Air travel and the risk of thromboembolism

Hearts in the sky: understanding the cardiovascular implications of air travel

Air travel is widely regarded as the safest mode of transportation, with the United States leading in airline passengers. However, travelers with pre-existing heart conditions face acute cardiovascular risks. Flight pilots and cabin crew are particularly vulnerable to air travel's physiological changes, which can significantly impair their health and performance. Cabin pressure differences and reduced oxygen levels at cruising altitudes of 5000-8000 feet make air travel challenging for individuals with underlying cardiac and pulmonary problems. This, along with dry air, sleep deprivation, missed medication and prolonged sitting, can lead to physiological changes. In-flight and pre-flight stressors contribute to increased health issues, and studies show a rise in medical emergencies during flights. Prolonged exposure to the airplane environment can lead to various health issues for pilots and cabin crew. These changes include impaired judgment, cognitive function and discomfort in the sinuses and ears due to pressure differentials. Therefore, thorough medical screening, skilled instrument use and compliance with safety measures are essential to mitigate these risks. This article reviews the cardiac implications of air travel, discussing the underlying pathophysiology, associated risks and preventive measures to ensure safer flights for individuals with cardiovascular diseases.

Comparison of machine learning models to predict the risk of breast cancer-related lymphedema among breast cancer survivors: a cross-sectional study in China

Objective

The aim of this study was to develop and validate a series of breast cancer-related lymphoedema risk prediction models using machine learning algorithms for early identification of high-risk individuals to reduce the incidence of postoperative breast cancer lymphoedema.

Methods

This was a retrospective study conducted from January 2012 to July 2022 in a tertiary oncology hospital. Subsequent to the collection of clinical data, variables with predictive capacity for breast cancer-related lymphoedema (BCRL) were subjected to scrutiny utilizing the Least Absolute Shrinkage and Selection Operator (LASSO) technique. The entire dataset underwent a randomized partition into training and test subsets, adhering to a 7:3 distribution. Nine classification models were developed, and the model performance was evaluated based on accuracy, sensitivity, specificity, recall, precision, F-score, and area under curve (AUC) of the ROC curve. Ultimately, the selection of the optimal model hinged upon the AUC value. Grid search and 10-fold cross-validation was used to determine the best parameter setting for each algorithm.

Results

A total of 670 patients were investigated, of which 469 were in the modeling group and 201 in the validation group. A total of 174 had BCRL (25.97%). The LASSO regression model screened for the 13 features most valuable in predicting BCRL. The range of each metric in the test set for the nine models was, in order: accuracy (0.75-0.84), sensitivity (0.50-0.79), specificity (0.79-0.93), recall (0.50-0.79), precision (0.51-0.70), F score (0.56-0.69), and AUC value (0.71-0.87). Overall, LR achieved the best performance in terms of accuracy (0.81), precision (0.60), sensitivity (0.79), specificity (0.82), recall (0.79), F-score (0.68), and AUC value (0.87) for predicting BCRL.

Conclusion

The study established that the constructed logistic regression (LR) model exhibits a more favorable amalgamation of accuracy, sensitivity, specificity, recall, and AUC value. This configuration adeptly discerns patients who are at an elevated risk of BCRL. Consequently, this precise identification equips nurses with the means to undertake timely and tailored interventions, thus averting the onset of BCRL.

Altitude-Related Venous Thrombosis With Heart Disease: An Updated Review

Altitude-related venous thrombosis (ARVT) is a condition of growing concern among individuals engaged in high-altitude travel and activities. This updated review explores the epidemiology, pathophysiological mechanisms, clinical presentations, and management of ARVT based on a thematic analysis and synthesis of the existing literature. ARVT's multifactorial etiology involves the interplay of hypobaric hypoxia and endothelial dysfunction, creating a procoagulant state and increasing the risk of thrombosis. Common clinical manifestations include pain, swelling, and redness in the extremities, necessitating accurate and timely diagnosis, particularly in remote settings. Thromboprophylaxis during high-altitude travel and activities plays a crucial role in reducing the risk of ARVT, while anticoagulation remains the mainstay of management. Further research is needed to optimize preventive and treatment strategies, enhancing patient outcomes and safety in high-altitude environments.

