Optimal dose of sufentanil in children for intubation after sevoflurane induction without neuromuscular block.

BACKGROUND: We studied 63 ASA I children (age 2-8 yr) to determine the sufentanil dose needed to facilitate intubation under excellent conditions after inhalation induction with various end-tidal concentrations of sevoflurane without neuromuscular block. METHODS: Subjects were allocated randomly to receive sevoflurane end-tidal concentrations (e'(sevo)) of 2.5%, 3%, or 3.5%. Anaesthesia was induced with sevoflurane 6% without nitrous oxide for 2 min, and then inspired sevoflurane concentration was adjusted to keep e'(sevo) at 2.5%, 3%, or 3.5% according to the group. Subjects received i.v. sufentanil according to an 'up and down' design. Tracheal intubation by direct laryngoscopy was performed 6 min after sufentanil injection. Intubation was considered successful, if intubation conditions were excellent as determined by the laryngoscopist. RESULTS: The ED(50) [effective dose for 50% of subjects; mean (sd)] of sufentanil required for excellent intubation conditions was 0.6 (0.12), 0.32 (0.10), or 0.11 (0.07) microg kg(-1) for e'(sevo) of 2.5%, 3%, or 3.5%, respectively. Using logistic analysis, the 95% effective dose (ED(95)) of sufentanil was 1.02 [95% confidence intervals (CI) 0.31-1.74] microg kg(-1), 0.58 (95% CI 0.17-0.99) microg kg(-1), or 0.28 (95% CI 0.04-0.52) microg kg(-1) for e'(sevo) of 2.5%, 3%, or 3.5%, respectively. CONCLUSIONS: Excellent intubation conditions could be obtained in children after inhalation induction with low sevoflurane concentrations and adjuvant sufentanil.

The I-gel, a single-use supraglottic airway device with a non-inflatable cuff and an esophageal vent: an observational study in children.

BACKGROUND: The I-gel is a new single-use supraglottic airway device with a non-inflatable cuff. It is composed of a thermoplastic elastomer and a soft gel-like cuff that adapts to the hypopharyngeal anatomy. Like the LMA-ProSeal, it has an airway tube and a gastric drain tube. Little is known about its efficiency in pediatric anesthesia. METHODS: Fifty children above 30 kg, ASA I-II, undergoing a short-duration surgery were included in this prospective, observational study. We evaluated ease in inserting the I-gel, seal pressure, gastric leak, complications during insertion and removal, ease in inserting the gastric tube and ventilatory parameters during positive pressure ventilation. RESULTS: All devices were inserted at the first attempt. The mean seal pressure was 25 cmH(2)O. There was no gastric inflation and gastric tube insertion was achieved in all cases. The results appear similar to those in a previous study concerning laryngeal mask airway in terms of leak pressure and complication rates. CONCLUSION: Because the I-gel has a very good insertion success rate and very few complications, it seems to be an efficient and safe device for pediatric airway management.

A new single use supraglottic airway device with a noninflatable cuff and an esophageal vent: an observational study of the i-gel.

BACKGROUND: The i-gel is a new single-use supraglottic airway device with a noninflatable cuff and an esophageal vent. METHOD: In this prospective, observational study, we evaluated the i-gel in 71 women. RESULTS: Insertion success rate was 97%. Insertion was easy and performed at the first attempt in every patient. Mean seal pressure was 30 +/- 7 cm H(2)O, and average peak pressure was 11 +/- 3 cm H(2)O. The gastric tube was inserted in 100% of cases. Only one case of coughing and one mild sore throat occurred. CONCLUSION: The i-gel is a reliable, easily inserted airway device that provides an adequate seal with a low morbidity rate.

Intubation of infants with Pierre Robin syndrome: the use of the paraglossal approach combined with a gum-elastic bougie in six consecutive cases.

