By M. Fabio. Dallas Baptist University.
None of the other antibodies are consistent with the screen results (Answers A buy 10 mg toradol, B 10mg toradol free shipping, C buy toradol 10mg otc, and E). Antibodies in the Lutheran system are generally not considered clinically signifcant. If a Lutheran antibody is associated with a hemolytic transfusion reaction, the reaction is generally mild. Lutheran antigens demonstrate variable strength observed in serologic testing, which accounts for the characteristic mixed-feld agglutination patterns observed. Lutheran antigens are present on blood vessels and tissues including brain, heart, kidney, liver, lung, placenta, pancreas, atrial wall, tongue, trachea, skin, skeletal muscle, cervix, ileum, colon, stomach, and gall bladder, but are not present on lymphocytes, granulocytes, monocytes and platelets. The antigens are detected on fetal cells at 10–12 weeks gestation and are poorly developed at birth. Answer: B—Lutheran antibodies are adsorbed by the Lutheran antigens present on the placenta and Lutheran antigens are only weakly expressed on cord cells. Lutheran antigens are able to stimulate IgG clinically signifcant antibodies, evidenced in a mild to moderate transfusion reactions which have been documented in the literature. The most common phenotype in the Duffy blood group system in the Caucasian population is which of the following? The system is made up of two common antigens which result in the common phenotypes of Fy(a+b−)/ in 20% of the Caucasian population, Fy(a+b+) in 48% of the Caucasian population and Fy(a−b+) in 32% of the Caucasian population. A null expression Fy(a−b−) is associated with black phenotypes with up to 67%–70% of African Americans lacking the Duffy antigens. Answer: B—Although Fy(a−b−) is the most common phenotype in the African/Black population (Answer D), the Fy(a+b+) phenotype is most common in the European/white populations (83%). Fy(a+b−) (Answer C) is the second most common phenotype in the Caucasian population. Fy(a−b−) x phenotypes (Answer D) are most common in individuals of African descent. The Fy (Answer E) allele correlates with an unusual weak expression of Fy antigen in a Caucasian. Of the following phenotypes, the most common among individuals of African ancestry is which of the following? Jk(a+) phenotypes are found in 91% of African/Black populations while only 77% of the European/Caucasian population. Another example is Jk(b−) phenotype is found in 57% of African/Black population while only 28% of the European/ Caucasian Anti-Jk3 made to a high prevalence antigen is produced by individuals who are Jk(a−b−) phenotype. This expression is more prevalent in Philippino, Polynesian, Chinese, Japanese, and Indonesian populations. The rare Jk(a−b−) (Answer D) phenotype is associated with Pacifc islander, Japanese and Chinese populations. None of the other choices (Answers B, C, and E) are correct for this ethnic group. Studies by Peter Agre on aquaporin-1 lead to the discovery of the frst water transporter in man and only the second Nobel Prize in Transfusion Medicine. The Colton blood group system is made up of four a b a b antigens (Co , Co , Co3, and Co4). These antigens are one antithetical pair (Co and Co ) and two a b high incidence antigens (Co3 and Co4). In a application, the majority of the population would be incompatible with a patient who has anti-Co b (99. On the other hand if a patient has an antibody to a low prevalence antigen, such as Co , most of the population will be compatible. In addition, they are able to cause severe hemolytic disease of the fetus and newborn. None of the other choices (Answers B, C, D, and E) are correct based on the information above. Anti-Yt is identifed in a 72-year-old male and the attending physician wants to transfuse urgently. Since anti-Yt is an antibody to a high prevalence antigen, the majority of the population will be incompatible with the patient’s sample. However, rare Yt(a−) red blood cell units may be difficult to find locally and may require a search with the national rare donor registry. However, the clinical signifcance of the antibody is unknown without further advanced testing, such as antibody subclass testing, Monocyte Monolayer Assay, or chromium labeled studies. It may be helpful to know the IgG subclass (Answer C), but this will not provide information to determine clinical 51 signifcance. The Cr (Answer B) red cell survival studies are rarely performed to assess antibody signifcance and given the urgency would not be completed for this type of antibody of variable clinical signifcance. One would only need Yt(a−) donor units through a national search (Answer D) if the patient’s antibody has demonstrated decreased red cell survival in previous analysis. The family (Answer E) is a possibility for compatible donors, but in the scenario provided this is an urgent provision of