Mechanical Ventilation: Neonate (Respiratory Therapy)

ALERT

Mechanical ventilation can be associated with acute or chronic respiratory tract injury, such as atelectrauma, volutrauma, barotrauma, oxygen toxicity, and a pulmonary or systemic inflammatory response to lung trauma.

Avoid an irregular respiratory pattern by using an optimum lung volume characterized by using a patient-triggered synchronized ventilation modality.^{undefined#ref1">1} Irregular respiratory patterns in neonates can lead to asynchrony with the ventilator, resulting in high airway pressure, poor oxygenation, and fluctuation in intracranial pressure when the ventilator breath occurs just after the neonate exhales. Lung protective ventilation strategies can minimize ventilator-induced lung injury.²

OVERVIEW

Mechanical ventilation is most commonly required for the extremely low-birth-weight or critically ill neonate. The goals of mechanical ventilation are to facilitate adequate gas exchange, minimize the risk of lung injury, decrease the patient’s work of breathing (WOB), and optimize the patient’s comfort.

There are several basic conventional modes of mechanical ventilation for neonates: synchronized intermittent mandatory ventilation, assist-control ventilation, and pressure-support ventilation. Two modes of ventilation are available for the neonatal population: volume-targeted ventilation and neurally adjusted ventilator assist (NAVA). Volume-targeted ventilation provides a continuous flow of gas throughout inspiration, producing the characteristic “square wave” of flow versus time. Peak pressure and volume delivery occur at the end of inspiration, resulting in slower and more uniform lung inflation. The pressure is varied to deliver the desired volume of gas. NAVA is a mode of ventilation designed to improve patient-ventilator interaction by interpreting a neural signal from the diaphragm to trigger a supported breath. Neurally triggered breaths may reduce trigger delay, ventilator response times, and WOB. These various modes of mechanical ventilation are best classified on the basis of three factors: how each breath is initiated, gas flow during the ventilator breath, and how the breath ends (Table 1).

In addition to the basic conventional modes of mechanical ventilation, there are other high-frequency ventilation (HFV) modes: high-frequency oscillatory ventilation (HFOV) and high-frequency jet ventilation (HFJV). HFV uses small tidal volumes (VTs) and delivers high rates. HFOV’s advantage over conventional mechanical ventilation is the ability to deliver sub-VT breaths at high frequencies. Indications for using HFOV include severe lung disease that is unresponsive to conventional ventilation, pulmonary air leaks, and pulmonary hypoplasia. HFJV is most effective with disorders in which the major problem is carbon dioxide elimination because it can be achieved more readily at a lower peak and mean airway pressure than with HFOV. Severe atelectatic disorders, such as respiratory distress syndrome, and obstructive disorders, such as meconium aspiration syndrome, have been shown to respond to HFJV. The appropriate ventilator mode to be used is based on the individual patient’s clinical condition, disease process, and response to previous ventilatory support (Table 2).

EDUCATION

• Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
• Explain the purpose for and complications of mechanical ventilation.
• Provide descriptions and explanations of the equipment and alarms.
• Discuss the need for suctioning and explain the procedure to the family.
• Discuss methods the family may use to interact with and calm their neonate.
• Explain the need for sedation while on mechanical ventilation.
• Encourage questions and answer them as they arise.

ASSESSMENT AND PREPARATION

Assessment

1. Perform hand hygiene before patient contact.
2. Introduce yourself to the family.
3. Verify the correct patient using two identifiers.
4. Assess the family’s understanding of the reasons for and the risks and benefits of the procedure.
5. Inspect the ventilator equipment and settings.
   1. Review these parameters when using conventional ventilation: fraction of inspired oxygen (FIO₂), ventilator rate, positive inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), VT, inspiration-to-expiration ratio, flow rate, and mean airway pressure (MAP) (Table 3).
   2. Review these parameters when using HFV: FIO₂, amplitude, frequency, and MAP (Table 3).
6. Assess ventilator alarm status.

Preparation

1. Ensure that an appropriate-size manual ventilation bag or manual resuscitator, mask, and suction are immediately available and connected at the patient’s bedside. Test for functionality.
2. Ensure that the patient is in a developmentally and clinically appropriate position.

   Rationale: Elevating the head of the bed may reduce the risk of aspiration and the risk of intraventricular hemorrhage.

PROCEDURE

1. Perform hand hygiene and don gloves.
2. Verify the correct patient using two identifiers.
3. Explain the procedure to the family and ensure that they agree to treatment.
4. Ensure that the authorized practitioner provides the appropriate sedation and pain medications.
5. Evaluate the patient’s vital signs and cardiopulmonary status, including spontaneous respiratory rate, chest expansion or vibration, and response to mechanical ventilator rates.
6. Auscultate the patient’s breath sounds, including upper and lower lung fields and differences in left and right lung fields, to evaluate for the equality of aeration and the presence of adventitious breath sounds.
7. Observe the chest wall vibration when HFV is in use.

   Rationale: Chest wall vibration is an indicator of lung compliance, airway patency, and effectiveness of ventilator settings. A sudden decrease in chest wall vibration may indicate a plugged endotracheal (ET) tube or a pneumothorax.

8. Place the HFV on standby to assess heart sounds and manually ventilate the patient to assess breath sounds.

   Rationale: Volume and tone of HFV breath sounds affect the ability to auscultate heart sounds.

