Webinar #16 Lecture: CODE BLUE: DECODING CARDIAC CYANOTIC EMERGENCIES

OUTLINE:

1. Definition of cyanosis
2. Recognition and Management
   1. Cyanotic emergencies in neonatal period
   1. Cyanotic emergency in infants and older children

CYANOSIS

• Comes from the word “Cyan” meaning blue
• It is clinically defined as bluish discoloration of the skin and mucous membranes
• Defined as ≥ 5 grams/dl reduced hemoglobin
• Clinically apparent cyanosis occurs when the oxygen saturation is <85 %  but may be lower in the presence of severe anemia
• The presence of the window of cyanosis that is not clinically apparent has lead to the missed diagnosis of some of the critical cyanotic heart diseases, hence, ideally pulse oximetry for all neonates before discharge.
• Cyanosis in any child, especially in neonates warrants prompt investigation regarding the cause of cyanosis. Most commonly, the causes are intrapulmonary issues (V/Q mismatch), right to left intracardiac shunts or in rare cases hemoglobinopathies

Types of cardiac cyanotic emergencies by age group:

• Neonatal period: neonates with critical cyanotic heart disease
  • dTGA IVS
  • Pulmonary Atresia
  • Tricuspid Atresia
  • TAPVC with obstructed inter atrial communication
• Older infants and children with Cyanotic CHD

• Hypercyanotic spells
  • TOF with severe PS
  • DORV with severe PS
  • Single ventricle with Severe PS

NEONATAL CYANOSIS IS A MEDICAL EMERGENCY!

It is very important to differentiate PULMONARY vs CARDIAC etiology

• Hyperoxia test is useful to differentiate the primary pulmonary causes vs likely cardiac
  • Administer 100% oxygen via hood or PPV for 10- 15 minutes
  • Take the RIGHT radial ARTERIAL BLOOD GAS (pre ductal)
  • Get the PAO2 value
    • CARDIAC SHUNTING is likely if PAO2 <150mmHg (torr)
    • PULMONARY CAUSE is likely if  PAO2 >150mmHg (torr)

GOALS for the Cyanotic Neonates are as follows:

• STABILIZE THE PATIENT and DIAGNOSE DEFECT
  • Resuscitation
  • Start prostaglandin to keep PDA open (if indicated)
  • Correct acid base balance, sugar, electrolytes, temperature
• DO EMERGENT PROCEDURES
  • BAS
  • PDA stenting/ RVOT stenting/ PPBV
  • BT shunt
  • Neonatal corrective surgery
• OPTIMIZE and PLAN LONG TERM MANAGEMENT

Older infants and children with cyanotic emergencies are usually because of hypercyanotic spells or TET spells in TOF patients

• Can occur in infants with known or undiagnosed Cyanotic Heart disease
• Usual history of increasing cyanosis in the morning and during periods of crying or heavy play
• The patient may present with Hyperpnea (deep rapid breaths)
• There is Loss or diminishing loudness of the PS murmur
• There can be Progressive cyanosis which can sometimes lead to loss of consciousness and even death

In these patients, there is often an acute imbalance between systemic and pulmonary blood flow which starts the vicious cycle of increased heart rate because of catecholamine release, leading to increased oxygen consumption and decreased mixed venous oxygen. There is also reduced SVR which promotes right to left shunting, causing more hypoxia.

• Fluids – PNSS 10-20ml/kg bolus
• Sedation (Morphine 0.1-0.2mg/kg IM or IV if with line, Ketamine 1mg/kg/dose)
• Beta blocker (Propranolol, Esmolol 500mcg/kg over 1 min then 50mcg/kg/min up to 300mcg/kg/min infusion)
• Vasoconstrictors (Phenylephrine 10mcg/kg bolus, Norepinephrine drip)
• Intubation and ventilation
• Surgery/ interventional procedures
  • Surgery – total correction if anatomy is favorable, or modified Blalock Taussig- Thomas shunt to improve pulmonary blood flow
  • Interventional procedures – PDA stenting for neonates and infants with PDA, RVOT stenting for those with no PDA to stent

Summary of management strategies for Hypercyanotic spells:

Take home points:

• Cyanotic emergencies depend on age of the child
• Neonatal cyanosis is an EMERGENCY!
• Pulse oximetry screening can detect problems before it becomes emergency
• Hyperoxia test can be used to differentiate pulmonary  vs cardiac cyanosis
• Hypercyanotic spells can be LIFE THREATENING and PROMPT MANAGEMENT is essential
• SURGERY and INTERVENTIONAL PROCEDURES are AVAILABLE