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May.27.2021

Mechanical Ventilation: Pressure-Regulated Volume Control Ventilation (Respiratory Therapy)

ALERT

Don appropriate personal protective equipment (PPE) based on the patient’s signs and symptoms and indications for isolation precautions.

Ventilator failure or accidental disconnection can be catastrophic in patients undergoing neuromuscular blockade.

OVERVIEW

Pressure-regulated volume control (PRVC) ventilation is a mode designed for invasive mechanical ventilation that combines volume and pressure strategies. PRVC delivers a pressure-controlled and tidal volume (VT)-targeted breath using a decelerating flow waveform pattern that allows unrestricted spontaneous breathing with or without pressure support (PS). Setting options, terminology, and abbreviations may be brand specific based on the mechanical ventilator specifications.undefined#ref2">2

PRVC is considered an advanced dual control or adaptive mode because the ventilator uses both volume and pressure to automatically adjust to the patient’s ventilatory needs.1 Pressure, flow, or volume delivery depends on variables such as lung compliance, airway resistance, and respiratory effort.4 The mechanical ventilator delivers the lowest pressure and appropriate flow to meet the set VT target for each delivered breath.1,3 A mandatory rate is set for the patient. The patient may breathe above the set rate. All breaths are patient triggered or time triggered. The ventilator compares volume and pressure values from the previous breath and increases or decreases pressure levels according to tidal or minute ventilation. The pressure level that is delivered is between the set positive end-expiratory pressure (PEEP) and the set upper pressure limit. If the measured volume either increases or decreases above or below the settings, the pressure decreases or increases accordingly in small increments to a maximum determined by the type of ventilator. The pressure available to achieve the targeted volume is generally 5 cm H2O below the set upper pressure limit.1 If this set pressure limit is reached, the ventilator breath is terminated, the pressure limit alarm will sound, and the patient will receive as much of the set volume as possible given the pressure limit. The ventilator adjusts accordingly for the next delivered breath.

PRVC is a lung protective strategy that helps to meet the goals of acute respiratory distress syndrome (ARDS) management, maximizing inspiratory flow needs for improved patient comfort, ventilatory synchrony, and minimizing the risk of barotrauma and volutrauma.1,4 PRVC may be used for the adult, pediatric, and infant populations. If the patient’s lung compliance decreases or airway resistance increases, the system flow and pressure increases. If lung compliance increases or airway resistance decreases, the system flow and pressure decreases. PRVC provides the comfort and safety of pressure ventilation for patients of all ages with a target VT and minute ventilation.

EDUCATION

  • Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
  • Explain the need for ventilator changes to the patient and family.
  • Encourage questions and answer them as they arise.

ASSESSMENT AND PREPARATION

Assessment

  1. Perform hand hygiene before patient contact. Don appropriate PPE based on the patient’s need for isolation precautions or risk of exposure of bodily fluids.
  2. Introduce yourself to the patient.
  3. Verify the correct patient using two identifiers.
  4. Assess the patient’s level of consciousness and ability to understand and participate in decisions. Include the patient as much as possible in all decisions.
  5. Assess the patient for PRVC or equivalent mode and signs of ARDS.2
    1. Decreasing partial pressure of arterial oxygen:fraction of inspired oxygen (PaO2/FIO2) ratio
    2. Increasing plateau pressure, peak inspiratory pressure (PIP), or mean airway pressure (MAP)
    3. Bilateral lung infiltrates on a chest radiograph
  6. Assess the patient’s hemodynamic and cardiorespiratory systems.

Preparation

  1. Gather equipment, including the ventilator with PRVC or equivalent mode, circuit, humidification device, filters (if needed), and closed-suction device.
  2. Before initiating the mechanical ventilator, check the system microprocessor or ventilation system. Perform a short self-test as appropriate.
    1. Verify compliance of the ventilator circuit with the humidification device and filters (if needed).
    2. Document the completed ventilation system test. Include pass or fail, date, initials or signature, and credentials.
  3. Verify the authorized practitioner’s order for the initiation of mechanical ventilation.

