Update on Anesthesia for Severely Preeclamptic Women: The Use of Spinal Anesthesia

Alan C. Santos, MD, MPH Texas Tech Health Sciences Center

Lubbock, TX

Severe Preeclampsia

Hypertension 160/110 mmHg

Proteinuria > 5 g in 24 hours

Coagulation Disorders

Hemodynamics

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50

100

150

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250

MABP PCWP SVR

NormalPreclamptic

Am J Obstet Gynecol 1984; 150:232

mmHg dynes . sec-3

Epidural Anesthesia

Continuous catheter technique

Incremental:

Dose Level Hydration Vasopressor

Effects on uteroplacental perfusion

Hemodynamics With Epidural

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100110120130140150160170180

-60 -30 -20 -10 2 6 10 14 18 22 26 30 34 38 42 44 48 52 56 60Time (min)

MA

BP m

m H

g

MAPPAPPWP

Time gap

Can Anaesth Soc J 1980; 27:389

Lumbar Epidural Analgesia Improves Placental Blood Flow in

Preeclamptics

SUBJECTS: Severely preeclamptic women

ANESTHESIA: Prehydration (LR 500 ml) Epidural analgesia

MEASURED: Placental Blood Flow Blood Pressure

Obstet Gynecol 1982; 59:158

Placental Blood Flow

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4ml 0.5% Bupivacaine 10ml 0.25%Bupivacaine

%

%

Spinal Anesthesia in Preeclamptics: The Argument Against

Uncontrollable spread

Rapid onset of sympathectomy

Greater risk of catastrophic hypotension?

Spinal Anesthesia in Preeclamptics: However!

Improved prenatal care

Desperate times, desperate measures!

Dont we use 2-chloroprocaine for CLEA?

Hypotension Due to SAB in Normotensive and Preeclamptic

Women Having Cesarean Delivery

SUBJECTS: Women having cesarean delivery Normotensive (n=30) Severe Preeclampsia (n=30)

METHODS: Prospective cohort

Anesth Analg 2003; 97:867

MABP During Spinal Anesthesia

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Time (min)

Mea

n B

P (m

mH

g)

PreeclampticsHealthy

Why?

Salutory neuroendocrine/vasopressor effects?

Better prepared, not fasted, had IVs?

Smaller babies, less supine hypotension?

Anesth Analg 2003; 97:621

Confounding Variables

Healthy Preeclampsia

Nulliparous (%) 40% 70%

Neonatal Weight (g) 3067456 1496616

Hypotension: Severe Preeclampsia or Preterm Delivery

Subjects: Women having cesarean delivery Severe preeclampsia Prematurity

Anesthesia: Spinal anesthesia

Methods: Prospective cohort

Anesth Analg 2005; 101:869-75

Results

Preeclampsia Preterm

Hypotension (%) 25 41

Gestational Age (wk) 32.42.4 31.91.9

Fetal Weight (g) 1563523 1690242

Placenta (g) 21384 23278

GA vs RA for Cesarean Delivery in Preeclamptic Women

SUBJECTS: 80 severely preeclamptic women

METHODS: Randomized: General

Epidural Combined spinal-epidural

Obstet Gynecol 1985; 86:193

Preoperative Blood Pressure

Systolic 169 3 178 4 165 3

Diastolic 111 2 113 3 110 2

General Epidural CSE

Intraoperative Blood Pressure

Systolic 112 3 110 3 110 2

Diastolic 60 2 59 3 61 2

Ephedrine (%) 0 30 22

General Epidural CSE

Fluids (ml) and Urine (ml/kg/h)

Preload 401 81 1024 59 987 55

Total fluids 1537 101 2387 110 2255 102

Urine 1.3 0.2 1.9 0.5 1.4 0.3

General Epidural CSE

Fetal

Gestation (wk) 34 1 34 1 36 1

Weight (g) 2138 180 2158 132 2589 159

UA pH 7.30 0.01 7.26 0.01 7.27 0.02

% Apgar < 7 19 10 19

General Epidural CSE

Spinal vs Epidural for Cesarean Delivery With Preeclampsia

Subjects: Women with severe preeclampsia Labor and Scheduled Stabilization: MgSO4 Hydralazine

Anesthesia: Random sequence, not blinded Spinal or epidural Multi-center

Anesth Analg 2005; 101:862-8

Results

Epidural Spinal MABP (mmHg) 7216 6316 Fetal weight (g) 2401762 2410825 Apgar score 7 1 min 5 min

26 % 7 %

15 % 2%

UA pH 7.26 (6.92-7.38) 7.27 (7.13-7.37) Base Excess 4 (0-11) 4(1-12)

Spinal Anesthesia in Preeclamptics: Lets Not Throw the Baby Out With the Bathwater!

Center Mean Difference

1 -12

2 -23

3 -28

4 -8

5 -2

Anesth Analg 2005; 101:859-61

Spinal Anesthesia in Preeclamptics: Lets Not Throw the Baby Out with the Bathwater!

Small difference in MABP, less than 1 min

Of similar magnitude to sleep-wake cycles

No detectable adverse neonatal effects Apgar score UA pH Base Excess

Sympatholysis and UBF Anesth Analg 2005; 101:859-61

Anesthesia in Preeclamptics With Fetal Compromise

SUBJECTS: Preeclamptics DP > 90 mmHg Non reassuring fetal status by FHR

METHODS: RCT Prehydration < 750 ml LR GA or SAB

Anesthesiology 2003; 99:561-9.

Results

General Spinal

Apgar Score 7.6 8

UA pH 7.23 7.20

UA pCO2 50 49

UA pO2 23 21

Base Excess 4.73.3 7.14.0

However!

General Spinal

Prehydration (ml) 393114 454110

Ephedrine (mg) 39 1417

Neonatal Outcome With Spinal vs General Anesthesia

Subjects: Severely pre-eclamptic women having a cesarean delivery

Methods: 82 women randomized to; Spinal - phenylephrine General

J Indian Med Assn 2011; 109:166

Results

Acid-Base Status General Spinal

Mean pH 7.20 7.20

Mean base deficit 8.14 8.14

When to use SAB

Properly prepared mothers BP Control Some hydration

Non-reassuring fetal status? Acute placental abruption?

Hemodynamics

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MABP PCWP SVR

BaselineHydrationHydralazine

Am J Obstet Gynecol 1984; 150:232

mmHg dynes . sec-3

Effects of Hydration in Preeclamptics

SUBJECTS: Women having a CS Normotensive = 7 Preeclamptic = 6

METHODS: Preload lactated Ringers, 1L SAB ANP before/after

Acta Anaesthesiol Scand 1996; 40:1203

ANP Levels (pg/ml)

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25

Normal Preeclamptic

BeforeAfter

Thrombocytopenia and Preeclampsia

SUBJECTS: Pregnant Women 52 normotensive 140 mild preeclampsia 114 severe preeclampsia

RESULTS: PLATELETS < 100K Normotensive 2% Mild Preeclampsia 3% Severe Preeclampsia 30%

Sharma SK et al. Anesthesiology 1999; 90:385

Spinal or Epidural?

INCIDENCE OF SPINAL HEMATOMA Spinal 1:220,000

Epidural 1:150,000

Anesth Analg 1994; 79:1165

Successful Use of SAB

Multisystem disease hemodynamics coagulation

Type of procedure

Urgency

Maternal and fetal condition