8.2 Advanced Resuscitation: Chest Compressions & Emergency Medications

8.2 Advanced Resuscitation: Chest Compressions & Emergency Medications

Clinical Pearl & Core Takeaway: In neonatal resuscitation, chest compressions and emergency medications will never be effective unless the lungs are already adequately ventilated and inflated. If the heart rate is < 60 bpm, the primary defect is almost always uncorrected hypoxemia and inadequate alveolar ventilation. Before initiating compressions, ensure that effective PPV is being delivered—evidenced by bilateral chest rise—preferably via an secured endotracheal tube or laryngeal mask airway.

1. Assessing PPV Efficacy & The MR. SOPA Corrective Steps

The infant's heart rate response is the single most sensitive indicator of successful ventilation. The 9th Edition lengthened the first assessment interval: the team now assesses heart rate 15 to 30 seconds after starting ventilation (the 8th Edition said 15 seconds), which allows a genuinely effective inflation sequence to be established before the corrective steps are triggered:

1. First Heart Rate Check (After 15 to 30 seconds of ventilation):
   • If HR is rising: Announce "Heart rate is rising." Continue PPV for another 15 to 30 seconds and reassess.
   • If HR is NOT rising, but the chest IS moving: Announce "Heart rate is not rising, but chest is moving." Continue PPV that moves the chest for another 15 to 30 seconds and reassess.
   • If HR is NOT rising, and the chest is NOT moving: Announce "Heart rate is not rising, chest is NOT moving." Immediately stop and perform the MR. SOPA Ventilation Corrective Steps.

The MR. SOPA Troubleshooting Matrix

MR. SOPA is traditionally executed in paired steps, delivering 5 positive pressure breaths after each pair and observing for chest movement. The 9th Edition removed the requirement to run the steps in strict sequence: based on your assessment of the infant and the clinical situation, you may choose the steps most likely to be helpful and prioritize the order in which you perform them. For example, if you can see that the mouth is full of secretions, go to S first rather than working mechanically through M and R.

2. Advanced Airway: Endotracheal Intubation & Laryngeal Mask Airway

When bag-mask ventilation is ineffective (fails MR. SOPA), prolonged PPV is required, chest compressions are indicated, or specific clinical conditions exist (e.g., Congenital Diaphragmatic Hernia), an alternative airway must be established.

Endotracheal Equipment & Sizing Chart

The 9th Edition re-keyed this table to grams rather than kilograms, added a dedicated row for infants under 800 grams, and raised the weight cut-offs (2.5 mm now extends to 1,200 g and 3.0 mm to 2,200 g):

Intubation Procedure & Depth Estimation

• Intubation Attempt Duration: Limit each intubation attempt to < 30 seconds. If unsuccessful within 30 seconds, stop, resume bag-mask PPV, re-oxygenate, and attempt again.
• Depth of Insertion Estimation:
  1. Weight-Based Formula: Estimated insertion depth (cm) = $\text{Estimated Weight in kg} + 6\text{ cm}$ (e.g., a 1 kg infant is intubated to 7 cm; a 2 kg infant to 8 cm; a 3 kg infant to 9 cm).
  • Where the depth mark is read (changed in the 9th Edition): insert the tube so that the marking corresponding to the estimated depth sits at the anterior edge of the baby's upper (maxillary) gum in the midline — "tip-to-gum." The 8th Edition measured to the lip, a soft, mobile landmark that shifts with tape and mask pressure; the gum line is a fixed bony reference and yields a more reproducible depth.
  1. Nasal-Tragus Length (NTL) Method: Measure distance from the nasal septum to the tragus of the ear (cm) and add 1 cm: $\text{Depth (cm)} = \text{NTL} + 1\text{ cm}$.

