Abstract
BACKGROUND: High-frequency ventilation (HFV) is being used for the treatment of newborn respiratory distress in many intensive care nurseries. Some therapies important to the care of infants receiving HFV, such as endotracheal-tube (ETT) suctioning, have not been thoroughly studied. Suctioning frequently results in the clinical deterioration of the infant and is probably due to the loss of lung volume and oxygen delivery that occurs when the ventilator is disconnected. Although some methods of closed airway suctioning have been used successfully with conventional ventilation, their use with HFV has not been reported. EVALUATION METHOD: We conducted a bench evaluation of the Novametrix Neonatal C/D suction adaptor (CD) in conjunction with the SensorMedics 3100 High Frequency Oscillatory Ventilator. We determined the differences in % CO2 between CD and standard (STD) connectors for three ETT sizes (2.5-, 3.0-, and 3.5-mm at 20-second time intervals). Test-lung CO2 concentrations were sampled and recorded by a clinical capnometer coupled to a recording oscilloscope. Significance of differences was tested by analysis of variance for repeated measures. Resistances to airflow (R) offered by CD and STD, with ETT of the three sizes were compared. RESULTS: The differences in % CO2 were not significant; however, increased resistance was seen with CD. In addition, we were able to show that the presence of the suction catheter in the lumen of the ETT causes only a small pressure rise in the test lung. CONCLUSIONS: The use of the Novametrix Neonatal C/D suction adapter does not affect the performance of the SensorMedics 3100 and thus may be advantageous in the care of the neonate managed on this ventilator. However, the increase in resistances seen with the CD especially when coupled to the 2.5-mm ETT may be clinically important, particularly in the spontaneously breathing patient.
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