Prolonged Fasting as a Cause of Deep Vein Thrombosis: A Case Report

Background  Intermittent fasting is becoming more popular as health benefits are described in recent literature. Various forms of fasting exist, one of them involving a zero-calorie diet and drinking only water. However, the safety of water-only fasting is still not well established. We report a case of a man who developed a lower limb deep vein thrombosis at the end of a 2-week water-only fasting and characterized by an initial period of 5 days of no food and no water intake. We reviewed literature regarding potential links between fasting and venous thromboembolism (VTE). Clinical Approach  We believe that fasting can induce important dehydration, leading to hypercoagulability and then contribute to the development of a venous thrombosis. The patient was treated with apixaban for 3 months as is recommended in patients with a provoked event caused by a transient risk factor. No thrombotic recurrence was observed during the 6-month follow-up. Conclusion  The public needs to be aware of the potential life-threatening complications associated with important dehydration in the setting of medically unsupervised fasting, and these might include VTE. Whether a VTE with dehydration as the only identified risk factor should be approached as a low recurrence risk situation or not still needs to be clarified.

Extensive Lower Limb Deep Vein Thrombosis Provoked by Gastroenteritis-Induced Dehydration: A Case Report for Unusual Precipitating Factor

The incidence of deep vein thrombosis (DVT) has been related to a number of risk factors, including genetic and acquired prothrombotic conditions, infections, inflammatory diseases, hematologic disorders, trauma, and drug use. Dehydration is a known independent risk factor for the development of thrombosis; however possibly insufficient evidence to form a strong association. The purpose of this case report is to present a 30-year-old male with DVT provoked by acute gastroenteritis-induced dehydration. The patient presented to the emergency department (ED) with a recent history of watery diarrhea for four days, for which he was diagnosed with gastroenteritis and managed at an outpatient care facility. The patient visited the ED again with a complaint of a one-day history of progressively worsening continuous pain in his left lower calf associated with swelling. The ultrasound-Doppler/duplex scan for the left lower limb venous system showed negative augmentation signs and non-compressibility of the deep venous system with partial occlusion/echogenic thrombosis extending from the external iliac vein, saphenofemoral junction, superficial femoral vein, popliteal vein, anterior tibial vein, and posterior tibial artery vena comitans. The patient was diagnosed with acute extensive DVT (multiple emboli). Patient care (medical treatment plan/therapeutic anticoagulation) was started in the ED and continued in the Critical Care Unit for close monitoring and care for a couple of days, after which he was transferred to the ward and then discharged in stable condition. He was prescribed a three-month course of appropriate medication regimen. This rare case presentation is a reminder to emergency physicians that dehydration might induce DVT and all patients, regardless of age, diagnosis or comorbidities, should always be risk assessed upon presentation and discharge, and prophylaxis should be provided according to their risk profile.

Nephrotic Syndrome – Different Risk of Venous Thromboembolism with Different Approaches to Justify Prophylactic Anticoagulation

All of the circumstances influencing any of the elements of Virchow’s Triad can increase the risk of venous thromboembolism. Assessing prothrombotic factors can sometimes be difficult. One of the examples of such a condition is nephrotic syndrome. In this condition at least two elements of Virchow’s triad are affected: physiological blood composition and the venous blood flow which is slowed down by the edema. Except for the cases mentioned in KDIGO (Kidney Disease: Improving Global Outcomes), the use of anticoagulant drugs in the prophylaxis of VTE (Venous Thromboembolism) in nephrotic syndrome seems unclear. Nevertheless, due to the increased risk of VTE, it is worth implementing mechanical anticoagulant prophylaxis, which can also improve the quality of life of patients by reducing swelling. The article analyzes the current knowledge on the field and gives some proposals with low bleeding risk.

Addressing Common Questions About Traveling by Air After Orthopedic Surgery

Many patients have questions about traveling by air after orthopedic surgery. The goal of this review was to provide a guide to addressing these issues to better prepare patients for air travel. A comprehensive literature review was conducted to address patient questions regarding metal detectors, as well as deep venous thrombosis risk with flying. Further, patient questions pertaining to specific airlines, airports, and Transportation Security Administration policies were answered through direct discussion with representatives, website review, and internet research. Ultimately, providers should be aware of the many challenges that orthopedic patients face during air travel, and patients should consult their providers before making travel plans. Airline passengers are likewise encouraged to equip themselves with the information presented in this article, to best advocate for themselves. This guide should be used as a reference tool, providing up-to-date information about air travel after orthopedic surgery to both patients and providers alike. [Orthopedics. 2021;44(6):e719-e723.].

Upper Extremity Superficial Vein Thromboses Presenting as Acute Neck Pain in a Young and Healthy Male: A Case Report

BACKGROUND AND PURPOSE

Neck pain in the United States is pervasive and contributes to disability. While the majority of neck pain in young and healthy individuals is neuromusculoskeletal in nature, screening for red flags is necessary for ruling-out serious medical pathologies. The purpose of this case report is to describe a young and healthy male subject with a primary complaint of acute neck pain with multiple underlying upper extremity superficial vein thromboses (UESVTs).

