Right heart failure in the intensive care unit:

The prognostic role of tricuspid annular plane systolic excursion in critically ill patients with septic shock

INTRODUCTION

The right ventricle (RV) may play a crucial role in predicting prognosis in critical settings. The value of the tricuspid annular plane systolic excursion (TAPSE) has been shown in the prognosis of cardiac patients, such as those with heart failure and pulmonary hypertension. The aim of this study was to evaluate the possible prognostic performance of RV dysfunction, as assessed by the TAPSE, in noncardiac septic shock patients.

METHODOLOGY

One hundred critically ill adult patients diagnosed with septic shock were enrolled directly after admission. The TAPSE was measured within 24 h. Patients were analyzed according to 28-day mortality and divided into non-survivors and survivors.

RESULTS

The overall 28-day mortality rate was 62%. TAPSE showed a strong negative correlation with APACHE-II (r = - 0.569, p < 0.001) and moderately negatively correlated with the SOFA score (r = - 0.448, p = 0.001). TAPSE (at a cutoff point of 2 cm) was a very good tool (area under curve = 0.887) for predicting 28-day mortality (95% confidence interval CI 0.770-0.980, p < 0.0001).

CONCLUSION

Early echocardiographic assessment of RV dysfunction to measure TAPSE might be of prognostic importance in noncardiac patients with septic shock, as a TAPSE less than 2 cm was useful for predicting poor outcomes.

TRIAL REGISTRATION

clinicaltrials.gov, NCT06008067. Registered 18 July 2023 registered. TAPSESEPTIC study.

Navigating Heart-Lung Interactions in Mechanical Ventilation: Pathophysiology, Diagnosis, and Advanced Management Strategies in Acute Respiratory Distress Syndrome and Beyond

Patients in critical condition who require mechanical ventilation experience intricate interactions between their respiratory and cardiovascular systems. These complex interactions are crucial for clinicians to understand as they can significantly influence therapeutic decisions and patient outcomes. A deep understanding of heart-lung interactions is essential, particularly under the stress of mechanical ventilation, where the right ventricle plays a pivotal role and often becomes a primary concern. Positive pressure ventilation, commonly used in mechanical ventilation, impacts right and left ventricular pre- and afterload as well as ventricular interplay. The right ventricle is especially susceptible to these changes, and its function can be critically affected, leading to complications such as right heart failure. Clinicians must be adept at recognizing and managing these interactions to optimize patient care. This perspective will analyze this matter comprehensively, covering the pathophysiology of these interactions, the monitoring of heart-lung dynamics using the latest methods (including ECHO), and management and treatment strategies for related conditions. In particular, the analysis will delve into the efficacy and limitations of various treatment modalities, including pharmaceutical interventions, nuanced ventilator management strategies, and advanced devices such as extracorporeal membrane oxygenation (ECMO). Each approach will be examined for its impact on optimizing right ventricular function, mitigating complications, and ultimately improving patient outcomes in the context of mechanical ventilation.

A pig model of acute right ventricular afterload increase by hypoxic pulmonary vasoconstriction

Background

The aim of this study was to construct a non-invasive model for acute right ventricular afterload increase by hypoxic pulmonary vasoconstriction. Intact animal models are vital to improving our understanding of the pathophysiology of acute right ventricular failure. Acute right ventricular failure is caused by increased afterload of the right ventricle by chronic or acute pulmonary hypertension combined with regionally or globally reduced right ventricular contractile capacity. Previous models are hampered by their invasiveness; this is unfortunate as the pulmonary circulation is a low-pressure system that needs to be studied in closed chest animals. Hypoxic pulmonary vasoconstriction is a mechanism that causes vasoconstriction in alveolar vessels in response to alveolar hypoxia. In this study we explored the use of hypoxic pulmonary vasoconstriction as a means to increase the pressure load on the right ventricle.

Results

Pulmonary hypertension was induced by lowering the FiO₂ to levels below the physiological range in eight anesthetized and mechanically ventilated pigs. The pigs were monitored with blood pressure measurements and blood gases. The mean pulmonary artery pressures (mPAP) of the animals increased from 18.3 (4.2) to 28.4 (4.6) mmHg and the pulmonary vascular resistance (PVR) from 254 (76) dyns/cm⁵ to 504 (191) dyns/cm⁵, with a lowering of FiO₂ from 0.30 to 0.15 (0.024). The animals’ individual baseline mPAPs varied substantially as did their response to hypoxia. The reduced FiO₂ level yielded an overall lowering in oxygen offer, but the global oxygen consumption was unaltered.

