of functional coagulation status in certain important situations where anticoagulation is critical such as following complicated coronary angioplasty.

Angioplasty, Balloon, Coronary↗

PubMed1993

Biologic effects of recombinant hirudin (CGP 39393) in human volunteers. European Hirudin in Thrombosis Group.

OBJECTIVES: The purpose of this study was to investigate the biologic efficacy and pharmacokinetics of different doses of recombinant hirudin administered in single or repeated subcutaneous injections in healthy volunteers. BACKGROUND: Hirudin is a highly specific inhibitor of thrombin, the pivotal enzyme in thrombosis. Differences between hirudin and heparin in experimental animals indicate that hirudin may be a superior antithrombotic drug in humans. METHODS: The biologic effect of recombinant desulfato-hirudin (CGP 39393) administered as single or repeated (every 8 h for 3 days or every 12 h for 6 days) subcutaneous injections was studied in 231 healthy human volunteers. RESULTS: Single subcutaneous doses of 0.1, 0.2, 0.3, 0.4, 0.5 and 0.75 mg/kg body weight in 195, 8, 12, 8, 4 and 4 volunteers, respectively, prolonged the activated partial thromboplastin time in a dose-proportional fashion within the 1st 30 min, with a near-maximal effect for 3 to 4 h after the dose. The mean activated partial thromboplastin time increased to 1.48 and 1.93 times baseline values 30 min after single subcutaneous injections of 0.2 and 0.4 mg/kg of CGP 39393, respectively. There was a linear relation over a wide range between the activated partial thromboplastin time prolongation and plasma concentrations of CGP 39393. Plasma clearance was between 1.5 and 1.7 ml/min per kg. The subcutaneous administration of 0.3 and 0.5 mg recombinant hirudin three times a day for 3 days or two times a day for 6 days prolonged the activated partial thromboplastin time by 1.71 to 1.69 and 1.78 to 1.92 times baseline levels, respectively, with the preinjection values maintained in the hypocoagulable range. No prolongation of bleeding time was measured at peak plasma hirudin levels. Because thrombin and prothrombin times are not able to reflect high or low CGP 39393 concentrations, respectively, neither test is suitable for monitoring administration of this drug. CONCLUSIONS: CGP 39393 appears to be well tolerated in volunteers, even after repeated doses. The activated partial thromboplastin time test seems to be well suited to monitor the anticoagulant effect of recombinant hirudin because the dose effect is linear up to 0.5 mg/kg of subcutaneous CGP 39393. The prolongation of activated partial thromboplastin time after subcutaneous injection of CGP 39393 shows a plateau lasting for 3 h. Further studies are now required to determine the dose that will provide the best antithrombotic effect and the lowest bleeding tendency in arterial or venous thrombosis indications.

Biological Availability↗

PubMed1998

A cross-Canada survey of prothrombin time testing: Does the establishment of local ISI values improve the accuracy of international normalized ratio reporting? Thrombosis Interest Group of Canada.

The international normalized ratio (INR) was established as a means of standardizing the prothrombin time regardless of the thromboplastin used in the individual laboratories. The INR is the prothrombin time ratio of the sample raised to the power of the International Sensitivity Index (ISI). Traditionally, the ISI is determined by using a manual clotting technique by comparing the test thromboplastin with a World Health Organization international reference thromboplastin with results from 60 patient samples standardized on warfarin, and 20 samples from normal volunteers. Most laboratories no longer perform prothrombin time testing by a manual technique but instead automate the procedure by using a variety of coagulation instruments. Thromboplastin ISI values have the potential to be modified considerably by instrumentation, and as a consequence, they, may result in INRs that are unreliable when compared to those obtained by the traditional manual method. It has been proposed that the use of calibrant plasmas tested with the laboratory's thromboplastin and instrument may overcome this problem and a local ISI value could be established. Our study objective was to determine whether a local ISI calibration with the plasma calibrants could reduce the variation of the INR over a wide range of thromboplastin/ instrument combinations. A total of 58 laboratories from across Canada, including community hospitals, private laboratories, and large tertiary care units, participated. The findings indicate that the use of calibrant plasmas to calculate the local ISI does improve the accuracy of INR reporting in the majority of thromboplastin/instrument combinations.

Autoanalysis↗

PubMed1973

Stability of freeze-dried plasma prepared from patients on oral anticoagulants.