CASE DESCRIPTION

The subject was a 27-year-old male active-duty Soldier referred to physical therapy by his primary care provider (PCP) for acute left-sided neck pain. Prior to physical therapy, the subject had been treated with cyclobenzaprine, oxycodone-acetaminophen, trigger point injection and had undergone a D-dimer to rule out a potential thrombus due to air travel and lower extremity immobilization.

OUTCOMES

The subject underwent a D-dimer, Doppler ultrasound, pharmacological treatment of Rivaroxaban, and was referred to hematology/oncology to rule out systemic causes of SVTs. Evidence of subtle increases in blood pressure over the course of three months, a positive D-dimer, and symptoms incongruent with clinical presentation contributed to referral to a hematology/oncology specialist and a diagnosis of multiple UESVTs. The subject was able to return to his previous level of activity by six months and remained free of SVTs at two-year follow-up.

DISCUSSION

UESVT events are rare and can be challenging to identify. This case report describes a unique presentation of acute neck pain caused by underlying UESVTs in an otherwise healthy and active young male.

LEVEL OF EVIDENCE

Level 4.

Lower limb venous and arterial peripheral diseases and work conditions: systematic review

OBJECTIVES

The individual peripheral vascular disease risk factors are well documented, but the role of work conditions remains equivocal. This systematic review aims to assess relationships between lower limb peripheral venous diseases (lower limb varicose veins (LLVV), venous thromboembolism (VTE) comprising deep vein thrombosis and pulmonary embolism), peripheral arterial disease (intermittent claudication, aortic dissection, aortic aneurysm) and occupational constraints among working adults.

METHODS

Several databases were systematically searched until February 2019 for observational studies and clinical trials. Preferred Reporting Items for Systematic Reviews and Meta-Analyses method was used for article selection. Quality assessment and risk of bias were evaluated using Strengthening the Reporting of Observational Studies in Epidemiology and Newcastle-Ottawa scales.

RESULTS

Among the 720 screened articles, 37 remained after full-text evaluation. Among the 21 studies on LLVV, prolonged standing was significantly associated to a higher risk of varicose veins with a threshold probably around >3 to 4 hours/day but exposure duration in years was not sufficiently considered. Seated immobility was often observed in workers, with no sufficient evidence to prove that prolonged sitting at work is related to VTE. Carrying heavy loads, stress at work and exposure to high temperatures have emerged more recently notably in relation to varicose veins but need to be better explored. Only three studies discussed the potential role of work on peripheral arterial disease development.

CONCLUSIONS

Although some observational studies showed that prolonged standing can be related to varicose veins and that seated immobility at work could be linked to VTE, very little is known about peripheral arterial disease and occupational constraints. Clinical trials to determine preventive strategies at work are needed.

PROSPERO REGISTRATION NUMBER

CRD42019127652.

A scoring system for predicting the risk of breast cancer-related lymphedema

Objective

We aimed to establish a scoring system to predict the risk of breast cancer-related lymphedema.

Methods

From April 2017 to December 2018, 533 patients who previously underwent surgery for breast cancer were enrolled in this cross-sectional study. Univariate analysis was performed to explore and define the risk factors. A scoring system was then established on the basis of odds ratio values in the regression analysis.

Results

The additive scoring system values ranged from 6 to 22. The receiver operating characteristic (ROC) curve of this scoring system showed a sensitivity and specificity of 83.3% and 57.3%, respectively, to predict the risk of lymphedema at a cut-off of 15.5 points; the area under the curve was 0.736 (95% confidence interval: 0.662–0.811), with χ² = 5.134 (P = 0.274) for the Hosmer–Lemeshow test.

Conclusions

The predictive efficiency and accuracy of the scoring system were acceptable, and the system could be used to predict and screen groups at high risk for breast cancer-related lymphedema.

Deep Vein Thrombosis in a Young, Healthy Baseball Catcher: A Case Report and Review of the Literature

Venous thromboembolism is becoming increasingly recognized as a significant cause of morbidity and mortality in the hospitalized pediatric population. However, young healthy athletes can present with unique risk factors for deep vein thrombosis (DVT) that can be overlooked. Here we report a case of an adolescent male with no inherited risk factors or prior history of DVTs who developed a right femoral vein DVT in the context of playing catcher in baseball after recovering from a bout of streptococcal pharyngitis. We review the evidence that suggests that repetitive squatting-induced compression of the femoral vein can cause the venous stasis and endothelial microtrauma that contributed to the formation of this thrombus.

