Complications of pulmonary artery catheterization of obstetric patients

Validation of maternal cardiac output assessed by transthoracic echocardiography against pulmonary artery catheterization in severely ill pregnant women: prospective comparative study and systematic review

OBJECTIVE

Most severe pregnancy complications are characterized by profound hemodynamic disturbances, thus there is a need for validated hemodynamic monitoring systems for pregnant women. Pulmonary artery catheterization (PAC) using thermodilution is the clinical gold standard for the measurement of cardiac output (CO), however this reference method is rarely performed owing to its invasive nature. Transthoracic echocardiography (TTE) allows non-invasive determination of CO. We aimed to validate TTE against PAC for the determination of CO in severely ill pregnant women.

METHODS

This study consisted of a meta-analysis combining data from a prospective study and a systematic review. The prospective arm was conducted in Pretoria, South Africa, in 2003. Women with severe pregnancy complications requiring invasive monitoring with PAC according to contemporary guidelines were included. TTE was performed within 15 min of PAC and the investigator was blinded to the PAC measurements. Comparative measurements were extracted from similar studies retrieved from a systematic review of the literature and added to a database. Simultaneous CO measurements by TTE and PAC were compared. Agreement between methods was assessed using Bland-Altman statistics and intraclass correlation coefficients (ICC).

RESULTS

Thirty-four comparative measurements were included in the meta-analysis. Mean CO values obtained by PAC and TTE were 7.39 L/min and 7.18 L/min, respectively. The bias was 0.21 L/min with lower and upper limits of agreement of -1.18 L/min and 1.60 L/min, percentage error was 19.1%, and ICC between the two methods was 0.94.

CONCLUSIONS

CO measurements by TTE show excellent agreement with those obtained by PAC in pregnant women. Given its non-invasive nature and availability, TTE could be considered as a reference for the validation of other CO techniques in pregnant women. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

RESUMEN OBJETIVO

Las complicaciones del embarazo más graves se caracterizan por trastornos hemodinámicos serios, debido a los cuales existe la necesidad de sistemas validados de monitorización hemodinámica para mujeres embarazadas. Aunque la cateterización de la arteria pulmonar (CAP) mediante termodilución es el patrón de referencia clínico para la medición del gasto cardíaco (GC), este método se usa con poca frecuencia debido a su naturaleza invasiva. La ecocardiografía transtorácica (ETT) permite la determinación no invasiva del GC. El objetivo de este estudio fue validar la ETT frente al CAP para determinar el GC en mujeres embarazadas gravemente enfermas. MÉTODOS: Este estudio consistió en un metaanálisis que combinó datos de un estudio prospectivo y una revisión sistemática. El estudio prospectivo se llevó a cabo en Pretoria (Sudáfrica) en 2003. Se incluyeron mujeres con complicaciones graves en el embarazo que requerían una monitorización invasiva mediante CAP según las directrices de ese momento. Se realizó una ETT en un plazo de 15 minutos de haber realizado el CAP y el investigador no tuvo acceso a las mediciones del CAP. Las mediciones comparativas se extrajeron de estudios similares obtenidos a partir de una revisión sistemática de la literatura y se añadieron a una base de datos. Se compararon las mediciones simultáneas del GC mediante ETT y CAP. La concordancia entre métodos se evaluó a través del método estadístico de Bland-Altman y de coeficientes de correlación intraclase (CCI).

RESULTADOS

Se incluyeron treinta y cuatro mediciones comparativas en el metaanálisis. Los valores medios del GC obtenidos mediante CAP y ETT fueron de 7,39 l/min y 7.18 l/min, respectivamente. El sesgo fue de 0,21 l/min, siendo los límites inferior y superior de la concordancia de -1,18 l/min y 1.60 l/min; el error porcentual fue del 19,1%, y el CCI entre ambos métodos fue de 0,94.

CONCLUSIONES

Las mediciones del GC en mujeres embarazadas mediante ETT muestran una excelente concordancia con las obtenidas mediante CAP. Dada su naturaleza no invasiva y su disponibilidad, la ETT podría considerarse como referencia para la validación de otras técnicas relacionadas con el GC en mujeres embarazadas. : ,。(pulmonary artery catheterization,PAC)(cardiac output,CO),,。(transthoracic echocardiography,TTE)CO。PACTTECO。 : meta。2003。PAC。PAC 15 minTTE,PAC。,。TTEPACCO。Bland-Altman(intraclass correlation coefficients,ICC)。 : meta34。PACTTECO7.39 L/min7.18 L/min。-1.18 L/min、1.60 L/min0.21 L/min,19.1%,ICC0.94。 : TTECOPACCO。,TTECO。.

Hemodynamic assessment in a pregnant and peripartum patient

PATHOPHYSIOLOGY

Critical care in obstetrics has many similarities in pathophysiology to the care of nonpregnant women. However, changes in the physiology of pregnant woman necessary to maintain homeostasis for both mother and fetus, especially during critical illness, result in complex pathophysiology. Understanding the normal physiologic changes during pregnancy, intrapartum, and postpartum is the key to managing critically ill obstetric patients with underlying medical diseases and pregnancy-related complications.

HEMODYNAMIC MONITORING

When the pathophysiology of critically ill obstetric patients cannot be explained by noninvasive hemodynamic monitoring and the patient fails to respond to conservative medical management, invasive hemodynamic monitoring may be helpful in guiding management. Most important, the proper interpretation of hemodynamic data is predicated on knowledge of normal values during pregnancy and immediately postpartum. Invasive hemodynamic monitoring with pulmonary artery catherization has been used in the obstetric population, particularly in patients with severe preeclampsia associated with pulmonary edema and renal failure.

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.