An arterial blood gas (ABG) is a blood test that measures the acidity (pH) and the levels of oxygen and carbon dioxide in the blood. Blood for an ABG test is taken from an artery whereas most other blood tests are done on a sample of blood taken from a vein. This test is done to monitor several conditions that can cause serious health complications especially to critically ill individuals.
about 7 years ago
Introduction Hello and welcome! I am finally back to blogging after having a brief hiatus in order to take my final exams. Whilst the trauma is still fresh in my mind, I would like to share with you the top 5 social media tips that helped me through the dark days of undergraduate medicine. Some of you may have already read my old essay on 'How Medical Students should interact with Social Media Networking Sites' and this document deals with some of the problems with professionalism surrounding the use of social media. This blog will not cover such issues, but will instead focus on how you can use social media to benefit your learning/ revision processes. Top Tip 1: YouTube For those of you who are unaware, YouTube is a video-sharing website. Sometimes the site is overlooked as a 'social media' resource but if you consider the simple definition of Social Networking Sites as 'those with user led content,' you can quickly see how YouTube definitely falls into the social media category. It wasn't until I got to University that I realised the potency of YouTube as an educational tool. It has a use at every stage of medical education and it is FREE. If you are still in your pre-clinical training then there are a wealth of videos that depict cellular processes and 3D anatomy - very useful content for the visual learner. For the clinical student, there are a number of OSCE demonstration videos that may be useful in honing your examination skills. There are also a number of presentations on clinical topics that have been uploaded, however, YouTube has no quality control measures for these videos (to my knowledge) so it may be best to subscribe to a more official source if you like to use podcasts/ uploaded presentations for your revision. Another reason YouTube comes in as my number 1 top tip is because I find it difficult to procrastinate whilst using the site. Sure, you can start looking up music and videos that have nothing to do with medicine but personally I find that having a little bit of music on in the background helps me work for longer periods, which is a definite bonus during the revision period. On the other hand, there are many that find YouTube difficult to harness due to the draw of funny videos and favourite Vloggers (Video Bloggers) that can distract the unwary from revision for hours on end. At the end of the day, YouTube was created for funny videos (predominantly of cats it seems) and not for medical education, and this should be kept in mind if you choose to use it as a tool for your learning. Top Tip 2: Facebook Yes, the dreaded Facebook comes in at number two for me. Facebook is by far and away my largest source of procrastination when it comes to writing / working / revising or learning. It is a true devil in disguise, however, there are some very useful features for those who like to work in groups during their revision... For example, during the last six months I have organised a small revision group through Facebook. We set up a 'private page' and each week I would post what topics would be covered in the weeks session. Due to the nature of Facebook, people were obviously able to reply to my posts with suggestions for future topics etc. We were also able to upload photos of useful resources that one or more of us had seen in a tutorial in which the other students hadn't been able to attend. And most importantly, we were able to upload revision notes for each other via the Facebook 'files' tab. This last feature was invaluable for sharing basic notes between a few close colleagues. However, for proper file sharing I strongly recommend the file sharing service 'Dropbox,' which provides free storage for your documents and the ability to access files from any computer or device with internet. Coming back to Facebook, my final thoughts are: if you don't like group work or seeing what your colleagues are doing via their statuses or private messages then it probably isn't a useful resource for you. If you have the motivation (unlike myself) to freeze your Facebook account I can imagine you would end up procrastinating far less (or you'll start procrastinating on something else entirely!). Top Tip 3: Twitter Twitter is a microblogging site. This means that users upload microblogs or 'Tweets' containing useful information they have found on the internet or read in other people's tweets. Twitter's utility as an educational resource is directly related to the 'type' of people you follow. For example, I use Twitter primarily to connect with other people interested in social media, art & medicine and medical education. This means my home screen on twitter is full of people posting about these topics, which I find useful. Alternatively, I could have used my Twitter account to 'follow' all the same friends I 'follow' on Facebook. This would have meant my Twitter home page would have felt like a fast-paced, less detailed version of my Facebook feed just with more hashtags and acronyms - not very useful for finding educational resources. With