Monitoring of right-sided heart function

Prognostic implication of a novel right ventricular injury score in septic patients

AIMS

We aim to investigate the prognostic value of a right ventricular (RV) injury score based on the concept of RV dilation, RV systolic dysfunction, and RV-pulmonary arterial (PA) decoupling in septic patients and to explore whether the RV injury (RVI) score can be used to grade the severity of RV dysfunction in these patients.

METHODS AND RESULTS

Septic patients admitted to the ICU were prospectively included. We collected haemodynamic and echocardiographic parameters as well as prognostic information. RV dilation was defined as right and left ventricular end-diastolic area ratio (R/LVEDA) > 2/3. RVSD was defined as tricuspid annular plane systolic excursion (TAPSE) < 17 mm, right ventricular fractional area change (FAC) < 35%, or peak velocity of tricuspid annulus via tissue Doppler (S') < 10 cm/s. RV-PA decoupling was represented by the TAPSE/pulmonary arterial systolic pressure (PASP) ratio. RVI score were determined by the presence of the following findings: RVSD, RV dilation, and RV-PA decoupling, that is, one point for each finding. A total of 327 patients were enrolled in this study, among whom 276 survived and 51 died at 30 days after admission. Overall, 18.0% had RV dilation, 35.8% had RVSD, and 21.4% had RV-PA decoupling, with an appreciable overlap present. A multivariate Cox regression analysis showed that RV dilation (HR: 2.19, 95% CI: 1.19-4.01, P = 0.011), RVSD (HR: 2.25, 95% CI: 1.23-4.13, P = 0.009) and RV-PA decoupling (HR: 2.08, 95% CI: 1.19-3.65, P = 0.011) were independently associated with a 30 day mortality. Furthermore, RVI score was also an independent predictor, displayed additive effect with respect to 30 day mortality (RVI score 1 vs. RVI score 0, HR: 2.94, 95% CI: 1.20-7.20, P = 0.018; RVI score 2 vs. RVI score 0, HR: 3.20, 95% CI: 1.28-7.98, P = 0.013; RVI score 3 vs. RVI score 0, HR: 7.17, 95% CI: 2.65-19.38, P < 0.001), and had the best performance in model goodness of fit, discrimination and variance explained than the other RV indices.

CONCLUSIONS

The RVI score was independently related to 30 day mortality and had the potential to grade the severity of RV dysfunction in septic patients.

Perioperative extracorporeal membrane oxygenation in pediatric congenital heart disease: Chinese expert consensus

BACKGROUND

Congenital heart disease (CHD) is one of the main supportive diseases of extracorporeal membrane oxygenation in children. The management of extracorporeal membrane oxygenation (ECMO) for pediatric CHD faces more severe challenges due to the complex anatomical structure of the heart, special pathophysiology, perioperative complications and various concomitant malformations. The survival rate of ECMO for CHD was significantly lower than other classifications of diseases according to the Extracorporeal Life Support Organization database. This expert consensus aims to improve the survival rate and reduce the morbidity of this patient population by standardizing the clinical strategy.

METHODS

The editing group of this consensus gathered 11 well-known experts in pediatric cardiac surgery and ECMO field in China to develop clinical recommendations formulated on the basis of existing evidences and expert opinions.

RESULTS

The primary concern of ECMO management in the perioperative period of CHD are patient selection, cannulation strategy, pump flow/ventilator parameters/vasoactive drug dosage setting, anticoagulation management, residual lesion screening, fluid and wound management and weaning or transition strategy. Prevention and treatment of complications of bleeding, thromboembolism and brain injury are emphatically discussed here. Special conditions of ECMO management related to the cardiovascular anatomy, haemodynamics and the surgical procedures of common complex CHD should be considered.

CONCLUSIONS

The consensus could provide a reference for patient selection, management and risk identification of perioperative ECMO in children with CHD. Video abstract (MP4 104726 kb).

Prevalence and prognostic value of various types of right ventricular dysfunction in mechanically ventilated septic patients

Introduction

Right ventricle (RV) dilation in combination with elevated central venous pressure (CVP), which is a state of RV congestion, is seen as a sign of RV failure (RVF). On the other hand, RV systolic function is usually assessed by tricuspid annular plane systolic excursion (TAPSE) and fractional area change (FAC). This study aimed to investigate the prevalence and prognostic value of RVF and RV systolic dysfunction (RVSD) in septic patients.

