Noninvasive mechanical ventilation (NIMV) is the support of the ventilation of the patient using kinds of mechanical means but without intubation. The advantages of NIMV are well known (autonomous interruption and adaptation, intervals in use, self-performed, no humidification needed, no sedation, possibility of expectorations, coughing, talking, feeding, and so on) and the disadvantages of IMV (during intubation [spasm, heart attack, dilatation of stomach], during IMV obstruction, ventilator-associated pneumonia [VAP], take-off, after intubation, tracheostomia).
Among different types of NIMV (negative pressure [iron lung], positive pressure [intermittent positive pressure ventilation, spontaneous intermittent mechanical ventilation, PSV, BiPAP, PAV], CPAP), in recent years a face CPAP mask (Boussignac–Vygon) has been developed and used in a mode of CPAP ventilation. An O2 supply is used to create through a special valve mechanism continuous positive pressure in the airways. Although this mask is very effective to correct hypoxemia, it has two serious disadvantages: (1) it uses very high flow of O2 to create an effective CPAP, resulting in an uncontrolled FiO2 more than 60% (up to 95%) in the majority of cases; (2) it cannot be used in COPD II patients because the high FiO2 obligatory used overtreats hypoxemia ending not in correction, but in exacerbation of hypercapnia.
We modified the face mask Boussignac–Vygon (commercially available): we created a new income on the mask to supply O2 in full control of the FiO2 and we use the valve mechanism of the mask to create the CPAP needed, by supplying air (21% O2). The flow of the air was 'guided' from the level of the CPAP we need to create. The flow of O2 was guided from the FiO2 we need to supply in order to oxygenate the patient but not to overtreat him/her.
Our purpose was to be able to fully control (1) the FiO2 of the O2 we supply and (2) the level of CPAP we want to adjust in order to best treat the patient, avoiding the intubation and improve the outcome of the patients.
We treated 58 critically ill patients in Iasis Hospital ICU and classified them in three groups:
1. Postoperative respiratory sedation: six patients (postoperative respiratory insufficiency due to delayed action of anesthesia drugs who were treated with modified-CPAP avoiding re-intubation in all but one).
2. Difficult weaning: seven patients (we succeed to extubate them using m-CPAP although they fulfill the criteria for IMV); no-one was re-intubated.
3. Acute respiratory failure: 45 patients in three subgroups: (a) seven patients postoperative respiratory failure (RF) (one intubated), (b) seven patients cardiogenic RF (three intubated), and (c) 31 patients RF due to pulmonary infection, eight intubated (in this group 11 patients are COPD-II, one intubated)
(1) NIMV using CPAP mask ventilation was successful in 83% of cases. (2) The M-BV CPAP face-mask allows controlled oxygenation in circumstances of CPAP-NIMV. This modification allows it to be used in patients with COPD (type II).