What's new in ultrasound-based assessment of organ perfusion in the critically ill: expanding the bedside clinical monitoring window for hypoperfusion in shock

Cardiogenic shock diagnosis and management in general intensive care: a nationwide survey

BACKGROUND

the epidemiology of cardiogenic shock has evolved over the years: in the last decades an increasing prevalence of cardiogenic shock related to acute decompensated heart failure was observed. Therefore, treatment bundles should be updated according to the underlying pathophysiology. No data exist regarding the diagnostic/therapeutic strategies in general intensive care units.

METHODS

A 27-questions survey was spread through the GiViTi (Italian Group for the Evaluation of Interventions in Intensive Care Medicine). The results were then divided according to level of hospitals (1st-2nd versus 3rd).

RESULTS

Sixty-nine general intensive care units replied to the survey. The shock team is present in 13% of institutions; Society for Cardiovascular Angiography and Interventions shock classification is applied only in 18.8%. Among the ICUs, 94.2% routinely use a cardiac output monitoring device (pulmonary artery catheter more frequently in 3rd level centers). The first-line adrenergic drug are vasopressors in 27.5%, inotrope in 21.7% or their combination in 50.7%; 79.7% applies fluid challenge. The first vasopressor of choice is norepinephrine (95.7%) (maximum dosage tolerated higher than 0.5 mcg/kg/min in 29%); the first line inotrope is dobutamine (52.2%), followed by epinephrine in 36.2%. The most frequently used mechanical circulatory supports are intra-aortic balloon pump (71%), Impella (34.8%) and VA-ECMO (33.3%); VA-ECMO is the first line strategy in refractory cardiogenic shock (60.8%).

CONCLUSIONS

According to this survey, there is no standardized approach to cardiogenic shock amongst Italian general intensive care units. The application of shock severity stratification and the treatment bundles may play a key role in improving the outcome.

Improving Patient Outcomes in Abdominal Surgery

Post-operative acute kidney injury (PO-AKI) is a frequent complication described in 15% of non-cardiac surgeries, 30% of cardiac surgeries, and 52% of patients requiring intensive post-operative care [...].

Clinical relevance and prognostic value of renal Doppler in acute decompensated precapillary pulmonary hypertension

AIMS

We aim to evaluate the clinical relevance and the prognostic value of arterial and venous renal Doppler in acute decompensated precapillary pulmonary hypertension (PH).

METHODS AND RESULTS

The renal resistance index (RRI) and the Doppler-derived renal venous stasis index (RVSI) were monitored at admission and on Day 3 in a prospective cohort of precapillary PH patients managed in intensive care unit for acute right heart failure (RHF). The primary composite endpoint included death, circulatory assistance, urgent transplantation, or rehospitalization for acute RHF within 90 days following inclusion. Ninety-one patients were enrolled (58% female, age 58 ± 16 years). The primary endpoint event occurred in 32 patients (33%). In univariate logistic regression analysis, variables associated with RRI higher than the median value were non-variable parameters (age and history of hypertension), congestion (right atrial pressure and renal pulse pressure), cardiac function [tricuspid annular plane systolic excursion (TAPSE) and left ventricular outflow tract- velocity time integral], systemic pressures and NT-proBNP. Variables associated with RVSI higher than the median value were congestion (high central venous pressure, right atrial pressure, and renal pulse pressure), right cardiac function (TAPSE), severe tricuspid regurgitation, and systemic pressures. Inotropic support was more frequently required in patients with high RRI (P = 0.01) or high RVSI (P = 0.003) at the time of admission. At Day 3, a RRI value <0.9 was associated with a better prognosis after adjusting to the estimated glomerular filtration rate.

CONCLUSION

Renal Doppler provides additional information to assess the severity of patients admitted to the intensive care unit for acute decompensated precapillary PH.

