Health occupations

Howard Roby Specialist in Anaesthesia and Intensive Care; and Medical Director, Customer Care Medical Assistance, Private Bag 913, North Sydney, NSW 2059. macrobyATozemail.com.au To the Editor: As the medical director of Customer Care Medical Assistance, which manages the travel insurance policies of most travelling Australians, I wish to reassure readers that none of the experiences chronicled by Grace and Penny1 related to our company. I have previously described the activities of Customer Care in the Journal.2 I would welcome any enquiries from colleagues about the way our company functions. I note that there was no declaration by Grace and Penny of their competing interests.

Howard Roby

John Fraser,* Christian Alexander,† Berniece Simpkins‡ * Director, † Senior Research Fellow, ‡ Health Career Promotion Project Officer, New England Area Rural Training Unit, New England Area Health Service, PO Box 83, Tamworth, NSW 2340 jdfraserATdoh.health.nsw.gov.au To the Editor: We read with interest the recent article concerning Australian medical workforce issues.1 Brooks et al comment on feminisation, lifestyle changes, increased community demand and globalisation as major issues for the future medical workforce. Here, we present data from recent rural high school health career promotion activities, describing student interest in health careers. These data further support this trend in feminisation. Promotion of health careers in high schools is a core long-term rural workforce strategy in Australia.2 It is justified, as rural origin is an important predictor of medical graduates pursuing a rural health career.3 The New England Area Rural Training Unit (NEARTU) promotes rural health careers to school students, undergraduates and postgraduates in north-west New South Wales. Multidisciplinary regional health career expos were offered to all high school students in Years 9 to 12 from 2000 onwards in the regional centres of Armidale, Tamworth and Moree. Medical, nursing and allied health professionals and undergraduates (of both sexes) staffed the expos. Inquiries were recorded by sex, year at school and health career. Students could enquire about multiple careers. In 2000, 453 high school students (394 female; 59 male) expressed an interest in health careers at expos. The Box displays that, for both female and male Year 9 to Year 11 students, interest in a nursing career far exceeds interest in either allied health or medicine, and, for Year 12 students, an interest in allied health far exceeds interest in either nursing or medicine. Enquiries were more frequent from females than from males, ranging from just over four times (medicine) to eight times more frequent (nursing). In 2000, 60% of these students’ enquiries (270 enquiries) referred to nursing, 33% (151 enquiries) referred to allied health and 7% (32 enquiries) referred to medicine. Compared with the Australian Bureau of Statistics 2001 data, which showed a 50.4 to 49.6 ratio of females to males in the region’s high schools, our increased interest by females is statistically significant (P < 0.01). In other careers projects by NEARTU in 2000–2002 (eg, work experience placements, and health career promotion at local agricultural field days), similar sex differences were observed (female-to-male ratio range, 10:1 to 3.5:1). Increased interest by female high school students is consistent with other reports of high school students’ health career preferences in the United States. 4,5 Registering interest is only the first step in considering a health career. The higher proportion of females expressing this interest in rural high schools is important for rural workforce planning. Interest in health careers by high school students in 2000

John Fraser · Christian Alexander · Berniece Simpkins

Clinical recordA 56-year-old woman presented to her general practitioner a fortnight after a trip to Bali. She had a 2-week history of profuse loose brown stools, lethargy, weakness, nausea and some dyspeptic symptoms. The diarrhoea had initially settled with loperamide, but then recurred. A faecal specimen was collected for microscopy, culture and testing for enteric viruses, all of which gave negative results. Routine blood tests showed mild iron deficiency with no anaemia. Serum levels of vitamin B12 and folate were in the reference ranges. Serological testing for Toxoplasma and Cytomegalovirus showed no evidence of recent infection. An initial course of metronidazole for presumed Giardia infection was unhelpful, and she was referred for further gastroenterological evaluation. At the time of review by the gastroenterologist, she had had persistent diarrhoea for nearly 4 weeks. Thyroid, respiratory, abdominal and cardiovascular examination gave unremarkable results. A faecal enzyme-linked immunoassay analysis for Giardia antigens gave negative results. Gastroscopy showed mild diffuse gastritis, and a rapid urease test for Helicobacter pylori was negative. The duodenum appeared normal, and small-bowel biopsy specimens were sent for disaccharidase testing and histopathological examination. No abnormalities were seen on colonoscopy. Faecal fluid was collected and sent in formalin for saline–acid fixation faecal testing. Examination of small-bowel biopsy specimens showed moderate villous blunting with increased intraepithelial and lamina propria lymphocytes and no evidence of dysplasia or malignancy, no granulomas or parasites. The report concluded that this appearance was very suggestive of coeliac disease. (Figure 1). However, examination of the faecal specimen in saline–acid fixative revealed oocytes of Cyclospora cayetanensis (Figure 2). 1: Small-bowel biopsy specimens taken before and after treatment with trimethoprim–sulfamethoxazole, showing moderate villous blunting before treatment (left) and normal architecture after treatment (right) (original magnification, x 50). 2: Oocysts of Cyclospora cayetanensis (left) and Cryptosporidium parvum (right), showing size difference (original magnification, x 1000). A diagnosis was made of small intestinal villous atrophy secondary to C. cayetanensis infection. The patient was treated with trimethoprim–sulfamethoxazole (800 mg/160 mg twice daily for 5 days). Her symptoms resolved within days. Serological tests and a repeat small-bowel biopsy were undertaken to exclude latent coeliac disease. Serological testing was negative for antigliadin and antiendomysial antibodies, and there was no evidence of residual villous atrophy in the biopsy specimen (Figure 1). The patient remained well on follow-up after completing the course of antibiotics. This case of protracted diarrhoea in an Australian traveller initially appeared consistent with coeliac disease. Further analysis revealed infection with Cyclospora cayetanensis, which was successfully treated with antibiotics. The increasing number of documented outbreaks of Cyclospora infection,1 and the need for special preparation of stool samples for their detection,2 highlight the importance of a high degree of suspicion in cases of traveller’s diarrhoea. C. cayetanensis is a protozoan which was first recognised as a human intestinal parasite in the early 1990s.3 In 1994, Butcher et al described the first case in an Australian traveller of explosive diarrhoea caused by a large acid-fast spherical organism that had only recently been classified as a member of the genus Cyclospora.4 Since then, reports of outbreaks of Cyclospora infection have increased,1 presumably due to greater awareness of this parasite. Outbreaks have been reported from many parts of the world, including North, Central and South America, Europe, South East Asia, India, South Africa, and the Caribbean Islands.5,6 The mode of transmission is thought to be faecal–oral, or via ingestion of contaminated water. The mechanism by which the protozoan causes villous atrophy is not well understood, but organisms have been found at the site of inflammatory changes. Like Cryptosporidium spp. (which are morphologically similar [Figure 2]), Cyclospora spp. cause nausea, profuse diarrhoea and weight loss, as well as profound fatigue. Abdominal pain and bloating can manifest as “indigestion” or “heartburn”. If untreated, symptoms last for 6 weeks to 3 months (longer in the immunocompromised), and can be mistaken for irritable-bowel syndrome. The treatment of choice is trimethoprim–sulfamethoxazole, with ongoing prophylaxis for patients with AIDS.7 Clinicians need to be aware that the histopathological appearance of the small intestine in C. cayetanensis infection is similar to that in coeliac disease. Other causes of small-intestine villous atrophy include viral enteritis, giardiasis, and cows’ milk allergy. Hence, diagnosis of coeliac disease should not be based purely on the finding of villous atrophy. Investigations that we used to test the diagnosis in this patient included a highly specific immunoassay for giardia antigens, as well as testing for antiendomysial and antigliadin antibodies to disprove coeliac disease definitively. However, the clinical history (particularly onset and duration of illness) needs to be considered before requesting these tests. In the setting of recent travel or a community outbreak, a high index of suspicion for infectious causes of villous blunting is warranted. Despite the increasing knowledge about the genus Cyclospora, many infections are missed, as the parasite can be difficult to detect in human faecal samples. Clinicians need to be aware that acid-fast staining is required, and that this requires preservation of the faecal specimen in formalin.3 It is also important to realise that Cyclospora oocysts are usually shed in low numbers, even when the patient is very ill. In addition, faecal specimens sent to pathology laboratories for examination for ova and parasites are commonly not examined for Cyclospora spp. Hence, Cyclospora testing must be specifically requested.2 Finally, laboratory investigators need to be aware that Cyclospora cysts are morphologically similar to cysts of Cryptosporidium parvum. The most obvious difference is size, as Cyclospora cysts are larger (8–10 μm) than Cryptosporidium cysts (4–6 μm) (Figure 2). It is important to differentiate the two, as Cyclospora infection can be treated with antibiotic therapy, whereas management of Cryptosporidium infection is largely supportive.5 Dialogue between the clinician and pathologist can help to avoid confounding diagnoses. Newer techniques, such as polymerase chain reaction (PCR) testing for parasite DNA, are currently being developed, but are expensive and may not be available in a routine laboratory. Lessons from practice Cyclospora cayetanensis was relatively recently recognised as an intestinal parasite that causes protracted diarrhoea. Beware of histological and clinical overlap with other conditions, including coeliac disease, cryptosporidiosis and irritable-bowel syndrome. Cyclospora organisms can be difficult to detect: faecal specimens need to be transported in a saline–acid fixative, and examination for Cyclospora needs to be specifically requested. Treatment is a 7–10-day course of trimethoprim–sulfamethoxazole.