In-Flight Medical Emergencies: A Review

IMPORTANCE

In-flight medical emergencies (IMEs) are common and occur in a complex environment with limited medical resources. Health care personnel are often asked to assist affected passengers and the flight team, and many have limited experience in this environment.

OBSERVATIONS

In-flight medical emergencies are estimated to occur in approximately 1 per 604 flights, or 24 to 130 IMEs per 1 million passengers. These events happen in a unique environment, with airplane cabin pressurization equivalent to an altitude of 5000 to 8000 ft during flight, exposing patients to a low partial pressure of oxygen and low humidity. Minimum requirements for emergency medical kit equipment in the United States include an automated external defibrillator; equipment to obtain a basic assessment, hemorrhage control, and initiation of an intravenous line; and medications to treat basic conditions. Other countries have different minimum medical kit standards, and individual airlines have expanded the contents of their medical kit. The most common IMEs involve syncope or near-syncope (32.7%) and gastrointestinal (14.8%), respiratory (10.1%), and cardiovascular (7.0%) symptoms. Diversion of the aircraft from landing at the scheduled destination to a different airport because of a medical emergency occurs in an estimated 4.4% (95% CI, 4.3%-4.6%) of IMEs. Protections for medical volunteers who respond to IMEs in the United States include a Good Samaritan provision of the Aviation Medical Assistance Act and components of the Montreal Convention, although the duty to respond and legal protections vary across countries. Medical volunteers should identify their background and skills, perform an assessment, and report findings to ground-based medical support personnel through the flight crew. Ground-based recommendations ultimately guide interventions on board.

CONCLUSIONS AND RELEVANCE

In-flight medical emergencies most commonly involve near-syncope and gastrointestinal, respiratory, and cardiovascular symptoms. Health care professionals can assist during these emergencies as part of a collaborative team involving the flight crew and ground-based physicians.

Venous thromboembolism prophylaxis on flights

Civil aviation has seen a steady increase in the number of scheduled flights over the last ten years and, as a result, more passengers are traveling by air. This has been associated with an increase in flight-related diseases, especially on long-haul flights. One of the most feared complications during flights is venous thromboembolism (VTE), but its true incidence is difficult to measure because of a lack of consensus on elements such as the definition of how long after landing a VTE can be considered to be related to a flight and even how long a flight must last to be considered of long duration. There has been much discussion of the pathophysiological mechanisms of flight-related VTE, of which passengers are at greatest risk, and of what prophylactic measures can be adopted safely and effectively. The purpose of this review is to clarify these points and describe current consensual conduct.

e-thrombosis: epidemiology, physiopathology and rationale for preventing computer-related thrombosis

The large availability of computers (personal, laptop and tablet) has revolutionized human life more than any other discovery or invention over the past century. Nevertheless, prolonged use of computers may both directly and indirectly promote the onset of some serious human pathologies, thus including venous thromboembolism (VTE). Convincing epidemiological and biological evidence has been published that computer-related thrombosis (also known as "e-thrombosis") should now be regarded as an independent clinical entity, deserving enhanced healthcare focus and interventions, due to the growing worldwide diffusion of computer devices, which may ultimately contribute to enhance the risk of computer-related thrombosis, and turn it from a relatively rare disease to a noticeably frequent pathology. A set of preventive measures can thus be suggested, such as designing and setting up ergonomically suitable computer workstations, using comfortable sitting positions, avoiding long and uninterrupted computer-seated immobility, and avoiding the wearing of restrictive clothing on the legs. Reinforced measures should then be advised in patients with acquired, or inherited prothrombotic conditions, in whom the risk of computer-related thrombosis may be substantially magnified.

Deep Venous Thrombosis

Deep venous thrombosis (DVT) is a frequently encountered condition that is often diagnosed and treated in the outpatient setting. Risk stratification is helpful and recommended in the evaluation of DVT. An evidence-based diagnostic approach is discussed here. Once diagnosed, the mainstay of DVT treatment is anticoagulation. The specific type and duration of anticoagulation depend upon the suspected etiology of the venous thromboembolism, as well as risks of bleeding and other patient comorbidities. Both specific details and a standardized approach to this vast treatment landscape are presented.

Foreign citizen mortality in Iceland January 2006 - December 2016

BACKGROUND

In recent years, tourism has become the number one account for foreign exchange income in Iceland, overtaking the fisheries industry and aluminium production. The rise of tourism has strongly affected Icelandic society in various sectors. With the increase of tourists visiting Iceland, the number of foreign citizens that died and were autopsied also rose.