PROCEDURE

  1. Perform hand hygiene and don gloves. Don additional PPE based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
  2. Verify the correct patient using two identifiers.
  3. Explain the procedure to the patient and ensure that he or she agrees to treatment.
  4. Transition the patient to PRVC or an equivalent mode using the prescribed settings.
  5. Setting options, terminology, and abbreviations may be brand specific based on trademarked mechanical ventilator specifications.
  6. Select the appropriate patient designation (e.g., adult, pediatric, infant).
  7. Select and enter the PRVC or equivalent mode depending on the manufacturer’s software.
  8. Set the desired minimum respiratory rate.
  9. The patient may breathe above the set respiratory rate.
  10. Set the desired target VT.
  11. If the measured volume either increases or decreases above or below the settings, the pressure decreases or increases accordingly in small increments to a maximum determined by the type of ventilator.
  12. Set the desired FIO2 delivery.
  13. Set the desired inspiratory time or inspiratory-to-expiratory (I:E) ratio.
  14. Set the desired PEEP level.
  15. Set the desired trigger sensitivity (pressure or flow).
  16. Set the desired PS, if applicable.
  17. Set the upper pressure limit.
  18. Ensure that all ventilator alarms are on and set appropriately for the patient’s individual ventilator settings.
  19. Set up the closed-suction system.
  20. Adjust the ventilator settings based on patient’s peripheral oxygen saturation (SpO2), end-tidal carbon dioxide (ETCO2), arterial blood gas (ABG) values, VT, PIP, and clinical status.
  21. Remove PPE and perform hand hygiene.
  22. Document the procedure in the patient’s record.

MONITORING AND CARE

  1. Regularly perform a check of ventilator settings and measured parameters.
  2. Ensure that all ventilator alarms are on and set appropriately for the patient’s individual ventilator settings.
  3. Monitor the ventilator waveforms to evaluate spontaneous and delivered pressure, inspiratory and expiratory flow patterns, and volumes.
  4. Monitor the patient’s SpO2, ETCO2, and hemodynamic status.
  5. Monitor plateau pressure, PIP, and MAP. Report increases in ventilating pressures.
  6. Assess the patient’s mandatory and spontaneous respiratory rate, exhaled minute volume, and VT.
  7. Monitor the patient’s ABG values as needed.
  8. Assess the patient’s overall level of comfort and ventilator synchrony.
  9. To minimize lung derecruitment, consider using a closed-suction device to minimize the number of times the patient is disconnected from the ventilator.
  10. Maintain humidification devices and circuit temperature (if applicable) to avoid excessive condensation in the ventilator circuit.
  11. Observe the patient for signs and symptoms of pain. If pain is suspected, report it to the authorized practitioner.

EXPECTED OUTCOMES

  • Improved oxygenation
  • Improved ventilation
  • Improved patient comfort
  • Decreased work of breathing
  • Minimize ventilator-induced lung injury
  • Liberation from mechanical ventilation

UNEXPECTED OUTCOMES

  • Lung overdistention
  • Increased work of breathing
  • Worsening oxygenation
  • Worsening ventilation
  • Ventilator associated event
  • Hemodynamic compromise

DOCUMENTATION

  • Set target VT
  • Set respiratory rate
  • Set FIO2
  • Set inspiratory time or I:E ratio
  • Set PEEP level
  • Set trigger sensitivity
  • Set PS, if applicable
  • Set upper pressure limit
  • Exhaled VT (mandatory breath)
  • Exhaled VT (spontaneous breath)
  • Minute volume (total)
  • Minute volume (spontaneous)
  • Respiratory rate (total)
  • PIP
  • Plateau pressure
  • MAP
  • Humidification device and associated parameters
  • SpO2
  • ETCO2 (optional)
  • Patient’s tolerance of appearance
  • Education
  • Unexpected outcomes and related interventions

REFERENCES

  1. Cairo, J.M. (2020). Chapter 5: Selecting the ventilator and the mode. In Pilbeam’s mechanical ventilation: Physiological and clinical applications (7th ed., pp. 58-79). St. Louis: Elsevier.
  2. Hess, D.R., Kacmarek, R.M. (Eds.). (2019). Chapter 8: Advanced modes of mechanical ventilation. In Essentials of mechanical ventilation (4th ed., pp. 73-86). New York: McGraw-Hill Education.
  3. Holt, G.A., Habib, S.A., Shelledy, D.C. (2020). Chapter 3: Principles of mechanical ventilation. In D.C. Shelledy, J.I. Peters (Eds.), Mechanical ventilation (3rd ed., pp. 95-154). Burlington, MA: Jones & Bartlett Learning.
  4. Shelledy, D.C., Peters, J.I. (2020). Chapter 6: Ventilation initiation. In D.C. Shelledy, J.I. Peters (Eds.), Mechanical ventilation (3rd ed., pp. 311-366). Burlington, MA: Jones & Bartlett Learning.
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