Perioperative echocardiographic strain analysis: what anesthesiologists should know.

PURPOSE: Echocardiographic strain analysis by speckle tracking allows assessment of myocardial deformation during the cardiac cycle. Its clinical applications have significantly expanded over the last two decades as a sensitive marker of myocardial dysfunction with important diagnostic and prognostic values. Strain analysis has the potential to become a routine part of the perioperative echocardiographic examination for most anesthesiologist-echocardiographers but its exact role in the perioperative setting is still being defined. CLINICAL FEATURES: This clinical report reviews the principles underlying strain analysis and describes its main clinical uses pertinent to the field of anesthesiology and perioperative medicine. Strain for assessment of left and right ventricular function as well as atrial strain is described. We also discuss the potential role of strain to aid in perioperative risk stratification, surgical patient selection in cardiac surgery, and guidance of anesthetic monitor choice and clinical decision-making in the perioperative period. CONCLUSION: Echocardiographic strain analysis is a powerful tool that allows seeing what conventional 2D imaging sometimes fails to reveal. It often provides pathophysiologic insight into various cardiac diseases at an early stage. Strain analysis is readily feasible and reproducible thanks to the use of highly automated software platforms. This technique shows promising potential to become a valuable tool in the arsenal of the anesthesiologist-echocardiographer and aid in perioperative risk-stratification and clinical decision-making.

RéSUMé: OBJECTIF: L'analyse échocardiographique de la déformation cardiaque (strain analysis) par suivi des marqueurs acoustiques (speckle-tracking) permet d'évaluer la déformation du myocarde au cours du cycle cardiaque. Ses applications cliniques se sont considérablement développées au cours des deux dernières décennies en tant que marqueur sensible du dysfonctionnement myocardique, avec des valeurs diagnostiques et pronostiques importantes. L'analyse de la déformation cardiaque a le potentiel de devenir une partie intégrante de l'examen échocardiographique périopératoire de routine pour la plupart des anesthésiologistes-échocardiographes, mais son rôle exact dans le cadre périopératoire est encore en cours de définition. CARACTéRISTIQUES CLINIQUES: Ce rapport clinique passe en revue les principes qui sous-tendent l'analyse de la déformation cardiaque et décrit ses principales utilisations cliniques pertinentes dans le domaine de l'anesthésiologie et de la médecine périopératoire. L'analyse de la déformation cardique pour l'évaluation de la fonction ventriculaire gauche et droite ainsi que de la déformation auriculaire sont décrites. Nous discutons également du rôle potentiel de l'analyse de la déformation cardiaque pour aider à la stratification du risque périopératoire, à la sélection des patients en chirurgie cardiaque, à l'orientation du choix des moniteurs anesthésiques, et à la prise de décision clinique en période périopératoire. CONCLUSION: L'analyse échocardiographique de la déformation cardiaque est un outil puissant qui permet de voir ce que l'imagerie 2D conventionnelle ne parvient parfois pas à révéler. Elle fournit souvent un aperçu physiopathologique de diverses maladies cardiaques à un stade précoce. L'analyse de la déformation cardiaque est facilement réalisable et reproductible grâce à l'utilisation de plateformes logicielles hautement automatisées. Cette technique est potentiellement prometteuse et pourrait devenir un outil précieux dans l'arsenal de l'anesthésiologiste-échocardiographe et aider à la stratification du risque périopératoire et à la prise de décision clinique.

Prospective Study of Ultrasound Markers of Organ Congestion in Critically Ill Patients With Acute Kidney Injury.

