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.

["Difficult intubation" workshops : impact on knowledge and practices]. / Ateliers "intubation difficile": impact sur les connaissances et les pratiques.

OBJECTIVES: To evaluate the impact of difficult intubation workshops on airway management knowledge and daily medical practice in anaesthesiology. STUDY DESIGN: Prospective survey. METHODS: The participants to the workshops accredited by the French college of anaesthesiologists (Cfar) in 2003 were invited to answer to MCQ before, immediately and three months after the course. They also completed a questionnaire provided during the workshop and three months later, focusing on medical practice and their own organization in the area of difficult intubation before and after the workshop. RESULTS: One hundred seven participants responded to the immediate evaluation (MCQ and questionnaire) whereas 32 responded to the delayed evaluation performed three months later. A subjective scale was used to assess the level of knowledge in difficult intubation (0: lowest level, 10 highest level). The mean score for subjective knowledge considering difficult intubation was 4.7+/-2.3 before the course and 6.9+/-1.6 at 3 months (P<0.001). The mean scores attributed to MCQ were not different before and after the workshops. Participants expected complementary practical training (65%) and theoretical courses (40%). Delayed evaluation revealed that 25/32 participants had to deal with difficult intubation during their clinical practice after the workshop, but 3 cases (12%) could not be managed with success. Defects could be observed in terms of organization: no difficult airway trolley (22%), no predefined difficult airway algorithm (66%), and information: no written information given to the difficult airway patient (44%), and no information given to the difficult airway patient's home doctor (91%). DISCUSSION: These results showed that difficult intubation remains a real problem for anaesthesiologists. They also revealed differences between subjective and objective knowledge and pointed out defects in terms of organization and management which should be improved.

[Which anaesthesia for children undergoing MRI? An Internet survey in the French university hospitals]. / Quelle anesthésie pour les IRM en pédiatrie? Résultats d'une enquête par Internet dans les CHU de France.

OBJECTIVE: To investigate the procedures used by French anaesthesiologists in children undergoing MRI. METHODS: A questionnaire was sent by Internet to every university hospital in France. Information concerning the specialty of the doctor in charge of the child, the age of the children, premedication, airway control, the agents used, presence of a specific recovery room, length of hospitalization and number of children undergoing MRI was obtained. RESULTS: Out of the 28 hospitals contacted, one did not reply and two did not perform anaesthesia for MRI. In 80% of cases, paediatric anaesthesiologists were in charge of the children. Only one team applied an age limit and performed sedation only in children over 10 kg. Specific monitoring for MRI was used by all teams. Premedication was given in 52% of cases. Parents were present during induction in 52% of cases. Sevoflurane was used in 52%, propofol in 40% and propofol with sufentanil in 8%. Presence of a venous line is systematic in 92% of cases. Intubation is systematic in 36% of cases, laryngeal mask in 20%, one or the other in 24%, and face mask and/or oral canula in 20%. The most widely used ventilation mode is spontaneous breathing (52%). All children go to the recovery room, which was close to the MRI unit in only 48% of cases and was less than 1 hour away in 72%. In 83% of cases, MRI is performed on a day-case basis and the number of procedures varies from 4 to 30 per week. CONCLUSION: While there is no standard anaesthetic protocol in France for children undergoing MRI, only specialist teams undertake such procedures.

Pressure-controlled ventilation is superior to volume-controlled ventilation with a laryngeal mask airway in children.

BACKGROUND: This prospective, randomized, crossover study had two purposes: first, to determine whether pressure-controlled ventilation (PCV) is safer than volume-controlled ventilation (VCV) by preventing gastric insufflation in children ventilated through an laryngeal mask airway (LMA); second, to assess whether the measurement of LMA leak pressure (P(leak)) is useful for preventing leakage during positive pressure ventilation (PPV). METHODS: Forty-one, 2 to 15-year-old children underwent general anesthesia with an LMA. The expiratory valve was set at 30 cmH(2)O and P(leak) was measured using constant gas flow. Children were randomly ventilated using PCV or VCV for 5 min in order to reach a P(ET)CO(2) not exceeding 45 mm Hg, and then they were ventilated with the alternative mode. If the target P(ET)CO(2) could not be obtained in one mode, we switched to the other. If both modes failed, children were intubated. Tidal volumes, P(ET)CO(2) and airway pressures were noted and compared between modes. Gastric insufflation was checked by epigastric auscultation. RESULTS: PCV provided more efficient ventilation than VCV, as targeted P(ET)CO(2) was obtained without gastric insufflation using PCV in all cases except one, whereas VCV failed in three cases. No gastric insufflation occurred when ventilating below peak. CONCLUSIONS: These findings suggest that in the age group studied, PCV is more efficient than VCV for controlled ventilation with a laryngeal mask. Gastric insufflation did not occur with this mode.

Pressure support ventilation during fibreoptic intubation under propofol anaesthesia.

