Efficacy of the bleeding risk scoring system for optimal prophylactic anticoagulation therapy of venous thromboembolism in trauma patients: a single-center, retrospective, observational cohort study.

BACKGROUND: We developed a bleeding risk scoring system (BRSS) using prophylactic anticoagulation therapy to comprehensively assess the risk of venous thromboembolism (VTE) in trauma patients. This study evaluated the usefulness of this system in trauma patients, with a focus on minimizing the rate of bleeding events associated with prophylactic anticoagulation therapy. METHODS: We retrospectively evaluated the efficacy of BRSS in trauma patients who received prophylactic anticoagulation therapy for VTE at the Kitasato University Hospital Emergency and Critical Care Center between April 1, 2015, and August 31, 2020. To compare the incidence of bleeding events, patients were divided into two groups: one group using the BRSS (BRSS group) and another group not using the BRSS (non-BRSS group). RESULTS: A total of 94 patients were enrolled in this study, with 70 and 24 patients assigned to the non-BRSS and BRSS groups, respectively. The major bleeding event rates were not significantly different between the two groups (BRSS group, 4.2%; non-BRSS group, 5.7%; p = 1.000). However, minor bleeding events were significantly reduced in the BRSS group (4.2% vs.27.1%; p = 0.020). Multivariate logistic regression analysis showed that BRSS was not an independent influencing factor of major bleeding events (odds ratio, 0.660; 95% confidence interval: 0.067-6.47; p = 0.721). Multivariate logistic regression analysis showed that BRSS was an independent influencing factor of minor bleeding events (odds ratio, 0.119; 95% confidence interval: 0.015-0.97; p = 0.047). The incidence of VTE did not differ significantly between groups (BRSS group, 4.2%; non-BRSS group, 8.6%; p = 0.674). CONCLUSIONS: BRSS may be a useful tool for reducing the incidence of minor bleeding events during the initial prophylactic anticoagulation therapy in trauma patients. There are several limitations of this study that need to be addressed in future research.

Internal Validation of a Risk Scoring System for Venous Thromboembolism After Total hip or Knee Arthroplasty.

We developed a computerized clinical decision support system (CCDSS) for venous thromboembolism (VTE) risk assessment. We aimed to demonstrate its relevance and evaluate associations between risk level and VTE incidence in patients undergoing total hip/knee arthroplasty. In this case-control study, VTE was confirmed using ultrasonography/computed tomography angiography in 1098 adults at a tertiary care hospital over five years (2013-2018). Postoperative VTE incidence was classified into three risk levels (moderate, high, and highest). The overall VTE incidence was 11.7%, which increased with a risk level of 0%, 5.8%, and 12.8% in moderate-risk, high-risk, and highest-risk patients, respectively. Highest-risk patients were significantly more likely to develop VTE than high-risk patients (odds ratio [OR] 2.4; 95% confidence interval [CI] 1.2-5.5; p = 0.01). VTE development was more likely in patients with risk scores ≥4 relative to those with risk scores of 2-3 (OR 1.8; 95% CI 1.2-2.7; p = 0.003) and -1 to 1 (OR 3.3; 95% CI 1.6-7.7; p < 0.001). This study indicates that risk level and VTE incidence are associated; our scoring system appears useful for patients undergoing total hip/knee arthroplasty.

Detailed Changes in Oxygenation following Awake Prone Positioning for Non-Intubated Patients with COVID-19 and Hypoxemic Respiratory Failure-A Historical Cohort Study.

Few studies have reported on the effectiveness of awake prone therapy in the clinical course of coronavirus disease (COVID-19) patients. This study aimed to investigate the effects of awake prone therapy during spontaneous breathing on the improvement of oxygenation over 3 weeks for COVID-19 acute respiratory failure. Data of consecutive COVID-19 patients with lung disorder with a fraction of inspired oxygen (FIO2) ≥ 0.4 and without tracheal intubation were analyzed. We examined changes in SpO2/FIO2, ROX index ((SpO2/FIO2)/respiratory rate) and the seven-category ordinal scale after the initiation of FIO2 ≥ 0.4 and compared these changes between patients who did and did not receive prone therapy. Of 58 patients, 27 received awake prone therapy, while 31 did not. Trend relationships between time course and change in SpO2/FIO2 and ROX index were observed in both groups, although a significant interaction in the relationship was noted between prone therapy and change in SpO2/FIO2 and ROX index. The seven-category ordinal scale also revealed a trend relationship with time course in the prone therapy group. The awake prone therapy was significantly associated with a lower rate of tracheal intubation. In patients with COVID-19 pneumonia treated with FIO2 ≥ 0.4, awake prone therapy may improve oxygenation within two weeks.

