Principles of office anesthesia: part II. Topical anesthesia

The development of topical anesthetics has provided the family physician with multiple options in anesthetizing open and intact skin. The combination of tetracaine, adrenaline (epinephrine), and cocaine, better known as TAC, was the first topical agent available for analgesia of lacerations to the face and scalp. Cocaine has been replaced with lidocaine in a newer formulation called LET (lidocaine, epinephrine, and tetracaine). For analgesia to nonintact skin, LET gel is generally preferred over TAC because of its superior safety record and cost-effectiveness. EMLA (eutectic mixture of local anesthetics) is perhaps the most well-known topical anesthetic for use on intact skin. EMLA can be used to anesthetize the skin before intramuscular injections, venipuncture, and simple skin procedures such as curettage or biopsy. To be fully effective, EMLA should be applied at least 90 minutes before the procedure. ELA-Max is a new, rapidly acting topical agent for intact skin that works by way of a liposomal delivery system and is available over the counter. Other delivery vehicles for topical anesthesia currently in development, including iontophoresis and anesthetic patches, may one day give patients and physicians even more flexibility.     

The effects of spinal anesthesia vs epidural anesthesia on 3 potential postoperative complications: pain,urinary retention,and mobility following inguinal herniorrhaphy

This study was conducted to determine the effects of spinal (n = 113) vs epidural (n = 31) anesthetic techniques on 3 common postoperative complications: pain, urinary retention, and mobility for patients undergoing inguinal herniorrhaphy. The study design was a retrospective chart review. Data were collected on 144 subjects who underwent herniorrhaphy between January 1 and December 31, 1999, had an ASA classification of I to III, and were older than 18 years. The local anesthetics used to provide spinal anesthesia were 5% lidocaine, 0.75% bupivacaine, and 1% tetracaine solutions. The anesthetics used to provide epidural anesthesia were a solution of 2% lidocaine with epinephrine or 3% chloroprocaine with epinephrine. Results revealed that pain was not significantly different between the 2 anesthetic groups (P = .65); however, subjects in the epidural anesthesia group were able to ambulate (P = .008) and void (P = .02) sooner than subjects in the spinal anesthesia group. This study demonstrates that epidural anesthesia results in less urinary retention and earlier mobility than spinal anesthesia in men undergoing inguinal herniorrhaphy. Minimizing postoperative complications is essential in order for the nurse anesthetist to provide a satisfactory anesthetic experience. This study's findings suggest that epidural anesthesia optimizes recovery for the patient undergoing inguinal herniorrhaphy.     

Regional anesthesia for office procedures: part I. Head and neck surgeries

Although local anesthesia usually is used in surgical procedures, field or nerve blocks can provide more effective anesthesia in some situations. In a field block, local anesthetic is infiltrated around the border of the surgical field, leaving the operative area undisturbed. In field blocks, epinephrine may be added to the anesthetic to enhance vasoconstriction and prolong the duration of anesthesia. In a nerve block, anesthetic is injected directly adjacent to the nerve supplying the surgical field. A review of regional anatomy and the location of nerves and other important structures is essential before administering the injection. Systemic toxicity is rare with regional anesthesia and can be prevented by using the smallest dose possible and aspirating before the injection. Supraorbital, supratrochlear, infraorbital, and mental nerve blocks can provide adequate anesthesia in procedures on parts of the face. Field block also may be considered when operating on the ear or lips.     

Permanent Neurologic Symptoms after Prolonged Epidural Analgesia

Objective: Although transient neurologic symptoms may occur after neuraxial anesthetics with lidocaine, permanent neurologic symptoms (PNS) are unusual after uncomplicated continuous epidural analgesia (CEA). This report demonstrates that PNS may follow CEA uncomplicated by paresthesias, dural puncture, spinal hemorrhage, or intravascular local anesthetic injection; and performed with bupivacaine alone administered at high dosages with vasoconstrictors over a prolonged time period. Case Report: An obstetrical patient developed fixed left L5‐S1 sensorimotor radiculopathy following L5‐S1 level CEA with bupivacaine alone administered at high doses (270 mg) with a vasoconstrictor (epinephrine, 225 mg) over a prolonged time period (62 hours). Conclusions: CEA should be administered at higher lumbar levels for labor analgesia rather than at lumbosacral levels that may require higher volumes and concentrations of local anesthetics with greater potential for local anesthetic neurotoxicity. Local anesthetics with vasoconstrictors should only be used as sentinel markers of unrecognized intravascular entry, rather than as primary local anesthetics during CEA to avoid any potential for ischemic neuropathy.     

