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Biomedical subjects

J J Eledjam

Publications and source records attributed to J J Eledjam.

At least 37 records · Page 2Linked to original sources

Ophthalmic regional anesthesia: medial canthus episcleral (sub-tenon) anesthesia is more efficient than peribulbar anesthesia: A double-blind randomized study.

BACKGROUND: Regional anesthesia and especially peribulbar anesthesia commonly is used for cataract surgery. Failure rates and need for reinjection remains high, however, with peribulbar anesthesia. Single-injection high-volume medial canthus episcleral (sub-Tenon's) anesthesia has proven to be an efficient and safe alternative to peribulbar anesthesia. METHODS: The authors, in a blind study, compared the effectiveness of both techniques in 66 patients randomly assigned to episcleral anesthesia or single-injection peribulbar anesthesia. Motor blockade (akinesia) was used as the main index of anesthesia effectiveness. It was assessed using an 18-point scale (0-3 for each of the four directions of the gaze, lid opening, and lid closing, the total being from 0 = normal mobility to 18 = no movement at all). This score was compared between the groups 1, 5, 10, and 15 min after injection and at the end of the surgical procedures. Time to onset of the blockade also was compared between the two groups, as was the incidence of incomplete blockade with a need for supplemental injection and the satisfaction of the surgeon, patient, and anesthesiologist. RESULTS: Episcleral anesthesia provided a quicker onset of anesthesia, a better akinesia score, and a lower rate of incomplete blockade necessitating reinjection (0 vs. 39%; P < 0.0001) than peribulbar anesthesia. Even after supplemental injection, peribulbar anesthesia had a lower akinesia score than did episcleral anesthesia. Peribulbar anesthesia began to wear off during surgery, whereas episcleral anesthesia did not. CONCLUSION: Medial canthus single-injection episcleral anesthesia is a suitable alternative to peribulbar anesthesia. It provides better akinesia, with a quicker onset and more constancy in effectiveness.

Aged↗

Insertion time of the pulmonary artery catheter in critically ill patients.

OBJECTIVES: Measurement of the time elapsed from the decision to use a pulmonary artery catheter to the onset of the adapted treatment. DESIGN: Prospective study. SETTING: Critical care unit of a university hospital. PATIENTS: A total of 104 critically ill patients. INTERVENTIONS: The time elapsed from the decision to use a pulmonary artery catheter to the onset of the adapted treatment. Five time intervals (availability, preparation, catheterization, data collection, and therapeutic intervals) were individualized according to the times of decision of pulmonary artery catheter insertion, operator's hand washing, venipuncture, postoperative dressing, data collection, and the effective onset of subsequent therapy. MEASUREMENTS AND MAIN RESULTS: Among 120 used pulmonary artery catheters, seven could not be inserted. The time to use the pulmonary artery catheter was never shorter than 45 mins (median value = 120 mins). For availability, preparation, catheterization, data collection, and therapeutic intervals, the median values were 30, 20, 20, 20, and 10 mins, respectively. The availability and data collection intervals were shortened during the night period and the fourth quarter of the study, respectively. CONCLUSIONS: The pulmonary artery catheter use is time consuming. However, the availability and data collection intervals could be shortened.

Adult↗

Increased risk of unintentional dural puncture in night-time obstetric epidural anesthesia.

PURPOSE: To evaluate the experience of the operator and the time of epidural anesthesia as factors contributing to unintentional dural puncture (UDP). METHODS: In a prospective analysis of recorded cases of UDP the following variables were recorded: maternal height, weight, and weight gain, type of personnel providing epidural analgesia, number of attempts, and hour of the epidural procedure. Work time was divided into day-time (8 AM to 7 PM) and night-time (7 PM to 8 AM), according to the change of coverage of the delivery suite. Night-time was divided into first (7 PM to midnight) and second parts (midnight to 8 AM). Relative risk was used to compare the incidence of UDP among different work-times. RESULTS: A total of 1489 consecutive epidural procedures were considered. The incidence of dural puncture was 0.8% (12 cases). The relative risk was higher for night-time than day-time (risk ratio 6.33; 95% confidence interval, 1.39 to 28.80; P = 0.006). Seven cases were caused by three operators with poor expertise, and five by two skilled obstetric anesthesiologists. CONCLUSION: Operator experience and hour of procedure appear to be two important risk factors of UDP The increased risk of UDP in night-work could result from human factors such as fatigue, sleep deprivation or interruption.

