By F. Goran. Western States Chiropractic College.
Patients with mild to moder- bones mimicking lumbar discopaty with neuropatic pain order cephalexin 500mg on line. With suc- ate carpal tunnel syndrome have normal to mildly abnormal nerve cessful theraphy cheap cephalexin online master card, the patient’s back pain resolved purchase cephalexin 500mg online. Severe disease is suggested by worsening clinical symptoms and clearly abnor- mal electrodiagnostic studies purchase cephalexin 500 mg visa. Alexandria University - Faculty of Medicine, Physical Medicine Six relevant articles were eventually identifed: (Brininger et al and Rehabilitation, Alexandria, Egypt 2007), (M. De Angelis et al 2008), (Shingo Nouta et al 2009), Introduction/Background: Aim of the work. This is arguably valid 60 asymptomatic hands of healthy volunteers as a control group. Conclusion: Good therapeutic were done: (1) Sensory nerve conduction studies: median and ul- response in an 84-year-old patient might not be the case, or might nar nerves; (2) Motor nerve conduction studies: median and ulnar even be a life-impacting outcome in a 30-year-old active patient. She had global muscle hypertonia in both her upper tra- pezius and scalene muscles. Conclusion: Post stroke visual 1 problems may result in compensatory head posture with chronic C. Rehabilitation is focused on correctable visual defcit, 1China Medical University, Department of Physical Therapy Grad- rebalancing neck muscles, optimisation of posture and ergonomics uate Institute of Rehabilitation Science, Taichung, Taiwan with visual biofeedback and pacing of daily activities. Material and Methods: Patients with colorectal 1The First Rahabilitation Hospital of Shanghai, Rahabilitation De- cancer received oxaliplatin administration were routinely referred partment, Shanghai, China, 2Huashan Hospital-Fudan University- from the Department of Oncology and Cancer Center. Both groups are stimulated for 20 times, 5 times a week for 254 a total of four weeks, 60min each time. Material and Methods: A 19-year-old lady Subsequent studies may further demonstrate whether there is a dif- had chronic axial neck pain after right thalamic bleed with intra- ference between these two. Infam- 1Cheras Rehabilitation Hospital, Rehabilitation Medicine, Kuala matory markers and articular symptoms improved after treatment. Lumpur, Malaysia Conclusion: In conclusion, post-chemotherapy rheumatism may be seen after completion of chemotherapy in patients with Hodgkin Introduction/Background: Rheumatoid arthritis is a chronic pro- lymphoma. Clinicians should kept in mind this diagnosis to speed gressive disease causing infammation in the joints and resulting in up the diagnosis process without unnecessary investigation and it painful deformity and immobility, especially in the fngers, wrists, will be better if the patients are informed about this complication feet, and ankles. She was diagnosed with Seropositive Rheumatoid Arthritis in Jul 2013 after a four years period of persistent and recurrent joint pain and swell- 258 ing involving both her ankles, knees and elbow joints. She was 1 Gulhane Military Medical Academy - Haydarpasa Research and also noted to have multiple bilateral joint contractures involving her Training Hospital, Physical Medicine and Rehabilitation, Istanbul, shoulders, wrists and knees. She Material and Methods: A-40-yr man who was diagnosed ankylos- could hardly stand because of the bilateral knee pain. Cryotherapy ing spondylitis presented to our outpatient clinic due to the increase was also provided however this only improved her pain slightly. Her standing balance improved and Sulfasalazine (2,000 mg daily) and dicıofenac (200 mg daily) treat- by the 5th cycle of hydrotherapy, she was able to walk 5 rounds in ments were discontiniued because of their side effects. She progressed very well in the ab treatment (40 mg) was started every other week. Two days after hydrotherapy pool, walking independently under supervision of our the frst adalimumab application, patient presented to our outpatient therapist. There is no fever and there is no to her late presentation to hospital and hence to rehabilitation, this increased expectoration. There were also complaint of cough after young lady’s dream of walking again is still beyond expectations. Results: The reason of cough was considered Adalimumab and treatment was terminated. The patient had no complaint of cough in the control examination 257 2 weeks later. Tekin Introduction/Background: There are various musculoskeletal 1Gulhane Military Medical Academy - Haydarpasa Research and manifestations that may develop in a patient after chemotherapy. Training Hospital, Physical Medicine and Rehabilitation, Istanbul, These manifestations may be due to metastasis to musculoskeletal Turkey structures, paraneoplastic syndrome or immune reactions as well as adverse reactions to cancer specifc chemotherapy. It has been described in patients with some kinds of cancers antagonists is a well-established phenomenon. Ma- monoclonal antibody, and who unexpectedly developed psoriatic terial and Methods: A 39-year-old man presented with a 6 weeks skin lesions. Material and Methods: Case: A 37-year-old man who history of symmetric arthralgia on his bilateral hand and foot joints. Sulfasalazine (2,000 mg daily) and in- sis and treated chemotherapy, including palonosetron, doxorubicin, domethacin (75 mg daily) treatment was discontinued about a year cyclophosphamide, etoposide, vincristine. His last chemothrapy ago because of insuffcient antirheumatic effect and adalimumab was 6 weeks before. Physical examination revealed no swelling (40 mg subcutaneously) treatment was started every other week. According to her history, she had not received pruritic skin lesions of up to 10 cm in diameter as well as some pus- a regular treatment for 35 years but she have used lefunomide (20 tules on palms, arms and especially on both plantar area appeared. On Psoriasis pustulosa was clinically and histologically confrmed by examination there was no fever and swelling of hand, wrist or any a dermatologist. Ciclosporin A and topical treatment for was widespread bilateral rough rales by auscultation. Laboratory tests re- treatment is planned after becoming sure that the skin lesions are not vealed: White blood cell 11. Results: We performed three courses of steroid the severity of the symptoms in some patients, but which biological pulse therapy (methylpredonisolone 500 mg x 3 day/course) and agent would prove to be less harmful could not be predicted. Lefuno- mide was discontinued and methotrexate (10 mg/week) hydroxy- chloroquine (400 mg twice a day) and prednisone (4 mg/day) was 260 started. Kiralp1 1 Rheumatoid arthritis is known as a chronic systemic infamatuar dis- 1Gulhane Military Medical Academy - Haydarpasa Research and ease which effects periferic small joints. We presented a case who Training Hospital, Physical Medicine and Rehabilitation, Istanbul, has the diagnoses of these two diseases both. Her low back and hip pain had manifestations include bronchiolitis obliterans and crycoarytenoid increased in addition to the pain in the hand joints in the last 1 month. We present a case of a patient with pulmonary involve- On physical examination, bilateral wrists, 1. Lum- al and Methods: Case: A 70-year-old man with a 36-year history of bar range of motion was limited minimally in all directiond. Lumbar rheumatoid arthritis had been on methotrexate, sulfosalazine, and