Perioperative Renal Ultrasonography of Arterio-to-Venous Coupling Predicts Postoperative Complications after Major Laparoscopic Urologic Surgery

Point-of-care ultrasonography (POCUS) with concomitant venous and arterial Doppler assessment enables clinicians to assess organ-specific blood supply. To date, no studies have investigated the usefulness of including a comprehensive perioperative POCUS assessment of patients undergoing major laparoscopic surgery. The primary aim of the present study was to evaluate whether the combined venous and arterial renal flow evaluation, measured at different time points of perioperative period, may represent a clinically useful non-invasive method to predict postoperative acute kidney injury (AKI) after major laparoscopic urologic surgery. The secondary outcome was represented by the development of any postoperative complication at day 7. We included 173 patients, subsequently divided for analysis depending on whether they did (n = 55) or did not (n = 118) develop postoperative AKI or any complications within the first 7 days. The main results of the present study were that: (1) the combination of arterial hypoperfusion and moderate-to-severe venous congestion inferred by POCUS were associated with worst outcomes (respectively, HR: 2.993, 95% CI: 1.522-5.884 and HR: 8.124, 95% CI: 3.542-18, p < 0.001); (2) high intra-operative abdominal pressure represents the only independent determinant of postoperative severe venous congestion (OR: 1.354, 95% CI: 1.017-1.804, p = 0.038); (3) the overall number of complications relies on the balance between arterial inflow and venous outflow in order to ensure the adequacy of peripheral perfusion; and (4) the overall reliability of splanchnic perfusion assessment by Doppler is high with a strong inter-rater reliability (ICC: 0.844, 95% CI: 0.792-0.844). The concomitant assessment of arterial and venous Doppler patterns predicts postoperative complications after major laparoscopic urologic surgery and may be considered a useful ultrasonographic biomarker to stratify vulnerable patients at risk for development of postoperative complications.

Kidney Injury in Critically Ill Patients with COVID-19 - From Pathophysiological Mechanisms to a Personalized Therapeutic Model

Acute kidney injury is a common complication of COVID-19, frequently fuelled by a complex interplay of factors. These include tubular injury and three primary drivers of cardiocirculatory instability: heart-lung interaction abnormalities, myocardial damage, and disturbances in fluid balance. Further complicating this dynamic, renal vulnerability to a "second-hit" injury, like a SARS-CoV-2 infection, is heightened by advanced age, chronic kidney disease, cardiovascular diseases, and diabetes mellitus. Moreover, the influence of chronic treatment protocols, which may constrain the compensatory intrarenal hemodynamic mechanisms, warrants equal consideration. COVID-19-associated acute kidney injury not only escalates mortality rates but also significantly affects long-term kidney function recovery, particularly in severe instances. Thus, the imperative lies in developing and applying therapeutic strategies capable of warding off acute kidney injury and decelerating the transition into chronic kidney disease after an acute event. This narrative review aims to proffer a flexible diagnostic and therapeutic strategy that recognizes the multi-faceted nature of COVID-19-associated acute kidney injury in critically ill patients and underlines the crucial role of a tailored, overarching hemodynamic and respiratory framework in managing this complex clinical condition.

Fluids and vasopressors in septic shock: basic knowledge for a first approach in the emergency department

Much research, both pathophysiological and clinical, has been produced about septic shock during the last 20 years. Nevertheless, many aspects of treatment are still controversial, among these the approach to the administration of fluids and vasopressors. After the first clinical trial on Early goal-directed therapy (EGDT) was published, a liberal approach to the use of fluids and conservative use of vasopressors prevailed, but in recent years a more restrictive use of fluids and an earlier introduction of vasopressors seem to be preferred. Although both treatments are based on sound pathophysiological knowledge,  clinical evidence is still inadequate and somehow controversial.  In this non-systematic review, recent research on the hemodynamics of septic shock and its treatment with fluids and inotropes is discussed. As a conclusion, general indications are proposed for a practical approach to patients in septic shock.

Inferior Vena Cava Ultrasonography for Volume Status Evaluation: An Intriguing Promise Never Fulfilled

The correct determination of volume status is a fundamental component of clinical evaluation as both hypovolaemia (with hypoperfusion) and hypervolaemia (with fluid overload) increase morbidity and mortality in critically ill patients. As inferior vena cava (IVC) accounts for two-thirds of systemic venous return, it has been proposed as a marker of volaemic status by indirect assessment of central venous pressure or fluid responsiveness. Although ultrasonographic evaluation of IVC is relatively easy to perform, correct interpretation of the results may not be that simple and multiple pitfalls hamper its wider application in the clinical setting. In the present review, the basic elements of the pathophysiology of IVC behaviour, potential applications and limitations of its evaluation are discussed.

