Acute Pulmonary Edema in Children: Part 2. A Comparison of the Concentration of Total Proteins in Edema Fluid and Serum,as Measured by Refractometer,with Colloid Oncotic Pressure

This study sought to determine in children with pulmonary edema the correlation between the colloid oncotic pressure (COP) of pulmonary edema fluid (PEF) determined by oncometry and the total protein concentration (TPr) determined by refractometry. Methods: Simultaneous samples of PEF and serum (Ser) were obtained from 32 children with either hydrostatic (cardiogenic) pulmonary edema (HPE) or increased permeability (noncardiogenic) pulmonary edema (PPE). The COP was determined by a Weil oncometer and the TPr by a hand-held refractometer. Results: The results indicated a direct linear relationship, with a correlation factor of 0.92. Conclusion: It is suggested that when an oncometer is not available, the clinician can determine TPr using a refractometer. The PEF-TPr:Ser-TPr can be used to differentiate between HPE and PPE. Measuring TPr by refractometry is a simple, accurate, inexpensive way to obtain valuable information at the bedside.