Noninvasive Positive-Pressure Ventilation To Treat Hypercapnic Coma Secondary to Respiratory Failure

Noninvasive Ventilation for Acute Hypercapnic Respiratory Failure: Is It the Same as in Hypercapnic Coma?—Reply

“…1 The rate of intubation was only 20% (3/15) in subjects who were comatose at admission, in line with the results found by Díaz et al 3 By contrast, the rate of intubation was 81% (13/16) in those who developed delayed coma during NIV (P ϭ .001). Subjects with hypercapnic coma upon admission had similar V T values compared with other subjects (459 Ϯ 175 vs 469 Ϯ 142 mL, P ϭ .82).…”

“…As we used exclusively ICU ventilators, inspiratory positive airway pressure, including pressure support and PEEP, reached 16.5 Ϯ 2.8 cm H 2 O in subjects who were comatose at admission, a value close to that reported in the abovementioned studies. 3,4 We agree that adjustment of an adequate pressure support level is the key setting to reverse hypercapnic coma, and we believe that our good results are due in part to our protocol of adjusting the pressure support level to target a minimal V T , as would average volume-assured pressure support. Altered consciousness at admission does not seem to increase the risk of NIV failure.…”

“…The authors reported 31 (12.8% of all patients studied) hypercapnic coma patients either on admission (15 patients) or during the first 24 h (16 patients). The management of hypercapnic coma patients, which can be measured by the Glasgow coma scale 2 and the Kelly-Matthay scale, 3 differs from that of patients with an altered level of consciousness who have not reached hypercapnic coma, especially regarding the levels of pressure support used during the first hours or target volume.…”

“…It has already been found that NIV can be successful in subjects with hypercapnic coma, and NIV failure rates of only 20% have been reported. 3 It is important to note that patients who succeed with NIV have a faster improvement of consciousness compared with those who need intubation. 3 Dr Briones Claudett emphasizes that subjects with altered consciousness may require higher levels of pressure support than those with normal consciousness.…”

“…3 It is important to note that patients who succeed with NIV have a faster improvement of consciousness compared with those who need intubation. 3 Dr Briones Claudett emphasizes that subjects with altered consciousness may require higher levels of pressure support than those with normal consciousness. To support this, Briones Claudett et al 4 recently found a faster recovery from hypercapnic encephalopathy using ventilatory mode with average volume-assured pressure support compared with pressure support ventilation during NIV due to higher levels of ventilatory assistance and larger tidal volumes (V T ).…”