Unlocking the Potential: Can Point-of-Care Ultrasound-Guided Resuscitation Impact the Clinical Care for Adults With Shock?*

Point-of-care ultrasound (POCUS) is rapidly evolving into an essential diagnostic tool for the management of critically ill patients. In the hands of well-trained clinicians, POCUS enables the prompt bedside assessment of pathophysiology and hemodynamics, with studies underscoring its diagnostic accuracy for determining the etiology of shock and respiratory failure (1). Additionally, technological advances over the past decade have continually enhanced the portability, user-friendliness, and affordability of ultrasound devices, making them a ubiquitous fixture in inpatient clinical practice. Although the use of POCUS continues to expand across the spectrum of healthcare settings, there is a relative paucity of robust data regarding the benefit of POCUS on patient-centered outcomes, particularly in patients with shock. Thus far, the impact of POCUS-driven clinical outcomes has been primarily studied in non-ICU and emergency department settings, focusing on patients with respiratory insufficiency, heart failure, and cardiac arrest (2–4). Many of these studies demonstrate that POCUS-guided management improves the clinical decision-making process, with patients in the POCUS group having higher odds of receiving appropriate therapy. However, the impact of POCUS-guided care, compared with conventional management, on other outcomes such as hospital length of stay, has yielded mixed results. In this issue of Critical Care Medicine, Basamji et al (5) present a systematic review and meta-analysis exploring the impact of ultrasound-guided resuscitation in critically ill patients with shock. This comprehensive review examined 18 randomized controlled trials with an accumulative patient population of 2227. The authors examined the influence of POCUS on physician management decisions, encompassing the timing and necessity of interventions and diagnostic tests, and patient-important outcomes. Overall, the authors found mixed results. There seems to be a beneficial impact on vasoactive medications, lactate clearance, and renal replacement therapy, but other metrics did not show statistically significant results. However, the study's key finding was the reduction in 28-day mortality associated with POCUS-guided resuscitation. The relative risk was 0.88 (95% CI, 0.78–0.99) based on data from 2163 patients in 17 randomized controlled trials. The finding of a mortality benefit for POCUS-guided resuscitation is likely to excite the POCUS community, particularly those advocating for its incorporation into standard practice for the evaluation of undifferentiated shock. Clearly, POCUS provides a rapid assessment of the pathophysiology underlying cardiopulmonary failure and circulatory shock. For instance, consider a 66-year-old patient with a history of hypertension, atrial fibrillation, and recently diagnosed B-cell lymphoma presenting with hypotension, altered mental status, tachypnea, and tachycardia. Given the history and clinical presentation, the bedside clinician would likely consider a broad differential for shock, including pulmonary embolism, hypovolemia, tamponade, or sepsis. The addition of POCUS to the clinical evaluation allows the clinician to quickly uncover the presence of a circumferential pericardial effusion causing compression of the right-sided cardiac chambers with concomitant dilation of the inferior vena cava. Cardiac tamponade is diagnosed as the cause of obstructive shock, and the appropriate interventions are promptly initiated. Without POCUS, the clinician would rely on less expeditious diagnostic methods, which could delay the initiation of targeted therapies and potentially negatively impact the patient's outcome. Therefore, the capability of POCUS to rapidly identify the etiology of shock may accelerate the restoration of systemic perfusion. This may explain some of the beneficial outcomes observed in the POCUS-guided cohort in the study by Basamji et al (5), such as improved lactate clearance, reduced duration of vasoactive medications, reduced need for renal replacement therapy, and, lower 28-day mortality rates. While encouraging, one should interpret the study findings by Basamji et al (5) with cautious optimism. The majority of the randomized clinical trials analyzed in the systemic review were single-center investigations that may overestimate the treatment effect. Notably, the highest-quality randomized controlled trial, a substantial multicenter prospective study utilizing a comprehensive POCUS protocol, did not reveal any statistically significant benefits in clinical outcomes (6). Furthermore, most of the analyzed studies did not report the examiners' characteristics. In the few studies that did, the physicians who performed the POCUS examinations were expert ultrasound practitioners, and they may not have been the same clinicians caring for the patients. This starkly contrasts with real-world practice, where practitioners with varying levels of imaging expertise use POCUS at the bedside to make clinical decisions. Previous research has shown a poor inter-rater agreement between expert and novice learners regarding ultrasound-guided fluid status assessment, lung ultrasound findings, and certain cardiac parameters (7,8). This emphasizes the necessity for future studies to evaluate outcomes in relation to the operators' training