Infants with Pierre Robin syndrome are known to be difficult to intubate. We evaluated the paraglossal approach combined with a gum elastic bougie for intubation of these infants. Whilst under general anaesthesia, a conventional laryngoscopy was performed; if it failed to obtain a laryngoscopic grade I or II view, intubation was attempted using a paraglossal approach and a gum elastic bougie. Six consecutive infants were studied. Conventional laryngoscopy failed in all infants whilst the paraglossal approach combined with a gum elastic bougie was successful in five of the cases. The paraglossal approach combined with a gum elastic bougie made intubation easy in most children with severe Pierre Robin syndrome and difficult laryngoscopy. Therefore we recommend this as the first line for airway management in such children. However, a fibreoptic bronchoscope and an anaesthetist trained in fibreoptic intubation must still be present when dealing with severe Pierre Robin syndrome infants.

[Inhalation induction with sevoflurane in paediatrics: what is new?]. / Induction au masque facial avec le sévoflurane chez l'enfant: le point sur les nouvelles modalités.

The delay for loss of consciousness can be shortened by using high concentration sevoflurane > 6% and by adding N2O during inhalation induction with sevoflurane in paediatrics. Mean time for tracheal tube insertion is lower than 5 min in the majority of studies. This shorter delay is not associated with any significant increase in clinical side effects. However, recent studies have demonstrated the epileptogenic effect of high effect site sevoflurane concentration (occurrence of spike wave on the EEG). Inhalation induction with high alveolar sevoflurane concentration is questionable mainly when it is associated with hyperventilation. Positive pressure ventilation or pressure support ventilation make it possible to maintain normocapnia and to monitor FeSevo. Adding a narcotic decreases the target cerebral concentration required to perform tracheal intubation and consequently the risk of spike wave occurrence.

[Oropharyngeal ulcers following anaesthesia with the laryngeal tube S]. / Ulcérations oropharyngées suite à l'utilisation d'un tube laryngé S.

We report a case of acute tongue and uvula ulcerations consecutive to the use of a laryngeal tube Sonda (LTS) for airway management. The LTS was used during general anaesthesia for hysteroscopy and resection of endometrial hyperplasia. No trouble occurred during LTS insertion and anaesthesia. Symptomatic treatment provided complete resolution within a few days. This event points out the potential risk of more serious lesions.

[Clinical study of the laryngeal mask in paediatric. Comparison of the LMA-ProSeal and LMA-classic]. / Etude clinique du masque laryngé en pédiatrie. Comparaison du LMA-classic et du LMA-ProSeal taille 2 et 2,5.

OBJECTIVES: To compare the Classic laryngeal mask airway (MLC) and the ProSeal LMA (MLP), size 2 and 2.5 in terms of ease of insertion, leak pressure and side effects during insertion and extraction in the recovery room. STUDY TYPE: Randomised prospective. MATERIAL AND METHOD: All children between 10 and 30 kg scheduled for general anaesthesia with laryngeal mask (ML) were included. There was no imposed protocol for the anaesthesia. The ML size was determined according to the child's weight. The MLC was inserted using the standard technique. The MLP was inserted following the recommendations, with or without the handle according to the operator's choice. The data analysed were: insertion type, ease of insertion of the mask, of the nasogastric tube (SG), number of attempts of mask insertion, complications, gastric leaks. RESULTS: One hundred (and) twenty children were included. There was no statistical difference in terms of difficulty of insertion, number of failed attempts, leak pressure or side effects. The use of the handle did not make insertion easier. Insertion of a nasogastric tube was possible in 92% cases. CONCLUSION: MLP is as easy to use in children as the MLC. MLP has the advantage of allowing rapid access to the stomach. It seems that the MLP is safer since its correct position is confirmed by easy gastric tube insertion.

[Occurrence of epileptiform crisis in child under sevoflurane anaesthesia]. / Survenue d'une crise épileptiforme avec le sévoflurane chez un enfant.

A case report is presented of an unknown epileptic child, who developed convulsive movements during inhalation of 3.9% sevoflurane for 45 minutes associated with moderate hyperventilation. Epilepsy was discovered on the EEG, which was performed postoperatively.

[Induction of anaesthesia with target-controlled inhalation of sevoflurane in adults with the ZEUS anaesthesia machine]. / Induction par inhalation de sévoflurane à objectif de concentration chez l'adulte avec le respirateur ZEUS.

