title: Assessment of the agreement between cardiac output measured by bolus thermodilution and continuous methods, with particular reference to the effect of heart rhythm.
abstract: Cardiac output (CO) is a fundamentally important haemodynamic parameter and its continuous measurement has the potential to enable early recognition of haemodynamic trends and earlier therapeutic response. A method of continuous cardiac output (CCO) monitoring is now available for clinical use. The accuracy and reliability of this method has been confirmed in clinical trials but not, to our knowledge, in the presence of abnormal heart rhythms. A comparison was made between CCO and bolus thermodilution methods, to determine if there is a greater difference between their respective determinations of CO when heart rhythm is abnormal. A convenience sample of 38 intensive care patients was used to obtain 410 comparisons of CCO and bolus CO determinations. Heart rhythm associated with each comparison was determined. The comparison produced a measurement bias of -0.07 l/min and limits of agreement of -1.77 to 1.63 l/min. The bias of the two measurements was -0.35 l/min for sinus rhythm, -0.19 l/min for sinus tachycardia and -0.12 l/min for atrial flutter/fibrillation. Increased temperature and heart rate did not affect measurement agreement. In conclusion, the agreement between the bolus and continuous methods is clinically acceptable and is unaffected by the heart rhythms of sinus rhythm, sinus tachycardia and atrial flutter/fibrillation.
authors.affiliation: Intensive Care Unit, Prince Henry Hospital, New South Wales.
authors.forename: M
authors.initials: M
authors.lastname: Boyle
authors.forename: S
authors.initials: S
authors.lastname: Jacobs
authors.forename: T A
authors.initials: TA
authors.lastname: Torda
authors.forename: Y
authors.initials: Y
authors.lastname: Shehabi
mesh_terms: D001145:Arrhythmias, Cardiac / Q000451:nursing* / Q000503:physiopathology; D015982:Bias; D002302:Cardiac Output; D015400:Clinical Nursing Research; D003422:Critical Care; D006801:Humans; D008991:Monitoring, Physiologic / Q000592:standards; D009730:Nursing Assessment / Q000592:standards*; D015203:Reproducibility of Results; D013815:Thermodilution / Q000592:standards*