blood. There is not time for screening, collection, and provision of dedicated donors for this patient. What type of antigenic determinant and antibody class is most likely present in the given antibody detection (screen) results below? Protein type blood group antibodies, such as Rh, Kell, Duffy, or Kidd are typically IgG in nature. These antibodies are not generally naturally occurring, but stimulated by red cell exposure from transfusion, transplantation, and/or pregnancy. The Transfusion Service chooses red cell donor units which lack the specifcity that is detected to prevent acute and/or delayed hemolysis in the presence of the IgG antibody. Answer: D—The antibody detection test (screen) is non-reactive at immediate spin; therefore, there is not an IgM directed to carbohydrate blood group (Answers A and E) specifcity detected. Protein blood group system antibodies are more likely to be IgG, whereas carbohydrate blood group antibodies are likely to be IgM (Answer B). An antibody identifcation panel showed similar results (weak + to 2+ positive) with all panel cells tested. A sample was sent to the Immunohematology Reference a Laboratory and an anti-McC was identifed. These IgG antibodies can be of high titer, >16 and are of low avidity, showing weak, variable reactivity (Table 6. Antibodies to antigens in these systems are typically considered clinically insignifcant. They do not cause hemolytic transfusion reactions or hemolytic disease of the fetus or newborn. Given the high frequency of the antigens virtually all crossmatches will be incompatible.
It is important to note that obtaining an unbiased sample in any research study is very diffcult order 10 mg toradol free shipping. A questionnaire might be sent to a random sample of the population purchase toradol 10 mg otc, but unless there is a 100 per cent response rate generic toradol 10mg without prescription, the responses obtained will be biased. Contrast this with random allocation; which is where the sample is not ran- dom but participants within a non random sample (for example a conve- nience sample) are allocated at random into one group or another. Experimental methods can be used to measure the effectiveness of an inter- vention (for example, smoking cessation interventions). In this case, quanti- tative methods could be used to compare how many people give up smoking in the intervention group and in the non-intervention group. The important thing here is that the experimenter controls who has what intervention. There are non-experimental research designs, such as questionnaires/ surveys in which participants respond to questions. Their responses can then be counted numerically – for example 30 per cent of those who responded to the survey had done X. In principle quantitative research is generally undertaken when you are looking to measure something and that something is suitable for numerical 60 What are the different types of research? Let’s look in more detail at some of the quantitative research designs that you are likely to encounter. Randomized Controlled Trials Randomized controlled trials are a form of clinical trial, or scientifc pro- cedure used to determine the effectiveness of a treatment, intervention or medicine. This practice was (and is) necessary to protect babies from the severe cold and as a means experimental and non-experimental quantitative research 61 of keeping babies safe during travel. However as times developed and differ- ent options became available for protecting children, the question of whether the practice of swaddling is harmful to babies has become signifcant. The researchers described the trial: 1279 healthy new-borns in Ulaanbaatar, Mongolia, were allocated at birth to traditional swaddling or non-swaddling. The families received 7 months of home visits to collect data and monitor compliance. In the above example, the intervention investigated was the introduction of clothing and the control group was the standard practice of swaddling newborn babies. The importance of randomization Participants are allocated into the different treatment groups of the trial at random. This ensures that participants are allocated into the different groups by chance rather than by the preference of the patient/client or researcher. It is very important that neither the partici- pant nor the researcher has any control over the group to which a participant is allocated. If we take the Mongolian study, the process of randomization required that mothers of the babies did not have any input into which group their babies were entered into. One group were allocated to the traditional practice of swaddling whilst the other group were given extra warm layers of clothing. It must have been quite daunting for the mothers of the babies in the inter- vention group who were not swaddled but were dressed in extra layers of clothing, to go against