Introduction:
Hemodynamic instability is common after resuscitated out-of-hospital cardiac arrest (OHCA). However, data on hemodynamic treatment-goals are sparse. This study investigates mean arterial pressure (MAP) in patients surviving 48 hours after OHCA in relation to organ injury and survival as a post hoc analysis of a large multicenter trial cohort.
Hypothesis:
We hypothesized that low MAP during TTM was associated with more organ injury.
Methods:
Post-hoc analysis of the prospective randomized TTM-trial including 851 comatose OHCA patients surviving more than 48 hours with available blood pressure data. Neuron-specific enolase (NSE) (brain injury) was the primary endpoint and estimated glomerular filtration rate (eGFR) (renal function) was the secondary endpoint.
Measurements and Main Results:
Patients were stratified by mean MAP during TTM in the following groups; <70 mmHg (22%), 70-80 mmHg (43%), and >80 mmHg (35%). NSE at 24, 48 and 72 hours was inversely related to mean MAP: 28 ng/ml [95% confidence interval (CI) 24-33], 26 [23-29], 21 [19-24] ng/mL; p
group
=0.002 for low, intermediate and high MAP groups. After adjusting for potential confounders, this association remained significant (p
group_adjusted
=0.006). A similar result was seen for eGFR (p
group_adjusted
=0.003). Mean MAP was not associated with mortality after 180 days, however higher mean MAP was independently associated with lower odds of renal replacement therapy (odds ratio
adjusted
= 0.75 [95% CI, 0.63-0.88] per 5 mmHg increase; p < 0.001]) (figure 1).
Conclusions:
Lower mean MAP during TTM was independently associated with increased biomarkers of brain injury and initiation of renal replacement therapy in a large cohort of comatose OHCA patients. Increasing blood pressure above the guideline-recommended threshold of 65 mmHg during TTM could potentially mitigate organ injury and be renal-protective. This hypothesis should be investigated in prospective trials.