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Biomedical subjects

R Davison

Publications and source records attributed to R Davison.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Adverse reactions to thrombolytic agents. Implications for coronary reperfusion following myocardial infarction.

The use of thrombolytic agents to dissolve coronary artery thrombi causing acute transmural myocardial infarctions has been shown to decrease short term mortality, and improve left ventricular function, in patients with acute transmural myocardial infarction. Several thrombolytic agents are currently available which differ mainly in cost, antigenicity, and mechanism of action. Current investigations are being directed at finding safer, more effective thrombolytic agents and at developing optimal therapy following thrombolysis. The complications of thrombolytic therapy are for the most part minor and reversible. Immediate and delayed hypersensitivity to streptokinase is rare. Hypotension and arrhythmias commonly accompany myocardial reperfusion and are usually benign and self-limited. Haemorrhagic complications are the most frequent and serious problems following the use of thrombolytic agents. They can be lessened by the proper selection of patients to avoid those at high risk of bleeding. The avoidance of unnecessary arterial and venous punctures will decrease the incidence of minor but annoying local bleeding. Those agents which are activated at the site of thrombi will hopefully cause fewer bleeding episodes, but early experience with these agents has not been able to demonstrate a lower rate. With careful attention to patient selection and follow-up, thrombolytic agents can be safely and effectively used in the management of patients with acute myocardial infarction.

Coronary Circulation↗
PubMedDate not supplied

Reassessment of the assumed A-V oxygen content difference in the shunt calculation.

A study was undertaken in 15 patients to compare measured and assumed arteriovenous oxygen (A-V O2) content differences and their effects on resultant shunt calculations. All patients were on volume ventilators and demonstrated a stable cardiovascular state. Simultaneous measurements of the O2 content of a pulmonary artery (PA) and of a superior vena cava (SVC) sample were compared. A mean A-V 02 content difference of 3.5 plus or minus 0.8 volumes percent was obtained from the PA and 2.6 plus or minus 1.1 volumes percent from the SVC. The resultant shunt calculations derived from measured A-V 02 content differences were compared with the calculation based on an assumed A-V O2 content difference of 5 volumes percent. A method for extrapolating a "true" A-V 02 content difference from an SVC blood sample was obtained. The extrapolated value resulted in a more representative "true shunt" calculation in 13 of the 15 patients.

Aged↗
PubMedDate not supplied

Using test dose challenges to restore essential therapy in patients with idiopathic anaphylaxis and pharmacophobia: report of a patient with idiopathic anaphylaxis and statin phobia.

Idiopathic anaphylaxis (IA) is a well-documented condition in which anaphylaxis occurs in the absence of an identifiable precipitant. However, many patients with IA find it difficult to accept this diagnosis and continue to search for an external cause. It is not uncommon for these highly anxious patients to discontinue essential medications that they feel are responsible for the reaction despite reassurance from their physicians to the contrary. In extreme cases, these patients may develop an actual phobia to preexisting medications and avoid them despite adverse consequences to their health. To illustrate this concept, we report a case involving a female patient with familial hypercholesterolemia who experienced a single episode of IA and developed a "statin phobia," falsely implicating her medication (lovastatin) for the reaction. After 5 years of failed therapy with other antihyperlipidemic agents, the patient finally agreed to undergo test dosing to a similar statin agent atorvastatin. On successful completion of the test, she resumed therapy with atorvastatin and her low-density lipoprotein (LDL) levels were reduced by 50% over 5 months. We conclude that patients with a confirmed diagnosis of IA who manifest phobic responses to beneficial medications should be reassured of the diagnosis promptly by their physician. When reassurance fails and the medication is essential to the patient's health, test dose challenges may be conducted to reintroduce the drug to the patient's regimen.

Anaphylaxis↗