Ventilator high pressures: Difference between revisions

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==High Pressure Alarms==
==High Pressure Alarms==
*In volume control mode, (high)pressure alarm sounds. In pressure control mode (low) volume alarm sounds--BOTH signify similar problems and troubleshoot with the following 4 maneuvers.
*In volume control mode, (high)pressure alarm sounds. In pressure control mode (low) volume alarm sounds--BOTH signify similar problems and troubleshoot with the following 4 maneuvers.
===1-Measure Peak Plateau Pressure===
===Measure Peak Plateau Pressure===
*Need to measure peak plateau pressure P(Plat) not only peak airway pressure P(Peak).
*Need to measure peak plateau pressure P(Plat) not only peak airway pressure P(Peak).
**Press and hold the “inspiratory hold” button-waveform shows peak pressure and then lower plateau.
**Press and hold the “inspiratory hold” button-waveform shows peak pressure and then lower plateau.
*P(Plat) >30 thought to be potentially injurious to lung.  
*P(Plat) >30 thought to be potentially injurious to lung.  
*P(Plat) reflects equilibration of airway pressures without flow, accounts for airway resistance.
*P(Plat) reflects equilibration of airway pressures without flow, accounts for airway resistance.
===2-Determine Airway Resistance===
===Determine Airway Resistance===
*When airway resistance high, P(Peak)>> P(Plat)
*When airway resistance high, P(Peak)>> P(Plat)
**Normal P(Peak)-P(Plat) < 5cm H2O
**Normal P(Peak)-P(Plat) < 5cm H2O
***Airway resistance increased with: asthma, mucus plugging, small tube, tube kinking, tube obstructed
***Airway resistance increased with: asthma, mucus plugging, small tube, tube kinking, tube obstructed
===3-Eval for Dynamic Hyperinflation===
===Eval for Dynamic Hyperinflation===
*Flow at end of expiration has not stopped, ie breath stacking, ie need more time to exhale and each breath adding volume to lungs
*Flow at end of expiration has not stopped, ie breath stacking, ie need more time to exhale and each breath adding volume to lungs
*Consequence of dynamic hyperinflation
*Consequence of dynamic hyperinflation
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#Elevated intra-thoracic pressures decrease venous return
#Elevated intra-thoracic pressures decrease venous return
*Look to make sure expiratory flow returns to baseline.
*Look to make sure expiratory flow returns to baseline.
===4-Measure Hyperinflation===
===Measure Hyperinflation===
*If you suspect dynamic hyperinflation, perform “expiratory hold”, then PEEP on vent may be higher than PEEP on vent settings
*If you suspect dynamic hyperinflation, perform “expiratory hold”, then PEEP on ventilator may be higher than PEEP on ventilator settings
*Differences in PEEP with “expiratory hold” and PEEP set on vent suggest hyperinflation.  
*Differences in PEEP with “expiratory hold” and PEEP set on ventilator suggest hyperinflation.  


==Management==
==Management==
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**Kinked tube- pass suction catheter?
**Kinked tube- pass suction catheter?
**Mucus plug- pass suction catheter and suction
**Mucus plug- pass suction catheter and suction
**Bronchospasm- inhaled bronchodilators
**Bronchospasm- inhaled [[bronchodilators]]
**Tube too small- swap tube
**Tube too small- swap tube
=== High P(Peak), Low P(Plat)===
===High P(Peak), High P(Plat)===
*Suggests decreased compliance, not an isolated resistance problem
*Suggests decreased compliance, not an isolated resistance problem
**Mainstem bronchus- pull back ETT, CXR?
**Mainstem bronchus- pull back ETT, [[CXR]]?
**Atelectasis- bronchoscopy
**Atelectasis- bronchoscopy
**Cardiogenic Pulmonary Edema-diuretics vs inotropes
**Cardiogenic [[[pulmonary edema]]-[[diuretics]] vs [[vasopressors|inotropes]]
**ARDS- lower Vt
**[[ARDS]]- lower Vt
**Pneumothorax- Chest Tube
**[[Pneumothorax]]- [[Chest tube]]
**Pneumonia- Antibiotics
**[[Pneumonia]]- [[Antibiotics]]
 