this in mind, consider setting up two twitter accounts to tease apart the useful tweets about the latest clinical podcast from the useless tweets about what your second cousin once removed just had for lunch. A friend suggested to me that if you really get into twitter it is also possible to use one account and 'group' your followers so that you can see different 'types' of tweets at different times. This seems like a good way to filter the information you are reading, as long as you can figure out how to set up the filters in the first place. Like all Social Media Sites, Twitter gets its fair share of bad press re. online professionalism and its tendency to lure users into hours of procrastination. So again, use with caution. Top Tip 4: Meducation It would not be right to write this blog and not include Meducation in the line-up. Meducation is the first website that I have personally come across where users (students, doctors etc) upload and share information (i.e. the very soul of what social networking is about) that is principally about medicine and nothing else. I'm sure there may be other similar sites out there, but the execution of this site is marvellous and that is what has set it apart from its competitors and lead to its rapid growth (especially over the last two years, whilst i've been aware of the site). When I say 'execution,' I mean the user interface (which is clean and simple), the free resources (giving a taste of the quality of material) and the premium resources (which lecture on a variety of interesting clinical topics rather than sticking to the bread and butter topics 24/7). One of my favourite features of Meducation is the ability to ask 'Questions' to other users. These questions are usually asked by people wishing to improve niche knowledge and so being able to answer a question always feels like a great achievement. Both the questions and answers are mostly always interesting, however the odd question does slip through the net where it appears the person asking the question might have skipped the 'quick google search' phase of working through a tough topic. Meducation harnesses social networking in an environment almost free from professionalism and procrastination issues. Therefore, I cannot critique the site from this angle. Instead, I have decided to highlight the 'Exam Room' feature of the website. The 'Exam Room' lets the user take a 'mock exam' using what I can only assume is a database of questions crafted by the Meducation team themselves (+/- submissions from their user base). However, it is in my opinion that this feature is not up to scratch with the level and volume of questions provided by the competitors in this niche market. I feel wrong making this criticism whilst blogging on Meducation and therefore I will not list or link the competitors I am thinking of here, but they will be available via my unaffiliated blog (Occipital Designs). I hope the Meducation team realise that I make this observation because I feel that with a little work their question database could be improved to the point where it is even better than other sites AND there would also be all the other resources Meducation has to offer. This would make Meducation a truly phenomenal resource. Top Tip 5: Blogging Blogging itself is very useful. Perhaps not necessarily for the learning / revision process but for honing the reflective process. Reflective writing is a large component of undergrad medical education and is disliked by many students for a number of reasons, not least of which is because many find some difficulty in putting their thoughts and feelings on to paper and would much prefer to write with the stiffness and stasis of academic prose. Blogging is great practice for breaking away from essay-writing mode and if you write about something you enjoy you will quickly find you are easily incorporating your own personal thoughts and feelings into your writing (as I have done throughout this blog). This is a very organic form of reflection and I believe it can greatly improve your writing when you come to write those inevitable reflective reports. Conclusion Thanks for reading this blog. I hope I have at least highlighted some yet unharnessed aspects of the sites and resources people already commonly use. Please stay tuned in the next week or two for more on social media in medicine. I am working together with a colleague to produce 'Guidelines for Social Media in Medicine,' in light of the recent material on the subject by the General Medical Council. Please feel free to comment below if you feel you have a Top Tip that I haven't included! LARF Twitter Occipital Designs My Blog As always, any views expressed here are mine alone and are not representative of any organisation. A Worthy Cause... Also, on a separate note: check out Anatomy For Life - a charity medical art auction raising money for organ donation. Main Site Facebook Twitter
Dr. Luke Farmery
about 9 years ago