Methods

Mechanically ventilated sepsis and septic shock patients were included. We collected haemodynamic and echocardiographic parameters as well as prognostic information including mechanical ventilation duration, length of ICU stay and 30-day mortality. RVF was defined as a right and left ventricular end-diastolic area ratio ≥ 0.6 in combination with CVP ≥ 8 mmHg. RVSD was defined as TAPSE < 16 mm or FAC < 35%.

Results

A total of 215 patients were enrolled in this study, and the patients were divided into 4 groups: patients with normal RV function (normal, n = 101), patients with RVF but without RVSD (RVF only, n = 38), patients with RVSD but without RVF (RVSD only, n = 44), and patients with combined RVF–RVSD (RVF/RVSD, n = 32). The RVF/RVSD group and RVSD only group had a lower cardiac index than the RVF only group and normal groups (p < 0.05). At 30 days after ICU admission, 50.0% of patients had died in the RVF/RVSD group, which was much higher than the mortality in the RVF only group (13.2%) and normal group (13.9%) (p < 0.05). In a Cox regression analysis, the presence of RVF/RVSD was independently associated with 30-day mortality (HR 3.004, 95% CI:1.370–6.587, p = 0.006). In contrast, neither the presence of RVF only nor the presence of RVSD only was associated with 30-day mortality (HR 0.951, 95% CI:0.305–2.960, p = 0.931; HR 1.912, 95% CI:0.853–4.287, p = 0.116, respectively).

Conclusion

The presence of combined RVF–RVSD was associated with 30-day mortality in mechanically ventilated septic patients. Additional studies are needed to confirm and expand this finding.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00902-9.

Advanced echocardiographic phenotyping of critically ill patients with coronavirus-19 sepsis: a prospective cohort study

Background

Sepsis is characterized by various hemodynamic alterations which could happen concomitantly in the heart, pulmonary and systemic circulations. A comprehensive demonstration of their interactions in the clinical setting of COVID-19 sepsis is lacking. This study aimed at evaluating the feasibility, clinical implications, and physiological coherence of the various indices of hemodynamic function and acute myocardial injury (AMI) in COVID-19 sepsis.

Methods

Hemodynamic and echocardiographic data of septic critically ill COVID-19 patients were prospectively recorded. A dozen hemodynamic indices exploring contractility and loading conditions were assessed. Several cardiac biomarkers were measured, and AMI was considered if serum concentration of high-sensitive troponin T (hs-TNT) was above the 99th percentile, upper reference.

Results

Sixty-seven patients were assessed (55 males), with a median age of 61 [50–70] years. Overall, the feasibility of echocardiographic parameters was very good, ranging from 93 to 100%. Hierarchical clustering method identified four coherent clusters involving cardiac preload, left ventricle (LV) contractility, LV afterload, and right ventricle (RV) function. LV contractility indices were not associated with preload indices, but some of them were positively correlated with RV function parameters and negatively correlated with a single LV afterload parameter. In most cases (n = 36, 54%), echocardiography results prompted therapeutic changes. Mortality was not influenced by the echocardiographic variables in multivariable analysis. Cardiac biomarkers’ concentrations were most often increased with high incidence of AMI reaching 72%. hs-TNT was associated with mortality and inversely correlated with most of LV and RV contractility indices.

Conclusions

In this comprehensive hemodynamic evaluation in critically ill COVID-19 septic patients, we identified four homogeneous and coherent clusters with a good feasibility. AMI was common and associated with alteration of LV and RV functions. Echocardiographic assessment had a clinical impact on patient management in most cases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-020-00516-6.

Don't Drive Blind: Driving Pressure to Optimize Ventilator Management in ECMO

Introduction

Driving pressure (DP) while on ECMO has been studied in acute respiratory distress syndrome (ARDS) but no studies exist in those on ECMO without ARDS. We aimed to study association of mortality with DP in all patients on ECMO and compare change in DP before and after initiation of ECMO.

Methods

Consecutive patients placed on ECMO either veno-arterial ECMO or veno-venous ECMO between August 2010 and February 2017 were reviewed. The outcomes were compared based on DP before and after ECMO initiation.