Monitoring of skin conductance in anesthesiology and intensive care

The purpose of the study is to examine the efficacy and safety through the introduction of a local anesthetic wound irrigation catheter for continuous postoperative analgesia in newborns. The study was conducted during the postoperative period of 33 full-term newborns. In the study group (n = 15), analgesia was carried out through the wound catheter with infusion of local anesthetic, for the control group (n = 18) continuous intravenous infusion promedol was used. The effectiveness of postoperative analgesia was rated by CRIES postoperative pain control scale, monitoring of skin conductance, cardiointervalogram and hormone level control in the blood. The study showed that the use of wound catheter for continuous postoperative analgesia with local anesthetics provides effective level of analgesia in newborns, which is comparable with the introduction of opioid analgesics. There were no severe postoperative complications. The method of analgesia by administering a local anesthetic through the wound catheter can be recommended for postoperative analgesia in newborns, especially during major surgeries.     

A double-blind comparison of a supplemental interligamentary injection of fentanyl and mepivacaine with 1:200,000 epinephrine for irreversible pulpitis

The analgesic efficacy of supplemental interligamentary fentanyl injection for management of endodontic debridement patients was investigated through a randomized, double-blind study. Forty patients who presented with acute symptomatic irreversible pulpitis of the upper first molar tooth participated in the study. Patients were scheduled for endodontic debridement, for which infiltration anesthesia with 1.8 ml of 2% mepivacaine with epinephrine 1:200,000 was the standard primary anesthetic technique. Patients were randomly divided into two equal groups. The first group received supplemental interligamentary injection with 0.4 ml fentanyl 0.05 mg/ml, while the second group received supplemental interligamentary injection with 0.4 ml mepivacaine with epinephrine 1:200,000. The intraligamental-injected drug was given as 0.2 ml on the mesial and 0.2 ml on the distal aspect of the tooth. Results indicated that fentanyl provided relatively greater analgesia, yielding satisfactory relief during different stages of the procedure, including access cavity preparation, pulpotomy, and pulp extirpation. Fentanyl is effective when used in conjunction with local anesthetics to provide adequate analgesia during endodontic debridement, and this finding provides strong evidence that peripheral actions are involved in the analgesia produced by opioid drugs in inflammatory pain.     

Evidence-based anesthesia: fever of unknown origin in parturients and neuraxial anesthesia

The safety of neuraxial analgesia in febrile patients is controversial. We performed an evidenced-based project in an effort to establish a guideline for our active obstetric clinical practice. Neuraxial anesthesia is generally safe for parturients, and complications are rare; however, serious adverse outcomes can result. Because of the devastating nature of the morbidity, the decision to proceed with a neuraxial anesthetic in the face of infection may be contentious. Fever and sepsis are considered relative contraindications to regional anesthesia; however, epidural anesthesia is a superior method of management of pain during labor. One must also consider that 30% to 40% of patients with chorioamnionitis require cesarean delivery. Because of the increased morbidity and mortality of general anesthesia in this population, it may be reasonable to proceed with regional anesthesia. Based on a review of the literature, it is difficult to estimate the risk of an infrequently occurring event. We recommend evaluation of each individual to determine the risks and benefits of the anesthetic. However, it is prudent to administer antibiotics before the regional anesthetic and adhere to strict aseptic technique. Postprocedure monitoring is essential for early detection and treatment of complications.     

Intrathecal bupivacaine and morphine toxicity leading to transient hypotension and delayed status epilepticus

BackgroundLocal anesthetic systemic toxicity characteristically occurs after inadvertent intravascular injection of local anesthetics; however, it is unclear if similar symptoms arise after intrathecal adminstration. Intrathecal use of local anesthetics for chronic pain is increasing and carries a potential risk of toxicity. Experience with the presenting symptoms and appropriate treatment for intrathecal local anesthetic toxicity is limited.Case studyA 74-year-old woman with an intrathecal bupivacaine/morphine pump developed lower extremity sensory neuropathy followed by obtundation, hypotension, and lower extremity flaccidity after an intrathecal pump refill. Her condition evolved to status epilepticus (SE) refractory to standard treatment. Intravenous fat emulsion (IFE) was administered, but was not immediately effective thus necessitating phenobarbital loading and propofol infusion. Despite significant bupivacaine neurotoxicity, no cardiotoxicity developed.DiscussionThe patient developed intrathecal local anesthetic and opioid toxicity after a malfunction of her intrathecal pump during a refill. We hypothesize that no cardiotoxicity developed secondary to sequestration of bupivacaine within the central nervous system. Likewise, poor CNS penetration of intravenous lipid emulsion may have negated or delayed any antidotal effect.ConclusionWe present a case of intrathecal toxicity leading to prolonged spinal anesthesia, progressive encephalopathy, and SE refractory to intravenous lipid emulsion. Management of SE with benzodiazepines and barbiturates may be more effective than lipids in cases of toxicity from intrathecal administration of bupivacaine.     

