Options for ventilation:
(1) noninvasive positive pressure ventilation (NIPPV)
(2) conventional mechanical ventilation
Indications for NIPPV:
(1) moderate to severe dyspnea, with use of accessory muscles and with paradoxical abdominal motion
(2) moderate to severe acidosis and hypercapnia (arterial pH < 7.35, PaCO2 > 45 mm Hg)
(3) respiratory rate > 25 breaths per minute
where:
• An arterial pH < 7.35 would just be below the lower end of the normal. Since < 7.25 is the criteria for severe acidosis (below), I will use < 7.30 for moderate in the implementation.
• A PaCO2 > 45 mm Hg is just above the upper limit of the normal reference range. Since > 60 mm Hg is the criteria for severe hypercapnia (below), I will use > 50 in the implementation.
Contraindications for NIPPV:
(1) respiratory arrest
(2) cardiovascular instability
(3) somnolence, impaired mental status, uncooperative patient
(4) high aspiration risk
(5) viscous or copious secretions
(6) recent facial or gastroesophageal surgery
(7) craniofacial trauma
(8) fixed nasopharyngeal abnormalities
(9) extreme obesity
Indications for mechanical ventilation:
(1) severe dyspnea, with use of accessory muscles and with paradoxical abdominal motion
(2) severe acidosis and hypercapnia (arterial pH < 7.25, PaCO2 > 60 mm Hg)
(3) respiratory rate > 35 breaths per minute
(4) life-threatening hypoxemia (PaO2 < 40 mm Hg or PaO2/FIO2 < 200 mm Hg)
(5) contraindications to NIPPV or NIPPV failure
(5a) respiratory arrest
(5b) somnolence, impaired mental status
(5c) cardiovascular instability or complications (hypotension, shock, heart failure, myocardial infarction, cardiac arrhythmias)
(6) other complications
(6a) metabolic abnormalities
(6b) sepsis
(6c) pneumonia
(6d) pulmonary embolism
(6e) barotrauma
(6f) massive pleural effusion