9. Examine the patient for signs and symptoms of ventilatory failure, including increased arterial partial pressure of carbon dioxide (PaCO₂) with decreasing pH, increased WOB, tachypnea, and increased retractions.
10. Examine the patient for signs and symptoms of hypoxemia, including decreased oxygen saturation, pale or cyanotic color, tachycardia or bradycardia, tachypnea, agitation, increased WOB, increased retractions, and acidosis.
11. Note the position of the ET tube and depth markings.
12. Review radiographic findings, arterial blood gas (ABG) analysis, and the patient’s clinical status for indications that ventilator weaning can be initiated.
13. Evaluate the need for suctioning.
14. Adjust ventilator settings as ordered on the basis of treatment protocols or strategies and the patient’s response in collaboration with the authorized practitioner.

    Rationale: Changes in lung compliance may occur, resulting in the need for more or less ventilator support.

    Keep in mind that the goal is to wean the patient from the ventilator as soon as possible to minimize lung injury.

15. Suction the ET tube using the safe suction depth, preferably with an inline suction device.

    Rationale: Using the safe suction depth ensures that the suction catheter is not inserted beyond the end of the ET tube, protecting the soft tissue of the carina from injury.

    1. Suction as needed, not on a routine schedule.

       Rationale: Suctioning is not a benign procedure; therefore, it should be done only as needed to maintain airway patency and remove secretions.

    2. Observe and document the characteristics of secretions.
16. Discard supplies, remove gloves, and perform hand hygiene.
17. Document the procedure in the patient’s record.

MONITORING AND CARE

1. Review the ventilator settings at the beginning of each shift and with every vital sign assessment.
2. Confirm the activation of all alarms at the beginning of each shift.
3. Monitor and document oxygen saturation per the organization’s practice.
4. Monitor blood gases as indicated. In general, ABGs are obtained within a few hours after initiation of assisted ventilation, after significant changes in ventilation settings, and with changes in the patient’s condition.
5. Provide oral care when performing hands-on care, per the organization’s practice.
6. Confirm ET tube stability and centimeter marking at the gumline or lip line once per shift and as needed.
7. Respond immediately to ventilator alarms and watch for changes and fluctuations in prescribed settings, which may indicate water in the tubing or the need for suctioning.

   Rationale: An alarm may be associated with the need for suctioning or the need to drain water from the tubing, or it may indicate that the ventilator tubing has been disconnected.

8. Monitor for signs of unplanned extubation, including sudden deterioration in clinical status, abdominal distention, crying, decreased chest wall movement, breath sounds in the abdomen, agitation, cyanosis, or bradycardia.
9. Observe the patient for signs and symptoms of pain. If pain is suspected, report it to the authorized practitioner.
10. Assess the patient’s readiness for weaning and extubation.

EXPECTED OUTCOMES

• Adequate oxygenation and ventilation
• Maintenance of adequate pH and PaCO₂
• Oxygenation and ventilation without lung injury
• Hemodynamic stability
• Proper placement of ET tube
• Mobilization and removal of secretions
• Weaning from and termination of mechanical ventilation as soon as patient is physiologically ready

UNEXPECTED OUTCOMES

• Inadequate ventilation and oxygenation (hypoxemia, hypercarbia, acidosis, alkalosis)
• Lung overinflation (air-leak syndrome)
• Acute lung injury (barotrauma, volutrauma, or progression of lung disease)
• Atelectasis
• Hemodynamic instability
• Unplanned extubation or malposition of ET tube
• Ventilator-associated pneumonia
• ET tube obstruction
• Inadequately managed pain and agitation due to presence of ET tube or hypoxemia

DOCUMENTATION

• Cardiopulmonary assessment
• Vital signs
• Lung sounds
• WOB
• Capillary or arterial blood gases
• Pulse oximetry
• Date, time, and response to initiation of ventilator assistance
• Conventional ventilator settings, if appropriate, including FIO₂, mode, VT, intermittent mandatory ventilation, PIP, rate, and PEEP
• HFV settings, if appropriate, including FIO₂, amplitude, frequency, and MAP
• Timing of suctioning
• Characteristics of ET tube secretions
• Patient’s response to suctioning
• Assessment of breath sounds after suctioning
• Additional interventions and patient’s response
• Comfort assessment and any specific interventions provided
• Education
• Unexpected outcomes and related interventions

REFERENCES

1. Kacmarek, R.M. (2021). Chapter 49: Initiating and adjusting invasive ventilatory support. In R.M. Kacmarek, J.K. Stoller, A.J. Heuer (Eds.), Egan’s fundamentals of respiratory care (12th ed., pp. 1072-1104). St. Louis: Elsevier.
2. Ozer, E.A. (2020). Lung-protective ventilation in neonatal intensive care unit. Journal of Clinical Neonatology, 9(1), 1-7. doi:10.4103/jcn.JCN_96_19

ADDITIONAL READINGS

Walsh, B.K., Chatburn, R.L. (2019). Chapter 17: Invasive mechanical ventilation of the neonate and pediatric patient. In B.K. Walsh (Ed.), Neonatal and pediatric respiratory care (5th ed., pp. 301-337). St. Louis: Elsevier.