Pregnancy Induced HypertensionPregnancy Induced Hypertension

Jack Lin, M.D.Jack Lin, M.D.Albert Woo, M.D.Albert Woo, M.D.

Advisor: Marissa Lazor, M.D.Advisor: Marissa Lazor, M.D.

Boston University Medical CenterBoston University Medical CenterDept. of AnesthesiologyDept. of Anesthesiology

HypertensionHypertension

• Most common medical problem encountered Most common medical problem encountered during pregnancyduring pregnancy

• 8% of pregnancies8% of pregnancies

• 4 categories:4 categories: Chronic HypertensionChronic Hypertension Pregnancy Induced hypertensionPregnancy Induced hypertension Preeclampsia-eclampsiaPreeclampsia-eclampsia Preeclampsia superimposed on chronic HTNPreeclampsia superimposed on chronic HTN

*Hypertensive disorder in pregnancy may cause an increase in *Hypertensive disorder in pregnancy may cause an increase in maternal and fetal morbidity and remains a leading source of maternal and fetal morbidity and remains a leading source of maternal mortality*maternal mortality*

HypertensionHypertension

• ThirdThird leading cause of maternal mortality, after leading cause of maternal mortality, after thromboembolism and non-obstetric injuriesthromboembolism and non-obstetric injuries

• Maternal DBP > 110 is associated with ↑ risk of placental Maternal DBP > 110 is associated with ↑ risk of placental abruption and fetal growth restrictionabruption and fetal growth restriction

• Superimposed preeclampsia cause most of the morbiditySuperimposed preeclampsia cause most of the morbidity

Pregnancy Induced HypertensionPregnancy Induced Hypertension

• HTN HTN • Usually mild and later in pregnancyUsually mild and later in pregnancy• No renal or other systemic involvement No renal or other systemic involvement • Resolves 12 wks postpartumResolves 12 wks postpartum

• May become preeclampsiaMay become preeclampsia

PreeclampsiaPreeclampsia

• New onset HTN New onset HTN • After 20 weeks of gestation, or After 20 weeks of gestation, or • Early post-partum, previously normotensiveEarly post-partum, previously normotensive• Resolves within 48 hrs postpartumResolves within 48 hrs postpartum

• With the following (Renal or other systemic)With the following (Renal or other systemic)• Proteinuria > 300 mg/24hrProteinuria > 300 mg/24hr• Oliguria or Serum-plasma creatinine ratio > 0.09 mmol/LOliguria or Serum-plasma creatinine ratio > 0.09 mmol/L• Headaches with hyperreflexia, eclampsia, clonus or visual disturbancesHeadaches with hyperreflexia, eclampsia, clonus or visual disturbances• ↑ ↑ LFTs, glutathione-S-Transferase alpha 1-1, alanine aminotransferase or right LFTs, glutathione-S-Transferase alpha 1-1, alanine aminotransferase or right

abdominal painabdominal pain• Thrombocytopenia, ↑ LDH, hemolysis, DICThrombocytopenia, ↑ LDH, hemolysis, DIC

• 10% in primigravid10% in primigravid• 20-25% with history of chronic HTN20-25% with history of chronic HTN

Maternal Risk FactorsMaternal Risk Factors

• First pregnancyFirst pregnancy• Age younger than 18 or older than 35Age younger than 18 or older than 35• Prior h/o preeclampsiaPrior h/o preeclampsia• Black raceBlack race• Medical risk factors for preeclampsia - chronic HTN, Medical risk factors for preeclampsia - chronic HTN,

renal disease, diabetes, anti-phospholipid syndromerenal disease, diabetes, anti-phospholipid syndrome• TwinsTwins• Family historyFamily history

Mild vs. Severe PreeclampsiaMild vs. Severe Preeclampsia

MildMild SevereSevere

Systolic arterial pressure Systolic arterial pressure 140 mm Hg – 160 mm Hg140 mm Hg – 160 mm Hg ≥≥160 mm Hg 160 mm Hg