Results

A total of 192 patients were included: 68 (35%) had ARDS while 124 (65%) did not. There were 70 individuals for whom DP was available, 33 (47%) had a decrease in DP, whereas 32 (46%) had an increase in DP and 5 (7%) had no change in DP after ECMO initiation. Those with an increase in DP had a higher initial PEEP (14 vs 9 cm H₂O, p < 0.001) and a higher PEEP decrease after ECMO (6.4 cm H₂O vs by 2.5 cm H₂O, p < 0.001). Those with an increase in DP had a significantly longer stay on ECMO than those without (p = 0.022). On multivariable analysis, higher DP 24 h after ECMO initiation was associated with an increase in 30-day mortality (OR 1.15, 75% CI 1.07–1.24, p ≤ 0.001).

Conclusion

A significant proportion of patients experienced an increase in driving pressure and decrease in compliance after initiation of ECMO. Higher driving pressure after initiation of ECMO is associated with increased adjusted 30-day mortality. Individualized ventilator strategies are needed to reduce mechanical stress while on ECMO.

Physicians' abilities to obtain and interpret focused cardiac ultrasound images from critically ill patients after a 2-day training course

Background

This study aimed to determine whether a focused 2-day cardiac ultrasound training course could enable physicians to obtain and interpret focused cardiac ultrasound (FCU) images from critically ill patients.

Methods

We retrospectively reviewed the FCU images submitted by the physicians who attended a 2-day FCU training courses. Three experienced trainers reviewed the images separately. They determined whether the images were assessable and scored the images on an 8-point scale. They also decided whether the physicians provided correct responses for visual estimations of the left ventricular ejection fraction (LVEF) and right ventricle (RV) dilatation and septal motion.

Results

Among the 327 physicians, 291 obtained images that were considered assessable (89%). The scores for parasternal short-axis view were lower than those obtained for other transthoracic echocardiographic views, p < 0.001. More physicians provided incorrect appraisals of LVEF than of RV dilatation and septal motion (19.9% vs. 3.1%, p < 0.001). The percentages of incorrect answers by LVEF category were as follows: 34.8% on images of LVEF < 30, 24.7% on images of LVEF 30–54, and 16.4% on images of LVEF ≥55%, p < 0.001. A logistic regression analysis showed that patients with abnormal LVEF were associated with physicians’ incorrect assessment of LVEF, with an odds ratio of 1.923 (95% confidence interval (CI):1.071–3.456, p = 0.029).

Conclusions

A large proportion of physicians could obtain and interpret FCU images from critically ill patients after a 2-day training course. However, they still scored low on the parasternal short-axis view and were more likely to make an incorrect assessment of LVEF in patients with abnormal left ventricular systolic function.

Physicians' Ability to Visually Estimate Left Ventricular Ejection Fraction, Right Ventricular Enlargement, and Paradoxical Septal Motion After a 2-Day Focused Cardiac Ultrasound Training Course

OBJECTIVE

Focused cardiac ultrasound (FCU) can provide useful information for the management of shock and acute respiratory distress syndrome. This study aimed to determine whether a 2-day focused cardiac ultrasound training course could enable critical care physicians to interpret ultrasound images in terms of left ventricular ejection fraction (LVEF), ratio of right ventricular end-diastolic area to left ventricular end-diastolic area (R/LVEDA), and septal kinetics.

DESIGN

A prospective analysis of an image test score.

SETTING

Ultrasound training programs in 7 regions across China.

PARTICIPANTS

Two hundred forty-seven critical care physicians.

INTERVENTIONS

All participants received a 2-day FCU training, including 4 sessions of basic heart function appraisal, 3 sessions of hands-on practice, and 1 session of image interpretation.

MEASUREMENTS AND MAIN RESULTS

The post-training total scores were considerably higher than those of pretraining (75.6% v 58.9%, respectively, p < 0.001). After the course, the trainees obtained considerably higher scores on images with LVEF <30% than on images with LVEF 30% to 54% and LVEF ≥55% (100% v 60.0% and 60.0%, respectively, p < 0.001). The trainees obtained considerably higher scores on images with R/LVEDA >1 than on images with R/LVEDA 0.6 to 1 and R/LVEDA <0.6 (90.0% v 80.0% and 80.0%, p = 0.042 and p < 0.001, respectively). The trainees obtained considerably higher scores on images with paradoxical septal movement (PSM) than on images without PSM (100% v 75.0%, respectively, p < 0.001).

