MD Nexus

Invasive Mechanical Ventilation-General Part 4

Disease-Specific Mechanical Ventilation Strategies

Asthma and Chronic Obstructive Pulmonary Disease (COPD) (see Asthma and Chronic Obstructive Pulmonary Disease)

  • Strategies
    • Use Large Size Endotracheal Tube to Minimize the Expiratory Airflow Resistance
    • Use Low Tidal Volumes and Respiratory Rates (Decreasing the Minute Ventilation), Often with Permissive Hypercapnia
      • May Require Sedation (with/without Paralysis)
    • Decrease the I:E Ratio (from 1:3 to 1:5) to Avoid the Development of Auto-PEEP
      • May Require Higher Inspiratory Flow Rate (80-100 L/min)
    • Maintain Plateau Pressure <30 cm H2O
    • Aggressively Manage Ventilator Dyssynchrony
    • Treat Bronchospasm (by Standard Means)

Hypoxemic Respiratory Failure (of Any Etiology) (see Respiratory Failure)

  • Strategies
    • Standard Lung Protective Ventilation Strategy (Low Tidal Volume with Higher PEEP)

Cardiogenic Pulmonary Edema (see Cardiogenic Pulmonary Edema)

  • Strategies
    • Standard Lung Protective Ventilation Strategy (Low Tidal Volume with Higher PEEP)

Acute Respiratory Distress Syndrome (ARDS) (see Acute Respiratory Distress Syndrome)

  • Strategies
    • Standard Lung Protective Ventilation Strategy (Low Tidal Volume with Higher PEEP)
    • Early Administration of Neuromuscular Blockade: may be beneficial

Increased Intracranial Pressure (ICP) (see Increased Intracranial Pressure)

  • Strategies
    • Avoid Hypotension (as This May Decrease the Cerebral Perfusion Pressure)
    • Maintain Normocapnia with pCO2 35-40 mm Hg (and Specifically Avoid Hypercapnia)
      • While Hyperventilation May Be Used for a Brief Period of Time (1-2 hrs) to Manage an Acute Increase in Intracranial Pressure Associated with Herniation Which is Unresponsive to Other Therapies (Mannitol, Sedation/Paralysis, Cerebrospinal Fluid Drainage), Prophylactic Hyperventilation (with pCO2 ≤35 mm Hg) Should Be Avoided in the Setting of Traumatic Brain Injury (TBI), Due to the Potential to Impair Cerebral Perfusion (see Traumatic Brain Injury) (J Neurosurg, 1991)[MEDLINE] (Chest, 2005) [MEDLINE] (Crit Care Med, 2005) [MEDLINE]
      • Permissive Hypercapnia is Contraindicated
    • Maintain Normoxemia

Pregnancy (see Pregnancy)

  • Strategy
    • Target a pCO2 of Approximately 32 mm Hg (Since Pregnant Patients Typically Normally Manifest a Respiratory Alkalosis)
      • Animal Studies Indicate that Decreasing the pCO2 Below this Level May Undesirably Decrease Uterine Blood Flow
      • Permissive Hypercapnia May Be Difficult to Maintain in a Pregnant Patient, But is Gdenerally Safe Up to a pCO2 of 60 mm Hg
    • Higher Levels of PEEP May Be Required in Third Trimester Patients to Prevent Atelectasis

Abdominal Compartment Syndrome (see Abdominal Compartment Syndrome)

  • Strategies
    • Permissive Hypercapnia (with/without Neuromuscular Blockade): may be required to decrease airway pressure and avoid barotrauma
    • Treat Underlying Abdominal Compartment Syndrome (as Required)

Trauma

  • Strategies
    • In the Setting of Shock, Avoid Excessive PEEP and Elevated Plateau Pressure (Both May Decrease Right Ventricular Filling and Cause Hypotension)
    • In the Setting of Lung Trauma, Use Standard Lung Protective Ventilation Strategy (Low Tidal Volume with Higher PEEP)
    • In the Setting of Increased Intracranial Pressure, See Measures Above
    • In the Setting of Abdominal Compartment Syndrome, See Measures Above

Adverse Effects and Complications

Unplanned Extubation

Definition

  • Definition of Unplanned Extubation: premature removal of endotracheal tube
    • Accidental Removal During the Course of Care
      • During Patient Transport
      • During Patient Turning
    • Purposeful Removal by Patient

Epidemiology of Unplanned Extubation

  • Unplanned Extubation is a Marker for Poor Quality of Care
  • Incidence of Unplanned Extubations
    • Study: 0.1-3.6 events per 100 ventilator days (Anesth Analg, 2012) [MEDLINE]
    • Study: 7.5 events per 1000 ventilator days (Am J Crit Care, 2014) [MEDLINE]
  • Reintubation Rate
    • Case-Control Study of the Outcome of Unplanned Extubation (Am J Respir Crit Care Med, 2000) [MEDLINE]: n = 75 patients with unplanned extubation (and 150 matched controls)
      • Of the Unplanned Extubations, 56% of Patients Required Reintubation
        • Of These, 74% Required Reintubation Immediately
        • Of These, 86% Required Reintubation within 12 hrs
      • Of the Unplanned Extubations, 44%) Occurred During Weaning Trials
      • Mortality Rate for Patients with Unplanned Extubation was 40%, as Compared to Controls (31%) (p>0.2)
      • Patients with Unplanned Extubation Had a Longer Duration of Mechanical Ventilation (19 vs 11 Days, p<0.01), Longer ICU Length of Stay ((21 vs 14 Days, p<0.05), Longer Hospital Length of Stay ((30 vs 21 Days, p<0.01), and Increased Risk to Require Chronic Care (64% vs 24%, p<0.001)
    • Systematic Review: reintubation rate was 45.8% (range: 1.8-88%) (Anesth Analg, 2012) [MEDLINE]
    • Study: reintubation rate was 27% (Am J Crit Care, 2014) [MEDLINE]
      • Those Who Required Reintubation were Older and Male