Schober test was measured as 4,5 cm and chest expansion was meas- prednisone admitted to our outpatient clinic. There was decreased left lung sounds by ausculta- matoid arthritis was diagnosed with ankylosing spondylitis in the tion. Laboratory tests revealed: erythrocyte sedimentation rate of light of these fndings and treatment has been revised. Chest X-ray showed decreased left tis is a rare situation, it should be considered in the diagnosis. Conclusion: There is 1 1 1 evidence of an association between pulmonary complications and E. Adalimumab is a humanized monoclonal antibody, it would Training Hospital, Physical Medicine and Rehabilitation, Istanbul, have the potential advantage of being less immunogenic. However, Turkey some authors have suggested that its use might induce pulmonary complications. Herein, we want to draw attention to successful Introduction/Background: Pulmonary involvement is one of the treatment of pulmonary involvement of rheumatoid arthiritis with extra-articular manifestations of rheumatoid arthritis and includes adalimumab but it should be kept in mand that it may also cause pleural effusion, parenchymal nodules, interstitial involvement, pulmonary complications. We present a case of a patient with pulmonary involvement of rheumatoid arthiritis and treated with pulse steroid therapy. All questions are about sleep and they were well understood by ment of Otorhinolaryngology, Ankara, Turkey, 3Ministry of Health patients which showed the face validity. Introduction/Background: The aim of this study was to investigate Pearson’s (r) Signifcance (p) the inner ear function in patients with psoriatic arthritis. Statistical comparisons between both groups were per- formed using chi-square test and Mann- WhitneyU test. Latif3 the evaluation of hearing frequencies of the patients between 4,000 1Ahvaz Jundishapur Univeristy of Medical Sciences - Ahvaz - Iran, and 6,000 Hz, a statistically signifcant difference was found relative 2 Physical Medicine and Rehabilitation, Ahvaz, Iran, Ahvaz Jundis- to the control group (p<005). When compared with 3 the control group, a statistically signifcantly difference was found Ahvaz, Iran, Ahvaz Jundishapur Univeristy of Medical Sciences at 3,000 and 4,000 Hz. Conclusion: Our study provides - Ahvaz - Iran, Health Research Center-Diabetes Research Center, strong evidence suggesting the necessity of monitorization of these Ahvaz, Iran patients regarding sensorineural hearing loss so as to take measures Introduction/Background: Median nerve involvement in wrist is against the development of hearing loss during early stage which one of the most common compression neuropathy which drives the may be another disability in patients with PsA which is itself a po- patients to musculocutaneus clinics such as orthopedy, neurology tential cause of severe disability. For estimating the amount of nerve injury, all the amounts of patients’ pain severity, 264 clinical and electrodiagnostic severity data were used by different researchers.
Tests of chi-square are used to determine whether there is an association between two categorical variables order cephalexin with paypal. In health research buy generic cephalexin 500mg line, a test of chi-square is frequently used to assess whether disease (present/absent) is associated with exposure (yes/no) generic cephalexin 750 mg visa. For example cephalexin 250mg free shipping, a chi-square test could be used to examine whether the absence or presence of an illness is independent of whether a child was or was not immunized. Chi-square tests are appropriate for most study designs but the results are inﬂuenced by the sample size. The data for chi-square tests are summarized using crosstabulations as shown in Table 8. Tables can have larger dimensions when either the exposure or the disease has more than two levels. In a contingency table, one variable (usually the exposure) forms the rows and the other variable (usually the disease) forms the columns. For example, the exposure immunization (no, yes) would form the rows and the illness (present, absent) would form the columns. The four internal cells of the table show the counts for each of the disease/exposure groups; for example, cell ‘a’ shows the number who satisfy exposure present (immunized) and disease present (illness positive). As in all analyses, it is important to identify which variable is the outcome variable and which variable is the explanatory variable. This can be achieved by either: • entering the explanatory variable in the rows, the outcome in the columns and using row percentages, or • entering the explanatory variable in the columns, the outcome in the rows and using column percentages. A table set up in either of these ways will display the per cent of participants with the outcome of interest in each of the explanatory variable groups. In most study designs, the outcome is an illness or disease and the explanatory variable is an exposure or an experimental group. However, in case–control studies in which cases are selected on the basis of their disease status, the disease may be treated as the explanatory variable and the exposure as the outcome variable. Thus, if repeat data have been collected, for example, if data have been collected from hospital inpatients and some patients have been readmitted, a decision must be made about which data, for example, from the ﬁrst admission or the last admission, are used in the analyses. The expected frequency in each cell is an important concept in determining P val- ues and deciding the validity of a chi-square test. For each cell, a certain number of participants would be expected given the frequencies of each of the characteristics in the sample. When the expected frequency of cell is less than 5, the signiﬁcance tests of the Pear- son’s chi-square distribution becomes inaccurate due to the small sample size. Thus, the Pearson’s or continuity-corrected chi-square values should be used only when 80% of the expected cell frequencies exceed 5 and all expected cell frequencies exceed 1. When a chi-square test is requested, most statistics programs provide a number of chi-square values on the output. The chi-square statistic that is conventionally used depends on both the sample size and the expected cell counts as shown in Table 8. Fisher’s exact test is generally calculated for 2 × 2 tables and, depending on the program used, may also be produced for crosstabulations larger than 2 × 2. In a 2 × 2 contingency table, the Pearson’s chi-square produces smaller P values than Fisher’s exact and a type I error may occur. The linear-by-linear test is a trend test and is most appropriate in situations in which an ordered exposure variable has three or more categories and the outcome variable is binary. If the sample size is small or some cells have a low count, the ‘exact’ P values should be reported since the asymptotic P values will be unreliable. The exact calculation based on the exact distribution of the test statistics provides a reliable P value irrespective of the sample size or distribution of the data. The observed count is the actual count in the sample and is shown in each cell of the crosstabulation. The expected count is the expected value due by chance alone and is calculated for each cell as the: Row total × Column total Grand total For cell a in Table 8. The Pearson chi-square value is calculated by the following summation 256 Chapter 8 from all cells: ∑ 2 (Observed count − Expected count) Chi-squared