Venoarterial extracorporeal membrane oxygenation for septic cardiomyopathy caused by Pasteurella multocida infection: a case report.

Pasteurella is a gram-negative coccobacillus that is commonly transmitted through cat and dog bites and causes various diseases in humans. In the present case, kissing an animal caused Pasteurella multocida infection, leading to sepsis and cardiogenic shock. We used venoarterial extracorporeal membrane oxygenation (VA-ECMO) to support the cardiovascular system until recovery. A 62-year-old man with no relevant history was referred to our hospital with a 1-day history of sore throat and fever. He was diagnosed with cervical cellulitis and later developed septic shock, which necessitated catecholamine administration and intubation. It was subsequently revealed that the patient had Pasteurella multocida bacteremia and kept a pet dog at home. In addition to sepsis, the patient experienced refractory cardiogenic shock and was unresponsive to medical treatment; therefore, VA-ECMO was initiated. After its introduction, the patient's hemodynamic status improved, and he was weaned from extracorporeal circulation after 6 days. He was discharged home and resumed his former life 50 days later. Pasteurella multocida infection can cause sepsis followed by severe cardiac dysfunction in healthy adults. Therefore, VA-ECMO may be a useful treatment option in patients with sepsis-induced myocardial dysfunction and refractory cardiogenic shock.

Venous thromboembolism risk factors and usefulness of a risk scoring system in lower limb orthopedic surgery: A case-control study in Japan.

ABSTRACT: We previously developed a computerized clinical decision support system based on national consensus guidelines and previous studies. This system was used to assess the risk of venous thromboembolism. In this study, we examined the risk factors for venous thromboembolism in patients who underwent lower limb orthopedic surgery using our risk scoring system, to investigate the association between the total risk score and the occurrence of venous thromboembolism.We retrospectively evaluated the records of 649 patients who underwent lower limb orthopedic surgery at a tertiary care center in Japan between January 2015 and August 2018. Venous thromboembolism was confirmed using ultrasonography or computed tomography angiography. The computerized clinical decision support system was used throughout the hospitalization period. Independent risk factors for postoperative venous thromboembolism were identified using logistic regression analysis.Age (≥68 years) was significantly associated with an increased risk of venous thromboembolism (adjusted odds ratio: 1.06, 95% confidence interval: 1.03-1.09; P < 0.001). Furthermore, the Cochran-Armitage trend test revealed a significant positive correlation between the total risk score and the occurrence of venous thromboembolism (P < 0.001).Our risk scoring system may be used preoperatively to determine the need for venous thromboembolism prophylaxis. This study suggests that age (≥68 years) may be a risk factor for venous thromboembolism after lower limb orthopedic surgery. Additional studies are needed to validate these results.

Assessment of Sarcopenia in the Intensive Care Unit and 1-Year Mortality in Survivors of Critical Illness.

Skeletal muscle wasting in the intensive care unit (ICU) has been associated with mortality, but it is unclear whether sarcopenia, defined by skeletal muscle mass and function, is useful for detailed risk stratification after ICU discharge. In this cohort study, 72 critically ill patients with an ICU stay of ≥48 h were identified. Skeletal muscle mass was assessed from the muscle thickness (MT) of the patients' quadriceps using ultrasound images before ICU discharge. Skeletal muscle function was assessed from the patients' muscle strength (MS) before ICU discharge according to the Medical Research Council sum score. A diagnosis of sarcopenia in the ICU was made in patients with low MT and low MS. The study endpoint was 1-year mortality. Sarcopenia in the ICU was diagnosed in 26/72 patients (36%). After adjusting for covariates in the Cox regression, sarcopenia in the ICU was significantly associated with 1-year mortality (hazard ratio 3.82; 95% confidence interval, 1.40-10.42). Sarcopenia in the ICU, defined by low skeletal muscle mass and function, was associated with 1-year mortality in survivors of critical illness. Skeletal muscle mass and function assessed at the bedside could be used to identify higher-risk patients in the ICU.

Use of electrical muscle stimulation body massager (EMS-BMs) improves deep venous blood flow.

