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Biomedical subjects

P Armstrong

Publications and source records attributed to P Armstrong.

At least 109 records · Page 6Linked to original sources
PubMed1990

Alkalinisation of prilocaine for intravenous regional anaesthesia.

Ten volunteers underwent intravenous regional anaesthesia on two separate occasions using 40 ml prilocaine 0.5% to which was added 5 ml of either saline 0.9% or sodium bicarbonate 8.4%. Addition of sodium bicarbonate decreased the time of onset of loss of sharp touch and temperature sensations and of motor power. Time to full recovery of the arm was slower with the alkalinized solution and nine of the subjects preferred this block. The addition of sodium bicarbonate to prilocaine for intravenous regional anaesthesia may be clinically useful.

Adult↗
PubMed1990

Alkalinisation of prilocaine for intravenous regional anaesthesia. Suitability for clinical use.

Eighty unpremedicated patients undergoing day-case hand surgery under intravenous regional anaesthesia were randomly allocated to receive, in a double-blind study, either 40 ml 0.75% prilocaine hydrochloride, with 5 ml 8.4% sodium bicarbonate or 5 ml 0.9% saline. The alkalinised group had significantly less pain on injection (p = 0.0045), during surgery (p = 0.0074) and 5 minutes after the tourniquet was deflated (p = 0.0027). The time elapsed between insertion of the block and commencement of surgery was not affected.

Adolescent↗
PubMed1990

Post-traumatic fat embolism in the inferior vena cava.

Histologically, pulmonary fat embolism is seen in up to 97% of traumatized patients, yet almost all of them are asymptomatic. Although clinically significant, fat embolism syndrome is not common; it is a frequent cause of death when it does occur. The authors report the computed tomographic demonstration of fat embolism in the inferior vena cava of a patient who sustained multiple fractures. To their knowledge, no similar case has ever been described.

Adolescent↗
PubMed1989

Vascular smooth muscle responsiveness to noradrenaline and phenylephrine following experimental heart failure in dogs.

Adrenergic vascular responsiveness was assessed in the dorsal pedal artery and the saphenous vein in dogs before and after the development of congestive heart failure (CHF). Following development of severe CHF, both noradrenaline and phenylephrine could produce a greater maximum tension and a shift of the resultant concentration-effect curve to the left compared to the curves seen before the development of CHF. The saphenous vein was more sensitive than the dorsal pedal artery to both agonists before CHF. After CHF, the sensitivity difference to noradrenaline increased significantly but it remained unaltered to phenylephrine. Relative to noradrenaline, phenylephrine became more potent on the artery at peak CHF, whereas the potency ratio was unchanged in the saphenous vein at peak CHF. Prazosin was a competitive antagonist only against phenylephrine prior to CHF; competitive antagonism was not seen against noradrenaline or following CHF. Prazosin was less effective in antagonising noradrenaline induced contractions, as shown by an increase in IC50 values. These results are consistent with increased tissue sensitivity to adrenergic agents during CHF. The greater potency of phenylephrine in the artery at peak CHF suggests the presence of a greater proportion of alpha 1 adrenoceptors, which is consistent with the decrease in effectiveness of prazosin after the development of CHF.

Animals↗
PubMed1989

Full blood count values in adolescents.

This paper presents full blood count values for Irish adolescents. The range of results is presented and normal values are suggested. Of particular interest are the low MCV and MCH values among male adolescents. This would suggest that iron deficiency is more common in this group than was hitherto appreciated.

Adolescent↗
PubMed1988

Chest CT of unresectable lung cancer.

A major role of CT in lung cancer patients is to spare those with unresectable lesions unnecessary surgery. Here the CT findings of inoperable lesions (Stages IIIB and IV in the new International Staging System) are illustrated.

Aged↗
PubMed1988

Cost effectiveness of chest CT in T1N0M0 lung cancer.

The role of chest computed tomography (CT) in the evaluation of clinically staged T1N0M0 lung cancer is controversial. Using quantitative methods of decision analysis and data already available in the medical literature, the authors show how the clinical utility and cost effectiveness of chest CT are dependent on several variables: the prevalence of mediastinal metastases in T1N0M0 patients; the sensitivity and specificity of chest CT; patient life expectancy; and the morbidity, mortality, and monetary costs of CT, invasive mediastinal biopsy procedures, and curative surgical resection. When average values for these variables are used in the analysis, routine chest CT adds about 1 day to a T1N0M0 patient's life expectancy and saves about $150 per patient. Furthermore, a true-positive yield of 6% is sufficient for chest CT to be both clinically useful and cost saving, provided CT is readily available.

Cost-Benefit Analysis↗
PubMed1986

The clinical outcome of needle aspirations of the lung when cancer is not diagnosed.

One hundred thirty-two of 397 consecutive percutaneous fine needle aspirations done at the University of Virginia between January, 1979, and December, 1984, for pulmonary lesions showed no evidence of cancer on cytological examination. We reviewed the presenting symptoms, radiographic findings on the day of needle aspiration, and the descriptive cytological terms to determine if it was possible to distinguish benign from malignant disease in these 132 patients. We found a specific benign diagnosis in only 16 (12%) of the 132 patients, and 1 of them ultimately was found to have cancer. In the remaining 116 patients, analysis of age, sex, smoking history, presenting symptoms, radiographic findings at the time of needle aspiration, and cytological terms other than malignancy did not enable distinction of benign from malignant disease as the cause of the radiographic finding. In the group of 132 patients without suggestion of cancer on initial cytological study, 38 (29%) were subsequently found to have a malignant process.

Adolescent↗
PubMed1986

Communicating the significance of radiologic test results: the likelihood ratio.

The likelihood ratio is a useful but simple concept that helps the radiologist communicate to the clinician the significance of radiologic findings. It is defined as the ratio of the probabilities of a particular test result among patients with and without disease. Readily derivable from sensitivity and specificity, the likelihood ratio represents the degree to which a test result is positive or negative and serves as a proportionality constant that relates the pre- and posttest odds of disease in a linear manner. The linearity of the relationship permits the impact of a test result to be easily understood and allows for the integration of additional test results. The concept of likelihood ratio is explained in straightforward algebraic terms, and its practical application to clinical radiology is demonstrated by using several specific medical examples.

Adult↗
PubMed1986

Medical treatment of pregnancy hypertension.

Hypertension is the single commonest cause of maternal mortality, but prompt and effective treatment with a variety of drugs, some more familiar than others, can reduce the risk of both maternal and fetal death.

Adrenergic beta-Antagonists↗
PubMed1983

Computed tomographic features of round atelectasis.

Computed tomography (CT) of the chest is often variable in the evaluation of pulmonary masses. Our case demonstrated characteristic findings on CT that aided in the diagnosis of round atelectasis.

Diagnosis, Differential↗
PubMed1983

Giant-cell reparative granuloma of the hands and feet.

Giant-cell reparative granuloma occurring outside the jaw is unusual, being seen predominantly in the tubular bones of the hands and feet. It produces a lucent, expansile lesion in the metacarpals, metatarsals, or phalanges. The authors describe the radiographic and pathological features of 5 cases and review the literature.

Adolescent↗