A Simple and Low-cost Drilling Simulator for Training Plunging Distance Among Orthopedic Surgery Residents

OBJECTIVE

Drilling through bone is a complex action that requires precise motor skills of an orthopedic surgeon. In order to minimize plunging and soft tissue damage, the surgeon must halt drill progression precisely following penetration of the far cortex. The purpose of this study was to create a low-cost and easy-to-use drilling simulator to train orthopedic residents in reducing the drill plunging depth.

DESIGN, SETTING, PARTICIPANTS

This prospective observational study was performed in the division of orthopedic surgery of a single tertiary medical center. The participants included 13 residents and 7 orthopedic specialists. The simulator consisted of a synthetic femur bone model and ordinary modeling clay, and the training unit consisted of a disposable plastic tube (∼US$14), clamps (∼US$58), and a power drill + drill bit (standard hospital equipment). Plunging depths were measured by the simulator and compared between orthopedic specialists, the 6 "senior residents" (3+ years) and the 7 "junior residents" during a training session. Measurements were taken again 2 weeks following the training session.

RESULTS

Initially, the plunging depths of the junior residents were significantly greater compared to those of the orthopedic specialists (7.00 mm vs. 5.28 mm, respectively, p < 0.038). There was no similarly significant difference between the senior residents and the orthopedic experts ([6.33 mm vs. 5.28 mm, respectively; p = 0.18). The senior residents achieved plunging depths of 5.17 mm at the end of the training session and 4.7 mm 2 weeks later compared to 7.14 mm at the end of the training session and 6 mm 2 weeks later for the junior residents.

CONCLUSIONS

This study demonstrated the capability of a low-cost drilling simulator as a training model for reducing the plunging depth during the drilling of bone and soft tissue among junior and senior residents.

An Analysis of Bubble Deformation by a Sphere Relevant to the Measurements of Bubble-Particle Contact Interaction and Detachment Forces

Atomic force microscopy makes it possible to measure the interacting forces between individual colloidal particles and air bubbles, which can provide a measure of the particle hydrophobicity. To indicate the level of hydrophobicity of the particle, the contact angle can be calculated, assuming that no interfacial deformation occurs with the bubble retaining a spherical profile. Our experimental results obtained using a modified sphere tensiometry apparatus to detach submillimeter spherical particles show that deformation of the bubble interface does occur during particle detachment. We also develop a theoretical model to describe the equilibrium shape of the bubble meniscus at any given particle position, based on the minimization of the free energy of the system. The developed model allows us to analyze high-speed video captured during detachment. In the system model deformation of the bubble profile is accounted for by the incorporation of a Lagrange multiplier into both the Young-Laplace equation and the force balance. The solution of the bubble profile matched to the high-speed video allows us to accurately calculate the contact angle and determine the total force balance as a function of the contact point of the bubble on the particle surface.

Anchor suture fixation of distal pole fractures of patella: twenty seven cases and comparison to partial patellectomy

PURPOSE

Partial patellectomy (PP) and reattachment of the patellar ligament with transosseous suturing is the mainstay of surgical treatment for distal pole patellar fractures. An anchor suturing (AS) technique has recently been reported as an alternative to PP in such fractures and allows for bone-to-bone interface and possibly superior fracture healing than bone-to-tendon interface with PP. We present our experience with AS and compare it to PP.

METHODS

Between 2006 and 2011, 60 patients with distal pole patellar fracture underwent either AS (n = 27) or PP (n = 33). We retrospectively gathered their demographic data and information on fracture type, fixation technique, operation time, postoperative complications and knee range of motion. A telephone survey was performed to grade functional outcomes with standard questionnaires (the SF-12 for quality of life, the Kujala score for patellofemoral function and a visual analog scale [VAS] pain score).

RESULTS

AS was equivalent to PP in terms of residual pain and functional outcomes (VAS: 2.45 vs. 2.26, p = 0.83 and Kujala score: 74.3 vs. 69, p = 0.351, respectively) as well as for knee range of motion. Complications included three cases of infection in each group, two cases of early hardware failure and one case of non-union in the AS group. Operation time was significantly shorter for AS compared to PP (68.5 vs. 79.1 min, p = 0.03).

CONCLUSIONS

AS is non-inferior to PP for function and pain after distal pole patellar fractures and is superior to PP with regard to operative time. Common complications of this technique are hardware failure and infections.

LEVEL OF EVIDENCE

Therapeutic Level III.

Predictors for nonunion, reoperation and infection after surgical fixation of patellar fracture

INTRODUCTION

The most common major complications following surgical fixation of patellar fractures are infection, nonunion and reoperation. In this study, we sought to define the predisposing factors to the development of these complications.

