Bispectral index changes in carotid surgery.

BACKGROUND: Intraoperative monitoring of cerebral ischemia with shunting during carotid endarterectomy (CEA) remains controversial. Our objective was to evaluate the sensitivity and specificity of BIS changes during carotid clamping in relation to shunted patients in awake CEA. METHODS: Eighty CEAs under cervical block were included. There were two patient groups: with clinical signs of cerebral ischemia (shunted patients) and without signs of cerebral ischemia (nonshunted patients). Data were based on bispectral index (BIS) values and neurological monitoring at different surgery time points, with special attention paid during carotid clamping. BIS values were compared between shunted and nonshunted patients. Sensitivity and specificity, along with positive and negative predictive values of a percentage BIS value decrease during carotid clamping from baseline BIS values, were calculated in both patient groups. RESULTS: Shunting was performed in 11 patients with cerebral ischemia at carotid clamping. Mean BIS values were 82.82+/-11.98 in shunted patients and 92.31+/-5.42 in nonshunted patients at carotid clamping (p<0.001). Relative decreased BIS values in relation to basal BIS values were 13.57% in shunted patients and 3.68% in nonshunted patients (p<0.05). The percentage decrease in BIS was 14%, sensitivity was 81.8% (95% CI 49.9-96.8), and specificity was 89.7% (95% CI 79.3-95.4). CONCLUSION: BIS monitoring during carotid clamping is an easy, noninvasive method which correlates with cerebral ischemia in patients undergoing CEA. A decrease>or=14% from the basal BIS value presents a high negative predictive value, and ischemia is unlikely without a decrease. Nonetheless, a decrease may not always indicate cerebral ischemia with a low positive predictive value.

[Obstetric bleeding: an update]. / La hemorragia obstétrica. Actualización.

Massive bleeding in obstetrics still ranks among the most frequent causes of maternal morbidity and mortality worldwide. The most frequent type is primary postpartum hemorrhage, which is usually the result of an atonic uterus. The clinical priorities are to assure hemodynamic stability and to correct coagulation abnormalities. If pharmacologic treatment cannot achieve these goals, invasive methods such as interventional vascular radiology or artery ligation must be used. Hysterectomy is the last resort when the previous methods fail. For the best prognosis, in terms of preventing death, maintaining maternal fertility and minimizing morbidity, every maternity ward should have a well-defined multidisciplinary protocol that facilitates diagnosis and immediate treatment.

[Bolus administration of fentanyl vs continuous perfusion of remifentanil for control of hemodynamic response to laryngoscopy and orotracheal intubation: a randomized double-blind trial]. / Comparación de bolus de fentanilo con perfusión de remifentanilo en el control de la respuesta hemodinámica a la laringoscopia e intubación orotraqueal: estudio prospectivo, randomizado y doble ciego.

OBJECTIVES: To compare the efficacy and safety of fentanyl and remifentanil in the prevention of hemodynamic responses to direct laryngoscopy and orotracheal intubation, and to compare the effects of these techniques on peripheral blood oxyhemoglobin saturation in normotensive women undergoing scheduled gynecologic surgery. MATERIAL AND METHODS: Prospective clinical trial in ASA 1-2 patients undergoing gynecologic surgery. The patients were randomized to 2 groups: the remifentanil group received a perfusion of 1 microg x kg(-1) x min(-1) until intubation whereas the fentanyl group received a bolus dose of 2 microg x kg(-1). Etomidate (0.3 mg x kg(-1)) and rocuronium bromide (0.6 mg x kg(-1)) were used for anesthetic induction. Seven serial measurements of systolic, diastolic, and mean arterial pressure were recorded in addition to heart rate and peripheral blood oxyhemoglobin saturation at the following times: baseline, denitrogenation, postinduction, and 3 more times at consecutive 2-minute intervals. RESULTS: Fifty-four patients were enrolled. A statistically significant attenuation of the postintubation hemodynamic response was observed in the remifentanil group. The effect was evident on arterial pressure (P=.0001) and heart rate (P=.031) with respect to baseline values. That protective effect was not seen in the fentanyl group. No differences in peripheral blood oxyhemoglobin saturation were observed. CONCLUSIONS: Remifentanil provides greater hemodynamic control than fentanyl at the doses utilized. No adverse effects attributable to these opioids were observed in either group.

[Intracranial diffusion. A complication of retrobulbar anesthesia]. / Difusión intracraneal. Una complicación de la anestesia retrobulbar.

Retrobulbar anesthesia is considered a safe, effective local-regional technique for ocular surgery. However, local complications that can arise from needle trauma during injection, include retrobulbar hemorrhage, perforation of the ocular globe and occlusion of the artery and/or the central vein of the retina. Systemic complications, such as respiratory arrest, convulsions and cardiovascular collapse, have also been reported, and although they only occur in less than 1% of cases, they are potentially life threatening. We report two cases of intracranial diffusion after retrobulbar anesthesia and describe possible mechanisms that may contribute to its development.

[Propofol in continuous infusion for performing nuclear magnetic resonance in children: an effective alternative to sedation with other drugs]. / Propofol en infusión continua para la realización de resonancia nuclear magnética en niños: una alternativa eficaz a la sedación con otros fármacos.