Vidyut Pinge-Suttor BSc(Med), MB BS · Chris Douglas FRCPA(App) · Antony Wettstein FRACP

Travel insurers and medical evacuation companies have a responsibility to provide an efficient high-quality service to their clients. These companies often deliver a standard far short of best practice and far short of their promotional brochures. Their services are overdue for governmental review and a lifting of standards. Travellers must be given realistic advice about the risks of foreign travel and that healthcare resources at their destination may be very limited. Travellers must check with their insurer that the policy they buy truly meets their needs. Some people should not travel overseas.

Robert F Grace FANZCA, FRACP · Darren Penny DipHlthSc

Healthcare workforce shortfalls require a rethinking of models for delivering care to people with chronic disease. Chronic disease needs to be managed by a multiskilled team of healthcare professionals with specialist input. Education at undergraduate, graduate and postgraduate levels needs to prepare healthcare professionals for this new paradigm. Some tasks currently seen only as part of a doctor’s purview could be performed by other trained professionals to allow doctors to concentrate on more appropriate activities. We need to explore new collaborations to deliver multidisciplinary healthcare for chronic disease and evaluate these for patient outcomes and cost effectiveness.

Peter M Brooks FRACP, FAFRM, FAFPHM

To the Editor: Figures from the Australian Bureau of Statistics show that Australians make about 3.3 million overseas departures each year.1 Few data are published on the extent to which Australian travellers seek pre-travel health advice, what vaccinations they receive, and what risks they are exposed to during travel. A series of surveys of travellers examining these questions has been conducted under the auspices of the Travel Health Advisory Group, a coalition of Australian travel and medical organisations. Surveys were conducted in 1996, 1997, 2000, 2001 and 2002. On each occasion, a market research company telephoned people from mainland capitals using numbers randomly selected from the telephone directory. This process continued until 500 people aged 18 or over who had travelled overseas in the previous two years had been interviewed. In the 2002 survey, about 10 000 calls were made to complete the interviews. The questions on vaccinations focused on hepatitis A and B, two of the most common vaccine-preventable diseases associated with travel.2 Results from the 2002 survey are shown in the Box. A minority of people (31%) reported seeing a doctor or travel clinic for pre-travel health advice. Of those who saw a doctor or travel clinic, 31% did so two weeks or less before departure. Over the series of surveys, there has been an increase in travel to destinations with high- or intermediate-risk for hepatitis A infection, from 40% of travellers in 1996 to 58% in 2002. Despite this increase, only a minority of travellers could recall ever being vaccinated for this illness. Travellers were informed about how they might be exposed to hepatitis A and B and asked if they believed that they could have been at risk during their most recent overseas trip. Substantial numbers recalled a risk (34% and 16% for hepatitis A and B, respectively) and some of these could not recall being vaccinated (18% and 7%, respectively) (Box). These surveys have methodological limitations, including lack of information on the consent rate and potential recall bias. However, the results suggest that substantial numbers of travellers do not seek pre-travel health advice and are at risk of vaccine-preventable diseases during travel. Not only does this have implications for individual travellers, it also creates public health risks, as travellers can introduce hepatitis A and B into their home communities. These results suggest more public education is needed about the importance of pre-travel health advice and appropriate vaccination. Results of 2002 survey of Australian travellers overseas Variable No. of travellers (n = 500) Age (years) 18–29 156 (31%) 30–49 188 (38%) ≥ 50 153 (31%) Not stated 3 (0.6%) Male sex 205 (41%) Hepatitis A risk in country visited* High 226 (45%) Intermediate 62 (12%) Low 212 (42%) Sought pre-travel health advice from doctor or travel clinic Doctor 135 (27%) Travel clinic 20 (4%) No professional advice 345 (69%) Believed could have been at risk of hepatitis on most recent trip Hepatitis A 168 (34%) Hepatitis B 79 (16%) Vaccinated against hepatitis Hepatitis A 195 (39%) Hepatitis B 197 (39%) Believed at risk of hepatitis on most recent trip and not vaccinated or unsure Hepatitis A 91 (18%) Hepatitis B 36 (7%) Hepatitis A risk in country visited* among those not vaccinated for hepatitis A or unsure High 123 (25%) Intermediate 40 (8%) Low 142 (28%) * As defined by the United States Centers for Disease Control and Prevention, 2000.3 Destinations for the cohort of 500 were Asia (45%), northern Europe (28%), southern Europe (14%), North America (15%), Oceania (14%), eastern Europe (3%), Africa (3%), Middle East (2%), South America (1%) and Central America (1%), with some having more than one destination.