METHODS

Open reduction and internal fixation surgeries for patellar fractures that were performed in a single institution between 2006 and 2011 were retrospectively reviewed. Patients' demographic data (age, gender, comorbidities), injury and fracture data (associated injuries, type of fracture, open or closed fracture), surgical data (type of surgery and interval between fracture occurrence and surgery) and major postoperative complications (infection, nonunion, symptomatic hardware and revision surgery) were collected from the medical records and verified by a telephone survey. Correlation analysis identified the major variables influencing the development of these complications.

RESULTS

The cohort of 188 patients had an average follow-up of 908 days. Thirteen (6.9 %) patients developed infection, 3 (1.6 %) had fracture nonunion and 42 (22.3 %) required a second operation. A history of cerebrovascular accident (CVA) correlated significantly with the development of infection (OR 6.18, CI 1.1-35.6, p = 0.041) and nonunion (OR 14.9, CI 1.2-188.1; p = 0.037). A history of diabetes significantly increased the risk of a second operation (OR 8.69, CI 95 % 1.8-41.9, p = 0.007). Open fracture did not increase the risk of any of these complications.

CONCLUSIONS

A history of CVA and diabetes mellitus significantly increased the risk of complications following patellar fracture fixation. Patients with these comorbidities should be informed of their increased risk of these complications and be followed up more rigorously.

The incidence of heterotopic ossification in hip arthroscopy

PURPOSE

The purpose of this study was to assess the incidence of heterotopic ossification (HO) after hip arthroscopy.

METHODS

Between July 2010 and July 2011, 83 patients underwent hip arthroscopy for various etiologies. We prospectively reviewed 50 consecutive hip arthroscopy procedures (31 male and 19 female patients; mean age, 36.7 years) with a mean follow-up of 29.56 weeks (range, 9 to 62 weeks) to assess the incidence of HO and its effect on function and clinical outcome. Preoperative and postoperative evaluation included general assessment by visual analog scoring, modified Harris Hip Score, Hip Outcome Score, and preoperative and postoperative radiographs. Heterotopic bone formation was assessed on radiographs at a minimum of 9 weeks from surgery with the Brooker classification.

RESULTS

Of the patients, 22 (44%) had radiographic evidence of postoperative HO (15 male patients): 13 (26%) had Brooker stage 1, 5 (10%) had Brooker stage 2, and 4 (8%) had Brooker stage 3. HO appeared as early as 9 weeks after surgery. No significant difference was found in demographic data, surgery-related data, or clinical and functional scores between patients with HO and patients without HO. No factor was found to significantly affect the incidence of HO after logistic regression. No distinct clinical manifestation was associated with the presence of HO.

CONCLUSIONS

This study shows that the incidence of HO after hip arthroscopy may be underestimated. We could not find a contributing factor to the formation of HO. Although in most cases the presence of HO will have minimal or no clinical and functional significance, it should be sought at a minimum of 9 weeks postoperatively.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Status of nonoperative management of blunt hepatic injuries in 1995: a multicenter experience with 404 patients

INTRODUCTION

Nonoperative management is presently considered the treatment modality of choice in over 50% of adult patients sustaining blunt hepatic trauma who meet inclusion criteria. A multicenter study was retrospectively undertaken to assess whether the combined experiences at level I trauma centers could validate the currently reported high success rate, low morbidity, and virtually nonexistent mortality associated with this approach. Thirteen level I trauma centers accrued 404 adult patients sustaining blunt hepatic injuries managed nonoperatively over the last 5 years. Seventy-two percent of the injuries resulted from motor vehicle crashes. The mean injury severity score for the entire group was 20.2 (range, 4-75), and the American Association for the Surgery of Trauma-computerized axial tomography scan grading was as follows: grade I, 19% (n = 76); grade II, 31% (n = 124); grade III, 36% (n = 146); grade IV, 10% (n = 42); and grade V, 4% (n = 16). There were 27 deaths (7%) in the series, with 59% directly related to head trauma. Only two deaths (0.4%) could be attributed to hepatic injury. Twenty-one (5%) complications were documented, with the most common being hemorrhage, occurring in 14 (3.5%). Only 3 (0.7%) of these 14 patients required surgical intervention, 6 were treated by transfusions alone (0.5 to 5 U), 4 underwent angio-embolization, and 1 was further observed. Other complications included 2 bilomas and 3 perihepatic abscesses (all drained percutaneously). Two small bowel injuries were initially missed (0.5%), and diagnosed 2 and 3 days after admission. Overall, 6 patients required operative intervention: 3 for hemorrhage, 2 for missed enteric injuries, and 1 for persistent sepsis after unsuccessful percutaneous drainage. Average length of stay was 13 days. Nonoperative management of blunt hepatic injuries is clearly the treatment modality of choice in hemodynamically stable patients, irrespective of grade of injury or degree of hemoperitoneum. Current data would suggest that 50 to 80% (47% in this series) of all adult patients with blunt hepatic injuries are candidates for this form of therapy. Exactly 98.5% of patients analyzed in this study successfully avoided operative intervention. Bleeding complications are infrequently encountered (3.5%) and can often be managed nonoperatively. Although grades IV and V injuries composed 14% of the series, they represented 66.6% of the patients requiring operative intervention and thus merit constant re-evaluation and close observation in critical care units. The optimal time for follow-up computerized axial tomography scanning seems to be within 7 to 10 days after injury.

