Facemask pressure-controlled ventilation in children: what is the pressure limit?

BACKGROUND: In this study, we sought to determine the level of inspiratory pressures allowing adequate and safe ventilation without any risk of gastric insufflation (GI) in children according to age. METHODS: One hundred children, aged 1 day to 16 years, ASA physical status I to II, scheduled for general anesthesia were studied prospectively. After induction of anesthesia, children's lungs were ventilated with pressure-controlled ventilation. The initial inspiratory pressure was 10 cm H(2)O and was increased by steps of 5 cm H(2)O, up to a maximum of 25 cm H(2)O. At each step, GI was detected by epigastric auscultation. The recorded data were age and weight. At each step, the inspiratory pressure, the respiratory rate, the expired tidal volume, the minute ventilation, and the occurrence of GI were also recorded. RESULTS: GI occurred in 78 children. GI occurred in 95% of children younger than 1 year, in 93% of children aged 1 to 5 years, and 56% of children older than 5 years (P = 0.001). The pressure threshold at which GI occurred increased with age: the younger the child, the lower the GI pressure threshold. Tidal volume increased with inspiratory pressure, but at >15 cm H(2)O, tidal volume did not change significantly. CONCLUSION: The inspiratory pressure threshold at which GI can occur depends on age. It is low in infants and increases with age. In most cases, proper ventilation without GI was obtained with an inspiratory pressure

Target-controlled inhalation induction with sevoflurane in children: a prospective pilot study.

BACKGROUND: Target-controlled inhalation induction (TCII) with sevoflurane is becoming possible with new anesthesia platforms. Although TCII has already been performed in adults, it remains to be evaluated in children. METHODS: In a prospective study, we compared TCII using the Felix AInOC anesthetic station (Taema, Anthony, France) to our standard protocol inhalation induction in children scheduled for elective surgery under general anesthesia. After preoxygenation, sevoflurane induction was performed in both groups without priming of the circuit. Sufentanil was administered after venous line placement. RESULTS: In the TCII group, no overdosage or underdosage was observed except in two children where TCII failed owing to high agitation, and the number of adjustments was lower compared with our standard protocol inhalation induction (1(1-2.5[0-5]) vs 6(5-6[4-10]) respectively). Moreover, the delay to obtain target end-tidal sevoflurane concentration was shorter in the TCII group (2(1.6-2.7[1.3-4]) min vs 3.4(2.5-3.8[2.3-6.5]) min respectively). No significant difference in the delay of loss of consciousness or in the conditions for intubation or laryngeal mask placement was observed between the groups. CONCLUSION: The Felix AInOC allows TCII to be performed satisfactorily in children. Manual inhalation induction induced a higher number of adjustments and overdosages.

Use of the intubating laryngeal mask airway in emergency pre-hospital difficult intubation.

AIM OF THE STUDY: While several techniques are used for the management of difficult intubation (DI) in planned conditions in the operating theatre, they are not always suitable or usable in pre-hospital emergencies. We decided to assess the intubating laryngeal mask airway (ILMA) after failure of tracheal intubation (TI) under direct laryngoscopy. MATERIAL AND METHODS: After emergency physicians of the mobile intensive care unit were trained (theory and training on manikin) in using the ILMA (Fastrach), prospective data were collected after each use from March 2002 to December 2005. Data included patient's age, clinical status, number of direct laryngoscopies before using ILMA, Cormack and Lehane grade, subjective and objective evaluation of ease of ILMA insertion and TI (analogue scale from 1 to 10, attempts required, failure rate). RESULTS: Over 46 months, the ILMA was used 45 times (24: cardio-respiratory arrest, 21: anaesthesia with rapid sequence induction). Median age was 59 years [range 20-86]. The number of direct laryngoscopy attempts was 3 [0-4] (76% Cormack 4). The success of ILMA insertion and TI were 96 and 91%, respectively. CONCLUSION: Emergency physicians were satisfied with using the ILMA. It allowed TI in 91% of cases of DI. The ILMA can be recommended to be included in the algorithm of DI in pre-hospital emergencies after initial training.

Risk factors for the occurrence of electroencephalogram abnormalities during induction of anesthesia with sevoflurane in nonepileptic patients.