Diastolic arterial pressure Diastolic arterial pressure 90 mm Hg – 110 mm Hg 90 mm Hg – 110 mm Hg ≥≥110 mm Hg 110 mm Hg

Urinary protein Urinary protein <5 g/24 hr<5 g/24 hrDipstick +or 2 + Dipstick +or 2 +

≥≥5 g/24 hr5 g/24 hrDipstick 3+or 4+ Dipstick 3+or 4+

Urine output Urine output >500 mL/24 hr >500 mL/24 hr ≤≤500 mL/24 hr 500 mL/24 hr

Headache Headache No No Yes Yes

Visual disturbances Visual disturbances No No Yes Yes

Epigastric pain Epigastric pain No No Yes Yes

EtiologyEtiology

Exact mechanism not knownExact mechanism not known

• ImmunologicImmunologic• GeneticGenetic• Placental ischemiaPlacental ischemia

• Endothelial cell dysfunctionEndothelial cell dysfunction• VasospasmVasospasm• Hyper-responsive response to vasoactive hormones (e.g. Hyper-responsive response to vasoactive hormones (e.g.

angiotensin II & epinephrine)angiotensin II & epinephrine)

Symptoms of preeclampsiaSymptoms of preeclampsia

• Visual disturbancesVisual disturbances• HeadacheHeadache• Epigastric painEpigastric pain• Rapidly increasing or nondependent edema - may be a Rapidly increasing or nondependent edema - may be a

signal of developing preeclampsiasignal of developing preeclampsia• Rapid weight gain - result of edema due to capillary leak Rapid weight gain - result of edema due to capillary leak

as well as renal Na and fluid retentionas well as renal Na and fluid retention

PathophysiologyPathophysiology

PathophysiologyPathophysiology

• Airway edemaAirway edema• CardiacCardiac• RenalRenal• Hepatic Hepatic • UterineUterine

Upper airway edemaUpper airway edema

• Upper airway edemaUpper airway edema• Laryngeal edemaLaryngeal edema• Airway obstructionAirway obstruction

• Potential for Potential for airway compromiseairway compromise or or difficulty in intubationdifficulty in intubation

Cardiac/PulmonaryCardiac/Pulmonary

• Increased CO & SVRIncreased CO & SVR• CVP normal or slightly increasedCVP normal or slightly increased• Plasma volume reducedPlasma volume reduced

• Pulmonary edemaPulmonary edema • Decrease oncotic/collid pressureDecrease oncotic/collid pressure• Capillary/endothelial damage Capillary/endothelial damage leak leak• VasoconstrictionVasoconstriction increase PWP and CVPincrease PWP and CVP• Occurs 3 % of preeclamptic patientsOccurs 3 % of preeclamptic patients

HepaticHepatic

• Usually mildUsually mild• Severe PIH or preeclampsia complicated by HELLPSevere PIH or preeclampsia complicated by HELLP

periportal hemorrhagesperiportal hemorrhages

ischemic lesionischemic lesion

generalized swellinggeneralized swelling

hepatic swelling hepatic swelling epigastric pain epigastric pain

RenalRenal

• Adversely affected Adversely affected proteinuria proteinuria• GFR and CrCl GFR and CrCl decrease decrease• BUN increase, may correlate w/ severityBUN increase, may correlate w/ severity• RBF compromisedRBF compromised• ARF w/ oliguria – PIH, esp. w/ abruption, DIC, HELLPARF w/ oliguria – PIH, esp. w/ abruption, DIC, HELLP

**OliguriaOliguria + + renal failurerenal failure may occur in the may occur in the absence of hypovolemiaabsence of hypovolemia. Be . Be careful w/ hydration careful w/ hydration pulmonary edemapulmonary edema**

UterineUterine

• Activity increasedActivity increased• Hyperactive/hypersensitive to oxytocinHyperactive/hypersensitive to oxytocin• Preterm labor – frequentPreterm labor – frequent• Uterine/placental blood flow – decreased by 50-70%Uterine/placental blood flow – decreased by 50-70%• Abruption – incidence increasedAbruption – incidence increased

