Hemodynamic monitoring in the critically ill: an overview of current cardiac output monitoring methods

Factors Influencing Recirculation in Veno-Venous Extracorporeal Membrane Oxygenation: Insights From a Controlled Bench Study

This study investigated factors influencing recirculation in veno-venous extracorporeal membrane oxygenation (VV ECMO) using a controlled bench model comprising a VV ECMO circuit and a mock circulatory loop with a porcine cadaver heart simulating human right heart anatomy. Several single-lumen cannula (SLC) configurations (15/21 Fr, 15/23 Fr, 17/21 Fr, 17/23 Fr) and double-lumen cannulae (DLC) from two manufacturers were evaluated. Different cannula positions (distance, rotation), ECMO flow (ECF), cardiac output (CO), central venous pressure (CVP) were assessed for their impact on recirculation, measured by ultrasound dilution method. In 31 experimental series (1,641 measurements), increasing CO consistently reduced recirculation, irrespective of cannulation configuration (SLC: R = -0.99; DLC: R = -0.87; p < 0.01), whereas elevating ECF increased it. CO/ECF ratio had a greater impact than CO or ECF alone, with higher values reducing recirculation in both SLC and DLC. In SLC, cannula size or retraction beyond a threshold distance had minimal effect on recirculation. However, in DLCs exact positioning is crucial, as suboptimal placement or rotation markedly increased recirculation.CO and CO/ECF ratio are key determinants of recirculation in all cannulation scenarios. In clinical settings, accurate monitoring of recirculation and CO is essential to optimize VV ECMO oxygen transfer efficiency and should become standard troubleshooting practice.

Refeeding syndrome risk at ICU admission is an independent predictor of ICU readmission but it is not associated with mortality or length of stay in critically ill patients

OBJECTIVES

This study evaluated the association between refeeding syndrome (RFS) risk and intensive care unit (ICU)/in-hospital mortality and length of stay (LOS) and ICU readmission in critically ill patients.

METHODS

This secondary analysis of a cohort study included patients aged ≥ 18 years admitted at ICU 24 h before data collection. We evaluated RFS risk based on the National Institute for Health and Clinical Excellence (NICE), stratifying it into four categories (no, low, high, and very-high risk).

SETTING

Five adult ICUs in Brazil.

MAIN OUTCOME MEASURES

ICU/in-hospital mortality and LOS and ICU readmission data were obtained from electronic medical records analysis, following patients until discharge (alive or not).

RESULTS

The study involved 447 patients, categorized into no (19.2 %), low (28.6 %), high (48.8 %), and very-high (3.4 %) RFS risk groups. No significant differences emerged between the two groups (at RFS risk and no RFS risk) regarding the ICU death ratio (34.3 % versus 23.4 %) and LOS (5 versus 4 days), respectively. In contrast, patients at RFS risk experienced higher in-hospital mortality rates (34.3 % versus 23.4 %) prolonged hospital LOS (21 days versus 17 days), and increased ICU readmission rates (15 % versus 8.4 %) than patients without RFS risk. After adjusting for age and Sequential Organ Failure Assessment (SOFA) Score, we found no association between RFS risk and increased mortality in the ICU or hospital. Also, there was no significant association between RFS risk and prolonged LOS in the ICU or hospital setting. However, patients identified as at risk of RFS showed nearly double the odds of ICU readmission (Odds ratio, 1.90; 95 % CI 1.02-3.43).

CONCLUSIONS

This study found no significant association between RFS risk and increased mortality in both the ICU and hospital settings, nor was there a significant association with prolonged LOS in the ICU or hospital among critically ill patients. However, patients at risk of RFS exhibited nearly double the odds of ICU readmission.

IMPLICATIONS FOR CLINICAL PRACTICE

Our findings may contribute to understanding risks associated with ICU readmissions, highlighting the complexity of discharge decision-making through comprehensive assessments.

Monitor smart, use better: the future of haemodynamic monitoring

The review article "Haemodynamic Monitoring During Noncardiac Surgery" offers valuable insights but lacks evidence linking specific haemodynamic strategies to improved outcomes. There's a need for standardized protocols, ongoing clinician education, and further validation of new technologies. Additionally, balancing the use of invasive versus noninvasive methods and addressing cost-effectiveness and sustainability are essential. Continued research and adaptive practices are crucial for optimizing perioperative care.

Machine Learning-Based Cardiac Output Estimation Using Photoplethysmography in Off-Pump Coronary Artery Bypass Surgery

Background/Objectives: Hemodynamic monitoring is crucial for managing critically ill patients and those undergoing major surgeries. Cardiac output (CO) is an essential marker for diagnosing hemodynamic deterioration and guiding interventions. The gold standard thermodilution method for measuring CO is invasive, prompting a search for non-invasive alternatives. This pilot study aimed to develop a non-invasive algorithm for classifying the cardiac index (CI) into low and non-low categories using finger photoplethysmography (PPG) and a machine learning model. Methods: PPG and continuous thermodilution CO data were collected from patients undergoing off-pump coronary artery bypass graft surgery. The dataset underwent preprocessing, and features were extracted and selected using the Relief algorithm. A CatBoost machine learning model was trained and evaluated using a validation and testing phase approach. Results: The developed model achieved an accuracy of 89.42% in the validation phase and 87.57% in the testing phase. Performance was balanced across low and non-low CO categories, demonstrating robust classification capabilities. Conclusions: This study demonstrates the potential of machine learning and non-invasive PPG for accurate CO classification. The proposed method could enhance patient safety and comfort in critical care and surgical settings by providing a non-invasive alternative to traditional invasive CO monitoring techniques. Further research is needed to validate these findings in larger, diverse patient populations and clinical scenarios.

Performance evaluation of non-invasive cardiac output monitoring device (HemoVista) based on multi-channel thoracic impedance plethysmography technology

BACKGROUND

A non-invasive method of measuring cardiac output (CO) can be beneficial in the care of critically ill patients. HemoVista (BiLab Co., Ltd.) is a medical device that measures CO non-invasively using multi-channel impedance plethysmography technology. The purpose of this study was to exploratively evaluate the performance of HemoVista in critically ill patients undergoing CO monitoring with the FloTrac (Edwards Lifesciences).

METHODS

After non-invasively installing the HemoVista sensor in critically ill patients whose CO was monitored with the FloTrac, CO values measured by both devices were collected for 30 minutes. Cardiac output measured by both devices was selected every 10 seconds, creating approximately 360 data pairs per patient. Linear correlation analysis with Pearson correlation coefficients, Bland-Altman analysis, and four-quadrant plot analysis were performed to evaluate the performance of HemoVista.

RESULTS

A total of 7,138 pairs of CO data from the 20 patients were included in the analysis. A significant correlation was observed between the two methods of measuring CO (Pearson's r=0.489, P<0.001). The mean bias was 1.03 L/min, the 95% CI for the limit of agreement was -1.83 L/min to 3.93 L/min and the percentage error was 55.8%. The concordance rate of time-dependent CO between the two devices was 14.6%.

CONCLUSIONS

It was observed that the current version of HemoVista has unsuitable performance for use in intensive care units. To be used for critically ill patients, the algorithm must be improved and reevaluated with an enhanced version.