Adult↗

Intravenous nicardipine for severe hypertension in pre-eclampsia--effects of an acute treatment on mother and foetus.

OBJECTIVES: To assess the efficacy in lowering blood pressure, and the safety for mother and foetus of an acute nicardipine therapy in severe pre-eclampsia. DESIGN: Prospective clinical study. SETTING: One university hospital obstetric unit. PATIENTS: Twenty consecutive adult pre-eclamptic patients with severe hypertension. INTERVENTION: Nicardipine, 1 microgram/kg per min, was given intravenously to lower the mean arterial pressure (MAP) by at least 15%. Then, the dosage was reduced by 1/3, and the final dosage was determined to maintain MAP at 20-30% below the initial value, by increasing or decreasing the infusion rate by 0.5 mg/h. MEASUREMENTS AND RESULTS: Maternal MAP and heart rate (HR) were assessed every 5 min for 1 h. Foetal HR (FHR) was recorded throughout the study period and assessed for Fischer score. Gestational age, Apgar scores, birth weight, capillary filling time and the duration of stay in the paediatric intensive care unit (ICU) were used to evaluate the short-term perinatal outcome. A 15-30% decrease in MAP occurred within 15-20 min in all patients. An increase in HR was noted, and two patients had severe tachycardia. Maternal side effects included flushing, headache, nausea and dizziness. FHR showed a transient decrease in acceleration episodes and occurrence of decelerations. No nicardipine-related foetal distress occurred. Four infants born during the study period did well at birth and had a good outcome. CONCLUSIONS: Acute nicardipine therapy can induce severe maternal tachycardia. No severe foetal or neonatal adverse effects occurred. This dose scheme requires comparison with alternative therapeutic options.

Acute Disease↗

[Propacetamol: from basic action to clinical utilization].

OBJECTIVE: To review pharmacology and therapeutic use of propacetamol, an injectable prodrug of acetaminophen (paracetamol). DATA SOURCES: Extraction from the Medline database of French and English articles on pharmacology and clinical use of propacetamol. STUDY SELECTION: Articles providing new data into the mechanisms of the analgesic action of paracetamol. Selection of controlled studies (original articles and abstracts of oral communications on therapeutic trials with propacetamol as a single agent or part of balanced analgesia protocols). Case reports and letters to the editor were not considered in this analysis. DATA EXTRACTION: Clinical articles were selected for advantages and adverse effects of propacetamol. Articles dealing with mechanisms of action of propacetamol and paracetamol were selected for the more recent data, excluding those reporting outdated theories not confirmed or abandoned. DATA SYNTHESIS AND CONCLUSION: Mechanisms of action of paracetamol differ from those of NSAIDs, giving account of a low risk of adverse renal, gastrointestinal and haematological effects. Thanks to their high therapeutic index, prescription of propacetamol and paracetamol is quite simple and safe. Main indications of both drugs are painful conditions, especially but not exclusively in the postoperative period, not requiring opioids and also in combination with other analgesic drug and/or techniques (balanced or multimodal analgesia). Because of cost, IV propacetamol is changed for oral paracetamol as soon as possible.

Acetaminophen↗

Effects of halothane and enflurane on ventricular conduction, refractoriness, and wavelength: a concentration-response study in isolated hearts.

