Ingestion of superwarfarin leading to coagulopathy: a case report and review of the literature

Superwarfarins are found in many pesticides, including D-con, Prufe I and II, Ramik, Talon-G, Ratak, and Contrac. Ingestion of can lead to significant morbidity and even mortality. Physicians need to consider this diagnosis in any patient presenting with coagulopathy of unclear etiology. We present a patient with superwarfarin-induced coagulopathy and review previous cases in adults in the literature. The patient is a 60-year-old man who presented to our medical center with painless hematuria. Laboratory studies revealed an elevated prothrombin time (PT) (42.5 seconds), partial thromboplastin time (PTT) (64.6 seconds), and international normalized ratio (INR) of 7. Liver-associated enzymes were normal, and complete blood cell count (CBC) showed no evidence of disseminated intravascular coagulation. Subsequent work-up included the absence of an inhibitor by mixing study and deficiencies of vitamin K-dependent coagulation factors. The patient's warfarin level was negative. A brodifacoum level was positive, confirming superwarfarin-induced coagulopathy. The patient is currently doing well with normal coagulation studies after receiving high doses of vitamin K for several weeks. The cause of his exposure to superwarfarin remains uncertain. Physicians need to be cognizant of this unusual cause of coagulopathy in adults. The appropriate diagnostic work-up and unique features of therapy are discussed.     

Hemostasis system indices in the course of a 105-day hermo chamber isolation experiment

The present paper deals with studying of hemostasis system indices in the course of the experiment with a 105-day isolation in a hermo chamber. The following values were determined: activated partial thromboplastin time, prothrombin time (PT), prothrombin index (PI), international normalized ratio [relationship] (INR), thrombin time, fibrinogen concentration, soluble fibrin-monomer complexes, D-dimer, plasminogen (PG), activity of antithrombin III, protein C, alpha2-antiplasmin. According to the experiment results, isolation is accompanied by PT prolongation (PI decreasing, INR increasing) which conserves up to the 7th day of the aftereffect period, as well as by PG concentration decreasing. Changes are likely to be connected with peculiarities of reduced motion activity conditions, compensatory physical activity influence, protein and lipid metabolism characteristics changing.     

Oral anticoagulant therapy and international normalized ratios in swine

While monitoring coagulation testing in Yucatan miniature swine being given oral anticoagulants, we noticed instances of high international normalized ratios (INR) without clinical complications in our animal model. All pigs (n = 17) weighed approximately 35.2 kg and were dosed daily with 2 to 3 mg of coumadin. Plasma samples were obtained and assayed for prothrombin time (PT), calculated INR, and activated partial thromboplastin time (APTT) at baseline, and after 7 and 14 days of coumadin therapy. Results of initial testing indicated high INR values after anticoagulation and short APTT values at baseline, which led us to consider the activity of vitamin K-dependent coagulation factors in the pig. This information was not available in literature concerning this strain of swine, and was surprising given that pigs are frequently used cardiac research models. Using the same plasma samples, we repeated the PT, INR, and APTT determinations using different reagents and a different analyzer. We also determined activities of coagulation factors II, VII, IX, and X. Large PT and INR differences were seen between the two instrument/reagent combinations, possibly due to the differences in the thromboplastins used and differences in the photo-optic versus manual clot-detection method of the instruments. Vitamin K-dependent factors in all pigs responded to coumadin by decreasing to < 30.0% activity, except for factor IX. The high INR values were not as pronounced when the second instrument/reagent combination was used, and the results seemed more in line with the animals' clinical condition. With this instrument/reagent combination, the pig can be considered a good model for research requiring oral anticoagulant medication.     

Metastatic prostate cancer complicated with chronic disseminated intravascular coagulopathy causing acute renal failure, mimicking thrombotic thrombocytopenic purpura and hemolytic uremic syndrome: pathomechanism, differential diagnosis and therapy related to a case

