- Part 2

Wrong-site surgery (performing surgery on the wrong side, wrong body part, wrong patient, or using the wrong prosthesis) is very rare, but is the most common surgical mistake. And, at least in theory, it should be easily avoided.

Ten years ago I was the RANZCO representative on a multi-disciplinary Queensland Health committee that developed Queensland Health’s correct site surgery policy and protocol. This was quite educational because around the world there are a variety of protocols that attempt to prevent this complication, and not all of them work. Some are too complicated, which means people in busy hospitals may skip steps or make errors in following the policy itself.

One research paper in the Archives of Surgery found that the incidence of wrong site surgery was less than 1 in 100,000 operations, and that most of these did not result in significant problems, but that existing protocols would only have avoided about two thirds of these. Protocols were often too complex and ineffective.

In Queensland there are 4 steps: identify the patient, check informed consent, mark the site with the patient awake, and a final check in which surgeon, scrub nurse and anaesthetist check patient, side, planned operation and prosthesis before starting.

For patients this constant checking and double-checking can be a bit tedious, but this is a simple and pretty quick way of eliminating this avoidable error.

Reference:

MR Kwaan et al.Incidence, patterns, and prevention of wrong-site surgery. Arch Surg. 2006 Apr;141(4):353-7; discussion 357-8.

Last weekend I attended the AMA National Conference in Canberra to see The President’s Medal awarded posthumously to Dr Bernard Quin. Dr Quin was an Australian doctor working in Nauru in the 1930’s, and then into the early years of the Second World War whilst Australian soldiers were stationed there. He cared for Australian workers and soldiers, and the broader local community, including a “leper colony”. After the withdrawal of Australian troops he stayed behind to continue to care for his patients while his young family were moved to safety in Melbourne. Japanese forces occupied the island and a little over 6 months later Dr Quin was murdered, along with 4 other Australians, in retaliation for an Allied raid.

I was excited to see the presentation, partly because my wife Dr Angela Ryan had been working very hard for a long time to get some form of recognition for Dr Quin. We had come to know his story through his son, Fr Peter Quin, who christened our son, and we had both been deeply affected by it. But I was also excited to witness this presentation because Dr Quin fully embodied an ideal, that of placing the welfare of our patients first. As doctors we hope to be capable of this, and recognizing a sacrifice such as his can renew our faith that this ideal, while extraordinary, is not lost to us.

Why didn’t cavemen need glasses?

I am frequently asked for advice about avoiding or ameliorating myopia, or short-sightedness, so I was interested to read a piece in The Courier Mail recently (“Caving in to the accidental diet”, Sue Dunlevy and Sarah Orr) discussing the Paleo Diet. Dunlevy and Orr quote Loren Cordain, an exercise physiologist at Colorado State University, advocate for the Paleo diet, and a researcher that has previously published an hypothesis that relates the modern observed increased prevalence of myopia to modern changes in diet. Online experts/advocates for the Paleo diet have claimed numerous health benefits on its behalf, so what’s this all about?

The Paleolithic Diet (“Paleo Diet” is trademarked) is an attempt to adopt assumptions about what early humans ate (during the “Paleolithic Era”, which ended around 10 000 years ago) and adapt them to a modern post-industrial society. The reasoning is that since we evolved to eat the diet of early humans, we should be more healthy doing so. The enthusiasm for it is based on observations made since the late 19th and early 20th century that many of the “diseases of civilization” (eg diabetes, heart disease, appendicitis, cancer, and myopia) were unknown in pre-agricultural societies when those societies were first encountered by modern doctors, but became common once these same societies transitioned to a Western diet and Western lifestyles were adopted. Some knowledge of the diet of early humans can be derived from the activity of modern hunter-gatherers, but much is derived from archeological enquiries that are properly in the field of paleo-anthropology.

From modern hunter gatherers we know that the prevalence of myopia is extremely low, around 1% or so, in pre-agricultural/pre-Industrial humans. In Western countries it is significantly greater (more than 15% in Australian adults), and higher still in Asian countries. There is significant evidence that this disparity is multifactorial, and correlates with parental education and numbers of books read amongst other factors, and inversely correlates with time spent outdoors. Cordain’s hypothesis is that high GI diets (diets high in refined carbohydrates that the body quickly breaks down to glucose, ie white flour, white rice, sugar) lead to an increase in insulin secretion, which has a number of biochemical consequences in the body. These include suppression of IGF-binding protein-1 (IGFBP-1), and increased IGF-1 (insulin-like growth factor-1). This can have effects on tissue growth, but also may lead indirectly to suppression of IGF-binding protein-3 (IGFBP-3), leading to effects on retinoid receptor signaling in the eye.

