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Biomedical subjects

A H Morris

Publications and source records attributed to A H Morris.

At least 127 records · Page 7Linked to original sources
PubMed1977

Diffuse pulmonary disease after therapy with nitrogen mustard, vincristine, procarbazine, and prednisone.

Pulmonary reactions may follow therapy with nitrogen mustard, vincristine, procarbazine, and prednisone. Two patients with Hodgkin's disease are described who were treated with nitrogen mustard, vincristine, procarbazine, and prednisone and developed diffuse lung disease. Their disease processes were evaluated with serial pulmonary function studies, chest radiography, and open lung biopsy. Hypersensitivity reactions appeared to be responsible, and treatment with corticosteroids was successful. Procarbazine may have been the responsible agent.

Adult↗
PubMed1977

Oxygen therapy: appropriate use of nebulizers.

Control of the inspired O2 concentration requires both an appropriate O2 fraction from the nebulizer and an adequate flow of gas to the patient. We evaluated the O2 fraction and total flow of commercially available nebulizers operated under conditions commonly encountered in clinical use. Total gas flow O2 fraction, and back pressure were measured in 8 commercially available nebulizers. Measurements were made with no outlet tubing ,with 72 inches of dry corrugated plastic tubing, and with 72 inches of corrugated plastic tubing partially occluded with water. Nebulizers were studied individually ,and in parallel sets of 2 and 3, at both 40% and 70% O2 settings. Total flow was always lower and O2 fraction higher than that predicted by the manufacture under all experimental circumstances. As the outlet resistance of the nebulizers increased, the O2 fraction increased and the total flow decreased. The O2 fraction was, in addition, increased with the addition of each nebulizer in parallel. Currently available nebulizers have operating characteristics that do not permit the easy administration of accurate O2 therapy.

Aerosols↗
PubMed1975

A comparative study of atropine sulfate and isoproterenol hydrochloride in chronic bronchitis.

Fifteen subjects with chronic bronchitis were treated with inhaled atropine sulfate, isoproterenol hydrochloride, or placebo in a double blind crossover trial. Each drug was inhaled 4 times per day for 3 weeks. Baseline forced expiratory flows, specific airway conductance, airway resistnace, and functional residual capacity were measured weekly. These measurements were repeated 15 min and 60 min after laboratory inhalation of each agent, using a separate double blind protocol. No significant differences were observed among the mean baseline function studies during the 3 treatment periods. There were no significant differences in sputum production, sputum thickness, dyspnea, or mouth dryness among the 3 treatment periods. Side effects were mild; isoproterenol treatment was associated with an increased frequency of palpitations, and atropine treatment was associated with difficulty in voiding. Significant increases in lung function were apparent in the measurements made 15 min and 60 min after inhalation of atropine or isoproterenol. Mean values of flow and specific airway conductance increased, and mean values of airway resistance and functional residual capacity decreased after inhalation of either drug. There was no significant difference between the effects of atropine and isoproterenol on lung function, although both differed significantly from the effects of placebo (P less than 0.001). Inhaled atropine sulfate was as effective a bronchodilator as inhaled isoproterenol hydrochloride, and was well tolerated during the 3-week trial of daily therapy.

Adult↗
PubMedDate not supplied

Knowledge engineering using retrospective review of data: a useful technique or merely data dredging?

The process of extracting the knowledge or rules for medical decision making is not an easy task. One approach to knowledge engineering is to carefully review how decisions were made in the past with the goal of extracting the rules. The purpose of this project was to use previously collected data from ICU patients to derive the rules for the definition of hemodynamic stability. 97 ICU patients between 9/9/86 and 7/29/90 were included in the analysis. All of these patients had adult respiratory distress syndrome. Their mechanical ventilation was managed by a set of computerized protocols. We retrospectively searched the HELP system database for instructions that were not followed due to hemodynamic reasons. For each patient, we also chose one randomly selected therapy instruction which was followed to act as a control. For each instruction we then selected the corresponding hemodynamic data set. The data was then used in a stepwise logistic regression to determine the rules used for defining hemodynamic instability. We found that several of the hemodynamic parameters we had anticipated to be important were not even measured most of the time. The blood pressures and heart rate were almost identical between the hemodynamicly stable and unstable data sets. We conclude that the decision making process used by physicians has great variation, both between and within physicians. This makes knowledge engineering using retrospective techniques such as this prone to error and probably not very fruitful.

Bias↗
PubMedDate not supplied

A strategy for development of computerized critical care decision support systems.

It is not enough to merely manage medical information. It is difficult to justify the cost of hospital information systems (HIS) or intensive care unit (ICU) patient data management systems (PDMS) on this basis alone. The real benefit of an integrated HIS or PDMS is in decision support. Although there are a variety of HIS and ICU PDMS systems available there are few that provide ICU decision support. The HELP system at the LDS Hospital is an example of a HIS which provides decision support on many different levels. In the ICU there are decision support tools for antibiotic therapy, nutritional management, and management of mechanical ventilation. Computer protocols for the management of mechanical ventilation (respiratory evaluation, ventilation, oxygenation, weaning and extubation) in patients with adult respiratory distress syndrome ((ARDS) have already been developed and clinically validated at the LDS Hospital. These protocols utilize the bedside intensive care unit (ICU) computer terminal to prompt the clinical care team with therapeutic and diagnostic suggestions. The protocols (in paper flow diagram and computerized form) have been used for over 40,000 hours in more than 125 adult respiratory distress syndrome (ARDS) patients. The protocols controlled care for 94% of the time. The remainder of the time patient care was not protocol controlled was a result of the patient being in states not covered by current protocol logic (e.g. hemodynamic instability, or transport for X-Ray studies). 52 of these ARDS patients met extra corporal membrane oxygenation (ECMO) criteria. The survival of the ECMO criteria ARDS patients was 41%, four times that expected (9%) from historical data (p less than 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude of Health Personnel↗
PubMedDate not supplied

Performance of computerized protocols for the management of arterial oxygenation in an intensive care unit.

