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Biomedical subjects

R F Armstrong

Publications and source records attributed to R F Armstrong.

36 records · Page 2Linked to original sources
PubMed1988

Primary rhabdomyosarcoma of the kidney. A light microscopic, immunohistochemical, and electron microscopic study.

Primary rhabdomyosarcoma of the kidney is a rare and highly aggressive tumor in the adult population. A case is reported in a 70-year-old woman with the diagnosis confirmed by immunohistochemistry and electron microscopy. This is the first case studied using the immunoperoxidase technique and the second with electron microscopic examination. To make a diagnosis of primary sarcoma, of the kidney, three criteria must be met: (1) a metastatic sarcoma must be ruled out; (2) the tumor must arise from renal parenchyma; and (3) a sarcomatoid variant of renal cell carcinoma needs to be excluded. The literature is reviewed and available clinical and pathologic details are summarized.

Aged↗
PubMed1988

Fibrous hamartoma of infancy.

Fibrous hamartoma of infancy is an uncommon, benign, subcutaneous fibrous proliferation, usually found during the first 2 years of life. It predominantly affects healthy boys and can be found in almost any subcutaneous tissue. This tumor can cause much concern about malignancy because it is firm and may be fixed to underlying tissues. Despite the occasional local recurrence, the clinical course is benign and the prognosis is excellent. Treatment is by local excision. The diagnosis is made easily by the characteristic histologic features. In order to avoid the misdiagnosis of malignancy and unnecessary radical therapy, both surgeon and pathologist must be familiar with this entity. We have reviewed six cases of fibrous hamartoma of infancy seen over a 5-year period.

Child, Preschool↗
PubMed1983

A system for the continuous measurement of oxygen uptake and carbon dioxide output in artificially ventilated patients.

A continuous, non-invasive system is described for measuring oxygen uptake (VO2) and carbon dioxide output (VCO2) in mechanically ventilated patients. Inspiratory and mixed expiratory gas samples were pumped through fine-bore tubing to a remote mass spectrometer for analysis. The expiratory flow transducer of a Siemens Servo 900B ventilator was used for expiratory flow measurement and inspiratory flow was calculated from this using the Haldane transformation. A desk-top computer calculated VO2, VCO2 and respiratory quotient. The system has been validated against standard methods of gas analysis and flow measurement (VO2 mean difference -10 ml min-1: SD 9.13; VCO2 mean difference 8.12 ml min-1: SD 4.66). Comparison with Douglas bag measurements in patients has been made (VO2 mean difference 10.7 ml min-1: SD 9.8; VCO2 mean difference -1.07 ml min-1: SD 4.7).

Carbon Dioxide↗
PubMed1983

The use of computerized learning in intensive care: an evaluation of a new teaching program.

A computer-assisted learning program in respiratory intensive care was introduced into the undergraduate curriculum at University College Hospital. Educational effectiveness was assessed. This method of learning was found to be highly acceptable to students. The improvement in students knowledge of the subject was up to three times greater in those who used the computer program, than a control group of students who received only teaching by conventional means, (P = 0 X 016). The results of a questionnaire designed to elicit students' attitudes to this learning experience are discussed.

Anesthesiology↗
PubMed1983

Intrauterine intussusception: case report and literature review.

Intussusception in the newborn is a unique clinical entity, and one of the most unusual causes of intestinal obstruction in infants. Its cause can be idiopathic, secondary to a local lesion or a complication of disease. Early diagnosis and treatment are important, because survival depends on them. The authors report a case of jejunal atresia secondary to intrauterine intussusception, followed by a literature review. Less than 30 cases have been adequately documented in the world literature. Eight reports from the literature are selected to highlight clues for early diagnosis, such as vomiting, with or without bile, abdominal distension and bloody stools, because of their prognostic implications. Intussusception is rare under the age of 3 months; the incidence is 0.3% in the neonatal period. Previous reports indicate that a confusing clinical picture has led to a delay in operation and a high mortality. The ultimate outcome depends on an acute awareness of the condition in the presence of the diagnostic clues in a newborn.

