Use of the pulmonary artery catheter in severe preeclampsia: a review

Anesthetic considerations in HELLP syndrome

BACKGROUND

HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) is an obstetric complication with heterogonous presentation and multisystemic involvement. It is characterized by microangiopathic hemolytic anemia, elevated liver enzymes by intravascular breakdown of fibrin in hepatic sinusoids and reduction of platelet circulation by its increased consumption.

METHODS

In terms of these patients' anesthetic management, it is essential to consider some details: (1) effective, safe perioperative management by a multidisciplinary approach, and quick, good communication among clinical specialists to achieve correct patient management; (2) neuroaxial block, particularly spinal anesthesia, is the first choice to do the cesarean if there is only moderate, but not progressive thrombocytopenia; (3) if a general anesthesia is required, it is necessary to control the response to stress produced by intubation, especially in patients with either severe high blood pressure or neurological signs, or to prevent major cerebral complications; (4) invasive techniques, e.g., as tracheostomy, arterial, and deep-vein canalization, should be considered; (5) if contraindication for neuroaxial anesthesia exists, rapid sequence intubation with general anesthesia should be regarded as an emergency in patients with full stomach; (6) increased risk of difficult airways should be taken into account.

RESULTS

Optimal patient management can be chosen after considering the risks and benefits of each anesthetic technique, and based on good knowledge of these patients' pathophysiological conditions.

CONCLUSION

Later, close patient monitoring is recommended for potential development of hemorrhagic complications, disseminated intravascular coagulation (DIC), or eclampsia.

Multicenter study of obstetric admissions to 14 intensive care units in southern England

OBJECTIVES

To identify pregnant and postpartum patients admitted to intensive care units (ICUs), the cause for their admission, and the proportion that might be appropriately managed in a high-dependency environment (HDU) by using an existing database. To estimate the goodness-of-fit for the Simplified Acute Physiology Score II, the Acute Physiology and Chronic Health Evaluation (APACHE) II, and the APACHE III scoring systems in the obstetrical population.

DESIGN

Retrospective analysis of demographic, diagnostic, treatment, and severity of illness data.

SETTING

Fourteen ICUs in Southern England.

PATIENTS

Pregnant or postpartum (<42 days) admissions between January 1, 1994, and December 31, 1996.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified 210 patients, constituting 1.84% (210 of 11,385) of all ICU admissions and 0.17% (210 of 122,850) of all deliveries. Most admissions followed postpartum complications (hypertensive disease of pregnancy [39.5%] and major hemorrhage [33.3%]). Seven women were transferred to specialist ICUs. There was considerable variation between ICUs with respect to the number and type of interventions required by patients. Some 35.7% of patients stayed in ICU for <2 days and received no specific ICU interventions; these patients might have been safely managed in an HDU. There were seven maternal deaths (3.3%); fetal mortality rate was 20%. The area under the receiver operator characteristic curve and the standardized mortality ratio were 0.92 (confidence interval [CI], 0.85-0.99) and 0.43 for the Simplified Acute Physiology Score II, 0.94 (CI, 0.86-1.0) and 0.24 for APACHE II, and 0.98 (CI, 0.96-1.0) and 0.43 for APACHE III, respectively.

CONCLUSIONS

Existing databases can both identify critically ill obstetrical patients and provide important information about them. Obstetrical ICU admissions often require minimal intervention and are associated with low mortality rates. Many might be more appropriately managed in an HDU. The commonly used severity of illness scoring systems are good discriminators of outcome from intensive care admission in this group but may overestimate mortality rates. Severity of illness scoring systems may require modification in obstetrical patients to adjust for the normal physiologic responses to pregnancy.

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.

Management of complicated preeclampsia

The complicated preeclamptic patient represents a challenge for the clinician faced with her antepartum or postpartum care. The most serious sequelae of preeclampsia account for a significant portion of maternal morbidity and mortality. Severe preeclampsia also results in an appreciable portion of perinatal morbidity and mortality. In this review, developing trends in the treatment of severe preeclampsia are discussed. Expectant treatment of the patient remote from term, anesthesia choices, and delivery route are reviewed. Developing trends in the pharmacological approach to complicated preeclampsia are discussed. New concepts in the treatment of cerebrovascular preeclampsia and hepatic rupture are outlined and reviewed.

Benefits, risks and alternatives of pulmonary artery catheterization

Twenty-five years after the introduction of the pulmonary artery catheter in clinical practice, its effectiveness in improving patient outcome is seriously questioned. Experts still recommend to use pulmonary artery catheters in selected critically ill patients, although evidence supporting these recommendations is lacking. The risks and the unclear benefits associated with this procedure should prompt the search for alternative, noninvasive monitoring techniques.

Obstetrical anaesthesia for a parturient with preeclampsia, HELLP syndrome and acute cortical blindness

PURPOSE

To report the management of a multigravida presenting with preeclampsia, HELLP syndrome and acute cortical blindness for Caesarean section.

CLINICAL FEATURES

A 39-yr-old woman, with three past uncomplicated pregnancies presented at 33 wk with acute cortical blindness. Based on clinical and laboratory assessment, a diagnosis of preeclampsia with HELLP syndrome was made. A CT scan of her head demonstrated ischaemic lesions of her basal ganglia, extending superiorly to involve both posterior parietal and occipital regions. Infusions of magnesium sulphate and hydralazine were started and an urgent Caesarean section was performed under subarachnoid anaesthesia after insertion of an arterial line and intravenous hydration. The course of anaesthesia and surgery was uneventful and she delivered a live 1540 g female infant. By the following morning, she had recovered some vision and visual recovery was complete by 72 hr postpartum. She underwent an MRI with angiography on the first postpartum day. Ischaemic lesions were confirmed in the same sites identified on CT scan but all major cerebral vessels were patent and no significant vascular abnormality was noted. Her postoperative course was uneventful and she was discharged home seven days postpartum after being prescribed labetalol for continued hypertension.

CONCLUSION

The anaesthetic management of a parturient with acute cortical blindness and HELLP syndrome is modeled on the underlying preeclamptic condition. Invasive monitoring is not routinely indicated but is specifically indicated in some cases. Provided that it is not contraindicated because of prohibitive risk to the mother, regional anaesthesia has particular advantage in these patients. In particular, the use of spinal anaesthesia, which has been discouraged by some for this patient population, should be re-evaluated.

Hypertension and pregnancy-related hypertension

Pregnant women with hypertension can be divided into two groups: normotensive women who develop the uniquely pregnancy-related syndrome of preeclampsia, which is characterized by hypertension, proteinuria, and edema; and women with chronic hypertension who become pregnant and are at increased risk for developing superimposed preeclampsia. Preeclampsia is a syndrome of generalized endothelial dysfunction initiated by abnormal placentation and consequent placental under-perfusion, release of cytokines and other toxins, and vasoconstriction and platelet activation. Preeclampsia is the major cause of both maternal and fetal morbidity and mortality and may be complicated by eclampsia (seizures) and hepatic and renal failure. The process is completely reversible by delivery of the fetus and placenta, but intrauterine growth retardation and premature delivery pose major threats to the fetus and may require care in tertiary care center. Treatment of preexisting or pregnancy-induced hypertension does not prevent or reverse the process, but is justified to prevent maternal cardiovascular complications, especially during labor and delivery.