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Biomedical subjects

M E Charlson

Publications and source records attributed to M E Charlson.

At least 19 recordsLinked to original sources

Supervised fitness walking in patients with osteoarthritis of the knee. A randomized, controlled trial.

OBJECTIVE: To assess the effect of a program of supervised fitness walking and patient education on functional status, pain, and use of medication in patients with osteoarthritis of the knee. DESIGN: An 8-week randomized, controlled trial. SETTING: Inpatient and outpatient services of an orthopedic hospital in an academic medical center. PATIENTS: A total of 102 patients with a documented diagnosis of primary osteoarthritis of one or both knees participated in the study. Data were obtained on 47 of 51 intervention patients and 45 of 51 control patients. INTERVENTIONS: An 8-week program of supervised fitness walking and patient education or standard routine medical care. MEASUREMENTS: Patients were evaluated and outcomes assessed before and after the intervention using a 6-minute test of walking distance and scores on the physical activity, arthritis impact, pain, and medication subscales of the Arthritis Impact Measurement Scale (AIMS). RESULTS: Patients randomly assigned to the walking program had a 70-meter increase in walking distance relative to their baseline assessment, which represents an improvement of 18.4% (95% Cl, 9.8% to 27.0%). In contrast, controls showed a 17-meter decrease in walking distance relative to their baseline assessment (P less than 0.001). Improvements in functional status as measured by the AIMS physical activity subscale were also observed in the walking group but not in the control group (P less than 0.001); patients assigned to the walking program improved 39% (Cl, 15.6% to 60.4%). Although changes in scores on the arthritis impact subscale were similar in the two groups (P = 0.093), the walking group experienced a decrease in arthritis pain of 27% (Cl, 9.6% to 41.4%) (P = 0.003). Medication use was less frequent in the walking group than in the control group at the post-test (P = 0.08). CONCLUSIONS: A program of supervised fitness walking and patient education can improve functional status without worsening pain or exacerbating arthritis-related symptoms in patients with osteoarthritis of the knee.

Adult

Using faculty consensus to develop and implement a medical ethics course.

This report describes the development and implementation of a new required course in medical ethics for second-year medical students at the Cornell University Medical College, 1988-89 and 1989-90. The course was specifically designed to teach students who had not yet started their clinical clerkships to think critically and systematically about ethical issues faced by practicing physicians. The goals, structure, and content of the course were developed using an innovative technique, a planning model involving faculty consensus. The faculty members found the planning sessions intellectually challenging and enjoyable, and reported that the sessions added greatly to their teaching of the course. The students' evaluations over the first two years of the course (with 188 of the 201 students--94%--responding) documented the students' satisfaction with the content and the structure of the course, and their belief that the course had achieved its goals. The authors conclude that the faculty's participation in the planning process was crucial to the success of the course.

Consensus

Health services research in arthritis musculoskeletal disease.

This paper reviews recent studies in national patterns of disability related to arthritis, longitudinal studies of outcome in arthritis, the effects of the prospective payment system on outcomes of hip fracture patients, and recent studies of geographic variation in treatment of arthritis and musculoskeletal disease. It also reviews recent papers on clinimetric issues and advances in measuring disease activity.

Arthritis

Post-operative delirium: predictors and prognosis in elderly orthopedic patients.

OBJECTIVE: To compare the effect of post-operative analgesia using epidural versus intravenous infusions on the incidence of delirium after bilateral knee replacement surgery in elderly patients. Additional risk factors and impact on post-operative recovery were also assessed. DESIGN: Prospective randomized controlled trial. SETTING: Urban referral hospital specializing in elective orthopedic surgery. PATIENTS: 60 consecutive patients undergoing bilateral knee replacement surgery with epidural anesthesia were approached; 51 patients were eligible and consented. The mean age was 68, 55% were women, and there was a high prevalence of comorbid medical disease. No patient was demented pre-operatively. INTERVENTION: Random allocation to either continuous epidural infusion of bupivacaine and fentanyl or continuous intravenous infusion of fentanyl. Infusions were initiated at the first complaint of pain and continued through the 36- to 48-hour stay in the recovery room. MAIN OUTCOME MEASURE: Acute post-operative delirium defined using an algorithm based on DSM III criteria. RESULTS: The overall incidence of acute delirium was 41%, with no difference between types of post-operative analgesia. Predictors of delirium were age, gender, and pre-operative alcohol use. All cases resolved within 1 week, and length of stay and achievement of physical therapy goals were the same for delirious and non-delirious patients. CONCLUSIONS: There is a high incidence of post-operative delirium in elderly non-demented patients following bilateral knee replacement, regardless of whether post-operative analgesia is administered by the epidural or intravenous route.

