Ghost in the machine?

A friend forwarded this article to me from the BMJ archives. I thought it made very good reading sense for my medical colleagues on a Sunday!

"Recently, I was the anaesthetist for some elective caesarean sections. All was running smoothly, with relaxing background music in dimmed ambient light. Despite this, one mother was very anxious about the impersonal medical environment. Thus when the baby was delivered, I allowed her to touch her newborn without any “foreign body” interfering. Not thinking too much, I took the saturation probe off her finger and clipped the probe onto the drip chamber of the infusion set. To my intense surprise, not only did the screen come up with a regular waveform, resembling an electrocardiograph trace rather than an artefact, but it also displayed the “oxygen saturation” of the bloodless solution and the rate of drops infused per minute (figure).Pulse oximeters are used to determine arterial oxygen saturations by using oximetry and Beer-Lambert’s law.1 Diodes send out light of the required wavelength, usually in the red and infrared spectrum as absorbance of body tissues in this range is small. Therefore absorbance essentially results from the presence of oxygenated or deoxygenated haemoglobin. A photometer on the opposite side of the probe detects the transmitted light. The signal is converted to a DC component, representing venous blood and tissue, and an AC component, representing pulsatile flow. Only the latter component is amplified and averaged over a few cycles. Inaccuracies are the result of several factors, including bright ambient light, movement, electrical interference, venous congestion, and various pigments or molecules (such as nail polish, bilirubin, carboxyhaemoglobin, methaemoglobin, or methylene blue).A near-infrared laser at a wavelength of 830 nm was used previously to measure lactic acid non-invasively.2 As Ringer’s solution was infused on this occasion, the lactate component (about 28 mmol/l) of the balanced crystalloid is the likely culprit, causing signal extinction and the generation of a numerical value for “oxygen saturation.” A gelatin solution was later tested, achieving a trace of inferior quality and lower readings. Physiological saline solution on the other hand produced a stronger signal, but even lower saturations. Both traces looked very much like artefacts compared with the one produced by Ringer’s lactate.So what about the pulsatile flow—surely, there was none? Although this all happened just around Hallowe’en, surely there was no supernatural spirit in the machine? No, in fact, it was the regular intermittent light absorption, induced by the falling drops, that had fooled the sensor into recognising an AC component and then displaying a “pulse rate.” - Andreas Kopka
Andreas Kopka is a consultant anaesthetist Greater Glasgow University Hospitals, Southern General Hospital, Glasgow G51 4TF a.kopka@doctors.org.ukI
Not commissioned; not peer reviewed.
1 Davis PD, Parbrook GD, Kenny GNC. Basic physics and measurement in anaesthesia, 4th ed. Oxford: Butterworth-Heinemann, 1998.
2 Pilotto S, Pacheco MTT, Silveira Jr L, Balbin Villaverde A, Zangaro RA. Analysis of near-infrared Raman spectroscopy as a new technique for a transcutaneous non-invasive diagnosis of blood components. Lasers in Medical Science 2001;16:2-9.

Chicken Soup For The Beer

"Sometimes when I reflect back on all the beer I drink I feel shamed. Then I look into the glass and think about the workers in the brewery and all of their hopes and dreams. If I didn't drink this beer they might be out of work and their dreams would be shattered. Then I say to myself, "It is better that I drink this beer and let their dreams come true than be selfish and worry about my liver."
~ Jack Handy


"I feel sorry for people who don't drink. When they wake up in the morning, that's as good as they're going to feel all day. "
~Frank Sinatra

"When I read about the evils of drinking, I gave up reading."
~ Henny Youngman

"24 hours in a day, 24 beers in a case. Coincidence? I think not."
~ Stephen Wright

"When we drink, we get drunk. When we get drunk, we fall asleep. When we fall asleep, we commit no sin. When we commit no sin, we go to heaven. Sooooo, let's all get drunk and go to heaven!"
~ Brian O'Rourke

"Beer is proof that God loves us and wants us to be happy."
~ Benjamin Franklin

"Without question, the greatest invention in the history of mankind is beer. Oh, I grant you that the wheel was also a fine
invention, but the wheel does not go nearly as well with pizza."
~ Dave Barry

BEER: HELPING UGLY PEOPLE HAVE SEX SINCE 3000 B.C.!!!
~ "Unknown"

Remember "I" before "E", except in Budweiser.

To some it's a six-pack, to me it's a Support Group. Salvation in
a can!

And saving the best for last, as explained by Cliff Clavin, of Cheers. One afternoon at Cheers, Cliff Clavin was explaining the
Buffalo Theory to his buddy Norm. Here's how it went:
"Well ya see, Norm, it's like this... A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it is the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members. In much the same way, the human brain can only operate as fast as the slowest brain cells. Excessive intake of alcohol, as we know, kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine. That's why you always feel smarter after a few beers.