BACKGROUND: The aim of this prospective study was to determine the risk factors of epileptiform discharge during induction with sevoflurane in healthy adult patients. METHODS: Forty adult patients with American Society of Anesthesiologists physical status I were randomly allocated to one of four groups. Group A: Patients breathed 8% sevoflurane in oxygen (8 l/min) via a prefilled circuit. End-tidal sevoflurane was maintained at 4%. Tracheal intubation was performed at the third minute after cisatracurium injection. Group B: The anesthesia protocol was similar, but a vital capacity technique was performed. Group C: Patients were anesthetized as in group A but were hyperventilated. Group D: Patients were anesthetized as in group A, but end-tidal sevoflurane was maintained at 2%. An electroencephalogram was recorded before and during induction up to 11 min after the start of induction. Statistical analysis was performed with Statview 5.0 (SAS Institute Inc., Cary, NC) for multivariate analysis. RESULTS: Twelve patients experienced epileptiform discharges. Risk factors were female sex (odds ratio, 12.60; 95% confidence interval, 1.46-135), delay to the occurrence of beta waves (odds ratio, 0.92; 95% confidence interval, 0.86-0.99), and end-tidal sevoflurane (odds ratio, 8.78; 95% confidence interval, 1.12-69). Epileptiform discharges were not associated with significant hemodynamic or Bispectral Index variations. CONCLUSION: Induction with sevoflurane may result in epileptiform electroencephalographic activity. Only electroencephalographic monitoring allows the diagnosis. Risk factors are mainly female sex, short delay to onset of anesthesia, and high alveolar sevoflurane concentration. Induction with high sevoflurane concentration is controversial mainly in women.

Clinical assessment of the laryngeal tube in pediatric anesthesia.

BACKGROUND: The aim of this study was to evaluate a new device for airway management in children: the laryngeal tube (LT). METHODS: The LT is available in sizes S0-S3 for pediatric anesthesia. This prospective open study included 70 children ASA 1. The local Ethics Committee approval and parental consent were collected. The primary criterion was the success rate for insertion and ventilation. Secondary criteria were additional maneuvers and incidents elicited from LT use. RESULTS: Seventy children were included: S0 = 5, S1 = 8, S2 = 36, and S3 = 21. Insertion was successful: at the first attempt in 78.6%, second in 17.1%, and third or more in 4.3%. In 12% of cases it was not possible to successfully insert the LT and proceed to adequate ventilation. Failures were explained by: inability to obtain satisfying ventilation (n = 4), hypoxemia (n = 1), gastric insufflation (n = 6), cough (n = 1), and laryngospasm or stridor (n = 2), some with the same child. Minimal additional maneuvers for adequate ventilation were necessary in 35% of cases (all groups), but <20% when considering only sizes 2 and 3. Moreover, after five cases, the anesthesiologists became more proficient at inserting the LT (respectively 73.3% failure before five cases vs 13% afterwards). Gastric insufflation occurred in eight cases (11.4%). Controlled ventilation was used in 30 children and peak inspiratory pressure was 19.2 +/- 4 cmH(2)O. CONCLUSIONS: The LT is not recommended for children <10 kg. Over 10 kg, it provides a clear airway in most children, with a low rate of minimal additional maneuvers for sizes 2 and 3. The failure rate also decreases with the operator's training.

[Acute laryngeal dyspnea]. / Dyspnée aiguë laryngée.

Laryngeal dyspnea is a life-threatening emergency situation. The diagnosis is clinical and made from the association of: inspiratory bradypnea, intercostal and sus-sternal inspiratory depression, with or without stridor. The aetiologies are most often laryngeal tumours or inflammatory oedema; incidence of epiglottitis has decreased due to vaccine against Haemophilus influenzae. Airway obstruction due to foreign body includes acute laryngeal dyspnea and reflex paroxysmal coughing without fever. Management of a laryngeal dyspnea depends on the aetiology and the severity of clinical symptoms. Medical treatment associates racemic epinephrine aerosol, steroids, and oxygenation. In the presence of severe dyspnea, intubation after anaesthetising the patient and positive pressure ventilation is required.

Conducta a seguir ante una intubación dificultosa no prevista

Una causa común de morbilidad y mortalidad atribuible a la anestesia es la intubación dificultosa o fallida. Si se identifica previamente a los pacientes en condiciones de riesgo, un anestesista con un equipo preparado puede estar presente para enfrentarse a este problema. Los anestesistas deben tener el conocimiento y entrenamiento en seleccionar racionalmente los métodos de manejo de la vía aérea y realizarlos rápidamente y secuencialmente como sea requerido. Se desarrollan las distintas técnicas que se deben considerar en esta situación.

A common cause of morbidity and mortality attributable to anaesthesia is difficult or failed intubation. If those patients in whom intubation proves difficult could be identified in advanced, it could be arranged that an anesthetist properly equipped could be present to deal with the problem. Anesthetists are advised to become knowledgeable and skillful in selected rational methods of airway management and institute them sequentially and rapidly as required. The techniques to consider in this situation are reviewed.