Sympathetic hyperactivity, respiratory failure, pruritus, and anesthesia after unintentional epidural injection of potassium chloride: Case report

Background and Objectives. A combination of epidural and general anesthesia has been widely used to attenuate the surgical stress response and to provide postoperative analgesia. This case report illustrates the use of this anesthetic technique. Analgesia was induced with local anesthetic in the immediate postoperative period using unintentional 19.1% potassium chloride (KCI) as diluent. Methods. An ASA I male patient was scheduled for surgical correction of idiopathic megaesophagus under continuous epidural anesthesia combined with general anesthesia. In the postoperative period, while preparing 10 mt 0.125% bupivacaine to be administered through the epidural catheter for pain control, 5 mt 19.1% KCI was unintentionally used as diluent, resulting in a 9.55% potassium solution concentration. Results. The patient developed warmness of the lower limbs, tachycardia, hypertension, intense pruritus on the chest, agitation, exacerbation of sensory and motor blocks, and respiratory failure secondary to pulmonary edema, requiring ventilatory support. Total recovery was observed after 24 hours. Conclusions. Epidurally injected potassium leads to severe clinical manifestations caused by autonomic dysfunction, spinal cord irritation, and possible release of histamine. Despite continuous recommendations, ampule misidentification still happens in hospitals, frequently leading to serious accidents.

EFFECTS OF LIDOCAINE INJECTIONS INTO THE LATERAL PARABRACHIAL NUCLEUS ON DIPSOGENIC AND PRESSER RESPONSES TO CENTRAL ANGIOTENSIN-II IN RATS

This study investigated the effects of bilateral injections of the local anesthetic, lidocaine, into the lateral parabrachial nucleus (LPBN) on the dipsogenic and presser responses induced by intracerebroventricular (i.c.v.) injection of angiotensin II (ANG II). Centrally injected ANG II (50 ng/l mu l) induced water intake (10.2 +/- 0.8 ml/h) and presser responses (22 +/- 1 mmHg). Prior bilateral injection of 10% lidocaine (200 nl) into the LPBN increased the water intake (14.2 +/- 1.4 ml/h), but did not change the presser response (17 +/- 1 mmHg) to i.c.v. ANG II. Lidocaine alone injected into the LPBN also induced a presser response (23 +/- 3 mmHg). These results showing that bilateral LPBN injection of lidocaine increase water intake induced by i.c.v. ANG II are consistent with electrolytic and neurotoxic lesion studies and suggest that the LPBN is associated with inhibitory mechanisms controlling water intake induced by ANG II. These results also provide evidence that it is feasible to reversibly anesthetize this brain area to facilitate fluid-related ingestive behavior.

Histological evaluation of the response of apical tissues to glass ionomer and zinc oxide eugenol based sealers in dog teeth after root canal treatment

The object of the study was to compare two commercial root canal sealers: Ketac-Endo (a glass ionomer cement) and Fill Canal (a zinc oxide-eugenol cement). A total of 34 root canals from dog premolars with vital pulps were used. After instrumentation, the root canals were sealed with Ketac-Endo and Fill Canal cements using gutta-percha and a lateral condensation technique. After 270 days the animals were sacrificed with an anesthetic overdose and the maxillae and mandibles were removed and fixed in formalin for 48 h. After routine histological processing the sections were stained with hematoxylin-eosin and Mallory trichrome stains. Microscopic analysis revealed that Ketac-Endo cement presented better results than Fill Canal cement.

