AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 8, NUMBER 1

January 1991

HOW DO PERINATOLOGISTS MANAGE PREECLAMPSIA? Val Catanzarite, M.D., Ph.D., J. Gerald Quirk, M.D., Ph.D., and Gary Aisenbrey, M.D.

The members of the Society of Perinatal Obstetricians were surveyed regarding management of preeclampsia, with focus on drug therapy, use of invasive monitors, and both general policies and treatment of hypothetical cases of preterm severe preeclampsia. There was agreement that magnesium sulfate should be given to all patients with preeclampsia during labor and postpartum and that blood pressure should be held to about 160/105 mmHg. The drugs of choice for control of blood pressure were hydralazine, alpha-methyldopamine, and cardioselective beta-blockers. Most perinatologists use invasive monitors only for specific indications, but a substantial minority use either arterial lines or central venous pressure monitors routinely in severe preeclampsia. There was no consensus with respect to management of preterm, severe preeclampsia, but even among the 49% of respondents who volunteered an unequivocal policy of "deliver regardless of gestational age," over three fourths would hospitalize and observe in selected cases meeting American College of Obstetrics and Gynecology criteria for severe preeclampsia.

Preeclampsia is among the most common pathologic conditions treated by obstetricians and is a major cause of fetal and maternal morbidity and mortality. For many aspects of management, however, variation in published strategies is striking. In order to determine which areas of management are and which are not commonly accepted, the members of the Society of Perinatal Obstetricians (SPO) were surveyed. MATERIALS AND METHODS

The survey was designed to investigate general policies regarding drug therapy, use of invasive monitors, and approach to preterm cases by means of the direct questions shown in Figure 1, and also to explore the relationship between stated policies about preterm, severe preeclampsia and individual case management decisions, by means of hypothetical case presentations. Each patient was described as a healthy nullipara with a baseline blood pressure (BP) of 100/60 mmHg, a single fetus, and a 1 cm dilated, long, soft cervix with the vertex at - 1 station. Details

of cases are given in Table 1. Each case met American College of Obstetrics and Gynecology (ACOG) criteria for severe preeclampsia.x Severity scores of 1 and 10 were assigned to cases 1 and 2, to set a scale, and respondents were asked to assign severity scores to cases 3 through 10 and give management plans and comments for cases 1 through 10. Management plans were scored as 1 if the respondent chose home or hospital observation, 2 for trial of labor induction, and 3 for cesarean section. It was assumed that BPs would remain unchanged at bed rest. If the respondent indicated a contingent plan (that is, "observe but induce labor if BP unchanged"), the ultimate plan was inferred. No score was assigned when the management plan was unclear. The test cases were designed to investigate three specific hypotheses about perception of disease severity. These were that: (1) maternal age does not affect perceived severity, (2) multisystem disease (thrombocytopenia and elevated liver enzymes) is considered as ominous as headache and severe hypertension (BP 180/110 mmHg), and (3) management plans would be determined by perceived disease severity and gestational age.

Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Arkansas Medical Center, Little Rock, Arkansas, and Perinatal Center, Presbyterian Medical Center, Albuquerque, New Mexico Reprint requests: Dr. Catanzarite, Division of Maternal Fetal Medicine, Sharp Memorial Hospital, P.O. Box 232230, San Diego, CA 92193-2230 Copyright © 1991 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.

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ABSTRACT

AMERICAN JOURNAL OF PER1NATOLOGY/VOLUME 8, NUMBER 1

January 1991

YOUR INSTITUTION YEARLY DELIVERY VOLUME: % PREECLAMPTICS:

INVASIVE MONITORS

*INSURED PATIENTS:

For severe preeclanptics, how often and why do you use:

MANAGEMENT PHILOSOPHY MGSO, When do you prescribe MGSO preeclampsia? Never

Always

ARTERIAL LINES? CVP LINES? SWAN-GANZ CATHETERS?

during labor in

At your institution, who places these lines?

Only vhen_

ARTERIAL LINES: CVP LINES: S-G CATH:

Dose and Route? How do you aonitor therapy? (checfc all that apply) Reflexes

Mg Level

PRETERM CASES

Other:

Please briefly describe your approach to the patient with pretera preeclanpsia. What criteria (gestational/severity) do you use in deciding upon delivery?

