Clinical Tool Identifies A Pregnant Patient In Danger: Is It Helpful For EMS?


The nation’s Emergency Medical System (EMS) infrastructure occupies a vital role in society where public health, public safety and individual patient needs converge.  In light of concerning maternal outcomes the EMS professional can benefit from greater awareness of issues in this special population. In a prior post the rising maternal mortality trend in the USA was explored and though current campaigns at reversing this troublesome trend are not directed at pre-hospital providers there may be a missed opportunity in not doing so.  

A vital tool called the Maternal Early Warning Signs (MEWS) is an evidence-based tool that has been used with success in some states to improve maternal outcomes.  



Vital Signs Speak. Are you listening? 

Few in healthcare fully appreciate the importance of vital signs than those who work in the realm of emergency medical services.  In a context where little information is known about a patient, often all that is available are a set of vital signs, a visual impression of the patient’s condition and a brief exam.  The ability to integrate the information at hand, listen carefully and initiate the right course of action is at the crux of emergency response.  The skill of deciphering “sick” versus “not sick” in a matter of seconds takes time to develop.  Equanimity in the presence of a very sick patient and initiating the correct steps of care takes even more years of training and experience to attain. 

Rapid and accurate patient assessment is a skill the same as placement of an IV, chest needle decompression or CPR.  In reality, patient assessment is the most common “procedure” performed by pre-hospital professionals and in healthcare broadly.  Just like a procedure that depends strongly on motor skills, manual dexterity and knowledge of anatomy, the skill of patient assessment is fraught with potential for errors due to lack of training, paucity of experience and cognitive biases.  Patients haven’t read the text books and may communicate information about their clinical condition in an unclear manner, further adding complexity to the clinical picture. 

Learning to separate the signal from the noisewithout triggering cognitive bias is a delicate dance even for the most skilled in healthcare. Evidence-based systems, like MEWS, can be substantive tools in navigating clinical decision making toward the next steps of care in given patient populations, such as the peripartum patient.     

Physiology Matters

Understanding some basics regarding the physiology of pregnancy is a minimal competency when caring for gravid patients, but an extensive discussion is beyond the scope of this post.  There are a few changes during pregnancy that are worth mentioning in the context of MEWS and prehospital assessment.  During pregnancy the cardiovascular system undergoes significant changes with increase in blood volume as high as 50%, as well as an increase in cardiac output, yet notably a decrease in peripheral vascular resistance.  The effect typically results in an overall lower to normal blood pressure.  Although maternal blood pressures are lowest in the second trimester, that phenomenon tends to normalize by the third trimester of pregnancy.  So, any blood pressure consistently below 90 mmHg or over 160 mmHg in a gravid patient is a red flag. Furthermore, although resting heart rate increases in the gravid condition, patients are seldomly tachycardic (over 100 beats per minute).  Tachycardia over 120 beats per minute in a gravid patient should be interpreted as a sign of physiologic distress requiring transport and immediate definitive diagnosis as to the etiology.

A 30 year-old gravida 4 para 3 female at thirty weeks gestation calls 911 for nausea, vomiting, headache and right upper quadrant abdominal pain. Her vitals: Temp-98.5 degrees Fahrenheit, pulse rate of 110 beats per minute, BP- 170/110, respiratory rate is 22.

A gravid patient over twenty weeks gestation presenting with a headache and a systolic blood pressure (SBP) greater than 160 or an elevated diastolic greater than 100 should be presumed to be suffering from pre-eclampsia and transported to an appropriate facility.  Use of hydralazine or labetalol for blood pressure control and magnesium for prevention of seizures are temporizing measures that can be considered in the field, but ultimately the definitive treatment for pre-eclampsia and eclampsia is the emergent delivery of the baby.  Of note pre-eclampsia/ eclampsia can occur in post-partum patients up until about six weeks after delivery of the baby, these conditions are typically associated with severe elevations in blood pressure, headache or even seizure.  The goal for patients with suspected post-partum pre-eclampsia is to halt further morbidity and progression to an eclamptic episode (seizures + hypertension) with use of magnesium. Again, transport to an appropriate facility for treatment is imperative.  

You arrive on the scene at a local fast food place of business for a call “pregnant female collapsed”.  Employees state she entered the business appearing sluggish and had slurred speech then fell to the ground after murmuring a couple of sentences. On visual inspection you find a confused, cachectic appearing female with a gravid abdomen breathing slowly lying on the ground.  As you obtain vitals you do not notice track marks over her forearms, but you do observe her pupils are unusually small.

Potential etiologies when encountering a pregnant patient with altered mentation includes eclampsia, hypoglycemia, a post-ictal state, a toxidrome or even intracranial hemorrhage. These cases tend to be obvious even to the novice clinician with regard to identifying a major abnormality but navigating the differential diagnosis can be complicated and resource intensive. In the prehospital setting some basic tools such as a finger glucose check, assessment of pupils, interpreting the vital signs and asking some basic questions can make a substantial difference. Of particular concern, in some states such as Texas drug overdose is a rising cause of peri-partum mortality. 

A patient 36 weeks pregnant calls EMS for shortness of breath and chest pain. She has a history of mild asthma but does not appear to be wheezing on exam.  She is afebrile, pulse ox is 90% on room air and her respiratory rate is 30.

A third trimester pregnant patient may feel out of breath which is understandable given the anatomical shifts of bowel displaced toward the diaphragm.  And certainly, pre-existing conditions such as asthma can lead to wheezing and dyspnea, but it is important to understand that pregnancy is a prothrombotic state.  A gravid patient with a consistent pulse oximetry measurement less than 95% ought to trigger consideration of deep venous thrombosis / pulmonary embolism.   

The Wrap Up

Listen carefully to the information before you and understand the needs of this special population.  Listen to the patient’s words, signs and symptoms.  Some of these patients may feel so sick that they have problems communicating their condition.  At times they may come across as being too anxious or disorganized.  The seasoned clinician understands that a patient in extremis will often times have great difficulty communicating and may even experience high levels of anxiety.  It is important to step back observe the objective information and ask yourself, “What is the medically correct action to take now?” or acknowledge the chaos and ask “What can I be missing?”  Ultimately, when in doubt transfer out to the nearest appropriate facility.

We at MedCognition are developing a female patient simulator for meaningful simulation training and would greatly appreciate any thoughts the EMS community can provide. Feel free to leave comments below.