Long-haul air travel before major surgery: a prescription for thromboembolism?

Jobs encompassing prolonged sitting in cramped positions and risk of venous thromboembolism: cohort study

OBJECTIVES

There is mounting evidence that prolonged cramped sitting in connection with long-lasting air travel increases the risk of deep vein thrombosis of the legs and pulmonary embolism, i.e. venous thromboembolism (VTE). Prolonged cramped sitting may occur even in various jobs unrelated to air travel, and, theoretically, be associated with an increased risk of VTE. The issue is unsettled.

DESIGN

A dynamic cohort study (open for both entry and departure) in Danish national registers 1997-2006.

PARTICIPANTS

20-59-year-old manual workers. The cohort consisted of an exposed group with job functions basically characterised as sedentary (n = 105,564) and a control group with more dynamic work (n = 283,966).

SETTING

Denmark.

MAIN OUTCOME MEASURES

Deaths and hospital contacts due to pulmonary embolism and deep vein thrombosis.

RESULTS

Compared with occupations characterized by dynamic physical activity, the group encompassing those who would potentially be exposed to prolonged sitting in ergonomically adverse positions, had a significantly higher risk of pulmonary embolism (n = 77, relative risk 1.28; 95% CI 0.97-1.67, P = 0.04 in one-sided test). With respect to deep vein thrombosis they had a slightly but not significantly higher risk (n = 256, relative risk 1.09; 95% CI 0.94-1.26, P = 0.12).

CONCLUSION

Despite the crude method used allowing for no control of individual risk factors, occupations encompassing longer and shorter periods of sitting in potentially adverse ergonomic positions, i.e. cramped sitting, had a higher risk of VTE, than a socioeconomically comparable group with more dynamic physical work demands.

[Physical exposure by travelling]

Approximately 40 million Germans travel abroad every year. Air travel is the most frequently used mean of transportation followed by the automobile. During airplane flights rheumatic patients are subjected to numerous physical, biological and climatic factors which can cause stress and adverse effects on general health. Therefore, preventive strategies are helpful to protect against health damage, provided that there is general fitness for air travel. The present article focuses on physical and biological stress as well as psychological aspects during air travel and reviews prophylactic measures.

International medical travelers, length of stay, and the continuum of care: inquiry and comparison

PURPOSE

In this study, we assess whether length of stay (LOS) is associated with patient geographic origin and whether payment source for international patients explains differences in LOS.

METHODS

We used a retrospective case-control study to compare inbound international patients coming to the United States and domestic patients, who were admitted to academic medical centers (AMCs) between October 2005 and September 2008. International patients were matched to domestic patients on the basis of age, gender, AMC, admission status, severity of illness (SOI), and Medicare Severity Diagnosis-Related Group.

RESULTS

International patients stayed significantly longer than domestic patients, with an average LOS of 6.9 days (SD = 14.0) compared with 6.0 days (SD = 5.3) for domestic patients (P < .001). There was no difference in LOS between patients with international commercial and international self-pay payment sources (P = .108). Results of the multivariate analysis showed that international patients with extreme SOI stayed 21% longer than otherwise similar domestic patients with extreme SOI (P = .012).

CONCLUSIONS

The most complex international patients coming to US AMCs have substantially longer LOS than the most complex domestic patients, even after controlling for demographic characteristics, and type of condition. More research is needed to understand the underlying drivers of these differences.

Is thrombophilia a major risk factor for deep vein thrombosis of the lower extremities among Lebanese patients?

Aim

Factor V Leiden (R506Q) mutation is the most commonly observed inherited genetic abnormality related to vein thrombosis. Lebanon has one of the highest frequencies of this mutation in the world with a prevalence of 14.4% in the general population. The aim of this study is to define risk factors including inherited genetic abnormalities among Lebanese patients with lower extremity deep vein thrombosis. We report the clinical outcome of patients with thrombophilia.

Methods

From January 1998 to January 2008, 162 patients (61 males and 101 females) were diagnosed with lower extremity deep vein thrombosis. Mean age was 61 years (range: 21 to 95 years).

Results

The most frequent risk factors for vein thrombosis were surgery, advanced age, obesity, and cancer. Twenty-five patients had thrombophilia, 16 patients had factor V Leiden (R506Q) mutation, and seven patients had MTHFR C677T mutation. Ninety-two percent of patients screened for thrombophilia were positive. Screening was requested in young patients (16), patients with recurrent (11), spontaneous (8), and extensive (5) venous thrombosis, familial history (5), pregnancy (4), estroprogestative treatment (3), and air travel (1). Nine patients had one, 11 patients had two, and five had three of these conditions. Follow-up (6 to 120 months) of these 25 patients treated with antivitamin K did not reveal recurrences or complications related to venous thromboembolism.

Conclusion

Factor V Leiden mutation followed by MTHFR mutation are the most commonly observed genetic abnormalities in these series. Defining risk factors and screening for thrombophilia when indicated reduce recurrence rate and complications. Recommendations for thrombophilia screening will be proposed.

