Resuscitation of critically ill patients in shock from cardiogenic, hypovolemic, obstructive, distributive, or neurogenic etiology is a cornerstone of the care delivered by emergency physicians (EPs).1 Regardless of the etiology, it is essential that the treating EP initiate resuscitative measures in a timely manner and closely trend the patient’s response to these interventions.
The early goal-directed therapy (EGDT) initially proposed by Rivers et al2 in 2001 demonstrated a bundled approach to fluid resuscitation by targeting end points for volume resuscitation, mean arterial blood pressure (MAP), oxygen (O2) delivery/extraction (mixed venous O2 saturation, [SvO2]), hemoglobin (Hgb) concentration, and cardiac contractility. Since then, advancements in laboratory testing and hemodynamic monitoring (HDM) devices further aid and guide resuscitative efforts, and are applicable to any etiology of shock.
In addition to these advancements, the growing evidence of the potential harm from improper fluid resuscitation, such as the administration of excessive intravascular fluid (IVF),3 underscores the importance of a precise, targeted, and individualized approach to care. This article reviews the background, benefits, and limitations of some of the common and readily available tools in the ED that the EP can employ to guide fluid resuscitation in critically ill patients.
The rapid recognition and treatment of septic shock in the ED is associated with lower rates of in-hospital morbidity and mortality.4 The physical examination by the EP begins immediately upon examining the patient. The acquisition of vital signs and recognition of physical examination findings suggestive of intravascular volume depletion allows the EP to initiate treatment immediately.
In this discussion, hypotension is defined as systolic blood pressure (SBP) of less than 95 mm Hg, MAP of less than 65 mm Hg, or a decrease in SBP of more than 40 mm Hg from baseline measurements. Subsequently, shock is defined as hypotension with evidence of tissue hypoperfusion-induced dysfunction.5,6 Although the use of findings from the physical examination to guide resuscitation allows for rapid patient assessment and treatment, the predictive value of the physical examination to assess hemodynamic status is limited.
Visual inspection of the patient’s skin and mucous membranes can serve as an indicator of volume status. The patient’s tongue should appear moist with engorged sublingual veins; a dry tongue and diminished veins may suggest the need for volume resuscitation. On examination of the skin, delayed capillary refill of the digits and cool, clammy extremities suggest the shunting of blood by systemic circulation from the skin to central circulation. Patients who progress to more severe peripheral vasoconstriction develop skin mottling, referred to as livedo reticularis (Figure 1).
The major benefit of the physical examination as a tool to evaluate hemodynamic status is its ease and rapid acquisition. The patient’s vital signs and physical examination can be obtained in the matter of moments upon presentation, without the need to wait on results of laboratory evaluation or additional equipment. Additionally, serial examinations by the same physician can be helpful to monitor a patient’s response to resuscitative efforts. The negative predictive value (NPV) of the physical examination in evaluating for hypovolemia may be helpful, but only when it is taken in the appropriate clinical context and is used in conjunction with other diagnostic tools. The physical examination can exclude hypovolemic volume status with an NPV of approximately 70%.7