Sedation is often needed for obtaining nuclear magnetic resonance (NMR) images in children. The aim of this study was to evaluate the efficacy of propofol administered by continuous infusion to non-intubated children for whom our hospital's usual method of sedation (oral chlorohydrate 75 mg/kg at a maximum dose of 2 g plus 4 hours sleep privation the night before) had failed. Deep sedation was induced in 37 ASA I-II children aged 4 and 14 year old, with 2.5 mg/kg propofol followed by 6 mg/kg/h in continuous infusion. An additional dose of 1 mg/kg was administered if the child moved, and the perfusion was reduced to 4 mg/kg if SpO2 fell below 95%. Apnea occurred after induction in 24% (n = 9), 29% (n = 11) required additional doses of propofol, and a tendency to hypercapnia was observed as the imaging procedure progressed. Sedation failed in one child, who required general anesthesia when opisthotonos presented after the induction dose. Awakening was early and satisfactory in all patients, with a score of 2 on the Ramsay scale 15 minutes after NMR. Deep sedation with propofol is a safe and effective method of performing NMR in a child for whom other methods of sedation have failed, provided the child is ASA I-II, monitoring is exhaustive and procedure is carried out by an anesthesiologist.

[Extrapulmonary tuberculosis in a patient with septic shock]. / Tuberculosis extrapulmonar en un paciente con shock séptico.

A 61-year-old woman who was negative for type 1 human immunodeficiency virus developed vertebral osteomyelitis and skin lesions due to sepsis by Staphylococcus aureus. Microscopic examination of the skin showed alcohol-resistant acid-fast bacilli. A polymerase chain reaction (PCR) assay for Mycobacterium tuberculosis was positive for skin and spinal samples, although the cultures were negative. The diagnosis of M. tuberculosis infection is difficult, particularly when the disease is extrapulmonary. Rapid diagnostic tests that use PCR identify the DNA of the bacillus with greater sensitivity than microscopic examination and can give results within 24 hours of receipt of a sample. We analyze the utility of PCR for diagnosing extrapulmonary tuberculosis.

[Monitoring of mechanical ventilation during IPPV: implications due to the intrapulmonary entrapment of gas. Study on a physical model of the lung]. / Monitorización de la mecánica ventilatoria durante IPPV: implicaciones debidas al atrapamiento intrapulmonar de gas. Estudio sobre modelo físico de pulmón.

This work was undertaken to determine the possible influence of gas trapping on the values of total respiratory system compliance and on the air flow resistance at the air ways obtained by conventional effects of positive telespiratory alveolar pressure (auto-PEEP) typical of gas trapping on ventilatory dynamics. This study has been carried out in a physical model of the lung. The results support the contention that in the above situation: 1) the total compliance of the respiratory system measured as the quotient between the current volume and the plateau pressure (C.DIN) shows lower values than those of the static compliance (C.EST), and 2) flow resistance at the air ways must be measured as the quotient between the time constant and the plateau pressure. It should not be measured as the quotient between the time constant and the static compliance since in that case the values would be lower than the real ones.

[Efficacy of 1% ropivacaine with and without hyaluronidase for peribulbar block]. / Eficacia de la ropivacaína al 1% con y sin hialuronidasa en el bloqueo peribulbar.

OBJECTIVE: To determine whether adding hyaluronidase to 1% ropivacaine without adrenalin enhances peribulbar anesthesia for cataract surgery with phacoemulsification. PATIENTS AND METHODS: Prospective double-blind study of 100 patients (ASA I-III) scheduled for outpatient cataract surgery with peribulbar blockade. The patients were randomized to two groups of 50 to receive either 10 mL of 1% ropivacaine without adrenalin and without hyaluronidase (Group R) or 1% ropivacaine without adrenalin but with 10 U/mL of hyaluronidase (Group RH). We compared the presence of complete akinesia, of adequacy of surgical conditions, and of the need for reinjection. For statistical analysis we used the chi-squared test and a Student t-test for independent samples, with statistical significance at 5%. RESULTS: A block adequate for surgery was obtained in 98% of the patients in Group RH and in 86.7% of the patients in Group R (p = 0.043). Reinjection was necessary for 28.6% of Group R patients and 8.9% of Group RH patients (p = 0.14). Complete akinesia was similar in the two groups. CONCLUSIONS: The greater efficacy of a peribulbar block with the addition of 10 U/mL of hyaluronidase to 1% ropivacaine without adrenalin, in comparison to 1% ropivacaine alone, was demonstrated by a lower rate of reinjection and ocular mobility, even though no statistically significant difference in either ocular or palpebral akinesia was found.

[Hypobaric metameric subarachnoid anaesthesia for anaesthetic management in vertebral reinforcement techniques. Our experience in 6 cases]. / Anestesia subaracnoidea hipobárica metamérica para las técnicas de refuerzo vertebral. Experiencia en 6 casos.

Vertebral reinforcement techniques, such as percutaneous vertebroplasty and kyphoplasty, are minimally invasive procedures used in the treatment of fractured or collapsed vertebras. The anaesthetic techniques employed during these procedures are diverse and with variable results. We report 6 cases, vertebroplasty and kyphoplasty using subarachnoid metameric anaesthesia with a hypobaric technique. Haemodynamic stability and analgesia were satisfactory in all of them.