In a recent article in the BMJ the author wonders about the reasons beyond the rising trend diagnosing Attention Deficit Hyperactivity Disorder (ADHD). The article attempts to infer reasons for this. One possible reason was that the diagnostic criteria especially DSM may seem for some to be more inclusive than ICD-10. The speculation may explain the rise of the diagnosis where DSM is used officially or have an influence. In a rather constructive way, an alternative to rushing to diagnosis is offered and discussed in some details. The tentative deduction that the Diagnostic Statistical Manual (DSM) may be one of the causes of rising diagnosis, due to raising the cut-off of age, and widening the inclusion criteria, as opposed to International Classification of Diseases, 10th revision (ICD-10), captured my attention. On reading the ICD-10 diagnostic criteria for research (DCR) and DSM-5 diagnostic criteria, I found them quite similar in most aspects, even the phraseology that starts with 'Often' in many diagnostic criteria, they seem to differ a bit in age. In a way both classification, are attempting to describe the disorder, however, it sounds as if someone is trying to explain a person's behaviour to you, however, this is not a substitute to direct clinical learning, and observing the behaviour, as if the missing sentence is 'when you see the person, it will be clearer'. El-Islam agrees with the notion that DSM-5 seems to be a bit more inclusive than ICD-10. A colleague of mine who is a child psychiatrist and she is doing her MSc. thesis in ADHD told me, that DSM-5 seems to be a substantial improvement as compared to its predecessor. The criteria - to her - though apparently are more inclusive, they are more descriptive with many examples, and she infers that this will payback in the reliability of the diagnosis. She hopes gene research can yield in biological tests for implicated genes and neurotransmitters in ADHD e.g. DRD4, DAT, gene 5,6,11 etc. One child psychiatrist, regretted the fact that misdiagnosis and under-diagnoses, deprive the patient from one of the most effective treatments in psychiatry. It is hoped the nearest forthcoming diagnostic classification (ICD-11), will address the issue of the diagnosis from a different perspective, or else converge with DSM-5 to provide coherence and a generalised newer standard of practice. The grading of ADHD into mild, moderate, and severe seem to blur the border between disorder and non-disorder, however, this quasi-dimensional approach seems realistic, it does not translate yet directly in differences in treatment approaches as with the case of mild, moderate, severe, and severe depression with psychotic symptoms, or intellectual disability. The author states that one counter argument could be that child psychiatrists are better at diagnosing the disorder. I wonder if this is a reflection of a rising trend of a disorder. If ADHD is compared to catatonia, it is generally agreed that catatonia is less diagnosed now, may be the epidemiology of ADHD is not artefact, and that we may need to look beyond the diagnosis to learn for example from environmental factors. Another issue is that there seems to be significant epidemiological differences in the rates of diagnosis across cultures. This may give rise to whether ADHD can be classified as a culture-bound syndrome, or whether it is influenced by culture like anorexia nervosa, or it may be just because of the raising awareness to such disorders. Historically, it is difficult to attempt to pinpoint what would be the closest predecessor to ADHD. For schizophrenia and mania, older terms may have included insanity, for depression it was probably melancholia, there are other terms that still reside in contemporary culture e.g. hypochondriasis, hysteria, paranoia etc. Though, it would be too simplistic to believe that what is meant by these terms was exactly what ancient cultures meant by them, but, they are not too far. ADHD seems to lack such historical underpinning. Crichton described a disorder he refers to as 'mental restlessness'. Still who is most often credited with the first description of ADHD, in his 1902 address to the Royal College of Physicians. Still describes a number of patients with problems in self-regulation or, as he then termed it, 'moral control' (De Zeeuw et al, 2011). The costs and the risks related to over-diagnosis, ring a warning bell, to enhance scrutiny in the diagnosis, due to subsequent stigma, costs, and lowered societal expectations. They all seem to stem from the consequences of the methodology of diagnosis. The article touches in an important part in the psychiatric diagnosis, and classifications, which is the subjective nature of disorders. The enormous effort done in DSM-5 & ICD-10 reflect the best available evidence, but in order to eliminate the subjective nature of illness, a biological test seems to be the only definitive answer, to ADHD in particular and psychiatry in general. Given that ADHD is an illness and that it is a homogeneous thing; developments in gene studies would seem to hold the key to understanding our current status of diagnosis. The suggested approach for using psychosocial interventions and then administering treatment after making sure that it is a must, seems quite reasonable. El-Islam, agrees that in ADHD caution prior to giving treatment is a recommended course of action. Another consultant child psychiatrist mentioned that one hour might not be enough to reach a comfortable diagnosis of ADHD. It may take up to 90 minutes, to become confident in a clinical diagnosis, in addition to commonly used rating scales. Though on the other hand, families and carers may hypothetically raise the issue of time urgency due to scholastic pressure. In a discussion with Dr Hend Badawy, a colleague child psychiatrist; she stated the following with regards to her own experience, and her opinion about the article. The following is written with her consent. 