How long do you continue MGSO. postpaxtim? ANTIHYPERTENSIVES

Do you check L/S ratios? Give steroids for lung maturation? Give antepartun phenobarbitol, etc.,?

At what sustained BP do you give antihypertensives? Antepartum _

OTHER: OTHER: OTHER:

ANESTH "ANESTH "ANESTH

OB "OB "OB

Postpartua

CESARJEAN SECTION LABOR INDUCTION

What is your cesarean section rate for:

Which agents do you use for labor induction? (checX all that apply): PGE2

Oxytocin Figure 1.

Pretera severe preeclampsia (before 32 weeks): Pretera severe preeclaapsia (32-37 weeks): Tera severe preeclaapsia

Other:

Survey form. This section covers demographics and general policy questions.

The survey was sent to all members of SPO; responses received within 60 days of mailing were entered into a Lotus spreadsheet and analyzed using STATSOFT statistical software. For general policy questions, descriptive statistics were used. For comparisons between groups of respondents, the unpaired t test, sign test, and chi-square test were used, and, for comparisons of responses to different cases, the paired t test was used. Step wise regression analysis was used to relate judgments about severity and management to patient data in hypothetical cases; for these, the F test was used to determine statistical significance.

Table 1.

Case Age

Gravida/ Para

PLT

SGOT

2 4

36 45

230 20

15 420

4

38 42

120 170 140 36 224 190 215 120

60 15 24 162 28 26 26 76

30

140/80 180/120

3 4 5

42 23

6

25 34 21 32 17

2/0 1/0 2/0 2/0 3/0 1/0

35 31 26 29 32 39 33 36

170/110 180/110 160/100 1 50/90 170/110 155/105 165/105 160/110

1/0 2/0

Responses HCT

31

9 10

Summary of Hypothetical Cases and Responses Urine Protein

1/0 4/0

7

Seven hundred seventy-eight forms were mailed to SPO members representing 192 institutions: four were undeliverable, three respondents disqualified themselves from answering, six were received beyond 60 days from mailing, and 217 completed forms suitable for analysis were received from 218 individuals representing 142 institutions (all within the United States and Canada). Yearly delivery volumes given by respondents averaged 4472 (range, 350 to 20,000). Estimated rates of preeclampsia ranged from 1 to 19%, with a mean of 8.1%.

BP

25 21

8

RESULTS

EGA

1 2

19

% % %

3 4 3 4 4

3 4

35 41 42 37 42 40

Symptoms None Severe headache & epigastric pain None Headache None None Mild headache None None None

Severity 1 (0.0) 10 (0.0) 7.1 7.4 6.5 8.2 7.2 6.0 6.0 7.5

(1.4) (1.3) (1.5) (1.3) (1.4) (1.6) (1.4) (1.4)

Management 1.0 (0.0) 2.4 (0.4) 1.8 1.8 1.3 1.8 1.8 2.0 1.4 2.0

(0.4) (0.6) (0.5) (0.6) (0.6) (1.3) (0.5) (0.3)

Response values are mean (standard deviation). Severity was scored from 1 to 10, with a score of 1 assigned to case 1 and a score of 10 assigned to case 2 for reference. Management scored 1 for observation, 2 for induction of vaginal delivery, and 3 forcesarean section. EGA = Estimated Cestational Age, HCT = Hematocrit, PLT = Platelet Count x 1000/cu. mm.

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Which medications do you use?

H O W PERINATOLOGISTS MANAGE PREECLAMPSIA/Catanzarite, Quirk, Aisenbrey

for specific indications, such as pulmonary edema or oliguria. Frequent or universal use of arterial lines was no different when obstetricians (as opposed to anesthesiologists, surgeons, or medical specialists) placed these lines, but for Swan-Ganz catheters, rates were 5 of 49 when obstetricians placed these versus 3 of 149 when other services did (p = 0.011, chi square). The next questions focused on the management of preterm cases of preeclampsia. In response to "general policy" queries, 44 respondents indicated that they sometimes use lecithin to sphingomyelin (L/S) ratios in formulating management plans; 55 sometimes use corticosteroids to accelerate lung maturation, and six sometimes use phenobarbitol for antepartum sedation. One hundred seven (49%) respondents stated that they deliver all patients with severe preeclampsia, regardless of gestational age ("deliver all" group), and 58 (27%) stated that they try to delay delivery in at least some cases of preterm, severe preeclampsia ("delay some") group. Estimates of cesarean section for severe preeclamptics less than 32 weeks, 32 to 37 weeks, and more than 37 weeks were 73 ± 21%, 50 ± 19%, and 31 ± 16%, respectively, but there were responses as low as 10% and as high as 100% for each range. Management plans for the hypothetical cases were compared to "general policy" responses. Interestingly, the "deliver all" group perceived greater severity for seven of the eight cases than the "delay some" group (p < 0.01). Mean management scores for the "deliver all" group, as expected, were more aggressive than scores for the delivery some group in all eight cases (p < 0.001). Although all eight test cases met ACOG criteria for severe preeclampsia, 85 (79%) of 107 obstetricians in the "deliver all" group chose hospitalization and observation over expeditious delivery in at least one of the eight test cases (compared with 56 [97%] of the 58 in the "delay some" group and 186 [86%] of