Nicholas A Zwar

In response to difficulties meeting the demand for hospital services ("access block") at Royal Melbourne Hospital, a major metropolitan tertiary referral hospital, an audit of patient needs revealed a shortage of aged-care beds and a need for post-acute care. A multidisciplinary Care Coordination Team (CCT) was formed at the end of July 2000 to ensure that emergency department patients were provided with services that would facilitate their return to, or maintenance in, the community. The target population included the frail elderly, those living alone, the homeless, frequent emergency department attenders, and those with complex medical or drug and alcohol problems. As part of routine emergency department care, a risk screen was implemented to determine referral to the CCT. In the first 12 months, the CCT saw 2532 patients (5.8% of all emergency department attendances). Nearly half of these patients were discharged home with referrals to community service providers. The rate of hospital admission from the emergency department fell significantly compared with the 12-month period before implementation of the CCT (13 420 patients, 30.9% [95% CI, 30.5–31.3] v 14 217 patients, 32.6% [95% CI, 32.2–33.0]; P < 0.001). Surveys of staff, patients and carers, as well as community service providers, showed a high level of satisfaction with the CCT.

Joanne E Moss MNurs(Melb), BNurs · Liza M Houghton BAppSci(Nurs), GradDipNurseEd · Carolyn L Flower BOccThy, Occupational Therapist, Emergency Department Care Coordination Team · Danielle L Moss BA, BSW · David A Nielsen BAppSci(Nurs), GradDipGeronNurs · David McD Taylor MD, FACEM

Stroke is the third highest cause of death and the leading cause of chronic disability in adults in Australia. Studies show clear advantages of treatment of patients in the acute phase of stroke in a dedicated stroke unit. Rehabilitation after stroke is a continuum, starting within days of stroke onset and ending only when it no longer produces any positive effect. More than half the 75% of patients who survive the first month after a stroke will require specialised rehabilitation. Effective rehabilitation relies on a coordinated, multidisciplinary team approach. Regular team meetings, as well as meetings with the patient, his or her family and carers, are essential. Improvements in function after stroke are the result of recovery within the ischaemic penumbra, resolution of cerebral oedema, neuroplasticity, and compensatory strategies learnt by the patient. Evidence supporting rehabilitation programs is based on evaluation of the multidisciplinary approach, or on the effect of a particular discipline (eg, speech therapy), rather than on individual components of treatment. When the patient is discharged from a formal rehabilitation program, the general practitioner's role becomes paramount. GPs can help patients deal with the consequences of stroke, such as depression, and any comorbidities. GPs may also provide counselling on issues ranging from interpersonal and sexual relationships, through ability to drive again, and vocational and recreational activities.

Michael R P Pollack FAFRM, MMedSci(ClinEpi) · Peter B Disler PhD, FAFRM, FRACP

This issue of the Journal launches a series of articles on rehabilitation medicine aimed at general practitioners and other doctors who have not specialised in this field. We, and our co-authors, hope to demonstrate that rehabilitation is a dynamic and critical component of the therapeutic continuum, and one that is essential if patients are to regain good quality of life after serious illness or injury. Rehabilitation has been defined by the World Health Organization (WHO) as "a process aimed at enabling persons with disabilities to reach and maintain their optimal . . . functional levels . . . ."1 However, this definition will require some revision, as, in May 2001, WHO adopted the International Classification of Functioning, Disability and Health.2 The new classification has modified the concept of disability to recognise that personal and environmental factors directly influence the experience of people with disability, and the term "handicap" has been dropped because of its negative connotations. With the new terminology, rehabilitation is seen as a coordinated process that enhances "activity" and "participation" (Box 1). Rehabilitation medicine was recognised as a principal specialty in Australia in 1978 and as a Faculty of the Royal Australasian College of Physicians in 1991. The early development of the specialty was largely in response to the need to manage disabilities resulting from wars, and occupational and road trauma. There has traditionally been a focus on physical medicine, but increasingly rehabilitation is acknowledging the patient's social context.3 Topics for this MJA Practice Essentials – Rehabilitation Medicine series have been selected partly on the basis of the prevalence of the impairment or condition, and partly because of the impact they have on individuals. Stroke, musculoskeletal injuries, brain injury and rehabilitation in the context of older people will be examined, beginning with "Rehabilitation and older people" on page 387. There are many reasons why rehabilitation is of such importance in the new millennium. Firstly, populations are ageing rapidly, and the incidence and prevalence of common disabling conditions (such as stroke and fractured femur) increase markedly in older people (Box 2).4 Secondly, curative and perioperative medicine has greatly improved in recent years. Frail elderly people undergo major surgery, and trauma victims who in previous years would have died now survive. However, this may be at the cost of significant impairment and disability. Finally, the past few decades have seen the development of new chronically disabling conditions such as AIDS. These changes have had an enormous impact on the medical workforce, as a substantial cadre of highly qualified, committed medical specialists is needed to work in the rehabilitation field (the number of such specialists currently falls far short of agreed standards5), while other doctors need to be educated to refer appropriately and manage disability within their field of practice. The rehabilitation medicine physician is part of an interdisciplinary team the members of which have complementary roles. Allied health professionals and nurses are essential members of this team, whose input is determined by the patient's specific rehabilitation goals. Where does the general practitioner fit into these highly specialised areas? The GP's role in rehabilitation is primary care of people with disability, tertiary prevention of disability, coordination of maintenance care, and identification of situations requiring involvement of specialist rehabilitation services. There are also substantial opportunities for GPs to assist in the primary prevention of disability related to musculoskeletal injuries, particularly those occurring in the context of compensable road trauma or work injury. Additionally, patients will benefit if GPs have direct interaction with specialised rehabilitation services operating in inpatient or ambulatory care settings or in patients' homes. Effective interaction may be encouraged by the use of case conferencing and care planning, using the structure of the Enhanced Primary Care initiative.6 Finally, it is no longer sufficient to adopt a particular therapeutic approach because it "feels right"; an evidence base is just as important in rehabilitation medicine as it is in any other specialised field. Despite the relatively low use of expensive technology or drugs in rehabilitation, the high staff-to-patient ratio makes it an expensive commodity, and if we are to persuade private and public purchasers to commit to rehabilitation we need to provide data to support its value.7 Although rehabilitation is a relatively new research field, the last few years have seen a great increase in high quality publications, including systematic reviews from the Cochrane Collaboration,8,9 and clinical practice guidelines.10 Each article in this MJA series will review the research that backs up the aspects discussed, or point to the need for research where only consensus recommendations are available. Evidence-based recommendations will be graded according to the system of the National Health and Medical Research Council (Box 3).11 The rehabilitation paradigm differs from the curative one in many ways. It is an individualised, patient-oriented activity focused on disability rather than disease. Rehabilitation moves from impairment towards helping the patient find "ability" in the presence of obvious disability. 1: Definition of terms from the International Classification of Functioning, Disability and Health (ICF)2 In the context of health: Impairments are problems in body function or structure such as significant deviation or loss. Activity is the execution of a task or action by an individual. Participation is the involvement in a life situation. Activity limitations are difficulties an individual may have executing activities. Participation restrictions are problems an individual may experience in involvement in life situations. Environmental factors make up the physical, social and attitudinal environment in which people live and conduct their lives. 2: Increase in prevalence of disability in the Australian population with age (data for 1998) Reproduced from Australian Bureau of Statistics: Disability rates by age and sex, 1998.4 In this survey, disability was defined as a limitation, restriction or impairment which lasted, or was likely to last, for at least 6 months, and restrict everyday activities. 3: Level-of-evidence codes Evidence-based recommendations in the Rehabilitation series are graded according to the National Health and Medical Research Council system11 for assessing the level of evidence. E1 Level I: Evidence obtained from a systematic review of all relevant randomised controlled trials. E2 Level II: Evidence obtained from at least one properly designed randomised controlled trial. E31 Level III-1: Evidence obtained from well-designed pseudo-randomised controlled trials (alternate allocation or some other method). E32 Level III-2: Evidence obtained from comparative studies with concurrent controls and allocation not randomised (cohort studies), case–control studies, or interrupted time series with a parallel control group. E33 Level III-3: Evidence obtained from comparative studies with historical control, two or more single-arm studies, or interrupted time series without a parallel control group. E4 Level IV: Evidence obtained from case-series, either post-test, or pre-test and post-test.

