Pulmonary function in infancy and in childhood following mechanical ventilation in the neonatal period

Abstract

Pulmonary function was evaluated in both infancy and childhood in the same 19 prematurely born infants, who required mechanical ventilation (MV) during the neonatal period. Results of our patients were compared with those of control subjects. Upon first evaluation, we found that lung resistance (RL) was significantly elevated (24.85 +/- 6.06 vs. 17.77 +/- 2.39 cmH2O/L/s; P less than 0.01). The mean value of dynamic lung compliance (CLdyn) was low, but the difference compared to controls did not reach significance. From infancy to childhood, elevated RL persisted (9.33 +/- 2.51 vs. 6.52 +/- 1.52 cm H2O/L/s; P less than 0.01), and the decrease of CLdyn became significant (46.86 +/- 12.84 vs. 59.34 +/- 15.68 mL/cmH2O; P less than 0.05). In addition, maximum flow at functional residual capacity was significantly decreased (0.824 +/- 0.284 vs. 1.215 +/- 0.358 L/s; P less than 0.01); whereas pulmonary diffusing capacity for carbon monoxide was similar in the patients (7.62 +/- 2.16 mL/min/mm Hg) and in the controls (8.38 +/- 1.6). Pulmonary dysfunction following premature birth, respiratory distress, and prolonged MV may not resolve from infancy to childhood.

Bronchial Lability and Responsiveness in School Children Born Very Preterm

“…However, in our children, the level of obstruction was more severe, possibly because of the difference in selection; our children were more premature than those examined in previous studies. As the numbers of VLBW survivors have increased, mild to moderate obstructive airway dysfunction at school age has been found in children without a history of BPD, as in our study (8)(9)(10)(11)(12)(13)(14). The definition of BPD that we used (oxygen dependency at the age of 36 postconceptional wk) (16) seems to be a sensitive predictor of abnormal pulmonary outcome in VLBW children at school age; 83% of the BPD children had bronchial obstruction.…”

“…In follow-up studies of pulmonary function, BPD is associated with bronchial obstruction and hyperresponsiveness, persisting until school age or young adulthood (1)(2)(3)(4)(5)(6)(7)(8). However, prematurely born children without BPD have also been observed to have obstructed airway function in childhood (8)(9)(10)(11)(12)(13). Despite obstructive changes in spirometry, prematurely born children are often asymptomatic (2).…”

Respiratory mechanics in ventilated preterm infants: early determinants and outcome

“…201 Airway resistance further increases by damage and destruction of airways (airway plugging with cellular debris), airway inflammation with peribronchial oedema and increased mucus production, and airway wall thickening by increased airway smooth muscle mass also exhibiting bronchospasms. 80,84,106,151,201 Increased baseline airway resistance is only partly reversible by inhaled bronchodilators and systemic corticosteroids. 201 Static compliance is decreased, but may be increased if damage to the lung is sufficient to result in loss of elastic recoil.…”

“…9,224 In preterm infants, neonatal respiratory system compliance (Crs) and resistance (Rrs) are indicative of long-term respiratory morbidity, 30,85,151,153,179,193 which may reflect BHR during childhood. 174,181,195,223 More information about causal factors of BHR development is needed to elucidate the pathological process of BHR development in preterm infants.…”

“…94,151,196,275 Only one of these studies consequently performed serial respiratory function measurements in 24 infants, who developed CLD, during the first 2 years of life commencing in the neonatal period. 15 It would therefore be interesting to summarize the results of chapters 6 and 7 of this thesis and show the complete course of respiratory function from the neonatal period until 2 years of age.…”