value = Expected count The continuity corrected (Yates) chi-square is calculated in a similar way but with a cor- rection made for a smaller sample size. The null hypothesis for a chi-square test is that there is no signiﬁcant difference between the observed frequencies and expected fre- quencies. Obviously, if the observed and expected values are similar, then the chi-square value will be close to zero and therefore will not be signiﬁcant. The larger the observed and expected values are from one another, the larger the chi-square value becomes and the more likely the P value will be signiﬁcant. This sample was not selected randomly and therefore only percentages will apply and the terms incidence and prevalence cannot be used. However, chi-square tests are valid to assess whether there are any between-group differences in the proportion of babies with certain characteristics. Question: Are males who are admitted for surgery more likely than females to have been born prematurely? Null hypothesis: That the proportion of males in the premature group is equal to the proportion of females in the premature group. Variables: Outcome variable = prematurity (categorical, two levels) Explanatory variable = gender (categorical, two levels) The command sequence to obtain a crosstabulation and chi-square test is shown in Box 8. Crosstabs Gender Recoded * Prematurity Crosstabulation Prematurity Premature Term Total Gender recoded Male Count 33 49 82 % within gender recoded 40. In this example, the sample size is too small for the chi-square distribution to approxi- mate the exact distribution of the Pearson statistic and so the Pearson chi-square value should not be reported. The Fisher’s exact test would be reported in this study because the sample size is only 141 children. This result can be reported as ‘Fisher’s exact test indicated that there was a signiﬁcant difference in prematurity between males and females (40. The larger the difference between the rates in two groups, the smaller the sample size required to show a statistically signiﬁcant difference. It is useful to include the 95% conﬁdence intervals when results are shown as ﬁgures because the degree of overlap between them provides an approximate signiﬁcance of the differences between groups. The interpretation of the degree of overlap is discussed in Chapter 3 (also see Table 3. Many statistics programs do not provide conﬁdence intervals around frequency statis- tics. However, 95% conﬁdence intervals can be easily computed using an Excel spread- √ sheet. The standard error around a proportion is calculated as [p(1–p)∕n] where p is Rates and proportions 259 the proportion expressed as a decimal number and n is the number of cases in the group from which the proportion is calculated. An Excel spreadsheet in which the percentage is entered as its decimal equivalent in the ﬁrst column and the number in the group is entered in the second column can be used to calculate conﬁdence intervals as shown in Table 8. The formula for the standard error is entered into the formula bar of Excel as sqrt (p × (1 − p)/n) and the formula for the width of the conﬁdence interval is entered as 1. This width, which is the dimension of the 95% conﬁdence interval that is entered into SigmaPlot to draw bar charts with error bars, can then be both subtracted and added to the proportion to calculate the 95% conﬁdence interval values shown in the last two columns of Table 8. The calculations are undertaken in proportions (decimal numbers) but are easily con- verted back to percentages by multiplying by 100, that is, by moving the decimal point two places to the right. Using the converted values, the result could be reported as ‘the percentage of male babies born prematurely was 40. This was signiﬁcantly different than the percentage of female babies born prematurely which was 20. Because the value of ‘n’ is integral in the denominator of the calculation of conﬁdence intervals, the larger the sample size, the smaller the conﬁdence will be, indicating greater precision in the result. In general, a large sample size is required to reduce 95% conﬁdence intervals below a width of 5%. The lack of overlap between the conﬁdence intervals is an approximate indication of a statistically signiﬁcant difference between the two groups (see Table 3. Research question Question: Are the babies born in regional centres (away from the hospital or overseas) more likely to be premature than babies born in local areas? Null hypothesis: That the proportion of premature babies in the group born locally is not different to the proportion of premature babies in the groups born regionally or overseas. Variables: Place of birth (categorical, three levels and) prematurity (categorical, two levels) In this research question, there is no clear outcome or explanatory variable because both variables in the analysis are characteristics of the babies. This type of question is asked when it is important to know about the inter-relationships between variables in the data set. If prematurity has an important association with place of birth, this may need to be taken into account in multivariate analyses.
The weaknesses of the study included nonrandomization buy 250 mg cephalexin fast delivery, the use of historic controls discount cephalexin 500mg on-line, 110 Mayhall and the simultaneous administration of other oral antimicrobial agents buy cephalexin cheap. The authors also noted that by eradicating rectal carriage with vancomycin and preventing infection purchase cheapest cephalexin, they administered only 25% as much vancomycin to the group given oral vancomycin prophylaxis as was needed to treat the infections in the control group. Patients with colonization or infection were treated for five days with enteral vancomycin. In a report of a second outbreak, colonized neonates were treated with mupirocin twice daily to the anterior nares and the umbilical area for seven days (115). Because all of these control measures were implemented at the same time, it was not possible to determine what effect the triple dye had in controlling the outbreak. Other sites of colonization or infection are less common but may have to be sought if epidemiologically indicated. Two other species, Enterococcus gallinarium and Enterococcus casseliflavus, are motile and display intrinsic vancomycin resistance (118). Vancomycin resistance in enterococci is mediated by the production of D-Alanine:D- Alanine ligases of altered substrate specificity (119). Vancomycin does not bind to D-Lac, thus permitting cell wall synthesis to continue. This transposon is most often carried on a plasmid and can be transferred to other gram-positive cocci. Other types of ligases with altered substrate specificities are vanC [D-Ala- D-Ser (serine)], vanD (D-Ala- D-Lac), and vanE (D-Ala- D-Ser). These latter species have intrinsic low-level resistance to vancomycin (8 to 16 mg/mL). Isolates carrying the esp gene seem to be associated with in-hospital spread and possibly with increased virulence. A univariate analysis of patients with and without a urinary tract infection revealed a significant relationship between having a malignancy and a urinary tract infection (131). Similar to adult patients, only about 1 in 10 colonized patients develop infection. Drugs listed included cephalosporins, metronidazole, vancomycin, carbapenems, ticarcillin–clavulanate, and quinolones. Risk factors from Tables 4 and 5 that appear multiple times are use of antacids and