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Biomedical subjects

R W Chang

Publications and source records attributed to R W Chang.

At least 73 records · Page 4Linked to original sources
PubMed1990

Therapeutic ultrasound in the treatment of musculoskeletal conditions.

This paper presents a quantitative synthesis of the literature addressing the effectiveness of ultrasound in selected musculoskeletal conditions. Pain and range of motion appear to improve following ultrasound treatment in acute periarticular inflammatory conditions and osteoarthritis, but not in chronic periarticular inflammatory conditions. Placebo response and experimenter expectancy bias can not be ruled out as explanations for the positive results. The literature concerning the therapeutic efficacy of ultrasound for pain and immobility in musculoskeletal conditions is therefore inconclusive. Well-designed clinical trials are needed to resolve this question.

Bone Diseases↗
PubMed1989

Individual outcome prediction models for intensive care units.

Prognostic criteria based on static analysis of group statistics do not help much in decisions to withhold or withdraw therapy from intensive care unit (ICU) patients too ill to benefit, since they do not provide adequate information on the features that distinguish non-survivors from survivors. A predictive model which uses dynamic analysis of severity scores based on physiological variables is presented here along with the results of tests of the model in 831 ICU patients. 109 patients were correctly predicted to die by the model. Of 722 whose prediction was outcome unknown, 181 died. Thus, the odds for prediction of death among non-survivors were 0.376. Since there were no false predictions of death, the estimated chance of a false prediction was 0.0055.

Bayes Theorem↗
PubMed1989

Prediction of outcome in patients with acute variceal haemorrhage.

Prediction of outcome in 87 patients following acute bleeding oesophageal and gastric varices due to portal hypertension from chronic liver disease was studied at our hospital over a 30-month period. The overall mortality rate was 26 per cent (23/87), with the operative mortality rate (50 per cent) being more than triple the non-operative mortality rate (14 per cent). The initial prothrombin time ratio (PTR) alone was significantly different in survivors and non-survivors both in the operated and non-operated patients. The only survivor in the whole material with a PTR greater than or equal to 2.2 was a patient who was transferred and underwent successful liver transplantation elsewhere. Among operated intensive care unit (ICU) patients, the Glasgow predictor gave a mean probability of discharge of 0.81 (s.d. 0.15) in 13 survivors and of 0.35 (s.d. 0.35) in the 15 non-survivors (P less than 0.001). In the 11 non-operative ICU patients, who had failed sclerotherapy, the Glasgow predictor could not be validated. Fourteen ICU deaths were associated with significant hypotension defined as a systolic blood pressure less than 90 mmHg for greater than 1 h.

Acute Disease↗
PubMed1989

An analysis of the utilisation of an intensive care unit.

We monitored the response to intensive care of 480 patients by calculating the difference in their organ failure score on the day of admission and that on the day of discharge, and related the response to hospital outcome. The patients were classified into: A) those who benefited (33%), B) those who might have benefited (28%), C) those who would never or would no longer have benefited (18%) and D) those who did not require intensive care management (21%). The criteria used were response to therapy, individually predicted outcome, hospital outcome and perceived need for intensive care. Group C patients used up 26.8% of the total intensive care unit bed days, while group D patients occupied 3.7%. We concluded that an acute terminal care unit to care for group C patients who have no hope of survival is more appropriate to the needs of our hospital than an intermediate care unit for overnight monitoring of uncomplicated postoperative and non-operative patients (group D).

Critical Care↗
PubMed1989

Low catheter sepsis rate in a hospital-wide nutrition support service.

Four hundred and seventy-nine catheters were inserted into 471 patients over a 6 year period for the administration of total parenteral nutrition. Catheter insertion was carried out only by surgical members of the nutrition support service. Complications were recorded prospectively and stored, with all other details of treatment, on a microcomputer. The mechanical complication rate was 6.4% of catheters used and the incidence of catheter related sepsis (CRS) 2.9%. Catheters which grew organisms, but were not associated with CRS, occurred in 3.7% of catheters used. Catheter care was performed by nurses throughout the hospital under the supervision of the nutrition nurse. The results of our work indicate that restriction of catheter care to specialised nurses is unnecessary providing there is staff education and support. In addition, the value of routine catheter tip culture in patients, not suspected of having infection, is questionable.

Journal Article↗
PubMed1989

Accuracy of decisions to withdraw therapy in critically ill patients: clinical judgment versus a computer model.

Two clinicians and the nursing sisters working in the ICU evaluated the chance of survival of ICU patients every day. Patients were assessed either as "outcome unknown or will die." These predictions were compared with those made by computerized trend analysis of daily acute physiology and chronic health evaluation (APACHE II) scores corrected for the presence and duration of major organ system failure. The predictions were not acted upon during the study. Comparing the predictions with actual hospital outcome, the doctors and nurses had a false-positive diagnosis rate for dying of between 7.7% and 16.7%, while there were no false predictions by the computer model. The patients predicted to die by the doctors and nurses were not completely identical to those predicted by the computer. Predictions of doctors and nurses that were confirmed by the computer had a sensitivity of 20% and no false predictions of death.