The suitability of freeze-dried plasmas from patients on oral anticoagulants to serve as reference material in the calibration of thromboplastins used in the control of oral anticoagulant treatment was assessed in two centres. One pooled normal plasma and four pooled plasmas from patients at different levels of anticoagulation were collected into HEPES-citrate containing Trasylol. The plasmas, in 1 ml volumes, were freeze dried in siliconized ampoules under the optimal conditions used for biological standards. Small aliquots of the same plasmas were stored at -70 degrees C. Five different thromboplastins were used to carry out the tests on these plasmas. There was little difference in the clotting times obtained with five reference thromboplastins (two human, two rabbit, and one bovine reagent) on frozen and freeze-dried plasma, if the latter was tested immediately after complete reconstitution or within six hours of reconstitution if kept at +4 degrees C. Reconstituted plasmas showed a marked shortening of clotting times when stored at 22 and 37 degrees C if thromboplastins sensitive to activation of factor VII were used. In contrast, when thromboplastins sensitive to factor V were used, prothrombin times in plasmas stored at 22 and 37 degrees C became prolonged due to the loss of factor V.Freeze-dried plasmas from patients on oral anticoagulants can be used to calibrate thromboplastins, provided they are used immediately after complete reconstitution or kept at +4 degrees C for use within four to six hours of reconstitution.

Animals↗

PubMed1989

Importance of factor-IX-dependent prothrombinase formation--the Josso pathway--in clotting plasma.

We report a study on the importance of factor IX activation in thromboplastin-dependent coagulation in plasma. Diluted, CaCl2-containing thromboplastin solutions at constant phospholipid concentration were used to trigger the coagulation in plasma from patients with congenital factor IX and factor VIII deficiency in the presence and absence of added factors IX and VIII, and the generation of thrombin activity was monitored. When coagulation is triggered with the high thromboplastin concentrations normally used in clinical routine tests, the generation of thrombin activity in plasma of patients with congenital factor IX deficiency before and after reconstitution with purified factor IX appears identical. When, however, coagulation is triggered with low thromboplastin concentrations, a clear dependency of the generation of thrombin activity on the concentration of factor IX becomes evident at factor IX concentrations lower than 30 nM (about 40% clotting factor activity). Factor VIII is a compulsory cofactor for this factor IX activity because the prothrombinase activity at optimal factor IX concentration is still critically dependent upon the amount of factor VIII present. The lower the amount of thromboplastin, the higher the importance of factor IX and factor VIII activation in thromboplastin-dependent coagulation. This suggests a role of this pathway in pathophysiological thrombin formation.

Blood Coagulation↗

PubMed1979

The optimal therapeutic range in oral anticoagulation. History and proposal.

For patients on oral anticoagulation controlled with Quick's prothrombin time test using rabbit brain thromboplastin American clinicians proposed in the early 1940s that the lower limit of prolongation be taken at 1.5 and the upper limit at 3, corresponding to 10-30% prothrombin activity on a saline dilution curve. Thromboplastins derived from other tissues and species were later introduced, methods were modified, and adsorbed plasma was used instead of saline in the construction of the dilution curve to obtain percentage prothrombin activity; ratios and percentages lost their initial significance, but too often without the clinicians' awareness. With the detection of PIVKAs, finally, it became clear that transformation of prothrombin times into percentage activity, as obtained from dilution curves, could never be a valid means of standardization. It also became evident that only direct comparison of thromboplastins with (fresh) plasma from patients on stabilized oral anticoagulants could be used to determine equivalent therapeutic ranges for different types of thromboplastins. Reference thromboplastins were established and calibration procedures developed. A series of well-controlled clinical trials has provided sufficient information to define, in terms of these reference thromboplastins, therapeutic ranges for the prophylaxis and treatment of venous as well as arterial thrombosis. Definition of the ranges in terms of the biochemical defect induced by coumarin congeners remains, however, to be established.

Administration, Oral↗

PubMed1982

An alternative extrinsic pathway of human blood coagulation.

To study the interrelationships of the major human coagulation pathways, factor X activation in normal and various deficient human plasmas was evaluated when clotting was triggered by dilute rabbit or human thromboplastin. Various dilutions of thromboplastin were added to plasma samples containing 3H-labeled factor X, and the time course of factor X activation was determined. At a 1/250 dilution of rabbit brain thromboplastin the rate of factor X activation in factor VIII or factor IX deficient plasma was only 10% of the activation rate seen for normal or factor XI deficient plasma. Reconstitution of the deficient plasmas with factors VIII or IX, respectively, restored normal factor X activation. Similar results were obtained when various dilutions of human thromboplastin replaced the rabbit thromboplastin. From these experiments, it is inferred that normal activation of factor X in plasma due to dilute thromboplastin requires factors VII, IX and VIII. An alternative extrinsic pathway that involves factors VII, IX, and VIII may be a major physiologic extrinsic pathway, and this pathway may help to explain the clinical observations of bleeding diatheses in patients deficient in factors IX or VIII.

