Traveller’s Thrombosis

An MRINZ-led research programme has quantified the risk of traveller’s thrombosis, encompassing both deep vein thrombosis (DVT) and pulmonary embolism (PE) associated with long distance air travel.

In the largest study of its kind, the MRINZ has shown that the risk of a DVT or PE in adults following long distance travel, such as flying from NZ to the UK and back, is about 1 in 100. This has led to a series of studies identifying that prolonged seated immobility at work or with leisure activities, such as computer gaming, is a significant yet poorly recognised risk factor for DVT and PE. Both the total duration of sitting in a 24-hour period, and the time spent sitting at one time, were identified as important determinants of risk.

The term ‘seated immobility thrombosis’ (SIT) was proposed to describe venous thromboembolism occurring after prolonged seated immobility in any circumstance, ranging from air, road and train travel, to prolonged seating at work and with leisure activities. Together, SIT in its various forms has been identified as a risk factor in over one third of DVT and PE cases in New Zealand.

In a programme of dedicated research, a small novel footstool device was designed, and its use shown to markedly increase venous blood flow in the legs. It has now been commercialised as a device to reduce blood clot risk in people who sit for long periods at work, or during other sedentary activities and with long distance air travel.

Fever is a key sign of severe illness and yet it is poorly understood and its treatment has not been guided by high quality evidence. The MRINZ has conducted world-leading research to evaluate fever management in the ICU. Their research showed that paracetamol is safe for treating patients in intensive care and may even help them recover and leave hospital more quickly. These findings have informed clinical practice around the world.

Treatment of Fever

As an over-the-counter medication, and having been in clinical use for over a century, paracetamol is the standard first-line treatment for fever and acute pain. However, its use pre-dates the era of evidence-based medicine and there have been opposing theories as to the benefits and risks of its use in treating fever. One argument is that fever places additional physiological stress on patients who are already ill, and removing this source of increased metabolic demand would allow the body to allocate additional resources to fighting the infection. Conversely, other studies have observed that fever may enhance immune cell function, inhibit the growth and spread of an infecting pathogen and improve the activity of antimicrobials. These conflicting arguments demonstrate a lack of conclusive evidence surrounding the effect of treating fever with paracetamol, with no high-level proof that paracetamol treatment of fever due to probable infection is beneficial, ineffective, or harmful.

Remarkably, although paracetamol is widely administrated to ICU patients with fever and infection, and despite the strong rationale that fever might be important to fight off infection, the MRINZ-led HEAT trial was the first to investigate the safety and efficacy of administering paracetamol to critically ill patients admitted to ICU with fever due to infection.

The HEAT trial shows that the treatment of fever with paracetamol is safe and does not make health outcomes worse, although it has minimal effect on either temperature or symptoms and does not reduce mortality risk. These findings have contributed to the evidence base for the far-reaching use of paracetamol across a range of conditions and illness severity.

We’ve been putting tubes into people with collapsed lungs since the beginning of the 20th century, thinking we were doing our best to treat this condition. Now, this study makes it clear that conservative treatment rather than an invasive interventional approach is better. Patients suffering a pneumothorax can be sent home to recover and get back to work and their daily lives sooner, avoiding all the complications that go along with inserting a chest tube such as infection, trauma, bleeding and recurrence.