Alejandro A. Nava-Ocampo

Is Chloral Hydrate/Hydroxyzine a Good Option for Paediatric Dental Outpatient Sedation?

The primary objective of this study was to evaluate in a random double-blind design, the sedative and behavioural responses of children undergoing outpatient paediatric dental procedures receiving either chloral hydrate (CH) alone or in combination with hydroxyzine. Forty American Society of Anaesthesiologists class I children (21 to 36 months of age) were randomly allocated to receive either 70 mg/kg CH alone or with 2 mg/kg hydroxyzine. The degree of crying, movement and overall behaviour was evaluated during treatment at different times. The combination of chloral hydrate/hydroxyzine (CH/H) significantly decreased crying and movement in relation to the effect induced by CH alone (p < 0.05) only at 45-60 min following the insertion of a rubber dam, whereas the overall behavior in both groups was no different throughout the dental procedures. In conclusion, our study demonstrated that hydroxyzine increased the effect of CH. However, because of the presence of high rates of oxygen desaturations and of deep sedation, careful use of this drug combination should be stressed.

Randomized trial comparing overnight preoperative fasting period Vs oral administration of apple juice at 06:00–06:30 am in pediatric orthopedic surgical patients

Background :u2002We aimed to evaluate the efficacy of clear liquids orally administered at 06:00–06:30u2003am on the morning of surgery to reduce prolonged preoperative fasting periods.

Caudal block with 4 mg·kg−1 (1.6 ml·kg−1) of bupivacaine 0.25% in children undergoing surgical correction of congenital pyloric stenosis

Background: Since 1970, bupivacaine 0.25% in a dose of 4u2003mg·kg−1 (1.6u2003ml·kg−1) has been used at the Hospital Infantil de México for caudal block in children undergoing surgical correction of congenital pyloric stenosis (CPS). Although this dose is considered unsafe, in our experience, it has been associated with a high success rate and a low incidence of adverse events. This experience has not been previously documented.

A theoretical approach to the mechanism of biological oxidation of organophosphorus pesticides.

Organophosphorus pesticides are the most common classes involved in poisonings related to pesticides. We used enzymatic activity of chloroperoxidase on the metabolism of some phosphorothioate pesticides published previously and molecular mechanics methods to perform a theoretical approach of the mechanism of biological oxidation of this class of pesticides. The molecular structure of eight pesticides were optimized by molecular mechanics methods using the CAChe program package for biomolecules, ver. 3.11 (Oxford Molecular Ltd., Campbell, CA). Total energy resulted from the structure optimization process and the partial charges of both phosphorus and sulfur were computed for every pesticide. Phosphorus partial charge and enzymatic activity were significantly related by linear regression analysis (r=0.82, P<0.05). Analyzing our results and using previously reported enzymatic activity of chloroperoxidase on these pesticides, we deduced chemical events involved in activation of the active site of chloroperoxidase and proposed a novel mechanism of oxidation for this class of pesticides. This mechanism will also help to understand the oxidation process of pesticides by cytochrome P450, and production of toxic metabolites.

Dose minimization study of single-dose epidural morphine in patients undergoing hip surgery under regional anesthesia with bupivacaine.

Background :u2002In order to decrease the rate of adverse effects, we aimed to identify the lowest analgesic dose of epidural morphine administered to patients undergoing hip surgery.

Simplified method to quantify furosemide in urine by high-performance liquid chromatography and ultraviolet detection

Simplified reversed-phase high-performance liquid chromatographic method with ultraviolet detection at 280 nm without extraction procedure is described to quantify furosemide in rabbit and human urine. An internal standard was not used. The lower limit of quantitation was 0.750 microg/ml using 50 microl urine samples (100 microl of total injection volume), and linear response was tested from 0.750 to 250 microg/ml in both humans and rabbits. Within and between-day accuracy and precision were always below 10% at all analyzed concentrations. Validation data showed that this method is linear, sensitive, selective, specific, accurate and reproducible.