Electrocardiographic Time-Intervals Waveforms as Potential Predictors for Severe Acute Kidney Injury in Critically Ill Patients

Background: Acute kidney injury (AKI) is common in critically ill patients admitted to intensive care units (ICU) and is frequently associated with poorer outcomes. Hence, if an indicator is available for predicting severe AKI within the first few hours of admission, management strategies can be put into place to improve outcomes. Materials and methods: This was a prospective, observational study, involving 63 critically ill patients, that aimed to explore the diagnostic accuracy of different Doppler parameters in predicting AKI in critically ill patients from a mixed ICU. Participants were enrolled at ICU admission. All underwent ultrasonographic examinations and hemodynamic assessment. Renal Doppler resistive index (RDRI), venous impedance index (VII), arterial systolic time intervals (a-STI), and venous systolic time intervals (v-STI) were measured within 2 h from ICU admission. Results: Cox proportional hazards models, including a-STI, v-STI, VII, and RDRI as independent variables, returned a-STI as the only putative predictor for the development of AKI or severe AKI. An overall statistically significant difference (p < 0.001) was observed in the Kaplan−Meier plots for cumulative AKI events between patients with a-STI higher or equal than 0.37 and for cumulative severe AKI-3 between patients with a-STI higher or equal than 0.63. As assessed by the area under the receiver operating curves (ROC) curves, a-STI performed best in diagnosing any AKI and/or severe AKI-3. Positive correlations were found between a-STI and the N-terminal brain natriuretic peptide precursor (NT-pro BNP) (ρ = 0.442, p < 0.001), the sequential organ failure assessment (SOFA) score (ρ: 0.361, p = 0.004), and baseline serum creatinine (ρ: 0.529, p < 0.001). Conclusions: Critically ill patients who developed AKI had statistically significant different a-STI (on admission to ICU), v-STI, and VII than those who did not. Moreover, a-STI was associated with the development of AKI at day 5 and provided the best diagnostic accuracy for the diagnosis of any AKI or severe AKI compared with RDRI, VII, and v-STI.

Elevated pulsatility index of the superior mesenteric artery indicated prolonged mechanical ventilation in patients after cardiac valve surgery

Purpose

This study examined whether alterations in Doppler parameters of superior mesenteric artery (SMA) are associated with prolonged mechanical ventilation (PMV) in patients who underwent cardiac valve surgery.

Methods

Hemodynamic and SMA Doppler parameters were collected at intensive care unit(ICU) admission. The duration of mechanical ventilation was monitored. PMV was defined as mechanical ventilation ≥96 h.

Results

A total of 132 patients admitted to ICU after cardiac valve surgery were evaluated for enrollment, of whom 105 were included. Patients were assigned to the control (n = 63) and PMV (n = 42) groups according to the mechanical ventilation duration. The pulsatility index(SMA-PI) and resistive index of SMA (SMA-RI) were 3.97 ± 0.77 and 0.88 (0.84-0.90) in the PMV group after cardiac valve surgery, which was lower than the SMA-PI (2.95 ± 0.71, p < 0.0001) and SMA-RI of controls (0.8, 0.77-0.88, p < 0.0001). SMA-PI at admission had favorable prognostic significance for PMV (AUC = 0.837, p < 0.0001).

Conclusions

An elevated SMA-PI is common in patients after cardiac valve surgery with PMV. Increased SMA-PI could help predict PMV after cardiac valve surgery. Using point-of-care ultrasound to measure SMA-PI at ICU admission is an acceptable and reproducible method for identifying patients with PMV.

Construction and efficacy evaluation of an early warning scoring system for septic shock in patients with digestive tract perforation: A retrospective cohort study

Objective

To establish an early warning scoring system for septic shock in patients with digestive tract perforation (DTP) and evaluate its diagnostic efficacy.

Methods

Patients with surgically confirmed or clinically diagnosed DTP admitted to the Department of Intensive Care Medicine of Fujian Provincial Hospital from June 2012 to October 2021 were retrospectively analyzed. General demographic characteristics, perforation-related information, vital signs, common laboratory indicators, and common ICU scores (Glasgow Coma Scale score, Acute Physiology and Chronic Health Evaluation-II score,Sequential Organ Failure Assessment score) were collected. The patients were divided into shock group and non-shock group according to whether the patients had septic shock during hospitalization. The risk factors of septic shock were screened by basic statistical analysis and multivariate Logistic regression analysis. The receiver operating characteristic curve was drawn to determine the cut-off value of the continuous indicators and discretized with reference to clinic, and the corresponding score was set according to the β regression coefficient of each variable.