CONCLUSION

The physicians' abilities to assess LVEF, RV enlargement, and PSM improved after the training course, and they demonstrated more accurate estimations of the most obviously abnormal images.

Is hemodynamic transesophageal echocardiography needed for patients with left ventricular assist device?

BACKGROUND

Interventions in patients with a left ventricular assist device (LVAD) in the intensive care unit (ICU) are typically performed based on the results of conventional monitoring, such as vital signs and Swan-Ganz catheter (SGC) and LVAD parameters. These variables might not always accurately reflect a patient's cardiac function, volume status, and interventricular septal configuration, however. To assess the accuracy of standard monitoring, we performed routine continuous hemodynamic transesophageal echocardiography (hTEE) to evaluate cardiac function, volume status, and septal position.

METHODS

Between 2011 and 2015, 93 HeartMate II LVADs were implanted. The study group comprised 30 patients with an SGC in place who were monitored routinely by hTEE in the ICU every 1 to 3 hours until extubation. A total of 147 hTEE studies were analyzed retrospectively to observe differences between conventional monitoring and hTEE.

RESULTS

Among the 30 patients studied, 26 (87%) had at least 1 disagreement between conventional monitoring and hTEE findings. In 22 patients (73%), at least 1 of the hTEE studies was abnormal whereas conventional parameters were normal. Abnormal hTEE findings included a shift in the interventricular septum in 19 patients (63%), abnormal ventricular volume status in 22 patients (73%), and right ventricular failure in 9 patients (30%). Based on conventional monitoring, none of the patients required an LVAD speed change, whereas hTEE showed that 14 patients (47%) needed an LVAD speed adjustment.

CONCLUSIONS

Conventional monitoring in the ICU might not provide an accurate representation of cardiac function, ventricular volume status, or septal position in patients with LVAD. Continuous monitoring with hTEE in patients with an LVAD may help guide optimal intervention in the ICU setting during the early postoperative period.

Hemodynamic transesophageal echocardiography after left ventricular assist device implantation

OBJECTIVE

The authors hypothesized that the clinical profile of patients undergoing hTEE after continuous flow left ventricular assist device (CF-LVAD) implant would be in patients with greater acuity, more blood product utilization, and longer length of ICU stay, and that hTEE would change clinical management.

DESIGN

Retrospective review.

SETTING

University hospital.

PARTICIPANTS

One hundred consecutive patients receiving a CF-LVAD.

INTERVENTIONS

Retrospective review using a standardized electronic form of a miniaturized disposable transesophageal echocardiography probe that documented not only physical findings but also changes in hemodynamic management (hTEE) in CF-LVAD patients.

MEASUREMENTS AND MAIN RESULTS

Of the 100 patients, 41 received an hTEE probe. The INTERMACS score, Leitz-Miller Score, and Kormos score indicated the hTEE group had a statistically significant greater risk of morbidity and mortality. Interoperatively, the hTEE group received more blood products and was more likely to have an open chest. Postoperatively, the hTEE group received more blood products, had a longer total length of stay, and had increased mortality. ICU length of stay, days on inotropes and days on mechanical ventilation were not statistically significant between the 2 groups. Information obtained from hTEE changed ICU management in 72% of studies.

CONCLUSION

Retrospective review of CF-LVAD patients revealed that postoperative hTEE is used in sicker CF-LVAD patients and frequently leads to changes in ICU clinical management.

Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Intensive care management of pulmonary hypertension

Pulmonary hypertension (PH) in the Intensive Care Unit (ICU) may be due to preexisting pulmonary vascular lung disease, liver disease, or cardiac diseases. PH also may be caused by critical illnesses, such as acute respiratory distress syndrome (ARDS), acute left ventricular dysfunction and pulmonary embolism, or may occur after cardiac or thoracic surgery.

Regardless of the underlying cause of PH, the final common pathway for hemodynamic deterioration and death is RV failure, which is the most challenging aspect of patient management. Therapy is thus aimed at acutely relieving RV overload by decreasing PVR and reversing RV failure with pulmonary vasodilators and inotropes.