Abdominal stab wound protocol: prospective study documents applicability for widespread use

Traditionally, stab wounds violating the abdominal wall fascia led to exploratory celiotomy that was often nontherapeutic. In an attempt to limit the number of nontherapeutic celiotomies (NTC), we devised a protocol to prospectively study stab wounds violating the anterior abdominal wall fascia. Through protocol, abdominal stab wounds were explored in stable adults. If the anterior fascia was violated, paracentesis and, if necessary, peritoneal lavage was undertaken in the absence of previous abdominal surgery. If evisceration was noted, it was reduced and the patient lavaged. Fascial penetration was noted in 72 patients. 46 patients underwent celiotomy: because of shock/peritonitis in 8 (2 NTC), fascial penetration with a history of previous celiotomy in 7 (5 NTC), positive paracentesis in 20 (5 NTC), or positive lavage in 10 (4 NTC). One patient underwent late celiotomy without ill-effect after a negative lavage because she subsequently developed fever and localized peritonitis (ice pick injury to cecum). Eleven patients had evisceration; nine underwent celiotomy. Patients with abdominal stab wounds can be selectively managed safely. More than one-third with fascial penetration, some with evisceration, avoided exploration. Only one patient underwent delayed celiotomy and did so without detriment. Nontherapeutic celiotomy rates were highest in patients with previous abdominal surgery who, thereby, could not undergo paracentesis/lavage; excluding these patients, the nontherapeutic celiotomy rate was 17% (11/65) for those with fascial penetration.

Intestinal and hepatic apolipoprotein B gene expression in abetalipoproteinemia

A 20-year-old woman with abetalipoproteinemia underwent orthotopic liver transplantation for cirrhosis, affording access to her liver and small intestine for study. Before transplantation, her plasma apolipoprotein B concentration was less than 1 mg/dL according to enzyme-linked immunosorbent assay, whereas after transplantation her plasma apolipoprotein B concentration was 76 mg/dL (all apolipoprotein B-100). Apolipoprotein B content was reduced in her intestine and liver compared with normal and cirrhotic controls. Cultured hepatocytes from the patient's explanted liver secreted a 1.006 g/mL less than or equal to d less than or equal to 1.063 g/mL lipoprotein rich in apolipoprotein E and a 1.063 g/mL less than or equal to d less than or equal to 1.21 g/mL lipoprotein containing apolipoproteins E and A-I with no immunodetectable apolipoprotein B in the culture medium. Normal hepatocytes secreted very low-density lipoprotein and low-density lipoprotein containing apolipoprotein B-100. Abetalipoproteinemic intestinal apolipoprotein B messenger RNA concentration was 4-5-fold higher than control values. However, the patient's liver apolipoprotein B messenger RNA level was one fifth that of control normal and cirrhotic liver. Analysis of the patient's intestinal and hepatic apolipoprotein B messenger RNA for posttranscriptional stop-codon insertion revealed normally edited transcripts. These results suggest that apolipoprotein B is synthesized as the product of a normally edited messenger RNA transcript, but not secreted, in abetalipoproteinemia.

Biogenesis of plasma lipoproteins in rat hepatoma McA-RH7777: importance of diffusion-mediated events during cell growth

Cultured McA-RH7777 rat hepatoma cells actively synthesize and secrete plasma lipoproteins. However, synthesis of [14C]triglyceride declines monotonically throughout the early growth period and remains low in postconfluent cultures; and net secretion of [14C]triglyceride is 10-fold more efficient in logarithmically growing cultures than in postconfluent cultures. Secretion of apolipoproteins associated with very low density and low density lipoproteins is selectively reduced in postconfluent cultures. The temporal reductions in [14C]triglyceride production are related more strongly to increasing cell concentration (cells/cm3 medium) than to increasing cell density (cells/cm2 growth surface). We have allowed cells to grow either retained within small circular corrals or unrestricted in culture dishes. When seeded at equal density (10(4) cells/cm2) but at one-fifth the cell concentration, corralled cells synthesize twice as much [14C]triglyceride per cell after 2 and 4 d, and are 10 times as efficient in [14C]triglyceride secretion by 6 d of growth, as noncorralled cells. When seeded at equal cell concentration (10(5) cells/dish) but at 5 times the cell density, corralled cells are only 20% less efficient at [14C]triglyceride synthesis and secretion than noncorralled cells. Conditioned medium depresses synthesis and secretion efficiency of [14C]triglyceride. Orotic acid exposure also inhibits synthesis of [14C]triglyceride and secretion of certain [35S]apolipoproteins in early cultures, but it has no significant effect on late cultures. We conclude that diffusion-mediated events are important regulators of triglyceride and apolipoprotein production in growing rat hepatoma cells, but that events associated with formation of cell-to-cell contacts play a minor role in regulation of plasma lipoprotein biogenesis.