Peter B Disler · Ian D Cameron · Stephen F Wilson

The usual presentation of a returned traveller is with a particular syndrome — fever, respiratory infection, diarrhoea, eosinophilia, or skin or soft tissue infection — or for screening for asymptomatic infection. Fever in a returned traveller requires prompt investigation to prevent deaths from malaria; diagnosis of malaria may require up to three blood films over 36–48 hours. Diarrhoea is the most common health problem in travellers and is caused predominantly by bacteria; persistent diarrhoea is less likely to have an infectious cause, but its prognosis is usually good. While most travel-related infections present within six months of return, some important chronic infections may present months or years later (eg, strongyloidiasis, schistosomiasis). Travellers who have been bitten by an animal require evaluation for rabies prophylaxis.

Series Editors:

International travel and health. Geneva: World Health Organisation, 2002 (viii + 193 pp). ISBN 92 4 158027 5. The World Health Organization has a measure of credibility when it comes to producing a book called International travel and health. Although this book is updated annually, in some years the most significant difference has seemed to be the change of colour to the stripe on the cover. The 2002 edition, though, is different! The book has almost doubled in size, the cover has changed from the traditional yellow to a modern teal and, most significantly, there has been a change in the content. The claim on the cover of “abundant new material” is true. The list of acknowledgements reads like a “who’s who” of travel medicine and their input has made the book up to date and value for money. A diverse range of travel medicine topics are dealt with, from the traditional to the more unusual. Vaccinations, malaria, medical kits, altitude, deep vein thrombosis, jetlag, flight phobia, stings, worms, drownings, traffic accidents, muggings, travelling when pregnant, or with pre-existing medical conditions, and even risks from aircraft disinfection, ozone and cosmic radiation, are all dealt with. There is a particularly useful reference section summarising aspects of the infectious diseases that pose risks to travellers. The book is organised logically with an extensive table of contents, index, excellent headings, and plenty of tables. The 12 maps in the centre give an excellent overview of the extent of various diseases in 2001 (eg, Japanese encephalitis, dengue, yellow fever, malaria, hepatitis A, B and C, rabies. The popular “Country List” remains — it outlines the current vaccination requirements and malaria situation for each country. This has limited value given the static nature of the publication, but takes up only 26 pages in a publication of 180 pages, so it does not detract too much from its general usefulness. This 2002 edition is a great leap forward! Deborah J MillsMedical Director Travel Medicine and Vaccination Clinic, Brisbane, QLD

Deborah J Mills

To the Editor: Lamberth stated in his case report that Antarctic tourist ships should be equipped to provide life support, as well as better screening and education of Antarctic tourists.1 I recently travelled to both the Arctic and Antarctic as a medical officer on small ships, caring for seven passengers injured in a helicopter crash in the remote Russian Arctic and a 12-year-old with diabetic ketoacidosis in the Drake Passage, as well as numerous people with minor ailments. To compare these ships with large tropical cruise liners is unrealistic. Ships' medical supplies are selected with an appreciation of the casemix. A study of 16 Antarctic trips in 1997 and 1998 found that most problems were respiratory tract complaints, acute soft tissue injuries and complaints, sea sickness and dermatological problems.2 Few major incidents have been reported, and equipment for advanced life support is tailored to this. Paralysing agents and ventilators are not supplied. A single doctor with no nursing staff cannot safely care for a ventilated patient for 72 hours, as suggested by Lamberth, and the additional staff needed for this would be a huge additional expense for a very rare occurrence. While some ingenuity and adaptability may be required, the equipment supplied is adequate for the vast majority of events. Safety and preventive medicine are very much part of the ship's doctor's role. Most doctors give a brief lecture as part of the initial briefing of passengers. Seasickness, appropriate medication and safety on the ship are usually part of this. The passengers are predominantly elderly and, in my experience, many are fulfilling a long-held ambition to travel to the polar regions. Reputable companies require a fitness-to-travel assessment from passengers' general practitioners before the trip is confirmed. This assessment is tailored to potential problems in remote regions. I believe that excluding people from the wonders of polar travel on the basis of age or previous coronary artery disease would be a terrible shame, while accepting that there will always be a risk in travelling to remote locations. Having shared in the 90th birthday celebration of a woman with chronic obstructive pulmonary disease in the Arctic, I hope that I will still be able to enjoy such experiences at that age.

