Ventilators and Vent Alarms

What is the purpose of mechanical ventilation?

Provides positive pressure ventilation.
Used when alveolar ventilation is inadequate by pushing air in and forcing alveoli to expand during inspiration

When are mechanical ventilators used?

Apnea or acute ventilatory failure
Hypoxemia unresponsive to oxygen therapy
Increased work of breathing with respiratory muscle fatigue
Controlled hyperventilation
Improves gas exchange and decreases work of breathing

What are modes of ventilation?

ACMV or CMV – Assist-control mode ventilation (full machine control)
SIMV – Synchronized intermittent mandatory ventilation (machine assists, used for weaning)
CPAP – Continuous positive airway pressure
PEEP – Positive end-expiratory pressure to keep alveoli distended and prevent collapse

What are ventilator settings?

Rate – number of ventilator-delivered breaths per minute plus patient’s own rate
Tidal volume – amount of gas delivered with each ventilator breath
Oxygen concentration – percentage of oxygen delivered (FiO₂ 21–100%)
PEEP – maintains positive pressure in lungs at end of expiration (can cause barotrauma, most dangerous)
Mode – type of assist given by vent (pressure control or SIMV)
FiO₂ – fraction of inspired oxygen being delivered

What are high pressure alarms?

High pressure = blockage
Caused by biting the tube, kinks, excessive secretions, coughing, pulmonary edema, or pneumothorax

What are low pressure alarms?

Low pressure = loss of connection or leak
Caused by cuff leak, ET tube displacement, or disconnection

What are complications from ventilator alarms?

Ventilator-associated pneumonia
Barotrauma
Cardiovascular effects
Gastrointestinal effects

How can we provide nutrition and fluids for respiratory insufficiency patients?

Enteral or parenteral nutrition
Nasogastric, gastrostomy, or jejunostomy tubes used for feeding

What is weaning with ventilators?

Process of removing ventilator support and re-establishing spontaneous respirations
Factors to consider

What are ARDS goals while on ventilation?

Identify and treat the cause
Maintain PaO₂ > 60 mmHg and O₂ saturation > 90% at the lowest possible FiO₂
Prevent oxygen toxicity

Why is mechanical ventilation required?

Respiratory failure due to failure to oxygenate (inadequate gas exchange as seen in ARDS)
Compromised neurologic function (decreased mental status or decreased lung compliance)
Combination of both
Airway protection in cases of respiratory arrest, gasping respirations, or upper airway obstruction (stridor, inhalation injuries)

What is an airway management tool?

Endotracheal Tube (ETT) – placed orally or nasally, passes through vocal cords and sits 2–3 cm above the carina

What is a tracheostomy tube?

Cuffed or cuffless tube inserted into the trachea for long-term airway management

What are airway cuffs used for?

Assist with holding airway in place
Allow positive pressure ventilation without tidal volume loss
Reduce risk of aspiration of oral and gastric secretions
If patient can talk or is losing tidal volume, the cuff may not be fully inflated

What is a high pressure alarm?

High pressure = high blockage
Causes

What is a low pressure alarm?

Tubing disconnected from ventilator
Leaking cuff or tubing connections (if patient can talk around trach, cuff likely leaking)
Extubation
Alarms may also trigger for tidal volume, rate, temperature, or oxygen changes

What are complications of mechanical ventilation?

Asynchrony (“bucking the vent”)
Auto-PEEP causing air trapping and alveolar damage
Barotrauma (alveolar damage from pressure/volume)
Hemodynamic compromise
Nosocomial infection
Anxiety, stress, sleep deprivation
Gastric ulcers, gastritis, malnutrition
Muscle deconditioning and ventilator dependence
Increased intrathoracic pressure causing systemic edema from decreased venous return

What are general principles for ventilation alarms and systems?

Ensure airway remains patent and properly positioned
Assess patient’s oxygenation and ventilation first before the machine
If in distress and problem cannot be found, disconnect from ventilator and manually bag with 100% oxygen
Call for help immediately

What is DOPE?

Displacement of tube
Obstruction (mucus plug or kink)
Pneumothorax
Equipment failure

What is a ventilator alarm checklist?

Check patient first
Check tubing for disconnections or kinks
Suction if needed
Assess cuff inflation and connections
If problem persists or patient is unstable, manually bag patient with 100% oxygen and call for help