We investigated whether using electrical muscle stimulation body massagers (EMS-BMs) for the passive contraction of the lower extremity muscles reduces venous stasis in the deep veins of the lower extremities. In this randomized crossover design study of 20 healthy volunteers between November 2018 and February 2019, we measured both the popliteal and femoral vein peak velocities (PV, cm/s) and blood flow volumes (BFV,mL/min), using pulsed-wave Doppler ultrasound at rest (baseline), and at 2 and 10 min after starting EMS-BM use. Two EMS types: types A (two small pads) and B (one large pad) devices respectively, were examined. The PVs of the femoral (A: 23±7, B: 25±8) and popliteal (A: 26±12, B: 27±12) veins and BFV of types A (107±46) and B (141±88) of the femoral vein were significantly increased compared to the baseline (PV of femoral vein: 19±9, PV of popliteal vein: 14±5, BFV of popliteal vein: 81±46) (P<0.01). No significant differences occurred between the devices in the PV or BFV at either 2 or 10 min. Regardless of the type of stimulation or the shape of the pad, contraction of the lower limb muscles by EMS-BM effectively reduces venous stasis in the lower limb.

Preoperative sepsis is a predictive factor for 30-day mortality after major lower limb amputation among patients with arteriosclerosis obliterans and diabetes.

BACKGROUND: While many patients with lower limb ischemia also have severe infections, few studies have investigated whether the presence of preoperative sepsis affects patient prognosis following lower limb amputation (LLA). Therefore, we investigated the factors (including sepsis as defined in SEPSIS-3) that contribute to the acute mortality rate in patients who underwent LLA due to arteriosclerosis obliterans (ASO) or diabetes mellitus (DM). METHODS: In this retrospective, single-center, 10-year chart review study, 122 adult patients who underwent LLA due to ASO and/or DM were identified from 56,438 surgery cases. Patient characteristics, including co-morbidities, surgical conditions, the presence/absence of sepsis, and acute physiological condition after surgery, were investigated in patients who died within 30 days of LLA and those who survived. Univariate analysis between groups was performed using the chi-square test. Comparisons of age and American Society of Anesthesiologists-Physical Status classification between groups were performed using the Mann-Whitney U test. Risk factors for 30-day mortality after LLA were examined using stepwise logistic regression (backward elimination). Statistical results were considered significant at P < 0.05. RESULTS: Eight cases of mortality (6.6%) were found; we identified the causes as sepsis, myocardial infarction, fatal arrhythmia, and mesenteric artery occlusive disease in 5 (62.5%), 1 (12.5%), 1 (12.5%), and 1 (12.5%) cases, respectively. Using univariate analysis, we identified that age (≥74), delirium, sepsis, intensive care unit admission, non-DM (ASO only), hemodialysis, and acute kidney injury were significantly higher in the mortality group. In logistic regression analysis, non-DM (odds ratio [OR]: 35.2, 95% confidence interval [CI]: 2.8-432) and sepsis (OR: 80.7, 95% CI: 6.7-959) were potential risk factors for 30-day mortality. CONCLUSIONS: This study suggests that cases resulting in amputation due to ASO pathology alone might have poor prognosis and that preoperative sepsis can increase perioperative mortality; hence, the decision to amputate must be considered before the development of sepsis.

[Effect of Preoperative Oral Rehydration on the Hypotension during Spinal Anesthesia.]

BACKGROUND: Preoperative dehydration is one of risk factors of hypotension during spinal anesthesia (SA). We hypothesized that preoperative oral rehy- dration (POR) may help prevent hypotension during SA. METHODS: After obtaining approval from the ethics committee, patients who underwent surgery twice (urological surgery or orthopedic surgery) within 6 months were enrolled in the study. For the first sur- gery, the patients fasted after midnight and were given an intravenous infusion (100 ml - hr-1) on the morning before the surgery (fasting group). During the second surgery, the patients underwent POR (1,200 ml) from the night prior to the surgery to 2 hr before the surgery (POR group). The same amount of anes- thetic drug was administered during both surgeries. The delta systolic blood pressure (ASBP) was mea- sured between the pre-anesthetic condition and the early phase (0-5 min after SA induction) or secondary phase (10-15 min after SA induction). A P value<0.05 in the t-test was considered to indicate statistical sig- nificance. RESULTS: The ASBP was lower in the POR group compared to the fasting group during both the early and secondary phases; however, only the ASBP during the early phase was significantly different (P=0.019). There was no difference in the total amount of fluid infusion, heart rate, and levels of anesthesia between both groups during the study. CONCLUSIONS: POR prevented hypotension immedi- ately after SA induction.

Reduction in the soles of graduated compression stockings prevents falls without reducing the preventive effect for venous stasis.