Gastric pseudolymphoma and its relationship to malignant gastric lymphoma

Gastric pseudolymphoma is generally considered a benign, reactive condition to chronic inflammation. We report a patient who, although initially diagnosed as having a gastric pseudolymphoma, was found to have a malignant gastric lymphoma 5 yr later. A review of the literature revealed 12 previously reported cases in which gastric pseudolymphoma was associated with a malignant gastric lymphoma. The premalignant nature of gastric pseudolymphoma is discussed, and frequent endoscopic surveillance to exclude transition to malignant lymphoma is recommended.

Correlates of cardiac and sudden death after ambulatory monitoring in a community hospital. Importance of clinical characteristics, congestive heart failure and tachyarrhythmias

To analyze the prognostic importance of arrhythmias on routine 24-hour ambulatory monitoring, we prospectively followed 755 consecutive patients undergoing monitoring at a community hospital in the context of usual medical care. Of the 755 patients, 114 (15%) had ventricular tachycardia on monitoring. At a mean follow-up of 38 months, multivariate survival analysis indicated that congestive heart failure was the strongest correlate of death from all causes (relative risk (RR) = 2.6), cardiac death (RR = 3.5), and the sudden cardiac death (RR = 5.6); ventricular tachycardia was significantly correlated with death from all causes and with cardiac death, but had only a borderline association with sudden cardiac death (RR = 1.9, p = 0.08). While ventricular tachycardia on ambulatory monitoring is of prognostic importance, congestive heart failure, as determined by routine clinical examination, was a more powerful prognostic correlate of deaths from all causes, death from cardiac causes, and sudden cardiac death.

Benefits of experience. Treating coronary artery disease

The authors examined the issue of learning by doing in terms of both the cost and outcome of treating coronary artery disease at one hospital between 1977 and 1981. Over time, the quality of outcome improved for both medical and surgical patients. During this time of cost-plus reimbursement, there was less conclusive evidence of concurrent technical efficiency gains. These findings are consistent with the hypothesis that the benefits of experience can be substantial but they do not just happen: they require proper provider motivation.

Acute and subchronic toxicity of dimethylformamide and dimethylacetamide following various routes of administration

Dimethylformamide (DMF, CAS No. 68-12-2) and dimethylacetamide (DMAC, CAS No. 127-19-5) are widely used for their superior solvent properties. A series of single and multiple dose experiments in rodents were conducted to determine the target organs, and to establish doses which, under various routes of administration, produced those changes. DMF produced moderate irritation in the rabbit eye, with the corneal response clearing in 2 to 4 weeks. DMAC produced only mild, quickly reversible conjunctival irritation. Oral doses of DMF to the rat of 2,250 mg/kg or greater produced lethality which was associated with liver damage. Lethality occurred following oral doses of 4,500 mg/kg DMAC with LD50's for male and female rats of 5,809 and 4,930 mg/kg, respectively. The 1 hour LC50 by inhalation for DMAC in the rat was 2,475 ppm or greater. Sensory irritation was produced in the mouse at concentrations of 1,658 ppm or greater for DMF. Repeated oral doses of 450 mg DMF/kg to rats produced reduced body weight gain and liver injury with both changes being reversible. DMAC tested similarly produced body weight effects, liver injury, and testicular changes in the rat with all changes again being readily reversible. Dermal doses of 2,000 mg/kg of either DMF or DMAC were poorly tolerated by rabbits. DMAC was slightly more toxic with all treated rabbits dying of acute hepatic necrosis. Repeated inhalation of 2,000-2,500 ppm produced mortality in rats exposed to DMF but not DMAC. Liver injury was seen with DMF, testicular changes with DMAC. DMF and DMAC both produced slight anemia and leukocytosis in rats during 90 days of feeding. Liver weights were elevated in rats fed DMF, but not DMAC, at a level of 1,000 ppm. The "no-observed effect level" in rats fed DMF for 90 days was 200 ppm. The overall toxicologic profiles of both DMAC and DMF are similar with the target organ being the liver.

