The treatment of choice for patients with respiratory failure of neuromuscular origin, especially in patients with hypercapnic respiratory acidosis, is noninvasive ventilation (NIV). Endotracheal intubation and invasive ventilation are indicated for patients with severe respiratory compromise or failure of NIV. In recent years, high-flow oxygen therapy and active humidification devices have been introduced, and emerging evidence suggests that high-flow oxygen may be effective in various clinical settings, such as acute respiratory failure, after cardiac surgery, during sedation and analgesia, in acute heart failure, in hypoxemic respiratory distress, in do-not-intubate patients, in patients with chronic cough and copious secretions, pulmonary fibrosis, or cancer, in critical areas and the emergency department. We report on a patient with amyotrophic lateral sclerosis who arrived at the emergency department with acute hypercapnic respiratory failure. She did not tolerate NIV and refused intubation, but was treated successfully with heated, humidified oxygen via high-flow nasal cannula. Arterial blood analysis after an hour on high-flow nasal cannula showed improved pH, P(aCO2), and awareness. The respiratory acidosis was corrected, and she was discharged after 5 days of hospitalization. Her response to high-flow nasal cannula was similar to that expected with NIV. We discuss the mechanisms of action of heated, humidified high-flow oxygen therapy.

Background:There is little evidence on noninvasive ventilation (NIV) preventing respiratory complications in high-risk patients undergoing endoscopy procedures.Objectives:The objective of this study is to demonstrate that the application of NIV through a nasal interface can prevent the appearance of ventilatory alterations during endoscopic retrograde cholangiopancreatography (ERCP) in patients with risk factors associated with the development of hypoventilation.Patients and Methods:A non-randomized interventional study was performed on 37 consecutive high-risk patients undergoing ERCP. During the procedure, 21 patients received oxygen by nasal cannula (3 L/minute) and sixteen received NIV through a nasal mask. Arterial blood gas analyses were conducted before and immediately after the ERCP. An Acute Physiology and Chronic Health Evaluation (APACHE) score pre-ERCP was recorded. The complications during the procedure were recorded.Results:The groups with and without NIV were comparable. A post-ERCP pH of <7.35 was found in eight patients, who did not receive ventilatory support (38.1%) compared to zero patients in the NIV group (P = 0.006). A post-ERCP pCO2 >45 mmHg was found in one case (6.3%) in the NIV-group and in nine cases in the nasal cannula group (42.9%; P = 0.01). The median pCO2 post-ERCP was lower (36.5 ± 6.2 vs. 44.5 ± 6.8 mmHg) (P = 0.001) and median pH post-ERCP was higher (7.41 ± 0.4 vs. 7.34 ± 0.5) (P = 0.001) in patients treated with NIV. In the multivariate analysis, after adjusting for gender, the APACHE score, pH and pCO2 pre-ERCP, age, propofol doses, and procedure duration, the following differences were maintained (pCO2 difference = 5.54, 95% Confidence Interval (CI) =2.3 – 8.7, pH difference = 0.047, and 95% CI = 0.013 – 0.081). Among the 37 procedures, four complications occurred: One in the NIV group and three in the nasal cannula group. None of them was related to NIV.Conclusions:Our preliminary results demonstrate that in high-risk patients undergoing ERCP, hypercapnia and respiratory acidosis are frequent. NIV prevents the appearance of these complications.

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