Dark Humor

Lesbian Whips Lawsuit

A lesbian woman, from California, US, is appealing a court decision that upheld a decision made by her doctors to withhold fertility treatment from her on religious grounds. Her case will be heard in the California Supreme Court, the highest court in the state, after having been heard in various courts over the past five years. The woman, Guadalupe Benitez, who is now 33, was kept on a waiting list for fertility treatment for almost two years, before she was told that neither of her two doctors - Christine Brody and Douglas Fenton - would treat her. She claims that each doctor said that treating her and allowing her to have children, because of her sexual orientation, conflicted with their religious beliefs. Both of the doctors deny that this was the reason they denied her treatment, and say that it was the fact she is unmarried that was the deciding factor. However, at the time, Ms Benitez had been with the same partner for 15 years, and the couple had also legally registered their domestic partnership. Since the case was originally filed, Benitez has received fertility treatment elsewhere and given birth to a son, now three years old, and twin daughters.
Ms Benitez's case was initially unsuccessful in the state courts, but she won an appeal three years ago, the court finding that patients can sue health care providers who discriminate against patients on the basis of sexual orientation, and that federal law does not exempt health care providers from the civil rights laws. Later, in 2004, a court found that doctors working in the commercial sector must comply with the State's anti-discrimination laws and treat all patients equally, whatever the religious beliefs of the individual doctors. However, on appeal by the doctors, this decision was later overturned.
Jennifer C. Pizer, one of the lawyers acting for Ms Benitez, said that 'our client's doctors' behaviour goes against established medical ethics and violates California civil rights law'. She added that the 'doctors claim a right not to comply with California's civil rights law because they are fundamentalist Christians and they object to treating a lesbian patient the same way they treat other patients'. Ms Benitez said that she was intent on taking the case as far as it would go as the doctors 'humiliated my family and me by refusing to perform the insemination procedure after they'd been treating me and promising it to me for nearly a year'. She added 'I don't want anyone else to have to suffer the humiliating treatment by their doctors that I endured'.

"Micro-Bubbles" Boost Diabetes Gene Therapy Research

Scientists at Baylor University Medical Center in Texas, US, have developed a novel method of delivering an insulin gene into the pancreas of experimental rats in a potential breakthrough in diabetes research. The researchers injected the rats with microscopic spherical shells enclosing a gene that codes for insulin, which is not produced correctly in the pancreas of diabetes sufferers. The team then directed an ultrasonic pulse at the rats' pancreas, which broke the 'bubble' enclosing the new DNA. This method allows the gene to be delivered to a specific location, crucial in diabetes and until this point one of the biggest barriers to gene therapy.
Previous attempts at gene therapy have relied on the use of harmless viruses engineered to carry the healthy gene. These viruses are injected into the animal or person and the harmless virus and the new, desirable, gene become incorporated into the host's DNA. Gene therapy has a controversial history as this method has the potential for a dangerous immune response, thought to be responsible for the death of teenager Jesse Gelsinger in 1999 whilst undergoing gene therapy for a rare liver disorder. As well as the potential for a dangerous immune response this method does not allow the gene to be targeted to a particular location or organ. Pancreatic cells are the only cells in the body which are fine-tuned to release the correct levels of insulin in response to food intake. If other cells in the body were to pick up and start producing insulin the results could be disastrous. Speaking to the New Scientist, Mark Kay, from the Stanford University School of Medicine, explained that 'the results would be willy-nilly - you'd more likely die from hypoglycaemic shock than the high blood sugar levels' that characterise diabetes.
The team at Baylor injected the bubbles - made with a shell of water insoluble molecules - into rats. The bubbles that were initially injected contained an inert circular piece of DNA - known as a plasmid - engineered with a gene that codes for a fluorescent protein marker. The technique, known as 'ultrasound targeted microbubble destruction', involves using ultrasound waves directed at islet cells in the pancreas. These waves break bubbles in nearby blood vessels which consequently release the gene; the waves also break holes in the membranes of adjacent cells creating a passage for the genes to enter through. After breaking the bubbles in the rat pancreases using the directed ultrasound pulse, researchers dissected the animals and found higher levels of fluorescence in the pancreas than in other areas.
In further experiments the researchers injected bubbles containing a plasmid which had the human gene for insulin engineered into it. Again, after bursting the bubbles researchers dissected the rats and found significantly elevated levels of human insulin in the rodents. The animals' blood sugar levels also dropped compared with rats that were used as controls. 'This work shows that genes can be targeted to pancreatic islets in living, adult animals', commented Paul Grayburn, the cardiologist at Baylor who led the study, published in the Proceedings of the National Academy of Sciences. The next big challenge with this therapy will be developing it so that the effect lasts for a long time - currently the protein produced by the new gene can only be detected for around three weeks after treatment.

FINDING TRAVEL INSURANCE THAT COVERS PEOPLE WITH MEDICAL CONDITIONS

Dear Friends,
I came across this nugget on the net. I really thought it worthwhile to share this British article with you.