Conclusions

We showed in this study that the mPAP and the PVR could be raised by approximately 100% in the study animals by lowering the FiO₂ from 0.30 to 0.15 (0.024). We therefore present a novel method for minimally invasive (closed chest) right ventricular afterload manipulations intended for future studies of acute right ventricular failure. The method should in theory be reversible, although this was not studied in this work.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-2333-7) contains supplementary material, which is available to authorized users.

Critical Illness in Patients With Asplenia

The critically ill, asplenic patient presents a variety of management challenges. Historically, the focus of the care of the asplenic population has been the prevention and management of infection, including the often-fatal overwhelming postsplenectomy infection with encapsulated organisms such as Streptococcus pneumoniae. Recently, however, there has been increasing recognition of the spleen's function in areas outside of immunity because the asplenic state has been identified as a risk factor for such vascular complications as thrombosis and pulmonary hypertension resulting from dysregulated inflammation and coagulation. Because of the relatively small size of this population and the relative infrequency with which critical illness occurs in it, there are few controlled trials that can serve as a basis for therapeutic maneuvers; thus, optimal management requires an astute clinician with an understanding of the pathogenetic mechanisms underlying the reported consequences of splenectomy. The purpose of this review is to explore the pathophysiology of the asplenic state-impairment in adaptive immunity, loss of blood filtration, endothelial dysfunction, and dysregulated coagulation-and how it leads to infection, thrombosis, and pulmonary hypertension as well as to discuss the implications of these conditions on the management of the critically ill, splenectomized patient.

Effect of positive end-expiratory pressure on porcine right ventricle function assessed by speckle tracking echocardiography

Background

Right ventricle (RV) dysfunction and hypotension can be induced by high levels of positive end-expiratory pressure (PEEP). We sought to determine in an animal model if a novel ultrasound analysis technique: speckle tracking echocardiography (STE), could determine deterioration in RV function induced by PEEP and to compare this to a conventional method of RV analysis: fractional area change (FAC). STE is a sensitive, angle-independent method for describing cardiac deformation (‘strain’) and is particularly useful in analyzing RV function as has been shown in pulmonary hypertension cohorts.

Methods

Ten pigs, 40-90 kg, anaesthetized, fully mechanically ventilated at 6 ml/kg were subject to step-wise escalating levels of PEEP at two-minute intervals (0, 5, 10, 15, 20, 25 and 30cmH₂0). Intracardiac echocardiography was used to image the RV as transthoracic and transesophageal echocardiography did not give sufficient image quality or flexibility. Off-line STE analysis was performed using Syngo Velocity Vector Imaging (Seimens Medical Solutions Inc., USA). STE systolic parameters are RV free wall strain (RVfwS) and strain rate (RVfwSR) and the diastolic parameter RV free wall strain rate early relaxation (RVfwSRe)

Results

With escalating levels of PEEP there was a clear trend of reduction in STE parameters (RVfwS, RVfwSR, RVfwSRe) and FAC. Significant hypotension (fall in mean arterial blood pressure of 20 mmHg) occurred at approximately PEEP 15 cmH₂O. Comparing RVfwS, RVfwSR and RVfwSRe values at different PEEP levels showed a significant difference at PEEP 0 cmH₂O vs PEEP 10 cmH₂O and above. FAC only showed a significant difference at PEEP 0 cmH₂O vs PEEP 20 cmH₂O and above. 30% of pigs displayed dyssychronous RV free wall contraction at the highest PEEP level reached.

Conclusions

STE is a sensitive method for determining RV dysfunction induced by PEEP and deteriorated ahead of a conventional assessment method: FAC. RVfwS decreased to greater extent compared to baseline than FAC, earlier in the PEEP escalation process and showed a significant decrease before there was a clinical relevant decrease in mean arterial blood pressure. Studies in ICU patients using transthoracic echocardiography are warranted to further investigate the most sensitive echocardiography method for detecting RV dysfunction induced by mechanical ventilation.

Tricuspid Annular Plane Systolic Excursion and Its Association with Mortality in Critically Ill Patients

BACKGROUND

Transient left ventricular dysfunction can occur under conditions of extreme emotional or physiological stress. There is little data on right ventricular function in such situations.

