Lung re-expansion and urinary lipid peroxidation in neonatal pneumothorax.

AIM

Experiential studies suggest that re-expansion of a collapsed lung may result in pulmonary ischaemia-reperfusion injury. We aimed to evaluate the effect of lung re-expansion on urinary lipid peroxidation products in neonates with pneumothorax.

METHODS

This study included 20 mechanically ventilated neonates with pneumothorax, and 18 healthy neonates (controls). A chest tube was inserted immediately following the diagnosis of pneumothorax. Urine samples were obtained just before tube thoracostomy (first period), after one hour (second period), every 12 hours by complete reexpansion (third period). Vital signs and ventilatory parameters were recorded. Urinary lipid peroxidation was evaluated by measurement of thiobarbituric acid-reacting substances (TBARS).

RESULTS

No significant difference was found between urinary TBARS concentrations in the first, second and third periods (4.08 +/- 2.4 nmol/L, 2.8 +/- 2.3 nmol/L and 3.3 +/- 2.1 nmol/L, respectively). Control TBARS levels (4.1 +/- 2.1 nmol/L) did not significantly differ from those of the neonates with pneumothorax (p > 0.05). The neonates with pneumothorax had higher heart rates compared to the controls (p < 0.01). When compared with controls, the systolic pressure was lower in all periods (p < 0.01), and diastolic blood pressure was lower only in the first and second period (p < 0.05). Oxygen saturation significantly decreased in the first period compared to saturation of the second period and of controls (p < 0.01). Ventilatory parameters did not show any significant difference between the periods.

CONCLUSIONS

This prospective study showed that re-expansion of the lung did not significantly affect urinary TBARS concentration in neonatal pneumothorax. Indirectly, short-term lung collapse followed by re-expansion might not cause a clinically significant reperfusion injury in newborns.