Questions of the Week for 10/31/2023
Author: Christian Gerhart
During what time frame do ductal dependent congenital heart lesions typically present?
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The most common time frame is within the first 1-2 weeks when the ductus arteriosus closes. However, there can be a wide range of time periods when the ductus closes, and any child who presents in shock at < 6 weeks old may be experiencing cardiogenic shock from an unmasked congenital lesion.
What specific assessment tools and exam can be helpful for evaluating the cyanotic neonate in the ED?
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A difference in pulses in the upper compared to lower extremities should raise suspicion for a congenital lesion. Prolonged capillary refill in a patient without fever should also be concerning for a cardiac cause of shock.
In addition to vital signs, consider an early pre and post ductal oxygen saturation as well as a right upper extremity (RUE) and lower extremity (LE) blood pressure measurement. Either a 3% difference in SpO2 between the RUE and either LE or an SpO2 <94% in either the RUE or either LE is concerning for a congenital heart lesion. A greater than 10 mmHg difference between the RUE and LE BP is also concerning for a congenital lesion.
An EKG, chest x ray and BNP should be obtained as part of the initial workup.
For most of us, interpretation of newborn vital signs is challenging. Recall that BPs for neonates within the first week of life can be remarkably low. Depending on the patient’s gestational age and days since birth, systolic pressures can be in the 60s and still be normal. You may see even lower numbers for patients who are very premature shortly after birth.
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You have a neonate who presents with what you suspect to be cardiogenic shock. Describe your initial stabilization package.
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Oxygen: be generous but actually want to avoid 100% SpO2
Prostaglandin: Dr. Robison recommends a starting dose of 0.0125 to 0.025, but you may start a bit higher at 0.05 if you are stabilizing a crashing patient before transfer.
Cautious Fluids: Use your judgement if the patient would benefit from them. If you give them start low at 5-10 mL/kg--> helpful to follow HR (if it goes up, you are in trouble and should stop them!)
Epi: 0.05 mcg/kg/min--> more in the inotropic range, want to limit SVR if possible
You decide to administer a dose of prostaglandin to a neonate you suspect is in cardiogenic shock from a congenital heart lesion. What are the most concerning side effects of this medication?
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Apnea
Especially at high doses
Hypotension and tachycardia
Need additional IV access point to resuscitate through
Your patient who received prostaglandin now requires intubation. Describe your medications for pre-intubation and induction.
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Below is what Dr. Robison recommends for an emergent pediatric cardiogenic shock intubation.
Epinephrine infusion: 0.05 mcg/kg/min, started prior to intubation at inotropic range
Small fluid bolus: 5-10 ml/kg given prior to intubation
1/10th code dose epi push (1mcg/kg): to be given with induction medications
5 mcg/kg fentanyl: used as induction agent
1 mg/kg of rocuronium: paralytic agent given in rapid sequence following IV fentanyl
What about atropine? This is definitely an option, however he finds that epinephrine provides more precise, titratable heart rate control and is less erratic than atropine.
A young woman who is approximately 7 weeks pregnant arrives with vaginal bleeding and lower abdominal pain. What ultrasound findings would assure you that she has an intrauterine pregnancy?
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There are two ultrasound findings that indicate an intrauterine pregnancy:
Yolk sac within the endometrial cavity
OR
Fetal pole with a fetal heart rate within the endometrial cavity
A gestational sac can be an early sign of an IUP but is not necessarily diagnostic. It can be hard to distinguish a gestational sac from a pseudo-gestational sac, which can sometimes be seen in an ectopic pregnancy.
A patient presents with abdominal pain who is pregnant. US shows the following (pretend that your attending labeled it for you). What is the diagnosis?
Image from Radiopedia
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This ultrasound shows an interstitial (sometimes referred to as cornual) pregnancy. This is a form of ectopic pregnancy that can be challenging to diagnose as it can be difficult to tell if it is intrauterine or not. The key ultrasound findings are an eccentric location in the myometrium in addition to a thin myometrial mantle. The myometrial mantle is measured from the outer wall of the uterus to the outer wall of the gestational sac. A measurement <8mm is very concerning for an interstitial ectopic pregnancy and these cases should be discussed with OB. You can also see the interstitial line labeled in yellow above.
A young woman who is approximately 7 weeks pregnant arrives with vaginal bleeding and lower abdominal pain. What patient characteristics would concern you for a possible heterotopic pregnancy as you take your history?
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A heterotopic pregnancy is when there is both an intrauterine as well as an ectopic pregnancy present. Risk factors are very similar to risk factors for ectopic pregnancy in general, however history of assisted reproductive techniques (ART) such as in-vitro fertilization is a unique historical characteristic that places patients at especially high risk. Other risk factors include previous damage to the fallopian tubes such as a history of pelvic inflammatory disease, previous tubal surgery, previous ectopic, or previous pelvic surgeries. In patients without risk factors, the incidence of this is quite rare and is estimated to be approximately 1 in 30,000. However, in patients with risk factors, in particular ART, the incidence can be 1 in 100 or possibly even higher.
References:
Zubrow AB, Hulman S, Kushner H, Falkner B. Determinants of blood pressure in infants admitted to neonatal intensive care units: a prospective multicenter study. Philadelphia Neonatal Blood Pressure Study Group. J Perinatol. 1995;15(6):470-479.
Strobel AM, Lu le N. The Critically Ill Infant with Congenital Heart Disease. Emerg Med Clin North Am. 2015;33(3):501-518. doi:10.1016/j.emc.2015.04.002.
Schraft E, Gottlieb M. Near fatal interstitial pregnancy. Am J Emerg Med. 2022;57:235.e5-235.e8. doi:10.1016/j.ajem.2022.04.007.
Maleki A, Khalid N, Rajesh Patel C, El-Mahdi E. The rising incidence of heterotopic pregnancy: Current perspectives and associations with in-vitro fertilization. Eur J Obstet Gynecol Reprod Biol. 2021;266:138-144. doi:10.1016/j.ejogrb.2021.09.031.
Tolandi T. Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites. UpToDate. https://www.uptodate.com/contents/ectopic-pregnancy-clinical-manifestations-and-diagnosis. Published August 1, 2023. Accessed November 8, 2023.