Confirmation of Endotracheal Tube Placement

• Primary Confirmation ($Et\text{CO}_2$ Detection): Attach a colorimetric end-tidal $\text{CO}_2$ detector between the ETT and resuscitator. A distinct color change from purple/blue (room air) to yellow (exhaled $\text{CO}_2$) during 5 to 6 consecutive positive pressure exhalations confirms tracheal placement. (Note: In infants with cardiac arrest or severely reduced pulmonary blood flow, $Et\text{CO}_2$ may remain pale purple/tan until cardiac output improves).
• Secondary Clinical Confirmation: Rapidly rising heart rate; bilateral symmetric chest excursions; equal breath sounds auscultated in both axillae with absence of gastric gurgling.
• Radiographic Confirmation: Post-resuscitation chest X-ray must demonstrate the ETT tip in the mid-trachea at the level of the T2 to T3 vertebral bodies, well above the carina (T4).

Laryngeal Mask Airway (LMA / Supraglottic Airway)

• Primary device status (changed in the 9th Edition): the laryngeal mask is no longer a rescue-only airway. The 9th Edition states that in most cases ventilation is initiated with a face mask or a laryngeal mask — you may reach for it as a primary device rather than waiting until the face mask and intubation have both failed. This matters in Level I/II settings where a skilled intubator may not be immediately available.
• Indications: Newborns born at ≥ 34 weeks gestation and weighing ≥ 1.5 to 2.0 kg; particularly valuable when facial malformations (e.g., Pierre Robin sequence, cleft lip/palate, micrognathia) prevent a tight mask seal or when endotracheal intubation is unsuccessful ("cannot ventilate, cannot intubate").
• Size: Size 1 supraglottic mask; inserted blindly over the tongue until seated over the laryngeal inlet, and inflated with up to 2 to 4 mL of air.

3. Chest Compressions in Neonatal Resuscitation

Chest compressions are indicated only when the heart rate remains < 60 bpm despite at least 30 seconds of effective positive pressure ventilation that moves the chest (preferably delivered through an endotracheal tube or laryngeal mask).

Compression Technique & Mechanics

• Two-Thumb Encircling-Hands Technique (Gold Standard):
  • The rescuer stands at the head or side of the bed, encircling the neonate's thorax with both hands.
  • Both thumbs are placed on the lower third of the sternum, located immediately below the intermammary nipple line and above the xiphoid process.
  • The fingers support the infant's back to provide a firm counter-support surface.
  • The two-finger compression method is inferior (generates lower peak arterial pressures and exhausts the provider) and should only be used temporarily if umbilical line placement requires subxiphoid access.
• Depth of Compression: Depress the sternum approximately one-third of the anterior-posterior (AP) diameter of the chest.
• Recoil: Allow full chest recoil between compressions; do not remove thumbs from the chest wall.

Ratio, Cadence, & Oxygen Concentration

• Compression-to-Ventilation Ratio: 3:1 ratio (3 compressions to 1 positive pressure breath).
• Frequency: Deliver 90 compressions and 30 breaths per minute (total of 120 events per minute). This provides 2 seconds per cycle (3 compressions over 1.5 seconds, 1 breath over 0.5 second).
• Verbal Cadence: Rescuers count aloud in synchronized rhythm: "One-and-two-and-three-and-breathe; One-and-two-and-three-and-breathe..."
• Oxygen Concentration ($ ext{FiO}_2$): When chest compressions are initiated, immediately increase $\text{FiO}_2$ to 100% on the oxygen blender. Once heart rate recovers above 60 bpm and compressions stop, titrate $\text{FiO}_2$ back down based on target pre-ductal $SpO_2$.

Evaluation & Timing

• Continue coordinated CPR (compressions and PPV with 100% $\text{FiO}_2$) for 60 continuous seconds before pausing briefly to evaluate the heart rate.
• Assess heart rate using 3-lead ECG (preferred) or auscultation. Stop compressions once the heart rate is ≥ 60 bpm.

4. Emergency Medications & Volume Expansion

If the infant's heart rate remains < 60 bpm despite at least 60 seconds of coordinated chest compressions and effective PPV with 100% $\text{FiO}_2$, emergency medications and volume expansion are indicated.

