Biomedical subjects
A Montes
Publications and source records attributed to A Montes.
[Influence of anesthetic technique in postoperative analgesia in thoracic surgery].
OBJECTIVE: To compare the intensity of postoperative pain after thoracotomy with 2 anesthetic techniques: 1) thoracic epidural block with bupivacaine administered before surgery (combined anesthesia with isoflurane) and 2) conventional balanced anesthesia with isoflurane and endovenous fentanyl. PATIENTS AND METHODS: Thirty patients scheduled for thoracotomy by lateral incision (T5-T6) were randomly divided into 2 groups of 15. Group A received 8 ml of 0.5% bupivacaine with adrenalin 1:200.000 30 min before start of surgery while group B received 8 ml saline solution through an epidural catheter inserted to T4-T8. Combined anesthesia (4 ml 0.5% bupivacaine through an epidural catheter 150 min after the first dose and isoflurane in 100% oxygen) was used in group A. Group B received balanced anesthesia with endovenous fentanyl 2.5 micrograms/kg and isoflurane in 100% oxygen. The difference in pain intensity during postoperative recovery was assessed by way of the following variables: number of boluses administered by epidural patient-controlled analgesia (bupivacaine 0.0625% and fentanyl 6 micrograms/ml); score on a visual analog scale of 10 at baseline and at 1, 3, 7, 11, 19 and 43 hours after surgery; and need for additional analgesia (diclofenac) during the 43 hours of study. Arterial gases were measured during the preoperative period and at 1, 3, 7, 19 and 43 hours after surgery. RESULTS: No significant differences in pain intensity measured on the visual analog scale, by the number of boluses per patients or by need for additional analgesia were found between the 2 groups. The total number of boluses administered and additional analgesic requirements were greater in the group receiving bupivacaine, although the difference was not significant (p = 0.095 and p = 0.056, respectively). Nor were there significant differences in pH and PaCO2 levels for the 2 groups. CONCLUSIONS: Analgesic efficacy after thoracotomy was similar for our 2 groups receiving either combined anesthesia (epidural bupivacaine at 0.5% and isoflurane) or balanced anesthesia with isoflurane and endovenous fentanyl.
[Propofol: ED50 and ED90 induction doses in pediatric anesthesia].
OBJECTIVE: To study ED50 and ED90 induction doses of propofol in children. PATIENTS AND METHODS: Seventy-two children from 1 to 110 months of age and premedicated with pentobarbital 4 mg/kg participated in the study. Seven different doses of propofol (1.5, 2, 2.5, 3, 3.5, 4 and 4.5 mg/kg) were injected into the dorsal hand or foot vein in 30 seconds. We measured the response to application of the mask, corneal reflex and response to trapezius muscle compression 30 and 60 s after administration. A log-probit statistical analysis was used and complications were noted. RESULTS: The doses that produced 50% elimination of reflexes (ED50) or 90% elimination (ED90) in our patients were 1.74 and 3.95 mg/kg for response to mask; 2.47 and 4.26 mg/kg for elimination of corneal reflex; and 3.27 and 4.79 mg/kg for compression of trapezius. Frequency of pain upon injection was 74% and that of spontaneous movement was 12%. Apnea (breathing halted for longer than 20 s) occurred in 7% of our patients. We recorded no cases of broncho or laryngeal spasm, or skin rash. CONCLUSIONS: Induction with propofol is appropriate given the rarity of stimulant effects, but there is a high frequency of pain upon injection, limiting the usefulness of this drug for anesthetic induction in pediatrics. ED50 and ED90 varies depending on the stimulus assessed.
[Comparison between fentanyl and a fentanyl-bupivacaine combination using epidural PCA for postoperative analgesia after thoracotomy].
HYPOTHESIS: The association of opioids and local anesthetics for spinal analgesia appears to have a synergistic++ effect. OBJECTIVE: To compare the efficacy of fentanyl in comparison with combined fentanyl and bupivacaine at low concentrations in a thoracic epidural system of patient-controlled analgesia (PCA) following thoracotomy. PATIENTS AND METHODS: Twenty male patients scheduled for thoracotomy by postero-lateral (T5-T6) incision received analgesia after surgery through a thoracic (T4-T8) epidural catheter connected to a PCA pump (continuous infusion and boluses). They were randomly assigned to 2 groups as follows: group A (n = 10) received a baseline infusion of fentanyl 1 microgram/kg/h and bupivacaine 0.125% with boluses of 12.5 micrograms fentanyl and bupivacaine at 0.125%. The variables studied were: score on a visual analog scale (VAS) before treatment and at 12 and 24 h; the number of boluses administered through the PCA pump, forced vital capacity (FVC) and peak expiratory flow (PEF) before treatment and at 12 h. RESULTS: Analgesia was satisfactory in both groups, with no significant differences in VAS and number of boluses administered. Nor were there significant differences in lung function tests. One instance of respiratory depression was recorded in group A. CONCLUSIONS: The analgesic effect obtained with epidural fentanyl or fentanyl/bupivacaine is similar and adequate, and the association of fentanyl and bupivacaine can be considered safe.
[Endoscopic-histopathological correlation in gastric lymphoma diagnosis: the experience of an oncologic institute].
Among the Gastric Lymphoma' chief features are the varied endoscopic appearances and the difficulty for its conventional bioptic diagnosis. In order to focusing on this problem we analyzed 15 years of experience on this matter at the "Luis Razetti" Oncological Institute. 10 cases were morphologicaly classified as follow: a) Exophytic type 5/50%. The most difficult morphology for its endoscopic diagnosis was the infiltrative type, in its large gastric folds category 2/20%, yielding a 33% of bening diagnosis. Histopathologicaly a 66% of bening diagnosis was obtained and a 33% of uncertain diagnosis. The exophytic type in its erosive protruding mass category was the second most difficult morphology fot both endoscopic and histopathologic diagnosis. When the last two categories were associated with ulceration, the malignant diagnosis increased. 40 of the cases were operated on without preoperative histological diagnosis. All the cases were operated on without preoperative histological diagnosis. All the cases corresponded with Large cells diffuse type of Non Hodgkin's Lymphoma, a diagnosis reached in only one opportunity by endoscopic biopsy. No correlation between tumoral morphology and intraparietal growth was found. 3 patients survived for more than 1 years. It can be concluded that video endoscopic methods could help to improve the endoscopic knowledge in gastric lymphoma diagnosis, while polipectomy snare biopsy, dye methods like Indigo Carmin and special techniques like mucosectomy could help to improve the histologic diagnosis, because conventional biopsy provides small and superficial samples.
[Chemoprevention in cancer of the head and neck].
The world-wide incidence of cancer of the head and neck of 500,000 cases/year has remained unchanged in recent years in spite of anti-smoking campaigns. Moreover, long-term survivors of cancer of the head and neck or of other respiratory and digestive tumors have a constant annual 5-7% risk of developing a second primary tumor in the same area. Lately, prevention programs have added synthetic and natural products to prevention programs for the purpose of reversing the progression of premalignant lesions to invasive cancer or reducing the probability of developing cancer in high-risk individuals. These products are known as chemoprevention agents. In the case of tumors of the head and neck, it is known that leukoplasia and erythroplasia are epithelial lesions on which invasive tumors may develop. Recent studies have demonstrated that the use of retinoids can produce regression rates over 60%, thus reducing the risk of secondary neoplasms of the respiratory and digestive tract by 35-55%. The current status of chemoprevention in head and neck cancer and the use of retinoids as chemoprevention agents in this type of neoplasm are reviewed.