Acute Right Ventricle Failure in the Intensive Care Unit: Assessment and Management

Instantaneous Right Ventricular to Pulmonary Artery Systolic Pressure Difference in Cardiac Surgery: A Retrospective and Prospective Cohort Study

BACKGROUND

During cardiac surgery, right ventricular outflow tract obstruction (RVOTO) is defined as an instantaneous pressure difference ≥6 mmHg between right ventricular systolic pressure (RVSP) and pulmonary artery systolic pressure (PASP), for ≥5 minutes. Risk factors for RVOTO remain poorly understood. This cohort study is designed to evaluate the incidence, characteristics and outcomes of the patients who experienced RVOTO.

METHODS

Instantaneous pressure difference between RVSP and PASP was measured using a pulmonary artery catheter with a right ventricular port during cardiac surgery from a retrospective (n=295) and a prospective (n=105) cohort.

RESULTS

From the retrospective and prospective cohort, incidence of RVOTO was 30.2 and 36.2% before cardiopulmonary bypass (CPB) initiation and 43.7 and 47.6% after CPB separation. Before CPB initiation, patients with RVOTO had higher cardiac output (4.2±1.5 vs 3.8±1.1L⋅min-1, P=0.033), received more inhaled epoprostenol (79 vs 61%, P=0.005) and inotropes (66 vs 51%, P=0.016) compared to those without RVOTO. After CPB separation, patients with RVOTO had higher heart rate (62±15 vs 58±13 beats⋅min-1, P=0.011), cardiac output (4.1±1.4 vs 3.7±1.1L⋅min-1, P=0.003), CPB duration (90±45 vs 77±30mins, P=0.014), lower fluid balance (758±1123 vs 1063±1089mL, P=0.021) and were more exposed to intratracheal milrinone (12 vs 4%, P=0.015) compared to those without RVOTO. The time with persistent organ dysfunction (TPOD) at 28 days after surgery was similar among patients who had a RVOTO event, before CPB initiation or after CPB separation, compared to those who did not.

CONCLUSION

RVOTO is common in cardiac surgery. However, it is not associated with longer TPOD.

Continuous Right Ventricular Pressure Monitoring in Cardiac Surgery

OBJECTIVE

Right ventricular (RV) dysfunction in cardiac surgery can lead to RV failure, which is associated with increased morbidity and mortality. Abnormal RV function can be identified using RV pressure monitoring. The primary objective of the study is to determine the proportion of patients with abnormal RV early to end-diastole diastolic pressure gradient (RVDPG) and abnormal RV end-diastolic pressure (RVEDP) before initiation and after cardiopulmonary bypass (CPB) separation. The secondary objective is to evaluate if RVDPG before CPB initiation is associated with difficult and complex separation from CPB, RV dysfunction, and failure at the end of cardiac surgery.

DESIGN

Prospective study.

SETTING

Tertiary care cardiac institute.

PARTICIPANTS

Cardiac surgical patients.

INTERVENTION

Cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Automated electronic quantification of RVDPG and RVEDP were obtained. Hemodynamic measurements were correlated with cardiac and extracardiac parameters from transesophageal echocardiography and postoperative complications. Abnormal RVDPG was present in 80% of the patients (n = 105) at baseline, with a mean RVEDP of 14.2 ± 3.9 mmHg. Patients experienced an RVDPG > 4 mmHg for a median duration of 50.2% of the intraoperative period before CPB initiation and 60.6% after CPB separation. A total of 46 (43.8%) patients had difficult/complex separation from CPB, 18 (38.3%) patients had RV dysfunction, and 8 (17%) had RV failure. Abnormal RVDPG before CPB was not associated with postoperative outcome.

CONCLUSION

Elevated RVDPG and RVEDP are common in cardiac surgery. RVDPG and RVEDP before CPB initiation are not associated with RV dysfunction and failure but can be used to diagnose them.

Perioperative management of the vulnerable and failing right ventricle

Under recognition combined with suboptimal management of right ventricular (RV) dysfunction and failure is associated with significant perioperative morbidity and mortality. The contemporary perioperative team must be prepared with an approach for early recognition and prompt treatment. In this review, a consensus-proposed scoring system is described to provide a pragmatic approach for expeditious decision-making for these complex patients with a vulnerable RV. Importantly, this proposed scoring system incorporates the context of the planned surgical intervention. Further, as the operating room (OR) represents a unique environment where patients are susceptible to numerous insults, a practical approach to anesthetic management and monitoring both in the OR and in the intensive care unit is detailed. Lastly, an escalating approach to the management of RV failure and options for mechanical circulatory support is provided.