years of traditional practice! When they agreed to par- ticipate in the study, they were informed that their baby could be allocated to either of the two groups. This is because the researcher is looking for differences between the treatment group 62 What are the different types of research? If the groups are random, then any differences in out- come can be said to be due to the intervention. This can only be determined if the different groups, which are commonly referred to as ‘arms’, of the trial are essentially equal in all respects except for the treatment given. The researcher is looking for differences between the different groups of the trial that can be attributed to the intervention. In the case of the Mongolian babies, researchers were looking to see if the practice of swaddling had any effect on the babies’ development, when this group of babies were compared to babies who had not been swaddled. Without equal groups, it is not be possible to determine whether the differ- ences in outcomes observed between the different treatment or control groups of the trial were due to the intervention or whether they were due to the dif- ferences in the characteristics of the participants who had self-selected into one group or another. If it is particularly important that participants with specifc characteristics are equally represented in both groups (for example, those in certain age groups or those who care for relatives might have different lifestyle habits from those without children and you might want an equal number of these participants in each group) then a further form of randomization can be used. This is an additional statistical process that assists in ensuring that the groups are equal in respect of certain predefned criteria (for example age, sex, or smoker) that are relevant for the research, and it is called stratifcation or minimization. Once each treatment group in the trial has been randomly allocated, the groups are considered to be equal, and the intervention, treatment or therapy is given to the frst group. The second group receives either the standard treatment (or no treatment or placebo, depending on the individual study design). The groups are then observed and the differences between the groups are monitored. Given that the two groups of participants were randomly allocated and hence can be considered to be ‘equal’, any difference between the groups can be attributed to the effect of the intervention. The outcome measured is often called the ‘dependent variable’ The non-intervention group may be: • A control group who receive the established standard treatment or inter- vention (while the intervention group receive the new treatment/intervention). If at all possible, neither the researcher running the trial nor the participants know which group they have been allocated to. A placebo group is however only ethical if non-treatment is not thought to be harmful to participants – let’s say if there was genuine uncertainty as to the effectiveness of a treatment. This is called blinding and a study can either be double blind – when neither the researcher nor participants know which group the participants are in, or single blind – when the researchers only know which group the par- ticipants are in. This obviously depends on what the study is looking for and whether it is possible to blind either the researchers or participants. In the Mongolian study, there was a control group, who were the group of babies given the traditional practice of swaddling. At the end of the trial, researchers look to see what the differences in outcome are between the different groups in the trial – for example, what was the difference in growth and development between the babies who had been swaddled and those who had not? Because the groups were otherwise equal, we can say that any difference in outcome is likely to be attributable to the intervention versus control (clothing versus swaddling). The null hypoth- esis is a starting point – it is a ‘negatively’ phrased statement that asserts that there is no difference between the two groups. If the results show that there is a difference between the control group and the intervention group, then the null hypothesis can be rejected. Mothers of the babies who agreed to participate in the study were informed about the process of randomization. This population was then randomly allocated into two groups: 1 Group One babies carry on normal swaddling practice. The rate and range of movement and overall development of the babies in the different groups is then compared at set points in the study. Any differences in outcomes are attributed to the swaddling or non-swaddling, given that the groups were random- ized and therefore otherwise equal. In the Mongolian study, the researchers found that there were no differences in the growth and development of the babies in either group.