INTRODUCTION: Graduated compression stockings (GCS) are widely used to prevent venous thromboembolism; however, GCS are slippery and a fall hazard owing to the synthetic fibers. Therefore, we investigated whether changing the sole's shape decreased slipping. MATERIALS AND METHODS: We designed four GCS types with varying sole shapes and normal slipperiness to compare with normal GCS and a barefoot model without GCS (control). A mannequin foot with a GCS type or the control was placed on a ramp at 0°, and the angle was slowly increased. When the mannequin foot had moved ≥100% from the original position, the angle of slide-out (AS) was measured, and the forward and backward AS values were compared. Next, we investigated whether sole modification influenced the effectiveness of the normal GCS for preventing venous stasis. The same GCS type (Torenka) was given to 30 healthy volunteers. Peak systolic velocities (PSV) of the popliteal vein prior to wearing GCS and 20 and 40min after wearing GCS were measured using Doppler ultrasound, and the changes were compared with those of the normal GCS. RESULTS: Only the AS of the GCS type with the smallest sole area (Torenka) was not significantly different from the control's AS, which was significantly larger than the normal GCS' AS. Normal and Torenka GCS resulted in significantly increased PSV after 20 and 40min compared with no GCS, with no significant difference between the two groups. CONCLUSION: Torenka-type GCS were the least slippery but were as effective as normal GCS for venous stasis.

Elective use of surgical cricothyroidotomy for maxillofacial fracture fixation with contraindication of nasotracheal intubation: a case report.

We report three cases of airway management with elective surgical cricothyroidotomy (SCT) for anesthetic management during surgical repair of maxillofacial injury involving basal skull fracture or nasal-bone fracture. In all patients, general anesthesia was induced, a supraglottic airway (SGA) device inserted, and SCT performed. Tracheal intubation was performed through SCT site, and the SGA device was removed. After surgery of maxillofacial fixation, the SGA device was re-inserted and the tracheal tube was removed. No major complications, such as subglottic stenosis or voice change, occurred. SCT holds potential as an alternative to tracheostomy because of ease of performance, fewer complications, and better cosmetic outcomes.

Changes in the incidence, case fatality rate, and characteristics of symptomatic perioperative pulmonary thromboembolism in Japan: Results of the 2002-2011 Japanese Society of Anesthesiologists Perioperative Pulmonary Thromboembolism (JSA-PTE) Study.

PURPOSE: This study aimed to examine the incidence, case fatality rate, and characteristics of perioperative symptomatic pulmonary thromboembolism (PS-PTE) throughout Japan. METHODS: From 2002 to 2011, confidential questionnaires were mailed annually to all Japanese Society of Anesthesiologists-certified training hospitals for data collection to determine the incidence and case fatality rate of PS-PTE patients. Data from 10,537 institutions in which a total of 11,786,489 surgeries had been performed were analyzed using the Mann-Whitney and Chi-square tests. RESULTS: In total, 3,667 PS-PTE cases were identified. The average incidence of PS-PTE was 3.1 (2.2-4.8) per 10,000 surgeries, and the average case fatality rate was 17.9% (12.9-28.8%). The incidence of PS-PTE began to significantly decrease in 2004 compared with that of 2002 (0.0036 vs. 0.0044%: p < 0.01). The case fatality rate temporarily increased toward 2005 (17.9 to 28.8%); however, it gradually decreased since 2008 (15.7%) and was the lowest (12.9%) in 2011. Regarding the trends in prophylaxis, the rate of mechanical prophylaxis increased significantly in 2003 compared with that of 2002 (59.5 vs. 35.0%: p < 0.01), and almost plateaued (73.1-83.1%) after 2004. Furthermore, the rate of pharmacological prophylaxis started increasing in 2008 (17.6%) and reached around 30% after 2009 (28.8-30.2%). CONCLUSIONS: The results of our 10-year survey study show that the incidence of PS-PTE decreased significantly since 2004, and the case fatality rate seemed to show a downward trend since 2008. Major changes in the distribution of prophylaxis in PS-PTE patients were observed.

[Case report of re-expansion pulmonary edema in a patient with anorexia nervosa after removal of a huge ovarian tumor].