Complex Heart-Lung Ventilator Emergencies in the CICU

This review aims to enhance the comprehension and management of cardiopulmonary interactions in critically ill patients with cardiovascular disease undergoing mechanical ventilation. Highlighting the significance of maintaining a delicate balance, this article emphasizes the crucial role of adjusting ventilation parameters based on both invasive and noninvasive monitoring. It provides recommendations for the induction and liberation from mechanical ventilation. Special attention is given to the identification of auto-PEEP (positive end-expiratory pressure) and other situations that may impact hemodynamics and patients' outcomes.

Acute heart failure: differential diagnosis and treatment

Acute heart failure is a heterogeneous clinical syndrome and is the first cause of unplanned hospitalization in people >65 years. Patients with heart failure may have different clinical presentations according to clinical history, pre-existing heart disease, and pattern of intravascular congestion. A comprehensive assessment of clinical, echocardiographic, and laboratory data should aid in clinical decision-making and treatment. In some cases, a more accurate evaluation of patient haemodynamics via a pulmonary artery catheter may be necessary to undertake and guide escalation and de-escalation of therapy, especially when clinical, echo, and laboratory data are inconclusive or in the presence of right ventricular dysfunction. Similarly, a pulmonary artery catheter may be useful in patients with cardiogenic shock undergoing mechanical circulatory support. With the subsequent de-escalation of therapy and haemodynamic stabilization, the implementation of guideline-directed medical therapy should be pursued to reduce the risk of subsequent heart failure hospitalization and death, paying particular attention to the recognition and treatment of residual congestion.

Longitudinal Validation of Right Ventricular Pressure Monitoring for the Assessment of Right Ventricular Systolic Dysfunction in a Large Animal Ischemic Model

Right ventricular (RV) dysfunction is a major cause of morbidity and mortality in intensive care and cardiac surgery. Early detection of RV dysfunction may be facilitated by continuous monitoring of RV waveform obtained from a pulmonary artery catheter. The objective is to evaluate the extent to which RV pressure monitoring can detect changes in RV systolic performance assess by RV end-systolic elastance (E_es) following the development of an acute RV ischemic in a porcine model.

HYPOTHESIS

RV pressure monitoring can detect changes in RV systolic performance assess by RV E_es following the development of an acute RV ischemic model.

METHODS AND MODELS

Acute ischemic RV dysfunction was induced by progressive embolization of microsphere in the right coronary artery to mimic RV dysfunction clinically experienced during cardiopulmonary bypass separation caused by air microemboli. RV hemodynamic performance was assessed using RV pressure waveform-derived parameters and RV E_es obtained using a conductance catheter during inferior vena cava occlusions.

RESULTS

Acute ischemia resulted in a significant reduction in RV E_es from 0.26 mm Hg/mL (interquartile range, 0.16-0.32 mm Hg/mL) to 0.14 mm Hg/mL (0.11-0.19 mm Hg/mL; p < 0.010), cardiac output from 6.3 L/min (5.7-7 L/min) to 4.5 (3.9-5.2 L/min; p = 0.007), mean systemic arterial pressure from 72 mm Hg (66-74 mm Hg) to 51 mm Hg (46-56 mm Hg; p < 0.001), and mixed venous oxygen saturation from 65% (57-72%) to 41% (35-45%; p < 0.001). Linear mixed-effect model analysis was used to assess the relationship between E_es and RV pressure-derived parameters. The reduction in RV E_es best correlated with a reduction in RV maximum first derivative of pressure during isovolumetric contraction (dP/dt_max) and single-beat RV E_es. Adjusting RV dP/dt_max for heart rate resulted in an improved surrogate of RV E_es.

INTERPRETATION AND CONCLUSIONS

Stepwise decreases in RV E_es during acute ischemic RV dysfunction were accurately tracked by RV dP/dt_max derived from the RV pressure waveform.

Effects of transthoracic echocardiography on the prognosis of patients with acute respiratory distress syndrome: a propensity score matched analysis of the MIMIC-III database

Background

Acute respiratory distress syndrome (ARDS) has high mortality and is mainly related to the circulatory failure.Therefore, real-time monitoring of cardiac function and structural changes has important clinical significance.Transthoracic echocardiography (TTE) is a simple and noninvasive real-time cardiac examination which is widely used in intensive care unit (ICU) patients.The purpose of this study was to analyze the effect of TTE on the prognosis of ICU patients with ARDS.

