Developed by Dr. Heather Flemming as part of her PG PoCUS Elective at SJRHEM.
A useful Point of Care Ultrasound (PoCUS) guide to common normal values, measurements, pathological values and quick reference tips. A pdf version is also provided in this post which can be downloaded, printed and attached to your ultrasound machine for easy access.
Reviewed 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 in the ED.
BP: Blood pressure falls earlier in pregnancy with nadir in second trimester (mean ~105/60 mmHg). In the third trimester BP increases and may reach pre pregnancy levels at term. BP is related to a reduction in SVR and multiple hormonal influences that are 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% due to a reduction in venous return which reduces stroke volume.
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 chances in CO2.
*60-70% of women experience a sensation of dyspnea during pregnancy
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 r/o 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.
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 until proven otherwise. Draw a beta HCG on every critically ill or injured women of childbearing years regardless of reported LMP.
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.
Cardiac Arrest in Pregnancy – A Scientific Statement From the American Heart Association
Up To Date – Respiratory Tract Changes in Pregnancy
Merk Manual – Physiology of Preganacy
https://radiopaedia.org/cases/chest-x-ray-in-normal-pregnancy
Social media site @CanadiEM recently featured the @CJEMonline @IFEM2 #SHoC Consensus Protocol, featuring authors from @SJRHEM among others.
So why do we need another ultrasound protocol in emergency medicine? RUSHing from the original FAST scan, playing the ACES, FOCUSing on the CAUSE and meeting our FATE, it may seem SHoCking that many of these scanning protocols are not based on disease incidence or data on their impact, but rather on expert opinion. The Sonography in Hypotension (SHoC) protocols were developed by an international group of critical care and emergency physicians, using a Delphi consensus process, based upon the actual incidence of sonographic pathology detected in previously published international prospective studies [Milne; Gaspari]. The protocols are formulated to help the clinician utilize ultrasound to confirm or exclude common causes, and guides them to consider core, supplementary and additional views, depending upon the likely cause specific to the case.
Why would I take the time to scan the aorta of a 22 year old female with hypotension, when looking for pelvic free fluid might be more appropriate? Why would I not look for lung sliding, or B lines in a breathless shocked patient? Consideration of the shock category by addressing the “4 Fs” (fluid, form, function, and filling) will provide a sense of the best initial therapy and should help guide other investigations. Differentiating cardiogenic shock (a poorly contracting, enlarged heart, widespread lung B lines, and an engorged IVC) in an elderly hypotensive breathless patient, from sepsis (a vigorously contracting, normally sized or small heart, focal or no B lines, and an empty IVC) will change the initial resuscitation plan dramatically. Differentiating cardiac tamponade from tension pneumothorax in apparent obstructive shock or cardiac arrest will lead to dramatically differing interventions.
SHoC guides the clinician towards the more likely positive findings found in hypotensive patients and during cardiac arrest, while providing flexibility to tailor other windows to the questions the clinician needs to answer. One side does not fit all. That is hardly SHoCing news. Prospective validation of ultrasound protocols is necessary, and I look forward to future analysis of the effectiveness of these protocols.
References
Scalea TM, Rodriguez A, Chiu WC, et al. Focused Assessment with Sonography for Trauma (FAST): results from an inter- national consensus conference. J Trauma 1999;46:466-72.
Labovitz AJ, Noble VE, Bierig M, Goldstein SA, Jones R, Kort S, Porter TR, Spencer KT, Tayal VS, Wei K. Focused cardiac ultrasound in the emergent setting: a consensus statement of the American Society of Echocardiography and American College of Emergency Physicians. Journal of the American Society of Echocardiography. 2010 Dec 31;23(12):1225-30.
Hernandez C, Shuler K, Hannan H, Sonyika C, Likourezos A, Marshall J. C.A.U.S.E.: cardiac arrest ultra-sound exam – a better approach to managing patients in primary non-arrhythmogenic cardiac arrest. Resuscitation 2008;76:198–206
Atkinson PR, McAuley DJ, Kendall RJ, et al. Abdominal and Cardiac Evaluation with Sonography in Shock (ACES): an approach by emergency physicians for the use of ultrasound in patients with undifferentiated hypotension. Emerg Med J 2009;26:87–91
Perera P, Mailhot T, Riley D, Mandavia D. The RUSH exam: Rapid Ultrasound in Shock in the evaluation of the critically lll. Emerg Med Clin North Am 2010;28:29 – 56
Jensen MB, Sloth E, Larsen KM, Schmidt MB: Transthoracic echocardiography for cardiopulmonary monitoring in intensive care. Eur J Anaesthesiol. 2004, 21: 700-707.
Gaspari R, Weekes A, Adhikari S, Noble VE, Nomura JT, Theodoro D, Woo M, Atkinson P, Blehar D, Brown SM, Caffery T. Emergency department point-of-care ultrasound in out-of-hospital and in-ED cardiac arrest. Resuscitation. 2016 Dec 31;109:33-9.
Milne J, Atkinson P, Lewis D, et al. (April 08, 2016) Sonography in Hypotension and Cardiac Arrest (SHoC): Rates of Abnormal Findings in Undifferentiated Hypotension and During Cardiac Arrest as a Basis for Consensus on a Hierarchical Point of Care Ultrasound Protocol. Cureus 8(4): e564. doi:10.7759/cureus.564
Sonography in Hypotension and Cardiac Arrest: The SHoC Consensus Statement
An emergency physician is a physician who is engaged in the practice of emergency medicine and demonstrates the specific set of required competencies that define this field of medical practice. The accepted route to demonstration of competence in medicine in Canada is through certification by a recognized certifying body.*
CAEP recognizes that historically many of its members are physicians who have practiced emergency medicine without formal training and certification. Many have been, and continue to be key contributors to developing emergency medicine and staffing emergency departments in Canada. CAEP acknowledges the contributions of these valued physicians and recognizes them as emergency physicians. It is CAEP’s vision going forward that physicians entering emergency practise will demonstrate their competencies by obtaining certification.
