Noncontact holmium:YAG laser thermal keratoplasty for hyperopia.

Purpose: To describe our experience with noncontact holmium:YAG laser thermal keratoplasty (Ho:YAG LTK).

Setting: Refractive Surgery and Cornea Department, Clinica de Ojos Dr. Nano, Buenos Aires, Argentina.

Excimer laser photorefractive keratectomy in pediatric patients.

Purpose: To evaluate the results of excimer laser photorefractive keratectomy (PRK) for myopia in pediatric eyes with amblyopia resulting from anisometropia.

Setting: Clinica de Ojos Dr. Nano, Buenos Aires, Argentina.

Entrainment of respiratory rhythm by periodic lung inflation: effect of airflow rate and duration.

In anesthesized, paralyzed, and mechanically ventilated rabbits, the rate and duration of airflow were varied to investigate the effect on the central respiratory rhythm during 1:1 entrainment (1 phrenic nerve burst for 1 pump inflation). Our results showed that 1) the largest range of 1:1 entrainment was obtained with the longest inflation durations associated with the lowest flow rates and 2) both inspiratory (TI) and expiratory (TE) durations (as estimated by the period of phrenic nerve activity and phrenic nerve silence, respectively) increased when total respiratory duration (TT = TI+TE) increased. The phase relationships we studied were DI (the time elapsing between the onset of phrenic activity and the beginning of pump inflation) and DE (the time between the end of phrenic activity and the end of pump inflation).

Volume detection during voluntary and passive breathing.

The ability to detect small changes in tidal volume (VT) during either volitional or passive breathing was compared in seven normal subjects. Passive breathing was achieved with positive pressure applied at the mouth by a ventilator. Although baseline breathing pattern was similar for each subject during the two types of breathing, the ability of the subjects to detect changes in VT was at least as good, and in general better, during passive as compared to volitional breathing.

Entrainment of the respiratory rhythm by periodic lung inflation during vagal cooling.

The aim of this study was to determine whether pulmonary receptors other than slowly adapting stretch receptors are capable of entraining the respiratory rhythm when periodically stimulated during artificial ventilation. Experiments were performed on anaesthetised (urethane, 1.5 g/kg) and paralysed (pancuronium bromide, 0.