Overestimation of low cardiac output measured by thermodilution.
We have investigated the influence of a cold water bolus (CWB) injection on overestimation of cardiac output (CO) in low CO states in anaesthetized dogs. CO was measured using three methods: (1) thermodilution (TD), (2) electromagnetic (EM) flow meter placed on the pulmonary artery and (3) transoesophageal echo-Doppler (OD) placed on the descending aorta. Measurements of CO were obtained before (steady state) and after induction of a low CO state with thiopentone 5 mg kg-1 i.v. After CWB injection, mean CO measured by EM and OD increased by 26% and 27%, respectively (P < 0.05) during steady state, and by 85% and 75% (P < 0.05) during the low CO state. This transient increase was produced by an increase in stroke volume, while heart rate did not change. Frank Starling's law may explain this variation by a sudden increase in preload produced by CWB injection. These results indicate that thermodilution overestimated CO during low CO states when CWB injection was used.
Tournadre
J P
JP
Critical Care Division, Hôpital de l'Hôtel-Dieu, Lyon, France.
Chassard
D
D
Muchada
R
R
D000818:Animals; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging; D002303:Cardiac Output, Low / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003080:Cold Temperature; D004285:Dogs; D015150:Echocardiography, Doppler; D017548:Echocardiography, Transesophageal; D055590:Electromagnetic Phenomena; D018056:Hemorheology / Q000295:instrumentation; D011651:Pulmonary Artery / Q000503:physiopathology; D013815:Thermodilution