Tetralogy of tomatic until later in life cheap 10 mg toradol with amex, constituting an indication for Fallot manifests cyanosis early on 10 mg toradol otc, as there is a right to left balloon valvuloplasty and occasionally valve replacement 10mg toradol, shunt from the beginning. Aortic stenosis, 75% of which cases are space near the left sternal border, and is characterized by a of the valvular type, do not become symptomatic until fixed split second sound. The murmur radiates a continuous murmur that is loudest in systole (the to the carotids. It its a systolic ejection murmur, loudest along the lower left does not make an appearance until about 2 years of age. This can lead to the use of intravenous indomethacin if they do not spon- pulmonary hypertension, the more likely the larger the taneously close within the first 2 days with supportive defect. Radiation of a systolic murmur to a common physiologic murmur in children and can be the left axilla is virtually pathognomonic of mitral insuf- heard in conjunction with a still murmur. The murmur of aortic stenosis is loud and harsh, murmurs that occur within the first 2 days of life, transi- both at the base and at the left sternal border, and radiates tional murmurs, a nonspecific term for benign and tran- to the carotids. There may be palpable thrills in the sient functional murmurs often present in newborns suprasternal notch, the right base (point of S2), and over within minutes to hours (but not at the moment) of birth, the carotid arteries. A patent ductus is necessary along with the transposition to allow any oxygenated blood to reach the 12. Without either a patent ductus or the fingernails will not be observed in coarctation. Male other pathway for shunting of oxygenated blood into the individuals are significantly more often affected than left side of the heart, the condition is incompatible with female individuals. Cardio- characterized by a shunt and therefore is not associated vascular diseases. Current Pediatric Diagnosis and Treatment, male to female infants 3:1 and tends to occur in larger than 19th ed. Repair through reversal of the great vessels surgically must occur within the first 7 days. This has occurred despite the patient’s com- pliance with your prescribed no-salt-added diet. He has a ulants” includes clonidine, methyldopa, and many oth- family history of deaths by stroke and renal failure. Each of the following is true about this classification Which of the following may be the single most propi- except for which one? How- (D) Beta-adrenergic blockade works well in ever, therapeutic targets vary with special circum- conjunction with alpha stimulants2 stances. She denies diar- 9 A 75-year-old woman is seeing you for the first time; rhea, vomiting, past or present fistulae or enterostomy, it is the first time she has seen any doctor for the past or taking any prescription medications. You decide (B) Essential hypertension of the salt-retentive type that her isolated systolic hypertension should be treated (C) Pheochromocytoma with a pharmaceutical agent. Which of the following (D) Primary aldosteronism would be the best first-line drug? In discussion of his renal function, you must (A) Patients with paroxysms of anxiety are often teach the patient what he must do to retard the accel- tested for pheochromocytoma erated reduction of renal function. Which of the following may be helpful in (B) 130/85 further elucidating the diagnosis? Hydrochlorthiazide does not reduce tion supports the theme, as diuretic responsive hyperten- insulin resistance. Hctz is a distal loop diuretic, which is a tensive, respond to diuretics, particularly thiazides. All quite serviceable antihypertensive, tending to function others respond to the other drugs to varying degrees, thereby in people who have a tendency to retain salt and often in combination with the other classes mentioned. Furosemide, as a proximal loop of responding to a simple diuretic, such as hydrochlorthi- diuretic, does not normally have an antihypertensive azide, generally compounded with triampterene or pharmacologic effect. However, as renal function is com- spironolactone to titrate the potassium loss due to promised from whatever cause, it becomes an antihyper- untrammeled hydrochlorthiazide. Hydro- reduce stroke and other atherosclerotic disease risk status chlorthiazide has been discussed. African-Americans, along with diabetics, among others, have renal function that is more vulnerable to deteriora- 3. Electrolytes should be checked before because their therapeutic application is the sympatho- starting a hypertensive patient on any drugs, but particu- lytic/antihypertensive effect. The reason for this is that one of the causes ulants do stimulate peripheral alpha2 receptors and raise of secondary hypertension is primary aldosteronism. Alpha2 causes not only hypertension of a salt-retentive type but stimulants are characterized by predisposition to a hyper- also hypokalemia. Once the diuretic is started, the serum tensive discontinuance syndrome that features also tachy- potassium is unreliable for several days. Alpha2 stimulants as mentioned, except for the liver function battery, are all antihypertensive agents work well in conjunction with part of a proper database for