Topics in this EM Quick Hits podcast

Anand Swaminathan on tips and tricks in polytrauma (0:38)

Rohit Mohindra on diagnosis and management of toxic megacolon (7:31)

Jesse McLaren on ECG in pulmonary embolism (12:53)

Victoria Myers & Morgan Hillier on approach to the patch call (19:19)

Brit Long on when to do a CT head before LP (28:00)

Salim Rezaie on ketaBAN study (34:57)

Podcast production, editing and sound design by Anton Helman

Podcast content by Anand Swaminathan, Rohit Mohindra, Jesse McLaren, Victoria Myers, Morgan Hillier, Brit Liong and Salim Rezaie

Written summary & blog post by Kate Dillon, Anton Helman and Brit Long

Cite this podcast as: Helman, A., Swaminathan, A., Mohindra, R., McLaren, J., Myers, V. Hillier, M. EM Quick  Hits 33 – Polytrauma Tips & Tricks, Toxic Megacolon, ECG in PE, Patch Calls, CT Before LP, Nebulized Ketamine. Emergency Medicine Cases. October, 2021. https://emergencymedicinecases.com/em-quick-hits-october-2021/Accessed [date].

Tips and tricks to make your trauma care a bit smoother

  • To secure a chest tube to the chest wall quickly and easily, use the ETT holder as a temporary measure

Source: Vanessa Cardy, Twitter

  • If the FAST is negative and you still suspect intra-abdominal bleeding, but the patient cannot get to the CT scanner for whatever reason, scrutinize the tip of the liver and the left and right sub-diaphragmatic spaces as blood will often be seen first on PoCUS in these areas, especially if the patient is placed into Trendelenburg

Fluid in the subdiaphragmatic space. Source: Radiologykey.com

  • Place a pelvic binder on the stretcher before the patient arrives and and secure it on the patient ASAP, before imaging, if they are hemodynamically unstable without an obvious cause; but don’t forget to shoot a pelvic x-ray soon thereafter in case the binder has not fully reduced the fracture
  • On the initial CXR do not forget to look at the bones/joints as well as the thorax as an unexpected shoulder dislocation for example, should ideally be reduced before the patient goes to the O.R. for another reason
  • For patients who receive ketamine during their trauma resuscitation, consider starting a ketamine drip or adding a benzodiazepine (if they are hemodynamically stable) to avoid an emergence reaction from the ketamine during transport

Toxic megacolon: A tricky diagnosis

  • Definition: acute colonic dilatation >6cm involving at least the transverse colon, with signs of systemic illness
  • Common etiologies: IBD, C.Difficile colitis, CMV or parasite infections, ischemic colitis, lymphoma
  • Risk Factors: age >40, anticholinergic or narcotic medication use, electrolyte abnormalities, barium enemas or recent colonoscopy
  • Presentation: abdominal pain (not typically peritonitic early on), distension, bloody diarrhea, metabolic acidosis/alkalosis, electrolyte disturbances, elevated WBC (Note: steroids can mask symptoms)
  • Management: treat underlying cause, IV fluids, antibiotics, pressors as needed, steroids (only after consultation with specialist service)
  • Indications for Surgery: necrosis, perforation, ischemia, abdominal compartment syndrome, end organ injury or worsening clinical status

=>Bottom line: the triad of bloody diarrhea, belly pain and distention in someone with a colitis history of any kind, especially if they’ve had a recent colonoscopy, should spark a consideration for Toxic megacolon, as mortality is up to 80% if not treated quickly

  1. Desai J, Elnaggar M, Hanfy AA, Doshi R. Toxic Megacolon: Background, Pathophysiology, Management Challenges and Solutions. Clin Exp Gastroenterol. 2020 May 19;13:203-210.
  2. Autenrieth, D.M. and Baumgart, D.C. (2012), Toxic megacolon. Inflamm Bowel Dis, 18: 584-591.

Why the ECG is so important in the diagnosis and management pulmonary embolism

  • ECG is not included in pulmonary embolism (PE) clinical guidelines and decision making tools (Wells Criteria, YEARS Algorithm) and can be normal in PE, however it can help detect complications of PE like acute right ventricular (RV) strain quickly at the bedside
  • Signs of RV Strain on ECG (sinus tachycardia, new atrial fibrillation, new RBBB, right axis deviation, T-wave inversion in anterior and inferior leads) and “classic” patterns like S1Q3T3 are not sensitive or specific for PE, and can be seen in other conditions like chronic pulmonary hypertension
  • Signs of acute RV strain on ECG can influence initial resuscitation, diagnosis and management in suspected PE as RV strain in those with PE indicates a high risk, high mortality PE that might deteriorate without timely and appropriate treatment
  • ECG signs of acute RV strain can influence the differential diagnosis, forcing clinicians to consider PE as a diagnosis and preventing premature closure in patients where PEs are often missed (those without risk factors, with COPD/CFH or with chest pain and a positive troponin or others where the diagnosis is not considered)
  • Though not a separate component in risk stratification tools, ECGs (alongside history, physical and other bedside tests) can influence the clinical gestalt of the “PE most likely diagnosis” component of these tools
  • Empiric treatment with heparin should be considered in patients with RV strain with high pretest probability for PE while awaiting imaging