Eve R Merfield FACEM

To the Editor: Lamberth raised some worthwhile issues about small-ship adventure tourism to Antarctica in his recent case report describing the death of an 82-year-old tourist.1 This occurred in 1999, the season I started as medical director for the leading polar adventure tour company that chartered the vessel involved. I have some comments and an update. The former Soviet oceanographic research vessel was converted in the 1990s to carry 78 passengers. She had a two-bed infirmary and a procedure room with Russian and German medical supplies for passengers and crew, and carried a German- and English-speaking Russian doctor experienced with passenger ship medicine. The tour operator provided additional medical supplies and an emergency physician. Ventilatory support could have been provided, although not to the standard of a contemporary Australian intensive care unit. Polar adventure operations are very different from "tropical" cruise lines, which generally operate their own ships from home ports and cater for up to 3000 passengers with very different expectations.2 Operators require that prospective passengers submit a medical information form and a declaration from their personal physician that they are fit for the journey. The 82-year-old who died was a retired physician who did not declare the extent of his limitations, and who acted as his own medical advisor. His is the only death I am aware of after seven years' involvement in the industry. The medical declaration form has been modified and now addresses the risk factors identified by Lamberth. Prospective clients with questionable health are referred to the medical director. However, operators cannot verify declarations of good health, and physicians have been known to collude with passengers to avoid risk of rejection. Furthermore, "ageism" is as unacceptable as sexism and racism. I was present on the first passenger-circumnavigation of Antarctica in the company of several octogenarians and a 90-year-old, and on the first circumnavigation of the Arctic Ocean, with other octogenarians and a 92-year-old. Short trips to the Antarctic Peninsula are very different from scientific expeditions; Lamberth's suggestion that advising doctors should consider scientific expedition criteria is inappropriate. The International Association of Antarctic Tour Operators (<www.iaato.org>) is a voluntary association of competing adventure eco-tour operators whose purpose is to self-regulate the industry and to develop good standards. Standards for provision of medical supplies and capabilities are under development by this association.

Chris H Curry

In reply: I welcome Curry and Merfield's interest and comments. The patient described in my case report1 was not, as Curry states, "a retired physician". Nor did he provide his own health assessment, but had his assessment form filled out by another physician. Unfortunately, this form, along with those of 60 other passengers, was not made available to any doctor before embarkation. Curry confirms that many older passengers are travelling to Antarctica.2 Merfield's experiences attest to the potential for serious (including multiple casualty) incidents in this remote location. I agree that ageism per se is unacceptable. Rather, the issue is the provision of adequate facilities to deal with potential problems or, alternatively, warning as to the hazards. Advertising for Antarctic cruises emphasises the medical facilities provided. The public may not realise that a doctor with minimal equipment cannot deliver the same care available in a First World hospital. Curry's assertion that ventilation could have been provided illustrates this. Ventilation is more than placement of an endotracheal tube. It is ludicrous to suggest that, without oxygen, paralysing drugs, positive end-expiratory pressure or means to suction the copious thick secretions, hand-bagging for 36 hours while crossing the heavy seas of the Drake Passage might have altered the tragic outcome for this patient. I recommend a book by Levinson, a seasoned polar physician, and Ger on health aspects of polar tourism.3 They have collated the findings of a conference held on this topic at Cambridge in the United Kingdom in 1995. The book addresses what Levinson describes as "the often inadequate medical care which exists in these regions". He notes "major concerns . . . expressed by travel experts, the American Medical Association, the American College of Emergency Physicians, and other professional organisations."3 The survey by Curry and Johnston found that illnesses among their company's Antarctic tourists in 1997 and 1998 included cardiac arrest, acute myocardial infarction, severe pneumonia, diabetic ketoacidosis due to seasickness, haematemesis, anaphylaxis, ruptured ectopic pregnancy and acute appendicitis. The fact that polar trips are short does not seem to protect against potentially lethal diseases. Given the stress of this travel and the nature of the population involved, maybe the contrary applies.

Paul G Lamberth FACEM

Objective: To summarise recent evidence from case reports (published January 1995 – September 2001) of adverse events after cervical spine manipulation.Data sources: Five computerised literature searches (MEDLINE – Pubmed; EMBASE, the Cochrane Library, AMED [Allied and Complementary Medicine Database], and CISCOM [Centralised Information Service for Complementary Medicine]) were performed. No language restrictions were applied.Study selection: All case reports containing original data of adverse events after cervical spine manipulation were included.Data extraction: All articles were evaluated and key data extracted according to pre-defined criteria: patient's age, sex and diagnosis; type of therapist; type of treatment; nature of adverse event; method of diagnosis; and clinical outcome.Data synthesis: Thirty-one case reports (42 individual cases) were found. The patients were equally distributed between the sexes (21 male, 20 female, one unknown) and mostly middle-aged (range, 3 months to 87 years). Most were treated by chiropractors. Arterial dissection causing stroke was reported in at least 18 cases.Conclusions: Serious adverse events after cervical spine manipulation continue to be reported. As the incidence of these events is unknown, large and rigorous prospective studies of cervical spine manipulation are needed to accurately define the risks.

Edzard Ernst MD, PhD, FRCP(Edin)

To the Editor: The South Pacific Underwater Medicine Society (SPUMS) recommends that, before starting scuba-diving activities, all candidates undertake a medical assessment by a doctor trained in diving medicine. SPUMS recommends a minimum age of 14 years for all entry-level scuba activities, as does Australian Standard 4005.1. This recommendation is based on the belief that younger children do not have the emotional maturity and confidence to safely manage underwater emergencies. Such emergencies, which may include running out of air, being separated from your buddy, being caught in a strong current, and equipment malfunction, can all result in panic.2,3 A diver who panics will typically make a rapid ascent to the surface, risking life-threatening pulmonary barotrauma and decompression illness.2 Commercial scuba diving instructor agencies are introducing a number of introductory activities for children as young as eight years. SPUMS urges caution in assessing young children as fit to dive. Medical practitioners making these assessments should clearly understand the nature of the activity to be undertaken, the equipment to be used and the nature of the environment in which the training is to occur. They should also understand the nature of the certification to be awarded. The presence of at least one legal guardian during this assessment is desirable to ensure that the risks are fully understood and to ensure the desire for the child to undertake the activity is not that of the parents alone. An individual may meet the criteria laid down in a standard or understand and accept the risks of an aquatic sport. However, it is not clear that a young child is mature enough to make this informed choice.4 Clearly, some 14-year-olds also lack sufficient maturity, and an experienced diving physician will advise them to delay their open-water certification course until greater maturity is demonstrated. Alternatively, some children younger than 14 years may be completely safe in undertaking a highly structured, one-on-one, supervised scuba experience in a swimming pool. However, it should be understood that trialling scuba equipment in a swimming pool has resulted in significant morbidity. SPUMS continues to recommend a minimum age of 14 years for all entry-level scuba activities involving open-water dives, and recommends caution in assessing younger children for all other scuba experiences.

