Table 3.

Indicators of Adequate Circulating Volume and/or Resuscitation

Urine output	0.5 – 1.0 ml/kg/hr
Blood pressure*	Within normal range for age
Heart rate**	Variable
Central venous pressure§	3 – 8 mm Hg
Fractional excretion of Na+ (FeNa)$	<1% (indicates hypovolemia)
BUN/Cr ratio¶	≥ 20 (indicates hypovolemia)
Echocardiogram/Ultrasound	Normal Stroke volume and ejection fraction
Base deficit	<5 (suggests hypoperfusion in the absence of carbon monoxide or cyanide poisoning)

^*Blood pressure can be normal even with hypovolemia because of vasoconstriction produced by catecholamines and antidiuretic hormone (vasopressin)

^**Heart rate can be high despite normovolemia because of catecholamines, anxiety and/or pain, and hypermetabolic state.

^§Central venous pressures can be artificially altered by airway pressures, pleural or pericardial fluid or abdominal distension.

^$ $\text{FeNa}=100\times \frac{\text{Sodium}-\text{urinary}\times \text{creatinine}-\text{plasma}}{\text{Sodium}-\text{plasma}\times \text{creatinine}\text{urinary}}$

^¶Blood urea nitrogen (BUN) to creatinine (Cr) ratio