initiation of therapy in antihypertensive diuretics. A thiazide diuretic is the least likely of the choices given, to be effective in the case presented. Hypertension is the most powerful risk This patient manifests the characteristics of hypertension factor for stroke, including both hemorrhagic and throm- based on the elevated peripheral resistance as a prepon- botic types. The patient’s vignette suggests that factor for all the atherosclerotic diseases as well but is not a the person is sensitive to or responsive to sympathomi- risk for lung cancer. Elderly people with hypertension, and are logically evaluated for pheochromocytoma. Sen- too, have a tendency for salt-retentive, volume-dependent sitivity and specificity for 24-hour urine metanephrine hypertension. Moreover, hctz and other thiazides, in the levels alone are not sufficient to diagnose pheochromocy- elderly, have a vasodilation effect. Therefore, this patient, being a prediabetic follow-up of essential hypertension is 130/85. This is (elevated C-peptide) with imperfectly treated hyperten- true only for nondiabetic individuals and persons who sion, has a double dose of risk factors and must get imme- are not African-American. The patient should be examined for African-Americans) with hypertension have a primarily an abdominal bruit, specifically a bruit deep in one flank salt- and water-retention mechanism and thus respond to that could be generated by renal artery stenosis. Hypertension significantly hypokalemia and in the absence of diuretic medication or earlier or that which comes on after a person reaches the gastrointestinal or other pathologic loss of potassium is age of 60 must be evaluated for other causes, of which primary aldosteronism until proven otherwise. When a person is at a younger age, the cause is most likely due to a congenital fibrous 13. In primary aldosteronism, the serum band, which has a 2:1 female-to-male occurrence ratio. The level does After a person reaches the age of 60, the cause is more not rise after 4 hours of erect posture. A 24-hour urine likely an atherosclerotic one, which has a 2:1 male-to- study for aldosterone is also measured and indicates female occurrence ratio. None of the other choices has hyperaldosteronism when the excretion is 20 g/24 any specific relevance to the diagnosis of the pathophysi- hours.
Begin at 35 years of age screening more risk for suicide than the population at large buy toradol 10 mg mastercard. Virtually no one in ners consider this to be overly conservative and would that group who has gone so far as to “rehearse” the act favor such screening in the early adult years before setting is without a level of intent or serious consideration out a recommended frequency of testing for each patient for suicide generic 10mg toradol mastercard. A tetanus booster purchase 10 mg toradol otc, usually given as a conditions Td vaccine, should be administered every 10 years. All were cigarette smokers, three of whom had 3 A 45-year-old white woman returns to you for rou- stopped smoking more than 10 years before diagno- tine preventive care, having not seen you except for sis. Her family After telling the patient that lung cancer screening is history is unremarkable except for the mention of far from adequate, he explains that (which of the fol- colon polyps in her sister, who is 10 years older than lowing screening methods) is the most sensitive? He expresses a sugar desire to begin preventive health care under your (E) Chest x-ray, pulmonary function studies, lipid guidance. He has no (B) Glycohemoglobin level check every 3 months other first-degree relatives with colon cancer. The reasons for this are first, that the 60% to 80% evidence of effectiveness as a screening method. This smoking, overweight man first should have organizations with the possible exception of the Ameri- certain screening examinations that begin at the age of can College of Obstetrics and Gynecology. In addition, a lipid screen should be home blood sugars should be recorded upon every visit, obtained (at the least, total cholesterol level, but ideally along with blood sugar levels at the times of visits with the the total spectrum of total, high-density lipoprotein, and physician; and, of course, blood pressure and weight low-density lipoprotein cholesterol levels, as well as serum should be recorded at each visit as well. Comprehensive chemistries including thalmologic examination is done to diagnose early retin- hepatic and renal function studies serve a commonsense opathy of the proliferative type that extends into the purpose in a 50-year-old man who has not had a com- vitreous body, which is treatable by laser. Preventive deteriorates at an accelerated pace in the face of poor Services Task Force, an ultraconservative organization, is blood sugar (and blood pressure) control. Chest x-ray in an asymp- perception, skin nutrition, and pulses, as well as for non- tomatic patient has no screening value, even in a smoker, healing ulcers and other sores. Osteoporosis is the least aggravated testing are also not recommended for routine screening. First, a total cholesterol, and decrease high-density lipoprotein Pap smear is essential in a sexually active woman. In addition, through an increase in weight a mammogram