Risk Factors for Unplanned Extubation

  • Male Sex
    • Male Sex Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Crit Care, 2011) [MEDLINE]
    • Male Sex Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 4.8) (Anesth Analg, 2012) [MEDLINE]
  • Lower Sedation Level
    • Ramsey Sedation Scale Category 1 and 2 Have Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratios 30 and 25, Respectively) (Crit Care, 2011) [MEDLINE]
    • Lower Sedation Level Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 2.0-5.4) (Anesth Analg, 2012) [MEDLINE]
    • Higher Consciousness Level Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 1.4-2.0) (Anesth Analg, 2012) [MEDLINE]
    • Strategies of No Sedation (and Less So, Intermittent Sedation) Have Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation, as Compared to Patients Receiving Continuous Sedation (with Daily Sedation Vacation) (Am J Crit Care, 2014)[MEDLINE]
      • Agitation Appeared to be Highest in the Intermittent Sedation Group
  • Length of ICU Stay
    • Increased Length of ICU Stay Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Crit Care, 2011) [MEDLINE]
  • Type of Sedation
    • Midazolam Use (at the Time of Unplanned Extubation) Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Crit Care, 2011) [MEDLINE]
  • Restlessness/Agitation
    • Restlessness/Agitation Have Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 3.3-30.6) (Anesth Analg, 2012) [MEDLINE]
  • Use of Physical Restraints
    • Use of Physical Restraints Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 1.4-2.0) (Anesth Analg, 2012) [MEDLINE]
  • Nursing Care
    • Unplanned Extubation Has Been Demonstrated to Occur More Frequently on Night Shift and with the Patient Being Cared for by a Less Experienced Nurses (Anesth Analg, 2012) [MEDLINE]
  • APACHE II Score
    • High APACHE II Score (≥17) Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 9.0) (Anesth Analg, 2012) [MEDLINE]
  • Presence of Chronic Obstructive Pulmonary Disease (COPD)
    • Presence of COPD Has Been Demonstrated to Be Associated with Increased Risk for Unplanned Extubation (Odds Ratio 2.3-2.4) (Anesth Analg, 2012) [MEDLINE]

Consequences of Unplanned Extubation

  • Airway Injury
  • Arrhythmias
  • Aspiration Pneumonia (see Aspiration Pneumonia)
  • Bronchospasm (see Obstructive Lung Disease)
  • Cardiorespiratory Arrest
  • Death
  • Impact on Mortality Rate
    • Patients with Unplanned Extubation Had a Lower Hospital Mortality Rate, as Compared to Patients without Unplanned Extubation (10% vs 30%) (Crit Care, 2011) [MEDLINE]
  • Increased Cost

Prevention of Unplanned Extubation

Preventative Measures

  • 24-hr Bedside Supervision
  • Avoidance of Agitation
  • Change in Method of Endotracheal Tube Securement
  • Daily Awakening Protocols: identifying patients ready for withdrawal from mechanical ventilation
  • Increased Nurse/Patient Ratio
  • Nursing Education
  • Patient Transport Protocols
  • Regular Surveillance
  • Securement of Endotracheal Tube Before Changing Patient Position
  • Sedation Protocols
  • Weaning Protocols

Clinical Efficacy

  • Quality Improvement Programs to Prevent Unplanned Extubation Reduce the Unplanned Extubation Rate by 42% (Range: 22-53%) (Anesth Analg, 2012) [MEDLINE]

Outcome of Mechanical Ventilation

Patients Undergoing Mechanical Ventilation Incur High Healthcare Costs and Sustain Prolonged Disability

  • Duke University One Year Prospective Study of the Outcomes of Patients Undergoing Mechanical Ventilation (Ann Intern Med. 2010;153(3):167 [MEDLINE]: n = 126
    • Approximately 82% of Mechanically-Ventilated Patients Survived Hospitalization
    • The Survivor Patients Had a Median of 4 Separate Hospital Transitions in Postdischarge Care Location
    • Approximately 67% of the Survivor Patients were Readmitted at Least Once
    • Survivor Patients Spent an Average of 74% of All Days Alive in a Hospital or Postacute Care Facility or Receiving Home Health Care
    • At 1 Year, 9% of Patients Had a Good Outcome (Alive with No Functional Dependency), 26% Had a Fair outcome (Alive with Moderate Functional Dependency), and 65% Had a Poor Outcome (Either Alive with Complete Functional Dependency [21%] or Dead [44%])
    • Patients with Poor Outcomes were Older, Had More Comorbid Conditions, and Were More Frequently Discharged to a Postacute Care Facility than Patients with Either Fair or Good Outcomes (P<0.05 for All)
    • Mean Cost Per Patient was $306,135 (SD: $285,467), and Total Cohort Cost was $38.1 million, for an Estimated $3.5 Million Per Independently Functioning Survivor at 1 Year

References

Disease-Specific Mechanical Ventilation Strategies

Unplanned Extubation

Outcome of Mechanical Ventilation