[Intranasal midazolam in pediatric ophthalmology]. / Midazolam intranasal en ophtalmologie pédiatrique.

Intranasal midazolam was tested in pediatric patients undergoing ophthalmological examination. 15 children aged 3.5 months to 10 years received 0.35-0.5 mg.kg-1 intranasal midazolam in association with a corneal anesthesia. The onset of sedation was rapid and permitted adequate ocular examination in all cases. In 8 of 15 cases where surgery followed immediately, the induction of inhalational anesthesia was easier. No local or general adverse reaction was noted. This non-invasive method of anesthesia may be compared to the intrarectal administration of midazolam, but the rapid onset of sedation and a cleaner route seem more suitable in surgical environment.

Midazolam and flumazenil in ophthalmology.

Midazolam's pharmacodynamic properties are used in ophthalmology in several indications: 1. to relieve anxiety and unwanted reactions during radial keratotomy in ambulatory patients; 2. to provide sedation and amnesia during cataract surgery using local anaesthesia, in combination with low doses of phenoperidine; 3. to induce general anaesthesia, combined with fentanyl and vecuronium, for intraocular surgery in the elderly; and 4. to decrease intraocular pressure. Flumazenil is not in routine use but is usually administered to antagonise the deleterious effects of midazolam on upper airway resistances and the respiration system and may be used to reverse "paradoxical", i.e. anxiogenic reactions to benzodiazepines in the elderly.

Factors influencing pulmonary volumes and CO2 elimination during high-frequency jet ventilation.

An external spirometric method using a differential linear transformer was used to measure tidal volume (VT) and to determine factors influencing CO2 elimination and HFJV-induced "PEEP effect" in 15 critically ill patients under HFJV. VT increased with increasing driving pressure (DP) and decreasing frequency (f) and was influenced little by changes in I/E ratio. CO2 elimination, as reflected by the measurement of PaCO2, was mainly influenced by the absolute level of VT rather than by the product VT X frequency (PaCO2 = 5715/VT, r = 0.75, P less than 0.05). The primary phenomenon explaining HFJV-induced "PEEP effect" was intrapulmonary gas trapping due to incomplete exhalation of the first VT administered: the spontaneous relaxation times of these first VT were longer than expiratory time allotted to the ventilatory settings. HFJV-induced "PEEP effect" increased with I/E ratio, DP, and f and was markedly influenced by the mechanical properties of the total respiratory system. At given ventilatory settings, HFJV-induced "PEEP effect" was greater in patients with a normal or elevated time constant of the total respiratory system (tau RS) than in patients with a low tau RS. These results suggest that HFJV should not be used in patients with chronic obstructive pulmonary disease and asthma, and should be preferentially administered to patients having stiff lungs or decreased chest wall compliance.