Assessing Extravascular Lung Water With Ultrasound: A Tool to Individualize Fluid Management?

Assessment of Extravascular Lung Water Using Lung Ultrasound in Critically Ill Patients Admitted to Intensive Care Unit

Background

Lung ultrasound (LUS) is a simple bedside tool to assess overhydration. Our study aimed to assess extravascular lung water (EVLW) using B-lines and correlate it with weaning, duration of mechanical ventilation, and mortality in critically ill patients admitted to the intensive care unit (ICU).

Patients and methods

150 mechanically ventilated ICU patients prospectively observed over 18 months, with their demographic and clinical data noted. Extravascular lung water was monitored using LUS in four intercostal spaces (ICS) from day 1 to day 5, day 7, day 10, and weekly thereafter. Pulmonary fluid burden was graded as low (1-10), moderate (11-20), and high (21-32). Weaning outcome, duration of weaning, mechanical ventilation, ICU stay, and mortality were compared in patients with and without EVLW.

Results

Out of 150, 54 patients (36.0%) had EVLW. The mean lung score amongst our patients was 8.57 ± 6.0. The mean time for detection of EVLW was 1.43 ± 2.24 days. Lung score was low in 40 (26.67%) patients, moderate in 9 (6.00%) patients, and high in 5 (3.33%) patients. Incidence of weaning failure (p-value = 0.006), duration of weaning, mechanical ventilation, ICU stay (p-value < 0.0001 each), and overall mortality were significantly higher in patients with EVLW (p-value = 0.006).

Conclusion

We conclude that a good proportion of critically ill patients have EVLW. Extravascular lung water significantly increases the duration of weaning, mechanical ventilation days, ICU stay, and overall mortality in critically ill patients.

How to cite this article

Rajpal M, Talwar V, Krishna B, Mustafi SM. Assessment of Extravascular Lung Water Using Lung Ultrasound in Critically Ill Patients Admitted to Intensive Care Unit. Indian J Crit Care Med 2024;28(2):165-169.

Effect of lung ultrasound-guided fluid deresuscitation on duration of ventilation in intensive care unit patients (CONFIDENCE): protocol for a multicentre randomised controlled trial

BACKGROUND

Fluid therapy is a common intervention in critically ill patients. It is increasingly recognised that deresuscitation is an essential part of fluid therapy and delayed deresuscitation is associated with longer invasive ventilation and length of intensive care unit (ICU) stay. However, optimal timing and rate of deresuscitation remain unclear. Lung ultrasound (LUS) may be used to identify fluid overload. We hypothesise that daily LUS-guided deresuscitation is superior to deresuscitation without LUS in critically ill patients expected to undergo invasive ventilation for more than 24 h in terms of ventilator free-days and being alive at day 28.

METHODS

The "effect of lung ultrasound-guided fluid deresuscitation on duration of ventilation in intensive care unit patients" (CONFIDENCE) is a national, multicentre, open-label, randomised controlled trial (RCT) in adult critically ill patients that are expected to be invasively ventilated for at least 24 h. Patients with conditions that preclude a negative fluid balance or LUS examination are excluded. CONFIDENCE will operate in 10 ICUs in the Netherlands and enrol 1000 patients. After hemodynamic stabilisation, patients assigned to the intervention will receive daily LUS with fluid balance recommendations. Subjects in the control arm are deresuscitated at the physician's discretion without the use of LUS. The primary endpoint is the number of ventilator-free days and being alive at day 28. Secondary endpoints include the duration of invasive ventilation; 28-day mortality; 90-day mortality; ICU, in hospital and total length of stay; cumulative fluid balance on days 1-7 after randomisation and on days 1-7 after start of LUS examination; mean serum lactate on days 1-7; the incidence of reintubations, chest drain placement, atrial fibrillation, kidney injury (KDIGO stadium ≥ 2) and hypernatremia; the use of invasive hemodynamic monitoring, and chest-X-ray; and quality of life at day 28.