BACKGROUND: Effects of halothane and enflurane on ventricular conduction, anisotropy, duration and dispersion of refractory periods, and wavelengths were studied, and putative antiarrhythmic or arrhythmogenic properties on ventricles were discussed. METHODS: High-resolution epicardial mapping system was used to study the effects of 1, 3, and 5 vol% halothane and enflurane in 30 isolated rabbit hearts. Ten hearts were kept intact to study the effects on spontaneous sinus cycle length (RR interval), perfusion pressure, and the occurrence of spontaneous dysrhythmias. In 20 other hearts, a thin epicardial layer was obtained (frozen hearts) to study ventricular conduction velocity, ventricular effective refractory period (VERP in four sites) and wavelengths. RESULTS: Halothane induced a concentration-dependent lengthening of RR interval, whereas enflurane did not. Both agents slowed longitudinal and transverse ventricular conduction velocity with no anisotropic change. Ventricular effective refractory period was prolonged at 1 vol% and was shortened at higher concentrations, with no significant increase in dispersion. Ventricular longitudinal and transverse wavelengths decreased in a concentration-dependent manner. Although changes in wavelengths could express proarrhythmic effects of volatile anesthetics, no arrhythmia occurred in spontaneously beating hearts or in frozen hearts. CONCLUSIONS: The ventricular electrophysiologic effects of halothane and enflurane were slight, suggesting that both agents are unable per se to induce functional conduction block and therefore reentrant ventricular arrhythmias.

Anesthetics, Inhalation↗

Release kinetics of cardiac troponin I and cardiac troponin T in effluents from isolated perfused rabbit hearts after graded experimental myocardial contusion.

BACKGROUND: Few experimental studies report effects of direct contusion on cardiac enzyme release. Cardiac troponins I (cTnI) and T (cTnT) have been shown to be highly sensitive and specific markers of myocardial cell injury. This investigation was designed to determine and compare the acute effects of quantified magnitudes of blunt cardiac trauma upon release of cTnI and cTnT in comparison with creatine kinase (CK) and lactate dehydrogenase (LD). METHODS: In 24 rabbit hearts prepared on a standard Langendorff apparatus, myocardial contusion (MC) was produced by a single blow with a ball falling from a predefined height, delivered directly to the surface of the heart. Hearts were divided into control (n = 6) and various quantified impacts: 75 mJoules (mJ) (n = 6), 100 mJ (n = 6), 200 mJ (n = 6). Coronary effluent samples for cTnI, cTnT, CK, and LD were collected at baseline, immediately after MC and 5, 15, 30, 45, and 60 minutes after MC. At the end of experiment, histologic condition was evaluated. RESULTS: The anti-cTnI and cTnT MAbs used in the cTnI (Access) and cTnT (Elecsys) assays cross-react with cTnI and cTnT of the rabbit. The time-courses of cTnI, cTnT, CK, and LD were monophasic in form. After MC, all parameters rose significantly compared with baseline and with control group. The maximal release occurred immediately after MC. The area under the cTnI curve and the maximal cTnI concentration were linked to the contusion energy when increased at 200 mJ. Maximal concentrations and areas under cTnT, CK, LD time activity curve were not linked to the contusion energy level and showed no between-energy group differences. The correlation found between maximal cTnI and maximal cTnT concentrations was 0.70 (p = 0.0001). Histologic examination showed cellular disruption and after the more severe impact, the extent of pathologic changes was more extensive. CONCLUSION: After graded experimental MC, maximal cTnI concentration and area under cTnI curve increase with the power of impact kinetic energy. Levels of cTnI allow a much higher accuracy in detecting the extent of myocardial injury postMC in comparison with cTnT, CK, and LD in this experimental study. These results should be consistent with the more extensive cTnI release with more severe impact in patients with blunt chest trauma. Furthermore, because specificity and time-course of release, both cTnI and cTnT should have a role in the diagnosis and evaluation of such patients.

