Physiological impact of high-flow nasal cannula therapy on postextubation acute respiratory failure after pediatric cardiac surgery: A prospective observational study

Background: Reintubation after pediatric cardiac surgery is associated with a high rate of mortality. Therefore, adequate respiratory support for postextubation acute respiratory failure (ARF) is important. However, little is known about the physiological impact of high-flow nasal cannula (HFNC) therapy on ARF after pediatric cardiac surgery. Our working hypothesis was that HFNC therapy for postextubation ARF after pediatric cardiac surgery improves hemodynamic and respiratory parameters. Methods: This was a prospective observational study conducted at a single university hospital. Children less than 48 months of age who had postextubation ARF after cardiac surgery were included in this study. HFNC therapy was started immediately after diagnosis of postextubation ARF. Data obtained just before starting HFNC therapy were used for pre-HFNC analysis, and data obtained 1 h after starting HFNC therapy were used for post-HFNC analysis. We compared hemodynamic and respiratory parameters between pre-HFNC and post-HFNC periods. The Wilcoxon signed-rank test was used to analyze these indices. Results: Twenty children were included in this study. The median age and body weight were 4.5 (2.3-14.0) months and 4.3 (3.1-7.1) kg, respectively. Respiratory rate (RR) significantly decreased from 43.5 (32.0-54.8) to 28.5 (21.0-40.5) breaths per minute (p = 0.0008) 1 h after the start of HFNC therapy. Systolic blood pressure also decreased from 87.5 (77.8-103.5) to 76.0 (70.3-85.0) mmHg (p = 0.003). Oxygen saturation, partial pressure of arterial carbon dioxide, heart rate, and lactate showed no remarkable changes. There was no adverse event caused by HFNC therapy. Conclusions: HFNC therapy improves the RR of patients who have postextubation ARF after pediatric cardiac surgery without any adverse events.