Authors’ Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article. The opinions expressed in this paper do not reflect those of the Veteran’s Healthcare administration.
Dr Brant is a critical care fellow, department of critical care, multidisciplinary critical care training program, University of Pittsburgh Medical Center, Pennsylvania. Dr Niehaus is a critical care fellow, department of critical care, multidisciplinary critical care training program, University of Pittsburgh Medical Center, Pennsylvania. Dr Kobzik is a critical care fellow, department of critical care, multidisciplinary critical care training program, University of Pittsburgh Medical Center, Pennsylvania. Dr Goodmanson is a critical care fellow, department of critical care, multidisciplinary critical care training program, University of Pittsburgh Medical Center, Pennsylvania. Dr Skolnik is a critical care fellow, department of critical care, multidisciplinary critical care training program, University of Pittsburgh Medical Center, Pennsylvania. Dr Hamade is a critical care fellow, department of critical care, multidisciplinary critical care training program, University of Pittsburgh Medical Center, Pennsylvania. Dr Schott is an assistant professor, department of critical care medicine and emergency medicine, University of Pittsburgh and University of Pittsburgh Medical Center, Pennsylvania, and director of critical care ultrasonography, VA Pittsburgh Health Care Systems, Pennsylvania.
Some of the most significant advantages to the use of POCUS to guide resuscitation is that it is quick, non-invasive, does not use ionizing radiation, and can be easily repeated. As noted above, it is a requirement for EM residencies to teach its use, so that contemporary graduates are entering the specialty competent in applying it to the care of their patients. Furthermore, POCUS is done at the bedside, limiting the need to potentially transport unstable patients.
Figure 3.
In the most basic applications, POCUS provides direct visualization of a patient’s cardiac function, presence or absence of lung sliding to suggest a pneumothorax, presence of pulmonary edema, assessment of CVP pressures or potential for fluid responsiveness, as well as identification of potential thoracic, peritoneal, or pelvic cavity fluid accumulation that may suggest hemorrhage. There is literature to support that these assessments performed by the EP have been shown to be comparable to those of cardiologists.59,60 With continued practice and additional training, it is possible for EPs to even perform more “advanced” hemodynamic assessments to both diagnose and guide therapy to patients in shock (Figures 3 and 4).61
Figure 4.
Limitations
Although POCUS has been shown as a remarkable tool to help assist the EP in making rapid decisions regarding resuscitation, it is always important to remember its limitations. Most of the studies regarding its use are of very small sample sizes, and further prospective studies have to be performed in order for this modality to be fully relied on.62Compared to some of the previously mentioned HDM devices that may provide continuous data, POCUS needs to be performed by the treating physician, thereby occurring intermittently. Emergency physicians need to be aware of their own experience and limitations with this modality, as errors in misdiagnosis can lead to unnecessary procedures, with resulting significant morbidity and mortality. Blanco and Volpicelli63 describe several common errors that include misdiagnosing the stomach as a peritoneal effusion, assuming adequate volume resuscitation when the IVC is seen to be plethoric in the setting of cardiac tamponade, or mistaking IVC movement as indicative of collapsibility, amongst other described misinterpretations. Several other studies have shown that, despite adequate performance of EPs in POCUS, diagnostic sensitivities remained higher when performed by radiologists.64-67 Thus it remains important for the EPs to be vigilant and not anchor on a diagnosis when in doubt, and to consult early with radiology, particularly if there is any question, to avoid potential adverse patient outcomes.
Summary
There are several ways to diagnose and track resuscitation in the ED, which include physical examination, assessment of serum laboratory values, monitoring of hemodynamic status, and use of POCUS. Unfortunately, none of these methods provides a perfect assessment, and no method has been proven superior and effective over the others. Therefore, it is important for EPs treating patients in shock to be aware of the strengths and limitations of each assessment method (Table).
Table.
The EP will likely need to employ multiple approaches when evaluating a patient in shock—both to confirm a diagnosis as well as perform serial evaluation to trend the response to therapeutic interventions with the goal to restore appropriate perfusion to end-organ tissues. The evaluation tools outlined in this article provide EPs with a wealth of resources to provide care to the most critically ill patients.
Figure 4.