Age Factors

Geographic variations in the rates of elective total hip and knee arthroplasties among Medicare beneficiaries in the United States.

We analyzed the variations in the rates of elective total hip and total knee arthroplasties for 1988 in the United States to determine whether the rates correlated with the numbers of surgeons. There were 56,204 total hip arthroplasties and 68,491 total knee arthroplasties, performed in the home states of the patients among all of the Medicare beneficiaries. Medicare beneficiaries include most people who are more than sixty-five years old in the United States and a small proportion of younger people who are eligible for Medicare for other reasons. Seventy-nine per cent of the patients who had had a total hip arthroplasty and 89 per cent of those who had had a total knee arthroplasty had been managed with the operation because of osteoarthrosis. Both operations were most common in the seventy to seventy-four-year age-group. We calculated the rate of operations per 100 beneficiaries for each state and age-adjusted the results. Across all of the states, bilateral procedures constituted 1.6 per cent of the total hip arthroplasties and 4.8 per cent of the total knee arthroplasties. The in-hospital rates of mortality were 0.72 per cent for total hip arthroplasties and 0.45 per cent for total knee arthroplasties. The destinations after discharge from the hospital were similar for the two groups of patients, with more than 65 per cent of the patients being discharged directly to their homes. There were no significant differences among states in terms of the length of stay in the hospital or reimbursement of the hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

A self-administered hip-rating questionnaire for the assessment of outcome after total hip replacement.

The hip-rating questionnaire was developed for the assessment of the outcome of total hip replacement. The purpose of this study was to evaluate its reproducibility, validity, and responsiveness. The questionnaire uses a 100-point scale in which equal weight is given to the domains of global or over-all impact of arthritis, pain, walking, and function. Ninety-eight patients were enrolled in the prospective study and have been followed for at least three months; sixty-two patients have been followed for six months; and forty-two patients have been followed for one year. Reproducibility was tested with the use of the kappa statistic in fifty patients whose condition was stable clinically, and it was found to be good or excellent both for individual questions and for the total score. The validity of the questionnaire was assessed by comparison with the scores from a six-minute walking-distance test and arthritis impact-measurement scales. The result of the six-minute walking-distance test correlated with the patient's response concerning walking distance on the hip-rating questionnaire. The score for pain from the hip-rating questionnaire correlated well with the score for pain from the arthritis impact-measurement scales, and the total score from the hip-rating questionnaire correlated well with the total score from the arthritis impact-measurement scales. The score on the hip-rating questionnaire was responsive to the change in the clinical condition of the patient, as indicated by a favorable index of responsiveness. The results of the questionnaire were sensitive enough to demonstrate differences among treatment groups with relatively small sample sizes. This questionnaire has the characteristics of a useful instrument for assessment of outcomes, such as that after an operation.

Activities of Daily Living

Predicting postoperative pulmonary complications. Is it a real problem?

To identify predictors of postoperative pulmonary complications, a population of 278 patients, mainly hypertensive and diabetic patients undergoing elective general surgery was studied; 60% of the patients underwent abdominal surgery. Of the 278 patients, 6% had postoperative pulmonary complications: 3% had radiographic evidence of infiltrates or segmental atelectasis and 3% had clinical evidence of atelectasis. Among the two thirds of patients undergoing abdominal surgery, only patients with underlying asthma or chronic bronchitis were at increased risk. Generally, patients with better exercise tolerance by self-report, walking distance, or cardiovascular classification had lower rates. Pulmonary function tests did not help to delineate patients at higher risk of postoperative pulmonary complications. Simple clinical information provided as much data about the patients' risk as pulmonary function tests. Many of these complications occurred in patients who sustained other types of postoperative morbidity, suggesting that predicting and preventing postoperative cardiac morbidity may be the best approach to reducing postoperative pulmonary morbidity.

Aged

Relating patient characteristics at the time of admission to outcomes of hospitalization.