It’s an intriguing hypothesis, but there are a few problems with adopting a stone-age diet to treat your myopia. Firstly, working out what stone-age man ate on a day-to-day basis is more difficult that you might think, and adopting such a diet even harder. Hunter-gatherers forage and hunt, and eat everything when they hunt, often prizing organs such as liver and brain. Secondly, when modern hunter-gatherers hunt and forage, they typically cover a lot more ground than most city dwellers (15km daily for men, 9km daily for women). In the Paleolithic early man probably hunted by running-down prey, in what is termed “persistence hunting”, covering even more ground. So if you want to live like a caveman, get out and run!

That’s not to say that evolution can’t teach medicine anything. Quite the opposite. Learning about how we evolved to become human teaches us quite a lot about what it means to be human, at least as far as our bodies are concerned. Our modern diets and lifestyles would be unimaginable to our pre-agricultural cousins, and for all the technological improvements that have helped us treat infections and other diseases, we are spending more of our healthcare resources treating diseases that are, to a very large extent, caused by the way we live. Spending more time on our feet and eating less highly processed foods intuitively make sense, and find support in the available research. But the relationship of diet to myopia progression is more problematic.

Part of the problem is the interpretation of available data, which is often colored by the prism of the established low-fat diet dogma. A relatively recent study of Singaporean children in which diet was assessed by a survey completed by the children, and then stratified according to carbohydrate, total fat, cholesterol, saturated fat and polyunsaturated fat intake, concluded that myopia progression is associated with cholesterol intake. The data, included with the paper, is difficult to reconcile with the author’s conclusion, and appear to me to support only a conclusion that dietary fat, cholesterol and carbohydrate have no apparent impact on myopia progression.

We need to be very careful when assessing research that advocates changes in the way we live our daily lives. Having a better understanding of where we came from May help this. But recognizing that is understanding is a work in progress is paramount.

@doctor_forrest

Cordain L, Eaton SB, et al. An evolutionary analysis of the aetiology and pathogenesis of juvenile-onset myopia. Acta Ophthalmol Scand. 2002 Apr;80(2):125-35.

Lim LS, Gazzard G, et al. Dietary factors, myopia, and axial dimensions in children. Ophthalmology. 2010 May;117(5):993-997

Could Hormone Replacement Therapy protect against Glaucoma? Several studies have asked this question before, with equivocal findings. The Rotterdam & Blue Mountain Eye Studies both found a reduced risk, though it didn’t reach statistical significance, while the Los Angeles Latino Eye Study found no protective effect.

This month in Jama Ophthalmology (the journal “formerly known as” Archives of Ophthalmology) researchers from the University of Michigan published a large claims-based study that included data from the records of more than 150 000 women over 50 that showed a statistically significant reduction in the risk of glaucoma in those on estrogen. There appeared to be a larger reduction in risk in those on estrogen plus progesterone, but after adjustment for age, sociodemographic factors and other health issues, this reduction in risk was not statistically significant.

The study used billing data from a managed care network, so there may have been selection bias as the study cohort may have had a disproportionately low number of racial/ethnic minorities and socially disadvantaged people. Nevertheless the study findings are interesting given previous clinical studies showing that HRT may lower intraocular pressure, and lab studies showing the presence of estrogen receptors in human retina, and a protective effect from oral estrogen on retinal ganglion cell loss (the mechanism of vision loss in glaucoma) in a rat model.

Study:

P Newman-Casey, N Talwar, B Nan, D Musch, LR Pasquale, JD Stein. The Potential Association Between Postmenopausal Hormone Use and Primary Open-Angle Glaucoma. JAMA Ophthalmol. 2014;132(3):298-303.

Next week my wife Angie Ryan will host a fundraising evening to support a charity called Destiny Rescue. We became aware of this charity around the time of my trip to Cambodia late last year because my son’s English teacher from 2013, Tanya Mathias, has taken leave this year to teach in Phnom Penh as a volunteer.