OBJECTIVES: To evaluate if the new anaesthesia platform ZEUS (Dräger Medical) allows the induction of anaesthesia with target-controlled inhalation of sevoflurane. STUDY DESIGN: Prospective clinical study. PATIENTS: Adult ASA I or II patients scheduled for elective surgery under general anaesthesia. METHODS: After preoxygenation during 3 min at 100% oxygen, patients were asked to breathe normally; the target end-tidal concentration of sevoflurane was fixed at 4% without priming of the circuit. Sufentanil (target concentration 0.5 ng/ml) was administered 40 s after. RESULTS: Ten patients (48+/-22 yrs) were included. Sevoflurane was detected in the circuit after 36+/-5 s; the target end-tidal concentration of sevoflurane was obtained at 130+/-19 s. Loss of consciousness was observed after 119+/-7 s. The induction was achieved in all patients without any incident. CONCLUSION: This new anaesthesia system make available the induction of anaesthesia with sevoflurane without priming of the circuit.

[Clinical evaluation of the single use Laryngeal Tube in adults: the LTD]. / Evaluation clinique chez l'adulte du tube laryngé à usage unique: le LTD.

OBJECTIVES: The Laryngeal Tube (LT) is a supra-laryngeal device indicated to manage upper airway during anaesthesia. Leak pressures were lately reported higher for the LT as compared to the LMA. A recent study found a small amount of proteinaceous material on LMA after classical sterilization suggesting a risk of contamination by unconventional transmissible agents (prions). The aim of this study was to evaluate the effectiveness of the single use Laryngeal Tube: the LTD. STUDY DESIGN: Prospective study realized after ethical committee agreement and patient consent for participation. PATIENTS AND METHODS: Adults, ASA score< or =3, 18 to 75-year-old, without upper airway abnormality or difficult intubation criteria, anaesthesia< or =2 h, free access to patient's head and LTD. The following criteria were evaluated: easiness of insertion, assisted (AV), controlled (CV) and spontaneous ventilation (SV); leak pressure (LP) 5 and 15 min after insertion; complications during anaesthesia conducted with propofol and remifentanil under bispectral index monitoring. RESULTS: 55 patients were included; only one failure was reported at insertion. AV and CV were easy, SV difficult in 4 patients with chin lift necessary for adequate ventilation. LP was 28.92+/-8.4 and 30.87+/-8.68 cmH2O 5 and 15 min after insertion respectively. No major incident was noticed throughout the study. CONCLUSION: the use of the LTD was easy and successful. Moreover the LTD totally excluded the risk of contamination by unconventional transmissible agents.

High frequency jet ventilation and upper tracheal stenosis: a model study.

A chest-lung model, consisting of a human laryngo-tracheo-bronchial tree cast (4 or 5 bronchial generations) tightly enclosed in a 100 l rigid box was used to assess the potential efficiency of high frequency jet ventilation in patients with upper tracheal stenosis. The elasticity of the air in the box stimulated normal adult chest-lung compliance. Diaphragms (0.5 or 1.5 cm thick) were inserted into the upper trachea to simulate stenoses of 0.7, 1, 1.5 and 1.75 cm inner diameter. A rigid injector-catheter (5 mm outside diameter) was directed in the axis of the trachea with its tip 2.5 cm beneath the stenosis. The end inspiratory alveolar pressure (PA), the end expiratory pressure (PEEP) and the tidal volume (VT) were measured at a rate of 100/min and 30% inspiratory to total periods ratio. Entrained flow, Vem, measured at the start of air insufflation, was compared to that calculated (Vec) from a simple model. For a given setting of the ventilator, PEEP, PA--PEEP and VT were approximately linearly related to the difference in diameters of stenosis and injector. While PEEP decreased, both PA--PEEP and VT increased with increasing diameter of stenosis. When the diameter of the stenosis was higher than 1.5 cm no changes in PA--PEEP and VT were observed, owing to the narrowest section of the larynx. Vec was always higher than Vem. The thickness of the stenosis did not affect the results, and the diameter of the stenosis appeared to be the main factor affecting the ventilatory parameters under our experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

[Guidelines on difficult intubation in anesthesia: evaluation of 2 information diffusion methods]. / Les recommandations dans l'intubation difficile en anesthésie: évaluation de deux modalités d'information.

