Pulse contour analysis: should good-looking curves be trusted?

Precision of transpulmonary thermodilution: how many measurements are necessary?

BACKGROUND AND OBJECTIVES

To analyse the precision of transpulmonary thermodilution from the PiCCO technique (Pulsion Medical System, Munich, Germany) in everyday intensive care practice in order to ascertain the minimum number of measurements necessary for scientific precision.

METHODS

An observational study in the medical-surgical ICU of a teaching hospital was performed. Thirty consecutive patients from a mixed intensive care population using the PiCCO haemodynamic monitor were included. Five thermodilution measurements were repeated at 2 min intervals. The variability of the cardiac index and the global end-diastolic volume index was analysed with respect to the five consecutive measurements and the mean of the first two, first three, first four and all five measurements.

RESULTS

There was similar distribution among the different measurements and means. The variability of the cardiac index and global end-diastolic volume index, represented by the standard error of means, the coefficient of errors and the confidence intervals, revealed a similar precision in separate measurements and in the different averaging techniques. The coefficient of errors was less than 5% even when calculating the mean of the first two measurements, meeting the criterion of scientific precision, and including patients with arrhythmia and varying blood pressure.

CONCLUSION

Calculating the mean of two good-quality transpulmonary thermodilution measurements is equivalent to the other averaging techniques (three to five measurements) for the cardiac index and global end-diastolic volume index. Any further repeated measurements may be unnecessary and may contribute to volume overloading.

Monitoring of peri-operative fluid administration by individualized goal-directed therapy

BACKGROUND

In order to avoid peri-operative hypovolaemia or fluid overload, goal-directed therapy with individual maximization of flow-related haemodynamic parameters has been introduced. The objectives of this review are to update research in the area, evaluate the effects on outcome and assess the use of strategies, parameters and monitors for goal-directed therapy.

METHODS

A MEDLINE search (1966 to 2 October 2006) was performed to identify studies in which a goal-directed therapeutic strategy was used to maximize flow-related haemodynamic parameters in surgical patients, as well as studies referenced from these papers. Furthermore, methods applied in these studies and other monitors with a potential for goal-directed therapy are described.

RESULTS

Nine studies were identified pertaining to fluid optimization during the intra- and post-operative period with goal-directed therapy. Seven studies (n = 725) found a reduced hospital stay. Post-operative nausea and vomiting (PONV) and ileus were reduced in three studies and complications were reduced in four studies. Of the monitors that may be applied for goal-directed therapy, only oesophageal Doppler has been tested adequately; however, several other options exist.

CONCLUSION

Goal-directed therapy with the maximization of flow-related haemodynamic variables reduces hospital stay, PONV and complications, and facilitates faster gastrointestinal functional recovery. So far, oesophageal Doppler is recommended, but other monitors are available and call for evaluation.