The charity seeks to rescue and rehabilitate sexually enslaved children and young girls.

The trafficking of children, particularly for work in the sex industry, is especially heinous and is growing. Cambodia is becoming a magnet for sex tourism for Asian and Western tourists, partly because of an increase in tourism for all reasons, but also because of a “perfect storm” of a tougher Thailand, rampant poverty (especially in rural areas), governmental and judicial corruption and a social fabric that is still recovering from decades of trauma including genocide and civil war.

Although the Cambodian police work hard to curb this trade, and convictions are increasing, the rescue and rehabilitation of abused women and children is frequently left to NGOs and charities. Destiny Rescue is one of these, and one that, through Tanya, we have a personal connection with.

Earlier this month I went to Cambodia as a volunteer on behalf of Sight For All (SFA) a charity I have blogged about before. The project I’m involved with sends Australian ophthalmologists to help locally-trained ophthalmologists develop sub-specialty skills. It’s a great cause and SFA has demonstrated impressive results, with projects also ongoing in Myanmar, Vietnam, Laos, Bhutan, Nepal and other Asian countries. The founder and head of SFA is Dr James Muecke AM, a man of true vision and relentless energy who has succeeded in drawing together a team of ophthalmologists from all around Australia. It’s a privilege to be included with the team, and it’s a wonderful project to work on.

I hadn’t been to Cambodia before this visit, I had little idea what to expect when I got there, but I almost immediately fell in love with the place. Cambodians have suffered almost unimaginable trauma, and live in society governed by a political system almost universally recognized as dysfunctional, with endemic corruption and intimidation of dissenters.

And yet this young country, with a median age of less than 24, remains optimistic for the future. Cambodia ruled most of Southeast Asia for almost 600 years, and the recognition of that history is an important part of the national psyche. Reminders of it reside above all in the image of Angkor Wat, which adorns the national flag, beer labels and bill boards. For the last 2 weeks Phnom Penh has seen rolling political rallies culminating in a huge protest yesterday in which supporters of the opposition and striking garment workers filled almost the entire length of one of the central boulevards. Did you see it on the news? No, neither did I.

Most of the world stopped looking closely at Cambodia some time ago, and left the task of assisting Cambodians in their ongoing recovery to NGOs and charities. Which is a shame, because I think we could be watching something like a Phoenix rising from its ashes. Well, at least we have Twitter …

Please see consider donating to SFA. Helping to prevent blindness isn’t a bad New Year’s resolution.

Last month Dr David Hubel died, aged 87. He was a giant in visual neuroscience, and his work with Dr Torsten Wiesel led to the collaborators sharing (with Roger Sperry) the 1981 Nobel in Physiology or Medicine.

“Hubel & Wiesel”’s work on visual processing in the cerebral cortex showed that the brain breaks down visual information into component parts for processing, before relaying it on to higher centres where it is reassembled and an image perceived. They discovered and described a visual cortex in which cells are arranged in “orientation columns” that respond to line stimuli of different angles, and “ocular dominance columns” perpendicular to the orientation columns, that respond to input from one eye or the other.

Hubel & Wiesel described the anatomical and physiological basis for amblyopia, in which any condition that interferes with sight during a critical period of development can lead to loss of vision due to the failure of connections between the eye and brain. It is no exaggeration to say that their work underpins all of paediatric eye care.

Vale Dr Hubel.

As I’ve written before, macular degeneration is the leading cause of blindness in Australia, and 1 in 7 Australians over 50 suffer from it. Although the wet, aggressive, neovascular form is justifiably feared, there are pharmacological treatments widely available that for many patients salvage or restore vision. The dry, atrophic, form remains untreatable, and in some patients it inexorably progresses to its most advanced form, geographic atrophy (GA). In patients with GA there may be no functional macula tissue remaining, and central vision is lost.

Because dry AMD is untreatable, identifying and managing modifiable risk factors is very important. Avoiding exposure to cigarette smoke and increasing intake of fresh leafy green vegetables (high in lutein/zeaxanthin amongst other things) are well known strategies but a number of studies have also looked closely at the relationship between fatty acid (FA) intake and AMD. Total fat intake, saturated fat intake, trans-unsaturated FA intake and omega-6 FA intake have all been associated with increased risk of advanced AMD. This is particularly important because over the last several decades many people heeding well-intentioned health advice have attempted to reduce their saturated fat intake by replacing saturated fat in their diet with polyunsaturated vegetable oils (very high in omega-6 FA and now almost ubiquitous in processed foods) and their partially-hydrogenated derivatives which contain trans-fats.

