Abstract
To investigate the role of high frequency oscillation (HFO) in promoting meconium clearance from the airway, we used a commercially available ventilator configured with maximal expiratory flow exceeding inspiratory flow(asymmetric HFO or AHFO). We hypothesized that AHFO would move meconium in an expiratory direction (toward the ventilator). We first tested our hypothesis in vitro and, later, in vivo using the neonatal piglet .In vitro experiments using a Plexiglas airway confirmed meconium movement in an expiratory direction when bias ratio was ≥2. For in vivo experiments, each piglet received a 3 mL/kg intratracheal bolus of a 44 g/100 mL meconium mixture followed by 45 min of mechanical ventilation. Then, in part 1, the piglet was placed in a 15 ° head down tilt position and randomized to either AHFO [ratio of inspiratory time/expiratory time (I:E) of 70:30] or HFO (I:E ratio of 30:70). After 30 min of either AHFO or HFO, the piglet was crossed over to the alternate strategy for an additional 30 min. For part 2, we maintained the piglet on either AHFO or HFO continuously for 4 h. Results demonstrate that, although there was a tendency for larger volumes of meconium to be aspirated from the airway during AHFO in part 1 experiments, there was no difference found in part 2. We also found no significant differences in blood gases or hemodynamic measurements between AHFO and HFO during the prolonged observation period in part 2 of our study. We conclude that AHFO is of no benefit in the treatment of meconium aspiration syndrome.
Similar content being viewed by others
Log in or create a free account to read this content
Gain free access to this article, as well as selected content from this journal and more on nature.com
or
Abbreviations
- HFO:
-
high frequency oscillation
- AHFO:
-
asymmetric high frequency oscillation
- I:E:
-
ratio of inspiratory time/expiratory time
- MAS:
-
meconium aspiration syndrome
- Paw:
-
mean airway pressure
References
Wiswell TE, Bent RC 1993 Meconium aspiration syndrome: unresolved issues. Pediatr Clin N Am 40: 955–981.
Morin FC, Stenmark KR 1995 Persistent pulmonary hypertension of the newborn. Am J Respir Crit Care Med 151: 2010–2032.
Freitag L, Long WM, Kim CS, Wanner A 1989 Removal of excessive bronchial secretions by asymmetric high-frequency oscillations. J Appl Physiol 67: 614–619.
King M, Zidulka A, Phillips DM, Wight D, Gross D, Chang HK 1990 Tracheal mucus clearance in high-frequency oscillation: effect of peak flow rate bias. Eur Respir J 3: 6–13.
Benjamin RG, Chapman GA, Kim CS, Sackner MA 1989 Removal of bronchial secretions by two-phase gas liquid transport. Chest 95: 658–663.
Wiswell TE, Peabody SS, Davis JM, Slayter MV, Bent RC, Merritt TA 1994 Surfactant therapy and high-frequency jet ventilation in the management of a piglet model of the meconium aspiration syndrome. Pediatr Res 36: 494–500.
Bent R, Wiswell TE, Chang A 1992 Removing meconium from infant tracheae. What works best?. Am J Dis Child 146: 1085–1089.
Rubin BK, Tomkiewicz RP, Patrinos ME, Easa D 1996 The surface and transport properties of meconium and reconstituted meconium solutions. Pediatr Res 40: 834–838.
Easa D, Uyehara CFT, Stevens EL, Finn KC, Balaraman V, Sim H 1993 Pancuronium does not alter the hemodynamic status of piglets after normoxia or hypoxia. Pediatr Res 33: 365–372.
Davis JM, Dickerson B, Metlay L, Penney DP 1991 Differential effects of oxygen and barotrauma on lung injury in the neonatal piglet. Pediatr Pulmonol 10: 157–163.
Chang HK, Weber ME, King M 1988 Mucus transport by high-frequency nonsymmetrical oscillatory airflow. J Appl Physiol 65: 3: 1203–1209.
Kim CS, Rodriguez CR, Eldridge MA, Sackner MA 1986 Criteria for mucus transport in the airways by two-phase gas-liquid flow mechanism. J Appl Physiol 60: 901–907.
Kim CS, Iglesias AJ, Sackner MA 1987 Mucus clearance by two-phase gas-liquid flow mechanism: asymmetric periodic flow model. J Appl Physiol 62: 3:959-971
McEvoy RD, Davies NJH, Hedenstierna G, Hartman MT, Spragg RG, Wagner PD 1982 Lung mucociliary transport during high frequency ventilation. Am Rev Respir Dis 126: 452–456.
George RJD, Johnson MA, Pavia D, Agnew JE, Clarke SW, Geddes DM 1985 Increase in mucociliary clearance in normal man induced by oral high frequency oscillation. Thorax 40: 433–437.
Courtney SE, Weber KR, Spohn WA, Bender CV, Malin SW, Gotshall RW 1992 Cardiorespiratory effects of changing inspiratory to expiratory ratio during high-frequency oscillation in an animal model of respiratory failure. Pediatr Pulmonol 13: 113–116.
Findlay RD, Taeusch HW, Walther FJ 1996 Surfactant replacement therapy for meconium aspiration syndrome. Pediatrics 97: 48–52.
Acknowledgements
The authors thank the U.S. Army Health Services Command, Kapiolani Medical Center for Women and Children, and Sensormedics Corporation. We also thank the staff of the Hospital Laboratory and Dr. Jeffrey L. Killeen who performed the lung pathology studies, as well as the nursing staff who collected meconium. We acknowledge the technical expertise of Dr. Oscar Ramirez, Dr. Robert Tomkiewicz, Dr. Chikako Kishioka, and Titik Dian for analysis of meconium properties.
Author information
Authors and Affiliations
Additional information
Supported in part by the Research Centers in Minority Institutions Award, P20 RR/AI 11091, from the National Center for Research Resources, National Institutes of Health, and the Leahi Fund of the Hawaii Community Foundation.
The views expressed in this manuscript are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.
Rights and permissions
About this article
Cite this article
Patrinos, M., Balaraman, V., Ku, T. et al. Promoting Meconium Clearance from the Lungs of the Neonatal Piglet with Asymmetric High Frequency Oscillation. Pediatr Res 42, 342–347 (1997). https://doi.org/10.1203/00006450-199709000-00015
Received:
Accepted:
Issue date:
DOI: https://doi.org/10.1203/00006450-199709000-00015