BACKGROUND: In 1996, experts from the Société Française d'Anesthésie et de Réanimation published guidelines about difficult intubation. We aimed to assess the effectiveness of two diffusion methods of these guidelines, media versus direct mailing plus media diffusion, and the relation between reading of the guidelines and practice behavior and training willingness. METHODS: Data were collected in two different samples of 300 anesthetists from three regions for pre and post-intervention surveys (E1 and E2 samples). Half of the anesthetists from E2, randomly chosen, received a direct mailing of the guidelines (E2a sample). The remaining constituted the E2b sample. Three assessment criteria were used, two concerning practice behavior and one training willingness. Relationship between these criteria and diffusion methods and reading was tested using logistic regression. RESULTS: The response rates were respectively 91%, 80% and 78% in the E1, E2a and E2b samples. The socio-professional features were not statistically different between the three samples. There was no relationship between the criteria and the diffusion methods. The direct mailing did not increase the reading rate (81% and 82% respectively in the E2a and E2b samples). The rate of anesthetists who routinely screened for predictive signs of difficult intubation (one of the practice criteria) was higher in E2a than in E2b (28% and 12% respectively). In the multivariate analysis, the difference only appeared among the sub-group of anesthetists who did not receive the direct mailing. The private practice was associated with a lower rate of routine screening. CONCLUSION: No impact of the diffusion methods on practice behavior and training willingness was found. Reading was inconstantly associated with practice behavior.

[Inhalation induction]. / Induction par inhalation.

OBJECTIVES: To clarify how pharmacokinetics explains the speed and quality of mask induction with sevoflurane alone or associated with adjuvants. To describe the various techniques to obtain adequate anaesthesia for laryngeal mask or tracheal tube insertion. To give the indications, contra-indications and complications of this technique. DATA SOURCES: Data were obtained from Medline and authors clinical experience. DATA SYNTHESIS: Inhalation induction in adults affords rapid loss of consciousness similar to the intravenous route if high concentrations of sevoflurane are delivered to the patient. Time of laryngeal mask or tracheal tube insertion is longer but may be reduced by adding N(2)O and/or a low opioid dose. The interest of benzodiazepine as premedication is not established but is highly probable when considering its potentiating effect on halogenated agents. Without any adjuvant, inhalation induction maintains spontaneous ventilation better than propofol. This justifies favouring this technique when difficult intubation is anticipated. This technique is associated to less or similar cardiovascular effects than intravenous propofol. However, some patients exhibit dramatic tachycardia and arterial pressure increase that should lead to caution in cardiovascular disabled patients. This sympathetic hyperactivity occurs with epileptiform EEG activity that was never associated with postanaesthesia mental dysfunction. In aged or cardiac patients, by reducing sevoflurane concentrations from 8% to 2% (or by 2% decreasing steps), the cardiovascular effect of this inhalation induction is better than propofol. This technique is contra-indicated in HMS susceptible patients and those suffering from a myopathy, or patients with intracranial hypertension, a full stomach or active gastro-oesophageal reflux. CONCLUSION: Inhalation induction in adults remains little used in common clinical practice. Technical improvement by adding opioids and education of anesthetists should increase the diffusion of this alternative method to intravenous induction of anaesthesia.

[High frequency jet ventilation in paediatric anaesthesia]. / Utilisation de la jet ventilation en pédiatrie.

High frequency jet ventilation (HFJV) is an alternative ventilatory mode during anaesthesia for laryngeal microsurgery. This procedure ensures good visualization of the operating field but is not without risk. Thus, its use in paediatric patients requires sound knowledge of respiratory physiology of children and infants. In children up to 8 years, the jet ventilator adjustments must take into account the lower pulmonary compliance and the higher airway resistance (time-constant). In order to avoid barotrauma, which is the main HFJV complication, the jet ventilator has to include a monitoring airway pressure system. The driving pressure and the frequency must be gradually increased while checking thoracic expansion. Total intravenous anaesthesia with profound muscular relaxation using a thin transglottic catheter is the most commonly used technique. Standard monitoring of anaesthesia does not preclude strict clinical supervision so as to detect any pulmonary distension. The air-oxygen mixture must be adjusted to provide the lowest FIO2 possible (< or = 30%) when using the CO2 laser. The main indications for the use of HFJV in paediatric laryngeal microsurgery are laryngomalcia, laryngeal papillomatosis and subglottic haemangioma. HFJV is a reliable and useful technique in airway paediatric surgery providing the operator has good knowledge of the physiological particularities in children.