Comparative costs versus symptomatic and employment benefits of medical and surgical treatment of stable angina pectoris

For patients who underwent cardiac catheterization for stable angina pectoris at the authors' hospital, initial treatment charges including the cardiac catheterization were approximately $28,000 for coronary surgery and $6,000 for medical therapy. Even after controlling for disease severity and after including medical patients who crossed over to surgery, the slightly increased 3-year follow-up costs of medical therapy offset only approximately 11% of the far higher initial costs of surgery. Surgical patients were more likely to have sustained, substantial symptomatic improvement at 3 years (68% vs. 53%, P less than 0.05) but were no more likely to have, maintain, or regain a job. Although the cost-effectiveness of coronary surgery may compare favorably with other modern therapies for other conditions, coronary surgery did not pay for itself at 3-year follow-up in our patients.

Gonorrhea case-finding among asymptomatic men seeking ambulatory care: a cost effectiveness analysis

Case-finding for gonorrhea in asymptomatic men is generally not performed in primary care settings and often not performed when men are seen for other reasons in clinics for sexually transmitted diseases. We performed a cost-effectiveness analysis of case-finding among asymptomatic men seeking ambulatory care, using culture of the first-voided urine and treatment of culture-positive patients with tetracycline. The analysis demonstrated that care-finding is increasingly cost-effective as the probability of asymptomatic gonorrhea becomes greater. Over a reasonable expected range of the probability of asymptomatic gonorrhea (0.1-15%) in such settings, the additional cost to avert one additional day of morbidity ranged from $47,000 to $260; the additional cost to avert one additional case of residual asymptomatic infection ranged from $26,000 to $140; and the additional cost to avert one additional case of pelvic inflammatory disease in a contact ranged from $250,000 to $1,400. We conclude that the cost-effectiveness of case-finding for gonorrhea among asymptomatic men compares favorably with that of other medical interventions when the probability of infection is relatively high (perhaps greater than or equal to 5%). In order to make use of such information, physicians in ambulatory care settings require better information about the probability of gonorrhea in asymptomatic men who differ in their medical histories and socioeconomic and ethnic backgrounds.

The selective impact of a cardiology data bank on physicians' therapeutic recommendations

We asked the physicians and medical students caring for 60 patients with symptomatic coronary artery disease, immediately after reviewing cardiac catheterization data, to choose medical or surgical therapy and to estimate prognosis one and three years after either therapy. The next day, each participant was given prognostic estimates generated from a large coronary artery disease data bank and again asked to estimate prognosis and choose therapy. Participants unanimously chose medicine for 20 patients (Group I) and surgery for 21 patients (Group III). For 19 patients (Group II), participants were divided on their choice of therapy. After seeing data bank estimates, participants rarely changed recommendations for Group I or Group III, but changed ten percent (9/90, p less than 0.01) of their Group II recommendations. Changes of recommendations by far (9/12, p = 0.02) favored medicine, causing the majority recommendation to change to medicine for two Group II patients. Therapeutic recommendations were guided mostly by pathoanatomy and the chance of improving medical regimens. Computer-generated prognostic data selectively influenced choices among the Group II cases where recommendations had been divided, resulting in changes toward less costly therapy.

Surveillance effects on community physician test ordering

The announcement that orders for long-term electrocardiograms were the subject of study in a community hospital was followed by a decrease in ordering rate of 30% from the corresponding quarter in the previous year. In succeeding quarters the decrement from corresponding quarters in the prior year was 21%, 27%, and 6%. Thereafter the ordering rate began to increase at a rate of 75% per year. In another community hospital in a contiguous town in which no surveillance was undertaken, the ordering rate for long-term electrocardiogram grew persistently at the rate of 42% per year over the same 3-year interval. The cardiologists at the community hospital under study behaved no differently as a group than other physicians in the community. The data strongly suggest that announced surveillance had the effect of diminishing long-term electrocardiogram tests ordered by community physicians by at least 20% for a period that lasts up to 9 months.

