The growth of the nasal septum in the 6-9 week period of foetal development--Warfarin embryopathy offers a new insight into prenatal facial development

BACKGROUND

The aim of this study was to de the role of the nasal septum in embryonic facial development.

METHODS

Nasal septal growth and facial development were examined in sagittally-sectioned 6-9 week human foetuses and compared to previously published data for later prenatal periods. To complement this data a cephalometric study of a child with untreated warfarin embryopathy was undertaken since a previous study in rats had shown warfarin exposure interferes with septal growth.

RESULTS

The results showed that prenatal septal growth was maximal during the 6-9 week period and resulted in the establishment of a facial profile that was maintained until birth. This critical of growth corresponds to the period of warfarin exposure of the human foetus that results warfarin embryopathy. The cephalometric examination of a child with untreated warfarin embryopathy showed a combination of short anterior cranial base and a short maxilla had contributed to a significant retrusion of the maxilla suggestive of failure of the midface to devel the 6-9 week period.

CONCLUSION

These findings would support the hypothesis that the nasal septum plays an active role in embryonic midfacial development.

Airway pressure effects on the performance of the Ohmeda Universal Portable Anesthesia Complete vaporizer with push-over mechanical ventilation

In previous studies, the use of mechanical ventilation in a push-over configuration with the Ohmeda Universal Portable Anesthesia Complete vaporizer was evaluated by bench testing and clinical application. During the clinical evaluation, it was noted that airway pressure transmitted back through the vaporizer during inspiration affected performance based on the concentration of inhalation agent delivered. This study evaluated the effects of airway pressure on vaporizer performance and established concentration curves for clinically significant incremental increases in airway pressure. Vaporizer performance was consistent, predictable, and correlated with the data obtained in previous studies.

Performance of the universal portable anesthesia complete vaporizer with mechanical ventilation in both drawover and pushover configurations

Currently, a mechanical ventilator that can be adapted to the Universal Portable Anesthesia Complete (UPAC) vaporizer and anesthetic delivery system does not exist. The need for the anesthetist to concentrate on drug delivery and fluid resuscitation for the combat casualty in the field setting provides an expedient for the adaptation of a ventilator to the UPAC system. The purpose of this study was to determine whether the performance of the UPAC vaporizer was significantly altered when mechanical ventilation was provided in a drawover versus a pushover configuration, and to provide vaporizer performance curves for ventilatory parameters common for mechanical ventilation. The Ohio V5A and Lifecare PLV-100 ventilators were used in controlled benchwork analysis. The results of the comparison between the two ventilators indicated that there was no significant difference in vaporizer output between drawover and pushover configurations. The data indicated that vaporizer output could be reliably predicted in either mode and was correlated with tidal volume and respiratory rate.

Clinical evaluation of pushover mechanical ventilation with the Ohmeda Universal Portable Anesthesia Complete vaporizer

Previous studies have not demonstrated the usefulness of a mechanical ventilator with the Universal Portable Anesthesia Complete (UPAC) field anesthesia delivery system in a pushover mode. This study demonstrated that the Lifecare PLV-100 ventilator can function effectively in a practical pushover configuration with the UPAC vaporizer. By comparison, vaporizer output followed the patterns of documented concentration curves for isoflurane at a given dial setting and minute ventilation. Measured airway pressures in the breathing circuit were within physiological parameters.

Treatment planning for the mixed dentition malocclusion--treatment and goals

The mixed dentition stage of development may provide a useful window of opportunity to embark upon orthodontic therapy to correct an isolated malocclusion or provide preliminary treatment as a precursor to more comprehensive therapy at a later stage of the patient's physical development. As in all forms of orthodontic treatment, the planning of any correction must be carried out with care so that meaningless tooth movement can be avoided. Growth modification procedures can also be considered during this stage of development but, as this is connected intimately to increased height velocity, these procedures are most usefully carried out in the late mixed dentition, or more frequently in the early permanent dentition as this coincides more closely with peak height velocity. Several studies have suggested that approximately 20 per cent of patients presenting with a malocclusion can be treated appropriately during the mixed dentition. There would appear to be a genuine risk of falling off in cooperation levels in needed, permanent dentition treatment in many patients who have experienced one or more treatment procedures at an earlier stage in dental development. These findings reinforce the need for careful treatment planning during the mixed dentition.