[Interest of the brain natriuretic peptide as a marker of acute cor pulmonale in acute respiratory distress syndrome]

Acute cor pulmonale in patients with acute respiratory distress syndrome: A comprehensive review

Acute respiratory distress syndrome (ARDS)-related acute cor pulmonale (ACP) is found in 8%-50% of all patients with ARDS, and is associated with adverse hemodynamic and survival outcomes. ARDS-related ACP is an echocardiographic diagnosis marked by combined right ventricular dilatation and septal dyskinesia, which connote simultaneous diastolic (volume) and systolic (pressure) overload respectively. Risk factors include pneumonia, hypercapnia, hypoxemia, high airway pressures and concomitant pulmonary disease. Current evidence suggests that ARDS-related ACP is amenable to multimodal treatments including ventilator adjustment (aiming for arterial partial pressure of carbon dioxide < 60 mmHg, plateau pressure < 27 cmH₂O, driving pressure < 17 cmH₂O), prone positioning, fluid balance optimization and pharmacotherapy. Further research is required to elucidate the optimal frequency and duration of routine bedside echocardiography screening for ARDS-related ACP, to more clearly delineate the diagnostic role of transthoracic echocardiography relative to transesophageal echocardiography, and to validate current and novel therapies.

Incidence Proportion of Acute Cor Pulmonale in Patients with Acute Respiratory Distress Syndrome Subjected to Lung Protective Ventilation: A Systematic Review and Meta-analysis

INTRODUCTION

Reported incidence of acute cor pulmonale (ACP) in patients with acute respiratory distress syndrome (ARDS) varies from 10% to 84%, despite being subjected to lung protective ventilation according to the current guidelines. The objective of this review is to find pooled cumulative incidence of ACP in patients with ARDS undergoing lung protective ventilation.

MATERIALS AND METHODS

We searched MEDLINE, EMBASE, Cochrane Library, KoreaMed, LILACS, and WHO Clinical Trial Registry. Cross-sectional or cohort studies were included if they reported or provided data that could be used to calculate the incidence proportion of ACP. Inverse variance heterogeneity (IVhet) and random effect model were used for the main outcome and measures.

RESULTS

We included 16 studies encompassing 1661 patients. The cumulative incidence of ACP using IVhet analysis was 23% (95% confidence interval [CI] = 18%-28%) over 3 days of lung protective ventilation. Random effect analysis of 7 studies (1250 patients) revealed pooled odd ratio of mortality of 1.16 (95% CI = 0.80-1.67, P = 0.44) due to ACP.

CONCLUSION

Patients with ARDS have a 23% risk of developing ACP with lung protective ventilation. Findings of this review indicate the need of updating existing guidelines for ventilating ARDS patients to incorporate right ventricle protective strategy.

Use of B-type natriuretic peptide in critically ill patients

B-type natriuretic peptide (BNP) is increasingly used in emergency departments to assess the cause of acute dyspnea and in cardiology to follow treatments and predict outcome. It is increasingly used in the intensive care unit in situations such as respiratory failure (acute pulmonary edema, exacerbation of chronic obstructive pulmonary disease and difficult weaning from ventilator) or when pulmonary embolism is suspected. BNP has also been used to assess alteration of myocardial function in sepsis. Plasma BNP is very high in septic-shock patients (>1000 pg/ml), which is suggested to relate to both myocardial stretch and to an alteration in one of the BNP clearance pathways. Whether BNP at admission or at discharge may predict outcome requires further investigation.

Cardiovascular biomarkers in the ICU

PURPOSE OF REVIEW

Natriuretic peptides are markers of heart failure and/or cardiac dysfunction that provide useful diagnostic and prognostic information in patients with dyspnea and/or respiratory failure in the emergency department. Cardiac troponins (cTn) have markedly simplified the diagnosis of myocardial infarction. In critically ill patients, conditions like coexisting organ dysfunction multiorgan involvement or altered synthesis/clearance may confound interpretation of designated biomarkers, including natriuretic peptides and cTn. This review focuses on recently published articles relating to the use of natriuretic peptides and cTn in critically ill patients.

RECENT FINDINGS

One new study addresses diagnostic utility of B-type natriuretic peptide to distinguish low-pressure pulmonary edema (acute lung injury/acute respiratory distress syndrome) from high-pressure (cardiogenic) pulmonary edema. Other studies highlight the prognostic value of natriuretic peptides either in unselected and general noncardiac ICU patients and reveal an important reason for elevated B-type natriuretic peptide levels in septic shock.Interesting data focusing on diagnostic and prognostic ability of systematic cTn screening measurements in ICU patients became available.

SUMMARY

Recent studies confirm the excellent prognostic value of natriuretic peptide measurements in ICU patients. Diagnostic properties of natriuretic peptide in ICU patients still remain ambiguous and require further evaluation. Systematic screening with cTn reveals more myocardial infarctions and provides important prognostic information.

The use of natriuretic peptides in the intensive care unit

PURPOSE OF REVIEW

B-type natriuretic peptides are quantitative markers of heart failure (and/or cardiac stress) that summarize the extent of systolic and diastolic left ventricular dysfunction, valvular dysfunction, and right ventricular dysfunction. Based on the observation that heart failure is common albeit difficult to diagnose in the ICU, several studies have begun to evaluate the potential use of B-type natriuretic peptides in various ICU settings.

RECENT FINDINGS

Previous pilot studies have examined the use of B-type natriuretic peptide in the differential diagnosis of hypoxemic respiratory failure, to differentiate cardiogenic from noncardiogenic shocks or to predict fluid responsiveness, to assess myocardial dysfunction and prognosis in patients with severe sepsis, and to predict ventilatory weaning failure.

SUMMARY

Although previous studies were small, they highlight the potential of using B-type natriuretic peptides as a noninvasive easily available tool to quantify cardiac stress.

Nesiritide for the treatment of pulmonary hypertension and cor pulmonale in an infant

Nesiritide is a synthetic form of B-type natriuretic peptide. It is approved for the treatment of acute exacerbations of congestive heart failure in hospitalized adult patients. It is currently under investigation for use in other settings and other patient populations. This article describes administration of nesiritide to an infant patient with severe pulmonary hypertension and cor pulmonale. No adverse reactions occurred during administration of the drug. Specifically, there was no hypertension, vomiting, arrhythmia, or changes in renal function. No changes in renal function occurred in the months subsequent to treatment. This case report illustrates that nesiritide can be safely administered to critically ill infants with pulmonary hypertension and cor pulmonale. Our patient experienced a decrease in pulmonary pressure and improved clinical condition during and after the infusion. However, further study is required to fully evaluate the safety and efficacy of nesiritide for these patients.