[Fastrach laryngeal mask and difficult intubation]. / Masque laryngé-Fastrach et intubation difficile.

OBJECTIVE: To evaluate the success rate of intubation through the intubating laryngeal mask airway (LMA-Fastrach) in patients with predictive signs of difficult airway or after intubation failure. STUDY DESIGN: Open prospective study. PATIENTS: The study included 33 adults, 21 with predictive signs of difficult airway and 12 after intubation failure. METHODS: After induction of anaesthesia, the intubating LMA was inserted. Proper insertion was confirmed by easy bag ventilation and capnography. Intubation through the intubating LMA was then carried out with an armoured endotracheal tube. If intubation failed, a second attempt was carried out after a gentle manipulation of the intubating LMA. After two attempts, if intubation remained impossible, fibrescopic intubation through the intubating LMA was carried out. In case of failure the usual tracheal intubation algorithms were used. RESULTS: Tracheal intubation through the intubating LMA was successful in all patients, in 32 on the first attempt and in one on the second. Successful tracheal intubation was possible on the first attempt in 25 patients (76%), on the second in four (12%) and after fibrescopic intubation through the intubating LMA in the four remaining (12%). CONCLUSION: The results of this study confirm that tracheal intubation through the intubating LMA can be recommended in patients with a difficult airway, whether foreseen or not.

[Anesthesia induction with sevoflurane in adult patients with predictive signs of difficult intubation]. / Induction anesthésique avec le sévoflurane chez le patient adulte avec des signes prédictifs d'une intubation difficile.

OBJECTIVE: This work was carried out to study induction with sevoflurane in adult patients with predictive signs of difficult intubation. STUDY DESIGN: Randomised prospective study. PATIENTS AND METHODS: The study had two parts. Part I: 15 patients without predictive signs of difficult intubation but with a cervical collar. Eight patients were anaesthetised with propofol 3 mg.kg-1 and fentanyl 2 micrograms.kg-1, seven with sevoflurane 8%. Part II: 20 patients with predictive signs of difficult intubation anaesthetised with sevoflurane 8%. RESULTS: In part I, all patients were intubated, the time for intubation was longer with sevoflurane, 6 vs 4 min. They were apneic only in the propofol group. After intubation, 7 cases of coughing (4 severe) occurred in the propofol group and 3 moderate coughing in the sevoflurane group. In part II, one patient experienced considerable agitation after oral airway insertion and was excluded. Other patients were intubated with sevoflurane. Seven patients were intubated with a bougie, three patients through an intubating LMA and one patient with a rigid bronchoscope. The other patients were intubated with a Macintosh blade. The mean time for intubation was 10 +/- 7 min and end tidal sevoflurane concentration after intubation was 4 +/- 0.6%. After intubation, 7 cases of coughing (3 severe) occurred but no desaturation < 95%. No significant haemodynamic variations occurred. CONCLUSION: Induction with sevoflurane 8% allowed tracheal intubation without major incidents. All patients breathed spontaneously. Sevoflurane can be recommended for induction in cases of predictive difficult intubation.

[Value of the monitoring of curarisation during prolonged mivacurium induced neuromuscular block]. / Intérêt du monitorage de la curarisation lors d'un bloc neuromusculaire prolongé par mivacurium.

A case of neuromuscular blockade of about 200 min of duration, in a 9-year-old boy from mivacurium 0.15 mg.kg-1 is reported. The diagnosis was delayed, after onset of the first signs of recovery, due to the lack of monitoring of neuromuscular transmission. The neuromuscular blockade was reversed with neostigmine 0.04 mg.kg-1. Complete reversal required fifty minutes. The presence of an abnormal genetic variant of pseudocholinesterases was demonstrated by the measurements of pseudocholinesterase activity and dibucaine number. The importance of monitoring of neuromuscular transmission for diagnosis and treatment of mivacurium-induced neuromuscular blockade is underlined.