GOAL OF THE STUDY: To assess the benefit of pressure support ventilation during fibreoptic intubation performed under propofol anaesthesia in patients having an anticipated difficult intubation. PROCEDURES: Thirty-two patients with ENT cancer, and having at least two criteria for anticipated difficult intubation were prospectively included. All patients received topical lidocaine 2% and propofol by plasma target control infusion (initial target concentration 3 microg ml(-1), then adjusted to maintain loss of consciousness without apnoea). They were randomly assigned between two groups: spontaneous breathing (SB) or pressure support ventilation (with a support level set at 10 cm H(2)O) both using Fi(o(2))=1. Conditions for fibreoptic intubation, respiratory parameters (pulse oxymetry, ventilatory frequency, tidal volume and PetCO2 after intubation) and haemodynamic parameters were recorded. RESULTS: Patient characteristic data and intubation conditions were similar between both groups. All patients had a successful fibreoptic intubation and none needed a rescue procedure because of desaturation. In spite of a longer duration of intubation, PE'CO2 after intubation was lower and tidal volume during intubation was higher with pressure support ventilation than in SB patients [38.1 (4.2) vs 42.3 (4.7) mm Hg and 371 (139) vs 165 (98) ml, respectively]. Desaturation episodes were observed in two SB patients conversely to no episode during pressure support ventilation, probably because of the higher minute ventilation. CONCLUSION: Pressure support represents a useful method to improve ventilation during fibreoptic intubation under propofol anaesthesia in patients with an anticipated difficult intubation.

[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.

[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.

Concentration of remifentanil needed for tracheal intubation with sevoflurane at 1 MAC in adult patients.

BACKGROUND AND OBJECTIVE: Inhalation induction with sevoflurane provides acceptable conditions for tracheal intubation. Opioids significantly decrease the alveolar concentration needed to achieve tracheal intubation. The purpose of this study was to determine the target concentration of remifentanil providing excellent conditions for tracheal intubation with sevoflurane at 1 minimum alveolar concentration without muscle relaxant. METHODS: Twenty-four consecutive patients, aged 18-50 yr, ASA I or II, were studied. Induction of anaesthesia was performed with sevoflurane at age-adjusted minimum alveolar concentration. Remifentanil was simultaneously administered using target-controlled infusion with the Minto model. Target plasma concentration of remifentanil was selected for each patient according to an up-and-down method. RESULTS: The mean target concentration of remifentanil for successful tracheal intubation was 3.3 ng mL(-1) (95% confidence interval: 2.6-3.9 ng mL(-1)). Arterial pressure, heart rate and bispectral index did not increase after tracheal intubation in the group of patients with successful intubation. CONCLUSIONS: Remifentanil at 3.3 ng mL(-1) together with sevoflurane at 1 minimum alveolar concentration provides excellent conditions for tracheal intubation in 50% of patients.

Pressure support ventilation during inhalational induction with sevoflurane and remifentanil in adults.

BACKGROUND AND OBJECTIVE: The purpose of this prospective randomized study was to assess the value of pressure support ventilation during inhalational induction with sevoflurane in adult patients. METHODS: Thirty-five adult patients, ASA I-II and scheduled for ear nose throat surgery were studied. Vital capacity induction with 8% sevoflurane in 8 L min-1 oxygen was performed. Pressure support ventilation was used in Group 1 with pressure set at 15 cmH2O. In Group 2, patients breathed spontaneously. After 2 min, sevoflurane was set to 3% and remifentanil 1 microg kg(-1) was injected over 2 min followed by an infusion of 0.1 microg kg(-1) min(-1). Two minutes after the end of the bolus, intubation was performed. Bispectral index, oxygen saturation, respiratory rate, end-tidal carbon dioxide, expired tidal volume and expired sevoflurane concentration were recorded every minute. RESULTS: Eighteen patients were included in Group 1 and 17 in Group 2. Saturation, respiratory rate and end-tidal carbon dioxide were similar in the two groups. Expired tidal volume was significantly higher and bispectral index values significantly lower in Group 1. Intubating conditions were better in Group 1. CONCLUSIONS: Pressure support ventilation provides both better ventilation and deeper level of anaesthesia during inhalation induction with sevoflurane.

Comparison of the anaesthetic requirement with target-controlled infusion of propofol to insert the laryngeal tube vs. the laryngeal mask.

BACKGROUND AND OBJECTIVE: The target effect-site concentration of propofol to insert a laryngeal mask airway was recently reported as almost 5 microg mL(-1). The present study aimed to determine the target effect-site concentration with target-controlled infusion of propofol to place classical larnygeal mask airway or current laryngeal tube in adult patients. METHODS: We included 40 patients scheduled for short gynaecological and radiological procedures under general anaesthesia in a randomized, double-blind manner using the Dixon's up-and-down statistical method. Monitoring included standard cardiorespiratory monitors, and bispectral index monitoring was used for all patients. Anaesthesia was conducted with a target-controlled infusion system: Diprifusor. The initial target plasma concentration of propofol was 5 microg mL(-1), and was changed stepwise by 0.5 microg mL(-1) increments according to Dixon's up-and-down method. Criteria for acceptable insertion were: Muzi's score < or = 2, and mean arterial blood pressure, heart rate or bispectral index variation <20% the baseline values. RESULTS: Target effect-site concentration of propofol required to insert laryngeal tube was 6.3 +/- 0.3 microg mL(-1) with Dixon method and ED50 was 6.1 microg mL(-1) (5.9-6.4) with logistic regression method. In the case of larnygeal mask airway they were 7.3 +/- 0.2 microg mL(-1) (Dixon method) and 7.3 microg mL(-1) (7.1-7.5; with logistic regression) respectively (P < 0.05). ED95 (logistic regression) was 6.8 microg mL(-1) (5.9-7.6) for laryngeal tube and 7.7 microg mL(-1) (7.3-8.0) for larnygeal mask airway (P < 0.05). Haemodynamic incidents were 55% in the larnygeal mask airway group vs. 30% in the laryngeal tube group (P < 0.05). CONCLUSIONS: The target effect-site concentration of propofol for insertion of laryngeal tube was lower than for larnygeal mask airway (P < 0.05), with a consequent reduction of the propofol induced haemodynamic side-effects.

[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.

[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.

[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.