A randomized trial of caudal block with bupivacaine 4 mg·kg−1 (1.8 ml·kg−1) plus morphine (150 μg·kg−1) vs general anaesthesia with fentanyl for cardiac surgery

Background: Regional anaesthesia has been used effectively in paediatric patients undergoing cardiac surgery and is thought to be safe.

Do structural properties explain the anticonvulsant activity of valproate metabolites? A QSAR analysis.

Summary: u2002Purpose: Differences in potency among valproate (VPA) metabolites could be explained by structural properties. Therefore, a quantitative structure–activity relation (QSAR) analysis was performed to study the relation between structural parameters and the effect of the following VPA metabolites: 4‐en‐VPA, 2‐en‐VPA, 3‐en‐VPA, 2,4‐dien‐VPA, 4,4‐dien‐VPA, 4‐hydroxy‐VPA, 3‐ceto‐VPA, 3‐hydroxy‐VPA, 5‐hydroxy‐VPA, and propylglutaric acid.

Preferences of Mexican anesthesiologists for vecuronium, rocuronium, or other neuromuscular blocking agents: a survey

BackgroundSeveral neuromuscular blocking (NMB) agents are available for clinical use in anesthesia. The present study was performed in order to identify preferences and behaviors of anesthesiologists for using vecuronium, rocuronium or other NMB agents in their clinical practice.Material and methodsThe cross-sectional survey was applied at the Updated Course of the Colegio Mexicano de Anestesiología performed last year. Of 989, 282 (28.5%) surveys were returned.ResultsMost anesthesiologists were working at both public and private hospitals, performed anesthetic procedures for hospitalized and ambulatory patients, and anesthetized children as well as adults. Respondents did not consider mechanomyography as the gold standard method for neuromuscular monitoring. The T25 was not recognized as a pharmacodynamic parameter that represents the clinical duration of the neuromuscular block. Most answered that vecuronium induces less histamine release than rocuronium, had never used any neuromuscular monitor, did not know the cost of vecuronium and rocuronium, and preferred rocuronium in multiple-sampling vials and vecuronium in either a vial for single or multiple sampling. Rocuronium was preferred for emergency surgery in patients with full stomach only. Almost all of anesthesiologists that conserve the unused drug did it without refrigeration and more than 30% conserve the unused drug in one syringe for further use.ConclusionVecuronium was preferred for most clinical situations, and the decision for this choice was not based on costs. Storage of unused drugs without refrigeration in a single syringe for purpose of future use in several patients represented a dangerous common practice.

Attitudes of Mexican anesthesiologists to indicate preoperative fasting periods: A cross-sectional survey

BackgroundIn Mexico, guidelines for fasting periods, or any audits on this topic are unavailable, and therefore the attitudes of anesthesiologists for recommending preoperative fasting periods are unknown.Material and methodsThe study was a cross-sectional survey of anesthesiologists subscribed to the Annual Updated Course, organized by the Sociedad Mexicana de Anestesiologia in 2000. The response rate was 31.4%.ResultsMost respondents were general anesthesiologists, with 5 or more years experience in a clinical post, were working in both public and private hospitals, and were performing anesthetic procedures on both pediatric and adult patients and in both ambulatory and hospitalized patients. Approximately 23% of the respondents considered natural fruit juices to be clear liquids. For a pediatric patient ingesting breast milk 1 h before undergoing a surgical procedure, 45% thought that surgery should be delayed for 3h, followed by those delaying the surgical procedure for 6 to 8 h. Our results show that more than 50% of the anesthesiologists had better defined attitudes for fasting milk and clear liquids in patients of 6 month or under than for older children and adults. However, due to the poor definition or pre-operative fasting, using clear liquids, in all other patient groups, several patients are allowed to go without oral clear liquids administration for prolonged periods.ConclusionPreoperative fasting periods recommended by Mexican anesthesiologists differ from international guidelines.