[Procedures use by French anesthetists in cases of difficult intubation and the impact of a conference of experts]. / Procédures utilisées par les anesthésistes-réanimateurs français en cas d'intubation difficile et impact de la conférence d'experts.

OBJECTIVE: To analyse the management of difficult intubation (DI) by French anaesthetists and the impact of the French experts' conference (EC) on this topic. STUDY DESIGN: Prospective, comparative, before/after study by questionnaire carried out in Aquitaine, Provence-Alpes-Côte d'Azur and Alsace-Lorraine. MATERIAL AND METHODS: A questionnaire on demographical data, detection of DI, management techniques and desiderata for continuing education on DI, was sent three months before the publication of the EC to 100 randomly selected anaesthetists, in each region (group PRE). Three months after the diffusion of the EC, the questionnaire completed by a survey on the impact of the EC was sent to 100 other randomly selected anaesthetists in each region (group POST). In the latter group, anaesthetists who considered the EC were compared to those who did not. RESULTS: The participation rate was 91% for the group PRE and 79% for the group POST respectively. Both groups were not significantly different for age, gender, position and seniority. Most used techniques that included blind nasal intubation (84%), intubation through laryngeal mask (82%), and intubation with fibrescope (53%). Demands for additional training were for translaryngeal ventilation (68%), intubation with fibrescope (64%), retrograde intubation (52%), and intubation through a laryngeal mask (46%). The EC was known by 71% of anaesthetists. In this group, the EC improved the assessment rate of the three recommended predictive criteria for DI from 12 to 28% (P < 0.02), but neither the management policy, nor the desiderata for additional training. CONCLUSION: Currently, the search of predictive indicators for DI is not systematically applied. The EC has only slightly modified the practice patterns. The need for additional training is important.

[Normovolemic hemodilution in the treatment of sudden deafness]. / Apport de l'hémodilution normovolémique au traitement des surdités brusques.

After the apparition of a sudden deafness, 45 patients (22 men and 23 women, with a mean age of 44 +/- 14.9 years) were treated with normovolaemic haemodilution performed with dextran 60. They were placed into 4 groups depending on their hearing loss: total loss: 10 cases; severe loss: 90 to 70 db. 13 cases; moderates loss: 65 to 40 db, 14 cases, slight loss: less than or equal to 35 db, 8 cases. The mean time between the onset of the hearing loss and treatment was 9.3 +/- 12.4 days. The initial mean haematocrit was 44.8 +/- 3.8% and mean haematocrit after haemodilution was 33.1 +/- 2.8%. For 51% of the patients, an almost total recovery was obtained. In 15.5% of cases, recovery was between 25 to 50% of the hearing loss, and in 33.3% of the patients recovery was negligible. We did not find any relationship between hearing recovery and initial haematocrit. The best results were obtained in the group of patients treated early. Hearing gain was significatively better if delay in starting treatment was less than 7 days. There was a relationship between the initial hearing loss and the final recuperation. These results suggested that haemodilution increased labyrinth microcirculation and oxygenation of the cochlear sensory cells, reversing the ischaemic insult to these cells.

[Value of the association of normovolemic dilution and hyperbaric oxygenation in the treatment of sudden deafness. A retrospective study]. / Intérêt de l'association hémodilution normovolémique-oxygénothérapie hyperbare dans le traitement des surdités brusques à partir d'une étude rétrospective.

The multiple treatments of sudden deafness shows how this pathology still remains quite unknown. The authors present a retrospective study of 87 patients treated by normovolemic hemodilution associated to hyperbaric oxygenation. They obtain a total à 60% of significant recovery (ratio between hearing gain and initial hearing loss, above 25%) and in severe hearing loss (threshold between 70 and 90 dB) 60% of good results (ratio above 50%). The importance of the initial form of audiogram and the presence of dizziness as prognostic factors is not confirmed. On the other hand, the evolution of tinnitus is correlated with the deafness and it is a supplementary means to evaluate the therapeutic efficiency. Moreover the persistence of tinnitus represents an important after effect. Sudden deafness still remains a medical emergency and the delay for carrying out any treatment should be as short as possible. On the other hand it is possible to reduce hospital stay by two sessions of hyperbaric oxygenation per day.