Handling Hypertensive Crisis
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Transcript of Handling Hypertensive Crisis
HANDLING HYPERTENSIVE CRISIS
IN PREGNANCY
OVERVIEW
Hypertension during pregnancy includes a
number of condition and occurs in 6 - 8% of
all pregnancies. These conditions include
gestational hypertension, pre eclampsia /
eclampsia, and chronic hypertension and are
responsible for considerable maternal and
perinatal morbidity and mortality.
Definitions
Hypertension
Blood pressure taken in the sitting position
(with the right arm horizontal) that is
persistently recorded as being more than
30 mmHg systolic and/or more than
15 mmHg diastolic above pre-pregnancy
or early pregnancy value.
Definitions
In the absence of knowledge of pre-
pregnancy or early pregnancy values,
>140 mmHg systolic and or > 90 mmHg
diastolic (diastolic blood pressure is
recorded with disappearance of the
Korotkoff V sound)
Definitions
Proteinuria
Urine protein that is > 300 mg/24 hours
collection or a spot urine protein : creatinine
ratio > 25 mg/mmol are the two recognised
determinants of proteinuria.
Semi quantification by dipstick testing may
be unreliable
Definitions
Oedema
Oedema is no longer included in the definition
of pre eclampsia as it occurs equally in women
with and without this condition.
CLASSIFICATION OF
HYPERTENSION IN
PREGNANCY
Gestational Hypertension
Development of an elevated blood pressure
after 20 weeks of pregnancy or in the first 24
hours postpartum. No other signs of
symptoms of pre eclampsia or evidence of
hypertensive vascular disease is present.
Resolution of blood pressure elevation occurs
by 12 weeks postpartum.
Pre eclampsia
Mild pre eclampsia
- onset of mild hypertension (an increase of 20
mmHg systolic and or more than 10 mmHg
diastolic)
- proteinuria
- uncomplicated by neurologic symptoms or
criteria for the diagnosis of severe pre
eclampsia
Severe Pre-eclampsia
Diagnosed when
Blood pressure > 170 mmHg systolic and/or
110 mmHg diastolic
The diagnosis should also be considered in
women with lesser degrees of hypertension,
but who have on or more of the following:-
Severe Pre-eclampsia
Severe proteinuria (> 5 gm / 24 hours)
Oliguria (< 400 ml in 24 hours)
CNS dysfunction (severe headache, blurred
vision, changing sensorium)
Thrombocytopenia
Liver disease
Pulmonary oedema
IUGR
Eclampsia
The occurrence of convulsions or coma
(not caused by trauma or coincidental
neurologic disease such as epilepsy) in
woman chose condition also fulfils the
criteria for the diagnosis of pre eclampsia
Defining a Hypertensive Emergency /
Crisis
Is a matter of some debate
Blood pressure above 200/115 mmHg
? above 170/110 mmHg
? Rate of change in blood pressure is
what precipitates the crisis, as opposed
to the absolute blood pressure reading
Pathophysiology of Hypertensive Crisis
The true pathophysiology is obscure
Prominent feature seems to be loss of
cerebrovascular autoregulation, resulting in
hypertensive encephalopathy once the upper
limits of cerebral perfusion pressure are
exceeded
Rapid control of blood pressure is needed
even more because of the risks of placental
abruption and stroke
Minimizing Organ Damage
Most important clinical objective
In non pregnant state: Brain
In obstetric cases: the major morbidity and
mortality result from cardiac and renal, as
well as cerebrovascular damage
Fetal morbidity and mortality is often directly
linked to the maternal condition.
Minimizing Organ Damage
With restoration of acceptable blood
pressures, generally in the range of 140 to
150 mmHg systolic and 90 to 100 mmHg
diastolic, cardiac dysfunction begins to
reverse, renal function tends to improve, and
the restoration of cerebral autoregulatory
lessen the likelihood of stroke
Other Causes
Need to rule out other cause of hypertensive
crisis:-
Frequently, chronic hypertension of severe
pre eclampsia defines the underlying “cause”
of severe hypertension, however other
diagnosis such as uncontrolled
hyperthyroidism or pheochromocytoma,
should not be overlooked.
Regimen to Lower
Blood Pressure Safely
It is imperative that the blood pressure be
lowered in a measured and safe manner, not
to exceed a drop of 25% to 30% in the first
60 minutes, and not to drop below 150/95
mmHg
Too swift or too dramatic a reduction in blood
pressure can have untoward consequences
for both mother and fetus, i.e.