A Cadaveric Case Study on the Abdomen: A Temple of Surprises

Femoro-femoral bypass grafts (FFBG) are performed to connect the major vessels of the lower extremities, such as the femoral arteries, to treat patients who have injured or occluded iliac arteries. Typically, patients with multiple comorbidities, such as heart failure, aneurysms, or diabetes, have a significantly higher risk of complications for open, invasive procedures to correct lower limb ischemia. This graft poses as an effective, less invasive option to treat lower-limb ischemia for higher-risk patients. This case study presents a finding of FFBG in an 82-year-old male cadaver during cadaveric dissection in the gross anatomy lab at Geisinger Commonwealth School of Medicine in Scranton, Pennsylvania. Based on the initial findings of cardiomegaly with a triple coronary artery bypass graft (CABG) and pulmonary hypertension in the thoracic cavity and evidence of massive umbilical hernioplasty involving extensive mesh repair, our initial assumption of an FFBG placement in this cadaver was to increase perfusion to lower limbs, circumventing the need for surgical intervention due to the above-mentioned comorbidities, which act as risk factors. However, the discovery of a massive abdominal aortic aneurysm (AAA) measuring 26 cm in circumference with evidence of dissection of its wall and the presence of a stent within the aorta and common iliac arteries placed there as an endovascular aneurysm repair (EVAR) procedure came as a surprise. Publication of such findings provides awareness to curious individuals about the existence of multiple health concerns an individual suffers and how the medical as well as surgical teams work together to provide optimal treatment care to improve their standard of living and prolong their lifespan.

Prevalence of Diastolic Dysfunction in Critically Ill Patients Admitted to Intensive Care Unit from a Tertiary Care Hospital: A Prospective Observational Study

Aim

Critically ill individuals may have left ventricular diastolic dysfunction (LVDD) which can prolong their intensive care unit (ICU) stay. The purpose of this study was to determine the prevalence of LVDD in critically ill adult patients requiring mechanical ventilation in ICU, the effect of LVDD on 28-day survival, and weaning from mechanical ventilation.

Methodology

A total of 227 adults who had been on mechanical ventilation for more than 48 hours in an ICU were recruited for this study. The study's parameters were recorded on the third day of mechanical ventilation using a low-frequency phased array probe. A simplified definition of LVDD in critically ill adults was utilized to determine the presence or absence of LVDD. Weaning failure and 28-day mortality were noted.

Results

The prevalence of LVDD in adults requiring mechanical ventilation in the ICU was found to be 35.4% (n = 79). Patients with LVDD had the odds of having a 28-day mortality increase by 7.48 (95% CI: 3.24-17.26, p < 0.0001). Patients with LVDD had the odds of having weaning failure increase by 5.37 (95% CI: 2.17-13.26, p = 0.0003).

Conclusion

Measures should be taken to detect critically ill adults with LVDD with systolic dysfunction or heart failure with preserved ejection fraction early so that their fluid balance, myocardial contractility, and afterload can be optimized to minimize their morbidity and mortality.

Highlights

Critically ill adults with LVDD may have adverse outcomes. Hence, protocol should be in place for diagnosing LVDD early in critically ill adults thereby, measures can be taken to minimize morbidity in those patients.

How to cite this article

Luitel B, Senthilnathan M, Cherian A, Suganya S, Adole PS. Prevalence of Diastolic Dysfunction in Critically Ill Patients Admitted to Intensive Care Unit from a Tertiary Care Hospital: A Prospective Observational Study. Indian J Crit Care Med 2024;28(9):832-836.

Bioreactance noninvasive cardiac output monitoring in euvolemic adult horses subjected with 7.2% saline and 6% hydroxyethyl starch (130/0.4) solution infusions

OBJECTIVE

To compare the ability of bioreactance noninvasive cardiac output (BR-NICO) with thermodilution cardiac output (TDCO) for the measurement of cardiac output (CO) in healthy adult horses receiving 2 different IV volume replacement solutions.

DESIGN

Prospective randomized crossover study from September to November 2021.

SETTING

University teaching hospital.

ANIMALS

Six university-owned adult horses.

INTERVENTIONS

Horses were randomly assigned to receive 7.2% hypertonic saline solution (HSS) or 6% hydroxyethyl starch (130/0.4) solution (HETA). BR-NICO and TDCO were measured simultaneously at baseline, 10, 20, 30, 40, 50, 60, 90, and 120 minutes before fluid administration and again at the same times after starting a bolus infusion of IV volume replacers. All solutions were administered within 10 minutes.

MEASUREMENTS AND MAIN RESULTS

BR-NICO and TDCO were strongly correlated (Pearson r2 = 0.93; P < 0.01). Regression analysis showed the relationship between TDCO and BR-NICO was BR-NICO = 0.48 × TDCO + 0.6. For the corrected BR-NICO values, the Bland-Altman agreement mean bias and lower/upper limits of agreement were -0.62 and -5.3 to 3.9 L/min, respectively. Lin's concordance (95% confidence interval) between methods was 0.894 (0.825-1.097). Compared with baseline, HSS increased the CO at 10 and 20 minutes (TDCO and BR-NICO). Compared with baseline, HETA decreased the CO at 10 and 20 minutes (TDCO and BR-NICO) and increased the CO at 90 (TDCO only) and 120 minutes (TDCO and BR-NICO).

CONCLUSIONS

BR-NICO strongly agreed with TDCO in the measurement of CO in healthy unsedated adult horses. HSS administration significantly increased CO in the first 30 minutes, while HETA initially decreased CO at 10 minutes but increased CO to above baseline values by 90 minutes.

Echocardiography as a Vital Tool in Assessing Shock: A Comprehensive Review

Shock is a critical condition characterized by inadequate tissue perfusion, leading to cellular hypoxia and organ dysfunction. Early and accurate assessment is crucial for timely intervention and improved patient outcomes. Echocardiography has emerged as a vital tool in the assessment of shock, offering real-time visualization of cardiac anatomy, function, and hemodynamics. This comprehensive review aims to elucidate the role of echocardiography in shock assessment by providing an overview of its principles, techniques, and clinical applications. We discuss the importance of early diagnosis, identification of underlying pathology, monitoring response to therapy, and prognostic value offered by echocardiography in managing shock. Furthermore, we explore its utility in different types of shock, including hypovolemic, cardiogenic, distributive, and obstructive shock. Challenges and limitations of echocardiography, as well as future directions and innovations, are also discussed. Through a synthesis of current evidence and clinical insights, this review underscores the significance of echocardiography in optimizing shock management and highlights areas for further research and development.

Successful treatment of severe calcium channel blocker poisoning, new experience with the guidance of invasive hemodynamic monitoring in a 17-year-old girl: a case report

BACKGROUND

Calcium channel blocker poisoning is one of the most lethal cardiac drugs overdoses. Calcium and high-dose insulin infusion are the first-line therapy for symptomatic patients, and Intralipid emulsion infusion is useful for refractory cases.

CASE PRESENTATION

In this report, we describe a 17-year-old Iranian girl who took 250 mg of the drug for a suicidal attempt and presented with refractory hypotension and non-cardiogenic pulmonary edema treated successfully with the guidance of invasive hemodynamic parameters.

CONCLUSION

For complicated cases, in addition to supportive care and adjuvant therapy such as high-dose insulin and Intralipid, it is mandatory to utilize advanced hemodynamic monitoring to treat hypotension in severe calcium channel blocker poisoning to guide the treatment.