Methods

The data of ARDS patients were retrieved from the MIMIC-III v1.4 database and patients were divided into the TTE group and non-TTE group. The baseline data were compared between the two groups. The effect of TTE on the prognosis of ARDS patients was analyzed through multivariate logistic analysis and the propensity score (PS). The primary outcome was the 28-d mortality rate. The secondary outcomes included pulmonary artery catheter (PAC) and Pulse index continuous cardiac output (PiCCO) administration, the ventilator-free and vasopressor-free days and total intravenous infusion volume on days 1, 2 and 3 of the mechanical ventilation. To illuminate the effect of echocardiography on the outcomes of ARDS patients,a sensitivity analysis was conducted by excluding those patients receiving either PiCCO or PAC. We also performed a subgroup analysis to assess the impact of TTE timing on the prognosis of patients with ARDS.

Results

A total of 1,346 ARDS patients were enrolled, including 519 (38.6%) cases in the TTE group and 827 (61.4%) cases in the non-TTE group. In the multivariate logistic regression, the 28-day mortality of patients in the TTE group was greatly improved (OR 0.71, 95%CI 0.55–0.92, P = 0.008). More patients in the TTE group received PAC (2% vs. 10%, P < 0.001) and the length of ICU stay in the TTE group was significantly shorter than that in the non-TTE group (17d vs.14d, P = 0.0001). The infusion volume in the TTE group was significantly less than that of the non-TTE group (6.2L vs.5.5L on day 1, P = 0.0012). Importantly, the patients in the TTE group were weaned ventilators earlier than those in the non-TTE group (ventilator-free days within 28 d: 21 d vs. 19.8 d, respectively, P = 0.071). The Kaplan–Meier survival curves showed that TTE patients had significant lower 28-day mortality than non-TTE patients (log-rank = 0.004). Subgroup analysis showed that TTE after hemodynamic disorders can not improve prognosis (OR 1.02, 95%CI 0.79–1.34, P = 0.844).

Conclusion

TTE was associated with improved 28-day outcomes in patients with ARDS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02028-5.

Cardiac output monitoring - invasive and noninvasive

PURPOSE OF REVIEW

The purpose of this article is to review various contemporary cardiac output (CO) measurement technologies available and their utility in critically ill patients.

RECENT FINDINGS

CO measurement devices can be invasive, minimally invasive, or noninvasive depending upon their method of CO measurement. All devices have pros and cons, with pulmonary artery catheter (PAC) being the gold standard. The invasive techniques are more accurate; however, their invasiveness can cause more complications. The noninvasive devices predict CO via mathematical modeling with several assumptions and are thus prone to errors in clinical situations. Recently, PAC has made a comeback into clinical practice especially in cardiac intensive care units (ICUs). Critical care echocardiography (CCE) is an upcoming tool that not only provides CO but also helps in differential diagnosis. Lack of proper training and nonavailability of equipment are the main hindrances to the wide adoption of CCE.

SUMMARY

PAC thermodilution for CO measurement is still gold standard and most suitable in patients with cardiac pathology and with experienced user. CCE offers an alternative to thermodilution and is suitable for all ICUs; however, structural training is required.

A standardized definition for right ventricular failure in cardiac surgery patients

Right ventricular failure (RVF) is a significant cause of mortality and morbidity after cardiac surgery. Despite its prognostic importance, RVF remains under investigated and without a universally accepted definition in the perioperative setting. We foresee that the provision of a standardized perioperative definition for RVF based on practical and objective criteria will help to improve quality of care through early detection and facilitate the generalization of RVF research to advance this field. This article provides an overview of RVF aetiology, pathophysiology, current diagnostic modalities, as well as a summary of existing RVF definitions. This is followed by our proposal for a standardized definition of perioperative RVF, one that captures RV structural and functional abnormalities through a multimodal approach based on anatomical, echocardiographic, and haemodynamic criteria that are readily available in the perioperative setting (Central Image).

High Versus Normal Blood Pressure Targets in Relation to Right Ventricular Dysfunction After Cardiac Surgery: A Randomized Controlled Trial

OBJECTIVE

Management of right ventricular (RV) dysfunction is challenging. Current practice predominantly is based on data from experimental and small uncontrolled studies and includes augmentation of blood pressure. However, whether such intervention is effective in the clinical setting of cardiac surgery is unknown.