Clinical utility and management impact of M-mode echocardiography

To determine the clinical utility and management impact of M-mode echocardiography, 182 echocardiograms were analyzed at a university teaching hospital. The physicians who ordered the echocardiograms said that 12 percent provided crucial information that was not available from other tests and that 26 percent resulted in a change in patient management. According to two independent board-certified cardiologist-reviewers, 86 percent of echocardiograms were appropriately ordered, but only 15 echocardiograms (8 percent) were actually needed for a change to a new and appropriate management. According to the reviewers, the 77 Group I M-mode echocardiograms (those ordered to evaluate left ventricular function, left atrial size, potential cardiac sources of emboli, or the possibility of bacterial endocarditis, or those ordered in patients who, according to the ordering physician, had undergone or would undergo catheterization regardless of the results of echocardiography) were less likely than the 105 Group II M-mode echocardiograms (those ordered to evaluate possible mitral valve prolapse, hypertrophic cardiomyopathy, valvular function, or the pericardium) to be ordered appropriately, to provide helpful information, or to provide crucial results. Group I echocardiograms had reviewer-assessed appropriate management impact in only one case (1 percent) compared with a 13 percent rate of management impact for Group II M-mode echocardiograms (p less than 0.01). Although echocardiography can be accurate and valuable with yields similar to those of other noninvasive procedures, 77 (42 percent) of 182 M-mode echocardiograms in this hospital could be predicted at the time of ordering to be in a low-yield group.

Incremental value of the exercise test for diagnosing the presence or absence of coronary artery disease

To determine the incremental value of the exercise test (ETT) for diagnosing coronary artery disease (CAD), we derived a multivariate logistic regression model for the pre-ETT prediction of CAD using data from 3840 patients at Duke University. We then applied the model to 324 patients at the Brigham and Women's Hospital. Using seven clinical factors, the multivariate model had an 84% overall predictive accuracy on both the training (Duke) and the validation (Brigham) sets of patients. Three ETT factors (ST-segment change in patients not taking digitalis, absence of ST-segment change in patients taking digitalis, ETT stopped because of ECG or blood pressure changes) had incremental, significant predictive power, but overall predictive accuracy based on both clinical and ETT factors improved only to 87%. When the ETT result was important enough to move the probability of CAD across a potential therapeutic threshold, the direction of the change in probability was correct only two-thirds of the time. Thus, the ETT was of limited value in predicting the presence or absence of CAD after other easily obtainable clinical data were taken into account.

Urethritis in men: benefits, risks, and costs of alternative strategies of management

Four alternative strategies for the management of men with acute urethritis were analyzed: treating patients with tetracycline, with or without a urethral culture, without basing the initial treatment decision on the results of a gram-stained smear; treating patients with penicillin, without basing initial treatment on the results of a gram-stained smear; basing initial treatment with tetracycline or penicillin on the results of a gram-stained smear; and basing treatment on the results of both a gram-stained smear and a culture. The tetracycline strategy resulted in fewer days of morbidity, a lower probability of premature death, lower dollar costs, and a much lower rate of uncured nongonococcal urethritis, but in slightly higher rates of uncured gonorrhea and syphilis than more traditional strategies. Use of culture with the tetracycline strategy (1A) permitted tracing of gonorrhea contacts, achieved the same low morbidity, and added little cost. The conclusions were true regardless of the probability of gonorrhea and for reasonable estimates of probable compliance with oral medication regimens. Test-of-cure cultures for patients who were asymptomatic after treatment for gonorrhea required the expenditure of from $4,900 to $109,800 for each case of asymptomatic persistent gonorrhea discovered and cured, depending on the strategy used.

Pitfalls in the serial assessment of cardiac functional status. How a reduction in "ordinary" activity may reduce the apparent degree of cardiac compromise and give a misleading impression of improvement

Because the New York Heart Association (NYHA) classification system categorizes patients based on subjective impression of the degree of functional compromise, a reduction in exercise might make a patient seem improved because the new lower level of ordinary activity produced fewer symptoms. To test this hypothesis, we studied three different sets of patients and compared their NYHA classes to their functional classes as determined by a new Specific Activity Scale (SAS) that is based on the metabolic equivalents of oxygen consumption required for activities the patient actually performs. Among ambulatory patients referred for exercise tests, the NYHA class was higher (i.e. indicated the patient was more limited) in 28% of patients and the SAS class was higher in 14% (p less than 0.001). Among patients interviewed at or near the time of catheterization for chest pain, the NYHA was higher in 20% and the SAS class was higher in 20% (p = NS). In both medically and surgically treated patients interviewed 1--3 yr after cardiac catheterization, the NYHA class was higher in only 4%, whereas the SAS class was higher in 28% (p less than 0.001). The SAS class was significantly more likely to be higher in patients who were not working full time and in patients who described their present activity level as sedentary or light. When the NYHA and SAS systems disagreed as to whether a patient was improved, SAS was significantly more likely to correlate with the patient's self-assessment. These findings suggest that some patients restrict their activity as their cardiac disease progresses; the resultant change in the definition of ordinary activity may reduce the apparent degree of cardiac compromise and thus give a false impression of improvement by NYHA criteria.