DISCUSSION

The CONFIDENCE trial is the first RCT comparing the effect of LUS-guided deresuscitation to routine care in invasively ventilated ICU patients. If proven effective, LUS-guided deresuscitation could improve outcomes in some of the most vulnerable and resource-intensive patients in a manner that is non-invasive, easy to perform, and well-implementable.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05188092. Registered since January 12, 2022.

Ultrasound in Sepsis and Septic Shock-From Diagnosis to Treatment

Sepsis and septic shock are among the leading causes of in-hospital mortality worldwide, causing a considerable burden for healthcare. The early identification of sepsis as well as the individuation of the septic focus is pivotal, followed by the prompt initiation of antibiotic therapy, appropriate source control as well as adequate hemodynamic resuscitation. For years now, both emergency department (ED) doctors and intensivists have used ultrasound as an adjunctive tool for the correct diagnosis and treatment of these patients. Our aim was to better understand the state-of-the art role of ultrasound in the diagnosis and treatment of sepsis and septic shock.

METHODS

We conducted an extensive literature search about the topic and reported on the data from the most significant papers over the last 20 years.

RESULTS

We divided each article by topic and exposed the results accordingly, identifying four main aspects: sepsis diagnosis, source control and procedure, fluid resuscitation and hemodynamic optimization, and echocardiography in septic cardiomyopathy.

CONCLUSION

The use of ultrasound throughout the process of the diagnosis and treatment of sepsis and septic shock provides the clinician with an adjunctive tool to better characterize patients and ensure early, aggressive, as well as individualized therapy, when needed. More data are needed to conclude that the use of ultrasound might improve survival in this subset of patients.

Ultrasound during the COVID-19 Pandemic: A Global Approach

SARS-CoV-2 (severe acute respiratory syndrome Coronavirus-2) rapidly spread worldwide as COVID-19 (Coronavirus disease 2019), causing a costly and deadly pandemic. Different pulmonary manifestations represent this syndrome's most common clinical manifestations, together with the cardiovascular complications frequently observed in these patients. Ultrasound (US) evaluations of the lungs, heart, and lower limbs may be helpful in the diagnosis, follow-up, and prognosis of patients with COVID-19. Moreover, POCUS (point-of-care ultrasound) protocols are particularly useful for patients admitted to intensive care units. The present review aimed to highlight the clinical conditions during the SARS-CoV-2 pandemic in which the US represents a crucial diagnostic tool.

Update on the use of ultrasound in the diagnosis and monitoring of the critical patient

Hemodynamic and respiratory complications are the main causes of morbidity and mortality in in critical care units (CCU). Imaging techniques are a key tool in differential diagnosis and treatment. In the last decade, ultrasound has shown great potential for bedside diagnosis of respiratory disease, as well as for the hemodynamic assessment of critically ill patients. Ultrasound has proven to be a useful guide for identifying the type of shock, estimating cardiac output, guiding fluid therapy and vasoactive drugs, providing security in the performance of percutaneous techniques (thoracentesis, pericardiocentesis, evacuation of abscesses/hematomas), detecting dynamically in real time pulmonary atelectasis and its response to alveolar recruitment maneuvers, and predicting weaning failure from mechanical ventilation. Due to its dynamic nature, simple learning curve and absence of ionizing radiation, it has been incorporated as an essential tool in daily clinical practice in CCUs. The objective of this review is to offer a global vision of the role of ultrasound and its applications in the critically ill patient.

Lung ultrasound-guided treatment for heart failure: An updated meta-analysis and trial sequential analysis

Background

The usefulness of lung ultrasound (LUS) in guiding heart failure (HF) treatment is still controversial.

Purpose

We aimed to evaluate the usefulness of LUS-guided treatment vs. usual care in reducing the major adverse cardiac event (MACE) rate in patients with HF.

Materials and methods

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) identified through systematic searches of MEDLINE, EMBASE, the Cochrane Database, Google Scholar, and SinoMed. The primary outcome was MACEs (a composite of all-cause mortality, HF-related rehospitalization, and symptomatic HF). The required information size was calculated by trial sequential analysis (TSA).