In clinical practice, physicians informally address patient characteristics such as illness severity, comorbidity, functional status and stability when considering prognosis and diagnostic or therapeutic interventions. These same attributes, more formally measured, have been used as measures of casemix in clinical research to classify patients into similar risk strata. To determine whether physician estimates of illness severity, function status and stability were predictive of morbidity, mortality, length of stay and average daily ancillary charges, a cohort of 604 patients was studied. The predictive ability of the patient characteristics were found to be outcome specific. Illness severity was a significant predictor of in-hospital morbidity and mortality, length of stay and charges (p less than 0.001). Functional status was predictive of in-hospital morbidity and mortality, 1 year mortality, length of stay and charges (p less than 0.01). Physician estimates of stability were predictive only of morbidity (p less than 0.01) and comorbidity was only a preditor of 1 year mortality (p less than 0.001). Stratifying patients on the basis of specific clinical characteristics determined at the time of admission will be useful in studies of patient outcomes and resource utilization.

Aged

Risk for postoperative congestive heart failure.

To identify predictors of postoperative congestive heart failure (CHF), a high-risk population, mainly hypertensive and diabetic patients undergoing elective general operations, was studied. Of the 254 patients, 6 per cent had postoperative CHF. Among patients with preoperative cardiac disease (that is, previous myocardial infarction, valvular disease or CHF), 17 per cent had postoperative CHF; in contrast with less than 1 per cent of those without cardiac disease (p less than 0.001). Patients with diabetes were also at high risk (12 versus 2 per cent, p less than 0.005), particularly those with cardiac disease. Patients who had equal to or greater than 40 millimeters of mercury increases or decreases intraoperatively in mean arterial pressure in relation to preoperative baseline had increased postoperative failure rates (p less than 0.02). Of note, postoperative failure rates were highest among patients with less than 500 milliliters per hour of net intake (input and output) (p less than 0.03). Risk for postoperative CHF was restricted to patients with preoperative symptomatic cardiac disease and was especially high if patients also had diabetes. Intraoperative fluctuations in mean arterial pressure increased the probability of postoperative failure, while the intraoperative administration of higher net volumes of fluid was associated with decreased risk.

Aged

Preoperative characteristics predicting intraoperative hypotension and hypertension among hypertensives and diabetics undergoing noncardiac surgery.

We prospectively studied patients with hypertension and diabetes undergoing elective noncardiac surgery with general anesthesia to test the hypothesis that patients at high risk for prognostically significant intraoperative hemodynamic instability could be identified by their preoperative characteristics. Specifically we hypothesized that patients with a low functional capacity, decreased plasma volume, or significant cardiac comorbidity would be at high risk for intraoperative hypotension and those with a history of severe hypertension would be at risk for intraoperative hypertension. Patients who had a preoperative mean arterial pressure (MAP) greater than or equal to 110, a walking distance of less than 400 m, or a plasma volume less than 3000 cc were at increased risk of intraoperative hypotension (i.e., more than 1 hour of greater than or equal to 20 mmHg decreases in the MAP). Hypotension was also more common among patients having intra-abdominal or vascular surgery, and among those who had operations longer than 2 hours. Patients older than 70 years or with a decreased plasma volume were at increased risk of having more than 15 minutes of intraoperative elevations of greater than or equal to 20 mmHg over the preoperative MAP in combination with intraoperative hypotension; this was also more common when surgery lasted more than 2 hours. Patients who had intraoperative hypotension tended to have an immediate decrease in MAP at the onset of anesthesia and were often purposefully maintained at MAPs less than their usual level during surgery with fentanyl and neuromuscular blocking agents. Patients who had intraoperative hyper/hypotension tended to have repeated elevations in MAP above their preoperative levels during the course of surgery, and such elevations precipitated interventions with neuromuscular blocking agents and/or fentanyl. Neither pattern was more common among patients who developed net intraoperative negative fluid balances. Both hypotension and hyper/hypotension were associated with increased renal and cardiac complications after operation. Patients with cardiac disease, especially diabetics, and those with negative fluid balances also had increased complications. Preoperative characteristics influence the susceptibility to intraoperative hypotension and hypertension, which are related to postoperative complications.

Aged

Intraoperative blood pressure. What patterns identify patients at risk for postoperative complications?

