Quantitative lung perfusion scan as a predictor of aerosol distribution heterogeneity and disease severity in children with cystic fibrosis.

Background: The assessment of lung ventilation by radionuclide imaging has proved useful for the optimization of aerosol therapy in children with cystic fibrosis. Further analysis of lung perfusion may provide additional information.

Methods: Quantitative analysis of regional lung aerosol distribution (Tc phytates) and perfusion (Tc macroaggregates) homogeneity was performed in 18 children with cystic fibrosis, using the third and fourth spatial moments (skew and Kurtosis) of count distribution.

Long-term effects of different humidification systems on endotracheal tube patency: evaluation by the acoustic reflection method.

Background: Accumulation of mucous secretions in an endotracheal tube (ETT) increases its resistance, and the amount of deposit may be affected by the quality of humidification and heating of the inspired gas.

Methods: The authors assessed the impact of two humidification systems, a heated humidifier (HH) and a hygroscopic-hydrophobic heat and moisture exchanger (HME), on the ETT patency in patients selected to require mechanical ventilation for more than 48 h. This comparison was performed over two consecutive periods and used the acoustic reflection method, which characterizes the amount and site of ETT obstruction and allows estimating ETT inner volume and resistance.

Prevention of endotracheal suctioning-induced alveolar derecruitment in acute lung injury.

We studied endotracheal suctioning-induced alveolar derecruitment and its prevention in nine patients with acute lung injury. Changes in end-expiratory lung volume measured by inductive plethysmography, positive end-expiratory pressure-induced alveolar recruitment assessed by pressure-volume curves, oxygen saturation, and respiratory mechanics were recorded. Suctioning was performed after disconnection from the ventilator, through the swivel adapter of the catheter mount, with a closed system, and with the two latter techniques while performing recruitment maneuvers during suctioning (40 cm H2O pressure-supported breaths).

Effect of the humidification device on the work of breathing during noninvasive ventilation.

Objective: Heat and moisture exchangers (HME) increase circuitry deadspace compared to heated humidifiers (HH). This study compared the effect of HH and HME during noninvasive ventilation (NIV) on arterial blood gases and patient's effort assessed by respiratory muscles pressure-time product and by work of breathing (WOB).

Design And Setting: Randomized cross-over study in a medical intensive care unit.