Results

A total of 176 patients with DTP were included. The average age of the patients was 64.13 ± 14.67 years old, and 74.40% were males. The incidence of septic shock was 30.11% (53/176). Multivariate Logistic regression analysis showed that the highest heart rate≥105 beats/min, Glasgow Coma Scale score≤14 points, lactic acid≥5.75 mmol/L, procalcitonin≥41.47 ug/L, C-reactive protein≥222.5 mg/L were independent risk factors for septic shock in patients with DTP. The total score of clinical diagnostic scoring system of septic shock in patients with DTP was 6 points, including the highest heart rate≥105 beats/min (1 point), lactic acid≥5.75 mmol/L (two points), procalcitonin≥41.47 ug/L (one point), C-reactive protein≥222.5 mg/L (1 point), and Glasgow Coma Scale score≤14 points (1 point). The area under ROC curve (AUC) of this scoring system was 0.789 and the 95% confidence interval was 0.717–0.860 (P &lt; 0.001); when the optimal cut-off value was 2.5, the sensitivity and specificity were 54.70 and 87.80%, respectively.

Conclusion

This new score system has its certain clinical value and has important guiding significance for clinicians to judge the prognosis of patients with DTP in time.

Visual Rounds Based on Multiorgan Point-of-Care Ultrasound in the ICU

Point-of-care ultrasonography (POCUS) is performed by a treating clinician at the patient's bedside, provides a acquisition, interpretation, and immediate clinical integration based on ultrasonographic imaging. The use of POCUS is not limited to one specialty, protocol, or organ system. POCUS provides the treating clinician with real-time diagnostic and monitoring information. Visual rounds based on multiorgan POCUS act as an initiative to improve clinical practice in the Intensive Care Unit and are urgently needed as part of routine clinical practice.

Renal Resistive Index on Intensive Care Unit Admission Correlates With Tissue Hypoperfusion Indices and Predicts Clinical Outcome

BACKGROUND

Renal resistive index (RRI) has been used to evaluate renal blood flow. Our aim was to investigate the relation between RRI and global tissue hypoperfusion indices and their association with clinical outcome, in intensive care unit (ICU) patients.

METHODS

RRI was measured within 24 h of ICU admission. Gas exchange and routine hemodynamic variables at the time of RRI assessment were recorded. An elevated RRI was defined as >0.7. The ratio of central venous-to-arterial carbon dioxide partial pressure difference by arterial-to-central venous oxygen content difference (P(cv-a)CO2/C(a-cv)O2) and lactate were used as global tissue hypoperfusion indices.

RESULTS

A total of 126 patients were included [median age 61 (IQR 28) years, 74% males]. P(cv-a)CO2/C(a-cv)O2 ratio and arterial lactate were significantly higher in patients with RRI >0.7 compared with those with RRI ≤0.7 [2.88 (3.39) vs. 0.62 (0.57) mmol/L and 2.4 (2.2) vs. 1.2 (0.6)] respectively, both P < 0.001)]. RRI was significantly correlated with P(cv-a)CO2/C(a-cv)O2 ratio and arterial lactate for the whole patient population (rho = 0.64, both P < 0.0001) and for the subset of patients with shock (rho = 0.47, P = 0.001; and r = 0.64, P < 0.0001 respectively). Logistic regression models showed a significant association between RRI and P(cv-a)CO2/C(a-cv)O2 ratio with clinical outcome. The combination of RRI with P(cv-a)CO2)/(C(a-cv)O2 ratio and lactate better predicted mortality than RRI alone [AUC 84.8% (95% CI 5.1% -94.4%)] vs. [AUC 74.9% (95% CI 61%-88.8%)] respectively, P < 0.001.

CONCLUSIONS

Renal blood flow assessed by RRI, on ICU admission, correlates with global tissue hypoperfusion indices. In addition, RRI in combination with tissue perfusion estimation better predicts clinical outcome than RRI alone.