Mechanical ventilation during extracorporeal membrane oxygenation

The timing of extracorporeal membrane oxygenation (ECMO) initiation and its outcome in the management of respiratory and cardiac failure have received considerable attention, but very little attention has been given to mechanical ventilation during ECMO. Mechanical ventilation settings in non-ECMO studies have been shown to have an effect on survival and may also have contributed to a treatment effect in ECMO trials. Protective lung ventilation strategies established for non-ECMO-supported respiratory failure patients may not be optimal for more severe forms of respiratory failure requiring ECMO support. The influence of positive end-expiratory pressure on the reduction of the left ventricular compliance may be a matter of concern for patients receiving ECMO support for cardiac failure. The objectives of this review were to describe potential mechanisms for lung injury during ECMO for respiratory or cardiac failure, to assess the possible benefits from the use of ultra-protective lung ventilation strategies and to review published guidelines and expert opinions available on mechanical ventilation-specific management of patients requiring ECMO, including mode and ventilator settings. Articles were identified through a detailed search of PubMed, Ovid, Cochrane databases and Google Scholar. Additional references were retrieved from the selected studies. Growing evidence suggests that mechanical ventilation settings are important in ECMO patients to minimize further lung damage and improve outcomes. An ultra-protective ventilation strategy may be optimal for mechanical ventilation during ECMO for respiratory failure. The effects of airway pressure on right and left ventricular afterload should be considered during venoarterial ECMO support of cardiac failure. Future studies are needed to better understand the potential impact of invasive mechanical ventilation modes and settings on outcomes.

The evolving concepts of haemodynamic support: from pulmonary artery catheter to echocardiography and theragnostics

Echocardiography is a non-invasive tool, aimed towards the anatomical and functional characterization of the heart. In Intensive Care it is considered nowadays as a necessary tool for patient evaluation. However, the information obtained using echocardiography is not the same as provided by other means, namely the invasive ones. In recent years there has been a significant evolution in the general concepts of haemodynamic support for the critically ill patient. In this new environment, echocardiography has gained particular relevance. In this text the new positioning of echocardiography in the light of the new concepts for hemodynamic support is described, as well as, the need for a specific formative program directed towards Intensive Care physicians. A new generation of biomarkers can also add relevant information and start a new era in haemodynamic support. They may help to further characterize the disease process, identifying patients at risk, as well as, characterize specific organ failure as well as monitoring therapy.

Functional echocardiography in assessment of the cardiovascular system in asphyxiated neonates

Perinatal asphyxia commonly results in multi-organ damage, and cardiovascular dysfunction is a frequent association. Myocardial damage, right ventricular dysfunction, abnormal circulatory transition, and impaired autoregulation may all contribute to postnatal neurological damage. Adequate monitoring and appropriate targeted treatment therefore are essential after an asphyxial insult. Standard methods of cardiovascular monitoring in the neonate have limitations. Point of care ultrasound scanning or functional echocardiography offers extra information to assist the clinician in identifying when there is significant cardiovascular impairment, classifying the underlying abnormal physiology and potentially targeting appropriate therapy, thereby optimizing the post-insult cerebral blood flow and oxygen delivery.

Echocardiography for hemodynamic evaluation in the intensive care unit

The use of echocardiography in the intensive care unit for patients in shock allows the accurate measurement of several hemodynamic variables in a noninvasive way. By using echocardiography as a hemodynamic monitoring tool, the clinician can evaluate several aspects of shock states, such as cardiac output and fluid responsiveness, myocardial contractility, intracavitary pressures, and biventricular interactions. However, to date, there have been few guidelines suggesting an objective hemodynamic-based examination in the intensive care unit, and most intensivists are usually not familiar with this tool. In this review, we describe some of the most important hemodynamic parameters that can be obtained at the bedside with transthoracic echocardiography.

Hemodynamic impact of a positive end-expiratory pressure setting in acute respiratory distress syndrome: importance of the volume status

OBJECTIVE

The hemodynamic impact of positive end-expiratory pressure in acute respiratory distress syndrome and the underlying mechanisms have not been extensively investigated during low stretch ventilation. Our aim was to evaluate the hemodynamic effect of increasing positive end-expiratory pressure when tidal volume and the plateau pressure are limited and to explore the underlying mechanisms.

DESIGN

Prospective study.