Introduction: Organ congestion may be a mediator of adverse outcomes in critically ill patients with severe acute kidney injury (AKI). The presence of abnormal venous Doppler waveforms could identify patients with clinically significant organ congestion who may benefit from a decongestive strategy. Methods: This prospective multicenter cohort study enrolled patients with severe AKI defined as Kidney Disease: Improving Global Outcomes stage 2 or higher. Patients were not eligible if they received renal replacement therapy (RRT) for more than 72 hours at the time of screening. Participants underwent serial Doppler ultrasound examinations of the portal, hepatic and intrarenal veins during the week following enrolment. We calculated the venous excess ultrasound (VExUS) score based on these data. The primary outcome studied was major adverse kidney events at 30 days (MAKE30) defined as death, RRT dependence, or a persistent decrease in kidney function. Results: A total of 125 patients were included for whom 291 ultrasound assessments were performed. Severely abnormal venous waveforms were documented in 14.4% of portal vein assessments, 6.5% of intrarenal venous assessments, and 14.4% of hepatic vein assessments. The individual ultrasound markers were not associated with MAKE30. The VExUS score (grade 0-1: reference; grade 2: adjusted hazard ratio [aHR]: 4.03, confidence interval [CI]: 1.81-8.99; grade 3: aHR: 2.70, CI: 1.10-6.65; P = 0.03), as well as severely abnormal portal, hepatic and intrarenal vein Doppler were each independently associated with mortality. Conclusion: Although not significantly associated with MAKE30, venous Doppler abnormalities suggestive of venous congestion were associated with higher mortality in critically ill patients with severe AKI.

Clinical relevance of transcranial Doppler in a cardiac surgery setting: embolic load predicts difficult separation from cardiopulmonary bypass.

BACKGROUND: During cardiac surgery, transcranial Doppler (TCD) represents a non-invasive modality that allows measurement of red blood cell flow velocities in the cerebral arteries. TCD can also be used to detect and monitor embolic material in the cerebral circulation. Detection of microemboli is reported as a high intensity transient signal (HITS). The importance of cerebral microemboli during cardiac surgery has been linked to the increased incidence of postoperative renal failure, right ventricular dysfunction, and hemodynamic instability. The objective of this study is to determine whether the embolic load is associated with hemodynamic instability during cardiopulmonary bypass (CPB) separation and postoperative complications. METHODS: A retrospective single-centre cohort study of 354 patients undergoing cardiac surgery between December 2015 and March 2020 was conducted. Patients were divided in tertiles, where 117 patients had a low quantity of embolic material (LEM), 119 patients have a medium quantity of microemboli (MEM) and 118 patients who have a high quantity of embolic material (HEM). The primary endpoint was a difficult CPB separation. Multivariate logistic regression was used to determine the potential association between a difficult CPB separation and the number of embolic materials. RESULTS: Patients who had a difficult CPB separation had more HITS compared to patients who had a successful CPB separation (p < 0.001). In the multivariate analysis, patients with MEM decreased their odds of having a difficult CPB weaning compared to patients in the HEM group (OR = 0.253, CI 0.111-0.593; p = 0.001). In the postoperative period patients in the HEM group have a higher Time of Persistent Organ Dysfunction (TPOD), a longer stay in the ICU, a longer duration under vasopressor drugs and a higher mortality rate compared to those in the MEM and LEM groups. CONCLUSION: The result of this study suggests that a high quantity of cerebral embolic material increases the odds of having a difficult CPB separation. Also, it seems to be associated to more complex surgery, a longer CPB time, a higher TPOD and a longer stay in the ICU. Six out of eight patients who died in this cohort were in the HEM group.

Higher portal venous pulsatility is associated with worse clinical outcomes following congenital heart surgery: a single-centre prospective cohort study.

PURPOSE: Increased portal venous flow pulsatility is associated with major complications after adult cardiac surgery. Nevertheless, no data are available for pediatric patients with congenital heart disease. We hypothesized that Doppler parameters including portal flow pulsatility could be associated with postoperative outcomes in children undergoing various cardiac surgeries. METHODS: We conducted a prospective observational cohort study in children undergoing congenital cardiac surgery. We obtained postoperative portal, splenic, and hepatic venous Doppler data and perioperative clinical data including major postoperative complications. Portal and splenic venous flow pulsatility were calculated. We evaluated the association between venous Doppler parameters and adverse outcomes. The primary objective was to determine whether postoperative portal flow pulsatility could indicate major complications following congenital heart surgery. RESULTS: In this study, we enrolled 389 children, 74 of whom experienced major postoperative complications. The mean (standard deviation) portal pulsatility (44 [30]% vs 25 [14]%; 95% confidence interval [CI] for mean difference, 12 to 26; P < 0.001] and splenic pulsatility indices (41 [30]% vs 26 [16]%; 95% CI, 7 to 23; P < 0.001) were significantly higher in children with postoperative complications than in those without complications. The portal pulsatility index was able to help identify postoperative complications in biventricular patients and univentricular patients receiving bidirectional cavopulmonary shunt whereas it did not in other univentricular patients. An increased postoperative portal pulsatility index was significantly associated with major complications after pediatric cardiac surgery (odds ratio, 1.40; 95% CI, 1.29 to 1.91; P < 0.001). CONCLUSIONS: Higher portal venous pulsatility is associated with major postoperative complications in children undergoing cardiac surgery. Nevertheless, more data are needed to conclude the efficacy of portal venous pulsatility in patients with univentricular physiology. STUDY REGISTRATION: ClinicalTrials.gov (NCT03990779); registered 19 June 2019.