Animals↗

Dispersion-based reentry: mechanism of initiation of ventricular tachycardia in isolated rabbit hearts.

The aim of the study was to determine whether facilitation of reentry by potassium-channel openers is related to dispersion of refractoriness and/or modification of anisotropic properties of ventricular myocardium. The dispersion of ventricular effective refractory period (VERP), longitudinal and transverse ventricular conduction velocities (thetaL and thetaT, respectively), and wavelength [lambda = VERP x theta(L or T)] were studied in Langendorff-perfused left ventricular epicardium in 20 rabbits during infusion of incremental doses of levcromakalim or nicorandil. Dispersion of refractoriness was assessed using standard deviation of VERP mean (SD-VERP), dispersion index (DI; SD-VERP/mean VERP), and maximum dispersion (Dmax = VERPmax - VERPmin). Ventricular conduction velocities and anisotropic ratio were not modified, whatever the dose used. VERP and lambda were significantly shortened at high concentrations of levcromakalim and nicorandil. At these doses, SD-VERP, DI, and Dmax were increased significantly. Analysis of ventricular tachycardia induction, performed using a high-resolution ventricular mapping system, confirmed that heterogeneity and shortening of VERP were factors inducing functional conduction block. Our data suggest that, in rabbit left ventricular epicardium, functional conduction block facilitating the occurrence of reentry could be initiated by shortening and, especially, by dispersion of refractoriness during infusion of potassium-channel openers.

Animals↗

Management of reflex sympathetic dystrophy.

Reflex sympathetic dystrophy (RSD) is currently defined as CRPS type I (complex regional pain syndrome). Due to the lack of comprehensive understanding of underlying pathophysiological mechanisms, a wide variety of therapeutic approaches are proposed, all of them being of unpredictable and variable efficacy. This is also due to the lack of controlled studies and randomized therapeutic trials. Most of the so-called "efficient" treatments are in fact based on anecdotal case reports and/or uncontrolled studies with small number of cases. Sympathetic blocks and active physiotherapy are, for many authors, the cornerstones of the efficient management. The role of prevention must be strongly emphasized, focusing, if RSD occurs following surgery, on the importance of pre- and postoperative efficient analgesia.

Analgesia↗

Medial canthus episcleral (sub-Tenon) anesthesia imaging.

Medial canthus single injection periocular anesthesia is an alternative technique to classical regional anesthesia techniques for cataract surgery. The occurrence of a chemosis at the end of this injection has made us question ourselves about the real site of injection. The purpose of this anatomic study was to identify this site with precision, and to describe the spreading of the injected solution. Various volumes of colored liquid latex were injected when using this technique on 10 human orbits. They were deeply frozen and sectioned in thin slices. The site of injection is clearly the episceral (sub-Tenon) space. This is a gliding space through which pass the ciliary nerves supplying the globe sensitivity. This could explain the high quality of the analgesia of the globe. With the larger volumes injected, spreading of the latex was detected in the orbicularis palpebra. This probably explains the good akinesia of the lids obtained without any facial block. Spreading of the latex to the rectus muscles sheaths should explain the good akinesia of the globe, but was only partially proved in this study. We conclude that the medial canthus single injection periocular anesthesia is an episcleral (sub-Tenon) injection which may explain good anesthesia.

Anesthesia, Local↗

Training is required to improve the reliability of esophageal Doppler to measure cardiac output in critically ill patients.