'ADHD is a clinically based diagnosis that has three core symptoms, inattention, hyperactivity and impulsivity in - at least - two settings. The risk of over-diagnosis in ADHD is one of the potentially problematic, however, the risk of over-diagnosis is not confined to ADHD, it can be present in other psychiatric diagnoses, as they rely on subjective experience of the patient and doctor's interviewing skills. In ADHD in particular the risk of under-diagnosis is even more problematic. An undiagnosed child who has ADHD may suffer various complications as moral stigma of 'lack of conduct' due to impuslivity and hyperactivity, poor scholastic achievement, potential alienation, ostracization and even exclusion by peer due to perceived 'difference', consequent feelings of low self esteem and potential revengeful attitude on the side of the child. An end result, would be development of substance use disorders, or involvement in dissocial behaviours. The answer to the problem of over-diagnosis/under-diagnosis can be helped by an initial step of raising public awareness of people about ADHD, including campaigns to families, carers, teachers and general practitioners. These campaigns would help people identify children with possible ADHD. The only risk is that child psychiatrists may be met with children who their parents believe they might have the disorder while they do not. In a way, raising awareness can serve as a sensitive laboratory investigation. The next step is that the child psychiatrist should scrutinise children carefully. The risk of over-diagnosis can be limited via routine using of checklists, to make sure that the practice is standardised and that every child was diagnosed properly according to the diagnostic criteria. The use of proper scales as Strengths and Difficulties Questionnaire (SDQ) in its two forms (for parents SDQ-P and for teachers SDQ-T) which enables the assessor to learn about the behaviour of the child in two different settings. Conner's scale can help give better understanding of the magnitude of the problem. Though some people may voice criticism as they are mainly filled out by parents and teachers, they are the best tools available at hands. Training on diagnosis, regular auditing and restricting doctors to a standard practice of ensuring that the child and carer have been interviewed thoroughly can help minimise the risk of over-diagnosis. The issue does not stop by diagnosis, follow-up can give a clue whether the child is improving on the management plan or not. The effects and side effects of treatments as methylphenidate should be monitored regularly, including regular measurement height and weight, paying attention to nausea, poor appetite, and even the rare side effects which are usually missed. More restrictions and supervision on the medication may have an indirect effect on enhancing the diagnostic assessment. To summarise, the public advocacy does not increase the risk of over-diagnosis, as asking about suicidal ideas does not increase its risk. The awareness may help people learn more and empower them and will lead to more acceptance of the diagnosed child in the community. Even the potential risk of having more case loads for doctors to assess for ADHD may help give more exposure of cases, and reaching more meaningful epidemiological finding. From my experience, it is quite unlikely to have marked over-representation of children who the families suspect ADHD without sufficient evidence. ADHD remains a clinical diagnosis, and it is unlikely that it will be replaced by a biological marker or an imaging test in the near future. After all, even if there will be objective diagnostic tests, without clinical diagnostic interviewing their value will be doubtful. It is ironic that the two most effective treatments in psychiatry methylphenidate and Electroconvulsive Therapy (ECT) are the two most controversial treatments. May be because both were used prior to having a full understanding of their mechanism of action, may be because, on the outset both seem unusual, electricity through the head, and a stimulant for hyperactive children. Authored by E. Sidhom, H. Badawy DISCLAIMER The original post is on The BMJ doc2doc website at http://doc2doc.bmj.com/blogs/clinicalblog/#plckblogpage=BlogPost&plckpostid=Blog%3A15d27772-5908-4452-9411-8eef67833d66Post%3Acb6e5828-8280-4989-9128-d41789ed76ee BMJ Article: (http://www.bmj.com/content/347/bmj.f6172). Bibliography Badawy, H., personal communication, 2013 El-Islam, M.F., personal communication, 2013 Thomas R, Mitchell GK, B.L., Attention-deficit/hyperactivity disorder: are we helping or harming?, British Medical Journal, 2013, Vol. 5(347) De Zeeuw P., Mandl R.C.W., Hulshoff-Pol H.E., et al., Decreased frontostriatal microstructural organization in ADHD. Human Brain Mapping. DOI: 10.1002/hbm.21335, 2011) Diagnostic Statistical Manual 5, American Psychiatric Association, 2013 Diagnostic Statistical Manual-IV, American Psychiatric Association, 1994 International Classification of Diseases, World Health Organization, 1992
Dr Emad Sidhom
over 8 years ago
Metabolic syndrome and obesity are attaining epidemic proportions worldwide. This PPT shows the link between the two, their aetiology, the pathophysiology and what simple measures could be used in managing the conditions.