DESIGN

Randomized controlled trial.

SETTING

Single-center study in a tertiary teaching hospital.

PARTICIPANTS

The study comprised 78 patients equipped with a pulmonary artery catheter (PAC), classified according to PAC-derived RV ejection fraction (RVEF); 44 patients had an RVEF of <20%, and 34 patients had an RVEF between ≥20% and <30%.

INTERVENTIONS

Patients randomly were assigned to either a normal target group (mean arterial pressure 65 mmHg) or a high target group [mean arterial pressure 85 mmHg]). The primary end- point was the change in RVEF over a one-hour study period.

MEASUREMENTS AND MAIN RESULTS

There was no significant between-group difference in change of RVEF <20% (-1% [-3.3 to 1.8] in the normal-target group v 0.5% [-1 to 4] in the high-target group; p = 0.159). There was no significant between-group difference in change in RVEF 20%-to-30% (-1% [-3 to 0] in the normal-target group v 1% [-1 to 3] in the high-target group; p = 0.074). These results were in line with the simultaneous observation that echocardiographic variables of RV and left ventricular function also remained unaltered over time, irrespective of either baseline RVEF or treatment protocol.

CONCLUSION

In a mixed cardiac surgery population with RV dysfunction, norepinephrine-mediated high blood pressure targets did not result in an increase in PAC-derived RVEF compared with normal blood pressure targets.

The contemporary pulmonary artery catheter. Part 2: measurements, limitations, and clinical applications

Nowadays, the classical pulmonary artery catheter (PAC) has an almost 50-year-old history of its clinical use for hemodynamic monitoring. In recent years, the PAC evolved from a device that enabled intermittent cardiac output measurements in combination with static pressures to a monitoring tool that provides continuous data on cardiac output, oxygen supply and-demand balance, as well as right ventricular performance. In this review, which consists of two parts, we will introduce the difference between intermittent pulmonary artery thermodilution using bolus injections, and the contemporary PAC enabling continuous measurements by using a thermal filament which heats up the blood. In this second part, we will discuss in detail the measurements of the contemporary PAC, including continuous cardiac output measurement, right ventricular ejection fraction, end-diastolic volume index, and mixed venous oxygen saturation. Limitations of all of these measurements are highlighted as well. We conclude that thorough understanding of measurements obtained from the PAC is the first step in successful application of the PAC in daily clinical practice.

The right ventricle

The healthy right ventricle (RV) has a thin-walled structure compared to the thick-walled left ventricle (LV). It has a complex shape that appears crescentic when viewed in cross section and triangular when viewed from the side.

Physiologically Difficult Airway in the Patient with Severe Hypotension and Metabolic Acidosis

The expertise to recognize and manage the difficult airway is essential in anesthesiology. Conventionally, this refers to anatomical concerns causing difficulties with facemask ventilation and/or with tracheal intubation. Severe derangements in patients' physiology can make induction and intubation likewise difficult, and approximately 30% of critically ill patients had cardiovascular collapse subsequently to intubation. We present the case of a 58-year-old male with a past medical history of type II diabetes and hypertension who presented with altered mental status due to severe metabolic acidosis with a pH of 6.8 on admission to the intensive care unit. The anesthesia team was called to urgently intubate the patient. Upon arrival, the patient was localizing to pain and was hypocapnic, tachycardic, and hypotensive despite ongoing therapy with norepinephrine, vasopressin, and bicarbonate drips. Bedside point-of-care ultrasound showed hyperdynamic left ventricle with no other abnormalities. The patient was induced with IV ketamine, and dissociation occurred with maintenance of spontaneous respirations, which was followed by laryngoscopy and intubation causing only minimal hemodynamic changes. The patient was subsequently dialyzed and treated supportively. He was discharged from the hospital two weeks later—neurologically intact and at his baseline. Combination of hypotension and severe metabolic acidosis is particularly a challenging setting for airway management and a major risk factor for adverse events, including cardiopulmonary arrest. Hemodynamically stable induction agents should be preferred. In addition, sustaining spontaneous ventilation and avoiding periods of apnea in the peri-intubation period is paramount—any buildup of CO₂ could push a critically low pH even lower and cause cardiovascular collapse. Sympathomimetic properties of ketamine make this induction agent a particularly appealing choice in this setting. This case report further supports the concept that severe physiologic perturbations—in which conventional induction techniques are not feasible—should be included in the current definition of a difficult airway.

