A comparison of 0.5% ropivacaine and 1% mepivacaine for sciatic nerve block in the popliteal fossa.

BACKGROUND: The purpose of this study was to compare anesthetic efficacy and postoperative analgesia of 0.5% ropivacaine and 1% mepivacaine for sciatic nerve block in the popliteal fossa (popliteal block). METHODS: A prospective, double-blind study was carried out in 58 adult patients scheduled for outpatient foot or ankle surgery. They were randomized to receive popliteal block with 40 ml of either 0.5% ropivacaine (group R) or 1% mepivacaine (group M). An atraumatic, Teflon-coated needle connected to a neurostimulator was used to make a single puncture using a posterior approach. The times to onset of sensory and motor block, and the need for intraoperative sedation were recorded. Before discharge, patients were asked to document the time to first analgesic use, time to return of full sensation in the foot, and their evaluation of the technique. RESULTS: Onset time (mean+/-standard deviation, 95% confidence interval) of both sensory block (6.5+/-5.1 min, 4.47-8.49, in group R and 6.2+/-3.7 min, 4.83-7.69, in group M) and motor block (6.6+/-4.4 min, 4.81-8.23, in group R and 7.9+/-4.1 min, 6.29-9.53, in group M) was similar in both groups. Postoperative analgesia lasted longer in group R (15.2+/-5.1 h, 13.25-17.21) than in group M (5.7+/-1.8 h, 5.01-6.41; P<0.001). Duration of sensory block was longer in group R (20.7+/-6.2 h, 18.51-23.01) than in group M (6.5+/-1.7 h, 5.86-7.16; P<0.001). Acceptance of the anesthetic procedure was similar in both groups. CONCLUSION: In this study we demonstrated that both 0.5% ropivacaine and 1% mepivacaine for popliteal block produced rapid, effective and safe anesthesia but postoperative analgesia was more long-lasting with ropivacaine.

Acute cellulitis: an unusual manifestation of meningococcal disease.

We describe 2 patients who both developed cellulitis due to Neisseria meningitidis and review 8 other cases reported since 1966. Female patients outnumbered male patients by 8 to 2, and there were 5 children and 5 adults. Four cases were caused by the serogroup C meningococcus, 2 cases by serogroup B and 2 others by serogroup Y (the nature of the meningococcal group was not available in 2 cases). Diverse medical underlying conditions were present in 4 of the adult patients. The periorbital region (in all 5 children), limb (in 3 adults), neck (in 1 adult) and face and neck (in 1 adult) were the locations of the meningococcal cellulitis. In all 10 patients, a favorable clinical response to the antibiotic therapy was documented and no relapses occurred. These cases indicate that N. meningitidis should be considered as a causative agent of cellulitis in the appropriate clinical setting, particularly in children with signs of periorbital infection or adults with underlying diseases.

Perioperative management of glucose 6 phosphate dehydrogenase deficiency. A review of the literature.

Glucose 6 phosphate dehydrogenase (G6PDH) deficiency is the most frequent cause of hemolytic anemias due to enzyme abnormality. Perioperative management must be careful to avoid the onset of hemolytic crisis. We present a complete review of the literature on this illness and describe the perioperative management of an adult with known G6PD deficiency and the pathogenesis and clinical manifestations of the disorder and its possible anesthetic implications are discussed. A 49-year-old patient had undergone varum osteotomy in her left knee due to genu valgum. She had been diagnosed as having G6PDH deficiency sixteen years earlier provoked by ingesting beans. The perioperative circumstances capable of causing autohemolysis are described and discussed. In spite of the fact that the pattern is self-limited, it provokes the onset of jaundice and anemia which can complicate the recovery. Simple elimination of those elements which precipitate with oxyhemoglobin will allow an uneventful anesthetic procedure.

Anaesthetic implications of Cornelia de Lange syndrome.

Cornelia de Lange syndrome is a congenital disease characterized basically by psychomotor retardation associated with a series of malformations (mainly skeletal craniofacial deformities together with gastrointestinal and cardiac malformations). We present the case of a patient who underwent trauma surgery, discuss the anaesthetic problems involved and their relationship to the malformations that constitute this syndrome.

Trimethoprim/sulfamethoxazole and metabolic acidosis in HIV-infected patients.

OBJECTIVE: To describe a retrospective study of six HIV-positive individuals with compensated metabolic acidosis while receiving intravenous trimethoprim/sulfamethoxazole (TMP/SMX). CASE SUMMARY: Six HIV-infected patients were treated for Pneumocystis carinii pneumonia (PCP) with high-dose intravenous TMP/SMX. In spite of a favorable clinical and radiologic course, all six patients developed compensated metabolic acidosis 3-5 days after the start of treatment. This potential complication of TMP/SMX use was successfully managed with conservative treatment (cessation of therapy with or without additional administration of intravenous bicarbonate). DISCUSSION: TMP/SMX is first-line therapy for PCP in HIV-positive individuals, despite a high frequency of toxic effects in these patients. In addition to the cases reported here, only two other reports of metabolic acidosis secondary to TMP/SMX use in HIV-infected patients have been published in the literature. The precise mechanism of this untoward effect is not fully understood, although renal tubular acidosis induced by TMP/SMX could be implicated. CONCLUSIONS: TMP/SMX toxicity should be considered in the differential diagnosis of HIV-infected patients with acute metabolic acidosis. Metabolic acidosis can be expected to resolve shortly after discontinuation of the drug.

