The induction of mild hypothermia improves systolic function of the resuscitated porcine heart at no further sympathetic activation
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The induction of mild hypothermia improves systolic function of the resuscitated porcine heart at no further sympathetic activation. / Schwarzl, M; Steendijk, P; Huber, S; Truschnig-Wilders, M; Obermayer-Pietsch, B; Maechler, H; Pieske, B; Post, H.
In: ACTA PHYSIOL, Vol. 203, No. 4, 01.12.2011, p. 409-18.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - The induction of mild hypothermia improves systolic function of the resuscitated porcine heart at no further sympathetic activation
AU - Schwarzl, M
AU - Steendijk, P
AU - Huber, S
AU - Truschnig-Wilders, M
AU - Obermayer-Pietsch, B
AU - Maechler, H
AU - Pieske, B
AU - Post, H
N1 - © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.
PY - 2011/12/1
Y1 - 2011/12/1
N2 - AIM: Mild hypothermia (MH) after cardiac arrest attenuates hypoxic brain injury and improves survival. As MH increases contractility in normal hearts, we hypothesized that MH improves cardiovascular function after cardiac arrest.METHODS: In 16 anaesthetized pigs (64 ± 2 kg), ventricular fibrillation was induced electrically for 5 min. At 10 min after resuscitation and return of spontaneous circulation (ROSC), pigs were assigned to normothermia (NT, 38°C, n = 8) or MH (33°C, n = 8, intravascular cooling).RESULTS: At ROSC 6 h vs. baseline, heart rate (HR) was unchanged in NT, but decreased in MH. Cardiac output (CO, l min(-1)) decreased in MH (3.5 ± 0.2 vs. 5.5 ± 0.4, P < 0.05) more than in NT (4.8 ± 0.4 vs. 5.7 ± 0.4, P = ns). Mixed venous oxygen saturation decreased in NT (56 ± 2 vs. 66 ± 3%, P < 0.05), but remained constant in MH (64 ± 2 vs. 65 ± 2%) due to a 35% decrease of whole body oxygen consumption. Left ventricular (LV) dP/dt(max) (mmHg s(-1)) decreased in NT (1163 ± 97 vs. 1665 ± 134, P < 0.05), but was preserved in MH (1602 ± 102 vs. 1603 ± 96), whereas LV relaxation was profoundly slowed during MH. Pressure-volume analysis confirmed improved LV systolic function during MH, but also demonstrated decreased LV end-diastolic distensibility, which was further potentiated by right atrial pacing at baseline HR. MH did not increase plasma catecholamine levels. Spectral analysis of heart rate variability revealed reduced sympathetic activation during MH.CONCLUSION: The induction of MH after cardiac resuscitation improves systolic myocardial function without further sympathetic activation. A reduced metabolism during MH outweighs a decreased CO and thereby acts favourably on systemic oxygen supply/demand balance.
AB - AIM: Mild hypothermia (MH) after cardiac arrest attenuates hypoxic brain injury and improves survival. As MH increases contractility in normal hearts, we hypothesized that MH improves cardiovascular function after cardiac arrest.METHODS: In 16 anaesthetized pigs (64 ± 2 kg), ventricular fibrillation was induced electrically for 5 min. At 10 min after resuscitation and return of spontaneous circulation (ROSC), pigs were assigned to normothermia (NT, 38°C, n = 8) or MH (33°C, n = 8, intravascular cooling).RESULTS: At ROSC 6 h vs. baseline, heart rate (HR) was unchanged in NT, but decreased in MH. Cardiac output (CO, l min(-1)) decreased in MH (3.5 ± 0.2 vs. 5.5 ± 0.4, P < 0.05) more than in NT (4.8 ± 0.4 vs. 5.7 ± 0.4, P = ns). Mixed venous oxygen saturation decreased in NT (56 ± 2 vs. 66 ± 3%, P < 0.05), but remained constant in MH (64 ± 2 vs. 65 ± 2%) due to a 35% decrease of whole body oxygen consumption. Left ventricular (LV) dP/dt(max) (mmHg s(-1)) decreased in NT (1163 ± 97 vs. 1665 ± 134, P < 0.05), but was preserved in MH (1602 ± 102 vs. 1603 ± 96), whereas LV relaxation was profoundly slowed during MH. Pressure-volume analysis confirmed improved LV systolic function during MH, but also demonstrated decreased LV end-diastolic distensibility, which was further potentiated by right atrial pacing at baseline HR. MH did not increase plasma catecholamine levels. Spectral analysis of heart rate variability revealed reduced sympathetic activation during MH.CONCLUSION: The induction of MH after cardiac resuscitation improves systolic myocardial function without further sympathetic activation. A reduced metabolism during MH outweighs a decreased CO and thereby acts favourably on systemic oxygen supply/demand balance.
KW - Animals
KW - Cardiac Output
KW - Cardiac Volume
KW - Catecholamines
KW - Diastole
KW - Female
KW - Heart Arrest
KW - Heart Rate
KW - Hypothermia, Induced
KW - Oxygen Consumption
KW - Swine
KW - Systole
U2 - 10.1111/j.1748-1716.2011.02332.x
DO - 10.1111/j.1748-1716.2011.02332.x
M3 - SCORING: Journal article
C2 - 21658179
VL - 203
SP - 409
EP - 418
JO - ACTA PHYSIOL
JF - ACTA PHYSIOL
SN - 1748-1708
IS - 4
ER -