METHOD

Data were collected from the Department of Forensic Pathology at Landspitali University Hospital in Reykjavik for the period January 2006 - December 2016.

RESULT

During this time there were 109 autopsies performed on foreign citizens of which 58 died from natural causes, 49 were injury deaths and in 2 cases no certain cause of death could be determined. Most represented were citizens from North America, United Kingdom and Germany (each 11%). The main causes of death were cardiovascular events (41%) followed by unintentional injuries (34%).

CONCLUSION

The research at hand shows the significant influence of tourism on Forensic Medicine and provides an update on deaths of overseas travellers. Furthermore this study points out variable risks of travel-related injuries and deaths in Iceland.

Thrombosis, Hypercoagulable States, and Anticoagulants

Patients with derangements of secondary hemostasis resulting from inherited or acquired thrombophilias are at increased risk of venous thromboemboli (VTE). Evaluation of a patient with suspected VTE proceeds via evidence-based algorithms that involve computing a pretest probability based on the history and physical examination; this guides subsequent work-up, which can include D dimer and/or imaging. Testing for hypercoagulable disorders should be pursued only in patients with VTE with an increased risk for an underlying thrombophilia. Direct oral anticoagulants are first-line VTE therapies, but they should be avoided in patients who are pregnant, have active cancer, antiphospholipid antibody syndrome, severe renal insufficiency, or prosthetic heart valves.

Dehydration as a Possible Cause of Monthly Variation in the Incidence of Venous Thromboembolism

BACKGROUND

Monthly or seasonal changes in the incidence of venous thromboembolism (VTE) were previously reported; however, the mechanism of such variability is not completely understood.

METHODS

In the present retrospective single-center analysis, consecutive patients with proximal deep vein thrombosis and/or pulmonary embolism (PE) diagnosed between January 2009 and December 2013 were evaluated.

RESULTS

The study population included 1496 patients, 48% men, mean age 63 ± 18 years. Most (82%) cases with VTE were provoked and 39% of patients had active cancer. Four months of peak incidence (3, 7, 10 and 11) were compared with 4 months of the lowest incidence (4, 5, 6, and 12), showing a significant difference in VTE numbers (597 vs 405 cases/year, P = 0.001). In all subgroup analyses, including gender, provoked or unprovoked event and presence or absence of cancer, significant differences between the months of peak and lowest incidence remained. Blood urea nitrogen (BUN)-creatinine ratio was significantly higher in all cases in the peak incidence group compared to the lowest incidence group (24 ± 1.5 vs 21 ± 1.6, P = 0.03). In patients with unprovoked VTE (n = 269), levels of BUN and hematocrit were significantly increased in the peak incidence group compared to lowest incidence group (19.5 ± 0.8 mg/dL vs 16 ± 1.1 mg/dL, P = 0.03; 39.2 ± 0.3% vs 37.4 ± 0.5%, P = 0.01, respectively).

CONCLUSIONS

The current study demonstrates that occurrence of VTE exhibits monthly variation also existing in patients with provoked events and even in those with cancer. Dehydration is suggested as a potential explanation to the month-related variation in incidence of VTE.

Confronting the challenges of the menopausal transition

Canada’s Generation X is now entering the menopausal transition and pursuing effective therapy for bothersome vasomotor symptoms. They do so at a time when confusion about the safe and appropriate use of menopausal hormone therapy (MHT) has never been greater. Misplaced fears among women and their health care providers about MHT have, in many circumstances, led them to abandon this most effective therapy. This review discusses the physiology of the menopausal transition, the nature of symptoms related to withdrawal of ovarian estrogen production, and the potential benefits and risks of MHT. It is now clear that for most recently menopausal women the benefits of MHT outweigh the risks. The rationale for choosing different dosages, formulations, and regimens is reviewed.

Developments in the management and treatment of pulmonary embolism

Pulmonary embolism (PE) is a serious and costly disease for patients and healthcare systems. Guidelines emphasise the importance of differentiating between patients who are at high risk of mortality (those with shock and/or hypotension), who may be candidates for thrombolytic therapy or surgery, and those with less severe presentations. Recent clinical studies and guidelines have focused particularly on risk stratification of intermediate-risk patients. Although the use of thrombolysis has been investigated in these patients, anticoagulation remains the standard treatment approach. Individual risk stratification directs initial treatment. Rates of recurrence differ between subgroups of patients with PE; therefore, a review of provoking factors, along with the risks of morbidity and bleeding, guides the duration of ongoing anticoagulation. The direct oral anticoagulants have shown similar efficacy and, in some cases, reduced major bleeding compared with standard approaches for acute treatment. They also offer the potential to reduce the burden on patients and outpatient services in the post-hospital phase. Rivaroxaban, dabigatran and apixaban have been shown to reduce the risk of recurrent venous thromboembolism versus placebo, when given for >12 months. Patients receiving direct oral anticoagulants do not require regular coagulation monitoring, but follow-up, ideally in a specialist PE clinic in consultation with primary care providers, is recommended.