* Recognized certifying bodies in Canada are:
The Royal College of Physicians & Surgeons of Canada
The College of Family Physicians of Canada
(Emergency Physicians with equivalent non-Canadian training and certification are also recognized in Canada eg The American Board of Emergency Medicine)
It is CAEP’s vision, that by 2020 all emergency physicians in Canada will be certified in emergency medicine by a recognized certifying body.*
Toward that vision, provincial governments and Faculties of Medicine must urgently allocate resources to increase the numbers of emergency medicine postgraduate positions in recognized training programs so the Colleges are able to address the gap in human resources and training. Furthermore, physicians who have historically practiced emergency medicine without certification must be supported in their efforts to become certified. CAEP is committed to facilitate this process by cataloguing and nationally coordinating practice- and practitioner-friendly educational continuing professional development programs designed to assist non-certified physicians to be successful in their efforts.
* Recognized certifying bodies in Canada are:
The Royal College of Physicians & Surgeons of Canada
The College of Family Physicians of Canada
(Emergency physicians with equivalent non-Canadian training and certification are also recognized in Canada eg The American Board of Emergency Medicine)
We have also published on this topic, highlighting the need for more resident positions in New Brunswick and PEI. Read our paper here.
Read more from CAEP here.
iHR day is a collaboration between Horizon Health – Saint John Zone, the University of New Brunswick – Saint John Campus, the New Brunswick Community College – Saint John Campus and Dalhousie Medicine New Brunswick.
The day featured oral and poster presentations by health researchers from these four institutions, an outstanding keynote speaker, and a great opportunity to discuss health research with your colleagues. More information here
Point of care ultrasound (PoCUS) has become an established tool in the initial management of patients with undifferentiated hypotension in the emergency department (ED). Current established protocols (e.g. RUSH and ACES) were developed by expert user opinion, rather than objective, prospective data. Recently the SHoC Protocol was published, recommending 3 core scans; cardiac, lung, and IVC; plus other scans when indicated clinically. We report the abnormal ultrasound findings from our international multicenter randomized controlled trial, to assess if the recommended 3 core SHoC protocol scans were chosen appropriately for this population.
Point of care ultrasound (US) is a key adjunct in the management of trauma patients, in the form of the extended focussed assessment with sonography in trauma (E-FAST) scan. This study assessed the impact of adding an edus2 ultrasound simulator on the diagnostic capabilities of resident and attending physicians participating in simulated trauma scenarios.
Point of care ultrasonography (PoCUS) is now an established tool in the initial management of hypotensive patients in the emergency department (ED). It has been shown to be helpful in ruling out certain shock etiologies, and improving diagnostic certainty, however evidence on its benefit in the management of hypotensive patients is limited.
Point of Care Ultrasound (PoCUS) protocols are commonly used to guide resuscitation for emergency department (ED) patients with undifferentiated non-traumatic hypotension. While PoCUS has been shown to improve early diagnosis, there is a paucity of evidence for any outcome benefit. We undertook an international multicenter randomized controlled trial (RCT) to assess the impact of a PoCUS protocol on key resuscitation markers in this group. We have reported diagnostic impact and mortality elsewhere.
Patients with chronic diseases such as COPD, coronary artery disease, depression and anxiety are known to benefit from exercise. They also frequently visit the emergency department (ED). Despite the large therapeutic window and evidence supporting its role in disease management, there are few studies examining prescribing exercise in the ED. We asked: Is exercise prescription in the ED feasible and effective?
Choosing Wisely is an innovative approach to address physician and patient attitudes towards low value medical tests; however, a knowledge translation (KT) gap exists.
We aimed to quantify the baseline familiarity of emergency medicine (EM) physicians with the Choosing Wisely Canada (CWC) EM recommendations. We then assessed whether a structured KT initiative affected knowledge and awareness.
Reviewed by Dr. David Lewis and Dr. Brian Ramrattan
Problem:
Solution:
It is well known amongst health practitioners that accurate dosing in pediatrics is extremely important; even a small miscalculation can have catastrophic results, potentially even death. We double check and triple check our calculations to make sure we prescribe the correct weight based dose. This is an excellent practice, and one we should continue to be diligent with, but if we don’t give proper instructions to parents, our calculations will be in vain: in a recent study of parents observed preparing prescriptions for their children, 84% of them made a measurement error!
In this randomized control study, 2110 parents were assigned to 5 different groups in an outpatient office setting. All groups got the same prescription for amoxicillin, and the parents were observed preparing the medication for their children (three times). The groups differed in the tools provided (measuring cup, syringe, or both) and how the units were described (mls, teaspoons or both). (See below).
Across all groups, 84.4% of parents made at least one measurement error (at least a 20% under/over dose). 21% of parents more than doubled the prescribed dose. The group with the fewest errors was group I: when prescriptions were only written in mLs, and only a syringe was provided. Using the measuring cup, 43% of parents made a dosing error compared to 16% with the syringes (p<0.001).
Parents with lower health literacy and from lower socioeconomic backgrounds were more likely to make mistakes, but like those with better literacy made fewer mistakes in the syringe only group versus the groups that included cups.
When writing out pediatric liquid prescriptions, describe the medications in terms of mL and specify that the meds should be distributed with a syringe, or provide a syringe from the hospital. This study did not demonstrate whether having practice draw up medications reduced errors, however it seems prudent to have health care workers observe parents give a first dose in the ED if time permits.