should be performed annually, beginning bearing, obesity promotes osteoblastic in excess of osteo- when the woman reaches the age of 40 years. All screening, starting at 50 years of age in people of average but osteoporosis and osteoarthritis are in turn risk factors risk, should begin annually in a person’s 40s when there is for coronary artery disease. Prostate cancer and glaucoma are two sonable in a patient who has not had a comprehensive conditions that merit screening at the age of 40 in black examination for 6 years. Chest x-ray has no place as a men, whereas in the rest of the male population, otherwise screening tool. The same can be said for coronary heart dis- reason the Guide to Preventive Services, published by the ease and dyslipidemia. African-Americans with hypertension the test in a population with low to average risk allows suffer earlier onset and a greater incidence of cerebrovas- peace of mind in a vast number of cases for any false posi- cular disease (strokes) and renal failure as complications tives that may emerge, leading to emotional and financial than do other group with matched levels of average blood expense. Therefore, the therapeutic target for control of thus subjected to worry and uncomfortable procedures hypertension is set at 125/75 rather than simply settling it such as needle biopsy of the prostate eventually show up for statistically normal blood pressure, 140/ 90. She is active and without com- position of the Guide to Preventive Services of the plaints. She had (B) Patients should carry out total body skin a normal mammogram last year. Her physical examina- (C) Patients over 65 years of age with more than tion is unremarkable. Which of the following preventive 65 should see a physician annually for total measures is clearly indicated for her? In interviewing her, the doctor 4 A 55-year-old female of mixed English and Scottish sometimes wonders if her mind had wandered descent is undergoing her annual pelvic examination, because she cannot discern a coherent message in her Pap smear, and breast examination. Otherwise, she manifests no neurologi- her cigarette smoking comes up, as it does each year. A comprehensive metabolic Again, the doctor takes time to point out the dangers profile reveals both alanine aminotransferase and of smoking, hoping for the “teachable moment. Folstein Mini-Mental State Examination, of which (A) A spouse the sensitivity is known to be 87%. What approxi- (B) A hired caretaker mate percentage of those tested will exhibit a false- (C) A son positive result? He lives alone and wishes to undergo a routine health (E) Falls often occur in mentally competent elderly maintenance examination. She is well legal precedence over the living will of the groomed and socially adept. Patients over 65 years of age with repeated frequently unless there has been a material more than 50 moles should be examined on a regular change in the patient’s living style and weight. Even that conclusion is an inference, not a definite position statement in the 2009 Guide. Pure bulimia is an an inference could be drawn as well from the Guide’s overeating disorder, without, in its pure form, purging or acknowledgment that other high-risk categories include vomiting. The Guide acknowledges the high-risk status like effect so that one of the complications of smoking cessa- of moles’ shapes (asymmetrical), colors (variegated), and tion is weight gain. All the other diseases mentioned in the sizes ( 6 mm) but implies that these characteristics are choices occur at significantly greater incidence in smokers criteria for treatment, not screening. For the slender postmeno- tion is that they cannot, based on “the balance of benefits pausal woman of Celtic origin, osteoporosis is a significant and harms,” recommend for or against total body profes- risk, multiplied 1. Patients most effective in salt/water retention conditions; namely, vary in their propensities to develop alcoholic hepatitis the low renin end of the hypertensive spectrum. An elevated aspartate amin- beta-adrenergic blocking agents are used in the oldest age otransferase level is a nonspecific indicator of hepatocel- group, a greater dosage is required. Thus, being anti-renin lular damage, which is not necessarily present in agents, they are less effective because renin played a less alcoholism. The up-and-go test that for a cancer whose incidence in the population accel- can rule out the possibility that the patient may be physi- erates with age and that the over 60 age group has sur- cally unable to care for himself alone. If the patient can approved by the American Gastroenterology Association perform this satisfactorily in 10 seconds, then he or she with the gold standard being colonoscopy. If the activity requires should be done yearly beginning at the age of 40 years more than 30 seconds, then the patient very likely will until at least the age of 65 as has occurred in this patient. The pneumococcal vaccine is generally indicated once or twice in the adult lifetime. Preparing caregiver(s) and the family benign disease and she does not need Pap smears. Among the serious men- rugs, which present opportunities for elderly individuals tal illnesses to be found in elderly individuals, dementia is to trip.