Sudden Death by Pulmonary Thromboembolism due to a Large Uterine Leiomyoma with a Parasitic Vein to the Mesentery

The pathophysiology of venous thrombosis is classically attributed to alterations in one or more components of Virchow's triad: hypercoagulability, stasis, and damage to the vascular endothelium. Deep vein thrombosis (DVT) may lead to pulmonary thromboembolism (PE), and the latter is culpable for many deaths annually in the United States; however, DVT as a complication of uterine leiomyoma has rarely been reported. We report a case of a 57-year-old woman whose death was due to a large pedunculated subserosal leiomyoma externally compressing the pelvic veins resulting in stasis and venous thrombosis leading to fatal PE. The association of large pelvic masses with venous thrombosis has clinical implications, since prophylactic surgery could be life-saving.

Comparison of four scores to predict major bleeding in patients receiving anticoagulation for venous thromboembolism: findings from the RIETE registry

Stratification of the individual bleeding risk prior to initiation of anticoagulation in patients with acute venous thromboembolism (VTE) has the potential to assist clinicians in making decisions about the proper intensity and duration of antithrombotic therapy. It is unclear which of the validated and internationally accepted scores recommended for the achievement of this important task has the best predictive value. We compared the predictive value of four validated scores (by Landefeld, Beyth, Kuijer and Ruiz-Gimenez, respectively) for the development of major bleeding complications occurring in the first 3 months in patients with acute VTE treated with conventional anticoagulation. Based on the population of RIETE Registry (international registry of patients with acute VTE), we identified those patients presenting all the required prognostic variables, and then calculated the ability of each score for predicting the bleeding risk. Of 40,265 eligible patients, we identified 8,717 meeting the recruitment criteria. Overall, 0.9 % of patients experienced at least one episode of major bleeding within 90 days of the index event. The proportion of patients classified as having a low risk varied between 1.2 and 3.7 %, that of patients having an intermediate risk between 76 and 93 %, and that of patients classified as having a high risk between 6.1 and 18 %. The area under the receiver operating characteristic ranged between 0.55 and 0.60, the positive predictive value between 1.5 and 3.2, and the likelihood ratio between 0.72 and 1.59. In conclusion, all four scores show a very low ability to predict the bleeding risk in patients with acute VTE undergoing conventional anticoagulation.

Angiophagy: clearing or clogging microvessels?

The body clears small clots from blood vessels through a process called angiophagy, opening up new approaches to combat cerebral and cardiac microvascular occlusive diseases (Grutzendler et al., this issue).

Effects of 6-h exposure to low relative humidity and low air pressure on body fluid loss and blood viscosity

The purpose of this study was to investigate the effects of 6-h exposure to low relative humidity (RH) and low air pressure in a simulated air cabin environment on body fluid loss (BFL) and blood viscosity. Fourteen young healthy male subjects were exposed to four conditions, which combined RH (10% RH or 60% RH) and air pressure (NP: sea level or LP: equivalent to an altitude of 2000 m). Subjects remained seated on a chair in the chamber for 6 h. Their diet and water intake were restricted before and during the experiment. Insensible water loss (IWL) in LP10% condition was significantly greater than in NP60% condition; thus, combined 10%RH and LP conditions promoted a greater amount of IWL. The BFL under the LP condition was significantly greater than that under the NP condition. Blood viscosity significantly increased under LP conditions. Increases in red blood cell counts (RBCs) and BFL likely contributed to the increased blood viscosity. These findings suggest that hypobaric-induced hypoxia, similar to the conditions in the air cabin environment, may cause increased blood viscosity and that the combined low humidity and hypobaric hypoxia conditions increase IWL.