Reviving Hope: A Comprehensive Review of Post-resuscitation Care in Pediatric ICUs After Cardiac Arrest

This comprehensive review thoroughly examines post-resuscitation care in pediatric ICUs (PICUs) following cardiac arrest. The analysis encompasses adherence to resuscitation guidelines, advances in therapeutic interventions, and the nuanced management of neurological, cardiovascular, and respiratory considerations during the immediate post-resuscitation phase. Delving into the complexities of long-term outcomes, cognitive and developmental considerations, and rehabilitation strategies, the review emphasizes the importance of family-centered care for pediatric survivors. A call to action is presented, urging continuous education, research initiatives, and quality improvement efforts alongside strengthened multidisciplinary collaboration and advocacy for public awareness. Through implementing these principles, healthcare providers and systems can collectively contribute to ongoing advancements in pediatric post-resuscitation care, ultimately improving outcomes and fostering a culture of excellence in pediatric critical care.

Goal-directed therapy in cardiovascular surgery: A case series study

Hemodynamic and intravascular volume monitoring has been utilized and significantly improved thanks to the technology revolution. Goal-Directed Therapy (GDT) derived from this advanced monitoring is beneficial for complex surgeries, and it shifted the medical approaches from static therapy to more personalized functional treatments. Conventional monitoring methods such as blood pressure, heart rate, urinary output, and central venous pressure are commonly used. However, studies have shown these routine parameters often cannot precisely estimate the quality of tissue perfusion. Tissue hypoperfusion and hypoxia play a crucial role in initiating a systemic inflammatory response after prolonged surgeries, resulting in unstable hemodynamic condition of the patients. Several studies reported the importance of GDT in non-cardiac surgeries and there are few reports on cardiac surgeries. However, tissue perfusion and fluid management are more critical in complex and prolonged cardiovascular surgeries to avoid complications such as low cardiac output syndrome and renal or pulmonary dysfunction. Different advanced hemodynamic monitorings have been utilized perioperatively in cardiac surgery to help decision-making on inotrope and fluid management. In this article we present 5 cases of usefulness hemodynamic monitoring in patients who underwent cardiovascular surgeries.

Unveiling Breakthroughs in Post-resuscitation Supportive Care for Out-of-Hospital Cardiac Arrest Survivors: A Narrative Review

Survivors of out-of-hospital cardiac arrest (OHCA) experience significant mortality rates and neurological impairment, potentially attributed to the hypoxic-ischemic injury sustained amid the cardiac arrest episode. Post-resuscitation care plays a crucial role in determining outcomes for survivors of OHCA. Supportive therapies have proven to be influential in shaping these outcomes. However, targeting higher blood pressure or oxygen levels during the post-resuscitative phase has not been shown to offer any mortality or neurological benefits. In terms of maintaining hemodynamic instability after resuscitation, it is recommended to use norepinephrine rather than epinephrine. While extracorporeal cardiopulmonary resuscitation has shown promising results, targeted temperature management has been found ineffective in improving outcomes despite its previous potential. This review also investigates various challenges and barriers associated with the practical implementation of these supportive therapies in clinical settings. The review also highlights areas ripe for future research and proposes potential directions to further enhance post-resuscitation supportive care for OHCA survivors.

Lung Ultrasonography Is an Acceptable Imaging Modality to Diagnose COVID-19 and Effectively Correlates with HRCT Chest-A Prospective Study

It has been validated beyond doubt that High-Resolution Computed Tomography (HRCT) chest and to some extent chest radiographs have a role in corona virus disease-19 (COVID-19). Much less is known about the role of lung ultrasonography (LUS) in COVID-19. In this paper, our main purpose was to gauge the relationship between LUS and chest HRCT in reverse transcriptase polymerase chain reaction (RT-PCR) documented cases of COVID-19, as well as in those with high suspicion of COVID-19 with negative RT-PCR. It was a prospective study carried out at our tertiary care hospital, namely, SKIMS Soura. The total number of patients in this study were 152 (200 patients were selected out of which only 152 had undergone both LUS and chest HRCT). The patients were subjected to both LUS and chest HRCT. The radiologist who performed LUS was blinded to clinical findings and HRCT was evaluated by a radiologist with about a decade of experience. The LUS findings compatible with the disease were subpleural consolidations, B-lines and irregular pleural lines. Findings that were compatible with COVID-19 on chest HRCT were bibasilar, subpleural predominant ground glass opacities, crazy paving and consolidations. COVID-19-positive patients were taken up for chest HRCT for disease severity stratification and were also subjected to LUS. On HRCT chest, the imaging abnormalities compatible with COVID-19 were evident in 110 individuals (72.37%), and on Lung Ultrasound they were observed in 120 individuals (78.95%). Imaging of COVID-19 patients assessed by both LUS and HRCT chest,, showed a positive correlation (p < 0.0001). The study revealed a sensitivity of 88%, a specificity of 76.62%, a positive predictive value of 78.57% and a negative predictive value of 86.76%. None of the individuals with a diagnosis of COVID-19 on HRCT were missed on LUS. An excellent correlation was derived between the LUS score and CT total severity score (p < 0.0001 with a kappa of 0.431). Similar precision compared with chest HRCT in the detection of chest flaws in COVID-19 patients was obtained on LUS.

The role of cardiac power and lactate clearance as an indicator of resuscitation success among pediatric patients with shock in the intensive care unit of Cipto Mangunkusumo Hospital

BACKGROUND

Shock in children remains the primary cause of mortality and morbidity worldwide. Furthermore, its management outcome is improved using many hemodynamic parameters, such as cardiac power (CP) and lactate clearance (LC). Cardiac power is a contractility index based on the measurement of flow and pressure, and it is a relatively new hemodynamic parameter with limited studies. In contrast, LC has been proven useful as a target outcome in shock resuscitation. This study aims to explore the values of CP and LC in pediatric shock and their association with clinical outcomes.

METHODS

This prospective observational study was conducted on children (1 month-18 years old) with shock at Cipto Mangunkusumo Hospital, Indonesia, from April to October 2021. We measured CP using ultrasonic cardiac output monitoring (USCOM®) and serum lactate levels at 0, 1, 6, and 24 h post-initial resuscitation. Subsequently, the variables were described and analyzed with the resuscitation success, length of stay, and mortality.

RESULTS

A total of 44 children were analyzed. There were 27 (61.4%), 7 (15.9%), 4 (9.1%), 4 (9.1%), and 2 (4.5%) cases of septic, hypovolemic, cardiogenic, distributive, and obstructive shock, respectively. Within the first 24 h post-initial resuscitation, CP and LC had an increasing trend. Compared to children who had successful resuscitation, those who did not have successful resuscitation had similar CP at all time points (p > 0.05) and lower LC at 1 and 24 h post-initial resuscitation (p < 0.05). Lactate clearance was an acceptable predictor of resuscitation success (area under the curve: 0.795 [95% CI: 0.660-0.931]). An LC of 7.5% had a sensitivity, specificity, positive predictive value, and negative predictive value of 75.00%, 87.5%, 96.43%, and 43.75%, respectively. Lactate clearance in the first hour post-initial resuscitation had a weak correlation (r=-0.362, p < 0.05) with hospital length of stay. We found no difference in CP and LC among survivors compared to nonsurvivors.

CONCLUSIONS

We found no evidence that CP was associated with resuscitation success, length of stay, or mortality. Meanwhile, higher LC was associated with successful resuscitation and shorter length of stay at the hospital, but not mortality.