A study in the current issue of Ophthalmology investigated the effect of dietary omega-3 FA on the progression of dry AMD to GA. The team, from Tufts University in Boston, found that increased intake of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), the omega-3 FA found in fatty fish, was associated with reduced risk of progression, and reduced the effect of genetic susceptibility. They recommend that eating one or more 90g servings of fish high in omega-3 (eg salmon, herring, mackerel and sardines) may reduced the risk of progression.

The authors didn’t advocate omega-3 supplements. Rather, they suggested increasing fish intake. This is an distinction that is increasingly coming to be understood as important. Nutrients do not exist in isolation in nature, and don’t come traditionally to our diets readily labelled and understood. The traditional mediterranean diet, for example, is known to be high in both fresh leafy green vegetables, and olive oil. Although olive oil contains a high percentage of monounsaturated FA, it has been shown to increase the absorption of lutein from leafy green vegetables in laboratory rats. Making recommendations to patients for dietary change means thinking about more than isolated nutrients, or packaged supplements. It means considering diet as a whole, in the context of the whole person.

Papers:

R Reynolds et al. Dietary omega-3 Fatty acids, other fat intake, genetic susceptibility, and progression to incident geographic atrophy. Ophthalmology. 2013 May;120(5):1020-8.

R Lakshminarayana et al. Lutein and zeaxanthin in leafy greens and their bioavailability: olive oil influences the absorption of dietary lutein and its accumulation in adult rats. J Agric Food Chem. 2007 Jul 25;55(15):6395-400.

The emergence of “superbugs”, bacteria resistant to multiple antibiotics, is shaping up as one of the greatest world-wide health-care challenges of the (still relatively) new century. Infectious Diseases (ID) Physicians warn of a coming “Red Plague” that threatens to effectively take us back to the pre-antibiotic era, when people died of what are currently considered minor infections, due to increasing Gram-negative resistance.

Gram-negative bacteria (including Enterobacteriaceae such as Escherichia coli [E.coli] & Klebsiella, and Pseudomonas and the Neisseriae) don’t retain crystal violet during the Gram stain process and so appear red under the microscope, hence the name “Red Plague”. Bacterial populations can develop resistance after exposure to particular antibiotics in humans, other animals or the environment, but they are also able to inherit resistance through “horizontal gene transfer” of plasmids (DNA molecules that exist within bacteria separate to their chromosomal DNA) which can be shared between species. A combination of widespread antibiotic use, both clinically and in agriculture, poor sanitation in developing countries that have relatively unrestricted access to antibiotics, and international travel have contributed to a dramatic increase in the incidence of dangerous multiple drug-resistant Gram-negative infections – Carbapenem-resistant Enterobacteriaceae (CRE) caused 17 infections in the UK in 2008, but 799 last year. And we are running out of antibiotics to use against them.

In this week’s Medical Journal of Australia (MJA), doctors in Brisbane reported the case of a man who experienced an horrific spread of infection due to multi-resistant E.coli after a procedure he required in order to diagnose his prostate cancer. He probably picked up the bacteria during a trip to South-East Asia, but was unaware of it as he didn’t get sick. Infection spread from his bowel to his prostate, and then to his sterno-clavicular joint (the joint between the collar-bone and breast-bone), and lumbar spine. He endured 10 weeks of IV antibiotics and 8 weeks of oral antibiotics.

Last week New Scientist reported that new antibiotics for multi-resistant bacteria are in the development pipeline, but aren’t being picked up by drug companies for development because with the high costs of bringing new drugs to market antibiotics are not considered a profitable investment. Unlike medications for chronic illness like heart disease or high cholesterol, antibiotics are used for short courses, and antibiotics for high-risk multi-resistant infections are deliberately used as infrequently as possible, so the opportunity to recoup on an investment by a pharmaceutical company that is ultimately answerable to its shareholders, rather than the public, its clients, isn’t seen to be there.

