Left-Sided Ventricular-arterial Coupling and Volume Responsiveness in Septic Shock Patients

The value of right ventricular pulmonary artery coupling in determining the prognosis of patients with sepsis

The outcomes of patients with sepsis are influenced by the contractile function of the right ventricle (RV), but the impact of cardiopulmonary interaction in ICU-mortality of sepsis patients remains unclear. This study aims to investigate the ICU-mortality impact of right ventricular-pulmonary artery (RV-PA) coupling in patients with sepsis. We employed echocardiography to assess patients with sepsis within the initial 24 h of their admission to the ICU. RV-PA coupling was evaluated using the tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP) ratio. A total of 92 subjects were enrolled, with 55 survivors and 37 non-survivors. TAPSE/PASP ratio assessed mortality with an area under the curve (AUC) of 0.766 (95% CI 0.670-0.862) and the optimal cutoff value was 0.495 mm/mmHg. We constructed a nomogram depicting the TAPSE/PASP in conjunction with IL-6 and Lac for the joint prediction of sepsis prognosis, and demonstrated the highest predictive capability (AUC = 0.878, 95% CI 0.809-0.948). In conclusion, the TAPSE/PASP ratio demonstrated prognostic value for ICU mortality in sepsis patients. The nomogram, which combines the TAPSE/PASP, IL-6, and LAC, demonstrated enhanced predictive efficacy for the prognosis of sepsis patients.

Optimizing left ventricular-arterial coupling during the initial resuscitation in septic shock – a pilot prospective randomized study

Background

Left ventricular-arterial coupling (VAC), defined as the ratio of effective arterial elastance (Ea) to left ventricular end-systolic elastance (Ees), has been extensively described as a key determinant of cardiovascular work efficacy. Previous studies indicated that left ventricular-arterial uncoupling was associated with worse tissue perfusion and increased mortality in shock patients. Therefore, this study aims to investigate whether a resuscitation algorithm based on optimizing left VAC during the initial resuscitation can improve prognosis in patients with septic shock.

Methods

This pilot study was conducted in an intensive care unit (ICU) of a tertiary teaching hospital in China. A total of 83 septic shock patients with left ventricular-arterial uncoupling (i.e., the Ea/Ees ratio ≥ 1.36) were randomly assigned to receive usual care (usual care group, n = 42) or an algorithm-based resuscitation that attempt to reduce the Ea/Ees ratio to 1 within the first 6 h after randomization (VAC-optimized group, n = 41). The left VAC was evaluated by transthoracic echocardiography every 2 h during the study period. The primary endpoint was 28-days mortality. The secondary endpoints included lactate clearance rate, length of ICU stay, and duration of invasive mechanical ventilation (IMV).

Results

Eighty-two patients (98.8%) completed the study and were included in the final analysis. The Ea/Ees ratio was reduced in both groups, and the decrease in Ea/Ees ratio in the VAC-optimized group was significantly greater than that in the usual care group [median (interquartile range), 0.39 (0.26, 0.45) vs. 0.1 (0.06, 0.22); P < 0.001]. Compared with the usual care group, the VAC-optimized group likely exhibited the potential to reduce the 28-days mortality (33% vs. 50%; log-rank hazard ratio = 0.526, 95% confidence interval: 0.268 to 1.033). Moreover, the VAC-optimized group had a higher lactate clearance rate than the usual care group [27.7 (11.9, 45.7) % vs. 18.3 (− 5.7, 32.1) %; P = 0.038]. No significant difference was observed in terms of the length of ICU stay or duration of IMV.

Conclusions

During the initial resuscitation of septic shock, optimizing left ventricular-arterial coupling was associated with improved lactate clearance, while likely having a beneficial effect on prognosis.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1900024031. Registered 23 June 2019 - Retrospectively registered.

Cardiovascular Responses During Sepsis

Sepsis is the life-threatening organ dysfunction arising from a dysregulated host response to infection. Although the specific mechanisms leading to organ dysfunction are still debated, impaired tissue oxygenation appears to play a major role, and concomitant hemodynamic alterations are invariably present. The hemodynamic phenotype of affected individuals is highly variable for reasons that have been partially elucidated. Indeed, each patient's circulatory condition is shaped by the complex interplay between the medical history, the volemic status, the interval from disease onset, the pathogen, the site of infection, and the attempted resuscitation. Moreover, the same hemodynamic pattern can be generated by different combinations of various pathophysiological processes, so the presence of a given hemodynamic pattern cannot be directly related to a unique cluster of alterations. Research based on endotoxin administration to healthy volunteers and animal models compensate, to an extent, for the scarcity of clinical studies on the evolution of sepsis hemodynamics. Their results, however, cannot be directly extrapolated to the clinical setting, due to fundamental differences between the septic patient, the healthy volunteer, and the experimental model. Numerous microcirculatory derangements might exist in the septic host, even in the presence of a preserved macrocirculation. This dissociation between the macro- and the microcirculation might account for the limited success of therapeutic interventions targeting typical hemodynamic parameters, such as arterial and cardiac filling pressures, and cardiac output. Finally, physiological studies point to an early contribution of cardiac dysfunction to the septic phenotype, however, our defective diagnostic tools preclude its clinical recognition. © 2021 American Physiological Society. Compr Physiol 11:1605-1652, 2021.