Treatment of septic shock in two pediatric patients with severe diabetic ketoacidosis using invasive hemodynamic monitoring: a case report

BACKGROUND

Diabetic ketoacidosis (DKA) is a life-threatening complication of diabetes mellitus. DKA associated with shock is a rare condition that occurs due to the fluid deficit or septic shock. It is not easy to differentiate these two conditions by clinical judgment and laboratory findings. Although the fluid therapy is the mainstay in DKA treatment, it looks like a double-edged sword-underhydration may result in organ failure whereas overhydration may lead to pulmonary and cerebral edema (CE).

CASE PRESENTATION

Herein, we report on two pediatric patients presenting with DKA and septic shock. The first patient was an 8-year-old boy newly diagnosed with type 1 diabetes mellitus (T1DM) who presented with DKA and septic shock. We used a device for continuous hemodynamic monitoring (proAQT) to estimate his volume status. The patient was extubated 48 hours of hospitalization; the DKA was resolved after 52 hours of admission. He was discharged home in good condition on the 5th day. The second patient was a 13-year-old girl, a known case of T1DM, who presented with mixed DKA- hyperosmolar-hyperglycemic state (HHS) and septic shock. She was intubated and treated according to the data derived from pulse Contour Cardiac Output (PiCCO). After 3 days, she was extubated and transferred to the ward in good condition.

CONCLUSION

Using invasive hemodynamic monitoring in critically ill children with severe DKA and hypotension might guide the physicians for hydration and selecting the most appropriate inotrope.

Phyto-assisted synthesis of zinc oxide nanoparticles for developing antibiofilm surface coatings on central venous catheters

Medical devices such as Central Venous Catheters (CVCs), are routinely used in intensive and critical care settings. In the present scenario, incidences of Catheter-Related Blood Stream Infections (CRBSIs) pose a serious challenge. Despite considerable advancements in the antimicrobial therapy and material design of CVCs, clinicians continue to struggle with infection-related complications. These complications are often due colonization of bacteria on the surface of the medical devices, termed as biofilms, leading to infections. Biofilm formation is recognized as a critical virulence trait rendering infections chronic and difficult to treat even with 1,000x, the minimum inhibitory concentration (MIC) of antibiotics. Therefore, non-antibiotic-based solutions that prevent bacterial adhesion on medical devices are warranted. In our study, we report a novel and simple method to synthesize zinc oxide (ZnO) nanoparticles using ethanolic plant extracts of Eupatorium odoratum. We investigated its physio-chemical characteristics using Field Emission- Scanning Electron Microscopy and Energy dispersive X-Ray analysis, X-Ray Diffraction (XRD), Photoluminescence Spectroscopy, UV-Visible and Diffuse Reflectance spectroscopy, and Dynamic Light Scattering characterization methods. Hexagonal phase with wurtzite structure was confirmed using XRD with particle size of ∼50 nm. ZnO nanoparticles showed a band gap 3.25 eV. Photoluminescence spectra showed prominent peak corresponding to defects formed in the synthesized ZnO nanoparticles. Clinically relevant bacterial strains, viz., Proteus aeruginosa PAO1, Escherichia coli MTCC 119 and Staphylococcus aureus MTCC 7443 were treated with different concentrations of ZnO NPs. A concentration dependent increase in killing efficacy was observed with 99.99% killing at 500 μg/mL. Further, we coated the commercial CVCs using green synthesized ZnO NPs and evaluated it is in vitro antibiofilm efficacy using previously optimized in situ continuous flow model. The hydrophilic functionalized interface of CVC prevents biofilm formation by P. aeruginosa, E. coli and S. aureus. Based on our findings, we propose ZnO nanoparticles as a promising non-antibiotic-based preventive solutions to reduce the risk of central venous catheter-associated infections.

Measurement of Cardiac Output Using an Ultrasonic Cardiac Output Monitor (USCOM) in Patients with Single-Ventricle Physiology

We evaluate the validity of cardiac index (CI) measurements utilizing the Ultrasonic Cardiac Output Monitor (USCOM), a non-invasive Doppler ultrasound device, by comparing measurements to cardiac catheterization-derived CI measurements in patients with single-ventricle physiology. USCOM measurements were repeated three times for each patient at the beginning of a cardiac catheterization procedure for twenty-six patients undergoing elective pre-Glenn or pre-Fontan catheterization. CI was measured by USCOM and was calculated from cardiac catheterization data using Fick's method. Bland-Altman analysis for CI showed bias of 0.95 L/min/m² with the 95% limits of agreement of - 1.85 and 3.75. Pearson's correlation coefficient was 0.89 (p < 0.001) indicating a strong positive relationship between USCOM and cardiac catheterization CI measurements. When excluding two patients with significant dilation of the neo-aortic valve (z-score >  + 5), the bias improved to 0.66 L/min/m² with the 95% limits of agreement of - 1.38 and 2.70. Percent error of limits of agreement was 34%. There was excellent intra-operator reproducibility of USCOM CI measurements with an intra-class coefficient of 0.96. We demonstrate the use of USCOM to measure CI in patients with single-ventricle physiology for the first time, showing acceptable agreement of the CI measurements between USCOM and cardiac catheterization with a high intra-operator reproducibility.

Non-invasive continuous blood pressure monitoring using the ClearSight system for pregnant women at high risks of post-partum hemorrhage: comparison with invasive blood pressure monitoring during cesarean section

Objective

This study aimed to investigate the accuracy and precision of continuous, non-invasive blood pressure obtained using the ClearSight system by comparing it with invasive arterial blood pressure, and to assess the hemodynamic changes using the ClearSight system in patients undergoing cesarean section.

Methods

Arterial pressure was measured invasively with an intra-arterial catheter and non-invasively using the ClearSight system during cesarean section in patients with placenta previa or placenta accreta. Blood pressure measurements obtained using these two means were then compared.

Results

Total 1,277 blood pressure measurement pairs were collected from 21 patients. Under Bland-Altman analysis, the ClearSight system demonstrated an acceptable accuracy with a bias and standard deviation of 8.8±13.4 mmHg for systolic blood pressure, -6.3±7.1 mmHg for diastolic blood pressure, and -2.7±8.0 mmHg for median blood pressure. Cardiac index levels were significantly elevated during fetal delivery and 5 minutes after placental removal, and systemic vascular resistance index levels were significantly decreased during fetal delivery and 40 minutes after placental removal.

Conclusion

In patients undergoing cesarean section, the ClearSight system showed excellent accuracy and precision compared to that of the currently used invasive monitoring system.

Hemodynamic monitoring and management of pediatric septic shock

Sepsis remains a major cause of morbidity and mortality among children worldwide. Furthermore, refractory septic shock and multiple organ dysfunction syndrome are the most critical groups which account for a high mortality rate in pediatric sepsis, and their clinical course often deteriorates rapidly. Resuscitation based on hemodynamics can provide objective values for identifying the severity of sepsis and monitoring the treatment response. Hemodynamics in sepsis can be divided into two groups: basic and advanced hemodynamic parameters. Previous therapeutic guidance of early-goal directed therapy (EGDT), which resuscitated based on the basic hemodynamics (central venous pressure and central venous oxygen saturation (ScvO2)) has lost its advantage compared with “usual care”. Optimization of advanced hemodynamics, such as cardiac output and systemic vascular resistance, has now been endorsed as better therapeutic guidance for sepsis. Despite this, there are still some important hemodynamics associated with prognosis. In this article, we summarize the common techniques for hemodynamic monitoring, list important hemodynamic parameters related to outcomes, and update evidence-based therapeutic recommendations for optimizing resuscitation in pediatric septic shock.