Disseminated intravascular coagulopathy (DIC) is characterized as activation of the clotting system resulting in fibrin thrombi, gradually diminishing levels of clotting factors with increased risk of bleeding. Basically two types of DIC are distinguished: (1) chronic (compensated) - with alteration of laboratory values and (2) acute (non-compensated) - with severe clinical manifestations: bleeding, shock, acute renal failure (ARF), transient focal neurologic deficit, delirium or coma. Chronic DIC related to metastatic neoplasia is caused by pancreatic, gastric or prostatic carcinoma in most of the cases. Incidence rate of DIC is 13-30% in prostate cancer, among those only 0.4-1.65% of patients had clinical signs and symptoms of DIC. In other words, chronic DIC is developed in one of eight patients with prostate cancer. DIC is considered as a poor prognostic factor in prostatic carcinoma. The similar clinical and laboratory findings of TTP-HUS (thrombotic thrombocytopenic purpura - hemolytic uremic syndrome) and DIC makes it difficult to differentiate between them. A 71 years old male patient with known chronic obstructive pulmonary disease, benign prostatic hyperplasia, significant carotid artery stenosis, gastric ulcer and alcoholic liver disease was admitted to another hospital with melena. Gastroscopy revealed intact gastric mucosa and actually non-bleeding duodenal ulcer covered by clots. Laboratory results showed hyperkalemia, elevated kidney function tests, indirect hyperbilirubinemia, increased liver function tests, leukocytosis, anemia, thrombocytopenia and elevated international normalized ratio (INR). He was treated with saline infusions, four units of red blood cells and one unit of fresh frozen plasma transfusions. Four days later he was transported to our Institution with ARF. Physical examination revealed dyspnoe, petechiae, hemoptoe, oliguria, chest-wall pain and aggressive behavior. Thrombocytopenia, signs of MAHA (fragmentocytes and helmet cells in the peripheral blood), normal INR, elevated lactate dehydrogenase (LDH) and ARF suggested TTP-HUS. Hemodialysis and six plasmaferesis (PF) were carried out. After the fifth PF, skin manifestations of thrombotic microangiopathy occurred on the feet. Clotting analysis revealed elevated D-dimer (>5 μg/mL), normal fibrinogen (3.2 g/L), a slightly raised INR (1.36) and activated partial prothrombin time (APTT) (45.8 sec), normal reticulocyte (57 G/L) and a slightly low platelet count (123 G/L), which proved to be chronic DIC. Therapeutic dose of low-molecular-weight heparin (LMWH) was started. Elevated prostate-specific antigen (PSA) (109.6 ng/mL) suggested prostatic carcinoma. Prostate biopsy revealed adenocarcinoma (Gleason: 4+4 for left lobe and 3+3 for right lobe). Elevated alkaline phosphatase suggested metastases in the bone, which were confirmed by bone scintigraphy. Combined androgen blockade (CAB) was started. After three months follow-up our patient's status is satisfactory. PSA is in the normal range (4.6 ng/mL). Thrombocytopenia of uncertain origin with normal or raised INR, APTT, elevated D-dimer, normal fibrinogen and reticulocyte count prove the diagnosis of chronic DIC. This process warrants searching for metastatic neoplasia. Due to the relatively low serum levels of circulating procoagulant factors (e.g. tissue factor), therapeutic dose of LMWH can be used with good efficiency in chronic DIC with low risk of bleeding. Severe DIC as a complication of metastatic prostate cancer can be treated by androgen deprivation therapy (ADT) or CAB in combination with ketokonazole and concomitant use of supportive treatment. Deme D, Ragán M, Kovács L, Kalmár K, Varga E, Varga T, Rakonczai E. Metastatic prostate cancer complicated with chronic disseminated intravascular coagulopathy causing acute renal failure mimicking thrombotic thrombocytopenic purpura and hemolytic uremic syndrome: pathomechanism, differential diagnosis and therapy related to a case.     

N-acetylgalactosamine incorporation into a peptide containing consecutive threonine residues by UDP-N-acetyl-D-galactosaminide:polypeptide N-acetylgalactosaminyltransferases