Health problems awareness during travel among faculty members of a large university in Latin America: preliminary report

Health safety during trips is based on previous counseling, vaccination and prevention of infections, previous diseases or specific problems related to the destination. Our aim was to assess two aspects, incidence of health problems related to travel and the traveler's awareness of health safety. To this end we phone-interviewed faculty members of a large public University, randomly selected from humanities, engineering and health schools. Out of 520 attempts, we were able to contact 67 (12.9%) and 46 (68.6%) agreed to participate in the study. There was a large male proportion (37/44, 84.1%), mature adults mostly in their forties and fifties (32/44, 72.7%), all of them with higher education, as you would expect of faculty members. Most described themselves as being sedentary or as taking occasional exercise, with only 15.9% (7/44) taking regular exercise. Preexisting diseases were reported by 15 travelers. Most trips lasted usually one week or less. Duration of the travel was related to the destination, with (12h) or longer trips being taken by 68.2% (30/44) of travelers, and the others taking shorter (3h) domestic trips. Most travelling was made by air (41/44) and only 31.8% (14/44) of the trips were motivated by leisure. Field research trips were not reported. Specific health counseling previous to travel was reported only by two (4.5%). Twenty seven of them (61.4%) reported updated immunization, but 11/30 reported unchecked immunizations. 30% (9/30) reported travel without any health insurance coverage. As a whole group, 6 (13.6%) travelers reported at least one health problem attributed to the trip. All of them were males travelling abroad. Five presented respiratory infections, such as influenza and common cold, one neurological, one orthopedic, one social and one hypertension. There were no gender differences regarding age groups, destination, type of transport, previous health counseling, leisure travel motivation or pre-existing diseases. Interestingly, the two cases of previous health counseling were made by domestic travelers. Our data clearly shows that despite a significant number of travel related health problems, these highly educated faculty members, had a low awareness of those risks, and a significant number of travels are made without prior counseling or health insurance. A counseling program conducted by a tourism and health professional must be implemented for faculty members in order to increase the awareness of travel related health problems.

Cancer-related coagulopathy (Trousseau's syndrome): review of the literature and experience of a single center of internal medicine

Venous thromboembolism (VTE) occurs roughly in one out of five cancer patients and is the second cause of death in this population. When all cancer patients are considered together, a sevenfold increased risk for VTE has been calculated. Over the last 20 years, a number of risk factors have been recognized. These have been used in several risk assessment models aimed at identifying high-risk patients who are therefore candidates for thromboprophylaxis. An easily applicable and reliable risk score is based on the cancer site, hemoglobin levels, pre-chemotherapy platelet and leukocyte counts as well as body mass index. The additional measurement of two biomarkers, namely D-dimer and soluble P-selectin, may improve estimates of the cumulative VTE probability. A variable incidence of VTE has been determined in patients with specific types of malignancy, with the highest odds in those with pancreatic cancer followed by head and neck tumors. In terms of histotype, the risk of VTE is significantly higher in patients with adenocarcinoma than in those with squamous cell carcinoma and in patients with high-grade versus low-grade tumors. Cancer therapy may also be responsible for VTE; specifically, the presence of an indwelling central venous catheter, immunomodulatory drugs such as thalidomide and lenalidomide, monoclonal antibodies, such as bevacizumab, erythropoiesis-stimulating agents and hormonal therapy with tamoxifen place patients at higher risk. The pathogenesis of cancer-related VTE is poorly understood but is likely to be multifactorial. "Virchow's triad," comprising stasis consequent to a decreased blood flow rate, an enhanced blood clotting tendency such as accompanies inflammation and growth factor expression, and structural modifications in blood vessel walls, is thought to play a central role in the induction of VTE. The prophylaxis and treatment of VTE are based on well-established drugs such as vitamin K antagonists and unfractionated and low-molecular-weight heparins as well as on an expanding group of new oral anticoagulants, including fondaparinux, rivaroxaban, apixaban and dabigatran. Furthermore, aspirin has been shown to prevent arterial thrombosis and to reduce the rate of major vascular events. Guidelines for the general management of VTE in cancer patients and in those with an indwelling central venous catheter have been recently developed with the aim of selecting the most rational therapeutic approach for each clinical situation. The main features of VTE based on our own observations of 92 cancer patients and 159 patients with non-neoplastic disease are briefly described herein.

Activity restrictions after gynecologic surgery: is there evidence?