Fibreoptic bundles are prone to degradation resulting in poor illumination51 and Prisms and mirrors are sometimes added to these laryn- goscope blades to overcome the principal shortcoming diffcult laryngoscopy 10mg toradol fast delivery. So far generic toradol 10 mg free shipping, such modifcations have not proven popular Recently much has been made of the failure of standard or lasting buy toradol 10mg otc. There are numerous other laryngoscope blades beyond the designs already referred to: a few are briefy described here. This therefore enables the laryngoscope blade to be more easily inserted into the Figure 6. Inset shows the blade from the rear to demonstrate the neck extension, large breasts, or those in unusual situa- profle in cross-section. Another device, the Patil–Syracuse handle, allows the handle and blade to and associated soft tissues into the elastic and distensible be locked together at a variety of angles. Poor McCoy blade views of the larynx can be predicted from this model This is based on a standard Macintosh blade modifed by where there is: the insertion of a hinge to give an adjustable tip that is • inadequate craniocervical movement or jaw operated by a lever on the handle (Fig. The blade is opening inserted in the normal way, and if the view is obscured, • relative reduction in the distensible area below the the tip can be fexed so that it further elevates the vallecula foor of mouth (e. Curved blades are designed for the laryngoscope blade is made of multiple sections joined tip to be inserted into the vallecula with the standard together, which in its ‘unfexed’ position resembles a Mac- Macintosh blade being inserted to the right of the tongue, intosh blade. Deployment of a lever after insertion of the while displacing it to the left side, whereas the straight blade fexes the whole length of the blade drawing the tip blade may be inserted posterior to the epiglottis and is upwards in a similar manner to the McCoy blade. There particularly useful for small children and adults with a are limited, but mostly positive, evaluations. Different laryngoscope blades require different tech- Rigid optical laryngoscopes niques for viewing the larynx, which must be learnt and used to maximize utility of that device. For example, the Fibreoptic technology dates back to the 1950s and is Henderson blade (Karl Storz, Germany), a modifcation of described in greater detail below under fexible fbreoptic the Miller blade, is a long straight blade with a ‘C’-shaped laryngoscopes. However, these benefts of the rigid optical laryngoscopes are all only of value if the laryngoscope design reliably facilitates and achieves tracheal intubation. Problems with rigid optical laryngoscopes stem from: • large numbers of devices with limited proof of effcacy • potential diffculty in achieving tracheal intubation despite a good view of the larynx, a common fnding which may be caused by a mismatch between where the device views as opposed to where it steers a Figure 6. In recent years a reduction in to achieve intubation the costs and size of the components, allied with improve- • trauma to unsighted areas in the airway during ments in video technology, has led to a profusion of new passage of tracheal tubes (and stylets) entrants to the market. Image transmission in this class of • increased cost, a very major issue with many devices device may be by fbreoptics, lenses/prisms/mirrors, or costing in excess of £5000 ($7000), often with increasingly, electronically from a distally mounted mini- disposable components also required. Throat specialists with head mounted and hand-held While rigid optical laryngoscopes have much potential, mirrors) at present the majority of devices are of unproven • the ability to retract tissues and make a space to look beneft, in both routine and diffcult cases. Much of the into or beyond (which fexible endoscopes can not do) research that has been performed on these devices is of • the ability to gain a view of the larynx with less 103 poor quality with extrapolation of results from easy mouth opening patients to diffcult patients, use of intermediate endpoints • reduced force and distortion of tissues leading to: and an emphasis on cohort rather than comparative reduced cardiovascular stimulation studies. They are • technical – a larger, brighter, higher-resolution image also principally limited to orotracheal intubation. As with many of these devices there is no This device was for many years the ‘standard’ for this group use of fbreoptics. It is one of the most popular of the but has to a large degree now been superseded. Originally the device was fully reus- broadly curved blade and uses fbreoptics to transmit the able after sterilization, but recently a newer version, the image from the tip to the eyepiece. It is designed to elevate ‘GlideScope Cobalt’, has been introduced with a reusable the jaw without the need for neck extension and for