Effects of Conventional Mechanical Ventilation Performed by Two Neonatal Ventilators on the Lung Functions of Rabbits with Meconium-Induced Acute Lung Injury

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Abstract

Severe meconium aspiration syndrome (MAS) in the neonates often requires a ventilatory support. As a method of choice, a conventional mechanical ventilation with small tidal volumes (VT<6 ml/kg) and appropriate ventilatory pressures is used. The purpose of this study was to assess the short-term effects of the small-volume CMV performed by two neonatal ventilators: Aura V (Chirana Stara Tura a.s., Slovakia) and SLE5000 (SLE Ltd., UK) on the lung functions of rabbits with experimentally-induced MAS and to estimate whether the newly developed neonatal version of the ventilator Aura V is suitable for ventilation of the animals with MAS.

In the young rabbits, a model of MAS was induced by an intratracheal instillation of a suspension of neonatal meconium (4 ml/kg, 25 mg/ml). After creating the model of MAS, the animals were ventilated with small-volume CMV (frequency 50/min, VT <6 ml/kg, inspiration time 50 %, fraction of inspired oxygen 1.0, positive end-expiratory pressure 0.5 kPa, mean airway pressure 1.1 kPa) performed by ventilator Aura V (Aura group, n=7) or ventilator SLE5000 (SLE group, n=7) for additional 4 hours. One group of animals served as healthy non-ventilated controls (n=6). Blood gases, oxygenation indexes, ventilatory pressures, lung compliance, oxygen saturation and total and differential white blood cell (WBC) count were regularly determined. After euthanizing the animals, a left lung was saline-lavaged and total and differential counts of cells in the bronchoalveolar lavage (BAL) fluid were determined. A right lung was used for estimation of lung edema formation (expressed as a wet/dry weight ratio) and for analysis of concentrations of pro-inflammatory cytokines (IL-1β, IL-8, TNF). The cytokines were measured also in the blood plasma taken at the end of experiment.

Meconium instillation seriously worsened the gas exchange and induced inflammation and lung edema formation. In the Aura group, slightly lower concentrations of cytokines were found and better gas exchange early after creating the MAS model was observed. However, there were no significant differences in the respiratory parameters between the ventilated groups at the end of experiment (P>0.05).

Concluding, the newly developed neonatal version of the ventilator Aura V was found to be fully comparable to widely used neonatal ventilator SLE5000. Results provided by Aura V in CMV ventilation of rabbits with meconium-induced acute lung injury suggest its great potential also for future clinical use, i.e. for ventilation of the neonates with MAS.

1. van Ierland Y, de Beaufort AJ. Why does meconium cause meconium aspiration syndrome? Current concepts of MAS pathophysiology. Early Hum Dev 2009; 85 (10): 617-20.

2. Swarnam K, Soraisham AS, Sivanandan S. Advances in the management of meconium aspiration syndrome. Int J Pediatr 2012; 2012: 359571.

3. Mokra D, Mokry J. Meconium Aspiration Syndrome: From Pathomechanisms to Treatment. New York: Nova Science Publishers Inc.; 2010.

4. Singh BS, Clark RH, Powers RJ, Spitzer AR. Meconium aspiration syndrome remains a significant problem in the NICU: outcomes and treatment patterns in term neonates admitted for intensive care during a ten-year period. J Perinatol 2009; 29 (7): 497-503.

5. Dargaville PA. Respiratory support in meconium aspiration syndrome: a practical guide. Int J Pediatr 2012; 2012: 965159.

6. Chowdhury O, Greenough A. Neonatal ventilatory techniques - which are best for infants born at term? Arch Med Sci 2011; 7 (3): 381-7.

7. Tomcikova L, Mokra D, Pistekova H, Kosutova P, Petraskova M, Javorka K, Jurcek M, Istona P, Calkovska A. Ventilator „Chirana Aura V“ in two models of neonatal acute lung injury – a pilot study. Acta Med Mart 2014; 14 (1): 20-26.

8. Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the Folin phenol reagent. J Biol Chem 1951; 193 (1):265-75.