RéSUMé: OBJECTIF: L'augmentation de la pulsatilité du flux de la veine porte est associée à des complications majeures après une chirurgie cardiaque chez l'adulte. Néanmoins, aucune donnée n'est disponible pour la patientèle pédiatrique atteinte de cardiopathie congénitale. Nous avons émis l'hypothèse que les paramètres Doppler, y compris la pulsatilité du flux de la veine porte, pourraient être associés aux devenirs postopératoires des enfants bénéficiant de diverses chirurgies cardiaques. MéTHODE: Nous avons réalisé une étude de cohorte observationnelle prospective portant sur des enfants bénéficiant d'une chirurgie cardiaque congénitale. Nous avons obtenu des données Doppler des veines porte, spléniques et hépatiques postopératoires ainsi que des données cliniques périopératoires, y compris les complications postopératoires majeures. La pulsatilité du flux des veines porte et spléniques a été calculée. Nous avons évalué l'association entre les paramètres Doppler veineux et les issues indésirables. L'objectif principal était de déterminer si la pulsatilité du flux postopératoire de la veine porte pouvait constituer un indicateur des complications majeures après une chirurgie cardiaque congénitale. RéSULTATS: Dans cette étude, nous avons recruté 389 enfants, dont 74 ont présenté des complications postopératoires majeures. La pulsatilité moyenne de la veine porte (écart type) (44 [30] % vs 25 [14] %; intervalle de confiance [IC] à 95 % pour la différence moyenne, 12 à 26; P < 0,001] et les indices de pulsatilité splénique (41 [30] % vs 26 [16] %; IC 95 %, 7 à 23; P < 0,001) étaient significativement plus élevés chez les enfants présentant des complications postopératoires que chez les enfants sans complications. L'indice de pulsatilité de la veine porte a permis d'identifier les complications postopératoires chez les patient·es biventriculaires et les patient·es univentriculaires recevant une anastomose cavo-pulmonaire bidirectionnelle (procédure de Glenn), alors que ce n'était pas le cas chez les autres patient·es univentriculaires. Une augmentation postopératoire de l'indice de pulsatilité de la veine porte était significativement associée à des complications majeures après une chirurgie cardiaque pédiatrique (rapport de cotes, 1,40; IC 95 %, 1,29 à 1,91; P < 0,001). CONCLUSION: Une pulsatilité plus élevée de la veine porte est associée à des complications postopératoires majeures chez les enfants bénéficiant d'une chirurgie cardiaque. Néanmoins, davantage de données sont nécessaires pour conclure à l'efficacité de la pulsatilité de la veine porte chez les patient·es présentant une physiologie univentriculaire. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT03990779); enregistrée le 19 juin 2019.

Doppler identified venous congestion in septic shock: protocol for an international, multi-centre prospective cohort study (Andromeda-VEXUS).

INTRODUCTION: Venous congestion is a pathophysiological state where high venous pressures cause organ oedema and dysfunction. Venous congestion is associated with worse outcomes, particularly acute kidney injury (AKI), for critically ill patients. Venous congestion can be measured by Doppler ultrasound at the bedside through interrogation of the inferior vena cava (IVC), hepatic vein (HV), portal vein (PV) and intrarenal veins (IRV). The objective of this study is to quantify the association between Doppler identified venous congestion and the need for renal replacement therapy (RRT) or death for patients with septic shock. METHODS AND ANALYSIS: This study is a prespecified substudy of the ANDROMEDA-SHOCK 2 (AS-2) randomised control trial (RCT) assessing haemodynamic resuscitation in septic shock and will enrol at least 350 patients across multiple sites. We will include adult patients within 4 hours of fulfilling septic shock definition according to Sepsis-3 consensus conference. Using Doppler ultrasound, physicians will interrogate the IVC, HV, PV and IRV 6-12 hours after randomisation. Study investigators will provide web-based educational sessions to ultrasound operators and adjudicate image acquisition and interpretation. The primary outcome will be RRT or death within 28 days of septic shock. We will assess the hazard of RRT or death as a function of venous congestion using a Cox proportional hazards model. Sub-distribution HRs will describe the hazard of RRT given the competing risk of death. ETHICS AND DISSEMINATION: We obtained ethics approval for the AS-2 RCT, including this observational substudy, from local ethics boards at all participating sites. We will report the findings of this study through open-access publication, presentation at international conferences, a coordinated dissemination strategy by investigators through social media, and an open-access workshop series in multiple languages. TRIAL REGISTRATION NUMBER: NCT05057611.