enteral feedings. Thus, the focus for control and prevention is on the following: (i) detection of colonized patients by surveillance cultures; (ii) barrier isolation; (iii) hand hygiene; (iv) environmental decontamination; and (v) control of antimicrobial (particularly vancomycin) use. Colonized patients have been detected by screening stool specimens submitted to the clinical microbiology laboratory for Clostridium difficile toxin assay (165). This may have been due to the extensive use of antimicrobial agents in the burn unit where the study was performed. Surveillance cultures can be made more efficient by using a selective culture media to suppress growth of other microorganisms that will likely contaminate the specimens (144,164). This recommendation is further supported by a study that found that rectal and perirectal swabs had approximately the same sensitivity (79%) (167). The guideline also recommends donning clean nonsterile gloves prior to entering the room. The authors state that an easily cleanable nonporous material is the preferred upholstery in hospitals. The effectiveness of decontamination of the environment depends on the method used. In one study, the investigators observed that cleaning environmental surfaces with a cleaning rag sprayed with a quaternary ammonium disinfectant was significantly less effective than dipping the cleaning rag into a bucket of the same disinfectant, drenching all surfaces, allowing the surfaces to remain wet for 10 minutes, and then wiping the surfaces dry with a clean towel (177). Using the method in which the disinfectant was sprayed on the cleaning rag took 2. Based on this study, the bucket method is the preferred method for decontaminating environmental surfaces. In another study investigators examined the elements of environmental cleaning to determine whether changes in cleaning products, cleaning procedures, or performance of cleaning personnel would lead to more effective cleaning of the environment (178). The authors noted that the performance of cleaning personnel was the most important factor in the effective decontamination of the environment. The effectiveness of cleaning personnel performance was related to the number of environmental sites cleaned. After patient contact, hands should be washed with an antiseptic-containing soap or an alcohol hand rub should be applied. Six studies on the use of piperacillin–tazobactam in place of third-generation cephalosporins and ticarcillin–clavulanate have been published (181–186). However, there were several significant differences between the two groups and the authors did not apply multivariable analysis to obtain a clearly un- confounded conclusion of their results. Only one of the latter studies was adequately designed to provide definitive results (185). A novel methicillin-resistance cassette in community-acquired methicillin-resistant Staphylococcus aureus isolates of diverse genetic backgrounds. Intrafamilial spread of highly virulent¨ Staphylococcus aureus strains carrying the gene for Panton-Valentine leukocidin. Community-acquired methicillin-resistant Staphylococcus aureus isolated in Switzerland contains the Panton-Valentine leukocidin or exfoliative toxin genes. Emergence and spread of community-associated methicillin- resistant Staphylococcus aureus in rural Wisconsin, 1989 to 1999. Widespread skin and soft-tissue infections due to two methicillin-resistant Staphylococcus aureus strains harboring the genes for Panton-Valentine Leukocidin. Genetic diversity among community methicillin-resistant Staphylococcus aureus strains causing outpatient infections in Australia. Emergence of methicillin-resistant Staphylococcus aureus with Panton-Valentine leukocidin genes in central Europe. Risk factors and molecular analysis of community methicillin- resistant Staphylococcus aureus carriage. Community-acquired methicillin-resistant Staphylococcus aureus colonization in healthy children attending an outpatient pediatric clinic. Epidemiology and clonality of community-acquired methicillin-resistant Staphylococcus aureus in Minnesota 1996-1998. Global distribution of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus, 2006. Epidemic community-associated methicillin-resistant Staphylococcus aureus: recent clonal expansion and diversification. Emergence of and risk factors for methicillin-resistant Staphylococcus aureus of community origin in intensive care nurseries. Modeling the invasion of community-acquired methicillin- resistant Staphylococcus aureus into hospitals. Plasmid-mediated resistance to vancomycin and teicoplanin in Enterococcus faecium. Vancomycin-resistant Enterococcus faecium on a pediatric oncology ward: duration of stool shedding and incidence of clinical infection. Toxin-antitoxin systems are ubiquitous and plasmid-encoded in vancomycin-resistant enterococci. Clonal analysis of methicillin-resistant Staphylococcus aureus strains from intercontinental sources: association of the mec gene with divergent phylogenetic lineages implies dissemination by horizontal transfer and recombination. Severe Staphylococcus aureus infections caused by clonally related community-acquired methicillin-susceptible and methicillin-resistant isolates. Staphylococcal resistance revisited: community-acquired methicillin resistant Staphylococcus aureus—an emerging problem for the management of skin and soft tissue infections. Community-acquired methicillin-resistant Staphylococcus aureus: epidemi- ology and potential virulence factors. Control of endemic methicillin-resistant Staphylococcus aureus: a cost-benefit analysis in an intensive care unit. Staphylococcus aureus rectal carriage and its association with infections in patients in a surgical intensive care unit and a liver transplant unit. Acquisition of methicillin-resistant Staphylococcus aureus in a large intensive care unit. Identification of a variant “Rome clone” of methicillin- resistant Staphylococcus aureus with decreased susceptibility to vancomycin, responsible for an outbreak in an intensive care unit. Eradication of endemic methicillin-resistant Staphylo- coccus aureus infections from a neonatal intensive care unit.
Adjunctive corticosteroid therapy for tuberculosis: a critical reappraisal of the literature cheap 750 mg cephalexin with mastercard. Chemotherapy and its combination with corticosteroids in acute miliary tuberculosis in adolescents and adults: analysis of 55 cases buy cephalexin no prescription. The use of adjunctive corticosteroids in the treatment of pericardial cheap 250 mg cephalexin mastercard, pleural and meningeal tuberculosis: do they improve outcome? Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care settings purchase cephalexin 500mg with mastercard. Francis Medical Center, Trenton, and Seton Hall University School of Graduate Medical Education, South Orange, New Jersey, U. Ricketti Section of Allergy and Immunology, Department of Medicine, and Internal Medicine Residency, St. Francis Medical Center, Trenton, and Seton Hall University School of Graduate Medical Education, South Orange, New Jersey, U. Vernaleo Division of Infectious Diseases, Wyckoff Heights Medical Center, Brooklyn, New York, U. Half a league, half a league, Half a league onward, All in the valley of Death Rode the six hundred. Victims of bioterrorism are often not immediately recognized, and present special and daunting challenges. However, before these challenges can be addressed, basic precepts must be followed. Assist in the epidemiologic investigation and manage the psychological consequences. These 10 steps intended for battlefield conditions are applicable to our own battlefield—the intensive care unit. To this, we add that the clinician-in-charge must put himself into the mind of the enemy. By the application of each of these steps, the intensivist can lead his clinical team to safely, efficiently, and competently diagnose and deliver the essential care to the victims of a bioterrorism, and at the same time participate in the overall ongoing defensive response to these attacks upon ourselves and society. This definition has been expanded to include attacks against animals and plants (2). Between 1900 and 1999, there were 415 incidents (278 cases between 1960 and 1999) of the use or attempted use of chemical, biological, or radiological materials by criminals or terrorists. In recent years, investigations into these threats, especially biological threats, have dramat- ically increased (10). Awareness of the history of the use of biological weapons will help the clinician better appreciate future epidemiologic threats. Maintain an Index of Suspicion Specific epidemiologic characteristics should raise the clinician’s index of suspicion that he is dealing with a bioterrorism event. Protect Yourself (and Your Patients) Intensive care units render care to a relatively small proportion of hospitalized patients, but nationally account for <20% of health care–associated infections (13). A review of infection control is essential in order to effectively apply isolation principles in the event of a bioterrorist attack. Standard precautions include hand hygiene, safe injection practices and handling of sharps, personal barrier precautions and supplies, and addressing the risk of contamination of the patient environment. Newer elements such as respiratory hygiene/cough etiquette, safe injection practices, and the use of masks for inserting catheters or procedures involving a lumbar puncture have been added (13). These precautions are always applied together with standard precautions, and may be used in combination with one another. Single rooms are always preferred, but where cohorting is the only option, there must be greater than 3 ft distance between beds (13). Droplet precautions do not require rooms with special air handling or ventilation. In addition to other protective garments, all those entering the room must wear a mask. Airborne precautions are required for infectious agents that are a threat over long distances (i. It is mandatory to implement a respiratory protection program that includes the use of respirators, fit testing, and user seal checks. Where this cannot be accomplished, an N95 or higher-level respirator must be worn (13). As identification of the pathogen may take one or more days, decisions must be made based upon clinical presentation (syndromic application—see Table 4) (13,16). Table 5 lists the recommended isolation precautions for each of the organisms by class (13,16–22). Table 1 Classification of Bioterrorism Agents Category and agents Characteristics Category A “High-priority agents include organisms that pose a risk to national security because they: Anthrax (B. Other viruses within the same group are louping ill virus, Langat virus, and Powassan virus. Tick-borne hemorrhagic fever viruses [Crimean-Congo ease of production and dissemination; and hemorrhagic fever (Nairovirus-a Bunyaviridae), Omsk hemorrhagic fever, Kyasanur forest disease and Alkhurma viruses]. Table 3 Epidemiologic Characteristics of a Bioterrorist Attack Epidemiologic characteristic Comments and special considerations in a civilian attack Epidemic of similar disease in a limited The combination of prolonged incubation periods and the population release of an airborne pathogen at a transportation hub (subway, train, or bus station, or airport) may allow infected individuals to travel considerable distances before becoming ill. Incubation periods Casualties occurring within hours of one another suggest chemical or toxin. Characteristics in epidemic curve A sudden rise and fall in the number of cases or a steady increase in the number of casualties suggests a biologic agent. Unexplained increases in morbidity and mortality This may not become apparent early after an attack, especially in an individual institution. Variations in the cross section of those exposed to the pathogen: the most severely affected will be the elderly and those with common chronic diseases (cardiac and pulmonary diseases)—those most commonly admitted to intensive care units. More severe disease than expected from the This is often the case with compromised patients who are isolated pathogen and failure to respond to admitted to the intensive care unit. Vector-transmitted disease occurring in an area devoid of the vector Multiple simultaneous cases of different In a single institution, this may only become apparent infectious diseases in the same population sometime after the initial cases of each disease present themselves. A single case of an uncommon disease Examples: All category A pathogens, smallpox (V. Disease unusual for an age group Unusual strains, variants or antimicrobial We have become so accustomed to seeing multidrug resistance patterns resistance, that this may not arouse suspicion. Similar or genetically identical organisms This will not be initially apparent and will require a high isolated from different sources at different enough index of suspicion for the clinician to order the times, especially those that do not appear to appropriate genetic testing. Disease outbreak that is both human and Unless there is a history of the patients’ pets or livestock zoonotic; an increase is noted in dying or dead becoming ill, this will not be apparent to the clinician, animals especially in an inner city hospital. Assess the Patient Many if not most of the likely agents to be used for bioterrorism have overlapping incubation periods and clinical presentations. Where under normal circumstances we could depend on epidemiology to assist us in narrowing our differential diagnosis, for the initial cases, we must rely exclusively on a syndromic approach prior to laboratory confirmation. Table 6 (1,5,23–30) provides a comparison of clinical presentations for Class A agents. Bioterrorism Infections in Critical Care 439 Table 4 Abbreviated Syndromic-Based Isolation Precautions Clinical presentation Transmission-based precautions in or syndrome addition to standard precautions Comments Diarrhea Contact precautions Meningitis Droplet precautions No pulmonary infiltrates. Type X facility is the same as a contacts under surveillance type C facility except it need who become febrile (! The Chest Radiograph The chest X ray is one of the most important tools of the intensivist. Chest radiographic findings for selected pathogens are described in Table 8 (33,43–55). To date, inhalational anthrax represents the most significant bioterrorist threat to challenge the intensivist. Table 5 Recommended Transmission-Based Isolation Precautions Recommended Pathogen isolation precautions Comments Class A pathogens Anthrax (B. Environmental: Standard, contact, Until decontamination, wear respirator (N95 or aerosolzable spore- droplet, airborne. Nonvaccinated health care workers should not provide care when vaccinated health care workers are available. All impermeable gowns, face/eye protection with caregivers in masks, goggles, or face shields, and waste contact with the handling.