A limited number of glycosylation products were generated in a cell-free system from a portion of the MUC2 tandem repeat, PTTTPITTTTK, when microsome fractions of human colon carcinoma LS174T cells were used as the source of UDP-N-acetyl-D-galactosaminide:polypeptide N-acetylgalactosaminyltransferases (pp-GalNAc-T) in our previous work. The structures of all products suggested that there were only two biosynthetic pathways in the GalNAc incorporation into this peptide. In the present report, the putative biosynthetic intermediates, PTTT*PITTTTK (asterisk designates a GalNAc residue), PT*TTPITTTTK, PTT*T*PITT*T*TK, and PT*TTPIT*T*T*TK, of these two hypothetical pathways were used as acceptors to prove that these two pathways do exist. The incubation products of these glycopeptides, microsome fractions of LS174T cells, and UDP-GalNAc were fractionated by reverse-phase HPLC and their structures were determined using MALDI-TOF MS and peptide sequencing. The products from PTTT*PITTTTK were PTTT*PITTT*TK, PTTT*PITT*T*TK, PTT*T*PI-TT*T*TK, PTT*T*PIT*T*T*TK, PT*T*T*PIT*T*T*TK, and PT*T*T*PIT*T*T*T*K. The products from PTT*-T*PITT*T*TK exactly corresponded to the products with five to seven GalNAc residues from PTTT*PITTTTK. The products from PT*TTPITTTTK were PT*TTPITT*TTK, PT*TTPIT*T*TTK, and PT*TTPIT*T*T*TK. PT*TTP-IT*T*T*TK was not converted further under the applied condition. All the products detected and analyzed were the same as those obtained when the unsubstituted peptide and microsome fractions of LS174T cells were incubated. Immunocytochemical analysis indicated that LS174T cells contain at least four pp-GalNAc-Ts (-T1, -T2, -T3, and -T4), suggesting that control of the order and the maximum number of GalNAc incorporation into this peptide is regulated through the coordinated actions of these and possibly other pp-GalNAc-Ts.     

Influence of the herbicide phosphinothricin on growth and nodulation capacity of Rhizobium meliloti

  Rhizobium meliloti proved to be sensitive to low concentrations of the herbicide phosphinothricintripeptide (PTT) and its active ingredient phosphinothricin (PT), which was formerly assumed to be non-toxic for most of the bacteria analysed. Growth was more strongly reduced in sterile synthetic media and less reduced in sterile soil; in unsterile soil only a transient growth reduction was detectable. Sensitivity was also observed in five out of eight other species analysed. In all sensitive species tested, spontaneous resistances to PT occurred. Under sterile conditions, PTT and PT reduced rhizobial nodulation rates of PT-resistant alfalfa plants drastically; however, nitrogen fixation in the few nodules that arose was unaffected. Because of the small number of nodules, the overall fixation rate was strongly diminished. In unsterile soil, nodulation and nitrogen fixation rates were not changed, possibly because of the rapid degradation of PTT and PT in the soil. Using a herbicide as model substance it could be demonstrated that the sensitivity of R. meliloti to chemical additives in the soil can be detected by analysing its growth rate, and that even a weak impact can influence its nodulation capacity. R. meliloti has proven to be a fast, easy and sensitive detection system for bacteriostatic components present in the soil. Received: 12 April 1996 / Received revision: 15 July 1996 / Accepted: 18 July 1996     

Thromboplastin standards

The Prothrombin Time (PT) test is used for monitoring of treatment with Vitamin K-antagonists (VKA). The result of the PT test should be expressed as the International Normalized Ratio (INR). Calculation of INR is based on the availability of International Standards (IS) for thromboplastin and a calibration model. Calibration of a new PT test system is performed with the appropriate IS and fresh plasma samples of healthy (normal) volunteers and patients treated with VKA. The calibration model is based on the assumption of a linear relationship between the log(PT)'s obtained with the new PT system and the reference IS for both normal and patients' samples. Patients' samples for calibration should be selected by rejecting samples beyond the 1.5–4.5 INR range. Outliers should be rejected defined as points with a perpendicular distance greater than three residual standard deviations from the line of relationship. Selection of patients' samples and rejection of outliers result in a reduction of the between-laboratory variation of calibration. In addition to monitoring of VKA, the PT is used for management of patients with chronic liver disease. Likewise, INR_liver should be based on calibration with an IS using samples from patients with chronic liver disease.     

Inducing Acute Traumatic Coagulopathy In Vitro: The Effects of Activated Protein C on Healthy Human Whole Blood

Introduction

Acute traumatic coagulopathy has been associated with shock and tissue injury, and may be mediated via activation of the protein C pathway. Patients with acute traumatic coagulopathy have prolonged PT and PTT, and decreased activity of factors V and VIII; they are also hypocoagulable by thromboelastometry (ROTEM) and other viscoelastic assays. To test the etiology of this phenomenon, we hypothesized that such coagulopathy could be induced in vitro in healthy human blood with the addition of activated protein C (aPC).

Methods

Whole blood was collected from 20 healthy human subjects, and was “spiked” with increasing concentrations of purified human aPC (control, 75, 300, 2000 ng/mL). PT/PTT, factor activity assays, and ROTEM were performed on each sample. Mixed effect regression modeling was performed to assess the association of aPC concentration with PT/PTT, factor activity, and ROTEM parameters.

