When assessing an obese patient, an approach to noninvasive ventilation includes:

1. obtain an arterial blood gas analysis to assess baseline gas exchange.
2. monitor vital signs, gas exchange, respiratory rate, tidal volume, and comfort of the patient.
3. explain the indications of noninvasive ventilation to the patient and the possible outcomes.
4. suggested initial settings are 5 cm H2O of pressure support and 5 cm H2O of PEEP.
a. 1 and 2 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 1, 2, and 4 only

ANS: B
Approach to noninvasive ventilation:
1. Explain the indications of noninvasive ventilation to the patient and the possible outcomes (requirement of intubation or prolonged use of noninvasive ventilation). Explain to the patient that he or she is not allowed to drink or eat anything by mouth until he or she is able to avoid the risk of aspiration during noninvasive ventilation.
2. Obtain an arterial blood gas analysis to assess baseline gas exchange.
3. Fit the mask appropriately. If more than one model is available, quickly check with the patient which one is most comfortable to him or her.
4. Suggested initial settings are 10 cm H2O of pressure support and 10 cm H2O of PEEP.
5. Monitor vital signs, gas exchange, respiratory rate, tidal volume, and comfort of the patient.
6. Gradually increase PEEP in 2 cm H2O increments to improve airway patency and oxygenation (SpO2 > 90%). Check hemodynamics carefully.
7. Gradually increase pressure support in 2 cm H2O increments to improve tidal volume (until 6 to 8 ml/kg of ideal body weight), reduce the respiratory rate (below 25), reduce ventilatory distress, and improve CO2 clearance.
8. Check gas exchange at 60 min. If noticeable improvement has been observed and there is no clinical deterioration, noninvasive ventilation can be continued. If noninvasive ventilation did not improve oxygenation or hypercapnia, the patient should be intubated and mechanically ventilat-ed.