照原文搬过来,怕翻译有误, 会逐渐翻译+summarize成华语
* Local treatment is discussed as follows:
o A negative-pressure extraction device (ie, the extractor) may be useful, although the benefit is unproven. The extractor creates a negative pressure of 1 atm. Apply it to the sting site after incision. Oral extraction is contraindicated.
o Use ice bags to reduce pain and to slow the absorption of venom via vasoconstriction. This is most effective during the first 2 hours following the sting.
o Immobilize the affected part in a functional position below the level of the heart to delay venom absorption.
o Calm the patient to lower the heart rate and blood pressure, thus limiting the spread of the venom.
o For medical delay secondary to remoteness, consider applying a lymphatic-venous compression wrap 1 inch proximal to the sting site to reduce superficial venous and lymphatic flow of the venom but not to stop the arterial flow. Only remove this wrap when the provider is ready to administer systemic support. The drawback of this wrap is that it may intensify the local effects of the venom.
o Apply a topical or local anesthetic agent to the wound to decrease paresthesia; this tends to be more effective than opiates.
o Administer local wound care and topical antibiotic to the wound.
o Administer tetanus prophylaxis.
o Administer systemic antibiotics if signs of secondary infection occur.
o Administer muscle relaxants for severe muscle spasms (ie, benzodiazepines.)
* Systemic treatment is instituted by directing supportive care toward the organ specifically affected by the venom.
o Establish airway, breathing, and circulation (ie, ABCs) to provide adequate airway, ventilation, and perfusion.
o Monitor vital signs (eg, pulse oximetry; heart rate, blood pressure, and respiratory rate monitor).
o Use invasive monitoring for patients who are unstable and hemodynamic.
o Administer oxygen.
o Administer intravenous fluids to help prevent hypovolemia from vomiting, diarrhea, sweating, hypersalivation, and insensible water loss from a tropical environment.
o Perform intubation and institute mechanical ventilation with end-tidal carbon dioxide monitoring for patients in respiratory distress.
o For hyperdynamic cardiovascular changes, administration of a combination of beta-blockers with sympathetic alpha-blockers is most effective in reversing this venom-induced effect. Avoid using beta-blockers alone because this leads to an unopposed alpha-adrenergic effect. Also, nitrates can be used for hypertension and myocardial ischemia.
o For hypodynamic cardiac changes, a titrated monitored fluid infusion with afterload reduction helps reduce mortality. A diuretic may be used for pulmonary edema in the absence of hypovolemia, but an afterload reducer, such as prazosin, nifedipine, nitroprusside, hydralazine, or angiotensin-converting enzyme inhibitors, is better. Inotropic medications, such as digitalis, have little effect, while dopamine aggravates the myocardial damage through catecholaminelike actions. Dobutamine seems to be a better choice for the inotropic effect. Finally, a pressor such as norepinephrine can be used as a last resort to correct hypotension refractory to fluid therapy.
o Administer atropine to counter venom-induced parasympathomimetic effects.
* Insulin administration in scorpion envenomation animal experiments has helped the vital organs to use metabolic substrates more efficiently, thus preventing venom-induced multiorgan failure, especially cardiopulmonary failure. Unfortunately, no human studies have been conducted.
* Administer barbiturates and/or a benzodiazepine continuous infusion for severe excessive motor activity.
* The use of steroids to decrease shock and edema is of unproven benefit.
* Antivenin is the treatment of choice after supportive care is established. The quantity to be used is determined by the clinical severity of patients and by their evolution over time. Unfortunately, predicting the evolution of symptoms and, thus, the amount of antivenin that is needed in the future, is difficult.
o The antivenin significantly decreases the level of circulating unbound venom within an hour. The persistence of symptoms after the administration of antivenin is due to the inability of the antivenin to neutralize scorpion toxins already bound to their target receptors.
o Time guidelines for the disappearance of symptoms after antivenin administration are as follows:
+ Centruroides antivenin: Severe neurologic symptoms reverse in 15-30 min. Mild-to-moderate neurologic symptoms reverse in 45-90 min.
+ Non-Centruroides antivenin: In the first hour, local pain abates. In 6-12 hours, agitation, sweating, and hyperglycemia abate. In 6-24 hours, cardiorespiratory symptoms abate.
o While an anaphylaxis reaction to the antivenin is possible, the patient is at lower risk for this than with other antivenins for other poisonous envenomations because of the huge release of catecholamines induced by the scorpion venom. However, the larger the dose of antivenin, the greater the chance for serum sickness.
* A vaccine preparation was tried in experimental animals but was not pursued because of the need to prepare different antigens according to different geographical areas and to different species of scorpions living in the same area.
* In some cases, be aware that meperidine and morphine may potentiate the venom. Also, the concurrent use of barbiturates and narcotics may add to the respiratory depression in patients who have been envenomated.
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发表于 22-6-2009 10:44 PM
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