Computerized protocols were created to direct the management of arterial oxygenation in critically ill ICU patients and have now been applied routinely, 24 hours a day, in the care of 80 such patients. The protocols used routine clinical information to generate specific instructions for therapy. We evaluated 21,347 instructions by measuring how many were correct and how often they were followed by the clinical staff. Instructions were followed 63.9% of the time in the first 8 patients and 92.3% in the subsequent 72 patients. Instruction accuracy improved after the initial 8 patients, increasing from 71.5% of total instructions to 92.8%. Instruction inaccuracy was primarily caused by software errors and inaccurate and untimely entry of clinical data into the computer. Software errors decreased from 7.2% in the first 8 patients to 0.8% in subsequent patients, while data entry problems decreased from 7.5% to 4.2%. We also assessed compliance with the protocols in a subset of 12 patients (2637 instructions) as a function of 1) the mode of ventilatory support, 2) whether the instruction was to increase or decrease the intensity of therapy or to wait for an interval of time and 3) whether the instruction was 'correct' or 'incorrect'. The mode of ventilatory support did not affect compliance with protocol instructions. Instructions to wait were more likely to be followed than instructions to change therapy. Ninety-seven percent of the correct instructions were followed and 27% of the incorrect instructions were followed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Gas Analysis↗
PubMedDate not supplied

Computerized management of patient care in a complex, controlled clinical trial in the intensive care unit.

Acute respiratory distress syndrome (ARDS) is often not responsive to conventional supportive therapy and the mortality rate may exceed 90%. A new form of supportive care, extracorporeal carbon dioxide removal (ECCO2R), has shown a dramatic increase in survival (48%). A controlled clinical trial of the new ECCO2R therapy versus conventional continuous positive pressure ventilation (CPPV) is being initiated. Detailed care protocols have been developed by 'expert' critical care physicians for the management of patients. Using a blackboard control architecture, the protocols have been implemented on an existing hospital information system and will direct patient care and help manage the controlled clinical trial. Therapeutic instructions are automatically generated by the computer from data input by physicians, nurses, respiratory therapists, and the laboratory. Preliminary results show that the computerized protocol system can direct therapy for acutely ill patients.

Blood Gas Analysis↗
PubMedDate not supplied

Growth hormone stimulation testing with oral clonidine: 90 minutes is the preferred duration for the assessment of growth hormone reserve.

Provocative growth hormone (GH) testing using oral clonidine, a central alpha2-adrenergic agonist, is routinely performed by many pediatric endocrinologists worldwide. However, there is no clear consensus on the appropriate length of time over which serial blood samples for GH should be obtained for diagnosing GH deficiency. Retrospective analysis of data from oral clonidine GH stimulation testing performed at our center on 66 consecutive patients (42 males), aged 2 to 18 years, was performed to evaluate the clinical utility of obtaining GH samples at 0, 60, 90 and 120 min. In 29 of 30 patients, the presence of a normal GH response was demonstrated by the time of the 90 min sample. It is therefore concluded that serial GH sampling to 90 min is the preferred duration when screening for GH deficiency with clonidine.

Administration, Oral↗
PubMedDate not supplied

A modified single-breath DLCO apparatus.

A modified apparatus for measuring the single-breath carbon monoxide diffusing capacity of the lung (DLCO) is described. The modification permits simultaneous measurement of all lung volumes and capacities. In a comparison of conventional and modified devices, no significant differences for the measures of DLCO and total lung capacity were found.

Carbon Monoxide↗
PubMedDate not supplied

Modified ventilator with liquid-oxygen system for transport of adult patients with acute respiratory failure.

The value of modern techniques of respiratory care for patients with acute respiratory failure in specialized intensive care units has been documented. Unfortunately, many patients needing this type of care are located far from such resources and require transportation over large distances. This paper describes a modified bird Mark 14 ventilator and a Linde liquid oxygen attachment used successfully in the air and ground transport of 84 patients over a five-year period.

Adult↗
PubMedDate not supplied

Randomized clinical trials.

Explore the source record for details and available documents.

Extracorporeal Membrane Oxygenation↗
PubMedDate not supplied

Standardization of computation of single-breath transfer factor.

The transfer factor (TLCOsb) is currently widely used as a lung function test. Although the test maneuver itself is well described and uniformly approached by most workers, the computation technique varies considerably. Significant changes in the TLCOsb are induced by correcting for: blood hemoglobin concentration [Hb], apparatus and anatomic dead space (VD), alveolar gas sample dead space (VDbag), carboxyhemoglobin concentration (COHb), alveolar carbon dioxide fraction (FACO2), initial inspired gas (VI) conditions, and breath-hold time (t). The quantitative impact upon TLCOsb of the presence or absence of corrections was calculated using TLCOsb measurements from 245 normal subjects. The average change (%) in computed TLCOsb induced by correcting for the above variables is: Hb (+8%); VD (-8%); VDbag (-0.3 to -6%); COHb (+X% for X% COHb); FACO2 (+5%); VI (+4%); t (+7%). Since corrections are made by some laboratories and not by others and since no uniformity exists concerning the corrections to be made, it is possible for two laboratories to choose their computation routines in such a way that they would compute, from the same test results, TLCOsb values which differ by 41%. Standardization of the TLCOsb computation technique is needed.

Carboxyhemoglobin↗