Morbidity / MortalityMorbidity / Mortality

Maternal complications:Maternal complications:

• Leading cause of maternal death in PIH is Leading cause of maternal death in PIH is intracranial hemorrhageintracranial hemorrhage• SeizuresSeizures• Pulmonary edema Pulmonary edema • ARFARF• ProteinuriaProteinuria• Hepatic swelling with or without liver dysfunctionHepatic swelling with or without liver dysfunction• DIC DIC (usually associated with placental abruption and is uncommon (usually associated with placental abruption and is uncommon

as a primary manifestation of preeclampsia)as a primary manifestation of preeclampsia)

Morbidity / MortalityMorbidity / Mortality

Fetal complications:Fetal complications:

• Abruptio placentaeAbruptio placentae• IUGRIUGR• Premature delivery Premature delivery • Intrauterine fetal deathIntrauterine fetal death

HELLP SyndromeHELLP Syndrome

• HHemolysisemolysis• EElevated levated LLiver enzymesiver enzymes• LLow ow PPlateletslatelets

• < 36 wks< 36 wks• MalaiseMalaise (90%), (90%), epigastric painepigastric pain (90%), (90%), N/V N/V (50%)(50%)• Self-limiting Self-limiting • Multi-system failureMulti-system failure

HELLP SyndromeHELLP Syndrome

• Hemostasis is Hemostasis is not problematicnot problematic unless unless PLT < PLT < 40,00040,000

• Rate of fallRate of fall in PLT count is important in PLT count is important • Regional anesthesia - contraindicated Regional anesthesia - contraindicated fall is fall is suddensudden• PLT count PLT count normal within 72 hrs of delivery normal within 72 hrs of delivery• Thrombocytopenia may persist for longer periods.Thrombocytopenia may persist for longer periods.• Definitive cureDefinitive cure is is deliverydelivery

TreatmentTreatment

• ManagementManagement of maternal hemodynamics & prevention of of maternal hemodynamics & prevention of eclampsia are eclampsia are keykey to a favorable outcome to a favorable outcome

• MgSOMgSO44 - Rx of choice for preeclampsia. - Rx of choice for preeclampsia.

• Does not significantly reduce systemic BP at the serum Does not significantly reduce systemic BP at the serum concentration that are efficacious in treating concentration that are efficacious in treating preeclampsiapreeclampsia

• GoalsGoals• Control BPControl BP• Prevent seizuresPrevent seizures• Deliver the fetusDeliver the fetus

Controlling the HTNControlling the HTN

• HydralazineHydralazine• LabetalolLabetalol• NitroglycerinNitroglycerin• NifedipineNifedipine• EsmololEsmolol• Na Nitroprusside – risk of cyanide toxicity in the fetusNa Nitroprusside – risk of cyanide toxicity in the fetus

Preventing SeizuresPreventing Seizures

• MgSOMgSO44 - Drug of choice. Narrow therapeutic index - Drug of choice. Narrow therapeutic index

• Reduce > 50% w/o any serious maternal morbidityReduce > 50% w/o any serious maternal morbidity• 4g IV Bolus over 10 minutes, then infusion @ 1g/hr4g IV Bolus over 10 minutes, then infusion @ 1g/hr • Renal failure - rate of infusion Renal failure - rate of infusion by serum Mg levels by serum Mg levels• Plasma Level should be between 4-6 mmol/LPlasma Level should be between 4-6 mmol/L• Monitor clinical signs for toxicity Monitor clinical signs for toxicity

• Toxic:Toxic: 10 ml of 10% Ca Gluconate IV slowly10 ml of 10% Ca Gluconate IV slowly

MgSOMgSO4 4 ToxicityToxicity

• 5-10 mEq/L5-10 mEq/L – Prolonged PR, widened QRS – Prolonged PR, widened QRS• 11-14 mEq/L11-14 mEq/L – Depressed tendon reflexes – Depressed tendon reflexes• 15-24 mEq/L 15-24 mEq/L – SA, AV node block, respiratory paralysis– SA, AV node block, respiratory paralysis• >25 mEq/L - Cardiac arrest>25 mEq/L - Cardiac arrest

