Local infiltrative injection

Local infiltration anesthesia is die injection of a local anesthetic druginto tissues. This type of anesfliesia may be used for dental procedures, die suturing of small wounds, or making an incision into a small area, such as that required for removing a superficial piece of tissue for biopsy. 

In a report from the Boston Collaborative Drug Surveillance Program, pediatric nurses have reported a much higher frequency of complications from IM injections than that observed in the adult population. Twenty-three percent of pediatric nurses surveyed had observed complications (local pain, abscess, hematoma) versus a rate of 0.4% reported in adult patients [86]. Serious complications, such as paralysis from infiltration of the sciatic nerve, quadriceps myofibrosis, and accidental intra-arterial injection, are usually the... 

Forms of local anesthesia. Local anesthetics are applied via different routes, including infiltration of the tissue (infiltration anesthesia] or injection next to the nerve branch carrying fibers from the region to be anesthetized (conduction anesthesia of the nerve, spinal anesthesia of segmental dorsal roots), or by application to the surface of the skin or mucosa (surface anesthesia]. In each case, the local anesthetic drug is required to diffuse to the nerves concerned from a depot placed in the tissue or on the skin. 

Extravasation Extravasation of IV hypertonic solutions of sodium bicarbonate may cause chemical cellulitis (because of their alkalinity), with tissue necrosis, ulceration, or sloughing at the site of infiltration. Prompt elevation of the part, warmth, and local injection of lidocaine or hyaluronidase are recommended to prevent sloughing. 

Infiltration anaesthesia is applied fan-shaped, with as few needle punctures as possible, in close proximity of the wound or the skin area to be treated. An aspiration should always take place to avoid intravascular injection. Suitable alternatives are lidocaine (lignocaine) or prilocaine for injection 5-10 mg/ml, with or without adrenaline. When making an incision of an abscess it is sometimes difficult to use a local anaesthetic if there is a pronounced inflammatory reaction, since the effect of the anaesthetic is reduced due to an increased acidity level. While adrenaline reduces bleeding and delays dispersion of the anaesthetic, local anaesthetic/adrenaline combinations are contraindicated for local anaesthesia of digits, on the face or where the skin survival is at risk. 

The rate of absorption of a local anesthetic into the bloodstream is affected by the dose administered, the vascularity at the site of injection, and the specific physicochemical properties of the drug itself. Local anesthetics gain entrance into the bloodstream by absorption from the injection site, direct intravenous injection, or absorption across the mucous membranes after topical application. Direct intravascular injection occurs accidentally when the needle used for infiltration of the local anesthetic lies within a blood vessel, or it occurs intentionally when Udocaine is used for the control of cardiac arrhythmias. 

Infiltration (i.e., the injection of local anesthetics under the skin) of the surgical site provides adequate anesthesia if contiguous structures are not stimulated. Since the onset of local anesthesia is rapid, the surgical procedures can proceed with little delay. Minimally effective concentrations should be used, especially in extensive procedures, to avoid toxicity from overdosage. 

Infiltration anesthesia— relatively nonspecific injection of the local anesthetic into the skin and deeper tissues of the area to be anesthetized... 

Lignocaine injections are indicated for production of local or regional anaesthesia by infiltration techniques such as percutaneous injection, peripheral nerve block, spinal or subarachnoid block. 

Local anaesthetics can be applied topically, deposited around peripheral nerves, or infiltrated into tissues. Central neural blockade can be produced by injection into the subarachnoid or epidural spaces. Less common uses are for intravenous regional anaesthesia and attenuation of cardiovascular responses to tracheal intubation. The membrane-stabilising effect of local anaesthetics has been utilised in the treatment of myocardial arrhythmias. 

Lidocaine (synonyme lignocaine) was introduced as the first amide in 1944 and is the most commonly used LA today. It has a rapid onset of action with intermediate duration and an intermediate toxicity. The maximum tolerated dose with infiltration or injection is 200 mg (500 mg when combined with adrenaline). Lidocaine is dealkylated in the liver to monoethylglycine xylidide and glycine xylidide which retain local anesthetic activity. It is available in a variety of preparations including creams, gels, patches and solutions, often in combination with adrenaline. 