Epinephrine (Adrenaline)

Epinephrine stimulates $\alpha$-adrenergic receptors, causing peripheral vasoconstriction that increases aortic diastolic pressure and drives coronary and cerebral perfusion during CPR.

+-------------------------------------------------------------------------------------------------------+
|                                 EPINEPHRINE DOSING PROTOCOL (NRP 9th Ed.)                             |
|                                                                                                       |
|   Concentration: 1:10,000 (0.1 mg/mL)                                                                 |
|                                                                                                       |
|   [PREFERRED] IV or IO Route:                                                                         |
|   * Dose: 0.02 mg/kg (= 0.2 mL/kg of 1:10,000 solution)                                              |
|   * Dosing Range: 0.01 to 0.03 mg/kg (0.1 to 0.3 mL/kg)                                              |
|   * Follow immediately with a 3 mL Normal Saline flush to clear line                                 |
|                                                                                                       |
|   [TEMPORARY ONLY] Endotracheal (ET) Route:                                                           |
|   * Dose: 0.1 mg/kg (= 1.0 mL/kg of 1:10,000 solution)                                               |
|   * Dosing Range: 0.05 to 0.1 mg/kg (0.5 to 1.0 mL/kg)                                               |
|   * Do NOT flush with saline; deliver several positive pressure breaths to distribute into lungs     |
|                                                                                                       |
|   Repeat Dosing: Every 3 to 5 minutes if HR remains < 60 bpm (Titrate IV doses up to 0.03 mg/kg)     |
+-------------------------------------------------------------------------------------------------------+

Volume Expansion

• Indications: Suspected acute blood loss or hypovolemic shock (e.g., maternal placental abruption, vasa previa, cord rupture, feto-maternal hemorrhage) accompanied by persistent bradycardia, pale/mottled skin, prolonged capillary refill (> 3 seconds), or weak/absent pulses unresponsive to ventilation and compressions.
• Fluid of Choice:
  • 0.9% Sodium Chloride (Normal Saline) — crystalloid of choice.
  • Emergency uncrossed Type O, Rh-negative Packed Red Blood Cells (PRBCs) — indicated for documented severe acute fetal hemorrhage.
• Dose & Administration: 10 mL/kg IV or IO, administered as a steady infusion over 5 to 10 minutes. (Caution: In extreme preterm infants, rapid boluses < 5 minutes can cause sudden cerebral blood flow surges and intraventricular hemorrhage).

Emergency Vascular Access

1. Emergency Umbilical Venous Catheter (UVC):
   • The umbilical vein is a single, large, thin-walled vessel located at the 12 o'clock position in the cord stump (compared to the two smaller, thick-walled muscular umbilical arteries at 4 and 8 o'clock).
   • Catheter Size: 3.5 Fr (< 3.5 kg) or 5.0 Fr (≥ 3.5 kg).
   • Insertion Depth: Insert catheter 2 to 4 cm (or until free blood return is obtained upon aspiration with a syringe). This is a "low emergency placement" positioned below the liver in the inferior vena cava or ductus venosus to avoid hepatic necrosis from hypertonic infusions.
2. Intraosseous (IO) Needle Access:
   • Placed when umbilical venous catheterization is difficult or impossible.
   • Anatomical Site: Proximal tibia, on the flat anteromedial surface 1 to 2 cm below and medial to the tibial tuberosity.
   • Delivers fluids and emergency medications directly into the medullary venous plexus.

Resuscitation Cessation Guidelines

According to NRP 9th Edition guidelines, if the infant's heart rate remains completely absent (0 bpm) after 20 minutes of continuous, high-quality resuscitation (confirming that all steps of ventilation, intubation, compressions, epinephrine, and volume have been properly executed), cessation of resuscitation efforts is ethically and clinically appropriate in consultation with the team and family.