Successful Treatment of Severely Hypotensive Pediatric Patients with Multisystem Inflammatory Syndrome in Children (MIS-C) with the Guidance of Invasive Hemodynamic Monitoring: A Report of Three Cases

Introduction: Since the beginning of the coronavirus disease 2019 (COVID-19) outbreak, it was assumed that infection rate in pediatric patients is lower than in adults and that infection is less severe in children than adult patients. Recently, there have been several reports and case series presenting critically-ill children with COVID-19, but still, severe hypotension is rare in pediatric patients with COVID-19. Case Presentation: We describe three pediatric cases with COVID-19 who presented with multi-system organ failure and severe hypotension treated with the guidance of the parameters of an invasive continuous hemodynamic monitoring device. We also compare their parameters with few articles on pediatric sepsis parameters. Conclusions: Although we usually start the treatment of hypotensive pediatric patients with hydration and epinephrine as an inotrope, in our cases, we required a different treatment plan according to the hemodynamic monitoring parameters, which indicates the value of the utilization of these devices in pediatric intensive care units

Hemodynamic Monitoring in Patients With Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

Aneurysmal subarachnoid hemorrhage (aSAH) often causes cardiopulmonary dysfunction. Therapeutic strategies can be guided by standard (invasive arterial/central venous pressure measurements, fluid balance assessment), and/or advanced (pulse index continuous cardiac output, pulse dye densitometry, pulmonary artery catheterization) hemodynamic monitoring. We conducted a systematic review and meta-analysis of the literature to determine whether standard compared with advanced hemodynamic monitoring can improve patient management and clinical outcomes after aSAH. A literature search was performed for articles published between January 1, 2000 and January 1, 2019. Studies involving aSAH patients admitted to the intensive care unit and subjected to any type of hemodynamic monitoring were included. A total of 14 studies were selected for the qualitative synthesis and 3 randomized controlled trials, comparing standard versus advanced hemodynamic monitoring, for meta-analysis. The incidence of delayed cerebral ischemia was lower in the advanced compared with standard hemodynamic monitoring group (relative risk [RR]=0.71, 95% confidence interval [CI]=0.52-0.99; P=0.044), but there were no differences in neurological outcome (RR=0.83, 95% CI=0.64-1.06; P=0.14), pulmonary edema onset (RR=0.44, 95% CI=0.05-3.92; P=0.46), or fluid intake (mean difference=-169 mL; 95% CI=-1463 to 1126 mL; P=0.8) between the 2 groups. In summary, this systematic review and meta-analysis found only low-quality evidence to support the use of advanced hemodynamic monitoring in selected aSAH patients. Because of the small number and low quality of studies available for inclusion in the review, further studies are required to investigate the impact of standard and advanced hemodynamic monitoring-guided management on aSAH outcomes.

The effects of hemodynamic monitoring using the PiCCO system on critically ill patients

OBJECTIVE

We aimed to evaluate the effects of hemodynamic monitoring using the pulse index continuous cardiac output (PiCCO) system with critically ill patients.

METHODS

In total, 292 patients with primary physiological abnormalities of hypotension (n = 180) or hypoxemia (n = 112) were evaluated. The attending physicians completed a questionnaire before each catheterization. After each catheterization, the attending physicians reviewed each chart to determine the possibility of altering the therapy.

RESULTS

In the hypotension subgroup, the attending physicians showed less accuracy in predicting the global end-diastolic index values (23.9%, 43/180), with a significant difference, and more accuracy in predicting the extravascular lung water index values (58.9%, 66/112), without a significant difference from the patients in the hypoxemia subgroup. In the hypotension patients, the lactate clearance rate within 6 h was significantly higher (36.4 ± 9.6 vs 21.3 ± 9.5; P<0.0001) when the hemodynamic monitoring led to therapeutic changes.

CONCLUSIONS

The hemodynamic variables obtained using the PiCCO system improved the accuracy of the bedside evaluations and led to alterations in the therapeutic plans, particularly among the hypotension patients. The therapy changes showed no improvement in the overall mortality but were associated with improved tissue perfusion among the hypotension patients.

Prevention of Cardiac Surgery-Associated Acute Kidney Injury by Implementing the KDIGO Guidelines in High-Risk Patients Identified by Biomarkers: The PrevAKI-Multicenter Randomized Controlled Trial

BACKGROUND

Prospective, single-center trials have shown that the implementation of the Kidney Disease: Improving Global Outcomes (KDIGO) recommendations in high-risk patients significantly reduced the development of acute kidney injury (AKI) after surgery. We sought to evaluate the feasibility of implementing a bundle of supportive measures based on the KDIGO guideline in high-risk patients undergoing cardiac surgery in a multicenter setting in preparation for a large definitive trial.

METHODS

In this multicenter, multinational, randomized controlled trial, we examined the adherence to the KDIGO bundle consisting of optimization of volume status and hemodynamics, functional hemodynamic monitoring, avoidance of nephrotoxic drugs, and prevention of hyperglycemia in high-risk patients identified by the urinary biomarkers tissue inhibitor of metalloproteinases-2 [TIMP-2] and insulin growth factor-binding protein 7 [IGFBP7] after cardiac surgery. The primary end point was the adherence to the bundle protocol and was evaluated by the percentage of compliant patients with a 95% confidence interval (CI) according to Clopper-Pearson. Secondary end points included the development and severity of AKI.

RESULTS

In total, 278 patients were included in the final analysis. In the intervention group, 65.4% of patients received the complete bundle as compared to 4.2% in the control group (absolute risk reduction [ARR] 61.2 [95% CI, 52.6-69.9]; P < .001). AKI rates were statistically not different in both groups (46.3% intervention versus 41.5% control group; ARR -4.8% [95% CI, -16.4 to 6.9]; P = .423). However, the occurrence of moderate and severe AKI was significantly lower in the intervention group as compared to the control group (14.0% vs 23.9%; ARR 10.0% [95% CI, 0.9-19.1]; P = .034). There were no significant effects on other specified secondary outcomes.

CONCLUSIONS

Implementation of a KDIGO-derived treatment bundle is feasible in a multinational setting. Furthermore, moderate to severe AKI was significantly reduced in the intervention group.

Development of a Deep Learning Network to Classify Inferior Vena Cava Collapse to Predict Fluid Responsiveness

OBJECTIVES

To create a deep learning algorithm capable of video classification, using a long short-term memory (LSTM) network, to analyze collapsibility of the inferior vena cava (IVC) to predict fluid responsiveness in critically ill patients.

METHODS

We used a data set of IVC ultrasound (US) videos to train the LSTM network. The data set was created from IVC US videos of spontaneously breathing critically ill patients undergoing intravenous fluid resuscitation as part of 2 prior prospective studies. We randomly selected 90% of the IVC videos to train the LSTM network and 10% of the videos to test the LSTM network's ability to predict fluid responsiveness. Fluid responsiveness was defined as a greater than 10% increase in the cardiac index after a 500-mL fluid bolus, as measured by bioreactance.

RESULTS

We analyzed 211 videos from 175 critically ill patients: 191 to train the LSTM network and 20 to test it. Using standard data augmentation techniques, we increased our sample size from 191 to 3820 videos. Of the 175 patients, 91 (52%) were fluid responders. The LSTM network was able to predict fluid responsiveness moderately well, with an area under the receiver operating characteristic curve of 0.70 (95% confidence interval [CI], 0.43-1.00), a positive likelihood ratio of infinity, and a negative likelihood ratio of 0.3 (95% CI, 0.12-0.77). In comparison, point-of-care US experts using video review offline and manual diameter measurement via software caliper tools achieved an area under the receiver operating characteristic curve of 0.94 (95% CI, 0.83-0.99).