Prolonged cardiovascular pharmacological support and fluid management after cardiac surgery.

OBJECTIVE: To identify potentially modifiable risk factors related to prolonged cardiovascular pharmacological support after weaning from cardiopulmonary bypass (CPB). METHODS: This is a secondary analysis of two prospective cohort study in a specialized cardiac surgery institution in adult patients undergoing cardiac surgery with the use of CPB between August 2016 and July 2017. Prolonged cardiovascular pharmacological support was defined by the need for at least one vasopressor or one inotropic agent 24 hours after separation from CPB. Risk factors were identified among baseline characteristics and peri-operative events through multivariable logistic regression. RESULTS: A total of 247 patients were included and 98 (39.7%) developed prolonged pharmacological support. In multivariable analysis, left ventricular ejection fraction ≤ 30% (OR 9.52, 95% confidence interval (CI) 1.14; 79.25), elevated systolic pulmonary artery pressure (sPAP) > 30 and ≤ 55 mmHg (moderate) (OR 2.52, CI 1.15; 5.52) and sPAP > 55 mmHg (severe) (OR 8.12, CI 2.54; 26.03), as well as cumulative fluid balance in the first 24 hours after surgery (OR 1.76, CI 1.32; 2.33) were independently associated with the development of prolonged pharmacological support. CONCLUSIONS: Prolonged cardiovascular pharmacological support is frequent after cardiac surgery on CPB. Severe LV systolic dysfunction, preoperative pulmonary hypertension and postoperative fluid overload are risk factors. Further studies are required to explore if those risk factors could be modified or not.

Assessment of fluid responsiveness in children using respiratory variations in descending aortic flow.

BACKGROUND: The primary aim of the current study was to investigate the ability of respiratory variations in descending aortic flow, measured with two-dimensional echo at the suprasternal notch (ΔVpeak dAo), to predict fluid responsiveness in anesthetized mechanically ventilated children. In addition, variations in peak descending aortic flow measured with apical transthoracic echo (ΔVpeak LVOT) were examined for the same properties. METHODS: Twenty-seven patients under general anesthesia were investigated in this prospective observational study. Cardiac output, ΔVpeak dAo, and ΔVpeak LVOT were measured at stable conditions after anesthesia induction. The measurements were repeated after a 10 mL kg-1 fluid bolus. Patients were classified as responders if stroke volume index increased by >15% after fluid bolus. The ability of each parameter to predict fluid responsiveness was assessed using receiver operating characteristic curves. RESULTS: Twenty-seven patients were analyzed, mean age and weight 43 months and 16 kg, respectively. Twelve responders and 15 non-responders were identified. ΔVpeak dAo was significantly higher in the responder group (14%, 95% confidence interval [CI]: 12%-17%) compared to the non-responder group (11%, 95% CI: 9%-13%) (p = .04) at baseline. Area under the ROC curve for ΔVpeak dAo and ΔVpeak LVOT was 0.73 (95% CI: 0.52-0.89, p = .02) and 0.56 (0.34-0.78, p = .3), respectively. A baseline level of ΔVpeak dAo of >14% predicted fluid responsiveness with a sensitivity of 58% (95% CI: 28%-85%) and specificity of 73% (95% CI: 45%-92%). CONCLUSION: In mechanically ventilated children, ΔVpeak dAo identified fluid responders with moderate diagnostic power in the current study. ΔVpeak LVOT failed to predict fluid responders in the current study.

Evaluation of Portal, Splenic, and Hepatic Vein Flows in Children Undergoing Congenital Heart Surgery.