Kaudalan?sthesie bei Kindern

Caudal block is a safe procedure commonly used for pediatric perioperative analgesia. Complications are extremely rare but nevertheless local and systemic contraindications must be excluded. Optimal safety and quality result when strict attention is paid to technical details. A local anesthetic (LA) containing epinephrine allows early detection of inadvertent intravascular LA administration; therefore an epinephrine/LA mixture is recommended at least for the test dose. In terms of safety the choice of LA itself is probably of secondary importance. Clonidine as an adjuvant has an excellent risk/benefit profile with minimal side effects. Inadvertent systemic LA intoxication is a rare but potentially fatal complication of regional anesthesia and measures for prevention and early detection are essential. Should circulatory arrest occur, immediate resuscitation following standard guidelines is to be initiated including the use of epinephrine as the first line drug. Intravenous administration of lipid solutions may be beneficial as a secondary adjunct to stabilize hemodynamics but is not an alternative to epinephrine.     

Use of local anesthesia for arterial punctures.

BACKGROUND: Except for intravenous therapy, arterial access is the most common invasive procedure performed on critically ill patients. Arterial puncture is a source of pain and discomfort. Intradermal injection of lidocaine around the puncture site decreases the incidence and severity of localized pain when used before arterial puncture. OBJECTIVE: To review the recommendations and studies related to the use of intradermal lidocaine to decrease pain during arterial punctures. METHODS: Articles were identified by doing a systematic computerized search of MEDLINE (1980 to January 2006) to evaluate articles and reference lists of articles and a manual search of the references listed in original and review articles. English-language articles that evaluated any aspect of pain related to arterial puncture and cannulation, pain related to and methods of introducing lidocaine subcutaneously, and perceptions and use of local anesthesia for arterial or intravenous punctures were reviewed. RESULTS: Except among anesthesia providers, the use of a local anesthetic before arterial puncture is not universal, contrary to the standard of practice. A number of false perceptions may prevent wider use of such anesthetics. CONCLUSION: Before a plan for behavior modification or policy change is recommended for use of local anesthesia to decrease pain associated with arterial puncture, further research must be done to determine nurses' perceptions of use, actual practice, and currently established local policies.     

Naphazoline and oxymetazoline are superior to epinephrine in enhancing the cutaneous analgesia of lidocaine in rats

This study observed the cutaneous analgesic effect of adrenergic agonists when combined with lidocaine. We aimed at the usefulness of four adrenergic agonists and epinephrine as analgesics or as tools to prolong the effect of local anesthetics using a model of cutaneous trunci muscle reflex (pinprick pain) in rats. We showed that subcutaneous four adrenergic agonists and epinephrine, as well as the local anesthetic bupivacaine and lidocaine, developed a concentration-dependent cutaneous analgesia. The rank order of the efficacy of different compounds (ED₅₀; median effective dose) was epinephrine [0.013 (0.012–0.014) μmol] > oxymetazoline [0.25 (0.22–0.28) μmol] > naphazoline [0.42 (0.34–0.53) μmol] = bupivacaine [0.43 (0.37–0.50) μmol] > xylometazoline [1.34 (1.25–1.45) μmol] > lidocaine [5.86 (5.11–6.72) μmol] > tetrahydrozoline [6.76 (6.21–7.36) μmol]. The duration of full recovery caused by tetrahydrozoline, oxymetazoline, or xylometazoline was greater (P < 0.01) than that induced via epinephrine, bupivacaine, lidocaine, or naphazoline at equianesthetic doses (ED₂₅, ED₅₀, and ED₇₅). Co-administration of lidocaine (ED₅₀) with four adrenergic agonists or epinephrine enhanced the cutaneous analgesic effect. We observed that four adrenergic agonists and epinephrine induce analgesia by themselves, and such an effect has a longer duration than local anesthetics. Co-administration of lidocaine with the adrenergic agonist enhances the analgesic effect, and the cutaneous analgesic effect of lidocaine plus naphazoline (or oxymetazoline) is greater than that of lidocaine plus epinephrine.     