CONCLUSIONS

We demonstrated that an LSTM network can be trained by using videos of IVC US to classify IVC collapse to predict fluid responsiveness. Our LSTM network performed moderately well given the small training cohort but worse than point-of-care US experts. Further training and testing of the LSTM network with a larger data sets is warranted.

Hemodynamic monitoring in cardiogenic shock

PURPOSE OF REVIEW

Cardiogenic shock remains a major cause of mortality today. With recent advancements in invasive mechanical support strategies, reperfusion practice, and a new classification scheme is proposed for cardiogenic shock, an updated review of the latest hemodynamic monitoring techniques is important.

RECENT FINDINGS

Multiple recent studies have emerged supporting the use of pulmonary artery catheters in the cardiogenic shock population. Data likewise continues to emerge on the use of echocardiography and biomarker measurement in the care of these patients.

SUMMARY

The integration of multiple forms of hemodynamic monitoring, spanning noninvasive and invasive modalities, is important in the diagnosis, staging, initial treatment, and subsequent management of the cardiogenic shock patient.

A 7-year-old boy with toxic epidermal necrolysis, heart failure, and sepsis treated with the guidance of invasive hemodynamic monitoring: A case report

Toxic epidermal necrolysis is a rare immunological disease that is secondary to some medications or upper respiratory infections, with more than 30% involvement of skin and mucosa. Herein, we describe a 7-year-old boy with TEN, heart failure, and sepsis treated with the guidance of an invasive hemodynamic monitoring device.

Toward an Electrical Analog of the Cardiovascular System in Hemorrhage

Current quantitative descriptions of the cardiovascular system in hemorrhagic shock focus on pressure based metrics. This approach is often incomplete; overlooking the important role of tissue perfusion. Electrical analogs to the cardiovascular system may offer a more complete description of hemorrhage. Application of fundamental concepts in electrical circuit theory (i.e.; Kirchhoff's Voltage Law and Ohm's Law) to analogs of the cardiovascular system offers a more refined description of this complex process. This manuscript hopes to serve as a starting point for a more mathematically robust, and clinically relevant description of hemorrhagic shock.

Changes in perfusion can detect changes in the cardiac index in patients with septic shock

Objective

The perfusion index (PI) is usually used to assess peripheral perfusion, which can be influenced by the cardiac index (CI). CI monitoring is often needed during the treatment of patients with shock. We investigated the relationship between changes in the PI (ΔPI) and changes in the CI (ΔCI) in patients with septic shock.

Methods

This retrospective study included patients with septic shock who underwent pulse-induced continuous cardiac output monitoring. We measured the CI and PI before and after fluid loading during the first 6 hours of intensive care unit admission. Fluid responsiveness was defined as a ≥10% ΔCI after fluid loading. Other hemodynamic and oxygen-derived parameters were also collected at the exact time of each CI measurement.

Results

Fifty-five patients were included in the study (29 fluid responders, 26 fluid non-responders). In the univariate analysis, ΔPI was positively correlated with ΔCI. In the multivariable analysis, ΔPI was independently associated with ΔCI. The receiver operating characteristic curve showed that ΔPI was an appropriate marker with which to discriminate a CI increase with an area under the curve of 0.776.

Conclusion

This study showed a positive correlation between ΔPI and ΔCI during the early treatment phase of septic shock.

Updates in Hemodynamic Monitoring: A Review for Pharmacists

Vital signs are regularly monitored in hospitalized patients. In the intensive care unit (ICU), traditional non-invasive blood pressure monitoring and telemetry may not provide enough information to determine the etiology of hemodynamic instability or guide intervention. Arterial catheters remain the gold-standard for continuous blood pressure monitoring and are commonly used in ICU patients. Pulmonary artery catheters and central venous catheters are beneficial in select patient populations and provide more advanced and specific information about a patient's hemodynamics. However, neither are benign and can increase risk of complications such as infection, arrhythmias, pneumothorax and vascular or valvular damage. In the past 10 years, the development of reliable non-invasive (NICOM), or minimally-invasive (MICOM), cardiac output monitoring devices has accelerated. The MICOM devices require an arterial catheter to obtain hemodynamic values, whereas NICOM devices do not require any arterial or venous access. These devices have emerged to be particularly useful in evaluating and managing patients with suspected mixed shock. As these devices become more prevalent, it is imperative that clinical pharmacists become familiar with interpreting this data as it may have a substantial impact on medication selection and optimization. This review will discuss the basics of NICOM and MICOM devices, limitations with these methods of monitoring, and clinical application for pharmacists.

PRO: The pulmonary artery catheter has a paramount role in current clinical practice

Ever since its clinical introduction, the utilization of the pulmonary artery catheter (PAC) has been surrounded by multiple controversies, mostly related to imprecise clinical indications and the complications derived from its placement. Currently, one of the most important criticisms of the PAC is the ambiguity in the interpretation of its hemodynamic measurements and therefore, in the translation of this data into specific therapeutic interventions. The popularity of the PAC stems from the fact that it provides hemodynamic data that cannot be obtained from clinical examination. The assumption is that this information would allow better understanding of the individual's hemodynamic profile which would trigger therapeutic interventions that improve patient outcomes. Nevertheless, even with the current diversity of hemodynamic devices available, the PAC remains a valuable tool in a wide variety of clinical settings. The authors present a review exposing the benefits of the PAC, current clinical recommendations for its use, mortality and survival profile, its role in goal-directed therapy, and other applications of the PAC beyond cardiac surgery and the intensive care unit.

Advances in the Approaches Using Peripheral Perfusion for Monitoring Hemodynamic Status

Measures of peripheral perfusion can be used to assess the hemodynamic status of critically ill patients. By monitoring peripheral perfusion status, clinicians can promptly initiate life-saving therapy and reduce the likelihood of shock-associated death. Historically, abnormal perfusion has been indicated by the observation of pale, cold, and clammy skin with increased capillary refill time. The utility of these assessments has been debated given that clinicians may vary in their clinical interpretation of body temperature and refill time. Considering these constraints, current sepsis bundles suggest the need to revise resuscitation guidelines. New technologies have been developed to calculate capillary refill time in the hopes of identifying a new gold standard for clinical care. These devices measure either light reflected at the surface of the fingertip (reflected light), or light transmitted through the inside of the fingertip (transmitted light). These new technologies may enable clinicians to monitor peripheral perfusion status more accurately and may increase the potential for ubiquitous hemodynamic monitoring across different clinical settings. This review will summarize the different methods available for peripheral perfusion monitoring and will discuss the advantages and disadvantages of each approach.

Predictive value of perfusion index for mortality in mechanically ventilated patients

AIM

This study aimed to examine the prognostic significance of the perfusion index (PI) in mechanically ventilated patients.

METHODS

Study included sixty patients who had the risk factors for the development of acute respiratory distress syndrome and received mechanical ventilator (MV) support in intensive care unit (ICU) unit between January 2017/January 2018. The demographic characteristics, vital signs, blood gas parameters, lactate levels, prognostic scores, and use of inotropic drugs were recorded. Arterial blood gas and PI measurements at the frontal region were performed at the time of and 12th and 24th hours of admission to the ICU. The patients were followed up for 60 days, and the outcome was recorded.