Again in the MJA this week, David Looke, Thomas Gottlieb, Cheryl Jones and David Paterson, highly respected ID Physicians in Brisbane and Sydney, authored an editorial in which they offered a series of recommendations to deal with this urgent problem:

1. implementation of national surveillance to follow these infections

2. implementation of antibiotic stewardship in all health-care sectors so that antibiotic use is appropriate

3. support & funding for research (the US Congress and European authorities are revising the mechanisms for bringing new drugs to market so that antibiotics are not so costly to develop – there will be an inevitable trade-off in safety)

4. embrace

a. innovative trials of preventive strategies, such as vaccines

b. interventional radiology & minimalist surgical techniques

c. agriculture that doesn’t require antibiotics

5. understand the importance of this “red-plague” as we do bird-flu.

This is a global problem and it requires a global response, but ultimately we doctors are primarily concerned with the patient in front of us. Endophthalmitis (intraocular infection) is the most feared complication of cataract surgery, and thankfully is very rare, and usually due to Gram-positive organisms. But as an ophthalmologist I treat patients with Gram-negative infections regularly and emerging resistance is a real threat.

Articles:

David F M Looke, Thomas Gottlieb, Cheryl A Jones and David L Paterson. Gram-negative resistance: can we combat the coming of a new “Red Plague”? Med J Aust 2013; 198 (5): 243-244.

Kelly A Cairns, Adam W J Jenney, Iain J Abbott, Matthew J Skinner, Joseph S Doyle, Michael Dooley and Allen C Cheng. Prescribing trends before and after implementation of an antimicrobial stewardship program. Med J Aust 2013; 198 (5): 262-266.

Despina Kotsanas, W R P L I Wijesooriya, Tony M Korman, Elizabeth E Gillespie, Louise Wright, Kylie Snook, Natalie Williams, Jan M Bell, Hua Y Li and Rhonda L Stuart. “Down the drain”: carbapenem-resistant bacteria in intensive care unit patients and handwashing sinks. Med J Aust 2013; 198 (5): 267-269.

Matthew J Roberts, Anisha Parambi, Lucinda Barrett, Paul Hadway, Robert A (Frank) Gardiner, Krispin M Hajkowicz and John Yaxley. Multifocal abscesses due to multiresistant Escherichia coli after transrectal ultrasound-guided prostate biopsy. Med J Aust 2013; 198 (5): 282-284.

Debora MacKenzie. Antibiotic resistance an ‘apocalyptic threat’. New Scientist. 13 March 2013.

Hypertension (high blood pressure) is one of the most common medical conditions seen by doctors in Australia and other Western industrialised countries, and causes more deaths than any other cardiovascular risk factor, including smoking and high cholesterol. Although we understand the role of lifestyle factors and have many medications available to treat hypertension, for many patients and doctors it remains frustratingly difficult to control, and in many patients remains undetected. In the American National Health and Nutrition Study (NHANES III) 68.4% of hypertensive patients were aware of their hypertension, 53.6% were being treated, and only 27.4% had control of their hypertension. These figures are worrying because inadequate control of hypertension can lead to “end-organ damage” including kidney disease, peripheral vascular disease, eye disease, stroke and heart attack.

Hypertension is diagnosed when the blood pressure is over 140/90. Some people may be nervous being examined by a doctor and “white coat hypertension” is the phenomenon when your hypertension is only detectable when your doctor checks it. In these cases home monitoring or 24 hour ambulatory monitoring may be required. Malignant hypertension occurs when the blood pressure is over 200/140, and the risk of rapid end-organ damage, including vision loss, makes this a medical emergency.

Although chronic low grade hypertension rarely causes visual loss on its own, it is an important risk factor for a number of conditions that can lead to loss of vision, such as vein occlusion and macro-aneurysm. Malignant hypertension commonly causes visual loss, through direct effects on the retina, choroid or optic nerve.

Patients with hypertension frequently have changes in their retinal blood vessels, which are apparent on careful clinical examination. It’s not uncommon that I discover hypertensive retinal changes on a routine eye examination of someone that hasn’t previously had high blood pressure detected.

Your eyes certainly are a window onto your general health.

Reference: Burt VL et al. “Trends in the prevalence, awareness, treatment and control of hypertension in the adult US population: data from the Health Examination Surveys, 1960–1991”. Hypertension. 1995;26:60.

Dr Michael Forrest

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