over 9 years ago
The human brain is the main organ of the human central nervous system. It is located in the head, protected by the skull. It has the same general structure as the brains of other mammals, but with a more developed cerebral cortex. Large animals such as whales and elephants have larger brains in absolute terms, but when measured using a measure of relative brain size, which compensates for body size, the quotient for the human brain is almost twice as large as that of a bottlenose dolphin, and three times as large as that of a chimpanzee, though the quotient for a treeshrew's brain is larger than that of a human's. Much of the size of the human brain comes from the cerebral cortex, especially the frontal lobes, which are associated with executive functions such as self-control, planning, reasoning, and abstract thought. The area of the cerebral cortex devoted to vision, the visual cortex, is also greatly enlarged in humans compared to other animals.
over 6 years ago
For the last years, the wearable health trackers' revolution has been going on. There are gadgets and devices with which we can measure health parameters and vital signs at home. But what comes after that?
about 7 years ago
Professor Saltzman continues his description of nephron anatomy, and the specific role of each part of the nephron in establishing concentration gradients to help in secretion and reabsorption of water, ions, nutrients and wastes. A number of molecular transport processes that produces urine from the initial ultra-filtrate, such as passive diffusion by concentration difference, osmosis, and active transport with sodium-potassium ATPase, are listed. Next, Professor Saltzman describes a method to measure glomerular filtration rate (GFR) using tracer molecule, inulin. He then talks about regulation of sodium, an important ion for cell signaling in the body, as an example to demonstrate the different ways in which nephrons maintain homeostasis.
over 8 years ago
Relative risk, relative and absolute risk reduction, number needed to treat and confidence intervals - Smart Health Choices - NCBI Bookshelf
How do you interpret the results of a randomised controlled trial? A common measure of a treatment is to look at the frequency of bad outcomes of a disease in the group being treated compared with those who were not treated. For instance, supposing that a well-designed randomised controlled trial in children with a particular disease found that 20 per cent of the control group developed bad outcomes, compared with only 12 per cent of those receiving treatment. Should you agree to give this treatment to your child? Without knowing more about the adverse effects of the therapy, it appears to reduce some of the bad outcomes of the disease. But is its effect meaningful?
almost 7 years ago
This month’s case is by David R Bell PhD, co-author of Medical Physiology: Principles for Clinical Medicine, 3e (ISBN: 9781451110395) For more information, or to purchase your copy, visit: http://tiny.cc/Rhoades4e, with 15% off using the discount code: MEDUCATION. The case below is followed by a quiz question, allowing you a choice of diagnoses. Select the one letter section that best describes the patient’s condition. The Case A 28-year old woman has an unremarkable pregnancy through her first 28 weeks of gestation, with normal weight gain and no serious complications. She has no previous history of diabetes, hypertension of other systemic disease before or during her current pregnancy. During her 30-week checkup, her blood pressure measures 128/85, and she complains about feeling slightly more “bloated” than usual with swelling in her legs that seems to get more uncomfortable as the day goes on. Her obsterician recommends that she get more bed rest, stay off her feet as much as possible and return for evaluation in one week. At the one-week follow-up, the patient presents with noticable”puffiness” in her face, and a blood pressure of 145/95. She complains she has been developing headaches, sporadic blurred vision, right-sided discomfort and some shortness of breath. She has gained more than 10 lb (4.5kg) in the past week. A urinalysis on the patient revelas no glucose but a 3+ reading for protein. Her obstetrician decides to admit her immediately to a local tertiary care hospital for further evaluation. Over the next 24 hours, the patient’s urine output is recorded as 500mL and contains 6.8 grams of protein. Her plasma albumin level is 3.1 g/dl, hemacrit 48%, indirect bilirubin 1.5mg/dl and blood platelets=77000/uL, respectively. Her blood pressure is now 190/100. It is decided to try to deliver the foetus. The expelled placenta is small and shows signs of widespread ischmic damage. Within a week of delivery, the mother’s blood pressure returns to normal, and her oedema subsides. One month later, the