Restoration of cardiopulmonary function with 21% versus 100% oxygen after hypoxaemia in newborn pigs. Issue 3 (21st April 2005)

• Record Type: Journal Article
• Authors: Fugelseth, D; Børke, W B; Lenes, K; Matthews, I; Saugstad, O D; Thaulow, E
• Is Part Of: Archives of disease in childhood. Volume 90:Issue 3(2005)
• Page Start: F229
• Page End: FF234
• Publication Date: 2005-04-21
• Subjects: CO, cardiac output -- cTnI, cardiac troponin I -- LVP, left ventricular pressure -- PAP, pulmonary artery pressure -- TR-Vmax, peak tricuspid regurgitation velocity; resuscitation -- cardiac troponin I -- cardiac output -- pulmonary hypertension -- pig; Infants -- Diseases -- Periodicals; Newborn infants -- Diseases -- Periodicals; Fetus -- Diseases -- Periodicals; 618.920105
• DOI: 10.1136/adc.2004.056986
• Languages: English
• ISSNs: 1359-2998

Abstract

Abstract : 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.