Robyn M Walker MB BS, DPHM

Crisis Death in Antarctica Antarctic tourism is flourishing, but Antarctic cruises are often more physically demanding than typical "tropical" cruises. An 82-year-old Antarctic tourist died of probable septic shock secondary to lower respiratory tract infection six days after sustaining a suspected vertebral fracture in a minor fall from an inflatable boat. This case highlights the need for Antarctic cruise ships to be equipped to provide life support and for better screening and education of prospective Antarctic tourists. Paul G Lamberth MJA 2001; 175: 583-584 Clinical record - Discussion - References - Authors' details - - More articles on Travel, aviation and underwater medicine Antarctic tourism has increased rapidly in recent years, possibly because the collapse of the Soviet Union has made available a fleet of icebreakers.1 The combination of cruise ship conditions and the hostile, remote environment portends health risks for travellers. Doctors on scientific expeditions to the Antarctic report dealing with a range of major medical problems, including acute abdomen requiring laparotomy,2 ruptured intracranial aneurysm,3 70% thermal burns,4 and intestinal haemorrhage requiring a multinational rescue operation.5 Although the health needs of workers in Antarctica have been documented, little is known of the requirements of unscreened tourists. I report the death of an Australian tourist on an Antarctic cruise. Clinical record An 82-year-old Australian man boarded a Russian ice-strengthened vessel in Ushuaia, at the southern tip of Argentina, for a two-week cruise to the Antarctic Peninsula. During traverse of the notoriously rough Drake Passage on Day 2, he took dimenhydrinate and hyoscine for motion sickness. On Day 3, he had a minor fall while disembarking from an inflatable boat, leaving him with back pain which he treated with paracetamol and dextropropoxyphene. His only complaint to the ship's doctor (myself) at the time was wheezing induced by the cold air. On Day 5, he missed breakfast and was found lying on the floor of his single cabin. He explained that he had been unable to get up after a fall 12 hours before. I examined him carefully, with the only positive findings being dry mucosae and exquisite localised midline vertebral tenderness elicited at T9. He had a past history of smoking-related chronic airflow limitation, treated with bronchodilators and corticosteroids, and osteoporosis. The working diagnosis was a crush fracture of a lower thoracic vertebra, for which I gave him further analgesia. The following afternoon, subtle disorientation was noted, progressing over four hours to stupor with hypotension, poor peripheral perfusion and tachypnoea. Examination revealed left basal crackles and right-sided wheeze. The right calf had become tender. Intravenous resuscitation with 10% hydroxy-ethyl starch increased his blood pressure to 125/65 mm Hg, and urine output to 40-50 mL/h. Ceftriaxone (1 g) and gentamicin (320 mg) were administered with dexamethasone (4 mg intravenously) in lieu of regular bronchodilator therapy. On Day 8, the stupor persisted. Lung auscultation revealed left basal crackles correlating with a region of dullness to percussion. There was profuse purulent sputum. The patient's insurer agreed to meet the expense of evacuation, but a plan to fly him from the nearby Russian base on King George Island to Punta Arenas in Chile was abandoned when the weather deteriorated. After discussion, the Russian captain's initial plan to leave the patient at the Russian base, which was apparently less well equipped than the ship's hospital, was dropped in favour of returning to Ushuaia at full speed. That evening, the patient developed bilateral ocular deviation to the right, poor peripheral perfusion and periodic respirations. Crystalloid was administered to treat poor perfusion and falling urine output. Lansoprazole, for stress-ulcer prophylaxis, and aspirin, for a probable left leg venous thrombosis, were also given. On Day 9, the patient remained febrile, with normal heart rate and blood pressure. Enteral fluids (2000 mL per day) with sucrose (80 g) and sodium chloride (4 g) were tolerated, with gastric aspirates under 20 mL and normal bowel sounds. That afternoon, his breathing became intermittent, he developed oliguria and bradycardia, and died at 1730 hours. The ship reached Ushuaia 16 hours later. No autopsy was performed, and the body was cremated in Argentina. Discussion The final diagnosis was septic shock secondary to lower respiratory tract infection. The patient may also have had a deep venous thrombosis with possible pulmonary embolism. Contributing factors were chronic airflow limitation, back pain due to a thoracic crush fracture complicating osteoporosis secondary to frequent corticosteroid use, immobilisation and dehydration. Cold air exacerbating bronchospasm probably also contributed, while impairment of balance and cognitive function by anticholinergic medications may have been a factor in the patient's falls. This case illustrates the fundamental principle of incident analysis — a number of seemingly minor factors can combine to produce a disaster that was not predicted from any one precipitant alone.6 The case also raises issues for Antarctic tourism: Medical stocking of ships: As the areas explored can be several days' journey from modern healthcare facilities, there is an argument that ships' hospitals should be able to provide life support for 72 hours. This is not the case on most Antarctic cruise ships, despite travel companies advertising medical supervision as a feature. In contrast, the major "tropical" cruise lines provide advanced medical facilities appropriate to the elderly and infirm nature of many of their clientele. Medical equipment on Antarctic cruises should include intravenous fluids for resuscitation and maintenance and, ideally, a portable ventilator and monitoring device, such as a pulse oximeter. Ships' doctors require a high level of critical care skills to undertake advanced life support at sea. Many ship's doctors now working in Antarctica are Australian emergency physicians. Furthermore, the risks of anticholinergic medications for motion sickness, especially in the elderly, need to be better appreciated. Disturbed balance, sedation and cognitive impairment are a deadly combination in an unfamiliar environment. NASA (the National Aeronautics and Space Administration) advises promethazine for microgravity motion sickness.7 It is believed that promethazine, unlike hyoscine, dimenhydrinate and other common anti-motion-sickness agents, relieves symptoms without impairing adaptation. Therefore, during prolonged exposure, promethazine can be ceased as travellers get their "sea legs". Screening and education of prospective passengers: Factors that increase risk during Antarctic travel include: Moderate to severe reactive airway disease, especially if precipitated by cold air. Caution should be advised for those with chronic airway disease with severe fixed obstruction (FEV1 < 1.0 L/s) or requiring frequent courses of corticosteroids. Decreased mobility or balance problems, because of the need to negotiate steep companionways in heavy seas.8 Conditions with potential complications that would be difficult to treat in a remote environment, such as coronary artery disease, pregnancy and insulin-dependent diabetes. Poorly controlled mental illness. Provision of information on motion sickness, cold environment risks, and hazards such as falls may help passengers look after their own health. Appropriate health and accident insurance should be mandatory. A nihilistic philosophy that requires tourists to accept their own risks does not take into account the impact of illness or injury on other passengers, who may seek legal remedy from the tour operator. Improved surveillance of passengers travelling alone: Passengers in single cabins appear to be at increased risk of adverse events. The failure to detect my patient's predicament until 12 hours had elapsed may have been a crucial factor in his death. A simple system of surveillance would be possible, with passengers on their own reporting to a nominated crew member twice daily. The increase in adventure tourism by the elderly is a significant health challenge. Tour companies should consider developing a standard to equip ships for life support. A well-prepared aeromedical evacuation plan would mitigate this responsibility. Physicians advising prospective passengers should consider the rigorous screening that scientific expeditions apply to participants, and the equipment and training they provide in preparation for medical emergencies.9 Tourists swimming in an active volcano, Deception Island, Antarctic Peninsula. References Prociv P. Health aspects of Antarctic tourism. J Travel Med 1998; 4: 210-212. Priddy RE. An "acute abdomen" in Antarctica. The problems of diagnosis and management. Med J Aust 1985; 143: 108-111. Pardoe RA. A ruptured intracranial aneurysm in Antarctica. Med J Aust 1965; 1: 344-350. Alcorn GB. My Antarctic practice. Med J Aust 1992; 157: 253-258. Poki MT, Semmens K. Intestinal haemorrhage in Antarctica: a multinational rescue operation. Med J Aust 1979; 2: 275-277. Mendick M. What went wrong? Analysis. the little things add up. Flight Safety Aust 2001; 5(4): 14. Cowings PS, Toscano WB, DeRoshia C, et al. Promethazine as a motion sickness treatment: impact on human performance and mood states. Aviat Space Environ Med 2000; 71: 1013-1022. Carter JW. Shipboard medicine on package cruises. BMJ 1972; 1: 553-556. Lugg DJ. Antarctic medicine. JAMA 2000; 283: 2082-2084. Authors' details Department of Emergency Medicine, Canberra Hospital, Canberra, ACT. Paul G Lamberth, FACEM, Emergency Physician, and Consultant, Shock Trauma Service. Reprints will not be available from the author. Correspondence: Dr P G Lamberth, Canberra Hospital, Yamba Drive, Garran, ACT 2606. palamATozemail.com.au Make a comment