RESULTS

Twelve patients (20%) died during the first 7 days, and 27 patients (45%) died within 60 days of the admission. Multivariate analyses to determine potential predictors of 7 and 30-day mortality showed that only 24th-hour lactate level was independent predictor of 60-day mortality, and the PI at 24th was the sole independent predictor of 7-day mortality.

CONCLUSION

The PI did not predict 60-day mortality in MV patients who had risk factors for the development of Acute Respiratory Distress Syndrome (ARDS). However, the PI at 24th may be a significant predictor of 7-day mortality.

Change in Carotid Blood Flow and Carotid Corrected Flow Time Assessed by Novice Sonologists Fails to Determine Fluid Responsiveness in Spontaneously Breathing Intensive Care Unit Patients

Measurement of carotid blood flow (CBF) and corrected carotid flow time (ccFT) has been proposed as a non-invasive means of determining fluid responsiveness. We evaluated the ability of CBF and ccFT as assessed by novice sonologists to determine fluid responsiveness in intensive care unit patients. Three novice physician sonologists performed carotid ultrasounds before and after a fluid bolus and calculated changes in CBF and ccFT. Fluid responsiveness was defined as a ≥10% increase in cardiac index as measured using bioreactance. Of 112 participants, 56 (50%) were fluid responders. Changes in CBF and ccFT performed poorly at determining fluid responsiveness: 19 mL/min (area under the receiver operating characteristic curve: 0.58, 95% confidence interval: 0.47-0.68) and 6 ms (0.59, 0.46-0.65) respectively. Novice physician sonologists are unable to determine fluid responsiveness using CBF or ccFT. Further research is needed to identify the key limiting factors in using carotid ultrasound to determine fluid responsiveness.

Multimorbidity and Critical Care Neurosurgery: Minimizing Major Perioperative Cardiopulmonary Complications

With increasing prevalence of chronic diseases, multimorbid patients have become commonplace in the neurosurgical intensive care unit (neuro-ICU), offering unique management challenges. By reducing physiological reserve and interacting with one another, chronic comorbidities pose a greatly enhanced risk of major postoperative medical complications, especially cardiopulmonary complications, which ultimately exert a negative impact on neurosurgical outcomes. These premises underscore the importance of perioperative optimization, in turn requiring a thorough preoperative risk stratification, a basic understanding of a multimorbid patient’s deranged physiology and a proper appreciation of the potential of surgery, anesthesia and neurocritical care interventions to exacerbate comorbid pathophysiologies. This knowledge enables neurosurgeons, neuroanesthesiologists and neurointensivists to function with a heightened level of vigilance in the care of these high-risk patients and can inform the perioperative neuro-ICU management with individualized strategies able to minimize the risk of untoward outcomes. This review highlights potential pitfalls in the intra- and postoperative neuro-ICU period, describes common preoperative risk stratification tools and discusses tailored perioperative ICU management strategies in multimorbid neurosurgical patients, with a special focus on approaches geared toward the minimization of postoperative cardiopulmonary complications and unplanned reintubation.

Mangiferin exert cardioprotective and anti-apoptotic effects in heart failure induced rats

Mangiferin is a well-known xanthone extracted from mango leaves (Mangifera indica Linn). Mangiferin is widely distributed in the bark, peel, leaf, seed, stalk, and kernel of mango and higher plants. The pharmacological properties of mangiferin, including its antioxidant, anticancer, antiaging, antiviral, hepatoprotective, analgesic, and immunomodulatory activities, have been described in several studies. We investigated the effect of mangiferin on isoproterenol-induced apoptosis. Experimental heart failure was induced in rats by intraperitoneal administration of isoproterenol (5 mg/kg) for 7 consecutive days. Rats were divided into five groups: group I (sham rats), group II (isoproterenol alone control), group III (isoproterenol + 25 mg/kg mangiferin), group IV (isoproterenol + 50 mg/kg mangiferin), and group V (isoproterenol + 0.0225 mg/kg digitalis as a positive control). Hemodynamic parameters and body weight, heart weight and liver weight, apoptosis induction, and caspase-3, Bax, and Bcl-2 protein levels were measured, and a histopathological analysis of cardiomyocytes was performed. In addition, apoptosis and protein expression of caspase-3, cleaved caspase-3, Bax, and Bcl-2 were measured in cardiac H9c2 cells. Mangiferin supplementation significantly increased heart rate and improved the maximum rate of decrease in left ventricular (LV) pressure, the maximum rate of increase in LV pressure, and LV systolic pressure. Mangiferin reduced inflammatory cell infiltration and the number of broken myocardial fibers, and decreased apoptosis in cardiomyocytes by reducing proteins levels of caspase-3 and Bax and increasing those of Bcl-2. Our findings suggest that mangiferin has a cardioprotective effect against isoproterenol-induced apoptosis in cardiomyocytes.

Vasopressors and Nutrition Therapy: Safe Dose for the Outset of Enteral Nutrition?

Background and Aims

Patients with hemodynamic instability need to receive intensive treatment as fluid replacement and vasoactive drugs. In the meantime, it is supposed to initiate nutritional therapy within 24 to 48 hours after admission to the intensive care unit (ICU), as an essential part of patient's intensive care and better outcomes. However, there are many controversies tangential to the prescription of enteral nutrition (EN) concomitant to the use of vasopressor and its doses. In this way, the present study aimed to identify what the literature presents of evidence to guide the clinical practice concerning the safe dose of vasopressors for the initiation of nutritional therapy in critically ill patients.

Methods

This review was carried out in PubMed, ProQuest, Web of Science, and Medline databases. The descriptors were used to perform the search strategy: Critical Care, Intensive Care Units, Vasoconstrictor Agents, and Enteral Nutrition. Inclusion criteria were patients of both genders, over 18 years of age, using vasoactive drugs, with the possibility of receiving EN therapy, and articles written in English, Portuguese, and Spanish. In addition, exclusion criteria were case reports, non-papers, and repeated papers.

Results

10 articles met our inclusion criteria.

Conclusion

It was observed that there are many controversies about the supply of EN in critically ill patients using vasopressor, especially about the safe dose, and it was not possible to identify a cutoff value for the beginning therapy. Despite the drug doses, clinical signs are still the most important parameters in the evaluation of EN tolerance.

Noninvasive Cardiac Output and Central Systolic Pressure From Cuff-Pressure and Pulse Wave Velocity

GOAL

We introduce a novel approach to estimate cardiac output (CO) and central systolic blood pressure (cSBP) from noninvasive measurements of peripheral cuff-pressure and carotid-to-femoral pulse wave velocity (cf-PWV).

METHODS

The adjustment of a previously validated one-dimensional arterial tree model is achieved via an optimization process. In the optimization loop, compliance and resistance of the generic arterial tree model as well as aortic flow are adjusted so that simulated brachial systolic and diastolic pressures and cf-PWV converge towards the measured brachial systolic and diastolic pressures and cf-PWV. The process is repeated until full convergence in terms of both brachial pressures and cf-PWV is reached. To assess the accuracy of the proposed framework, we implemented the algorithm on in vivo anonymized data from 20 subjects and compared the method-derived estimates of CO and cSBP to patient-specific measurements obtained with Mobil-O-Graph apparatus (central pressure) and two-dimensional transthoracic echocardiography (aortic blood flow).

RESULTS

Both CO and cSBP estimates were found to be in good agreement with the reference values achieving an RMSE of 0.36 L/min and 2.46 mmHg, respectively. Low biases were reported, namely -0.04 ± 0.36 L/min for CO predictions and -0.27 ± 2.51 mmHg for cSBP predictions.