mother shows no ill effects of thos later-term syndrome. Question What is the clinical diagnosis of this patient’s condition and its underlying pathophysiology? A. Gestational Hypertension B. Preeclampsia C. Gestational Diabetes D. Compression of the Inferior Vena Cava Answer The correct answer is "B. Preeclampsia". The patient’s symptoms and laboratory findings are consistent with a diagnosis of Preeclampsia, which is a condition occurring in some pregnancies that causes life-threatening organ and whole body regulatory malfunctions. The patient’s negative urine glucose is inconsistent with gestational diabetes. Gestational hypertension or vena caval compression cannot explain all of the patient findings. The patient has three major abnormal findings- generalised oedema, hypertension and proteinuria which are all common in preeclampsia. Although sequalae of a normal pregnancy can include water and salt retention, bloating, modest hypertension and leg swelling (secondary to capillary fluid loss from increased lower limb capillary hydrostatic pressure due to compression of the inferior vena cava by the growing foetus/uterus), oedema in the head and upper extremities, a rapid 10 pound weight gain and shortness of breath suggests a generalized and serious oedematous state. The patient did not have hypertension before or within 20 weeks gestation (primary hypertension) and did not develop hypertension after the 20th week of pregnancy with no other abnormal findings (gestational hypertension). Hypertension with proteinuria occurring beyond the 20th week of pregnancy however is a hallmark of preeclampsia. In addition, the patient has hemolysis (elevated bilirubin and LDH levels), elevated liver enzyme levels and thrombocytopenia. This is called the HELLP syndrome (HELLP = Hemolysis, Elevated Liver enzymes and Low Platelets.), and is considered evidence of serious patient deterioration in preeclampsia. A urine output of 500 ml in 24 hours is 1/2 to 1/4 of normal output in a hydrated female and indicates renal insufficiency. Protein should never be found in the urine and indicates loss of capillaries integrity in glomeruli which normally are not permeable to proteins. The patient has substantial 24 urine protein loss and hypoalbuminemia. However, generally plasma albumin levels must drop below 2.5 gm/dl to decrease plasma oncotic pressure enough to cause general oedema. The patient’s total urinary protein loss was insufficient in this regard. Capillary hyperpermeability occurs with preeclampsia and, along with hypertension, could facilitate capillary water efflux and generalized oedema. However myogenic constriction of pre-capillary arterioles could reduce the effect of high blood pressure on capillary water efflux. An early increase in hematocrit in this patient suggests hemoconcentration which could be caused by capillary fluid loss but the patient’s value of 48 is unremarkable and of little diagnostic value because increased hematocrit occurs in both preeclampsia and normal pregnancy. PGI2, PGE2 and NO, produced during normal pregnancy, cause vasorelaxation and luminal expansion of uterine arteries, which supports placental blood flow and development. Current theory suggests that over production of endothelin, thromboxane and oxygen radicals in preeclampsia antagonize vasorelaxation while stimulating platelet aggregation, microthrombi formation and endothelial destruction. These could cause oedema, hypertension, renal/hepatic deterioration and placental ischemia with release of vasotoxic factors. The patient’s right-sided pain is consistent with liver pathology (secondary to hepatic DIC or oedematous distention). Severe hypertension in preeclampsia can lead to maternal end organ damage, stroke, and death. Oedematous distension of the liver can cause hepatic rupture and internal hemorrhagic shock. Having this patient carry the baby to term markedly risks the life of the mother and is not considered current acceptable clinical practice. Delivery of the foetus and termination of the pregnancy is the only certain way to end preeclampsia. Read more This case is by David R Bell PhD, co-author of Medical Physiology: Principles for Clinical Medicine, 3e (ISBN: 9781451110395) For more information, or to purchase your copy, visit: http://tiny.cc/Rhoades4e. Save 15% (and get free P&P) on this, and a whole host of other LWW titles at (lww.co.uk)[http://lww.co.uk] when you use the code MEDUCATION when you check out! About LWW/ Wolters Kluwer Health Lippincott Williams and Wilkins (LWW) is a leading publisher of high-quality content for students and practitioners in medical and related fields. Their text and review products, eBooks, mobile apps and online solutions support students, educators, and instiutions throughout the professional’s career. LWW are proud to partner with Meducation.
