Ventilator Management

• Two Strategies of Ventilation:
  • Injury:
    • This strategy is for patients with lung injury and those prone to lung injury
      • Essentially this means every intubated patient:
        • Except those with obstruction
  • Obstruction:
    • Use this strategy when patients are in the midst of an Asthma / COPD exacerbation
• Injury Strategy:
  • Based on ARDSnet:
    • ARMA Study:
      • N Engl J Med 2000;342,1301-1308
  • Mode:
    • Assist Control (AC)-Volume
  • Tidal Volume (Vt):
    • Equals:
      • Protection
    • Start at 6 to 8 ml / kg:
      • Based on PBW
    • If ALI / ARDS:
      • The goal is to get down to 6 mo / kg:
        • Why?
          • Injured lungs are baby lungs
    • This setting should not be altered:
      • To fix ventilation
    • It only gets changed:
      • For lung protection/
        • To prevent:
          • Barotrauma / volutrauma
  • Flow Rate (IFR):
    • Equals:
      • Comfort
    • Start at 60 to 80 liters per minute (lpm)
    • This setting controls:
      • How quickly the air goes in
  • Rate (RR):
    • Equals:
      • Ventilation
    • Initially start at 16 to 18 breaths per minute (bpm):
      • Adjust based on:
        • CO2 and ventilatory needs
    • Alveolar gas volume (Va):
      • For maintaining normal CO2 when not intubated:
        • Is 60 ml /kg / min
      • We need to double that:
        • To 120 cc/kg/min:
          • When intubated because of:
            • Increased deadspace:
              • Need double that volume (240 ml /kg / min) to send CO2 from 40 to 30
      • Try to keep mildly hypercarbic
  • FiO2/PEEP:
    • Equals:
      • Oxygenation
    • Start at:
      • 100% FiO2 and PEEP of 5
    • Wait 5 minutes:
      • Then draw an ABG
    • Then set the FiO2 between 30% to 40%:
      • Start titrating:
        • Based on the ARDS Net protocol chart:
        • Go up every 5 to 10 minutes:
          • Quicker if low saturation
            
    • Oxygenation goal:
      • PaO2 between:
        • 55 mmHg to 80 mmHg
      • SpO2 between:
        • 88% to 95%
    • Use a minimum PEEP of:
      • 5 cm H2O
    • Consider use of incremental FiO2 / PEEP combinations such as shown below to achieve goal:

• Check Plateau Pressure:
  • Check it after:
    • Initial settings and at regular intervals thereafter
  • Use the inspiratory hold button:
    • Hold for 0.5 seconds:
      • Look at pressure gauge
  • The peak pressure:
    • Is essentially meaningless
  • Plateau pressure:
    • Must be maintained less than 30 cm H20
  • Keep lowering the tidal volume (Vt):
    • Until Plat less than 30 cm H20:
      • You may need to go as low as 4 ml / kg
  • Disadvantages of this strategy:
    • It is not the most comfortable strategy of ventilation for awake, spontaneously breathing patients:
      • Use sedation / pain medications
    • Give enough flow:
      • If you see the patient sucking the straw:
        • Increase the IFR setting
• Obstructive Strategy:
  • Goal is to:
    • Give as much expiratory time as possible
  • Mode:
    • Assist Control
  • Vt:
    • 8 ml / kg by PBW
  • IFR:
    • 80 to 100 lpm
  • PEEP:
    • 0 to 5 cmH20
  • FiO2:
    • Use whatever you need:
      • Most use 40%
  • RR:
    • Start at 8 to 10 bpm:
      • Look for:
        • I:E of 1:4 or 1:5:
          • Adjust the rate to achieve this
• Permissive Hypercapnia:
  • Patients will need a lot of sedation / opioids
  • Keep pH above:
    • 7.1:
      • Rarely:
        • You may need a bicarbonate drip to accomplish this
• AutoPEEP and Airtrapping:
  • They decrease venous return
  • Impede expiration
  • Impede spontaneous ventilation

• Other Concerns:
  • Large Tubes:
    • At least size 8.0 ET whenever possible:
      • For both male and female patients.
    • Pulmonary toilet and ICU care:
      • Is miserable with small tubes
      • Biofilm forms:
        • Within the first two days reducing tube size dramatically
• Ventilator Alarms:
  • Treat them like a code announcement:
    • The closest person should run to the patients bedside and assess the situation.

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