Comparative effects of laryngeal mask and tracheal tube on total respiratory resistance in anaesthetised patients.

We compared the effects of the laryngeal mask and tracheal tube on total respiratory resistance in 10 anaesthetised, mechanically ventilated patients undergoing otological microsurgery. The subjects were randomly divided into two groups. In the first group, the tracheal tube (Rüsch) was inserted for the first series of measurements. This was then replaced by a laryngeal mask (Intavent) and a second series of measurements was made during the first hour of operation. In the second group, the same protocol was applied with inverse order in the use of the devices. From the measurement of respiratory flow and pressure at the airway opening, total respiratory resistance was calculated by multiple linear regression. The data were corrected to eliminate the previously determined nonlinear resistance of the two devices. Arterial blood pressure, electrocardiogram, oxygen saturation and end-tidal carbon dioxide concentration were continuously monitored. With the laryngeal mask and the tracheal tube, mean (SE) minute ventilation was 9.4(0.9)l.min-1 and 8.1(0.9)l.min-1, respectively for end-tidal carbon dioxide concentrations between 3.6 and 4.1%. Although the glottic resistance was included in the measurement performed with the laryngeal mask but not with the tracheal tube, mean (SE) total respiratory resistance was not significantly different with the two devices (0.61(0.32) and 0.69(0.35) kPa.l-1.s, respectively). Leakage was avoided with the laryngeal mask because the insufflation pressure never exceeded 1.7 kPa except in one patient suffering from severe chronic obstructive pulmonary disease who had a total respiratory resistance of 1.45 kPa.l-1.s. During the first hour of the operation all respiratory variables remained stable irrespective of the device used.

[Hydroxy-methyl-glutaryl-coenzyme A lyase deficiency manifesting as Reye's syndrome in a 3-year-old girl]. / Déficit en hydroxy-méthylglutaryl-coenzyme A lyase révélé par un syndrome de Reye chez une fille de 3 ans.

The authors report on one case of 3-hydroxy-3-methylglutaryl-coenzyme A lyase (HMG-Co A lyase) deficiency in a 3 year-old girl, presenting as Reye's syndrome. Urinary organic profile suggested this inherited metabolic disease; decreased activity of HMG-Co A lyase was demonstrated in cultured fibroblasts. The metabolic etiologies of Reye's syndrome are summarized; clinical, biological, and therapeutic assessment of HMG Co A lyase deficiency are developed. The pattern of organic aciduria must be studied in all patients presenting with Reye's syndrome.

Evaluation of the multiple linear regression method to monitor respiratory mechanics in ventilated neonates and young children.

A potentially useful method to monitor respiratory mechanics in artificially ventilated patients consists of analyzing the relationship between tracheal pressure (P), lung volume (V), and gas flow (V) by multiple linear regression (MLR) using a suitable model. Contrary to other methods, it does not require any particular flow waveform and, therefore, may be used with any ventilator. This approach was evaluated in three neonates and seven young children admitted into an intensive care unit for respiratory disorders of various etiologies. P and V were measured and digitized at a sampling rate of 40 Hz for periods of 20-48 s. After correction of P for the non-linear resistance of the endotracheal tube, the data were first analyzed with the usual linear monoalveolar model: P = PO + E.V + R.V where E and R are total respiratory elastance and resistance, and PO is the static recoil pressure at end-expiration. A good fit of the model to the data was seen in five of ten children. PO, E, and R were reproducible within cycles, and consistent with the patient's age and condition; the data obtained with two ventilatory modes were highly correlated. In the five instances in which the simple model did not fit the data well, they were reanalyzed with more sophisticated models allowing for mechanical non-homogeneity or for non-linearity of R or E. While several models substantially improved the fit, physiologically meaningful results were only obtained when R was allowed to change with lung volume. We conclude that the MLR method is adequate to monitor respiratory mechanics, even when the usual model is inadequate.

Postaxial acrofacial dysostosis (Miller) syndrome: a new case.

We describe a new case of postaxial acrofacial dysostosis (Miller) syndrome. This syndrome consists of mandibulofacial dysostosis, similar to that seen in Treacher Collins syndrome, and postaxial limb deficiency. The mode of inheritance remains uncertain.

[Congenital tracheal stenosis due to complete circular rings. Tracheoplasty using autologous pericardium]. / Sténose trachéale congénitale par anneaux circulaires complets. Trachéoplastie à l'aide de péricarde autologue.

The case of a 9-month old infant with congenital tracheal stenosis due to complete tracheal rings, associated with an aberrant left pulmonary artery is reported. Surgery was carried out under extracorporeal circulation to ensure adequate oxygen supply. Extubation, thus made possible, enabled the lesion to located accurately by bronchoscopy. Tracheoplasty by means of an autologus pericardial patch was performed. The quality of the repair was checked by a second bronchoscopy. The long-term result is satisfactory.

[Cardiac failure complicating laryngomalacia in a newborn infant]. / Défaillance cardiaque compliquant une laryngomalacie chez un nouveau-né.

A case of cardiac failure with pulmonary hypertension in a neonate with laryngomalacia is described. The interest of clinical and echocardiographical follow up and transcutaneous blood gas measurements to monitor the course of any upper airway obstruction is emphasized.

[Mediterranean boutonneuse fever. Apropos of a fatal case in a newborn infant]. / Fièvre boutonneuse méditerranéenne. A propos d'un cas mortel chez un nouveau-né.

The authors report the case of a 20 day-old neonate who presented with boutonneuse fever. According to their knowledge, this is the first reported case occurring in a neonate. In this child, the infection seemed to be unusually severe with rapid evolution and encephalic signs.

[Methodology in the study of organic acids in children]. / Méthodologie d'étude des acides organiques chez l'enfant.

A method is described for the extraction of urinary organic acids in children, their conversion to TMS and oxime TMS derivatives and their separation by gas liquid chromatography on a packed column of 10% OV 101. The compounds are identified by mass spectrometry. Profiles of urinary organic acids in normal neonates and in several metabolic disorders are presented.