Results

In total, ten RCTs involving 1,203 patients were included. Overall, after a mean follow-up period of 4.7 months, LUS-guided treatment was associated with a significantly lower risk of MACEs than usual care [relative risk (RR), 0.59; 95% confidence interval (CI), 0.48–0.71]. Moreover, the rate of HF-related rehospitalization (RR, 0.63; 95% CI, 0.40–0.99) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration (standardized mean difference, –2.28; 95% CI, –4.34 to –0.22) were markedly lower in the LUS-guided treatment group. The meta-regression analysis showed a significant correlation between MACEs and the change in B-line count (p < 0.05). The subgroup analysis revealed that the risk of MACEs was markedly lower in patients aged up to 70 years (RR, 0.54; 95% CI, 0.44–0.67), with a lower rate of atrial fibrillation (< 27.2%) (RR, 0.53; 95% CI, 0.43–0.67), and with a lower NT-proBNP concentration (< 3,433 pg/ml) (RR, 0.51; 95% CI, 0.40–0.64). TSA indicated a lower risk of MACEs with LUS-guided treatment than with usual care among patients with HF (p < 0.05).

Conclusion

Lung ultrasound seems to be a safe and effective method to guide HF treatment.

Systematic review registration

[https://inplasy.com/], identifier [INPLASY202220124].

Normalising lung ultrasound

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Lung Ultrasound-Guided Fluid Management versus Standard Care in Surgical ICU Patients: A Randomised Controlled Trial

The value of lung ultrasound (LU) in assessing extravascular lung water (EVLW) was demonstrated by comparing LU with gold-standard methods for EVLW assessment. However, few studies have analysed the value of B-Line score (BLS) in guiding fluid management during critical illness. The purpose of this trial was to evaluate if a BLS-guided fluid management strategy could improve fluid balance and short-term mortality in surgical intensive care unit (ICU) patients. We conducted a randomised, controlled trial within the ICUs of two university hospitals. Critically ill patients were randomised upon ICU admission in a 1:1 ratio to BLS-guided fluid management (active group) or standard care (control group). In the active group, BLS was monitored daily until ICU discharge or day 28 (whichever came first). On the basis of BLS, different targets for daily fluid balance were set with the aim of avoiding or correcting moderate/severe EVLW increase. The primary outcome was 28-day mortality. Over 24 months, 166 ICU patients were enrolled in the trial and included in the final analysis. Trial results showed that daily BLS monitoring did not lead to a different cumulative fluid balance in surgical ICU patients as compared to standard care. Consecutively, no difference in 28-day mortality between groups was found (10.5% vs. 15.6%, p = 0.34). However, at least 400 patients would have been necessary for conclusive results.

Effects of Lung Ultrasonography-Guided Management on Cumulative Fluid Balance and Other Clinical Outcomes: A Systematic Review

Lung ultrasonography is accurate in detecting pulmonary edema and overcomes most limitations of traditional diagnostic modalities. Whether use of lung ultrasonography-guided management has an effect on cumulative fluid balances and other clinical outcomes remains unclear. In this systematic review, we included 12 studies using ultrasonography guided-management with a total of 2290 patients. Four in-patient studies found a reduced cumulative fluid balance (ranging from -0.3 L to -2.4 L), whereas three out-patient studies found reduction in dialysis dry weight (ranging from -2.6 kg to -0.2 kg) compared with conventionally managed patients. None of the studies found adverse effects related to hypoperfusion. The use of lung ultrasonography-guided management was not associated with other clinical outcomes. This systematic review shows that lung ultrasonography-guided management, exclusively or in concert with other diagnostic modalities, is associated with a reduced cumulative fluid balance. Studies thus far have not shown a consistent effect on clinical outcomes.

Dynamic assessment of lung injury by ultrasound in patients with acute paraquat poisoning

Objective

To investigate the value of ultrasound in the dynamic assessment of lung injury after acute paraquat poisoning.

Methods

A prospective observational study was performed on patients with paraquat poisoning from admission to day 28 or discharge. Ultrasound assessment of the lungs was performtyed every 48 hours. The correlation of the lung ultrasound score (LUS) with other indicators was analyzed.