Anesthetic ConsiderationsAnesthetic Considerations

• Detailed preanesthetic assessment Detailed preanesthetic assessment • Focuses on Focuses on airway, fluid status, and BP controlairway, fluid status, and BP control• Lab: CBC, BUN/Cr, LFTs Lab: CBC, BUN/Cr, LFTs • Routine coagulation is NOT recommended unless there Routine coagulation is NOT recommended unless there

is clinical suspicionis clinical suspicion• PLT count - if neuraxial techniques are consideredPLT count - if neuraxial techniques are considered

Regional AnesthesiaRegional Anesthesia

• Labor epidural - advantage of a gradual onset of Labor epidural - advantage of a gradual onset of sympathetic blockade sympathetic blockade provides cardiovascular stability provides cardiovascular stability & avoids neonatal depression.& avoids neonatal depression.

• Epidurals may reduce vasospasm and HTN – may Epidurals may reduce vasospasm and HTN – may improve uteroplacental blood flowimprove uteroplacental blood flow

• Reduce risk of airway complications and avoid Reduce risk of airway complications and avoid hemodynamic alterations associated with intubationhemodynamic alterations associated with intubation

Regional (part 2)Regional (part 2)

• Neuraxial anesthesia in preeclamptic pt - still Neuraxial anesthesia in preeclamptic pt - still controversial controversial

• Many studies Many studies this is the this is the bestbest option option• National High blood Pressure Education Program National High blood Pressure Education Program

Working GroupWorking Group ““Neuraxial, epidural, spinal and combined spinal-epidural (CSE), Neuraxial, epidural, spinal and combined spinal-epidural (CSE),

techniques offer many advantages for labor analgesia and can techniques offer many advantages for labor analgesia and can be safely administered to the parturient with preeclampsia. Dilute be safely administered to the parturient with preeclampsia. Dilute epidural infusions of local anesthetic plus opioid produce epidural infusions of local anesthetic plus opioid produce adequate sensory block without motor block or clinically adequate sensory block without motor block or clinically significant sympathectomy. “significant sympathectomy. “

Regional (part 3)Regional (part 3)

• Possibility of extensive sympatholysis with profound Possibility of extensive sympatholysis with profound hypotension hypotension

decrease CO & uteroplacental perfusiondecrease CO & uteroplacental perfusion

• Single shot spinal technique Single shot spinal technique controversial controversial Recent analysis suggest that it can be used Recent analysis suggest that it can be used safetysafety in pt with in pt with

severe preeclampsiasevere preeclampsia undergoing C-section. BP decline similar undergoing C-section. BP decline similar to epidural. Hypotension can be avoided by meticulous attention to epidural. Hypotension can be avoided by meticulous attention to anesthetic technique and careful volume expansionto anesthetic technique and careful volume expansion

General Anesthetic TechniquesGeneral Anesthetic Techniques

• Laryngeal response Laryngeal response blunted by pre-treatment with blunted by pre-treatment with hydralazine, nitroglycerin or labetalolhydralazine, nitroglycerin or labetalol

• Airway edema Airway edema increased risk of difficult airway increased risk of difficult airway situationsituation

• Neuraxial techniques Neuraxial techniques preferred method, preferred method, contraindicated in the presence of coaguloapthycontraindicated in the presence of coaguloapthy

• In pt receiving MgSOIn pt receiving MgSO44, SUX activity , SUX activity potentiatedpotentiated • EnhancedEnhanced sensitivitysensitivity to non-depolarizing muscle to non-depolarizing muscle

relaxantsrelaxants• MgSOMgSO44 blunts response to vasconstrictors and inhibits blunts response to vasconstrictors and inhibits

catecholamine release after sympathetic stimulationcatecholamine release after sympathetic stimulation

Thank You!Thank You!