Resolution of caval syndrome during initial hemodynamic stabilization in dogs with heartworm disease

OBJECTIVE

To report on the spontaneous resolution of caval syndrome in 5 dogs selected for their response to medical stabilization prior to scheduled heartworm extraction.

SERIES SUMMARY

Five dogs with heartworm caval syndrome were treated with sildenafil, fluid, and supplemental oxygen therapy. Moreover, 4 of 5 dogs were also administered pimobendan to achieve hemodynamic stabilization in preparation for percutaneous heartworm extraction. Spontaneous heartworm migration back into the pulmonary arteries was detected from 2 h to 5 days after treatment initiation.

UNIQUE INFORMATION PROVIDED

Unanticipated spontaneous resolution of caval syndrome was documented in a low number of dogs after initiation of a patient stabilization protocol aiming at improving right ventricular hemodynamics and reducing pulmonary artery pressure prior to scheduled heartworm extraction. At this time, it is unknown if intervention to improve the hemodynamic status of the animal prior to heartworm extraction improves procedure outcome, and which factors contributed to the migration of the heartworms back into the pulmonary arteries in these selected cases. Therefore, this approach cannot be recommended in place of current recommendations for treatment of caval syndrome.

Preliminary Experience Using Diastolic Right Ventricular Pressure Gradient Monitoring in Cardiac Surgery

OBJECTIVES

Right ventricular (RV) dysfunction in cardiac surgery is associated with increased mortality and morbidity and difficult separation from cardiopulmonary bypass (DSB). The primary objective of the present study was to describe the prevalence and characteristics of patients with abnormal RV diastolic pressure gradient (PG). The secondary objective was to explore the association among abnormal diastolic PG and DSB, postoperative complications, high central venous pressure (CVP), and high RV end-diastolic pressure (RVEDP).

DESIGN

Retrospective and prospective validation study.

SETTING

Tertiary care cardiac institute.

PARTICIPANTS

Cardiac surgical patients (n=374) from a retrospective analysis (n=259) and a prospective validation group (n=115).

INTERVENTION

RV pressure waveforms were obtained using a pulmonary artery catheter with a pacing port opened at 19 cm distal to the tip of the catheter. Abnormal RV diastolic PG was defined as >4 mmHg. Both elevated RVEDP and high CVP were defined as >16 mmHg.

MEASUREMENTS AND MAIN RESULTS

From the retrospective and validation cohorts, 42.5% and 48% of the patients had abnormal RV diastolic PG before cardiac surgery, respectively. Abnormal RV diastolic PG before cardiac surgery was associated with higher EuroSCORE II (odds ratio 2.29 [1.10-4.80] v 1.62 [1.10-3.04]; p = 0.041), abnormal hepatic venous flow (45% v 29%; p = 0.038), higher body mass index (28.9 [25.5-32.5] v 27.0 [24.9-30.5]; p = 0.022), pulmonary hypertension (48% v 37%; p = 0.005), and more frequent DSB (32% v 19%; p = 0.023). However, RV diastolic PG was not an independent predictor of DSB, whereas RVEDP (odds ratio 1.67 [1.09-2.55]; p = 0.018) was independently associated with DSB. In addition, RV pressure monitoring indices were superior to CVP in predicting DSB.

CONCLUSION

Abnormal RV diastolic PG is common before cardiac surgery and is associated with a higher proportion of known preoperative risk factors. However, an abnormal RV diastolic PG gradient is not an independent predictor of DSB in contrast to RVEDP.

Pulmonary Hypertension in an Oncologic Intensive Care Unit

Pulmonary hypertension (PH) is the condition of elevated pressures in the pulmonary circulation. PH can develop acutely in patients with critical illness such as acute respiratory distress syndrome, sepsis, massive pulmonary embolism, left ventricular dysfunction, or after surgery. In a cancer patient, unique etiologies such as myeloproliferative disorders, tyrosine kinase inhibitors, or tumor emboli may result in PH. Early recognition and treatment of the causative condition may reverse acute PH or return chronic PH to its baseline status. Progression of the disease or its decompensation due to infection, a thromboembolic event, or other triggers can lead to admission to an intensive care unit. Regardless of etiology, the development or worsening of PH may precipitate hypoxemia, hemodynamic instability, or right ventricular failure, which can be challenging to manage or even fatal. In select cases, rapid institution of advanced treatment modalities may be warranted. This chapter reviews the etiology, epidemiology, pathophysiology, clinical features, diagnosis, and prognosis of PH and presents a comprehensive analysis of PH and right heart failure management strategies in the critical care setting. In particular, a unique perspective on oncologically relevant PH is provided.

Medical Optimization and Liberation of Adult Patients From VA-ECMO

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) can be an efficacious cardiopulmonary support for adults as rescue from refractory cardiogenic shock. It is best employed as a bridging strategy to recovery or alternative support rather than sustained, long-term mechanical circulatory support. The purpose of this paper is to discuss strategies to optimize patient management on VA-ECMO and approaches to promote successful separation from support. Rapid medical optimization will assist in reducing the time on VA-ECMO, thereby improving the likelihood of patient salvage. Suitably trained physicians and personnel, guided by structured protocols, can promote excellence in team care and provision of consistent management. Focusing on anticoagulation, careful neurologic monitoring, prevention of leg ischemia, awareness of differential hypoxemia, optimizing mechanical ventilation, identifying and timely intervention for left-ventricular distension (LVD), along with a strategic weaning algorithm, can prevent significant morbidity and mortality. LVD physiology, diagnosis, and risk factors are reviewed. Indications for LV decompression, along with medical and mechanical management options, are elucidated.

Right Heart Function in Critically Ill Patients at Risk for Acute Right Heart Failure: A Description of Right Ventricular-Pulmonary Arterial Coupling, Ejection Fraction and Pulmonary Artery Pulsatility Index

BACKGROUND

The gold standard for right heart function is the assessment of right ventricular-pulmonary arterial coupling defined as the ratio of arterial to end-systolic elastance (Ea/Emax). This study demonstrates the use of the volumetric pulmonary artery (PA) catheter for estimation of Ea/Emax and describes trends of Ea/Emax, right ventricular ejection fraction (RVEF), and pulmonary artery pulsatility index (PAPi) during initial 48hours of resuscitation in the trauma surgical intensive care unit (ICU).

METHODS

Review of prospectively collected data for 32 mechanically ventilated adult trauma and emergency general surgery patients enrolled within 6hours of admission to the ICU. Haemodynamics, recorded every 12hours for 48hours, were compared among survivors and non-survivors to hospital discharge.

RESULTS

Mean age was 49±20 years, 69% were male, and 84% were trauma patients. Estimated Ea/Emax was associated with pulmonary vascular resistance and inversely related to pulmonary arterial capacitance and PA catheter derived RVEF. Seven (7) trauma patients did not survive to hospital discharge. Non-survivors had higher estimated Ea/Emax, suggesting right ventricular-pulmonary arterial uncoupling, with a statistically significant difference at 48hours (2.3±1.7 vs 1.0±0.58, p=0.018). RVEF was significantly lower in non-survivors at study initiation and at 48hours. PAPi did not show a consistent trend.

CONCLUSIONS

Estimation of Ea/Emax using volumetric PA catheter is feasible. Serial assessment of RVEF and Ea/Emax may help in early identification of right heart dysfunction in critically ill mechanically ventilated patients at risk for acute right heart failure.

Right Ventricular Function in Left Heart Disease

Right ventricular (RV) function is an independent prognostic factor for short- and long-term outcomes in cardiac surgical patients. Patients with mitral valve (MV) disease are at increased risk of RV dysfunction before and after MV operations. Yet RV function is not part of criteria for decision making or risk stratification in this setting. The role of MV disease in the development of pulmonary hypertension (PHTN) and the ultimate impact of PHTN on RV function have been well described. Nonetheless, there are other mechanisms by which MV disease and MV surgery affect RV performance. Research suggests that PHTN may not be the most important determinant of RV dysfunction. Both RV dysfunction and PHTN have independent prognostic significance. This review explores the unique anatomic and functional features of the RV and the pathophysiologic and prognostic implications of RV dysfunction in patients with MV disease in the perioperative period.

