Reliance on central venous pressure with regard to fluid management in preeclampsia deemed dangerous

Haemodynamic, invasive and echocardiographic monitoring in the hypertensive parturient

AIM

To determine the clinical usefulness of invasive and non-invasive haemodynamic assessment in pre-eclampsia.

METHOD

A systematic review of the literature was undertaken, using a MEDLINE electronic search using a combination of MESH headings and textwords. Over 1500 abstracts were perused; we obtained 156 full papers that were related to the subject matter. Of the full papers, 55 yielded relevant information. Hand-searching the reference lists of the retrieved papers completed the search.

RESULTS

There are no data from randomized controlled clinical trials illustrating the clinical usefulness of pulmonary artery catheters or echocardiographic techniques in hypertensive pregnancy. There are a wealth of data illustrating the haemodynamic profiles of both untreated and treated pre-eclamptic women. Data are also available comparing right heart and left heart filling pressures, demonstrating a relatively poor correlation between the two values. The clinical impact of either measurement is unclear. Data are available illustrating the correlation between echocardiographic techniques and pulmonary artery catheterization.

Lack of agreement between central venous pressure and pulmonary capillary wedge pressure in preeclampsia

OBJECTIVE

To establish if agreement exists between central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) measurements in severe hypertension in pregnancy as analyzed by tests of bias, precision, and 95% limits of agreement.

METHODS

In a prospective study, CVP and PCWP data in 30 patients were collected by means of a pulmonary artery catheter from initiation of therapy until delivery. Patients with a diastolic blood pressure of more than 110 mm Hg were included. Correlation and agreement between CVP and PCWP before and after treatment were evaluated.

RESULTS

The correlation coefficient (r) for CVP-PCWP data in 30 untreated patients was r = 0.64 (p = 0.0002) and for 256 pairs of posttreatment data, it was r = 0.53 (p < 0.0001). Linear regression and correlation for each individual patient in 29 patients with more than 3 measurements showed a significant correlation (p < 0.05) in 19 patients (66%). Correlation was poor (p > 0.05) in 10 patients (34%). The mean difference between PCWP and CVP was 3.5 +/- 2.6 mm Hg (limits of agreement: -1.6 to 8.7) in untreated patients. The mean difference between PCWP and CVP for 256 pairs of data derived posttreatment was 4.9 +/- 3.8 mm Hg (limits of agreement: -2.7 to 12. 5).

CONCLUSION

Invasive measurements of CVP and PCWP were found to agree poorly. Until a reliable noninvasive method is available to measure left ventricular preload, PCWP is the measurement of choice when invasive hemodynamic monitoring is necessary in patients with severe preeclampsia.

Fluid management in pre-eclampsia

We review the evidence base for fluid management in pre-eclampsia. Current understanding of the relevant pathophysiology and the possible impact of styles of fluid management on maternal and fetal outcome are presented. There is little evidence upon which to base the management of fluid balance in pre-eclampsia. Reports are conflicting and no large prospective outcome studies of fluid management have been performed. Volume expansion does not appear to reduce the incidence of fetal distress. Pulmonary oedema and oliguria receive particular attention. There is no evidence of long-term renal damage in pre-eclampsia, but there are strong suggestions that pulmonary oedema is linked to fluid administration. Monitoring is discussed and some principles of management are suggested