===PEEP measured > PEEP Vent Setting===
===PEEP measured > PEEP Vent Setting===
*Suggests Dynamic Hyperinflation
*Suggests Dynamic Hyperinflation
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**Lower ventilator rate
**Lower ventilator rate
**Shorten I-time to change I:E around 1:4
**Shorten I-time to change I:E around 1:4
** Tidal volume 6-8mL/kg predicted body weight
**Tidal volume 6-8mL/kg [[predicted body weight]]
**Increase inspiratory flow rate to 60-80L/min to allow more exhalation time
**Increase inspiratory flow rate to 60-80L/min to allow more exhalation time
**Opioid sedation blunts intrinsic tachypnea
**[[Opioid]] sedation blunts intrinsic tachypnea
**Treat bronchospasm
**Treat bronchospasm
==Settings==
 
*[[Ventilation (Settings)]]
*[[Ventilation (Weaning)]]
*[[Ventilation (Strategies)]]
==See Also==
==See Also==
*[[Noninvasive Ventilation]]
{{Mechanical ventilation pages}}
*[[Ventilator Desaturation]]
*[[Deterioration After Intubation (DOPE)]]
*[[EBQ:ARDSnet]]
*[[EBQ:ARDSnet]]


[[Category:Airway/Resus]]
[[Category:Critical Care]]
[[Category:Pulm]]
[[Category:Pulmonary]]

Latest revision as of 15:29, 27 September 2019

High Pressure Alarms

  • In volume control mode, (high)pressure alarm sounds. In pressure control mode (low) volume alarm sounds--BOTH signify similar problems and troubleshoot with the following 4 maneuvers.

Measure Peak Plateau Pressure

  • Need to measure peak plateau pressure P(Plat) not only peak airway pressure P(Peak).
    • Press and hold the “inspiratory hold” button-waveform shows peak pressure and then lower plateau.
  • P(Plat) >30 thought to be potentially injurious to lung.
  • P(Plat) reflects equilibration of airway pressures without flow, accounts for airway resistance.

Determine Airway Resistance

  • When airway resistance high, P(Peak)>> P(Plat)
    • Normal P(Peak)-P(Plat) < 5cm H2O
      • Airway resistance increased with: asthma, mucus plugging, small tube, tube kinking, tube obstructed

Eval for Dynamic Hyperinflation

  • Flow at end of expiration has not stopped, ie breath stacking, ie need more time to exhale and each breath adding volume to lungs
  • Consequence of dynamic hyperinflation
  1. Harder to trigger vent- dys-synchrony
  2. Increased dead space- hypoxic/hypercapneic
  3. Elevated intra-thoracic pressures decrease venous return
  • Look to make sure expiratory flow returns to baseline.

Measure Hyperinflation

  • If you suspect dynamic hyperinflation, perform “expiratory hold”, then PEEP on ventilator may be higher than PEEP on ventilator settings
  • Differences in PEEP with “expiratory hold” and PEEP set on ventilator suggest hyperinflation.

Management

High P(Peak), Low P(Plat)

  • Suggests increased airway resistance, not compliance problem
    • Kinked tube- pass suction catheter?
    • Mucus plug- pass suction catheter and suction
    • Bronchospasm- inhaled bronchodilators
    • Tube too small- swap tube

High P(Peak), High P(Plat)

PEEP measured > PEEP Vent Setting

  • Suggests Dynamic Hyperinflation
    • Remove from vent, allow complete exhalation
    • Lower ventilator rate
    • Shorten I-time to change I:E around 1:4
    • Tidal volume 6-8mL/kg predicted body weight
    • Increase inspiratory flow rate to 60-80L/min to allow more exhalation time
    • Opioid sedation blunts intrinsic tachypnea
    • Treat bronchospasm

See Also

Mechanical Ventilation Pages