Subcutaneous epinephrine in the prehospital setting.

OBJECTIVES: To outline current practice regarding the prehospital use of subcutaneous epinephrine, and systematically review the existing literature to determine the level of support for its use in the elderly. Many health care personnel are reluctant to administer subcutaneous epinephrine for potentially life-threatening conditions such as asthma and anaphylaxis in older patients. This sytematic review examined the following focused question: "For older patients not known to have coronary artery disease, does administration of subcutaneous epinephrine carry a significant enough risk of cardiovascular side effects to mandate age as a relative contraindication to self-administration or emergency medical services administration in the prehospital setting?" METHODS: The MEDLINE and Health Star databases were searched to identify studies evaluating the use of subcutaneous epinephrine in the treatment of asthma and anaphylaxis. Bibliographies from included studies, known reviews, and textbooks were examined to identify additional studies. The strength of evidence presented in each study was assessed in accordance with the classification system proposed by the American Heart Association's Emergency Cardiovascular Care Committee. RESULTS: The review of the literature revealed only three case reports (level VII evidence) that record adverse reactions of epinephrine when used for anaphylaxis and allergy, while several level III and V studies found no adverse effects when used for asthma. No controlled trials documenting adverse effects were found. CONCLUSIONS: The authors did not find significant evidence to contraindicate the use of subcutaneous epinephrine in older patients who are not known to have coronary artery disease, who present with either asthma or allergic reactions.

Preoperative work up: are the requirements different in a developing country?

In developing countries there is a tendency to advocate routine testing in asymptomatic healthy patients to identify undocumented significant medical conditions. A retrospective review of pre- operative laboratory investigations undertaken in patients attending the General Surgical department was performed. Three hundred and twenty patients case notes were reviewed, patients were selected on the basis of common general surgical procedures. Two hundred and sixteen patients (67.5%) did not have any associated medical illness on history and physical examination. Analysis of laboratory results showed that 42/216 (19.4%) had low hemoglobin. An abnormal chest X-ray was the next common abnormality 11/103 (10.6%). Mild hypokalemia (> 3 mEq/L) was seen in 6/123 (4.8%) and a raised blood sugar level was seen in 1/113 (0.88%) patients. Only one patient with hemoglobin of 4.8 gm/dL needed preoperative intervention, the rest of the abnormalities did not effect the treatment plan or outcome. The results were in general agreement with other studies except for the high proportion of low hemoglobin seen in the female population. It is suggested that a thorough history and physical examination is a reliable and inexpensive preoperative screening tool. Guidelines for pre-operative investigations in American Society of Anesthesiologists Grade I (ASA I) patients are suggested.

The antiplatelet aggregatory activity of Acacia nilotica is due to blockade of calcium influx through membrane calcium channels.

1. The extract of Acacia nilotica (A. nilotica) blocked platelet aggregation mediated by platelet agonists, arachidonic acid (0.75 mM), ADP (4.3 microM), platelet activating factor (800 nM) and collagen (638 nM) in a dose-dependent manner. 2. The extract (0.21-1.4 mg/ml) blocked the platelet aggregation induced by Ca2+ ionophore, A-23187 (6 microM), in a dose-dependent manner, indicating that the Ca2+ influx is involved in aggregation. 3. The plant extract also inhibited aggregation in platelets pretreated with phorbol, 12-myristate, 13-acetate (196 nM) alone or in combination with ADP (4.3 microM), indicating an effect on protein kinase C. 4. These results indicate that the antiplatelet aggregatory activity of the extract of A. nilotica is mainly due to blockade of Ca2+ channels, although evidence also suggests the involvement of protein kinase C.