November 2008

Notes from the Section

• The fall issue of our Section Bulletin is online now, so click on the link and spend some quality time reading great articles on pertussis and VAP prevention in the NICU.
• If you’re planning to attend the AARC Congress in Anaheim, this Dec. 13–16, be sure to come by the section meeting, scheduled for Monday, 11:35 a.m.–12:05 p.m.
• Congress-goers will also want to set aside the 12:30 p.m.–5:05 p.m. time slot on Sunday for the 24th New Horizons Symposium. This year’s session will be devoted to neonatal respiratory care, with talks on everything from surfactant replacement therapy to neonatal extracorporeal life support.
• Learn more about the AARC Congress and the other programs scheduled for neonatal-pediatric RTs in the Advance Program.
• And for an inside look into other aspects of the meeting—including some great videos of last year’s event and a link to things to see and do in Orange County that was constructed especially for the AARC—go here.

Bronchodilator Treatment Called into Question
Bronchodilator treatment in children in respiratory failure due to respiratory syncytial virus bronchiolitis may not be warranted, report researchers publishing in the October 3 Epub edition of Pediatric Critical Care Medicine. The study was conducted by investigators from the departments of pediatrics, respiratory therapy, nursing, and internal medicine at Children’s Hospital at Dartmouth and Dartmouth Medical School in Lebanon, NH. They administered four agents—norepinephrine, levalbuterol, racemic albuterol, and normal saline—at six hour intervals to 22 patients who were intubated, sedated, and receiving mechanical ventilation in a volume control mode, looking at the effect on airway resistance. Results showed small but statistically significant decreases in peak inspiratory pressure after all the bronchodilators. Inspiratory respiratory system resistance dropped significantly following all four of the treatments. However, treatment was also associated with a significant rise in heart rate. “Similar statistically significant bronchodilation occurred after all three bronchodilators as indicated by a decrease in peak inspiratory pressure and respiratory system resistance, but these changes were small and probably clinically insignificant,” write the authors. “However, side effects of bronchodilators, such as tachycardia, also occurred, and these may be clinically significant. Thus the benefit of bronchodilator treatment in these patients is small, does not differ among the drugs we studied and [is] of questionable value.” READ ABSTRACT

Flexible Bronchoscopy During Mechanical Ventilation
Ventilation can be significantly impacted by the insertion of flexible bronchoscopes into endotracheal tubes (ETT) in mechanically ventilated children. Researchers from the University of Washington in Seattle studied the impact of this procedure in a lung model simulating five child sizes based on weight to see how the procedure alters ventilatory parameters such as tidal volume and peak inspiratory pressure (PIP). Twenty-two bronchoscope/ETT combinations were evaluated in both pressure control (PC) ventilation mode and volume control (VC) ventilation mode. Results showed tidal volume decreased in the PC ventilator mode by more than 50% with nine of the combinations. During VC ventilation, PIP increased by >/= 20 cm H2O with seven combinations. Ventilation was severely impaired with the 2.2 mm scope/3.0 mm ETT, 2.8 mm/5.0 mm, and 3.6mm/5.0 mm combinations, while the 3.6 mm/4.5 mm, 5.0 mm/6.5 mm, and 5.0 mm/7.0 mm combinations proved to be incompatible with adequate ventilation. These results, report the authors, suggest clinically relevant decreases in tidal volume can occur with the insertion of bronchoscopes into ETTs when the PC ventilator mode is used, and large increases in PIP result when insertion occurs during VC ventilation. Child size determines the minimum bronchoscope/ETT diameter difference required to maintain adequate ventilation. The investigators published their findings in the September 23 Epub edition of CHEST. READ ABSTRACT

Side Placement Could Minimize VAP Risk
Could placing mechanically ventilated infants on their sides instead of their backs make a big difference in the development of ventilator-associated pneumonia (VAP)? Researchers from George Washington University and Children’s National Medical Center in Washington, DC, believe it’s possible. They tested tracheal cultures in 60 intubated, ventilated infants who were randomly assigned to a lateral group or a supine group. While no statistically significant difference in positive cultures was noted between the two groups after 48 hours of ventilation, results were significantly different after five days, with positive cultures seen in 87% of the supine group versus 30% of the lateral group. More infants in the supine group than the lateral group (21 versus 8) also experienced increased colony counts or had new organisms in their tracheal aspirates. “Gravitational force can ameliorate the onset of respiratory colonization,” write the investigators. “The mechanism and clinical applicability of such observations need to be explored further.” The study was published in the October issue of Pediatrics. READ ABSTRACT

Is Displayed Tidal Volume Reliable?
A new study out of the University of Arkansas for Medical Sciences in Little Rock set out to determine whether tidal volume could be accurately measured at the expiratory valve of a conventional ventilator in a dual control mode of ventilation using internal computer software to compensate for circuit compliance. Researchers measured tidal volume at the endotracheal tube using a pneumotachometer, comparing it with ventilator-displayed tidal volume in 68 patients ranging in age from two days to 18 years. True-delivered tidal volume was generally overestimated by ventilator-displayed tidal volume without circuit compensation, and generally underestimated by ventilator-displayed tidal volume with circuit compensation. Agreement was good, however, between tidal volume measured at the patient’s airway and tidal volume measured with and without compensation for circuit compliance. In both cases, the error with and without circuit compensation was relatively greater in infants and small children. The research was published in the October 3 Epub edition of Pediatric Critical Care Medicine. READ ABSTRACT