Decision Making, Computer-Assisted↗
PubMed1989

An applied anatomical study of the ostia venae hepaticae and the retrohepatic segment of the inferior vena cava.

In sixty normal adult livers the retrohepatic segment of the inferior vena cava was found mostly to assume a curve to the left (75.00%). This segment has a length of 7.1 cm and is totally encircled by liver substance in 6.67% of cases. Altogether 492 ostia venae hepaticae were studied, averaging 8.2 per liver and classified as large, medium and small. The large ostia are divided into superior (SLO) and inferior (ILO) openings. The SLO are found opening into the upper end of the hepatic segment of the inferior vena cava, frequently with part of the venous walls exposed outside the liver. The ILO and medium ostia are present in 95% of the livers, appearing mainly on the lower quarter of the right half of the wall of the retrohepatic segment of the inferior vena cava as well as on the left anterior wall of that segment. The ILO may serve as the exit for several hepatic veins and they may be multiple. Their significance in respect of liver surgery is discussed.

Autopsy↗
PubMed1988

The diagnosis of polyarteritis nodosa. II. Empirical verification of a decision analysis model.

We evaluated our literature-based estimates of diagnostic test characteristics and aggressive and conservative strategies for the diagnosis of polyarteritis nodosa (PAN) by reviewing 1980 through 1985 data from the University of Chicago Medical Center, Michael Reese Hospital, and Northwestern University Medical School. Test specificity was calculated by reviewing pathology and radiology reports on all relevant procedures done at the University of Chicago Medical Center in 1984 and 1985. There were no reports of false-positive findings (including angiography); thus, test specificity was 100% for muscle, nerve, kidney, liver, and testicular biopsy, which was comparable with our literature-based estimate of 97%. Test sensitivity was based on the 18 confirmed cases of PAN from the 3 institutions and was similar to that in published reports, ranging from 0% for liver biopsy to 100% for visceral angiography. Review of each case for diagnostic test sequence showed an average of 2 diagnostic procedures to confirm the diagnosis (range 1-6). Eight of 18 patients were evaluated according to the conservative strategy we proposed from our literature-based decision analysis approach. No patient was evaluated with the aggressive strategy, although 1 patient had 6 invasive procedures. Of the remaining 10 patients, 9 represented cases that might have been confirmed had the conservative approach been used, and if it had been used, 6 patients would have had the diagnosis confirmed. Thus, the minimum sensitivity of our conservative strategy is 78%, although based on these data, it could be as high as 100%.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1988

Predicting outcome among intensive care unit patients using computerised trend analysis of daily Apache II scores corrected for organ system failure.

Daily Apache II scores were determined prospectively on 310 consecutive adult Intensive Care Unit (ICU) patients to reflect the dynamic pathophysiological processes affecting ICU patients. Organ failure scores were derived from the Apache II scores by applying a coefficient which corresponded to the number and duration of organ failures to account for the increased mortality associated with established major organ-system failures. Computerised trend analysis of data from the first 100 patients was used to develop criteria for predicting hospital outcome of the ICU patients. The analysis took into account the absolute value of the daily scores and the rate of change relative to that of the previous day. Allowance was made for changes in scores as a result of surgery or major iatrogenic complications arising after admission to the ICU. The criteria were then tested prospectively on the next 210 consecutive ICU patients. Predictions by Apache II assessments were NOT used to influence clinical decisions during the study period. It was possible to predict with a specificity of 100% 37 out of the 72 deaths in the test group. The predictive power of daily organ failure scores was superior to those obtained from a single Apache II assessment or from daily Apache II scores by a factor of 5.3 and 1.4 respectively. The estimated long-term risk of a false prediction is 1.4% at the 95% confidence level.

Critical Care↗
PubMed1988

Audit of intensive care: a 30 month experience using the Apache II severity of disease classification system.

608 patients admitted to a general Intensive Care Unit (ICU) over a 30 month period were analyzed according to the Apache II Severity of Disease Classification System on day one of admission. Hospital outcome details were available on 583 patients in the series. The mean Apache II scores for survivors (396) and non-survivors (187) were 13 (SD 7) and 24 (SD 9), and their Risk of Death were 16 (SD 16) and 47 (SD 27) respectively (p less than 0.001 for both). The majority of deaths (75%: 141/187) in our series came from those with chronic ill health (55%: 103/187), of whom 37% (38/103) were in endstage disease, and those with "old" trauma (18%: 34/187) often with incipient sepsis transferred from other hospitals after a mean delay of 9 days. Our higher than predicted mortality (mortality ratio 1.2) in comparison with centres in the United States of America (US) may be partly explained by the high proportion of our population from these unfavourable groups, by our use of the best Glasgow Coma Scale in the first 24 h following admission, and the major differences between our patient population and that of the US upon which the Apache II was based. The presence of these large unfavourable groups indicates a change in our admission policy is warranted.