9. Davey AM, Becker JD, Davis JM. Meconium aspiration syndrome: physiological and inflammatory changes in a newborn piglet model. Pediatr Pulmonol 1993; 16 (2): 101-8.

10. Tyler DC, Murphy J, Cheney FW. Mechanical and chemical damage to lung tissue caused by meconium aspiration. Pediatrics 1978; 62 (4): 454-9.

11. Tran N, Lowe C, Sivieri EM, Shaffer TH. Sequential effects of acute meconium obstruction on pulmonary function. Pediatr Res 1980; 14 (1): 34-8.

12. Moses D, Holm BA, Spitale P, Liu MY, Enhorning G. Inhibition of pulmonary surfactant function by meconium. Am J Obstet Gynecol 1991; 164 (2): 477-81.

13. Kuo C, Chen J. Effect of meconium aspiration on plasma endothelin-1 level and pulmonary hemodynamics in a piglet model. Biol Neonate 1999; 76 (4): 228-34.

14. Sun B, Herting E, Curstedt T, Robertson B. Exogenous surfactant improves lung compliance and oxygenation in adult rats with meconium aspiration. J Appl Physiol (1985) 1994; 77 (4): 1961-71.

15. Hachey WE, Eyal FG, Curtet-Eyal NL, Kellum FE. High-frequency oscillatory ventilation versus conventional ventilation in a piglet model of early meconium aspiration. Crit Care Med 1998; 26 (3): 556-61.

16. Hummler HD, Thome U, Schulze A, Schnabel R, Pohlandt F, Franz AR. Spontaneous breathing during partial liquid ventilation in animals with meconium aspiration. Pediatr Res 2001; 49 (4): 572-80.

17. Robinson TW, Roberts AM. Effects of exogenous surfactant on gas exchange and compliance in rabbits after meconium aspiration. Pediatr Pulmonol 2002; 33 (2): 117-23.

18. Li AM, Zhang LN, Li WZ. Amelioration of meconium-induced acute lung injury by parecoxib in a rabbit model. Int J Clin Exp Med 2015; 8 (5): 6804-12.

19. Mokra D, Calkovska A, Drgova A, Javorka M, Javorka K. Treatment of experimental meconium aspiration syndrome with surfactant lung lavage and conventional vs. asymmetric high-frequency jet ventilation. Pediatr Pulmonol 2004; 38 (4): 285-91.

20. Mokry J, Mokra D, Antosova M, Bulikova J, Calkovska A, Nosalova G. Dexamethasone alleviates meconium-induced airway hyperresponsiveness and lung inflammation in rabbits. Pediatr Pulmonol 2006; 41 (1): 55–60.

21. Mokra D, Mokry J, Drgova A, Petraskova M, Bulikova J, Calkovska A. Intratracheally administered corticosteroids improve lung function in meconium-instilled rabbits. J Physiol Pharmacol 2007; 58 Suppl 5 (Pt 1): 389-98.

22. Mikolka P, Mokrá D, Kopincová J, Tomčíková-Mikušiaková L, Čalkovská A. Budesonide added to modified porcine surfactant Curosurf may additionally improve the lung functions in meconium aspiration syndrome. Physiol Res 2013; 62 (Suppl 1): S191-200.

23. Mikolka P, Kopincová J, Košútová P, Čierny D, Čalkovská A, Mokrá D. Lung inflammatory and oxidative alterations after exogenous surfactant therapy fortified with budesonide in rabbit model of meconium aspiration syndrome. Physiol Res 2016; 65 (Suppl 5): S653-62.

24. Zagariya A, Bhat R, Navale S, Chari G, Vidyasagar D. Inhibition of meconium-induced cytokine expression and cell apoptosis by pretreatment with captopril. Pediatrics 2006; 117 (5): 1722-7.

25. Silvera FE, Blasina MF, Vaamonde L, Tellechea S, Godoy C, Zabala S, Mañana G, Martell M, Olivera W. Sildenafil prevents the increase of extravascular lung water and pulmonary hypertension after meconium aspiration in newborn piglets. Braz J Med Biol Res 2011; 44 (8): 778-85.

Acta Medica Martiniana

The Journal of Comenius University in Bratislava

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