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Biomedical subjects

R Bland

Publications and source records attributed to R Bland.

50 records · Page 3Linked to original sources

Use of physiologic monitoring to predict outcome and to assist in clinical decisions in critically ill postoperative patients.

A predictive index based on cardiorespiratory-monitored values of an earlier series of postoperative critically ill patients was tested in prospective clinical trials and found to be reasonably accurate, sensitive, and specific. The hypothesis was tested that the median values of patients who survived life-threatening postoperative conditions, rather than the norms of unstressed, healthy volunteer subjects, constitute a first approximation to the optimal therapeutic goals for critically ill postoperative patients. In a prospective series of 223 consecutive, critically ill postoperative patients, normal values were used as the therapeutic goals of the control patients, whereas the median values of surviving patients were used as the goals of therapy for the protocol group. The clinical conditions of the protocol group were at least as severe as those of the control group, but the mortality was significantly less in the protocol group (12.5 percent) than in the control group (35 percent); the number of life-threatening complications were also greater in the control group. These data suggest that at least half and possibly as much as two thirds of postoperative deaths may be due to physiologic problems that can be identified, described, predicted, and prevented. Therapy for the critically ill patient should be defined by physiologic criteria, and administration of therapy should be monitored to attain prophylactically optimal physiologic goals rather than giving therapy after a deficiency has occurred to attain normal values.

Clinical Trials as Topic↗

Clinical trial of an algorithm for outcome prediction in acute circulatory failure.

The authors evaluated prospectively an index for outcome prediction previously developed retrospectively from the cardiorespiratory data of a series of 113 critically ill postoperative general surgical patients. A predictive score generated by nonparametric multivariate analysis of the observed value for each cardiorespiratory variable and the frequency distributions of survivors' and nonsurvivors' values of that variable at each stage of postoperative shock. An overall global predictive index was then generated from the sum of the weighted predictive scores in each variable. This predictive index was tested prospectively in a new series of 156 operations and was found to be 94% accurate for the values of the last available data set, suggesting that the method satisfactorily predicts outcome. This index may be used as an objective measure of the severity of illness; i.e., it may be used to track the clinical course of postoperative general surgical patients during periods of critical illness. It was concluded that the predictive index aids in evaluation of monitored cardiorespiratory variables, improves interpretation of physiologic alternation, and facilitates clinical decision-making of critically ill patients at the bedside.

Adult↗

Comparison of the bioavailabilities and anticoagulant activities of two warfarin formulations.

Changes in the British Pharmacopoeia dissolution time requirements have necessitated reformulation of warfarin sodium ('Marevan'). The old and new formulations were compared with each other in eight healthy volunteers given a single 15 mg dose of each in a cross-over study and also in 19 patients receiving warfarin therapy. In the volunteer study, a significant but small increase in bioavailability was observed for the new formulation. However, the effects of the two formulations on the prothrombin ratio and on clotting factors II, VII, IX and X were not significantly different. Irrespective of formulation, the greatest changes in factors II, VII and X were observed after the first dose of warfarin. With factor IX, the greatest response was observed after the second dose. The clinical study in patients confirmed that the old and new formulations of Marevan are interchangeable on a dose for dose basis. A sensitive semi-automated warfarin assay technique is described.

Adolescent↗

Pathogenesis of respiratory failure (ARDS) after hemorrhage and trauma: I. Cardiorespiratory patterns preceding the development of ARDS.

