When caring for a pregnant patient, an elevated blood pressure should command the attention of the EMS clinician. It never should be ignored.
Maternal blood pressure is normal early in the pregnancy and lowers between the 20th–24th week as blood vessels relax from hormonal effects. Causes of elevated blood pressure include chronic hypertension, gestational hypertension, preeclampsia and eclampsia.
Chronic hypertension involves a patient who has known or undiagnosed hypertension before the 20th week of gestation. After 20 weeks, gestational hypertension develops in someone who previously had normal blood pressure findings. This type of hypertension isn’t associated with evidence of organ involvement or proteinuria.
Preeclampsia is associated with these pathological findings and can affect the mother’s liver, kidneys, brain, blood and lungs negatively. Preeclampsia can be dangerous to the mother and baby. It can progress to eclampsia, involving seizures, which increase fetal and maternal morbidity and mortality. This can occur antepartum, intrapartum and as many as six weeks postpartum.
Preeclampsia is associated with abnormal placenta development. The spiral arteries that are found in the endometrium don’t remodel correctly. They remain small and don’t grow to a diameter that adequately supports the placenta. The result is ischemia from the poor blood flow and damaged endothelial cells, which secrete proinflammatory proteins, which causes leaks from the vessels, increased vessel permeability, edema in the major organs (kidneys, lungs, brain, liver) and systemic edema. The blood can be affected with thrombi, damaged red blood cells and depleted platelets. Definitive care is delivery. Concomitant pathophysiology can result in placental abruption or hemorrhagic stroke.
Management
The American College of Obstetricians and Gynecologists (ACOG) and the National Association of EMS Physicians (NAEMSP) released guidance on the subject. Treatment is time critical and should be provided within 30–60 minutes. This time frame easily falls within the EMS window. Reliable directions are:
- Systolic blood pressure (SBP) 140–159 mmHg or diastolic blood pressure (DBP) 90–109 mmHg: Abnormal, possible preeclampsia. Requires foundational care (full assessment with frequent vital signs, oxygen when saturations are ≤ 94 percent, assist ventilation as needed, intravenous access for medication administration).
- SBP 140–159 mmHg or DBP 90–109 mmHg (severe features): Abnormal, preeclampsia with severe headache, blurred vision or right upper quadrant/epigastric pain. Requires foundational care and intravenous magnesium sulfate administration.
- SBP ≥ 160 mmHg or DBP ≥ 110 mmHg: Abnormal, preeclampsia even without other symptoms. Requires foundational care with an antihypertensive medication and magnesium intravenous sulfate treatment. An antihypertensive medication has the highest priority.
Although dosing of common antihypertensives (labetalol, hydralazine or nifedipine) and anticonvulsants (magnesium sulfate) is beyond the scope of this article, it should be considered in conjunction with an agency’s medical director. Indications, contraindications and side effects must be considered for each medication. The ACOG and NAEMSP guidelines offer further recommendations.
Transport should be provided, with early notification to a facility that offers obstetric services or to the most appropriate hospital, when an obstetrical center is unavailable. Rest, limited stimulation and special positioning should be considered. Improving blood return to the heart by shifting the uterus off of the inferior vena cava is important. Left side-lying or manual leftward uterine displacement is desired. Pillows and blankets can be used to wedge the patient into a lateral position.
Importance
Elevated blood pressure during pregnancy can indicate a life-threatening emergency. The clinician should understand its implications and be prepared to render timely and proper care.
