By X. Finley. Culver-Stockton College. 2018.
Vigilant and scheduled replacement of intravascular devices presumably minimizes the incidence of catheter-related sepsis discount 100 mg lasix visa. The first can be done over a wire using sterile Seldinger technique cheap lasix 100 mg without a prescription, but the second change requires a new site generic lasix 40 mg with mastercard. Whenever possible discount lasix 40 mg visa, peripheral veins should be used for cannulation even if the cannula is to pass through burned tissue. The saphenous vein, however, should be avoided because of the high risk of suppurative thrombophlebitis. Should this complication occur in any peripheral vein, the entirety of the vein must be excised under general anesthesia with appropriate systemic therapy. The third most common site would be the urinary tract because of the common presence of indwelling bladder catheters for monitoring urine output. However, ascending infections and sepsis are uncommon because of the use of antibiotics for other infections and prophylaxis against infection that are commonly concentrated in the urine and thereby reduce the risk of urinary tract infection. The exception to this is the development of funguria, most commonly from Candida species. When Candida is found in the urine, systemic infection should be considered, as the organisms may be filtered and sequestered in the tubules as a result of fungemia. For this reason, blood cultures are indicated in the presence of funguria to determine the source. If the infection is determined to be local, treatment with bladder irrigation of anti- fungals is indicated. Because of the relative frequency of bacteremia/fungemia in the severely burned, sequestration of organisms around the heart valves (endocarditis) can be found on occasion. In most large burn centers, at least one case per year of infectious endocarditis will be found on a search for a source of infection. The diagnosis is generally made by the persistent finding of pathogens in the blood, most often Staphylococcus or Pseudomonas in the presence of valvular vegetations identified by echocardiography (54). This should generally be confirmed with transesophageal echocardiography if lesions are found on transthoracic echocardiography. If such a lesion is found, routine blood cultures should be performed to identify the offending organism. Treatment is primarily long-term intravenous antibiotics (12 weeks) aimed at the isolate. In the presence of a hemodynamically significant valvular lesion, excision and valve replacement Table 3 Infections in Burned Patients Burn wound infection Pneumonia Catheter-related infection Urinary tract infection Sinusitis Endocarditis Infected thrombophlebitis Infected chondritis of the burned ear 372 Wolf et al. In these cases even with appropriate treatment, mortality approaches 100% as a reflection of the severity of the burn injury. Sinusitis is a concern in burn patients because of the need for prolonged intubation of one or both nostrils with feeding tubes or an endotracheal tube (55). Treatment is generally focused on removal of the tubes if possible, and topical decongestants. Sinus puncture for a specimen should be considered if the infection is thought to be life-threatening, with systemic antibiotic treatment of the isolate. Meningitis is an uncommon infection in the burned patient, but has been found in patients with deep scalp burns involving the calvarial bone and in those with indwelling intraventricular catheters for monitoring of intracranial pressures when there are concomitant head injuries. Only in these cases should this diagnosis be considered, which can be confirmed with computed tomography of the head with intravenous contrast, or lumbar puncture. An infection that is unique to burned patients is the development of infected chondritis of the ear cartilage. When the skin of the ear is damaged by a burn, this leaves a portal of entry for microorganisms to invade the cartilage of the ear, which is relatively privileged because of a lack of vascularization. This complication occurs two to three times per year in busy burn centers and can be minimized by the use of mafenide acetate cream for treatment of ear burns. This compound diffuses into the cartilage, making it a forbidding environment for bacteria. When the complication occurs, it is characterized by a red, painful, swollen ear that has been burned with open or recently healed wounds.