To evaluate clinical and physiologic determinants of adult respiratory distress syndrome (ARDS), we studied 152 consecutively monitored patients with trauma and hemorrhage: 60 developed ARDS. The cardiorespiratory patterns of hemorrhage and trauma patients who did not develop ARDS were compared to those who subsequently did develop ARDS, but before the time of their ARDS. Comparisons also were made in the patients with trauma and those with hemorrhage, as well as in those who survived and those who did not. Hemorrhage and trauma patients who developed ARDS had greater reductions in blood volume, red cell mass, PaCO2 and O2 delivery throughout all stages, as well as greater pulmonary vascular resistance index (PVRI) and pH in the early and middle stages. Nonsurvivors of ARDS had greater deficits in blood volume and red cell mass, higher PVRI and pH, as well as lower central venous pressure (CVP), hemoglobin (Hgb), and PaCO2 than did ARDS survivors. Hemorrhage patients had lower blood volume, left ventricular function, O2 delivery and VO2, as well as higher systemic vascular resistance index (SVRI), PVRI, and O2 extraction than either the trauma patients or normal subjects. Description of the temporal cardiorespiratory patterns before the clinical appearance of ARDS showed the progressive appearance of these deficits beginning 36 h before the hypoxemia was observed. The data are consistent with the concept that ARDS after hemorrhage and trauma is preceded by hypovolemia, reduced myocardial performance, inadequate O2 delivery, and inadequate O2 extraction needed to maintain VO2 at the elevated levels demanded by the increased metabolic requirements of the injured patients. Thus, the so-called shock lung is a complication of shock associated with hypovolemia, hypoxemia, and inadequate cardiac compensatory responses to increasesd O2 demands.

Female↗

Cardiorespiratory monitoring in postoperative patients: I. Prediction of outcome and severity of illness.

An index for prediction of outcome for use as a measure of the severity of illness was developed by a nonparametric multivariate analysis of cardiorespiratory data from 113 critically ill postoperative general surgical patients. This severity (predictive) index was based on a computerized algorithm that compares a given observed value with the frequency distributions of survivors and nonsurvivors. The difference in the mean values of this index for survivors and nonsurvivors was statistically significant (p less than 0.001) during each stage of shock. Sensitivity of the index in prediction of survival ranged from 70-93% depending upon stage, the specificity of the index ranged from 76-92%, and the predictive accuracy ranged from 87-96%. The severity index is used as a process measure to track the course of critically ill patients and to evaluate the efficacy of alternative therapies.

Cardiovascular System↗

Manic depressive illness in adolescence and childhood: review and case report.

The literature on this topic from its inception by Kraepelin is reviewed. While Kraepelin and the French school always recognized juvenile mania, the Anglo-American school has no such unanimity of opinion. Less than 100 cases are described in the world literature. In Canada affective psychoses are rarely diagnosed under age 10 and of all affective psychoses admitted to institutions less than 5% are under age 20. The differences between child and adult mania are outlined. It is proposed that manic-depressive illness occurs in children but is not diagnosed more often because of its dissimilar presentation to the adult form and doubts about its existence in childhood. The case history of a 14 year old boy who presented in a hypomanic state is described. There was a strong family history of affective disorder. Both his parents and his half-sister were already on lithium for manic-depressive illness.

Adolescent↗

Cardiorespiratory monitoring in postoperative patients: II. Quantitative therapeutic indices as guides to therapy.

Immediate (proximate) and late (optimal) therapeutic goals for critically ill postoperative general surgical patients were based on the frequency distributions of cardiorespiratory data of the survivors immediately after resuscitation and in the late stage of shock, respectively. An algorithm was developed which expresses in quantitative terms the distance from observed values for each variable to both of these therapeutic goals. Further, composite indices were also made of related cardiorespiratory variables that reflect the important aspects of acute circulatory failure and its therapy; i.e., volume, flow, tissue perfusion, oxygen transport, and bodily response to stress. The therapeutic indices of nonsurvivors were found to have greater mean deficits that survivors (p less than 0.05) during all but the middle stage of shock. The therapeutic indices greatly aid in the organization and display of monitored cardiorespiratory variables by expressing the circulatory defects in easily understood indices that can be related to therapeutic interventions. Moreover, the interactions of the various aspects of cardiorespiratory function before and after therapy may be easily observed.

Cardiovascular System↗

Physiologic monitoring goals for the critically ill patient.

Definition of the appropriate therapeutic goals for physiologic monitoring of patients postoperatively was approached by analyzing more than 50,000 values of the 20 most commonly monitored variables in a series of 113 critically ill patients throughout their immediate postoperative course. In general, normal values were poor criteria for monitoring, since normal values were restored in an average of 75 per cent of the survivors and 76 per cent of the nonsurvivors for the five most frequently measured variables; that is, arterial pressure, heart rate, central venous pressure, wedge pressure and cardiac output. Moreover, an average of 56 per cent of the 20 most commonly monitored variables of nonsurvivors was restored to the normal range. Furthermore, 34 per cent of all the nonsurvivors' values were within the normal range; this was only 2.4 per cent less than the percentage of normal values for the survivors. The empirically determined median value of the survivors taken in the late stage during periods remote from therapy was found to be a better criterion for therapeutic goals for most variables, including blood flow, oxygen transport and most intravascular pressures. However, normal values were satisfactory for arterial pressure, peripheral resistance, pH, mixed venous oxygen tension and arterial carbon dioxide tension, largely because of the biphasic patterns of these variables.