PLACEMENT OF INVASIVE MONITORS

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The first set of questions asked how magnesium sulfate (MgSO4) was used during labor in preeclampsia, by which route it was given, how therapy was monitored, and how long it was continued postpartum. Of 215 responses, 179 prescribe MgSO4 in all cases, 34 use MgSO4 selectively (based on severity or deep tendon reflexes), one reserved MgSO4 for eclampsia, and one respondent never prescribes MgSO4. Two hundred fourteen indicated route of administration; 208 give MgSO4 intravenously (with loading doses 2 to 10 gm and maintenance doses ranging from 1 to 4 gm/hr), three intramuscularly (10 gm IM, then 5 gm IM every 4 hours), and three use a combination of intravenous and intramuscular MgSO4. Two-hundred eleven described their method of monitoring therapy: 21 used primarily magnesium levels, whereas 190 used primarily deep tendon reflexes. Two-hundred ten indicated duration of therapy: 12 continue MgSO4 until diuresis, and 198 continue MgSO4 for 1 to 48 hours, with a mean of 23.5 ± 5.3 hours. We asked which antihypertensive medications were given, and for which levels of sustained hypertension they were prescribed. Hydralazine was named by 198 respondents, alpha-methyldopamine by 97, and cardioselective beta-blockers by 55. Medications given by less than ten respondents included clonidine, prazosin, and sodium nitroprusside. Levels of systolic and diastolic BP for treatment ranged from 140/90 to 200/160 torr with means of 158/105 ± 10/10 torn When vaginal delivery is indicated, all 217 respondents use oxytocin, 85 sometimes use prostaglandin E2 (PGE2), 11 use amniotomy, and nine use laminaria or other mechanical means, for cervical ripening and labor induction. We asked how often and for what indications arterial, central venous pressure, and Swan-Ganz catheters are used, and who places these monitors. Responses to these questions are summarized in Figure 2. Over two thirds of respondents for each type of monitor use them either "never" or only "rarely,"

INVASIVE MONITORING

FREQUENCY OF RESPONSES

FREQUENCY OF RESPONSES

NEVER/RARELY \7/Z\

SWAN-GANZ

[Z7H

ARTERIAL

OCCASIONALLY IV\)

CVP.

FREQUENTLY/ALWAYS ¥77\

SWAN-GANZ

Figure 2. Use of invasive monitors. A: A histogram of responses to the question of who places invasive monitors; B: Frequency of use of arterial and central venous pressure (CVP) lines and Swan-Ganz catheters.

Q

9

217 among all respondents). In case 6, a patient with thrombocytopenia and elevated liver enzymes at 29 weeks, 19 of 107 (18%) in the "deliver all" group 11 of 58 (19%) in the "delay some" group and 44 of 217 (20%) among all respondents) would choose to hospitalize and observe (see Table 1). The mean differences for severity and management scores between otherwise similar cases 3 (age 42 years) and 10 (maternal age 17 years) were —0.35 (p < 0.005, paired t test) and -0.09 (p < 0.005), indicating that perceived disease severity and urgency of intervention are slightly but statistically significantly greater with lower maternal age. Severe hypertension (case 6) was perceived as significantly less ominous than multisystem disease (case 4), with severity difference -1.00 (p < 0.001) and was managed less aggressively (management score difference —0.24, p < 0.001). It was found that the combination of gestational age and assessed severity was significantly predictive of, but did not determine, the management strategy. For the binary choice between observation and delivery by either induction or cesarean section, the regression analysis produced at R2 value of 0.47 (p < 0.001, F test). For determination of overall management decision, the corresponding figure was R2 = 0.38 (p < 0.001, F test). Regression analysis was also performed to determine how well the data in test cases predicted severity and management. Mean arterial pressure (MAP) and platelet count predicted severity score with R2 = 0.66 (p < 0.001, F test), and MAP, gestational age, and platelet count predicted management score with R2 = 0.38 (p < 0.001, F test). Inclusion of other data did not substantially improve the regression fits.