Initial Development and Characterization of PLGA Nanospheres Containing Ropivacaine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Langmuir films of an amide extracted from Piperaceae and its interaction with phospholipids

In this work, we investigate Langmuir monolayers froth an amide extracted from dried roots of Ottonia propinqua, a native Brazilian plant believed to exhibit anesthetic and hallucinogen activities. In addition to producing monolayers from the amide itself, we probe the molecular-level action of the amide on phospholipids employed as simple membrane models. The surface pressure-molecular area (pi-A) isotherms for the amide were little affected by a number of subphase conditions. Almost no changes were observed upon varying the compression speed, spreading volume onto the surface, ions in the subphase, ionic strength and the solution solvent. However, stronger effects occurred when the subphase temperature and pH were altered, as the isotherms were shifted to larger areas with increasing temperatures and decreasing pHs. These results are discussed in terms of the molecular packing adopted by the amide at the air-water interface. In the mixed films with arachidic acid, the area per molecule varied linearly with the concentration of amide, probably due to phase separation. on the other hand, in the mixed films with dipalmitoyl phosphatidyl choline (DPPC), small amounts of the amide were sufficient to change the pi-A isotherms significantly. This points to a strong molecular-level interaction, probably between the phosphate group in the zwitterion of DPPC and the nitrogen from the amidic group. (c) 2004 Elsevier B.V. All rights reserved.

Lidocaine effects on corneal endothelial cell ultrastructure

The purpose of this study was to determine whether intracameral commercial lidocaine 2% induces alterations on the rabbit corneal endothelium. Forty white rabbits received different substances inside the anterior chamber: group (G)1, no substance; G2 and G3 received lidocaine 2% with preservative in aqueous solution; G4 and G5, lidocaine 2% with preservative in gel solution; G6 and G7, the anesthetic preservative (metilparahydroxybenzoate 0.1%); and G8 and G9, lidocaine 2% without preservative in aqueous solution. The animals from G2, 4, 6 and 8 were sacrificed after 1 h, and from G3, 5, 7 and 9 after 24 h after injection of the substance inside the anterior chamber. The corneas were clinically evaluated and assessed by transmission and scanning electron microscopy. G1, 2, 6, 7, 8 and 9 animals had very similar characteristics in clinical, ultrastructural and morphometric evaluations; the G3 and G4 animals showed discrete edema and one animal in G5 had intense corneal edema. We conclude that lidocaine 2% with preservative induces few ultrastructural alterations in the corneal endothelial cells.

Cauda equina syndrome after spinal tetracaine: Electromyographic evaluation-20 years follow-up

CAUDA equina syndrome (CES) has long been recognized as a rare complication of spinal anesthesia.(1) CES has been described after administration of spinal anesthetics with lidocaine(2) and bupivacaine.(3) In 1991,(4) CES was reported after continuous spinal anesthesia with 1% tetracaine. In 1980, at our university hospital, six adult female patients underwent perineal gynecologic surgery using a spinal anesthetic of 2 ml tetracaine, 1.2%, in 10% glucose. The concentration of the injected tetracaine was unknown by the anesthetists. In all cases, lumbar puncture was performed at the L3-L4 interspace with a disposable spinal needle while the patients were in the sitting position. CES was first diagnosed 72 h or later postoperatively; previous diagnosis was not possible because patients had an indwelling urethral catheter. The diagnosis of CES was confirmed in all patients. During the past year, after institutional approval and informed consent, clinical, magnetic resonance imaging, electromyographic examinations, and conduction studies were performed in three of the above patients. Examinations were not possible on the other three patients because one had recently died, another could not be located, and the third refused to participate. T1 and T2 magnetic resonance image readings were obtained with Gadolinium contrast from a 0.5 Tesla General Electric apparatus (General Electric, Tokyo, Japan). Bilateral sensory and motor conduction studies of the sciatic nerve branches were obtained using a two-channel Nihon-Kohden Neuropack 2 (Nihom-Kohden Corporation, Tokyo, Japan). Electromyography was performed in accordance with conventional techniques.(5,6)

Benzocaine loaded biodegradable poly-(D,L-lactide-co-glycolide) nanocapsules: factorial design and characterization

