Ventilator Setting for Obstructive Lung Disease

Goal in obstruction (asthma/COPD)

Give the patient time to exhale

Initial vent settings for patient with predicted Ideal Body Weight (IBW) = 70 kg (5'9" male; 5'11" female)

Mode = Volume Assist Control (AC) Tidal volume = 560 mL Inspiratory flow rate = 80 L/min Respiratory rate = 10

FiO2 = 100% PEEP = 0-5 Goal Pplt < 30 cmH2O

Ventilator Mode

Volume Assist Control (AC)

Tidal Volume (Vt)

8 mL/kg Based on ideal body weight (kg)

Inspiratory Flow Rate (IFR)

80-100 L/min

• Increase IFR and ensure adequate sedation if patient uncomfortable or sucking on tube

Respiratory rate (RR)

Start at 10, then adjust to give time to exhale (IMPORTANT)

• Goal I:E of 1:4 or 1:5
• Permissive hypercapnea, as long as pH stays above 7.2
• Prevents air-trapping/auto PEEP

FiO2 & PEEP

Start at FiO2 100% and PEEP 0-5

• Goal SpO2 = 92-95%
• Can usually quickly titrate down the FiO2

Plateau Pressure (Pplt)

• Goal Pplt <30 cm H2O
• Check after initial settings and at regular intervals thereafter
• Technique: Press inspiratory hold button for 0.5 sec and look at pressure gauge
• If Pplt >30 cm H2O, investigate possible air trapping

Air-Trapping (Auto-PEEP)

• Air trapping (auto-PEEP) = gas trapped in alveoli at end-expiration
• Suspect auto-PEEP if P(plat) >30 cm H2O, or if hypotension develops
• First step is to disconnect vent and allow trapped air to escape
• Prevent further air trapping by decreasing RR and increasing expiratory time

EMcrit.org

References

• EMCrit. Available at: http://emcrit.org/podcasts/vent-part-2/ Accessed August 1, 2017.
• Brenner B, Corbridge T, Kazzi A. Intubation and mechanical ventilation of the asthmatic patient in respiratory failure. J Emerg Med. 2009 Aug;37(2 Suppl):S23-34. doi: 10.1016/j.jemermed.2009.06.108. [PubMed]