While monitoring blood pressure is a routine part of intraoperative management, several methods have been proposed to characterize intraoperative hemodynamic patterns as predictors of postoperative complications. In this prospective study of a high-risk population of hypertensive and diabetic patients undergoing elective noncardiac surgery, one objective was to compare different approaches to the assessment of intraoperative hemodynamic patterns to identify those patterns most likely to be associated with postoperative complications. Twenty-one per cent of the 254 patients sustained cardiac or renal complications after operation. Patients with more than 1 hour of greater than or equal to 20-mmHg decreases in mean arterial pressure (MAP) or patients with less than 1 hour of greater than or equal to 20-mmHg decreases and more than 15 minutes of greater than or equal to 20-mmHg increases were at highest risk for postoperative complications. Together these two patterns had a 46% sensitivity rate and a 70% specificity rate in predicting postoperative complications. Using 20% change in intraoperative MAP produced results nearly identical to 20-mmHg changes. When the duration of 20-mmHg changes was accounted for, changes of a greater magnitude (e.g., 40 mmHg) were not significant independent predictors of complications. The use of the mean difference from preoperative MAP was misleading because patients who experienced both high and low MAPs tended to have nearly normal mean MAPs, but high complication rates. The absolute magnitude of intraoperative MAPs, regardless of the preoperative levels, also was evaluated. The overall mean intraoperative MAP was not a significant predictor of complications. Specific intraoperative MAPs (e.g., less than 70 mmHg and more than 120 mmHg) also were evaluated. While neither was a significant predictor, there was a trend for increased complications among patients whose MAPs decreased to less than 70 mmHg. Intraoperative blood pressure should be analyzed in relation to the patient's preoperative blood pressure. Prolonged changes of more than 20 mmHg or 20% in relation to preoperative levels were significantly related to complications.

Blood Pressure

The post-operative electrocardiogram and creatine kinase: implications for diagnosis of myocardial infarction after non-cardiac surgery.

The objective of this study was to evaluate different approaches to the diagnosis of post-operative myocardial infarction. A total of 232 patients, mostly hypertensive and/or diabetic patients, who were undergoing elective non-cardiac surgery were evaluated pre-operatively. They were followed serially from the day of operation to discharge or the sixth post-operative day with daily clinical evaluations, electrocardiograms, creatine kinase and creatine kinase isoenzymes. In total 22% (51/232) of the patients had post-operative ECG changes in two or more leads. Only 1% developed new Q waves; most of the changes involved changes in the T or ST segments. Seventy percent of patients who had changes in their electrocardiogram were completely asymptomatic. The highest risk of ECG changes or symptoms occurred on the day of operation and the first post-operative day; evidence of post-operative infarction was infrequent after the second post-operative day. Creatine kinase levels rose an average of 250-300 IU on the first and second post-operative day (also the peak time for post-operative ECG changes), reducing its utility as an adjunct to the diagnosis of post-operative infarctions. Importantly, 52% (12/23) of the patients who had greater than or equal to 5% MB isoenzyme had neither ECG changes nor symptoms; the diagnosis of a myocardial infarction should not be made in these patients. In summary, most patients who experience ischemia or infarction post-operatively are asymptomatic. Symptoms should not be required for the diagnosis of post-operative infarction. Seemingly minor differences in criteria can produce major discrepancies in post-operative myocardial infarction rates (from 1 to 9%). The development of a final set of criteria will require further study but the diagnosis of post-operative infarction should probably be based on ECG changes, their duration and consistency, and the association of a positive MB fraction.

Aged

Postoperative changes in serum creatinine. When do they occur and how much is important?

The objective of this study was to evaluate the use of the serum creatinine in following postoperative renal function. In this prospective study of 278 patients (mainly hypertensives and diabetics) undergoing noncardiac surgery, the serum creatinines were followed from the first through the sixth postoperative day. Creatinine clearances were evaluated before operation and on the fourth to fifth postoperative day. During the first six days after the operation, 23% (65 of 278 patients) had an increase of serum creatinine greater than or equal to 20%. Such increases were sustained for greater than or equal to 48 hours in 12% of the patients (32 of 278), and half of these patients had not returned to their initial level of renal function by the time of discharge. Patients who sustained such a deterioration were at risk for nonoliguric renal failure if they had a subsequent insult (i.e., hypotension, reoperation, angiography, aminoglycosides). Such increases occurred early in the postoperative period--on the first or second postoperative day. As judged by the creatinine clearances, postoperative increases of greater than or equal to 20% in the serum creatinine identified most patients whose clearance fell more than 50%, although the serum creatinine did not accurately reflect changes in creatinine clearance among those patients who had undergone an amputation. It is concluded that the serum creatinine is useful in monitoring postoperative renal function. Of those patients who had postoperative increases in serum creatinine sustained for greater than or equal to 48 hours, as many as one third had evidence of impairment in renal function at the time of discharge.