Blood Chemical Analysis↗

Metabolism of labetalol by animals and man.

1 The disposition and metabolism of labetalol and either 14C- or 3H-labetalol has been studied in mouse, rat, rabbit, dog and man. 2 Radiolabelled labetalol was administered orally at doses of 100 mg/kg to the mouse, up to 50 mg/kg to the rat and rabbit, 20 mg/kg to the dog and 200 mg to man. From measurements of the total plasma radioactivity it was shown that labetalol was well absorbed by all the species. When the measurements of plasma radioactivity and labetalol concentrations were compared, it was found labetaol had been extensively metabolized by the first-pass effect in rat, rabbit and man. Metabolism by this route occurred to a lesser extent in the dog. 3 Radiochemical analysis of the tissues from rats, rabbits and dogs showed that the highest concentrations of radioactivity were found in the lung, liver and kidney. Very little radioactivity was present in the brain. Over 99% of the radioactivity was cleared from the tissues by 7 d. When doses of up to 200 mg 14C-labetalol/kg were given to pregnant rats and 50 mg 14C-labetalol/kg to pregnant rabbits, autoradiographic and radiochemical analysis of the full-term foetuses showed that only small amounts of radioactivity were present in the foetus. 4 The mouse excreted 72%, the rate 48%, the rabbit 61%, the dog 66% and man 60% of the oral dose of radioactivity in the urine. Analysis of themouse and rat faeces showed that the remainder of the dose of radioactivity was excreted in the faeces. 5 Radiochemical analysis of the urine and faeces collected from rats and dogs after an intravenous dose of 1 mg 14C- and 3H-labetalol/kg showed that excretion of radioactivity occurred via both the kidney and bile. 6 An intravenous dose of 1 mg 3H-labetalol/kg to dog and 1 mg 'cold' labetalol/kg to man was not as extensively metabolized as a similar oral dose. 7 The percentage of the dose excreted in the urine as unchanged drug was 2% in the rabbit, 11% in the rat, 19% in the dog and up to 5% in man. The O-phenyl glucuronide was the major metabolite present in the mouse, rat, and rabbit urine. Dog and man also formed this metabolite, but to a lesser extent. A second glucuronide was the major metabolite present in dog urine. This was probably formed through conjugation of glucuronic acid was the secondary alcohol group of labetalol. The major metabolite present in human urine was an unidentified conjugate of labetalol. Minor metabolites of labetalol present in rat, rabbit and dog urine were hydroxylabetalol and its glucuronyl conjugate.

Administration, Oral↗

Sex differences in rates of depression: cross-national perspectives.

Rates of depression are compared by sex in epidemiologic surveys conducted in the United States, Canada, Germany and New Zealand. These surveys used similar sampling and diagnostic techniques and the data were standardized to the age and sex distribution of the USA to facilitate comparisons. Data show that the rates of major depression and dysthymia are higher in females than in males and are approximately equal for bipolar disorder across all four countries. The mean age of onset of major depression did not differ by sex across the four countries. The rates of major depression for males seem to be rising and for females stabilizing for birth cohorts born after 1945 (World War II). New data from the National Comorbidity Survey which has younger birth cohorts can directly examine this issue.

Adult↗

A survey of aspirin use in the pre-hospital treatment of suspected acute cardiac chest pain.

Recent large studies have demonstrated the value of early intervention with aspirin and thrombolysis in myocardial infarction for patients reaching hospital alive. Management of patients with suspected myocardial infarction prior to hospitalisation is an important area of acute cardiac care. Guidelines for good practice suggest the early administration of aspirin should be considered when an infarct seems likely. We have found aspirin less commonly used than other interventions prior to hospital admission in patients with suspected acute cardiac pain.

Adult↗