Effect of hypertonic saline/dextran on post-stenotic myocardial perfusion, metabolism, and function during resuscitation from hemorrhagic shock in anesthetized pigs.
Resuscitation using small volumes of hypertonic saline solutions normalizes cardiac output without fully restoring arterial pressure. This study compared the efficacy of either 7.2% saline/10% dextran 60 (HSDex) or the identical sodium load of normal saline (NS) to improve regional myocardial blood flow (MBF), contractile function, and oxygen metabolism in the presence of a critical coronary stenosis. Fourteen anesthetized, open-chest pigs (25 +/- 3.6 kg) were instrumented to assess left anterior descending coronary artery (LAD) flow, post-stenotic oxygen, and lactate metabolism, regional myocardial segment shortening (SS, sonomicrometry), and MBF (radioactive microspheres). After implementation of a critical LAD-stenosis, shock was induced by hemorrhage (mean arterial pressure (MAP) 45-50 mmHg for 75 min). Resuscitation was started by infusion (2 min) of either HSDex (n = 7,10% of blood loss) or NS (n = 7, 80% of blood loss); 30 min later 6% dextran 60 (10% of blood loss) was administered in both groups. The LAD-stenosis did not affect myocardial metabolism, SS, or MBF at rest. After hemorrhage, MBF remained unchanged from baseline in non-stenotic but decreased by 53% in post-stenotic myocardium (p < .05). The endo-epicardial flow ratio fell below 1.0 in both areas. SS decreased by 10-15% only in post-stenotic myocardium (p < .05). Resuscitation with both HSDex and NS restored cardiac index (CI) but not MAP. MBF increased above baseline values with either solution in non-stenotic while it remained at shock levels in post-stenotic myocardium, where ischemia persisted as evidenced by lactate production and depressed SS. Neither in non-stenotic nor in post-stenotic myocardium was the epi-endocardial flow ratio normalized upon resuscitation with HSDex or NS. We conclude that in the presence of a flow-limiting coronary stenosis, initial fluid resuscitation with both HSDex and the identical sodium load of NS failed to restore perfusion pressure, redistributed MBF in favor of normally perfused myocardium, and did not reverse ischemia in post-stenotic myocardium.
Welte
M
M
Institute for Surgical Research, Ludwig-Maximilians-University-Munich, Germany.
Lackermeier
P
P
Habler
O
O
Kleen
M
M
Kemming
G
G
Frey
L
L
Zwissler
B
B
Messmer
K
K
D000818:Animals; D016887:Cardiopulmonary Resuscitation; D003327:Coronary Disease / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D003911:Dextrans / Q000627:therapeutic use*; D006439:Hemodynamics; D006982:Hypertonic Solutions; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D012462:Saline Solution, Hypertonic; D012771:Shock, Hemorrhagic / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D012965:Sodium Chloride / Q000627:therapeutic use*; D013552:Swine
D003911:Dextrans; D006982:Hypertonic Solutions; D012462:Saline Solution, Hypertonic; C104375:hypertonic saline-dextran solution; D012965:Sodium Chloride