Acute Kidney Injury

The preoperative and intraoperative hemodynamic predictors of postoperative myocardial infarction or ischemia in patients undergoing noncardiac surgery.

Among hypertensive and diabetic patients undergoing elective noncardiac surgery, preoperative status and intraoperative changes in mean arterial pressure (MAP) were evaluated as predictors of postoperative ischemic complications. Of 254 patients evaluated before operation and monitored during operation, 30 (12%) had postoperative cardiac death, ischemia, or infarction. Twenty-four per cent of patients with a previous myocardial infarction or cardiomegaly had an ischemic postoperative cardiac complication. Only 7% of those without either of these conditions sustained an ischemic complication. No other preoperative characteristics, including the presence of angina, predicted ischemic cardiac risk. Nineteen per cent of patients who had 20 mm Hg or more intraoperative decreases in MAP lasting 60 minutes or more had ischemic cardiac complications. Patients who had more than 20 mm Hg decreases in MAP lasting 5 to 59 minutes and more than 20 mm Hg increases lasting 15 minutes or more also had increased complications (p less than 0.03). Changes in pulse were not independent predictors of complications and the use of the rate-pressure product did not improve prediction based on MAP alone. In conclusion patients with a previous infarction or radiographic cardiomegaly are at high risk for postoperative ischemic complications. Prolonged intraoperative increases or decreases of 20 mm or more in MAP also resulted in a significant increase in these potentially life-threatening surgical complications.

Adult

Postoperative renal dysfunction can be predicted.

The two prior hypotheses of the study were that, among a high risk population of patients who were hypertensive, who had diabetes and who underwent elective general surgical treatment, the duration of intraoperative hypotension and hypertension (greater than 20 millimeters of mercury above or below the preoperative base line) and intraoperative administration of less than 300 milliliters per hour of saline solution containing fluids would identify patients at higher risk for postoperative renal dysfunction. Among those who had an intraoperative mean arterial pressure (MAP) that fell more than 20 millimeters of mercury below the base line, 15 per cent of those with fall of MAP lasting for greater than or equal to 60 minutes had postoperative renal dysfunction, whereas those with drops in pressure lasting for less than 60 minutes did not sustain increased postoperative renal dysfunction. Patients who had intraoperative MAP rise to greater than 20 millimeters of mercury above the preoperative base line value for greater than 30 minutes also had twice the rate of postoperative renal dysfunction. Fifteen per cent of the patients who received less than 300 milliliters per hour of isotonic saline-like fluids had postoperative renal dysfunction, significantly more than the 8 per cent of those who received greater than or equal to 300 milliliters per hour. Two intraoperative events also significantly increased postoperative renal dysfunction rates: cardiac arrest and the drainage of massive ascites. Patients with decompensated congestive heart failure at admission to the hospital had significantly increased postoperative renal dysfunction; these patients and probably should not undergo an operation unless it is an emergency. All of the patients, regardless of the magnitude of the operation and of its projected length or type of anesthesia, should be given greater than 300 milliliters per hour of isotonic saline-like solutions.

Aged

The therapeutic efficacy of critical care units. Identifying subgroups of patients who benefit.

The majority of patients are admitted to critical care units for observation and to facilitate intervention if deterioration occurs or complications develop. We attempted to determine if a reduction in mortality in a subgroup of these patients admitted directly to the critical care units could be identified. A new method using the scientific principles of a randomized trial applied to the case-control design was employed. All 1905 patients admitted to the medical service over a three-month period were prospectively evaluated for illness severity and stability. Patients who would not have been eligible for a randomized clinical trial were excluded. Based on the prospective evaluations, four prognostically distinct subgroups of patients were formed. An odds ratio for each of the prognostic groups was calculated, a ratio of greater than 1 indicating a protective effect of direct critical care admission. Only one subgroup of patients, the unstable moderately ill, had an odds ratio greater than 1 (13.3). These results, in association with the results of our previous study, suggest that at the time of admission to the hospital, direct admission to the critical care unit reduced mortality among the unstable moderately ill subgroup of patients.

Epidemiologic Methods