use fexible video baton which inserts into a disposable in patients with limited mouth opening. There are four different sized incorporated in later models to carry the tracheal tube handles in the reusable range (two sizes of a different (Fig. Like many bladed rigid ergonomically engineered, bladed, rigid video laryngo- optical laryngoscopes there is a danger of ‘easy view, dif- scope with an integral pivoting screen and detachable fcult intubation’, particularly if the manufacturer’s instruc- metal CameraStick. After various descriptions of use of clear plastic covers the CameraStick and is curved with a stylets with varying degrees of bend the manufacturers mid-portion angulation (Fig. At present there is have introduced specifc single-use tubes (GlideRite) and only an adult size; a ratchet mechanism at the base of the a dedicated stylet (Fig. A technique that involves device enables a 3 point retraction of the camera part for introduction of the styletted tube from the side of the use in smaller patients. It is operated by standard batteries, patient’s mouth towards the pharynx followed by 90° with a good battery life. Case reports have shown its utility rotation into the feld of view is described; as much of 185 Ward’s Anaesthetic Equipment Figure 6. A single-use plastic blade is copy while the instructor observes or directs progress from mounted on this and incorporates conduits for both the the remote monitor. The device is designed ing in direct laryngoscopy and use of the camera capability to be used in the midline and the tip rotated 90° anteriorly improves visualization of the larynx when compared to on entering the pharynx. It is likely to of image and light-carrying fbreoptics with integral optical have the same limitations, regarding tube choice, as the connections for the detachable light source and camera Airtraq (see below). Note the extreme curvature of the C-Mac ‘D’ blade (on top), for diffcult laryngoscopy, which cannot be used for direct laryngoscopy, see text. The size of the distal viewing lens explains why fbreoptic devices are so be attached and the image viewed on a remote screen con- easily foiled by secretions. Further designs attempt to assist nasal intubations and Airtraq double lumen tracheal tube insertion. First the conduit increases the bulk of user looks into a viewfnder where a series of prisms and the ‘blade’ and may increase the required mouth opening mirrors deliver an illuminated image from the tip of the compared to simpler bladed devices. A camera may different tracheal tube types and sizes will likely alter the 187 Ward’s Anaesthetic Equipment Figure 6. It has been shown for the Airtraq that use of tracheal tubes that are both preformed and whose external diameter is only a little smaller than the internal dimension of the conduit facilitate intu- bation; conversely, relatively small and non-preformed tracheal tubes will fail to adopt the shape of the conduit and therefore exit in a more posterior direction leading to a tendency for failure or oesophageal intubation. Disadvantages include an up to the tracheal tube should be simple and reliably achieved. The epiglottic elevator is modifed in design (a hole in the Optical stylets centre of it enables a view beyond) and colour (it is white, to minimize interference with images). After the device is Optical stylets are preformed rigid or malleable metal inserted a battery powered, low-defnition screen is attached guides containing an optical system (usually fbreoptics) to the connector to display an image. Three sizes cheal tube is loaded onto the stylet, which is then intro- of device are available, covering adults of 30 to 100 kg. While the stylet may be introduced into the trachea this should be avoided, altogether or limited to a small distance to avoid trauma. Oxygen can be insuffated during use, via an attachment for the tracheal tube, in the majority of stylets. It is designed to be introduced from the side of the mouth in a ‘retromolar approach’ using the non-dominant hand to elevate the jaw SensaScope and tongue. There There is limited published experience with the Bonfls is limited, largely positive evaluation of it. In the light of (Clarus Medical, as before) is a similar slightly shorter the arrival of the Ambu aScope (v. Both devices have somewhat greater video stylet will probably precede this publication. Murphy114 who, in • Requires time to learn and skill to use 1967, reported using the newly invented choledochoscope • Cost and necessity for decontamination may limit for intubation of the trachea. The by external diameter of fbrescope (and must be terms fexible intubating fbrescope, endoscope, scope, selected at start of procedure) bronchoscope, laryngoscope, and even tracheoscope are • Passage of tracheal tube over fbrescope is blind, used interchangeably with varying degrees of precision.
8 of 10 - Review by M. Fabio
Votes: 245 votes
Total customer reviews: 245