Animals↗

PubMed1993

Accuracy of drawing coagulation samples from heparinized arterial lines.

OBJECTIVE: To determine the accuracy of activated partial thromboplastin time and prothrombin time studies when samples are drawn through heparinized arterial lines. METHODS: A total sample of 90 grouped blood samples (from 30 subjects) was used. Patients were all male, with a mean age of 65 and were studied within 24 hours of percutaneous transluminal coronary angioplasty. Each patient had three venous control and arterial line sample sets (a total of 90 blood samples) drawn when routinely ordered for monitoring therapy. For the arterial line sample, a discard volume of the deadspace, deadspace + 2 mL, or deadspace + 4 mL was randomly assigned for each sample. The venous control volumes were the same for all three sample sets. RESULTS: A 2 x 3 repeated measures analysis of variance was used to analyze the results. The independent variables were the source of the sample (venous vs arterial) and the discard volume of arterial blood (deadspace, deadspace + 2 mL, deadspace + 4 mL). The dependent variables were the activated partial thromboplastin time and prothrombin time values. Mean arterial activated partial thromboplastin time values were significantly higher than the corresponding venous values. Mean activated partial thromboplastin time values were not significantly different among the discard volumes of blood drawn. However, there was a significant source by volume interaction. Tukey post-hoc comparisons of venous-arterial activated partial thromboplastin time differences among the three volumes showed significant differences between deadspace volume and deadspace + 2 mL, and deadspace volume and deadspace + 4 mL. There was no significant difference between deadspace + 2 mL and deadspace + 4 mL volumes. CONCLUSION: Results indicated that the minimal amount of discard volume for accurate activated partial thromboplastin time values in this population of percutaneous transluminal coronary angioplasty patients was the catheter deadspace volume plus 2 mL (total 3.6 mL).

Aged↗

PubMed2001

Timing and volume of fluid administration for patients with bleeding following trauma.

BACKGROUND: Treatment of haemorrhagic shock involves maintaining blood pressure and tissue perfusion until bleeding is controlled. Different resuscitation strategies have been used to maintain the blood pressure in trauma patients until bleeding is controlled. However, while maintaining blood pressure may prevent shock, it may worsen bleeding. OBJECTIVES: To assess the effects of early versus delayed, and larger versus smaller volume of fluid administration in trauma patients with bleeding. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, the specialised register of the Injuries Group, MEDLINE, EMBASE, the National Research Register and the Science Citation Index. We checked reference lists of identified articles and contacted authors and experts in the field. SELECTION CRITERIA: Randomised trials of the timing and volume of intravenous fluid administration in trauma patients with bleeding. Trials in which different types of intravenous fluid were compared were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: We did not combine the results quantitatively because the interventions and patient populations were so diverse. Early versus delayed fluid administration: Three trials reported mortality and two coagulation data. In the first trial (n=598) relative risk (RR) for death with early fluid administration was 1.26 (95% confidence interval of 1.00-1.58). The weighted mean differences (WMD) for prothrombin time and partial thromboplastin time were 2.7 (95% CI 0.9-4.5) and 4.3 (95% CI 1.74-6.9) seconds respectively. In the second trial (n=50) RR for death with early blood transfusion was 5.4 (95% CI 0.3-107.1). The WMD for partial thromboplastin time was 7.0 (95% CI 6.0-8.0) seconds. In the third trial (n=1309) RR for death with early fluid administration was 1.06 (95% CI 0.77-1.47). Larger versus smaller volume of fluid administration: Three trials reported mortality and one coagulation data. In the first trial (n=36) RR for death with a larger volume of fluid resuscitation was 0.80 (95% CI 0.28-22.29). Prothrombin time and Partial thromboplastin time were 14.8 and 47.3 seconds in those who received a larger volume of fluid as compared to 13.9 and 35.1 seconds in the comparison group. In the second trial (n=99) RR for death with a high (100 mm Hg) compared to low (70 mm Hg) systolic blood pressure resuscitation target was 1.02 (95% CI 0.27-3.85). In the third trial (n=25) there were no deaths. REVIEWER'S CONCLUSIONS: We found no evidence from randomised controlled trials to support early or larger volume of intravenous fluid administration in uncontrolled haemorrhage. There is continuing uncertainty about the best fluid administration strategy in bleeding trauma patients. Further randomised controlled trials are needed to establish the most effective fluid resuscitation strategy.

Hemorrhage↗