Exponential increase in age-specific prevalence of ventricular dysrhythmia among males

Analyzing nine available studies of cardiac dysrhythmia among males shows an exponential increase of the prevalence of dysrhythmia with increased age (16-74 yr). This pattern appears in unselected populations and in populations selected for prior history of myocardial infarction. In 6 of 9 population groups the exponent for the rate of increased prevalence of any ventricular premature contractions (VPCs) with age was statistically indistinguishable from study to study despite variations in length of monitoring, of local interpretations of ECG, or of differences in the composition of these groups. Within each population group the prevalence of "frequent" VPCs or of "complex" VPCs also increased exponentially with age. The precise mathematical expression for the increase suggests an etiologic explanation for cardiac dysrhythmia common to coronary artery disease and myocardial infarctions which exhibit similar behavior.

Impact of a cardiology data bank on physicians' prognostic estimates. Evidence that cardiology fellows change their estimates to become as accurate as the faculty

To determine whether physicians would be influenced by the prognostic information in a large coronary artery disease data bank, cardiology faculty and fellows made initial estimates of the prognoses of their patients and then made revised final estimates after seeing the outcome of matched patients (OMP) from the data bank. The faculty cardiologists' original estimates proved to be as accurate as those of the data bank's OMP, and the faculty revised their estimates minimally in response to the data bank's OMP. Conversely, the cardiology fellows' original estimates were less accurate than the data bank's OMP, and under all observed circumstances the fellows responded more to the data bank's OMP than did the faculty. As a result, the accuracy of the fellows' final estimates was similar to the accuracies of both the faculty cardiologists and the data bank's OMP. Computerized data banks seem more likely to have impact when their information is provided to physicians who are relatively inexperienced with the disease in question.

Dissecting the hospital stay: a method for studying patient staging in hospitals

A methodology is proposed and tested for the staging of patients thorugh a hospital stay. Measurements in a university-affiliated hospital and a community hospital in the Boston area showed similar staging patterns with about half of the sample having abnormal signs and symptoms while under treatment. The second-largest sample group in both hospitals, consisting of 11% of the sample, occupied beds although ready for discharge. The methodology indicated those patient-time units in the hospital which might be amenable to further reduction and gave upper bounds on that compression. Contrary to prior expectations, 90% of the patients sampled followed a well-defined sequence from admission to discharge with only 10% having complications of the admitting diagnosis, new diagnosis or iatrogenic illness.

Liver and urinary bladder tumors in dogs from 3,3'-dichlorobenzidine

Six female beagle dogs were given, by capsule, a daily oral dose of 100 mg of 3,3'-dichlorobenzidine (DCB), 3 times per week for 6 weeks, then 5 times per week continuously for periods up to 7.1 years. The DCB test was terminated after 7.1 years. Six untreated female beagle dogs served as controls for several tests and were sacrificed after 8.3 to 9.0 years on test. All 6 DCB dogs had an elevated plasma glutamic-pyruvic transaminase activity during the first 3 years on test; two dogs showed persistent elevation throughout the test. One DCB dog, sacrificed in extremis after 3.5 years on test, had no tumors. Another DCB dog, sacrificed in extremis after 6.6 years on test, developed an undifferentiated carcinoma of the liver with metastases to many organs; this dog also had a papillary transitional cell carcinoma of the urinary bladder. Of the 4 remaining DCB dogs sacrificed after 7.1 years on test, 3 developed hepatocellular carcinomas and all 4 had papillary transitional cell carcinomas of the urinary bladder. No liver or urinary bladder tumors were found in the 6 control dogs. DCB was found to be carcinogenic for the liver and urinary bladder in dogs under the conditions employed (p less than .025, Fisher's Exact Test, one tail).

Protocols in ambulatory care

Protocols offer a mechanism for bringing together two major trends in outpatient care. The first trend is the delegation of certain clinical tasks and responsibilities to health workers other than physicians, and to patients themselves. The second trend is the movement toward standard-setting, peer review, audit and quality assurance, and cost-effectiveness of medical practices. Most of the studies of the use of protocols have been with nurse practitioners, physician assistants, office nurses, and health workers. These studies indicate that non-physicians using protocols - in comparison with physicians using traditional methods - give care that is equally thorough, and that leads to comparably accurate diagnosis treatment, and appropriate referral to physicians. Additionally, health workers guided by protocols achieve relief of patients; symptoms and patient satisfaction, and provide care that is efficient in terms of practitioner time, medication, and test ordering. Consequently, health workers using protocols can reduce the cost of care. Protocols have been developed for use in out-patient areas in both developed and developing nations. Protocosl can also be easily audited as part of a quality assurance program, effecting even further saving in costly provider time.