Many surgeons recommend rest and restricting activities to their patients after surgery. The aim of this review is to summarize the literature regarding types of activities gynecologic surgeons restrict and intra-abdominal pressure during specific activities and to provide an overview of negative effects of sedentary behavior (rest). We searched PubMed and Scopus for years 1970 until present and excluded studies that described recovery of activities of daily living after surgery as well as those that assessed intra-abdominal pressure for other reasons such as abdominal compartment syndrome and hypertension. For our review of intra-abdominal pressure, we excluded studies that did not include a generally healthy population, or did not report maximal intra-abdominal pressures. We identified no randomized trial or prospective cohort study that studied the association between postoperative activity and surgical success after pelvic floor repair. The ranges of intra-abdominal pressures during specific activities are large and such pressures during activities commonly restricted and not restricted after surgery overlap considerably. There is little concordance in mean peak intra-abdominal pressures across studies. Intra-abdominal pressure depends on many factors, but not least the manner in which it is measured and reported. Given trends towards shorter hospital stays and off work intervals, which both predispose women to higher levels of physical activity, we urge research efforts towards understanding the role of physical activity on recurrence of pelvic organ prolapse and urinary incontinence after surgery.

Idiopathic pulmonary thromboembolism in the course of intensive psychiatric inpatient care: case report and treatment guidelines

Idiopathic thromboembolism can occur in psychiatric patients who have been inactive during a period of inpatient hospital treatment. These patients are usually treated with antipsychotic medication which has also been reported to increase risk for thromboembolic disease. Here the authors describe a patient with neither prior history of thromboembolism nor any medical risk factors for thromboembolic disease, who was admitted with an acute relapse of psychotic illness. During the course of her intensive psychiatric treatment, she had chest pain and CT-pulmonary arteriogram revealed bilateral lower lobe pulmonary embolism. She was anticoagulated and made a full medical recovery. Treatment with high dosages of typical and atypical antipsychotic medication and a lack of mobility related to intensive nursing care and sedation were likely risk factors in her development of pulmonary emboli.

Lower extremity deep venous thrombosis with fatal pulmonary thromboembolism caused by benign pelvic space-occupying lesions--an overview

Venous stasis predisposes to thrombosis. One hundred and sixty cases of fatal pulmonary thromboembolism were reviewed to determine how many cases had deep venous thromboses associated with venous blood flow reduction caused by external pressure from benign pelvic masses. Three cases were identified, representing 2% of cases overall (3/160): a 44-year-old woman with a large uterine leiomyoma (1048 g); a 74-year-old man with prostatomegaly and bladder distension (containing 1 L of urine); and a 70-year-old man with prostatomegaly and bladder distension (containing 3 L of urine). Although a rare cause of fatal deep venous thrombosis and pulmonary thromboembolism, space-occupying pelvic lesions can lead to extrinsic pressure on adjacent veins reducing blood flow and causing stasis and thrombosis. Individuals with large pelvic masses may, therefore, be at increased risk of pulmonary thromboembolism from deep venous thrombosis, particularly in the presence of concurrent risk factors such as immobility, thrombophilias, malignancy, and significant cardiopulmonary disease.

[Risk of deep venous thrombosis during an air flight: prevention and counselling at the counter]

Worldwide air traffic reaches about 2.3 billion passengers per year. The increasing number of persons at thrombo-embolic risk, together with potentially severe or fatal complications of deep venous thrombosis, suggests community pharmacists can give basic preventive advice to persons identified as at risk.

Deep vein thrombosis: a clinical review

Background:

Deep vein thrombosis (DVT) is the formation of blood clots (thrombi) in the deep veins. It commonly affects the deep leg veins (such as the calf veins, femoral vein, or popliteal vein) or the deep veins of the pelvis. It is a potentially dangerous condition that can lead to preventable morbidity and mortality.

Aim:

To present an update on the causes and management of DVT.

Methods:

A review of publications obtained from Medline search, medical libraries, and Google.

Results:

DVT affects 0.1% of persons per year. It is predominantly a disease of the elderly and has a slight male preponderance. The approach to making a diagnosis currently involves an algorithm combining pretest probability, D-dimer testing, and compression ultrasonography. This will guide further investigations if necessary. Prophylaxis is both mechanical and pharmacological. The goals of treatment are to prevent extension of thrombi, pulmonary embolism, recurrence of thrombi, and the development of complications such as pulmonary hypertension and post-thrombotic syndrome.

Conclusion:

DVT is a potentially dangerous condition with a myriad of risk factors. Prophylaxis is very important and can be mechanical and pharmacological. The mainstay of treatment is anticoagulant therapy. Low-molecular-weight heparin, unfractionated heparin, and vitamin K antagonists have been the treatment of choice. Currently anticoagulants specifically targeting components of the common pathway have been recommended for prophylaxis. These include fondaparinux, a selective indirect factor Xa inhibitor and the new oral selective direct thrombin inhibitors (dabigatran) and selective factor Xa inhibitors (rivaroxaban and apixaban). Others are currently undergoing trials. Thrombolytics and vena caval filters are very rarely indicated in special circumstances.