Maternal paraparesis after epidural anesthesia and cesarean section

Continuous epidural infusion of local anesthetics containing epinephrine has become increasingly popular. This technique has been associated with few, if any, complications. We have presented a case of anterior spinal artery syndrome with paraparesis after continuous lumbar epidural infusion of an anesthetic during labor and subsequent emergency cesarean section.     

Pharmacological and physiological specificities of local anesthesia in dentistry

Described in the paper are the specificity of local analgesia at the medical dental procedures and the effect produced by local anesthetics and vasoconstrictive agents on the induction of nervous fibers and peripheral blood circulation. The pharmacological-and-physiological mechanisms of local analgesia by a 2% artikain solution (with adrenalin, concentration 1:100,000) and by a 2% mepivakain solution (with adrenalin, concentration 1:100,000) exerted on the pain sensitivity and blood circulation in the tooth pulp are analyzed.     

How pharmacokinetic can help to choose the right local anesthetics during epidural infusion

Local anesthetics (LA) are used for the prevention and relief of both acute and chronic pain. The local anesthetic molecule consists of three components; each of these contributes distinct properties to the molecule. The onset of action is determined by tissue pH, the pKa of the particular agent used, and the amount of nonionized drug available in the tissue. The duration of action depends on the length of time that the drug binds to the membrane. Most local anesthetics were produced as enantiomeric mixtures known as racemates, although it is recognized that each enantiomer possesses quite different pharmacological properties. All amide-type local anesthetics, except for lidocaine, contain a chiral center, meaning that two enantiomers exist. Enantiomers have the same physicochemical properties and differ only in the way that they rotate plane-polarized light. However, their biological behavior, in terms of pharmacokinetic and pharmacodynamic characteristics, can be very different. The clinical response to a particular local anesthetic or its toxicity may vary substantially from patient to patient; dosing often requires careful titration. Interindividual variability is caused by several factors including the pharmacokinetics features of the drug, pharmacodynamic properties or patient’s characteristics.     

Interpleurale Katheteranalgesie

Interpleural analgesia is a method of postoperative analgesia that was developed by Kvalheim and Reiestad in 1984. The main indication is postoperative pain after unilateral thoracic and upper abdominal surgery. Many authors report good analgesic effects and better postoperative lung function following cholecystectomy. There is some controversy on the effectiveness of this method after thoracic surgery. Further indications are post-traumatic pain after multiple rib fractures and chronic pain in the upper abdomen (carcinoma of the pancreas, chronic pancreatitis). The local anaesthetic of choice is bupivacaine (in concentrations of 0.25-0.75%, injection volumes of 10-40 ml, with or without epinephrine, applied as bolus or infusion), but others, such as lidocaine or morphine, are also being tested. Risks involved in this method are pneumothorax when the catheter is placed blind and the systemic toxicity of the local anaesthetic. This review provides information on the mechanism of action, the technique, the clinical use to date and possible risks.     

The Effects of Local Anesthetics on Postoperative Pain

This study was performed to determine if intraoperative local anesthesia improved control of postoperative pain after inguinal herniorrhaphy and to compare the effects of two commonly used local anesthetics on pain management. The Gate Control Theory of Pain formed the theoretical basis for this study. A retrospective nonexperimental study in an ex post facto design was used. Data were collected from 1990 through 1997 on 120 patient charts. The use of local anesthetic intraoperatively significantly decreased patients' lengths of stay postoperatively (P = 0.00) and need for postoperative narcotics (P = 0.00). Bupivacaine was found to be superior to lidocaine in decreasing the need for postoperative narcotic analgesia. Researchers concluded that many patients would benefit from intraoperative injection of local anesthesia. This information can affect patient care outcomes through decreasing recovery time, reducing postoperative pain, and reducing health care costs.     