OBJECTIVE: Little is known about changes in portal, splenic, and hepatic vein flow patterns in children undergoing congenital heart surgery. This study aimed to determine the characteristics of portal, splenic, and hepatic vein flow patterns using ultrasonography in children undergoing cardiac surgery. DESIGN: Single-center, prospective observational study. SETTING: Tertiary children's hospital, operating room. PARTICIPANTS: Children undergoing cardiac surgery. MEASUREMENT AND MAIN RESULTS: The authors obtained ultrasound data from the heart, inferior vena cava, portal, splenic, and hepatic veins before and after surgeries. In the biventricular group, which included children with atrial and ventricular septal defects and pulmonary stenosis (n = 246), the portal pulsatility index decreased from 38.7% to 25.6% (p < 0.001) after surgery. The preoperative portal pulsatility index was significantly higher in patients with pulmonary hypertension (43.3% v 27.4%; p < 0.001). In the single-ventricle group (n = 77), maximum portal vein flow velocities of Fontan patients were significantly lower (13.5 cm/s) compared with that of patients with modified Blalock-Taussig shunt (19.7 cm/s; p = 0.035) or bidirectional cavopulmonary shunt (23.1 cm/s; p < 0.001). The cardiac index was inversely correlated with the portal pulsatility index in the bidirectional cavopulmonary shunt and Fontan circulation. (ß = -5.693, r2 = 0.473; p = 0.001) The portal pulsatility index was correlated with splenic venous pulsatility and hepatic venous atrial reverse flow velocity in biventricular and single-ventricle groups. CONCLUSIONS: The characteristics of venous Doppler patterns in the portal, splenic, and hepatic veins differed according to congenital heart disease. Further studies are required to determine the association between splanchnic venous Doppler findings and clinical outcomes in this population.

Inhaled milrinone in cardiac surgical patients: pharmacokinetic and pharmacodynamic exploration.

Mean arterial pressure to mean pulmonary arterial pressure ratio (mAP/mPAP) has been identified as a strong predictor of perioperative complications in cardiac surgery. We therefore investigated the pharmacokinetic/pharmacodynamic (PK/PD) relationship of inhaled milrinone in these patients using this ratio (R) as a PD marker. Following approval by the ethics and research committee and informed consent, we performed the following experiment. Before initiation of cardiopulmonary bypass in 28 pulmonary hypertensive patients scheduled for cardiac surgery, milrinone (5 mg) was nebulized, plasma concentrations measured (up to 10 h) and compartmental PK analysis carried out. Baseline (R0) and peak (Rmax) ratios as well as magnitude of peak response (∆Rmax-R0) were measured. During inhalation, individual area under effect-time (AUEC) and plasma concentration-time (AUC) curves were correlated. Potential relationships between PD markers and difficult separation from bypass (DSB) were explored. In this study, we observed that milrinone peak concentrations (41-189 ng ml-1) and ΔRmax-R0 (- 0.12-1.5) were obtained at the end of inhalation (10-30 min). Mean PK parameters agreed with intravenous milrinone published data after correction for the estimated inhaled dose. Paired comparisons yielded a statistically significant increase between R0 and Rmax (mean difference, 0.58: 95% CI 0.43-0.73; P < 0.001). Individual AUEC correlated with AUC (r = 0.3890, r2 = 0.1513; P = 0.045); significance increased after exclusion of non-responders (r = 4787, r2 = 0.2292; P = 0.024). Individual AUEC correlated with ∆Rmax-R0 (r = 5973, r2 = 0.3568; P = 0.001). Both ∆Rmax-R0 (P = 0.009) and CPB duration (P < 0.001) were identified as predictors of DSB. In conclusion, both magnitude of peak response of the mAP/mPAP ratio and CPB duration were associated with DSB.

Fluid Management for Critically Ill Patients with Acute Kidney Injury Receiving Kidney Replacement Therapy: An International Survey.

