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. Author manuscript; available in PMC: 2013 Aug 13.
Published in final edited form as: Crit Care Nurse. 2009 Sep 1;29(6):41–55. doi: 10.4037/ccn2009612

Table 1.

Patient- and ventilator-related factors that affect patient-ventilator interaction

Patient-related factors Ventilator-related factors
Respiratory center output Triggering

  1. Factors that may decrease respiratory drive:

    • Sedative, opioid, hypnotic medications12

    • High level of ventilatory assistance13

    • Metabolic alkalosis12

    • Malnutrition12

    • Sleep deprivation12

    • Severe hypothyroidism12

    • Idiopathic central hypoventilation syndrome12

    • Severe bilateral brainstem injury of mid to lower medulla12

  2. Factors that may increase respiratory drive

    • Chemoreceptor stimulation (hypoxemia, hypercapnia, acidosis states)12

    • Increased ventilatory demand from

      • Increased metabolic states (pain, fever, shivering, overfeeding, sepsis, burns, trauma, hyperthyroidism, metabolic acidosis)12

      • Underlying lung disease12

    • Increased workload (weaning, stimuli that increase demand)12

    • Pain,12 increased psychogenic stimuli or agitation12

    • Medications (theophylline, doxapram, acetazolamide)12

  1. Ineffective trigger

    • Excessive intrinsic positive end-expiratory pressure14

    • Delayed termination dyssynchrony17,18

    • Maladjusted sensitivity level14

  2. Auto-cycling

    • Maladjusted sensitivity level14

    • Excessive water in circuit14

    • Air leaks in endotracheal tube cuff, ventilator circuit, chest tube11

    • Cardiac oscillations19

  3. Double triggering

    • Premature termination dyssynchrony11
Respiratory system mechanics Cycling off

  1. Prolonged patient inspiratory time10

  2. Shortened patient expiratory time10

  3. Weak respiratory muscles,12 poor neuromuscular control,11 wean from high assist

  1. Inappropriately set cycling variable for patient18,20
Disease states and conditions Ventilator causes of patient agitation

  1. Obstructive pulmonary disease, dynamic hyperinflation states causing increased intrinsic positive end-expiratory pressure12

  2. Acute respiratory distress syndrome12

  3. Pain, splinting13,14

  4. Body posture, abdominal distention13

  5. Psychogenic behavioral stimuli causes agitation12 from

    • Pulmonary edema, pulmonary emboli, pneumothorax13

    • Bronchospasm, retained airway secretions13

    • Intensive care unit environment,15 fear, anxiety

  1. Ventilator disconnection13

  2. System leak, circuit malfunction13

  3. Inadequate fraction of inspired oxygen13

  4. Inadequate ventilator support13
Artificial airway in place Dead space

  1. Size, shape,14 narrowing of lumen by secretions16

  2. Cuff leak11,12

  3. Disconnection from circuit12

  1. Increased dead space in circuit causes increased work load and work of breathing12