Pediatric Advanced Life Support - PALS Core Testing Case Scenario 9: Supraventricular Tachycardia (Adolescent; Unstable)
Prehospital: You are dispatched to a house where a 12 year old boy has lethargy, tachypnea, and a racing heart.
ED: An ambulance is en route to the emergency department with a 12 year old boy with lethargy, tachypnea, and a racing heart.
General Inpatient Unit: You are called to examine a 12 year old boy with lethargy, tachypnea, and a racing heart.
ICU: You are called to the bedside of a 12 year old boy who says he has a racing heart now and has lethargy
Heart rate: 235/min
Blood pressure: 75/55 mm Hg
Respiratory rate: 34/min
Spo2: 92% on room air
Weight: 50 kg
Age: 12 years
Scenario Overview and Learning Objectives
Scenario Overview: Emphasis should be on diagnosis and management of supraventricular tachycardia (SVT) in an unstable patient, including possible rapid bolus administration of adenosine (only if intravenous IV/intraosseous IO access is readily available) and the safe delivery of synchronized cardioversion using appropriate doses. Vagal maneuvers may be performed while preparing adenosine or while preparing for synchronized cardioversion but should not delay intervention. If time allows, the instructor may briefly discuss the need for expert consultation before administering a precardioversion sedative to a child with hemodynamic instability.
Scenario -Specific Objectives
Differentiates between SVT and sinus tachycardia; In this scenario, the child has instable SVT
Describes potential vagal maneuvers used for a child with SVT; potential maneuvers used in children include blowing through an obstructed straw and carotid sinus massage
Demonstrates the proper rapid bolus technique to administer adenosine
Discuss indications for synchronized cardioversion; in this scenario, the child has poor perfusion, including hypotension, acutely altered mental status (new lethargy), and signs of shock
Demonstrate safe delivery of synchronized cardioversion with appropriate dose in a patient with SVT and poor perfusion
Evaluate - Initial Impression (Pediatric Assessment Triangle)
Appearance: Moaning, minimal response to caregivers
Breathing: Increased rate and effort, including nasal flaring
Circulation: Pale and mottled
Immediate intervention needed
Activate the emergency response system. Emergency medical services requests additional assistance if needed. Administer 100% oxygen by norebreathing face mask Apply cardiac monitor Apply pulse oximeter
Evaluate - Primary Assessment
Focused on Assessment Needed to Support Airway, Oxygenation, Ventilation, and Perfusion
Breathing: Respiratory rate 34/min; Spo2 92% before supplementary oxygen and 100% after; crackles throughout lung fields
Circulation: Heart rate 235/min; weak central pulses, thread peripheral pulses; cool/mottled skin; capillary refill about 6 seconds; blood pressure 75/55 mm Hg
Disability: Deferred until after successful rhythm conversion
Exposure: Temperature 37.6 C (99.7 F)
Weight: 50 kg
Altered level of consciousness
Narrow complex tachycardia/SVT with a pulse and poor perfusion
Respiratory distress vs respiratory failure
Establish IV/IO access if possible but do not delay cardioversion if IV/IO access is not readily available.
Guide child to perform vagal maneuvers if they do not delay adenosine or cardioversion
If functional IV is in place or is established immediately, administer adenosine
-Begin recording continuous rhythm strip.
-Give adenosine 0.1 mg/kg (max 6 mg) IV/IO by rapid bolus followed by rapid saline flush.
-If first dose of adenosine is unsuccessful, administer adenosine 0.2 mg/kg rapid bolus (max 12 mg), if it can be given more rapidly than synchronized cardioversion. Ensure that rapid bolus technique is used to administer the drug.
-If adenosine is ineffective, provide immediate synchronized cardioversion.
Deliver synchronized cardioversion as soon as it is available, unless other therapies (eg, adenosine) have worked by the time synchronized cardioversion can be delivered. (Note: Don not delay cardioversion to attempt other therapies if synchronized cardioversion can be provided immediately)
-If functional IV/IO access and expertise is immediately available, provide sedation before cardioversion if it won’t delay cardioversion. Use caution; expertise is required toa void worsening hemodynamic instability.
-As soon as a monitor/defibrillator arrives, attach pads and begin recording the rhythm strip
-“Clear” and perform synchronized cardioversion (0.5 to 1 J/kg,)
-If Synchronized cardioversion is unsuccessful, “clear” and perform synchronized cardioversion with 2 J/kg.
Prepare to assist ventilation (with bag mask device) if needed.
Evaluate - Secondary Assessment
Deferred Until After Rhythm Conversion
Signs and symptoms: Tachycardia; lethargy; hypotension
Allergies: None known
Past medical history: History of SVT about 4 years ago
Last meal: 6 hours ago
Events (onset): Acute onset 30 minutes ago
Repeat vital signs after successful rhythm conversion: Heart rate 104/min; sinus rhythm; respiratory rate 28/min; Spo2 100% on 100%oxygen by nonrebreathing mask; blood pressure 100/60 mm Hg
Head, eyes, ears, nose and throat/neck: Clear; no audible breath sounds
Heart and lungs: Sinus rhythm; central and peripheral pulses strong; capillary refill 3 seconds; no murmur, gallop, or rub appreciated; fine scattered crackles at bases on auscultation
Abdomen: Liver not palpable below the costal margin
Extremities: Cool peripherally
Neurologic: Cries out in pain with cardioversion; opens eyes and moves spontaneously, answering words or short phrases
Point-of-care (POC) glucose concentration (see below)
If no rhythm conversion or delay in administering adenosine or cardioversion
Vital signs: Heart rate 235/min; weak central pulses, peripheral pulses barely palpable; cool/mottled skin; capillary refill about 6 seconds; respiratory rate 34/min; Spo2 93% despite 100% oxygen via nonrebreathing mask; crackles throughout lung fields; blood pressure 72/54 mm Hg
SVT with poor perfusion converts to sinus rhythm if rapid adenosine or cardioversion is provided
After rhythm conversion
-Reassess and monitor patient’s cardiorespiratory status
*Evaluate for signs of heart failure (enlarged live, extra heart sounds or murmurs, crackles, rales).
-Prepare to insert advanced airway if needed.
-Wean supplementary oxygen as tolerated if child stabilizes
-Obtain 12 lead electrocardiogram (ECG)
-Check glucose with POC testing
Evaluate - Diagnostic Assessments
Perform Throughout the Evaluation of the Patient as Appropriate
Chest x-ray, 12 lead ECG in SVT and in sinus rhythm
Although laboratory test are generally not appropriate during the immediate management, a blood glucose concentration should be checked as soon as reasonably possible in critically ill infants and children. Hypoglycemia should be treated immediately.
Laboratory studies (other than POC glucose testing) are deferred until rhythm is converted and systemic perfusion and hemodynamic function are improved.