Regimen to Lower
Blood Pressure Safely
Maternal myocardial or cerebral
infarction
Acute fetal distress secondary to
uteroplacental underperfusion
Regimen to Lower
Blood Pressure Safely
Short-acting intravenous agents are
recommended to treat hypertensive
emergencies
Oral or sublingual compound are to be
avoided because they are more likely to
cause precipitous and erratic drop of blood
pressure
Regimen to Lower
Blood Pressure Safely
Pulmonary oedema is not uncommon,
due to capillary leakage and myocardial
dysfunction. Use of frusemide will best
allow for improvement of the clinical
picture in a timely manner
Acute Management Steps
Critical care facilities required
Patient should be cared for in an intensive
care unit (or labour and delivery unit with
critical care capabilities). In most institutions,
such management will include participation of
anesthesiologists, maternal fetal medicine
specialists and nurses with critical care
expertise.
Acute Management Steps
Delivery considerations
During initial management, the patient should
have continuous fetal heart rate monitoring.
It is often not possible to prolonged a
pregnancy that is remote from term.
Delivery decision will need to balance
prematurity risks against maternal risks
of continuing the pregnancy.
Use of Glucocorticoids
Hypertension in not a contraindication to
glucocorticoids for accelerating lung
maturation in the fetus and minimizing
neonatal risk of intracranial hemorrhage and
necrotizing enterocolitis.
Adjusting for gestational age, neonates of
preeclamptic mothers are afforded no
additional maturity compared with neonates
born prematurely for others reasons.
Use of Glucocorticoids
Delay of delivery for 48 to 72 hours may
not be possible in many cases,
however.
Once the patient is stabilized, delivery
must be considered
Drug Therapy
Intravenous fluids (Hartmann’s solution) at
100 -125 ml per hour
5 – 10 mg Hydralazine, given intravenously
as a bolus over 5 – 10 minutes, then by
continuous infusion at 5 mg/hour, with
adjustment of rate every 30 minutes until BP
140/90 mmHg to 160/95 mmHg
Reactive tachycardia with hydralazine may
necessitate use of IV beta blockers
Drug Therapy
The second agent of choice for the acute
treatment of hypertension is oral nifedipine.
Side effect of headache is frequent.
Occasionally hypertension resistant to
hydralazine and nifedipine requires other
drugs eg. Nitroproside or GTN
Drug Therapy
Level 1 evidence indicates that Magnesium
sulphate is the superior drug to use in the
prevention and the treatment of eclamptic
seizures.
The Magpie Trial found the risk of eclampsia
was halved and the risk of placental abruption
and overall maternal deaths were reduced in
women treated with Mg sulphate compared to
a control group.
Drug Therapy
In most cases, however, to exclude a
diagnosis of pre-eclampsia in a timely
manner is nearly impossible, hence
Magnesium sulphate is recommended,
in addition to continue with
antihypertensive to maintain BP control.
Magnesium sulpate Regime
It is best administered intravenously,
preferably through an infusion pump
apparatus. A loading dose of 4 to 6 gm is
given as a 20% solution over 15 to 20
minutes. In a patient with normal renal
function, a rate of 2gm per hour is
appropriate, but may need to be reduced if
acute renal failure ensues.
Delivery Decision
Vaginal delivery in often less
hemodynamically stressful for the mother,
but no always practical.
Many cases are remote from term and non
vertex presentation or uterine cervix is
unfavorable for induction, or a protracted
attempt at labor induction may not be
prudent.
Delivery Decision - cont
Often there is present of some degree
uteroplacental insufficiency. Altered placental
function, combine with extreme prematurity,
often results in the fetus being unable to
tolerate labour for long, necessitating
emergency Caesarean delivery.
The anaesthetist will review the optimal
anaesthesia technique.
Postpartum Management
With the delivery of the fetus, there may be a
temptation to be less rigorous in maintaining
blood pressure control during the post-partum
period.
This may be acceptable in patients with
chronic hypertension, as these patients
better tolerate higher blood pressures and
still maintain appropriate cerebral vascular
autoregulation.
Postpartum Management
For women who were previously normotensive, or who had superimposed preeclampsia, more vigorous control of blood pressure is recommended, especially if they show any degree of thrombocytopenia or pulmonary oedema.
The rationale relates to cerebral perfusion pressures and risk of stroke, and the risks of worsening pulmonary oedema in the setting of increased capillary hydrostatic pressure and reduced colloid osmotic pressure
Postpartum Management
Continuation of Mg sulphate is
recommended for patients with
superimposed pre-eclampsia until
obvious signs of disease resolution, and
for a minimum of 24 hours.
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