Results

In all subjects, increasing concentrations of aPC produced ROTEM tracings consistent with traumatic coagulopathy. ROTEM EXTEM parameters differed significantly by aPC concentration, with stepwise prolongation of clotting time (CT) and clot formation time (CFT), decreased alpha angle (α), impaired early clot formation (a10 and a20), and reduced maximum clot firmness (MCF). PT and PTT were significantly prolonged at higher aPC concentrations, with corresponding significant decreases in factor V and VIII activity.

Conclusion

A phenotype of acute traumatic coagulopathy can be induced in healthy blood by the in vitro addition of aPC alone, as evidenced by viscoelastic measures and confirmed by conventional coagulation assays and factor activity. This may lend further mechanistic insight to the etiology of coagulation abnormalities in trauma, supporting the central role of the protein C pathway. Our findings also represent a model for future investigations in the diagnosis and treatment of acute traumatic coagulopathy.     

烙铁头蛇毒对体外血凝及纤溶的影响

行体外血凝及纤溶观察结果表明：①烙铁头蛇毒能明显延长凝血活酶时间（ＰＴＴ）、凝血酶原时间（ＰＴ）及蝰蛇毒磷脂时间（ＲＶＶＣＴ）,显示出较强的抗凝活性;②对人纤维蛋白原及纤维蛋白有较强的溶解作用,这种作用不完全是单一的活化素样作用,还有脆浆素样作用     

Hemostasis system indices in the course of a 105-day hermetic chamber isolation experiment

Changes in hemostasis indices in the course of a 105-day hermetic chamber isolation experiment were studied. The following indices were measured: the activated partial thromboplastin time (APTT); the prothrombin time (PT); the prothrombin index (PI); the international normalized ratio (INR); the thrombin time (TT); the concentrations of fibrinogen, soluble fibrin-monomer complexes (SFMC), D-dimer, and plasminogen (PG); and the activities of antithrombin III, protein C, and α₂-antiplasmin. Isolation was accompanied by PT prolongation (with PI decreasing and INR increasing) observed until the seventh day of the aftereffect period, as well as a decrease in the PG concentration. The changes are likely to have been related to the specific motor activity mode, the effect of compensatory physical exercise, and changes in the characteristics of protein and lipid metabolisms.     

不同全自动凝血仪检测结果的分析研究

目的:探讨不同全自动凝血分析仪检测结果是否具有可比性,同时对其检测结果临床可接受性进行评估,使不同全自动凝血分析仪检测结果标准化.方法:连续30天用SYSMEX CA- 1500及CA-7000全自动凝血分析仪同时检测并比对仪器配套定值质控物的PT、INR、APTT、FIB、TT值;同时连续30天利用两台仪器检测并对比新鲜血标本的PT、INR、APTT、FIB、TT值.结果:SYSMEX CA- 1500及CA-7000日间质控物各检测项目:PT、INR、APTT、FIB、TT变异系数均小于5％.CA- 1500及CA-7000全自动凝血分析仪检测新鲜血标本:PT、INR、APTT、FIB、TT统计分析结果,t检验其P值均＞0.05;相关系数r在0.993-0.999之间;两台仪器的偏差均符合1/2美国CLIA’88能力验证分析质量要求.结论:两台仪器PT、INR、APTT、FIB、TT的检测结果具有很好的相关性,经统计分析两台仪器检测结果无统计学意义.对不同凝血分析仪进行比对分析,不仅能够及时发现仪器存在的系统误差.而且使其检测结果具有很好的一致性,给临床可提供一个准确、可靠一致的实验室检测结果,使临床对疾病的诊断、疗效观察有一个统一的评判标准.     

High dose supplementation of RRR-alpha-tocopherol decreases cellular hemostasis but accelerates plasmatic coagulation in type 2 diabetes mellitus.