Constrictive pericarditis: portal, splenic, and femoral venous Doppler pulsatility: a case series

PURPOSE

Pulsatile flow of the portal vein has been implicated as an indicator of right ventricular dysfunction in cardiac patients. In patients with significantly elevated right atrial pressure, pulsatile venous flow may be transmitted to the portal, splenic, renal, and femoral veins. We describe the evolution of these echocardiographic findings in four patients with constrictive pericarditis (CP) undergoing pericardiectomy with simultaneous hemodynamic waveform and cerebral oximetry monitoring in the operating room and in the intensive care unit.

CLINICAL FEATURES

Patient 1 presented classic signs of CP, including equalization of left and right diastolic pressures, a "square root" sign on the diastolic portion of the right ventricular pressure curve, and elevated right atrial pressure. Preoperative transesophageal echocardiography showed a hyperdynamic left ventricle and dilated right ventricle with abnormal pulsatile waveforms in the portal and splenic veins. Surgical decompression of the pericardium gradually normalized the Doppler waveforms. Increased venous return following pericardiectomy during surgery in patients 2 and 3 and during the postoperative period in patient 4 resulted in right ventricular (RV) failure due to significantly increased preload. Venous pulsatility was also observed in the portal, splenic, and femoral veins.

CONCLUSION

In patients with CP, changes in hemodynamic and echocardiographic signs of RV dysfunction are rapidly reflected by changes in peripheral venous velocities. Identifying signs of splanchnic and peripheral vascular venous congestion could help identify patients at higher risk of developing postoperative complications following pericardiectomy.

Hemodynamic Monitoring in Sepsis-A Conceptual Framework of Macro- and Microcirculatory Alterations

Circulatory failure in sepsis is common and places a considerable burden on healthcare systems. It is associated with an increased likelihood of mortality, and timely recognition is a prerequisite to ensure optimum results. While there is consensus that aggressive source control, adequate antimicrobial therapy and hemodynamic management constitute crucial determinants of outcome, discussion remains about the best way to achieve each of these core principles. Sound cardiovascular support rests on tailored fluid resuscitation and vasopressor therapy. To this end, an overarching framework to improve cardiovascular dynamics has been a recurring theme in modern critical care. The object of this review is to examine the nature of one such framework that acknowledges the growing importance of adaptive hemodynamic support combining macro- and microhemodynamic variables to produce adequate tissue perfusion.

Renal resistive index is associated with acute kidney injury in COVID-19 patients treated in the intensive care unit

Background

Renal resistive index (RRI) is a promising tool for the assessment of acute kidney injury (AKI) in critically ill patients in general, but its role and association to AKI among patients with Coronavirus disease 2019 (COVID-19) is not known.

Objective

The aim of this study was to describe the pattern of RRI in relation to AKI in patients with COVID-19 treated in the intensive care unit.

Methods

In this observational cohort study, RRI was measured in COVID-19 patients in six intensive care units at two sites of a Swedish University Hospital. AKI was defined by the creatinine criteria in the Kidney Disease Improving Global Outcomes classification. We investigated the association between RRI and AKI diagnosis, different AKI stages and urine output.

Results

RRI was measured in 51 patients, of which 23 patients (45%) had AKI at the time of measurement. Median RRI in patients with AKI was 0.80 (IQR 0.71–0.85) compared to 0.72 (IQR 0.67–0.78) in patients without AKI (p = 0.004). Compared to patients without AKI, RRI was higher in patients with AKI stage 3 (median 0.83, IQR 0.71–0.85, p = 0.006) but not in patients with AKI stage 1 (median 0.76, IQR 0.71–0.83, p = 0.347) or AKI stage 2 (median 0.79, min/max 0.79/0.80, n = 2, p = 0.134). RRI was higher in patients with an ongoing AKI episode compared to patients who never developed AKI (median 0.72, IQR 0.69–0.78, p = 0.015) or patients who developed AKI but had recovered at the time of measurement (median 0.68, IQR 0.67–0.81, p = 0.021). Oliguric patients had higher RRI (median 0.84, IQR 0.83–0.85) compared to non-oliguric patients (median 0.74, IQR 0.69–0.81) (p = 0.009). After multivariable adjustment, RRI was independently associated with AKI (OR for 0.01 increments of RRI 1.22, 95% CI 1.07–1.41).

Conclusions

Critically ill COVID-19 patients with AKI have higher RRI compared to those without AKI, and elevated RRI may have a role in identifying severe and oliguric AKI at the bedside in these patients.