Heart rate reduction with esmolol in septic shock: effects on microcirculation

Introduction

Preclinical and clinical studies report that β-blockers may be an interesting option to attenuate the deleterious effects of prolonged catecholamine exposure during septic shock. Nevertheless, there are concerns that β-blockers may have negative chronotropic and inotropic effects leading to inappropriately low cardiac output. The objective of the present study was therefore to elucidate whether a reduction in heart rate (HR) with esmolol may negatively affect microcirculation in patients with septic shock who remained tachycardic after hemodynamic optimization.

Methods

After 36 hours of initial hemodynamic stabilization, 11 septic shock patients with HR >95 bpm and requiring norepinephrine (NE) to maintain mean arterial pressure (MAP) between 65 and 75 mmHg, despite adequate volume resuscitation, received a continuous esmolol infusion to maintain HR between 94 and 80 bpm. NE was titrated to achieve a MAP between 65 and 75 mmHg. Data from right heart catheterization and sidestream dark-field imaging were obtained at baseline and after 24 hours.

Results

Apart from a statistically significant decrease in HR and cardiac index (CI) (P < 0.05), stroke volume (SV), microvascular flow index of the small vessels (MFIs) and norepinephrine requirements did not vary during the 24-hour observational period. Results are summarized in Table 1.

Table 1

Conclusion

In patients with established septic shock who remained tachycardic after hemodynamic optimization in accordance with the current guidelines, titration of esmolol to reduce the HR to a predefined threshold did not affect microcirculatory blood flow.