BACKGROUND: Diabetes mellitus is associated with increased generation of free oxygen radicals and depleted scavenging potential (oxidative stress), leading to increased LDL oxidation and platelet hyperreactivity, the major components of atherothrombotic vascular lesions. A main goal of antioxidant therapy is to protect the LDL particle from atherogenic oxidation and to reduce the activated cellular hemostasis. METHODS: We evaluated the influence of a high dose supplementation with 800 IU of the natural antioxidant RRR-alpha-tocopherol (vitamin E) per day for six months on serum levels, vitamin E load of LDL particles (HPLC), lag phase of LDL oxidation (Esterbauer's assay), platelet adhesion molecules, leukocyte-platelet coaggregation (flow cytometry, D-III protocol) and coagulation (INR/PTT) in a group of 36 patients with type 2 diabetes (f/m 22/14; age 58+/-8.0; HbA1 at baseline 10.25+/-1.7). RESULTS: Average vitamin E levels increased 2.65-fold accompanied by a 1.83-fold increase of LDL-associated vitamin E and a 12.3 min prolongation of the lag-phase of LDL oxidation (p<0.001 for all parameters at six months). Platelet expression of PECAM-1 (CD31) (-30.2% positive cells, p<0.001; antigen density -25%, p<0.001), ICAM-2 (CD102) (-2.9% positive cells, p<0.01; antigen density -10.6%, p<0.001) and fibrinogen (-1.6% positive cells, p<0.001; antigen density - 16.1 %, p<0.001) decreased. Concomitantly, platelet-leukocyte-coaggregation increased by 44% (p<0.001), correlating to an INR reduction of 10.4% (1.06+/-0.09 to 0.95+/-0.09, p<0.001, r = - 0.34). The PTT remained constant. CONCLUSION: The antioxidant protection from the increased vitamin E was accompanied by a decreased expression of constitutive and function-dependent platelet adhesion molecules. However, increases in platelet-leukocyte coaggregates and a shortened INR time suggest extrinsic coagulation activation, possibly by induction of a leukocyte tissue factor dependent mechanism. High dose supplements of alpha-tocopherol may override the available redox balance in well controlled type 2 diabetes. However, intrinsic effects of alpha-tocopherol must be discussed.     

Problems of the laboratory control of oral anticoagulant treatment

The paper deals with the estimation (using the Monte Carlo method) of a confidence interval for an individual patient's International Normalized Ratio (INR) of 3.3. The results show that this confidence interval ranges from an INR of 2.5 to 4.2 and is of about the same size as the therapeutic range.     

Salvage of a failing microvascular free muscle flap by direct continuous intravascular infusion of heparin: a case report

A free gracilis muscle transfer with skin graft was performed for reconstruction of a type IIIB lower extremity traumatic wound with acute exposure of the distal tibia fracture site and an extensive soft-tissue wound. The free muscle flap failed from a venous thrombosis that was recognized 12 hours postoperatively, and reexploration revealed extensive venous thrombosis throughout the lower leg. The flap was salvaged by direct catheter administration of heparin into the vena comitans of the gracilis artery, which bathed the newly repaired venous anastomosis with an anticoagulating dose of heparin without systemic elevation of the patient's PTT. Ultimate full flap survival and wound healing ensued.     

Effects of high-molecular-weight cryoprotectants on platelets and the coagulation system

The objective of this study is to examine the effects of the most widely used high-molecular-weight cryoprotectants on the coagulation system. Dextran, hydryoxyethyl starch (HES), polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), and albumin were added at different concentrations in the range between 0.01-1% (w/v) to solvent/detergent-treated plasma. Using a STA/STA Compact coagulation analyzer the following clotting tests were performed: prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Factor V, and Factor VIII percentage of activity. PVP and PEG caused a significant increase in APTT, a decrease in Factor VIII percentage of activity, and a slight decrease in TT, while PT and Factor V percentage of activity remained unchanged. Dextran, HES, and albumin did not effect the clotting tests. The effect of high-molecular-weight cryoprotectants on platelets was assessed by platelet-induced clot retraction (PICR) and aggregation with thrombin and agglutination with ristocetin. Platelet aggregation and agglutination were unaffected by all cryoprotectants tested; however, PICR was significantly reduced in the presence of PVP or PEG. Possible mechanisms by which PVP and PEG interfere with the coagulation system are discussed. We also raise issues concerning the development of one-step blood cryopreservation techniques which do not require cryoprotectant removal prior to transfusion.     