BACKGROUND: In critically ill patients receiving KRT, high ultrafiltration rates and persistent fluid accumulation are associated with adverse outcomes. The purpose of this international survey was to evaluate current practices and evidence gaps related to fluid removal with KRT in critically ill patients. METHODS: This was a multinational, web-based survey distributed by seven networks comprising nephrologists and intensivists. Physicians involved in the care of critically ill patients were invited to complete a 39-question survey about fluid management practices on KRT. The survey was distributed from September 2021 to December 2021. RESULTS: There were 757 respondents from 96 countries (response rate of 65%). Most respondents practiced adult medicine (89%) and worked in an academic center (69%). The majority (91%) reported aiming for a 0.5- to 2-L negative fluid balance per day when fluid removal is indicated, although there was important variability in what respondents considered a safe maximal target. Intensivists were more likely than nephrologists to use adjunct volume status assessment methods ( i.e. , ultrasound, hemodynamic markers, and intra-abdominal pressure), while nephrologists were more likely to deploy cointerventions aimed at improving tolerance to fluid removal ( i.e. , osmotic agents and low-temperature dialysate). There was a broad consensus that rapid decongestion should be prioritized when fluid accumulation is present, but the prevention of hypotension was also reported as a competing priority. A majority (77%) agreed that performing trials that compare fluid management strategies would be ethical and clinically relevant. CONCLUSIONS: We have identified multiple areas of variability in current practice of fluid management for patients receiving KRT. Most nephrologists and intensivists agreed that several knowledge gaps related to fluid removal strategies should be investigated in future randomized controlled trials.

Hemodynamic management during off-pump coronary artery bypass surgery: a narrative review of proper targets for safe execution and troubleshooting.

Off-pump coronary surgery requires mechanical cardiac displacement, which results in bi-ventricular systolic and diastolic dysfunction. Although transient, subsequent hemodynamic deterioration can be associated with poor prognosis and, in extreme cases, emergency conversion to on-pump surgery, which is associated with high morbidity and mortality. Thus, appropriate decision-making regarding whether the surgery can be proceeded based on objective hemodynamic targets is essential before coronary arteriotomy. For adequate hemodynamic management, avoiding myocardial oxygen supply-demand imbalance, which includes maintaining mean arterial pressure above 70 mmHg and preventing an increase in oxygen demand beyond the patient's coronary reserve, must be prioritized. Maintaining mixed venous oxygen saturation above 60%, which reflects the lower limit of adequate global oxygen supply-demand balance, is also essential. Above all, severe mechanical cardiac displacement incurring compressive syndromes, which cannot be overcome by adjusting major determinants of cardiac output, should be avoided. An uncompromising form of cardiac constraint can be ruled out as long as the central venous pressure is not equal to or greater than the pulmonary artery diastolic (or occlusion) pressure, as this would reflect tamponade physiology. In addition, transesophageal echocardiography should be conducted to rule out mechanical cardiac displacement-induced ventricular interdependence, dyskinesia, severe mitral regurgitation, and left ventricular outflow tract obstruction with or without systolic motion of the anterior leaflet of the mitral valve, which cannot be tolerated during grafting. Finally, the ascending aorta should be carefully inspected for gas bubbles to prevent hemodynamic collapse caused by a massive gas embolism obstructing the right coronary ostium.

Transesophageal Echocardiography in Patients in Cardiac Arrest: The Heart and Beyond.

Point of care ultrasound involves different ultrasound modalities and is useful to assist management in emergent clinical situations such as cardiac arrest. The use of point of care ultrasound in cardiac arrest has mainly been described using transthoracic echocardiography as a diagnostic and as a prognostic tool. However, cardiac evaluation using transthoracic echocardiography might be challenging because of patient-related or technical factors. Furthermore, its use during pulse check pauses has been associated with delays in chest compression resumption. Transesophageal echocardiography (TEE) overcomes these limitations by providing reliable and continuous imaging of the heart without interfering with cardiopulmonary resuscitation. In this narrative review we describe the role of TEE during cardiopulmonary resuscitation in 4 different applications: (1) chest compression quality feedback; (2) rhythm characterization; (3) diagnosis of reversible causes; and (4) procedural guidance. Considering its limitations, we propose an algorithm for the integration of TEE in patients with cardiac arrest with a focus on these 4 applications and extend its use to extracardiac applications.

New Developments in Continuous Hemodynamic Monitoring of the Critically Ill Patient.