We described a case of 19-year-old female who developed re-expansion pulmonary edema (RPE) after removal of a huge ovarian tumor. Altered lung volume after the surgery was observed by chest X-ray. Preoperatively, the lung was highly compressed by the tumor. Patient was intubated under general anesthesia and was ventilated by pressure controlled mode with only 5 cmH2O of positive end-expiratory pressure (PEEP). P/F ratio was changed from 163 to 444 after removal of the tumor. At the end of the surgery, P/F ratio decreased to 263 with yellow frothy sputum in the endotracheal tube and we diagnosed re-expansion pulmonary edema based on appearing yellow frothy sputum and chest X-ray. No recruitment procedure was carried out through the course except positive pressure ventilation with 5 cmH2O of PEEP in the intensive care unit after surgery. Twelve hours after the surgery, we could not confirm the recovery of lung volume on chest X-ray; however the patient was extubated because of P/F ratio increasing to 507. After 8 days of the surgery, the chest X-ray showed recovery of the lung volume to almost normal size. In this case, the compressed lung needed almost 1 week to recover the lung volume. This change in chest X-ray might indicate inadequate recovery of lung volume by recruitment maneuver and this should be avoided in order not to allow development of unfavorable clinical course of RPE.

[Incidence and characteristics of perioperative pulmonary thromboembolism in Japan from 2009 through 2011 -the results of perioperative pulmonary thromboembolism research by the Japanese society of anesthesiologists (JSA-PTE research) --].

BACKGROUND: This study was designed to investigate the annual incidence and characteristics of perioperative pulmonary thromboembolism (PTE) in Japan from 2009 through 2011, and to compare the current trend with that observed in our previous studies conducted since 2002. METHODS: In the 3-year study period, a questionnaire was annually mailed to all institutions certified as training hospitals for anesthesiologists by the Japanese Society of Anesthesiologists (JSA). The survey included the parameters of age, sex, type of surgery, and the risk factors in patients who were operated upon. RESULTS: The questionnaire was sent out to total of 3,556 institutions and obtained answers from 2,511 institutions (70.6%) in the 3-year study period. Total 4,432,538 surgeries were conducted and 1,300 cases (0.03%) of perioperative PTE were registered. The incidence of PTE in all the 3 years was significantly lower than that observed in 2002-2003 (P<0.01). In addition, the mortality in 2011 was also significantly lower than that in 2002-2003 (P<0.05). The incidence of PTE in females (0.04%) was twice of the incidence of males (0.02%). The types of surgery with higher incidence of perioperative PTE were "thoracotomy with laparotomy" (0.08%),"hip joint, limbs" (0.07%) and"craniotomy" (0.06%). Compared with the middle age group (19-65 year-old), the incidence of PTE was twice in the elderly's (66-85 year-old) and in the super-elderly (over 86 year-old) it was thrice. In this survey, most approved risk factors were obesity (44%), malignancy (35%) and long term bed-rest (26%), and the ratio of long term bed-rest was decreasing compared with 2008. In the PTE cases, the ratio of the patients who received anticoagulant drugs (29-30%) or IVC filters placement (4-5%) increased compared with the results of JSA-PTE research in 2008 (P<0.01). CONCLUSIONS: The incidence and mortality of perioperative PTE decreased;although the factor of decrease in an incidence was considered to be the result of preventive method, as in the decrease in the mortality, the survey should be continued.

Current prevention practice for venous thromboembolism in Japanese intensive care units.

Venous thromboembolism (VTE) is a well-recognized life-threatening complication in the intensive care unit (ICU). However, no data have been reported regarding the prevalence and methods of prevention of VTE in Japanese ICUs. This study aimed to document the current practice of VTE prevention across a broad sample of medical-surgical ICU patients in Japan. In November 2010, we performed a point-prevalence survey of Japanese ICUs in training facilities for intensive care specialists. We recorded data from five consecutive ICU patients in each facility at any time on the day of the survey. A total of 470 patients were registered in this study. VTE prophylaxis was received by 85.3 % of participants. Of these, 69.8 % received mechanical prophylaxis and 12.5 % received pharmacological methods, with 17.7 % receiving both methods. Analyzing a comparison of the presence or absence of a hospital prevention protocol, the protocol group had higher rates of receiving prophylaxis (88.8 % vs. 80.0 %, P < 0.01) than the no-protocol group. In conclusion, VTE prophylaxis by mechanical methods was the main method in a high number of medical-surgical ICU patients in Japan. The ICUs with a hospital VTE prevention protocol in place performed significantly higher rates of prophylaxis than those without a protocol.

SK2 channels are neuroprotective for ischemia-induced neuronal cell death.