SIGNIFICANCE

Our one-dimensional model can be successfully "tuned" to partially patient-specific standards by using noninvasive, easily obtained peripheral measurement data. The in vivo evaluation demonstrated that this method can potentially be used to obtain central aortic hemodynamic parameters in a noninvasive and accurate way.

Performance of a 25% Inferior Vena Cava Collapsibility in Detecting Fluid Responsiveness When Assessed by Novice Versus Expert Physician Sonologists

OBJECTIVES

Inferior vena cava collapsibility (cIVC) measured by point-of-care ultrasound (POCUS) has been proposed as a noninvasive means of assessing fluid responsiveness. We aimed to prospectively evaluate the performance of a 25% cIVC cutoff value to detect fluid responsiveness among spontaneously breathing intensive care unit (ICU) patients when assessed with POCUS by novice versus expert physician sonologists.

METHODS

Prospective observational study of spontaneously breathing ICU patients. Fluid responsiveness was defined as a >10% increase in cardiac index following a 500 mL fluid bolus, measured by bioreactance. Novice sonologist measured cIVC with POCUS. Their measurements were later compared to an expert physician sonologist who independently reviewed the POCUS images and assessed cIVCs.

RESULTS

Of the 85 participants, 44 (52%) were fluid responders. A 25% cIVC cutoff value performed better when assessed by expert sonologists than novice physician sonologists (receiver-operator characteristic curve, ROC = 0.82 [0.74-0.88] vs ROC = 0.69 [0.60-0.77]).

CONCLUSIONS

A 25% cIVC cutoff value measured by POCUS detects fluid responsiveness. However, the experience of the physician sonologist affects test performance and should be considered when interpreting and clinically using cIVC to direct intravenous fluid resuscitation.

Accuracy of non-invasive and minimally invasive hemodynamic monitoring: where do we stand?

One of the most important variables in assessing hemodynamic status in the intensive care unit (ICU) is the cardiac function and blood pressure. Invasive methods such as pulmonary artery catheter and arterial line allow monitoring of blood pressure and cardiac function accurately and reliably. However, their use is not without drawbacks, especially when the invasive nature of these procedures and complications associated with them are considered. There are several newer methods of noninvasive and minimally invasive hemodynamic monitoring available. In this manuscript, we will review these different methods of minimally invasive and non-invasive hemodynamic monitoring and will discuss their advantages, drawbacks and limitations.

Management of Sepsis in Patients With Cirrhosis: Current Evidence and Practical Approach

Sepsis in patients with cirrhosis is associated with high mortality. An impaired immune response accounts for the increased infection risk observed in these patients. Hemodynamic and systemic changes suggestive of sepsis may be observed in patients with cirrhosis in the absence of infection; therefore, diagnosis and treatment of sepsis may be delayed. The optimal management of the critically ill patient with sepsis and cirrhosis has not been well established and is generally extrapolated from consensus guidelines and expert recommendations made for management of patients without cirrhosis with sepsis. Despite the lack of strong evidence, we propose a contemporary pragmatic approach to sepsis management in patients with cirrhosis, including the choice of fluids, vasopressors, and antibiotics.

Calibrated cardiac output monitoring versus standard care for fluid management in the shocked ICU patient: a pilot randomised controlled trial

Background

Despite the evidence for calibrated cardiac monitored devices to determine fluid responsiveness, there is minimal evidence that the use of cardiac output monitor devices leads to an overall change in IV fluid use. We sought to investigate the feasibility of performing a randomised controlled study using calibrated cardiac output monitoring devices in shocked ICU patients and whether the use of these devices led to a difference in total volume of IV fluid administered.

Methods

We performed a single-centre non-blinded randomised controlled study which included patients who met the clinical criteria for shock on admission to ICU. Patients were divided into two groups (cardiac output monitors or standard) by block randomisation. Patients allocated to the cardiac output monitor all received EV1000 with Volume View sets. Daily intravenous fluid administration and cumulative fluid balance was recorded for 3 days. The primary outcome assessed was the difference in daily intravenous fluid administration and cumulative fluid balance at 72 h between the two groups. We also assessed how often the clinicians used the cardiac monitor to guide fluid therapy and the different reasoning for initiating further intravenous fluids.

Results

Eighty patients were randomised and 37 received calibrated cardiac output monitors. We found no adverse outcomes in the use of calibrated cardiac output monitoring devices and that was feasible to perform a randomised controlled trial. There was no significant difference between the standard care group vs the cardiac monitoring group for cumulative fluid balance (2503 ± 3764 ml vs 2458 ± 3560 ml, p = 0.96). There was no significant difference between the groups for daily intravenous fluid administration on days 1, 2 or 3. In the cardiac monitored group, only 43% of the time was the EV1000 output incorporated into the decision to give further intravenous fluids.

Conclusion

It is feasible to perform a randomised controlled trial using calibrated cardiac output monitoring devices. In addition, there was no trend to suggest that the use of a cardiac monitors leads to lower IV fluid use in the shocked patient. Further trials will require study designs to optimise the use of a cardiac output monitor to determine the utility of these devices in the shocked patient.

Trial registration

ANZCTR, ACTRN12618001373268. Registered 15 August 2018-retrospectively registered.

Utility of transpulmonary thermodilution with Pulse Index Continuous Cardiac Output system for hemodynamic assessment in a hemodialysis patient with arteriovenous fistula and continuous renal replacement therapy: A case report

Close hemodynamic monitoring is crucial for the patients to guide cardiovascular therapy for the optimal management. Transpulmonary thermodilution offers a less invasive hemodynamic monitoring with Pulse Index Continuous Cardiac Output system analysis. Intracardiac shunts have been associated with well-defined alterations in transpulmonary thermodilution-related hemodynamic parameters leading to inaccurate measurements and therefore are among the contraindications for transpulmonary thermodilution. However, data on the effects of arteriovenous fistulas as well as extracorporeal circuits on the thermodilution curves remain limited and inconclusive. Herein, we report generation of modified thermodilution curve forms leading to incorrect calculation of thermodilution-derived hemodynamic parameters by Pulse Index Continuous Cardiac Output system in a female patient in the presence of Continuous Veno-Venous Hemodiafiltration and a high flow arteriovenous fistula. Our findings revealed generation of modified thermodilution curves and unacceptably high extravascular lung water readings by Pulse Index Continuous Cardiac Output system. This seems consistent with early recirculation of cold indicator in case of a peripheral shunt emphasizing the potential impact of high flow arteriovenous fistula on reliability of transpulmonary thermodilution measurements in critically ill patients, limiting the use of Pulse Index Continuous Cardiac Output system in these conditions.

Hemodynamic early goal-directed therapy: Explaining the fine print

The management of patients after cardiothoracic surgery can be very complex. Variabilities exist in hemodynamic status after cardiac surgery and the use of cardiopulmonary bypass – all of which can have a significant impact on myocardial Frank–Starling curves. Typically, invasive monitoring with pulmonary artery catheters is used to assess the complex physiology that these patients experience in the perioperative setting. However, the use of invasive monitoring is not without risk, and the broader benefits are poorly defined. Furthermore, there is growing evidence to support the use of hemodynamic early goal-directed therapy to optimize outcomes in critically ill patients. The purpose of this editorial statement is the review of some of the current literature with regards to the utility of goal-directed therapy as applied to the postoperative cardiac surgical patient.