Local anesthetics are able to induce pain relief since they bind to the sodium channel of excitable membranes, blocking the influx of sodium ions and the propagation of the nervous impulse. Benzocaine (BZC) is a local anesthetic that presents limited application in topical formulations due to its low water-solubility. This study aimed to develop polymeric nanocapsules as a drug delivery system for the local anesthetic benzocaine (BZC). To do so, BZC loaded poly(D,L-lactide-co-glycolide) (PLGA) nanocapsules were prepared using the nanoprecipitation method and were characterized. The factorial experimental design was used to study the influence of four different independent variables oil response to nanocapsules drug loading. The physical characteristics of PLGA nanocapsules were evaluated by analyzing the particle size, the polydispersion index and the zeta potential, using a particle size analyzer. The results of the optimized formulation showed a size distribution with a polydispersity index of 0.12. an average diameter of 123 nm, zeta potential of -33.6 mV and a drug loading of more than 69%. The release profiles showed a significant difference in the release behavior for the pure drug in solution when compared with that containing benzocaine loaded PLGA nanocapsules. Thus, the prepared nonocapsules described here may be of clinical importance in both the processes of stabilization and delivery of benzocaine for pain treatment. (c) 2009 Elsevier B.V. All rights reserved.

Liposomal encapsulation improves the duration of soft tissue anesthesia but does not induce pulpal anesthesia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clinical significance of supplementary innervation of the lower incisor teeth: a dissection study of the myelohyoid nerve

In view of the relevance of the mylohyoid nerve to clinical difficulties in achieving deep analgesia of the lower incisors, a dissection study was undertaken. Dissections from 29 adult cadavers of both sexes were studied with the aid of a dissecting microscope. The following observations were made: a supplementary branch of the mylohyoid nerve entered the mandible through accessory foramina in the lingual side of the mandibular symphysis in 50% of the cases; it generrally arose from the right side (76.9%) and entered the inferior retromental foramen (84.6%); the mylohyoid nerve branch either ended directly in the incisor teeth and the gingiva or joined the ipsilateral or contralateral incisive nerve. In view of this information concerning the high incidence of possible involvement of the mylohyoid nerve in mandibular sensory innervation, it is advisable to block it whenever intervention in the lower incisors is indicated. Routine mylohyoid injection is recommended after mental nerve block. If the inferior alveolar nerve is chosen for anesthetic purposes, additional mylohyoid injection should be given only if pain persists. The mylohyoid injection should be given at the inferior retromental foramen on the median aspect of the inferior border of the mandible through extraoral approach.

EFEITOS DA INFUSAO CONTINUA DO PROPOFOL SOBRE A FUNCAO RENAL DO CAO. ESTUDO COMPARATIVO COM O PENTOBARBITAL SODICO

Little research has been done with propofol in relation to renal function. The aim of this study was to evaluate the effects of the continuous infusion of propofol on renal function in dogs. Sixteen dogs, previously anesthetized with pentobarbital sodium (30 mg.kg-1) for surgical preparation, catheterism and monitoring, were studied. The dogs were mechanically ventilated with air and received alcuronium (0.2 mg.kg-1 in bolus and 0.06 mg.kg-1 - maintenance). The following parameters were studied: heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), aortic blood flow (A(o)BF - by electromagnetic flowmeter installed in the ascending aortic), aortic vascular resistance index (A(o)VRI), renal plasma flow (ERPF - by para-aminohipurate clearance), glomerular filtration rate (GFR - by creatinine clearance), effective renal blood flow (ERBF = ERPF/1 - hematocrit), urinary volume (UV), renal vascular resistance (RVR = MAP.80/ERBF.10-3), urinary sodium excretion (UE(Na)), fractionated sodium excretion (FE(Na)), osmolar clearance (C(osm)) and free water clearance (C(H2O)). These parameters were studied at 15 (M1), 30 (M2), 45 (M3) and 60 (M4) min after beginning pentobarbital sodium infusion (5 mg.kg-1.h-1). The dogs were allocated into two groups of eight animals each: G1 (control-pentobarbital sodium) and G2 (propofol). In G1, pentobarbital was given at the four times studied. G2 dogs received the same treatment as G1 dogs at M1 and M2; infusion of pentobarbital was substituted by propofol (3 mg.kg-1 bolus, followed by 12 mg.kg-1.h-1 continuous infusion) at M3 and M4. Profile Analysis was used to analyze the results statistically. In G1 (pentobarbital), there was a significant increase in RVR (M1 < M4) and a decrease in ERPF and ERBF (M1 > M4). In G2 (propofol) there was only a significant increase in A(o)BF (M1 < M2 = M3). In comparison among groups, these was a significant alteration of FE(Na) at M3 (pentobarbital > propofol). It was observed that the continuous infusion of propofol in dogs, at the given doses, did not alter the basic variables of renal function and hemodynamics studied. We concluded that propofol can be one of the drugs of choice to provide base anesthesia in studies of renal function in dogs.