Feasibility of biventricular 3D transthoracic echocardiography in the critically ill and comparison with conventional parameters

Background

Transthoracic 3D cardiac analysis is enticing in its potential simplicity and wealth of data available. It has been suggested to be accurate vs magnetic resonance imaging in relatively stable patients, but feasibility and agreement with conventional echocardiographic assessment of stroke volume (SV) have not been thoroughly assessed in critically ill patients, who are traditionally harder to image. The objectives of this study were to compare 3D transthoracic volumetric analysis vs Doppler assessment of SV (which is suggested to be accurate in the critically ill) and Simpson’s biplane assessment in a cohort typical of the intensive care unit (ICU), where accurate assessment is important: mechanically ventilated patients with a significant ventilation/perfusion (V/Q) mismatch. We hypothesised that it would be feasible but might lack agreement.

Methods

Patients were imaged within 24 hours of admission. Inclusion criteria were adult patients, V/Q mismatch present (defined as a ratio of arterial oxygen partial pressure to fractional inspired oxygen < 300), and mechanically ventilated with Doppler SV assessment possible. Biventricular echocardiographic volumetric analysis was performed using Siemens SC2000 along with standard Simpson’s biplane and Doppler SV assessment. 3D images were unacceptable if two segments or more were unable to be seen in two volumetric planes. 3D left ventricular (3DLV) and 3D right ventricular (3DRV) analyses were performed with the Tomtec Imaging and Siemens Acuson platforms, respectively.

Results

Ninety-two patients were included (83 in sinus, 9 in atrial fibrillation). 3DLV and 3DRV analyses were feasible in 72% and 55% of patients, respectively; however, they underestimated SV compared with Doppler by 2.6 ml (± 10.4) and 4.1 ml (± 15.4), respectively. Limits of agreement for 2D, 3DLV and 3DRV volumetric analysis techniques were large.

Conclusions

3DLV and 3DRV volumetric analyses appear feasible (obtainable) in the majority of mechanically ventilated ICU patients. Compared with the Doppler method, 3DLV and 3DRV volumetric analyses underestimate SV. The large limits of agreement between the methods also cast doubt on their comparability. Given the scenarios in which SV analysis is required (e.g., assessment of cardiac performance), our study cautions against the use of 3D SV clinically.

Difficult tracheal intubation in critically ill

Background

Endotracheal intubation in critically ill is a high-risk procedure requiring significant expertise in airway handling as well as understanding of pathophysiology of the disease process.

Main body

Critically ill patients are prone for hypotension and hypoxemia in the immediate post-intubation phase due to blunting of compensatory sympathetic response. Preoxygenation without NIV is frequently suboptimal, as alveolar flooding cause loss of alveolar capillary interface in many of these patients. All these factors, along with relative fluid deficit, neuromuscular fatigue and coexistent organ dysfunction lead to physiologically difficult airway. Airway in ICU can be classified as anatomically difficult, physiologically difficult and anatomically as well as physiologically difficult. Though rapid sequence intubation is the recommended method for securing airway in these patients, other methods like delayed sequence intubation awake intubation and double setup approach can be used in specific subgroups. Further research is needed in this field to set guidelines and fine tune airway management for patients with specific organ failure or dysfunction.

Conclusion

Airway in ICU should be managed according to the physiological as well as the anatomical abnormalities.

Diagnostic workup, etiologies and management of acute right ventricle failure : A state-of-the-art paper

INTRODUCTION

This is a state-of-the-art article of the diagnostic process, etiologies and management of acute right ventricular (RV) failure in critically ill patients. It is based on a large review of previously published articles in the field, as well as the expertise of the authors.

RESULTS

The authors propose the ten key points and directions for future research in the field. RV failure (RVF) is frequent in the ICU, magnified by the frequent need for positive pressure ventilation. While no universal definition of RVF is accepted, we propose that RVF may be defined as a state in which the right ventricle is unable to meet the demands for blood flow without excessive use of the Frank-Starling mechanism (i.e. increase in stroke volume associated with increased preload). Both echocardiography and hemodynamic monitoring play a central role in the evaluation of RVF in the ICU. Management of RVF includes treatment of the causes, respiratory optimization and hemodynamic support. The administration of fluids is potentially deleterious and unlikely to lead to improvement in cardiac output in the majority of cases. Vasopressors are needed in the setting of shock to restore the systemic pressure and avoid RV ischemia; inotropic drug or inodilator therapies may also be needed. In the most severe cases, recent mechanical circulatory support devices are proposed to unload the RV and improve organ perfusion CONCLUSION: RV function evaluation is key in the critically-ill patients for hemodynamic management, as fluid optimization, vasopressor strategy and respiratory support. RV failure may be diagnosed by the association of different devices and parameters, while echocardiography is crucial.