Commercially produced table sugar (sucrose) comes either from sugar cane or from sugar beet order cephalexin 250mg on line. The enzymati- cally enhanced corn syrup purchase cephalexin 750mg online, now fructose order online cephalexin, is mixed with pure corn syrup order 500mg cephalexin amex, which is 100 percent glucose, in varying percentages, and is found virtually in all processed foods and beverages, including soft drinks, cookies, crackers, salad dressings, snack foods, soups, etc. Even if these sugars were metabolized perfectly by our bodies with no adverse effects, they are totally unnecessary and are only added 6 calories. The fructose in a piece of fruit is held in the complex of water, fiber, and phytochemicals, so with fruit your body is getting less of a sugar load as well as a slower release of the sugar and more pro- tective compounds with it. We shouldn’t be eating a lot of foods that have either one of these totally unnecessary added calorie sweeteners in the first place. Since natural sugars are a calorie source when consumed in excess, they can increase weight and inflammation like other calories. But it is harder to eat excess calories when eating whole, unprocessed foods with no added sugars of any type. In general, natural sugars are better than “added” manufac- tured sugars because they come in a complex of fiber and other phytonutrients that slow the release of these sugars into our bod- ies, making the metabolism of the sugar less stressful to our en- docrine (adrenal glands, liver, pancreas, brain) organs over time. Nutrients that come with these natural sugars in complex whole foods assist in the metabolism of that sugar instead of taking those nutrients from body stores needed for this and other important bodily processes. The truth is sucrose, or table sugar (fructose and glucose), and high fructose corn syrup (fructose and glucose) are metabolized similarly and, in small amounts don’t cause disease any more than natural sugars found in whole foods. And these two unnecessary calorie sweet- eners are added to most refined foods and drinks which we consume large quantities of in this country. You also cut out the stress to the or- gans that have to process these added sugars (adrenals, liver, and pancreas). Excess sugar equals excess calories and inflammation, which are both very harmful to our health. Just eat whole foods (vegetables, fruit, beans, raw nuts and seeds, and whole grains) and you don’t have to read a label or worry about added sugars. Sugar’s Job: Get into the Cell and be “Burned” Sugar’s role is to be burned as energy in the cell. If insulin, the doorman of the cell, can’t unlock or open the door for any reason, known or unknown, sugar can’t get into the cell, and bad things start to happen. On the outside of the cell, if sugar in the bloodstream starts to elevate, an excess of blood sugar can cause a variety of long-term ill effects to the body, slowly damaging blood vessels, nerves, eyes, and kidneys, and actually increase the aging process. With the rise in blood sugar, insulin keeps being secreted by the pancreas to try to open the door of the cell to get sugar into the cell to be burned as energy. If the sugar is a simple sugar, it generally gets absorbed rap- idly, causing the pancreas to respond quickly, which it does very well. If, over time, this process challenges those cells in the pancreas enough, they start to wear out and fail to produce insulin adequately. The person might even- tually develop insulin-dependent diabetes (meaning they have to - 109 - staying healthy in the fast lane take insulin shots to lower their blood sugar). Excess calories, weight, and excess fat in the cell (intramyocellular fat) can all increase the risk of insulin resistance, leading to higher circulating insulin (and blood sugar) levels. So while it is important to eat low glycemic carbohydrates, it’s also important to keep your total calorie and fat levels down to improve insulin resistance. Since almost all chronic diseases (heart disease, cancer, diabetes, bone loss, stroke, hyper- tension, and degenerative eye and brain disorders) come from ex- cessive inflammation, excessive insulin is not a good thing. Insulin is also a growth-promoting hormone, so aside from increasing in- flammation it can also increase the risk of cancer. Bottom line: if you control your blood sugar (fasting < 90 mg/ dl, some say < 80 mg/dl is optimal) and keep you insulin low (<10 uU/ml, some say lower), you reduce your risk of chronic inflam- matory diseases and slow the aging process. Staying Healthy “Pearl” about Sugar One common point that is a true belief of every dietary philoso- phy I know, from raw food veganism to the high-fat, high-protein diet proponents, and everything in between: The goal of all diets is to control blood sugar (and insulin) levels for optimal health and chronic disease prevention and/or reversal. Controlling blood sugar and insu- lin levels—sometimes called “good glycemic control”—increases - 110 - the big three: alcohol, caffeine, and sugar optimal function and slows the aging process. That is why almost any diet philosophy can work if you use the diet to achieve this goal. Ideally, you want to control blood sugar and insulin levels at a calorie level that allows you to stay lean but provides you with the maximum amount of vitamins, minerals, and phytonutrients to protect you and optimize your metabolism. I hate to be repetitive, folks, but that’s a micronutrient-rich, plant-strong, unprocessed vegan diet. Sugar and Your Intestines Undigested simple sugars can go into the bowel, and bacte- ria—generally in the large intestine—can work on these sugars and produce gas and bloating or more complex chemicals called organic acids that can have extra intestinal effects (other places in the body). Similar symptoms may occur with undigested simple sugars increasing fungal growth. Cutting out all refined sugars and sometimes even whole un- processed sugars from foods and drink can dramatically reduce gut symptoms and sometimes systemic problems (headaches, joint pain, etc. Adding a good probiotic (good bacteria) along with antifungal treatment may also provide additional benefit. Some people need stool exams to see if there is any bacterial (or fungal) overgrowth to be treated. Sometimes I give a short course of antibiotics for antibiotic sensitive bacteria I find in a stool exam, which is overgrown in the gut. This leaves no sugars for the intestinal bacteria to feed on and produce unwanted gas and metabolites. This diet has also been used with success in some autistic children as part of an overall treatment strategy. These forms of complex sugars put less stress on your adrenal glands, pancreas, and liver, producing a smoother blood sugar rise and fall. Usually, but not always, low glycemic foods are found in whole, unrefined plant foods, especially beans, lentils, peas, and some pastas. Sugar and Your Brain Your brain doesn’t like to be without two things for too long: oxygen and sugar. A lack of either can cause mental fogginess, dif- ficulty thinking, irritability, or even headaches in some. Neurons manufacture enzymes and neurotrans- mitters that are transported to the ends of their nerve branches, which takes energy. Nerve transmission is a very energy-intensive use of glucose, consuming one-half of all the brain’s energy (nearly 10 percent of the whole body’s energy). Reduced amounts of glucose can impair acetylcholine synthesis, which is an important neurotransmitter in the brain for memory. As previously mentioned, when you eat something that causes a rapid rise in - 112 - the big three: alcohol, caffeine, and sugar your blood sugar, your pancreas secretes a burst of insulin. Low blood glucose levels can lead to a significant deterioration in attention abilities. The goal again is to eat slow-release sugars (low glycemic foods) to give your brain a constant flow of energy. The carbohydrates you eat should be in their whole, unrefined state: whole fruit, beans (and bean spreads), lentil, peas, pastas, whole/sprouted grains, root vegetables such as yams, sweet potatoes, and nuts and seeds. Under stress or if you just want to eat for any reason, just have whole foods available in your immediate surroundings and eat them. Make sure you are eating whole, unpro- cessed, carbohydrate-rich, protein adequate, nutrient-dense foods with lots of phytochemicals and fiber when you eat them. While I talk about improving the health of the United States and the world by changing macronutrition or by eating different food groups, these facts don’t take into account the role of food intolerance on quality of individual life. Making broad, sweeping dietary and lifestyle changes, as I have mentioned throughout the book, if implemented, will have great benefits to society. Some individuals, while reducing their risk of the major chronic diseases, may not feel well, or will have certain symptoms or conditions aggravated on a whole-food diet because of food sensitivities. The most glaring example is usually wheat consumption and food intolerance, assuming you already got rid of all milk products! Some people believe that wheat, whole grain or not, is a greater problem than dairy products from a food intolerance point of view. Ideally, I would love all my patients to go off all dairy, wheat (and glutinous grains), added sugars, caf- feine drinks, and alcohol for a month or two and eat a diet of whole, mainly plant-based foods. You would see a great deal of improve- ment in a lot of people and relief from a lot of different complaints. Wheat sensitivity could also be caused by celiac disease, which is a severe form of intolerance to the gluten in the wheat that, if gone unnoticed, can result in severe malnutrition and bowel, joint, and neurological symptoms (celiac. Its whole- ness really doesn’t matter, though I must admit I think sometimes the whole grain is more reactive than white flour foods, which are less nutritious.
