Intraoperative Focused Cardiac Ultrasound for Assessment of Hypotension: A Systematic Review

Abstract

Focused cardiac ultrasound (FoCUS) has become a valuable tool to assess unexplained hypotension in critically ill patients. Due to increasing availability of transthoracic echocardiography (TTE) equipment in the operating room, there is a widespread interest in its usefulness for intraoperative diagnosis of hypotension as an alternative to transesophageal echocardiography (TEE). The objective of this systematic review is to evaluate the utility of intraoperative FoCUS to assess patients experiencing unexplained hypotension while undergoing noncardiac surgery. We performed a systematic literature search of multiple publication databases for studies that evaluated the utility of intraoperative FoCUS for assessment and management of unexplained hypotension in patients undergoing noncardiac surgery, including retro- and prospective clinical studies. A summary of the study findings, study quality, and assessment of level of evidence is presented. We identified 2227 unique articles from the literature search, of which 27 were potentially relevant, and 9 were included in this review. The number of patients pooled from these studies was 255, of whom 228 had intraoperative diagnoses with the aid of intraoperative FoCUS. The level of evidence of all studies included was very low according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines. This systematic review has demonstrated that FoCUS may be a useful, noninvasive method to differentiate causes of intraoperative hypotension and guide correcting interventions, although the quality of evidence is very low. Further prospective high-quality studies are needed to investigate whether intraoperative FoCUS has a diagnostic utility that is associated with improved outcomes.

Perioperative applications of focused cardiac ultrasound

“…Physicians without echocardiography expertise may not be able to achieve diagnoses in all of these categories, yet with FOCUS, may be able to rapidly rule in or out common life-threatening conditions and narrow the differential diagnosis. Studies that have reviewed the use of FOCUS for intraoperative hypotension have pointed to hypovolemia and left and RV failure as the most commonly identified causes of hemodynamic disturbances 21,33,36…”

“…Studies that have reviewed the use of FOCUS for intraoperative hypotension have pointed to hypovolemia and left and RV failure as the most commonly identified causes of hemodynamic disturbances. 21,33,36 To effectively incorporate FOCUS into practice, a defined protocol should be followed to lower the cognitive burden of executing the examination, for standardization of care and to provide the opportunity to maximize quality assurance. International guidelines on FOCUS recommend employment of a protocolized examination for FOCUS, 8 though they do not describe such an approach.…”

Focused Cardiac Ultrasound in the Operating Room—Another Important Tool for the Assessment of the Unstable Patient

“…12 This required knowledge of the graduating anesthesia resident fits firmly into the summary that Navas-Blanco et al reach, namely, that intraoperative FoCUS examination is both feasible to perform and useful in identifying the underlying cause of unexplained hypotension. 1 Perhaps the more pressing question is not whether we should do echo, FoCUS, TTE, TEE, or PoCUS, but how we bridge the gap between our current situation and the future? While improving, there remains a small percentage of anesthesiologists that are comfortable with transthoracic imaging, yet within a couple of years, our specialty is expected to be graduating residents with a basic understanding of image acquisition and interpretation.…”

“…While the systematic review pointed toward the feasibility and utility of intraoperative FoCUS, all of the included studies were deemed low quality due to their observational nature and lack of control groups. 1 The lack of randomized clinical trials (RCTs) is noteworthy and reflects the difficulty of designing a randomized trial for hypotensive patients under general anesthesia. The authors conclude that FoCUS may be useful intraoperatively and recommend that additional high-quality prospective studies are needed to assess its utility and impact on outcomes.…”

Design of a workshop for focused rescue transesophageal echocardiography in nurse anesthesia: a small-scale mixed methods study

“…To address this condition, the American Association of Nurse Anesthesiology (AANA) has recommended monitoring and interpretation of TEE as a special privilege for CRNAs [13]. Additionally, the Council on Accreditation of Nurse Anesthesia Educational Programs has identi ed point of care ultrasound-a term that includes "focused" rescue TEE (involving a goal-directed, qualitative assessment technique with a limited number of views chosen to assess for a select number of pathologies; consistent with existing modi ed TEE protocols [4,14]) -as a desired skill in nurse anesthesia training [15].…”