Matt Maccallum

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We wanted to know whether the ventilatory response to low concentrations of CO2 is measurable in the absence of change in alveolar PCO2, is sleep state dependent, and is dictated by the resting respiratory pattern. Therefore, we gave 11 preterm infants (birth weight, 1,565 +/- 122 g; gestational age, 32 +/- 1 wk; postnatal age, 28 +/- 5 days) 0.5 to 1.5%(More)
In 10 preterm and 10 term infants, the effect of sleep state on chest distortion and on the ventilatory response to CO2 was assessed. It was found that chest distortion and ventilatory response to CO2 were independent of sleep state. Chest distortion, however, was more frequent in preterm than in term infants. The authors suggest that the increased(More)
To determine 1) the effect of arterial CO2 change on the neonatal cerebral circulation and 2) whether 100% O2 would produce significant decrease in cerebral blood flow (CBF), we studied 24 preterm infants to explain the late (5 min) hyperventilation observed in them during hyperoxia. Of these, 12 were studied before and during inhalation of 2-3% CO2 and 12(More)
The effect of sudden and sustained lung inflation on inspiratory time (Ti), expiratory time (Te) and duration of apnea, as a translation of the Hering-Breuer reflex, has not been systematically analyzed in preterm infants. To examine such effects, 10 infants (body weight 1,550 +/- 110 g; gestational age 31 +/- 1 weeks) were studied. Lung inflation was(More)
Differences in risk of decompression sickness (DCS) that have been observed among inert gases may reflect differences in gas solubility or diffusivity or both. A higher risk gas might generate a larger volume of evolved gas during decompression, thereby increasing the probability of DCS. If this hypothesis is correct, the composition of bubbles that develop(More)
Maintaining appropriate sedation and analgesia in pediatric burn patients can be quite challenging and often requires high doses of analgesics and anxiolytics because tolerance quickly develops. Escalating doses of opioids and benzodiazepines provide little additional benefit while increasing the incidence of side effects. Dexmedetomidine (DEX) is a novel(More)
Air vs. He-O2 (20.9% O2) recompression treatment was examined in a model of severe decompression sickness (DCS) using male albino guinea pigs (Cavia porcellus, 500-600 g). Following decompression to the surface from simulated air dives at 200 or 250 fsw, both anesthetized and unanesthetized animals often exhibited responses indicative of a fatal bout of DCS(More)
To examine the ventilatory response to 100% and 15% O2 during wakefulness and sleep, we studied eleven preterm infants birthweight 1770 +/- 102 g; gestational age 32 +/- 1 weeks; postnatal age 31 +/- 5 days) on two occasions each. Wakefulness (W) was present around feeding time and was defined by open eyes for more than 2 min plus presence of purposeful(More)
To examine the influence of feeding on the chemical control of breathing in neonates, we studied the ventilatory response to 3% CO2 in air in nine bottle fed (BOT) and eight breast fed (BR) term infants during feeding while the infants were alert. Control responses were obtained either before or after feeding, VE, respiratory frequency, tidal volume,(More)
We have previously reported that O2 in the breathing gas mixture contributed significantly to the risk of decompression sickness (DCS) in rats after rapid (less than 10 s) decompression to the surface from depth. The rate of O2 uptake was extremely fast (less than 1 min estimated for equilibrium after a pressure change) compared to much slower rates for He(More)