Results

Twenty-six patients were enrolled, with an average age of 46 ± 16 years. The average toxic dose was 95 ± 51 mL. The intensive care unit (ICU) stay averaged 9 ± 8 days, and the 28-day mortality was 88.5%. There was a significant negative correlation between LUS and oxygenation index (rho = −0.896) and a significant positive correlation between LUS and carbon dioxide concentration (rho = 0.567). Lung ultrasound and computed tomography imaging correlated closely.

Conclusion

Lung ultrasound can reflect changes in lung status in patients with paraquat poisoning and can be used to evaluate lung injury in these patients.

Trial registration: ChiCTR, ChiCTR-DDD-16010211. Registered 21 December 2016, http://www.chictr.org.cn/listbycreater.aspx.

Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.

In Vivo Assessment of Lung Ultrasound Features Mimicking Viral Pneumonia Using a Large Animal Model

Lung ultrasound (LUS) is a practical tool for lung diagnosis when computer tomography (CT) is not available. Recent findings suggest that LUS diagnosis is highly advantageous because of its mobility and correlation with radiological findings for viral pneumonia. Simple models for both educational evaluation and technical evaluation are needed. Therefore, this work investigates the usability of a large animal model under aspects of LUS features of viral pneumonia using saline one lung flooding. Six pigs were intubated with a double-lumen tube, and the left lung was instilled with saline. During the instillation of up to 12.5 ml/kg, the sonographic features were assessed. All features present during viral pneumonia were found, such as B-lines, white lung syndrome, pleural thickening, and the formation of pleural consolidations. Sonographic findings correlate well with current LUS scores for COVID19. The scores of 1, 2, and 3 were dominantly present at 1-4-, 4-8-, and 8-12-ml/kg saline instillation, respectively. The noninfective animal model can be used for further investigation of the LUS features and can serve in education, by helping with the appropriate handling of LUS in clinical practice during management of viral pneumonia.

Impact of an ultrasound-driven diagnostic protocol at early intensive-care stay: a randomized-controlled trial

Background

Point-of-care ultrasound (POCUS) is a tool in increasing use, but there is still a lack of basics for its routine use and evidence of its impact in intensive care.

Objective

To measure the impact of POCUS on resource utilization, diagnostic accuracy, and clinical management in medical-surgical intensive care units (ICUs).

Methods

Prospective, controlled study, in two polyvalent ICUs. The patients were randomly assigned to POCUS or control group.

Interventions

POCUS patients received systematic ultrasound examination of optic nerve, lung/pleura, heart, abdomen, and venous system, performed at the bedside by trained intensivists. Control patients were treated by critical care specialists who do not perform ultrasound in their clinical practice.

Results

We included 80 patients, 40 per group. There were no significant differences in age, sex, APACHE II score, or admission diagnosis. POCUS group used fewer resources per patient in the first 5 days of hospitalization: chest radiography (2.6 ± 2.0 vs 4.1 ± 3.5, P = 0.01), additional ultrasound evaluations performed by a radiology specialist (0.6 ± 0.7 vs 1.1 ± 0.7, P = 0.002), and computed tomography studies (0.5 ± 0.6 vs 0.9 ± 0.7, P = 0.007). Time to perform any requested ultrasound evaluation after ICU admission was 2.1 ± 1.6 h versus 7.7 ± 6.7 h (P = 0.001). Systematic ultrasound evaluation led to better characterization of ICU admission diagnosis in 14 (35%) patients and change in clinical management in 24 (60%). POCUS group had lower fluid balance at 48 and 96 h after admission (P = 0.01) and spent less time mechanically ventilated (5.1 ± 5.7 days vs 8.8 ± 9.4, P = 0.03).

Conclusions

Systematic application of POCUS may decrease utilization of conventional diagnostic imaging resources and time of mechanical ventilation, and facilitate meticulous intravenous fluid administration in critically ill patients during the first week of stay in the ICU.

Trial registration ClinicalTrials.gov Identifier: NCT03608202.