experience to better understand the utility of POCUS in practical clinical environments. For example, one could compare the clinical use of POCUS during the daytime when more experts are likely to be available vs. bedside imaging performed at night. The results of such pragmatic studies would also provide the foundation for refinement and targeted improvements of POCUS educational training models. In addition to its diagnostic applications, POCUS can guide therapeutic interventions through the assessment of volume status and fluid responsiveness that can direct resuscitation in shock. This ultrasound-guided assessment may potentially influence a clinician's prescription of fluid therapy. However, the results of this systemic review fail to demonstrate that POCUS-guided resuscitation results in any meaningful change in the volume of fluid administered. Similarly, there was no difference in outcomes between the cohorts on factors that could be influenced by cumulative fluid balance such as the duration of mechanical ventilation, and the hospital and ICU length of stay (5). These results should not discourage the POCUS community, as the findings may reflect an underuse of POCUS in our daily practice. Much of the current literature on POCUS-driven outcomes is derived from studies where bedside ultrasound examinations were conducted during the preliminary patient evaluation in the emergency department. It is unrealistic to expect that a single POCUS examination at a specific time during a patient's hospital stay could result in meaningful differences in outcomes such as hospital length of stay. The clinical course is typically dynamic, and the initial presentation may evolve as the underlying pathophysiology changes with therapeutic interventions. Additionally, the findings of Basamji et al (5) may reflect the prevalent current practice, where clinicians are more likely to evaluate a deteriorating patient with ultrasound rather than a relatively stable patient who may benefit from ultrasound-guided adjustments in vasopressor or fluid therapy. Indeed, in patients with sepsis, incorporating POCUS during morning rounds on a routine basis, compared with its use on an as-needed basis, is associated with decreased cumulative fluid balance, shortened duration of mechanical ventilation, and ICU length of stay (9). Ultrasound-guided deresuscitation remains another underutilized facet of POCUS. To date, the POCUS literature has focused on early-phase fluid therapy, with little attention to deresuscitation. However, POCUS-guided deresuscitation has the potential to ensure adequate decongestion and influence patient outcomes. Another potential advantage of POCUS utilization is the reduced need for formal diagnostic studies. In this review, the authors report that POCUS-guided management reduces the number of formal diagnostic transthoracic echocardiograms (TTEs) ordered, with an absolute difference of 9%. These results must be considered in the appropriate context. The findings were primarily based on an industry-sponsored study where investigators used a disposable miniature monoplane transesophageal echocardiography probe (10). Thus, the costs associated with the use of disposable TEE probes must be weighed against any savings from reductions in formal TTE examinations. When defining the true value of POCUS, the discourse needs to extend beyond absolute monetary savings from reductions in certain diagnostic studies and must consider its overall value in reducing preventable complications, improved outcomes, speed of diagnosis, and patient satisfaction. While this systematic review addresses some of these factors, the answers to other questions, especially POCUS reducing preventable complications, remain elusive. The heterogeneity of available data regarding examiner characteristics, including training experience, protocols being used, and organ systems being examined, with most studies focusing on cardiac ultrasound, underpin the challenges in effectively exploring the true value of POCUS in critical care settings. Additionally, the growth of POCUS as a fundamental diagnostic imaging modality raises some critical questions about the state of our current POCUS ecosystems. It is essential to recognize that the responsible integration of POCUS into clinical practice requires the development of an institutional bedside ultrasound program that includes processes for image archiving, documentation, quality assurance, education, and privileging standards. Unfortunately, currently, the vast majority of clinical practice environments lack comprehensive POCUS programs that are fully integrated into healthcare delivery systems. In summary, this systematic review and meta-analysis illustrates the potential benefits of POCUS in the treatment of shock. Paramount is the signal for a possible reduction in mortality. However, the authors' findings are tempered by the mixed results in other clinical outcomes and the quality of the existing data. The findings of the study by Basamji et al (5) underscore that unlocking the true potential of POCUS in shock management requires enhanced training methods, practical strategies to incorporate POCUS into daily practice, integration of POCUS programs into institutional healthcare delivery systems, and, most importantly, the appropriate utilization of POCUS throughout the continuum of a patient's care, from initial diagnostics to the deresuscitation phase.