Plasma Volume as an Index of Total Fluid Loss

Perioperative water and electrolyte balance and water homeostasis regulation in children with acute surgery

“…Our study design precluded us from asserting the precise percentage of extracellular fluid deficit at admission, since we did not have the differences between ill weights and well weights, which is the most reliable clinical method to assess the percentage of fluid loss. 20,21 However, even with this limitation, medical history of poor fluid intake before admission, low FE Na values and increased urine osmolality on admission, positive water balance in addition to a marked dilution of plasma albumin and hemoglobin levels observed over the study period, sodium retention as well as a negative balance for potassium, accompanied by increased circulating levels of aldosterone together with increased plasma-AVP levels on admission all suggest that a state of dehydration was present when participants entered hospital. 22 In parallel to the aforementioned, we observed a significant decrease in blood bicarbonate levels at the end of surgery (Table 2).…”

Validity Analysis on the Findings of Dehydration in 2 to 24-Month-Old Children With Acute Diarrhea

“…5 The gold standard used commonly in determining the severity of dehydration in pediatric patients is the patient's percent weight loss, generally defined as the percent difference between the preillness weight and the acute illness weight, or alternatively, as the percent difference between the acute illness weight and the postrehydration weight. [6][7][8][9][10][11][12] However, this is not a useful method in clinical practice, as the patient's preillness weight is most often not available to health care providers at the time of presentation, when they must make a rapid decision as to whether or not the child is severely dehydrated enough to require intravenous fluids. 7,10,12 Historically, physicians have estimated the degree of dehydration in children based on clinical gestalt.…”

“…Unfortunately, individual symptoms and physical findings are often inadequate in determining the degree of dehydration in the pediatric patient, which is important for clinical decision making 5 . The gold standard used commonly in determining the severity of dehydration in pediatric patients is the patient's percent weight loss, generally defined as the percent difference between the preillness weight and the acute illness weight, or alternatively, as the percent difference between the acute illness weight and the postrehydration weight 6–12 . However, this is not a useful method in clinical practice, as the patient's preillness weight is most often not available to health care providers at the time of presentation, when they must make a rapid decision as to whether or not the child is severely dehydrated enough to require intravenous fluids 7,10,12 .…”

Urine Specific Gravity and Other Urinary Indices

“…42 This intravascular component of the fluid deficit should quickly elicit renal compensatory mechanisms including sodium retention. Ongoing research in renal physiology may help explain why urinary indices have not demonstrated accuracy in predicting dehydration in clinical studies.…”