The effect of mechanical ventilation compared to high-flow nasal cannula on gastric residual volume and reflux events using novel automated technology

Background & aim: High flow nasal cannula (HFNC) oxygen therapy is frequently used following extubation. A case report, utilizing an innovative medical technology (The smART + Platform, ART MEDICAL Ltd., Netanya, Israel) that enables the detection of gastric refluxes and gastric residual volumes (GRV), has suggested that HFNC may be associated with increased reflux events and GRV. This study measured reflux events and GRV using smART+ in mechanically ventilated patients before and after extubation while they were receiving HFNC therapy. We aim to show if there is a significant difference in reflux events and GRV between HFNC users and mechanically ventilated patients. Methods: This is a post hoc analysis examines data of a randomized controlled trial (RCT) involving critically ill adult patients who received enteral nutrition through the smART + Platform. The study was approved by the local ethics committee. We compared the frequency and amplitude of reflux events and GRV in mechanically ventilated patients. These parameters were assessed both 3 h before extubation and subsequently after extubation when the patients were connected to HFNC. Patients served as their own controls. To evaluate the differences between the pre- and post-extubation measurements, we applied a parametric paired t-test. Results: Ten patients (mean age of 58 years; mean APACHE II score 22; mean 3.9 days of mechanical ventilation) were included. Three hours prior extubation the mean GRV was 4.1 ml/h compared to 14.03 ml/h on HFNC (p = 0.004). The mean frequency of major reflux events was 2.33/h in ventilated patients versus 4.4/h in the HFNC patients (p = 0.73). The mean frequency of major reflux events was 9.17/h in ventilated patients versus 9.83/h in HFNC patients (p = 0.14). Conclusions: Leveraging the smART + Platform, we demonstrated that the use of HFNC significantly increases GRV compared with patients on mechanical ventilation and may increase the frequency of major reflux events, thereby increasing the risk of aspiration. Further studies are required to support our conclusions.