Female↗
PubMed1981

Continuous monitoring of right atrial oxygen tension in patients with myocardial infarction.

Right atrial oxygen tension (RAPvO2) was measured continuously in 26 patients admitted to a coronary care unit with acute myocardial infarction. A catheter incorporating a Clark type oxygen sensor at its tip was inserted percutaneously into the right atrium. Insertion was simple, safe and comparable to the introduction of a standard central venous pressure line. RAPvO2 correlated well with the patients' clinical condition and reflected both cardiac and pulmonary function. When breathing air 11 of the patients had sustained RAPvO2 levels of less than 34 mmHg (4.53 kPa). In this group there were eight deaths. Fifteen patients had an RAPvO2 greater than 34 mmHg (4.53 kPa) except for transient falls related to movement and in this group there were no deaths (p less than 0.002). The correction of arterial hypoxaemia by oxygen therapy raised RAPvO2 and lowered the heart rate. In some patients Dopamine and transvenous pacing raised RAPvO2 and could be adjusted with reference to the continuous recording. Movement often caused marked falls in RAPvO2 especially in the seriously ill. Evidence relating RAPvO2 to mixed venous oxygen and tissue oxygen is reviewed.

Adult↗
PubMed1981

Intravascular mixed venous oxygen tension monitoring. An analysis of electrode performance in 100 patients.

A lengthened umbilical artery catheter incorporating an oxygen electrode (Searle) was flow-guided to the pulmonary artery in 48 out of 62 attempts (77.4%). In the last 70 catheters used, electrode performance was evaluated over a total of 3687 h by comparison with an ABL2 (Radiometer) blood-gas analyser; 654 comparisons were made, of which 255 resulted in recalibration of the electrode output. When sampling intervals were within 6 h, in more than 80% of the comparisons the difference between in vivo and in vitro measurement was within +/- 0.4 kPa (+/- 3 mm Hg). Twenty-four electrodes were removed sooner than clinically indicated (mean useful life 48.5 h) because of failure of oxygen or pressure measurements.

Blood Gas Analysis↗
PubMed1978

Continuous monitoring of mixed venous oxygen tension (PvO2) in cardiorespiratory disorders.

The development of a miniature polarographic electrode mounted in the tip of a double-lumen plastic catheter has made possible continuous in-vivo monitoring of oxygen tension. Inexpensive catheters of this type have already proved of value as a means of continuously monitoring arterial oxygen tension in the newborn. In 25 patients with acute respiratory failure we found that these catheters could be safely and easily flow-guided into the pulmonary artery. In this way continuous recordings of mixed venous oxygen tension (PvO2) could be made for a period of several days. In our experience a sustained fall of PvO2 below 40 mm Hg proved to be a reliable indicator of respiratory or cardiac deterioration not always obvious by observation. In the patients described, falls of this order were seen after reductions in inspired oxygen concentration, in acute respiratory failure, in accidental underventilation, and in hypovolaemia and cardiac arrythmias. In some very ill patients routine nursing care involving movement of the patient caused pronounced falls of PvO2. Although electrode drift was an occasional problem, this could be checked by intermittent blood-sampling and recalibration if necessary.

Aged↗
PubMedDate not supplied

Long-term flow measurement: an assessment of the Siemens Servo 900B expiratory flowmeter.

The accuracy and linearity of three Siemens Servo 900B expiratory flowmeters have been assessed by comparison with a dry gas meter. Their performance was reassessed after 792,966 and 950 h respectively. The effects of changes in respiratory rate, relative humidity and oxygen concentration on the meters were studied. It was found that the meters were accurate and linear and that reliable measurements could still be made after long periods of continuous use. The meters were found to be less accurate at low respiratory rates. Relative humidity had little effect on flow measurement. Changes in oxygen concentration, and hence viscosity, led to errors of up to 16% in flow measurement.

Evaluation Studies as Topic↗