Adult↗
PubMed1988

Predicting deaths among intensive care unit patients.

Daily APACHE II assessments to reflect the dynamic pathophysiologic processes affecting ICU patients were carried out prospectively on 212 adult ICU admissions for the purpose of predicting hospital outcome. Trend analysis of daily APACHE II scores was used to develop the first set of criteria for predicting deaths among the ICU patients. The analysis took into account the absolute value of APACHE II score of each day and the rate of change relative to that of the previous day. One hundred consecutive adult ICU admissions were used to determine the criteria that were tested on the following 112 consecutive adult ICU admissions. Daily APACHE II scores identified correctly 16 of the 34 patients who died. A second set of criteria was next derived by raising the values of the original limits in order to build-in greater margins of safety without too great a loss of sensitivity. The predictive power of daily APACHE II scores using the second set of criteria was superior to that of a single APACHE II score by a factor of 4. Predictions were not used to influence clinical decision-making during this study.

Aged↗
PubMed1988

Diagnostic value of the history and examination in giant cell arteritis: a clinical pathological study of 81 temporal artery biopsies.

To determine the value of the history and examination in predicting a temporal artery biopsy result, 81 temporal artery biopsies between 1974-1980 were studied. Each biopsy was scored blindly and independently by 2 pathologists and correlated with clinical data and the indications for biopsy at the time of the biopsy. Thirteen biopsies had giant cells and were considered positive, 8 had mononuclear inflammatory cells in the wall (7 cases) or healed arteritis (1 case) and were considered probable, and 60 were negative. In patients with an elevated sedimentation rate, the presence of a sign (tenderness or abnormal temporal artery), or a symptom (visual change or headache) predicted 18 of 21 (86%) positive-probable biopsies, but misclassified 32 of 60 negative biopsies. Attempts to derive a clinical decision rule with improved specificity resulted in unacceptably low sensitivity (missing 5 of 21 positive-probable biopsies). A minimum 5-year followup showed that those patients treated with steroids had a 6-fold increase in fractures and a 4-fold increase in cataracts.

Aged↗
PubMed1987

Long-term treatment of rheumatoid arthritis comparing nabumetone with aspirin.

This report summarizes the results of a 17-investigator multicenter six-month randomized double-blind parallel group study. The safety and efficacy of nabumetone 1,000 mg taken at bedtime was compared with that of aspirin 900 mg four times daily in the treatment of adult patients with active class II or III classical or definite rheumatoid arthritis. Two hundred sixty-four patients were entered into the study. Two hundred fifty-seven (126 nabumetone and 131 aspirin) patients were evaluable for safety. Two hundred thirty-four (113 nabumetone and 121 aspirin) patients were evaluable for efficacy. There was significant improvement in each of six clinical measurements of efficacy in both treatment groups and little difference between groups. The somewhat greater improvement in articular index and duration of morning stiffness in the nabumetone-treated group did not reach statistical significance. There was an equal percentage of patient withdrawal for lack of efficacy in each group. Overall, the rate of patient withdrawal due to adverse experiences was greater (p = 0.01) for aspirin-treated patients. These experiences were usually dispepsia, abdominal pain, and tinnitus. It was concluded that nabumetone was an effective anti-inflammatory drug in the treatment of rheumatoid arthritis with less toxicity than aspirin.

Adolescent↗
PubMed1987

Comparison of the safety and efficacy of nabumetone and aspirin in the treatment of osteoarthritis in adults.

A six-month, multicenter, double-blind study compared the efficacy and safety of two therapeutic regimens in 332 patients with osteoarthritis. The patients received either 1,000 mg of nabumetone as a single bedtime dose or 900 mg of aspirin in four divided doses. At the end of the study, patients in both treatment groups showed significant improvement from baseline for all five parameters; no statistically or clinically significant differences were observed between the groups. The safety data did reveal clinically and statistically significant differences between the groups. Aspirin-treated patients experienced a greater frequency of withdrawal from the study because of adverse experiences (34 percent versus 13 percent), a greater incidence of having at least one treatment-related adverse experience (73 percent versus 52 percent), a greater percentage of patients with at least one moderate or severe treatment-related adverse experience (47 percent versus 22 percent), and a greater percentage of patients with treatment-related adverse experiences affecting the gastrointestinal system (43 percent versus 32 percent) or the inner ear (32 percent versus 10 percent). The results of this study demonstrated that nabumetone, 1,000 mg at bedtime, is as efficacious as aspirin, 900 mg four times daily, produces fewer adverse effects, and is indicated in the treatment of osteoarthritis.

Adult↗