Extravascular lung water measurement by double indicator dilution in shock and respiratory failure

Clinical quantitation of water accumulation in the lungs is imprecise. The technique of measuring extravascular lung water (EVLW) with double indicator dilution utilizing cold indocyanine green dye has become practical with the addition of a microprocessor. The technique, insertion of a special thermistor tipped arterial catheter and potential problems are described. Our studies with resuscitation of 27 patients in shock indicate little increase in EVLW at 24 hours. On the other hand 19 patients with Adult Respiratory Distress Syndrome (ARDS) had marked increases in EVLW from normal of 5-8 ml/kg to 10.7 to 14.4 ml/kg. No further increases in EVLW were observed in eight ARDS patients requiring fluid resuscitation for associated hypovolemia and hypoperfusion. We feel that measurement of EVLW in critically ill patients offers an opportunity to study the pathophysiology of pulmonary failure.