METHODS

One hundred twenty patients admitted to an ICU with a noncardiac illness were studied. Those with documented coronary disease, ejection fraction <40%, sepsis, or intracranial hemorrhage were excluded. Echocardiograms were performed within 24 hours of admission. Tricuspid annular plane systolic excursion (TAPSE) was measured to assess right ventricular systolic function. Plasma catecholamines (norepinephrine, epinephrine, dopamine) were measured on admission. Clinical and demographic data were collected, along with data on ICU length of stay (LOS), hospital LOS, and in-hospital and long-term mortality. TAPSE was tested for correlation with adverse outcomes and length of stay.

RESULTS

Mean TAPSE for the group was 2.05 ± 0.66 cm. Based on area under the ROC curve analysis, TAPSE <2.4 cm was the best cutoff for predicting in-hospital and long-term mortality. There were 13 in-hospital deaths, 12 in the group with TAPSE <2.4 cm and one among those with TAPSE ≥2.4 cm. On multivariate analysis, TAPSE <2.4 cm was a significant predictor of in-hospital mortality (χ(2)  = 4.6, P = 0.03). When tested against hospital LOS, an inverse correlation was found (P = 0.04). No association was found between TAPSE and catecholamine levels.

CONCLUSIONS

Right ventricular systolic function, as assessed by TAPSE, has important prognostic value in critically ill patients. Mean values were lower in patients who died in-hospital versus those who survived to discharge. In addition, patients with TAPSE <2.4 cm had a longer hospital length of stay.

Management of right ventricular dysfunction in the perioperative setting

PURPOSE OF REVIEW

This review summarizes the approach to and recent developments in the treatment of acute right ventricular dysfunction and failure in the perioperative setting. Right ventricular failure, defined as the inability to deliver sufficient blood flow through the pulmonary circulation at normal central venous pressure, is a common problem in the perioperative setting and is associated with an increased mortality. The failure of the right ventricle is caused by reduced right ventricular contractility or an increased right ventricular afterload or both.

RECENT FINDINGS

Management of acute right ventricular failure continues to be challenging because of the poor understanding of the pathophysiology, difficulties in diagnosing, the absence of guidelines, and limited therapeutic options. Recent research efforts have led to an improved understanding of the underlying mechanisms and have established a reasonable therapeutic framework.

SUMMARY

Right ventricular dysfunction may cause venous congestion and systemic hypoperfusion. After identifying right ventricular dysfunction, the primary goal is to correct reversible causes of excessive load or reduced right-ventricular contractility. If the underlying abnormalities cannot be reversed, diuretic, vasodilator, or inotropic therapy may be required.

Matrix metalloproteinase inhibition attenuates right ventricular dysfunction and improves responses to dobutamine during acute pulmonary thromboembolism

Activated matrix metalloproteinases (MMPs) cause cardiomyocyte injury during acute pulmonary thromboembolism (APT). However, the functional consequences of this alteration are not known. We examined whether doxycycline (a MMP inhibitor) improves right ventricle function and the cardiac responses to dobutamine during APT. APT was induced with autologous blood clots (350 mg/kg) in anaesthetized male lambs pre-treated with doxycycline (Doxy, 10 mg/kg/day, intravenously) or saline. Non-embolized control lambs received doxycycline pre-treatment or saline. The responses to intravenous dobutamine (Dob, 1, 5, 10 μg/kg/min.) or saline infusions at 30 and 120 min. after APT induction were evaluated by echocardiography. APT increased mean pulmonary artery pressure and pulmonary vascular resistance index by ∼185%. Doxycycline partially prevented APT-induced pulmonary hypertension (P < 0.05). RV diameter increased in the APT group (from 10.7 ± 0.8 to 18.3 ± 1.6 mm, P < 0.05), but not in the Doxy+APT group (from 13.3 ± 0.9 to 14.4 ± 1.0 mm, P > 0.05). RV dysfunction on stress echocardiography was observed in embolized lambs (APT+Dob group) but not in embolized animals pre-treated with doxycycline (Doxy+APT+Dob). APT increased MMP-9 activity, oxidative stress and gelatinolytic activity in the RV. Although doxycycline had no effects on RV MMP-9 activity, it prevented the increases in RV oxidative stress and gelatinolytic activity (P < 0.05). APT increased serum cardiac troponin I concentrations (P < 0.05), doxycycline partially prevented this alteration (P < 0.05). We found evidence to support that doxycycline prevents RV dysfunction and improves the cardiac responses to dobutamine during APT.