SETTING

Medical intensive care unit.

PATIENTS

Twenty-one acute respiratory distress syndrome patients ventilated with a tidal volume of 6.0 +/- 0.5 mL/kg of predicted body weight.

INTERVENTION

Positive end-expiratory pressure was significantly increased from 5 +/- 1 cm H2O to 13 +/- 4 cm H2O for reaching a plateau pressure of 30 +/- 1 cm H2O. At high positive end-expiratory pressure, passive leg raising was performed for increasing the central blood volume.

MEASUREMENTS

We performed echocardiography and pulmonary artery catheterization during positive end-expiratory pressure increase and during passive leg raising at high positive end-expiratory pressure.

MAIN RESULTS

With positive end-expiratory pressure elevation, the cardiac index decreased by 13% +/- 9%. The right ventricular end-diastolic area, right atrial pressure, and pulmonary vascular resistance increased by 13% +/- 20%, 34% +/- 24% and 32% +/- 31%, respectively (p < .01; p = .04; and p < .01 vs. baseline, respectively). The transpulmonary pressure difference (mean pulmonary artery pressure--pulmonary artery occlusion pressure) increased (p < .05). Both at low and high positive end-expiratory pressure, an acute cor pulmonale was observed in the same three (14%) patients. At high positive end-expiratory pressure, the passive leg raising significantly increased the right and left ventricular end-diastolic areas and right atrial pressure. Passive leg raising also decreased the transpulmonary pressure difference (p < .05), increased the cardiac index by 14% +/- 10%, and decreased the pulmonary vascular resistance by 21% +/- 20% (both p < .01 vs. baseline).

CONCLUSIONS

In acute respiratory distress syndrome patients, a positive end-expiratory pressure increase with limited tidal volume and plateau pressure reduced cardiac output by increasing the right ventricular afterload. Passive leg raising restored cardiac output by reducing the transpulmonary pressure difference and the pulmonary vascular resistance. This suggests that some pulmonary microvessels were collapsed by positive end-expiratory pressure elevation and were recruited by increasing the central blood volume.

Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS)

Echocardiography is increasingly used in the management of the critically ill patient as a non-invasive diagnostic and monitoring tool. Whilst in few countries specialized national training schemes for intensive care unit (ICU) echocardiography have been developed, specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice are lacking. Further, existing echocardiography accreditation does not reflect the requirements of the ICU practitioner. The WINFOCUS (World Interactive Network Focused On Critical UltraSound) ECHO-ICU Group drew up a document aimed at providing guidance to individual physicians, trainers and the relevant societies of the requirements for the development of skills in echocardiography in the ICU setting. The document is based on recommendations published by the Royal College of Radiologists, British Society of Echocardiography, European Association of Echocardiography and American Society of Echocardiography, together with international input from established practitioners of ICU echocardiography. The recommendations contained in this document are concerned with theoretical basis of ultrasonography, the practical aspects of building an ICU-based echocardiography service as well as the key components of standard adult TTE and TEE studies to be performed on the ICU. Specific issues regarding echocardiography in different ICU clinical scenarios are then described. Obtaining competence in ICU echocardiography may be achieved in different ways - either through completion of an appropriate fellowship/training scheme, or, where not available, via a staged approach designed to train the practitioner to a level at which they can achieve accreditation. Here, peri-resuscitation focused echocardiography represents the entry level--obtainable through established courses followed by mentored practice. Next, a competence-based modular training programme is proposed: theoretical elements delivered through blended-learning and practical elements acquired in parallel through proctored practice. These all linked with existing national/international echocardiography courses. When completed, it is anticipated that the practitioner will have performed the prerequisite number of studies, and achieved the competency to undertake accreditation (leading to Level 2 competence) via a recognized National or European examination and provide the appropriate required evidence of competency (logbook). Thus, even where appropriate fellowships are not available, with support from the relevant echocardiography bodies, training and subsequently accreditation in ICU echocardiography becomes achievable within the existing framework of current critical care and cardiological practice, and is adaptable to each countrie's needs.

Right ventricular dysfunction

PURPOSE OF REVIEW

Until recently the right ventricle's role in myocardial dynamics has not been fully appreciated. This article provides an overview of the pathophysiology, imaging and management of right ventricular dysfunction.