=>Bottom Line: though signs of RV strain on ECG are not sensitive or specific for PE, as a rapid point of care test ECG changes can force clinicians to consider the diagnosis of PE in otherwise low risk patients, influence management considerations in undifferentiated patients, and contribute to the clinician’s gestalt in the context of clinical decision making tools; additionally in those patients where PE is suspected RV strain on ECG suggests a higher-risk PE and can influence management considerations

For examples of ECGs in pulmonary embolism and right heart strain visit ECG Cases 26

  1. Marchick MR, Courtney DM, Kabrhel C, et al. 12-lead ECG findings of pulmonary hypertension occur more frequently in emergency department patients with pulmonary embolism than in patients without pulmonary embolism. Ann Emerg Med 2010;55:331-335
  2. Kosuge M, Ebina T, Hibi K, et al. Differences in negative T waves between acute pulmonary embolism and acute coronary syndrome. Circ J 2014;78: 483-489
  3. Qaddoura A, Digby GC, Kabali C, et al. The value of electrocardiography in prognosticating clinical deterioration and mortality in acute pulmonary embolism: a systematic review and meta-analysis. Clin Cardiol 2017 Oct;40(10):814-824
  4. Daniel KR, Courtney DM, Kline JA. Assessment of cardiac stress from massive pulmonary embolism with 12-lead ECG. Chest 2001 Aug;120(2):474-81
  5. Harihara P, Dudzinski DM, Okechuwku I, et al. Association between electrocardiographic findings, right heart strain, and short-term adverse clinical events in patients with acute pulmonary embolism. Clin Cardiol 2015 Apr;38(4):236-42
  6. Shopp JD, Stewart LK, Emmett TW, et al. Findings from 12-lead electrocardiography that predict circulatory shock from pulmonary embolism: systematic review and meta-analysis. Acad Emerg Med 2015 Oct;22(10):1127-1137

Approach to the patch call for cardiac arrests and termination of resuscitation guide

  • Two main questions when answering a patch call:
    1. Is there something paramedics can do on the scene beyond ACLS that we can advise on? Consider what is on the truck which usually includes: epinephrine, amiodarone, lidocaine, calcium gluconate, normal saline, glucagon, dopamine, bicarb, defibrillator (maybe two) and airway equipment
    2. What can we add in the resuscitation bay if they are transported to hospital? Lysis, advanced airway, central and peripheral access, ultrasound and advanced procedures like pericardiocentesis
  • What you need to know to make a decision about management: age, PMHx, recent history (24h), last seen well, unwitnessed or witnessed arrest, bystander CPR, no flow time (down, no CPR), low flow time (CPR ongoing), was patient ever in a shockable rhythm, end tidal CO2 and its trend (>10 after intubation, or >20 after 20 min of CPR may predict ROSC), ask what medics think
  • Termination of Resuscitation Guide: 
    • unwitnessed arrest
    • always unshockable rhythm
    • ROSC never occurred
    • if all three are present it has a 99.5% predictive value for death
  • Specific Management Scenarios:
    • Refractory VT or VF: consider vector change or dual sequential defibrillation
    • TCA Overdose: advise bicarb if QRS is widened
    • Pseudo PEA: PEA with high end tidal CO2 and narrow complex rhythm, patient may have a pulse that is not palpable due to profound hypotension, consider transport in this scenario

=>Bottom Line: ask yourself is there anything extra that paramedics can do on scene, what will transporting to hospital add, think about special scenarios and consider Pseudo PEA, most importantly ask the paramedics what they think

Episode 131 – PEA arrest, PseudoPEA and PREM with Rob Simard & Scott Weingart

  1. Morrison LJ, Visentin LM, Kiss A, Theriault R, Eby D, Vermeulen M, Sherbino J, Verbeek PR; TOR Investigators. Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest. N Engl J Med. 2006 Aug 3;355(5):478-87. doi: 10.1056/NEJMoa052620.

When to do a CT before a lumbar puncture

  • Lumbar puncture (LP) is important for the diagnosis of meningitis and to maximize the chances of isolating the offending organism, needs to be done before or shortly after the procedure
  • Though there is a risk of brainstem herniation in patients with cerebral edema and increased ICP, performing a CT prior to every LP increases cost, radiation exposure and most importantly can delay the start of antibiotics
  • Studies suggest there is some association with LP and brainstem herniation with intracranial mass effect but the risk is small and meningitis itself in sick patients can cause brainstem herniation even in patients with a normal CT scan
  • In patients with low likelihood of an abnormal CT who are <60 years, not immunocompromised, have no CNS disease, no seizure in past week and have a normal neurologic exam (including mental status), the risk of herniation after LP is low
  • Waiting for a CT scan prior to administering antibiotics can delay antibiotics and observational data suggests that mortality increases by 30% for patients with meningitis with each hour delay in antibiotic administration