Der postoperative Schmerz

A short survey about the different methods available for producing postoperative analgesia is given, the goal being to make it clear to the clinician that there are quite a number of techniques to be used although the everyday clinical practice often sticks to simple and not too effective methods of pain treatment following surgery. Initially presenting short informations about the neurophysiology of pain and the pathogenesis and causes of postoperative pain two main groups of producing analgesia are then discussed.Thefirst group deals with the systemic use of analgesics be it nonnarcotic analgesic antipyretics or narcotic analgesics (opioids). As for the first subgroup the peripheral action of these drugs (metamizol, acetylsalicylic acid, paracetamol) is brought about by blocking the synthesis of prostaglandins. These substances can only be used for very moderate postoperative pain f.i. following head and neck surgery. The strong acting opioids belong to the second subgroup. Recent informations on receptor sites in the brain and cord and the subgrouping of the receptors throws new light on the understanding of the different effects of these drugs and on the pathomechanisms of agonistic, antagonistic and mixed activities. The clinically used opioids then are mentioned (morphine, fentanyl, methadon, pethidin, piritramide, tilidin, buprenorphin and pentazocine) and dosage, duration of action, antagonisms and untoward side effects are presented. Stress is laid on the recent development of patient-controlled analgesia with all its advantages. Thesecond main group of methods for postoperative analgesia consists of regional anesthesia techniques as there are brachial plexus block, intercostal block and the continuous epidural analgesia using both local anesthetics and spinal opioids. The brachial plexus block in continuous form is absolutely able to prevent pain after operations in the shoulder-arm-region and can be prolonged even for weeks using catheter techniques. The intercostal block on the other hand practically can be performed only as single injection technique being relatively simple however from the technical point of view. The catheter epidural analgesia is the most important method within this group. In comparison to the centrally acting opioids the epidural technique brings some distinct advantages especially in the cardiorespiratory risk case. Choosing between "top up"-technique and continuous infusion of the local anaesthetic depends on the individual circumstances the latter method apparently giving a more steady level of analgesia. The spinal opioid techniques finally gain more and more importance during the last years. They present clear advantages over the local anesthetic methods as there are the long lasting analgesia and the selective blockade of pain not touching motor and sympathetic nerve fibers. A delayed respiratory depression however might be a serious danger showing an incidence of 0,3% in the epidural and some 10% in the subarachnoid route. Aiming to inform the clinician once again about the vast field of possibilities available to make the postoperative course painfree it is hoped that this important task in the postoperative period will be handled with more consequence and effectivity in the future.     

Intrathecal therapy for the management of cancer pain

Inadequately managed cancer pain continues to be a significant problem despite increased awareness, improved knowledge and understanding of pain pathophysiology, and standardized treatment guidelines of this distressing and debilitating symptom complex. Small subsets of patients who are refractory to optimal medical management because of drug toxicity or unsatisfactory analgesia may be candidates for exteriorized or implantable intrathecal drug delivery systems. By delivering opioids and other agents directly to the central nervous system, intrathecal drug administration can offer superior pain relief with less toxicity at a fraction of the systemic dose. With adjuncts such as local anesthetics and clonidine, intrathecal therapy also allows for broader therapeutic options in the most difficult of cases. In general, intrathecal therapy is underused despite evidence of its efficacy, safety, and cost-effectiveness.     

Efficacy of drugs in regional anesthesia: A review

Local anesthetics and opioids are the most commonly used drugs in regional anesthesia. Several other drugs are used as adjuvants in addition to local anesthetics.We will review the drugs currently used in regional anesthesia. In April 2009 we searched the PubMed database and found 143 articles related to the clinical use of drugs in regional anesthesia; we divided them into 3 major chapters: local anesthetics, opioids and adjuvants.Among local anesthetics, ropivacaine and levobupivacaine can be considered the drugs of choice in neuraxial and peripheral techniques because their toxicity is low even in large volume administration; mepivacaine can be considered the drug of choice in peripheral techniques when a shorter blockade is needed.Sufentanil is the opioid of choice in both neuraxial and peripheral techniques because it appears to improve the quality of anesthesia and to prolong sensory blockade in the postoperative period.Among the adjuvants to local anesthetics, clonidine is by far the most used drug in regional anesthesia; its yield in improving and prolonging the effects of local anesthetics is apparent in neuraxial techniques. Other drugs have been studied as adjuvants to local anesthetics but clinical evidence of their benefit is controversial in many cases and further trials are unquestionably warranted.In conclusion, since many different drugs are available for regional anesthesia, we must choose wisely the one that exhibits the best safety-efficacy profile and that suits the chosen technique and type of anesthesia/analgesia best.     

Caudal anesthesia and its determinant factors

In 130 surgical patients with diseases and injuries in the area of the perineum and lower extremities the clinical effects of three modern local anesthetics: 2% solution of lidocaine, 0.5% solution of bupivacaine, 0.75% solution of ropivacaine and their combinations (2% lidocaine and 0.25% bupivacaine solution 2% lidocaine and ropivacaine 0.375% solution) were followed with regard to the influence of increasing volumes of local anesthetics and different rates of drug administration. It is established that an effective caudal anesthesia is provided with all modern local anesthetics, with increasing use of local anesthetic solution to 40 ml provides duration and the prevalence of sensory and motor blocks, the use of mixture of local anesthetics optimizes the development and maintenance of the caudal blockade.