Hemodynamic monitoring is a cornerstone in the assessment of patients with circulatory shock. Timely recognition of hemodynamic compromise and proper optimisation is essential to ensure adequate tissue perfusion and maintain renal, hepatic, abdominal, and cerebral functions. Hemodynamic monitoring has significantly evolved since the first inception of the pulmonary artery catheter more than 50 years ago. Bedside echocardiography, when combined with noninvasive and minimally invasive technologies, provides tools to monitor and quantify the cardiac output to promptly react and improve hemodynamic management in an acute care setting. Commonly used technologies include noninvasive pulse-wave analysis, pulse-wave transit time, thoracic bioimpedance and bioreactance, esophageal Doppler, minimally invasive pulse-wave analysis, transpulmonary thermodilution, and pulmonary artery catheter. These monitoring strategies are reviewed here, along with detailed analysis of their operating mode, particularities, and limitations. The use of artificial intelligence to enhance performance and effectiveness of hemodynamic monitoring is reviewed to apprehend future possibilities.

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 (Ees) 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 Ees 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 Ees obtained using a conductance catheter during inferior vena cava occlusions. RESULTS: Acute ischemia resulted in a significant reduction in RV Ees 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 Ees and RV pressure-derived parameters. The reduction in RV Ees best correlated with a reduction in RV maximum first derivative of pressure during isovolumetric contraction (dP/dtmax) and single-beat RV Ees. Adjusting RV dP/dtmax for heart rate resulted in an improved surrogate of RV Ees. INTERPRETATION AND CONCLUSIONS: Stepwise decreases in RV Ees during acute ischemic RV dysfunction were accurately tracked by RV dP/dtmax derived from the RV pressure waveform.

Inhaled Epoprostenol and Milrinone Effect on Right Ventricular Pressure Waveform Monitoring.

BACKGROUND: Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are major complications in cardiac surgery. This study aimed to evaluate the change in RV pressure waveform in patients receiving a combination of inhaled epoprostenol and inhaled milrinone (iE&iM) before cardiopulmonary bypass (CPB) and to assess the safety of this approach with a matched case-control group. METHODS: A prospective single-centre cohort study of adult patients undergoing cardiac surgery administered iE&iM through an ultrasonic mesh nebulizer. RV pressure waveform monitoring was obtained by continuously transducing the RV port of the pulmonary artery (PA) catheter. RESULTS: The final analysis included 26 patients receiving iE&iM. There was a significant drop in mean PA pressure (MPAP) (-4.8 ± 8.7, P = 0.010), systolic PA pressure (SPAP) (-8.2 ± 12.8, P = 0.003), RV end-diastolic pressure (RVEDP) (-2.1 ± 2.8, P < 0.001) and RV diastolic pressure gradient (RVDPG) (-1.7 ± 1.4, P < 0.001) after 17 ± 9 minutes of iE&iM administration. Patients also had a significant increase in RV outflow tract (RVOT) gradient (3.7 ± 4.7, P < 0.001), RV maximal rate of pressure rise during early systole (dP/dt max) (68.3 ± 144.7, P = 0.024), and left ventricular (LV) dP/dt max (66.4 ± 90.1, P < 0.001). Change in RVOT gradient was only observed in those with a positive pulmonary vasodilator response to treatment. Treatment with iE&iM did not present adverse effects when compared with a matched case-control group. CONCLUSIONS: Coadministration of iE&iM in cardiac surgery patients presenting with PH or signs of RV dysfunction is a safe and effective treatment approach in improving RV function. Appearance of a transient increase in RVOT gradient after iE&iM could be useful to predict response to treatment.

Emerging Applications of Extracardiac Ultrasound in Critically Ill Cardiac Patients.

Point-of-care ultrasound has evolved as an invaluable diagnostic modality and procedural guidance tool in the care of critically ill cardiac patients. Beyond focused cardiac ultrasound, additional extracardiac ultrasound modalities may provide important information at the bedside. In addition to new uses of existing modalities, such as pulsed-wave Doppler ultrasound, the development of new applications is fostered by the implementation of additional features in mid-range ultrasound machines commonly acquired for intensive care units, such as tissue elastography, speckle tracking, and contrast-enhanced ultrasound quantification software. This review explores several areas in which ultrasound imaging technology may transform care in the future. First, we review how lung ultrasound in mechanically ventilated patients can enable the personalization of ventilator parameters and help to liberate them from mechanical ventilation. Second, we review the role of venous Doppler in the assessment of organ congestion and how tissue elastography may complement this application. Finally, we explore how contrast-enhanced ultrasound could be used to assess changes in organ perfusion.