Lippincott Williams & Wilkins
about 9 years ago
This is an excerpt from "Fluids and Electrolytes Made Incredibly Easy! 1st UK Edition" by William N. Scott. For more information, or to purchase your copy, visit: http://tiny.cc/Fande. Save 15% (and get free P&P) on this, and a whole host of other LWW titles at lww.co.uk when you use the code MEDUCATION when you check out! Introduction The chemical reactions that sustain life depend on a delicate balance – or homeostasis – between acids and bases in the body. Even a slight imbalance can profoundly affect metabolism and essential body functions. Several conditions, such as infection or trauma, and certain medications can affect acid-base balance. However, to understand this balance, you need to understand some basic chemistry. Understanding pH Understanding acids and bases requires an understanding of pH, a calculation based on the concentration of hydrogen ions in a solution. It may also be defi ned as the amount of acid or base within a solution. Acids consist of molecules that can give up, or donate, hydrogen ions to other molecules. Carbonic acid is an acid that occurs naturally in the body. Bases consist of molecules that can accept hydrogen ions; bicarbonate is one example of a base. A solution that contains more base than acid has fewer hydrogen ions, so it has a higher pH. A solution with a pH above 7 is a base, or alkaline. A solution that contains more acid than base has more hydrogen ions, so it has a lower pH. A solution with a pH below 7 is an acid, or acidotic. Getting your PhD in pH A patient’s acid-base balance can be assessed if the pH of their blood is known. Because arterial blood is usually used to measure pH, this discussion focuses on arterial samples. Arterial blood is normally slightly alkaline, ranging from 7.35 to 7.45. A pH level within that range represents a balance between the concentration of hydrogen ions and bicarbonate ions. The pH of blood is generally maintained in a ratio of 20 parts bicarbonate to 1 part carbonic acid. A pH below 6.8 or above 7.8 is usually fatal. Too low Under certain conditions, the pH of arterial blood may deviate significantly from its normal narrow range. If the blood’s hydrogen ion concentration increases or bicarbonate level decreases, pH may decrease. In either case, a decrease in pH below 7.35 signals acidosis. Too high If the blood’s bicarbonate level increases or hydrogen ion concentration decreases, pH may rise. In either case, an increase in pH above 7.45 signals alkalosis. Regulating acids and bases A person’s well-being depends on their ability to maintain a normal pH. A deviation in pH can compromise essential body processes, including electrolyte balance, activity of critical enzymes, muscle contraction and basic cellular function. The body normally maintains pH within a narrow range by carefully balancing acidic and alkaline elements. When one aspect of that balancing act breaks down, the body can’t maintain a healthy pH as easily, and problems arise.
Lippincott Williams & Wilkins
about 9 years ago
Shattered. Third consecutive day of on-calls at the birth centre. I’m afraid I have little to show for it. The logbook hangs limply at my side, the pages where my name is printed await signatures; surrogate markers of new found skills. Half asleep I slump against the wall and cast my mind back to the peripheral attachment from which I have not long returned. The old-school consultant’s mutterings are still fresh: “Medical education was different back then you see....you are dealt a tough hand nowadays.” I quite agree, it is Saturday. Might it be said the clinical apprenticeship we know today is a shadow of its former self? Medical school was more a way of life, students lived in the hospital, they even had their laundry done for them. Incredulous, I could scarcely restrain a chuckle at the consultant’s stories of delivering babies while merely a student and how the dishing out of “character building” grillings by their seniors was de rigeur. Seldom am I plied with any such questions. Teaching is a rare commodity at times. Hours on a busy ward can bear little return. Frequently do I hear students barely a rotation into their clinical years, bemoan a woeful lack of attention. All recollection of the starry-eyed second year, romanced by anything remotely clinical, has evaporated like the morning dew. “Make way, make way!...” cries a thin voice from the far reaches of the centre. A squeal of bed wheels. The newly crowned obs & gynae reg drives past the midwife station executing an impressive Tokyo drift into the corridor where I stand. Through the theatre doors opposite me he vanishes. I follow. Major postpartum haemorrhage. A bevy of scrubs flit across the room in a live performance of the RCOG guidelines for obstetric haemorrhage. They resuscitate the women on the table, her clammy body flat across the carmine blotched sheets. ABC, intravenous access and a rapid two litres of Hartmann’s later, the bleeding can not be arrested by rubbing up contraction. Pharmacological measures: syntocinon and ergometrine preparations do not staunch the flow. Blood pressure still falling, I watch the consciousness slowly ebb from the woman’s eyes. Then in a tone of voice, seemingly beyond his years, the reversely gowned anaesthetist clocks my badge and says, “Fetch me the carboprost.” I could feel an exercise in futility sprout as I gave an empty