Accuracy of a new bedside method for estimation of circulating blood volume.
OBJECTIVE
To evaluate the accuracy of a modification of the carbon monoxide method of estimating the circulating blood volume.


METHODS
Prospective, clinical study comparing two methods for estimating the circulating blood volume. Carbon monoxide kinetics were studied by computer simulation.


METHODS
Intensive care unit in a university hospital.


METHODS
Intensive care patients receiving intermittent positive-pressure ventilation and healthy volunteers.


RESULTS
The circulating blood volume was determined from measurements of the carbon monoxide saturation of hemoglobin before and after rebreathing a gas mixture containing 20 to 50 mL of carbon monoxide for a period of 10 to 15 mins. A specially designed Water's "to & fro" system was developed to avoid any leakage during intermittent positive-pressure ventilation. Blood samples were taken before, during, and immediately after rebreathing. The amount of carbon monoxide administrated during each rebreathing maneuver resulted in an average increase in the carbon monoxide saturation of hemoglobin of 3.6%. The washin of carbon monoxide was completed within the first 4 to 6 mins of the rebreathing period in nine healthy subjects and within 10 mins in 12 intensive care patients. The 95% limits of agreement between the carbon monoxide method and the radioactive isotope-labeling method was +/- 540 mL (+/- 2 SD).


CONCLUSIONS
Determination of circulating blood volume can be performed with sufficient accuracy using an amount of carbon monoxide that gives rise to an unharmful increase in the carboxyhemoglobin concentration.
Christensen
P
P
Department of Anaesthesiology and Intensive Care, Odense University Hospital, Denmark.
Waever Rasmussen
J
J
Winther Henneberg
S
S
D000328:Adult; D001811:Blood Volume Determination / Q000379:methods / Q000592:standards*; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin / Q000032:analysis; D002860:Chromium Radioisotopes; D003198:Computer Simulation; D003422:Critical Care / Q000379:methods; D005260:Female; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
D002860:Chromium Radioisotopes; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin