EFFECTS OF EPINEPHRINE ON RIGHT-VENTRICULAR FUNCTION IN PATIENTS WITHSEVERE SEPTIC SHOCK AND RIGHT-VENTRICULAR FAILURE - A PRELIMINARY DESCRIPTIVE STUDY

Objective: To recognize patients with unresponsive septic shock and ri ght ventricular (RV) failure and to evaluate the effects of epinephrin e 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 therm istor. Measurements were obtained before and during epinephrine infusi on to achieve a systolic arterial pressure greater than or equal to 90 mmHg or a mean arterial pressure (MAP) greater than or equal to 70 mm Hg. Results: At the time of inclusion in the study the hemodynamic pat tern in the 14 patients was as follows. (MAP) 58 +/- 14 mmHg, systemic vascular resistance (SVR) 1046 +/- 437 dyne . s . cm(-5) . m(-2), pul monary 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 m(2). During epineph rine infusion, MAP, CI and stroke volume index (SVI) were increased (2 7 %, p < 0.01; 20 %, p < 0.01; 15 %, p < 0.05, respectively). There wa s no change in PAOP, SVR or heart rate. Seven patients (group A) had m arked RV failure defined by both RV dilation [RV end-diastolic volume index (RVEDVI) > 92 ml/m(2)] and low RV ejection factor (RVEF) (< 52 % ) and 76 did not (group B). Group A had a lower baseline RVEF than gro up B (24 +/- 7 vs 45 +/- 9 %, p < 0.05), a higher RVEDVI (134 +/- 28 v s 79 +/- 17 ml/m(2), p < 0.01), and a higher RVES (systolic) VI (103 /- 30 vs 43 +/- 11 ml/m(2), p < 0.01). The other hemodynamics, especia lly RAP and RV stroke work index (RVSWI) were no different in the two groups and did not predict RV dysfunction. In group A, epinephrine inf usion 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) was also achieved. An upward vertical shift of the Frank-Star ling relationship RVSWI/RVEDI and an upward shift to the left of the p ressure volume relationship pulmonary artery peak pressure/RVESVI was observed only in the group with RV failure following treatment with ep inephrine. In group B (without RV failure), RV parameters were not mod ified by epinephrine. Conclusion: In patients with severe septic shock , RV dysfunction was identified by the use of RVEF pulmonary artery ca theter and was improved by epinephrine by means of an improvement in R V contractility.