Oxygen concentration and pulmonary hemodynamics in newborn lambs with pulmonary hypertension.
The effect of oxygen concentration on lowering pulmonary vascular resistance (PVR) during resuscitation in a model of persistent pulmonary hypertension of the newborn (PPHN) is not known. PPHN was induced in fetal lambs by ductal ligation 9 d before delivery. After delivery by cesarean section, resuscitation of PPHN lambs with 21%, 50%, or 100% O2 (n = 6 each) for 30 min produced similar decreases in PVR. Lambs were then ventilated with 50% O2 for 60 min and exposed to inhaled nitric oxide (iNO, 20 ppm). Initial resuscitation with 100% O2 significantly impaired the subsequent response to iNO compared with 21% O2 (42 +/- 9% vs 22 +/- 4% decrease from baseline PVR). Finally, each lamb was randomly and sequentially ventilated with 10%, 21%, 50%, or 100% O2. PVR decreased with increased concentrations of inhaled O2 up to 50%, there being no additional decrease in PVR with 100% O2. When PVR was correlated with Pao2, the maximal change in PVR was achieved at Pao2 values <60 mm Hg. We conclude that resuscitation with 100% O2 does not enhance pulmonary vasodilation compared with 21% and 50% O2, but impairs the subsequent response to iNO in PPHN lambs. Hypoxia increases PVR but hyperoxia does not confer significant additional pulmonary vasodilation in lambs with PPHN.
Lakshminrusimha
Satyan
S
Department of Pediatrics, State University of New York, Buffalo, New York 14214, USA. slakshmi@buffalo.edu
Swartz
Daniel D
DD
Gugino
Sylvia F
SF
Ma
Chang-Xing
CX
Wynn
Karen A
KA
Ryan
Rita M
RM
Russell
James A
JA
Steinhorn
Robin H
RH
D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure; D004195:Disease Models, Animal; D006439:Hemodynamics; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D008168:Lung / Q000378:metabolism* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D012151:Resuscitation; D012756:Sheep; D013997:Time Factors
D009569:Nitric Oxide; D010100:Oxygen
Neonatology. 2008;94(3):176-82
18612215
Pediatr Pulmonol. 2002 Jun;33(6):437-42
12001276
Am J Physiol Lung Cell Mol Physiol. 2008 Nov;295(5):L881-8
18757525
Pediatr Res. 1999 Nov;46(5):514-22
10541312
Semin Fetal Neonatal Med. 2008 Dec;13(6):368-74
18485848
Am J Physiol Lung Cell Mol Physiol. 2008 Dec;295(6):L979-87
18790993
Arterioscler Thromb Vasc Biol. 2004 Aug;24(8):1367-73
15166009
J Clin Invest. 1966 Mar;45(3):399-411
5904557
Biomed Biochim Acta. 1989;48(2-3):S20-4
2730608
J Perinat Med. 1995;23(5):385-93
8606345
J Pediatr. 1993 May;122(5 Pt 1):743-50
8496755
J Appl Physiol (1985). 2004 Feb;96(2):725-30
14565964
Pediatr Res. 1990 Apr;27(4 Pt 1):372-8
2342829
N Engl J Med. 1997 Feb 27;336(9):605-10
9032045
Pediatrics. 2000 Jan;105(1 Pt 1):14-20
10617698
Am J Physiol Lung Cell Mol Physiol. 2001 Jun;280(6):L1250-7
11350805
Circ Res. 2008 Feb 1;102(2):226-33
17991881
Circ Res. 2003 Apr 4;92(6):683-91
12609968
Am J Respir Crit Care Med. 2006 Dec 15;174(12):1370-7
17008638
Pediatr Res. 2009 Jan;65(1):57-61
18703995
Am J Physiol Heart Circ Physiol. 2003 Jul;285(1):H204-11
12663260
Am J Physiol Lung Cell Mol Physiol. 2003 Dec;285(6):L1354-61
12882761
Pediatr Res. 2006 Jan;59(1):137-41
16326983
Pediatr Res. 1991 Jun;29(6):543-7
1866209
Am J Physiol. 1995 Apr;268(4 Pt 2):H1483-9
7733349
J Pediatr. 2005 Jul;147(1):4-6
16027683
Am J Respir Crit Care Med. 2001 Sep 1;164(5):834-9
11549542
J Perinatol. 2008 Dec;28 Suppl 3:S67-71
19057613
Paediatr Respir Rev. 2005 Sep;6(3):190-8
16153568
Klin Padiatr. 2007 Mar-Apr;219(2):50-7
17373592
Scand J Clin Lab Invest. 1993 Aug;53(5):447-55
8210966
Pediatr Res. 2007 Sep;62(3):313-8
17622960
Am J Respir Crit Care Med. 2004 Nov 1;170(9):1006-13
15184202
Arch Dis Child Fetal Neonatal Ed. 2005 May;90(3):F229-34
15846013
Pediatrics. 2007 Aug;120(2):e272-82
17671038
J Pediatr. 2006 Apr;148(4):564-5
16647429