Care essential 2: Check ventilator settings and modes

When you enter the patient’s room, take vital signs, check oxygen saturation, listen to breath sounds, and note changes from previous findings. Also assess the patient’s pain and anxiety levels.

Read the patient’s order and obtain information about the ventilator. Compare current ventilator settings with the settings prescribed in the order. Familiarize yourself with ventilator alarms and the actions to take when an alarm sounds. Locate suction equipment and review its use. Look for a bag-valve mask, which should be available for every patient with an artificial airway; be sure you know how to hyperventilate and hyperoxygenate the patient.

Ventilator settings and modes

Generally, ventilators display ordered settings and patient parameters. Check the following settings:

  • respiratory rate, the number of breaths provided by the ventilator each minute. Manually count the patient’s respiratory rate, because she may be taking her own breaths at a rate above the ventilator setting.
  • fraction of inspired oxygen (FiO2), expressed as a percentage (room air is 21%).
  • tidal volume (TV or VT), the volume of air inhaled with each breath, expressed in milliliters
  • peak inspiratory pressure (PIP), the pressure needed to provide each breath. Target PIP is below 30 cm H2O. High PIP may indicate a kinked tube, a need for suctioning, bronchospasm, or a lung problem, such as pulmonary edema or pneumothorax.

To find out which ventilation mode or method your patient is receiving, check the ventilator itself or the respiratory flow sheet. The mode depends on patient variables, including the indication for mechanical ventilation.

Modes include those that provide specific amounts of TV during inspiration, such as assist-control (A/C) and synchronized intermittent mandatory ventilation (SIMV); and those that provide a preset level of pressure during inspiration, such as pressure support ventilation (PSV) and airway pressure release ventilation. PSV allows spontaneously breathing patients to take their own amount of TV at their own rate. A/C and continuous mandatory ventilation provide a set TV at a set respiratory rate. SIMV delivers a set volume at a set rate, but lets patients initiate their own breaths in synchrony with the ventilator.

Some patients may receive adjuvant therapy, such as positive end-expiratory pressure (PEEP). With PEEP, a small amount of continuous pressure (generally from +5 to +10 cm H2O) is added to the airway to increase therapeutic effectiveness. In many cases, PEEP is added to reduce oxygen requirements.

Finally, determine if a capnography monitor is recording the patient’s partial pressure of exhaled carbon dioxide (pCO2). Capnography, which reflects ventilation, can detect adverse respiratory events, such as tracheal-tube malpositioning, hypoventilation, and ventilator circuit problems. The capnography waveform should be square; generally, the value should be in the normal pCO2 range of 35 to 45 mm Hg. (See Normal capnography waveform by clicking the PDf icon above.) To better understand your patient’s ventilation status, check for trends in waveforms and values rather than focusing solely on single events.