The influence on coagulation of transdermal estrogen hormone replacement therapy as a preoperative preparation of the tissue before vaginal hysterectomy

In 32 postmenopausal patients who underwent vaginal hysterectomy due to the presence of uterine prolapse at the Department of Uro-gynaecology and Pelvic Floor Disorders in the Clinic of Gynaecology and Obstetrics, Medical School, Skopje in the period from 1st January 2002 to 1st January 2003, and who were preoperatively treated with transdermal estradiol 50 microg/day during 14 days the following parameters of the coagulating status were estimated: prothrombin time (PT) that is expressed in: absolute value, percentage and INR; activated partial thromboplastin time (aPTT Pathrombin SL); thrombin time and platelets number before and after hormone replacement therapy. After 14-day transdermal estrogen therapy, the parameters: PT, PT%, PT INR, aPTT Pathrombin SL didn't expressed significant changes, the thrombin time expressed significant extension, and the platelets expressed a significant decrease. According to our results, the transdermal estrogens might not have any influence on the hepatic synthesis of coagulating factors till the step of prothrombin formation. They might have an essential influence on the step of prothrombin transformation into thrombin, as well as on the process of megacaryocytes segregation into platelets.     

Investigation of associations between ABO blood groups and coagulation,fibrinolysis, total lipids,cholesterol, and triglycerides

Summary To investigate possible associations between ABO blood system and coagulability levels, fibrinolysis, total lipids, cholesterol, and triglycerides, the plasma and serum of 300 Rh-positive male blood donors were tested. The tests performed were: RT, PTT, K-PTT, PT, F.V, F.II, F.VIII, Complex II, VII, and X, TGT, fibrinogen, HAE 0.2, HAE 0.5, ELT, LIP, Col. 1, Col. 2 and TRI.Analysis of the laboratory data shows a lower coagulability in O blood group individuals. This result was obtained in coagulation tests (RT, PTT, and K-PTT) specific for factor VIII level. In addition, a higher sensitivity to the in vitro heparin anticoagulant effect in O group individuals was confirmed. Nevertheless, these conclusions are specific for Negroids, the same effects not being observed in Caucasians. None of the other laboratory tests revealed any differences related to either blood group or race.     

超高龄患者填充骨水泥型人工股骨头置换术后的凝血功能变化及意义

目的：观察骨水泥填充对人工股骨头置换术术后超高龄老年患者凝血系统的影响。方法：选择80岁以上骨水泥型人工股骨头置换术患者29例,于术前、术后当天及术后第3天空腹抽取静脉血,测定凝血功能相关指标,包括凝血酶原时间（PT）、部分凝血活酶时间（APTT）、凝血酶时间（TT）、凝血酶原活动度（PTA）、国际标准化比值（INR）、纤维蛋白原（FIB）、D二聚体（DD）、抗凝血酶Ⅲ（ATⅢ）、血小板（PLT）水平,并对结果进行比较分析。结果：患者术后当天FIB、DD、显著升高（P〈0.05）,ATⅢ降低（P〈0.05）,提示高凝状态,且纤溶亢进,此时段TT、PT延长（P〈0.05）,血小板明显降低,提示存在出血风险;术后第3天TT、PT显著延长（P〈0.05）,ATⅢ恢复到术前水平,FIB,DD水平较手术后当天下降,提示术后第3天有明显的出血倾向,凝血与纤溶系统逐渐恢复平衡。结论：骨水泥型人工股骨头置换术对80岁以上超高龄患者凝血功能有显著影响,术后当天高凝状态、纤溶亢进,存在潜在出血风险,术后第3天有明显出血倾向,提示高龄患者术后应适当补充凝血因子且须谨慎使用抗凝药物。     

Pulse transit time reveals drug kinetics on vascular changes affected by propofol

Pulse transit time (PTT) is the duration in which a pulse wave travels between two arterial sites within the same cardiac cycle. The aim of our study is to use PTT to examine propofol's effects on the vascular system. Methods. We collected data from 50 healthy women, between 28 and 51 years old, who underwent gynaecological surgery under general anaesthesia. The general anaesthesia was induced with propofol injection (2 mg/kg). PTT measurements were obtained from the R-wave of electrocardiogram and the pulse wave of photoplethysmograph. Two PTT values were obtained; one before (the control) and the other after propofol injection. The results were analysed by Student's t-test. Results. After propofol injection, the PTT was prolonged. The change in the PTT value from that of baseline was significant statistically (P < 0.05, by Student's t-test). The PTT change over time correlated with the degree of vasodilatation over time. Monitoring of PTT not only revealed the magnitude of vascular changes but also demonstrated the onset of vascular dilation, its peak and duration. We conclude that PTT is a useful guide in monitoring the drug kinetics of propofol.