Etching for just 20 s with a range of concentrations of acid but most often buy genuine cephalexin, 35-37 cheap 750 mg cephalexin with mastercard. Its one drawback is the susceptibility of the etched surface to saliva or moisture contamination discount cephalexin 500mg with amex, which reduces the bond strength generic cephalexin 500 mg without a prescription. Salivary contamination results in significantly reduced bond strengths unless removed by thorough washing. Re-etching of the surface is usually necessary if salivary contamination has occurred. Bonding agents Bonding agents used as an additional layer under a resin sealant yield bond strengths significantly greater than the bond strength obtained when using sealant alone. Initial results of clinical trials also show increased retention of the sealant when an intermediate bond is used. New bonding techniques are proving to be less technique sensitive, with respect to moisture control than erstwhile procedures. The use of a bonding agent under a sealant on wet contaminated surfaces yields bond strengths equivalent to the bond strength obtained when sealant is bonded directly to clean etched enamel without contamination. Most of the data on the subject of using a bonding agent as part of the sealant procedure supports its use. Use of a bonding agent would tend to increase the time and cost of the sealant application but in cases where maintaining a dry surface is difficult or where there are areas of hypomineralization on the surface, it would have many advantages. Logically, combination of these technologies to achieve better penetration with less steps in the application sequence would be beneficial and there is some evidence already in the use of self-etching primer-adhesive systems. As yet, there has only been a 2-year follow-up but the early results are promising in relation to retention. Other studies have shown that there are concerns about micro-leakage compared with conventional acid etching. The big bonus of the self-etching primer-adhesive system is the speed with which the operator can apply it. In the application procedure for the Prompt-L-Pop system, the operator brushes the self-etching adhesive on to the surface; air thins it, and follows this by immediate placement of the sealant and polymerization. At present, therefore, there are conflicting views on these systems but with technology moving ever onwards it does seem likely that in the future it should be possible to achieve good etching and bonding with a simpler application method. Most clinicians will employ a resin-based sealant, because they have a good track record. Many clinical trials have demonstrated the effectiveness of resin sealants and there are several long-term studies, which show the benefits. Fifteen years after a single application, resin sealants have shown 28% complete retention of sealants and 35% partial retention on first permanent molars. Where researchers re-applied sealant to those surfaces that had deficient sealant as determined by yearly exams, 65% complete retention was obtained and only 13% of the surfaces had caries or restorations after 20 years. Retreatment Sealants placed in the first permanent molars in children of ages 6, 7, and 8 and in second permanent molars in children of ages 11 and 12 required more re-application than those placed in older teeth. If the clinician places fissure sealant in newly erupted teeth it is more likely to fail, but should still be placed as early as possible, because the teeth are more vulnerable to caries at this time. However, fluoride release occurs only for a very short time and at a very low level. Many studies over 2- 3-year periods have reported good retention but with a similar caries incidence to conventional sealant. Since the addition of fluoride to sealant resin does not have any detrimental effect it could certainly be used, but until the chemistry can be adapted to readily unlock the fluoride, the anti-cariogenicity cannot be attributed to the fluoride. Such cements have high levels of fluoride available for release but they suffer from the drawback of poor retention. Even with the very poor retention rates, sealing with glass ionomer does seem to infer some caries protective effect. This may be due to both the fluoride released by the glass ionomer and residual material retained in the bottom of the fissure, invisible to the naked eye. Hence, glass ionomers, used as sealants can be classed as a fissure sealant but more realistically as a fluoride depot material. They can be usefully employed to seal partially erupted molars in high risk children since eruption of the molars takes 12-18 months and during this time they are often very difficult to clean. They are also useful in children where there are difficulties with the level of co-operation, as the technique does not depend on absolute moisture control. As yet, studies of these materials used as fissure sealants while available, show no improvement over resin-based sealants and so there is nothing to recommend them in preference to resins. Retention is better for unfilled resins probably because it penetrates into the fissures more completely. If a filled resin is not adjusted there is a perceptible occlusal change, possible discomfort, and wear of the opposing antagonist tooth. It has been found that identification error for opaque resin was only 1% while for clear resin the corresponding figure was 23% with the most common error being false identification of the presence of clear resin on an untreated tooth. The disadvantage of opaque sealant is that the dentist cannot examine the fissure visually at future recalls (Figs. Safety issues There has only been one report of an allergy to the resin used for pit and fissure sealing and concern has been raised about the oestrogenicity of resin-based composites. The amount released orally is undetectable in the systemic circulation and concerns about potential oestrogenicity are probably unfounded. Sealant bulk in relation to application It is important to remember that the sealant must be kept to a minimum, consistent with the coverage of the complete fissure system including buccal and lingual pits. Sealant monitoring Once the sealant has been placed the operator must monitor it at recall appointments and repair or replenish as necessary. This leaves that surface equally at risk from caries compared to an unsealed surface. Cost-effectiveness Cost-effectiveness will depend on the caries rate for the children in the population. Where there is a higher caries rate, generalized sealing will protect more surfaces that would have become carious in the future. However, if the caries rate is very high, then the risk of developing interproximal lesions is also higher and may lead to a two surface restoration even when the fissure sealed surfaces remain caries free. Sealing over caries Once caries has been diagnosed it is important to determine its extent. If there is clear unequivocal evidence that the lesion does not extend beyond the enamel, then the surface may be sealed and monitored both clinically and radiologically. However, several authors have shown that dentinal carious lesions do not progress under intact sealants. Nevertheless, if the sealant were to fail immediately or shortly after application, then the lesion would have 4-6 months to progress before the next review. We do not advocate sealing over caries except in very exceptional circumstances, that is, very nervous children who cannot cope with even minimal intervention dentistry. Once the technique is mastered it can be applied both quickly and with minimal discomfort. It protects the soft tissues (tongue, cheeks, and gingivae) from damage from instruments or medicaments. It reduces the risk of swallowing and inhalation of instruments, and particles and debris. It makes the salivary aerosol produced by high speed rotary instruments easier to control thereby reducing the risk of infection to the dental staff. If used with inhalation sedation it will reduce the amount of mouth breathing thereby allowing less nitrous oxide to be used and thus reducing the gas level in the general environment of the dental surgery. It often makes the child feel isolated from the treatment, thus helping the child to feel more relaxed and able to cope. It provides the best possible dry field; for materials where moisture control is essential its use is imperative (Fig. Other texts give full details of the various application techniques of the rubber dam. It must be remembered that good analgesia is very important, as placement of rubber dam particularly when a clamp is used is painful.