Kidney and liver tumors in rats from 4,4'-methylene bis (2-carbomethoxyaniline)

4,4'-Methylene bis (2-carbomethoxyaniline), also known as methylene-bis methyl anthranilate (MBMA), was added to the diet of male and female ChR-CD rats for up to two years at levels of 0, 1500, and 15,000 ppm. Fifty rats of each sex were used at each dietary level. Female rats at both dietary levels of MBMA had a lower body weight gain and lower food efficiency values than did the controls. High-level males and females showed a slight anemia; all other clinical laboratory tests were within normal limits. MBMA caused slight degenerative histologic changes in the liver and kidney of both sexes at both dietary levels. High-level males developed a statistically significant increase in kidney and liver tumors when compared to controls (p less than 0.05, Fisher's Exact Test, one tail). High-level females had an elevated kidney tumor incidence compared with controls (p less than 0.10). There was a statistically significant lower incidence in pituitary tumors in high-level males (p less than 0.05) and in high-level females (p less than 0.10) than in controls. High-level females had a lower incidence of mammary tumors (p less than 0.05) compared to controls. MBMA was considered to be a carcinogen of moderate potency in rats, since tumors were not found until 18 months on test using a comparative large dose (1.5% of diet).

Liver and lung tumors in dogs from 4,4'-methylene-bis(2-methylaniline)

Six female beagle dogs were given, by capsule, a daily dose of 100 mg 4,4'-methylene-bis(2-methylaniline) (MeMDA), 3 times per week for 6 weeks, then 5 times per week for 5 weeks, at which time the dose was reduced to 50 mg 5 times per week, continuously for periods up to 7.0 years. Six female beagle dogs were kept as untreated controls for several studies and were sacrificed after 8.3 to 9 years test. MeMDA dogs developed renal atrophy with an elevated blood urea nitrogen during an approximate six-month period prior to death or being sacrificed in extremis. As three of three MeMDA dogs that survived for 5.2 years to 7.0 years developed hepatocellular carcinomas and two of the three dogs also developed primary lung tumors, with no liver or lung tumor in six control dogs, MeMDA was considered to be carcinogenic for the dog (liver tumors: p less than .05; lung tumors: p less than 10; Fisher's Exact Test, one tail).

Toxicological evaluations of some brominated biphenyls

Extensive toxicological studies were carried out to define the probable hazard of octabromobiphenyl (OBB) to workers, users, and the environment. OBB had low acute toxicity in mammals and birds by various routes of administration. It was essentially non-irritating to rabbit eyes, non-irritating to human skin and caused only mild skin irritation and no sensitization in the guinea pig. OBB caused equivocal effects in the rat fetus. OBB was stored in the body fat of rats and caused liver enlargement at high single doses or low repeated doses. The studies indicate probable low safety factors in application and use and probable bioaccumulation. Hexabromobiphenyl (HBB) was more acutely toxic than OBB by skin absorption in the rabbit and caused liver enlargement at lower single doses.

Ambulatory care protocols as management tools

While a protocol is generally used by a physician, it is important for the manager to understand its use in monitoring costs and in assuring conformance with defined optimal standards of care.

Conservation in hospital resource use: treatment of pneumonias. An investigation of care in four hospitals over the past decade

An investigation of patient care in four hospitals compared levels of resource use between 1964 and 1974 for patients with a primary diagnosis of pneumonia. Results showed a decreased length of stay in all hospitals. Unique patterns of increases and decreases existed in each hospital for the changing use of diagnostic and therapeutic resources. Reduction in dollar value of length of stay was larger in all cases than increases in dollar value of diagnostic and therapeutic resource use. This resulted in an overall reduction in hospital resource charges over the decade, when 1974 dollar values were used. Large increases in diagnostic or therapeutic resources (up to 217%) were reflected as only minor increases in the partial hospital bill over the decade ( less than 11%). Increased intensity of resource use has contributed to increasing per-day charges of up to 27%, in the face of recent average cost rises of more than 10 times that size for daily hospital expenses.

Quality, efficiency, and cost of a physician-assistant-protocol system for managment of diabetes and hypertension

Briefly trained physicians assistants using protocols (clinical algorithms) for diabetes, hypertension, and related chronic arteriosclerotic and hypertensive heart disease abstrated information from the medical record and obtained history and physical examination data on every patient-visit to a city hospital chronic disease clinic over a 18-month period. The care rendered by the protocol system was compared with care rendered by a "traditional" system in the same clinic in which physicians delegated few clinical tasks. Increased thoroughness in collecting clinical data in the protocol system led to an increase in the recognition of new pathology. Outcome criteria reflected equivalent quality of care in both groups. Efficiency time-motion studies demonstrated a 20 per cent saving in physician time with the protocol system. Coct estimates, based on the time spent with patients by various providers and on the laboratory-test-ordering patterns, demonstrated equivalent costs of the two systems, given optimal staffing patterns. Laboratory tests were a major element of the cost of patient care,and the clinical yield per unit cost of different tests varied widely.