DISCUSSION

The results of this survey indicate general agreement among perinatologists with respect to drug therapy, less uniformity in use of invasive monitors, and considerable divergence of opinion in judgment of disease severity and in the management of preterm, severe preeclampsia. As with all voluntary surveys, the results of this mailing are subject to potential sampling bias. Responses were collated for only 28% of the forms mailed; although over two thirds of institutions and offices of SPO members were represented, we cannot be certain of whether the results presented here would be characteristic of SPO members in general; all findings must be viewed with this limitation in mind. MgSO4 is the standard treatment for seizure prophylaxis during labor in preeclampsia; 83% of respondents use it for all preeclamptics, and only one respondent does not use this medication. Similarly, there was little diversity of opinion about control of hypertension; perinatologists treat BPs of at least 158/105 ± 10/10 torr, and the majority use hydral10 azine, alpha-methyldopamine, or cardioselective beta-blockers. To accomplish vaginal delivery, all use

January 1991

oxytocin for labor induction. Interestingly, 39% also use PGE2 for cervical ripening or labor induction, although it is not approved by the Food and Drug Administration for either indication. Use of invasive monitors is less homogeneous. These monitors are used either never, or for occasional or rare indications by more than two thirds of respondents. About 10% of respondents use arterial or central venous pressure lines either routinely or "often." The use of arterial and central venous lines is no different when obstetricians place them, suggesting that perceived utility, rather than availability, limits use. For Swan-Ganz catheters, respondents from institutions where obstetricians place these lines reported more frequent use; this may represent either research interest or perceived utility. The management of preterm, severe preeclampsia is a subject of considerable controversy. Recent publications suggest that severe preeclampsia should be considered to be an indication for delivery, regardless of gestational age.1-2 Of respondents who expressed an unequivocal policy, 71% agreed that all preterm severe preeclamptics should be delivered, whereas 29% stated that they delay delivery for selected cases. However, in hypothetical case management problems, the majority of respondents even among those with a stated unequivocal policy would delay delivery in some cases. A substantial minority would delay delivery even in thrombocytopenic patients. This finding suggests either that perinatologists differ with published criteria for severe preeclampsia or that the policy of "deliver all severe preeclampsia" is viewed as a general rule, which may be tempered by concerns for the fetus. The results of this survey indicate that reasonably uniform policies are applied to drug therapy by perinatologists. Somewhat less agreement in the use of invasive monitoring may reflect the current state of the literature, and it appears that several groups3"5 are seeking to define their appropriate usage. The divergence of opinion in the management of preterm, severe preeclampsia, in contrast to recent literature, suggests that further work, preferably prospective, will be required to define optimal management policies. REFERENCES

1. ACOG Technical Bulletin 91: Management of preeclampsia. American College of Obstetrics and Gynecology, 1986 2. Sibai BM, Taslilmi M, Abdella, TN, et al: Maternal and perinatal outcome of conservative management of severe preeclampsia in midtrimester. Am J Obstet Gynecol 152: 32, 1985 3. Cotton DB, Gonik B, Dorman K, Harrist, R: Cardiovascular alterations in severe pregnancy-induced hypertension: Relationship of central venous pressure to pulmonary capillary wedge pressure. Am J Obstet Gynecol 151: 762-764, 1985 4. Berkowitz R, Rafferty T: Invasive hemodynamic monitoring in critically ill pregnant patients: Role of Swan-Ganz catheterization. Am J Obstet Gynecol 137:127, 1980 5. Groenendijk R, Trimbos JBMJ, Wallenburg HCS: Hemodynamic measurements in preeclampsia: Preliminary observations. Am J Obstet Gynecol 150:232-236, 1984

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AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 8, NUMBER 1

How do perinatologists manage preeclampsia?

The members of the Society of Perinatal Obstetricians were surveyed regarding management of preeclampsia, with focus on drug therapy, use of invasive ...
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