"Last November, the UK's Genetics and Insurance Committee held a meeting on Family History, Genetics and Insurance, which included presentations providing advice to people with a serious medical condition on buying insurance. This article deals with buying travel insurance if you are affected by a genetic condition, or indeed any long-term medical condition. Finding the right travel insurance policy can be more difficult if you have been diagnosed with a serious health condition. This need not be a major worry, as insurance will be available in almost all cases, but you do need to make sure you shop around with the right insurers. People diagnosed with health conditions will, however, find they usually pay more for travel insurance than people with no serious health issues. This is because they typically present insurers with a higher likelihood of making an expensive medical-related claim. Travel insurers are not concerned with your genetic susceptibility to health conditions and will not ask for the results of predictive genetic screening before selling you a policy. But they do need to know if you have an actual diagnosis of illness. Travel insurance is designed principally to help you pay for emergency medical help while abroad, which is by far the most costly risk people typically face when travelling, and the reason you pay more for cover if you present a higher medical risk. The figures below from the Foreign Office website illustrate the typical costs of getting you home to the UK after a medical emergency:
£30-35,000: Air ambulance from East coast of USA
£15-20,000: Ordinary scheduled flight with doctor escort from Australia
£12-16,000: Air ambulance from Canaries
£10-12,000: Air ambulance from Balearics
£3-£6,000: Ordinary scheduled flight, with stretcher and Doctor escort from Mediterranean
£1,200-3,000: Air taxi (light aircraft) from Northern France
So, in spite of the higher cost you can pay if you have an illness, travel insurance is still well worth buying. The costs of emergency help are high in places that do not offer free health care, such as North America, but even in Europe, emergency medical repatriation to the UK can cost thousands.It is also the case that not all insurers are able to provide cover to
people with serious conditions, such as active cancers. This is because they will not have the right experience in underwriting these risks. In these cases, you will need to contact one of the many specialist insurers on the market.
Here are some useful tips on finding insurance if you have a medical condition:
- Don't always rely on the mass-market insurers, or tour operators that sell insurance as part of a package holiday. Some of these won't be able to cover medical conditions, especially very serious ones.
- Go to specialists - more and more insurers have specialist knowledge of medical conditions and can offer you cover. Some companies specifically market to people with pre-existing medical conditions.
- Shop around - insurance policies differ on both cover and price, so compare the quotes you receive to find the best deal.
- If you have any problems trying to find specialist insurers, use a broker.
They can do the work for you. You can contact a broker through the British Insurance Brokers Association, who host a website and a dedicated customer helpline: Telephone: 090 1814 0015; Email: enquiries@biba.org.uk
The most important thing to remember if you have a medical condition is not to leave insurance until the last minute: make it a key part of your travelling plans and shop around with the right providers to get the best deal.
- Sean Worth, UK Association of British Insurers

Unknown Sperm Donor Passes Disease to Five Children

Doctors have discovered that a sperm donor in the US has passed on a rare genetic disease to five children born to four couples who used his sperm to conceive. The disease, severe congenital neutropenia (SCN), can be fatal in children if untreated but is so rare that sperm banks do not typically test for it. Even though donors are asked to give full details about their medical and family history, the information they provide would not necessarily ever indicate the presence of the risk, especially if the man had no symptoms of the condition himself or was only a carrier.
Although the provision of fertility treatment is not regulated in the US, guidelines issued by the American Society of Reproductive Medicine (ASRM) state that anonymous gamete donors must provide a family medical history that goes back for at least three generations. The ASRM guidelines also state that full chromosomal screening is not needed where there is a proper family history detailing any potential heritable disorders. Sperm donors are routinely screened for more common genetic disorders, such as cystic fibrosis or sickle cell anaemia, but not for more rare genetic diseases. The cluster of SCN cases was identified by the SCN International Registry and by Dr Laurence Boxer, director of paediatric haematology and oncology at the University of Michigan and an expert on the disease. Although the researchers did not have sperm samples to test, as the clinic had discarded the remainder of the man's sperm, they concluded that the children affected could all be traced back to the sperm of one man because the four couples with affected children all used sperm from the same sperm bank in Michigan, US, and all had the same version of the defective gene. Dr Boxer, who co-authored a report on the findings published in the Journal of Paediatrics, refused to identify the sperm bank by name, or say where the couples treated came from, and stated that it was not known whether the man concerned knew he was a carrier - the sperm bank only reported that the man concerned was 'healthy'. Dr Boxer speculates that as the man was otherwise healthy, he must have had an unusual condition called mosaicism, in which the mutated gene was carried only in his sperm and not in the rest of his body. 'Otherwise he would have been a very sick man', he said.
SCN occurs in only about one in 5 million births - children born with the disease cannot make the type of white blood cell that kills bacteria in the body and, as a result, they are unable to fight infections. The children affected are receiving treatment which helps them to build up their white blood cell production, said Dr Boxer. But he added that they will always have a greater risk of developing leukaemia than other children and all face a 50 per cent chance of passing the condition on to their own children. 'The bottom line is, when you use a sperm donor, you really don't know what you're getting', he said, adding that prospective parents should be advised that screening of donors will not always identify all potential genetic diseases. 'The mothers need to be prepared that there is always an inherent risk of a genetic disorder being transmitted by the donor's sperm', he advised.