but ingratiating nod. “It’s hemabate....in the fridge” he continues. In the anaesthetic room I find the fridge and rummage blindly through. Thirty seconds later having discovered nothing but my general inadequacy, I crawl back into theatre. I was as good as useless though to my surprise the anaesthetist disappeared and returned with a vial. Handing me both it and a prepped syringe, he instructs me to inject intramuscularly into the woman’s thigh. The most common cause of postpartum haemorrhage is uterine atony. Prostaglandin analogues like carboprost promote coordinated contractions of the body of the pregnant uterus. Constriction of the vessels by myometrial fibres within the uterine walls achieves postpartum haemostasis. This textbook definition does not quite echo my thoughts as I gingerly approach the operating table. Alarmingly I am unaware that aside from the usual side effects of the drug in my syringe; the nausea and vomiting, should the needle stray into a nearby vessel and its contents escape into the circulation, cardiovascular collapse might be the unfortunate result. Suddenly the anaesthetist’s dour expression as I inject now assumes some meaning. What a relief to see the woman’s vitals begin to stabilise. As we wheel her into the recovery bay, the anaesthetist unleashes an onslaught of questions. Keen to redeem some lost pride, I can to varying degrees, resurrect long buried preclinical knowledge: basic pharmacology, transfusion-related complications, the importance of fresh frozen plasma. Although, the final threat of drawing the clotting cascade from memory is a challenge too far. Before long I am already being demonstrated the techniques of regional analgesia, why you should always aspirate before injecting lidocaine and thrust headlong into managing the most common adverse effects of epidurals. To have thought I had been ready to retire home early on this Saturday morning had serendipity not played its part. A little persistence would have been just as effective. It’s the quality so easily overlooked in these apparently austere times of medical education. And not a single logbook signature gained. Oh the shame! This blog post is a reproduction of an article published in the Medical Student Newspaper, February 2014 issue.
over 8 years ago
infection control measures in IV therapy
about 7 years ago
A government policy designed to reduce the regulatory burden on business is making it increasingly difficult to introduce measures to improve public health in the United Kingdom, such as steering people away from unhealthy foods, a group of medical bodies and charities has warned.
almost 7 years ago
Much of the follow-up of pregnant women is carried out in the community, by midwifes at primary health care centres. The risk of death from pregnancy in the UK is roughly 1 in 20 000. Antenatal care is as much about educating women about pregnancy, childbirth and child care, as it is about providing for actual medical needs, particularly in the case of a first pregnancy. The exact measures will differ between NHS trusts, but below is a general outline of the type of care provided in pregnancy.
almostadoctor.com - free medical student revision notes
about 8 years ago
Lung compliance is the ability of the lungs to expand. Elastance measures the work that has to be exerted by the muscles of inspiration to expand the lungs. Factors affecting these are discussed here.
about 8 years ago
It's been a while since I've added any thoughts to this blog. In that time I have finished my Obs/Gynae placement, I have spent a week on labour ward, and done my first week of my 4th year surgical placement. All the while cramming in revision between various activities and general staying alive measures. This, I feel, is how most people who are sitting their final written exams are spending their time, so I don't feel so alone. I just want to bring to the attention one amazing incident that happened on my labour ward week. I was on a night shift, there wasn't a lot going on. Absolutely everyone was knackered, the registrar who'd been on nights for the past week was just chatting to me. I have never seen someone look so tired. The emergency alarm went off and a lady had a cord prolapse, which is an obstetric emergency with a high foetal mortality rate. Now I think it's amazing that the doctor went from nearly falling asleep to switched on 'surgical-mode' in an instant, successfully performed the C-section, delivering the baby in about a minute, then went back to being absolutely knackered and let the SHO close up the wound. It just really impressed me and I felt it was something worth sharing. Actually I was incredibly surprised that I enjoyed Obs/Gynae. Women's health was a placement I was dreading, it was my last major knowledge gap and I didn't have a clue what it was going to be like. If my tutor for the block does read this, thank you for all your help and getting me involved in everything. I would encourage other students who are going into it and feeling any level of apprehension to just throw yourselves into it and give 110% effort. It is a great placement for practicing transferable skills (this is important to remember, especially if you don't have any desire to go into it you CAN transfer and practice skills from elsewhere!) and getting heavily involved in patient care. Also I'd like to point out the Mother and Baby were fine :)
about 9 years ago