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

ALERT

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

OVERVIEW

Pressure-regulated volume control (PRVC) ventilation is designed for invasive mechanical ventilation and 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 breath by breath.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 breath delivered does not meet the VT target, the ventilator responds by adjusting the inspiratory pressure up or down accordingly in small increments in the attempt to meet the VT target setting for the next breath (Figure 1).

The pressure available to achieve the VT target setting is generally 5 cm H₂O below the set upper pressure limit.¹ Consequently, if this set pressure limit is reached before the VT target has been delivered, the ventilator breath is terminated, the pressure limit alarm will sound, and the patient will only 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 mechanical ventilation, lung-protective strategy used to meet acute respiratory distress syndrome (ARDS) management goals by maximizing alveolar recruitment, patient comfort, and patient-ventilator synchrony, while minimizing the risk of barotrauma or volutrauma.^1,4 PRVC can automatically adjust to changes in lung compliance and airway resistance on a breath-by-breath basis. If the patient’s lung compliance decreases or airway resistance increases, the system flow and pressure increase. If lung compliance increases or airway resistance decreases, the system flow and pressure decrease. PRVC provides the comfort and safety of pressure ventilation for patients of all ages with a set target for VT and minute ventilation.

SUPPLIES

See Supplies tab at the top of the page.

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 personal protective equipment (PPE) based on the patient’s need for isolation precautions or the risk of exposure to 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 a 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 and ensure that the patient agrees to treatment.
4. Transition the patient to PRVC or an equivalent mode using the prescribed settings.

   Setting options, terminology, and abbreviations may be brand specific based on trademarked mechanical ventilator specifications.

5. Select the appropriate patient designation (e.g., adult, pediatric, infant).
6. Select and enter the PRVC or equivalent mode depending on the manufacturer’s software.
7. Set the desired minimum respiratory rate.

   The patient may breathe above the set respiratory rate.

8. Set the desired VT target using ideal body weight calculations for lung protective strategy.

   If the VT target is not met, the ventilator responds by adjusting the inspiratory pressure up or down accordingly in small increments in the attempt to meet the VT target for the next breath (Figure 1).

9. Set the desired FIO₂ delivery.
10. Set the desired inspiratory time or inspiratory-to-expiratory (I:E) ratio.
11. Set the desired PEEP level.
12. Set the desired trigger sensitivity (pressure or flow).
13. Set the desired PS, if applicable.
14. Set the upper pressure limit.

    Consider 35 cm H₂O as the initial setting and lung protective strategy because the ventilator should not allow the pressure to rise higher than 5 cm H₂O below the upper pressure limit setting and will signal an alarm.¹

15. Ensure that all ventilator alarms are on and set appropriately for the patient’s individual ventilator settings.
16. Remove PPE and perform hand hygiene.
17. 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 clinical 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 patient-ventilator synchrony.
9. To minimize alveolar derecruitment, consider using a closed-suction device to minimize the number of times the patient is disconnected from the ventilator.
10. Maintain the humidification device 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-ventilator synchrony and comfort
• Minimized ventilator-induced lung injury
• Liberation from mechanical ventilation

UNEXPECTED OUTCOMES

• Alveolar 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
• Patient’s tolerance of appearance
• Education
• Unexpected outcomes and related interventions

REFERENCES

1. Cairo, J.M. (Ed.). (2024). Chapter 5: Selecting the ventilator and the mode. In Pilbeam’s mechanical ventilation: Physiological and clinical applications (7th ed., pp. 62-83). 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: Ventilator initiation. In D.C. Shelledy, J.I. Peters (Eds.), Mechanical ventilation (3rd ed., pp. 311-366). Burlington, MA: Jones & Bartlett Learning.

ADDITIONAL READINGS

Matusov, Y. and others. (2020). Use of pressure-regulated volume control in the first 48 hours of hospitalization of mechanically ventilated patients with sepsis or septic shock, with or without ARDS. Journal of the Intensive Care Society, 21(4), 305-311. doi:10.1177/1751143719878969

Clinical Review: Jennifer Elenbaas, MA, BS, RRT, AE-C

Published: June 2024