Incomplete protection by prophylactic surfactant against the adverse effects of large lung inflations at birth in immature lambs
Tóm tắt
To investigate whether preceding surfactant instillation prevents the harmful effect of large lung inflations at birth in immature lambs, and, if not, to find out for how long the immature lung remains sensitive to large inflations. In an exploratory study, 12 preterm lambs given surfactant at birth were randomized to receive five large lung inflations at four different times: at birth just before or immediately after surfactant treatment; at 10 min; or at 60 min of age. In a confirmatory study, 10 pairs of preterm lamb twins were all given surfactant before the first breath. One lamb in each pair was randomised to receive large lung inflations immediately after surfactant while the other twin underwent similar inflations at 10–15 min of age. Animal laboratory. Anaesthetized lambs delivered by cesarean section at a gestational age of 127 days. Surfactant supplementation at birth. Five sustained lung inflations of 16 ml/kg at different times in relation to surfactant instillation. Pressure-limited mechanical ventilation for 4 h. The response to surfactant was assessed by ventilator settings, lung mechanics and lung histology. Preceding surfactant supplementation did not prevent the adverse effect of large lung inflations at birth on ventilatory efficiency and lung mechanics, but seemed to protect against severe lung injury. No adverse effect was seen from large lung inflations given at 10 min of age or later. Prophylactic surfactant supplementation does not fully protect against the harmful effect of large lung inflations during a short sensitive period immediately after birth.
Tài liệu tham khảo
Halbower AC, Jones Jr MD (1999) Physiologic reflexes and their impact on resuscitation of the newborn. Clin Perinatol 26:621–627
Avery ME, Tooley WH, Keller JB, Hurd SS, Bryan MH, Cotton RB, Epstein MF, Fitzhardinge PM, Hansen CB, Hansen TN (1987) Is chronic lung disease in low birth weight infants preventable? A survey of eight centers. Pediatrics 79:26–30
Garland JS, Buck RK, Allred EN, Leviton A (1995) Hypocarbia before surfactant therapy appears to increase bronchopulmonary dysplasia risk in infants with respiratory distress syndrome. Arch Pediatr Adolesc Med 149:617–622
Salhab WA, Perlman JM (1998) Initial PaCO2 values at one hour in very low-birthweight infants(VLBW)<1000 g and oxygen requirement at 28 days: are delivery room events important? Pediatr Res 43:193A (Abstract)
Van Marter LJ, Allred EN, Pagano M, Sanocka U, Parad R, Moore M, Susser M, Paneth N, Leviton A (2000) Do clinical markers of barotrauma and oxygen toxicity explain interhospital variation in rates of chronic lung disease? The Neonatology Committee for the Developmental Network. Pediatrics 105:1194–1201
Jobe AH, Ikegami M (1998) Mechanisms initiating lung injury in the preterm. Early Hum Dev 53:81–94
Clark RH (1999) Support of gas exchange in the delivery room and beyond: How do we avoid hurting the baby we seek to save? Clin Perinatol 26:669–681
Cummings J, Holm B, Nickerson PA, Ferguson WH, Egan E (1995) Pre- versus post-ventilatory surfactant treatment in surfactant-deficient preterm lambs. Reprod Fertil Dev 7:1333–1338
Ikegami M, Kallapur S, Michna J, Jobe AH (2000) Lung injury and surfactant metabolism after hyperventilation of premature lambs. Pediatr Res 47:398–404
Wada K, Jobe AH, Ikegami M (1997) Tidal volume effects on surfactant treatment responses with the initiation of ventilation in preterm lambs. J Appl Physiol 83:1054–1061
Björklund LJ, Ingimarsson J, Curstedt T, John J, Robertson B, Werner O, Vilstrup CT (1997) Manual ventilation with a few large breaths at birth compromises the therapeutic effect of subsequent surfactant replacement in immature lambs. Pediatr Res 42:348–355
Björklund LJ, Ingimarsson J, Curstedt T, Larsson A, Robertson B, Werner O (2001) Lung recruitment at birth does not improve lung function in immature lambs receiving surfactant. Acta Anaesthesiol Scand 45:986–993
Grossmann G, Nilsson R, Robertson B (1986) Scanning electron microscopy of epithelial lesions induced by artificial ventilation of the immature neonatal lung; the prophylactic effect of surfactant replacement. Eur J Pediatr 145:361–367
Vilstrup CT, Björklund LJ, Werner O, Larsson A (1996) Lung volumes and pressure–volume relations of the respiratory system in small ventilated neonates with severe respiratory distress syndrome. Pediatr Res 39:127–133
Vilstrup CT, Björklund LJ, Larsson A, Lachman B, Werner O (1992) Functional residual capacity and ventilation homogeneity in mechanically ventilated small neonates. J Appl Physiol 73:276–283
Ingimarsson J, Björklund LJ, Curstedt T, Jonson B, Larsson A, Robertson B, Werner O (2001) Uneven distribution of exogenous surfactant after hyperinflation of the lungs at birth in immature lambs. Pediatr Res 49:383A (Abstract)
Grossmann G, Robertson B (1975) Lung expansion and the formation of the alveolar lining layer in the fullterm newborn rabbit. Acta Paediatr Scand 64:7–16
Bland RD, McMillan DD, Bressack MA, Dong L (1980) Clearance of liquid from lungs of newborn rabbits. J Appl Physiol 49:171–177
Narendran V, Donovan EF, Hoath SB, Akinbi HT, Steichen JJ, Jobe AH (2003) Early bubble CPAP and outcomes in ELBW infants. J Perinatol 23:195–199
Stenson B (2000) Resuscitation of extremely preterm infants: the influence of positive pressure, surfactant replacement and supplemental oxygen on outcome. In: Hansen T, McIntosh N (eds) Current topics in neonatology, vol 4. Saunders, London, pp 125–148
Finer NN, Rich W, Craft A, Henderson C (2001) Comparison of methods of bag and mask ventilation for neonatal resuscitation. Resuscitation 49:299–305