The Pregnant ED Patient – A Compendium of Pearls
Resident Clinical Pearl (RCP) – April 2017
Luke Taylor, R1 FMEM, Dalhousie University, Saint John, New Brunswick
Reviewed/Edited by Dr. David Lewis
Many adaptations take place in the gravid female, the end goal of each being to provide optimal growth for the fetus, as well as to protect the mother from the potential risks of labour and delivery.
It is very important to understand these changes when assessing an unwell pregnant patient. For example, a hemorrhaging patient may not show the typical signs and symptoms of tachycardia and hypotension until much later.
Vitals:
BP: Blood pressure falls earlier in pregnancy with nadir in second trimester (mean ~105/60 mmHg). Third trimester BP increases and may reach pre pregnancy levels at term.
Brought on by a reduction in SVR and multiple hormonal influences not fully understood.
HR: CO=HRxSV. The increase in CO is attributed mainly to the increase in circulating volume (30-50% above baseline). HR increases by 15-20 beats/min over non pregnant females.
*Supine position in the gravid female can lower CO by 20-30%
RR: State of relative hyperventilation. NO change in RR, however there is an increase in tidal volume resulting in a 50% increase in minute ventilation. Increased O2 consumption and demand with hypersensitivity to changes in CO2.
*60-70% of women experience a sensation of dyspnea during pregnancy
Imaging and ECG:
Must ensure imaging is necessary for management and explain risks well.
** 1 rad increases the risk of childhood malignancy by 1.5-2x above baseline.
CXR: Minimal changes to CXR in normal pregnancy but may have; prominence of the pulmonary vasculature and elevation of the diaphragm.
PoCUS: FAST doesn’t perform well in pregnant patient. Small amount of physiologic free fluid in the pelvis (posterior, lower portion of uterus), all else should be considered pathologic. Physiologic hydronephrosis and hydroureter (mostly R-sided).
CT-A: When required to rule out PE, capable of being completed at very low rad (below teratogen cut off, CT of 1-3rad is under the teratogenic cutoff of 5-10rad = 10,000 cxr or 10x CT chest
ECG: Various changes occur, may include ST and T wave changes, and presence of Q waves. The heart is rotated toward the left, resulting in a 15 to 20º left axis deviation. Marked variation in chamber volumes, especially left atrial enlargement. This can lead to stretching of the cardiac conduction pathways and predisposes to alterations in cardiac rhythm.
Routine Laboratory Tests:
CBC: Physiologic Anemia – Increased retention of Na and H2O (6-8L) leading to volume expansion combined with a slightly smaller increase in red cell mass.
Leukocytosis – Due to physiologic stress from the pregnancy itself, creates a new reference range from 9000, to as high as 25000 in healthy pregnant females (often predominately neutrophils)
PTT: Various processes result in 20% reduction of PTT and a hypercoagulable state (also helps to protect from hemorrhage during labour).
Urinalysis: Very common to have 1-3+ leukocytes, presence of blood, as well as ketones on point of care testing. Not considered pathologic unless Nitrite positive.
Creatinine: Pre-eclamptic patients may have a creatinine in the normal range, but have a drastic reduction in GFR (40%).
B-HCG: Every female of childbearing years should be considered to: Be pregnant, RH-, and have an ectopic. Studies show that 7-15% of women who (in the ED) state it is “Impossible” they are pregnant, end up being. Draw a beta HCG on every women of childbearing years regardless of LMP.
ACLS
Remember, most features are the same as when resuscitating a non-pregnant patient.
Some things to remember:
Higher risk of aspiration – Progesterone relaxes gastroesophageal sphincters and prolongs transit times throughout the intestinal tract. = Careful bag mask ventilation, do not overdo it.
Left uterine displacement (LUD)– While patient supine to provide best chest compressions possible
Medications and Dosages– Remain the same in pregnancy, vasopressors like epinephrine should still be used despite effect on uterus perfusion
Defibrillation OK– Fetus is not effected by defibrillation, low risk of arc if fetal monitors in place, do not delay.
Four minute rule– For patients whose uterus is at or above the umbilicus, prepare for cesarean delivery if no ROSC by 4mins. ** In a case series of 38 perimortem cesarean delivery (PMCDs), 12 of 20 women for whom maternal outcome was recorded had ROSC immediately after delivery.
Etiology: Must continue to think broadly, however common reasons for maternal cardiac arrest are: bleeding, heart failure, amniotic fluid embolism (AFE), and sepsis. Common maternal conditions that can lead to cardiac arrest are: preeclampsia/eclampsia, cerebrovascular events, complications from anesthesia, and thrombosis/thromboembolism.
References
http://circ.ahajournals.org/content/132/18/1747/tab-supplemental
https://radiopaedia.org/cases/chest-x-ray-in-normal-pregnancy