This consists in the injection of the local anesthetic into or around the nerve trunk or in the area of its distribution, so as to block off sensory impulses from the operative field. Because fatal effects may arise from the absorption of the anesthetic, the smallest amount of the least-toxic agent that is effective should be employed, under conditions that minimize absorption. Procaine with the addition of epinephrine (1 100,000) is generally preferred. A well-planned technique is important. It is not necessary to flood the entire field of operation, as in the earliest methods, nor even to infiltrate the whole line of incision, as in infiltration anesthesia. It is now aimed at confining the anesthetic mainly to the nerves, by placing it where the nerves chiefly run or injecting it into the nerves themselves. 

The local injection of 0.1 to 2% procaine or other anesthetics blocks the centripetal proprioceptive impulses and thereby relaxes muscular tonus, normal and abnormal, such as spasmodic torticollis. It effects almost instantaneous relief of the pain, stiffness, malposition, and incapacity of fibrositis, lumbago, and acute sprains and fractures. The site of greatest tenderness may be infiltrated with 10 to 30 cc of 1 or 2% procaine hydrochloride. Injected systemically, it relaxes traumatic tetanus and removes decerebrate rigidity, so that spontaneous movements of the limbs and of the respiration return. Its curare action may also be concerned in this effect. It relaxes parkinsonian, but not myotonic, rigidity. 

Infiltration anesthesia is the injection of local anesthetic directly into tissue without taking into consideration the course of cutaneous nerves. Infiltration anesthesia can be so superficial as to include only the skin. It also can include deeper structures such as intra-abdominal organs when these too are infiltrated. The advantage of infiltration anesthesia and other regional anesthetic techniques is that it is possible to provide satisfactory anesthesia without disruption of normal bodily functions. 

Infiltration anesthesia The injection of local anesthetic directly into tissue without taking into consideration the course of cutaneous nerves duration can be extended with the addition of epinephrine (vasoconstrictor)... 

One generally has to distinguish between surface anesthesia, infiltration anesthesia and conduction anesthesia (Fromherz 1922 Schaumann 1938 Camougis Tak-man 1971). Special local tolerance tests have been developed for each of these applications including peridural and intrathecal injections. 

Local anesthetics containing an amide linkage are metabolized principally by the liver.Thus, patients with hepatic disease may be more likely to exhibit toxic effects from the injectable anesthetics. Local tissue infiltration or nerve blocks should be avoided or performed using minimally effective anesthetic doses in patients with hepatitis, cirrhosis, extrahepatic obstruction (e.g., lithiasis), or other clinically significant hepatic dysfunction. 

Pharmacokinetics. The distribution rate of a single dose of a local anaesthetic is determined by diffusion into tissues with concentrations approximately in relation to blood flow (plasma t] only a few minutes). By injection or infiltration, local anaesthetics are usually effective within 5 min and have a useful duration of effect of 1-1.5 h, which in some cases may be doubled by adding a vasoconstrictor (below). 

Localized cntaneous lesions were sometimes noted after snbcntaneons injection and mimicked those described with GM-CSF. Injection-site subcutaneous nodules infiltrated by lenkemic cells have been found in patients treated for acnte leukemia (SEDA-19, 343), but in two other patients, inflammatory macrophages were misinterpreted as malignant cells (SEDA-20, 337). 

Systemic toxicity is most likely to occur if a local anesthetic is accidentally injected into a vessel in sufficient quantity (7). Even with appropriate local administration, there is inevitably some diffusion of the local anesthetic into the body from the site at which it is applied, varying with local blood flow and the technique intercostal block, for example, rapidly produces high plasma concentrations, while subcutaneous infiltration leads to much lower concentrations more slowly. The amount of local anesthetic used is another contributory factor. 

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