Paul G Lamberth

Editorial Economy class syndrome A misnomer for a syndrome for which the evidence is, as yet, missing MJA 2001; 174: 264-265 Two unexpected and widely reported deaths from pulmonary embolism (PE) after flights between Australia and the United Kingdom — one of a 28-year-old woman arriving in London, the other a 68-year-old man after landing in Melbourne — have provoked four months of worldwide media interest in air-travel-related PE and deep-vein thrombosis (DVT). News headlines and editorials have reported on its supposed incidence, causes and prevention. Now the Federal Government has launched an enquiry into the risks of long-haul flying. And there is inevitable talk of litigation. Air travellers are rightly concerned to know the level of risk, who is likely to be affected, and what precautions they should take. Answers are, however, constrained by a serious lack of definitive information, as the evidence is limited to case series of DVT or PE discovered during or soon after air travel, and a few case-control studies with limited power and contradictory results. Air travellers are rightly concerned to know the level of risk, who is likely to be affected, and what precautions they should take. Venous thromboembolism (VTE) during or soon after prolonged flight or travel by motor car has been recorded since 19541 and was labelled "economy class syndrome" in 1988 (two of the six cases were authors of that report, and paradoxically, one of the authors with DVT had travelled in business class).2 Case series have come from the Paris airports (Orly and Roissy, where the airport emergency medical service diagnosed PE in 70 incoming passengers during the 24 years to 19983), Heathrow Airport (where 11 of 61 inflight deaths reported to the coroner between 1979 and 1982 were caused by PE4), the island of Martinique (40 cases of flight-related VTE in six years5) and Réunion island (six cases in one year6). Lastly, in the Hawaiian Islands, 17%-25% of patients with VTE admitted to two Honolulu hospitals had a recent history of air travel.7,8 Others have extended this association to prolonged travel by bus, car, truck or train.9 Prolonged travel in a seated position can cause venous stasis, so that an association of VTE with travel would be consistent with Virchow's classic postulate that venous stasis contributes to VTE. However, the present evidence regarding air travel as a cause of VTE is circumstantial and could be misleading. VTE is a common disorder with an annual incidence of about one per 1000 population for DVT and 0.5 per 1000 for PE.10 Its incidence is age-dependent and rises to nearly 1% per annum in the elderly.11 Given the high community prevalence of VTE and exponential growth in worldwide air travel by all age groups, the reports of flight-related VTE from isolated islands and at busy airports could therefore be mere coincidence. Clinical suspicion of VTE is notoriously misleading, so that retrospective reports might be contaminated by diagnostic bias, and recall bias could influence surveys of predisposing air travel. Prospective case-control studies seek to minimise bias and estimate risk by obtaining a history of travel from patients with VTE and also from contemporary age-matched and sex-matched controls. Two recent studies from cities with busy international airports have given opposing results. In Nice, 39 of 160 patients with VTE (24.4%) had travelled during the previous four weeks (nine by plane, 28 by motorcar and two by train), compared with 7.5% of 160 age-matched but not sex-matched controls visiting a cardiology outpatient clinic. In this study, recent travel raised the odds ratio (OR) for VTE to 4.0 (95% confidence interval, 1.9-8.4; P < 0.0001).12 By contrast, when 788 patients with a clinically suspected DVT were interviewed in Amsterdam before diagnostic testing, recent travel was no more prevalent in the 186 patients who had DVT than in the 602 where tests excluded DVT (the OR for DVT after any recent travel, prolonged travel, or air travel was 1.0; 95% CI, 0.3-1.4).13 These case-control studies do not decide the issue, as the control groups were suboptimal12,13 or the study was too small to exclude an important effect of prolonged air travel.13 In the absence of good evidence to the contrary, it is prudent to assume that air travel can provoke VTE, although the absolute risk remains uncertain and is probably quite small in most people. This conclusion derives from the Paris airports emergency medical service report.3 By relating the number of people with PE detected during or immediately after a flight to the total number of arrivals, the report derived an overall incidence of about one PE per 3 000 000 arriving travellers3 ("true" risk is likely to be somewhat higher, as about two-thirds of travel-related VTE presents after patients leave the airport14). The Paris airports report also observed an obviously greater incidence when travel times were longer than 12 hours.3 As 10 of the 11 inflight deaths from PE recorded in the Heathrow report occurred during prolonged flights,4 it is likely that travel duration will prove to be important. It is essential that this still-isolated information is verified and extended with further studies. Advice on prevention is based on assumptions about pathogenesis. In addition to the presumption of venous stasis, there are studies of aircrew or volunteers during prolonged real or simulated flights that suggest dehydration,15,16 stress and climatic change,15 and early activation of the blood-clotting system17 might also contribute. Business and first class passengers are not immune, so more generous seating space is unlikely to be the answer (and "economy class syndrome" is most likely a misnomer). The following general advice has no direct supporting evidence but is common sense, harmless, inexpensive, and likely to be appropriate, particularly for flights longer than 6-8 hours.18,19 These general precautions are directed at preventing venous stasis and include regular foot exercises to activate the plantar and calf muscle pumps, a generous fluid intake, avoiding excessive alcohol (especially when combined with the use of hypnotics), and wearing loose clothing while travelling. Prolonged movement about the cabin during flight is discouraged because this may bring other hazards, including