High-frequency jet ventilation using a helium-oxygen mixture.

The physiological basis for the use of helium relates to the relationship described by Poiseuille. During turbulent gas flow, the factors determining the resistance to flow include the density of gas as well as the length and the radius of a tube. While it may not be possible to readily change the latter two, altering the density of the gas is possible by using helium instead of nitrogen. A helium-oxygen combination has been used most commonly to improve air exchange in patients with upper airway obstruction. Anecdotal reports also suggest the beneficial effects of helium during mechanical ventilation in patients with status asthmaticus, hyaline membrane disease, and other pulmonary parenchymal disorders. To date, the clinical reports have utilized helium only with conventional mechanical ventilation. We present a child whose progressive respiratory failure was treated by using high-frequency jet ventilation with a combination of helium and oxygen. The techniques for the delivery of helium and oxygen through the jet ventilator are discussed.

Transcutaneous measurement of carbon dioxide tension during long-distance transport of neonates receiving mechanical ventilation.

OBJECTIVE: To determine the efficacy of transcutaneous carbon dioxide tension measurement during high-risk neonatal transport. STUDY DESIGN: This was a prospective, randomized comparative study. Infants transported from hospitals more than 30 miles away from our center and who required respiratory intervention were enrolled. Alternating transports used a transcutaneous CO2/O2 monitor. Ventilation parameters and end transport blood gas values served as primary endpoints for the study. RESULTS: Infants with transcutaneous carbon dioxide tension monitoring were more likely to have decreased ventilator peak pressures during transport than neonates not monitored (-1.5 cm H2O vs + 0.6 cm H2O; p = 0.04). Monitored neonates were more likely to arrive at the tertiary center with a more normal pH and a CO2 tension between 35 and 45 mm Hg (4.7 to 6.0 kPa) than nonmonitored infants (p = 0.03 and p = 0.01, respectively). The stabilization times before transport were not significantly prolonged by the use of the transcutaneous monitor. CONCLUSIONS: Transcutaneous monitoring of CO2 tension improves short-term respiratory outcome in neonates receiving mechanical ventilation during transport.