Vasopressor requirement during targeted temperature management for out-of-hospital cardiac arrest caused by acute myocardial infarction without cardiogenic shock

Abstract

Objective: We investigated whether patients with out-of-hospital cardiac arrest (OHCA) due to an acute myocardial infarction without cardiogenic shock required higher doses of vasopressors with low targeted temperature management (TTM) after return of spontaneous circulation.

Methods: We included consecutive comatose patients resuscitated from OHCA between January 2011 and December 2013. Patients with return of spontaneous circulation, regional wall motion abnormality on echocardiography, and coronary artery stenosis of ≥70% on percutaneous coronary artery angiography were enrolled. These patients received 36°C TTM or 33°C TTM following approval of TTM by patients' next-of-kin (36°C and 33°C TTM groups, respectively). The cumulative vasopressor index was compared between groups.

Results: During induction phase, dose of vasopressors did not differ between groups. In the maintenance phase, the norepinephrine dose was 0.37±0.57 and 0.26±0.91 µg·kg^-1·min^-1 in the 33°C and 36°C TTM groups, respectively (P<0.01). During the rewarming phase, the norepinephrine and dopamine doses were 0.49±0.60 and 9.67±9.60 mcg·kg^-1·min^-1 in the 33°C TTM group and 0.14±0.46 and 3.13±7.19 mcg·kg^-1·min^-1 in the 36°C TTM group, respectively (P<0.01). The median cumulative vasopressor index was 8 (interquartile range, 3 to 8) and 4 (interquartile range, 0 to 8) in the 33°C and 36°C TTM groups, respectively (P=0.03).

Conclusion: In this study, patients with OHCA due to acute myocardial infarction without cardiogenic shock had an elevated vasopressor requirement with 33°C TTM compared to 36°C TTM during the maintenance and rewarming phases.

Keywords: Hypothermia; Myocardial infarction; Vasoconstrictor agents.

Fig. 1.

Flow chart. The flow diagram shows patients admitted to a single hospital after out-of-hospital cardiac arrest (OHCA) from 2011 to 2013. ROSC, return of spontaneous circulation; GCS, Glasgow Coma Scale; PCI, percutaneous coronary intervention; AMI, acute myocardial infarction; TTM, targeted temperature management.

Fig. 2.

These images show the arterial pressure in the 36℃ and the 33℃ targeted temperature management (TTM) groups. Dashed lines represent interquartile range while circles represent median value. (A) systolic arterial pressure (SAP), (B) diastolic arterial pressure (DAP), and (C) mean arterial pressure (MAP). There were no significant differences of arterial pressure between groups during the induction phase. However, systolic arterial pressure and mean arterial pressure were lower in the 33℃ TTM group than in the 36°C TTM group during the maintenance phase. Systolic arterial pressure, diastolic pressure and mean arterial pressure were lower in the 33℃ TTM group than in the 36℃ TTM group in rewarming phase.

Fig. 3.

These images show the mean core body temperature in the 36℃ targeted temperature management (TTM) and the 33℃ TTM groups. Dashed lines represent interquartile range while circles represent median value.