ALGIAS CRANIOFACIAIS - UM ROTEIRO PARA O EXAME FISICO DIRIGIDO

Craniofacial pain is a frequent challenge for the physician anamnesis with the goal to obtain specific and useful information about symptoms in craniofacial pain. It can be improved by identifying aching points. In the article, the authors present a practical and specific schedule for physical examination to be applied in patients with chronic pain. This specific schedule, which has proved useful in detecting the exact anatomic sites of pain, has a sequence ordered which includes palpation and inspection of muscles, nerves and arteries.

SUFENTANIL INTRANASAL COME MEDICACAO PRE-ANESTESICA EM CRIANCAS

Background and objectives: Among the different routes used for the administration of preoperative medication, the intranasal route offers the advantage of a rapid systemic absorption as well as the avoidance of painful intramuscular and intravenous injections. The aim of the present study is to evaluate the efficacy of sufentanil as a preoperative medication for the reduction of anxiety in pediatric patients in addition to its effects on the children's behaviour during the induction of anesthesia. Methods - Thirty patients whose ages ranged from 1 to 9 years old, physical status ASA 1, submitted to elective surgeries participated in the study and received sufentanil (2 μg.kg-1) by the intranasal route as preoperative medication. Using the modified Doughty index, the anxiety level was evaluated at 3 moments: To upon arrival of the child with parents: T5 and T10, five and ten minutes after the administration of the drug respectively. Behaviour during the induction of anesthesia was also evaluated. Induction of anesthesia was performed thiopental or ketamine. Results - The level of anxiety was not lower ten minutes after the administration of sufentanil and no improvement in the quality of the anesthetic induction was observed. Conclusions - Intranasal sufentanil in the doses used in this study did not prove to be efficient in the reduction of the anxiety level nor did it improve the quality of the induction of anesthesia when the period between the drug administration and separation from the parents was only ten minutes.

Pituitary-adrenal activity and opioid release in ponies during thiopentone/halothane anaesthesia

The effect of thiopentone/halothane anaesthesia on the release of endogenous opioid, adrenocorticotrophin, arginine vasopressin, cortisol and catecholamine was investigated in ponies. The contribution made by halothane itself was studied by maintaining six ponies with a constant 12 per cent end tidal halothane concentration and five with a concentration ranging between 0.8 and 12 per cent. Cardiorespiratory depression was more prolonged in the ponies receiving a constant 1-2 per cent end tidal halothane concentration than in those which received less halothane. Plasma lactate concentration increased and haematocrit decreased during halothane anaesthesia. The concentrations of met-enkephalin, dynorphin and catecholamines did not change and those of β-endorphin, adrenocorticotrophin, arginine vasopressin and cortisol increased during halothane anaesthesia. Halothane appeared to be a major stimulus to pituitary adrenocortical activation because the adrenocortical secretion was proportional to the amount of halothane inhaled. β-endorphin increased proportionally more than adrenocorticotrophin and their plasma concentrations were not correlated, suggesting that they have independent secretion mechanisms.