RECENT FINDINGS

That levosimendan may promote right ventricular function opens new avenues for treatment. In addition there are existing therapies such as phosphodiesterase inhibitors and nitric oxide, which offer yet further modalities to improve outcome in right ventricular failure. How these drugs are used, in combination or alone, in conjunction with ventilatory and cardiovascular strategies has not been evaluated in multicentred randomized controlled trials.

SUMMARY

Acute right ventricular dysfunction is relatively common. There is a lack of convincing evidence in favour of any single treatment modality. Imaging methods now permit a more accurate evaluation of the right ventricle and its function. Combining treatments may offer significant advantages and the imaging and monitoring available allows real-time assessment of the response to intervention. This article illustrates how incomplete our knowledge of this condition and its management within the critical care setting is and reinforces previous calls for suitably designed trials to evaluate and develop guidelines for existing strategies and therapeutic agents.

Heart-lung interactions

PURPOSE OF REVIEW

Assessment of cardiovascular stability using ventilation-induced changes in measured physiological variables, referred to as functional hemodynamic monitoring, usually requires measurement of ventilation-induced changes in venous return. Thus, it is important to understand the determinants of these complex heart-lung interactions.

RECENT FINDINGS

Several animal and human studies have recently documented that ventricular interdependence plays an important role during positive-pressure breathing, causing acute cor pulmonale. With the use of lower tidal volume ventilation in patients with acute respiratory failure, the incidence of acute cor pulmonale is decreasing proportionally. When present, however, it induces a stroke volume variation that is 180 degrees out of phase with that seen in hypovolemic states, such that left ventricular stroke volume increases during inspiration rather than decreasing as seen in hypovolemia. Further, when either tidal volume or positive end-expiratory pressure levels are varied, both stroke volume variation and pulse pressure variation are affected in a predictable manner. The greater the swing in intrathoracic pressure, the greater the change in venous return.

SUMMARY

Functional hemodynamic monitoring is becoming more prevalent. For it to be used effectively, the operator needs to have a solid understanding of how ventilation induces both pulse pressure variation and stroke volume variation in that specific patient.

Management strategies for patients with pulmonary hypertension in the intensive care unit

OBJECTIVE

Pulmonary hypertension may be encountered in the intensive care unit in patients with critical illnesses such as acute respiratory distress syndrome, left ventricular dysfunction, and pulmonary embolism, as well as after cardiothoracic surgery. Pulmonary hypertension also may be encountered in patients with preexisting pulmonary vascular, lung, liver, or cardiac diseases. The intensive care unit management of patients can prove extremely challenging, particularly when they become hemodynamically unstable. The objective of this review is to discuss the pathogenesis and physiology of pulmonary hypertension and the utility of various diagnostic tools, and to provide recommendations regarding the use of vasopressors and pulmonary vasodilators in intensive care.

DATA SOURCES AND EXTRACTION

We undertook a comprehensive review of the literature regarding the management of pulmonary hypertension in the setting of critical illness. We performed a MEDLINE search of articles published from January 1970 to March 2007. Medical subject headings and keywords searched and cross-referenced with each other were: pulmonary hypertension, vasopressor agents, therapeutics, critical illness, intensive care, right ventricular failure, mitral stenosis, prostacyclin, nitric oxide, sildenafil, dopamine, dobutamine, phenylephrine, isoproterenol, and vasopressin. Both human and animal studies related to pulmonary hypertension were reviewed.

CONCLUSIONS

Pulmonary hypertension presents a particular challenge in critically ill patients, because typical therapies such as volume resuscitation and mechanical ventilation may worsen hemodynamics in patients with pulmonary hypertension and right ventricular failure. Patients with decompensated pulmonary hypertension, including those with pulmonary hypertension associated with cardiothoracic surgery, require therapy for right ventricular failure. Very few human studies have addressed the use of vasopressors and pulmonary vasodilators in these patients, but the use of dobutamine, milrinone, inhaled nitric oxide, and intravenous prostacyclin have the greatest support in the literature. Treatment of pulmonary hypertension resulting from critical illness or chronic lung diseases should address the primary cause of hemodynamic deterioration, and pulmonary vasodilators usually are not necessary.