OBJECTIVES: Assessment of and effect of training on reliability of esophageal Doppler (ED) versus thermodilution (TD) for cardiac output (CO) measurement. DESIGN: Prospective study. SETTING: Intensive care unit of a university hospital. PATIENTS: 64 consecutive critically ill patients requiring a pulmonary artery catheter, sedation, and mechanical ventilation. INTERVENTIONS: Esophageal Doppler CO measurements were performed by the same operator, whereas TD CO measurements were carried out by other independent operators. A training period involving the first 12 patients made the operator self-confident. In the remaining patients, the reliability of ED was assessed (evaluation period), using correlation coefficients and the Bland and Altman diagram. Between training and evaluation periods, correlation coefficients, biases, and limits of agreement were compared. MEASUREMENTS AND RESULTS: During training and evaluation periods, 107 and 320 CO measurements were performed in 11 out of 12 patients and in 49 out of 52 patients, respectively. Continuous CO monitoring was achieved in 6 out of 11 patients and in 38 out of 49 patients during training and evaluation periods, respectively. Between the two periods, correlation coefficients increased from 0.53 to 0.89 (p < 0.001), bias decreased from 1.2 to 0.1 l x min(-1) (p < 0.001), and limits of agreement decreased from 3.2 to 2.2 l x min(-1) (p < 0.001). CONCLUSION: A period of training involving no more than 12 patients is probably required to ensure reliability of CO measurement by ED.

Aged↗

[Pressure-controlled mechanical ventilation: a simplified titration method of the extrinsic positive expiratory pressure].

OBJECTIVES: Extrinsic positive end-expiratory pressure (PEEPe) may improve gas distribution within the lungs, induce alveolar recruitment or, conversely, produce pulmonary overdistension, and modify the respiratory impedance. Under pressure-controlled mechanical ventilation (PCV) this phenomenon modifies the minute ventilation and the dynamic compliance of the respiratory system (Crs,dyn). This study was aimed to assess the incidence of a significant gain in Crs,dyn under the effect of PEEPe during PCV. STUDY DESIGN: Prospective, open, descriptive, case series study. PATIENTS: Surgical intensive care unit patients, under sedation, neuromuscular blockade and PCV because of severe hypoxaemia (ARDS or acute lung injury). METHODS: Four incremental levels of PEEPe (4 to 16 cmH2O) of 30 minute duration were applied. Crs,dyn, and PaO2/FIO2 were recorded at the end of each level of PEEPe. The resulting gain in Crs,dyn was calculated and considered as significant if it was greater than the upper limit of confidence (at 99.8%) of the statistical distribution of all the recorded gains. RESULTS: Thirty patients were included, median and extreme values (within brackets) of PaO2/FIO2 of 117 [53-230] and Crs,dyn without PEEPe of 29 [14.3-46.8] mL.cmH2O-1. Among the 120 recorded gains, a gain in Crs,dyn was found significant at least once in 15 tests of PEEPe out of 30. Within the two groups of patients, the increase in PaO2/FIO2 with incremental PEEPe was similar. The levels of PEEPe producing the greatest increase in Crs,dyn were not correlated with the increase in PaO2/FIO2. CONCLUSION: In 50% of the studied patients a significant gain in Crs,dyn was found, allowing a less traumatic PCV. These results suggest the clinical usefulness of this method of titration of PEEPe, which requires neither specific devices nor a disconnection of the patient.

Adult↗

[Postoperative locoregional analgesia in the adult: epidural and peripheral techniques. Indications, adverse effects and monitoring].

Regional analgesia is a very effective way to treat postoperative pain. Lumbar and thoracic epidural analgesia are well adapted to major abdominal and thoracic surgery. Nevertheless, respiratory side effects induced by opioids are potentially severe and an adequate monitoring is essential. In orthopaedic surgery, perineural blocks are the best technique to manage postoperative pain and perineural catheters may be used. The importance of intra-articular analgesia, simple and safe, is not fully understood. The association of a local anaesthetic inducing a minor motor block and a strong sensitive block (bupivacaine, ropivacaine), with an opioid seems to be the best pharmacologic choice regarding quality of analgesia and safety. Benefits of postoperative regional analgesia on mortality and morbidity are not demonstrated. Medical and nursing staff and specialized units should improve quality of postoperative regional analgesia as well. General guidelines for the practice of regional anaesthesia must be closely followed.

Analgesia, Epidural↗