=>Bottom Line: if you suspect meningitis, start antibiotics early and perform the LP, clinical decision rules can provide some help in determining who should get a CT scan but have not been validated; if you are going to get a CT scan consider administering antibiotics before the CT

  1. Michael B, Menezes BF, Cunniffe J, Miller A, Kneen R, Francis G, et al. Effect of delayed lumbar punctures on the diagnosis of acute bacterial meningitis in adults. Emerg Med J, 2010; 27: 433-8.
  2. Aronin SI, Peduzzi P, and Quagliarello VJ. Community-acquired bacterial meningitis: risk stratification for adverse clinical outcome and effect of antibiotic timing. Ann Intern Med, 1998; 129: 862-9.
  3. Proulx N, Frechette D, Toye B, Chan J, and Kravcik S. Delays in the administration of antibiotics are associated with mortality from adult acute bacterial meningitis. QJM, 2005; 98: 291-8.
  4. Koster-Rasmussen R, Korshin A, and Meyer CN. Antibiotic treatment delay and outcome in acute bacterial meningitis. J Infect, 2008; 57: 449-54.
  5. van Crevel H, Hijdra A, and de Gans J. Lumbar puncture and the risk of herniation: when should we first perform CT? J Neurol, 2002; 249: 129-37.
  6. Gopal AK, Whitehouse JD, Simel DL, and Corey GR. Cranial computed tomography before lumbar puncture: a prospective clinical evaluation. Arch Intern Med, 1999; 159: 2681-5.
  7. Hasbun R, Abrahams J, Jekel J, and Quagliarello VJ. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med, 2001; 345: 1727-33.
  8. Shetty AK, Desselle BC, Craver RD, and Steele RW. Fatal cerebral herniation after lumbar puncture in a patient with a normal computed tomography scan. Pediatrics, 1999; 103: 1284-7.
  9. Zaidat OO, and Suarez JI. Computed tomography for predicting complications of lumbar puncture. JAMA, 2000; 283: 1004.
  10. Joffe AR. Lumbar puncture and brain herniation in acute bacterial meningitis: a review. J Intensive Care Med, 2007; 22: 194-207.
  11. Oliver WJ, Shope TC, and Kuhns LR. Fatal lumbar puncture: fact versus fiction–an approach to a clinical dilemma. Pediatrics, 2003; 112: e174-6.
  12. Glimaker M, Johansson B, Grindborg O, Bottai M, Lindquist L, and Sjolin J. Adult bacterial meningitis: earlier treatment and improved outcome following guideline revision promoting prompt lumbar puncture. Clin Infect Dis, 2015; 60: 1162-9.

Nebulized ketamine: ketaBAN study

  • This RCT was the first trial to compare the analgesic efficacy and safety of nebulized ketamine at three different sub-dissociative doses in ED patients presenting with acute and chronic painful conditions
  • Three doses were compared (0.75mg/kg, 1.0 mg/kg, 1.5mg/kg) and patients could receive up to three doses through a breath activated nebulizer (BAN) which has 20-40% bioavailability compared to the IV route and a duration of action of 20-40 minutes
  • Primary outcome: difference in pain scores on an 11 point scale at 30 minutes
  • Population: 120 adult patients (40 per group) presenting to the ED with an acute or chronic pain condition
  • Results: there was no significant difference between the three dosing regimens with respect to change in pain scores (mean change of 4.1 on the pain scale at 30 minutes, and 5 points at 120 minutes), 15 patients received rescue opioid analgesia, there were no serious adverse events and 25% of patients experienced psychoperceptual effects
  • Limitations: there is no comparison to placebo or other analgesic medications in this trial, and that there was no other analgesic given as a first line agent for pain relief
  • Consider: though we cannot directly compare different studies, the psychopeceptual effects appear to be lower in nebulized ketamine (25%) than those seen with sub-dissociative IV ketamine slow infusion (54%) and IV push ketamine (92%) in previous studies and fewer patients needed opioid rescue analgesia with nebulized ketamine (13%) compared to IV ketamine (19%)

=>Bottom Line: 0.75mg/kg of nebulized ketamine through a BAN is efficacious and safe in controlling acute pain in the ED, and there appears to be a signal for decreased psychoperceptual effects and need for rescue analgesia compared to IV ketamine, though these would need to be studied in direct comparison to one another

  1. Dove D et al. Comparison of Nebulized Ketamine at Three Different Dosing Regimens for Treating Painful Conditions in the Emergency Department: A Prospective, Randomized, Double-Blind Clinical Trial. Ann Emerg Med 2021.
  2. Motov S et al. Intravenous Subdissociative-Dose Ketamine Versus Morphine for Analgesia in the Emergency Department: A randomized Controlled Trial. Ann Emerg Med 2015.

None of the authors have any conflicts of interest to declare