Effects of levosimendan on acute pulmonary embolism-induced right ventricular failure*

OBJECTIVE

Repeated episodes of pulmonary embolism can persistently increase pulmonary arterial pressure and depress right ventricular contractility. We investigated the effects of levosimendan on right ventricular-pulmonary arterial coupling in this model of right ventricular failure.

DESIGN

Prospective, controlled, randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Fourteen anesthetized piglets.

INTERVENTIONS

Repeated acute pulmonary embolisms were induced with autologous blood clots to induce persistent right ventricular failure. Animals were randomly assigned to a control or levosimendan group. Levosimendan 20 microg/kg was administered in 10 mins followed by 0.2 microg/kg/min or same volumes of isotonic saline.

MEASUREMENTS AND MAIN RESULTS

Pulmonary artery distal resistance and proximal elastance by pressure-flow relationships and vascular impedance were measured. We noted right ventricle contractility by the end-systolic pressure-volume relationship (Ees), pulmonary artery effective elastance by the end-diastolic to end-systolic relationship (Ea), and right ventricular-pulmonary arterial coupling efficiency by the Ees/Ea ratio. The gradual pulmonary artery embolism increased pulmonary artery resistance and elastance, increased Ea from 1.01 +/- 0.17 to 5.58 +/- 0.37 mm Hg/mL, decreased Ees from 1.75 +/- 0.12 to 1.29 +/- 0.20 mm Hg/mL, and decreased Ees/Ea from 1.74 +/- 0.20 to 0.24 +/- 0.09. Compared with placebo, levosimendan decreased pulmonary arterial elastance and characteristic impedance. Right ventricular-pulmonary arterial coupling was restored by both an increase in right ventricular contractility and a decrease in right ventricular afterload.

CONCLUSIONS

A gradual increase in pulmonary artery pressure induced by pulmonary embolism persistently worsens pulmonary artery hemodynamics, right ventricular contractility, right ventricular-pulmonary arterial coupling, and cardiac output. Levosimendan restores right ventricular-pulmonary arterial coupling better than placebo, because of combined pulmonary vasodilation and increased right ventricular contractility.

What role does the right side of the heart play in circulation?

Right ventricular failure (RVF) is an underestimated problem in intensive care. This review explores the physiology and pathophysiology of right ventricular function and the pulmonary circulation. When RVF is secondary to an acute increase in afterload, the picture is one of acute cor pulmonale, as occurs in the context of acute respiratory distress syndrome, pulmonary embolism and sepsis. RVF can also be caused by right myocardial dysfunction. Pulmonary arterial catheterization and echocardiography are discussed in terms of their roles in diagnosis and treatment. Treatments include options to reduce right ventricular afterload, specific pulmonary vasodilators and inotropes.

Pericardiotomy and right ventricular failure: a case report

A 57-year-old woman developed cardiogenic shock secondary to right ventricular failure in the postoperative setting. Because of clinical suspicion of pulmonary embolism, the patient was taken to the operating room for emergency thrombectomy. The patient improved dramatically after sternotomy and pericardiotomy, with no evidence of thrombus being found. Sternotomy followed by pericardiotomy may have a role in the treatment of acute right ventricular failure with small pericardial effusion.

Echocardiographic measurement of ventricular function

PURPOSE OF REVIEW

We review new findings concerning ventricular function in patients in intensive care units with shock or unexplained respiratory distress syndrome analyzed using echocardiography.

RECENT FINDINGS

Bedside echocardiography is not only an imaging technique but should be considered as a hemodynamic method. Left-ventricular systolic function can be assessed in daily clinical practice by measuring shortening fraction, fraction area change and ejection fraction. But these indices are dependent on load conditions. Index of myocardial performance can be also used. Rate of left-ventricular pressure increase may be measured from mitral regurgitation. Other indices such a maximal elastance and preload-adjusted maximal power were developed to evaluate myocardial systolic function but are not still used in clinical practice in patients in intensive care. Cardiac output measurement can be calculated easily from aortic annulus diameter and the velocity time integral of aortic blood flow. To complete the assessment of ventricular function, left-ventricular diastolic function and pressure as well as right ventricular size, septal movement and right pressures should be analyzed.

SUMMARY

Using echocardiography the intensivist can examine both the mechanism and the cause of shock or pulmonary edema. It is time to increase the use of this technique in intensive care units.