Milrinona a la salida de CEC: estudio preliminar / Milrinone at out of CEC: preliminar study

Describimos nuestra experiencia clínica con un inhibidor de la fosfodiesterasa plásmatica de tipo III (IPDE), la milrinona, como inotrópico a la salida de circulación extracorporea (CEC) en pacientes con mala función ventricular previa. Seleccionamos 10 pacientes, 8 varones y 2 mujeres, programados para cirugía extracorporea. Todos ellos tenían una fracción de eyección (FE) menor de 0.45, edades comprendidas entre los 50 y 80 años y se preveía unos tiempos de isquemia y de perfusión prolongados. Al desclampar la aorta se administró milrinona a una dosis de 50 mcg/Kg durante 15 minutos, seguido de una infusión a 0.375 mcg/Kg/min. Se recogieron diferentes parámetros hemodinámicos mediante presión arterial invasiva y catéter de arteria pulmonar en momentos fijos de la cirugía y el postoperatorio. La milrinona resulta útil al mejorar el gasto cardiaco y facilitar la salida de bomba de CEC en pacientes con mala función ventricular previa, si bien su uso conlleva requerimientos elevados de líquidos intravenosos y la asociación de una segunda droga vasoactiva.

[Hemodynamic and respiratory changes during lung transplant]. / Alteraciones hemodinámicas y ventilatorias durante el trasplante pulmonar.

OBJECTIVE: To study the hemodynamic and gasometric changes observed during lung transplantation, and discuss the differences between unilateral (ULT) and sequential bilateral lung transplantation (SBLT). PATIENTS AND METHODS: We enrolled 13 consecutive patients (8 ULT and 5 SBLT). Gasometric and hemodynamic readings, including right ventricular (RV) function measured as ejection fraction through a catheter, were recorded at the different phases of surgery. ANOVA and Neumann Keuls tests were used for statistical analysis. RESULTS: During ULT no significant changes in RV function were seen and gasometric alterations stayed within clinically tolerable limits. No significant hemodynamic or gasometric changes were observed during the first implantation during SBLT, although there was a significant increase in pulmonary artery pressure as cardiac index decreased, as well as significant depression of RV function and hypoxemia during reperfusion and ventilation of the first lung transplanted. Extracorporeal circulation was needed in one case. CONCLUSIONS: During SBLT, selective reperfusion and ventilation of the first transplanted lung is a moment of great hemodynamic and ventilatory instability. Exhaustive monitoring of RV function is essential for adequate management.

[Postoperative cognitive dysfunction]. / Disfunción cognitiva postoperatoria.

Although postoperative behavioral anomalies were first reported more than one hundred years ago, only in the past ten years has the profile for postoperative cognitive dysfunction (POCD) been defined. POCD is reversible and it has been suggested that the disorder has implications for increased mortality and morbidity if it is not diagnosed and treated early. At present the clinical presentation of POCD is thought to be variable and fluctuating, ranging from slight disorientation to coma. POCD can develop soon after surgery or appear several days later and its incidence is unknown as a result of the methodological difficulties involved in studying this entity. Of the various etiological factors that have been named, many can be modified during the period surrounding surgery. Once symptoms have developed,whether in the recovery unit or later, it is important to eliminate organic factors and begin treating the cause. The most important drugs for treatment are neuroleptics and benzodiazepines. We review the definition, epidemiology, etiology, pathophysiology and treatment of POCD and include a list of diseases and drugs associated with its development, as well as a description of psychological tests used for diagnosis.

Pseudoaneurysm of the femoral artery following percutaneous puncture and cannulation for invasive monitoring.

The risk of damage to the femoral artery after its cannulation is low; it coincides with a series of risk factors that include the use of relatively large-diameter introductor sheaths. We present a case in which pseudoaneurysm of the femoral artery developed after the introduction of a 16-gauge catheter (Abbocath, Abbott Laboratories, Chicago, Illinois, USA) into this vessel for the invasive monitoring of the arterial pressure in a patient who was admitted to the Postsurgical Intensive Care Unit during the postoperative course because of hemodynamic instability secondary to septic shock. We also discuss the prophylactic and therapeutic measures that can prevent or alleviate, respectively, that complication.

Modulation of constitutive and inducible hepatic cytochrome(s) P-450 by interferon beta in mice.

AIMS/METHODS: Interferon beta is used as a therapeutic agent, but its effects on the hepatic cytochrome P-450-dependent drug metabolizing system have not yet been characterized. We investigated the effect of interferon beta on cytochrome P-450 in mice. RESULTS: Interferon beta (2 x 10(5) units/mouse) significantly reduced total hepatic cytochrome P-450 (20%) and the activity of NADPH cytochrome C reductase (12%) 24 h after administration; lower doses had no such effect. Various monooxygenase activities were slightly reduced, the one most affected being 7-ethoxycoumarin O-deethylase (29%). In phenobarbital-treated mice, interferon beta reduced the induction of total cytochrome P-450 (22%), the activities of pentoxyresorufin O-dealkylase (38%), benzyloxyresorufin O-dealkylase (30%), erythromycin N-demethylase (30%), 7-ethoxycoumarin O-deethylase (16%) and cytochrome P-450 2B1 (33%) and 3A (45%) proteins. In beta-naphthoflavone-treated mice, interferon beta lowered the induction of total cytochrome P-450 (18%), the activities of ethoxyresorufin O-deethylase (31%) and of 7-ethoxycoumarin O-deethylase (25%) and of cytochrome P-450 1A1 protein (31%). CONCLUSIONS: Thus it appears that induced cytochrome(s) P-450 were susceptible to interferon beta, this effect not being influenced by the type of inducer. Since various members of the same cytochrome P-450 subfamilies catalyze oxidation of drugs in humans, our findings have potential significance as regards the fate of drugs or exogenous compounds given to patients receiving interferon beta.