from unexpected clear air turbulence. Travellers with an above-average risk of thrombosis should seek specific medical advice on additional preventive measures before travelling. Case series suggest that people with previous VTE, chronic venous insufficiency, recent surgery, chronic heart and lung disease, cancer, old age and those who are overweight are all at greater than average risk. Oral contraceptives, hormone replacement and inherited thrombophilia (including factor V Leiden) may predispose, but there is no good published evidence for this. Screening for factor V Leiden (activated protein C resistance) is not recommended in this or any other context if there is no personal or family history of VTE, as about 5% of people of European descent have this polymorphism, and most will never develop thrombosis.11 As a generalisation, it usually takes two or three risk factors acting together to provoke VTE,11 and, as this is likely to apply also in travellers, it is people with several concurrent risk factors who are most likely to require specific prophylaxis. Aspirin alone is not likely to be appropriate, as the evidence that aspirin prevents DVT or PE is highly controversial and the plausible level of risk reduction is small.20,21 Prescribing aspirin for all travellers may also cause sufficient excess bleeding to negate any benefit. Graded pressure support stockings to be worn during flight must be carefully fitted: too tight and they become a tourniquet, too loose and they are ineffective. And they are contraindicated in some people with advanced peripheral vascular disease. People at highest risk (including those with previous VTE) should consider self-injecting a low molecular weight heparin before and perhaps for some days after travel. Few people die of PE without some warning from unexpected breathlessness, chest pain, or leg symptoms. Information kits about DVT and PE, predisposing factors and various clinical presentations should therefore be widely distributed to travellers before they leave home. People should know that, although symptoms of VTE may arise during flight, they are more often first noticed some time after landing. More importantly, we need better evidence. If the present media crisis and federal inquiry brings a greater awareness that VTE may develop during or soon after prolonged travel, and if it triggers a productive collaboration of airlines with investigators to measure the real risk and evaluate preventive measures, then it will have served a useful purpose. Alex S Gallus Professor of Haematology and Director of Pathology Services Flinders Medical Centre and Repatriation General Hospital Adelaide, SA Ross I Baker Director, Thrombosis and Haemophilia Service, Royal Perth Hospital and Clinical Senior Lecturer in Medicine, University of Western Australia Perth, WA Homans J. Thrombosis of the deep leg veins due to prolonged sitting. N Engl J Med 1954; 250: 148-149. Cruikshank JM, Gorlin J, Jennett B. Air travel and thrombotic episodes: the economy class syndrome. Lancet 1988; 2: 497-498. Clerel M, Caillard G. Thromboembolic syndrome from prolonged sitting and flights of long duration: experience of the Emergency Medical Service of the Paris Airports. Bull Acad Natl Med 1999; 183: 985-997. Sarvesvaran R. Sudden natural deaths associated with commercial air travel. Med Sci Law 1986; 26: 35-38. Ribier G, Zizka V, Cysique J, et al. Venous thromboembolic complications following air travel. Retrospective study of 40 cases recorded in Martinique. Rev Med Interne 1997; 18: 601-604. Paganin F, Laurent Y, Gaüzere BA, et al. Pulmonary embolism on non-stop flights between France and Reunion Island [letter]. Lancet 1996; 347: 1195-1196. Eklof B, Kistner RL, Masuda EM, et al. Venous thromboembolism in association with prolonged air travel. Dermatol Surg 1996; 22: 637-641. Mercer A, Brown JD. Venous thromboembolism associated with air travel. Aviat Space Environ Med 1998; 69: 154-157. Tardy B, Page Y, Zeni F, et al. Phlebitis following travel. Presse Medicale 1993; 22: 811-814. Van Beek ER, BŸller HR, ten Cate JW. Epidemiology of venous thromboembolism. In: Tooke JE, Lowe GDO, editors. A textbook of vascular medicine. London: Arnold, 1996: 471-488. Rosendaal FR. Venous thrombosis: a multicausal disease. Lancet 1999; 353: 1167-1173. Ferrari E, Chevallier T, Chapelier A, Baudouy M. Travel as a risk factor for venous thromboembolic disease: a case-control study. Chest 1999; 115: 440-444. Kraaijenhagen RA, Haverkamp D, Koopman MMW, et al. Travel and risk of venous thrombosis. Lancet 2000; 356: 1492-1493. Bounameaux H. Thromboembolism and air travel [letter]. Lancet 1988; 2: 797. Carruthers M, Arguelles AE, Mosovich A. Man in transit: biochemical and physiological changes during intercontinental flights. Lancet 1976; 1: 977-981. Simons R, Krol R. Jet lag, pulmonary embolism, and hypoxia. Lancet 1996; 348: 416. Bendz B, Rostrup M, Sevre K, et al. Association between acute hypobaric hypoxia and activation of coagulation in human beings. Lancet 2000; 356: 1657-1658. Kesteven PL. Traveller's thrombosis. Thorax 2000; 55 (Suppl 1): S32-S36. Ferriman A. Travellers should be warned of thrombosis risk. BMJ 2000; 321: 1310. Sors H, Meyer G. Place of aspirin in prophylaxis of venous thromboembolism. Lancet 2000; 355: 1288-1289. Cohen A, Quinlan D. PEP trial [letter]. Lancet 2000; 356: 247. Make a comment

Alex S Gallus · Ross I Baker

Water Hazards Dead in the water: how safe are our water sports? We now have the Australian Water Safety Council and its National Water Safety Plan: the impact of these initiatives remains to be seen MJA 1999; 171: 584-586

Robyn M Walker

Water Hazards Snorkelling deaths in Australia, 1987-1996 Carl W Edmonds and Douglas G Walker MJA 1999; 171: 591-594 For editorial comment, see Walker Abstract - Introduction - Methods - Results - Discussion - Acknowledgments - References - Authors' details - - More articles on Travel, aviation and underwater medicine

Carl W Edmonds · Douglas G Walker

Water Hazards Scuba diving medical examinations in practice: a postal survey Graham Simpson and David Roomes MJA 1999; 171: 595-598 For editorial comment, see Walker Abstract - Introduction - Methods - Results - Discussion - References - Authors' details - - More articles on Travel, aviation and underwater medicine

Graham Simpson · David Roomes