CanPoCUS Core Course – Saint John – May 12, 2023
CanPoCUS IP School – Saint John – May 13, 2023
Resuscitative TEE – the whats, the whys and the hows…. A brief review of the literature, examples of use and a proposed cardiac arrest protocol
Professor, Dalhousie Department of Emergency Medicine
Download Slides – PoCUS Rounds – TEE – Nov 2022
http://pie.med.utoronto.ca/tee/
ACEP NOW – How to Perform Resuscitative Transesophageal Echocardiography in the Emergency Department
Dr. Jill Carter Dalhousie EM Resident
Dr. David Lewis
Dr. Rawan AlRashed & Dr. Kyle Traboulsee
Dr. Victoria Landry, R3
Integrated Family Medicine Emergency Medicine Program
Saint John, NB
Edited by Dr. Rawan AlRashed, PoCUS fellow
Copyedited by Dr. Mandy Peach
PoCUS use by the emergency physician for the diagnosis of uncomplicated intrauterine pregnancy have been proven to be affective in expiditing patient management and decreasing the length of stay in the emergency department. In a metanlaysis done by Stein et.al. emergency physiscain performed PoCUS was found to be 99.3% sensitive in ruling out ectopic pregnancy by detecting an Intauterine pregnancy (IUP). In this review, ultrasound findings in the first trimester will be highlighted.
Indication: Confirmed or suspected pregnancy with abdominal pain, vaginal bleeding, syncope, or hypotension(2)
Start with trans-abdominal ultrasound (TAUS) (1,2)
Then Consider the use of transvaginal ultrasound (TVUS) if available, and qualified to use (1)
General principles (1)
Figure 1 – Longitudinal/sagittal view (TAUS): (1)
Figure 2 – Transverse view (TAUS): (1)
Discrimination zone (βHCG levels below which you cannot see an IUP)(2, 3)
Inutrauterine pregnancy
Figure 3 – Double ring sign(1)
Figure 4 – Double ring sign(4)
Figure 5 – Fetal pole(1)
Mean sac diameter
Crown-rump length (CRL) = Top of skull to base of pelvis(1)
Fetal cardiac activity = proof of live IUP(1)
No definitive intrauterine pregnancy (NDIUP) (2)
DDx for NDIUP(2):
Threatened abortion: abnormal bleeding during pregnancy; normal IUP on US(3)
Inevitable abortion: vaginal bleeding with open os; normal IUP or product of conception (POC) near cervix on US(3)
Incomplete abortion: open os with retained POC; US shows anything from debris to embryo; abnormal uterine contents confirms dx(1)
Complete abortion: empty uterus + positive βHCG +/- closed os; same findings as for ectopic therefore requires formal US + serial βHCG(1)
Ectopic pregnancy (3)
Corpus luteal cyst(2,3)
Blighted ovum (anembryonic pregnancy)(1,2)
Molar pregnancy (1,3)
Figure 7 – Extrauterine pregnancy(1)
Figure 8 – Normal myometrial mantle(1)
Figure 9 – Cornual ectopic pregnancy(1)
Figure 10 – Clinical application(2)
References:
Dr. Renee Kinden, PGY2 EM
Victoria Mercer, Clinical Clerk 3, DMNB
Reviewed and Copyedited by Dr. Mandy Peach
Rib fractures are a frequent presentation in the ED, occuring in approximately 10% of all injured patients with the primary causes being blunt chest trauma and MVAs(1,2). The mainstay of treatment for rib fractures is analgesic control(1). When pain cannot be adequately managed, the patient is at a heightened risk of hypoventilation due to decreased thoracic mobility and secretion clearance, predisposing the patient to significant atelectasis(1,2).
Historically the pain from rib fractures has been managed with acetaminophen or NSAIDS and if these do not sufficiently alleviate the pain, opioids are used(1,3). Unfortunately, these methods often do not provide adequate pain control or in the case of opioids, come with a myriad of side effects such as nausea, vomiting, constipation, respiratory depression and the potential for dependency and abuse (1,4).
An alternative to traditional methods include regional techniques such as paravertebral or epidural nerve blocks. These interventions have been shown to effectively control pain in rib fractures(3,4). The downside to these interventions include being technically challenging and time consuming with significant complication risks and contraindications such as coagulation disorders (1,3).
The solution? A serratus anterior block
An ultrasound guided blockade of the lateral cutaneous branches of the thoracic intercostal nerves was first described by Blanco et al. in 2013 for patients following breast surgery to manage their postoperative pain(5). This procedure has been adopted by many emergency departments for its convenience and practicality compared to epidural or paravertebral nerve blocks(3).
Serratus anterior blocks are less invasive and considerably more practical in the ED setting, providing paresthesia to the ipsilateral hemithorax for 12-36 hours (6).
The only absolute contraindications are patient refusal, allergy to local anesthetic and local infection(1).
Complications of a serratus anterior block include pneumothorax, vascular puncture, nerve damage, failure/inadequate block, local anesthetic toxicity and infection(1).
Serratus anterior blocks are only effective for the anterior two-thirds of the chest wall (3).
Figure 1. Ultrasound image of serratus anterior muscle and surrounding tissues with superficial or deep needle guides. Image from Thiruvenkatarajan V, Cruz Eng H, Adhikary SD. An update on regional analgesia for rib fractures. Current Opinion in Anaesthesiology. 2018;31(5):601–607.
How do you do it?
The procedure is usually performed with the patient laying supine however the patient could also lay in a lateral decubitus position (1,3). Using a high frequency linear ultrasound probe (6-13MHz), identify the serratus anterior and latissimus dorsi muscles over the fifth rib in the mid-axillary line(1,3). Using an in-plane approach, insert the needle either superficial or deep to the serratus anterior and confirm correct needle placement by visualizing anaesthetic spread via ultrasound(1,3). According to May et al., superficial spreading tends to have a longer lasting analgesic effect(1). Place and secure a catheter to infuse the remainder of the bolus(1,3). Thiruvenkatarajan et al. recommend a bolus of 40ml of 0.25% levobupivacaine and a 50mm 18G Tuohy catheter needle(3).
See this excellent review by Dr. David Lewis on identifying rib fractures and their complications using ultrasound (start 3:08) as well as a review of the block and procedure (start 8:00)
References
PoCUS Fellow
Dalhousie University Department of Emergency Medicine