In mouse hippocampal CA1 pyramidal neurons, the activity of synaptic small-conductance Ca(2+)-activated K(+) channels type 2 (SK2 channels) provides a negative feedback on N-methyl-D-aspartate receptors (NMDARs), reestablishing Mg(2+) block that reduces Ca(2+) influx. The well-established role of NMDARs in ischemia-induced excitotoxicity led us to test the neuroprotective effect of modulating SK2 channel activity following cerebral ischemia induced by cardiac arrest and cardiopulmonary resuscitation (CA/CPR). Administration of the SK channel positive modulator, 1-ethyl-benzimidazolinone (1-EBIO), significantly reduced CA1 neuron cell death and improved CA/CPR-induced cognitive outcome. Electrophysiological recordings showed that CA/CPR-induced ischemia caused delayed and sustained reduction of synaptic SK channel activity, and immunoelectron microscopy showed that this is associated with internalization of synaptic SK2 channels, which was prevented by 1-EBIO treatment. These results suggest that increasing SK2 channel activity, or preventing ischemia-induced loss of synaptic SK2 channels, are promising and novel approaches to neuroprotection following cerebral ischemia.

Sex difference in sensitivity to allopregnanolone neuroprotection in mice correlates with effect on spontaneous inhibitory post synaptic currents.

Allopregnanolone (ALLO) is a neurosteroid that has many functions in the brain, most notably neuroprotection and modulation of gamma-amino butyric acid (GABA) neurotransmission. Using a mouse model of cardiac arrest and cardiopulmonary resuscitation, we have previously demonstrated that ALLO protects cerebellar Purkinje cells (PCs) from ischemia in a GABA(A) receptor-dependent manner. In this study we examined the effect of sex on ALLO neuroprotection, observing that low dose ALLO (2 mg/kg) provided greater neuroprotection in females compared to males. At a higher dose of ALLO (8 mg/kg), both sexes were significantly protected from ischemic damage. Using an acute cerebellar slice preparation, whole cell voltage clamp recordings were made from PCs. Spontaneous inhibitory post synaptic currents (IPSCs) were analyzed and the response to physiological ALLO (10 nM) was significantly greater in female PCs compared to male. In contrast, recordings of miniature IPSCs, did not exhibit a sex difference in response to ALLO, suggesting that ALLO affects males and females differentially through a mechanism other than binding postsynaptic GABA(A) receptors. We conclude that the female brain has greater sensitivity to ALLO mediated potentiation of GABAergic neurotransmission, contributing to increased neuroprotection.

[Incidence and clinical characteristics of perioperative pulmonary thromboembolism in Japan in 2008--results from the annual study of Japanese Society of Anesthesiologists, Committee on Patient Safety and Risk Management, Perioperative Pulmonary Thromboembolism Working Group].

BACKGROUND: The Japanese Society of Anesthesiologists (JSA) has maintained records of the annual incidence and characteristics of perioperative pulmonary thromboembolism (perioperative PTE) since 2002. The aim of this paper was to provide recent results of the JSA annual study conducted in 2008, and to determine the current factors that tend to prevent perioperative venous thromboembolism (VTE) in Japan. METHODS: A comprehensive questionnaire designed by the JSA PTE working group was mailed to all institutions certified as teaching hospitals by JSA. The data tics of patients with perioperative PTE, such as types of diseases and surgeries, age, sex, methods used for the prevention of VTE (in some cases), and prognosis of perioperative PTE. RESULTS: The rate of effective responses was 56.1% (634/1116), and 1,177,626 surgeries were registered during the study period. There were 324 patients who were reported to have had PTE, and the incidence was 2.75 per 10,000 surgeries. The incidence of perioperative PTE in 2008 did not change significantly from that in 2005-07. The surgeries that most commonly resulted in perioperative PTE were limb and/or hip joint surgery (5.71 per 10,000 surgeries), craniotomy (4.64 per 10,000), and thoracotomy with laparotomy (3.46 per 10,000 surgeries). The mortality rate of perioperative PTE in 2008 was found to have significantly decreased from that in 2005-07 (15.6% vs. 22.4%; P = 0.01). Further, the rate of patients who received anticoagulant drugs in 2008 was significantly higher than that in 2005-07 (17.6% vs. 10.8%; P = 0.0018). Individual guidelines for the prevention of perioperative VTE were adopted in 55.4% of the training institutions. CONCLUSIONS: The increase in the percentage of patients who received anticoagulant drugs around the time of the operation, and the decreased mortality of patients with perioperative PTE suggested that the prophylaxis for perioperative VTE with anticoagulant drugs reduces perioperative mortality.