Medical tourism

Searches of the literature or Internet using the term "medical tourism" produce two sets of articles: travel for the purpose of delivering health care or travel for the purpose of seeking health care. The first usage primarily appears in the medical literature and is beyond the scope of this article, which focuses on travel to seek health care. Still, there are some aspects these two topics have in common: both are affected by ease and speed of international travel and communication associated with globalization, and both raise questions about continuity of care as well as issues related to cultural, language, and legal differences; both also raise questions about ethics. This article describes some of the motivating factors, contributing elements, and challenges in elucidating trends, as well as implications for clinicians who provide pretravel advice and those who care for ill returning travelers.

Travel and venous thrombosis: a systematic review

In the past decade, numerous publications on the association between venous thrombosis (VT) and travel have been published. Relative and absolute risks of VT after travel, and particularly after travel by air, have been studied in case-control and observational follow-up studies, whereas the effect of prophylaxis has been studied through intervention trials of asymptomatic clots. The mechanism responsible for the association between travel and VT was addressed in pathophysiologic studies. Here, we systematically reviewed the epidemiologic and pathophysiologic studies about the association between travel and VT. We conclude that long-distance travel increases the risk of VT approximately two to fourfold. The absolute risk of a symptomatic event within 4 weeks of flights longer than 4 h is 1/4600 flights. The risk of severe pulmonary embolism (PE) occurring immediately after air travel increases with duration of travel, up to 4.8 per million in flights longer than 12 h. The mechanism responsible for the increased risk of VT after (air) travel has insufficiently been studied to draw solid conclusions, but one controlled-study showed evidence for an additional mechanism to immobilization that could lead to coagulation activation after air travel.

Air travel and venous thromboembolism: a systematic review

CONTEXT

Despite multiple attempts to document and quantify the danger of venous thromboembolism (VTE) following prolonged travel, there is still uncertainty about the magnitude of risk and what can be done to lower it.

OBJECTIVES

To review the methodologic strength of the literature, estimate the risk of travel-related VTE, evaluate the efficacy of preventive treatments, and develop evidence-based recommendations for practice.

DATA SOURCES

Studies identified from MEDLINE from 1966 through December 2005, supplemented by a review of the Cochrane Central Registry of Controlled Trials, the Database of Abstracts of Reviews of Effects, and relevant bibliographies.

STUDY SELECTION

We included all clinical studies that either reported primary data concerning travel as a risk factor for VTE or tested preventive measures for travel-related VTE.

DATA EXTRACTION AND ANALYSIS

Two reviewers reviewed each study independently to assess inclusion criteria, classify research design, and rate methodologic features. The effect of methodologic differences, VTE risk, and travel duration on VTE rate was evaluated using a logistic regression model.

DATA SYNTHESIS

Twenty-four published reports, totaling 25 studies, met inclusion criteria (6 case-control studies, 10 cohort studies, and 9 randomized controlled trials). Method of screening for VTE [screening ultrasound compared to usual clinical care, odds ratio (OR) 390], outcome measure [all VTE compared to pulmonary embolism (PE) only, OR 21], duration of travel (<6 hours compared to 6-8 hours, OR 0.011), and clinical risk ("higher" risk travelers compared to "lower," OR 3.6) were significantly related to VTE rate. Clinical VTE after prolonged travel is rare [27 PE per million flights diagnosed through usual clinical care, 0.05% symptomatic deep venous thrombosis (DVT) diagnosed through screening ultrasounds], but asymptomatic thrombi of uncertain clinical significance are more common. Graduated compression stockings prevented travel-related VTE (P < 0.05 in 4 of 6 studies), aspirin did not, and low-molecular-weight heparin (LMWH) showed a trend toward efficacy in one study.

CONCLUSIONS

All travelers, regardless of VTE risk, should avoid dehydration and frequently exercise leg muscles. Travelers on a flight of less than 6 hours and those with no known risk factors for VTE, regardless of the duration of the flight, do not need DVT prophylaxis. Travelers with 1 or more risk factors for VTE should consider graduated compression stockings and/or LMWH for flights longer than 6 hours.

Renewal of surgical quality and safety initiatives: a multispecialty challenge

The quality and safety movement in surgical specialty practice is gaining momentum. On the basis of risk-adjusted outcomes of coronary artery surgery and the improved risk assessment in the Veterans Affairs system, a growing array of surgical specialists has focused on recognition of legitimate risk factors, identification of performance measures that are valid surrogates for better practices, and refinement of risk-adjusted outcomes. Recognition of educational needs, personal practice patterns, and systems deficiencies now permits a broad-based application of long-standing primarily medical issues to elective surgical procedures in an organized and Integrated fashion. Approximately 85,000 patients per day undergo elective operations in the United States. A platform based on physician involvement and leadership has been tested in the Surgical Care Improvement Project, funded by a subcontract from the Centers for Medicare and Medicaid Services. This effort has defined factors worthy of further verification and provides a framework for an ethical and valid pay-for-performance scheme.