The Ds that are farther into the tails of the distribution are less likely to occur if H0 was true and the therapy did not work generic 750 mg cephalexin amex. Computing the Related-Samples t-Test Computing tobt here is identical to computing the one-sample t-test discussed in Chapter 11—only the symbols have been changed from X to D There buy 750mg cephalexin mastercard, we first com- puted the estimated population variance 1s2 2 order cephalexin 750 mg amex, then the standard error of the mean 1s 2 order cheap cephalexin, X X and then tobt. First, find s2 , which is the estimated population variance of the difference scores. D The formula for s2 is D 1©D22 ©D2 2 2 N sD 5 N 2 1 (Note: For all computations in this t-test, N equals the number of difference scores. This is the standard error of the mean difference, or the “stan- dard deviation” of the sampling distribution of D. The formula for the related-samples t-test is D 2 D tobt 5 sD Here, D is the mean of your difference scores, sD is computed as above, and is the value given in H0: It is always zero (unless you are testing a nonzero difference). Then, as usual, tobt is like a z-score, indicating how far our D is from the D of the sampling distribution when measured in standard error units. Interpreting the Related-Samples t-Test Interpret tobt by comparing it to tcrit from the t-tables in Appendix C. The tobt is in the region of rejection, so the results are significant: Our sample with D 513. Therefore, we accept Ha, con- cluding that the sample represents a population of Ds having a D that is not zero, with D probably around 13. Because we have determined that this reduction is significant using D, we can also conclude that this reduction is significant using our original fear scores. Instead, we conclude that our therapy works, with the sample data representing a relationship in the population of spider-phobics such that fear scores go from a around 14. Then we’d want to have maximized our power in the same ways as discussed previously: We maximize the differences between the conditions, minimize the variability in the scores within the conditions, and maximize N. Note: A related-samples t-test is intrinsically more pow- erful than an independent-samples t-test because the Ds will be less variable than the original raw scores. Thus, by designing a study that uses related samples, we will tend to have greater power than when we design a similar study that uses independent samples. With significant results, we use the sample means to estimate the of the fear scores for each condition as described above. It would be nice to compute a confidence inter- val for each , as in the previous chapter, but we cannot do that. Statistical Hypotheses for the Related-Samples t-Test 277 Computing the Confidence Interval for D Because our D is 13. The confidence interval for D describes a range of values of D, one of which our sample mean is likely to represent. The formula for the confidence interval for D is 1sD212tcrit2 1 D # D # 1sD211tcrit2 1 D This is the same formula used in Chapter 11, except that the symbol X has been replaced by D. The tcrit is the two-tailed value for df 5 N 2 1, where N is the number of difference scores, sD is the standard error of the mean difference computed as above, and D is the mean of the difference scores. In other words, we would expect the average difference in before and after scores in the population to be between 0. Performing One-Tailed Tests with Related Samples As usual, we perform a one-tailed test when we predict the direction of the difference between our two conditions. Realistically, in the phobia study, we would predict we’d find lower scores in the after-therapy condition. Then to create Ha, first arbitrarily decide which condition to subtract from which and what the differences should be. We subtracted the predicted lower after-scores from the predicted higher before-scores, so this should produce Ds that are positive. Then locate the region of rejection based on your prediction: Our D should be positive and, as in Figure 12. Had we predicted higher scores in the after-therapy condition then, by subtracting before from after, the Ds and D should be negative, representing a negative D. Now the region of rejection is in the lower tail of the sampling distribution, and tcrit is negative. Compare tobt to tcrit: If tobt is beyond tcrit, the results are significant; describe the populations of raw scores and interpret the relationship. If tobt is not beyond tcrit, the results are not significant; make no conclusion about the relationship. Subtracting A – B, what are H0 and Ha if we pre- dicted that B would produce lower scores? If you stop after hypothesis testing, then you’ve found a relationship, but you have not described it. Instead, whenever (and only) when you have significant results, you should fully describe the relationship in your sample data. Notice that for the phobia study the means of the orig- inal fear scores from the before and after conditions are plotted, not the Ds. Further, recall that the regression line summarizes a relationship by running through the center of the scatterplot. Therefore, we can envision the scatterplot in each graph as being around the line, with participants’ data points located above and below each mean’s data point. Therefore, for participants in a particular condition, we travel vertically to the line and then horizontally to Y, predicting that they scored at the mean score for that condition. Likewise, some inde- pendent variables have a greater impact on a behavior than others. Measuring Effect Size in the Two-Sample Experiment An important statistic for describing the results of an experiment is called a measure of effect size. The “effect” is from cause and effect, because in an experiment we assume that changing the independent variable “causes” the dependent scores to change. Effect size indicates the amount of influence that changing the conditions of the independent variable had on dependent scores. Thus, for example, the extent to which changing hypnosis influ- enced recall scores is the effect size of hypnosis. The larger the effect size, the greater is the independent variable’s impact in deter- mining participants’ scores. We want to study those variables that most influence the behavior measured by these scores, so the larger the effect size, the more scientifi- cally important the independent variable is. Remember that significant does not mean important, but only that the sample relationship is unlikely to reflect sampling error. Although a relationship must be significant to be potentially important, it can be significant and still be unimportant. Thus, you should always compute a measure of effect size for any significant result, because this is the only way to determine whether your independent variable is important in influencing a behavior. In fact, the American Psychological Association requires published research to report effect size. Effect Size Using Cohen’s d One way to describe the impact of an independent variable is in terms of how big a difference we see between the means of our condi- tions. For example, we saw that the presence/absence of hypnosis produced a differ- ence in recall scores of 3. However, the problem is that we don’t know whether, in the grand scheme of things, 3 is large, small, or in between. We need a frame of reference, and here we use the estimated population standard deviation. Recall that the standard deviation reflects the “average” amount that scores differ from the mean and from Describing the Relationship in a Two-Sample Experiment 281 each other. Individual scores always differ much more than their means, but this still provides a frame of reference. For example, if individual scores differ by an “average” of 20, then we know that many large differences among scores occur in this situation. Therefore, a difference of 3 between two samples of such scores is not all that impres- sive. Because smaller differ- ences occur in this situation, a difference between conditions of 3 is more impressive.