Objective: To recognize patients with unresponsive septic shock and right ventricular (RV) failure and to evaluate the effects of epinephrine on RV performance in these patients.
Design: Prospective descriptive study.
Setting: Medical intensive care unit.
Subjects: 14 consecutive patients in septic shock unresponsive to fluid loading, dopamine, and dobutamine.
Interventions: Evaluation of RV function by thermodilution with a pulmonary artery catheter equipped with a rapid-response thermistor. Measurements were obtained before and during epinephrine infusion to achieve a systolic arterial pressure > or = 90 mmHg or a mean arterial pressure (MAP) > or = 70 mmHg.
Results: At the time of inclusion in the study the hemodynamic pattern in the 14 patients was as follows: (MAP) 58 +/- 14 mmHg, systemic vascular resistance (SVR) 1046 +/- 437 dyne.s.cm-5.m-2, pulmonary artery occlusion pressure (PAOP) 14 +/- 4 mmHg, mean pulmonary artery pressure (MPAP) 24 +/- 4 mmHg, right arterial pressure (RAP) 11 +/- 4 mmHg, cardiac index (CI) 4 +/- 1.7 l/min per m2. During epinephrine infusion, MAP, CI and stroke volume index (SVI) were increased (27%, p < 0.01; 20%, p < 0.01; 15%, p < 0.05, respectively). There was no change in PAOP, SVR or heart rate. Seven patients (group A) had marked RV failure defined by both RV dilation [RV end-diastolic volume index (RVEDVI) > 92 ml/m2] and low RV ejection factor (RVEF) (< 52%) and 7 did not (group B). Group A had a lower baseline RVEF than group B (24 +/- 7 vs 45 +/- 9%, p < 0.05), a higher RVEDVI (134 +/- 28 vs 79 +/- 17 ml/ m2, p < 0.01), and a higher RVES (systolic) VI (103 +/- 30 vs 43 +/- 11 ml/ m2, p < 0.01). The other hemodynamics, especially RAP and RV stroke work index (RVSWI) were no different in the two groups and did not predict RV dysfunction. In group A, epinephrine infusion improved RVEF (25%, p < 0.05) by a reduction in RVESVI (-8%, p < 0.05) without any change in RVEDVI or in RAP, in spite of a rise in MPAP (11%, p < 0.05). A rise in RVSWI (76%, p < 0.05), SVI (23%, p < 0.05), and CI (24%, p < 0.05) was also achieved. An upward vertical shift of the Frank-Starling relationship RVSWI/ RVEDVI and an upward shift to the left of the pressure volume relationship pulmonary artery peak pressure/RVESVI was observed only in the group with RV failure following treatment with epinephrine. In group B (without RV failure), RV parameters were not modified by epinephrine.
Conclusion: In patients with severe septic shock, RV dysfunction was identified by the use of an RVEF pulmonary artery catheter and was improved by epinephrine by means of an improvement in RV contractility.