These drugs relax the ureters and bladder in the urinary tract and constrict the urinary sphincter 100 mg lasix with amex. Tertiary amines can produce restlessness discount lasix 40 mg fast delivery, headache generic lasix 40mg overnight delivery, excitement discount lasix 40mg online, hallucinations, and delirium. These drugs produce anhidrosis and dry skin because of the inhibition of sympathetic cho- linergic innervation of the sweat glands. Longer-acting muscarinic-receptor antagonists (such as homatropine) are generally pre- ferred as adjuncts to phenylephrine to prevent synechia formation in anterior uveitis and iritis. Cardiovascular system uses are limited and include the administration of these drugs as a treatment for acute myocardial infarction with accompanying bradycardia and hypotension or arrhythmias (e. Urinary tract uses of atropine and other muscarinic-receptor antagonists include the adminis- tration of these drugs for symptomatic treatment of urinary urgency in inflammatory bladder disorder. Oxybutynin (Ditropan), a selective muscarinc M2-receptor antagonist, tolterodine (Detrol), a selective muscarinic M3-receptor antagonist, and trospium (Spas Max), are addi- tional agents in this class used to treat certain urinary disorders. Antimuscarinic drugs, benztropine, biperiden, trihexyphenidyl, and others, are used as adjunct to levodopa therapy for some patients with Parkinson disease (see Chapter 5). The adverse effects of muscarinic-receptor antagonists are extensions of pharmacologic activ- ity and include mydriasis, cycloplegia, dry eyes, tachycardia, dry mouth, elevated temperature, dry skin, urine retention, agitation, hallucinations, and delirium (‘‘hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter’’). Physostigmine administration for treatment of tertiary amine overdose is not recommended. Neostigmine is used to treat poisoning with quaternary muscarinic-receptor antagonists. Drug interactions of muscarinic-receptor antagonists include the production of additive effects when administered with other drugs with muscarinic-receptor antagonist activity (certain anti- depressants, antipsychotics, and antihistamines). Because of a lack of selectivity and numerous adverse effects, they are used rarely in the clinical setting (hypertensive emergencies). Classified as either nondepolarizing or depolarizing types, neuromuscular junction-blocking drugs cause neuromuscular paralysis. Nondepolarizing neuromuscular junction-blocking drugs, the prototype is tubocurarine, are arranged in a bulky, rigid conformation. These agents prevent depolarization of the muscle and propagation of the action potential. Nondepolarizing agents are administered parenterally and are generally used for long-term motor paralysis. Nondepolarizing agents have durations of action that range from 20–90 minutes, which can be extended by supplemental fractional dosing and is increased by larger initial doses (although this also increases the likelihood of adverse effects). Most nondepolarizing agents are metabolized by the liver or are excreted unchanged. Tubocurarine (prototype), an isoquinoline derivative, is seldom used clinically at this time. It has the same properties, but with less histamine release and thus less hypotension and bronchoconstriction. Chapter 2 Drugs Acting on the Autonomic Nervous System 39 table 2-7 Properties of Some Skeletal Muscle Relaxants Nondepolarizing Duration of Ganglion Histamine Cardiac Muscarinic Agent Action Blockade Release Receptors Comments Tubocurarinea Long + ++ — Prototype Metocurinea Long + + — Less hypotension and broncho- constriction than tubocurarine Atracuriuma Intermediate — + — Inactivated spontaneously in plasma; laudanosine, a break- down product, may cause seizures. Pancuroniumb Long — — ++ Increased heart rate Vecuroniumb Intermediate — — — Metabolized by liver Depolarizing Agent Succinylcholine Very short ++ + ++ Hydrolyzed by cholinesterase; malignant hyperthermia is a rare, potentially fatal complication aIsoquinoline derivative. It is inactivated spontaneously in plasma by nonenzymatic hydrolysis that is delayed by acidosis. Its duration of action is reduced by hyperventilation-induced respiratory alkalosis. Other available isoquinoline derivatives similar to atracurium include short-acting (10–20 min) mivacurium (Mivacron), which is rapidly hydrolyzed by plasma cholinesterase (pseu- docholinesterase), has a short duration of action, and produces moderate histamine release at high doses, and doxacurium (Nuromax), which is stable in plasma, has a long duration of action (90–120 min), is excreted unchanged, and is devoid of vagolytic activity. Pancuronium (Pavulon) (1) Pancuronium has a steroid nucleus with two attached quaternary amine groups. Vecuronium (Norcuron) (1) Vecuronium is a steroid derivative that has an intermediate duration of action (30–40 min). Rocuronium (Zemuron) is a derivative of vecuronium with an intermediate duration of action (30–40 min) that undergoes primarily hepatic clearance (75%–90%).
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