TY - JOUR T1 - Restoration of cardiopulmonary function with 21% versus 100% oxygen after hypoxaemia in newborn pigs JF - Archives of Disease in Childhood - Fetal and Neonatal Edition JO - Arch Dis Child Fetal Neonatal Ed SP - F229 LP - FF234 DO - 10.1136/adc.2004.056986 VL - 90 IS - 3 AU - D Fugelseth AU - W B Børke AU - K Lenes AU - I Matthews AU - O D Saugstad AU - E Thaulow Y1 - 2005/05/01 UR - http://fn.bmj.com/content/90/3/F229.abstract N2 - Objective: To assess the consequences of hypoxaemia and resuscitation with room air versus 100% O2 on cardiac troponin I (cTnI), cardiac output (CO), and pulmonary artery pressure (PAP) in newborn pigs.Design: Twenty anaesthetised pigs (12–36 hours; 1.7–2.7 kg) were subjected to hypoxaemia by ventilation with 8% O2. When mean arterial blood pressure fell to 15 mm Hg, or arterial base excess was ⩽ −20 mmol/l, resuscitation was performed with 21% (n  =  10) or 100% (n  =  10) O2 for 30 minutes, then ventilation with 21% O2 for 120 minutes. Blood was analysed for cTnI. Ultrasound examinations of CO and PAP (estimated from tricuspid regurgitation velocity (TR-Vmax)) were performed at baseline, during hypoxia, and at the start of and during reoxygenation.Results: cTnI increased from baseline to the end point (p<0.001), confirming a serious myocardial injury, with no differences between the 21% and 100% O2 group (p  =  0.12). TR-Vmax increased during the insult and returned towards baseline values during reoxygenation, with no differences between the groups (p  =  0.11) or between cTnI concentrations (p  =  0.31). An inverse relation was found between increasing age and TR-Vmax during hypoxaemia (p  =  0.034). CO per kg body weight increased during the early phase of hypoxaemia (p<0.001), then decreased. Changes in CO per kg were mainly due to changes in heart rate, with no differences between the groups during reoxygenation (p  =  0.298).Conclusion: Hypoxaemia affects the myocardium and PAP. During this limited period of observation, reoxygenation with 100% O2 showed no benefits compared with 21% O2 in normalising myocardial function and PAP. The important issue may be resuscitation and reoxygenation without hyperoxygenation. ER -